To see the other types of publications on this topic, follow the link: Paper machine.
Dissertations / Theses on the topic 'Paper machine'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 dissertations / theses for your research on the topic 'Paper machine.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.
1
Piltonen, P. (Petteri). "Prevention of fouling on paper machine surfaces." Doctoral thesis, Oulun yliopisto, 2013. http://urn.fi/urn:isbn:9789526202877.
Full textAbstract:
Abstract Fouling in papermaking causes major economic drawbacks due to downtime of process and paper quality defects. The surface fouling is a complex phenomenon in a paper making process, which is affected by several interconnected factors such as process environment changes from wet to dry with increasing temperature along with the variety of sticky materials present in paper raw materials. These impurities, such as waxes, coating binders, hot melts and pressure-sensitive adhesives have a tendency to attach to the surfaces of machinery during paper production and cause surface fouling. The focus of this thesis was on the mechanisms of sticking and surface fouling on a paper machine surfaces caused by problematic sticky organic materials. The sticking potential of six styrene–butadiene latices varying in carboxylation degree, crosslinking density and viscoelasticity and one polyacrylate pressure sensitive adhesive were studied using a cylindrical probe tack method under dry and aqueous conditions. Sticking potential was measured using low and high energy surfaces as an adherent. Also a new practical method for the on-site evaluation of nonstick properties of cylinder coating materials was developed. This method enables monitoring the condition of the coating during its life cycle and also provides the opportunity to compare the performance of different drying cylinder coating materials. The research performed clearly showed that low viscoelastic modulus of latex increases sticking tendency. The results also showed that presence of water can either increase or decrease adhesion depending on the moisture content ant the physic-chemical properties of sticky materials. A low surface energy coating strongly decreases sticking compared to a high energy surface and have a lower susceptibility to fouling in the dry environment. In aqueous conditions, the use of high-energy surfaces decreases adhesion of latices due to their strong interaction with water. Also, the results indicated that carboxylation decreases sticking potential of latex in both dry and aqueous environmentsTiivistelmä Paperikoneiden likaantuminen aiheuttaa suuria tuotannollisia menetyksiä johtuen tuotantoprosessin katkoksista ja paperin laadun ongelmista. Paperikoneen pintojen likaantuminen on monimutkainen prosessi, johon vaikuttavat monet toisistaan riippuvat tekijät ja siten likaantumisilmiötä on vaikea hallita. Paperin raaka-aineet voivat sisältää epäpuhtauksia, kuten vahoja, kuumasulate- ja tarraliimoja, jotka tarttuvat paperikoneen pintoihin aiheuttaen niiden likaantumista. Lisäksi paperin prosessiympäristö muuttuu märästä kuivaan valmistusprosessin edetessä ja lämpötilan kasvaa samanaikaisesti. Tässä väitöskirjassa on kuvattu paperikoneen pintojen likaantumisen mekanismeja ja erityisesti orgaanisten lika-aineiden tarttumista. Tutkimuksessa selvitettiin probe tack -menetelmää käyttäen kuuden erilaisen styreeni-butadieenilateksin ja polyakrylaattitarraliiman tarttuvuutta matalan ja korkean pintaenergian pinnoilla sekä kuivissa että märissä olosuhteissa. Työhön oli valittu latekseja, joiden karboksylointiaste, ristisilloitustiheys ja viskoelastiset ominaisuuden olivat erilaisia. Lisäksi väitöskirjatyössä kehitettiin paikan päällä suoritettava mittausmenetelmä paperikoneen kuivaussylinterien pinnoitteen puhtaana pysyvyyden määrittämiseksi. Tällä menetelmällä voidaan mitata pinnoitteiden kuntoa niiden elinkaaren aikana ja myös vertailla erilaisia pinnoitteita keskenään. Tutkimuksen tulokset osoittivat, että styreeni-butadieenilateksien matala kimmokerroin lisää niiden tarttumista paperikoneen pinnoille. Veden läsnäolo voi joko lisätä tai vähentää tarttumista riippuen veden määrästä ja lika-aineiden fysiokemiallisista ominaisuuksista. Myös paperikoneen pinnoitteen pintaenergia vaikuttaa tarttuvuuteen. Paperikoneen pinnoitteiden pieni pinta-energia vähentää tarttumista kuivissa olosuhteissa, kun taas korkean pintaenergian pinnoitteet vähentävät lateksien tarttuvuutta vesiolosuhteissa. Lisäksi lateksien karboksylointi vähentää niiden tarttumista sekä kuivissa että märissä olosuhteissa
2
Uusitalo, Angelica. "Optimization of circulating oil system for paper machine." Thesis, Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-86429.
Full textAbstract:
At the beginning of this project the goal was to create a concept for a brand new oil return system for the drying section of BillerudKorsnäs Karlsborgs paper machine. The goal was changed during the project in consultation with BillerudKorsnäs. The cause of that was a too uncertain system specification. The new goal was to create a correct and detailed system specification for the circulating oil system at the paper machine drying section. During the project all lubrication points where detected. The paper machine have a total total of 423 lubrication points in the dryer section, 400 bearing houses and 23 gearboxes. The current oil system is divided into two parts; one for the pre dryer and one for the post dryer. The current total flow of the system is approximately 884 l/min. Since the pilot study and need analysis showed that the bearings are not working during sufficient lubrication, a new required flow for each lubrication point was calculated. This showed that a new oil system would have a total flow of 1260 l/min to provide the bearings and gearboxes with the right amount of oil. The new oil system should also have a different division; one oil system for the bearings and one oil system for the gearboxes. All the results was summarized in a new system specification for a request of a new oil system for the paper machine. The current oil system also have large problems with water entering the system. This led to a second goal; suggest solutions to minimize water in the oil system. An identification of the possible position where water enters the oil system was done. This showed that water enters the system through the labyrinth seals in the bearing houses. The solution to minimize water in the oil system is following: Continue to test the new air intakes placed directly to the bearing houses together with installation of flash protection covers on the cylinder shaft. If this works the new air intakes will provide colder and dryer air to the system. This will reduce the air flow of hot humid air through the labyrinth seals.
3
Hashemi, Aghchehbody Seyed Jalaleddin. "Through drying of machine formed paper and drying nonuniformity." Thesis, McGill University, 1996. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=37702.
Full textAbstract:
Transport phenomena characteristics were determined for the through air drying of machine-produced printing and heavier papers. The momentum transport is strongly affected by the specifications of machine-formed papers, but of the drying rate characteristics only the critical moisture content varied between the types of paper tested. To determine the impact of individual parameters of commercial papermaking these experiments with machine-formed paper were supplemented by the use of handsheets. The papermaking parameters of beating, wet pressing, formation and pulp blending all strongly affect the momentum transport through the paper but only the quality of sheet formation and composition of TMP-kraft pulp blends influences drying rates measurably.The general phenomenon of nonuniformity in through drying was examined, including its association with nonuniformity of paper structure, with process conditions affecting drying nonuniformity, and implications for minimizing the cost of providing the flow of drying air through semi-permeable grades of paper. The development and decay of non-uniformity during drying was demonstrated through two techniques, one based on the measurement of local sheet moisture content, the other with continuous monitoring of the local air exhaust temperature from the sheet. Drying nonuniformity is quite sensitive to the quality of formation and to drying intensity, and is less severe at both the higher and lower end of the basis weight range. The biggest effect on drying nonuniformity is the improvement possible by reduction in the initial moisture content. In-plane moisture diffusivity was determined to be a very strong function of sheet moisture content, and is not fast enough to reduce the sheet moisture nonuniformity during drying.
The study provides guidance in the possible future use of through air drying for application to grades of paper heavier than those for which it is now used.
4
Shirt, Roger William. "Modelling and identification of paper machine wet end chemistry." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape17/PQDD_0017/NQ27246.pdf.
Full text
5
Svedberg, Anna. "Valuation of retention/formation relationships using a laboratory piot-paper machine." Licentiate thesis, KTH, Fibre and Polymer Technology, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4517.
Full textAbstract:
The interdependency between filler retention and paper formation is well-known, where a high retention is accompanied by impaired formation. A challenge for today’s papermakers is to increase the competitiveness for uncoated and coated fine paper, by improving the formation at the same level of retention.
Over the years, the use and the demands of retention aids have increased as a consequence of a higher system closure, increased machine speeds and increased filler content. The knowledge of whether some retention aid systems are more or less detrimental to paper formation than other systems, is very limited. The insuffiency of knowledge is, however, also true for other chemical, mechanical and interacting factors, which influence the retention/formation relationship in a complex manner.
In order to investigate the retention/formation relationship (features, retention aids, dosage points, etc.), a pilot-scale fourdrinier former (R/F-machine) has been developed. The R/F-machine provides a short circulation of the white water and controlled experimental conditions and is appropriate for cost-effective investigations. Moreover, the R/F-machine has been designed to have a short residence time to chemical equilibrium and the machine has also shown high reproducibility in the results.
This licentiate thesis presents the R/F-machine and examines, during constant experimental conditions, the retention/formation relationships for some different retention aid systems. Three single-component cationic polyacrylamides with varying molecular weights and two polyacrylamide-based microparticulate systems with varying microparticles were examined. The retention aid systems were investigated on the R/F-machine, for a fine paper stock (90 % bleached hardwood and 10 % bleached softwood) with addition of 25 % filler (based on total solids content).
The results showed that the retention/formation relationship was not dependent on the retention aid system used. All systems showed the same relationship between retention and formation. On the other hand, the various retention aid systems provided different effects considering their retention performance.
6
Nygårds, Erika. "Experimental equipment for simulation of press nip in tissue paper machine : Prestudy and concept generation." Thesis, Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kau:diva-44522.
