Regulators can be single-stage or multi-stage (two stage). A single stage regulator will accept a high variable inlet pressure and allow adjustment of a lower steady outlet pressure. Unfortunately, in the case of permanent and dissolved gases, single stage regulators can exhibit a tendency to rising outlet pressure as, the cylinder they are connected to empties.

As the cylinder empties, the regulator valve spring pushes the valve further open. If a steady outlet pressure is needed this can be, at least, troublesome. Liquefied gases have less tendency to this problem as the single stage regulator accepts vapour pressure, which varies with ambient temperature not cylinder contents.

Consequently, two-stage regulators are favoured for:
• steady outlet pressure
• finer control over outlet pressure

These benefits are achieved by having two regulators joined in series within one piece of equipment. Tied diaphragm means that as the user closes the regulator down a positive (rather than passive) force is exerted automatically on the valve, ensuring positive shut-off.

Gas control equipment cannot be expected to last indefinitely and old regulators have failed in service. Regulators are precision instruments and must not be handled violently or allowed to get dirty.

Proposed checking procedure

1. List the scheduled maintenance checks to be carried out at least annually. Keep a record and record alongside it any functional checks recommended by the supplier. Ensure that no unauthorised repairs have been carried out.
   
   
2. List scheduled replacement items. The manufacturer will have a safe working life for each item, which must be replaced according to their instructions.

For cylinder gases a regulator life of 5 years will generally be quoted*. A regulator will age irrespective of the amount of use it is put to. Our regulators are 'tagged' before despatch with Serial No., Date of Manufacture and Expiry Date.

The regulator controls pressure, but not flow. If you need flow control, connect a suitable flow gauge or flow meter. Such items should also have an appropriate care and maintenance programme.

Other items of gas control equipment may well be necessary in a laboratory gas system. If, for example, a fuel gas is mixed with an oxidising gas and the mixture is then burned, non-return valves and flame arresting elements such as flashback arrestors would be prudent.

Purging, and the mechanisms to allow this, may be necessary to ensure gas purity and, not least, safety to the person changing the cylinder. Pressure relief could be considered. A pressure regulator failure may not only be a potentially serious safety issue but could also damage a sensitive piece of equipment. An additional fail-safe device such as an excess flow valve to detect the effect of a leak and automatically isolate the supply may be fitted.

*In corrosive gas service, this interval is reduced to two years. Stainless steel regulators for high purity and/or corrosive service are also available from Gas Safety UK - prices & details are available on request.

Manufactured under BS EN ISO 9001 quality management systems

Design & construction tailored to meet the requirements of BS EN ISO 2503

Safety pattern pressure gauges

300 Bar valves

Cone inlet filter

Stainless steel HP diaphragms*

Unperforated neoprene LP diaphragms*

Bottom or side entry available (PLEASE SPECIFY WHEN ORDERING. Bottom-entry regulators best suit top-outlet cylinder valves and side-entry regulators are better suited to side-outlet cylinder valves)

(* Both the HP & LP diaphragms in the 'High Purity' regulators [A.15, A.16] are manufactured from stainless steel. These models also have PTFE seals fitted throughout and are suitable for use on gas products up 99.999% purity)

*Important Note

Our regulators are supplied with a 'RegTag' prior to shipping. The RegTag provides an obvious record of the item's serial number, date of manufacture and supply, date for next inspection and a do not use after date. The RegTag also includes a warning to end user to check the item each time before use.

You can buy your own RegTags too...
(PART NUMBER: 99-103