WO2021059192A1

WO2021059192A1 - Medical fluid pump with audible alarms

Info

Publication number: WO2021059192A1
Application number: PCT/IB2020/058947
Authority: WO
Inventors: Prathamesh Madhav KHARKAR; Mauro ALANIS; Fernando D. CHEN
Original assignee: Kci Licensing, Inc.
Priority date: 2019-09-25
Filing date: 2020-09-24
Publication date: 2021-04-01

Abstract

A medical therapy device configured to pump fluids. The medical therapy device includes: i) a housing; ii) a DC pump disposed within the housing and configured to pump a fluid into and out of an internal chamber; and iii) a motor control unit disposed within the housing and configured to control the operation of the DC pump. In a normal operating mode, the motor control unit causes the DC pump to rotate and to pump the fluid into and out of the internal chamber. In an alarm mode, the motor control unit causes the DC pump to vibrate without rotating, the vibration of the DC pump generating an alarm signal that may be sensed outside of the housing by an operator.

Description

MEDICAU FUUID PUMP WITH AUDIBUE AUARMS

CROSS-REFERENCE TO REUATED APPUICATIONS [0001] This application claims the benefit of priority to U.S. Provisional Application No. 62/905,838, filed on September 25, 2019, which is incorporated herein by reference in its entirety.

TECHNICAU FIEUD

[0002] The invention set forth in the appended claims relates generally to tissue treatment systems that may be suitable for treating a tissue site with reduced pressure, and more particularly, but without limitation, to systems and apparatuses for pumping fluids that provide an audible alarm without the use of an audio speaker.

BACKGROUND

[0003] Clinical studies and practice have shown that reducing pressure in proximity to a tissue site can augment and accelerate growth of new tissue at the tissue site. The applications of this phenomenon are numerous, but it has proven particularly advantageous for treating wounds. Regardless of the etiology of a wound, whether trauma, surgery, or another cause, proper care of a wound is important to the outcome. Treatment of wounds or other tissue with reduced pressure may be commonly referred to as “negative-pressure therapy,” but is also known by other names, including “negative- pressure wound therapy,” “reduced-pressure therapy,” “vacuum therapy,” and “vacuum-assisted closure,” for example . Negative-pressure therapy may provide a number of benefits, including migration of epithelial and subcutaneous tissues, improved blood flow, and micro-deformation of tissue at a wound site. Together, these benefits can increase development of granulation tissue and reduce healing times.

[0004] While the clinical benefits of negative-pressure therapy are widely known, the cost and complexity of negative-pressure therapy can be a limiting factor in its application, and the development and operation of negative-pressure systems, components, and processes continues to present significant challenges to manufacturers, healthcare providers, and patients.

SUMMARY

[0005] New and useful systems and apparatuses related to tissue treatment are set forth in the appended claims. Illustrative embodiments are also provided to enable a person skilled in the art to make and use the claimed subject matter.

[0006] In some example embodiments, a medical therapy device may include: i) a housing; ii) a DC pump disposed within the housing and configured to pump a fluid into and out of an internal chamber; and iii) a motor control unit disposed within the housing and configured to control the operation of the DC pump. In a normal operating mode, the motor control unit causes the DC pump to rotate and to pump the fluid into and out of the internal chamber. In an alarm mode, the motor control unit causes the DC pump to vibrate without rotating, the vibration of the DC pump generating an alarm signal that may be sensed outside of the housing by an operator.

[0007] In one embodiment, the motor control unit generates a pulse-width modulated (PWM) signal that drives the DC pump.

[0008] In another embodiment, in the normal operating mode, a duty cycle of the PWM signal generates a first effective DC voltage that exceeds a minimum threshold level sufficient to cause the DC pump to rotate.

[0009] In still another embodiment, in the alarm mode, the duty cycle of the PWM signal generates a second effective DC voltage that does not exceed the minimum threshold level sufficient to cause the DC pump to rotate.

[0010] In yet another embodiment, in the alarm mode, the second effective DC voltage is sufficient to cause the DC pump to vibrate.

[0011] In a further embodiment, in the alarm mode, the second effective DC voltage causes the DC pump to vibrate at an audible frequency that may be heard by the operator.

[0012] In a still further embodiment, in the alarm mode, the second effective DC voltage causes the DC pump to vibrate such that a haptic alarm is generated that may be felt by the operator.

[0013] In a yet further embodiment, the motor control unit is configured to receive a first control signal, wherein, in response to the first control signal, the motor control unit enters the normal operating mode.

[0014] In one embodiment, the motor control unit is further configured to receive a second control signal, wherein, in response to the second control signal, the motor control unit enters the alarm mode.

[0015] In another embodiment, the first and second control signals are received from an external source associated with the medical therapy device.

[0016] In still another embodiment, the motor control unit is configured to receive at least one alarm signal during the alarm mode and, in response to the at least one alarm signal, the motor control unit causes the DC pump to vibrate without rotating.

[0017] In yet another embodiment, the at least one alarm signal is received from at least one sensor associated with the medical therapy device.

[0018] In a further embodiment, the at least one alarm signal indicates that the at least one sensor has detected one of: i) a seal leak; ii) a low battery level; or iii) an overpressure condition.

[0019] In some example embodiments, a medical therapy device may include: i) a pump configured to pump fluid; and ii) a motor control unit configured to control the operation of the pump, wherein the motor control unit causes the pump to vibrate without pumping fluid, the vibration of the pump generating an alarm signal that may be sensed by an operator. [0020] In one embodiment, the motor control unit causes the pump to vibrate without pumping fluid in an alarm mode.

[0021] In another embodiment, the motor control unit causes the pump to pump fluid in a normal operating mode.

[0022] In still another embodiment, the pump is a brushless direct current (DC) pump.

[0023] In yet another embodiment, the motor control unit generates a pulse-width modulated (PWM) signal that drives the DC pump, wherein a duty cycle of the PWM signal causes the DC pump to pump fluid in the normal operating mode and causes the DC pump to vibrate without pumping fluid in the alarm mode.

