Journal articles: 'Pumping chamber'

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Chung, Tien Tung, Chih Kang Lu, and Yi Ting Tu. "Design, Manufacturing and Pump-down Curve Simulation of High Vacuum Systems." Applied Mechanics and Materials 220-223 (November 2012): 575–79. http://dx.doi.org/10.4028/www.scientific.net/amm.220-223.575.

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This paper presents a vacuum system design for extreme ultraviolet lithography (EUV) and studies the prediction of pump-down curves for vacuum chambers. Related basic theories include gas laws, conductance for several kinds of flow regimes, equivalent length for pipes, outgassing, diffusion, and permeation etc. The simulation program consists of a MFC module and a MATLAB module. The MFC module is used to input necessary parameters, including start and target pressure for pumping, volume and inner surface area of vacuum chambers, configuration of pumping lines, performance of vacuum pumps, and gas loads. The MATLAB module deals with the pump-down curve calculation based on related theories. The governing equation of the conservation of mass in a pumped vacuum chamber is derived from extended Temkin isotherm. The pump-down curve of vacuum chamber is predicted by four steps, including calculation of equivalent length for pipes, conductance of pipes, and effective pumping speed of pumps, and pump-down time. An empty vacuum chamber is used to test the developed program. The pump-down curve reaches 6.5E-8 torr with 42 hours pump-down time in experiment measurement, and the simulated curve reaches 5.79E-8 torr at the same time point. The developed program can predict pump-down curve with a good accuracy in the range from low vacuum pressure to high vacuum pressure.

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Danilatos, Gerasimos D. "Reverse Flow Pressure Limiting Aperture." Microscopy and Microanalysis 6, no. 1 (January 2000): 21–30. http://dx.doi.org/10.1017/s1431927600000052.

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The reverse flow pressure limiting aperture is a device that creates and sustains a substantial gas pressure difference between two chambers connected via an aperture. The aperture is surrounded by an annular orifice leading to a third chamber. The third chamber is maintained at a relatively high pressure that forces gas to flow through the annular aperture into the first of said two chambers. The ensuing gas flow develops into a supersonic annular gas jet, the core of which is coaxial with the central aperture. A pumping action is created at the core of the jet and any gas molecules leaking through the aperture from the second chamber are entrained and forced into the first chamber, thus creating a substantial pressure difference between the first and second chamber.

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Danilatos, Gerasimos D. "Reverse Flow Pressure Limiting Aperture." Microscopy and Microanalysis 6, no. 1 (January 2000): 21–30. http://dx.doi.org/10.1007/s100059910002.

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Abstract The reverse flow pressure limiting aperture is a device that creates and sustains a substantial gas pressure difference between two chambers connected via an aperture. The aperture is surrounded by an annular orifice leading to a third chamber. The third chamber is maintained at a relatively high pressure that forces gas to flow through the annular aperture into the first of said two chambers. The ensuing gas flow develops into a supersonic annular gas jet, the core of which is coaxial with the central aperture. A pumping action is created at the core of the jet and any gas molecules leaking through the aperture from the second chamber are entrained and forced into the first chamber, thus creating a substantial pressure difference between the first and second chamber.

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Wang, S. S., X. Y. Huang, and C. Yang. "Valveless micropump with acoustically featured pumping chamber." Microfluidics and Nanofluidics 8, no. 4 (November 21, 2009): 549–55. http://dx.doi.org/10.1007/s10404-009-0533-3.

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Marks, L. D., M. Kubozoe, M. Tomita, M. Ukiana, T. Furutsu, and T. Matsui. "Design and initial performance of a UHV-HREM." Proceedings, annual meeting, Electron Microscopy Society of America 46 (1988): 658–59. http://dx.doi.org/10.1017/s0424820100105357.

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We report here on the basic design and the initial performance of a fully bakeable UHV-HREM. The instrument, see Figure 1,is based upon a conventional H-9000 electron microscope with the natural differential pumping of the column separating the standard gun and photographic chambers from the UHV specimen chamber. The addition of small ion pumps at the condenser aperture, the selected area aperture and between the two projector lenses (see Figure 2) (which attain operational pressures of ∼2 X 10-8, ∼2 X 10-8 and ∼2 X 10-7 Torr respectively) assist this differential pumping. To achieve full UHV performance the specimen region is bakeable to 200°C using a combination of tape and band heaters and quartz-halogen lamps. Specimens for HREM analysis can be pretreated in the transfer chamber which is shown in Figure 3. The specimens, held in a detachable side entry cartridge, can be moved both back and forward and rotated by 360° to face ports onto which equipment for LEED, ion beam, X-ray, evaporation and dye laser treatment of surfaces will be mounted; the transfer chamber acts as a conventional multi-port surface science chamber.

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NAKAMURA, Yasuo, Katsuaki NAGATOMO, Kazuo SOMEYA, and Hisao KITAYAMA. "Vacuum pumping system of 13meter diameter space chamber." SHINKU 33, no. 9 (1990): 738–46. http://dx.doi.org/10.3131/jvsj.33.738.

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Lee, Young Kwan, Jin Hyoung Lee, Sung Kun Lee, Sang Hwan Lee, Youn Jea Kim, and Hun Mo Kim. "Nano Manufacturing Using Fountain Pen Nano-Lithography with Active Membrane Pumping." Key Engineering Materials 326-328 (December 2006): 425–28. http://dx.doi.org/10.4028/www.scientific.net/kem.326-328.425.

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In this paper, nano manufacturing using the FPN (Fountain Pen Nano-Lithography) with active membrane pumping is investigated. This FPN has integrated pumping chamber, micro channel, and high capacity reservoir for continuous ink feed. The most important aspect in this probe provided the control of fluid injection using active membrane pumping in chamber. The flow rates in channel by capillary force are theoretically analyzed with two different working fluids, DPD (diphenyldichlorosilane) and water, including the cantilever deflection and the control of mass flow rates by the deflection of membrane. The theoretical results are compared with numerical ones that calculated by commercial code, FLUENT.

