Valves and valve actuation – Electrically actuated valve – Having element dimensionally responsive to field
Patent
1998-01-28
1999-12-14
Rivell, John
Valves and valve actuation
Electrically actuated valve
Having element dimensionally responsive to field
251331, 25112901, F16K 3102
Patent
active
060006765
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The present invention refers to valves for controlling fluid flows and especially to valves in which the distance between a valve plate and a valve opening is only very small.
DESCRIPTION OF THE PRIOR ART
A valve to which the present invention can be applied is e.g. an electrostatically driven microvalve of the type shown in FIG. 1. An electrostatically driven microvalve consists of a valve body 10 provided with a valve opening 12 and a valve plate 14 with fluid openings 16. The valve opening has typically a square shape, the square having a side length of 0.2 mm. The valve opening 12 is surrounded by a sealing edge 18 extending along the circumference of the valve opening 12. The sealing edge 18 can be formed e.g. by a raised portion along the circumference of the valve opening.
The valve plate 14 and the valve body 10 are arranged such that they are movable relative to one another in such a way that the valve opening 12 of the valve body 10 can be closed and opened by means of the valve plate 14. This arrangement can either be of such a nature that the valve body is arranged fixedly and the valve plate elastically or it can be of such a nature that the valve body is arranged elastically and the valve plate fixedly. In the example of a known electrostatically driven microvalve shown in FIG. 1, the valve plate 14 is secured to the valve body by means of a spacing layer 20 and has portions of reduced width 28 (cf. FIG. 2) therein. This has the effect that the central part of the valve plate 14 is elastically suspended relative to the valve body 10. In the voltage-free or pressureless condition, the valve plate 14 is located some micrometers (typically 5 micrometers) away from the valve body, and the valve opening 12 is consequently open. Such a valve is referred to as normally-open arrangement.
The valve body 10 and the valve plate 14 are enclosed in a housing 22. The housing has two openings 24a, 24b which can respectively serve as an inlet or as an outlet.
The valve is actuated by the application of an electric voltage U between the valve body and the valve plate. When this voltage is applied, charges flow onto the opposed sides of the two components. These charges attract each other, whereby the valve plate as a whole is moved towards the valve body. In order to prevent an electric short circuit when the valve plate 14 and the sealing edge 18 of the valve body 10 are in contact with each other, an insulating layer 26 (shown only for the valve plate 14) is applied to one component or to both components. In a valve for controlling fluid flows, the valve opening and the valve body must be surrounded completely by an insulating layer so as to insulate these two components.
Due to the electrostatic drive principle, such a microvalve shows a very small distance between the valve plate and the valve body. This small distance between the valve plate and the valve body limits the volumetric flow rate through the valve.
EP-A-0435237 discloses an electronic microvalve, the structural design of which aims at obtaining a minimized actuating voltage, a minimized actuating energy for the closing plate of the valve and good closing properties. This known microvalve has a square valve opening which is adapted to be closed by means of a closing plate that can be moved perpendicularly to the opening. For achieving the above-mentioned advantages, the known microvalve is formed of an integral structure.
SUMMARY OF THE INVENTION
It is a principal object of the present invention to provide a microvalve having an increased flow rate, without influencing the pressure dependence and the actuating voltage of said microvalve.
This object is achieved by a microvalve for controlling a fluid flow, said microvalve comprising:
a valve body provided with a valve opening having a sealing edge, and
a valve plate provided with fluid openings, said valve plate being adapted to be moved perpendicularly to the valve body in such a way that, at a first position, said valve plate closes the valve opening, whereas, a
REFERENCES:
patent: 4585209 (1986-04-01), Aine et al.
patent: 4654676 (1987-03-01), Itano et al.
patent: 5323999 (1994-06-01), Bonne et al.
patent: 5333831 (1994-08-01), Barth et al.
patent: 5400824 (1995-03-01), Gschwendtner et al.
patent: 5785295 (1998-07-01), Tsai
patent: 5897097 (1999-04-01), Biegelsen et al.
Frisch Herbert
Wirtl Johannes
Zengerle Roland
Hygrama AG
Rivell John
Schoenfeld Meredith
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