Trunnion ball valves have the obturator bounded by Trunnion which do not allow axial displacements of the ball itself in the flow direction; line pressure compresses the seat onto the ball, the contact between surfaces generates the valve sealing. Trunnion standard construction ensures automatic cavity relief in case of overpressure in the body cavity; these valves can be selected for a wide range of applications with no specific limits to sizes and pressures.
GAZAR Trunnion Ball Valve Production are mainly designed to conform API 6D (Specification for pipeline valves) and ANSI B16.34 (Valves Flanged, Threaded and Welding End) or API 6A (Specification for Wellhead and Christmas Tree Equipment) in case of upstream applications. Other related standards such as ANSI B16.5 (Pipe Flanges and Flanged Fittings), ANSI B16.25 (Butt-welding Ends), and ANSI B16.10 (Face to Face and Endto-End Dimensions of Valves) are also used for the design of ball valves.
Also our ball valves are designed to meet FIRE SAFE requirements to BS6755, API 6FA and API 607. Final testing is done to conform API 598 (Valve Inspection and Testing) MSS-SP-61 (Pressure Testing of Steel Valves) API6D (Specification for Pipeline Valves) or API 6A (Specification for Wellhead and Christmas Tree Equipment) requirements. Materials are selected mainly to ASTM standards and when sour service is specified to meet NACE MR-01-75 (Sulfide Stress cracking resistanMetallic Materials for Oilfield Equipment).
Bi-directional Flow
GAZAR ball valves are suitable for bi-directional Sealing.
Soft Seated Valves
The seat design features a deep pocket with a protective lip which makes the design a long lasting design. The seat assembly consists in an outer metallic seat carrier with a soft seat insert. The soft insert is located into a groove in the metallic seat carrier. The complete seat assembly is floating inside valve body and it is energized by a set of springs which load the seat assembly against the ball preventing leakage from behind the seat. Seat assembly is provided with outer O-ring to avoid leakage through the seat carrier and a graphite backup ring which ensure the tightness in case the O-ring is damaged.
Metal Seated Valves
Similar seat construction is done in case of metal seated valve. However the seat in this case consists only in a metallic seat ring (without any insert). The surface in contact with the ball is hard faced with Tungsten Carbide, stellite etc., achieving a minimum hardness of 42 HRC to stellite or convectional hard faced and 78 HRC to Tungsten Carbide or special hard faced. This makes the design long durable and reliable and able to achieve classes V & VI leakage class.
Trunnion Design for Low Torque Operation
Similar seat construction is done in case of metal seated valve. However the seat in this case consists only in a metallic seat ring (without any insert). The surface in contact with the ball is hard faced with Tungsten Carbide, stellite etc., achieving a minimum hardness of 42 HRC to stellite or convectional hard faced and 78 HRC to Tungsten Carbide or special hard faced. This makes the design long durable and reliable and able to achieve classes V & VI leakage class.
Stem Extension for Buried Service
A stem extension is a need when valves are being installed in underground pipeline making the valve operator non accessible. GAZAR offer a wide variety of stem extensions for manual operated valves as well as for actuated valves, including gas over-Oil operated valves. The stem extension includes the complete system of grease injection, actuator gas supply, etc. as a part of it.
Specification
Size Range: 2” – 56” | Pressure Class: ASME 150 – 900 API 2000 -15000 | API Standards: 6D & 6A | API 6D SS | ASME B16.34
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