Fluid power maintains thrust of development
Fluid power developments continue to build on British innovation, despite the relative maturity of the technology, writes Tom Shelley
The UK, which built its industrial revolution on steam, continues to come up with radical developments in fluid power.
This reflects the fundamental nature of the technology, and continued room for efficiency improvements, despite the massive variety of excellent products offered on fast delivery by the likes of Bosch Rexroth, Festo and SMC.
The microprocessor controlled hydraulic/pneumatic prosthetic knee joint described by Dr Saeed Zahedi of PDD in our December 2001 edition was launched in 2002. Chas Blatchford describes it as, "The most advanced innovation in hydraulic knee control for over thirty years." PDD has since gone from strength to strength. In May 2003, the company received the Red Dot Special Prize for Intelligent Design for the Olympia Soundbug and the Red Dot Design Award for the Pogle Evolution. The Soundbug turns any hard surface into an effective soundboard for music or voice and the Pogle Evolution is said to be the world's most advanced digital film post-production controller.
The bi-stable, very fast switching valves developed by Wladyslaw Wygnanski and his colleagues at Cambridge-based Camcon Technology continue to make progress. Since the basic design concepts were described in some detail in our February 2002 edition, Camcon won a £45,000 DTI Smart Award in April 2003 to undertake a study into the feasibility of introducing high frequency modulation into the incoming fuel stream in gas and liquid-fueled turbines. The idea is to run turbines in lean burn mode, but use advanced control to suppress incipient instability perturbations before they grow sufficiently to damage the flame chambers. In May, the company announced that a pair of the company's binary actuators had completed more than 11.5 billion operations in laboratory tests. Each actuator had been performing 526 changeovers per second.
The latest idea to emerge from Camcon is a rolling swing valve. A 2ms electrical pulse to an electromagnet disrupts the magnetic field from permanent magnets so that the spring armature rolls from one stable position to another. Reaction time is less than 3ms, less than 1J of energy is required for the changeover, and no current is required to maintain either of the two stable positions. The roller is able to crush small solid particles and the valve is suitable for unfiltered fluids.
The Pursuit Dynamics steam ejector pump described in our December 2002 edition also continues to make progress. John Heathcote, the company CEO writes, "We announced at the end of January that we have two units undergoing evaluation with Sonico, a joint venture company between WS Atkins and an Anglia Water Group subsidiary, Purac. We commenced formal marketing of our PDX System last month and have been overwhelmed by enquiries from a large number of companies. As a result of this, we are taking on more personnel to deal with the licensing and business development aspects of our business."
Steam lives! as does the rest of the £900 million per year UK fluid power business.
* Fluid power development in the UK are alive and well
* Valves can switch more than 500 times per second using less power
* New developments include those based on steam, the foundation of the UK's original industrial revolution
Chas Blatchford & Sons
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