Essential for valve sales personnel
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Essential for valve sales personnel 1?General requirements\" 1.1 The specifications and categories of valves must meet the requirements specified in the pipeline design documents. `- 1.2 The model of the valve shall indicate the relevant national standard number requirements. If it is a corporate standard, relevant specifications for the model should be indicated. 1.3 The operating pressure of the valve must be ≥ the operating pressure of the pipeline; provided that it does not affect the price, the pressure that the valve can withstand should be higher than the actual operating pressure of the pipeline ； Either side of the valve when it is closed should be able to withstand 1.1 times the working pressure of the valve without leaking ； With the valve open, the valve body shall be able to withstand a pressure equal to twice the operating pressure of the valve. 1.4 Valve manufacturing standards shall specify the corresponding national standard numbers; if it is a corporate standard, the relevant corporate documents shall be attached to the purchase contract. 2? Valve material 2.1 Regarding the valve material, since gray cast iron pipes are increasingly discouraged for use, the valve body should be made of ductile iron, with the grade specified along with the actual physical and chemical test data of the casting. 2.2 As for the valve stem material, stainless steel stems (2CR13) are preferred; valves with large diameters should also have valve stems covered with stainless steel. 2.3 The material of the nut is cast aluminum brass or cast aluminum bronze, with hardness and strength both greater than those of the valve stem. 2.4 The material of the valve stem bushing should have a hardness and strength that are not greater than those of the valve stem, and it should not cause electrochemical corrosion with the valve stem and valve body when exposed to water. 2.5 Material of the sealing surface: ① Different types of valves require different sealing methods and material specifications ； lLUGx|& 4Q ② Ordinary wedge-type gate valve: the material of the copper ring, the method of fixation, and the grinding method should all be specified ； 6K1Ug,U. ③ Soft-sealed gate valve: Physicochemical and hygiene test data of the rubber lining material used for the valve disc ； ④ The butterfly valve should indicate the material of the sealing surface on the valve body and the material of the sealing surface on the butterfly disc ； Their physicochemical test data, particularly the hygiene requirements for rubber, aging resistance, and wear resistance ； Nitrile rubber and EPDM are commonly used; the use of recycled rubber is strictly prohibited. 2.6 Valve stem packing ① Since the valves in piping systems are usually not operated frequently, it is required that the packing remain intact for several years, without deteriorating and maintaining its sealing properties over time ； yD% ② The packing of the valve shaft should also maintain good sealing performance when subjected to frequent opening and closing ； ? ③Given the above requirements, the valve shaft packing is designed to remain unchanged for the entire lifetime of the device, or at least for over a decade ； ? ④ If the packing needs to be replaced, the valve design should take into account measures for replacement under water pressure
3? Transmission gearbox 3.1 The material of the gearbox casing, as well as the requirements for internal and external corrosion protection, are in line with those applicable to valve casings. ? 3.2 The enclosure shall have sealing measures, and it must be able to withstand immersion under a 3-meter water column pressure after assembly. ? 3.3 The adjustment nut of the opening/closing limit device on the box should be located inside the box. 3.4 The transmission structure is reasonably designed; it allows only the valve shaft to rotate during opening and closing, preventing it from moving up and down. The engagement between the transmission components is appropriate, so there is no separation or slippage when operating under load. ? 3.5 The transmission housing and the valve shaft seal must not be combined into a leak-free unit. ? 3.6 There should be no debris inside the box, and the gear engagement areas must be protected with lubricant. ?zR> 4? Valve operating mechanism? !L#0C :& 4.1 The direction in which the valve should be closed during operation is always clockwise. ? 4.2 Due to the valves in the pipeline network, which are often operated manually, the number of rotations per operation should not be excessive; even for large-diameter valves, this should remain within the range of 200–600 rotations. 