The Design and Theoretical and Experimental Study of the Plastic Hydraulic Valves

2016 ◽  
Author(s):  
Lubomir Marciniak ◽  
Michał Banaś ◽  
Jarosław Stryczek
Keyword(s):  
Flow Analysis ◽  
Major Elements ◽  
Fluid Power ◽  
Pressure Relief Valve ◽  
Future Research ◽  
Relief Valve ◽  
Pressure Relief ◽  
University Of Technology ◽  
System 1 ◽  
Hydraulic Valves

The overall popularity of plastics has not reached the industrial hydraulics yet. They are already widely used as a material for seals and minor parts, such as handles, covers, caps, etc., but still the dominant material for the making of the key elements is steel. The main project carried out by the Fluid Power Research Group of Wroclaw University of Technology is a fluid power system with the major elements made of plastics. The primary goal is to make a set of prototype plastic elements that within a low pressure range will perform comparably well to the elements which are traditionally made of steel and are available on the market. That set includes two basic hydraulic valves: the pressure relief valve and the on/off valve. The authors present the research that has been done on them so far, as well as evaluate the possible advantages and problems associated with the application of plastics for the making of the system.1 The analysis of the traditional, metal valves’ designs was done as the theoretical base for the plastic valves’ design. All the main parts were studied, especially the main operating elements (poppet and its seat or a piston). In the paper, the references have been provided where possible. All the analyzed features are discussed in terms of using plastics as the main material. In the summary, it is pointed out which of them could easily be transferred, which need to be tested and which are clearly non-transferable and need to be redesigned. Based on guidelines resulting from the analysis of the traditional metal valves, the first plastic prototypes of the pressure relief valve and the on/off valve were designed, constructed and tested by the FPRG. Details of the design are discussed, focusing on its versatility achieved by the usage of interchangeable parts. The early design problems are also shown, as well as the way how they were dealt with. The steady state characteristics are presented and compared to industrial metal valves of the similar size available on the market. A part of the improvement process was an analysis of the flow inside the valve conducted by means of Computational Fluid Dynamics (CFD). The results and conclusions of the flow analysis are presented. The main differences between the plastics and steel are the mechanical properties, especially the lower rigidity. Much larger deformations of the loaded elements can possibly cause problems. Using the CFD results as loads, a structural analysis by means of the Finite Element Method was also carried out. The results and the discussion on whether the deformations are substantial or not and what kind of problems they may cause are presented in the paper. In the summary, the authors draw conclusions from the conducted design process and tests on the first generation prototypes, as well as discuss the reachability of the research objectives defined at its beginning, which regarded the plastic valves. The design of the second generation prototypes is also briefly discussed and the future research plans outlined.

Orifice Design of a Pilot-Operated Pressure Relief Valve

2016 ◽  
Vol 139 (3) ◽  
Author(s):  
Sang Chan Jang ◽  
Jung Ho Kang
Keyword(s):  
Flow Analysis ◽  
Strong Shock ◽  
Pressure Relief Valve ◽  
Orifice Diameter ◽  
Relief Valve ◽  
Pressure Relief ◽  
Production Processes ◽  
Design Variables ◽  
The Impact ◽  
Design And Production

An important safety factor to be considered when designing a plant is the prevention of overpressure-induced explosions, to which many plants are vulnerable because of pressurized fluids in plant components. A pilot-operated pressure relief valve is a core device for venting off overpressure formed inside vessels and pipelines. The pilot-operated pressure relief valve has a highly complicated structure, and its design and production should be thoroughly studied. In this study, a simplified structure for the pilot-operated pressure relief valve was proposed to facilitate the design and production processes, and the effective ranges of its design variables were determined to enable the prediction of the impact of the design variables in the design and production processes. The ranges determined were validated by a numerical flow analysis and experiment as follows. We calculated the maximum orifice diameter at which the main valve does not open and examined the minimum orifice diameter that can resist the impact of strong shock waves. Additionally, we defined the orifice diameter range that ensures the stable opening and closing of the main valve under various pressure conditions. The effective ranges of the design variables determined in this study can be used to ensure safe operation of a pilot-operated pressure relief valve under various pressure conditions with the design of the proposed simplified structure.

