Fixed pneumatic ball valve with pneumatic valve ball floating seal principle

fixed pneumatic ball valve is mainly used in high pressure, large diameter pneumatic ball valve. Depending on the installation of the pneumatic valve seat seal, fixed pneumatic ball valve has a sphere before sealing pneumatic seat and ball after seal pneumatic seat two structures.
sphere before sealing pneumatic seat sealing principle: and pneumatic valve stem as a whole sphere can be free in the sliding bearing up and down or rolling bearing rotation, pneumatic valve seat sealing ring is installed inside the sleeve of the activity, the sleeve in the pneumatic valve ring seal is used. Pneumatic seat sealing ring consists of a set of installation in the sleeve spring pressure in advance. Import the pneumatic valve seat, the pneumatic ball valve is closed, by acting on the inlet diameter d and cooperate with pneumatic valve sleeve diameter d. Defined by the circumference of the ring on the surface of the medium pressure pneumatic seat pressure to a sphere, which imported seal effect, can't afford to the outlet of pneumatic valve seat sealing function. The role of reverse pressure, pneumatic seat will be changing.
the floating ball of pneumatic valve pneumatic valve body with two pneumatic seat sealing, clamping a sphere between them, there is hole on a sphere, the diameter of the hole is equal to the inner diameter of the pipeline, said pneumatic full bore ball valve; The diameter of the hole is slightly smaller than the inner diameter of the pipe, said reducing pneumatic ball valve. Sphere with the aid of pneumatic valve rod can freely rotating in the pneumatic seat sealing. In open, aim the ball hole and pipe diameter, to ensure the working medium of least resistance. When the pneumatic valve rod rotation/circle, the ball hole perpendicular to the channel of the pneumatic valve, depend on two pneumatic seat sealing of pre-tightening force and the medium pressure ball tightly pressed on the outlet pneumatic seat sealing, to ensure that the pneumatic valve completely sealed. This pneumatic valve ball belongs to single seal.
the floating ball pneumatic ball valve should also be considered pneumatic valve seat materials can withstand the load of ball, because spheres besides own self-respect also all work under medium load and to the pneumatic valve seat. In addition, consider float pneumatic valve in the operation of the large diameter need greater force.
in order to ensure that the floating ball pneumatic ball valve sealing and reliability, at work on a sphere and pneumatic seat contact surface, should have the sealing pressure is high enough, but shall not exceed the allowable pressure of the pneumatic valve seat materials. Pneumatic valve seat in the groove with should be tight, otherwise even if pneumatic seat to the sphere of the sealing is very good, the medium will be along the groove end leakage. Spheres should have the correct geometry and low surface roughness values. Usually in h or h precision manufacturing ball, the surface roughness value is not more than R. 。 , in order to improve the surface hardness and wear resistance of sphere, the sphere surface hardening treatment may be performed. Pneumatic seat available plastic seal, and shall ensure that fit closely, shall not damage the sealing face of the sphere. At the same time, the material should have sufficient strength, so that can seal under high pressure. Ptfe is manufacturing pneumatic seat of one of the most commonly used materials.