OCCLUSION DETECTION TECHNIQUES FOR A FLUID INFUSION DEVICE HAVING A ROTARY PUMP MECHANISM AND MULTIPLE SENSOR CONTACT ELEMENTS

• US 20160367754A1
• Filed: 06/22/2015
• Published: 12/22/2016
• Est. Priority Date: 06/22/2015
• Status: Active Grant

• Current Assignee: Medtronic Minimed Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Minimed Incorporated (Medtronic Plc)
• Inventors: Alderete, Juan M. Jr., Yavorsky, Matthew William, Pananen, Jacob E.
• Granted Patent: US 9,878,095 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: A61M 2005/16868 Downstream occlusion sensors
• CPC Class Codes: A61M 2005/16872 Upstream occlusion sensors
• CPC Class Codes: A61M 5/14212 Pumping with an aspiration and an expulsion action
• 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 17/03 driven by electric motors
• CPC Class Codes: F04B 19/22 of reciprocating-piston type
• CPC Class Codes: F04B 2201/0201 Position of the piston
• CPC Class Codes: F04B 2201/02011 Angular position of a piston rotating around its own axis
• CPC Class Codes: F04B 49/065 and making use of computers
• CPC Class Codes: F04B 51/00 Testing machines, pumps, or pumping installations
• CPC Class Codes: F04B 53/10 Valves; Arrangement of valves
• CPC Class Codes: F04B 53/14 Pistons, piston-rods or piston-rod connections
• CPC Class Codes: F04B 53/16 Casings; Cylinders; Cylinder liners or heads; Fluid connections
• CPC Class Codes: F04B 53/162 Adaptations of cylinders
• 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

Abstract

A fluid infusion device includes a pump having a rotor and a stator. A rotor cam element rises from a reference surface of the rotor. The stator includes a cam element having a stator cam surface. The cam elements axially displace the rotor as the rotor revolves. Inlet and outlet valves open and close as a function of angular and axial position of the rotor. A motor actuates the rotor to pump fluid to a body, via a subcutaneous conduit. First and second contact elements are located on the rotor. A sensing element on the stator cooperates with a detection circuit to detect when the sensing element makes contact with the first sensor contact element and the second sensor contact element. The detection circuit monitors a detection signal obtained from the sensing element to determine an operating condition of the fluid pump mechanism.

Claims

1. A fluid pump mechanism comprising:

a stator comprising a stator cam element having a stator cam surface;

a rotor comprising a reference surface and a rotor cam element having a variable height rising from the reference surface, the rotor cam element cooperating with the stator cam element to axially displace the rotor, relative to the stator, as a function of angular position of the rotor;

an inlet valve that opens and closes as a function of angular and axial position of the rotor relative to the stator;

an outlet valve that opens and closes as a function of angular and axial position of the rotor relative to the stator;

a biasing element that provides a biasing force to urge the rotor toward the stator;

a first sensor contact element on the rotor and located at an angular position that follows an upper edge of the rotor cam element;

a second sensor contact element on the rotor and located at an angular position that follows the first sensor contact element; and

a sensing element on the stator, the sensing element cooperating with a detection circuit to detect when the sensing element makes contact with the first sensor contact element and the second sensor contact element;

wherein the detection circuit monitors characteristics of a detection signal obtained from the sensing element in response to angular position of the rotor to determine an operating condition of the fluid pump mechanism.

2. The fluid pump mechanism of claim 1, wherein the first and second sensor contact elements are located on the reference surface in a region that is unoccupied by the rotor cam element.

3. The fluid pump mechanism of claim 1, wherein:

the rotor comprises an endcap having a rim;

the reference surface and the rotor cam element are located inside the endcap; and

the first and second sensor contact elements are located on the rim.

4. The fluid pump mechanism of claim 1, wherein the sensing element comprises:

a first conductive spring tab electrically coupled to the detection circuit; and

a second conductive spring tab electrically coupled to the detection circuit.

5. The fluid pump mechanism of claim 1, wherein:

angular positioning of the first sensor contact element on the rotor corresponds to a first valve state that occurs after the inlet valve closes for a current pumping cycle, and before the outlet valve opens for the current pumping cycle; and

angular positioning of the second sensor contact element on the rotor corresponds to a second valve state that occurs after the outlet valve closes for the current pumping cycle, and before the inlet valve opens for a next pumping cycle.

6. The fluid pump mechanism of claim 1, wherein the detection circuit initiates an alert, alarm, or warning message in response to detecting a fault condition.

7. The fluid pump mechanism of claim 6, wherein the fault condition is a downstream occlusion or an upstream occlusion.

8. The fluid pump mechanism of claim 1, wherein, under normal operating conditions:

the sensing element makes no contact with the first sensor contact element; and

the sensing element contacts the second sensor contact element once per pumping cycle.

9. The fluid pump mechanism of claim 1, wherein, under upstream occlusion conditions:

the sensing element contacts the first sensor contact element once per pumping cycle;

the sensing element contacts the second sensor contact element once per pumping cycle; and

the detection circuit determines that an upstream occlusion has occurred based on the sensing element contacting the first and second sensor contact elements.

10. The fluid pump mechanism of claim 1, wherein, under downstream occlusion conditions:

the sensing element makes no contact with the first sensor contact element;

the sensing element makes no contact with the second sensor contact element; and

the detection circuit determines that a downstream occlusion has occurred based on the sensing element making no contact with the first and second sensor contact elements.