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Kaufmann, R., H. Reul, and G. Rau. "Electromechanical Artificial Heart with a New Gear Type and Angled Pump Chambers." International Journal of Artificial Organs 15, no. 8 (August 1992): 481–87. http://dx.doi.org/10.1177/039139889201500807.

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The intrathoracic anatomical situation after explantation of the natural heart defines the maximum available space for the design of the housing as well as of the inlet-and outlet connectors of a fully implantable electromechanical artificial heart. Based on computer-assisted anatomical studies, a total artificial heart housing is designed which facilitates an oblique orientation of the pumping chambers for a better fluidmechanical and anatomical arrangement of the in- and outlet connectors. The pumping chamber geometry is based on modifications of an existing cardiac assist-system. Subsequently a mechanical gear which conforms to this anatomically adapted housing is developed.

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Yanto, Restu Andri, Anggi Putra Anugrah, Tutik Sriani, and Gunawan Setia Prihandana. "Portable Desalination Chamber Utilizing Water Permeable Polyethersulfone (PES) Membrane." Applied Mechanics and Materials 842 (June 2016): 457–60. http://dx.doi.org/10.4028/www.scientific.net/amm.842.457.

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This paper presents design and fabrication of portable desalination chamber utilizing water permeable polyethersulfone (PES) membrane. The chamber has four stages of desalination process. Each stage has a membrane clamped by filter plate to desalinate sea water and an outlet to qualify the desalinated water from each stage. The chamber works without electrical power, hence desalination process can be carried out in remote areas where electricity source is difficult to find. The water stream is used to test the pumping system of the chamber to pump the water from the water container. The test shows that the pumping system of the chamber is working properly in delivering water to each stage of the chamber without any leakage. The membrane used in each chamber is a modified PES membrane which has high water permeability. Water permeability of the membrane will guarantee that the salt water will permeate easily through the membrane porous during desalination process, hence results in producing fresh water at the final outlet.

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Brazhnik, O. I., and A. A. Rudenko. "Pilot test results of GP-200/11x500-m stage chamber pump." Mining Industry (Gornay Promishlennost), no. 6/2020 (December 29, 2020): 53–55. http://dx.doi.org/10.30686/1609-9192-2020-6-53-55.

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The article reviews and analyses issues that include optimisation of pumping equipment for efficient drainage of saline water in conditions of underground mines. It describes approaches to design improvement of pumping equipment and shows the economic effect of its implementation based on the results of pilot tests.

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Kawasaki, Masahiro, Masateru Nose, Ichiro Onishi, and Makoto Shiojiri. "Structural Investigation of AlN/SiOx Nanocomposite Hard Coatings Fabricated by Differential Pumping Cosputtering." Microscopy and Microanalysis 22, no. 3 (April 12, 2016): 673–78. http://dx.doi.org/10.1017/s1431927616000611.

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AbstractAlN/SiOx nanocomposite coatings fabricated by differential pumping cosputtering (DPCS) were investigated by analytical electron microscopy. The DPCS system consists of two halves of a Chamber, A and B, for radio frequency (RF) magnetron sputtering deposition of different materials, and a substrate holder that rotates through the chambers. Al and SiO2 were sputtered in gas environments with a flow mixture of N2 and Ar gases at RF power of 200 W in the Al Chamber A and a flow of Ar gas at RF powers of 49 W in the SiO2 Chamber B. The substrates of (001) Si wafers heated at 250°C were rotated for 1,080 min at 3 rpm and alternately deposited by AlN and SiO2. AlN columnar crystals grew at a rate of ~0.3 nm/revolution preferentially along the hexagonal [0001] axis. Amorphous silicon oxide (a-SiOx), deposited at a rate of ~0.2 nm/revolution, was coagulated preferentially along the boundaries between the AlN columns and also the interfaces between the subgrains within the AlN columns. The a-SiOx played an important role in the increase in mechanical hardness of the AlN/SiOx composite coating by disturbing deformation of AlN crystal lattices.

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Chen, Sheng-Jui. "System for measuring vacuum-pump performance using the standard throughput method." ACTA IMEKO 7, no. 1 (April 1, 2018): 65. http://dx.doi.org/10.21014/acta_imeko.v7i1.489.

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Ultimate pressure of a vacuum system is determined by two parameters, namely the total gas load of vacuum system and the pumping speed (volume flow rate) of vacuum pump. After the total gas load of a system is estimated, the required pumping speed can be set. In this study, we constructed a system for measuring the pumping speed of vacuum pump according to ISO 21360-1:2012, in which three methods are described, i.e. the throughput method, the orifice method and the pump-down method. The vacuum pump under test is designed to be used in low vacuum range for evacuating a chamber at high pumping speed. For this reason, the throughput method was selected as the main method. The system consists of pressure gauges, thermometers, a flow meter and a test chamber. The system was used to measure the pumping speed at the inlet of the vacuum pump at several pressure points. We present the system setup, uncertainty evaluation and vacuum-pump performance results of this work.

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13

Gilpin, C. J. "Biological applications of ESEM: Examination of fully hydrated samples." Proceedings, annual meeting, Electron Microscopy Society of America 54 (August 11, 1996): 844–45. http://dx.doi.org/10.1017/s0424820100166683.

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The environmental scanning electron microscope (ESEM) utilises a secondary electron detector capable of operating at pressures in the range of 1 ~ 20 Torr (130 ~ 2700 Pascals). By use of differential pumping apertures the electron gun and column can be maintained at "normal" vacuum levels of 10-5 Torr. A pressure of 10-2 Torr exists within the secondary electron detector separated from the specimen chamber by another differential pumping aperture. The specimen chamber pressure is produced by admitting a gas to the chamber under operator control. The gas can be any ionisable gas. Water vapour is a commonly used chamber gas. By controlling chamber gas pressure and sample temperature, by means of a Peltier effect stage, condensation and evaporation can be produced. The ability to maintain samples in a fully hydrated state in this way singles out the Electroscan ® ESEM as a unique instrument. ESEM presents an opportunity to examine biological samples with their natural water content present.

