An On-Demand Flow Regulator is designed to supply gas only when it is required by the instrument, making it an ideal solution for calibrating and testing process analysers and gas monitoring equipment fitted with internal sampling pumps.
Unlike conventional fixed flow regulators, an on-demand regulator responds directly to the analyser’s sampling system, delivering only the amount of gas the instrument requests. This improves calibration accuracy while significantly reducing unnecessary gas consumption.
Oxford Valves On-Demand Flow Regulators are available for both disposable calibration gas cylinders and refillable high pressure cylinders, allowing the same operating principle to be used across a wide range of applications and cylinder types.
(ODFR-HP attached to a High Pressure Cylinder)
Once connected to the calibration gas cylinder, the regulator remains closed and no gas will flow from the outlet. There are no on/off knobs or adjustment controls to operate.
Gas flow only begins when the analyser or sampling system creates sufficient vacuum to open the regulator diaphragm. As the analyser draws gas into the instrument, the regulator automatically responds and supplies the required flow.
The amount of gas delivered is directly proportional to the analyser’s sampling rate, meaning the instrument effectively controls its own gas supply without the need for flow meters, needle valves or additional flow control equipment.
By allowing the analyser pump to draw gas at its normal operating flow rate, the calibration conditions more closely match the instrument’s real operating environment, helping to improve repeatability and calibration accuracy.
Many traditional calibration setups rely on gas bags, vent tees or “T” piece assemblies to manage gas flow and pressure. While these methods can work, they often introduce additional complexity and increase the risk of leaks, dilution from ambient air or inconsistent gas delivery.
As tubing ages, fittings loosen or vent arrangements are modified in the field, atmospheric air can enter the calibration system and dilute the gas mixture before it reaches the analyser. This can result in inaccurate readings, failed calibrations or poor repeatability between tests.
An On-Demand Flow Regulator removes these variables by allowing the instrument to control gas delivery directly, providing a simpler, cleaner and more reliable calibration method.
Oxford Valves On-Demand Flow Regulators are available in both nickel plated brass and stainless steel construction to suit a wide range of gas mixtures and applications.
For corrosive or reactive gases such as ammonia, chlorine, hydrogen sulphide, hydrogen chloride or nitrogen dioxide, stainless steel construction is strongly recommended to maintain gas stability, protect regulator components and maximise service life.
Whether calibrating portable analysers, fixed process monitoring systems or automated sampling equipment, an On-Demand Flow Regulator provides an accurate, efficient and cost-effective method of delivering calibration gas exactly when it is needed.