Needle valve type selection

Needle valve is an important part of the meter in the piping system, mainly cut-off valve and ball valve, its function is used as open or cut off the pipeline pathways. Type needle valve material shall be according to the parameters and material selection of performance according to this standard, and shall comply with the provisions of the relevant product standards. Also can choose the performance is not lower than the provisions of this standard or for other material purchase contract agreed upon. A few introduce Shanghai valves of different material type needle valve selection: malleable cast iron needle type valve used for nominal pressure pN≤ 2. 5 mpa, temperature is & ndash; 30 ~ 300 ℃ medium such as air, steam, water and oil of malleable cast iron valves. Ductile cast iron needle type valve used for nominal pressure pN≤ 4. 0 mpa, temperature for & ndash; 30 ~ 350 ℃ medium such as air, steam, water and oil of ductile cast iron valves. Copper and gold needle type valve used for nominal pressure pN≤ 2. 5 mpa water, sea water, oxygen, air, oil, such as medium, and the temperature for & ndash; 40 ~ 250 ℃ steam medium copper gold valve. Carbon steel needle type valve used for nominal pressure pN≤ 32. 0 mpa, temperature for & ndash; 30 ~ 450 ℃ water, steam, air, hydrogen, ammonia, nitrogen and petroleum products such as medium carbon steel valves. High temperature type steel needle valve used for nominal pressure pN≤ 16. 0 mpa, temperature less than or equal to 550 ℃ steam and oil products such as the heat medium steel valves. Low temperature type steel needle valve used for nominal pressure pN≤ 6. 4 mpa, the temperature is higher than or equal to & ndash; 196 ℃ of ethylene, propylene, liquid, gas, liquid nitrogen medium low temperature steel valves, etc. Acid-proof stainless steel needle type valve used for nominal pressure pN≤ 6. 4 mpa, the temperature is lower than or equal to 200 ℃ of the media such as nitric acid, acetic acid, acid-proof stainless steel valves.