1. Normally closed microvalve for use in a microfluidic device comprising a valve seat, an outlet, an inlet and one or more flexible pre-compressed or pre-stretched separators, preferably the membranes with one or more flexible pre-compressed or pre-stretched separators are arranged so that the pre-compression or pre-tension forces one or more separators to the valve seat in a normally closed polozhenii.2. Normally closed microvalve according to claim. 1, characterized in that the separator is a membrane, and wherein said membrane is imperforate membranami.3. Normally closed microvalve according to Claim. 1 or 2, characterized in that it has one or more cavities, the channel body portion, a seal such as an O-ring, glue, flow regulator, for example a flow restrictor, a controller and ramu.4. Normally closed microvalve according to claim. 1, characterized in that it further comprises a body portion, wherein the valve seat has a width less than the width of one or more flexible pre-compressed or pre-stretched separators, and each of the separators has an area that is larger than the saddle klapana.5. Normally closed microvalve according to claim. 4, wherein the microvalve further comprises means for sealingly attaching the body portion to the area of each of the one or more flexible pre-compressed or pre-stretched separators larger than the valve seat, preferably wherein the means for sealingly attaching a double-sided adhesive tapes1. Нормально закрытый микроклапан для применения в микрофлюидном устройстве, содержащий седло клапана, выпускное отверстие, впускное отверстие и один или более гибких предварительно сжатых или предварительно растянутых сепараторов, предпочтительно мембран, при этом один или более гибких предварительно сжатых или предварительно растянутых сепараторов расположены так, что предварительное сжатие или предварительное растяжение прижимает один или более сепараторов к седлу клапана в нормально закрытом положении.2. Нормально закрытый микроклапан
