Internal cam metering pump

• US 9,416,775 B2
• Filed: 07/02/2014
• Issued: 08/16/2016
• Est. Priority Date: 07/02/2014
• Status: Active Grant

• Current Assignee: Becton, Dickinson & Co
• Original Assignee: Becton, Dickinson & Co
• Inventors: Focht, Kenneth, Gordon, Joseph, Fisk, Justin, Perry, Matthew J.
• Primary Examiner(s): Mehta, Bhisma
• Assistant Examiner(s): Ponton, James D
• Application Number:
  US14/322,432
• Publication Number:
  US 20160000999A1
• Time in Patent Office: 776 Days
• US Class Current: 1/1
• CPC Class Codes: A61M 2005/14252 with needle insertion means
• CPC Class Codes: A61M 2005/16863 Occlusion detection
• CPC Class Codes: A61M 2205/103 rotating
• CPC Class Codes: A61M 5/1413 Modular systems comprising interconnecting elements
• CPC Class Codes: A61M 5/14216 Reciprocating piston type
• CPC Class Codes: A61M 5/14244 adapted to be carried by the patient, e.g. portable on the body
• CPC Class Codes: A61M 5/16831 Monitoring, detecting, signalling or eliminating infusion flow anomalies low-level float-valves causing cut-off A61M5/40; indicating or recording presence, absence or direction of flow in general G01P13/0066
• CPC Class Codes: F04B 19/006 Micropumps F04B43/043 and F04B43/095 take precedence
• CPC Class Codes: F04B 19/025 cylinders rotating around their own axis
• CPC Class Codes: F04B 39/08 Actuation of distribution members
• CPC Class Codes: F04B 43/043 Micropumps
• CPC Class Codes: F04B 49/16 by adjusting the capacity of dead spaces of working chambers
• CPC Class Codes: F04B 7/0057 Mechanical driving means therefor, e.g. cams
• CPC Class Codes: F04B 7/0065 being mounted on the main shaft
• CPC Class Codes: F04B 7/04 in which the valving is performed by pistons and cylinders coacting to open and close intake or outlet ports
• CPC Class Codes: F04B 7/06 the pistons and cylinders being relatively reciprocated and rotated
• CPC Class Codes: F04B 9/042 the means being cams
• CPC Class Codes: F04B 9/047 the means being pin-and-slot mechanisms

Abstract

A micropump according to the invention uses an eccentric cam member rotating within a pump housing to sequentially open and close valves in the pump housing to withdraw fluid from a reservoir and provide metered amounts of the fluid to a cannula port for administration to a patient. The micropump may be used in a disposable pump for continuous infusion of medication such as insulin.

Claims

1. A micropump for delivery of medication by infusion, comprising:

a pump housing;

a piston positioned in the pump housing having a longitudinal piston axis; and

a motor adapted to rotate the piston about the piston axis;

the pump housing having an axial opening receiving the piston, a first aperture positioned radially with respect to the piston axis and communicating with a reservoir, and a second aperture radially positioned with respect to the piston axis communicating with a cannula;

the piston having an eccentric cam surface at one end thereof, said cam surface adapted to sequentially open and close the first aperture and the second aperture at respective rotational positions of the piston;

wherein

the axial position of the piston inside the pump housing determines a pump volume space;

wherein the first aperture and the second aperture each contain an O-ring seal and a spring loaded valve actuator, each valve actuator having a tip, the tips of both actuators being in clearance with the eccentric cam in a normally closed position, and a spring force on the seals being high enough to ensure that the valve actuators do not open under operating pressures of the micropump, wherein the eccentric cam sequentially biases each actuator upon rotation of the piston, releasing compression on the respective O-ring seals and permitting fluid flow through the first aperture and the second aperture, respectively.

2. The micropump according to claim 1, wherein the pump housing is stationary, and further comprising an axial position cam surface on the piston, between the motor and the eccentric cam surface, engaging a stationary member on the pump housing, and adapted to translate the piston axially within the pump housing when the piston rotates.

3. The micropump according to claim 2, wherein the stationary member on the pump housing is a cam pin received in an opening in the pump housing.

4. The micropump according to claim 1, wherein the piston is free to rotate but has a fixed axial position and wherein the pump housing is free to translate axially but has a fixed rotational position.

5. The micropump according to claim 1, further comprising a connecter between the motor and the piston, the connector transmitting torque between the motor and the piston, and engaging the piston to permit axial movement of the piston with respect to the connector and prohibit rotational movement of the piston with respect to the connector.

6. The micropump according to claim 5, wherein an axially elongated slot on the pump piston engages a tab on the connector to permit axial movement of the piston with respect to the connector and prohibit rotational movement of the piston with respect to the connector.

7. The micropump according to claim 1, further comprising a microprocessor, and a travel sensor having a contact switch communicating with the microprocessor triggered by rotation of the piston through a complete cycle.

8. The micropump according to claim 1, wherein the reservoir has at least one flexible wall.

9. The micropump according to claim 1, further comprising a microprocessor, a cannula deployment mechanism, a volume sensor in operative communication with the reservoir, a travel sensor in operative communication with the pump piston, and an error condition sensor in operative communication with a fluid line between the second aperture in the pump housing and the cannula, and wherein the motor, the cannula deployment mechanism, the volume sensor, the travel sensor and the error condition sensor are all in operative communication with the microprocessor.

10. A method for delivering medication to a patient by infusion with the pump according to claim 9, comprising the steps of providing instructions to the microprocessor to deploy the cannula, causing the piston to rotate, withdrawing a volume of medication into the pump volume space from the reservoir and expelling the volume of medication through the cannula for infusion of an infusion dosage to a patient.

11. The method according to claim 10, wherein the medication is insulin and the infusion dosage comprises an infusion over one to five days.

12. The method according to claim 11, further comprising the step of disposing of the pump after delivery of the infusion dosage.

13. The method according to claim 10, wherein the infusion dosage comprises a basal segment and at least one bolus segment.

14. The method according to claim 10, wherein the pump volume space is in a range of 1 μ

l to 10 μ

l and an infusion dosage is delivered by an integer number of rotations of the piston through 360 degrees.

15. The method according to claim 10, wherein the instructions provided to the microprocessor are programmed with user operable controls located on a wearable pump housing.