Dissertations / Theses on the topic 'Pump'

With increasing energy costs and competitive pressures, interest has increased in surveying installed pumps for potential energy savings. Field pump efficiency tests are required to assess pumping performance and help to identify improvement opportunities. This work concerns the on-site measurements of pulp-suspension pumping efficiency. This involves the measurement of pump head, flow rate and power consumption. Provided that consistent flow measurements are available, it is possible to reliably and non-invasively measure actual pump system efficiencies in pulp suspension flow, with a minimum process disturbance. As part of a most appropriate measurement-procedure study, four portable nonintrusive flow meters were evaluated on site for pulp suspension flow. The Fast Fourier Transform Doppler was found to be the most suitable for a pulp mill pump survey. Efficiency measurements were performed on six pump systems with motors between 100 and 700 HP. It is shown that as-installed pump efficiency can be used to help predict the degradation of the pump and also its effect on the pumping system’s operation. A system approach analysis was performed in each case, which can be effective in assessing system performance and finding potential enhancements. The use of variable speed drives allows the operating point to move along the system curve, requiring less energy to drive the pump. VSD of larger motors are expensive and their profitability compared to other modification alternatives should always be carefully checked by calculations based on accurate on site measurements and life cycle costs. Finally, in this survey of six pump systems, significant potential savings of around 30% of present power consumption were found.

The interest for power and energy measurement has greatly raised with todays increasing electricity prices and enviromental awareness. In the search for energy efficient solutions, the measurements are more complex due to increasing of non linear components. Harmonics and non sinusoidal voltages put high demands on sampling and filtering. Meanwhile, the price must be controlled so the customer still will find it interesting to invest in smaller plants. ITT W&WW asks for a robust, heat resistant power meter with compact dimensions to allow mounting inside the casing of a pump. It should be able to measure the power, both from a regular power supply and fed from a VFD. The accuracy needs not to be on reference level, but the price/performance-ratio is an important parameter. Synchronous sample is tested, but is not considered suitable. Several test kits designed for 50 Hz AC, turn out to also measure VFD feed loads with good accuracy.

Mycronic is a company that manufactures a solder paste printer used to manufacturecircuit boards. Inside the printer solder paste is fed with the help of a screw pump.The solder paste, consisting of relatively soft metals has a tendency to stick to thescrew surface and form particles. These are then detached and passed on in thesystem and can clog the nozzle of the printer. This project investigated the possibilityof creating a model test where different parameters can be varied to evaluate itsinfluence on the amount of solder paste sticking to the surface of the screw. Testingthese parameters directly in the solder paste printer would be time consuming andexpensive.A pin-on-disk set up with some modified parts was used to emulate the solder pastemotion in the screw pump. The results were then analyzed in light optical microscope(LOM) and scanning electron microscope (SEM) equipped with energy dispersivex-ray spectroscopy (EDS).The parameters that were varied were pressure, temperature, rotation speed,substrate, content of the paste and the shape of the profile, which is supposed toemulate the ridge of the screw. It was shown that the profile shape, the substrate andthe pressure was of great importance in the deformation of the solder balls while therotation speed and the paste content had a small or no effect.The goal of the project is to recreate the agglomerates that have led to malfunctionsin the printing and evaluate which parameters that have the greatest significance.

Thesis (B.S.)--California Polytechnic State University, 2009.
Project advisor: Tom Mase. Title from PDF title page; viewed on Jan. 13, 2010. Includes bibliographical references. Also available on microfiche.

Målet med det här projektet är att bygga ett tillförlitligt pumpsystem som inte är beroende av elektricitet eller icke förnyelsebara bränslen. Pumpen ska klara att pumpa 50-100 liter per dygn till en höjd av 10 meter. Konstruktionen ska placeras i indianbyn El Vergel i Amazonas, Colombia. Pumpen ska pumpa orent vatten till vattenreningstunnor de månader som invånarna i byn inte har tillgång till regnvatten.

Olika koncept arbetades fram och utvärderades. Det som valdes var en cykeldriven vattenpump, vilken uppfyllde alla krav.

Pumpens axel är kopplad till bakhjulets fälg med en kilrem. När tramporna snurrar så överförs kraften från det främre kugghjulet till det bakre med cykelkedjan och sen med kilremmen från fälgen till pumpaxeln. Konstruktionen är enkel och den är lätt att laga om den går sönder. Resultaten är en tillförlitlig pump som pumpar med ett jämt flöde.

This study aimed at refining and improving current methodology concerning large-scale heat pump performance. This study was performed on two large-scale ground source heat pumps located in Solna (Stockholm). These were connected to an aquifer thermal energy storage system which provided heating and cooling for two office buildings. The heat pumps had been equipped with preliminary sensors from the BMS (Building management system) and been in operation since 2016. In 2019, additional detailed measurement equipment from ClimaCheck was installed to collect comprehensive data from the heat pumps to allow a more comprehensive performance evaluation. This study was primarily performed by data pre-processing of the BMS-data and the ClimaCheck-data. Once this was done, the ClimaCheck parameters were backtracked and recalculated. Subsequently new models for system evaluation was implemented. The most desired parameter to replace in the ClimaCheck model was the mass flow rate, which they obtain though an energy balance over the compressors. The latter part of the study was to see whether the BMS had sufficient data to provide the same information as ClimaCheck. This was done by implementing a regression of the BMS-data, where the heating and cooling capacities from ClimaCheck were used as targets. The results from the study showed that implementing a mass flow rate based upon compressor efficiency instead of an assumed heat loss was difficult and only reliable for higher loads. When evaluating the ClimaCheck parameters, interesting results were found concerning their calculations for the heating capacity, which might not be calculated the way they express in their formulas. The regression from the BMS-data was proven difficult because of the insufficient and lacking data for some instances. Five different models were produced and compared, some models showed accuracy up to 95% depending on the desired metric. It can be concluded that it is possible to estimate the key performance indicators using the BMS-data. It yields good results for the COP’s and very accurate results for the SPF’s over a year. This makes it possible to evaluate the heat pump performance for years prior to the installation of the ClimaCheck system.
I den här studien analyseras metodiken för att bestämma prestandan hos industriella värmepumpar. Studien utfördes i Solna utanför Stockholm på ett värmepumpsystem som är kopplat till en grundvattenkälla. Systemet tillförde uppvärmning och kylning till tv˚a kontorsbyggnader. Systemet har varit i drift sedan 2016 och i samband med installation s˚a sattes sensorer upp f¨or att kontrollera systemet. Dessa sensorer ¨ar kopplade till bygnadernas BMS, som är utvecklat av Siemens. I början av 2019 anlitades företaget ClimaCheck för att installera ytterligare ett mätsystem, så att värmepumparnas prestanda kunde analyseras. Denna studie utfördes endast på värmepumparna som bara utgjorde en liten del av hela systemet. Till en början fokuserade studien på analys och databehandling av all data, både på datan från Siemens och ClimaCheck. Med hjålp av den uppmätta ClimaCheck-datan verifierades sedan ClimaChecks metod, genom att implementera ClimaChecks beräkningar i python. Detta gjordes primärt för att både kunna verifiera och sedan kunna implementera en möjlig förbättring i massflödet som ClimaCheck använder i sin modell. Sedan gjordes flera regressionsmodeller med BMS variabler, där targetvariablen sattes till antingen ClimaChecks beräknade värmeeffekt eller kyleffekt, beroende på vilken av dem som analyserades. Anledningen till detta var att BMS-datan inte innehåller de mätpunkter som krävs för att teoretiskt bestämma kapaciteterna. När det nya mass flödet introducerades blev resultatet inte önskvärt och den nya modellen var bara tillämpbar då värmepumparna gick på max effekt. När ClimaChecks beräkningar och parametrar återskapades hittades intressanta resultat angående värmekapaciteten. Den gick inte att återskapa med deras enthalpiberäkningar, utan den hittades istället med en annan metod. Regressionen som gjordes gav goda resultat om man bortser från vissa antaganden som gjorts. Regressionen kunde beroende på vilken parameter som efterfrågades ha en noggrannhet på upp till 95%. Studien visar att ClimaCheck har en bra och fungerande modell men den kan förbättras. Den tar även upp hur viktigt det är med data för att ordentligt och effektivt kunna utvärdera system. Slutligen kommer studien åskådliggöra en god metodik för hur data kan hanteras och tillämpas. Systemutvärdering är av yttersta vikt för att reducera energikostnader och många system skulle behöva utvärderas.