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Aráujo, A., Maria F. Patrício, and José L. Santos. "Optimal pumping in a single chamber microbial fuel cell." Renewable Energy and Power Quality Journal 1, no. 06 (March 2008): 389–92. http://dx.doi.org/10.24084/repqj06.305.

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15

Mamajanov, Makhmudjon, Bakhtiyor Uralov, Marina Li, Eshmatboy Qalqonov, Panji Nurmatov, and Abdulatif Gayur. "Irrigation pumping stations according to the hydraulic and operational indicators of pumping units." E3S Web of Conferences 264 (2021): 03074. http://dx.doi.org/10.1051/e3sconf/202126403074.

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The paper presents the conditions and the degree of reduction of water supply and pressure of pumping stations (PS) depending on the hydraulic resistance of the water-supply channels and structures of the PS and other various factors. And also, the results of studies of the hydraulic and operational modes of water-supplying machine channels and structures of irrigation pumping stations are presented. Analyzing the operating conditions of the pumping units, it was found that the reasons for the decrease in their operating parameters are the following: a) an increase in the hydraulic resistance of the suction line due to sediment deposition in the intake chamber, as well as due to siltation and clogging of the PS suction pipeline; b) an increase in hydraulic resistance due to the accumulation of air at elevated points of the pressure pipeline, in particular, on the crest of the siphon outlet of the PS; c) a decrease in the hydraulic efficiency of pumping units due to an increase in the surface roughness of the parts of the flow path, it due to the effect of solid abrasive particles entering through the suction line of the PS. Also, the work presents the results of complex laboratory and field studies to study the intensity of wear of the elements of the flow path of centrifugal and axial pumps. The alternating pulsating load leads to an increase in the force of interaction of the hydroabrasive flow with the surface of the chamber and increases its wear by 10%, and also reduces the productivity of the pumping unit to 9%.

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Naumov, Vladimir, and Nikolay Velikanov. "CHARACTERISTICS OF WATER RING COMPRESSOR MACHINES VACUUM FISH PUMPING UNITS." Fisheries 2021, no. 1 (February 15, 2021): 94–98. http://dx.doi.org/10.37663/0131-6184-2021-1-94-98.

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The operation of the Samson KS910 pump under various conditions is investigated. The values of empirical constants in mathematical dependencies for calculating pump characteristics were found using the least squares method based on published experimental data. The results of calculating the productivity and power consumption of the Samson KS910 in the vacuum pump mode depending on the pressure in the working chamber at different values of the rotor speed and pressure in the working chamber are presented.

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17

Watanabe, S., S. Kurokouchi, and M. Aono. "Pumping properties using an electrolytic polished stainless steel vacuum chamber." Journal of Vacuum Science & Technology A: Vacuum, Surfaces, and Films 16, no. 5 (September 1998): 3084–87. http://dx.doi.org/10.1116/1.581463.

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18

Neumann, Andreas. "STG-ET: DLR Electric Propulsion Test Facility." Journal of large-scale research facilities JLSRF 4 (November 5, 2018): 134. http://dx.doi.org/10.17815/jlsrf-3-156-1.

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Abstract: DLR operates the High Vacuum Plume Test Facility Göttingen – Electric Thrusters (STG-ET). This electric propulsion test facility has now accumulated several years of EP-thruster testing experience. Special features tailored to electric space propulsion testing like a large vacuum chamber mounted on a low vibration foundation, a beam dump target made of low sputtering material, and a performant pumping system characterize this facility. The vacuum chamber is 12.2m long and has a diameter of 5m. With respect to accurate thruster testing, the design focus is on accurate thrust measurement, plume diagnostics, and plume interaction with spacecraft components. Electric propulsion thrusters have to run for thousands of hours, and with this the facility is prepared for long-term experiments. This paper gives an overview of the facility, and shows some details of the vacuum chamber, pumping system, diagnostics, and experiences with these components.

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Takahashi, Jun-ichi, Yuichi Utsumi, Teruo Hosokawa, Jun Ushiki, and Toshiaki Tadano. "A beamline for photochemical processes at atmospheric pressure." Journal of Synchrotron Radiation 5, no. 3 (May 1, 1998): 548–50. http://dx.doi.org/10.1107/s0909049597017585.

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A beamline especially designed for atmospheric photochemical reactions has been constructed at the NTT synchrotron radiation facility. By inserting a buffer helium chamber with Be and Si3N4 partition windows between the beamline and the reaction chamber, studies can be performed without the differential pumping systems normally used in existing photochemistry beamlines. The reaction chamber is equipped with a gas supply system and analysis systems to investigate gas-phase and surface reactions. Purging using dry purified gases in combination with water-bubbling gives effective control of water concentration in the reaction chamber.

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Kim, Hanseup, Khalil Najafi, and Luis P. Bernal. "Helmholtz Resonance Based Micro Electrostatic Actuators for Compressible Gas Control: A Microjet Generator and a Gas Micro Pump." Journal of Microelectronics and Electronic Packaging 7, no. 1 (January 1, 2010): 1–9. http://dx.doi.org/10.4071/1551-4897-7.1.1.

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This paper reports Helmholtz-resonance based micro electrostatic actuators to control compressible gaseous fluids in the micro scale. Particularly, it discusses design, fabrication, and testing results of two electrostatic actuators: a micro jet generator and an integrated peristaltic multistage micro pump. These electrostatic actuators vibrate a micro membrane in a micro chamber at a high frequency (>10 kHz), and easily induce the resonant behavior of compressible gases in the chamber. Such resonant behavior, often called the Helmholtz resonance, can repeatedly create instantaneous pressure in equilibrium between the inside and outside of the chamber and cause gas to rapidly exit the chamber, forming a collimated jet. The developed micro jet generator consists of multiple acoustic chambers in parallel; produces directional gas momentum from each chamber by utilizing the Helmholtz resonance; and collectively entrains nearby gas molecules to form a gas stream. The fabricated micro jet generator has a footprint of 1.6 × 1.6 cm2 and contains 25 acoustic micro thrusters. It operates using a 140 V and 70 kHz sinusoidal signal and produces a thrust of 55.6 μN, a maximum air velocity of 1.2 m/s, and consumes power of 3.11 mW. The developed micro pump consists of multiple acoustic chambers in series and produces a high total pressure by accumulating pressures across the multiple chambers, while maintaining high flow rates utilizing the fluidic resonance of each pumping chamber. The fabricated 18-stage pump produces the maximum air flow rate of 4.0 sccm and maximum pressure differentials of 17.5 kPa with total power consumptions of only 57 mW. Its total package volume is 25.1 × 19.1 × 1 mm3. It is notable that these electrostatic actuators, with their actuation membranes, acoustic chambers, fluidic channels, and micro valves, are fabricated into a single silicon chip by developing low temperature wafer bonding techniques to protect the polymer structures inside.

