Understand the stainless steel gate under the general test requirements
Understand the general testing requirement of stainless steel gate under a, general requirements for the valve 1.
The valve specifications and categories, should accord with the requirement of pipe design documents.
Valve type shall be marked according to gb code requirements.
If the enterprise standards, should indicate the type of relevant specification.
Valve working pressure and requirement & ge;
Pipe work pressure, without affecting the price under the premise of the valve can withstand work pressure should be greater than pipeline of actual work;
The valve closed condition should be able to withstand any side 1.
Double valve pressure value, without leakage;
Open valve, the valve body shall be able to withstand 2 times the working pressure of valve requirements.
Valve manufacturing standards, should be according to gb code, if the enterprise standards, on the purchase order file should be attached to the enterprise.
Second, the valve material 1.
The valve material, use gradually is not recommended because of the gray cast iron pipe, valve body material should give priority to with nodular cast iron, and indicate the brand and the physical and chemical testing data of the casting practice.
Stem material, and strive to stainless steel stem, large diameter valves should also be embedded package of stainless steel stem.
Nut material, the use of cast aluminum bronze, brass or aluminum and hardness and strength were greater than the valve stem.
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.
Valve sealing surface of the material (1) 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;
Usually adopt butyl eyes rubber and epdm and so on, are strictly forbidden to mixed with reclaimed rubber.
Valve shaft packing (1) as the valve in the pipe network, is 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, valve design should be considered to have the water pressure under the condition of change of measures.