Fully Welded Trunnion Ball Valve
Fully welded ball valves feature a trunnion-mounted ball and a forged steel body that is constructed by welding all parts to avoid external leakage.
The all-welded ball valve gland and valve body manufactured by Relia adopt a welded structure, which can reduce the external leakage point of the valve and is a real all-welded ball valve, which is very helpful for the control of external leakage. Inspection and maintenance of such valves may be executed on live line.
Full-welded ball valves are designed for above-ground and underground applications in gas transportation, distribution, and storage systems as on-off valves. A fully welded design prevents external leakage and offers a long, maintenance-free service life.
Features and Benifit:
All welding jobs are performed as per drawings, instructions, client specifications, and welding procedure specifications that are qualified according to ASME Sec IX under the supervision of a welding engineer. Relia has a lot of existing welding procedures that cover a great variety of different applications and is fully capable of developing new ones depending on the required applications. All welders are qualified according to ASME Sec IX and fully capable of carrying out the job according to written instructions, drawings, and procedures.
Trunnion-mounted ball valves have additional anchoring at the top and bottom of the ball. The two trunnions absorb the thrust generated by the line pressure, preventing excess friction between the ball and seats. Therefore, operating torques stay low, even at full working pressures.
Automatic Internal Relief of Body Cavity Pressure
Relief of excess body cavity pressure is automatic, avoiding dangerous pressure buildup. Any pressure greater than the downstream line pressure plus spring force pushes the downstream seat away from the ball, allowing the pressure to escape into the pipeline. This design delivers full protection to the valve body, prevents leaks, and enhances safety in case of fire.
Low-Emission Stem Sealing
The stem is sealed by two static o-rings and a graphite packing held in place by the mounting flange. This triple stem sealing arrangement provides superior fugitive emission control certified according to ISO 15848-1.
Anti-Blow-Out Stem Design
The stem design of Relia Full Welded Ball Valves is blow-out proof, which prevents ejection of the stem when the valves are under pressure. This design is fully compliant with API 6D requirements.
All Relia Full Welded Ball Valves are equipped with an antistatic device that creates a ground path and ensures electrical conductivity through all metallic valve components.
Relia Full Welded Ball Valves are fire-safe by standard design. Fire-safe tests were carried out and certified according to API 6FA, API 607.
Valve Transition Pieces (Pups)
Full Welded Ball Valves with butt-welding ends can be supplied with valve transition pieces (pups) in order to prevent damaging soft seats during welding or post weld heat treatment on site. Another reason to use a transition piece is to avoid dissimilar welds on site when the valve body material and pipe material are different.
Bypass lines are used in order to compensate for high pressure differences and vent dead space before actuating valves. Relia full-welded ball valves can be equipped with a bypass upon request.
Stem Extension for Remote Operation
When the fully welded ball valve is installed underground, the high head allows the controls to be accessed above ground. Additional options such as stub-up and auxiliary valves are available. Designed and constructed to withstand harsh environments, it has proven itself in use for many years.
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Valve type (ball, gate, globe, check etc.), valve size, pressure class, valve material, and end connection (flanged, butt welding etc.)