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Urishev, Boborakhim, Sobir Eshev, Fakhriddin Nosirov, and Ulugbek Kuvatov. "A device for reducing the siltation of the front chamber of the pumping station in irrigation systems." E3S Web of Conferences 274 (2021): 03001. http://dx.doi.org/10.1051/e3sconf/202127403001.

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It has been determined that the reduction of siltation of the front chamber is necessary because the deposited sediments seriously violate the planned hydraulic structure of the flow when water is sucked up by pumps, as a result of which their efficiency decreases. The method of calculating the pipeline system of a new device designed to significantly reduce the siltation of the front chamber of irrigation pumping stations by artificially creating turbulence in the water flow in the bottom layer of the structure is presented. This calculation methodology is based on the use of the theory of flooded water jets, which makes it possible to determine the main characteristics of the jet. The latter allows calculating the design parameters of the pipeline system. The results of experimental studies are presented to compare the calculated data with the results of experiments, as well as to determine the effectiveness of the proposed device for a significant reduction in siltation of the front chamber of irrigation pumping stations.

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Fang, Dan, Fei Wang, Xiao Hua Wang, and Si Ning Liu. "Solar Pumped Nd:YAG Laser by the Fresnel Lens." Key Engineering Materials 552 (May 2013): 345–48. http://dx.doi.org/10.4028/www.scientific.net/kem.552.345.

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Shortly after the invention of the laser, researchers began to dream of converting sunlight into laser radiation directly. A direct conversion of concentrated solar light into a coherent laser beam improved the conversion efficiency because of the simple design of the structure, which is an innovation in the new field of solar energy utilization. We utilize the Fresnel lens of 1m2 to collect solar light, which is coupled into the conical chamber pumping Nd:YAG crystal, in 5mm-diameter 80mm-length rod. The pumping cavity is designed to combine end-pumping with side-pumping, in which the pumping light comes from many directions. It could compensate the drawbacks of single end-pumping or side-pumping. In the experiment, we obtain the maximum laser output power of 2.5 W, with a slope efficiency achieving 1.3%. By the Tracepro ray-tracing software, simulating the incoming energy distribution in the focus of the Fresnel lens, the concentration ratio of 104 is achieved.

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Batenin, V. M., V. T. Karpukhin, M. M. Malikov, A. S. Averyushkin, M. A. Kazaryan, N. A. Lyabin, and R. A. Zakharyan. "The induction pumping of Coaxial Lasers on Self-Terminating Transitions." Alternative Energy and Ecology (ISJAEE), no. 16-18 (September 11, 2018): 98–112. http://dx.doi.org/10.15518/isjaee.2018.16-18.098-112.

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The paper presents the results of the numerical simulations of pumping a copper vapour laser by a repetitively pulsed induction (electrodeless) discharge. We have investigated the version of the laser with an annular discharge volume formed by two coaxial cylinders. Such coaxial chamber is shown to be more appropriate for the induction pumping than the conventional cylindrical chamber. In the first case, higher coupling factors in the transformercoupled circuit of the induction discharge as well as rather high curl electric field are achieved. Moreover, from the ecological point of view, the coaxial chamber appears to be safer for the surrounding personnel in terms of their exposure to electromagnetic radiation. The present work briefly presents the physical model of the laser which describes the dynamics of the plasma parameters, the kinetics of the inverse population of the working levels for the laser on self terminating transitions as well as the development of the induction radiation. The paper also presents the electrical equations describing the simplest source of electrical pump pulses. The thermal characteristics of the working medium are estimated and the design calculations of the chamber are performed. The numerical experiments have found that, in contrast to the case of a conventional copper vapour laser with aperiodic discharge, in the regarded versions of the copper vapour laser the pump pulse is realized as a train of high-frequency damped oscillations. The analysis of the physical processes occurring in the plasma of the high-frequency discharge is carried out. The pulsed behaviour of the Joule heat power is shown to release results in pronounced pulsations of the electron temperature. This fact, however, does not significantly affect the operation of the laser on self-terminating transitions. In the optimal pumping regimes, subtle oscillations are merely observed for the inverse population of the copper atom working levels and for the intensity in the radiation pulse. High output laser characteristics achieved in the numerical simulations demonstrate the potential for efficient pumping of the copper vapour laser using the inductive method which is new for such lasers.

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Wang, Jiantao, Xiaolong Zhao, Xiafei Chen, and Haoren Yang. "A Piezoelectric Resonance Pump Based on a Flexible Support." Micromachines 10, no. 3 (February 28, 2019): 169. http://dx.doi.org/10.3390/mi10030169.

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Small volume changes are important factors that restrict the improvement of the performance of a piezoelectric diaphragm pump. In order to increase the volume change of the pump chamber, a square piezoelectric vibrator with a flexible support is proposed in this paper and used as the driving unit of the pump. The pump chamber diaphragm was separated from the driving unit, and the resonance principle was used to amplify the amplitude of the pump diaphragm. After analyzing the working principle of the piezoelectric resonance pump and establishing the motion differential equation of the vibration system, prototypes with different structural parameters were made and tested. The results show that the piezoelectric resonance pump resonated at 236 Hz when pumping air. When the peak-to-peak voltage of the driving power was 220 V, the amplitude of the diaphragm reached a maximum value of 0.43933 mm, and the volume change of the pump was correspondingly improved. When the pump chamber height was 0.25 mm, the output flow rate of pumping water reached a maximum value of 213.5 mL/min. When the chamber height was 0.15 mm, the output pressure reached a maximum value of 85.2 kPa.

