Standard quality of pneumatic gate valve

Pneumatic gate valve:A valve driven by compressed air. Pneumatic gate valve procurement only clear specifications, categories, pressure to meet the procurement requirements, in the current market economy is not perfect. Because the pneumatic gate valve manufacturers in order to product competition, each in the unified design of pneumatic valve ideas, different innovations, the formation of their own corporate standards and product personality. Therefore, in the procurement of pneumatic gate valves to put forward detailed technical requirements, and manufacturers to coordinate to reach consensus is very necessary, as an annex to the pneumatic gate valve procurement contract.
General requirements are as follows:

　　1. The specifications and types of pneumatic gate valves should meet the requirements of the pipeline design documents.

　　2. The model number of the pneumatic gate valve should be indicated in accordance with the requirements of the national standard number. If it is a corporate standard, the relevant description of the model should be indicated.

　　3. Pneumatic gate valve working pressure is greater than the pipeline working pressure, without affecting the price, the pressure that the valve can withstand should be greater than the actual pressure of the pipeline; any side of the pneumatic gate valve should be able to withstand 1.1 times the valve pressure value without leakage; valve open state, the valve body should be able to withstand twice the valve pressure requirements.

　　4. Pneumatic gate valve manufacturing standards, should be stated based on the national standard number, such as corporate standards, procurement contracts should be attached to corporate documents.

　　5. Pneumatic valve standard quality valve body material for ductile iron, cast steel, stainless steel, 316L, and specify the grade and the actual physical and chemical test data of cast iron.

　　6. Stem material, strive to stainless steel stem (2CR13), large diameter valves should also be used in stainless steel embedded stem.

　　7. Nut material, using cast aluminum brass or cast aluminum bronze, hardness and strength greater than the stem.

　　8. Stem bushing material, its hardness and strength should not be greater than the stem, and in the conditions of water immersion with the stem, the valve body does not form electrochemical corrosion.

　　9. sealing surface material.

　　10 different types of pneumatic gate valves, sealing methods and material requirements are different; common wedge-shaped gate valve, copper ring material, fixing method, grinding method should be described.

　　11. Physical, chemical and sanitary test data of soft seal gate valve and valve plate lining materials.

　　12 pneumatic gate valve should be specified on the valve body sealing surface material, on the butterfly plate sealing surface material; its physical and chemical test data, especially the health requirements of rubber, anti-aging properties, wear resistance; usually use nitrile rubber and EPDM rubber, mixed with recycled rubber is strictly prohibited. Valve shaft packing.

　　13. Since pneumatic valves in the pipeline network usually rarely open and close, the packing is required to be inactive for several years, the packing does not age, and the sealing effect is maintained for a long time.

　　14. The valve spool packing should also withstand frequent opening and closing with good sealing effect.

　　15. For the above requirements, the valve spool packing life does not change or more than ten years.

　　16. If the packing needs to be replaced, the pneumatic valve design should consider the replacement measures under water pressure conditions.

　　17. Variable speed transmission box box material and internal and external anti-corrosion requirements in line with the valve body principle. The box body should be sealed and can withstand the immersion of 3m water column after assembly.

　　18. The opening and closing limit device on the box body, its adjusting nut should be inside or outside the box body, but special tools are needed to work. Transmission structure is reasonably designed, opening and closing can only drive the valve shaft rotation, do not make it move up and down, transmission parts bite moderate, do not produce load opening and closing separation slip.

　　19. Gearbox and valve shaft seal can not be connected into a leak-free whole, otherwise there should be reliable anti-leakage measures. No debris in the box, gear bite parts should be protected with grease.