Pneumatic check valve General requirements:

1, the production of pneumatic valve specifications and categories, should conform to the requirements of piping design documents.

2, the type of pneumatic valve should be indicated according to the national standard number requirements. If the enterprise standard, should indicate the model of the relevant instructions.

3, pneumatic valve work pressure, requirements ≥ pipe work pressure, without affecting the price of the premise, the valve can withstand pressure should be greater than the actual pressure of the pipe, pneumatic valve closed on any side should be able to withstand 1.1 times times the valve pressure value without leakage, valve opening conditions, valve body should be able to withstand twice times the requirements of valve pressure.

4, Pneumatic valve manufacturing standards, should indicate the basis of the national standard number, if the enterprise standards, procurement contracts should be accompanied by enterprise documents.

Pneumatic Check valve material:

1, the valve body material, should take the ductile iron mainly, and indicated the grade and the actual physical chemistry examination data of the cast iron.

2, valve stem material, and strive to stainless steel stem (2CR13), large diameter valves should also be stainless steel inlay the stem.

3, nut material, the use of cast aluminum brass or cast aluminum bronze, and hardness and strength are greater than the stem.

4, valve stem bushing material, its hardness and strength should not be greater than the stem, and in the water immersion condition and valve stem, valve body does not form electrochemical corrosion.

5, sealing surface material:

① Pneumatic Valve categories, sealing methods and material requirements are different;

② Ordinary wedge-type gate valve, copper ring material, fixed way, grinding method should be explained;

③ Soft sealed gate valve, valve plate lining material physical and chemical and sanitary testing data;

The ④ butterfly valve should be marked with the sealing surface material on the valve body and the sealing surface material on the butterfly board; their physical and chemical testing data, especially the hygienic requirements of rubber, anti-aging properties, wear resistance, no use of recycled plastic.

6, Valve shaft FILLER:

① as a result of the pneumatic valve in the pipe network, usually open and close is not frequent, the requirements of fillers in a few years of inactivity, fillers are not aging, long-term to maintain the sealing effect;

② Valve shaft Fillers should also withstand frequent opening and closing, sealing effect of good;

③ in view of the above requirements, valve shaft filler strive for lifelong not to change or more than 10 years not to replace;

If the ④ filler needs to be replaced, the pneumatic valve design should consider the replacement measures under the condition of hydraulic pressure.

Performance testing of pneumatic check valve

1, Valve A specification batch manufacture, should entrust authoritative authority to carry on the following performance inspection:

The opening and closing moment of ① valve under the condition of working pressure;

② in the condition of working pressure, can ensure that the valve closed close to the number of consecutive headstock;

Measurement of the flow resistance coefficient of the ③ valve under the condition of pipeline water conveyance.

2, the valve should be carried out before the factory inspection:

① valve in the open state, the valve body should withstand the valve pressure value twice times the internal pressure detection;

② Valve closed, both sides of the valve under 1.1 times times the pressure value, no leakage, but the metal sealed butterfly valve, leakage value is not more than the relevant requirements.

internal and external anticorrosion of pneumatic check valve

1, valve body (including variable-speed transmission box) inside and outside, the first should be shot clear sand derusting, and strive to electrostatic spraying powdery non-toxic epoxy resin, thickness up to 0.3mm or more. Extra large valve Electrostatic spraying non-toxic epoxy resin has difficulties, should also be brushed, spraying similar non-toxic epoxy paint.

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

3, the valve body anti-corrosion epoxy resin or paint hygiene requirements, should be the corresponding authority of the inspection report. Chemical and physical properties should also meet the relevant requirements.

Pneumatic check valve packing and transportation

1, the valve should be set on both sides of the light block plate solid seal.

2, medium and small-caliber valves should be rope strapping, and container transportation is advisable.

3, Large diameter valve also has a simple wooden frame solid packaging, so as to avoid damage during transportation.

Pneumatic check valve is the use of compressed air actuated valves. Pneumatic valve procurement only clear specifications, categories, work pressure to meet the procurement requirements of the gas method, in the current market economy environment is imperfect. Because the pneumatic valve manufacturers in order to compete for products, each of the pneumatic valve in the concept of a unified meter, to carry out different innovation, the formation of their own enterprise standards and product personality. Therefore, in the pneumatic valve procurement more detailed technical requirements, and manufacturers to achieve consensus, as a pneumatic valve procurement contract attachment is very necessary. This type of valve in the pipeline should generally be installed horizontally.