SYSTEM AND METHOD FOR MANAGING REDUCED PRESSURE DELIVERED TO A TISSUE SITE

• US 20120271256A1
• Filed: 04/19/2012
• Published: 10/25/2012
• Est. Priority Date: 04/20/2011
• Status: Active Grant

• Current Assignee: Solventum Intellectual Properties Company (Solventum Corp.)
• Original Assignee: KCI Licensing Incorporated (3M Company)
• Inventors: Locke, Christopher Brian, Blandford, David Robson, Coulthard, Richard Daniel John
• Granted Patent: US 9,474,838 B2
• Time in Patent Office: Days
• US Class Current: 604/319
• CPC Class Codes: A61M 1/742 by changing the size of a vent A61M1/7411 takes precedence
• CPC Class Codes: A61M 1/80 Suction pumps A61M1/64, A61M1/71, A61M60/00 take precedence
• CPC Class Codes: A61M 1/92 with liquid supply means
• CPC Class Codes: A61M 1/962 having pumping means on the suction site, e.g. miniature pump on dressing or dressing capable of exerting suction

Abstract

An apparatus and method for managing reduced pressure at a tissue site are disclosed. The apparatus comprises a pump for supplying reduced pressure to the tissue site, a motor coupled to the pump to propel the pump, and a drive system electrically coupled to the motor that includes a power source that provides a source of direct current power to the motor during an operational period at a substantially constant current and of sufficient magnitude to supply a targeted reduced pressure during the operational period. The drive system also includes a controller that monitors the pump'"'"'s loading on the motor by measuring the voltage across the motor to determine whether the motor voltage remains within a predetermined operational range of voltages necessary for maintaining the reduced pressure supplied by the pump proximate to the targeted reduced pressure without directly measuring the reduced pressure using a pressure sensor.

Claims

1. An apparatus for managing reduced pressure delivered to a tissue site, the apparatus comprising:

a pump adapted to provide a supply pressure for the application of reduced pressure to the tissue site;

a motor coupled to said pump to propel said pump at varying speeds in response to the pressure load of said pump on said motor; and

a drive system electrically coupled to said motor and including (a) a power source adapted to provide direct-current power to said motor at a motor current being substantially constant and of sufficient magnitude for said pump to supply a targeted pressure and at a motor voltage varying with the pressure load of said pump on said motor, and (b) a controller adapted to measure the motor voltage and determine whether the motor voltage remains within a predetermined range of voltages necessary for maintaining the supply pressure proximate the targeted pressure.

2. The apparatus of claim 1, wherein said motor is a direct-current motor.

3. The apparatus of claim 2, wherein said direct-current motor is a brushed, direct-current motor.

4. The apparatus of claim 1, wherein said pump is a diaphragm pump.

5. The apparatus of claim 1, wherein said drive system further comprises input circuitry to adjust the constant current to a value corresponding to the targeted reduced pressure.

6. The apparatus of claim 1, wherein the lower boundary of the predetermined range of voltages is a stall voltage corresponding to a stall speed of said motor that occurs when the supply pressure proximate the targeted pressure, and wherein the controller is further adapted to stop said motor for a predetermined time period when the motor voltage is less than or equal to the stall voltage.

7. The apparatus of claim 6, wherein the controller comprises a comparator to provide a stop signal when the motor voltage is less than or equal to the stall voltage, and a timer responsive to the stop signal by commencing the predetermined time period and restarting said motor after the predetermined time period.

8. The apparatus of claim 6, wherein the drive system further comprises a kick-start module responsive to the controller and adapted to periodically stop and restart said motor when the motor voltage is greater than the stall voltage.

9. The apparatus of claim 1, wherein the upper boundary of the predetermined range of voltages is a leak voltage corresponding to a leak speed of said motor that occurs when the supply pressure drops away from the targeted pressure, and wherein the controller is further adapted to apply additional power to said motor for a predetermined time period when the motor voltage is greater than or equal to the leak voltage.

10. The apparatus of claim 9, wherein the controller comprises a comparator to provide a leak signal when the motor voltage is greater than or equal to the leak voltage, and a timer responsive to the leak signal by commencing the predetermined time period and removing the additional source of power from said motor after the predetermined time period.

11. The apparatus of claim 9, wherein the drive system further comprises a kick-start module responsive to the controller and adapted to periodically stop and restart said motor when the motor voltage is less than the leak voltage.

12. The apparatus of claim 9, wherein the additional power is provided to said motor by increasing the motor current.

13. The apparatus of claim 9, wherein the additional power is provided to said motor by increasing the motor voltage.

14. The apparatus of claim 1, wherein the power source further comprises a power-on module to apply additional power to said motor for a fixed time period when the motor current is first applied to said motor at start-up, whereby said motor speeds up for the fixed time period at start-up so that the supply pressure more quickly reaches the targeted pressure.

