Patent ID: 6042345
Filing Date: 2000-03-28
Classification: F04B

Abstract:
A pump, comprising:a pump housing surrounding a pump housing interior;a first deformable member, said first deformable member being disposed within said pump housing interior;wherein said first deformable member comprises a first piezoelectric layer, said first piezoelectric layer having opposing first and second major faces;wherein said first deformable member further comprises a first pre-stress layer, said first pre-stress layer being bonded to said first major face of said first piezoelectric layer;wherein said first pre-stress layer normally applies a compressive force to said first piezoelectric layer;wherein said first deformable member partially encloses a variable volume pump chamber;and wherein said pump housing partially encloses said variable volume pump chamber;a second deformable member, said second deformable member being disposed within said pump housing interior;wherein said second deformable member comprises a second piezoelectric layer, said second piezoelectric layer having opposing first and second major faces;wherein said second deformable member further comprises a second pre-stress layer, said second pre-stress layer being bonded to said first major face of said second piezoelectric layer;wherein said second pre-stress layer normally applies a compressive force to said second piezoelectric layer;and wherein said second deformable member partially encloses said variable volume pump chamber;a first port in said pump housing communicating said variable volume pump chamber with the exterior of said pump housing;a second port in said pump housing communicating said variable volume pump chamber with the exterior of said pump housing;valving means in communication with said first port for temporarily opening and closing said first port;and energizing means in communication with said first piezoelectric layer and said second piezoelectric layer for electrically energizing said first piezoelectric layer and said second piezoelectric layer;wherein said energizing means comprises means for applying a first alternating voltage difference at a first frequency between said first major face of said first piezoelectric layer and said second major face of said first piezoelectric layer;and wherein said energizing means further comprises means for applying a second alternating voltage difference at a second frequency between said first major face of said second piezoelectric layer and said second major face of said second piezoelectric layer.