Design D4 Control Valve
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If the control valve requires maintenance, the trim and packing can be maintained by removing the patented deep-bore hammer nut and lifting the actuator/bonnet assembly off the valve without disassembling the actuator.
- Safer Bonnet / Valve Body Connection — Unique design provides additional protection if disassembly of bonnet/valve body connection is inadvertently started while there is still pressure in the valve body. Pins mounted in the valve bonnet ensure the bonnet disengages from the valve bodyas the hammer nut is removed.
- Heavy-Duty Guiding — Massive guiding positively aligns the valve plug in the seat ring for reliable service.
The screwed-in seat ring completely encloses the seat ring gasket. - Severe Service Capability with ST Carbide Trim — D4 valves are available with ST (super-tough) tungsten carbide trim for erosive service. Fisher ST Carbide trim is designed specifically for severe service applications in the oil and gas industry.
- Live-loaded Packing System — The packing system provides a superior stem seal to prevent the loss of valuable or hazardous process fluids or gases.
It features field-proven Fisher ENVIRO-SEAL® packing technology, to provide reduced packing maintenance. - NACE Constructions—NACE compatible trim is available with the Design D4 control valve.
These constructions are compatible with the recommendations of NACE MR0175 / ISO15156