• A105 Fully Welded Body Structure: The valve body is integrally welded from ASTM A105 forged pipe sections and body forgings using fully automatic Submerged Arc Welding (SAW) or Gas Shielded Arc Welding (GTAW/GMAW). It eliminates the body mid-flange and bolted connections. 100% Radiographic Testing (RT) and Ultrasonic Testing (UT) are performed to completely eliminate external leakage paths. The design service life is 30–50 years, matching the pipeline life.

• 12-Inch Large Bore Design: DN300 nominal bore satisfies high-flow media transportation requirements. Full bore design allows smooth passage of pigs and intelligent inspection devices; reduced bore is optional for improved economy, lower weight and reduced operating torque.

• 300LB Medium Pressure Class: Class 300 (PN50) pressure rating, with a maximum working pressure of 5.0 MPa at ambient temperature, suitable for medium-pressure piping systems such as long-distance natural gas pipelines, urban gas distribution and district heating.

• Trunnion-Mounted Ball: The ball is fixed in the body bearings via upper and lower trunnions, maintaining precise positioning under 300LB pressure differential and thermal cycling conditions. This prevents ball offset and sealing surface eccentric wear common in large-bore floating ball valves, ensuring long-term reliable sealing.

• On-Off Type: Provides fully open / fully closed two-position control, with adjustable stroke time of 30–180 seconds, supporting local / remote / stop three-state control.

• Modulating Type: Equipped with a 4–20mA positioner to achieve 0–100% continuous regulation with control accuracy of ±1%, supporting PID control loops.

• Intelligent Type: Integrated with Profibus / Modbus / HART communication protocols, enabling remote diagnostics, fault pre-alarm and predictive maintenance.

• High Torque Output: Optimized for 12-inch large-bore applications, with output torque exceeding 50,000 Nm.

• Ingress Protection: IP68, waterproof and dustproof, suitable for buried, humid and harsh environments.

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

12" 300LB A105 Electric Fully Welded Trunnion Mounted Ball Valves 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.