[0024] Objectives, advantages, and a preferred mode of making and using the claimed subject matter may be understood best by reference to the accompanying drawings in conjunction with the following detailed description of illustrative example embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 is a block diagram of an example embodiment of a therapy system that can provide negative-pressure therapy in accordance with this specification;

[0026] Figure 2 is a perspective view of an example embodiment of a therapy unit that may be associated with some example embodiments the therapy system of Figure 1 ;

[0027] Figure 3 is an exploded, perspective view of the example therapy unit of Figure 2;

[0028] Figure 4 is a perspective view of an internal portion of the example therapy unit of Figure 2, illustrating example embodiments of a multi-function mount and a pneumatic coupler in a partially assembled configuration within the therapy unit;

[0029] Figure 5 is a perspective view of an internal portion of the example therapy unit of Figure 2, shown in a fully assembled configuration;

[0030] Figure 6 is a detail view of an example embodiment of pneumatic coupler that may be associated with some example embodiments of the therapy unit of Figure 2;

[0031] Figure 7 is a side view of the multi -function mount and the pneumatic coupler of Figure 4, illustrating additional features that may be associated with some example embodiments.

[0032] Figure 8 is a simplified functional block diagram of an exemplary embodiment of a brushless DC pump system configured to generate an acoustic alarm and/or a haptic alarm according to the principles of this disclosure;

[0033] Figure 9A and 9B illustrate exemplary PWM signals having selected duty cycles;

[0034] Figure 10 is a flow diagram illustrating the operation of the brushless DC pump system according to the principles of this disclosure. DESCRIPTION OF EXAMPLE EMBODIMENTS

[0035] The following description of example embodiments enables a person skilled in the art to make and use the subject matter set forth in the appended claims. Certain details already known in the art may be omitted. Therefore, the following detailed description is illustrative and non-limiting.

[0036] The example embodiments may also be described herein with reference to spatial relationships between various elements or to the spatial orientation of various elements depicted in the attached drawings. In general, such relationships or orientation assume a frame of reference consistent with or relative to a patient in a position to receive treatment. However, as recognized by those skilled in the art, this frame of reference is merely a descriptive expedient rather than a strict prescription.

[0037] An exemplary negative-pressure therapy device may alert an operator (i.e., a clinician) about an undesirable event (e.g., a seal leak, a low battery, overpressure, etc.) by means of an audible alarm. To avoid using a built-in speaker or an attached speaker that may generate potentially harmful electromagnetic interference signals, the present disclosure describes an improved negative-pressure therapy device that includes a novel alarm system that uses the existing diaphragm pump of the negative- pressure therapy device to generate an audible alarm and/or haptic alarm, without incorporating an audio speaker. The negative-pressure therapy device described herein is by way of example only and should not be construed to limit the scope of the present disclosure. The novel alarm apparatus and method may be incorporated into any type of medical device that is configured to generate an audible alarm.

[0038] Figure 1 illustrates an example embodiment of a therapy system 100 in accordance with this specification. The therapy system 100 may include a dressing and pressure source, such as a negative-pressure source. For example, a dressing 102 may be fluidly coupled to a pressure source 104, which may be a negative-pressure source 104. A controller 106 may also be fluidly and/or electronically coupled to the dressing 102 and the negative-pressure source 104. A dressing generally includes a cover and a tissue interface. The dressing 102, for example, may include a cover 108 and a tissue interface 110. The therapy system 100 may also include a fluid container, such as a container 112, coupled to the dressing 102 and to the negative-pressure source 104.

[0039] Components of the therapy system 100 may be coupled directly or indirectly. For example, the negative-pressure source 104 may be directly coupled to the controller 106 and indirectly coupled to the dressing 102 through the controller 106. In some embodiments, components may be coupled by virtue of physical proximity, being integral to a single structure, or being formed from the same piece of material. Coupling may also include mechanical, thermal, electrical, or chemical coupling or bonding in some contexts.

[0040] Components may also be fluidly coupled to each other to provide a path for transferring fluids, such as liquid and/or gas, between the components. In some embodiments, for example, components may be fluidly coupled through a fluid conductor. A “fluid conductor,” as used herein, broadly refers to a tube, pipe, hose, conduit, or other structure with one or more lumina adapted to convey a fluid between two ends. A tube, for example, is typically an elongated, cylindrical structure with some flexibility, but the geometry and rigidity may vary.

[0041] In operation, the tissue interface 110 may be placed within, over, on, or otherwise proximate to a tissue site. The cover 108 may be placed over the tissue interface 110 and sealed to tissue near the tissue site. For example, the cover 108 may be sealed to undamaged epidermis peripheral to a tissue site. Thus, the dressing 102 can provide a sealed therapeutic environment proximate to a tissue site, substantially isolated from the external environment, and the negative-pressure source 104 can reduce the pressure in the sealed therapeutic environment. Negative pressure applied across the tissue site through the tissue interface 110 in the sealed therapeutic environment can induce macrostrain and microstrain in the tissue site, as well as remove exudates and other fluids from the tissue site, which can be collected in container 112 and disposed of properly.

[0042] The process of reducing pressure may be described illustratively herein as “delivering,” “distributing,” or “generating” negative pressure, for example. In general, exudates and other fluids flow toward lower pressure along a fluid path. Thus, in the context of a system for negative-pressure therapy, the term “downstream” may refer to a location in a fluid path relatively closer to a negative-pressure source, and conversely, the term “upstream” may refer to a location in a fluid path relatively further away from a negative-pressure source. Similarly, features may be described in terms of a fluid “inlet” or “outlet” in such a frame of reference. This orientation is generally presumed for purposes of describing various features and components of negative-pressure therapy systems herein. However, the fluid path may also be reversed in some applications (such as by substituting a positive-pressure source for a negative-pressure source), and thus, this descriptive convention should not be construed as limiting.

[0043] The term “tissue site” in this context broadly refers to a wound or defect located on or within tissue, including but not limited to, bone tissue, adipose tissue, muscle tissue, neural tissue, dermal tissue, vascular tissue, connective tissue, cartilage, tendons, or ligaments. A wound may include chronic, acute, traumatic, subacute, and dehisced wounds, partial-thickness bums, ulcers (such as diabetic, pressure, or venous insufficiency ulcers), flaps, and grafts, for example. The term “tissue site” may also refer to areas of any tissue that are not necessarily wounded or defective, but are instead areas in which it may be desirable to add or promote the growth of additional tissue. For example, negative pressure may be used in certain tissue areas to grow additional tissue that may be harvested and transplanted to another tissue location.

