Valves are normally installed in the vessel shell at the inlet/outlet ports or supplied complete with line housings for fitting into pipelines. They can be installed horizontally or vertically. Note : These valves are NOT intended as primary closure or check valves - despite their tight seating.
The valve is normally held closed by a heavy duty stainless steel spring and hydraulic pressure is applied to hold the valve open. When the hydraulic pressure is released, the valve closes rapidly to ensure safe shut-down in the event of an emergency.
Hydraulic pressure can be released by :
Special Trim (seals and springs) available for service down to -450 C