Negative pressure wound therapy apparatus

• US 9,545,465 B2
• Filed: 05/15/2013
• Issued: 01/17/2017
• Est. Priority Date: 05/15/2012
• Status: Active Grant

• Current Assignee: Smith & Nephew PLC
• Original Assignee: Smith & Nephew PLC
• Inventors: Allen, Julie, Askem, Ben Alan, Beckett, Trevor John, Binder, Ian, Collinson, Sarah Jenny, Ferrari, Iacopo Claudio, Fryer, Christopher John, Gowans, Philip, Cowan-Hughes, John, Herd, Matthew James, Marshall, Keith, Mehta, Steven Carl, Moy, Tom, Mullen, Paul, Nicolini, Derek, Norman, Alexander David, Pryor, Neil, Riva, Christian, Stacey, Gary, Walsh, Philip
• Primary Examiner(s): Wiest, Philip R
• Assistant Examiner(s): WENG, KAI H
• Application Number:
  US14/401,356
• Publication Number:
  US 20150100045A1
• Time in Patent Office: 1,343 Days
• US Class Current: 1/1
• CPC Class Codes: A61F 13/05 specially adapted for use with sub-pressure or over-pressure therapy, wound drainage or wound irrigation, e.g. for use with negative-pressure wound therapy [NPWT]
• CPC Class Codes: A61F 2013/00174 possibility of applying pressure
• CPC Class Codes: A61M 1/732 Visual indicating means for vacuum pressure
• CPC Class Codes: A61M 1/82 Membrane pumps, e.g. bulbs
• CPC Class Codes: A61M 1/912 Connectors between dressing and drainage tube
• CPC Class Codes: A61M 1/94 with gas supply means
• CPC Class Codes: A61M 1/96 Suction control thereof
• 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
• CPC Class Codes: A61M 1/984 portable on the body
• CPC Class Codes: A61M 1/985 the dressing itself forming the collection container
• CPC Class Codes: A61M 2205/42 Reducing noise
• CPC Class Codes: A61M 2205/8206 battery-operated
• CPC Class Codes: A61M 2209/088 on the body
• CPC Class Codes: A61M 27/00 Drainage appliance for wounds or the like , i.e. wound drains, implanted drains negative pressure wound therapy devices A61M1/90; implements for holding wound open A61B17/02 ; middle ear drainage A61F11/202
• CPC Class Codes: F04B 43/0054 particularities of the flexible members
• CPC Class Codes: F04B 43/04 Pumps having electric drive
• CPC Class Codes: F04B 45/047 Pumps having electric drive
• CPC Class Codes: F04B 49/06 Control using electricity regulating by means of floats actuating electric switches F04B49/04
• CPC Class Codes: F04B 53/10 Valves; Arrangement of valves

Abstract

Some embodiments disclosed herein are directed to a pump assembly comprising a voice coil, a magnet and a diaphragm, wherein the voice coil is configured to move the diaphragm to pump a fluid through the pump assembly in response to a drive signal applied to the voice coil. Some embodiments disclosed herein are directed to an apparatus for applying negative pressure to a wound comprising a source of negative pressure configured to be coupled to a dressing, the source of negative comprising a voice coil actuator and a diaphragm, and a controller configured to produce a drive signal for the voice coil actuator.

Claims

1. An apparatus for use in negative pressure wound therapy comprising:

a pump assembly comprising;

a magnetic circuit comprising an upper pole, a lower pole spaced apart from the upper pole, and a magnet positioned between at least a portion of the upper pole and the lower pole;

an electrically conductive coil at least a portion of which is disposed between the upper and the lower pole, wherein the upper pole has a first portion and a second portion, the first pole portion extending in a generally planar direction and the second portion extending in a direction away from the first portion generally transverse to the first portion, wherein the second portion of the upper pole extends through an opening in the coil so as to shift a magnetic field of the magnet in a direction towards the lower pole;

a diaphragm; and

one or more valves configured to control a flow of fluid through the pump assembly, the one or more valves being integrated with a housing of the pump assembly,

wherein the coil is directly or indirectly coupled with the diaphragm and is configured to move at least a portion of the diaphragm to pump a fluid through the pump assembly in response to a drive signal applied to the coil.

2. The apparatus of claim 1, wherein the drive signal comprises at least one of an offset square wave drive signal and an offset sinusoidal wave drive signal.

3. The apparatus of claim 1, further comprising a wound dressing configured to sealingly surround a wound.

4. The apparatus of claim 1, wherein the pump assembly is supported on, by, partially within, or fully within a wound dressing.

5. The apparatus of claim 1, comprising a flat spring member, wherein:

a periphery of the spring member is supported within the pump assembly so as to be in a fixed position relative to the diaphragm;

a middle portion of the spring member is configured to deflect relative to the periphery of the spring member when a middle portion of the diaphragm axially deflects.

