Classification of shut-off valves
Commonly used shut-off valves are as follows:
1) Straight-through stop valve
2) DC type stop valve: In the DC or Y-shaped stop valve, the flow path of the valve body is inclined with the main flow path, so that the degree of damage of the flow state is smaller than that of the conventional stop valve, and thus the pressure loss through the valve is correspondingly Small.
3) Angle stop valve: In the angle cut-off valve, the fluid only needs to change in one direction, so that the pressure drop through the valve is smaller than that of the conventional structure.
4) Plunger shut-off valve : This type of shut-off valve is a variant of a conventional shut-off valve. In this valve, the flap and seat are usually designed based on the principle of the plunger. The valve flap is polished into a plunger that is coupled to the valve stem, and the seal is achieved by two elastomeric sealing rings that are placed over the plunger. The two elastomeric seals are separated by a collar and the seal around the plunger is pressed by the load exerted by the bonnet nut on the bonnet. The elastomeric seal can be replaced and can be made from a wide variety of materials. The valve is mainly used for "opening" or "off", but with a special form of plunger or special collar, it can also be used to regulate flow. . 
Commonly used globe valves are GB shut-off valves , American standard cut-off valves, German standard cut-off valves, Japanese standard cut-off valves, bellows stop valves, and low temperature stop valves.
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