Terminology Explained - Proportional Valves

By Martin Lissenburg, Product Specialist

For many, engineered products terminology can sometimes be a barrier to considering the use of the product in a design.

This article sets out to address this issue for proportional valves. Whilst some terms seem self-explanatory, we will give more detail to ensure the meaning is clear.

What is a proportional valve?

A proportional valve provides a change in output pressure or flow in the same ratio as the change in the input; for example, if the input doubles then the output will also double.

Are proportional valves known by any other names?

The terms I/P and E/P Valves can be seen; this relates to current, I (4 to 20mA) or Voltage, E (0 to 5V or 0 to 10V), being used as the input supply to the coil which, ultimately,  gives the output pressure control.

What are the typical applications and types of proportional valves?

Static or dynamic applications are quoted:

  • A static application is one where the required output pressure remains fixed for virtually the complete time of the application
  • A dynamic application has a requirement for a continually changing output pressure during the application

There are various types of operation:

  • Directly operated - the coil acts directly on the spool or piston to adjust the valve position and control output pressure
  • Air pilot operated - air pressure is varied in a chamber to move a diaphragm; this, in turn, acts on the valve spool or piston
  • Piezo-electric operated - the crystal is deformed by application of voltage; this alters the piston or spool position.
What are the typical working applications of a proportional valve?

There are numerous applications where a Proportional Valve offers an ideal solution; some are given here:

  • Bottle Filling - the proportional valve maintains a constant pressure in the filling reservoir, irrespective of the liquid level; a pressure sensor in the reservoir provides feedback to the proportional valve. This ensures a constant volume of liquid is transferred to a bottle in a given time.
  • Furnace Control - the gas supply is regulated by the proportional valve; a differential temperature signal is used as feedback to shut down gas flow when the desired temperature is reached.
  • Leak Testing - the proportional valve can apply increasing pressure, at a defined profile, to a given test piece.

More information

Find out more by viewing our range of proportional valves.

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