The primary goal for this PhD project has been to investigate instability of reversiblepump turbines (RPTs) as a phenomenon and to find remedies to solve it. The instability occurs for turbines with s-shaped characteristics, unfavourable waterways and limited rotating inertia. It is only observed for certain operation points at either high speed or low load. These correspond to either high values of Ned or low values of Qed. The work done in this PhD thesis can be divided into the three following categories. Investigate and understand the behaviour of a pump turbine: A model was designed in order to investigate the pump turbine behaviour related to its characteristics. This model was manufactured and measurements were performed in the laboratory. By using throttling valves or torque as input the full s-shaped characteristics was measured. When neither of these techniques is used, the laboratory system has unstable operation points which result in hysteresis behaviour. Global behaviour of the RPT in a power plant system was investigated through analytical stability analysis and dynamic system simulations. The latter included both rigid and elastic representation of the water column. Turbine internal flow: The flow inside the runner was investigated by computer simulations (CFD). Two-dimensional analysis was used to study the inlet part of the runner. This showed that a vortex forming at the inlet is one of the causes for the unstable characteristics. Three-dimensional analyses were performed and showed multiple complex flow structures in the unstable operation range. Measurements at different pressure levels showed that the characteristics were dependent on the Reynolds number at high Ned values in turbine mode. This means that the similarity of flows is not sufficiently described by constant Qed and Ned values at this part of the characteristics. Design modifications: The root of the stability problem was considered to be the runner’s geometric design at the inlet in turbine mode. Therefore different design parameters were investigated to find relations to the characteristics. Methods used were measurements, CFD modelling and analytical models. The leading edge profile was altered on the physical model and measurements were performed in the laboratory. Results showed that the profiles have significant influence on characteristics and therewith stability at high speed operation points. Other design parameters were investigated by CFD analysis with special focus on the inlet blade angle.

Solar-powered water pumping is an inherently sensible proposition due to the pump being able to supply water at times when it is most in demand. In general small solar-thermal water pumps hold some promise for low technology applications in developing countries. The aim of this study was to model the characteristics of an appropriate technology water pump and build a concept-proving pump. A detailed computer model of the pump and flat plate collector gave the ability to optimise the pump's dimensions and predict the output for any average day in any location. An exergy analysis showed that the major losses in the system were due to wasteful processes within the pump's operating cycle. The pump took the form of a 450mm diameter double diaphragm suction unit with a predicted operating efficiency of approximately 1% when operating at 68°C. The concept-proving pump was set up using compressed air and preliminary runs on pentane gave an efficiency of 0.3%. The pump takes water from 7 metres below to 1.5 metres above the pump at a rate of 3 litres every 10 seconds. A financial analysis highlighted the fact that the solar pump has higher capital but lower running costs than some of its competitors, and as such would suit certain niche applications. Recommendations are to improve the physical lay-out of the pump and improve the design of several components to enable better performance of the pump operating on the same principle.

Video is available on the UofAZCALS YouTube channel.
Arizona private well owners are responsible for their well water quality. This video shows where to collect water samples and describes the sample collection process in detail for the analysis of contaminants to insure unbiased results.

Thesis (MScEng (Electrical and Electronic Engineering))--University of Stellenbosch, 2009.
The aim of this study is to analyse the operation of a wind-electric pumping system (WEPS) as an alternative to conventional mechanical wind pumps for application in stand-alone water-pumping schemes. The steady-state as well as the dynamic operation of such a system is analysed. Through these analyses, practical guidelines are given in the design and sizing of the different system components to ensure efficient and reliable operation. Theoretical analyses are supported by measured results conducted on a small scale wind-electric pump system. The limitations involved in the design and implementation of a large scale wind-electric pump system are presented through a case study. It is firstly concluded that small-scale wind-electric pump systems have the potential of offering superior performance and flexibility to conventional mechanical wind pumps. It is secondly concluded that large-scale wind-electric pump systems are best suited, in terms of economic and practical feasibility, to pumping applications with low pressures and medium to high wind regimes at the turbine installation site.

Today many tasks are executed by robots, but one business is not affected much by this, that is the restaurant business, and in more particular the bartender business. This project takes on the challenge to build an Open Source bartender robot with cheap parts and research how good precision can be achieved. The project does not take account for different viscosities of the liquids or abnormal temperatures. The key component for this project is the peristaltic pump, which is used to transport the liquid. The pump is an Open Source 3D-printable pump distributed through Thingiverse® and can be modified parametrically in the software OpenSCAD. Other components used in this project are an ArduinoTM Uno and a tachometer. These are put together to a demonstrator which is controlled by a feedback control. A graphical user interface is also constructed using an object based model-view-controller architecture which runs on the programing language PHP on a Raspberry Pi. The testing of the demonstrator shows that the robot has an error of 5 percent when pumping small amounts of liquid. The total cost for this project is 1930 SEK, but it can be dropped lower if a cheaper engine is chosen, resulting in a slower machine.
Idag används robotar inom många branscher i världen. En bransch som inte påverkats mycket av robotindustrin är restaurangbranschen och ännu mer specifikt bartenderbranschen. Det här projektet handlar om att utveckla en bartenderrobot med öppen källkod som använder billiga komponenter och sedan undersöka hur bra precision det det går att få. Projektet tar inte hänsyn till olika viskositeter på vätskorna eller ovanliga temperaturer. Den viktigaste komponenten för detta projekt är den peristaltiska pumpen som används för att transportera vätskan. Pumpen kan 3D-printas, den har en öppen källkod och går att ladda ner ifrån Thingiverse®. Den är parametriserad i programmet OpenSCAD så den är lätt att modifiera. Andra komponenter som används i detta projekt är ArduinoTM Uno och en varvräknare som sätts ihop till en prototyp som styrs via ett återkopplat system. Även ett grafiskt gränssnitt är byggt på en objektbaserad model-view-controller arkitektur som körs i programspråket PHP på en Raspberry Pi. Tester av prototypen visar att det maximala felet är 5 procent när små volymer pumpas. Den totala kostnaden för detta projekt blev 1930 SEK men det går att få en lägre kostnad om en annan motor väljs. Detta gör dock att det tar längre tid att hälla upp vätska.