Bond Graph Modeling of a Two-Stage Pressure Relief Valve

2013 ◽  
Vol 135 (4) ◽  
Author(s):  
Osama Gad
Keyword(s):  
Mathematical Model ◽  
Graph Model ◽  
Bond Graph ◽  
Fluid Power ◽  
Pressure Relief Valve ◽  
System Component ◽  
Bond Graphs ◽  
Relief Valve ◽  
Two Stage ◽  
Pressure Relief

This study examined the use of bond graphs for the modeling and simulation of a fluid power system component. A new method is presented for creating the bond graph model, based upon a previously developed mathematical model. A nonlinear dynamic bond graph model for a two-stage pressure relief valve has been developed in this paper. Bond graph submodels were constructed considering each element of the studied valve assembly. The overall bond graph model of the valve was developed by combining these submodels using junction structures. Causality was then assigned in order to obtain a computational model, which could be simulated. The simulation results of the causal bond graph model were compared with those of a mathematical model, which had been also developed in this paper based on the same assumptions. The results were found to correlate very well both in the shape of the curves, magnitude, and response times. The causal bond graph model was verified experimentally in the dynamic mode of operation. As a result of comparison, bond graphs can quickly and accurately model the dynamics in a fluid power control system component. During the simulation study, it was found that nonlinearity occur due to three factors: changes in pressure, which cause nonlinear velocity changes of the flow rate; changes in the throttling area of the valve restriction, which usually changes nonlinearly; and changes in the discharge coefficient of the throttling area of the valve restriction, which does not remain constant.

Identification of Fluid Power Component Behaviour Using Dynamic Flowrate Measurement

1995 ◽  
Vol 209 (3) ◽  
pp. 179-191 ◽  
Author(s):  
J Watton ◽  
Y Xue
Keyword(s):  
Experimental Approach ◽  
Fluid Power ◽  
Pressure Relief Valve ◽  
Relief Valve ◽  
Nitrogen Gas ◽  
Pressure Relief ◽  
Dynamic Impedance ◽  
State Pressure ◽  
Power Component ◽  
Impedance Magnitude

An identification concept is developed utilizing direct measurement of the transient flowrate and pressure to determine the dynamic characteristics of fluid power components. The fundamental experimental approach is discussed and applied to a range of sizes of a bladder-type accumulator and also to a single-stage pressure relief valve. The gas charging characteristic of the accumulator was determined for three different sizes and during dynamic operation. It is shown how the nitrogen gas index of compression varies during operation and a relationship between the index and instantaneous flowrate is proposed. Measurements obtained with the pressure relief valve were used to identify its dynamic impedance in the frequency domain via time series analysis and transformation. The predictions are compared with a linearized mathematical model showing good correlation over a wide frequency band. A particular feature was found to be the use of the impedance magnitude-frequency asymptotes for validation of the steady state pressure-flowrate characteristic.

Optimization of Operation Parameters for Direct Spring Loaded Pressure Relief Valve in a Pipeline System

2018 ◽  
Vol 140 (5) ◽  
Author(s):  
Hyunjun Kim ◽  
Sanghyun Kim ◽  
Youngman Kim ◽  
Jonghwan Kim
Keyword(s):  
Pressure Relief Valve ◽  
Pipeline System ◽  
Relief Valve ◽  
Pressure Relief ◽  
Computational Costs ◽  
Constant Degree ◽  
System A ◽  
Disk Mass ◽  
Analysis Scheme ◽  
Surge Control

A direct spring loaded pressure relief valve (DSLPRV) is an efficient hydraulic structure used to control a potential water hammer in pipeline systems. The optimization of a DSLPRV was explored to consider the instability issue of a valve disk and the surge control for a pipeline system. A surge analysis scheme, named the method of characteristics, was implemented into a multiple-objective genetic algorithm to determine the adjustable factors in the operation of the DSLPRV. The forward transient analysis and multi-objective optimization of adjustable factors, such as the spring constant, degree of precompression, and disk mass, showed substantial relaxation in the surge pressure and oscillation of valve disk in a hypothetical pipeline system. The results of the regression analysis of surge were compared with the optimization results to demonstrate the potential of the developed method to substantially reduce computational costs.

