The valve standard regulates the requirements of the valve design, manufacture, inspection and use, so that both the manufacturing and the use have a common language, and can protect their respective interests from the perspective of technical regulations, so that the judgment has a unified standard. In the past, some small enterprises did not put the quality problem first, the length of the valve body was different, the valve material was not up to standard, and the sealing material was poor, which caused the inconvenience and operational safety risk of the installation of the pipeline project. The procurement is negligent, there is no clear standard in procurement, resulting in loopholes in procurement supply!).
The current valve quality has the following problems:
Defect in valve casting
The valve body material carbon steel, especially the chrome molybdenum steel valve body is prone to sand, burrs and fine cracks during the casting process, and the appearance is rough. Friends who sell in the outside know that when the customer accepts the goods, the small trachoma glitch will lead to the customer's acceptance failure, a large number of valves have to be returned, and many sales do not understand, so what is the relationship between a small trachoma and a small burr? It does not affect the use, it is a bit ugly. But the experience of using the unit tells them that quality is not only about valves, but also about attitudes.
The tightness of the valve is an important indicator of the function and quality of the valve. The problem of internal leakage of the valve is serious, threatening the normal operation of the entire engineering device, and it is difficult to find whether there is an internal leakage in the running valve. Most of the reasons for using the internal leakage of the unit valve are that the sealing surface material of the valve plate and the valve seat does not meet the requirements for use, the machining accuracy is not enough, the wedge angle of the valve plate and the valve seat of the gate valve is not matched, the sealing surface width is narrow, and the fitting degree is poor, the gate is not in place, the door is not dead and other factors. There is also a packing packing assembly that does not meet the requirements, resulting in leakage.