• CF8 Cast Stainless Steel Valve Body: Precision-cast from ASTM A351 CF8 (304 stainless steel) with stable austenitic microstructure and excellent low-temperature toughness. Charpy V-notch impact energy is ≥27 J at -196℃, eliminating the risk of brittle fracture under cryogenic service. 304 stainless steel provides superior resistance to general corrosion and intergranular corrosion, making it suitable for clean low-temperature media.

• 28-inch Extra-Large Bore Design: Nominal diameter DN700 satisfies the delivery demand for ultra-large flow rates of cryogenic media, serving as a mainline size in industrial piping systems. It is widely used in main liquid inlet/outlet lines of large LNG storage tanks, cryogenic air headers of air separation units, and similar applications.

• Class 300 Medium Pressure Rating: Class 300 (PN50) pressure class with a maximum working pressure of 5.0 MPa at ambient temperature, suitable for general industrial conditions such as low-pressure LNG storage and transportation, and cryogenic pipelines in air separation plants.

• Trunnion-Mounted Ball: The ball is secured in body bearings by upper and lower trunnions, maintaining precise positioning under -196℃ cryogenic contraction, Class 300 differential pressure, and thermal cycling. It prevents ball deflection and uneven sealing surface wear common in extra-large bore floating ball valves, ensuring long-term reliable sealing under extreme conditions.

• Extended Cryogenic Bonnet: The bonnet is extended above the seat ring to keep the packing gland area away from -196℃ low-temperature media. The temperature gradient ensures the packing operates above 0℃, preventing stem freezing and operational seizure. Extended dimensions comply with BS 6364 / ISO 28921-1. For the 28-inch size, the standard extended length is typically ≥1000 mm and can be customized for ground-level operation.

• Optional Vacuum Insulation Layer: Vacuum jacket or polyurethane foam insulation can be fitted to the bonnet and body, reducing cold loss by over 60%, preventing external surface frosting and personnel frostbite, and improving energy efficiency in large-scale cryogenic systems.

Cryogenic Trunnion Mounted Ball Valve Extended Stem 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.