Steady-State Positions of a Pop Action Safety Valve

2011 ◽  
Author(s):  
Jean-Franc¸ois Rit ◽  
Pierre Moussou ◽  
Christophe Teygeman
Keyword(s):  
Steady State ◽  
Pressure Drop ◽  
Relief Valve ◽  
Pressure Relief ◽  
Working Pressure ◽  
Process Industries ◽  
Water Pipes ◽  
Upstream Pressure ◽  
Pressure Relief Valves ◽  
The Stability

Pressure relief valves in water pipes are known to sometimes chatter when the inlet pressure slightly exceeds the maximum allowable working pressure (MAWP) value. Though these devices are responsible for numerous fatigue issues in process industries, there is a relatively low number of technical publications describing well-established facts about them, especially for heavy fluids. The present study deals with the investigation of the stability of a pressure relief valve when a pressure drop device is arranged upstream. The valve is a simple spring device, with a 1″1/2 inlet diameter and a set pressure equal to 3 MPa. The 12% to 66% range of relative opening for this valve exhibit an unstable static equilibrium of the plug, designed to achieve the so called “pop action”; as soon as the pressure set point is reached, a runaway process leads to the full opening. The statically stable regimes were observed in former studies with respect to the upstream pressure and to the plug position, with a test rig arrangement which ensured an almost constant pressure upstream. In the present study, high pressure drop devices are arranged upstream, in order to stabilize the hydraulic regimes. It is found that the upstream pressure drop devices significantly enlarge the range of steady state plug positions and upstream pressures. Pressure and plug position measurements are shown with a time resolution lower than 2 ms. Comparison with hydraulic regimes of the former studies indicate that the presence of an upstream pressure drop modifies the plug balance. It is proposed that the arrangement of pressure drop device upstream may significantly reduce the risk of valve instability in water pipes.

Instability of Pressure Relief Valves in Water Pipes

2010 ◽  
Vol 132 (4) ◽  
Author(s):  
P. Moussou ◽  
R. J. Gibert ◽  
G. Brasseur ◽  
Ch. Teygeman ◽  
J. Ferrari ◽  
...  
Keyword(s):  
Pressure Drop ◽  
Negative Pressure ◽  
Dynamic Instability ◽  
Pressure Sensors ◽  
Displacement Sensor ◽  
Relief Valve ◽  
Pressure Relief ◽  
Water Pipes ◽  
Spring Force ◽  
Pressure Relief Valves

Pressure relief valves in water pipes are known to sometimes chatter when the inlet pressure slightly exceeds the set pressure. While these devices are responsible for numerous fatigue issues in process industries, there is a relatively low number of technical publications covering their performance, especially in heavy fluid applications. The present study is intended as a contribution to the understanding of pressure relief valve dynamics, taking into account fluid-structure interactions. A series of tests were performed with a water relief valve in a test rig. Adjusting the set pressure of the valve to about 30 bars, an upstream pressure varying from 20 bars to 35 bars was imposed, so that the valve opened and the water flow varied from a few m3/h to about 80 m3/h. During the tests, the pipe was equipped upstream and downstream of the valve with static pressure sensors and a flowmeter, the disk lift was measured with a laser displacement sensor, and the spring force was recorded simultaneously. Several fluctuating pressure sensors were also installed in the inlet pipe. Static instability is investigated by comparing the spring force to the hydraulic force. Dynamic instability is observed and it is shown that the resonant behavior of the disk generates an apparent negative pressure drop coefficient at some frequencies. This negative pressure drop coefficient can trigger a dynamic instability in a manner similar to the negative damping effect in leakage-flow vibrations.

Instability of Pressure Relief Valves in Water Pipes

2009 ◽  
Author(s):  
Pierre Moussou ◽  
Rene´ Jean Gibert ◽  
Gilles Brasseur ◽  
Christophe Teygeman ◽  
Je´roˆme Ferrari ◽  
...  
Keyword(s):  
Pressure Drop ◽  
Negative Pressure ◽  
Dynamic Instability ◽  
Pressure Sensors ◽  
Displacement Sensor ◽  
Relief Valve ◽  
Pressure Relief ◽  
Water Pipes ◽  
Spring Force ◽  
Pressure Relief Valves

