Abstract: A rechargeable infusate pump for implantation in the human body can be refilled periodically by injection through an inlet septum under the skin. A conduit from the pump outlet conducts fluid to an infusion site in the body. The needle penetrating the septum protrudes into an antechamber and discharges fluid and any foreign matter is trapped in the antechamber so that it cannot enter the pump chamber and possibly clog the pump outlet. This foreign material is removed by injecting a needle into the antechamber and drawing a vacuum to suck out the debris.The pump also has a special ring-like outlet filter in the fluid stream between the pump chamber and its outlet to provide a maximum amount of filter area in a minimum amount of space and the pump outlet includes a special flow controller which is able to very accurately meter the infusate to the selected body site.