Dafram Top Entry Ball Valves
developed an advanced design of the top-entry ball valves, in a complete wide range of diameters and pressure classes. Top-entry valves are the perfect choice when on line maintenance is required.
With stem in vertical position it is possible to remove the bonnet the valve allowing free access to the body cavity without dismantling the valve from the line. A set of special maintenance tools permits to take out both ball and seat-rings, this maintenance operation requires very little space around the valve, thus allowing it in areas where space is a limiting factor.
Top Entry construction is available in forged or cast execution, one piece symmetric body closed by a bolted bonnet. The range is both for Full and Reduced bore, pressure ANSI class from 150 to 2500 , with all possible combination of ENDS connections: flanged (RF-RTJ), butt welding and HUB ends.
The top-entry ball valve standard configuration is soft seated trunnion mounted with self-relieving seats, anti-blowout stem, antistatic device, fire-safe certified. To comply with technical requests they can be provided with particular features as double block and bleed, double piston effect construction, stem extensions, secondary tightness injection fittings, metal seats, transition pieces (pup pieces), special face to face and bore sizes (piggable), PTFE spring energized lip seals in case of cryogenic applications or hazardous fluids.
These valves have complete flexibility in the use of materials for body and trim along with seal gasket selections. For this reason, they are suitable for the most severe applications which can be encountered onshore, offshore and in the process industry.
The bonnet-body construction allows the use of different grades of carbon steel, stainless steel and exotic alloys thus complying with the most severe service conditions.
Top-entry construction is also available for special applications as:
- Sour service ball valve
- High temperature ball valve
- Cryogenic ball valve
- Underground ball valve
- Metal Seated ball valve
- High Alloy ball valve
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