When maintenance is not required, fully welded valves with no leak paths through the body are available in a more safe solution.
TOP ENTRY BODIES.
When maintenance on line is required, top-entry ball valves are available. With the stem in vertical position this valve design permits disassembly, replacement of all internal parts and seals and reassembly without removing the valve from the line.
For special service conditions (i.e. cryogenic, or high temperatures) O-rings can be replaced by alternative gaskets suitable for the service (e.g. lip seals). In valves working with gas on pressure Classes ≥ 600, the standard O-rings will be replaced with Anti Esplosive decompression (AED) ones.
Other types of drain connection, such as welded or flanged, are available according to purchaser requirements.
Other types of vent valve connection, such as welded or flanged, are available according to purchaser requirements.
Other end connections such as special flanges, as Norsok L-005 compact flanged connections, hub ends, welding ends (pup pieces) or other mechanical joints, may be specified by the purchaser.
Valves with buttweld ends are often required complete with transition pieces. After selection of suitable materials depending on pipe thickness, pipe and valve body material, Dafram can weld transition pieces to the valve during manufacturing process.