The Model QX004G Rate of Flow Control Valve
prevents excessive flow by limiting flow to a preselected maximum rate, regardless of changing line pressure. It is a hydraulically operated, pilot controlled, diaphragm valve. The pilot control responds to the differential pressure produced across an orifice plate installed downstream of the valve. Accurate control is assured as very small changes in the controlling differential pressure produce immediate corrective action of the main valve. Flow rate adjustments are made By turning an adjusting screw on the pilot control.
The Model includes an orifice plate with a holder that should be installed one to five pipe diameters downstream of the Valve.
To guarantee accurate control of flow rate, there are several orifice plate with different hole optional for each size, see the additional table for selection of orifice.