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Zeng, Ping, Li’an Li, Jingshi Dong, Guangming Cheng, Junwu Kan, and Feng Xu. "Structure design and experimental study on single-bimorph double-acting check-valve piezoelectric pump." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 230, no. 14 (July 16, 2015): 2339–44. http://dx.doi.org/10.1177/0954406215596357.

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A novel piezoelectric pump called single-bimorph double-acting check-valve piezoelectric pump was proposed in this paper in order to improve the output performance of the single-bimorph single-chamber piezoelectric membrane pump. The constituent parts of the newly designed piezoelectric pump have no difference with the single-bimorph single-chamber check-valve piezoelectric membrane pump except the structural difference of the pump body. There are two serial-connection pump chambers which are formed by the two sides of the piezoelectric bimorph and the pump body of the newly designed piezoelectric pump. The new piezoelectric pump was fabricated, and output performance was experimentally investigated. The maximum flow rate against zero back pressure of the new pump was 318 ml/min and the pumping pressure reached 40.5 kPa at the operating voltage of 90 V. The output power was roughly twice that of the single-bimorph single-chamber check-valve piezoelectric membrane pump. The testing results proved that the new piezoelectric pump could enhance the output performance and the energy conversion efficiency of the piezoelectric bimorph comparing with the single-bimorph single-chamber check-valve piezoelectric membrane pump.

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Jiang, Hong, Ya Dong Qiu, and Mei Li. "Study on Loss Consumption for Closed Loop Air Suspension Height Control System with High & Low Pressure Chambers." Applied Mechanics and Materials 494-495 (February 2014): 1242–45. http://dx.doi.org/10.4028/www.scientific.net/amm.494-495.1242.

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Ride height adjustment of air suspension can be achieved by pumping air into or releasing air out of the air spring. However, energy loss would inevitably occur during the two processes,and test system of closed loop air suspension was established.Working process of the system was divided into three procedures as charging, discharging and boosting. Energy loss calculation method-compressed gas available energy was put forward, quantitative analysis of energy consumption during charging and discharging was carried out. Experiment results showed that energy consumption during charging process rises as initial air pressure of high pressure chamber increases, and during discharging and boosting processes, energy consumption decreases when initial air pressure of low pressure chamber increases. Under the same conditions, compared with open-loop air suspension, closed loop air suspension system with high & low pressure chambers can save plenty of energy.

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Zhang, Xin, Jian Wu Zhang, Li Rong Wan, and Meng Zang. "Research on Guarantee Equipment for Setting Load of Hydraulic Supports." Applied Mechanics and Materials 44-47 (December 2010): 2021–25. http://dx.doi.org/10.4028/www.scientific.net/amm.44-47.2021.

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To solve the shortage of setting load of hydraulic support, this paper puts forward a computer simulation method. The reason for the shortage of setting load is firstly analyzed by simulating the pressure curve of prop’s lower chamber and the displacement curve of movable prop. It can be found that even prop lower chamber is supplied with fluid continuously, the pressure won’t reach to the pressure of pumping station, and the setting load also can’t be achieved. Secondly, the principle of auto-pressurized guarantee equipment for setting load is present. Only acting on one displacement, the pressurized valve can reach the pressure of pumping station. Simulation result also indicates that it can meet the requirement of setting load in a short time after the top beam reaches to the roof.

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Gorbiychuk, M. I., O. T. Bila, N. T. Lazoriv, and A. M. Lazoriv. "METHOD OF ESTIMATING THE TECHNICAL STATE OF THE COMBUSTION CHAMBER OF A GAS TURBINE INSTALLATION ON THE BASIS OF ARTIFICIAL INTELLIGENCE." METHODS AND DEVICES OF QUALITY CONTROL, no. 2(43) (December 24, 2019): 68–77. http://dx.doi.org/10.31471/1993-9981-2019-2(43)-68-77.

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Reliable and efficient operation of the gas-pumping unit to a large extent depends on the technical state of the combustion chamber. The poor technical state of the combustion chamber reduces not only the efficiency of the gas pumping unit, but also increases the harmful emissions to the environment of harmful substances such as nitrogen and carbon oxides. Therefore, the determination of the technical state of the combustion chamber by the results of observations on the operation of the gas turbine installation is an actual scientific task. As a result of the analysis of literary sources and experimental studies, it is established that the mediated parameters characterizing the technical state of the combustion chamber are the total concentration of nitrogen oxides and the mean square value of the vibration velocity of the combustion chamber body. Over time, the elements of the combustion chamber are degrading, which leads to a change in the signs of the technical state of the combustion chamber. Indicators of a technical state form a plane of signs, which, with the help of the neural network Kohonen, are divided into three areas, each of which corresponds to a certain technical state of the combustion chamber - "good", "acceptable", "permissible". A method for constructing separate curves based on genetic algorithms is developed to distinguish the areas of technical states. The equation of separate curves is taken as a polynomial of a certain degree. The developed method on the basis of the class separation criterion determines not only the parameters of the equation of a separate curve but also the structure of such an equation by minimizing the class separation criterion. With the help of the developed software of the task of the technical condition assessment of the combustion chamber, the plane of the signs is divided into three classes and separate split curves are constructed.

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Yu, Weijian, and Ke Li. "Deformation Mechanism and Control Technology of Surrounding Rock in the Deep-Buried Large-Span Chamber." Geofluids 2020 (October 16, 2020): 1–22. http://dx.doi.org/10.1155/2020/8881319.

