Solenoid valve procurement only clear specifications, categories, work pressure to meet the procurement requirements, in the current market economy environment is not perfect. Because valve manufacturers for product competition, each in the concept of unified design of the valve, to carry out different innovations, formed their own corporate standards and product personality. Therefore, in the purchase of the valve more detailed technical requirements, coordination with the manufacturers to obtain a consensus, as an attachment to the valve procurement contract is very necessary.
1. General requirements
1.1 The solenoid valve valve specifications and categories should meet the requirements of the pipeline design documents.
1.2 solenoid valves Valve models should be specified based on the national standard number requirements. If it is a corporate standard, the description of the model should be specified.
1.3 solenoid valve work pressure, requirements ≥ pipe working pressure, under the premise of not affecting the price, the valve can withstand the pressure should be greater than the actual pressure of the pipeline; valve closure on either side should be able to withstand 1.1 times Valve pressure value without leakage; solenoid valve open conditions, the valve body should be able to withstand the requirements of double the valve pressure.
1.4 solenoid valve manufacturing standards, should be based on the national standard number, if corporate standards, the procurement contract should be attached to corporate documents.
2. solenoid valve valve quality
2.1 solenoid valve body material, should be based on ductile iron, and indicate the actual physical and chemical testing data of grade and cast iron.
2.2 solenoid valve stem material, stainless steel valve stem (2CR13), large-diameter valve should also be stainless steel embedded valve stem.
2.3 Nut material, using cast aluminum brass or cast aluminum bronze, and hardness and strength are greater than the valve stem.
2.4 BURKERERT solenoid valve stem bushing material, its hardness and strength should not exceed the stem, and in the water immersed condition and stem, valve body does not form electrochemical corrosion.
2.5 The material of the sealing surface: 1 The valve type is different, and the sealing method and material requirements are different; 2 Ordinary wedge gate valve, the material of the copper ring, the fixing method and the grinding method should all be explained; 3 The soft sealing gate valve and the valve plate rubber lining material Physical and chemical testing data; solenoid valve should be marked on the valve body sealing surface material and disc surface sealing material; their physical and chemical testing data, especially the rubber hygiene requirements, anti-aging properties, wear resistance; usually NBR, EPDM, etc. are strictly prohibited, and reclaimed rubber is strictly prohibited.
2.6 solenoid valve shaft filling: 1 due to the valve in the pipe network, usually open and close infrequent, requiring the filler to be inactive for several years, the filler is not aging, long-term maintain the sealing effect; 2 valve shaft packing should also be under Frequent opening and closing, the sealing effect is good; 3 in view of the above requirements, the valve shaft packing strives for a lifetime without replacement or replacement for more than 10 years; 4 if you need to replace the filler, the valve design should consider the possibility of replacement under the condition of water pressure .
3.1 The box material and internal and external corrosion requirements are consistent with the valve body principle.
3.2 The enclosure should have sealing measures. After the cabinet is assembled, it can withstand the immersion of 3 meters of water column.
3.3 The opening and closing limit device on the box, the adjustment nut should be in the box or located outside the box, but the need for special tools to work.
3.4 The transmission structure is reasonable in design. When the valve is opened and closed, it can only drive the valve shaft to rotate. It does not make it move up and down, and the transmission parts are suitable for biting. It does not produce separation and skidding when the load is opened and closed.
3.5 The transmission housing and valve shaft seal can not be connected into a leak-free whole, otherwise there should be a reliable anti-string leakage measures.
3.6 There are no sundries in the box, and the gear bite should be protected by grease.
4. solenoid valve operating mechanism
4.1 solenoid valve opening and closing direction when the valve, should be closed clockwise.
4.2 Since the valves in the pipeline network are often manually opened and closed, the number of rotations for opening and closing should not be too much, that is, large-diameter valves should be within 200-600 rotations.
4.3 In order to facilitate a person's opening and closing operations, the maximum opening and closing moment should be 240N-m under the condition of pipeline pressure.
4.4 solenoid valve valve opening and closing operation end should be square, standard size, and facing the ground, so that people can directly operate from the ground. Wheeled valves are not suitable for underground pipe networks.
4.5 solenoid valve valve opening and closing degree of the display panel: 1 valve opening and closing degree of the scale line, should be cast on the transmission cover or conversion direction after the display panel shell, are all facing the ground, the scale line brushed with phosphor, To show eye-catching; 2 indicates the material of the plate pin can be used in the case of better management of stainless steel plate, otherwise painted steel plate, do not use aluminum skin production; 3 indicates that the plate pin is eye-catching, fixed firmly, once the opening and closing adjustment is accurate Should be locked with rivets.
4.6 If the solenoid valve is deeply buried and the distance between the operating mechanism and the display panel is ≥ 1.5m from the ground, an extension rod facility shall be provided and it shall be fixed firmly so that people can observe and operate from the ground. In other words, the valves in the pipe network are opened and closed, so it is not suitable to go downhole.