Clear only when the valve procurement specifications, categories, the pressure to meet the requirements of the procurement practices, in the current economic environment where the market is imperfect. To valve manufacturers because of competition, both in their respective valve unified design concept, a variety of innovations, formed their own corporate standards and product personality. Therefore, in a more detailed valve procurement of the proposed technical requirements, coordination with the manufacturers to reach a consensus, as a valve procurement contracts annex is very necessary.

1, General Requirements

1.1 specifications and types of valves, piping design document should be consistent with the requirements. 1.2 valves should be specified based on the Model GB code requirements. If the enterprise standard, should be specified models of the note. 1.3 work pressure valve for the pressure of ¡Ý pipeline, without affecting the prices under the premise of the valve can withstand the pressure should be larger than the actual pipeline pressure; valve is closed under a state of any side should be able to bear 1.1 times the pressure valve leakage without value; valve open position, valve should be able to bear the pressure valve twice requirements. 1.4 valve manufacturing standards, a description based on the GB code, if corporate standards, procurement contracts should be attached business documents.

2, valves quality standard

2.1 Valve material should be based ductile iron, cast iron and indicate grades and the actual physical and chemical testing data. 2.2 stem material, to stainless steel stem (2 CR13), the large-diameter stainless steel valves should also be embedded packet stem. 2.3 nut material, using cast aluminum brass or cast aluminum bronze, and the hardness and intensity are greater than stem. 2.4 stem sleeve material, its hardness and strength shall be not more than stem, and immersion in water conditions and stem, the valve did not form electrochemical corrosion. 2.5 sealing surface of the material ¢Ù different types of valves, seals require different methods and materials; ¢Ú ordinary wedge gate valve, Tonghuan materials, fixed, grinding way should be; ¢Û soft sealing valve, the valve plate lining plastic materials and the physical and chemical health inspection data; ¢Ü Butterfly Valve should be marked on the sealing surface material and butterflies board sealing surface material; their physical and chemical detection data, particularly rubber health requirements, anti-aging properties, wear resistance ; usually Zhengqing rubber and EPDM rubber, recycled plastic-doped prohibited. ¢Ù filler valve 2.6-axis in the pipe network due to the valve is usually not frequent hoist to fill in the next few years do not, do not fill aging and long-term effects remain sealed; ¢Ú filler valve shaft should also bear in frequent hoist , the good sealing effect; ¢Û In view of the above request, the filler valve shaft to life did not change or not change for more than 10 years; ¢Ü filler For replacement of the valve should be designed to have the situation under pressure to replace measures.

3, Box Transmission

3.1 box inside and outside and anti-corrosion material requirements and consistent with the principles of Valve.

3.2 should be sealed box, box after assembly can withstand three meters of the water column situation immersion.

Box 3.3 on the hoist limiters, the adjustment nut should be Xiangbenna or in bins, but need special tools to work.

Drive 3.4 rational design of the structure, the gate valve can only lead rotating, it ran from top to bottom, transmission components occlusion moderate, no-load hoist when separation skid.

3.5 Transmission Box Office and the valve shaft seal leakage can not be connected with the overall, it should be reliable string of anti-leakage measures.

3.6 Xiangbenna no debris, grease gears bite site should be protected.

4, the operation of the valve body

4.1 operation of the valves open and close direction, clockwise should be closed.

4.2 As the networks in the valves, often artificial hoist, hoist it is not appropriate to a few too many, is also in the large-diameter valves to within 200-600.

4.3 In order to facilitate a person¡¯s hoist operation, the situation in the plumbing under pressure, the greatest moment to hoist 240 N-m.

4.4-valve hoist operation for the tenon, and the size standardization, and the ground-oriented, so that people can directly from the ground operation. Roulette with the valve does not apply to underground pipe network.

4.5 degree of valve gate valve hoist Set ¢Ù degree of calibration lines, should be cast in the gearbox back or change direction after the show was on the cover, will be facing the ground, brush on the scale of phosphor, to show eye-catching; ¢Ú instructions needle was better in the management of the material circumstances can be used stainless steel plate, or the plate for Painting, Paper Making Do not use aluminum; ¢Û instructions needle-eye-catching, fixed solid, if accurate adjustment after the hoist should be locked Rivet.

4.6 If the valves buried deeper, operation and the distance from the ground show was ¡Ý 1.5 m, there should be additional rod facilities, and stability firmly fixed, so that people observed from the ground and operate. In other words, the net gate valve operation, it is not appropriate to go down operations.

5, Valve Performance Testing

5.1 specifications quantities of a valve at the time of manufacture, should be entrusted authoritative institutions of the following properties: ¢Ù valve in the pressure situation. Hoist torque; ¢Ú pressure in the circumstances, to ensure that the valve is closed tight for Kai Closed number; ¢Û valves in the aqueduct under a state of flow resistance coefficient testing.

5.2 valves in the factory should be conducted the following tests: ¢Ù valve in the open position, the valve should be under the pressure valve twice the value of the pressure testing; ¢Ú valve closure circumstances, both sides were under 1.1 times The pressure of the valve, no leakage, but sealed metal butterfly valves, leakage value not greater than the requirements.

6, valves, the internal and external anti-corrosion

6.1 Valve (including Transmission box) inside and outside, first of all, should be throwing sand-derusting, non-toxic powder to electrostatic spray epoxy resin, the thickness of 0.3 mm or more. Electrostatic spray valve large non-toxic epoxy difficulties, we should Shuachu, similar to the drug-free epoxy spray paint.

6.2 Valve internal valve plate and all parts of a comprehensive anti-corrosion requirements, on the one hand immersion in the water will not rust, do not produce between two metal electrochemical corrosion; two aspects of a smooth surface to reduce water resistance.

6.3 valves in the anti-corrosion epoxy paint or health requirements, there should be a corresponding organs of authority of the report. Chemical properties should be in conformity with the relevant requirements.

7, the valve packing

7.1 valves should be located on both sides of light-blocking plate closure.

7.2, small-calibre valve should be tied to rope, and suitable container transport.

7.3 Summary large diameter valves also framework of solid wood packaging, so as to avoid collision damage during transport.

8, valve factory brochures

Valve equipment, the factory should be marked with the following statement relevant data: valve specifications; models; work pressure manufacturing standards; valve material; stem material, sealing material; valve shaft packing material; stem bushings material; inside and outside Anti-corrosion material; launches direction to; the pressure situation hoist torque; factory³§Ãû; pre-date factory code; weight connecting flange diameter, number of holes, the Centre Kongju; icon to indicate the overall approach length, width and height control size; valve flow resistance coefficient, the number of effective gate; valve factory of the relevant data and installation, maintenance and other matters needing attention.