An innovative pump, TurboPiston Pump, has been invented to incorporate the merits of centrifugal, axial, and positive displacement pumps. The TurboPiston pump is designed to deliver large flow rates at very high pressure of up to 1000 psia. To improve the original design, an understanding of flow behavior inside the pump is needed. Therefore, this thesis focuses on simulating the flow field inside the pump and studying its performance. This study includes modeling the pump using a commercial CAD package, GAMBIT and a 3-D computational fluid dynamic (CFD) solver, FLUENT. The calculation employs both the simplified steady moving frame and the complicated transient sliding mesh schemes. The flow pattern, static pressure distribution, and total pressure losses are calculated and analyzed. The regions of high total pressure losses and potential creation of cavitation are identified. Design changes are recommended to minimize cavitation and total pressure losses to improve the pump performance.

An improved valve mechanism for the solar motor developed by the Solar Pump Corporation was developed to overcome weaknesses discovered in earlier tests. Va17e actuation was changed from parallel to perpendicular to the motion of the piston to facilitate valve adjustment and cc free the valve seals from being compressed by the main spring. Inlet and outlet valves were replaced with purchased check valves to reduce machining requirements. Mechanical efficiency of the modified motor was found to range from 0.23 to 0.34 and thermodynamic efficiency from 0.027 to 0.032 in a day-long test. Overall energy conversion efficiency was computed to be 0.008 at noon when pumping with a head of 8.25 m. The modified valve mechanism met design objectives of requiring simpler manufacturing processes, and simple and minimal servicing. The manufacturing cost is estimated to be less then $2000.00 for the solar motor.

In the vehicle industry it is of great interest to reduce the emissions and lower the fuel consumption.Up to now a lot of effort has been put into increasing the efficiency of the engine,but it starts to get expensive to keep improving the engine. In this master thesis the transmissionand especially the oil supply to the transmission is investigated. An example of how the requirements of an oil pump can be decided is described. Knowingthe requirements different pumps may be adapted to meet the demands. The gear pumpused today is compared with a variable displacement pump and an electric pump. The gearpump is not possible to control, but the other two are. A few simple control strategies areintroduced. The strategies are implemented and the three pumps are used in the same drivecycle. It is shown that it is possible to reduce the energy that the pump requires if it isreplaced by a variable vane pump or an electric pump.

Due to the increasing demand, nonclog type sewage pumps are designed and manufactured in large amounts all over the world. However, a methodology on the design of these special duty pumps is not encountered in the literature. Therefore, the manufacturers tend to develop their own empirical methodologies. In this thesis, a nonclog pump is designed and constructed on the basis of suitable approaches of known centrifugal pump design methods. In this frame, a nonclog type submersible pump that is capable of handling solids, up to a diameter of 80 mm is aimed to be designed. The designed pump delivers 100 l/s flow rate against a head of 24 m. The rotational speed of the pump is 1000 rpm. Design procedure and the important points that differ nonclog pump design from standard centrifugal pump designs are given. In addition, hydraulic characteristics of two nonclog pumps, one of which is the pump designed in this study, are investigated by means of computational fluid dynamics (CFD) code. The designed pump is manufactured and tested in Layne Bowler Pump Company Inc. The test result indicates that design point is reached with a deviation in the limits of the related standard. Wire to water total best efficiency obtained by the test is 60%. Close agreement between results of actual test and numerical experimentation performed by CFD code shows that CFD analysis is a quite useful tool in predicting the hydraulic characteristics of nonclog pumps. Moreover, the pump is tested at 750 rpm and the test results are found to be in good agreement with the similitude anaysis results.

Detta projekt är ett examensarbete på 15 poäng inom Innovations och Designingenjörsprogrammet på Karlstads Universitet, utfört under våren 2006.

Målsättningen med projektet var att hitta en form på insulinpumpen som tilltalar unga användare och dessutom minskar känslan av medicinskt hjälpmedel. Vi bestämde oss för att ge den ett utseende som mer liknar annan teknisk utrustning som finns på markanden idag. Detta som en väg att försöka höja ungdomars motivering till att övervaka och behandla sin diabetes.

Vid intervjuerna framkom det att många unga hade problem med bärandet av pumpen. Dagens pump upplevs för stor och klumpig eftersom de ofta vill gömma den i/under kläderna. Som ett resultat av denna information så valde vi att dela pumpen i två mindre enheter. Pumpenheten, som är kopplad till kroppen, kan liknas vid en MP3-spelare, och fjärrkontrollen, som innehåller den mesta intelligensen, både ser ut som och fungerar som en armbandsklocka.

Klockan har också inbyggd kontinuerlig övervakning av blodsockervärdet utan stick. Vilket var ett av de vikigaste önskemålen från användarna.

Med detta koncept kan ungdomarna välja om de vill dölja pumpen, eftersom den är så pass liten, eller om de vill ha den synlig, eftersom den ser ut som annan teknisk utrustning som bärs på kroppen.

This project is an examination project for 15 points at the Innovation and design engineering program, carried out at Karlstad University during spring 2006.

The purpose of this project is to find a shape that addresses young people and to minimize the medical aid stamp of the pump. We decided to give the pump an appearance more similar to other electronic devices on the market today in order to increase the motivation of treating and monitoring your diabetes.

During the interviews we found out that, youngsters hade problems related to the pump carrying. The pump of today is a bit too big and clumsy for young people who often want to hide it. As a result of this information we divided the pump into two smaller units. The pump unit that is connected to the body looks a bit like an MP3 player, and the remote control, where the intelligence lies, both looks and works like a watch.

The remote also has integrated glucose monitoring that is non-invasive. This was one of the top priorities on the wish list of the users.

With this concept the youngsters can choose whether they want to hide it, since it is small enough to hide in the pocket, or to show it off for their friends, as it could pass for a portable device.

Over the past several years, there has been significant development in the field of applications for piezoelectric materials. This thesis focuses on using these materials in a piezohydraulic pump system. Piezopump systems typically operate by pushing fluid through check valves to produce positive fluid flow. The accompanying hydraulic system utilizes a control valve, hydraulic accumulator, and hydraulic actuator. The function of the piezopump is to convert the very small displacements of the piezoelectric stack actuators into useful work. This paper details the design, construction, and testing of four such possible pumping systems. The first system was a thin diaphragm piezo pump which utilized conventional check valves to rectify the flow. This pump was the next generation system in a series of piezopumps designed at Georgia Tech. Its peak performance with a driving voltage of 150V was a flowrate of 140 cc/min with a blocked pressure of 1.38 MPa (200 psi.). The key features of this system were its aluminum construction and ease of assembly. A new technology was developed which used a resonant fluid cavity to build usable pressure for a pumping system. Two half wave resonators were build to operate at frequencies of 20 kHz and 1 kHz. These systems produced good pressure during resonance, but attempts to rectify these high frequency pulses were unsuccessful. Rectification methods such as reed valves, vortex fluid diodes, and nozzle/ diffuser arrangements were discussed. A reed valve system was developed and tested. A fourth piezoelectric system was developed which used the driving elements and the reed valves originally designed for the resonant systems. This non resonant reed valve pump produced good results. This pump systems produced 338cc/min at a frequency of 400 Hz. It also produced a blocked pressure of 250 psi. There are many applications for these miniature high flow pumping systems. The technology in the reed valve pump is scalable, and the size of this particular system may be reduced dramatically to offer even more space saving potential.

