Ball valve door soft seal and hard seal use difference

Ball valve door there is a difference between hard and soft sealing use, mainly on the structure, the valve manufacturing standards is different to the door. Structure on the mechanism of ball valve door is between metal and metal hard seal seal, seal sphere and valve seat are metals. The machining accuracy and process is difficult, generally used in high pressure, often more than 35 mpa. Soft seal is sealed between the metal and nonmetal, such as nylon tetrafluoroethylene, manufacturing standards are the same. Sealing material on the hard and soft sealing is the valve seat sealing materials, precision machining, hard seal with the valve seat material guarantee and the valve core ( A sphere) The matching accuracy, generally speaking, there are stainless steel and copper. Soft seal is mounted on the valve seat sealing material for non-metallic materials, because of the soft sealing material has certain elasticity, therefore hard seal will be relatively low demands on machining accuracy. Because of many chemical manufacturing process, mechanical industry working environment is more complex, many of them are high temperature and high pressure, the medium of frictional resistance is big, strong corrosion, now technological progress, all kinds of materials used is better, can keep up with all the aspects of processing, make hard seal ball valve door widely promoted. Principle and soft hard sealing ball valve door seal is the same, just because is sealed between the metal, to consider the relationship between the hardness of metal, as well as the working condition, what medium, etc. Are generally required to do hardening treatment, between the ball and valve seat to grinding to the seal. Hard seal ball valve door production cycle is long, processing is more complex, hard seal ball valve door is not easy to do. Conditions of use on soft seal generally seal can achieve very high, while hard seal according to the requirements can be high to low; Soft seal need to fire prevention, because at high temperatures, soft sealing material will leak, and hard seal is not the problem; Hard seal generally can do high pressure, soft seal is not; Soft seal due to the problem of flow medium, some occasions is can't use, Some corrosive medium, for example) ; The last hard seal ball valve door generally more expensive than soft sealing. In manufacturing, both difference is not big, mainly is the difference between the valve seat, non-metallic, soft seal is is metal hard seal. Soft and hard seal ball valve door on equipment selection choose mainly based on the technology of medium, temperature and pressure, the general medium containing solid particles or with wear or temperature higher than 200 degrees had better choose hard seal, diameter larger than 50 differential pressure valve door also considered open valve door torque size, large torque should be chosen when hard seal fixed ball valve door, both hard and soft seal their level of sealing can reach level 6.