[0044] “Negative pressure” generally refers to a pressure less than a local ambient pressure, such as the ambient pressure in a local environment external to a sealed therapeutic environment provided by the dressing 102. In many cases, the local ambient pressure may also be the atmospheric pressure at which a tissue site is located. In some examples, the pressure may be less than a hydrostatic pressure associated with tissue at the tissue site. Unless otherwise indicated, values of pressure stated herein are gauge pressures. Similarly, references to increases in negative pressure typically refer to a decrease in absolute pressure, while decreases in negative pressure typically refer to an increase in absolute pressure.

[0045] The negative-pressure source 104 may be, for example, a reservoir of air at a negative pressure, or may be a manual or electrically-powered device that can reduce the pressure in a sealed volume, such as a vacuum pump, a suction pump, a wall suction port available at many healthcare facilities, or a micro-pump. A negative-pressure source may be housed within or used in conjunction with other components, such as sensors, processing units, alarm indicators, memory, databases, software, display devices, or user interfaces that further facilitate negative-pressure therapy. While the amount and nature of negative pressure applied to a tissue site may vary according to therapeutic requirements, the pressure is generally a low vacuum, also commonly referred to as a rough vacuum, between -5 mm Hg (-667 Pa) and -500 mm Hg (-66.7 kPa). Common therapeutic ranges are between -75 mm Hg (-9.9 kPa) and -300 mm Hg (-39.9 kPa).

[0046] The tissue interface 110 can be adapted to contact a tissue site. The tissue interface 110 may be partially or fully in contact with the tissue site. If the tissue site is a wound, for example, the tissue interface 110 may partially or completely fill the wound, or may be placed over the wound. The tissue interface 110 may take many forms, and may have many sizes, shapes, or thicknesses depending on a variety of factors, such as the type of treatment being implemented or the nature and size of a tissue site. For example, the size and shape of the tissue interface 110 may be adapted to the contours of deep and irregular shaped tissue sites.

[0047] In some embodiments, the tissue interface 110 may be a manifold. A "manifold" in this context generally includes any substance or structure providing a plurality of pathways adapted to collect or distribute fluid across a tissue site under negative pressure. For example, a manifold may be adapted to receive negative pressure from a source and distribute the negative pressure through multiple apertures across a tissue site, which may have the effect of collecting fluid from across a tissue site and drawing the fluid toward the source. In some embodiments, the fluid path may be reversed or a secondary fluid path may be provided to facilitate delivering fluid across a tissue site.

[0048] In some illustrative embodiments, the pathways of a manifold may be channels interconnected to improve distribution or collection of fluids across a tissue site. For example, cellular foam, open-cell foam, reticulated foam, porous tissue collections, and other porous material such as gauze or felted mat generally include pores, edges, and/or walls adapted to form interconnected fluid pathways. Liquids, gels, and other foams may also include or be cured to include apertures and flow channels. In some illustrative embodiments, a manifold may be a porous foam material having interconnected cells or pores adapted to uniformly or quasi-uniformly distribute negative pressure to a tissue site. The foam material may be either hydrophobic or hydrophilic. In one non-limiting example, a manifold may be an open-cell, reticulated polyurethane foam such as GRANUFOAM^® dressing available from Kinetic Concepts, Inc. of San Antonio, Texas. [0049] In an example in which the tissue interface 110 may be made from a hydrophilic material, the tissue interface 110 may also wick fluid away from a tissue site, while continuing to distribute negative pressure to the tissue site. The wicking properties of the tissue interface 110 may draw fluid away from a tissue site by capillary flow or other wicking mechanisms. An example of a hydrophilic foam is a polyvinyl alcohol, open-cell foam such as V.A.C. WHITEFOAM^® dressing available from Kinetic Concepts, Inc. of San Antonio, Texas. Other hydrophilic foams may include those made from polyether. Other foams that may exhibit hydrophilic characteristics include hydrophobic foams that have been treated or coated to provide hydrophilicity.

[0050] The tissue interface 110 may further promote granulation at a tissue site when pressure within the sealed therapeutic environment is reduced. For example, any or all of the surfaces of the tissue interface 110 may have an uneven, coarse, or jagged profile that can induce microstrains and stresses at a tissue site if negative pressure is applied through the tissue interface 110.

[0051] In some embodiments, the tissue interface 110 may be constructed from bioresorbable materials. Suitable bioresorbable materials may include, without limitation, a polymeric blend of polylactic acid (PFA) and polygly colic acid (PGA). The polymeric blend may also include without limitation polycarbonates, polyfumarates, and capralactones. The tissue interface 110 may further serve as a scaffold for new cell-growth, or a scaffold material may be used in conjunction with the tissue interface 110 to promote cell-growth. A scaffold is generally a substance or structure used to enhance or promote the growth of cells or formation of tissue, such as a three-dimensional porous structure that provides a template for cell growth. Illustrative examples of scaffold materials include calcium phosphate, collagen, PFA/PGA, coral hydroxy apatites, carbonates, or processed allograft materials.

[0052] In some embodiments, the cover 108 may provide a bacterial barrier and protection from physical trauma. The cover 108 may also be constructed from a material that can reduce evaporative losses and provide a fluid barrier between two components or two environments, such as between a therapeutic environment and a local external environment. The cover 108 may be, for example, an elastomeric fdm or membrane that can be sealed around a tissue site to maintain a negative pressure at the tissue site for a given negative-pressure source. In some example embodiments, the cover 108 may be a polymer drape, such as a polyurethane fdm, that is permeable to water vapor but impermeable to liquid. Such drapes typically have a thickness in the range of 25-50 microns. For permeable materials, the permeability generally should be low enough that a desired negative pressure may be maintained.

