Structural principle of direct single seat valve

Structural Principles

The straight through single seat regulating valve has a valve core and a valve seat. The valve stem is connected to the valve core, and when the actuator moves in a straight line, it drives the valve core to move through the valve stem. The upper cover plate is used to compress the packing, and the upper valve cover is connected to the valve body with bolts for central positioning of the valve stem and valve core. The valve seat and upper valve cover are used together to ensure the center positioning of the valve core and valve seat, and to change the flow area of the fluid when the valve core moves, thereby changing the control variable and achieving the function of regulating fluid flow. The valve core in the figure is guided by the top guidance method. Some straight-through single seat valves adopt a top bottom guidance method to improve guidance accuracy. Some small flow direct control valves often use seat guidance.

 

Characteristic

1. Low leakage, easy to achieve strict sealing and cutting, for example, hard metal to metal sealing or soft metal to PTFE based composite materials can be used, with a standard leakage of 0.01% C (C is the rated flow coefficient).

2. Low allowable pressure difference

3. Low circulation capacity

4. Due to the high thrust of the fluid medium on the valve core, i.e. the large imbalance force, it is not suitable to use this type of control valve in high-pressure differential and large-diameter applications