Pressure relief valves in water pipes are known to sometimes chatter when the inlet pressure slightly exceeds the maximum allowable working pressure (MAWP) value. Though these devices are responsible for numerous fatigue issues in process industries, there is a relatively low number of technical publications describing well-established facts about them, especially for heavy fluids. The present study is intended as a contribution to the understanding of pressure relief valve dynamics, taking into account fluid-structure interactions. A series of tests was performed with a water relief valve upon a test rig. Adjusting the MAWP of the valve to about 30 bars, an upstream pressure varying from 20 to 35 bars was imposed, so that the valve opened and the water flow varied from a few m3/h to about 80 m3/h. During the tests, the pipe was equipped upstream and downstream of the valve with static pressure sensors and a flowmeter, the disc lift was measured with a laser displacement sensor, and the spring force was recorded simultaneously. Several fluctuating pressure sensors were also arranged in the inlet pipe. Static instability is investigated by comparing the spring force to the hydraulic force. Dynamic instability is observed and it is shown that the resonant behavior of the disc generates an apparent negative pressure drop coefficient at some frequencies. This negative pressure drop coefficient can trigger a dynamic instability in a manner similar to the negative damping effect in leakage-flow vibrations.

Dynamic Behavior of Transportation Pressure Relief Valves Under Simulated Fire Impingement Conditions

1999 ◽  
Vol 122 (1) ◽  
pp. 60-65 ◽  
Author(s):  
A. J. Pierorazio ◽  
A. M. Birk
Keyword(s):  
Dynamic Testing ◽  
Test Facility ◽  
Time Varying ◽  
Relief Valve ◽  
Pressure Relief ◽  
Flow Rates ◽  
Depth Analysis ◽  
Pressure Relief Valves ◽  
Accident Conditions ◽  
Insight Into

This paper presents the results of the first full test series of commercial pressure relief valves using the newly constructed Queen’s University/Transport Canada dynamic valve test facility (VTF) in Maitland, Ontario. This facility is unique among those reported in the literature in its ability to cycle the valves repeatedly and to measure the time-varying flow rates during operation. This dynamic testing provides much more insight into valve behavior than the single-pop or continuous flow tests commonly reported. The facility is additionally unique in its simulation of accident conditions as a means of measuring valve performance. Specimen valves for this series represent 20 each of three manufacturers’ design for a semi-internal 1-in. 312 psi LPG relief valve. The purpose of this paper is to present the procedure and results of these tests. No effort is made to perform in-depth analysis into the causes of the various behaviors, nor is any assessment made of the risk presented by any of the valves. [S0094-9930(00)01201-4]

Study on the Relief Capacity and Safety Integrity of Multiple Relief Valves of Charge Gas Pipe in Ethylene-Cracking Plant

2013 ◽  
Author(s):  
Jianxin Zhu ◽  
Xuedong Chen ◽  
YunRong Lu ◽  
Zhibin Ai ◽  
Weihe Guan
Keyword(s):  
Large Scale ◽  
Relief Valve ◽  
Pressure Relief ◽  
Emergency Relief ◽  
Safety Integrity Level ◽  
Upstream Pressure ◽  
Minimum Number ◽  
The Difference ◽  
Relief System

The shutdown of charge gas compressor in large-scale ethylene-cracking plant always involves emergency pressure relief of charge gas through multiple safety valves. The emergency relief capacity plays an important role on the safety of the overall plant. In this paper, by studying the difference between the configuration of the pressure relief system of two 1000 KTA ethylene-cracking plants (the inner diameters of the charge gas pipeline in both plants are 2m, while the number of same-sized relief valves are 28 and 19, respectively), the relief capacity of multiple relief valves is studied and compared with empirical calculation and numerical analysis. It is found that, due to the interruption of fluid flow when compressor is emergency shutdown, the upstream pressure of each relief valve increase steadily with the continuously make-up of the charge gas, but the difference between the inlet pressure of all relief valves can be neglected. With the increase of the upstream pressure, the opening of relief valves is determined mainly by the set pressure. In multiple valves pressure relief scenario, normally the downstream valves have greater relief capacity than those upstream valves if both relief valves have the same back pressure. Also, by analysis it is noted that the pressure relief capacities of multiple relief valves in both plants are sufficient. The minimum number of relief valves required for process safety is obtained. The maximum achievable Safety Integrity Level (SIL) of pressure relief system is determined by calculation of the reliability of the redundant relief valves. The analysis is used for determination of the SIL of the pressure relief system. The finding is also significant for determination of the required capacity of multiple relief valves.

