Regulators

Regulators for specialty and calibration gases

Our premium range of regulators are designed to deliver reliable pressure or flow from gas cylinders. All regulators are available from stock in Australia.

The 110 and 130 series constant flow regulators are suitable for reactive and non-reactive gases and designed to connect directly to disposable / portable gas cylinders. The 110 series constant flow regulators are made with nickel coated brass to ensure suitability for reactive and non-reactive gases. The 130 Series is ideal for service technicians that work with a wide range of gas detection instruments that require calibration at a number of different flow rates.  The 130 series constant flow regulator has 8 different flow settings and is available in brass or stainless steel.

The 300 and 310 series are our demand flow regulators,  designed for use with docking stations and instruments with a sample draw pump. The diaphragm in the demand flow regulator opens sufficiently to match flow requirement, hence the name demand flow regulator.The 300 Series demand flow regulators are designed to connect high pressure gas cylinders via a cylinder Nut and Stem Assembly with a ¼” NPT male thread.  The 310 Series (DFR-1) is our demand flow regulator for portable / disposable gas cylinders with a C-10 outlet connection.

The 180 and 200 series high pressure regulators are suitable for applications with an inlet pressure up to 3,600 PSI. High pressure regulators are available from stock in Australia with Stainless Steel, Nickel Coated Brass and Brass body material. To ensure the highest level of performance from our high pressure regulators all the internal components are stainless steel. If you have a static inlet pressure, most applications are fine with a single stage high pressure regulator, refer to the 180 series scientific regulator brochure for single stage. Applications like gas cylinders with fluctuating inlet pressure require a two stage high pressure regulator, refer to the 200 series scientific regulator brochure.

Please read our application notes below for more information.

Application Notes

Why do we use a two stage regulator instead of a single stage regulator?

Two stage regulators are almost always used on a gas cylinder because the inlet pressure source is the bottle pressure, it is subject to Supply Pressure Effect [SPE]. SPE tells us that as the source pressure decreases, the set point increases. [See our application note on SPE]

Most applications call for a constant set point as the regulator is in use. With a single stage regulator, the set point is going to increase as the source pressure decreases. If the set point is rather low, say 10 PSI as opposed to 500 PSI, the SPE can change the set point by an unacceptable amount.

A two stage regulator is designed to overcome this phenomenon. It is essentially two single stage regulators in series, with the second regulator using the outlet pressure of the first as its source. Normally the first stage is set 150 PSI above the nominal outlet range of the second stage. If the regulator has a 0-100 PSI range, the outlet of the first stage is set to 250 PSI.

If the SPE for the regulator is 1.3% [as for our 0.07 Cv] and we assume a drop of bottle pressure from 3,000 to 250 PSI, then the outlet of the first stage is going to increase from 250 to 286. This increase in the source pressure from the first stage will decrease the set point of the first stage by less than .5 PSI.

With a two stage regulator we get good outlet pressure stability. The trade off is flow restriction. Remember that we set the outlet of the first stage 150 PSI above the inlet of the second stage; therefore when doing a flow calculation for the two stage regulator you only have that much pressure differential driving the gas which will limit the flow.

Here at Scientific Gas Australia, we can make many changes to improve performance – for example we can have a larger Cv on the second stage to increase flow or we can change the differential between stages. The point is that unlike some other suppliers we can be flexible to meet your needs.

Finding the right size regulator for your application

When trying to select the correct pressure regulator for an application, one of the most important considerations is sizing the Cv [Flow Coefficient] of the pressure regulator.

Formulae that will enable you to determine what flow rate you can get for a given Cv value or what minimum Cv you require to insure delivery of a given flow rate are available from a number of different sources.

Scientific Gas can assist you with these calculations if you can provide the appropriate inputs. (Gravity, Temperature, Flow Rate, Inlet Pressure and outlet pressure).

The formulae are calculated, adjusted for safety factor, and calculated in metric units as well.

Cv options for the 180 and 200 series regulators are 0.03, 0.07, 0.24, and 0.30.

When working with the 200 series scientific regulator – remember that you are working in essence with two single stage regulators in series. The output of the first stage is typically set at 150 PSI above the nominal range of the second stage. In other words for a 100 PSI series 200, the inlet to the second stage is 250 PSI – NOT THE FULL BOTTLE PRESSURE.

Accessories

Carry Case for Portable gas cylinders

Gas change-over stations

Gas Regulator Inlet connector for CGA and Australian cylinders

Quick release gas connections to interchange gas supply or instrument

A selection of pressure gauges