A PUMP AND A FLUID DISPENSING DEVICE INCORPORATING A PUMP

摘要

A pump (2) for use in an implantable drug delivery system for ambulatory patients meets the requirement for small size by comprising a piezoelectric disc element bonded to a diaphragm member forming one wall of a pump chamber (18), and a battery (26) and electrical circuits (22) for cyclically applying electrical voltage to the piezoelectric member whereby to induce pumping movement in the diaphragm member to pump drugs from a reservoir (12) via a valve (14) to a delivery catheter (20) via a valve (16). A gas spring (30) is provided to move the pump (18) to maintain adequate pressure in the drug reservoir.