[0053] An attachment device may be used to attach the cover 108 to an attachment surface, such as undamaged epidermis, a gasket, or another cover. The attachment device may take many forms. For example, an attachment device may be a medically-acceptable, pressure -sensitive adhesive that extends about a periphery, a portion, or an entire sealing member. In some embodiments, for example, some or all of the cover 108 may be coated with an acrylic adhesive having a coating weight between 25-65 grams per square meter (g.s.m.). Thicker adhesives, or combinations of adhesives, may be applied in some embodiments to improve the seal and reduce leaks. Other example embodiments of an attachment device may include a double-sided tape, paste, hydrocolloid, hydrogel, silicone gel, or organogel.

[0054] The container 112 is representative of a container, canister, pouch, or other storage component, which can be used to manage exudates and other fluids withdrawn from a tissue site. In many environments, a rigid container may be preferred or required for collecting, storing, and disposing of fluids. In other environments, fluids may be properly disposed of without rigid container storage, and a re-usable container could reduce waste and costs associated with negative-pressure therapy.

[0055] Figure 2 is a perspective view of a therapy unit 200, illustrating additional details that may be associated with some example embodiments of the therapy system 100. The therapy unit 200 may include an enclosure 202 for the pressure source 104 or negative pressure source, and may also include a user interface 204. In some embodiments, the therapy unit 200 may also integrate other components, such as the controller 106 or the container 112, for example.

[0056] Figure 3 is an exploded view of the therapy unit 200, illustrating additional details that may be associated with some embodiments. As illustrated in the example embodiment of Figure 3, the therapy unit 200 may include the enclosure 202, a pressure source 302, a control board 304, a pneumatic coupler 306, a power source 308, and a multi-function mount 310. The pressure source 302 is an example embodiment of the negative-pressure source 104 in Figure 1. In some example embodiments, the power source 308 may be, without limitation, a battery, capacitor, transformer, regulator, or electrical adapter configured to receive and to convert power from an outside source, such as a wall outlet, for use with the therapy unit 200.

[0057] The control board 304 is an example embodiment of the controller 106 in Figure 1. The control board 304 may be configured to control the pressure source 302 and may be positioned in the enclosure 202 in communication with the power source 308 and the pressure source 302. The control board 304 may control the pressure source 302, for example, according to a logic control algorithm stored on or associated with the control board 304, a user input from the user interface 204, or a signal from a sensor. The control board 304 may include or communicate with various sensors, such as a pressure transducer, and one or more valves, such as a solenoid valve, to suit a particular application.

[0058] Components of the therapy system 100 and the therapy unit 200 may be omitted or additional components may be added in various embodiments to suit a particular application. Accordingly, components or features described in the example embodiments herein may not be deemed essential or required to practice the invention as defined by the appended claims.

[0059] As illustrated in Figure 3, some embodiments of the enclosure 202 may include a first housing 312 and a second housing 314, which may be coupled to form the enclosure 202 and to enclose components of the therapy unit 200. The first housing 312 may include the interface 204 in some embodiments. Further, the first housing 312 may include a plurality of first mating stand-offs 316 and the second housing 314 may include a plurality of second mating stand-offs 318. The first mating stand offs 316 may be configured to mate with the second mating stand-offs 318 for coupling the first housing 312 to the second housing 314. A gasket (not shown) or an elastomeric interface button may be located, for example, between the first housing 312 and the second housing 314 to provide additional sealing or further functionality.

[0060] In some embodiments, the multi -function mount 310 may be coupled to the enclosure 202 by a snap-fit assembly 320, such as, for example, a protrusion 320a and a catch 320b configured to mate with one another. The protrusion 320a or the catch 320b may be configured to yield or deflect when inserted into or brought into contact with one another such that mating surfaces of the protrusion 320a and the catch 320b become coupled. Further, in some embodiments, the multi-function mount 310 may be supported within the enclosure 202 by a plurality of support tabs 322. The support tabs 322 may be configured to contact the multi -function mount 310 within the enclosure 202.

[0061] In some embodiments, the second housing 314 may be coupled to the multi-function mount 310, and the first housing 312 may include the plurality of support tabs 322. The support tabs 322 may extend outward from the first housing 312 and may be configured contact and to support the multi -function mount 310 when the first housing 312 is coupled to the second housing 314. In some embodiments, the support tabs 322 may exert a compressive force on the multi -function mount 310 when the first housing 312 is coupled to the second housing 314. Further, in some embodiments, the support tabs 322 may be received within or aligned relative to a pocket 324 or surface feature of the multi function mount 310 to provide support or to prevent lateral movement of the multi-function mount 310 within the enclosure 202.

[0062] Referring to Figures 3-5, in some embodiments, the enclosure 202 may include at least one pneumatic conduit 326. The pneumatic conduit 326 may be, for example, a fluid conductor, a fluid pathway, or a conduit integrally formed as part of the enclosure 202, molded within a substrate material of the enclosure 202, or coupled to a surface of the enclosure 202. In embodiments in which the pneumatic conduit 326 is formed from or as part of the substrate material of the enclosure 202, the pneumatic conduit 326 may be referred to as an integrated pneumatic conduit. As a further example, the pneumatic conduit 326 may be formed as a channel, groove, furrow, cut, depression, or gutter in or within a surface of the enclosure 202. In some embodiments, the enclosure 202 may be manufactured, in whole or in part, with a molding process, such as injection molding.

[0063] Many negative -pressure therapy systems may use a reciprocating diaphragm or piston pump to generate negative pressure for therapy. For example, the pressure source 302 may be a reciprocating pump comprising a motor and a pump assembly including a variable volume cavity closed by a diaphragm mechanically coupled to the motor. In some embodiments, the motor may be a brushless DC motor that drives a cam that engages the diaphragm. In operation, this type of pump typically emits pulses or pressure waves during operational modes when the motor engages the diaphragm, which can create noise and vibration generated by the operation of the motor and the pump assembly, i.e., operational vibration. Noise can be particularly problematic in smaller pumps that produce relatively high airflow rates, since smaller pumps generally rotate at a higher speed to produce higher flow rates. Excessive noise can interfere with patient compliance, particularly in public places or at night. Operational vibrations that may be communicated to other components of the enclosure 202 degrading operation of those components.

