The Cla-Val Model 40-01 Rate of Flow Control Valve preventsexcessive flow by limiting flow to a preselected maximum rate,regardless of changing line pressure. It is a hydraulically operated, pilotcontrolled, diaphragm valve. The pilot control responds to thedifferential pressure produced across an orifice plate installeddownstream of the valve. Accurate control is assured as very smallchanges in the controlling differential pressure produce immediatecorrective action of the main valve. Flow rate adjustments are made byturning an adjusting screw on the pilot control.The Model 40-01 includes an orifice plate with a holder that should beinstalled one to five pipe diameters downstream of the valve. If thecheck feature option is added and a pressure reversal occurs, theand the valve closes to prevent return flow. See X52E data sheet fordownstream pressure is admitted into the main valve cover chambersizing selection.