A VALVE-LESS PLANAR FLUID PUMP WITH 2 PUMP CHAMBERS

A new planar fluid pump based on the valve-less diffuser/nozzle pump principle is presented. The pump consists of two pump chambers, each with two flow rectifying diffuser/nozzle elements with rectangular cross sections, one at the inlet and one at the outlet. The pump chambers are arranged in parallel for high pump flow. Each pump chamber has two piezoelectrically vibrated diaphragms. The planar pump is fabricated in brass with a total thickness of 1 mm. The pump chamber diameter is 13 mm and the diffuser/nozzle element neck dimensions are 0.3x0.3 mm. Simplified theoretical analyses of the maximum pump flow and resonance frequency are given. The flow rectifying ability of the diffuser/nozzle elements is demonstrated in a stationary flow situation and the pump performance is verified in two different pump mode configurations: anti-phase and in-phase chamber volume excitation. The measurements in the anti-phase mode show pump flows and pump pressures which are more than 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 pressure of about 1.7 m H2O with the pump diaphragm vibration frequency set to the pump resonance frequency of 540 Hz.