[0064] Referring to Figures 4-5, the multi -function mount 310 may be coupled within the enclosure 202. In some embodiments, the pressure source 302 and the power source 308 may be carried by the multi-function mount 310. In some embodiments, the multi -function mount 310 may include or be formed of a resilient material configured to dampen the operational vibration of the pressure source 302 as described above. For example, the multi-function mount 310 may include a semi-rigid material having a hardness between 20 Shore A to 75 Shore A. In some embodiments and without limitation, the multi -function mount 310 may be manufactured from a thermoplastic elastomer material, such as, for example, KRAIBURG THERMOFAST K TF5 STE.

[0065] In some embodiments, the multi -function mount 310 may include one or more pneumatic seals 328, which may be integrally formed as part of the multi -function mount 310 and configured to provide a pneumatic seal relative to the at least one pneumatic conduit 326 within the enclosure 202. The control board 304 and other components of the therapy unit 200 may include one or more suitable pneumatic connections configured to be coupled to or sealingly engaged with the pneumatic seal 328 carried by the multi-function mount 310. As shown in the example of Figure 4, the pneumatic seals 328 may have a circular or annular shape configured to seal around a port, aperture, or opening in fluid communication with one or more of the pneumatic conduits 326. The pneumatic seals 328 may have other shapes or configurations in other embodiments. Further, the positioning or integration of the pneumatic seals 328 as a component of the multi -function mount 310 may enhance assembly by automatically locating and positioning the pneumatic seals 328 relative to the pneumatic conduits 326 when the multi-function mount 310 is coupled to the enclosure 202.

[0066] In some embodiments, the multi -function mount 310 may include a mount base 330 and one or more capturing members 332 configured to extend outward from the mount base 330. At least one of the capturing members 332 may be configured to contact the power source 308 or the pressure source 302 on at least two contact surfaces 334, which may be non-coplanar contact surfaces. For example, at least one of the capturing members 332 may be configured to contact the power source 308 or the pressure source 302 at a first contact surface 334a and a second contact surface 334b positioned non-coplanar to the first contact surface 334a. The capturing members 332 may be configured to provide an interference fit with the power source 302 or the pressure source 308.

[0067] In some embodiments, the multi-function mount 310 may include one or more isolation bosses 336. The one or more isolation bosses 336 may be configured to contact the power source 308 or the pressure source 302 to prevent translational or other movement of the pressure source 302 or the power source 308. The one or more isolation bosses 336 may be configured to contact the power source 308 or the pressure source 302 at a third contact surface 334c positioned non-coplanar to the first contact surface 334a and the second contact surface 334b. In some embodiments, the mount base 330 may be configured to contact the power source 302 or the pressure source 308 at a fourth contact surface 334d positioned non-coplanar to the first contact surface 334a, the second contact surface 334b, and the third contact surface 334c. The first contact surface 334a, the second contact surface 334b, the third contact surface 334c, and the fourth contact surface 334d may each he in a separate plane positioned normal to or facing one another.

[0068] As used in this disclosure, the term non-coplanar may refer to a point or surface that does not lie in the same geometric plane as another point or surface. In some embodiments, the first contact surface 334a of one or more of the capturing members 332 may lie in a separate plane opposite from and facing the first contact surface 334a of another of the capturing members 332. In this configuration, the first contact surface 334a of one of the capturing members 332 may face the first contact surface 334a of another of the capturing members 332 such that the pressure source 302 or the power source 308 may be captured between the opposing first contact surfaces 334a, and prevented from translational or other undesired movement along an x-axis.

[0069] Further, in some embodiments, the third contact surface 334c of one or more of the isolation bosses 336 may lie in a separate plane opposite from and facing the third contact surface 334c of another of the isolation bosses 336. In this configuration, the third contact surface 334c of one of the isolation bosses 336 may face the third contact surface 334c of another of the isolation bosses 336 such that the pressure source 302 or the power source 308 may be captured between the opposing third contact surfaces 334c, and prevented from translational or other undesired movement along a y-axis.

[0070] Further, in some embodiments, the second contact surface 334b of one or more of the capturing members 332 may lie in a separate plane and opposite from and facing the fourth contact surface 334d of the mount base 330. In this configuration, the second contact surface 334b may face the fourth contact surface 334d such that the pressure source 302 or the power source 308 is captured between the opposing second contact surface 334b and the fourth contact surface 334d, and prevented from translational or other undesired movement along a z-axis.

[0071] The x-axis, y-axis, and z-axis described in the above embodiments may be positioned normal or perpendicular relative to one another as shown in Figure 4. Preventing translational or other undesired movement of the pressure source 302 or the power source 308 along one or more of the axes as described in these example embodiments may provide support and additionally prevent operational vibration from the pressure source 302 or the power source 308 from being communicated to other parts of the enclosure 202.

[0072] Referring to Figures 3-6, the pneumatic coupler 306 may be configured to fluidly couple the pressure source 302 within the enclosure 202 to the therapy unit 200 and other components of the therapy system 100. The pneumatic coupler 306 may be a separate component coupled to the therapy unit 200 or the multi-function mount 310, for example. In other example embodiments, the pneumatic coupler 306 may be formed integrally with the therapy unit 200 or the multi -function mount 310. Further, in some embodiments, the pneumatic coupler 306 may be configured to support the pressure source 302 within the enclosure 202 and to prevent operational vibrations from being transmitted to the enclosure 202. For example, at least by virtue of being a single integrated and separable component having separate connectivity within the enclosure 202, in some embodiments, the pneumatic coupler 306 may provide improved reduction in both pneumatic noise and mechanical noise, which may be associated with or created by the operation of the pressure source 302. Further, the pneumatic coupler 306 may provide an additional mounting point or connection point between the pressure source 302 and the enclosure 202, which may provide additional support and stability to the pressure source 302 within the enclosure 202.

