Gas pressure regulators reduce high-pressure gas in a cylinder or process line to a lower, usable level as it passes to another piece of equipment. They also maintain pressure within a gas delivery system. Gas pressure regulators are not flow control devices; they are used to control delivery pressure only.
Video Credit: Swagelok Company
There are three basic operating components in gas pressure regulators: a loading mechanism, a sensing element, and a control element. These three components work together to accomplish pressure reduction.
Loading mechanisms for gas pressure regulators determine the setting of the regulator delivery pressure. Most gas pressure regulators use a spring for the loading mechanism. When a gas pressure regulator’s hand knob is turned, the spring is compressed. Force is placed on the spring and is communicated to both the sensing element and the control element to achieve the outlet pressure.
Sensing elements in gas pressure regulators sense the force placed on the spring and set the delivery pressure. Most gas pressure regulators use a diaphragm as the sensing element. These diaphragms may be constructed of elastomers or metal. The sensing element communicates this change in force to the control element.
In gas pressure regulators, the control element is the valve that accomplishes the reduction of inlet pressure to outlet pressure. When the gas regulator’s hand knob is turned, the loading mechanism is compressed. The spring displaces the sensing element and the diaphragm then pushes on the control element, causing it to move away from the gas pressure regulator’s seat. In turn, the orifice becomes larger in order to provide the flow and pressure required.
There are four main types of gas pressure regulators including:
Line gas pressure regulators - Typically, line regulators are point-of-use gas pressure regulators that serve low-pressure pipelines. They can be used in conjunction with high-pressure cylinder regulators that limit the inlet pressure to 250 to 400 psig.
General-purpose gas pressure regulators - Designed for economy and longevity. They are recommended for noncorrosive general plant, pilot plant, and maintenance shop applications.
High-purity gas pressure regulators - Designed and constructed to provide diffusion, resistance, and easy cleanup. In these types of gas pressure regulators, inboard diffusion is minimized or eliminated by metal diaphragms and high-purity seats and seals.
Special service gas pressure regulators - A type of gas pressure regulators specifically constructed for specialized applications including oxygen, acetylene and fluorine service, high-pressure, ultra high-pressure, and corrosion service. Additional custom gas pressure regulators are available.
BS EN 334 - Gas pressure regulators for inlet pressures up to 100 bar
BS EN ISO 10524-1 - Pressure regulators for use with medical gases
CGA E-4 - Standard for gas pressure regulators
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