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The selection of the support scheme for deep-buried and large-span chambers has been a severe problem in underground engineering. To further study the mechanical mechanism of large deformation, based on the repair engineering of the chambers of Pingdingshan No.6 mine in China, the field investigation, laboratory test, numerical simulation, and theoretical analysis were studied. The surrounding rock of the central substation chamber (CSC) and the main pumping chamber (MPC) were classified according to the rock mass rating (RMR) classification method, and the main factors affecting the stability of the surrounding rock of the chambers were revealed. A prediction model of mechanical parameters of the surrounding rock was established based on the Hoek-Brown failure criterion. Additionally, the prediction results were used in FLAC3D to further analyze the failure of the original support scheme, and the feasibility of the restoration plan was proposed. Six key points of support technology for this kind of chamber were put forward. Comprehensive support and repair scheme, including “bolt, metal mesh, shotcrete, grouting, anchor cable, and combined anchor cable,” was put forward. The engineering practice indicated that the deformation rate was less than 0.7 mm/d, which was beneficial to the long-term stability of CSC and MPC. The implementation of this restoration project can provide a reference for other similar projects.

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30

Kim, Kyung-Yup, Cheoul-Hong Ahn, and Bum-Jun Kim. "Waterhammer for the In-Line Intake Pumping Station with Air Chamber." Journal of Fluid Machinery 15, no. 6 (December 1, 2012): 70–76. http://dx.doi.org/10.5293/kfma.2012.15.6.070.

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31

Shin, Soo Jai, Cheong Bong Chang, and Hyung Jin Sung. "Simulation of Valveless Pump Using Pumping Chamber Connected to Elastic Tube." Transactions of the Korean Society of Mechanical Engineers B 37, no. 2 (February 1, 2013): 111–17. http://dx.doi.org/10.3795/ksme-b.2013.37.2.111.

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32

Muhammadiev, M., B. Urishev, S. Juraev, and A. Boliev. "Detritus removal from a pumping-plant intake chamber with hydrajet pumps." IOP Conference Series: Materials Science and Engineering 883 (July 21, 2020): 012123. http://dx.doi.org/10.1088/1757-899x/883/1/012123.

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33

Gu, Yun-qing, Jie-gang Mou, Dong-shun Dai, Shui-hua Zheng, Deng-hao Wu, Lan-fang Jiang, Han-yu Shi, and Evan Wang. "Effect of pumping chamber on performance of non-overload centrifugal pump." Journal of Central South University 22, no. 8 (August 2015): 2989–97. http://dx.doi.org/10.1007/s11771-015-2835-9.

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34

Lee, Kwang Chul, and Nam Seo Goo. "Performance Evaluation of a Valveless Micropump Considering Electro-Structural-Fluid Interaction." Key Engineering Materials 345-346 (August 2007): 749–52. http://dx.doi.org/10.4028/www.scientific.net/kem.345-346.749.

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In this paper, the pumping performance of a piezoelectric micropump is simulated with commercial finite element analysis (FEA) software COMSOL Multiphysics 3.2a. The micropump is composed of a 4-layer piezo-composite actuator (LIPCA), a polydimethylsiloxane (PDMS) pump chamber, and two diffusers. The piezoelectric domain, structural domain and fluid domain are coupled in the simulation. Water flow rates are numerically predicted for geometric parameters of the micropump. Based on this study, the micropump is optimally designed to obtain its better pumping performance.

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35

Fangnon, Eric, Evgenii Malitckii, Yuriy Yagodzinskyy, and Pedro Vilaça. "Improved Accuracy of Thermal Desorption Spectroscopy by Specimen Cooling during Measurement of Hydrogen Concentration in a High-Strength Steel." Materials 13, no. 5 (March 10, 2020): 1252. http://dx.doi.org/10.3390/ma13051252.

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Thermal desorption spectroscopy (TDS) is a powerful method for the measurement of hydrogen concentration in metallic materials. However, hydrogen loss from metallic samples during the preparation of the measurement poses a challenge to the accuracy of the results, especially in materials with high diffusivity of hydrogen, like ferritic and ferritic-martensitic steels. In the present paper, the effect of specimen cooling during the experimental procedure, as a tentative to reduce the loss of hydrogen during air-lock vacuum pumping for one high-strength steel of 1400 MPa, is evaluated. The results show, at room temperature, the presence of a continuous outward hydrogen flux accompanied with the redistribution of hydrogen within the measured steel during its exposure to the air-lock vacuum chamber under continuous pumping. Cooling of the steel samples to 213 K during pumping in the air-lock vacuum chamber before TDS measurement results in an increase in the measured total hydrogen concentration at about 14%. A significant reduction in hydrogen loss and redistribution within the steel sample improves the accuracy of hydrogen concentration measurement and trapping analysis in ferritic and martensitic steels.

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36

Gao, Zheng Zhong, Qing Liang Zeng, and Shi Guang Li. "Intelligent Vacuum-Pumping Detection Device Base on STM32MCU." Applied Mechanics and Materials 190-191 (July 2012): 1002–5. http://dx.doi.org/10.4028/www.scientific.net/amm.190-191.1002.

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Large centrifugal water pumps are widely applied in various water-supply and drainage systems. The vacuum-pumping is pre-requisite for their start-up so that the intelligent vacuum-pumping detection device utilizing STM32F103 as the main controller was presented to realize the automatic control especially of unattended pumps. A differential pressure transducer was adopted to measure the vacuum degree in pump chamber. Afterwards, an electrical signal of corresponding value was output, and then entered the ADC of STM32F103 after conditioning. The threshold algorithm was introduced for the judgement whether vacuum-pumping had been accomplished. Actual applications indicated this detection device was feasible and reliable, and the judgement algorithm was simply implemented and performed well in practice.

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37

Aprilia, Lia, Ratno Nuryadi, Dwi Gustiono, Nurmahmudi, Arief Udhiarto, Djoko Hartanto, Brian Yuliarto, Makoto Hosoda, Yoichiro Neo, and Hidenori Mimura. "CO Gas-Induced Resonance Frequency Shift of ZnO-Functionalized Microcantilever in Humid Air." Journal of Nanomaterials 2017 (2017): 1–7. http://dx.doi.org/10.1155/2017/4824607.