[0073] Referring to Figures 4-7, the pneumatic coupler 306 may include a source inlet port 340 in fluid communication with a mount inlet port 342 through the pneumatic coupler 306 and a source outlet port 344 in fluid communication with a mount outlet port 346 through the pneumatic coupler 306. Referring more specifically to Figure 7, the source inlet port 340 is in fluid communication with the mount inlet port 342 through an inlet pathway 348 disposed within the pneumatic coupler 306. The source outlet port 344 is in fluid communication with the mount outlet port 346 through an outlet pathway 350 disposed within the pneumatic coupler 306. The inlet pathway 348 and the outlet pathway 350 are separate from one another. In some embodiments, the pneumatic coupler 306 may include an inlet expansion chamber 352 within the inlet pathway 348 and an outlet expansion chamber 354 within the outlet pathway 350 disposed through the pneumatic coupler 306. The inlet expansion chamber 352 may increase a volume of a portion of the inlet pathway 348, and the outlet expansion chamber 354 may increase a volume of a portion of the outlet pathway 350. The volume, diameter, or size of the inlet expansion chamber 352 or the outlet expansion chamber 354 may be adjusted in some embodiments to reduce noise levels resulting from the operation of the pressure source 302. The volume of the inlet expansion chamber 352 and the outlet expansion chamber 354 may be sized sufficiently to dissipate fluid flow acoustics or pressure spikes that may be created by the pressure source 302. In some embodiments, the inlet expansion chamber 352 or the outlet expansion chamber 354 may also include baffles or sound absorbing foam to further reduce sound associated with fluid flow from the pressure source 302.

[0074] Referring to Figure 6, in some embodiments, the pneumatic coupler 306 may include a cable guide 360. In some embodiments, the cable guide 360 may extend outward from and over-lapping an exterior surface 362 of the pneumatic coupler 306 to define a three-sided surrounding relative to the exterior surface 362 of the pneumatic coupler 306 that is configured to support a cable or wire therein. In other embodiments, the cable guide 360 may be configured as a tab including a hole or aperture sized to receive a cable or wire and associated connectors. The cable guide 362 may simplify assembly and reduce stress on components of the therapy unit 200, which may be caused by routing cables or wires to the components.

[0075] Further, in some embodiments, the pneumatic coupler 306 may include at least one reinforcement rib 364 extending outward from and surrounding a perimeter 366 of the source inlet port 340 and the source outlet port 344. In some embodiments, the at least one reinforcement rib 364 may additionally or alternatively be configured or positioned to extend outward from and surrounding a perimeter 368 of the mount inlet port 342 and the mount outlet port 346. The reinforcement rib 364 may add stiffness and rigidity to help reduce or eliminate material creep or movement in the pneumatic coupler 306, which may improve the sealing ability and reliability of the pneumatic coupler 306, particularly after extended periods of storage or use.

[0076] In operation, the therapy unit 200 may be coupled to a canister, such as the container 112 of Figure 1, which can be fluidly coupled to a dressing, such as the dressing 102 of Figure 1. The pressure source 302 can produce a prescribed negative pressure, which can be distributed to the container 112 through a fluidic connection. The negative pressure can then be distributed through the container 112 to the dressing 102. In some embodiments, the container 112 may be omitted or positioned within the enclosure 202 of the therapy unit 200 in which a direct fluidic connection may be made between the therapy unit 200 and the dressing 102.

[0077] In some embodiments, a plenum, extended fluid pathway, or expansion chamber, such as illustrated by the inlet expansion chamber 352 and the outlet expansion chamber 354 associated with the pneumatic coupler 306 can reduce pressure peaks of air flow, reducing the sound and/or noise level of an apparatus without significantly increasing the size or cost of an apparatus. Baffles, sound absorbing foam, or both may additionally or alternatively be used to reduce the sound and/or noise level.

[0078] For example, positive pressure fluid flow from an outlet port of the pressure source 302 may enter the outlet expansion chamber 354 of the pneumatic coupler 306 through the source outlet port 344. Within the outlet expansion chamber 354, sound waves may be reflected and interfere with each other, creating a noise cancelling effect for reducing sound levels before leaving the outlet expansion chamber 354 through the mount outlet port 346 of the pneumatic coupler 306. In an analogous manner, negative pressure fluid flow may be drawn into the inlet expansion chamber 352 from the mount inlet port 342 of the pneumatic coupler 306 and toward an inlet port of the pressure source 302 fluidly coupled to the source inlet port 340 of the pneumatic coupler 306. Noise cancellation and sound reduction may similarly occur within the inlet expansion chamber 352 as previously described for the outlet expansion chamber 354. As described herein, the multi-function mount 310 and the pneumatic coupler 306 may provide a beneficial reduction in operational noise, simplified pneumatic connections, and simplified assembly for the therapy unit 200 within the therapy system 100.

[0079] In many conventional applications, the therapy system 100 may be configured to provide an alert or warning to an operator, e.g., a patient or clinician, of an undesirable event and/or the possible occurrence of an undesirable event such as, for example, a pressure leak in the system, an overpressure, pressure blockages, and a low battery condition, i.e., alarm conditions, by means of a visual display, such as the user interface 204, and/or an audible alarm generated by a built-in speaker (not shown) which may be, for example, integrated into the enclosure 202 of the therapy unit 200. However, most speakers are expensive, take up space, and include a permanent magnet that produces a strong magnetic field that may interfere with and adversely affect the operation of other medical devices in proximity to the therapy unit 200 whether or not the pressure source 302 is in an operational mode. Therefore, there is a need for improved therapy units that are capable of generating audible alarms or alerts signals without the need for a built-in speaker or an attached speaker that produces electromagnetic interference signals.

[0080] As indicated above, the pressure source 302 may be a reciprocating pump comprising a motor and a pump assembly, wherein the motor may be a brushless DC motor having a rotor that is adapted to operatively engage the diaphragm to generate negative pressure during the operational modes of the pressure source 302. In some embodiments, a pulsed voltage may be applied to the brushless DC motor so that the DC motor vibrates without the rotor rotating in an alarm mode to generate an acoustic alarm and/or a haptic alarm when an alarm condition is detected by the therapy unit 200 within the therapy system 100. It is to be understood that the components intended to dampen the operational vibrations described above are also configured not to dampen the vibrations generated by the DC motor that are desired when in the alarm mode, i.e., alarm vibrations. Rather, the components in some embodiments may be mechanically coupled within the therapy unit 200 to propagate the alarm vibrations through the enclosure 202 thereby generating an acoustic alarm and/or a haptic alarm.

