The ball valve structure is mainly divided into two types: fixed type and floating type. The common small-diameter ball valves are all floating structures. Under the action of pressure and fluid, the valve seat where the ball flows to the medium is sealed and compressed to achieve the sealing effect. The greater the pressure, the better the sealing. it is good. The structure of the fixed ball valve is simply that there are shaft pins at the top and bottom of the center of the ball valve. In large-diameter occasions, a fixed ball valve must be used to avoid the weight of the ball to crush the seal. The eccentric ball valve and the V-shaped ball valve are all fixed. ball valve.
There are two main types of ball valve seals: soft seal and hard seal. Soft-seal ball valve means that one side of the seal is made of metal material, and the other side is of elastic non-metallic material, which is called "soft seal". This kind of seal has good sealing performance, but it is not resistant to high temperature, easy to wear, and has poor mechanical properties. Soft-sealed seat ball valve is made of non-metallic materials with certain strength, hardness and temperature resistance. It has good sealing performance and can achieve zero leakage, but its service life and adaptability to temperature are relatively poor. The soft seal cannot meet the process requirements for some corrosive materials, and the hard seal can be solved. These two seals can complement each other. In terms of sealing, the soft seal is relatively good, but now the sealing of the hard seal can also meet the corresponding requirements. The advantage of soft seal is good sealing performance, but the disadvantage is easy aging, wear and short service life. The hard seal has a long service life, but the sealing performance is relatively poorer than that of the soft seal.
