A Valve-less Planar Pump In Silicon

A planar double chamber pump fabricated in silicon anodically bonded to glass and based on the diffuser/nozzle pump principle is presented. The diffuser/nozzle elements have a depth of 24 - 48 /spl mu/m and a neck width of 88 - 104/spl mu/m. The pump chamber diameter is 6 mm. Pump cavities and diffuser/nozzle elements are etched with an isotropic HNA-etch in the silicon. Pumps with three different diffuser lengths are compared reaching a maximum pump capacity of 230 /spl mu/min and a maximum pump pressure of 1.7 in H20 at a resonance frequency of 1318 Hz for methanol.