Trunnion Mounted Ball Valve

Trunnion mounted ball valves are generally manufactured with the features of double block and bleed (DBB), cavity relief, bi-directional, fire safe and secondary metal to metal seated etc.


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Key Specifications / Features

Trunnion mounted ball valves are generally manufactured with the features of double block and bleed (DBB), cavity relief, bi-directional, fire safe and secondary metal to metal seated etc.

Trunnion mounted ball valves are made of carbon steel, stainless steel and low temperature carbon steel and duplex steel for oil & gas, and power generation industries.

As one of the reliable trunnion mounted ball valve manufacturers in China, Relia supplies Trunnion mounted ball valves wchich are designed and manufactured as API 6D, API 608 or other international Standard as client request. All the Trunnion mounted ball valves are 100% under hydrualic and penumatic test before leave the factory.

Standard Specifications

Design and Manufacture API 6D
Wall Thickness API 6D
Face-to-Face Dimension API 6D
Flange End Dimension ANSI/ASME B16.5 (1” to 24”)
ANSI/ASME B16.47 (26” & up)
Butt-Weld End Dimension ANSI/ASME B16.25
Inspection & Testing API 6D/API 598
Fire Safe Design API 607/BS 6755
Material Nace MR 0175

Product Range

Body Construction Bolted Body/Welded Body
Body Material Carbon Steel, Low Temperature Carbon Steel, Stainless Steel, Duplex Steel
Seat Soft Seat: PTFE, RPTFE, Nylon, PEEK, PPL, Delrin, Devlon, PCTFE, PTFE Glass Filled, PTFE Carbon Filled
Metal Seated: Stellite, Tunsten Carbide, Chrome Carbide
Size Range 1-1/2”-56” (DN40-DN1400)
Class Rating ANSI Class 150-2500 (PN20-PN420)
End Connection Butt Welding, Flanged, Hub
Operator Lever, Worm Gear, Electric, Penumatic, Hydraulic, Oil Over Gas
Industry Servered Oil, Gas, Power Gerneration

Design Features

Fire Safe

Fire safe design is as per API 607/API F6A, to ensure the valve leakage test meet the standard request even after fire test.

Double block and bleed (DBB)

Double Block: When the ball is in the closed position, each seat seals off the process medium independently at the same time between the up/down stream.

Bleed: When the ball is in the closed position, any trapped liquid that might vaporize and expand can then do so at no greater than upstream line pressure. In a trunnion mounted ball valve, if the cavity pressure gets much above the line pressure, the spring-loaded seats should relieve the pressure before the valve is damaged.

Typical application: Pipeline ball valves in liquid services, to prevent pressure buildup in body cavity due to change in temperatures.

Self Cavity Relief (Self Relieving Seat)

Trunnion mounted ball valves constrain the ball by bearings. It is only allowed to rotate, but the seat can move. It also traps the media in the cavity when the operator closes the valve. It isolates the pipeline and the body cavity in the open and closed position. Thus, the pressure caught in the body cavity might be different from that in the line. The pressure increases in the cavity when heated. It pushes the ball seat of the downstream side away from the ball by rising pressure against the spring load. When this happens, the pressure gets released.

Secondary Metal to Metal Seat Design

Standard seat design is primary soft seal, and secondary metal to metal seal. Seat insert is designed as pressed-in type which is easy for maintenance. Optional design with primary metal to metal seal and secondary soft seal seat design is also available upon request.

Double Piston Effect Seats-(DPE*DPE) Optional

DPE seats are designed to be pushed against the ball in both cases, whether pressure comes from body cavity or from upstream/ downstream side. Ball valve with DPE seats cannot perform cavity relief. For such reason -in liquid services- the use of a relief valve is recommended.

Typical application: Whenever it is necessary to create an additional safe barrier between the upstream and the downstream sides. Recommended in welded body valves, where seats maintenance is notforeseen.

Combined SPE-DPE (Optional)

Upstream SPE seat ensures self relieving capability, while downstream DPE seat grants the double barrier in case of upstream seat damage. This configuration involves a preferred direction of installation with SPE seat facing upstream. With SPE-DPE configurations, cavity relief always takes place through SPE seat.

Typical application: Riser valves, pig launchers/receivers. DPE seat gives double isolation to the pig trap, allowing automaticrelief of body cavity at the same time in case of pressure build up.

