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You are here: Home » What We Do »Ball Valves »Trunnion Ball Valve

A trunnion ball valve has mechanical anchoring of the ball at the top and the bottom, suitablf ro larger and higher pressure services. To ensure tight sealing at low pressure, high tensile springs force the seats against the ball while at higher pressure, the medium pressure pushes the upstream seat towards the ball.

EMERGENCY SEALS

For trunnion mounted ball valv size NPS 6 (ND 150) and above, it comes with provisions for sealant injection on both the stem and seat while for sizes NPS 5 (DN 125) and below on body cavity. In case of failed underperformed seals, a temporary emergency seal can be achieved by injecting sealants.

 

Seat Injection Valve Stem Injection Valve
Seat Injection Valve Stem Injection Valve

 

SINGLE PISTON EFFECT
 

The difference in area (D) times the line pressure creates a "piston effect" force which pushes the seat against the ball surface resulting in a tight effect seal.   When the pressure in the valve cavity reaches a level that the total force from cavity acting on the seat is larger than the total force from upstream line pressure, the seat will be pushed away from the ball to relief the valve cavity pressure.
Single Piston Effect Upstream Seat   Single Piston Effect Piston Upstream 2
 
DOUBLE PISTON EFFECT
The difference in area (D) times the line pressure creates a "piston effect" force which pushes the seat against the ball surface resulting in a tight seal.    The difference in area (D) times the cavity pressure creates a "piston effect" force which pushes the seat against the ball surface resulting in a tight seal.
Double Piston Effect Upstream Seat   Double Piston Effect Downstream Seat

ANTI-STATIC

Because the ball and stem in a ball valve are suspended on non-metalic parts, i.e. the seat seal and stem seal, there is a posibility a static charge may build up on the stem-ball, a mechanical (antistatic meal spring and ball) is introduced in the design to maintain the metal-to-metal contact between the rotating ball/stem and the valve body which will gournd any charges to the valve body.  

Anti-static Assembly

FIRE SAFE DESIGN

During a fire, non-metallic soft material will be burnt, subsequently seal leakage or external leakage may occur and cause the fire spread or contaminate the environment. FBV ball valves are fire tested in accordance with API 6FA or API 607, witnessed and certified by TUV SUD. If a valve is not covered according to the standards, they are designed to be fire safe.

Fire Safe



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