Apparatus and method for reducing power consumption in a peristaltic pump mechanism

• US 6,267,559 B1
• Filed: 12/21/1999
• Issued: 07/31/2001
• Est. Priority Date: 12/21/1999
• Status: Expired due to Term

• Current Assignee: Carefusion 303 Incorporated (Becton, Dickinson & Co)
• Original Assignee: ALARIS Medical Systems, Inc. (Becton, Dickinson & Co)
• Inventors: Woolf, Darin Kent, Mossman, John Archie
• Primary Examiner(s): Walberg, Teresa
• Assistant Examiner(s): Patel, Vinod D
• Application Number:
  US09/470,318
• Time in Patent Office: 588 Days
• Field of Search: 417/44.1, 417/474, 417/471, 417/465, 417/466
• US Class Current: 417/44.1
• CPC Class Codes: A61M 5/14228 with linear peristaltic action, i.e. comprising at least three pressurising members or a helical member
• CPC Class Codes: F04B 43/082 the tubular flexible member being pressed against a wall by a number of elements, each having an alternating movement in a direction perpendicular to the axes of the tubular member and each having its own driving mechanism

Abstract

The present invention utilizes a torque compensation system and a power control feedback system to reduce power consumption in a linear peristaltic pump. The linear peristaltic infusion pump includes an electric motor, which is connected to a cam shaft with multiple cams positioned thereon. Numerous elongate fingers cooperate with the cams to partly occlude an intravenous drip tube at multiple points along the tube'"'"'s path. A torque compensation system and power feedback control system reduce the overall power consumption of the pump. A torque compensation cam positioned on the cam shaft, in combination with a torque compensation cam follower and a mechanical spring assist the motor while it is working against a rising cam follower. The power feedback control system comprises a controller which optimally adjusts the power supplied to the drive means so as to reduce overall power consumption of the pump.

Claims

1. A peristaltic pump, comprising:

a drive means;

a cam shaft driven by said drive means;

a plurality of cams positioned at spaced intervals around the circumference of said cam shaft;

a plurality of elongate fingers cooperating with said cams, said fingers capable of at least partly occluding an intravenous drip tube at multiple points along said tube'"'"'s path; and

a torque compensation system, including;

at least one torque compensation cam positioned on said cam shaft;

at least one torque compensation cam follower operatively connected to said torque compensation cam; and

an energy storage element operatively connected to said torque compensation cam follower, which forcibly engages said torque compensation cam follower against said torque compensation cam,

such that in use said torque compensation system decreases torque produced at said drive means thus reducing overall power consumption of said pump.

2. A peristaltic pump according to claim 1, wherein said drive means comprises:

a motor;

a reduction gear set connected to said motor; and

a power supply.

3. A peristaltic pump according to claim 2, wherein said motor is a direct current operated stepper motor, capable of operating at a fixed rotational rate independent of loading.

4. A peristaltic pump according to claim 3, wherein said energy storage element is a mechanical spring.

5. A peristaltic pump, comprising:

a drive means;

a cam shaft driven by said drive means;

a plurality of cams positioned at spaced intervals around the circumference of said cam shaft;

a plurality of elongate fingers cooperating with said cams, said fingers capable of at least partly occluding an intravenous drip tube at multiple points along said tube'"'"'s path; and

a power feedback control system, further comprising;

a variable output power supply, which controls power supplied to said drive means;

a transducer for measuring excess power at said drive means; and

a controller, capable of dynamically adjusting said variable output power supply by processing the measured excess power and a predetermined desired power,

such that in use said power feedback control system optimally adjusts the power supplied to said drive means so as to reduce overall power consumption of said pump.

6. A peristaltic pump according to claim 5, wherein said controller comprises:

a voltage peak detector; and

an error detector.

7. A peristaltic pump according to claim 6, wherein said error detector comprises an operational amplifier.

8. A peristaltic pump according to claim 7, wherein said predetermined desired power is set by a user of said pump, for each specific pumping rate.

9. A peristaltic pump according to claim 8, wherein said pump further comprises:

a torque compensation system comprising;

at least one torque compensation cam positioned on said cam shaft;

at least one torque compensation cam follower operatively connected to said torque compensation cam; and

an energy storage element operatively connected to said torque compensation cam follower, which forcibly engages said torque compensation cam follower against said torque compensation cam,

such that in use said torque compensation system decreases torque produced at said drive means thus reducing overall power consumption of the pump.

10. A peristaltic pump, comprising:

a stepper motor;

a cam shaft driven by said motor;

a plurality of cams positioned at spaced intervals around the circumference of said cam shaft;

a plurality of elongate fingers cooperating with said cams, said fingers capable of at least partly occluding an intravenous drip tube at multiple points along said tube'"'"'s path; and

a torque compensation system, further comprising;

at least one torque compensation cam positioned on said cam shaft;

at least one torque compensation cam follower operatively connected to said torque compensation cam; and

an energy storage element operatively connected to said torque compensation cam follower, which forcibly engages said torque compensation cam follower against said torque compensation cam; and

a power feedback control system, further comprising;

a variable output power supply, which controls power supplied to said stepper motor;

a transducer for measuring excess power at said drive means; and

a controller, capable of dynamically adjusting said variable output power supply by processing the measured excess power and a predetermined desired power,

such that in use said power feedback control system optimally adjusts the power supplied to said power source and said torque compensation system decreases torque produced at said motor, the combination of said power feedback control system and said torque compensation system, reducing overall power consumption of said pump.

11. A method of controlling the operation of a peristaltic infusion pump, in order to reduce said pump'"'"'s power consumption, comprising the steps of:

determining a desired power value;

measuring an excess power value caused by torque loading on a drive means;

processing said predetermined desired power value and said excess power value to form a new value; and

adjusting power supplied to said drive means in accordance with said new value.

12. A method according to claim 11, wherein said method further comprises the steps of:

providing at least one torque compensation cam positioned on said cam shaft;

furnishing at least one torque compensation cam follower operatively connected to said torque compensation cam; and

supplying an energy storage element operatively connected to said torque compensation cam, which forcibly engages said torque compensation cam follower against said torque compensation cam to decrease any torque produced at said drive means.