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When the one-piece national standard flanged ball valve is used, we will encounter the following common problems, so it should be avoided in use.

     1. When the valve plate is in the normally open state, the fluid medium will have a positive impact on its sealing surface, which will directly affect the sealing performance.

     2. The stress structure conditions of the national standard integrated flange ball valve are not suitable for valves with a diameter below DN200. The reason for this is that the structure of the whole valve is relatively thick and the resistance to the flow rate is relatively large.