Back Pressure Valves/Relief Valves for Low-Pressure Metering Pumps

Backpressure, antisiphon and pressure relief valves

Backpressure (2-port) valves may be used in-line to provide a constant discharge pressure for protection from siphoning, or they may be teed off of the discharge line for pressure relief, discharging back to the source tank or to the pump suction line to create a bypass.

Pressure relief (3-port) valves are mounted in the discharge line, featuring a separate relief port which discharges back to the source tank or to the pump suction line to create a bypass.

Backpressure valves provide several functions: they improve repeatability by providing a constant discharge pressure; they provide antisiphon protection for discharge into pressurized water lines or vacuums, or where suction head exceeds discharge head; and they minimize pulsation when used in conjunction with a pulsation dampener.

In-line backpressure/antisiphon and pressure relief valves

These adjustable backpressure (2-port) and pressure relief (3-port) valves have FNPT ports and require tubing adapters for use with flexible tubing.

Can be adjusted with screwdriver.

Dimensions in inches (mm)

Multifunction Valve

Pressure maintenance/relief valve for mounting directly on the dosing head of the pump with the following functions:

• Back pressure valve, opening pressure approx. 1.5 bar, with free drain or priming pressure on the suction side (black rotary dial)
• Relief valve, opening pressure approx. 6, 10 or 16 bar (red rotary dial)
• Priming aid when back pressure is present, no need to loosen the pressure line
• Relieves the pressure line, e.g. before service work

The multi-function valve is operated via smooth-running rotary dials that automatically return to their original position when released. This guarantees safe operation even when access is difficult. The multi-function valve is designed in PVDF materials and can be used for dosing many chemicals.

Attention: Back pressure valves are not absolutely tight shut-off devices! The installation instructions in the operating instructions must be observed!

Caution: The bypass line must always be connected.

Materials in Contact with the Medium

For material version PP, PV, NP, TT

Pressure Relief Valves

1/4" FNPT Backpressure Valves (2-port)

1/4" FNPT Backpressure Valves (3-port)

Tubing Adapters

(1 required per valve port): 1/4" x 3/16" tubing x 1/4" MNPT

1/2" FNPT Backpressure Valves (2-port)

1/2" FNPT Backpressure Valves (3-port)

Tubing Adapters

(1 required per valve port): 1/2" x 3/8" tubing x 1/2" MNPT

3/4" FNPT Backpressure Valves (2-port)

3/4" FNPT Backpressure Valves (3-port)

1" FNPT Backpressure Valves (2-port)

1" FNPT Backpressure Valves (3-port)

1-1/2" FNPT Backpressure Valves (2-port)

1-1/2" FNPT Backpressure Valves (3-port)

2" FNPT Backpressure Valves (2-port)

2" FNPT Backpressure Valves (3-port)

Spare Parts Sets

Contains 1 of each: compression spring, diaphragm, spring plate, and pressure adj. disc.

Spare Diaphragms

High pressure relief valve, adjustable, 1/4" and 1/2" NPT for Sigma X, Makro HK and ProMus pumps

Can also be used as a backpressure valve for < 30 gph (113 l/h).These valves are without springs, which must be ordered separately.