Why choose a Single Acting Actuators?

By Martin Lissenburg, Product Specialist

Wednesday 26 April 2017

What is a single acting actuator or cylinder and why choose one? This article introduces single acting cylinders and advises when you should select single acting over double acting.


As the name suggests a single acting actuator, also known as a single acting cylinder, uses air (pneumatic pressure) to drive the piston rod in one direction only; the return action is achieved using a spring.

So, there are two possible rest positions for the actuator:

  • Sprung In, where the piston is fully retracted at rest; and
  • Sprung Out, where the piston rod is fully extended at rest.

Why choose a single acting cylinder over a double acting cylinder?

There are four principle reasons why a single acting cylinder can be a more effective and/or efficient option:

  • Fail safe - where safety may be a critical consideration, the single acting cylinder has a defined rest position in the event of a power failure
  • Resets to a known position - the known rest position also makes for an easier reset sequence
  • Consumes less air - because air is used in one direction only, there is less consumption compared to a double acting actuator; this gives optimum efficiency and lower operating cost.
  • Easier to control - finally, control is relatively simple using a 3/2 way pneumatic valve; air flow from port 1 to port 2 extends (sprung in) or retracts (sprung out) the piston rod and exhausting air from port 2 to port 3 allows the spring to return the piston rod to its rest position.
Why choose IMI Norgren actuators?

We offer a very comprehensive range of single acting cylinders, with roundline, compact, clamping, profile and tie-rod variants, many carried in-stock.

All carry the high-performance specification you'd expect from an IMI Norgren product; magnetic piston and adjustable cushioning as standard or available, a 2-year warranty and ISO 6432, ISO 21287 and ISO 15552 options.

What accessories are available?

We have a wide range of accessories available to ensure a complete system build. A comprehensive set of mountings; a full range of fittings and tubing for connection; reed switches to give position sensing and switching and service kits to allow maintenance


More information

Find out more by viewing some of our single acting actuator ranges.

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