Valves for miniature applications
Original article date: October 1999
Hoerbiger-Origa has come up with a novel pneumatic valve that promises improved control and miniaturisation. Tommy Miller has been finding out
Following pioneering developments in piezo technology for pneumatic control, Hoerbiger-Origa (Interface) has made further advances in electro-pneumatic control. The new Megamic interface brings the benefits of silicon technology to the field of pneumatics and, in so doing, new levels of control and miniaturisation are now possible.
At the heart of the Megamic concept are Silicon electro-pneumatic micro-valves, which combine silicon technology with advanced actuation principles. With minute dimensions, low capacity electronic control and the highest degree of precision in a wide temperature range, the Megamic valves should be capable of fulfilling a variety of specialist applications.
Development of the actuation principle and construction of the Megamic silicon micro-valves were carried out in close co-operation with the Fraunhofer Institute and the Hahn-Schickard Institute for Micro and Information Technology.
The encapsulated silicon chip is actually a micro-valve, inside which a valve plate is moved by electrostatic attraction, and it is this that regulates the flow of gases. Various valve functions can be realised, such as 2/2 and 3/2-way valves, normally opened or closed. Electrostatic attraction allows the valve to be controlled with the smallest possible electrical current in a large temperature range.
Small amounts of air are regulated precisely, and this can be used for the full pressure range of pneumatic equipment, typically 0-16 bar. Additional components make this micro-valve more flexible for various flow rates and voltage ranges.
For automation technology, the micro-valve is combined with a pneumatic booster, resulting in a miniature valve only 10mm wide and with a nominal bore of 1.5mm. Given a suitable control circuit, the valve can be controlled with a TTL-peak signal. The miniature valve is ideally suited to miniature medical devices, analytical equipment, micro-assembly equipment and for piloting miniature conventional valves.
By utilising the silicon technology, further developments will enable the complete integration of sensors, control and communication electronics to facilitate the production of intelligent micro valves.
- Hoerbiger-Origa
October 1999