• F304 Austenitic Stainless Steel Construction:The valve body is forged from ASTM A182 F304 (0Cr18Ni9) steel. Its face‑centered cubic structure ensures excellent toughness even at cryogenic temperature down to -196℃, with no risk of low‑temperature brittle transition. It features good intergranular corrosion resistance, suitable for service ranging from ultra‑low temperature to medium temperature.

• Integral Forged Three‑Piece Structure:The main body and both end caps are fully machined from forgings with compact grain structure and free of casting defects. The symmetrical three‑piece design provides uniform stress distribution and allows online disassembly and maintenance without removing the entire valve from the pipeline.

• Fixed Ball / Trunnion Supported Design:The ball is precisely supported and fixed by upper and lower trunnions, achieving sealing independent of medium pressure. Operating torque is low and stable, completely eliminating ball deformation and sealing failure risks under 8‑inch large‑bore and 900LB high‑pressure conditions.

• Cryogenic Adapted Design:The extended stem structure positions the stuffing box away from the ultra‑low temperature zone to prevent freezing and failure of sealing components. The extended bonnet neck provides sufficient space for insulation cladding, ensuring smooth operation at -196℃.

• Optional Vacuum Insulation Structure:Vacuum jacket or foam insulation layer can be optionally installed outside the valve body to minimize cold loss, prevent frost and ice formation on the outer surface, and ensure operator safety.

• Double‑Seat Cryogenic Sealing:Modified PTFE or metal seal with flexible graphite seats is adopted to achieve reliable bi‑directional sealing. Double Piston Effect (DPE) or Double Isolation and Bleed (DIB‑1/DIB‑2) configuration is available to meet strict isolation requirements in cryogenic systems.

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.