WM383 Trunnion ball valve

●Application

       Trunnion ball valves are suitable for use on various kinds of pipelines of Class 150-Class 2500, PN16~PN160, 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.

Design features of trunnion ball valve

●Urgent grease injection device

According to customers requirement the trunnion ball valve made by WILLIAMSON company are provided with devices for urgent grease injection, which are on both the stem and seat for the trunnion ball valves of DN>150mm(NPS6), 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, WILLIAMSONs 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 close, 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. WILLIAMSONs special design of auxiliary metal to metal or the graphite seal is provided for the trunnion ball valve to effectively prevent both internal and external leakage of the valve. As required by customers, WILLIAMSONs fire safe design for the trunnion ball valve meets the requirement API 607, API 6Fa, BS6755 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 o ensure the safety of valve.
 

●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, WILLIAMSON has provided the trunnion ball valve with the Bi-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 area 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 Pretigh-tened force of a spring would cause the seat behind the ball to touch the ball closely to form the tightness, of which 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.

●Anti-static design

     The ball of the trunnion ball valve gets close contact with each other 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.

●Mounting pad provided

    WILLIAMSON company has provided for trunnion ball valve with a mounting pad for fixing the actuators, such as worm gear, pneumatic, electric, hydraulic and pneumatic &hydraulic acturtors.
 

●Forged steel trunnion ball valve

     WILLIAMSON company manufactures in general trunnion ball valve of casted steel valve body. However, if required by customers, forged steel valve body is also available, of  which the flange dimensions and face to face dimensions are the same as that of cast steel trunnion ball valve.

●Ball valve with reduced bore

     Except for full bore ball valves, WILLIAMSON  company manufactures also the ball valve with reduced bore to meet different requirement of customers, which not only lowers the cost and  pricing, but also satisfies the special requirement  of customers.

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