Seats Special Features
On request, two other Trunnion mounted valve designs are available:
.When maintenance is not required, fully welded valves with no leak paths through the body are available in a more safe solution..
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.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 the 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-ring 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.
.For temperature range greater than -10/+120°C.
.For temperature range upon 250°C.
.For special fluids.
.For cryogenic applications.
.Suggested for valves working with natural gas at design pressure up to class 600.
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.Hardfaced Ball and seats to provide a positive seating action in case of abrasive service or in case that the high service temperature don’t allow the use of any kind soft seat insert material.
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.Dafram ball valves can be equipped with ports to inject a suitable sealant to restore seat sealing in the event of damage to the soft seat inserts.
.Dafram ball valves can be equipped with ports to inject a suitable sealant to restore stem sealing in the event of damage to the soft stem seals.
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.Extended bonnets and stems are available for valves working in extreme low or high temperatures (below – 46°C and above 200°C) to increase the distance between the body and the sealing area of the stem.
.For valves to be installed underground, suitable extended stems are available. In this case all drain, vent and emergency sealant lines are extended and the relevant pipes are firmly attached to the stem extension.
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