`Catapult` actuator is at the heart of novel valve

A British company has developed a novel type of valve which could provide precise control of hydraulic and pneumatic systems, as well as other forms of fluid control. The device, called a "rolling-swing valve", is based on a catapult-like magnetic actuator technology invented by Wladyslaw Wygnanski, managing director of the Cambridge-based company, Camcon Technology.

Wygnanski has spent almost 20 years developing his "binary actuator" technology, which is based on a combination of permanent magnets and electromagnets. A sprung armature is held in one of two states by a magnetic field created by the permanent magnets. An electromagnet is positioned with its axis perpendicular to the direction of the armature movement and, when energised for a fraction of a second, disrupts the PM field, allowing the spring to move the armature.

The armature accelerates quickly through the magnetic field to the opposite pole where it slows to a standstill, recycling its energy through the spring. The actuator, which draws very little energy, can switch at speeds of up to 4kHz.

In the rolling-swing valve (shown above), the actuator opens and closes the valve with the whole armature rolling from one stable position to the other. No power is needed to hold the valve in either the open or closed positions.

The valve, which allows bidirectional flows, reacts in just 3ms, and requires less than one joule of energy for each changeover. A hardened roller attachment can be used to crush small particles in the fluid, thus avoiding the need for filters.