Trunnion ball valves are resuitable for use on various kinds of pipelines of Cl ass 1 50～Cla ss 2500 , PN1 6～PN1 60, JIS 10K～JIS 20K to cut off or turn on the pipeline medium, of which the operation types include worm gear, manual, pneumatic or electric actuators, being in general of flange connection, and butt welding ends connection as well.
Trunnion ball valve with the Bi-sealing design structure,i.e. seat sealing in front of the ball and seat sealing behind the ball
According to some special working conditions and customers' requirement, WEKE has provided the trunnion ball valve with the B i-sealing design structure , i.e. seat sealing in front of the ball and seat sealing behind the ball, thus the reliable sealing of the valve is ensured because the valve can perform normally even if one of the effective sealing designs becomes lost due to the abnormal condition. Regarding the seat in front of the ball, the piston effect formed by the are a difference between D1 and D2 ,plus the pre-tightened force of a spring would cause the seat in front of the ball by the pressure difference of the medium before and after the valve to touch the ball closely to form the tightness, of which the sealing force will become bigger as the pressure difference gets higher.Regarding the seat after the ball, the piston effect formed by the area difference between D2 and D3 ,plus the pretightened force of aspring would cause the seat behind the ball to touch the ball closely to form the tightness, of whic h the sealing force will become bigger as the pressure difference gets higher.
Blow-out proof stem
Blow-out proof structure is provited with for the stem, which is positioned by the up-end cap and screw, being guaranteed not to be blown-out by the medium even if at abnormal risen pressure in the cavity.
The ball of the trunnion ball valve gets close contact with each othe through the trunnion, adjusting cushion, and down-end cap, the passage of static electricity thus forms together with the valve , which may lead the static electricity caused by sparks generated by friction between the ball and seat during on and off performance to the ground to prevent the possible risk of fire or explosion.
Urgent grease injection device
According to customer s' requirement, the trunnion ball valves made by CHAODA c ompany are provided with devices for urgent grease injection, which are on both the stem and seat for the trunnion ball valves of DN >150mm (NPS), and in the body cavity for the valve of DN < 125mm. When the O ring of stem or the body seat ring is damaged due to accident, the medium leakage between body and stem can be prevented by injecting the sealing grease through the device.
Double-block and bleed functions
In general, CHAODA's trunnion ball valve features the front ball sealing design structure. Each seat of the ball valve can separately cut off the medium at both inlet and outlet of the valve to realize double-block functions. When the ball valve is closed, body cavity and two of the body ends can be blocked with each other even if both the inlet and outlet are under pressure, when the medium left in the body cavity might be bled through the relief valve.
Fire safe design
With the valve heated in a fire application, the non-metal material parts such as seat sealing ring of PTFE, O ring for the stem, and sealing gasket for body and bonnet, might be damaged due to high temperature. CHAODA's special design of auxiliary metal to metal or the graphite seal is provited fo rthe trunnion ball valve to effectively prevent both internal and external leakage of the valve. As required by customers, CHAODA's fire safe design for the trunnion ball valve meets the requirement of API 607, API 6Fa, BS 6755 and JB/T 6899.
Self-relief in the body cavity
As the liquid medium left in the body cavity gasifies due to increased temperature, the pressure in the body cavity becomes abnormally higher, when the medium itself in the cavity would propel the seat and self-relieves the pressure to ensure the safety of valve.
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