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Resonance frequency shift of a zinc oxide- (ZnO-) functionalized microcantilever as a response to carbon monoxide (CO) gas has been investigated. Here, ZnO microrods were grown on the microcantilever surface by a hydrothermal method. The measurement of resonance frequency of the microcantilever vibrations due to the gas was carried out in two conditions, that is, gas flow with and without air pumping into an experiment chamber. The results show that the resonance frequency of the ZnO-functionalized microcantilever decreases because of CO in air pumping condition, while it increases when CO is introduced without air pumping. Such change in the resonance frequency is influenced by water vapor condition, and a possible model based on water-CO combination was proposed.

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38

Yang, K.-S., I.-Y. Chen, K.-H. Chien, and C.-C. Wang. "A numerical study of the nozzle/diffuser micropump." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 222, no. 3 (March 1, 2008): 525–33. http://dx.doi.org/10.1243/09544062jmes473.

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This study numerically investigates the performance of micronozzle/diffuser pump subject to the influence of frequency, opening angle, geometric dimension, and amplitude. For the effect of geometric dimension, the effect of chamber length is far more important than that of chamber depth because it can provide much more effective pumping volume. It is found that the net flowrate of a micropump increased with pumping frequency and opening angle. However, a level-off phenomenon of the net flowrate versus amplitude is seen at amplitudes nearby 150–200 μm and at an opening angle above 10°. This phenomenon is associated with two factors that compensate with each other. One is the free jet flow from the outlet that overturns and blocks the flow from the inlet. The other is the reduction of the strength of jet flow at a larger amplitude owing to effective increase of cross-sectional area.

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39

Аисса, Дуаиссиа Омар Хадж. "ЧИСЛЕННОЕ ИССЛЕДОВАНИЕ ТЕПЛООТДАЧИ В КАМЕРЕ ПОДШИПНИКА ГТД." Open Information and Computer Integrated Technologies, no. 81 (November 16, 2018): 92–103. http://dx.doi.org/10.32620/oikit.2018.81.10.

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To determine the required oil pumping through the GTE rotor support, an accurate calculation of the heat flow from the engine to the GTE bearing chamber is necessary. The complexity of the mathematical description of thermo-hydraulic processes is associated with the presence of a multiphase mixture in the bearing chamber, consisting of oil, going for lubrication and cooling of the support elements, and air, used for seals pressurization. The work is devoted to the issues of numerical study of the effect of regime parameters on the heat transfer coefficient in the bearing chamber of the GTE. For these purposes, the methodology based on conservation laws and CFD modeling methods is applied. The change in the heat transfer coefficient in the characteristic sections of the chamber is considered. The influence of the oil film distribution around the circumference of the chamber is shown.

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40

Demikhov, K. E., U. S. Gordeeva, and A. A. Ochkov. "Algorithm for Determining Optimum Runner Number in the Blading Section of a Turbomolecular Pump." Herald of the Bauman Moscow State Technical University. Series Mechanical Engineering, no. 1 (130) (February 2020): 119–27. http://dx.doi.org/10.18698/0236-3941-2020-1-119-127.

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The paper considers developing an algorithm for determining the optimum runner number in the blading section of a turbomolecular pump. Such pumps are built into chromatograph mass spectrometers for ensuring vacuum production in the chamber. Turbo-molecular pumps boast a number of advantages over other pumping solutions since it is possible to arrive at the required pumping parameters by means of selecting the optimum blading section configuration. In order to solve this problem, we present an algorithm for calculating the optimum runner number in the blading section of a turbomolecular pump, ensuring the pumping characteristics required: pumping speed and pressure ratio. The algorithm is based on well-known analytical expressions describing processes taking place in pumps of this type, which means it is highly computationally efficient. We determined the respective blading section parameter values, selected the values of empirical coefficients and plotted the pumping performance for the first two runners. The algorithm developed may be used to optimise mass and dimensions of turbomolecular pumps, which could significantly expand their use.

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41

Meng, J., X. T. Yang, J. H. Zhang, W. S. Yang, D. Z. Guo, Z. J. Hu, Y. G. Zhao, S. J. Hou, and C. Luo. "Research of TiZrV Pumping Coatings on the Inner Walls of Vacuum Chamber." Physics Procedia 32 (2012): 865–68. http://dx.doi.org/10.1016/j.phpro.2012.03.648.

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42

Lee, Sunmi, and Eunok Jung. "A two-chamber model of valveless pumping using the immersed boundary method." Applied Mathematics and Computation 206, no. 2 (December 2008): 876–84. http://dx.doi.org/10.1016/j.amc.2008.09.047.

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43

Feng, Yan, Meng Dong, Xue Min Sheng, Yong Jun Cheng, Lan Zhao, and Rui Fang Zhang. "Study on the Performance of Measurement Apparatus for Vacuum Material Outgassing Rates." Applied Mechanics and Materials 263-266 (December 2012): 452–56. http://dx.doi.org/10.4028/www.scientific.net/amm.263-266.452.

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A measurement apparatus for vacuum material outgassing rates was developed, which was mainly composed of four systems, including pumping system, switching between two pumping paths(SPP) measurement system, constant volume measurement system, bake heating and light irradiation heating system. The ultimate pressure, 10-9Pa, was thus obtained in the UHV chamber by combining the magnetically levitated turbo pump with mechanical pump. The test principles of constant volume method and SPP method were described, and several vacuum material outgassing rates such as copper were tested at room temperature. The lower measurement limiting value of apparatus can be extended to 10-12 Pam3s-1cm-2.

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44

Pilo-Restuccia, S., and L. Rojas-Solo´rzano. "A New Model to Simulate Gas Injection in Gas Chamber Pumps." Journal of Energy Resources Technology 126, no. 4 (December 1, 2004): 279–84. http://dx.doi.org/10.1115/1.1789518.

