Introduction to Air Regulators
Air Regulator Types
Regulator Size
Pressure Range
Flow Capacity
Maximum Supply Pressure
Minimum Regulated Pressure
Sensitivity
Exhaust Capacity
Self-Relieving Regulators
Air Consumption
Regulator Mounting
Introduction to Air Regulators
Air regulators provide a convenient method of reducing a supplied compressed air pressure to a desired constant lower pressure. Reduced air pressure is highly desirable for energy conservation, safety requirements, improved air actuator control, controlling force or torque, industrial processes, and air instrumentation. The desired secondary pressure is generally set by turning an adjustment knob or screw located on the regulator or by use of a pilot signal in the case of relays/boosters. Standard self-relieving regulators will vent any excess pressure, above the set point, that may build-up down stream of the regulator. The ability of an air regulator to control changes in supply pressure, flow, and ambient temperature often determine the regulator required for a specific application. Air regulators are generally selected by required accuracy, pipe size, flow rate, pressure range, and maximum inlet pressure.
Air Regulator Types
Precision Air Regulators – Precision regulators provide the highest degree of accuracy, repeatability, precision control, and flow/pressure stability under the most adverse operating conditions. Some precision regulators will control air pressure with an accuracy of 0.1%. Precision regulators will provide much better control in lower pressure applications.
General Purpose Air Regulators - General purpose regulators are used to provide a low cost method of reducing a supplied compressed air pressure to a relatively constant reduced air pressure. These regulators work well in many applications where a precision regulator is not required.
Miniature Air Regulators – Miniature regulators are ideal choices where a small, compact unit is required to reduce a supply pressure to a relatively constant reduced secondary air pressure. These regulators work well in low flow applications where a precision regulator is not required.
Air Filter/Regulators – Often called piggyback filter/regulators, these units combine an air pressure regulator and a filter into an integral housing with a common inlet and a common outlet. This saves on space, set-up time and piping costs. The air filter is designed to remove from the air any rust, scale, condensed water and other debris which may cause wear and premature failure of air tools, valves, cylinders and other pneumatic equipment.
Air Relays/Boosters – These regulators use a pilot pressure signal to control the secondary output pressure rather than the conventional manual adjustment knob. The pilot signal is typically from a remote pilot regulator, electro pneumatic regulator or pressure transducer. Relay/Boosters are often used to increase the required flow capacity.
Regulator Size
Regulators are available in many sizes from compact miniature units to heavy-duty high flow units. Generally, larger port sizes will provide higher air flows. Factors to consider when selecting a regulator size include physical overall size, flow capacity, and the actual pipe port size.
Pressure Range
The output secondary pressure from an adjustable air regulator can be set anywhere within its pressure range. This adjustment is usually made using an adjustment knob, screw or from a remote pilot signal, in the case of a relay/booster. Manually adjustable regulators generally offer a locking nut or knob to help prevent pressure changes. Most regulators will not operate properly below their published minimum pressure, consider using precision regulators for controlling pressures less than 10-15 PSI.
Flow Capacity
The amount of compressed air, measured in SCFM (standard cubic feet per minute), capable of passing through the regulator based on a specific inlet and outlet pressure.
Maximum Supply Pressure
The maximum allowable pressure supplied to the inlet port of the regulator. Supply pressure variation is the amount of change in outlet pressure with regard to changes in the inlet pressure.
Minimum Regulated Pressure
Most regulators will not operate properly below the minimum pressure range listed in the specifications. Consider using precision regulators for low pressure applications less than 10-15 PSI.
Sensitivity
A measure of how precise the output pressure of a regulator can be set. Sensitivity is typically measured in inches of water column. Precision regulators are the most sensitive regulators and typically use a unique rolling diaphragm design.
Exhaust Capacity
The exhaust capacity of a regulator is the ability of the regulator to relieve (vent) down stream pressure back through the outlet port and vent in the regulator body. Some regulators offer an extra high exhaust flow for applications where excessive reverse flow is required.
Self-Relieving Regulators
Self-relieving regulators have the ability to relieve or exhaust excess down stream pressure back through the regulator body, if outlet pressure should increase above the set pressure. A non-relieving regulator does not have the ability to relieve this down stream pressure.
Air Consumption
The amount of air that a regulator consumes during regulation, this includes bleed, seat leakage or any external leakage. Normally, the more accurate regulators incorporate a very small bleed to provide improved accuracy and superior performance when compared to most general purpose regulators.
Regulator Mounting
Regulators can be mounted by in-line pipe using the threaded inlet and outlet ports,
wall mounted using existing mounting holes in the regulator body or with an “L” bracket, panel mounted, or modular mounted. Many regulators also offer a female NPT port for installing a pressure gauge, used for reading the outlet set point pressure.
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