Flat gate valve seal material difference

First, in the selection of equipment above

Soft and hard-sealed gate valves are mainly based on process media, temperature and pressure, general media containing solid particles or having a wear or a temperature higher than 200 degrees is the best choice for hard sealing, caliber greater than 50 valve differential pressure is also considered to open the valve moment size When the torque is large, the fixed hard-sealed gate valve should be used. The sealing grade of the soft and hard seal can reach 6 levels.

Second, the use of conditions

Soft seals can generally achieve high seals, while hard seals can be as high or low as required; soft seals require fire protection, because at high temperatures, soft seal material will leak, and hard seal does not have this problem; hard seal Generally speaking, high pressures can be done, but soft seals are not. Soft seals cannot be used in some applications (such as some corrosive media) due to the problem of flowing media. Finally, hard seal valves are generally more expensive than soft seals. As far as manufacturing is concerned, the difference between the two is not significant. The main difference is the valve seat. The soft seal is non-metal, and the hard seal is metal.

Third, the manufacturing process

Due to many chemical and mechanical industries, the working environment is more complicated, and many of them are high temperature and high pressure. The frictional resistance of the medium is large and corrosive. Now that the technology has been improved, the use of various materials is better, and processing and other aspects can be followed. On the hard-sealed ball valve has been widely promoted.

In fact, the principle of the hard-sealed gate valve is the same as that of the soft seal. However, due to the fact that it is a seal between metals, the relationship between the hardness of the metals, the operating conditions, and the medium to be taken should be taken into consideration. Hardening treatment is generally required, and the balls and the seat must be constantly ground to achieve sealing. Hard-sealed gate valves have a long production cycle and are complicated to process. Hard-seal ball valves are not easy to do.

Fourth, on the sealing material

The flexible soft seal gate valve and the hard seal gate valve are the seal materials for the valve seat. The hard seal is precisely machined with the seat material to ensure the accuracy of the valve core (sphere). Stainless steel and copper are generally used. Soft sealing means that the sealing material embedded in the valve seat is a non-metallic material. Because the soft sealing material has a certain degree of elasticity, a relatively hard sealing of the processing accuracy will be low.