Sigmamotor back pressure valves prevent siphoning and varying rates of dosage from fluctuating downstream pressure by enacting positive discharge pressure in your metering pump system. The valves are set at 50psi but are easily adjusted in the field. Field adjustment is possible with the adjustment screw under the screw-off cap.
Generally, the back pressure valve can be installed anywhere in the discharge line, provided there is some downstream pressure at the dosage point. If there is no downstream pressure the back pressure valve should be installed at the dosage point to prevent siphoning and drainage of the chemical line.