Implantable rotary blood pumps (RBPs) are an emerging technology designed to provide sufferers of heart failure with a viable treatment option which improves their medical prognosis and quality of life. The broad aim of this thesis is to address the need for a pump control strategy, and develop a solution whereby the implant recipient??s physiological requirements are continuously monitored in a non-invasive manner and met with an appropriate response by the RBP. Employing only the non-invasive signal of instantaneous pump impeller speed to assess flow dynamics, five physiologically significant pumping states have been identified in acute ex vivo porcine experiments (N=6). Two broader states, corresponding to normal and ventricular suction conditions, were readily discernable in clinical data from human implant recipients (N=10). Employing a classification and regression tree (CART) model, an automated real-time algorithm was developed to detect pumping states with a high degree of sensitivity and specificity. Both suction and normal states were detected without error in data from the animal experiments, and with a peak sensitivity/specificity, for detecting suction, of 99.11% / 98.76% in the human patient data. Algorithms to non-invasively estimate RBP flow and differential pressure in both steady- and pulsatile-flow environments were developed. Taking the pump feedback signals of speed and power, together with the blood haematocrit (or equivalent viscosity) level, as input parameters, several estimation models were developed via polynomial surface fitting and/or system identification methods, yielding clinically acceptable results (mean flow errors of 3.09% and 5.49%, and mean pressure errors of 1.80% and 6.47%, for the steady- and pulsatile-flow cases, respectively). An RBP control algorithm based on a non-invasive indicator of the implant recipient??s activity level has been proposed and evaluated in a software simulation environment. An Activity Level Index (ALI) forms the basis of an adaptive control module operating within a hierarchical multi-objective framework which imposes several constraints on the pump??s operating region. Three class IV heart failure cases of varying severity were simulated under rest and exercise conditions, and a comparison with other popular RBP control strategies was performed. Simulations of the proposed control algorithm exhibited the effective intervention of each constraint, resulting in an improved flow response and the maintenance of a safe operating condition, compared with other control modes.

The objective in this Master's Thesis was to verify the stability criteria for a centrifugal pump. Operation of an unstable pump may lead to either exponential or oscillatory unstable behavior of both pressure and volume flow of the water in the conduit system. This is of course unwanted, and fulfilling the stability criteria is desirable. The idea is to test an unstable pump, which was done at the Technical University Berlin (TU) in Germany. Most of the test set-up was already installed, but a new pump and a pressure accumulator was inserted. Unfortunately the experiment was not able to verify the stability criteria systematically, because the set-up was a closed loop without reservoirs; and because the different parameters affecting the stability were difficult to change. The experiment was educational even though the stability criteria were not verified. Different tasks were executed at TU, like installing the pressure accumulator and a pressure sensor, and measuring the pump characteristic. The work with the Master's Thesis also improved the candidate's understanding of the stability criteria and the dynamic behavior of the water in general.A simulation program was made in Matlab, and the aim of the program was to simulate the oscillations of the water in the conduit system. Most of the parameters put into Matlab were measured at TU, except the volume of the air inside the pressure accumulator. This volume affects the frequency of the oscillations a lot, but a good estimation of the volume of the air, made the simulations quite similar to the measured results. In addition to simulating the existing set-up, the simulation program made it easy to vary the parameters affecting the stability criteria. The simulation program was tested this way, and the stability criteria seem to be correct.

Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2012.
Cataloged from PDF version of thesis.
Includes bibliographical references (p. 66).
In medical emergencies, an oxygen-starved brain quickly suffers irreparable damage. In many cases, patients who stop breathing can be resuscitated but suffer from brain damage. Dr. John Kheir from Boston Children's Hospital created a compressible fluid that can re-oxygenate blood quickly in patients with asphyxia and cardiac arrest. Because the fluid is compressible, the set infusion rate on an ordinary pump does not necessarily indicate what is delivered. In addition, the fluid is provided at a 90% gas by volume concentration and is extremely viscous. The goal of this project is to create a pump to deliver a specified volumetric flow rate of the oxygenated fluid created by the doctor. The pump design uses a bellows with force feedback calibration to pump 1 liter of fluid over 5 minutes and mix the concentrated 90% form with saline without degradation to form a 70% concentrated form with the viscosity similar to that of blood. My part in the project was to create the control system that would drive the pump using a force feedback and to optimize the design of the pump The oxygenated fluid pump built can successfully store and dispense one liter of fluid, mix the concentrated form of the oxygenated fluid with saline, maintain sterility, and preserve the fluid's properties, all in a cost appropriate manner. It is a modular design that can easily be modified to improve its performance. Further testing is required to tune the control system and ensure that the flow rate is accurate to ±10%. The pump is mostly being used as a research tool in order to run tests that will help characterize the fluid and later can be used for small and large animal testing.
by Bruno Aiala Piazzarolo.
S.B.

