Dynamic behavior and difference pressure control of difference pressure regulator for dry gas seals

2022 ◽  
Vol 165 ◽  
pp. 108350
Author(s):  
Andriy V. Zahorulko ◽  
Yong-Bok Lee
Keyword(s):  
Dynamic Behavior ◽  
Pressure Control ◽  
Pressure Regulator ◽  
Gas Seals

Study on the Characteristics of a New Type Pneumatic Pressure Regulator

2013 ◽  
Vol 347-350 ◽  
pp. 157-161
Author(s):  
Jun Gong Ma ◽  
Xin Hua Chen
Keyword(s):  
Mechanical Valve ◽  
Pressure Control ◽  
Superior Performance ◽  
Mechanical Pressure ◽  
Pressure Regulator ◽  
Valve Body ◽  
Pneumatic Pressure ◽  
Output Pressure ◽  
Flow Disturbances ◽  
Downstream Flow

ressure regulators are very important elements in pneumatic systems. Purely mechanical pressure regulators are commonly used to control the supply pressure to the desired value. The intelligent pneumatic pressure regulator (IPPR) is designed as the demands of pressure control precision increase. Its prominent advantage is the ability to achieve accurate output pressure, remote control and centralized management. In this paper, the IPPR consists of a mechanical valve body, a stepping motor, a microcontroller, a pressure sensor. Herein, its pneumatic characteristics were analyzed, and the pressure control algorithm was presented. The superior performance of IPPR was shown in AMEsim simulation, especially in terms of avoiding affects from upstream pressure and downstream flow disturbances.

scholarly journals Thermally controlled microfluidic back pressure regulator

2022 ◽  
Vol 12 (1) ◽  
Author(s):  
Karolina Svensson ◽  
Simon Södergren ◽  
Klas Hjort
Keyword(s):  
Large Scale ◽  
Pressure Control ◽  
Back Pressure ◽  
Dead Volume ◽  
Pressure Regulator ◽  
Total Analysis System ◽  
Elevated Pressures ◽  
Upstream Pressure ◽  
Analysis System ◽  
Pressure Changes

AbstractBy using the temperature dependence of viscosity, we introduce a novel type of microfluidic lab-on-a-chip back pressure regulator (BPR) that can be integrated into a micro-total-analysis-system. A BPR is an important component used to gain pressure control and maintain elevated pressures in e.g. chemical extractions, synthesis, and analyses. Such applications have been limited in microfluidics, since the back pressure regularly has been attained by passive restrictors or external large-scale BPRs. Herein, an active microfluidic BPR is presented, consisting of a glass chip with integrated thin-film heaters and thermal sensors. It has no moving parts but a fluid restrictor where the flow resistance is controlled by the change of viscosity with temperature. Performance was evaluated by regulating the upstream pressure of methanol or water using a PID controller. The developed BPR has the smallest reported dead volume of 3 nL and the thermal actuation has time constants of a few seconds. The pressure regulation were reproducible with a precision in the millibar range, limited by the pressure sensor. The time constant of the pressure changes was evaluated and its dependence of the total upstream volume and the compressibility of the liquids is introduced.

Cryogenic Temperature Stabilization of the Daikin 308 Cryocooler

2011 ◽  
Author(s):  
Michael J. Smith ◽  
Jeff Jennings
Keyword(s):  
Cryogenic Temperature ◽  
Pressure Control ◽  
Observation Time ◽  
Helium Pressure ◽  
Pressure Regulator ◽  
Temperature Variations ◽  
Heterodyne Receiver ◽  
Time Period ◽  
Pressure Control System ◽  
Pressure Stability

We report on a scheme developed at the Harvard-Smithsonian Center for Astrophysics to stabilize longer term cryogenic temperature variations in equipment used for high frequency radio telescope receivers. Cryogenic temperature variations of the 30 minute time scale are reduced an average of 55 percent by controlling the helium pressure flowing through the cryostat. Applications in the field of cryogenic radio astronomy will benefit from this resulting reduction of power fluctuations and corresponding reductions in observation time on source. An Equilibar® back pressure regulator was used to allow helium from the compressor to bypass the cryostat, thereby providing a very stable pressure control system. Manually set reference port pressure regulates the helium bypass and deviates less than 6.2 × 10^−4 MPa for the 30 minute time period while power output deviations of the heterodyne receiver are reduced as a result of the increase in pressure stability an average of 46%.

