Ebsray® RV Series Pressure and Flow Modulating (PFM) System Equipment is designed and precision built for applications in pumping systems which demand accurate Constant Pressure Control (CPC) or Flow Modulation/Control. CPC pump systems historically required expensive variable-speed drives, complicated variable displacement pumps and inefficient bypass-type valves. The Ebsray PFM System is a cost-effective alternative that enables constant pressure control from simple input signals with most types and principles of pumps or pumping systems irrespective of changes in viscosity.