Pneumatic Pressure Regulators

G (general): standard regulator with a manual adjustment knob — needs an external pressure gauge plumbed in. M (manometer): regulator with a built-in pressure gauge in the body — simpler installation, more compact. R (reverse flow): regulator allows air to flow backwards through it (e.g. when the compressor is shut off, system air can vent back). Conventional systems use G or M; R is for specialised automated systems.

Manual (R72G etc.): operator turns a knob — simple and quick, but each change requires a hand. Pilot-operated (R40, R41, 11-808): a separate air control signal sets the output pressure — automatic, remote or program-driven. Use pilot when (1) the regulator is far from the operator, (2) different programs need different pressures, or (3) the system controller (PLC) changes pressure on the fly.

Precision regulators (RM1H, RM1L) hold output pressure far more tightly than standard industrial regulators, independent of input pressure or flow changes. Use precision for: pneumatic measurement instruments, calibration systems, fine-control tools (precision adhesive dispensing), pharma metering. If the end component needs stability within ±0.1 bar, use precision.

Two parameters: (1) nominal flow (l/min — Norgren provides flow charts on each datasheet) and (2) port size (G1/4, G3/8, G1/2, G1). Symptoms of mis-sizing: output pressure 'sags' under heavier load (undersized), or the regulator 'hunts' (oversized, unstable). Norgren standard practice: size for ~70-80% of input flow — gives stable hold with headroom.

The 11-818 Series and R91-Series include built-in relief: if downstream pressure exceeds the setpoint (e.g. due to backflow or a closed downstream valve), the regulator vents air through an integrated relief valve. This prevents downstream over-pressure — critical in pneumatic systems where over-pressure destroys seals or risks rupture.