Trunnion Mounted Ball Valves – Trunnion Ball Valve Seal

What is a Trunnion Ball Valve?

A trunnion-mounted valve means that the ball is constrained by bearings and is only allowed to rotate, the majority of the hydraulic load is supported by the System constraints, resulting in low bearing pressure and no shaft fatigue.

Product Overview of Trunnion Ball Valve

SIZE RANGE	From 2” – 48”
PRESSURE RANGE	ANSI 150# through ANSI 2500# pressure class
MATERIAL GRADES	A105N, A182-F316 SS, A350-LF2, A350-LF6, and F51 Duplex
PORT SIZES	Full Bore, and Reduced Bore
TRIM MATERIALS	3MIL ENP, 316SS, and F51 Duplex
SEAT INSERT MATERIAL	Devlon (PEEK and others available upon request)
SEAL MATERIALS	HNBR 90 DURO, James Walker 101/985, FKM GLT, and AFLAS
END CONFIGURATIONS	Raised Face (RF), Ring Type Joint (RTJ), Butt Weld (BW), and Flanged X Butt Weld
STANDARD FEATURES	Anti Static device, Anti Blowout Stem, Pressure relief valve to avoid cavity overpressure when applicable, Emergency built-in stem and seat sealant injection system, Fire Safe in accordance with API 607, MR-0175 NACE compliant, Fugitive Emissions compliant
SEAT DESIGN FEATURES	Double Piston Effect, Self Relieving, Combination of options available
VALVE FUNCTIONALITY	Double Block and Bleed (DB&B), Double Isolation and Bleed (DIB-1 or DIB-2)
DESIGN STANDARDS	B16.34, B16.10, B16.5, B16.25, B16.47, Firesafe, Low Emmisions Compliant, CSA Z245.15.2017

Structural Characteristics of Trunnion Ball Valve

Trunnion mounted ball valve is composed of the main valve body and left and right side valves. The sphere is a sphere with a journal at the upper end and a hole at the lower end. The upper part of the valve body has a packing box. There is a sliding bearing at the junction of the ball journal. The lower part of the sphere has a journal hole and a journal-bearing sleeve. A bearing at the bottom of the valve body is inserted into the journal hole at the lower end of the sphere. In this way, the sphere is maintained on the center line of rotation, and there will be no offset when it rotates. There are symmetrically two floating seat assemblies on both sides of the sphere. The seat assembly consists of a metal seat ring, a PTFE seal ring embedded in the seat ring, a rubber O-ring on the outer edge, and coil spring on the back. When the valve closes, the medium force acts on the components of the sealing seat, which makes the valve seat in contact with the sphere, generates contact stress, and achieves effective sealing. The valve stem and packing box are sealed by O-ring rubber.

What is Ball Valve Seal?

The ball valve seat is responsible for sealing the fluid inside and uniformly distributing the seating stress. In soft seat ball valve designs, either an elastomer or polymer is used as the seal and is inserted into a metallic seat ring.

Sealing Principle of Trunnion Mounted Ball Valve

Trunnion Mounted Ball Valve can also be called trunnion type ball valve or trunnion ball valve. Its opening and closing parts are a sphere with two supporting axes, in which there is a passage equal to the diameter of the pipeline, and two floating seats on both sides. When the sphere rotates, it does not deviate from the axis of the supporting shaft on the sphere. The supporting shaft is supported by two sliding bearings, and the valve seat is floating. Under the action of medium force, contact stress is generated when the ball is pushed to the sphere to obtain a reliable seal. Like floating ball valves, valves travel 90 degrees from opening to closing, or from closing to opening.

Among various trunnion ball valve manufacturers, Zeco is the best choice for you. For more information on trunnion mounted ball valves, please visit our website at http://zecovalve.com/.

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