scholarly journals An Electronically Controlled Pressure Regulator

1989 ◽  
Vol 111 (1) ◽  
pp. 75-82 ◽  
Author(s):  
D. L. Trumper ◽  
J. H. Lang
Keyword(s):  
Control Valve ◽  
Nonlinear Problems ◽  
Pressure Control ◽  
Operating Regime ◽  
Pressure Regulator ◽  
Control Scheme ◽  
Pressure Control System ◽  
Analysis Design ◽  
Electronic Compensation ◽  
Classical Control

This paper describes the analysis, design, implementation, and evaluation of an electronically controlled fluid back-pressure regulator system. The control scheme is unique in that it is purely electronic, and employs a nested pair of feedback loops. This approach overcomes several problems associated with purely mechanical regulation, such as friction in the control valve. Further, since the control is electronic, compensation functions are easily implemented via operational amplifier circuits. The pressure control system is derived with classical control techniques through linearization of the measured valve characteristics. The solutions to nonlinear problems encountered in the implementation are discussed. The design achieves good performance and stability over the entire pressure and flow operating regime.

scholarly journals Dry Gas Seal Developments and Contamination Prevention

1996 ◽  
Author(s):  
Stan O. Uptigrove ◽  
Paul S. Eakins ◽  
John E. Sears
Keyword(s):  
Dynamic Behavior ◽  
Preventive Measures ◽  
Operating Experience ◽  
Advanced Materials ◽  
Dry Gas Seal ◽  
Industry Standard ◽  
Gas Compression ◽  
Gas Seals ◽  
Materials Used ◽  
Rotor Dynamic

Dry gas seals have become the pipeline industry standard for sealing of centrifugal gas compression equipment. Recent applications have pushed the limits of materials used in their construction from exposure to ever increasing levels of pressure, speed and temperature. This provides the focus for a discussion of recent advances with the use of advanced materials, higher pressure, speed and temperature applications and bidirectional designs. Operating experience has been very favourable, enough to make dry gas seals a preferred standard, but the failures that have occurred raise two fundamental questions. The first concerns the resistance of gas seals to contamination and the second is their influence upon rotor dynamic behavior. Both of these predominant issues are reviewed along with advancements and preventive measures now available to address these concerns.

The Prediction of Startup Test With Load Rejection and Parametric Study of SBPCS for Lungmen Nuclear Power Plant

2010 ◽  
Author(s):  
Chiung-Wen Tsai ◽  
Chunkuan Shih ◽  
Hao-Tzu Lin ◽  
Jong-Rong Wang ◽  
Yng-Ruey Yuan ◽  
...  
Keyword(s):  
Time Constant ◽  
Parametric Analysis ◽  
Nuclear Power ◽  
Test Procedure ◽  
Pressure Rise ◽  
Pressure Control ◽  
Lag Time ◽  
Maximum Pressure ◽  
Pressure Regulator ◽  
Time Constants

A Lungmen RETRAN-3D model has been constructed to predict the transient behaviors for startup test, furthermore verify the acceptance criteria specified in the documents of startup test procedure. This study focuses on the prediction of the startup test with Load Rejection (LR) with bypass and the parametric analysis of lead-lag time constants in pressure regulator. For the analysis of LR with bypass, the major mitigation functions, i.e., Selected Control Rods Run-In (SCRRI) and turbine bypass function, are simulated to examine whether scram is initiated during the transient or not. The analytic results show the reactor is brought to a steady state without scram. The neutron flux in the final state is around 34%, and the pressure regulator sensed maximum pressure rise is limited to a maximum of 3kPa. The result also shows that the 110% steam bypass capacity is capable to mitigate the power increase caused by the positive reactivity insertion as a result of pressure-wave-induced void collapse. For the parametric analysis of lead-lag time constants in pressure regulator, the time domain response of Steam Bypass and Pressure Control System (SBPCS) is demonstrated by a step change of pressure setpoint and different combinations of lead-lag time constants defined in pressure regulator. The results show that the responses, i.e., response time and overshooting, are minimized when the lag time constant is between 4 to 6 seconds and the lead time constant is 50% to 70% of lag time constant. The analysis result of SBPCS provides the trend as a reference for the adjustment of lead-lag time constants during the future Lungmen startup test.

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