An Introduction to Pneumatic Valves

A pneumatic valve is a valve driven by compressed air. It can be used to control the fluid flow such as air, water, steam, corrosive media, mud, oil, liquid metal and radiating media. The pneumatic valve should be installed horizontally in the pipeline.

1. Main Classes of the Pneumatic Valve

(1) Pneumatic V-type adjusting ball valve
(2) Pneumatic O-type cut-off ball valve
(3) Torque type cylinder ball valve
(4) Electromagnetic diaphragm valve
(5) Pneumatic straight-through diaphragm valve
(6) Electric valve

2. Materials of the Valve Part

(1) The valve body shall be made from ductile iron, and the brand and actual physical and chemical testing data of cast iron shall be indicated.

(2) Materials of the valve stem should be stainless steel.

(3) The nut is made from casting aluminium brass or casting aluminium bronze, and its hardness and strength are greater than those of the valve stem.

(4) The hardness and strength of the valve stem bush shall not be greater than those of the valve stem, and electrochemical corrosion will not occur to the stem and the valve body under the condition of water immersion of the valve stem bush.

3. Valve Shaft Packing

(1) Because the pneumatic valve in the pipe network is usually not opened and closed frequently, which requires the packing not to be active for several years and meanwhile the material is not aging, and the sealing is maintained good for a long time.

(2) The valve shaft packing should also keep a good seal when the valve is frequently opened and closed.

(3) In view of the above requirements, the valve shaft packing should not be replaced for life or for more than ten years.

(4) The packing needs to be replaced under the condition of water pressure.