XV PV valve

The XV valve is a shut-off valve; the exact type of valve isn’t specified. Ball valves, globe valves, and butterfly valves can all be used. It has only two positions: open and closed; it cannot be positioned at any intermediate point. In contrast, the PV valve is a control valve that operates based on pressure input. Similarly, there’s also the TV valve for temperature control, the LV valve for level control, and the FV valve for flow control

Teacher, then what controls the XV valve?

In the absence of air pressure, the valve disc of the pneumatic on-off valve remains in a closed position. When an air pump supplies pressurized air to the cylinder of the valve, the valve disc opens. When it is necessary to close the emergency shut-off valve or in an emergency situation, the pressure is released, causing the valve to close quickly and preventing leaks. The flow direction of the medium passing through the valve is such that the valve seat end serves as the outlet; installation typically involves having the high pressure side at the top and the low pressure side at the bottom. If it is a on-site valve to be operated, a handwheel is used; for those that are at a certain distance from the operator, sprockets or an extended rod can be employed. In the case of remote control, a three-position solenoid valve is usually added; by controlling this solenoid valve, the air supply can be cut off or connected, thereby controlling the opening and closing of the valve. Regarding the basics of valves, it is advisable to conduct more research and observations; never be conceited or narrow-minded. https://zhuanlan.zhihu.com/p/64576931

Pneumatic on-off valves also have a condition where, in the absence of air pressure, the valve disc remains in the open position. Whether the non-pressurized state is normally open or normally closed depends on the requirements of the process; the state that is safer is the one that is adopted.