The difference between elastic soft-sealing gate valve and hard seal gate valves
The difference between elastic soft-sealing gate valve and hard seal gate valves:
structural mechanism: hard sealing between metal and metal sealing, sealing ball and 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.
Two, sealing material: elastic soft-sealing gate valve and hard seal gate valves are for the seat of the sealing material,
hard seal is to use the seat material precision machining, assurance and the matching of the valve core (sphere) accuracy, generally have stainless steel and copper.
Soft seal is set in the 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.
Three, because a lot of 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,
technological progress, now all kinds of materials used is better, can keep up with all the aspects of processing, make hard seal ball valve has been widely promoted.
Actually hard seal principle and soft sealing gate valve 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 seat to grinding to the seal.Hard seal gate valve production cycle is long, processing is more complex, hard seal ball valve is not easy to do.
Four, on the conditions of use 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 places are can't use some corrosive medium (such as);
The last hard seal generally more expensive than soft sealing valve.
In manufacturing, both difference is not big, is the seat of the main difference, non-metallic, soft seal is is metal hard seal.MianRuan on equipment selection and hard seal gate valve is chosen mainly according to the process 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 greater than 50 valve pressure difference is bigger also considered open valve torque size,
large torque should choose fixed hard seal gate valves, both hard and soft seal their level of seal can reach level 6.
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