An Assessment of the Validity of Quasi-Steady Analysis of Pressure Relief Valves

2019 ◽  
Author(s):  
Christopher Doyle ◽  
William Dempster ◽  
Steven Taggart
Keyword(s):  
Steady State ◽  
High Fidelity ◽  
Cfd Simulations ◽  
Pressure Relief ◽  
Ansys Fluent ◽  
Interaction Processes ◽  
Transient Simulations ◽  
Flow Features ◽  
Pressure Relief Valves ◽  
Computational Fluid Dynamics Cfd

Abstract In this paper, the validity of the commonly used quasi-steady design approach to pressure relief valves (PRV) is examined by comparing detailed steady state conditions of valve behavior directly with transient conditions. To achieve this, a PRV conforming to ASME VIII standards was modelled using the commercial computational fluid dynamics (CFD) package ANSYS FLUENT to account for transient fluid-structure interaction processes. Detailed steady state CFD simulations were conducted using quasi-steady assumptions and compared to high fidelity transient moving mesh simulations to allow the piston forces to be examined. The results indicated that noticeably different magnitudes can occur between steady state and transient simulations; highlighting the possibility of significant differences occurring between quasi steady designed valves and their ultimate performance. In this paper, a single operating condition is examined, using air at 10.3 barg, for a 5231BX refrigeration valve supplied by the Henry Group to highlight the main issues. Analysis has indicated that the differences in performance are generated by temporal, short lived vortices at the piston surface which influences the bulk flow features as the disc accelerates and decelerates; altering the net disc forces when compared to steady state conditions.

On the Dynamics of Pressure Relief Valves With External Pilot for ICE Lubrication

2014 ◽  
Author(s):  
Massimo Rundo
Keyword(s):  
Frequency Response ◽  
Pressure Relief ◽  
Experimental Procedure ◽  
Pressure Transducers ◽  
Displacement Pump ◽  
Pressure Relief Valves ◽  
The Stability ◽  
Pilot Channel ◽  
New Generation ◽  
Excitation Pressure

The paper analyzes the influence on the stability of the remote pilot in pressure relief valves used for engine lubrication. Such valves are mainly used to discharge the excess flow generated by a fixed displacement pump, moreover they can also be used as pilot stage to control the displacement in the new generation of vane pumps. In the paper the transfer function that relates the pressure in the main gallery with the valve spool position is determined. It was found that, when the valve is provided with an external pilot, the interaction between the hydraulic inductance of the pilot pipe and the spool decreases by many times the mechanical frequency of the valve, leading to a reduction of the stability. The experimental procedure used to measure the frequency response of the valve is also described. The test rig was provided with a servovalve used to generate a sinusoidal excitation pressure with variable frequency. The valve frequency response was evaluated by means of two pressure transducers at the two ends of the pilot channel. Finally the influence on the stability of some geometric parameters is analyzed by means of a simulation model in the AMESim environment.

Analytical Description of the Static and Dynamic Behaviour of a Pressure Relief Valve

2018 ◽  
Author(s):  
Sven Osterland ◽  
Jürgen Weber
Keyword(s):  
Dynamic Behaviour ◽  
Characteristic Curve ◽  
New Method ◽  
Pressure Relief Valve ◽  
Inertia Force ◽  
Relief Valve ◽  
Pressure Relief ◽  
Spreadsheet Program ◽  
Non Linear ◽  
The Stability

The paper presents an explicitly straightforward formulation of the stationary and dynamic behaviour of a pressure relief valve (PRV). This makes it possible to consider the static, dynamic and robustness properties of a PRV during the analysis or design process. A PRV can be understood as a self-regulating, cross-domain system. The governing equations are well known and widely used in literature. Usually, these include: a geometrical description of the flow area and the pressure surface, a flow equation, the pressure build-up equations, a spring-like counterforce, a flow force, a term for viscous friction and the inertia force. Together they form a system of ordinary non-linear differential equations of third order. So far, these equations had to be solved numerically in order to analyse or adapt the static or dynamic properties of a particular PRV. In this paper, direct analytical solutions for stationary and dynamic cases are derived. This results in an explicit equation for the respective p-Q characteristic curve. In addition, a simple criterion for the stability of a PRV was found. As it turns out, the minimum requirement for viscous damping is directly anti-proportional to the gradient of the p-Q characteristic curve. It is empirically known that decreasing the gradient of the p-Q curve makes the system more susceptible to oscillations. However, this has not yet been shown mathematically elegant. The method presented here calculates the static p-Q curve, the stability and natural frequencies of a PRV in a simple procedure using only elementary mathematics — no numerical scheme is required. Thus, the new method offers four main advantages. First, it is several orders of magnitude faster because it is not necessary to solve the differential equation system numerically. Secondly, the user does not require any special knowledge or advanced calculation tools — a simple spreadsheet program is sufficient. This eliminates licensing and training costs. Third, sensitivity and robustness analyses can be carried out easily because the dependencies are explicitly known. Last but not least, the understanding of a PRV is improved by knowing directly which parameters have what influence. The new method is tested and verified by comparison with conventional non-linear numerical simulations.