15. The apparatus of claim 14, wherein the drive system further comprises a kick-start module responsive to the controller and adapted to periodically stop and restart said motor after the fixed time period at start-up.

16. The apparatus of claim 14, wherein the additional power is provided to said motor by increasing the motor current.

17. The apparatus of claim 14, wherein the additional power is provided to said motor by increasing the motor voltage.

18. The apparatus of claim 1, wherein the drive system further comprises a kick-start module responsive to the controller and adapted to periodically stop and restart said motor when the motor voltage is within the predetermined range of voltages.

19. The apparatus of claim 18, wherein the power source is further adapted to apply additional power to said motor for a predetermined time period to restart said motor when the motor voltage is within the predetermined range of voltages.

20. The apparatus of claim 1 further comprising:

a pressure sensor for measuring the reduced pressure applied by said pump proximate to the tissue site; and

a comparator for comparing the supply pressure to the reduced pressure proximate the tissue site.

21. An apparatus for managing reduced pressure delivered to a tissue site, the apparatus comprising:

a pump adapted to provide a supply pressure for the application of reduced pressure to the tissue site;

a direct-current motor coupled to said pump to propel said pump at varying speeds;

a power source electrically coupled to said motor to provide direct-current to said motor at a motor current being substantially constant in magnitude and of sufficient magnitude for said pump to provide the supply pressure proximate a targeted pressure whereby the motor voltage across said motor varies with the pressure load on said motor; and

a controller electrically coupled to said power source and adapted to measure the motor voltage and determine whether the motor voltage is within a predetermined range of voltages necessary for maintaining the supply pressure proximate the targeted.

22. The apparatus of claim 21, wherein the lower boundary of the predetermined range of voltages is a stall voltage corresponding to a stall speed of said motor that occurs when the supply pressure proximate the targeted pressure, and wherein the controller is further adapted to stop said motor for a predetermined time period when the motor voltage is less than or equal to the stall voltage.

23. The apparatus of claim 21, wherein the upper boundary of the predetermined range of voltages is a leak voltage corresponding to a leak speed of said motor that occurs when the supply pressure drops away from the targeted pressure, and wherein the controller is further adapted to apply additional power to said motor for a predetermined time period when the motor voltage is greater than or equal to the leak voltage.

24. The apparatus of claim 21, wherein the lower boundary of the predetermined range of voltages is a stall voltage corresponding to a stall speed of said motor that occurs when the supply pressure proximate the targeted pressure and the upper boundary of the predetermined range of voltages is a leak voltage corresponding to a leak speed of said motor that occurs when the supply pressure drops away from the targeted pressure, and wherein the controller is further adapted to stop said motor for a predetermined stop time period when the motor voltage is less than or equal to the stall voltage and apply additional power to said motor for a predetermined leak time period when the motor voltage is greater than or equal to the leak voltage.

25. The apparatus of claim 24, wherein the additional power is provided to said motor by increasing the motor current.

26. The apparatus of claim 24, wherein the additional power is provided to said motor by increasing the motor voltage.

27. The apparatus of claim 24, wherein the drive system further comprises a kick-start module responsive to the controller and adapted to periodically stop and restart said motor when the motor voltage is greater than the stall voltage and less than the leak voltage.

28. The apparatus of claim 24, wherein the power source further comprises a power-on module to apply additional power to said motor for a fixed time period when the motor current is first applied to said motor at start-up, whereby said motor speeds up for the fixed time period at start-up so that the supply pressure more quickly reaches the targeted pressure.

29. The apparatus of claim 28, wherein the drive system further comprises a kick-start module responsive to the controller and adapted to periodically stop and restart said motor after the fixed time period at start-up when the motor voltage is greater than the stall voltage and less than the leak voltage.

30. The apparatus of claim 24 further comprising:

a pressure sensor for measuring the reduced pressure applied by said pump proximate to the tissue site; and

a comparator for comparing the supply pressure to the reduced pressure proximate the tissue site.

31. A method for managing reduced pressure delivered to a tissue site, the method comprising:

providing a supply pressure from a pump for application of reduced pressure to the tissue site;

propelling the pump with a direct-current motor;

providing electrical power to the direct-current motor at a substantially constant current and of sufficient magnitude for the pump to supply a targeted pressure;

measuring the motor voltage across the direct-current motor; and

determining whether the motor voltage is within a predetermined range of voltages necessary for maintaining the supply pressure proximate the targeted pressure.