A NEW MICROPUMP PRINCIPLE OF THE RECIPROCATING TYPE USING PYRAMIDIC MICRO FLOWCHANNELS AS PASSIVE VALVES

The working principle of a dynamic micropump is presented and its basic parameters are discussed. The dynamic micropump has a very simple and cheap structure consisting of a pump chamber, an oscillating membrane and two truncated pyramid shaped microchannels produced by anisotropic etching of silicon. The latter show a direction-dependent behaviour of their flow resistances, for which reason they provide as so-called dynamic passive valves; a partial rectifying of an alternating flux. The simple mechanical system of the micropump enables high working frequencies between 100 Hz and 10 kHz; the zero-load pump rate is equal to or higher than 250 mu l min(-1), being up to one order of magnitude more than the micropumps so far developed can provide. The pump parameters can be chosen in a wide range by simply changing the size of the dynamic valve channels.