Full textAbstract:
During manufacturing of tissue paper, large amounts of energy could be saved with an optimized press nip. In the press nip, water is pressed out of the paper and depending on both machine and paper parameters, the dewatering effect will vary. The dewatering process is however, a complex process which is not fully understood. With the facility to simulate different tissue machine concepts in a lab-testing machine, theoretical models of the dewatering process could be tested and evaluated. Karlstad university has started a three-year project with the purpose of building a lab-test equipment for simulation of pressing of paper, and one of their partners during this project is the company Valmet AB. This master thesis was a part of this three-year project and was carried out in collaboration with Valmet AB. The aim of the master thesis was to determine important parameters affecting the pressing process and the requirements to be considered during the design of the lab-test equipment. The goal was also to develop some concrete concept proposals. During the literature study it was found that the most important parameters of the equipment affecting the result were nip pressure, duration time and process temperature. Paper parameters with the biggest effect on the result were compressibility resistance, flow resistance, ingoing moisture and temperature stability. After discussion with the engineers at Valmet AB, customer requirements of the equipment were determined and these, in combination with the information gathered from the literature study, were used in order to determine the product requirements of the equipment. The most important product requirements turned out to be load capacity, changeable load, process time, distance between upper and lower plate and incorporation of load cells. Several different concept proposals were developed and four of them where evaluated further. The biggest challenge in designing a lab-test equipment for simulation of pressing of paper is the short duration time in combination with high loads, and therefore, all concepts were evaluated according to this as a first step. Plenty of work still needs to be done before any of the generated concepts are finished, but three of them, Three weight, Profile and Electromagnet are seen as potential solutions.Vid tillverkning av mjukpapper kan stora mängder energi sparas genom att optimera pressnypet. Detta då man i pressnypet kan avlägsna stora mängder vatten från pappret med hjälp av en presskraft, men beroende på både maskin- och pappersparameterar varierar avvattningsförmågan. Avvattningsförloppet är dock en mycket komplicerad process som ännu inte är helt förstådd. Med möjligheten att simulera olika maskinkoncept i en lab-testmaskin kan teoretiska modeller av avvattningsförloppet testas och utvärderas. Karlstads universitet har nyligen startat ett treårigt projekt med syfte att bygga en lab-testmaskin för pressning av papper och en av deras samarbetspartners är företaget Valmet AB. Detta examensarbete var en del av detta treåriga projekt och utfördes i samarbete med Valmet AB. Målet med examensarbetet var att bestämma vilka parametrar som påverkar avvattningen i pressnypet och vilka krav som måste beaktas under designen av lab-testmaskinen. Målet var även att ta fram konkreta konceptförslag. Från litteraturstudien framkom det att de parametrarna hos utrustningen vilka kommer påverka resultatet mest var nyptryck, varaktighet och processtemperatur. De pappersparametrar vilka har störst betydelse för resultatet visade sig vara kompressabilitetsmotstånd, flödesmotstånd, ingående fukthalt och temperaturstabilitet. Efter diskussion med ingenjörer på Valmet AB kunde kundkraven bestämmas, och dessa i kombination med den sammanställda informationen från litteraturstudien användes för att bestämma produktkraven för utrustningen. De viktigaste produktkraven visade sig vara lastkapaciteten, ändringsbar kraft, processtid, avstånd mellan övre- och nedre plattan, samt att lastceller ska vara inkluderade. Av alla de koncept som togs fram under genereringsarbetet, utvärderades fyra av dem. Den största utmaningen vid design av en lab-testutrustning för simulering av pressning av papper är den korta pressningstiden i kombination med den höga lasten, och därför prioriterades en utvärdering av koncepten utifrån dessa aspekter. Mycket arbete återstår innan ett färdigt koncept står klart, men tre av de utvärderade koncepten, Tre vikter, Profil och Elektromagnet, har potential till att utvecklas till realiserbara utrustningar som möter de uppsatta kraven.
7
Steele, Joseph Ronald. "Optimizing mixing in the dilution system of a paper machine." Thesis, Georgia Institute of Technology, 2010. http://hdl.handle.net/1853/33887.
Full textAbstract:
In the flow distribution section of a paper machine, known as the head box, water is injected into the fiber suspension (stock) flow through a tee-mixer for more uniform production. This dilution process has two important requirements that must be fulfilled: (1) sufficient mixing so that the dilution flow spreads across the suspension flow and (2) that the injection flow rate not be so large to significantly alter the local head box flow rate. The objective of this research was to find a combination of velocity ratio and tee mixer geometry that lead to the injection flow being well mixed into the stock flow, but at the same time, the injection should not cause the total flow rate to change by more than 1%. Velocity ratios of 0.25, 0.75, 1.33, 1.5 and 2.25 were examined for four different cases of tee mixer geometries using the CFD software Fluent. Two of the cases had added contractions located near the injection point, while the other two cases had a more standard geometry with no added complexities. The pressure drop across the injection point was also measured. Mixing was qualitatively measured by simulating the injection of a passive tracer into the dilution flow. All of the results indicated that the case where the contraction was located after the injection showed the most promising results with quality mixing and lower flow rates. The cases without added contractions showed poor mixing for lower velocity ratios, and for higher velocity ratios, the flow rates were too large. The cases with contractions showed similar mixing, but the outlet flow rates produced were lower when the contraction was located after the injection instead of before it. A velocity ratio of 0.25-0.75 for the mixers with contractions produced acceptable flow rates and sufficient mixing. The simulations also showed that the static pressure for the contraction cases were nearly identical throughout the majority of the pipe. For both contraction cases the pressure drop across the injection increased with increasing injection flow rate. When the contraction was located before the injection, a pressure drop of 16% was calculated. A pressure drop of 18% to 20% across the injection resulted when the contraction was located after the injection.
8
Laitinen, Tarja. "Thiosulfate pitting corrosion of stainless steels in paper machine environment /." Espoo, Finland : VTT, Technical Research Centre of Finland, 1999. http://www.vtt.fi/inf/pdf/publications/1999/P399.pdf.
Full text
9
Zhou, Lily M. Eng Massachusetts Institute of Technology. "Paper Dreams : an adaptive drawing canvas supported by machine learning." Thesis, Massachusetts Institute of Technology, 2019. https://hdl.handle.net/1721.1/122990.
Full textAbstract:
This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.Thesis: M. Eng., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 2019
Cataloged from student-submitted PDF version of thesis.
Includes bibliographical references (pages 55-58).
Despite numerous recent advances in the field of deep learning for artistic purposes, the integration of these state-of-the-art machine learning tools into applications for drawing and visual expression has been an underexplored field. Bridging this gap has the potential to empower a large subset of the population, from children to the elderly, with a new medium to represent and visualize their ideas. Paper Dreams is a web-based canvas for sketching and storyboarding, with a multimodal user interface integrated with a variety of machine learning models. By using sketch recognition, style transfer, and natural language processing, the system can contextualize what the user is drawing; it then can color the sketch appropriately, suggest related objects for the user to draw, and allow the user to pull from a database of related images to add onto the canvas. Furthermore, the user can influence the output of the models via a serendipity dial that affects how "wacky" the system's outputs are. By processing a variety of multimodal inputs and automating artistic processes, Paper Dreams becomes an efficient tool for quickly generating vibrant and complex artistic scenes.
by Lily Zhou.
M. Eng.
M.Eng. Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science
10
Yousefi, Mahdi. "Performance assessment and online input design for closed-loop identification of machine directional properties on paper machines." Thesis, University of British Columbia, 2014. http://hdl.handle.net/2429/50053.
Full textAbstract:
Model-based controllers based on incorrect estimates of the true plant behaviour can be expected to perform badly. Due to the fact that machine directional proper- ties in paper machines can be controlled by model predictive control, it is important for us to use a valid model of the process in the controller to keep controller per- formance high. Performance is measured to detect model-plant mismatch using a minimum variance index and a closely related user-specified criterion. In this the- sis, we define a sensitivity measure that relates system performance to model-plant mismatch, and use it to explore this sensitivity for three realistic types of paramet- ric modelling errors. This analysis shows the power of the indices to detect model plant mismatch. In addition, the effect of model-plant mismatch on the closed loop behaviour is discussed.
To compensate controller performance in the case of model-plant mismatch, the process needs to be re-identified to update the process model. This thesis presents a new approach to input design for closed loop identification. The idea is to maximize the trace of the Fisher information matrix associated with the plant model in a moving horizon framework, while enforcing explicit constraints on both inputs and outputs. The result is the richest possible excitation signal for which the operation of a running closed-loop system remains within acceptable bounds. The method can be combined with a fixed model variable regressor technique to esti- mate time delays.
The suggested technique is implemented and used to monitor performance of machine-directional processes in an industrial paper machine and identify the pro- cess if any degradation in controller performance because of model-plant mismatch is detected.Applied Science, Faculty of
Electrical and Computer Engineering, Department of
Graduate
11
Jortama, T. (Timo). "A self-assessment based method for post-completion audits in paper production line investment projects." Doctoral thesis, University of Oulu, 2006. http://urn.fi/urn:isbn:9514281241.
Full textAbstract:
Abstract
The aim of this technologically oriented study was to develop an evaluation method for post-completion audits of investment projects in paper production lines. The development work was based on the constructive research approach. The objectives of the method were practical applicability, a comprehensive framework, and measures of project performance.
The evaluation method developed here is based on an adapted Malcolm Baldrige self-assessment framework, which has been embedded with three evaluation perspectives: project Targets (T), Risk management (R), and company Strategy (S). The compositions of these perspectives i.e. TRS perspectives, serve as the fundamental basis for a value added project. The evaluation criteria have been designed to fulfil the requirements of the paper industry and demanding projects. Scoring guidelines are used as a basis for evaluation results. Furthermore, supportive evaluation tools were developed to improve the accuracy and comparability of evaluation results. Evaluation is conducted by a group which consists of qualified tutors, project experts and facilitators. The latter are used especially to increase objectivity.
The method was tested with two cases studies which were applied in a greenfield paper machine project. The first case study focused on technology choices. The second case study was a full-scale study of the whole project scope. The evaluation results were relatively accurate, and feedback results were particularly positive.
Usage of the TRS perspectives can produce information which benefits decision-making. The method is capable of measuring both technical facts and subjective opinions. Moreover, the method is applicable in practice and can improve the investment process in general.
12
Domingo, Garth Selby. "UF membranes operated on paper machine wastewater : fouling tendencies and characterisation." Thesis, Stellenbosch : Stellenbosch University, 2001. http://hdl.handle.net/10019.1/52595.
Full textAbstract:
Thesis (MSc)--Stellenbosch University, 2001.ENGLISH ABSTRACT: At the Mondi Kraft paper mill in Piet Retief, paper machine effluent is pre-treated by means of dissolved air flotation (DAF) and a mierostrainer prior to ultrafiltration (UF). Despite the rigorous pre-treatment of the effluent, severe fouling of the UF membranes still persisted, resulting in a sharp decrease in operational flux. In an attempt to improve the flux performance of the UF membranes an investigation was launched into the possible causes of membrane fouling. The study yielded the following results: Ultraviolet-visible (UV-Vis) spectrophotometric analyses of varIOUS effluent samples collected from different locations at the mill indicated the presence of aromatic compounds. Lignosulphonate appeared to be the main constituent in all the samples analysed. UV-Vis spectrophotometry was also performed on fouling extracted from membranes In order to evaluate the different approaches attempted to reduce membrane fouling. Most of the UV-Vis spectra obtained did not show the absorbance maxima below 210 nm that were seen for the paper machine effluent, DAF product, lignosulphonate and mierostrainer product. This indicated that the compounds with absorbance at lower wavelengths did not foul the membranes to the same extent as the aromatic substances with absorbance maxima between 230 and 400 nm. The influence of pH on the absorption of the various effluent samples was also investigated. An increase in pH resulted in (1) a "shift" in the wavelength scans from a lower to a higher wavelength, suggesting ionisation (deprotonation) with a subsequent delocalization of electrons and (2) an increase in the turbidity. The increase in turbidity which accompanied the Increase in pH could be explained by complex formation between the carboxylate ions, phenolic groups and divalent metal ions present in the effluent. Inductively coupled plasma analyses of several effluent samples with pH values 7 and 13 indicated the presence of significant amounts of Ca2+ ions in the effluent. There was a significant decrease in the Ca2+ levels with an increase in pH, which supported the hypothesis that Ca2+ might contribute to complex formation. This resulted in a decrease in solubility and an increase in turbidity. The addition of a chelating agent (ethylenediaminetetra-acetic acid disodium salt) to an effluent solution at pH 13 redissolved the precipitate and considerably reduced the turbidity. The subsequent addition of CaCh again induced precipitation and increased turbidity, confirming the role of Ca2+ in complex formation. Gel permeation chromatographic analyses of mierostrainer product at pH 13 showed the formation of high molecular mass organo-calcium complexes. The exact molecular mass of the complexes present in the mierostrainer product could not be determined by electro spray mass spectrometry because of their poor ionisation ability. Atomic force microscopy and scanning electron microscopy (SEM) showed distinct differences in the membrane surface texture before and after fouling. Furthermore, SEM images of the UF membranes exposed the limited ability of the 30 urn microstrainer, installed downstream from the DAF unit, to remove residual fibres from the DAF product. Static fouling experiments performed on all the flocculants and coagulants used In the paper-making process at the mill showed that none of these substances fouled the UF membranes. Cleaning of the UF membranes with Triton XIOO®, a nOn-IOnIC surfactant, caused a temporary increase in the operating flux to values higher than that of the initial flux. Mechanical cleaning of the UF membrane surface with spongebalIs proved to be one of the most effective and successful methods to prevent flux loss caused by fouling. Pre-coating of the UF membranes with Plutonic" FI08, another non-ionic surfactant, did not promote membrane productivity. Evaluation of various types of membranes indicated that hydrophilic or negatively charged membranes withstood membrane fouling more effectively than hydrophobic UF membranes under the same operating conditions.
