The invention relates to a valve, particularly for a structural element of microfluid technology, with valve bodies having surfaces for mutual contact which are moveable relative to each other, so as to displace the contact surfaces, wherein ducts end in one of the contact surfaces for the inflow and outflow of a fluid and an indentation for the formation of a connection between the ducts is provided in the other contact surface.
Miniaturized valves of this type which can be used for flow control in microfluid technology are known from, for example, DE 102 27 593 B4 and U.S. Pat. No. 6,748,975 B2. The contact surfaces of the valve bodies of these known valves carry out a double function. On the one hand, they seal the inlet duct relative to the outlet duct when the valve is closed. On the other hand, they ensure that the valve is sealed relative to the surroundings in any position of the valve. The latter function is of particular importance, because fluid-technological microelements, in particular flow cells, are primarily used for examining substances which burden the environment, for example, substances containing pathogenic germs.
The manufacture of the contact surfaces in the quality necessary for the sealing function is very difficult. In addition, numerous requirements, among them the suitability for friction pairing, limit the possibilities of material selection. Elastic synthetic materials, which are usually suitable for sealing, which however contain softeners, usually do not qualify. In the same manner, in most cases the use of lubricants for supporting the sealing function is not permissible. For example, in the case of long-term use of the valves which impairs the sealing function of the contact surfaces there is the danger of environmental contamination.
In addition, in accordance with the prior art, a moveable valve body for securing the sealing function relative to the surroundings/environment must always rest against the wetted sealing surface and, thus, connected tightly with a structural component which processes the fluid. This is particularly disadvantageous if the structural component processing the fluid is a disposable article. Particularly in the case of several valves per disposable, the manufacture of the moveable valve body itself and for its fluid-tight mounting, for example, at a flow cell, becomes significantly more difficult.