Valves are one of the indispensable industrial pipeline accessories in the national economy. They are widely used in pipelines of various fluid engineering systems. It can be said that valves are needed wherever there are industrial pipelines. Regarding the definition of "valve", there are different descriptions in different books. GB/T21465-2008 "Valve Terminology" states that "valve refers to the general name of mechanical products that are used to control the medium in the pipeline and have a movable mechanism."
The "control" function of the valve in the above definition mainly refers to the function of the valve installed on the pipeline to cut off, guide flow, prevent reverse flow, adjust diversion or overflow pressure relief, etc. The "medium" in the definition covers various liquids, gases, granular solids and their combinations.
At the same time, most valve products used in industrial pipelines fall within the scope of pressure pipeline components in the national "Special Equipment Catalog", and their manufacturing processes should comply with the "Special Equipment Safety Supervision Regulations" and TSG
Relevant provisions in D2001 "Manufacturing Licensing Rules for Pressure Pipe Components".
