Precautions for valve procurement

1 The model of the valve shall indicate the number requirements of the national standard If it is an enterprise standard, the relevant description of the model shall be indicated 2 The manufacturing standard of valve shall indicate the national standard number If it is an enterprise standard, the procurement contract shall be attached with the enterprise document 3 The working pressure of the valve shall be ≥ the working pressure of the pipeline On the premise of not affecting the price, the working pressure that the valve can bear shall be greater than the actual working pressure of the pipeline Performance test of valve: 1 When a certain specification of valve is manufactured in batch, the following performance tests shall be conducted by the entrusted organization: ① the opening and closing moment of the valve under the working pressure condition; ② the flow resistance coefficient of the valve under the pipeline water delivery condition 2 Before leaving the factory, the following tests shall be carried out for the valve: ① when the valve is open, the valve body shall bear twice the internal pressure of the valve; ② when the valve is closed, both sides shall bear 11 times the valve's internal pressure respectively, without leakage; however, for the metal sealed butterfly valve, the leakage value shall not be greater than the relevant requirements