AFRIKAANSE OPSOMMING: By Mondi Kraft se papier meule in Piet Retief word afloopwater vanaf die papiermasjiene vir hergebruik met behulp van ultrafiltrasie (UF) behandel. Opgeloste lugflotasie (OLF) en mikrosiwwing word as voorbehandeling vir die UF membraanproses ingespan. Ondanks die intensiewe voorafbehandeling wat toegepas word, vind daar geweldige aanvuiling van die UF membrane plaas wat tot die vinnige verlaging in bedryfsfluks aanleiding gee. 'n Ondersoek na die moontlike oorsake van membraan-aanvuiling het die volgende bevindinge opgelewer: Ultraviolet-sigbare (UV-Vis) spektroskopie van water monsters wat by die meule versamel is, het die teenwoordigheid van aromatiese komponente aangetoon, met lignosulfonaat die hoofkomponent in al die monsters wat ontleed is. Ekstrakte afkomstig van aangevuilde membrane is ook met behulp van UV-Vis-spektroskopie geanaliseer om verskeie benaderings te evalueer om 'n afname in membraan-aanvuiling te bewerkstellig. Die oorgrootte meerderheid spektra het nie die absorpsie maksima onder 210 nm aangetoon wat teenwoordig was in monsters van die papier masjien afloopwater, OLF uitvloeisel, lignosulfonaat en mikrosif produkwater nie. Dit het aangedui dat die komponente wat by laer golflengte absorbeer nie die UF membrane in dieselfde mate aanvuil as daardie komponente wat by hoër golflengtes (tussen 230 en 400 nm) absorbeer nie. Die invloed wat pH op die absorpsie van komponente teenwoordig in die onderskeie afloopwatermonsters het, is ook ondersoek. 'n Toename in pH het bygedra tot (1) 'n verskuiwing in die spektra vanaf 'n lae na 'n hoër golflengte vanweë ionisasie (deprotonering) met gevolglike delokalisasie van elektrone en (2) 'n toename in turbiditeit. Die toename in turbiditeit wat verband hou met die toename in pH was verduidelik aan die hand van kompleksvorming tussen die karboksilaat ione, fenoliese groepe en divalente metaal ione in die afloopwater. Induktief gekoppelde plasma analise van verskeie water monsters by pH 7 en 13 het die teenwoordigheid van 'n groot hoeveelheid Ca2+ aangetoon. 'n Verlaging in die vlakke van opgeloste Ca2+ het met die toename in pH verband gehou. Dit het die moontlike verbintenis tussen Ca2+ en kompleksvorming ondersteun wat bygedra het tot die afname in oplosbaarheid en toename in turbiditeit. Die byvoeging van etileendiamientetra-asynsuur-dinatriumsout, 'n kelerings reagens by afloopwater (pH 13) het die presipitaat weer in oplossing gebring en die turbiditeit merkwaardig verlaag. Die byvoeging van CaCh het weer presipitasie geïnduseer, met 'n gevolglike toename in turbiditeit. Hiermee is Ca2+ se rol in kompleksvorming bevestig. Gelpermeasie-chromatografiese analise van die mikrosif produk (pH 13) het die vorming van hoë molekulêre massa organo-kalsium komplekse bevestig. Dit was egter nie moontlik om met behulp van massaspektrometrie die korrekte molekulêre massa van die komplekse te bepaal nie vanweë hul onvermoë om te ioniseer. Atomiese krag mikroskopie en skandeer elektron mikroskopie (SEM) het duidelik die voor en na verskil getoon wat aanvuiling op die membraantekstuur gehad het. 'n SEM foto van die aangevuilde UF membraan het die onvermoë van die mikrosif blootgelê om oorblywende vesels vanuit die OLF produkwater te verwyder. Resultate bekom gedurende passiewe aanvuilingseksperimente het aangetoon dat al die in-proses flokkulante en koagulante wat gebruik word by die papier meule geen bydrae tot die aanvuiling van die UF membrane maak nie. Skoonmaak van die UF membrane met Triton XIOO® bring 'n verhoging in bedryfsvloed teweeg, maar die verhoging, wat hoër as die oorspronklike vloed is, is kortstondig. Meganiese skoonmaak van die buismembrane met behulp van sponsballe blyk die mees effektiewe skoonmaakmetode te wees. Voorafbehandeling van die UF membrane met Plutonic" F 108 het nie die membraanproduktiwiteit verhoog nie. Daar is ook bevind dat hidrofiliese of negatief gelaaide membrane groter weerstand bied teen aanvuiling in vergelyking met hidrofobiese UF membrane onder dieselfde bedryfstoestande.
13
Lindqvist, Anders N. "Structures in the flow from paper machine headboxes : a model study." Licentiate thesis, Luleå tekniska universitet, 1996. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-26745.
Full text
14
Hoffman, David William. "Bursting strength control on a linerboard machine." Thesis, McGill University, 1985. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=63326.
Full text
15
Andersson, Mattias, and Anders Berneke. "Basis and a concept for a Paper machine in a laboratory scale." Thesis, Örebro universitet, Institutionen för naturvetenskap och teknik, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:oru:diva-27626.
Full textAbstract:
This thesis studies paper and what it is made of and different ways to manufacture it in a laboratory scale. It also contains a comparison of different ways to dry tissue and which method that suits a small laboratory tissue machine best. A small paper machine was found at Metso in Karlstad that was used as a basis for the concept machine. Since the machine at Karlstad used pressing and a cylinder drying method that involves pressing an alternative method to dry the paper had to be chosen. For drying tissue there are several methods like, infrared and through air drying. A comparison was made between those methods to find out which suited the specification best. The comparison shows that through air drying is the best drying method for the machine.I detta examensarbete studeras hur man tillverkar papper och olika sätt att tillverka papper i laboratorium skala. Den innehåller också en jämförelse av olika sätt att torka papper och vilken metod som passar bäst till en liten pappersmaskin. En liten pappersmaskin hittades vid Metso i Karlstad. Den användes som grund för vårt förslag till maskin. Eftersom maskinen i Karlstad använde ett pressparti och flera torkcylindrar till att torka arket så behövdes de bytas ut. En jämförelse mellan olika torkmetoder gjordes för att finna en ny lämplig metod för ändamålet. Litteraturstudien visar att det finns flera torkmetoder så som infraröd torkning och genomblåstorkning. En jämförelse gjordes mellan dessa metoder för att ta reda på vilken passade specifikationen bäst. Jämförelsen visar att genomblåstorkning är det bäst lämpade metoden för maskinen.
16
Stewart, Gregory Edward. "Two dimensional loop shaping controller design for paper machine cross-directional processes." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape4/PQDD_0015/NQ56628.pdf.
Full text
17
Gerardi, Marcelin, and Miki Namsrai. "A software system for variables comparison of a paper machine for improved performance." Thesis, Högskolan Dalarna, Energiteknik, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:du-28781.
Full textAbstract:
Today paper is to find everywhere, and the production factories always need to increase the productivity if they want to stay competitive. Stora Enso Kvarnsveden has one of the biggest magazine paper machines in the world, which produces around 1900 meters of paper per minute. The production process is highly automatized, which reduces the number of operators that work on the machine. Still, process variations can cause brakes in the paper web and lead to loss of income, energy and paper production. It may also have a direct impact on the paper quality. This report is focusing the following question: How to keep the Paper Machine production process under controlled conditions? To make a data analysis fully relevant, we need to use the most important variables of the machine. By analyzing these data some unexpected behavior and variation of process values can be pointed out. The analyzing tool needs to be fast and portable, and therefore a software system has been developed. By comparing process data with reference data this software can make a powerful analysis. The created software is intended to be used either by operators or engineers. The most important results are collected in a file. In this text file, the comparison function gives the results which are stored in a CSV-format. Furthermore, an auto-update function allows the users to run it automatically. Graphical presentations are supporting the interpretation of the results.
18
Gilfoil, Wyly. "Smart Water Receiver for Use in the Wet Press Section of a Paper Machine." Thesis, Georgia Institute of Technology, 2005. http://hdl.handle.net/1853/7117.
Full textAbstract:
When the paper web and press felt enter a nip in the press section of a paper machine, both the paper web and felt are compressed. Water is forced from the paper sheet into the press felt due to a hydrodynamic pressure gradient between the sheet and felt. Water not only flows through the felt in the transversal z-direction, but also flows through the felt in the machine and cross-machine directions.
On the exit side of the nip, the pressure imposed on the sheet-felt system by the rolls begins to decrease. Both the paper web and press felt begin to expand, and a vacuum is created in the web and felt. The vacuum in the web is stronger than that in the felt, and thus water and air tend to flow from the felt back into the sheet, causing rewet. Three mechanisms that contribute to rewet have been proposed: 1) film splitting between the paper web and press felt, 2) capillary forces in the web drawing water from the felt into the web, and 3) the pressure differential between the web and felt during expansion.
The objective of this project was to design and test under flow conditions similar to those in a press nip a smart water receiver to be used in the press section of a paper machine. In this manner, the feasibility of such a water receiver was to be determined. The purpose of this water receiver is to accept water that is pressed from the paper web in a nip and prevent the return of this water to the paper web upon exit from the nip. Thus, the smart water receiver allows flow through the felt in the positive z-direction of the felt (away from the paper web) and not in the negative z-direction (towards the paper web). The smart water receiver concept utilizes a layer of micro-check valves incorporated into the press felt to perform in the desired manner. A mathematical model and lab-scale prototype were created in order to predict the behavior of such a design in the press nip.
