A gas regulator is an instrument used to control the delivery of gas at constant pressure. Gas regulators help to reduce the high pressure in the cylinder or process line to a lower usable level as it passes to other equipment such as a gas oven. A constant pressure is maintained within the gas delivery system. It does not affect the flow of the gas but controls the delivery pressure.
A gas regulator consists of three main components--a sensing element, control element and loading mechanism. These components help to reduce the pressure of the gas. Gas pressure regulators use springs for the loading mechanism. When the regulator knob is turned, the spring gets compressed. The force on the spring is communicated to the control and sensing element to achieve the pressure at the outlet. Sensing elements in gas regulators sense the force which is placed on the spring and set the delivery pressure.
Diaphragms are commonly used as sensing elements. These diaphragms are made of either metals or elastomers. The change in force is communicated by the sensing element to the control element. The control element in gas regulators is the value that assists to reduce the inlet pressure to outlet pressure.
The gas regulator has a principle of operation. When the gas regulator knob is turned, the loading mechanism gets compressed. The spring displaces the sensing element and the diaphragm pushed on the control element making it move away from the gas pressure regulator’s place, then the orifice becomes larger to provide the pressure and flow required.
There are four main types of gas pressure regulators--general purpose regulators, line gas pressure regulators, high purity gas pressure regulators and special service gas regulators. Line regulators are point of use gas regulators which are used for low-pressure pipelines. Line regulators are also used with high-pressure cylinder regulators that maintain the pressure between 250 to 400 psig (pound-force per square inch gauge).
Gas regulators are designed for longevity and economy. They have applications in pilot plant, noncorrosive plants and maintenance-shop applications. High-pressure gas regulators are designed to provide resistance and diffusion. Inboard diffusion is reduced or eliminated by the metal diaphragms, seals and high-purity seals. Special regulators are also available which are used in specific applications such as fluorine service, acetylene, oxygen, ultra-high pressure and corrosion service.
General Safety Warning
When installation and inspection are improper, the gas cylinders can cause accidents. The regulator should be protected from extreme weather conditions. In freezing climatic conditions, water can block the safety vent on the regulator by forming ice. The regulator then cannot control the gas pressure properly. Advise the appropriate authority immediately when there is a leak in the gas regulator or cylinder. Have the regulators checked periodically.