Compact actuator delivers high torque with low air consumption

August 2002 Valves, Actuators & Pump Control

The compact pneumatic quarter turn actuator, supplied by Dupleix Liquid Meters (DLM), has been developed to be simple, reliable, and efficient using a patented rack and pinion design. Four separate racks, each with its own piston, develop torque around the centrally located pinion.

This four-piston design permits air pressure to be applied to four racks simultaneously, significantly increasing torque, and thus reducing the actuator's overall size compared to single and double piston designs.

Symmetrically spaced at 90° angles around the central pinion, the Compact's four piston/racks also achieve a more uniform load distribution than do single and double rack actuators, greatly reducing gear wear at the points of contact between rack and pinion.

A look at the operation of the Compact actuator reveals several other important advantages of its symmetrical four piston design, including a trouble-free high cycle life, minimum air consumption, energy efficiency, fast response, and of course, a compact size.

The corrosion resistant, anodised coating of the body, covers and stop provides protection internally and externally, and a two-layer external polyurethane paint coating provides protection against aggressive environments. The stop design allows rotational adjustment in both directions of actuator travel. The 'Safe Guard' design ensures secure operation, assembly and disassembly of the actuator.

Compact's superiority over single and double rack designs is achieved through distribution of the total torque equally among its four piston and racks, so that each rack generates less torque. At a given air pressure, Compact can produce the same torque output using smaller diameter pistons and a narrower pinion. Four small cylinders, each located on one side of a cube, results in a compact, space saving shape.

Four pistons result in a shorter piston travel, which is what is responsible for Compact's fast acting operation. The device's cube shape and short piston travel minimise dead space. Dead space is space not swept by piston travel that must be pressurised before piston motion begins. This is pressurised air that does no work but nonetheless requires energy to maintain pressure. This minimum dead space geometry is what results in minimum air consumption, which in turn means improved energy efficiency, since little pressurised air goes to waste.

For more information: Marc von Ruben, DLM, 011 457 0500, [email protected], www.dlm.co.za

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Valves, Actuators & Pump Control

Compact actuator delivers high torque with low air consumption

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