19
Gaillemard, Christelle. "Modelling the Moisture Content of Multi-Ply Paperboard in the Paper Machine Drying Section." Licentiate thesis, Stockholm : Department of Mathematics, Royal Institute of Technology, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-3903.
Full text
20
Haapala, A. (Antti). "Paper machine white water treatment in channel flow:integration of passive deaeration and selective flotation." Doctoral thesis, Oulun yliopisto, 2010. http://urn.fi/urn:isbn:9789514263682.
Full textAbstract:
Abstract
Gas removal from the papermaking process is currently a standard practice, whereas purification of the internal water circulation has become common only recently. Both unit processes have progressed greatly during recent decades and new concepts are constantly being developed. The aim of this thesis was to analyse the efficiency and applicability of a channel flow design introduced by Metso for passive white water deaeration and to study the dynamics of passive bubbly gas removal. In addition, separation of the detrimental process water components by selective flotation during deaeration was studied to add further functionality to the channel flow design.
Turbulent mixing at the flow discharge and the consequent air entrainment were seen to limit the gas separation efficiency. Also, the properties of different white waters notably affect their deaeration through viscous forces, the concentration of surface active components and bubble-particle interactions. Thus similar levels of gas separation cannot be achieved with all process waters. The analysis showed that the drag of small microbubbles is mostly caused by hydrophobic contamination and the dispersed particles that readily attach to the bubbles. Correlations were derived based on experimental data to provide new information on the drag force experienced by small bubbles in white waters.
Chemically unaided flotation of white water in the channel flow was shown to be efficient in separating hydrophobic contaminants that have adverse effects on paper machine production and product quality. Both good reductions in contaminant content and high selectivity in their removal were achieved. Channel flow with an overflow can be considered well suited for the first stage of froth separation, while further treatment of the channel flow reject may consist of a secondary flotation or other process that enables the recirculation of fines and fillers. Although a certain level of losses of fines and fillers must be expected, substantial fraction of these solid components can be returned to the process stream.
The proposed multifunctional process, channel flow deaeration and frothing of white water, was seen to be straightforward, economical and feasible while also providing benefits in terms of total process efficiency that are not delivered by any current process scheme. The experimental parameters presented here regarding bubble dynamics and flotation efficiency can be used to achieve better models of these processes.
21
Lepp, Gary. "A numerical investigation of the pressure distribution on a Fourdrinier paper machine drainage foil." Thesis, University of British Columbia, 1986. http://hdl.handle.net/2429/26307.
Full textAbstract:
A mathematical model and three numerical solution procedures have been developed to predict the pressure distribution on a Fourdrinier paper machine drainage foil. The present models are based on a numerical solution of the full laminar boundary layer equations. Previous modelling attempts have made use of the boundary layer equations in various simplified forms. The solution procedures used were grouped into two categories; the one-dimensional models and the two-dimensional model. The one-dimensional models were based on an approximate integral solution of the boundary layer equations. The two-dimensional model was based on a solution of the boundary layer equations using a finite difference method.
Experimental measurements of the pressure distributions and the drainage rates on three tapered foils and two stepped foils were made to provide data for comparison with the results of the models. Computed results obtained using the solution procedures generally did not agree well with the experimental results of the present investigation. The results, however, did predict observed trends in the pressure distributions due to variations in the wire velocity and foil geometries. Consequently, the models may be considered viable approaches to predicting the pressure distribution on a foil, though a great deal of further work is necessary before the solution procedures may be used for design purposes.Applied Science, Faculty of
Mechanical Engineering, Department of
Graduate
22
Valeri, Nicolò. "Virtual Commissioning of a sorting system of an automatic machine for paper roll packaging." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2021.
Find full textAbstract:
What is happening nowadays is, in all respects, a great industrial revolution, which has radically changed the manufacturing industry sector. The complexity of modern production plants is constantly growing, and the continuous technological progress places an enormous effort on the shoulders of manufacturers to satisfy the requirements set by an increasingly competitive market. Today the validation and testing of an automation system is a demanding task, usually performed in very tight deadlines. Therefore, the use of simulations to verify the automation system early in the design phase can be very beneficial. In this context, technologies such as Digital Twin or Virtual Commissioning come into play, both of which have, at the base, the idea of building and exploiting a completely digital replica of a real system.
Virtual Commissioning allows to test the control software of a real machine on a virtual model, or a Digital Twin, in a risk-free environment. This allows to have an early software debug and to reduce possible errors as well as reduce the commissioning time of a machine. The thesis work deals with the Virtual Commissioning of a sorter system at the entrance to an automatic machine for packaging paper rolls, in order to test the control software and evaluate its performance. From this work it is possible to understand which are the steps and the necessary tools for the realization of the virtual commissioning of an automatic machine. It immediately emerges how effective it is to work through simulations on a virtual model of the machine rather than on the real machine. Finally, the future possibilities of virtual commissioning of the entire automatic machine are discussed.
23
Uusi-Tarkka, Eija Katariina. "Bio-based nonwoven fabric-like materials produced by paper machines." Thesis, Högskolan i Borås, Akademin för textil, teknik och ekonomi, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:hb:diva-10690.
Full textAbstract:
The purpose of this thesis is, in collaboration with the Swedish company Innventia, to explore the possibilities of using paper machines to create fabric-like nonwoven materials. As part of a relatively new research-area, it serves as some of the ground knowledge that is needed to drive this field forward. The research of this thesis is born from the increasing need for more environmental friendly textiles, and to find new uses for the paper production facilities and companies that are currently experiencing a decline in paper production. The materials used in the research were produced with the Finnish handsheet former and the StratEx sheet-maker made by Innventia. The research consists of the following tests: Tissue Softness Analysis, (TSA), tensile strength and bending stiffness. The tests are done with different combinations of lyocell, PLA, softwood and dissolving pulp in the tested sheets. It is also tested if the lyocell can be a meaningful substitution for PLA in combination with softwood pulp and dissolving pulp when creating the fabric-like materials. In conclusion of this research it can be said that, compared to benchmarking samples like bedding sheets, table cloths and cotton shirts, the sheets created and tested are competitive alternatives to existing materials when it comes to softness. It also became clear that the tensile strength has to be increased to make fabric-like nonwoven materials applicable on the same level as existing textiles. Even so, it is still evident that there is a potentiality in the use of paper machines in the development and creation of new fabric-like materials.
24
Sjöstrand, Björn. "Dewatering aspects at the forming section of the paper machine : Rewetting and forming fabric structure." Licentiate thesis, Karlstads universitet, Institutionen för ingenjörs- och kemivetenskaper (from 2013), 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kau:diva-47640.
Full textAbstract:
The underlying motives of the research undertaken here are twofold: to obtain a deeper understanding of the dewatering mechanisms at the forming section of a papermaking machine and to develop numerical models that describe the flow through forming fabrics. More comprehensive knowledge of dewatering in the forming section allows suggestions to be made for improvements that reduce the amount of energy used in the process without affecting the quality of the end product. The objective of this thesis is to answer the following questions: How and why does rewetting occur at the high vacuum suction boxes? How does the structure of the forming fabric affect dewatering at the forming section? Is it possible to create accurate numerical models for forming fabrics, and can these be used to predict the dewatering behaviour of new types of fabrics? Laboratory and pilot studies simulating high vacuum suction boxes were performed together with numerical modelling of the flow of air and water through both the forming fabric and the paper sheet. The conclusion drawn from the pilot study is that rewetting significantly lowers the dryness of the paper sheet exiting the suction boxes. The phenomenon is extremely rapid and is most likely driven by capillary forces. The high speed at which this rewetting occurs makes it difficult to impede by placing the suction boxes closer to the couch pick-up: the solution is more likely to be the use of new and improved designs of the forming fabric. The structure of the forming fabric has been shown to affect the dewatering rate at certain conditions of vacuum dewatering, and can possibly be connected partly to the fact that fibres penetrate the surface of the fabric to varying degrees and partly to the flow resistance of the different fabric structures. Numerical models of high accuracy can be constructed and used to predetermine how new fabric designs would affect dewatering at the forming section. This thesis quantifies aspects of dewatering such as rewetting and the influence of the forming fabric. Understanding these dewatering aspects further provides for the potential enhancement of energy efficiency in the forming section, and thereby the entire papermaking process. The forming fabric can play an important role in improving energy efficiency: rewetting after the high vacuum suction boxes occurs more rapidly than was previously known, so its design might be the only possible way of impeding it. The forming fabric can also improve the rate of dewatering: it is therefore likely that its design will be important in the next stage of developing energy efficiency and thereby play a part in achieving a more sustainable future.This thesis quantifies aspects of dewatering such as rewetting and the influence of the forming fabric. Understanding these dewatering aspects further provides for the potential enhancement of energy efficiency in the forming section, and thereby the entire papermaking process. The forming fabric can play an important role in improving energy efficiency: rewetting after the high vacuum suction boxes occurs more rapidly than was previously known, so its design might be the only possible way of impeding it. The forming fabric can also improve the rate of dewatering: it is therefore likely that its design will be important in the next stage of developing energy efficiency and thereby play a part in achieving a more sustainable future.
25
Gune, Nandakumar Vithal. "Fluid mechanics of impingement region in an experimental simulation of a twin-wire paper machine." Thesis, University of British Columbia, 1985. http://hdl.handle.net/2429/27102.
Full textAbstract:
An experiment with impinging jet flows in narrow channels having moving walls was carried out. The channel was formed by placing two counter-rotating cylinders near each other. This geometry represents a simplified case of the impingement zone of a formation wedge on a twin-wire paper machine.
The variables considered in this study were jet velocity, roll velocity, jet width and, roll gap. The working fluid was water.
Wall shear stress signals and wall static pressure signals through the flow zone were recorded using signal recovery and averaging techniques. Flow velocity at a location below the mid-nip was measured using hot film anemometry from which mean velocity at the mid-nip was deduced. Flow visualisation experiments were also conducted. A very short duration synchronised flash (synchronised with roll rotation) was used to take the flow pictures.
It was observed that under certain conditions the impinging jet loses its momentum as it encounters an adverse pressure gradient in the flow zone. This results in a reversal of flow leading to a pond development above the nip. A relation has been obtained which sets conditions of roll speed, jet speed, jet width and roll gap under which stable operation (no backflow) can be achieved.
Flow pictures showed the presence of large quantities of entrained air. Entrained air was seen to pass through the flow zone as columns of air bubbles when the jet velocity was higher than the roll velocity. For jet velocity less than roll velocity, the passage of entrained air through the flow zone resulted in formation of rows of air bubbles.
Wall static pressure measurements revealed development of large positive pressures and pressure gradients in the impingement region. The pressure build up was believed to be due to loss of kinetic energy of the impinging jet, interaction of the wall boundary layers on either wall with flow in the core region (boundary layer interaction) and, reduction of cross sectional area of the flow geometry.