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Currently, there exist large heavy-oil reserves in countries like Venezuela and Canada. In Venezuela, heavy oil represents 69% of the reserves, and its exploitation is not always feasible using traditional pumping technologies. In particular, this is the case of some in-lake oil wells in Venezuela, which are impossible to exploit by means of any known efficient way of oil lifting. An alternative is the gas-chamber pumping (GCP), an intermittent artificial lift method used in diverse areas of USA, in shallow wells with heavy oil and in areas where a source of high-pressure gas exists. Few works are reported on the modeling of the phenomena associated to GCP, the most rigorous being the one published by PDVSA-Intevep in the year 2000. This model, however, omits some key aspects related with gas injection, which affects its precision to simulate or design GCP systems. The present work develops a model to rigorously simulate the stage of gas injection into the chamber, incorporating aspects like the flow of gas from the supply manifold up to the wellhead, the gas expansion within the injection valve, the descending flow along a coiled tubing, and the heat transfer associated. The pressurization process and chamber venting are also modeled. The model predictions are in excellent agreement with experimental data [1].

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45

Piragino, Antonio, Farbod Faraji, Maryam Reza, Eugenio Ferrato, Annalisa Piraino, and Tommaso Andreussi. "Background Pressure Effects on the Performance of a 20 kW Magnetically Shielded Hall Thruster Operating in Various Configurations." Aerospace 8, no. 3 (March 9, 2021): 69. http://dx.doi.org/10.3390/aerospace8030069.

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The paper reports the characterization results of a 20 kW-class magnetically shielded Hall thruster in three different configurations and operating with a centrally mounted cathode. The characterization was carried out at two different pumping speeds in SITAEL’s IV10 vacuum chamber, resulting in two different background pressure levels for each tested operating point. A linear behavior of discharge current and thrust values versus the anode mass flow rate was noticed for both pumping speeds levels and for all the three configurations. In addition, the thrust and discharge current values were always found to be lower at lower background pressure levels. From the performance levels, a preliminary estimate of the ingested mass flow rates was performed, and the values were then compared to a recently developed background flow model. The results suggested that, for this thruster and in the tested operating regimes, the change in performance due to background pressure could be ascribed not only to the ingestion of external mass flow coming from the chamber but also to other physical processes caused by the flux of residual background neutrals.

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Boutsikou, Maria, Wei Li, and Michael A. Gatzoulis. "Non-invasive management of obstructive sleep apnoea in a Fontan patient." Cardiology in the Young 29, no. 7 (June 17, 2019): 977–79. http://dx.doi.org/10.1017/s1047951118001695.

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AbstractIn patients with CHD after Fontan palliation, there is a lack of a pumping chamber in the pulmonary circulation; thus, pulmonary blood flow and cardiac output are sensitive to increased pulmonary vascular resistance; if obstructive sleep apnoea is present, there are legitimate concerns from continuous positive airway pressure ventilation, which may hinder pulmonary blood flow.

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47

Ervin, Matthew H. "A Simple Low-Vacuum Environmental Cell." Microscopy and Microanalysis 9, no. 1 (January 31, 2003): 18–28. http://dx.doi.org/10.1017/s1431927603030022.

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The environmental cell device discussed in this paper provides a modest low-vacuum scanning electron microscopy (SEM) capability to a standard SEM without requiring additional pumping. This environmental cell confines a volume of low vacuum in contact with the sample surface using a container that has an aperture for admitting the primary electron beam. The aperture is large enough to permit a limited field of view of the sample, and small enough to limit the outflow of gas into the SEM chamber to that which can be accommodated by the standard SEM pumping system. This environmental cell also functions as a gaseous detector device.

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48

Redington, Andrew N. "Functional assessment of the heart after corrective surgery for complete transposition." Cardiology in the Young 1, no. 1 (January 1991): 84–90. http://dx.doi.org/10.1017/s1047951100000135.

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SummaryThe justification for the introduction of the arterial switch procedure was based, primarily, on concern regarding the long-term ability of the right ventricle to perform as the systemic pumping chamber. In this article, the functional performance of both the systemic and pulmonary ventricles after atrial redirection procedures and the arterial switch operation will be discussed.

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49

Lee, T. S., and K. L. Ngoh. "Air Entrainment Effects on the Pressure Transients of Pumping Systems With Weir Discharge Chamber." Journal of Fluids Engineering 124, no. 4 (December 1, 2002): 1034–43. http://dx.doi.org/10.1115/1.1514204.

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This paper presents a new model for the study of air entrainment on the extreme pressure surges in pumping systems. For the present fluid system considered with a weir discharge chamber, numerical investigations showed that, with the proposed model of the air entrainment, reasonable predictions of transient pressures with proper phasing and attenuation of pressure peaks can be obtained. The results obtained are consistent with observations from field measurements made when the pumps were operating at low pump cutout levels where air entrainment due to attached surface vortex and falling jets from the inflow near the pump intake were present. Further studies were also made on the design characteristics of the weir discharge chamber on the extreme pressure transients for the unsteady flow in the pipeline system with various degrees of air entrainment.

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50

Tarbell, J. M., J. P. Gunshinan, D. B. Geselowitz, G. Rosenberg, K. K. Shung, and W. S. Pierce. "Pulsed Ultrasonic Doppler Velocity Measurements Inside a Left Ventricular Assist Device." Journal of Biomechanical Engineering 108, no. 3 (August 1, 1986): 232–38. http://dx.doi.org/10.1115/1.3138608.

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In this study we have employed a single channel, pulsed ultrasonic Doppler velocimeter to measure instantaneous velocity distributions within the pumping chamber of a ventricular assist device. Instantaneous velocities have been decomposed into periodic mean and turbulent fluctuating components from which estimates of Reynolds stresses within the chamber and mean shear stresses along the wall of the chamber have been obtained. A review of the complete data set indicates a maximum value of the mean wall shear stress of 25 dynes/cm2 and a maximum Reynolds stress of 212 dynes/cm2. These values are lower than those measured distal to aortic valve prostheses in vitro and are well below levels known to damage blood components. Core flow patterns, wall washing patterns and flow stagnation points are also revealed.

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Journal articles on the topic 'Pumping chamber'

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