Design and Application of Safety Engineering Pressure Valve Test System Zhang Jianci, Wu Xuemei, Zhang Mo (Zhejiang University of Technology, West Zhejiang Branch, 324004) (Zhejiang Juhua Sulfuric Acid Plant, 324006) Test Project and Method.
1 Introduction Failure is a state of hydraulic components. Products may fail at all stages of trial production, production, use, and maintenance. The meaning of faults and failures for repairable products is the same. In order to improve product reliability, it is often necessary to The product undergoes failure physics analysis. The purpose of this analysis is to find out the failure mode of the product, identify the cause of the failure, study the failure mechanism, estimate the extent to which the failure affects the product, and seek ways to improve product reliability.
Failures can be classified into design failures. Production failures and operational failures Design failures are caused by errors in the design, such as the strengths of the design principles and errors in the structure; and productive failures caused by improper production, such as materials that do not conform to Requirements, in violation of the production process specification, improper use of accessories, etc.; operational failure is caused by the failure to meet the requirements for the use of hydraulic components, such as violation of operating procedures, oil pollution, parts aging, wear, etc. Design failures and productive failures may be discovered at the factory's testing stage or at the beginning of the product's operation, while operational failures may occur at the early stages of operation, but most occur throughout the entire operation.
For pressure valves in hydraulic systems, there are no exceptions. To ensure the normal operation of equipment, including pressure safety and pressure protection, and to perform overload protection and pressure loss protection, we should take various measures to protect the valve from failure. The set of pressure valve test hydraulic system can accurately grasp the working performance and status of the pressure valve.
2 pressure valve test hydraulic system pressure valve test hydraulic system as shown 6-reversing valve; 7,8-pressure gauge; 9-reversing valve; 10-pressure joint 3 relief valve test items and methods before testing The system makes adjustments: The valve 9 is operated to make the valve 9's personal and equipment safe. Therefore, the pressure must be correctly detected in the connected state (lower position), the valve 6 is in the left position, the valve 5 is in the left position, and the system enters the overflow. Valve test status.
3.1 Pressure regulation range and pressure stability test Test method: Adjust the pressure of the relief valve 2 to the maximum pressure of the test valve by 10%, and make the test valve pass the test flow, and perform the following tests respectively: (1) The adjustment is The pressure regulating handwheel of the test valve is fully open to fully closed, and then fully closed to fully open. The pressure rise and fall and the pressure regulation range are measured by the pressure gauge 7 and the test is repeated 3 times.
(2) Adjust the test valve to the highest regulation pressure and the pressure gauge 7 to measure the pressure fluctuation value.
(3) Adjust the test valve to the highest regulation pressure. Measure the pressure offset value within 1min from the pressure gauge (1) The pointer of the pressure gauge 7 should rise and fall steadily. The adjustment pressure should meet the specified adjustment range 3.2. Test test method: adjust the pressure regulating handwheel of the test valve to the fully closed position, adjust the overflow valve 2, the system pressure is the highest adjustment pressure of the tested valve and then adjust the pressure adjustment handwheel of the test valve, make the tested valve After opening and closing completely, the leak test within the overflow port of the test valve shall be tested. Requirements: The internal leakage of the overflow valve shall not exceed the specified value.
3.3 Unloading pressure test Test method: When the remote relief valve is tested, the test valve passes the test flow, and the relief valve remote port is connected to the fuel tank to measure the pressure from the pressure gauge 78. The difference is the test valve. When the unloading pressure of nine pairs of electromagnetic relief valve is tested, the tested valve passes the inspection flow and the electromagnet of the tested valve is energized (or de-energized). The pressure is measured by the pressure gauge 78, and the difference is the tested Valve unloading pressure 3.4 Pressure loss test Test method: Adjust the pressure regulating handwheel of the test valve to fully release, and make the test valve pass the test flow, and the pressure is measured by the pressure gauge 7 and the pressure gauge 8, and the difference is Test pressure loss test requirements for the valve: only for direct-controlled pressure relief valve and remote pressure regulator valve test, pressure loss shall not exceed the specified value of 3. 5 open and close characteristics test Test method: Close the relief valve 2, the adjustment was Test valve to the maximum adjustment pressure, and test valve through the test flow, adjust the overflow valve 2, the system gradually reduced pressure, when the pressure drops to the test valve closing pressure, measure the test valve overflow. Adjust the relief valve 2 to measure the overflow of the test valve when the test valve does not overflow.
Test requirements: Only the relief valve and the electromagnetic relief valve are tested. The overflow flow through the tested valve under the closing pressure and opening pressure shall not exceed the specified value. 3.6 Operational reliability test Test method: Adjust the test valve to the highest regulation pressure , and to test the flow through the test valve, the remote port of the test valve through the tank, the pressure gauge 7 to measure the unloading (or pressure) of the test valve, repeated testing 3 times; in the pressure connector 10 connection pressure The relay uses an electric stopwatch to measure the pressure rise time; or a pressure sensor is connected to the pressure connector 10 and the pressure rise time is measured using an oscilloscope.
Test requirements: Only the electromagnetic relief valve is tested. When the electromagnet is energized (or de-energized), the system can unload (or boost) in time without squeaking or violent vibration. The pressure recovery time must not exceed the specified value. . 3.7 Back pressure test Test method: Adjust the throttle valve 4, establish the back pressure of Q 5MPa, observe the external leakage of the pressure regulating bolt of the test valve. Test requirements: No external leakage phenomenon 3.8 The static characteristics of the relief valve and Dynamic characteristics The static characteristics of the relief valve can be divided into pressure difference - flow characteristics and pressure - flow characteristics of two types For relief valve, is the opening and closing characteristics of the dynamic characteristics of the relief valve refers to the flow step change, was The pressure response of the test valve is specifically designed to facilitate comparison and to ensure the quality of the step signal in the hydraulic valve.
Test requirements: Valve 2 cannot leak oil and open.
4 Conclusion The pressure valve test hydraulic system, suitable for pressure relief valve, pressure reducing valve, sequence valve and other pressure valve testing This article due to limited space, only expounded the overflow valve performance test methods.
This system can carry out the quality inspection of the pressure valve, check the hydraulic equipment in the process of regular maintenance, fault diagnosis and maintenance, and can also be used as experimental equipment in colleges and universities. Therefore, it is of practical value.
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