The difference between soft seal gate valve and hard seal gate valve

The difference between soft seal gate valves and hard seal gate valves mainly lies in the following aspects:

1、 In terms of structural mechanism, a hard seal is a seal between metals, where the sealing ball and valve seat are both made of metal. The machining accuracy and process are relatively difficult, and are generally used on high voltage. Soft seal is a seal between metal and non-metal, such as nylon tetrafluoroethylene, manufactured to the same standard

2、 Soft and hard sealing refers to the sealing material of the valve seat. Hard sealing is made of finely processed valve seat material to protect the fitting accuracy with the valve core (ball), usually made of stainless steel and copper

The sealing material embedded on the valve seat of the soft seal gate valve is non-metallic. Due to the elasticity of the soft sealing material, the machining accuracy requirements are relatively low compared to hard sealing

3、 In terms of manufacturing technology, due to the complex working environment of many chemical and mechanical industries, many of which are high temperature and pressure, with high frictional resistance and strong corrosiveness of the medium. With the advancement of technology, the use of various materials is better, and processing and other aspects can keep up, making hard sealed ball valves widely promoted

In fact, the principle of hard sealed ball valves is the same as that of soft sealed valves, except that due to the sealing between metals, the hardness relationship between metals, as well as the working conditions and the medium used, need to be considered. Generally, hardening treatment is required, and the ball and valve seat need to be continuously ground to achieve sealing. Hard sealed ball valves have a long production cycle and complex processing, making them difficult to manufacture

4、 In terms of usage conditions, soft seals can generally achieve high sealing, while hard seals can vary in height according to requirements; Soft seals require fire prevention (based on actual reports), as the material of soft seals may leak at high temperatures, while hard seals do not have this problem; Hard seals can generally achieve high pressure, while soft seals cannot; Soft seals cannot be used in some situations due to the problem of the flowing medium (such as some corrosive media); Afterwards, hard sealed ball valves are generally more expensive than soft sealed ones

As for manufacturing, there is not much difference between the two, mainly the difference in valve seat. Soft seals are non-metallic, while hard seals are metallic

5、 In terms of equipment selection, the selection of soft and hard sealed ball valves is mainly based on the process medium, temperature, and pressure. Generally, if the medium contains solid particles or has wear or temperature above 200 degrees, it is better to choose a hard seal. If the valve diameter is greater than 50 and the pressure difference is large, the opening torque of the valve should also be considered. When the torque is large, a fixed hard sealed ball valve should be selected. Regardless of whether it is a soft or hard seal, its sealing level can reach level 6