A VALVE-LESS PLANAR FLUID PUMP WITH 2 PUMP CHAMBERS

A new planar fluid pump based on the valve-less diffuser/nozzle pump p rinciple is presented. The pump consists of two pump chambers, each wi th two flow rectifying diffuser/nozzle elements with rectangular cross sections, one at the inlet and one at the outlet. The pump chambers a re arranged in parallel for high pump flow. Each pump chamber has two piezoelectrically vibrated diaphragms. The planar pump is fabricated i n brass with a total thickness of 1 mm. The pump chamber diameter is 1 3 mm and the diffuser/nozzle element neck dimensions are 0.3x0.3 mm. S implified theoretical analyses of the maximum pump flow and resonance frequency are given. The flow rectifying ability of the diffuser/nozzl e elements is demonstrated in a stationary flow situation and the pump performance is verified in two different pump mode configurations: an ti-phase and in-phase chamber volume excitation. The measurements in t he anti-phase mode show pump flows and pump pressures which are more t han twice as high as those of the in-phase oscillation mode. The anti- phase mode has a pump capacity of about 16 ml/min and a maximum pump p ressure of about 1.7 m H2O with the pump diaphragm vibration frequency set to the pump resonance frequency of 540 Hz.