Pump apparatus and method including double activation pump apparatus
AssigneePharmacia Deltec, Inc.
InventorJames M. Olsen
Life of this patent
Estimating the term…
Abstract
A drug pump is disclosed having at least one rotatable cam and a reciprocally mounted follower engaged with the cam, and a tube which is compressed by the follower during rotation of the cam. The drug pump preferably has three followers, including an expulsor follower, an inlet valve follower, and an outlet valve follower. Three cams are provided to reciprocally move the followers, with one cam engaging each follower. The cams are interconnected by a cam shaft. The drug pump is ambulatory and provides two activations per revolution of the cams. The tube loading is nonlinear. Such nonlinear tube loading is taken into consideration to minimize energy consumption and to reduce peak torque loads. A design optimization and manufacturing system is provided to optimize energy consumption of the pump.
Claims7
A pump apparatus comprising:
- a rotatably mounted camshaft having a first cam having a cam surface, the camshaft having an axis of rotation, the cam surface of the first cam defining two lobes;
- a compressible tube;
- a reciprocally mounted first follower having a follower surface engageable with the cam surface of the first cam, the first follower including a tube surface engageable with the tube, the first follower being reciprocally movable in response to rotation of the first cam to compress the tube, the tube exerting a non-linear tube load on the tube surface of the first follower during rotation of the first cam;
- wherein the follower surface of the first follower has a convex shape relative to the axis of rotation;
- wherein the cam surface of the first cam has a shape which minimizes the energy consumed in rotating the first cam a predetermined amount based on the non-linear tube load, the energy consumed being directly related to the tube load, and wherein the shape of the cam surface of the first cam minimizes the maximum torque applied to the cam in rotating the first cam the predetermined amount based on the non-linear tube load, the maximum torque being directly related to the tube load;
- wherein the cam surface of the first cam has an irregular shape which provides the lowest energy consumed requirements and the lowest maximum torques for the non-linear tube load property;
- and
- wherein the camshaft is rotatable 180.degree. to complete one activation of the pump apparatus to pump fluid through the tube.
A pump apparatus comprising:
- a pressure plate;
- a compressible tube;
- a rotatably mounted cam shaft having a rotation axis and including:
- an inlet valve cam;
- an expulsor cam;
- an outlet valve cam;
- an outlet valve follower having a tube engaging portion and an inlet valve cam engaging portion, the inlet valve follower positioned between the inlet valve cam and the tube to compress the tube against the pressure plate;
- an expulsor follower having a tube engaging portion and an expulsor cam engaging portion, the expulsor valve follower positioned between the expulsor cam and the tube to compress the tube against the pressure plate;
- an outlet valve follower having a tube engaging portion and an outlet valve cam engaging portion, the outlet valve follower position between the outlet valve cam and the tube to compress the tube against the pressure plate;
- wherein the cam shaft includes means for performing one activation of the pump to pump fluid through the tube upon rotation of 180.degree..
A pump apparatus comprising:
- a pressure plate;
- a compressible tube;
- a rotatably mounted cam shaft having a rotation axis and including:
- an inlet valve cam;
- an expulsor cam;
- an outlet valve cam;
- an outlet valve follower having a tube engaging portion and an inlet valve cam engaging portion, the inlet valve follower positioned between the inlet valve cam and the tube to compress the tube against the pressure plate;
- an expulsor follower having a tube engaging portion and an expulsor cam engaging portion, the expulsor valve follower positioned between the expulsor cam and the tube to compress the tube against the pressure plate;
- an outlet valve follower having a tube engaging portion and an outlet valve cam engaging portion, the outlet valve follower positioned between the outlet valve cam and the tube to compress the tube against the pressure plate;
- wherein the inlet valve cam, the expulsor cam, and the outlet valve cam each define two lobes, wherein the cam shaft is rotatable 180.degree. to complete one activation of the pump to pump fluid through the tube.
Dependencies are inferred from the claim text.