Pressure Sustaining Valve

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The Chemguard pressure-sustaining valve is used in balanced pressure foam proportioning systems to maintain a set system pressure. The valve is used in combination with the foam concentrate pump to maintain consistent upstream pressure regardless of system demand.


The basic valve is a single seated, line pressure operated, diaphragm actuated, pilot controlled globe valve. The valve is sealed by means of a corrosion resistant seat and resilient, rectangular seat disc. These and other parts are replaceable in the field; and all such service and adjustments are possible without removing the valve from the system pipework. The stem of the valve is guided top and bottom by integral bushings. All internal and external ferrous surfaces are coated with a high quality, two part epoxy primer; the exterior then receives a coat of baked enamel paint. The pilot control system includes a direct acting, normally closed, spring loaded diaphragm actuated pilot valve with the stem guided between the diaphragm assembly and seat disc. To ensure precise pressure regulation, the appropriately rated pilot valve is field adjustable within the pressure control range of the spring. Such adjustment is not to exceed a ratio of 6:1. The valve is operationally and hydrostatically tested with the appropriate pilot in place prior to shipping and carries a one-year limited warranty against failure due to defects in workmanship or materials.


  • The valve is provided with a custom engineered sensing line “flush” feature to ensure that foam concentrates do not congeal in the pilot actuation system, rendering the valve inoperable.
  • Quickly relieves excess pressure or back pressure
  • Operates automatically from line pressure
  • Normally closed, direct acting, spring-loaded pilot for pressure adjustments between 100-300 psig, using a single adjusting screw.
  • Heavy duty, nylon reinforced, viton diaphragm isolates upper chamber operating pressure from lower chamber line pressure.
  • Diaphragm assembly, guided top and bottom, is the only moving part of the main valve.
  • No packing glands or stuffing boxes to allow leaking of control fluid
  • Rectangular soft seat provides drip-tight seal for extended valve service.
  • Easily repaired and adjusted without removal from the line.
  • Inlet port tapping can be used for a pressure gauge. All valves are hydrostatically and flow tested prior to shipping with specified pilot set-points factory set.


Model CPSV (Brass)

Main Valve: Body/ Bonnet - Bronze
Control Pilot: Body/Bonnet - Bronze B62
Tubing/Fittings: Copper/Brass


Part No: Size End Connection
CPSV1.25 1-1/4” Flanged, ANSI 150 lbs.
CPSV1.5 1-1/2” Flanged, ANSI 150 lbs.
CPSV2 2” Flanged, ANSI 150 lbs.
CPSV3 3” Flanged, ANSI 150 lbs.
CPSV4 4” Flanged, ANSI 150 lbs.
CPSV6 6” Flanged, ANSI 150 lbs.