11. A fluid infusion device for delivering a medication fluid to a body, the fluid infusion device comprising:

a fluid pump mechanism that cooperates with a fluid cartridge module, the fluid pump mechanism comprising a rotor and a stator, the rotor comprising a reference surface and a rotor cam element having a variable height rising from the reference surface, the stator comprising a stator cam element having a stator cam surface, the rotor cam element cooperating with the stator cam element to axially displace the rotor, relative to the stator, as a function of angular position of the rotor;

an inlet valve that opens and closes as a function of angular and axial position of the rotor relative to the stator;

an outlet valve that opens and closes as a function of angular and axial position of the rotor relative to the stator;

a biasing element that provides a biasing force to urge the rotor toward the stator;

a subcutaneous conduit in fluid communication with the outlet valve;

a drive motor coupled to actuate the rotor of the fluid pump mechanism to pump medication fluid from the fluid cartridge module to the body, via the subcutaneous conduit;

a first sensor contact element on the rotor and located at an angular position that follows an upper edge of the rotor cam element;

a second sensor contact element on the rotor and located at an angular position that follows the first sensor contact element; and

a sensing element on the stator, the sensing element cooperating with a detection circuit to detect when the sensing element makes contact with the first sensor contact element and the second sensor contact element;

wherein the detection circuit monitors characteristics of a detection signal obtained from the sensing element in response to angular position of the rotor to determine an operating condition of the fluid pump mechanism.

12. The fluid infusion device of claim 11, wherein:

angular positioning of the first sensor contact element on the rotor corresponds to a first valve state that occurs after the inlet valve closes for a current pumping cycle, and before the outlet valve opens for the current pumping cycle; and

angular positioning of the second sensor contact element on the rotor corresponds to a second valve state that occurs after the outlet valve closes for the current pumping cycle, and before the inlet valve opens for a next pumping cycle.

13. The fluid infusion device of claim 12, wherein, under normal operating conditions:

the sensing element makes no contact with the first sensor contact element; and

the sensing element contacts the second sensor contact element once per pumping cycle.

14. The fluid infusion device of claim 12, wherein, under upstream occlusion conditions:

the sensing element contacts the first sensor contact element once per pumping cycle;

the sensing element contacts the second sensor contact element once per pumping cycle; and

the detection circuit determines that an upstream occlusion has occurred based on the sensing element contacting the first and second sensor contact elements.

15. The fluid infusion device of claim 12, wherein, under downstream occlusion conditions:

the sensing element makes no contact with the first sensor contact element;

the sensing element makes no contact with the second sensor contact element; and

the detection circuit determines that a downstream occlusion has occurred based on the sensing element making no contact with the first and second sensor contact elements.

16. A fluid pump mechanism comprising:

a stator comprising a stator cam element having a stator cam surface;

a rotor comprising;

an endcap having a rim;

a reference surface located inside the endcap;

a rotor cam element located inside the endcap and having a variable height rising from the reference surface, the rotor cam element cooperating with the stator cam element to axially displace the rotor, relative to the stator, as a function of angular position of the rotor;

a first sensor contact element on the rim of the endcap, and located at an angular position that follows an upper edge of the rotor cam element;

a second sensor contact element on the rim of the endcap, and located at an angular position that follows the first sensor contact element;

a biasing element that provides a biasing force to urge the rotor toward the stator;

an inlet valve that opens and closes as a function of angular and axial position of the rotor relative to the stator;

an outlet valve that opens and closes as a function of angular and axial position of the rotor relative to the stator; and

a sensing element that cooperates with a detection circuit to detect when the sensing element makes contact with the first sensor contact element and the second sensor contact element, wherein the detection circuit monitors characteristics of a detection signal obtained from the sensing element to determine an operating condition of the fluid pump mechanism.

17. The fluid pump mechanism of claim 16, wherein the sensing element comprises:

a first conductive spring tab located on the stator, and electrically coupled to the detection circuit; and

a second conductive spring tab located on the stator, and electrically coupled to the detection circuit.

18. The fluid pump mechanism of claim 16, wherein:

angular positioning of the first sensor contact element on the rotor corresponds to a first valve state that occurs after the inlet valve closes for a current pumping cycle, and before the outlet valve opens for the current pumping cycle; and

angular positioning of the second sensor contact element on the rotor corresponds to a second valve state that occurs after the outlet valve closes for the current pumping cycle, and before the inlet valve opens for a next pumping cycle.

19. The fluid pump mechanism of claim 18, wherein, under normal operating conditions:

the sensing element makes no contact with the first sensor contact element; and

the sensing element contacts the second sensor contact element once per pumping cycle.

20. The fluid pump mechanism of claim 18, wherein, under upstream occlusion conditions:

the sensing element contacts the first sensor contact element once per pumping cycle;

the sensing element contacts the second sensor contact element once per pumping cycle; and

the detection circuit determines that an upstream occlusion has occurred based on the sensing element contacting the first and second sensor contact elements.

21. The fluid pump mechanism of claim 18, wherein, under downstream occlusion conditions:

the sensing element makes no contact with the first sensor contact element;

the sensing element makes no contact with the second sensor contact element; and

the detection circuit determines that a downstream occlusion has occurred based on the sensing element making no contact with the first and second sensor contact elements.