3 4.3 To facilitate operation by a single person, under normal piping conditions, the maximum opening and closing torque should be 240 Nm. 4.4 The operating end of the valve should be square-notched, with standardized dimensions, and face the ground so that it can be operated directly from the ground. Valves with wheels are not suitable for underground pipeline networks. 4.5 Display panel for the degree of valve opening and closing ① The scale lines indicating the degree of valve opening and closing should be cast on the gearbox cover or on the housing of the display panel after direction change; they must all face downward. The scale lines are coated with fluorescent powder to ensure visibility ； ? 2r|\M9u8.7 ② The material of the dial needle can be stainless steel in cases where proper management is ensured; otherwise, it should be painted steel. Aluminum sheet shall not be used for its fabrication ； ? ND U>2 ?^ ③ The dial needle is clearly visible and firmly fixed; once the adjustment is accurate, it should be locked in place with rivets. L
5? Performance testing of valves?D3dK8 5.1 When valves of a certain specification are manufactured in bulk, an authoritative institution should be commissioned to conduct tests on the following performance aspects:? ① The opening and closing torque of the valve under operating pressure； _A ②The number of consecutive opening and closing cycles under working pressure that can still ensure a tight seal of the valve ； ? ③ Detection of the flow resistance coefficient of the valve under pipeline water conveyance conditions. ? 5.2 Before leaving the factory, the valves shall undergo the following tests: ① With the valve in the open position, the valve body shall be subjected to an internal pressure test equal to twice the working pressure of the valve ； ? ;W=% { When the valve is closed, each side is subjected to a pressure equal to 1.1 times the working pressure of the valve, with no leakage ； However, for butterfly valves with metal seals, the leakage rate is also no greater than the relevant requirements. 6? Internal and external anti-corrosion treatment of valves 6.1 On the inside and outside of the valve body (including the gearbox), sandblasting should be carried out first to remove rust, followed by the application of electrostatic spraying of non-toxic powdered epoxy resin, with a thickness of at least 0.3 mm. When it is difficult to use electrostatic spraying with non-toxic epoxy resin for extra-large valves, similar non-toxic epoxy paint should be applied by brushing or spraying. ? 6.2 The interior of the valve body as well as all parts of the valve disc must be fully protected against corrosion; they should not rust when immersed in water, and no electrochemical corrosion should occur between different metals ； Secondly, the smooth surface reduces water resistance. 6.3 For the sanitary requirements of epoxy resin or paint used for anti-corrosion inside the valve body, test reports from relevant authoritative agencies shall be provided. The chemical and physical properties must also meet the relevant requirements.
7? Valve packaging and transportation? k5 7.1 Light blocking plates should be installed on both sides of the valve to secure it in place. ? 7.2 Valves of medium and small diameter should be tied with straw ropes and transported in containers. ? 7.3 Large-diameter valves are also packaged with a simple wooden frame for support, to prevent damage during transportation. 8? Manufacturer’s instructions for the valve? A valve is a type of equipment, and the manufacturer’s instructions should include the following relevant data: Valve specifications ； Model ； Work stress ； Manufacturing standards ； Valve body material ； Valve stem material ； Sealing material ； Valve stem packing material ； Material of valve stem bushing ； Internal and external anti-corrosion materials ； Operation start direction ； RPM ； Opening and closing torque under working pressure ； Name of the manufacturing factory ； Date of manufacture ； Factory serial number ； Weight ； Bore diameter, number of holes, and center hole spacing of the connecting flange ； Indicate the control dimensions of length, width, and height in a graphical manner ； Valve flow resistance coefficient ； Effective opening and closing cycles ； Data related to the factory testing of valves, as well as precautions for installation and maintenance.
One can rest from such reposting. It has misled many sea enthusiasts; I suggest that moderators delete such posts outright.
It makes no sense; it’s just filler. I suggest deleting it. Haichuan is a professional forum. Salespeople must learn how to select the right products, and this is a lengthy process.
It always seems that HaiChuan doesn’t have expertise in the water world field