Wall shear stress levels were lower than pressure levels encountered in the flow. Hence it was concluded that the flow is mainly a pressure driven type, and that the shear stress values show variation of velocity gradients and subsequently velocity of the flow as affected by pressure changes.
A flow model is proposed to explain the reversal of flow leading to pond development. Relevance of this study to the analysis of a formation wedge of a twin-wire paper machine is explained. The study indicates that fluid mechanics of such a formation wedge should strongly affect the formation of paper web and machine runnability. The formation of streaks and machine direction basis weight variation observed in industrial situations may possibly be explained by the observed entrained air passage through the experimental flow nip.Applied Science, Faculty of
Chemical and Biological Engineering, Department of
Graduate
26
Berg, Jonathan. "Further development of manufacturing method for polyurethane shoe press." Thesis, Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:kau:diva-86081.
Full textAbstract:
The press-section of a paper machine holds several different types of press rolls. One of the many press roll variants is the Valmet produced press roll, ViscoNip. This press roll utilizes an extended nip in order to increase the amount of water removed. The extended press nip in ViscoNip is special since it is controllable by a pressurized polyurethane press shoe. The press shoe runs through the body of the press roll. Due to the limits of the current production process, new manufacturing methods and construction solutions are needed. In cooperation with another thesis, the current design and manufacturing process was reviewed and a plan intended to improve the current solution was formulated. The plan was to, by working together in a project, perform a product development process intended to create concepts able to utilize new methods of manufacturing. By using established methods of concept generation, such as Brainwriting 6-3-5, 11 concepts were created. Some of these concepts involved a redesign of the press shoe, leading to a need for construction and performance analysis. The other thesis focusing on the structural and mechanical performance evaluation of the new concepts. The work of this thesis focusing on researching new possible and available manufacturing solutions. The new concepts were analyzed with new and possible manufacturing methods to fulfill all the requirements. With all data, a document was created and market research was made to get feedback from more knowledgeable in the subject. Moreover, sequence analysis between the concepts with the current and those new manufacturing methods was made to further explain which manufacturing method that could solve the main problem. All in all, one different redesigned concept was deemed as having potential for further development. The current solution was also deemed as having potential for future development but only when new manufacturing methods or techniques were considered.
27
Cho, Byoung-Uk 1969. "Dynamics and control of retention and formation on a paper machine using a microparticulate retention aid system." Thesis, McGill University, 2005. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=85896.
Full textAbstract:
Control strategies for retention and formation processes are developed in order to stabilize the wet end operation and to reduce variations in the machine direction properties of paper without deteriorating formation of paper. The papermaking process using a microparticulate retention aid system is focused.The main factors affecting retention and formation were investigated with a CPAM (cationic polyacrylamide)/bentonite retention aid system and on a Fourdrinier pilot paper machine. The deposition efficiency model and the bridging strength model were developed to express the effects of the dosages of microparticulate retention aids on retention and paper formation, respectively. Effects of the pulp mass flow and the filler addition on first-pass retention and formation are also discussed.
Dynamic models of a retention process of a paper machine were developed from first-principles (mass balances). To describe the wet end chemistry effect, first-pass retention was included into the model as a parameter dependent on operating conditions. In addition, it was attempted to simulate dynamics of formation by developing an empirical model of formation and coupled with the dynamic models for the retention process. Transfer functions were derived from the models. It was found that the two major factors affecting the dynamics of the retention process are the first-pass retention of solids and the parameters related to the white water circulation such as the volume of the wire pit and the residence time at the wire pit.
Several control strategies were studied through simulation. The study showed that controlling the pulp mass and the filler mass in paper instead of basis weight and paper ash content can reduce the interactions without using decouplers. To reduce the variations in formation, the headbox pulp consistency control and the ratio control of a microparticle flow to a polymer flow are suggested. The problem concerning the set-points of white water consistency during grade changes was solved. Multivariable control of basis weight, ash content, white water consistency and headbox pulp consistency is also discussed.
28
Bergström, Mikael. "Product Development and Finite Element Analysis of Polyurethane Press Shoe : Produktutveckling och finit element analys av press-sko i polyuretan." Thesis, Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:kau:diva-85657.
Full textAbstract:
The press-section of a paper machine holds several different types of press rolls. One of the many press roll variants is the Valmet produced press roll, ViscoNip. This press roll utilizes an extended nip in order to increase the amount of water removed. The extended press nip in ViscoNip is special since it is controllable by a pressurized polyurethane press shoe. The press shoe runs through the body of the press roll. Due to limits of the current production process, new manufacturing methods and construction solutions are needed. In cooperation with another thesis, the current design and manufacturing process was reviewed and a plan intended to improve the current solution was formulated. The plan was to, by working together in a project, perform a product development process intended to create concepts able to utilize new methods of manufacturing. By using established methods of concept generation, such as Brainwriting 6-3-5, 11 concepts were created. Some of these concepts involved a redesign of the press shoe, leading to a need for construction and performance analysis. With the other thesis focusing on researching new possible and available manufacturing solutions. The work of this thesis fully committed to the structural and mechanical performance evaluation of the new concepts. This was performed by creating a model of the technical application using Finite Element Modelling in ABAQUS. The model included a hyperelastic material model for the polyurethane material as well as cohesive zone modelling to account for partitioning of the part. The model was then used to simulate the different concepts as they were subjected to a challenging load case. The results of which were used as the basis for structural and performance analysis. The analysis showed proof of sufficient structural stability and mechanical performance for all evaluated concepts. Then, in cooperation with the other thesis, a final concept choice was made. All in all, three different redesigned concepts were deemed as having potential for further development. The current solution was also deemed as having potential for future development but only when new manufacturing methods or techniques were considered.
29
Karlsson, Sanne. "Avsättningar i pappersmaskiner : Utbildning och förslag till processförbättringar." Thesis, KTH, Skolan för teknikvetenskaplig kommunikation och lärande (ECE), 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-154998.
Full textAbstract:
Deposits can be formed in the paper machine due to sticky materials from wood and recycled paper. These deposits get stuck on process equipment and cause the product quality to deteriorate and the efficiency of the paper machine is reduced. The purpose of this thesis is to increase the understanding about deposits among machine operators, and to suggest methods that can be used to reduce the amount of deposits formed in Bravikens paper machines. To fulfill the purpose of the thesis a pre-study, a literature review and interviews with machine operators and production staff, were carried out. These methods led to the planning and creation of an education about deposits for machine operators. The education about deposits for machine operators consisted of an interactive lecture to introduce the subject of deposits and a subsequent discussion. This approach was chosen to give the machine operators the opportunity to discuss their work situation on the paper machines related to their new knowledge about deposits. The education was carried out with hopes of finding new ways to manage the formation of deposits in the paper machines. According to the evaluation of the education, all machine operators considered the purpose of the education to be fulfilled. Bravikens t hermomechanical pulp, TMP, system should be developed to reduce the amount of sticky material reaching the paper machine from TMP. More analysis of the whitewater system is needed to determine which method of development that could be implemented to reduce costs and increase functionality of the paper machine. In order to develop the methods of handling deposits, Braviken should continue their work with competence development among the employees. Enhanced competence increases awareness of the problem among machine operators and it facilitates communication between employees who are working to reduce deposit formation. Improved communication also facilitates learning and contributes to the overall competence development at Braviken paper mill.Avsättningar kan bildas i pappersmaskinen på grund av klibbigt material från veden och returpappret. Dessa avsättningar fastnar på processutrustning och medför att slutproduktens kvalité försämras samt att pappersmaskinens verkningsgrad reduceras. Syftet med detta examensarbete är att öka förståelsen om avsättningar bland maskinoperatörer samt ge förslag på metoder som kan användas för att reducera mängden avsättningar på Bravikens pappersmaskiner. För att uppfylla syftet med examensarbetet har en förstudie, en litteraturstudie och intervjuer med maskinoperatörer och personal från Bravikens produktionssektioner, genomförts. Dessa metoder låg till grund för planering och skapande av en utbildning om avsättningar för maskinoperatörer. En utbildning med maskinoperatörer genomfördes för att uppfylla syftet med examensarbetet. Utbildningen innehöll en interaktiv föreläsning för att introducera ämnet avsättningar och ett diskussionsavsnitt. Detta upplägg valdes för att ge maskinoperatörerna möjlighet att diskutera deras arbetssituation på pappersmaskinen relaterat till deras nya kunskaper om avsättningar. Utbildningen genomfördes i hopp om att hitta nya sätt att hantera avsättningsbildningen. Utvärderingen av utbildningen visade att alla deltagande maskinoperatörer ansåg att syftet med utbildningen uppnåddes. För att utveckla Bravikens hanterande av avsättningar bör Bravikens anläggning för att tillverka termomekanisk pappersmassa, TMP, utvecklas för att minska mängden klibbigt material som tar sig vidare till pappersmaskinen, PM. Mer analyser på bakvatten bör också utföras för att avgöra vilken utvecklingsmetod som är möjlig att införa med avseende på kostnad och funktion. Arbetet med att utveckla avsättningshanteringen bör också fortsätta genom kompetensutveckling för de anställda på Braviken. Detta ökar medvetenheten om problematiken bland maskinoperatörerna och förbättrar kommunikationen mellan de olika personalgrupper som arbetar för att minska avsättningsbildningen. Den förbättrade kommunikationen i sin tur underlättar även lärande och bidrar till kompetensutveckling på Bravikens pappersbruk.
30
Pettersson, Emelie. "A study in how rewetting can be reduced in the paper machine with focus on the forming section." Thesis, Högskolan i Borås, Akademin för textil, teknik och ekonomi, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:hb:diva-10827.
Full textAbstract:
This master thesis provides an overview of the paper machine with focus on the forming section. The forming section is the first part in the paper machine where the paper pulp is injected through a head box. The paper pulp contains about 99.5% of water and 0.5% fiber. The water as content is reduced by vacuum and gravity. The problem to be studied in this project is related to external rewetting. This is water going back to the paper web from the forming fabric after the dewatering zone. The dewatering is based on vacuum slots under the forming fabric. The vacuum slots absorb water from the soaked paper pulp through the forming fabric. External rewetting causes problem, hence the paper will have a higher dry content when leaving the forming section. The paper should have as low dry content as possible in the end of the forming section. Three different forming fabrics from Albany International were chosen for the project. The structures of the forming fabrics were two different double layers and one plain weave. The performance of the fabrics was studied by 4 different methods. The methods used were 2 different wicking tests, a vacuum dewatering trial and one foulard test. Also micro tomography was done to understand the structure of each design. The main test was a foulard test where the aim was to see in what way the rewetting got affected by different pores sizes. The results showed higher water content for the paper that was on top of the forming fabric with the larger pores.
31
Wik, Greger. "Headbox Slice Opening Arrangement : An Alternative Solution for Tissue Machines." Thesis, Karlstads universitet, Fakulteten för teknik- och naturvetenskap, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kau:diva-7408.
