Pressure Test Before Valve Dispatch

Valve Performance Testing Method:
1Intensive Strength Test:
Valves can be considered as pressure vessels, thus they must meet the requirement of withstanding medium pressure without leakage. Therefore, the blanks of parts such as valve bodies and covers should not contain defects that affect strength, such as cracks,疏松 pores, inclusions, etc. In addition to conducting strict inspections of the surface and internal quality of the blanks, valve manufacturing factories should also perform strength tests on each unit to ensure the performance of the valves.
Tensile tests are generally conducted after the overall assembly. For parts with unstable rough casting quality or those requiring heat treatment after welding repairs, intermediate strength tests (commonly referred to as rough pumps) can be performed after the rough machining to avoid and minimize waste caused by non-conforming tests. After the parts have undergone the intermediate strength test and the overall assembly, if no requirements are specified by the customer, the valves may no longer need to be subjected to strength tests. To ensure quality, Su Valve conducts full strength tests on all valves after the intermediate strength test.
Tests are typically conducted at room temperature, and to ensure safe usage, test pressuresPTypically for nominal pressurePNNo Chinese content provided.1.25~1.5During testing, the valve was in the open position, one end sealed, with the medium injected from the other end and pressure applied. The exposed surfaces of the casing (body, lid) were inspected, requiring compliance with the specified test duration (usually not less than...).10No leakage within a minute indicates the valve has passed the strength test. To ensure the reliability of the test, it should be conducted before the valve is painted, and the air inside the cavity should be completely drained when water is used as the medium.
Leaking valves, if permitted by technical specifications to be rewelded, should be repaired in accordance with the technical standards. However, a new strength test must be conducted after the repair, with the test duration appropriately extended.


2Sealing Test:
In addition to the throttle valve, both cutting-off valves and regulating valves should possess certain sealing properties. Therefore, each valve must undergo a sealing test before leaving the factory. Valves fitted with seals also require an upper sealing test.
Tests are typically conducted at ambient temperature and at nominal pressure.PNBeing conducted, generally speaking.1.1BaiPNUnder pressure.
When using water as the test medium, it is prone to cause rust on valves. It is usually necessary to control the water quality according to technical requirements and dry or bake the residual water after the test. Gate valves and ball valves, due to having two sealing pairs, require bidirectional sealing tests. During testing, first open the valve, seal one end of the passage, introduce pressure from the other end, close the valve when the pressure reaches the specified value, and then gradually release the pressure at the sealed end while inspecting. Repeat the above test on the other end. Another testing method for gate valves is to maintain the test pressure within the body cavity and simultaneously check the double sealing of the valve from both ends of the passage.