Back pressure valves are designed to enhance the performance of any chemical feed system by applying a constant pressure to the discharge of the pump. This will ensure positive ball seating in the pump check valve, a positive head differential and a constant minimum discharge head. The valve also acts as an anti-siphon valve.
Back pressure valves apply positive discharge pressure to a metering pump system to prevent siphoning and eliminate varying dosage rates caused by fluctuating downstream pressure. The diaphragm is held against the valve seat by an internal spring. When the preset pressure is exceeded, the diaphragm is forced up and chemical flows through the valve to the injection point. The valves are preset for 50 psi, however they are field adjustable from 10 - 150 psi via the adjustment screw. Installation should be as close to the injection point as possible to prevent chemical line drainage and it is most important that all chemical system equipment such as pulsation dampeners and pressure gauges are between the pump and back pressure valve.