• Fully Welded Body Structure:The valve body is connected to the pipeline by full butt weld without flanged sealing faces or bolted joints, completely eliminating external leakage risks. It features a compact structure and light weight, allows direct buried installation, and is maintenance‑free throughout its service life.

• Trunnion Mounted Ball Design:The ball is supported and fixed by upper and lower trunnions. Initial sealing is achieved by seat spring preloading, with medium pressure assisting to enhance sealing performance. It features low operating torque and is suitable for high‑pressure, large‑bore applications, preventing excessive ball displacement caused by pressure differential that could lead to seal failure.

• Power Source:Powered by line natural gas or nitrogen without external power supply, ideal for field applications without electricity.

• Gas‑Hydraulic Conversion:Gas drives hydraulic oil to achieve smooth and controllable valve operation.

• Quick Shut‑down:Fast response, completing closure within seconds in emergency situations.

• Local / Remote Control:Supports local manual operation, local pneumatic control, remote SCADA control and automatic emergency shutdown.

• Line Rupture Protection (Rupture Pin / LPS):Automatically closes the valve upon detecting an excessive pressure drop rate to prevent escalation of pipeline rupture incidents.

• Full Bore Design:Flow passage diameter matches the pipeline inner diameter with extremely low pressure drop, allowing smooth passage of pipeline pigs to meet the requirements of cleaning and inspection for long‑distance pipelines.

• Suitable for Direct Buried Installation:The fully welded structure has no external leakage points and can be installed directly underground without valve pits or with greatly reduced pit size. Extended stem and top protective casing are optional for ground‑level operation.

Gas Hydraulic Actuated Trunnion Mounted 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.