Thesis (MEng)--Stellenbosch University, 2015.
ENGLISH ABSTRACT: The water utilized by passive air-conditioning systems in buildings is typically required at higher elevations. The thermally driven natural circulation water pump (TDNCWP) is a passively driven pumping system for delivering water from ground level against gravity to a higher elevation. It consists of a humid air closed duct loop to which a temperature difference is applied, resulting in a density gradient driven flow. A hot water evaporation tray inside the loop at ground level introduces water vapour to the loop air flow, and a cold condensation plate inside the loop at the elevated level removes this water vapour for passive airconditioning usage. In this thesis, a one-dimensional theoretical and numerical simulation model is developed. Experiments were conducted on two experimental TDNCWP set-ups of different cross sectional areas to evaluate the pump design and the theoretical model. It is shown in this thesis that the TDNCWP can provide water at varied elevations using non-mechanical, passive means. A temperature difference of 9 to 12.5 °C induced an average velocity of 0.4 to 0.6 m/s for a duct cross section of 100 mm2. For a larger cross section of 400 mm2, a temperature difference of 2 to 5 °C induced an average velocity of 0.25 to 0.3 m/s. An asymmetrical velocity profile was observed which varied at different points in the loop. A water delivery rate of 1.2 to 7.5 L/day was experimentally determined which compares well to the passive air-conditioning water requirements of a small building. The theoretical model over-predicted the delivery rate at increased duct cross sectional areas but fared well when compared to the smaller experimental model results. Further refinement of the numerical model and the TDNCWP design is required, and recommendations were made regarding this. It is clear however that the TDNCWP provides an alternative to a conventional water pump for low-volume water pumping requirements.
AFRIKAANSE OPSOMMING: Die water wat gebruik word deur passiewe lugversorgingstelsels in geboue word tipies benodig op hoër vlakte. Die termies gedrewe natuurlike sirkulasie waterpomp (TDNCWP) is ʼn passiewe gedrewe pomp stelsel vir die lewering van water vanaf die grondvlak teen swaartekrag na ʼn hoër vlak. Dit bestaan uit 'n vogtige geslote lug geut siklus waarop ʼn temperatuur verskil toegepas word, dit lei tot vloei gedrewe deur ʼn digtheids gradiënt. ʼn Warm water verdampings-pan binne die geut op grondvlak stel waterdamp aan die geut lugvloei toe, en ʼn koue kondensasie plaat binne die geut op die verhoogde vlak verwyder hierdie waterdamp vir passiewe lugversorgings gebruik. In hierdie tesis word ʼn eendimensionele teoretiese en numeriese simulasie model ontwikkel. Eksperimente is uitgevoer op twee eksperimentele TDNCWP stelsels van verskillende deursnee grootes om die pomp ontwerp en die teoretiese model te evalueer. Die tesis dui aan dat die TDNCWP water kan voorsien teen verskillende hoogtes op ʼn nie-meganiese, passiewe wyse. ʼn Temperatuur verskil van 9 tot 12.5 °C veroorsaak ʼn gemiddelde snelheid van 0.4 tot 0.6 m/s vir ʼn geut deursnit van 100 mm2.Vir ʼn groter deursnit van 400 mm2, het ʼn temperatuur verskil van 2 tot 5 °C ʼn gemiddelde snelheid van 0.25 tot 0.3 m/s veroorsaak. ʼn Asimmetriese snelheidsprofiel was waargeneem wat gewissel het op verskillende punte in die siklus. ʼn Water voorsienings tempo van 1.2 tot 7.5 L / dag was eksperimenteel waargeneem wat goed vergelyk met die passiewe water lugversorging vereistes van 'n klein gebou. Die teoretiese model het ʼn groter voorsienings tempo voorspel vir die groot deursneë, maar het goed gevaar in vergelyking met die kleiner eksperimentele model. Verdere verfyning van die numeriese model en die TDNCWP ontwerp word vereis, en aanbevelings is gemaak ten opsigte van hiervan. Dit is egter duidelik dat die TDNCWP ʼn alternatief is vir konvensionele lae-volume water pomp applikasies.
National Research Foundation (NRF)

The digital displacement hydraulic piston pump is a hybrid device which combines a microcompressor with an established form of high-pressure pump to create a highly integrated machine which can produce a variable high-power output directly from an electronic command. The actively controlled inlet poppet-valve in each cylinder can be held open against the discharging flow in order to disable it during a single cycle. Cylinders can be disabled in this manner, following a maximally smooth sequence, allowing a controlled output flow to be achieved. A compliant device located near the pump, such as an accumulator, provides time-averaging of the flow pulsations in order to minimise the effects of the quantisation error caused by cylinder disabling. The advantages of this approach over the conventional variable-swash axial piston pump lie with both the response speed and the inherent energy efficiency of real-time cylinder selection. Disabling cylinders in this way restricts parasitic losses to very low levels since unused cylinders are not pressurised nor do they incur loads on their associated bearings. The response time of the pump is related to shaft speed, with the pump able to attain either full or zero output from any starting condition, in less than a single shaft revolution. At induction motor speeds this allows large-signal response times of the same order as those achieved by commercial proportional valves. The thesis chronicles the development of the Digital Displacement pump. It begins with the formulation of a simulation model which is able to predict the behaviour of the machine in both flow and pressure control modes. The valve control possibilities are then explored and the design of active valve latches using finite-element analysis described. The sinusoidal flow forces on the disabled poppet are evaluated through a large range of experiments and the results condensed into parametric equations useful for predicting the valve latching requirements of most machines. The mechanical and electronic hardware design, leading to the construction of the prototype, is then discussed.

Vid gruvdrift krävs det att grundvattnet pumpas undan och det görs med hjälp av ett system av pumpar placerade i utsprängda sumpar där vatten samlas. Dessa gropar är stora och dyra att tillverka och de lider ofta av problem med sedimentering. När en tunnel inte längre används fylls denna ofta igen med sten och allt arbete och alla pengar som lagts på att spränga ut dessa gropar går förlorade. Detta har lett till att Xylem vill testa ett koncept med en mobil pumpsump som kan återanvändas på en annan plats.Denna rapport beskriver processen där ett koncept för en mobil pumpsump har utvecklats med utgångspunkt från Xylem’s produktserie TOP. TOP-serien består av prefabricerade självrensande pumpsumpar avsedda för avloppsnät. Sumparna är designade för att grävas ned i marken och när sumpen är nedgrävd sker all åtkomst till sumpen ovanifrån via en servicelucka.En simulering av en serie sumpar utfördes för att undersöka vad som var en lämplig sumpvolym och när denna var bestämd modifierades övriga delar av sumpen för att passa ändamålet. Utöver detta designades en mobil enhet att montera sumpen på. Denna enhet innehåller bland annat en serviceplattform och en skyddsram och den möjliggör även lyft med gaffeltruck.
In mining it is required that the ground water is pumped away and it is done by a system of pumps placed in blasted sumps where water is collected. These pits are large and expensive to make and they often suffer from problems with sedimentation. When a tunnel no longer is being used it often refilled with rocks and all the work and money put into blasting the sumps is lost. This has led to that Xylem wants to test a concept with a mobile pump sump that can be reused in another location.This report describes the process where a mobile pump sump has been developed whit starting point from Xylem’s product series TOP. The TOP-series consists of prefabricated pump sumps intended for sewage systems. The sumps are designed to be placed under the ground and when they are buried all access is given from above via a service hatch.A simulation of a series of pumps was made to investigate what an appropriate sump volume would be and when that was decided the other parts of the sump was modified to suit the intended purpose. In addition to this a mobile unit on which the sump is mounted was designed. This unit includes a service platform and a protective frame and it also enables lifting with a forklift.

Bibliography: pages 112-118.
The study describes the development of a prototype solar energy powered water pump. The system was developed in an attempt to meet the following requirements and constraints: Cheap, convenient and easy manufacture, reliability and low maintanance of the system, no auxiliary power requirements, and minimum running costs. The literature survey indicated that a number of pumping systems have been studied in the past, with variable successes, based on numerous thermodynamic cycles. Our system operates on the combination of two constant volume and two constant pressure processes, on a working fluid which expands due to input heat from the sun, and contracts due to heat rejection to the pumped water. This expansion and contraction of the fluid is utilized to move flexible bellows, resulting in the pumping action. The thermodynamic and heat transfer aspects of the system have been modelled and the results were compared with the experimental data. A number of working fluids were attempted and the final results show very good agreement between the theoretical and experimental results for Freon 113. Lack of detailed thermodynamic data did not allow similar comparison for Methanol. Yet, experiments on another fluid (Cyclohexane) were abandoned because the fluid was found to be incompatible with the bellows material.