Full textAbstract:
The head box in a tissue machine distributes the fiber suspension to a flat jet along the width of the machine. By adjusting the so-called lip opening, the flow is regulated and the jet is accelerated to match the machine speed. In this work, ideas for alternative solutions for lip opening mechanism is generated and evaluated with a focus on making a cost saving. One of the concepts has been selected for a deeper analysis with respect to the design, strength and cost. The selected concept is based on reducing the number of jacks required by using one jack operating a shaft parallel to the apron beam. Levers convey the movement to the apron beam. The analysis show that the shaft is exposed to high torque which results in large elastic twisting of the shaft, which means that the force that supports the apron beam will not be equal over the entire width. If the difference in force is too big, the apron beam will twist which results in an uneven lip opening. The shaft stiffness is therefore crucial. For the head box with a width of 2946 mm, the number of jacks is reduced from three to one. Wider head boxes may need more than one jack since the shaft cannot be made to long without getting too much twisted. A lip opening mechanism of the current design with six 20 ton jacks can be compared to the new concept in which only two jacks is needed and the cost is reduced by 18%. There is further potential for savings if the jack, separate gear and electric motor are replaced with an actuator that has the motor mounted directly.Inloppslådan i en tissuemaskin har till uppgift att fördela fibersuspensionen till en flat stråle längs maskinens bredd. Genom att justera den så kallade läppöppningen regleras flödet och strålen accelereras för att passa maskinhastigheten. I detta arbete har idéer till alternativa lösningar för läppöppningsmekanismen genererats och utvärderats med fokus på att göra en kostnadsbesparing. Ett av koncepten har valts ut för en djupare analys med avseende på konstruktion, hållfasthet och kostnad. Det valda konceptet bygger på att reducera antalet domkrafter som behövs genom att en domkraft driver en axel parallell med utloppsbordet. Hävarmar överför rörelsen till utloppsbordet. Analysen visar att axeln utsätts för ett stort moment vilket ger en stor elastisk vridning av axeln, vilket gör att kraften som håller emot utloppsbordet inte blir lika stor över hela bredden. Om skillnaden i kraft är för stor ger det en förvridning av utloppsbordet som resulterar i en ojämn läppöppning. Axelns styvhet är alltså avgörande. För den undersökta lådan med bredden 2946 mm har antalet domkrafter reducerats från tre stycken till en. För bredare inloppslådor behövs fler domkrafter då axeln inte kan göras för lång utan att få för mycket vridning. Ett läppöppningsarrangemang som idag har sex stycken domkrafter kan jämföras med det nya konceptet där det krävs endast två domkrafter och kostnaden minskas med ca. 18%. Ytterligare potential till besparing finns om man byter ut domkraft, separat växel och elmotor till ett ställdon som har motorn direktmonterad.
32
Melin, Timothy R. "Investigating Wood Welding Parameters Using a Prototype Welding Machine." DigitalCommons@CalPoly, 2010. https://digitalcommons.calpoly.edu/theses/420.
Full textAbstract:
Understanding how different processing variables influence wood welded bonds is vital if the technique will ever be used to create engineered lumber without using adhesives. A variation of vibration welding, wood welding uses pressure and friction to bond materials together. During welding, heat causes a softening in the wood, a naturally occurring composite material. This softening leads to fiber entanglement and a bond forms upon cooling.
The goal of this research was to investigate several processing aspects of the wood welding procedure. A prototype wood welding machine, designed and fabricated from the ground up, was used to investigate the effects of various welding parameters using birch wood. Wood welds were evaluated on the basis of bond coverage and ultimate shear strength.
Four experiments were performed: welding frequency and duration interaction, grain orientation effects, alternative welding completion metrics, and strength development over time. During the wood welding process, three distinct phenomena were repeatedly observed: smoke creation, welding residue formation, and an audible pitch change. The presence of each was recorded for every wood welded specimen and used later in additional data analysis. Investigating each of the welding phenomena was done in an attempt to better characterize when fusion was achieved at the weld interface.
ImageTool, an image analysis software package, was used to investigate and quantify the often irregular bonds exposed after shear fracture. The results of the various welding variables were analyzed on the basis of shear strength and bond uniformity.
From the birch samples, it was shown that better bonds result from lower welding frequencies and longer welding durations. The grain orientation analysis demonstrated that welding orientation marginally affects the average shear strength of the wood weld. The data from the alternative welding metrics suggests that welding time is not a quality indicator of welding completion (bond coverage). The strength development trials confirmed previous research; wood welds obtain most of their strength in a relatively short period of time.
Douglas fir and poplar both proved to be weldable for the first time, but they were sufficiently weaker than birch. When welding was attempted with Douglas fir under similar pressures used for birch, Douglas fir samples would commonly “washboard.” With reduced welding pressure, Douglas fir formed wood welds more easily.
33
Alm, Therese. "Characterization of retention chemicals and their effect on the paper forming process on machine PM4, Billerud Korsnäs Gävle Mill." Thesis, Örebro universitet, Institutionen för naturvetenskap och teknik, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:oru:diva-93424.
Full textAbstract:
In the papermaking industries spots in the finished product is a recurring problem. Billerud Korsnäs have in earlier studies identified poorly optimized retention systems as one of the reasons for these spots. Poorly optimized retention systems will allow for detrimental substances to flow freely in the system, which may cause agglomeration into larger particles that could end up as darker spots in the finished product. The aim of this thesis is to investigate a number of retention systems, consisting of a retention polymer and retention microparticles, and characterize the polymers.The retention aid systems task is to flocculate fibres, fines and fillers along with the colloidal material to improve process parameters. To investigate the retention systems three different retention polymers with different charge densities have been investigated alongside one microparticle. The parameters investigated in this thesis were the retention systems effect on drainage time, turbidity, charge demand and zeta potential. Pulp and white water from PM4 was used to imitate mill conditions.The results showed that the drainage time and turbidity was most effected by the retention aid systems. The polymer with the highest charge yielded the best results. Only minor effects could be detected on charge demand and Zeta potential.
34
Drummond, Daniela Medeiros Devienne. "Otimização do setor de prensagem por meio de planejamento de produção em uma industria de papel." [s.n.], 2008. http://repositorio.unicamp.br/jspui/handle/REPOSIP/266229.
Full textAbstract:
Orientadores: Reginaldo Guirardello, Maria Teresa Moreira Rodrigues, Ignacio E. GrossmannTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Quimica
Made available in DSpace on 2018-08-11T14:00:07Z (GMT). No. of bitstreams: 1 Drummond_DanielaMedeirosDevienne_D.pdf: 2651709 bytes, checksum: 8eda6bf1eb834515f79e1109e462fc7b (MD5) Previous issue date: 2008
Resumo: A seção de prensagem é uma importante parte da máquina de papel, afetando as propriedades do produto, bem como interferindo no custo final de fabricação. O setor de prensagem é responsável pela retirada da água da folha, através de ação mecânica no NIP (zona de contato entre por dois rolos). Baixa eficiência deste setor acarreta inconveniente como à elevação do número de quebras da folha, pela diminuição da resistência à tração; aumento no consumo de vapor na seção secadora da máquina, e em muitos casos, a redução da produtividade devido à redução da velocidade da máquina. A eficiência da prensagem é muito importante: primeiro, uma grande quantidade de água deve ser removida da folha nas prensas para se obter economia na secagem; em segundo lugar, a maior eficiência na remoção de água produz uma folha mais seca e, portanto, mais resistente e menos sujeita a quebras. Na entrada das prensas, o conteúdo seco da folha varia entre 18 a 26 % e na saída varia entre 44 até 50 %. Nos últimos anos, observou-se uma evolução bastante rápida dos conceitos de prensas, buscando uma adequação das exigências tais como economia no processo operacional, aumentando a remoção de água neste setor e ao mesmo tempo mantendo ou melhorando as características da folha de papel; e ainda novas demandas de eficiências exigidas nas máquinas. A redução de 1% de umidade da folha provoca uma redução do consumo de vapor na ordem de 4 a 5%. Este trabalho apresenta o desenvolvimento de um modelo matemático para otimização do setor de prensagem de uma máquina de papel através do seqüenciamento de produção de bobinas. O modelo foi desenvolvido em MILNP, o software utilizado para a modelagem foi o GAMS e o solver utilizado foi CPLEX10. Obtivemos uma redução média 46% nas trocas de feltros, juntamente com um aumento de 5% na remoção de água e 12% na produção de bobinas
Abstract: The process of paper manufacture is essentially the removal mechanics of a fiber suspension, starting in the formation where relatively low level of force mechanics is used to remove the free water between staple fibers. The biggest force mechanics used for continuous removal of this water is in the section of presses, where the located one between them in such a way involves the compression of the leaf for water withdrawal of the interior of staple fibers how much. The more compressed the leaf, greater the amount of water is removed. The pressing is made with the leaf in contact with one or two felts in NIP (zone of contact between two rolls). The press sector is an important part of the machine, affecting the properties of the paper, as the smoothness and the density, as well as intervening with the final cost of manufacture. Low efficiency of this sector causes inconvenience as to the rise of the number of in additions the leaf, for the reduction of the tensile strength; increase in the vapor consumption in the drying section, and in many cases, the reduction of the productivity due to reduction of the speed of the machine. The reduction of 1% of humidity of the web the reduction of the steam consumption in the order of 4 5%. This work has as objective the development of a mathematical model for optimization of the press section of a machine of paper through the sequence of production of reels. The model was developed in MILNP, the software used for the modeling was the used GAMS and solver was CPLEX10. We got an average reduction 46% in the replacement of felts, together with an increase of 5% in the removal of water and 12% in the production of reels
Doutorado
Desenvolvimento de Processos Químicos
Doutor em Engenharia Química
35
Lundskog, Måns. "Analysis of 3D design tools for tubing and piping design : Evaluating E3D and CATIA for on-machine tubing and piping design of paper machines using the analytic hierarchy process." Thesis, Karlstads universitet, Institutionen för ingenjörsvetenskap och fysik (from 2013), 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:kau:diva-72960.
Full textAbstract:
This thesis covers a degree project for a Bachelor of Science in mechanical engineering degree and is written on behalf of Valmet AB. The purpose of the project is to evaluate and analyse the differences between CATIA and E3D and conclude which of the software is most suitable for on-machine tubing and piping design at Valmet. The tubing and piping modules in CATIA are currently used but is considered somewhat ineffective. E3D is also used at Valmet but in another branch of engineering design, namely field pipe engineering. The analysis is done using the analytic hierarchy process (AHP) which is a multi-criteria decision making (MCDM) methodology developed to aid in complex decision-making problems. The methodology follows a six-step process which results in a prioritized ranking or relative weight of both alternatives with respect to the established criteria and sub-criteria for selection. A total of four main criteria and 12 sub-criteria for the selection of the most suitable CAD system were identified and analysed with the help of relevant personnel in various departments such as engineering, purchasing and management The results of the project conclude that E3D is the preferred CAD system for on-machine tubing and piping at Valmet with regards to the given criteria and sub-criteria. The criteria that favoured E3D most were the availability of the systems, meaning the possibility that Valmet can outsource projects to consultants, as well as the more effective 3D modelling process. However, the results are not heavily one-sided which suggest that more research should be done before a final decision can be taken. The suggested further research includes looking at the in-direct implications of using a new CAD system such as computer updates and the usage of a new PLM system. Moreover, the actual performance of 3D modelling using the two systems is beyond the scope of this thesis and would have to be further researched in another thesis or a pilot case.
