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Valve transfers no heat to fluid
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09/12/2003
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Asco has introduced what is calls a 'Piezotronic' proportional valve for medical and analytical applications where it is imperative that no heat transfer takes place from the valve to the fluid.
The valves use CMA (Ceramic Multilayer Actuator) technology, which gives response times as low as 100 microseconds, a service life of more than 1billion cycles, and a power consumption of 0.3mA at 24v (0.007W) and 0.9mA at 70V. This means that there is no heat transfer from the valve into the fluid being controlled and the device is ideal for portable battery or even solar powered applications.
The CMA technology comprises a monolithic piezo-ceramic strip with integrated electrodes that are specially configured so that the element “bends” when a voltage between 20v and 40v is applied. This bending action, which involves no moving parts, is key to providing the precise levels of proportional control demanded in applications such as gas analysis and the micro-injection of aqueous solutions into living cells.
Furthermore, there are no inductive peaks when switching, so unlike conventional solenoid valves, no circuit protection is necessary. No holding current is required for the valves to maintain position, so heat generation here is not a problem either.
Asco is offering the valve with nominal orifice sizes of 0.6mm and 0.8mm, for flow rates up to 6 litres/min. In addition to the standard valve an intrinsically safe variant is available, rated EEx ia 11c T6, for use in potentially explosive atmospheres. TS
Asco Joucomatic
Pointers
* Response times are as short as 100 microseconds
* Nominal orifice sizes are 0.6mm or 0.8mm, for flow rates up to 6 litres/min.
* Service life is more than 1billion cycles, and a power consumption, 0.3mA at 24v (0.007W) and 0.9mA at 70V.
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Author
Tom Shelley
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