Whether the valve plays a sealing role is the basic requirement of the valve. In practical application, there are many types of seal, such as soft seal, hard seal, valve plate seal, valve body seal, surface seal, line seal and so on. No matter what kind of sealing form is used, it cannot affect the sealing effect. In the past, we have used a part of the valve plate sealed butterfly valve, theoretically speaking, the biggest advantage of this butterfly valve is that once the sealing apron failure, without disassembling the valve, can be replaced online. However, in the practical application of water supply enterprises, the advantages of this butterfly valve are difficult to reflect. Therefore, if the ring is replaced online, it is not only necessary to disassemble the pipe at both ends of the valve and empty the pipe. At the same time, the replacement of the rubber ring can not be sealed test, can not determine the replacement effect. Therefore, when choosing the valve, we must pay attention to the sealing form of the valve, and check the sealing effect of the valve combined with their actual application.
