The valves are externally adjustable, and unlike shear relief valves which use common nails to trigger the valve, Weir SPM's Full Bore Unloading Valve utilizes nitrogen or rig air (properly filtered) to activate opening and closing. This model is available in 3" and 4" sizes. Operating pressures range from 5,000 psi to 20,000 psi (3" model). Standard service and sour gas models are available.

Remote Relief
Utilized together, the Full Bore Unloading Valve and Remote Control Panel increase safety for operators on drilling sites.  Weir SPM designed a Remote Control Panel to work in conjunction with Weir SPM's Full Bore Unloading Valve (drilling applications) and the Emergency Backpressure Relief Valve (well service applications). The Remote Control Panel's primary function is to regulate the flow of air or nitrogen to the relief valve from a designated control station, allowing the operator to change the pressure relief settings with the turn of a knob at a safe distance.