Back Pressure/Relief Valves

Series: SB
Inlet Connection: 1/4″- 4″
Instrument Connection: True Union Socket, Threaded or ChemFlare, Spigot Bodies with Plain, Socket, Threaded or Flanges
Diaphragm: PTFE Bonded EPDM
Seats/Seals: EPDM, FPM


SB Series Back Pressure Relief Valves

Chemline’s SB Series back pressure relief valves are designed for long maintenance-free life. They are designed for superior performance in dosing systems. Different models are available. Each has advantages for different applications.

How they Work

Chemline SB Series Back Pressure/Relief Valves have two functions: as a back pressure valve, installed in-line downstream of a pump, the back pressure below the metering pump is maintained. When installed in the branch of a tee they are pressure relief valves. The valves stays closed until inlet pressure reaches the set pressure which is adjusted by turning the spring tensioning bolt. Inlet pressure acts against a PTFE bonded diaphragm, opening the seat to allow flow until the inlet pressure again equals the set pressure.

✓ Choice of PVC, Polypropylene or PVDF construction
Will handle a wide range of chemical applications and temperatures up to 100C (212 deg. F).
✓ Designed for superior Performance
High flow rates vs. overpressures
Low hysteresis (“backlash”)
No chatter
Long Cycle life

✓ True Union ends up to 2”
Easy Installation and maintenance
Leaky threads eliminated

✓ Sizes up to 4”

Back Pressure/Relief Valve Selection


Model Sizes True Union ChemFlare Set pressure Range Size Price Value Major Features
SB17 1/4″ – 3/8″ Yes 3/8″ 7.5 to 150 psi mini good fits tight spaces
SB12 3/8″ – 2″ Yes 3/8″ – 1″ 5 to 150 psi medium good built-in check function, unchanging opening pressure
SB12 2-1/2″-3″ no 7.5 to 150 psi large good built-in check function, unchanging opening pressure
SB12 4″ no 7.5 to 90 psi large good built-in check function, unchanging opening pressure
SB18 3/8″ – 2″ Yes 3/8″ – 1″ 7.5 to 150 psi medium best recommended for dosing – not too sensitive



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