A check valve is a valve whose opening and closing parts are opened or closed by the force of the flow to prevent the backflow of the medium. The check valve belongs to automatic valves, which is used for pipelines with a single flow. The quality of the check valve is very important. The normal and continuous work of the check valve guarantees the operation of the project. Therefore, the quality inspection of the check valve in advance can achieve the purpose of safe operation. Therefore, how do you test the check valve?
Testing lift check valves
There are three steps for testing lift check valves, which are as follows:
1. Open the check valve's passage, and fill the valve cavity with water or kerosene; increase the pressure to the pressure required by the strength test, and check whether or not there is a leakage at the valve body, valve bonnet, gasket and packing.
2. Close the check valve and pressurize one side of the check valve to the nominal pressure; check for leakage from the other side.
3. Turn the check valve upside down and test the opposite side.
Through the above three simple steps, we can know whether the basic working state of the check valve is abnormal.
Testing cast steel swing check valves with American standards
The steps for testing swing check valves are as follows:
1. The nominal pressure of the check valve should be from 0.4Mpa to 32Mpa, and the strength test pressure is 1.5 times higher than its nominal pressure. The valve's sealing test pressure is equal to 1.1 times the nominal pressure.
2. The check valve's test bench usually has a pressing part on the top and a pipeline connected to the pressure test pump below. After the valve is pressed, the pressure test pump works, and the pressure of the valve can be read from the pressure gauge of the pressure test pump. When the electric valve is pressure tested and filled with water, the air in the valve should be drained. The upper pressure plate of the test bench has an exhaust hole, which is opened and closed by a small valve. The water coming out from the exhaust hole shows that the air is removed completely. After closing the exhaust hole, start boosting. The boosting process should be slow. After reaching the specified pressure, keep it for 3 minutes. If the pressure remains unchanged, the valve passes the test.
Testing lift check valves
There are three steps for testing lift check valves, which are as follows:
1. Open the check valve's passage, and fill the valve cavity with water or kerosene; increase the pressure to the pressure required by the strength test, and check whether or not there is a leakage at the valve body, valve bonnet, gasket and packing.
2. Close the check valve and pressurize one side of the check valve to the nominal pressure; check for leakage from the other side.
3. Turn the check valve upside down and test the opposite side.
Through the above three simple steps, we can know whether the basic working state of the check valve is abnormal.
Testing cast steel swing check valves with American standards
The steps for testing swing check valves are as follows:
1. The nominal pressure of the check valve should be from 0.4Mpa to 32Mpa, and the strength test pressure is 1.5 times higher than its nominal pressure. The valve's sealing test pressure is equal to 1.1 times the nominal pressure.
2. The check valve's test bench usually has a pressing part on the top and a pipeline connected to the pressure test pump below. After the valve is pressed, the pressure test pump works, and the pressure of the valve can be read from the pressure gauge of the pressure test pump. When the electric valve is pressure tested and filled with water, the air in the valve should be drained. The upper pressure plate of the test bench has an exhaust hole, which is opened and closed by a small valve. The water coming out from the exhaust hole shows that the air is removed completely. After closing the exhaust hole, start boosting. The boosting process should be slow. After reaching the specified pressure, keep it for 3 minutes. If the pressure remains unchanged, the valve passes the test.
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