The study of photovoltaic materials is important so as to develop new solar energy technologies: in particular, quantum-confined semiconductors could offer increased quantum efficiencies at a much lower manufacture cost. This thesis contains results from a number of pump-probe experiments designed to probe the carrier dynamics in bulk and quantum-confined photovoltaics. A THz time-domain spectrometer was designed, built and commissioned. The THz refractive indices and absorption coefficients of toluene and hexane were determined, and the spectrometer was benchmarked using a photoexcited GaAs wafer. Results are presented of time-resolved THz spectroscopy of photoexcited bulk InP as a function of laser excitation wavelength. These data were used to extract the quantum efficiency of bulk InP in order to compare with recent results for InP quantum dots. The quantum efficiency in quantum dots increases when the incident photon energy is at least twice the band gap energy, whereasthe efficiency of the bulk material is found to decrease. This is because of surface recombination, and these measurements therefore verify the potential superiority of quantum dot materials over bulk materials for use in solar energy applications. Initial measurements of quantum dots using THz spectroscopy highlighted the various experimental challenges involved and the upgrades required to study such samples in the future.The time-dependence of the photoinduced surface photovoltage (SPV) in Si was studied on nanosecond timescales by synchronizing an ultrafast laser system to a synchrotron radiation source (the SRS at Daresbury, UK), and measuring the resulting shift in the photoelectron spectrum. The equilibrium band bending was determined, and the decay of the SPV was attributed to the recombination of charge carriers across the band gap. Results are presented for the SPV in bulk ZnO and for PbS quantum dot chemically attached to ZnO. The fact that the PbS quantum dots were chemically attached to the surface without becoming oxidized was verified using X-ray photoelectron spectroscopy (XPS). The changes caused by photoexcitation occur on much longer timescales in ZnO than Si (sub-milliseconds rather than nanoseconds), and these timescales were conveniently accessed using the time-resolved XPS facility at the TEMPO beamline at Synchrotron SOLEIL (Paris, France). This is due to oxygen adsorption and desorption processes at the ZnO surface affectingthe transfer of charge carriers. The addition of PbS quantum dots to the ZnO surface was found to increase the speed of this charge transfer due to injection of carriers directly from the PbS quantum dot to the bulk ZnO conduction band.

At the end of January 2021, an important page in financial history was written for the records as a moment in which private investors attacked hedge funds. The operation "headquarter" was Wallstreetbets, a forum of people looking for high return investments and it played a central role in the GME rally. From an economical perspective, the main reason of the exponential increase of the stock price is Short-squeeze; to make it happen, what is need is pressure from the market. This research focused on finding a relationship between activity on the Reddit platform and the change in GME stock price. Many different analysis were used, starting with a Sentiment analysis measuring the similarity beten different NLP dictionaries and verbiage within the Reddit platform. Lastly, a Fama and French model was run to find whether or not, there was an economical reason behind the return amounts for this event. Relevant data was found from all the tests conducted and the result led to believe that this event was a pump and dump scheme.

Insulin pumps are designed for the self-management of diabetes mellitus in patients and are known for their complexity of use. Pump manufacturers engage trainers to teach patients how to use the devices correctly to control the symptoms of their disease. Usability research related to insulin pumps and other infusion pumps with first-time users as participants has centered on the relationship between user interface design and the effectiveness of task completion. According to prior research, the characteristics of system behavior in a real life environment remain elusive. A suitable approach to acquire information about potential usability problems encountered by first-time users is to obtain this information from the health care professionals who train them. The purpose of the study was to discover the lived experiences and shared impressions of insulin pump trainers during training sessions with first-time users. Interpretative Phenomenological Analysis (IPA) was used to uncover the phenomena associated with usability challenges that first-time users of insulin pumps face when learning to use the device. Six participants representing a homogeneous sample were recruited from a wide geographic area in the United States, and semi-structured interviews containing open-ended questions were conducted with the respondents. The data from the lived experiences and shared impressions of the participants were used to develop the following five super-ordinate themes: Emotion-charged Environment, Personalized Training, Safety Issues and Disaster Planning, Professional Dedication, and The Voice. The essence of participants’ experience was described around the pivotal moment when the training sessions are successfully completed and insulin pump therapy becomes alive. The findings of this study have implications for information systems professionals who conduct research on the safe design and usability of safety critical medical devices. In addition, the findings from this study create opportunities for practice to improve the initiation of insulin pump therapy in patients with diabetes.

The current generation of Airbus long-range civil transport aircraft actively control the centre of gravity of the aircraft by adjusting the fuel distribution between the horizontal tail surface and the forward tanks in order to minimise cruise drag. Here, it is proposed that the current on-off control method could be replaced by a variable flow rate, provided by a variable speed centrifugal pump. The impacts of this at the aircraftlevelintermsof cruisefuelburnreduction,valveoperationcycle reductionand power consumption are investigated here using an extension to an existing fuel system simulationpackage and ageneric aircraftfuel systemdefinition. Itis shownthat using such a control system reduces fuel burn and the number of valve cycles, which could translate into a reduction in operating costs. The benefit of changing the controller to use tailplane trim angle directly rather than inferred centre of gravity position is assessed, and is shown to further reduce the fuel burn. It is suggested that such centre of gravity could provide significant benefits over the existing method. Steady-state anddynamic models ofcentrifugalpumps,ACinductiondrives andtypical aircraft fuel system pipework components are developed. These are validated against experimentaldatafrom a test rig of a representative system. Test rig simulation results areshowntoagreewell with thosefromexperimentation. Anewsecondary noisesource is developed for the dynamic analysis of the centrifugal pump, and a new acoustic experimental method is developed for the prediction of fluid inductance in pipework components. The results are compared against an existing CFD based method and showgood agreement. Thenewmethod representsamuch simplerexperimental means of determining the effects of fluid inertia than the existing secondary source method. Itisdemonstrated thatthedynamicbehaviourof thecentrifugalpumpis, asexpected, insignificant when considering systems containing long pipes, and that steady-state pump models are sufficient for analysing their behaviour. Thepumpmodels aregeneralisedby non-dimensionalisation,in order to maximise their applicability to analysis of aircraftfuel systems. They are applied to ageneric aircraft fuel system simulation, in order to model the behaviour of the system during a trim transfer. Thisisused todemonstratethe application of theproposed variable flowrate trim control system. The results of these simulations agree well with those used to demonstratethebenefitsof thecontrol systemattheaircraftlevel. Conceptsof system health monitoring tools are discussed with reference to the system simulations.

