Working principle of pneumatic globe valve:
Pneumatic globe valve is a valve with compressed air as the power source. It adopts remote control, and the main control room manually or automatically triggers the action command to make the air inlet and exhaust solenoid valve act and supply and exhaust compressed air to the actuator. The compressed air acts on the piston or diaphragm to overcome the friction of valve action and spring force on the valve stem, so as to press down (for valve opening due to loss of air) or lift up (for valve closing due to loss of air) the valve stem and drive the valve core to move up and down to open or close the valve.
When the valve loses air and there is no compressed air in the driving head, the valve will be in the safe position of full opening or full closing according to the requirements of the system. For instrument compressed air for power plant, the air supply pressure is generally 4-9bar. Before entering the valve, filter and purify the compressed air through the filter, and then reduce the pressure through the pressure reducing valve. The reading of the inlet pressure gauge is not more than 4bar. The pressure adjustment can be realized by adjusting the adjusting screw installed on the top of the pressure reducing valve, and the protective cover shall be loosened before the adjustment.
Installation instructions for pneumatic globe valve:
Pneumatic globe valve is usually used in the fully closed and fully open gas and liquid one-way flow pipeline, its structure is longer than the gate valve, the length is shorter. When the medium is highly corrosive, the stop valve with low inlet and high outlet shall be selected. When the medium pressure is high or the valve is often opened and closed, the valve rod shall be thickened to avoid the bending of the valve rod caused by the medium thrust. Compared with other valves, the flow resistance of pneumatic stop valve is greater. In the use process, attention should be paid to the pressure of air source and the problem of pressure and corrosion resistance on the valve stem. Pneumatic stop valve is not suitable for medium with particles, high viscosity and easy coking.