The principle of the pneumatic valve and role

Pneumatic valve is driven by means of compressed air valve. Pneumatic valve when buying only clear specification, category, work pressure could satisfy the requirement of procurement is a method of gas, in the current market economy environment is not perfect. Because of pneumatic valve manufacturer for the product competition, each under the conception of pneumatic valve and unified plan, for different innovation, formed their own enterprise standards and product personality. So when pneumatic valve procurement detailed technical requirements, coordination with manufacturer agreement, procurement contract as pneumatic valve attachment is very necessary. This valve shall generally be installed in the pipeline. General requirements for pneumatic non-return valve 1, the production of pneumatic valve specifications and categories, should accord with the requirement of pipe design documents. 2, pneumatic valve type shall be marked according to gb code requirements. If the enterprise standards, should indicate the type of relevant specification. 3, pneumatic non-return valve working pressure and requirement of pipe or work pressure, without affecting the price under the premise of the valve can withstand work pressure should be greater than pipeline of actual work; Pneumatic valve closed condition should be able to withstand any side 1. 1 times the working pressure of valve value without leakage; Open valve, the valve body shall be able to withstand 2 times the working pressure of valve requirements. 4, pneumatic valve manufacturing standards, should be according to gb code, if the enterprise standards, on the purchase order file should be attached to the enterprise. Pneumatic valve material 1, body material, should give priority to with nodular cast iron, and indicate the brand and the physical and chemical testing data of cast iron practice. 2, the valve stem material, and strive to stainless steel stem ( 2CR13) , large diameter valves also should be embedded package of stainless steel stem. 3, nut material, using aluminum brass or aluminum bronze, and the hardness and strength were greater than the valve stem. 4, the valve stem bushing material, its hardness and strength shall be no greater than the valve stem, and soaking in the water condition and the valve stem, valve body don't form the electrochemical corrosion. 5, and materials of sealing surface differ: 1) pneumatic check valves have different categories, different sealing methods and material requirements; (2) normal wedge gate valve, the material of copper ring, fixed way and grinding way shall specify; (3) soft-sealing gate valve, valve plate rubber lining material physical chemistry and health testing data; (4) butterfly valves shall be marked on the valve body sealing materials and sealing surface on the butterfly plate material; Their physical and chemical testing data, especially the health requirements of rubber, ageing resistance, wear resistance; It is forbidden to mixed with reclaimed rubber. 6, valve shaft packing: (1) due to pipe network in pneumatic valve, usually open/close not frequent, packing in a few years no activity, the packing is not aging, long sealing effect; (2) valve shaft packing should also be under the frequent opening and closing, good seal effect; (3) in view of the above requirements, the valve shaft packing to lifetime don't change or more than ten years will not be changed; (4) packing if need to change, design should be considered to have hydraulic pneumatic valve replacement under the condition of measures.