Many metering pump applications dispense to atmospheric conditions or into a process with less than 1.5bar pressure and more typically, into a process with erratic system pressure. These applications require back pressure to ensure a constant pressure for the discharge check assembly on the metering pump to work properly. It is crucial that Back Pressure Valves be installed in the discharge piping of the pump to ensure a constant pressure for the discharge check assembly to work under. This allows for the repeatability of a constant fluid discharge per stroke, and accuracy desired. Additionally, back pressure valves automatically provide anti-siphon protection and are available in a variety of sizes and materials.