Pneumatic valve which material to use gas

domestic commonly used gas can be divided into four kinds: natural gas, liquefied petroleum gas, artificial coal gas and liquefied petroleum gas and air mixture, which minimizes the corrosive gas, liquefied gas, the largest is the artificial coal gas, corrosion in the artificial coal gas mainly sulphur dioxide, naphthalene, coal tar and other harmful substances. Natural gas can use pneumatic valve material without special requirement, if you use the ordinary carbon steel, surface treatment must do to prevent rust. However, in the artificial coal gas had better not use ordinary copper with pneumatic valve, it becomes copper sulfate, and sulfur dioxide in water after the corrosion of parts is very large. To say is; The artificial coal gas in pneumatic valves and piping is very easy to knot naphthalene, is a kind of white crystal, very hard, is not easy to get rid of, affect the pneumatic valve closed and open it. Coal tar sticky in pneumatic valves and piping is everywhere, very difficult to clean up. At present, there is no good way to solve. The artificial coal gas with low pressure can use pneumatic valve pneumatic valve body is cast iron, high pressure medium can use nodular cast iron, can use the casting stainless steel ( ） 。 Had better not use common cast steel. Pneumatic control valve rubber diaphragm chamber shell is best not to use stamping steel structure, must use, internal to do more advanced surface treatment ( Such as: nickel phosphorus chemical plating, etc. ) 。