• Fully Welded Body Structure:The valve body is integrally welded from forged steel pipe sections and body forgings using fully automatic Submerged Arc Welding (SAW) or Gas Shielded Arc Welding (GTAW/GMAW). With no intermediate body flange or bolted connections, 100% radiographic testing (RT) and ultrasonic testing (UT) are performed, completely eliminating external leakage paths. The design service life is 30–50 years, matching the service life of the pipeline.

• Power Source:Driven by pipeline natural gas, requiring no external power supply, air source or hydraulic power unit, making it especially suitable for unmanned and remote areas.

• Gas‑Hydraulic Conversion:Natural gas drives hydraulic oil to achieve high torque output through hydraulic cylinders, ensuring smooth and shock‑free operation.

• Adjustable Opening/Closing Speed:Opening and closing time is adjustable via throttle valves, typically from 15 to 60 seconds, preventing water hammer and pipeline surges.

• Under‑Pressure Protection:Automatic shutdown when pipeline pressure falls below the set value, preventing pipeline rupture and medium leakage.

• Local/Remote Control:Supports local manual operation, local pneumatic control, remote SCADA control and Emergency Shutdown (ESD).

• Trunnion‑Mounted Ball:The ball is secured in the valve body bearings by upper and lower trunnions, maintaining precise positioning under high differential pressure and frequent operation conditions to avoid uneven wear of sealing surfaces and ensure long‑term reliable sealing.

• Full Bore / Reduced Bore Optional:Full bore design allows passage of pipeline pigs and intelligent detectors, supporting online pipeline inspection. Reduced bore design optimizes cost efficiency, lowering weight and operating torque.

• Double‑Seat Bi‑Directional Sealing:Independent upstream and downstream seats provide bi‑directional sealing. Seats are available with piston effect (self‑relieving) or double piston effect (DPE) design to meet cavity pressure management requirements under different operating conditions.

• Flanged / Welded End Optional:Butt‑welded (BW) ends are provided as standard, with optional flanged transition ends (RF/RTJ). Welded ends comply with ASME B16.25/API 1104, and flanges conform to ASME B16.5.

Gas Liquid Operated Fully Welded Ball Valve 3D Diagram

J-VALVESSPE can supply a range ofseat types and configurationsto meet specific process needs:

J-VALVES trunnion mounted ball valves standard seat ringsare soft-seated by the use of athermoplastic or elastomeric or Meta

Seats-Tungsten /Chrome carbide /ENP

Single Piston (SPE) , Double Piston effect (DPE) and Combination (SPE x DPE) seats are available.

Seat Princlple

Two independent seat rings grant the sealing, barrieragainst the line pressure actingon the upstream and downstreamsides of the valve which allows the valve tobe bidirectional.

A set ofcoil springs acting, between the upstream side ofeach seatring,andthe body,generate an uniform thrust on theseat which push the same against the ball and grant the sealingfeature with no orverylow pressureinthe line,when the line pressure increasethe thrust actingon theseat increases proportionally and the sealing leatureis granted throughout the fullpressure range.

The J-VALVES SPE trunnion mounted ball valves are available with Double

Block & Bleed in dependent oftheseat type.

Valve seating variations

Seat Design	Single piston effect (SPE)	Double piston effect(DPE)-DIB 1	Combined DIB 2
Bi-directional sealing	Yes	Yes	Yes
Body-Cavity Self relieving	Yes	No	Yes
Double Barrier	No	Yes	Yes (preferred direction only)

Single Piston Effect

Single piston effect (SPE) is the stand ard feature for theseat rings of the J-VALVES SPE trunnion mounted ball valves.

On a SPE seat ring:

The pressure ac tingon the upstream side ofthe seat ringgenerates aforce which push theseattowards the ball.The pressure actingon the downstream side ofthe seatring generates a force which pull theseatring away fromthe ball.

Anyoverpressure which may be generated by the thermal expansion of the fluid trapped in thebodycavity with the ballin fully closed position, will beautomatically dischargedinthe line on the lower pressure side.

Double Piston Effect

Double piston effect(DPE) is a stand ard feature fortheseat rings ofthe J-VALVES trunnion mounted ball valves & recommended forwelded body valves. Ona DPE seat ring, both the pressure acting on the upstream sideof theseatring andthe pressure acting on thedownstreamside of the  seatring, generatea forcewhich push the seattowards the ball.

With th is type ofseat ring,the eventual over press ure whichmay be generated by the thermal expansion ofthe fluidtrappedinthebodyeavitywith theball in fullyclosed position,can be discharged by the use of:

An external safetyrelief device.

The Double Piston Effect grants a double sealingfeature,iftheupstreamseat ringisdamaged, thedown stream seatgrant the sealingfeature of the valve.