En el ámbito de la Oleohidráulica, las bombas de pistón poseen los diseños más sofisticados, de hecho, las bombas de pistones son las únicos capaces de trabajar a altas presiones, además de poseer el mejor rendimiento de todo el grupo de bombas existentes. Sin embargo, cabe señalar que todos los diseños de las bombas de pistón, se basan principalmente en la experiencia de los diseñadores, por lo tanto no existen herramientas matemáticas para optimizar el diseño de las diferentes partes de las bombas. Por otra parte, en la actualidad hay empresas como Oilgear Towler, que inserta ranuras (surcos) en los patines deslizantes y en los pistones, (dos partes principales de estas bombas), pero no hay ningún estudio científico para analizar sus ventajas o desventajas. Por lo tanto, es necesario comprender matemáticamente las ventajas y desventajas debido a la presencia de ranuras en la superficie de diferentes partes de la bomba. Hay cuatro superficies de deslizamiento en las bombas de pistones, plato inclinado patín deslizante, barrilete y placa de cierre, pistón cilindro y junta esférica entre pistón y patín deslizante. Lubricación entre estas superficies es necesaria, apareciendo por tanto fugas de fluido a bombear entre las mismas. En este proyecto, nuestro objetivo es analizar cada una de estas diferentes superficies de deslizamiento por separado para comprender su diseño y el efecto de los parámetros de diseño en el comportamiento de la bomba. Una vez se tenga un buen entendimiento de las diferentes partes de la bomba de pistones, el objetivo es modelar el comportamiento dinámico de la presión y flujo en la salida de la bomba. En concreto se ha realizado: Conjunto plato inclinado, patín deslizante – Estudio de las características estáticas y dinámicas del patín deslizante, incluyendo la ranura tallada en el patín. Las ecuaciones de Navier Stokes en coordenadas cilíndricas se han aplicado entre el patín y el plato incluyendo la ranura. Los resultados presentados en este trabajo contemplan, distribución de la presión, las fugas de fluido, la fuerza y par sobre el patín, se ha estudiado la variación de dichos parámetros al modificar las dimensiones y posición de la ranura. El comportamiento dinámico del patín se ha tenido también en cuenta. Se estudia la posición de la ranura con el fin de optimizar el comportamiento del patín. Barrilete, placa de cierre.- Se analiza mediante la simulación de las ecuaciones de Reynolds de lubricación por FDM (método de diferencias finitas), la distribución de presiones, las fugas, la fuerza y los pares entre el barril y la placa de cierre. La fuerza total y los pares de torsión sobre el barril, se evalúan partiendo de la presión simulada, mostrando que los pares dinámicos que existen sobre el eje XX son mucho menores que los pares actuantes sobre el eje YY. . Pistón cilindro - Se ha investigado el comportamiento del pistón mediante la modificación del número de ranuras y su posición, la distribución de la presión en el intersticio pistón-cilindro, la fuerza sobre el pistón, las fugas y el par de torsión que actúa sobre el pistón se han analizado. También las zonas donde la cavitación es probable que aparezca se han presentado, se discute la forma de prevenir la aparición de cavitación a través del uso de ranuras. La ecuación de lubricación de Reynolds se ha modelizado en el intersticio pistón-cilindro mediante el uso de volúmenes finitos, la excentricidad y el movimiento relativo pistón-cilindro se han considerado. Diferentes configuraciones de ranuras han sido evaluadas con el fin de encontrar mínimas fugas, máximo par y mínima aparición de cavitación. Se especifican instrucciones de diseño para optimizar el comportamiento del pistón. Modelo dinámico de la bomba.- Se ha presentado un amplio conjunto de ecuaciones explícitas para cada parte con movimiento relativo de la bomba de pistones. Todas las ecuaciones se han validado mediante un análisis numérico y en su caso experimental. Las ecuaciones han sido combinadas para estudiar de forma dinámica las perturbaciones de presión y el caudal de fugas. El efecto de la pulsación de caudal cuando se modifica el diseño de la bomba también es presentado. En esta tesis, un modelo de simulación basado en ecuaciones analíticas se ha desarrollado, modelo que produce resultados muy rápidamente y aclara con mucha precisión el efecto de las fugas a través de los diferentes intersticios de la bomba.
In the field of Fluid Power, piston pumps possess the most sophisticated designs, in fact, pistons pumps are the only ones capable of working at high pressures, besides possessing the best performance (efficiency) of the entire group of existing pumps. However, it is noted that all the designs of piston pumps, are mostly based on the experience of the designers, thus there exist no mathematical tools for optimizing the design of the different parts of the pumps. On the other hand, there are now companies like Oilgear Towler, who inserted slots (grooves) in the slippers and in the pistons, (two major parts of these pumps) but there is no scientific study to analyze its advantages or disadvantages. There is therefore a need to understand mathematically to study the advantages and disadvantages due to the presence of the groove on the surface of different pump parts. There are four sliding surfaces in the piston pump, Slipper-swash plate gap, Barrel-valve plate gap, Piston-barrel chamber gap and Spherical bearing, where lubrication exists and leakages through these channels occur. In this project, our aim is to analyze each of these different sliding surfaces separately to understand its design constrains and the effect of the design parameters on the pump behavior. After having a better understanding of all the different parts of the piston pump, the aim is to model the dynamic behavior of pressure and flow at the outlet of the pump. Slipper plate gap - To understand static and dynamic characteristics of a piston pump slipper with a groove. Three dimensional Navier Stokes equations in cylindrical coordinates have been applied to the slipper/plate gap, including the groove. The results presented in this thesis include, pressure distribution, leakage, force and torque variations when groove dimensions and position are being modified, the effect of slipper tangential velocity and turning speed are also considered. Design instructions to optimize slipper/groove performance are also given. Barrel-valve plate gap - Present thesis, analyses the pressure distribution, leakage, force and torque between the barrel and the port plate of an axial piston pump by simulating Reynolds equations of lubrication by FDM (finite difference method). The overall mean force and torques over the barrel are evaluated from simulated pressure and it shows that the torque over the XX axis is much smaller than the torque over the YY axis. A detailed dynamic analysis is then studied by using the temporal torque calculated by Bergada. Piston-barrel chamber gap - It is being investigated the piston performance by modifying the number of grooves and their position, pressure distribution in the clearance piston-cylinder, leakage force and torque acting over the piston will be discussed, also the locations where cavitation is likely to appear will be presented, discussing how to prevent cavitation from appearing via using grooves. A finite volume based Reynolds equation model has been formulated for the piston-cylinder clearance which considers the piston eccentricity and the relative tangential movement between piston and barrel. Different configurations of the grooves have been evaluated in search of finding minimum leakage, minimum appearance of cavitation and maximum restoring torque. Design instructions to optimize the piston behavior are also given. Full pump Model - An extensive set of explicit equations for every pump gap will be presented. All of the equations will be checked via performing a numerical analysis of the specified pump clearance, the equations will then be combined to study dynamically pressure ripple and leakages. The effect on the flow ripple when modifying the pump design will also be presented. Therefore in present thesis, a simulation model based on analytical equations has been developed which produce very fast results and clarify very precisely the effect of different leakages happened through the pump clearances.

Examensarbetet har utförts på Johnson Pump AB i Örebro och behandlar tillverkningen av marina kylvattenpumpar. På den allt mer globala pumpmarknaden har konkurrensen blivit hårdare och Johnson Pump har märkt ökade krav på främst kostnadseffektivitet och leveransprecision. Samtidigt efterfrågas ett brett sortiment. I dagsläget har man dock problem med långa ledtider och höga lagernivåer, varför man på senare tid har ställt frågan om det bästa vore att kundorderstyra tillverkningen inom det marina affärsområdet. Syftet med arbetet är därför att undersöka möjligheterna att övergå till en högre grad av kundorderstyrd produktion och se vilka konsekvenser detta skulle medföra på kostnader och leveransservice.

För att det ska bli möjligt för Johnson Pump att tillverka pumphus mot kundorder, måste planeringen bli tydligare och mer strukturerad. I dagsläget är produktionsledtiderna för långa och framförallt för osäkra, för att kunna ha en kundorderstyrd produktion. Den viktigaste åtgärden blir därför att reducera ledtiderna. Kortare ledtider minskar kapitalbindning i PIA, gör produktionen mer flexibel, och minskar variationer och störningar. Såväl marknads-, produktions- och produktkarakteristika tillåter en förflyttning av kundorderpunkten längre bak i flödet. Slutsatsen är således att Johnson pump har goda möjligheter till kundorderstyrning av produktionen, under förutsättningen att nya planeringsmetoder införs för att uppnå kortare och stabilare ledtider.

