How to distinguish soft sealing ball pneumatic valve and hard seal ball valve USES

let us to know about the hard seal ball pneumatic valve and soft seal on the structure mechanism of different pneumatic valve:
pneumatic valve is pneumatic metal hard seal ball seat and seal formed between metal ball, the machining accuracy and technology demand is higher, generally used in high temperature and high pressure condition and medium above, usually ° C or MPa above condition. Soft sealing ball pneumatic valve is metal and nonmetal pneumatic seat seal between the sphere, such as nylon or tetrafluoroethylene and PPL para polystyrene, manufacturing requirements are different.
the selection of soft and hard seal ball pneumatic valve basically see using process of the medium, temperature and pressure, usually containing solid particles or the medium of wear and tear or temperature is higher than had better choose pneumatic valve, hard seal ball diameter greater than the pneumatic valve pressure difference is bigger also consider open pneumatic valve torque size, large torque should be chosen when stationary pneumatic valve, hard seal ball seal level for both hard and soft seal can be achieved. The temperature is less than the general, medium, medium not containing particles can choose soft seal pneumatic valve ball.