36
Риляков, Ілля Леонідович. "Підвищення ефективності технології виробництва сигаретного паперу." Master's thesis, КПІ ім. Ігоря Сікорського, 2020. https://ela.kpi.ua/handle/123456789/38492.
Full textAbstract:
Актуальність теми. Розширення сировинної бази целюлозно-паперової галузі України за рахунок використання целюлози з відходів сільського господарства. Виробництво сигаретного паперу та забезпечення стабільності його якості шляхом використання новітніх досягнень в паперовому виробництві та сучасних технологій одержання целюлози.
Мета і задачі дослідження. Метою дисертаційної роботи є вивчення особливостей сигаретного паперу та вдосконалення технології його виробництва для підвищення якості продукції.
Для досягнення вказаної мети було поставлено наступні задачі:
- ознайомлення з властивостями сигаретного паперу;
- одержати солом'яну целюлозу окисно-органосольвентним способом делігніфікації та дослідити її паперотворні властивості;
- вдосконалити технологічний процес виробництва сигаретного паперу;
- вибрати і розрахувати основне технологічне обладнання.
- провести аналіз потенціалу даної роботи до використання у стартапі.
Об’єкт дослідження: процеси одержання соломяної целюлози та виготовлення сигаретного паперу.
Предмет дослідження: технологічні параметри процесу делігніфікації січки пшеничної соломи, параметри процесів формування, пресування, проклеювання і сушіння паперового полотна.
Методи дослідження: для визначення впливу технологічних параметрів одержання целюлози використовували хімічні, фізико-хімічні та фізико-механічні методи аналізу.
Обгрунтування іноваційних рішень в технологічному потоці базувалося на теоретичних методах аналізу.
Практичне значення одержаних результатів: запропонований технологічний потік з виробництва виробництва сигаретного паперу з використанням соломяної целюлози дозволить покращити якість готової продукції та зменшити її собівартість.
Апробація результатів дисертації:
Основні положення дисертаційної роботи доповідалися та обговорювалися на міжнародній закордонній конференції IV international scien-tific and practical conference The world of scitnce and innovation, London, United Kingdom, 11-13 november, 2020 р.Theme actuality. Expansion of the raw material base of the pulp and paper industry of Ukraine due to the use of pulp from agricultural waste. Production of cigarette paper and ensuring the stability of its quality through the use of the latest advances in paper production and modern technologies for pulp production. The purpose and objectives of the study. The purpose of the dissertation is to study the features of cigarette paper and improve the technology of its production to improve product quality. To achieve the goal, you need to solve the following tasks: - acquaintance with the properties of cigarette paper; - to obtain straw cellulose by oxidative-organosolvent method of delignification and to investigate its paper-forming properties; - to improve the technological process of cigarette paper production; - select and calculate the main technological equipment. - to analyze the potential of this work for use in startups. Object of study: the process of making document paper. Subject of study: processes of production of straw cellulose and production of cigarette paper. Methods of study: technological parameters of the process of delignification of wheat straw chips, parameters of the processes of forming, pressing, gluing and drying of paper web. The practical value of the obtained results: the proposed technological stream for the production of cigarette paper with the use of straw pulp will improve the quality of finished products and reduce its cost. Approval of the thesis results: The main provisions of the dissertation were reported and discussed at the international international conference IV international scien-tific and practical conference. The world of science and innovation, London, United Kingdom, 11-13 November, 2020.
37
Printsypar, Galina [Verfasser], and Oleg [Akademischer Betreuer] Iliev. "Mathematical Modeling and Simulation of Two-Phase Flow in Porous Media with Application to the Pressing Section of a Paper Machine / Galina Printsypar. Betreuer: Oleg Iliev." Kaiserslautern : Universitätsbibliothek Kaiserslautern, 2012. http://d-nb.info/1022804308/34.
Full text
38
Škrobánek, Martin. "Diagnostický systém papírenského stroje." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2020. http://www.nusl.cz/ntk/nusl-417858.
Full textAbstract:
This master thesis deals with the technical diagnostics, focusing mainly on vibration diagnostics. This problematice is described in the first part of this work on a theoretical level. The next part describes the paper machine, diagnostic system and the measuring points are classified into databases. The practical part of this work consists of a proposal for the methodology of vibration diagnostics for a paper machine, the procedure for measuring and evaluating the measured values. Part of the work is also a practical example of the measurement of the central cylinder, on which the procedure is tested, and the compilation of new limit values.
39
Nystad, Marcus, and Lukas Lindblom. "Artificial Intelligence in the Pulp and Paper Industry : Current State and Future Trends." Thesis, KTH, Skolan för industriell teknik och management (ITM), 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-279574.
Full textAbstract:
The advancements in Artificial Intelligence (AI) have received large attention in recent years and increased awareness has led to massive societal benefits and new opportunities for industries able to capitalize on these emerging technologies. The pulp and paper industry is going through one of the most considerable transformations into Industry 4.0. Integrating AI technology in the manufacturing process of the pulp and paper industry has shown great potential, but there are uncertainties which direction companies are heading. This study is an investigation of the pulp and paper industry in collaboration with IBM that aims to fill a gap between academia and the progress companies are making. More specifically, this thesis is a multiple case study of the current state and barriers of AI technology in the Swedish pulp and paper industry, the future trends and expectations of AI and the way organizations are managing AI initiatives Semi-structured interviews were conducted with 11 participants from three perspectives and the data was thematically coded. Our analysis shows that the use of AI varies, and companies are primarily experimenting with a still immature technology. Several trends and areas with future potential were identified and it was shown that digital innovation management is highly regarded. We conclude that there are several barriers hindering further use of AI. However, continued progress with AI will provide large benefit long term in areas such as predictive maintenance and process optimization. Several measures taken to support initiatives with AI were identified and discussed. We encourage managers to take appropriate actions in the continued work toward AI integration and encourage further research in the area of potential reworks in R&D.Framgångarna inom Artificiell Intelligens (AI) har fått stor uppmärksamhet de senaste åren och ökad medvetenhet har lett till stora fördelar för samhället liksom nya möjligheter för industrier som tar vara på dessa nya teknologier. Pappers- och massa industrin genomgår en av de mest omfattande transformationerna mot Industri 4.0. Integreringen av AI-teknologi i industrins tillverkningsprocesser has visat stor potential, men också osäkerhet kring vilken riktning företag är på väg mot. Denna studie är en undersökning av den svenska pappers- och massaindustrin, i samarbete med IBM, som syftar till att minska gapet mellan akademin och framstegen företag inom industrin tar. Mer specifikt är denna uppsats en kombinerad fallstudie av det nuvarande läget, barriärerna till AI-teknik i den svenska pappers- och massa industrin, de framtida trenderna och förväntningarna på AI och metoderna företag använder för att stötta AI-initiativ. Semi-strukturerade intervjuer genomfördes med 11 deltagare från tre olika perspektiv och datan var tematiskt kodad. Vår analys visar att användning av AI varierar och företag experimenterar huvudsakligen med omogen teknik. Flera trender och områden med potential för framtiden identifierades och det visades att digital innovationshantering är högt ansedd. Vi sammanfattar med att det finns flera barriärer som hindrar fortsatt användning av AI. Fortsatt arbete med AI-tekniken kommer leda till stora fördelar på lång sikt inom områden som prediktivt underhåll och fortsatt processoptimering. Flera åtgärder för att stötta AI-initiativ var identifierade och diskuterades. Vi uppmuntrar industrin att genomföra lämpliga åtgärder i det fortsatta arbetet mot AI-integration och uppmuntrar fortsatt forskning inom potentiella omstruktureringar inom FoU.
40
Sjunnesson, Helene. "Papper och lump : studier av kontinuitet och förändring i nordisk pappersindustri från 1600-tal till 1900-tal." Licentiate thesis, KTH, Philosophy and History of Technology, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-3977.
Full textAbstract:
. This thesis consists of an introduction and four previously published articles. The joint empirical focus is papermaking based on textile rags as fibre raw material. Furthermore the physical environment is central in the studies. The relationship between continuity and change is a prevailing theme. The thesis also pays attention to the use of different sorts of rags and to the connection between this kind of papermaking and the textile industry.
The overall purpose is to throw new light upon the paper industry based on rags – a part of early industry seldom mentioned in historical surveys of the industrialization process in Sweden. The aim is also to question the prevalent Swedish historical writing commissioned by the branch, characterized by set divisions between different phases of technical and industrial development, from simple craft to modern industry. One of these borderlines has been drawn between papermaking by hand and papermaking by machine, with the 1830s as the selected transition period. By studying and analysing changes in the traditional and seemingly static papermaking as well as the opposite: the traditional that has lingered in the new, this thesis shows that the course of events was much more complicated than that. An outcome of the studies is that the industrialization of the rag based paper industry has been a complex, uneven and prolonged process.
The first main part of the thesis consists of two Swedish regional studies centred on the province of Östergötland in a long-time perspective. The focus is mainly on the long continuity of papermaking by hand, which was carried out between 1628 and 1968. The study shows that a variety of types and sizes of mills regarding ownership, forms of production, location, paper qualities and techniques can be identified. Continuity was the dominating feature but within this framework technological and industrial change also took place.
The second main part of the thesis has a Nordic perspective and deals with a shorter period, mainly 1830-1870. One study examines the introduction of the paper-machine and the establishment of the first machine-made paper mills in Denmark, Sweden, Norway and Finland with special attention given to the Swedish mill Holmen in Norrköping and the Finnish Tammerfors mill, both situated in textile mill towns. A second Nordic study surveys hand-made paper mills founded during and after the time when the paper-machine technology had been established. As the studies show, two parallel development tracks were prevalent in the paper industry in the Nordic countries during the period 1830-1870 – papermaking by machine and papermaking by hand.
The first paper machines were imported from Britain to some of the oldest and largest paper mills. The introduction of the new technology led to changes in for instance the paper mill buildings and the organization of work regarding the papermaking process. In the preparatory and finishing work manual methods remained, and as before it employed mostly women.
At the same time, papermaking by hand continued to change and new hand-made paper mills were founded until as late as the 1890s. The study discusses possible explanations, among them growing markets for special qualities and combinations with other branches of industry.
All the studies show a connection between hand-made paper mills and wool mills on one hand, and machine-made paper mills and cotton and linen mills on the other hand. The paper industry based on rags could in fact be characterized as a kind of textile industry
41
Zborník, Radek. "Návrh úpravy nosné konstrukce lisové části papírenského stroje." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2018. http://www.nusl.cz/ntk/nusl-377652.
