The method of selecting proper regulator

A regulator is a device that can control the pressure to a certain extent in case of a sudden fluctuation of gas flow and moderate it.

Main parts of the regulator

۱.The loading part consists of a weight, spring, gas pressure.

۲.Measuring part or comparatordiaphragm.

۳.Restractor (set orifice)

The regulators are available in spring-loaded and Pilot Regulator-operated models.
In pilot-controlled regulators, the output pressure changes is compared with spring force to the other pilot’s regulator, and the result is applied as gas pressure to the main regulator diaphragm, in other words, the output pressure changes are strengthened and then the prevents the change at valve.

Pilot is a spring-loaded regulator that feeds on the input pressure and provides the output pressure in proportion to the compression ratio of the spring. The pressure is applied as the steering pressure on the main regulator.

The technical characteristic that is important in selecting regulators is their capacity, which is directly related to the input and output pressure and the gas density and its body shape, so that the ratio between the input pressure (P1) and the output  pressure (P2) determines the type of output flow from the regulator. And if P2 <P1/ 2 then the flow is absolute critical, and if P2 = P1 / 2, the flow is critical and if P2> P1/2 the flow will be noncritical.

If k is the constant coefficient of the regulator, which depends on the structure of the regulator and the fluid type, the total flow equation in the regulators is:

‎ Q=K(P2(P1-P2))½ ‎

The requlator capacity is easily calculated for different pressures based on the above equation and available tables.

A regulator is a device that decreases the high gas pressure in a cylinder or a process line down to a lower pressure.
In order to properly select the correct gas regulator, it is recommended to consider the following points:

  • Type of gas (corrosive, toxic, neutral and inert as well as oxidizing gas)
    The regulator should be fitted with the type of used gas. For example, for oxygen gas, which is a flammable gas and quickly reacts with fat, the regulator must already be degreased and the effect of gas on the metal body of the regulatormust be considered for the corrosive gases.
  • The place of installing the regulator: Is the regulator installed on the cylinder either in the process line or on the manifold? Each of these cases affects the selection of the regulator.
  • Input pressure to regulator: It depends on the source pressure of the gas, and it must be proportional to it.
  • Output pressure: It depends on the consumer’s needs.
  • The number of pressure gauges and their accuracy: Often, 2 gauges are used on the regulator, one of which shows the input pressure and the  other shows the output pressure, and the gauge measurement range should normally be greater than the desired pressure.
  • The functionalaccuracy of the regulator at the output (single-stage, double-stage or the gas regulatorprecision): This depends on the consumer’s requirements.
  • Type of the regulator input and output connections: Input connections depend on the gas supply connections (if it is a cylinder, then it will depend on the type of valve) and the output connections depend on the consumer connections.
  • Regulator be equipped with relief valve controller
  • The possibility of purging to increase the safety and useful life of the regulator and the entire gas control system by a neutral gas such as nitrogen, especially when the gas used in the regulator is corrosive or toxic.
  • The operating environment temperature and gas control process
  • Type of regulator usage (industrial, laboratory and medical)
  • Regulator material: It Depends on the type of used gas. The following table shows the compatibility of the metals used in the gas regulator.


Pure gas Brass Stainless steel Aluminum Plated Brass
× × × Acetylene
× × × Helium
× × × × Argon
× × Hydrogen
× × × Ethylene
× × × Ethane
× × × × Nitrogen
× × × Oxygen
× × × Carbon Dioxide
× × Carbon Monoxide
× × × Methane
× × × × Air
× × × Propane
× × × Butane
× × Ammonia
× Arsine
× Chlorine
× × Krypton
× Nitric Oxide
× Phosphine

If needed special regulator for helium gas, oxygen gas, nitrogen gas, gaseous hydrogen, and so on,contact Tosse Gas Company

Contact Information:
Factory: Industrial Estate, Khomein, Markazi Province, Iran
Tel: 0098-8646485155
Fax: 0098-8646485129
Head Office: Unit 4, No 328, North Soheilian Street, Shahid Sani Street, Narmak, Tehran, Iran
Tel : 0098-2177696030
Fax : 0098-2177263975