The Effect of Pressure Relief Valve Blowdown and Fire Conditions on the Thermo-Hydraulics Within a Pressure Vessel

2006 ◽  
Vol 128 (3) ◽  
pp. 467-475 ◽  
Author(s):  
A. M. Birk ◽  
J. D. J. VanderSteen
Keyword(s):  
Thermal Stratification ◽  
Pressure Vessels ◽  
Pressure Relief Valve ◽  
Relief Valve ◽  
Pressure Relief ◽  
Pressure Transducers ◽  
Hydrocarbon Pool ◽  
Computer Controlled ◽  
C 50 ◽  
Fire Conditions

In the summers of 2000 and 2001, a series of controlled fire tests were conducted on horizontal 1890liter (500 US gallon) propane pressure vessels. The test vessels were instrumented with pressure transducers, liquid space, vapor space, and wall thermocouples, and an instrumented flow nozzle in place of a pressure relief valve (PRV). A computer controlled PRV was used to control pressure. The vessels were heated using high momentum, liquid propane utility torches. Open pool fires were not used for the testing because they are strongly affected by wind. These wind effects make it almost impossible to have repeatable test conditions. The fire conditions used were calibrated to give heat inputs similar to a luminous hydrocarbon pool fire with an effective blackbody temperature in the range of 850°C±50°C. PRV blowdown (i.e., blowdown=poppressure−reclosepressure) and fire conditions were varied in this test series while all other input parameters were held constant. The fire conditions were varied by changing the number of burners applied to the vessel wall areas wetted by liquid and vapor. It was found that the vessel content’s response and energy storage varied according to the fire conditions and the PRV operation. The location and quantity of the burners affected the thermal stratification within the liquid, and the liquid swelling (due to vapor generation in the liquid) at the liquid∕vapor interface. The blowdown of the PRV affected the average vessel pressure, average liquid temperature, and time to temperature destratification in the liquid. Large blowdown also delayed thermal rupture.

scholarly journals Forensic Engineering Techniques For Testing And Predicting Lp-Gas Container Relief Venting

2004 ◽  
Vol 21 (2) ◽  
Author(s):  
James A. Petersen
Keyword(s):  
Test Data ◽  
Pressure Relief Valve ◽  
Relief Valve ◽  
Pressure Relief ◽  
Temperature Changes ◽  
Flammable Gas ◽  
Forensic Engineering ◽  
Pressure Changes ◽  
Liquefied Gas

When An Lp-Gas Container Is Involved In A Fire, Flammable Gas Is Usually Vented From The Relief Valve. One Of The First Questions Is Whether The Container Vented The Gas That Caused The Fire Or Whether Gas Was Vented Due To The Fire Heating The Container. If The Relief Valve Vents Gas That Initiates The Fire, It Is Usually Due To An Overfilled Container. This Paper Discusses; 1) The Prediction Of The Rate Of Container Warming Due To Normal Temperature Changes, 2) The Resulting Pressure Changes Of The Liquefied Gas, 3) The Reaction Of The Pressure Relief Valve And The Quantity Of Lp-Gas Vented During The Operation Of The Relief Valve, 4) Designing The Experiment And 4) Adjusting The Model To Reflect Test Data.

The static and dynamic characteristics of a pressure relief valve with a proportional solenoid-controlled pilot stage

2002 ◽  
Vol 216 (2) ◽  
pp. 143-156 ◽  
Author(s):  
R Maiti ◽  
R Saha ◽  
J Watton
Keyword(s):  
Mathematical Model ◽  
Dynamic Characteristics ◽  
Dynamic Behaviour ◽  
Practical Experience ◽  
Pressure Relief Valve ◽  
Relief Valve ◽  
Pressure Relief ◽  
Static And Dynamic Characteristics ◽  
Good Comparison ◽  
The Mathematical Model

The steady state and dynamic characteristics of a two-stage pressure relief valve with proportional solenoid control of the pilot stage is studied theoretically as well as experimentally. The mathematical model is studied within the MATLAB-SIMULINK environment and the non-linearities have been considered via the use of appropriate SIMULINK blocks. The detailed modelling has resulted in a good comparison between simulation and measurement, albeit assumptions had to be made regarding the solenoid dynamic characteristic based upon practical experience. The use of this characteristic combined with additional dynamic terms not previously considered allows new estimations of internal characteristics to be made such as the damping flowrate. The overall dynamic behaviour has been shown to be dominated by the solenoid characteristic relating force to applied voltage.

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