Patent ID: 8323247

Claim:
An infusion device, comprising: a fluid transfer device including an external housing tube having an inner surface, an internal housing tube defining a piston lumen having a pump chamber, an outer surface having a perimeter, and a bypass aperture having an inlet associated with the pump chamber and an outlet adjacent to the outer surface and defining a bypass aperture longitudinal axis, at least a portion of the internal housing tube being located within the external housing tube such that at least a portion of the outer surface of the internal housing tube is proximate the inner surface of the external housing tube, a bypass channel in fluid communication with the bypass aperture outlet, a resilient valve member that extends around the perimeter of the internal housing tube outer surface and over the bypass aperture outlet, and a piston carried within the piston lumen and movable between a pull-back position where the pump chamber volume is maximized and a rest position where the pump chamber volume minimized, the piston defining a longitudinal axis that is transverse to the bypass aperture longitudinal axis, wherein the internal housing tube, resilient valve member and piston are configured and positioned relative to one another such that fluid is drawn into the pump chamber as the piston moves to the pull-back position and the fluid within the pump chamber is forced through the bypass aperture and past resilient valve member as the piston moves to the rest position; an infusion device outlet operably connected to the fluid transfer device; and a reservoir operably connected to the fluid transfer device such that the fluid transfer device receives fluid from the reservoir.