Disc pump and valve structure

A pump comprising:

• a pump body having a substantially elliptically shaped side wall having an internal radius (r) and closed by two end walls for containing fluids;
• an actuator formed by an internal plate having a radius greater than or equal to 0.63(r) and a piezoelectric plate operatively associated with a central portion of the internal plate and adapted to cause an oscillatory motion at a frequency (f) thereby generating radial pressure oscillations of the fluid within the pump body;
• an isolator having an inside perimeter coupled to a perimeter portion of the internal plate and an outside perimeter flexibly coupled to the side wall such that the actuator and the isolator form two cavities having a height (h) within the pump body, wherein the ratio of the internal radius (r) to the height (h) is greater than about 1.2;
• a first aperture positioned near a center of and extending through said actuator to enable the fluid to flow from one cavity to the other cavity;
• a first valve disposed in said first aperture to control the flow of fluid through said first aperture;
• a second aperture positioned near a center of and extending through a first one of the end walls to enable the fluid to flow through the cavity adjacent the first one of the end walls;
• a second valve disposed in said second aperture to control the flow of fluid through said second aperture;
• a third aperture positioned near a center of and extending through a second one of the end walls to enable the fluid to flow through the cavity adjacent the second one of the end walls;
• and
• a third valve disposed in said third aperture to control the flow of fluid through said third aperture when in use.