Matheson Model 18 Single Stage General Purpose Brass Regulator, No Inlet, Delivery Pressure Range 2-50 PSIG, SEQ18NI

This is a Matheson Single Stage Brass regulator with a 1/4 in MNPT outlet connection (with loose 1/4 in hose barb) and 1/4 in FNPT body porting. It comes equipped with 2 inch inlet and delivery pressure gauges, outlet needle valve, Neoprene seals, chrome plated brass bonnet, and a PTFE Teflon seat.

This Matheson, series 18, model 18 regulator is to be used in applications requiring delivery pressures up to 50 PSIG and can accept a maximum inlet pressure of 3000 PSIG. This regulator is suitable for a variety of applications that require gasses that are 99.995% or lower purity. This regulator is not suitable for any application requiring the supply of corrosive gas (non-corrosive gas applications only).

Single-Stage vs. Two-Stage

Both single-stage and two-stage regulators operate by reducing the pressure of gas supplied by a cylinder to an appropriate output level. The intake and delivery pressure ranges of regulators do not depend on how many stages they have, but by each regulators mechanical characteristics. When considering a single vs. a two-stage regulator there are two things to keep in mind: Droop and Supply Pressure Effect. Droop is the decrease in output pressure caused by an increase in flow rate. Supply Pressure Effect is simply the variation in delivery pressure from the cylinder to the regulator.

Single Stage regulators will experience less droop with varying flow rates but a large supply pressure effect and need to be monitored and adjusted by an operator or used in applications where supply pressure will remain constant. Two-Stage regulators inherently control for variations in supply pressure while producing a constant output and therefore can be used without an operator present and in applications which require a very specific delivery pressure. The specification sheet for this series of regulator can be found in the downloadable section as a .PDF.