STANDARD COMPLIANCE

AVC Cast Steel Trunnion Mounted Ball Valves are used mainly in Oil, Gas Transmission and Distribution Pipeline, Petroleum ,Chemistry, Chemical Fiber, Metallurgy, Paper Pulp etc..Enough wall thickness of separate Body and Adapters and high strength tie bolts are convenient for valve maintenance and sufficient to bear the stress of pipe. The internal parts of valve are carefully designed and selected to ensure reliability under all kinds of work condition.

1. Upstream Sealing Bi-Directional

AVC Cast Steel Trunnion Mounted Ball Valves are equipped with two self energized seats. The upstream sealing of the valve is fulfilled by the advanced spring pre-tighting seat package which has a feature of self-tightness. The Bi-Directional valve has two seats that can be sealed on two directions, so there is no limitation of flow direction during installation. (PIC.1)
2. Trunnion-Mounted Ball

The ball is fized and the seat rings are floating, it is free to move along the valve axis. Side load generated by the pressure acting on the ball is absorbed by bearings.
At low pressure, the seat sealing action is achieved by the thrust of the spring action on the seat rings.
As the pressure increases, the fluid pressure pushes the seat rings against the ball.

3. Floating Seat Rings

Independent floating seat rings assure the bi-directional tightness of the valve. The seat are carefully designed to minimize the operation torques.

4. Independent Ball and Stem (For 2" and larger)
For 2" and larger size, the ball and stem are independent to minimize the effect of the side thrust occurred by the pressure acting on the ball. For below 2”, the ball and stem is integrated.

5. Self Relieving Seat (Single Piston Effect Seat Design)-(It is our Standard Design)

It is the standard seat design for ZXV Forged Trunnion Mounted Ball Valves. The fluid pressure, both upstream and downstream creates a resultant thrust which will push the seat rings against the ball. Fluid pressure acting in the body cavity creates a resultant thrust that will push the seat rings away from the ball. So, any overpressure in the body cavity can be automatically relieved when the valve is in the fully open or fully closed position, and then the seat returns to the ball under spring action. (PIC.1)

6. Double Piston Effect Seat Design (On request)
Fluid pressure, both upstream and downstream, as well as in the body cavity creates a resultant thrust that will pushes the seat rings towards the ball, this design will be adopted as per customer’s request, the valves with double piston effect seat rings may require a relief valve to reduce the build-up of overpressure in the body cavity, that means this type valve cannot automatically relieve the body cavity.

7. Double Block & Bleed (DBB)

When the ball is in the fully closed position, each seat of the ball valve can cut off the medium independently on the upstream and downstream side to realized double-block functions. The body cavity is isolated from each side of the valve, the body cavity pressure could be released through the vent valve and drainage valves. (PIC.2)

8. Fire Safe Design

a) Internal Leakage Prevention

When seat insert, O-ring and spacer are damaged in a fire, the line pressure and the seat preloaded spring push the seat metal lip into the ball sureface to cut off the line fluid and prevent the internal leakage to reach fire-safe purpose. It is in compliance with API 607-4