Abstract: A fluid pump device for use in conjunction with a tubular pumping chamber which is composed of an elastic material and which has a pair of spaced-apart unidirectional valves through which fluid can be passed with cyclic compression and expansion of the chamber. The pump device is intended for medical or veterinary applications and it comprises spaced-apart clamp elements between which the pumping chamber can be removably located, an electrically actuated solenoid device for effecting cyclic relative movement of the clamp elements whereby cyclic changes in the contained volume of the pumping chamber are induced when the chamber is located between the clamp elements, and electrical circuitry associated with the solenoid for energizing the solenoid at a selectable repetition rate.

Abstract: A medical infusion pump for use in conjunction with a valved elastomeric pumping chamber. The pump comprises a pair of clamp elements between which the pumping chamber is located and one of the clamp elements is movable relative to the other to effect cyclic compression and expansion of the pumping chamber. The movable clamp element is constituted by an extension of a solenoid armature and such clamp element moves in a direction away from the fixed clamp element, to permit expansion of the pumping chamber, when the solenoid is energized. A compression spring acts against the solenoid armature and serves to bias the movable clamp element in a closing direction when the solenoid is de-energized, whereby a compressive force is applied to the pumping chamber. An electric motor is coupled to the spring by way of a motion translating mechanism and, when energized, the motor functions to change the effective length of the spring and, hence, the biasing force exerted on the movable clamp element.

Abstract: A fluid pump for location within a reservoir and which is operable with rise and fall of liquid within the reservoir. The pump comprises a tube of a resiliently deformable material, an abutment surface which is engaged by the tube and a float device which is mounted to the tube. Liquid entering the reservoir causes upward movement of the float device and such movement of the float device causes increasing engagement between the tube and the abutment surface. The increasing engagement between the tube and the abutment surface causes the tube to deform resiliently and a localized reduction in the contained volume of the tube is thereby effected to cause expulsion of fluid from the tube. Conversely, as the liquid level falls in the reservoir, the float device moves downwardly to reduce the extent of engagement between the tube and the abutment surface, so that the tube tends to resume its initial contained volume.