Full textAbstract:
The thesis deals with a description and a strength analysis of selected parts of a modified supporting structure of a press part of a paper machine. The construction is designed to simplify a replacement of felt belts during a service shutdown of the machine. The first part of the thesis is devoted to a brief description of the paper machine with a more detailed focus on the press part. The next part of the thesis includes a project of adjustment to the original design of the supporting structure. The last part deals with a strength control of construction nodes of the adjusted project. A strength calculation is further divided into a calculation using the finite element method and an analytical calculation. Results of both previous calculation methods are compared at the end of the thesis.
42
Narmack, Kirilll. "Dynamic Speed Adaptation for Curves using Machine Learning." Thesis, KTH, Skolan för elektroteknik och datavetenskap (EECS), 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-233545.
Full textAbstract:
The vehicles of tomorrow will be more sophisticated, intelligent and safe than the vehicles of today. The future is leaning towards fully autonomous vehicles. This degree project provides a data driven solution for a speed adaptation system that can be used to compute a vehicle speed for curves, suitable for the underlying driving style of the driver, road properties and weather conditions. A speed adaptation system for curves aims to compute a vehicle speed suitable for curves that can be used in Advanced Driver Assistance Systems (ADAS) or in Autonomous Driving (AD) applications. This degree project was carried out at Volvo Car Corporation. Literature in the field of speed adaptation systems and factors affecting the vehicle speed in curves was reviewed. Naturalistic driving data was both collected by driving and extracted from Volvo's data base and further processed. A novel speed adaptation system for curves was invented, implemented and evaluated. This speed adaptation system is able to compute a vehicle speed suitable for the underlying driving style of the driver, road properties and weather conditions. Two different artificial neural networks and two mathematical models were used to compute the desired vehicle speed in curves. These methods were compared and evaluated.Morgondagens fordon kommer att vara mer sofistikerade, intelligenta och säkra än dagens fordon. Framtiden lutar mot fullständigt autonoma fordon. Detta examensarbete tillhandahåller en datadriven lösning för ett hastighetsanpassningssystem som kan beräkna ett fordons hastighet i kurvor som är lämpligt för förarens körstil, vägens egenskaper och rådande väder. Ett hastighetsanpassningssystem för kurvor har som mål att beräkna en fordonshastighet för kurvor som kan användas i Advanced Driver Assistance Systems (ADAS) eller Autonomous Driving (AD) applikationer. Detta examensarbete utfördes på Volvo Car Corporation. Litteratur kring hastighetsanpassningssystem samt faktorer som påverkar ett fordons hastighet i kurvor studerades. Naturalistisk bilkörningsdata samlades genom att köra bil samt extraherades från Volvos databas och bearbetades. Ett nytt hastighetsanpassningssystem uppfanns, implementerades samt utvärderades. Hastighetsanpassningssystemet visade sig vara kapabelt till att beräkna en lämplig fordonshastighet för förarens körstil under rådande väderförhållanden och vägens egenskaper. Två olika artificiella neuronnätverk samt två matematiska modeller användes för att beräkna fordonets hastighet. Dessa metoder jämfördes och utvärderades.
43
Sancandi, Marc. "Modélisation et simulation du pressage humide sur machine à papier." Grenoble INPG, 1990. http://www.theses.fr/1990INPG0053.
Full textAbstract:
La base de cette etude est le modele de pressage humide developpe par roux (ecoulements bidimensionnels en non sature) que nous etendons a la prise en compte des feutres. La premiere partie de ce travail consiste en un survol rapide des differents modeles qui, de celui de whalstrom a celui de roux, ont jalonne l'histoire du pressage. Dans la seconde partie nous proposons une description des differents phenomenes intervenant dans la pince a l'aide d'un formalisme mixte de type arbitraire-lagrangien-eulerien (a. L. E. ). Nous montrons comment ce formalisme permet une modelisation correcte du probleme et nous indiquons que les equations obtenues sont tres proches de celles donnees par roux. La partie suivante traite de la resolution du systeme d'equations couplees non lineaires qui composent le modele. Grace au formalisme a. L. E. Nous construisons un schema iteratif de resolution qui separe les contributions de la phase solide et des deux phases fluides. Le solide est traite par elements finis et les fluides par volumes finis avec decentrage amont des termes convectifs dominants. Dans la quatrieme partie nous presentons quelques resultats classiques qui permettent de verifier le bon comportement qualitatif du modele. Les resultats suivants sont plus originaux et simulent (a notre connaissance pour la premiere fois) l'influence du feutre dans le processus d'evacuation de l'eau. Un chapitre est d'ailleurs consacre a une etude critique du modele. Nous concluons ce travail en proposant quelques ameliorations sur le plan numerique et en montrant comment des lois de comportement plus sophistiquees peuvent etre prises en compte
44
Rioux, Robert A. "Mechanical Testing of Coated Paper Systems." Fogler Library, University of Maine, 2008. http://www.library.umaine.edu/theses/pdf/RiouxRA2008.pdf.
Full text
45
Gattuso, Claude F. "Laser perforation for computer paper /." Online version of thesis, 1989. http://hdl.handle.net/1850/11526.
Full text
46
Ahola, T. (Timo). "Intelligent estimation of web break sensitivity in paper machines." Doctoral thesis, University of Oulu, 2006. http://urn.fi/urn:isbn:9514279573.
Full textAbstract:
Abstract
The ambition to increase the production of paper has made paper machine runnability widely studied in recent decades. Paper machine runnability is often measured by the number of web breaks in comparison with paper machine speed. When runnability is good, a machine can be run at the desired speed with the least possible number of breaks. Web break sensitivity means the number of breaks in a day, which can also be understood as a measurement of paper machine runnability.
This study presents an application for the evaluation of web break sensitivity in a paper machine. A web break sensitivity indicator was built using the basic principles of case-based reasoning with a linguistic equations approach and basic fuzzy logic. The indicator combines on-line measurement data with expert knowledge and provides a continuous indication of break sensitivity. Web break sensitivity defines the current operating situation at the paper mill and provides new information to operators. Web break sensitivity is presented as a continuous signal with information about actual web breaks depicted as an eight-hour trend. The trend shows how the situation has developed and the current value gives a prediction for the next 24 hours if the situation stays as it is now. Together with information about the most important variables, this prediction gives operators enough time to react to the changing operating situation.
From the methodological point of view, a new tool for building case-based reasoning applications for other purposes was also tested and found to be suitable for diagnostic applications.
47
McClendon, Jerome Gilbert Juan E. "A new approach to voting an accessible voter verifiable paper ballot /." Auburn, Ala, 2009. http://hdl.handle.net/10415/1813.
Full text
48
Guerrier, Christian. "Développement d'un appareil de laboratoire permettant de simuler le comportement d'une suspension fibreuse sur la toile d'une machine à papier." Grenoble INPG, 1988. http://www.theses.fr/1988INPG0095.
Full textAbstract:
La formette reproduit plusieurs phases du processus : conditionnement de la suspension fibreuse, egouttage pulse et premiere consolidation. Elle est equipee d'une instrumentation reliee a un microordinateur qui assure la conduite automatique et l'acquisition des mesures. On presente une methode de caracterisation de la formation et on etudie l'influence de l'amplitude et de la frequence des pulsations de pression sur les caracteristiques du matelas fibreux en relation avec les resultats connus pour un systeme industiel. On analyse les mecanismes d'extraction de l'eau capillaire dans la phase ou le matelas fibreux n'est plus sature. Enfin, on etudie la proprietes structurales, de contexture et physiques des papiers et on etablit des correlations avec les proprietes des papiers industriels
49
Sonal, Manish. "Machine Learning for PAPR Distortion Reduction in OFDM Systems." Thesis, KTH, Signalbehandling, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-197682.
Full textAbstract:
The purpose of the project is to investigate the possibility of using modern machine learning to model nonlinear analog devices like the Power Amplifier (PA), and study the feasibility of using such models in wireless systems design. Orthogonal frequency division multiplexing (OFDM) is one of the most prominent modulation technique used in several standards like 802.11a,802.11n, 802.11ac and more. Telecommunication systems like LTE, LTE/Aand WiMAX are also based on OFDM. Nevertheless, OFDM system shows high peak to average power (PAPR) in time domain because it comprises of many subcarriers added via inverse fast Fourier transform(IFFT). HighPAPR results in an increased symbol error rate, while degrading the efficiency of the PA. Digital predistortion (DPD) still suffers from high symbol error rate (SER) and reduced PA efficiency, when there is an increase in peak back off(PBO). A receiver based nonlinearity distortion reduction approach can be justified by the fact that base stations have high computation power. A iterative-decision-feedback mitigation technique can be implemented as a receiver side compensation assuming memoryless PA nonlinearities. For successful distortion reduction the iterative-decision based technique required the knowledge of the transmitter PA. The author proposes to identify the nonlinear PA model using machine learning techniques like nonlinear regression and deep learning. The results show promising improvement in SER reduction with small PA model learning time.Syftet med detta projekt är att undersöka möjligheterna att använda modernmaskininlärning för att beskriva ickelinjära analoga enheter såsom effektförstärkareoch att studera hur användbart det är att använda sådana modeller föratt designa trådlösa kommunikationssystem. OFDM (ortogonal frekvensmultiplex)är en av de vanligast förekommande modulationsteknikerna, som användsi standarder såsom 802.11a, 802.11n, 802.11ac and andra. Telekommunikationssystemsom LTE, LTE/A och WiMAX baseras också på OFDM. Dock resulterarOFDM i hög toppeffekt i förhållande till medeleffekten (hög PAPR) i tidsdomänen,eftersom signalen består av många delkanaler som summeras mha inversdiskret fouriertransform (IFFT). En hög PAPR resulterar i ökad symbolfelshaltoch försämrar effektiviteten hos effektförstärkaren. Digital predistortion (DPD)kan förbättra situationen men ger fortfarande hög symbolfelshalt och försämradförstärkareffektivitet, när man drar ned sändeffekten för undvika kvarvarandeickelineariteter. Att minska förvrängningen från ickelineariteterna vid mottagarenkan motiveras i system där basstationerna har hög beräkningsförmåga. Enmetod för att reducera förvrängningarna kan implementeras på mottagarsidan,baserad på iterativ beslutsåterkoppling, under antagandet om att sändarens effektförstärkarehar en minneslös ickelinearitet. För att störningsreduceringenska fungera väl, krävs god kunskap om sändarens effektförstärkare. Författarenföreslår att identifiera en ickelinjär modell för förstärkaren mha maskininlärningstekniker,såsom ickelinjär regression och djup inlärning. Resultaten visarlovande förbättringar av symbolfelshalten med en låg inlärningstid för förstärkarmodellen.
50
Кушніров, Павло Васильович, Павел Васильевич Кушниров, Pavlo Vasylovych Kushnirov, and А. А. Косенко. "Усовершенствование оснастки для обработки столов бумагорезательных машин." Thesis, Изд-во СумГУ, 2010. http://essuir.sumdu.edu.ua/handle/123456789/5451.
Full text