Fully Welded Trunnion Mounted Ball Valve

• Fully Welded Body Structure: The valve body is integrally welded from forged pipe sections, forged flange necks and body forgings using fully automatic Submerged Arc Welding (SAW) or Gas Shielded Arc Welding (GTAW/GMAW). With no body intermediate flange or bolted connections, it completely eliminates external leakage paths, reducing the leakage probability to less than 1/100 of that of conventional flanged valves.

• Trunnion-Mounted Ball: The ball is secured in the body bearings by upper and lower trunnions, maintaining precise positioning under high differential pressure and varying temperature conditions, preventing uneven wear of sealing surfaces and ensuring long-term reliable sealing. It is suitable for large-bore, high differential pressure and frequent operation applications.

• Full Bore Design: The ball passage matches the inner diameter of the pipeline, with a flow resistance coefficient close to zero (maximized Kv/Cv values) and extremely low pressure drop. It allows smooth passage of pigs and intelligent inline inspection tools, supporting online pipeline inspection and internal testing.

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

• Fire-Safe Design: Compliant with API 607/ISO 10497 standards. In the event of fire damage to soft seats, metal seats contact the ball to form a metallic seal, preventing medium leakage during fire incidents.

• Anti-Static Device: Built-in anti-static spring ensures effective discharge of static electricity between the ball, stem and valve body, preventing explosions caused by static accumulation.

• Blowout-Proof Stem Design: The bottom-entry stem is equipped with an anti-blowout shoulder. Even if the packing gland is accidentally removed, the stem remains retained by the valve body, ensuring operational safety.

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

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.