b'Double CheckDouble Detector Single Detector Check Reduced Pressure BackowTypes of DevicesSingle Detector Checks: are used in the protection of potable water supplies from unauthorized water usages, or theft. This check valve device is not a backow preventer, and should not be used forHow it Workscross-connection control. In a non-ow condition, the check valves inA backow preventer is a check valve the by-pass and mainline unit are closed. Flows from 0 to 10 GPM willdevice thats installed on a potable ow through the metered bypass. The water meter will record thepiping system that allows water to illicit water usage.This operation, at low ow rates, is accomplished byow in one direction, but never in the designing the differential pressure drop across the bypass line to beopposite direction. Its sole purpose is slightly less than the mainline check valves. Flows in excess of 10 GPMto prevent drinking water from being open the mainline check valve for normal ow. contaminated due to backow.Double Check Backow Preventers (BP): are used in the protectionBackow of water is caused by the of potable water supplies from backow. In a non-ow condition, thepressure differential between the check valves hold a 1 PSI minimum in the direction of ow. In a owupstream (water main) and the condition, the check valves are open proportional to the ow demand.downstream of the backow device.In a backow condition, the check valves close until the resumption of normal ow. Water pressure can be affected Double Detector Check Backows (DDBP): are used in thewhen:protection of potable water supplies from backow and unauthorized There is a break in the water main.water usage. In a non-ow condition, check valves in the by-pass and Water is being pumped from the mainline units are closed. Flows from 0 to 5 GPM will ow through the main water supply during a re.metered bypass. The water meter will record the illicit water usage. This operation at low ow rates is accomplished by designing the A customer is using water at a differential pressure drop across the bypass line to be slightly less thanhigher pressure than the pressure the mainline check valves. Flows in excess of 5 GPM open the mainlinesupplied.check valves for normal ow.Reduced Pressure Backow Preventers (RPZ): are used in the Heavy water use downstream protection of potable water supplies from backow, typically inreduces water pressure upstream.high-hazard applications. In a ow condition, the check valves are The water outlet at the property is open with the pressure between the checks, called the zone, beinghigher than the water main, causing maintained at least 5 PSI lower than the inlet pressure, with the reliefconstant back pressure.valve maintained closed. Should abnormal conditions arise under no ow or reversal of ow, the differential relief valve will open and discharge (to atmosphere) to maintain the zone at least 3 PSI lower than the supply. In resumption of normal ow, the zones differential pressure will resume and the relief valve will close.Visit backo.parkusa.com for more information and design assistance.To request a quote or catalog, visit request.parkusa.com.APPLICATIONSMunicipal Commercial Industrial Medical Facilities'