SBV Forged Steel Trunnion Mounted Ball Valves are used mainly in Oil,Gas Transmission and Distribution Pipeline,Petroleum ,Chemistry, Chemical Fiber,Metallurgy,Paper Pulp etc.The forging material can ensure sufficient rigidity and strength under maximum rated operation pressure without inherent flaw of cast. The Forged Steel Body assures uniform fine grain structure and toughness free from inevitable casting defects such as porosity, abscess, crackle, gas hole. 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
SBV Forged 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’s no limitation of flow direction during installation. (PIC.1)
2. Trunnion-Mounted Ball
The ball is fixed 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 Design (Standard)
(Single Piston Effect Seat Design)
It is the standard seat design for SBV 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 case of 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 607-4th, API 6FA and BS 6755 Part 2.(PIC.5)
b) External Leakage Prevention
A combination of O-ring and SS304/SS316+graphite spiral wound gasket on body/caps connection, body/gland connection, and stem/gland joint, can prevent the external leakage. When O-rings are damaged after a fire, body gasket, gland gasket, and stem packing can reach temporary sealing function and prevents external fluid leakage. It is in compliance with API 607-4th, API 6FA and BS 6755 Part 2. (PIC.6)
9. Anti-Static Design
During turning of the stem to opening and closing the valves, the static electricity is easily caused by sparks generated by the friction among ball and stem, stem and body. Antistatic devices which is assembled by a static-conduction spring & a grounding plunger will assure the electrical conductance continuity, so, the static electricity is conducted to the ground and prevent the possible risk of fire or explosion. So, system safety is secured. (PIC.3)
10. Blow-Out Proof Stem Design
For the purpose of preventing the stem from flying off resulting in abnormal rising of the inner pressure of valve, the stem with integral T-type shoulder supported by gland, can be guaranteed not to be blow-out by the medium even if at abnormal rising pressure in the cavity. (PIC.3)
11. Emergency Sealant Injection System
For 6" and larger SBV Forged Steel Trunnion Mounted Ball Valves (Small size on request, if design is allowed), in case of fire or other accidents, the seat or stem O-rings are damaged and the valve got leakage, the special sealing grease may be injected through a sealant injection fittings that are located on the adapter and the gland to obtain emergent and temporary sealing function and prevent fluid leakage.(PIC.4)
12. Stem Sealing System
Two O-ring and one graphite Packing/gasket, retained by the gland bushing, ensure the stem seal. The Graphite Packing/Gasket can be replaced while the valve is under pressure and with the ball in any position. The stem seals can be replaced with the valve under pressure, when the ball is in the fully open or fully closed position, and the body cavity overpressure has been released to the atmosphere.
13. Body Sealing System
The double sealing action of O-rings and SS304/SS316+graphite spiral wound gasekts between body and caps, it can ensure body sealing “o” leakage. O-Ring can be replaced by lip-seal ring and /or graphite gaskets for special services .
14. Stem Extension
For the underground installed valve, the stem can be extended and for the convenience of operation, the Sealant Injection System and Drainage valve can be extended to the top of valve. The stem extension length shall be as per customer’s requirements.
15. Low Operation Torques
The seat and stem using PTFE+304 bearings with small friction and self-lubrication to reduce the valve operation torques. The valve can be easily operated for long period even without sealing lubrication grease.
16. Locking Device (on request)
Pad Locks can be used to lock the manual valve when it is fully open or closed, so as to prevent non-working personnel from operating the Lever or Gear Boxes which may result in disoperation of valve. It can also avoid opening or closing of valve resulting from the shock from pipelines or unpredictable factors that may cause an accident. For working pipelines such as combustible and explosive oil, gas and chemical medium, or for field piping site, the locking mechanism is especially useful.
17. Various Operation Types
The Top Working Pad of this valve is designed according to ISO 5211 (if design is allowed),which is convenient for connection and change its operation types. The common operation types are manual (Lever/Gear Box), electrical, pneumatic and pneumatic/hydraulic.
The use of Lever/Wrench is limited to valves equal or smaller than:
*4"-Class 150 *4"-Class 300 *3"-Class 900 *2"-Class 1500 *1"-Class 2500
18. Low Emission Packing Design (Environmental Protection)
With more and more concern for environment protection in the whole world, low emission valve will be widely used. Low emission valve can prevent poisonous, flammable, explosive medium from leakage to pollute the atmosphere, and also low emission valve can minimum fugitive emission of VOC to help solve the problem of "Global Warming"
Because of frequent opening and closing of the valves, normal graphite granule can be drawn by the stem, which will cause leakage. The Low Emissions valves designed by SBV use special low emissions packing to ensure the seal of stem. The cone packing is made of expanding graphite in die-formed rings and has features of heat resistance, less stress relaxation and low creep. With this special structure, it allows for a low-friction on rotary & rising stem valve, therefore providing the stabilized sealing performance for long cycle life.