2. 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.

3, valve manufacturing standard, should state the national standard number according to, if the enterprise standard, the procurement contract should be attached to the enterprise documents.

 

Valve sealing performance refers to the valve sealing parts to prevent the ability of media leakage, it is an important valve * technical performance index. The sealing part of the valve has three places: the contact place between the opening and closing parts and the sealing surface of the valve seat; Fitting of packing with stem and packing box; Where valve body meets bonnet. One of the previous leaks is called an internal leak, which is often referred to as a loose closure, which will affect the valve's ability to cut off the medium. For the cut-off valve class, internal leakage is not allowed. The last two leaks are called external leaks, that is, media leakage from the valve to the valve. Leakage will cause material loss, pollution of the environment, serious will also cause accidents. For flammable, explosive, toxic or radioactive medium, leakage is not allowed, so the valve ** has a reliable sealing performance.