Patent ID: 8196781

Claim:
A pump for use with a fluid reservoir, comprising: a) a hollow pump body comprising flexible walls having an inner surface and an outer surface, a first end for connecting to the reservoir and a second end for dispensing liquid, b) a top-cap sealed to the first end of the pump body, having at least one through hole for passage of fluid from the reservoir into the pump body; c) a nozzle sealed to the second end of the pump body, having at least one through hole for passage of fluid out from the pump body; d) a seal-base located between the nozzle and the top-cap, having a central seal-base opening, the seal-base dividing the pump body into an upper chamber between the seal-base and the top-cap and a lower chamber between the seal-base and the nozzle; e) a rigid seal-rod extending along an axis of the pump body from the top-cap to the nozzle through the seal-base opening, having a seal-head for sealing the opening in the seal-base by sealing against a side of the seal-base; the seal-base being movable from a first position in which the seal-head is sealed against a side of the seal-base, blocking flow of liquid through the opening in the seal-base, to a second position in which the seal-head is not in contact with the seal-base, allowing flow of liquid through the opening in the seal-base; the flexible walls surrounding the upper chamber being held in a stretched condition by the seal-rod, creating a restoring force between the top-cap and the seal-head; and the flexible walls surrounding the lower chamber being held in a stretched condition by the seal-rod, creating a restoring force between the seal-head and the nozzle; the restoring force of the flexible walls surrounding the lower chamber and the restoring force of the flexible walls surrounding the upper chamber, being selected to create a net restoring force pulling the seal-base into the first position and pressing the seal-head into the opening in the seal-base, sealing the seal-base opening and isolating the upper chamber from the lower chamber; such that when the seal-base is reciprocally moved parallel to the axis of the pump body, the seal-base is moved between the first position and the second position.