De viktigaste punkterna i föreslagen planering, är att ha färre tillverkningsorder igång samtidigt och att minska partistorlekarna. Planeringssituationen är mer komplex i den mekaniska verkstaden än i monteringen, där man även har större volym- och produktmixflexibilitet. Därför ska produktionen pushstyras utifrån den mekaniska verkstaden med hjälp av MRP-systemet. För att göra systemet mer pålitligt och säkerställa att det verkligen används, måste det uppdateras kontinuerligt. Materialflödet mellan arbetsstationer bör vidare bli mer direkt och mellanlagring bör elimineras. Med ett stort antal artiklar i kraftigt varierande efterfrågevolymer, måste man förenkla planeringssystemet och samtidigt anpassa produktionen så den bättre följer marknadsefterfrågan. En ABC-klassificering delar in artiklarna i mer homogena grupper för differentierad styrning av varje artikelklass.

Resultatet av den nya planeringen är en ledtidsreduktion på i genomsnitt 83 procent. De kortare ledtiderna ger, förutom en minskning i bundet kapital, även högre produktmix- och volymflexibilitet, vilket i sin tur ger Johnson Pump fler strategiska valmöjligheter. Det sätter företaget i en bättre position inför ökade krav på kortare leveransledtider och tätare leveranser, samtidigt som kostnaderna sänks. Genom att tydliggöra effekterna av ledtids- och ställtidsreduktioner, vilka tidigare doldes av stora produktionsserier, skapas dessutom incitament till förbättringsprogram som på sikt kan öka Johnson Pumps konkurrensfördelar.

The master thesis has been carried out at Johnson Pump AB in Örebro and deals with the manufacture of marine cooling pumps. The competition has hardened on the increasingly global pump market and Johnson Pump has noticed greater demands principally for cost-efficiency and delivery performance. At the same time a broad product-mix is requested. In the present-day situation the company experiences problems with long lead-times and high levels of inventory, wherefore lately the question has been raised whether it would be better with a make-to-order strategy for the marine business area. The purpose of the thesis work is therefore to examine the possibilities of moving towards a higher degree of customer-order-driven production and to look into which consequences this would have on costs and the customer service elements.

To enable make-to-order production of pump bodies at Johnson Pump, the planning and control must be more distinct and structured. Today the production lead-times are too long, but above all too uncertain, to make a customer-order-driven production possible. The most important measure in order to achieve this is therefore reduction of lead-times. Shorter lead-times decrease capital tied up in WIP, make the processes more flexible, and reduce variation and disturbances. Market, production and product characteristics allow a relocation of the customer order decoupling point further back in the production flow. The conclusion is hence that Johnson Pump has good chances of a customer-order-driven production, under the condition of a new planning system to achieve shorter and more stable lead-times.

The main points in the proposed planning system are to have fewer production orders running simultaneously and to have smaller batch sizes. The planning situation is more complex in the mechanical workshop than in the assembly, where, in addition, the volume and product-mix flexibility is greater. Therefore the production ought to be controlled with a push strategy from the workshop with the help of the MRP-system. The business process software should also be updated continuously to ensure its accuracy and usage. The material flow between workstations should further be more direct without buffers. With a large number of stock-keeping units in greatly varying demand volumes, the planning system must be simplified and the production brought in line with market demand. An ABC-classification divides the items into more homogenous groups for differentiated planning and control of each class.

The result of the new planning system is a reduction of lead-times by 83 percent on average. The shorter lead-times give, apart from a reduction in capital tied up, also higher product-mix and volume flexibility, which in turn gives Johnson Pump more strategic opportunities. It puts the company in a better position to respond to raised requests for shorter delivery lead-times, while costs are lowered. Through making the effects of lead-time and set-up-time reductions more evident, which before was concealed by large production series, an incentive for starting an improvement program is created. This can, in the long run, increase Johnson Pump’s competitive advantage.

I detta exjobb har en testplattform skapats för att kunna testa, utvärdera och jämföra olika pumpstyrningar i torr miljö. Testplattformen består av en simulerad pumpstation till vilken befintliga pumpstyrningar av valfri modell kan kopplas, det vill säga ett Hardware-In-the-Loop-system. De främsta fördelarna med en sådan plattform är flexibilitet, snabb feedback samt möjligheten att återskapa exakt samma förutsättningar för olika pumpstyrningar. Testplattformen har implementerats i LabVIEW på en PC som kommunicerar med pumpstyrningshårdvara via ett I/O-kort för analoga och digitala signaler. Det simulerade systemet konfigureras genom val av bland annat pumpar, pumpsump, inflöde och rörsystem. Utifrån de inmatade värdena och styrsignaler från pumpstyrningen simuleras sedan bland annat systemets flöden, energier och temperaturer. Nivån i sumpen, och övriga insignaler till pumpstyrningen, återkopplas från simuleringen. Det finns även möjlighet att påverka systemet genom att applicera exempelvis ett pumphaveri eller en igensättning. Testplattformen har testkörts mot tre olika pumpstyrningshårdvaror. Testkörningarna visar att både simuleringsmodellerna och kommunikationen med styrningen via I/O-kortet fungerar. Konceptet med att testa en pumpstyrningshårdvara mot en mjukvarusimulering är ett snabbt, enkelt och kostnadseffektivt tillvägagångssätt.
In this master thesis a test platform was created to be able to test, evaluate and compare different pump controllers in a dry environment. The platform consists of a simulated pump station to which optional pump controllers can be connected, i.e. a Hardware-In-The-Loop system. The largest benefits from such a platform are flexibility, rapid feedback along with the possibility to recreate the exact same conditions for different pump controllers. The test platform was implemented in LabVIEW on a PC that communicated with the pump control hardware through an I/O-card for analog and digital signals. The system is configured by setting parameters for pumps, sump, inflow, pipe system etc. The flows, energies and temperatures are simulated based on the input values and the control signals from the pump controller. The sump level and other signals needed by the controller are fed back from the simulation. There is also the possibility to affect the system by applying for example a pump failure or a clogging. Three different test runs with different pump controllers were performed. The test runs indicate that both the simulation models and the I/O-communication work. The concept of testing pump control hardware against a software simulation is a rapid, simple and cost efficient procedure.

The focus of software engineering has traditionally been oriented toward new software construction inspite of the fact that very substantial costs arise in the maintenance phase of the software lifecycle. A key element in the maintenance phase is "program understanding" because the individuals assigned this task are typically distinct from those on the development team. Tools to assist with program understanding have, nevertheless, received only modest attention in recent years. In this thesis the topic is explored within the context of the development of a particular program understanding tool called PUMP. PUMP (Program Understanding Tool for MODSIM Programs) is a tool developed to help understand simulation models written in the object-oriented simulation language called MODSIM programs. It has a simple graphical user interface (GUI) and may be used for both system exploration and for browsing purposes as part of a professional software development tool. It quickly displays and provides views of complex inheritance trees, making it an important tool for understanding object-oriented systems.