6. The apparatus of claim 5, wherein the spring member is configured to directly or indirectly exert a force on a middle portion of the diaphragm so as to displace the middle portion of the diaphragm when the apparatus is in an assembled state but before an electrical current has been applied to the coil.

7. The apparatus of claim 5, wherein the spring member is configured to alter a resonant oscillation frequency of the diaphragm member, thereby permitting the adjustment of the resonant frequency of the pump assembly to improve efficiency of the pump assembly.

8. The apparatus of claim 1, wherein the one or more valves comprise a first flap valve and a second flap valve, wherein:

the first flap valve is configured to prevent air from flowing out of a valve chamber defined by the diaphragm during an intake cycle but to permit air to flow out of the valve chamber and through an outlet port during an exhaust cycle; and

the second flap valve is configured to prevent air from flowing into the valve chamber through an inlet port during the exhaust cycle but to permit air to flow into the valve chamber during the intake cycle.

9. The apparatus of claim 8, wherein at least one of the first flap valve and the second flap valve comprises a flap portion surrounded by a frame portion, the flap portion being configured to deflect away from a relaxed position of the flap portion to block passage of air through an opening adjacent to the flap portion in response to a pressure differential between a first main surface and a second main surface of the flap portion.

10. The apparatus of claim 9, wherein the flap portion comprises a base portion and a body portion, the body portion being supported in cantilever and the flap portion being configured to deflect about the base portion, and wherein the base portion has a smaller cross-sectional area than the body portion.

11. The apparatus of claim 8, wherein at least one of the first flap valve and the second flap valve comprises a bridge valve, the bridge valve being fixed to a support member at a first end and a second opposite end of the bridge valve, and having a middle portion configured to deflect away from a relaxed position of the middle portion to block passage of air through an opening adjacent to the flap portion in response to a pressure differential between a first main surface and a second main surface of the middle portion.

12. The apparatus of claim 1, comprising a first valve support and a second valve support, wherein the one or more valves are positioned between the first and second valve supports.

13. The apparatus of claim 12, wherein the first valve support is attached to the second valve support using one or more welds such as laser welds or ultrasonic welds, clamps, screws, adhesive, or other similar methods.

14. The apparatus of claim 1, comprising a controller configured to produce a drive signal for the coil and a filter configured to filter the drive signal, wherein the drive signal comprises a first pulse-width modulation drive signal and a second pulse-width modulation drive signal, the first and second pulse-width modulation drive signals having different magnitudes.

15. The apparatus of claim 14, wherein:

the filter is further configured to filter the first pulse-width modulation drive signal to produce a first sinusoidal wave and filter the second pulse-width modulation drive signal to produce a second sinusoidal wave; and

the controller is further configured to combine the first and second sinusoidal waves to produce the sinusoidal drive signal.

16. The apparatus of claim 15, wherein the coil comprises the filter.

17. The apparatus of claim 15, wherein the first and second sinusoidal waves are phase shifted by about 180 degrees.

18. The apparatus of claim 1, wherein at least a portion of the electrically conductive voice coil is disposed radially between the upper pole and the lower pole.

19. The apparatus of claim 1, wherein the voice coil is configured to move within at least a portion of the magnetic circuit.

20. The apparatus of claim 13, wherein the second valve support is formed on an inside surface of the housing.

21. The apparatus of claim 20, wherein the inside surface of the housing comprises one or more recesses capable of supporting the one or more valves.

22. The apparatus of claim 21, wherein the one or more valves comprise a first flap valve and a second flap valve, and wherein the first and second flap valves are positioned within the one or more recesses.

23. The apparatus of claim 22, wherein the first flap valve is preloaded against a recess of the first valve support, and wherein the second flap valve is preloaded against one of the one or more recesses.

24. A wound treatment apparatus, comprising:

a pump assembly comprising;

a magnetic circuit comprising an upper pole, a lower pole spaced apart from the upper pole, and a magnet positioned between at least a portion of the upper pole and the lower pole;

an electrically conductive voice coil, at least a portion of which is disposed between the upper pole and the lower pole, the electrically conductive voice coil being configured to move within at least a portion of the magnetic circuit; and

a diaphragm,

wherein the voice coil is configured to move the diaphragm to pump a fluid through the pump assembly in response to a drive signal applied to the voice coil;

means for controlling the direction of fluid flow through the means for pumping fluid;

means for controlling the means for pumping fluid from the wound;

means for powering the means for pumping fluid from the wound;

means for packaging the means for pumping fluid in a sterile condition;

means for housing the pump assembly;

means for dressing the wound while the means for pumping pumps fluid from the wound;

means for connecting the means for dressing the wound with the means for pumping fluid from the wound; and

means for indicating to a user of the apparatus a status of the device.