[0081] In some embodiments, the pressure source 302 and the control board 304 may be modified to interface within a therapy unit 200 to generate the alarms described above. More specifically, Figure 8 is a simplified functional block diagram of an exemplary embodiment of a brushless DC pump system 800 configured to generate an acoustic alarm and/or a haptic alarm according to the principles of this disclosure. The DC pump system 800 is contained within the enclosure 202 of the therapy unit 200. The pump system 800 comprises a DC power supply 810 (e.g., a battery), a bipolar (PNP) power transistor 820, brushless direct current (DC) pump 830, bias resistor 840, and motor control unit (MCU) 850. The DC power supply 810 may correspond to the power source 308 and DC pump 830 may correspond to pressure source 302 in Figure 3. The MCU 850, bias resistor 840, and power transistor 820 may be implemented on the control board 304 in Figure 3.

[0082] The output of the MCU 850 is a pulse-width modulated (PWM) signal having an adjustable frequency and an adjustable pulse-width that drives the base of power transistor 820. For a given pulse amplitude, adjusting the pulse-width also adjusts the duty cycle of the PWM signal, thereby controlling the effective DC voltage and power delivered to the DC pump 830. The MCU Control signal on the input of the MCU 850 controls the frequency and pulse width of the PWM signal.

[0083] The DC pump 830 comprises a DC motor, an internal chamber, and a diaphragm associated with the internal chamber. The DC motor drives the diaphragm through, for example, a gear linkage. The motion of the diaphragm alternately draws fluid into the internal chamber through an inlet ofthe DC pump 830 and forces fluid outofthe internal chamber through an outlet. An external controller (not shown) on control board 304 (or elsewhere) provides the MCU Control signal. In normal operating mode, the external controller uses the MCU Control signal to turn the pump system 800 ON and OFF and to adjust the frequency and the pulse width of the PWM signal. In an alarm mode, the external controller uses the MCU Control signal to cause the DC pump 830 to vibrate without turning the DC pump 830 over (i.e., DC pump 830 is OFF). In this manner, the DC pump 830 generates an audible alarm and/or haptic alarm when an alarm condition is detected, even though the pump is OFF and not pumping fluid.

[0084] The bias resistor 840 couples the output of the MCU 850 to the base of power transistor 820. In the exemplary embodiment, the output of the MCU 850 is an active low signal. Thus, when the pump system 800 is not operating (OFF), the output of MCU 850 is high, power transistor 820 is OFF, and the voltage on the DC pump 830 is zero volts (i.e., V_pump = 0 V). When the output of the MCU 850 goes low, power transistor 820 turns ON, and the voltage on the DC pump 830 rises to a maximum value approximately equal to the VDC battery supply voltage. Therefore, the V_pump signal is always the inverse of the PWM signal at the output of the MCU 850.

[0085] If the output of the MCU 850 is simply held low, the V_pum_P signal will stay at a maximum voltage approximately equal to VDC and the DC pump 830 will be driven at maximum power and speed. However, by pulsing the output of the MCU 850 with a selected duty cycle, the amount of power delivered to the DC pump 830 may be adjusted so that the DC pump 830 rotates at a desired speed and the flow rate of the DC pump 830 is similarly adjusted.

[0086] Figure 9A and 9B illustrate exemplary PWM signals having selected duty cycles. The exemplary PWM signals represent the positive-going pulses on DC pump 830 (i.e., V_pumP). Again, it is noted that the output of the MCU 850 is the inverse of V_pumP signal. Therefore, the corresponding output of the MCU 850 would be negative-going pulses. In Figure 9A, the PWM signal may have, for example, a 40 KHz frequency (period (T) = 25 microseconds) and a pulse width of 2.5 microseconds, resulting in a 10% duty cycle. The positive-going pulses rise from 0 volts to a VMAX value close to VDC· Thus, the 10% duty cycle provides an effective DC voltage that is 10% of VMAX, as indicated by dotted line 910. In Figure 9B, the PWM signal may have, for example, a 40 KHz frequency (T = 25 microseconds) and a pulse width of 12.5 microseconds, resulting in a 50% duty cycle. The positive-going pulses rise from 0 volts to a VMAX value close to VDC· Thus, the 50% duty cycle provides an effective DC voltage that is 50% of VMAX, as indicated by dotted line 950.

[0087] According to the principles of the disclosure, the DC motor in the DC pump 830 will not rotate unless a minimum threshold DC voltage is applied to DC pump 830. The minimum threshold DC voltage may require, for example, a 60% duty cycle. For duty cycles below that level (e.g., 10%, 50%), the DC motor will not rotate, but will produce a vibration of the housing (i.e., enclosure 202) in which DC pump 830 is disposed. The patient or clinician may hear this vibration as an audible signal and/or feel the vibration as a haptic signal. The frequency and volume at which the DC motor vibrates will depend on the type and size of the DC motor, as well as the load on the DC motor.

[0088] However, for a given DC motor and load, it is possible to control the volume and the tone (or frequency) of the audible signal by continuously varying the width of the pulses applied to the DC motor. This effectively applies a pulse-width modulated (PWM) signal to the DC motor in DC pump 830. For example, a PWM signal having a “base” 40 KHZ frequency may be applied to the DC motor. The duty cycle (i.e., pulse widths) may then be varied between 10% and 20% at, for example, a 4 KHZ rate. This would produce a first audible signal having a first (and lower) frequency (or tone) of 4 KHZ at a first (and lower) volume (dB level). The duty cycle may then be varied between 25% and 35% at, for example, a 6 KHZ rate. This would produce a second audible signal having a second (and higher) frequency (or tone) of 6 KHZ at a second (and higher) volume (dB level). Thus, increasing or decreasing the duty cycle increases or decreases the volume of the audible signal while increasing or decreasing the speed at which the duty cycle varies increases or decreases the tone of the audible signal.

[0089] The circuit in Figure 8 is exemplary only and may be replaced by alternative circuit configurations that provide similar functionality. By way of example, in an alternative embodiment, the power input of the DC pump 830 may be directly coupled to DC power supply 810 and the ground of the DC pump 830 may be indirectly coupled to ground by an NPN power transistor 820. In such a configuration, the output of the MCU 850 would be an active high signal that would pulse high to turn ON the NPN power transistor 820.