Emergency Sealant Injection System

Each ball valve of size 6” and larger (or smaller size on request), is equipped with sealant injection located at stem and seats area. The injection is integrated with check valve to provide backup sealing, also a check valve is equipped at front of seat sealant injection to avoid blowing out in case wrong operation. When the soft sealing materials (seat inserts and o-rings) are damaged and leakage happened by fire or other accident, the sealant can be injected through the injection fittings.

Blow-out Proof Stem

The stem is made separately from the ball with integral T-type round shoulder, retained by gland.

Anti-static Device

Spring plus graphite type anti-static device are applied between the ball, stem, gland flange and body, to keep the electrical continuity between all the metallic components, and ensure the resistance lower than the most severe service requirement.

Typical Drawings

Material Specifications

No. Name of Part A105/ENP A105/F316 Nace LF2/F316 F316/F316
1 Nut ASTM A194 2H ASTM A194 2HM ASTM A194 7 ASTM A193 B8
2 Bolt ASTM A193 B7 ASTM A193 B7M ASTM A320 L7 ASTM A182 F316
3 Bonnet ASTM A105 ASTM A105 ASTM A320 LF2 ASTM A182 F316
4 Gasket SS304+Graphite SS316+Graphite SS316+Graphite SS316+Graphite
5 O-Ring Viton AED Viton AED Vion AED Vion AED
6 O-Ring Viton AED Viton AED Vion AED Vion AED
7 Graphite SS304+Graphite SS316+Graphite SS316+Graphite SS316+Graphite
8 Spring Inconel X-750 Inconel X-750 Inconel X-750 Inconel X-750
9 Seat Ring ASTM A105 ASTM A182 F316 ASTM A182 F316 ASTM A182 F316
10 Pin Carbon Steel Stainless Steel Stainless Steel Stainless Steel
11 Trunnion ASTM A105 ASTM A182 F316 ASTM A182 F316 ASTM A182 F316
12 Bearing Carbon Steel+Graphite Carbon Steel+Graphite Carbon Steel+Graphite Carbon Steel+Graphite
13 Gasket SS304+Graphite SS316+Graphite SS316+Graphite SS316+Graphite
14 Ball ASTM A105+ENP ASTM A182 F316 ASTM A182 F316 ASTM A182 F316
15 Drain Plug Carbon Steel Carbon Steel Stainless Steel Stainless Steel
16 Ring ASTM A105+ENP Stainless Steel Stainless Steel Stainless Steel
17 Seal Ring Viton AED Viton AED Viton AED Viton AED
18 Seat Ring PTFE, Nylon, PEEK PTFE, Nylon, PEEK PTFE, Nylon, PEEK PTFE, Nylon, PEEK
19 Feet Carbon Steel Carbon Steel Carbon Steel Carbon Steel
20 Injection Valve Carbon Steel Stainless Steel Stainless Steel Stainless Steel
21 Lifting Lug Carbon Steel Stainless Steel Stainless Steel Stainless Steel
22 Body ASTM A105 ASTM A105 ASTM A320 LF2 ASTM A182 F316
23 Safety Valve Carbon Steel Carbon Steel Carbon Steel Carbon Steel
24 Relief Valve Carbon Steel Carbon Steel Stainless Steel Stainless Steel
25 Trunnion Bearing Carbon Steel+Graphite Carbon Steel+Graphite Carbon Steel+Graphite Carbon Steel+Graphite
26 Stem ASTM A182 F6A ASTM A182 F316 ASTM A182 F316 ASTM A182 F316
27 Key Carbon Steel Carbon Steel Carbon Steel Carbon Steel
28 Thrust Washer PTFE PTFE PTFE PTFE
29 O-Ring Viton AED Viton AED Vion AED Vion AED
30 Stuffing Box ASTM A105 ASTM A105 ASTM A350 LF2 ASTM A193 B8
31 Bolt ASTM A193 B7 ASTM A193 B7M ASTM A320 L7 ASTM A193 B8
32 Packing SS304+Graphite SS316+Graphite SS316+Graphite SS316+Graphite
33 Adapter ASTM A105 ASTM A105 ASTM A105 ASTM A182 F316
34 Bolt ASTM A193 B7 ASTM A193 B7M ASTM A320 L7 ASTM A193 B8
35 Nut A194 2H A194 2HM ASTM A194 7 ASTM A194 8
36 Bolt ASTM A193 B7 ASTM A320 L7 ASTM A193 B8 ASTM A193 B8
37 Worm Gear Ductile Iron Ductile Iron Ductile Iron ASTM A194 8


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