In brief
A pressure regulator, also called a pressure reducing valve, lowers a fluctuating inlet pressure to an adjustable outlet pressure that is kept as constant as possible.
Contents
What is Pressure regulator?
Pressure regulators ensure that consumers are supplied at the pressure appropriate for them, regardless of fluctuations in the network. In compressed air systems they supply cylinders, tools and valve terminals; in process engineering they regulate gases, water or steam. A lower working pressure saves energy and protects components.
In the common spring-loaded design, the set spring force acts against the outlet pressure on a diaphragm or piston. If the outlet pressure falls, the valve opens further; if it rises, the valve closes. Relieving regulators automatically vent excessive outlet pressure. Precision regulators work with minimal deviation, while electronic proportional pressure regulators set the pressure via an electrical setpoint signal. Key parameters are inlet pressure, adjustment range, flow rate, connection size, medium and materials.
Faults show up as fluctuating outlet pressure or outlet pressure that creeps upwards. Causes include dirty valve seats, aged diaphragms and seals or a regulator that is too small for the flow rate. In maintenance, it pays to document set pressures and secure them against unauthorised adjustment. A regulator set too high increases energy consumption and wear; one set too low leads to malfunctions.
In practice: maintenance and procurement
For a replacement, the medium, inlet pressure, adjustment range, flow rate, connection thread and required functions such as relieving or a gauge port must be known. Regulators in gas or steam systems are also subject to the requirements of the respective installation.
Synonyms and abbreviations: pressure reducer · pressure reducing valve (PRV) · pressure reducing regulator · air regulator
Frequently asked questions
What is the difference between a pressure regulator and a pressure relief valve?
A pressure regulator lowers a higher inlet pressure to a lower, constant outlet pressure and is open during operation. A pressure relief valve is closed in normal operation and only opens when the pressure reaches a limit, in order to reduce it. The regulator therefore supplies consumers, while the relief valve protects the system.
What does relieving mean for a pressure regulator?
A relieving regulator can itself reduce excess pressure on the outlet side, for example when the setpoint is lowered or a reaction from the consumer increases the pressure. The air escapes via a vent port. Without this function, the higher pressure remains until a consumer draws off air.
What information is needed to replace a pressure regulator?
Important are the medium, maximum inlet pressure, required adjustment range, required flow rate, connection thread, materials, temperature range and additional functions such as relieving, a pressure gauge or a lockable adjusting knob. For electronic regulators, the setpoint signal and supply voltage are also needed. The nameplate and type designation provide most of the data.
Why does the outlet pressure at the pressure regulator rise slowly?
A creeping rise in pressure usually indicates that the valve no longer closes tightly, for example due to dirt on the valve seat or a worn valve disc. A damaged diaphragm can also cause this behaviour. Cleaning or a repair kit often solves the problem; upstream filters help prevent it.