[0090] Figure 10 is a flow diagram illustrating the operation of the brushless DC pump system 800. Initially, the brushless DC pump system 800 is in normal Operating Mode in which the DC pump 830 pumps fluid at a flow rate determined by the selected frequency and selected duty cycle of the PWM output of the MCU 850. At some point, such as when the brushless DC pump system 800 has completed pumping fluid, the external controller will turn OFF the brushless DC pump system 800 using the MCU Control signal.

[0091] Thus, at 1005, the brushless DC pump system 800 will exit the normal Operating Mode and will enter the Alarm Mode in which the DC pump 830 is OFF. However, during Alarm Mode, the MCU 850 may receive one or more types of alarm signals (e.g., a seal leak, a low battery, overpressure, etc.) from external sensors. For example, at 1010, the MCU 850 detects a Sensor Input signal indicating that there is a fluid leak. In order to alert the operator of the alarm condition, at 1015, the MCU 850 sets the PWM duty cycle and the PWM frequency to predetermined values that are not sufficient to turn ON the DC pump 830, but are sufficiently strong to cause the DC pump 830 to vibrate at a noticeable audible level or haptic level. Thus, at 1020, vibrating the motor of the DC pump 830 at an audible frequency will essentially turn the DC pump 830 and the housing (i.e., enclosure 202) into a speaker without the need for a separate audio speaker containing a large magnet. At 1025, this pulsing or vibration generates an audible external alarm outside of the housing (i.e., enclosure 202) of the negative- pressure therapy device that alerts the operator to the alarm condition (i.e., the fluid leak).

[0092] While shown in a few illustrative embodiments, a person having ordinary skill in the art will recognize that the systems, apparatuses, and methods described herein are susceptible to various changes and modifications. Features may be emphasized in some example embodiments while being omitted in others, but a person of skill in the art will appreciate that features described in the context of one example embodiment may be readily applicable to other example embodiments. Moreover, descriptions of various alternatives using terms such as “or” do not require mutual exclusivity unless clearly required by the context, and the indefinite articles "a" or "an" do not limit the subject to a single instance unless clearly required by the context.

[0093] The appended claims set forth novel and inventive aspects of the subject matter described above, but the claims may also encompass additional subject matter not specifically recited in detail. For example, certain features, elements, or aspects may be omitted from the claims if not necessary to distinguish the novel and inventive features from what is already known to a person having ordinary skill in the art. Features, elements, and aspects described herein may also be combined or replaced by alternative features serving the same, equivalent, or similar purpose without departing from the scope of the invention defined by the appended claims.

Claims

CLAIMS What is claimed is:

1. A medical therapy device comprising: a housing; a DC pump disposed within the housing and configured to pump a fluid into and out of an internal chamber; and a motor control unit disposed within the housing and configured to control the operation of the DC pump, wherein: in a normal operating mode, the motor control unit causes the DC pump to rotate and to pump the fluid into and out of the internal chamber; and in an alarm mode, the motor control unit causes the DC pump to vibrate without rotating, the vibration of the DC pump generating an alarm signal that may be sensed outside of the housing by an operator.

2. The medical therapy device of claim 1, wherein the motor control unit generates a pulse-width modulated (PWM) signal that drives the DC pump.

3. The medical therapy device of claim 2, wherein, in the normal operating mode, a duty cycle of the PWM signal generates a first effective DC voltage that exceeds a minimum threshold level sufficient to cause the DC pump to rotate.

4. The medical therapy device of claim 3, wherein, in the alarm mode, the duty cycle of the PWM signal generates a second effective DC voltage that does not exceed the minimum threshold level sufficient to cause the DC pump to rotate.

5. The medical therapy device of claim 4, wherein, in the alarm mode, the second effective DC voltage is sufficient to cause the DC pump to vibrate.

6. The medical therapy device of claim 5, wherein, in the alarm mode, the second effective DC voltage causes the DC pump to vibrate at an audible frequency that may be heard by the operator.

7. The medical therapy device of claim 5, wherein, in the alarm mode, the second effective DC voltage causes the DC pump to vibrate such that a haptic alarm is generated that may be felt by the operator.

8. The medical therapy device of claim 1, wherein the motor control unit is configured to receive a first control signal, wherein, in response to the first control signal, the motor control unit enters the normal operating mode.

9. The medical therapy device of claim 8, wherein the motor control unit is further configured to receive a second control signal, wherein, in response to the second control signal, the motor control unit enters the alarm mode.

10. The medical therapy device of claim 9, wherein the first and second control signals are received from an external source associated with the medical therapy device.

11. The medical therapy device of claim 1, wherein the motor control unit is configured to receive at least one alarm signal during the alarm mode and, in response to the at least one alarm signal, the motor control unit causes the DC pump to vibrate without rotating.

12. The medical therapy device of claim 11, wherein the at least one alarm signal is received from at least one sensor associated with the medical therapy device.

13. The medical therapy device of claim 12, wherein the at least one alarm signal indicates that the at least one sensor has detected a seal leak.

14. The medical therapy device of claim 12, wherein the at least one alarm signal indicates that the at least one sensor has detected a low battery level.

15. The medical therapy device of claim 12, wherein the at least one alarm signal indicates that the at least one sensor has detected an overpressure condition.

16. A medical therapy device comprising: a pump configured to pump fluid; and a motor control unit configured to control the operation of the pump, wherein the motor control unit causes the pump to vibrate without pumping fluid, the vibration of the pump generating an alarm signal that may be sensed by an operator.

17. The medical therapy device of claim 16, wherein the motor control unit causes the pump to vibrate without pumping fluid in an alarm mode.

18. The medical therapy device of claim 17, wherein the motor control unit causes the pump to pump fluid in a normal operating mode.

19. The medical therapy device of claim 18, wherein the pump is a brushless direct current (DC) pump.

20. The medical therapy device of claim 19, wherein the motor control unit generates a pulse-width modulated (PWM) signal that drives the DC pump, wherein a duty cycle of the PWM signal causes the DC pump to pump fluid in the normal operating mode and causes the DC pump to vibrate without pumping fluid in the alarm mode.