Naval Standard Safety Valve Design Using CAD Solutions

2014 ◽  
Vol 658 ◽  
pp. 65-70 ◽  
Author(s):  
Constantin Dumitrache ◽  
Ioan Calimanescu ◽  
Corneliu Comandar
Keyword(s):  
Sole Source ◽  
Pressure Relief Valve ◽  
Hydraulic Systems ◽  
Relief Valve ◽  
Pressure Relief ◽  
Working Pressure ◽  
Power Failure ◽  
Process Fluid ◽  
Control Fluid ◽  
System Variables

Apressure relief valveis a safety device designed to protect a pressurized vessel or system during an over-pressure event. An overpressure event refers to any condition which would cause pressure in a vessel or system to increase beyond the specified design pressure or maximum allowable working pressure. Many electronic, pneumatic and hydraulic systems exist today to control fluid system variables, such as pressure, temperature and flow. Each of these systems requires a power source of some type, such as electricity or compressed air in order to operate. A pressure relief valve must be capable of operating at all times, especially during a period of power failure when system controls are nonfunctional. The sole source of power for the pressure relief valve, therefore, is the process fluid.

scholarly journals Statistical Performance Evaluation of Spring Operated Pressure Relief Valve Reliability Improvements 2004 to 2014

2015 ◽  
Author(s):  
Holly L. Watson ◽  
Robert E. Gross ◽  
Stephen P. Harris
Keyword(s):  
South Carolina ◽  
The United States ◽  
Pressure Relief Valve ◽  
United States Department ◽  
Relief Valve ◽  
Pressure Relief ◽  
Maintenance Program ◽  
Operational Systems ◽  
Pressure Relief Valves ◽  
Improved Performance

The United States Department of Energy’s Savannah River Site (SRS) in Aiken, South Carolina, is dedicated to promoting site-level risk-based inspection (RBI) practices in order to maintain a safe and productive work environment. Inspecting component parts of operational systems, such as pressure relief valves (PRVs), is a vital part of SRS’s safe operating envelope. This paper is a continuation of a SRS program to minimize the risks associated with PRV failures. Spring operated pressure relief valve (SOPRV) test data accumulated over the past ten years resulted in over 11,000 proof tests of both new and used valves. Improved performance is seen for air service valves resulting from changes to the maintenance program. Although, statistically significant improvement was not seen for liquid, gas, or steam service valves, analysis shows that the overall probability of failure on demand is trending down. Current SRS practices are reviewed and the reasons for improved performance are explored.

The Design and Research of Automatic Micro-Pressure Relief Valves Used in Mine Rescue Cabin

2015 ◽  
Vol 752-753 ◽  
pp. 828-832
Author(s):  
Nian Yong Zhou ◽  
Yan Long Jiang ◽  
Lei Xu ◽  
Jun Li ◽  
He Xu Wang
Keyword(s):  
Fast Response ◽  
Pressure Relief Valve ◽  
Opening Pressure ◽  
Relief Valve ◽  
Pressure Relief ◽  
Advantages And Disadvantages ◽  
Sealing Performance ◽  
Pressure Relief Valves ◽  
Relief Rate ◽  
Mine Rescue

By analyzing the key technologies of pressure relief valve and comparing the advantages and disadvantages of existing products, liquid sealing automatic micro-pressure relief valve is designed with the properties of adjustable opening pressure, fast response rate, good sealing performance and long life, etc. Also, a reasonable mathematical model of liquid sealing automatic micro-pressure relief valve is developed, and the pressure relief valve’s opening pressure, reset pressure, relief rate and other key performance parameters is obtained. This work wil be helpful for the design and research of automatic micro-pressure relief valves used in mine rescue cabin.

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