General requirements

1. The specifications and categories of pneumatic valves should meet the requirements of piping design documents.

2. The type of pneumatic valve should be marked according to the GB number requirements. If the enterprise standard does well, it should specify the relevant description of the model.

3. Pneumatic valve working pressure requires more than pipeline working pressure. Without affecting the price, the valve should be able to withstand more than the actual pressure of the pipeline. Pneumatic valve closed on any side of the valve that should be able to withstand 1.1 times the value of valve working pressure without leakage. In valve opening conditions, the valve body should be able to withstand twice the valve working pressure equirement.

4. Manufacturing standards for pneumatic valves should specify the number of national standards on which they are based. If they are enterprise standards, enterprise documents should be attached to the procurement contract. Pneumatic valves are divided into three categories: national standard, American Standard and Japanese standard.

5. The complete description of the pneumatic valve includes its size, material, connection mode, and action mode (in which the action mode is divided into 1: double-acting, 2: single-acting).

Performance requirement

1. When a certain specification of a valve is manufactured in batches, the authority should be entrusted with the performance tests, including valve opening and closing moment under the condition of working pressure, under the condition of working pressure, the number of continuous opening and closing can be ensured and the flow resistance coefficient of valves under the condition of water conveyance.

2. Valves should be tested before leaving the factory. For example, when the valve is opened, the valve body should bear the internal pressure detection of two times the valve working pressure. When the valve is closed, the two sides are subjected to 1.1 times the valve working pressure value and no leakage, but the metal seal butterfly valve and leakage value are not greater than the relevant requirements.