News Column

Researchers Submit Patent Application, "Impeller and Motor Assembly", for Approval

August 28, 2014



By a News Reporter-Staff News Editor at Politics & Government Week -- From Washington, D.C., VerticalNews journalists report that a patent application by the inventors Bothma, Johannes Nicolaas (Otorohanga, NZ); Bent, Scott (Auckland, NZ); Darby, Adam John (Auckland, NZ), filed on July 13, 2012, was made available online on August 14, 2014.

The patent's assignee is Fisher & Paykel Healthcare Limited.

News editors obtained the following quote from the background information supplied by the inventors: "This invention relates to a gases supply and gases humidification apparatus, particularly but not solely for providing respiratory assistance to patients or users who require a supply of gas for the treatment of diseases such as Obstructive Sleep Apnea (OSA), snoring, or Chronic Obstructive Pulmonary Disease (COPD) and the like. In particular, this invention relates to a compressor or blower for use in a gases supply apparatus which in use is integral with the gases supply apparatus.

"Devices or systems for providing a humidified gases flow to a patient for therapeutic purposes are well known in the art. Systems for providing therapy of this type, for example CPAP therapy, have a structure where gases at the required pressure are delivered from a blower (also known as a compressor, an assisted breathing unit, a fan unit, a flow generator or a pressure generator) to a humidifier chamber downstream from the blower. As the gases are passed through the heated, humidified air in the humidifier chamber, they become saturated with water vapour. The gases are then delivered to a user or patient downstream from the humidifier, via a gases conduit.

"Humidified gases can be delivered to a user from a modular system that has been assembled from separate units (that is, a system where the humidifier chamber/heater and the breathing unit/blower are separate items) connected in series via conduits. A schematic view of a user 1 receiving air from a modular assisted breathing unit and humidifier system (together or separately a 'breathing assistance apparatus') is shown in FIG. 1. Pressurised air is provided from an assisted breathing unit or blower 2a via a connector conduit 10 to a humidifier chamber 4a. Humidified, heated and pressurised gases exit the humidifier chamber 4a via a user conduit 3, and are provided to the patient or user 1 via a user interface 5.

"It is becoming more common for integrated blower/humidifier systems to be used. A typical integrated system ('breathing assistance apparatus') consists of a main blower or assisted breathing unit which provides a pressurised gases flow, and a humidifier unit that mates with or is otherwise rigidly connected to the blower unit. This mating occurs for example by a slide-on or push connection, so that the humidifier is held firmly in place on the main blower unit. A schematic view of the user 1 receiving air from an integrated blower/humidifier unit 6 is shown in FIG. 2. The system operates in the same manner as the modular system shown in FIG. 1, except that humidifier chamber 4b has been integrated with the blower unit to form the integrated unit 6.

"The user interface 5 shown in FIGS. 1 and 2 is a nasal mask, covering the nose of the user 1. However, it should be noted that in systems of these types, a mask that covers the mouth and nose, a full face mask, a nasal cannula, or any other suitable user interface could be substituted for the nasal mask shown. A mouth-only interface or oral mask could also be used. Also, the patient or user end of the conduit can be connected to a tracheostomy fitting, or an endotracheal intubation.

"U.S. Pat. No. 7,111,624 includes a detailed description of an integrated system. A 'slide-on' water chamber is connected to a blower unit in use. A variation of this design is a slide-on or clip-on design where the chamber is enclosed inside a portion of the integrated unit in use. An example of this type of design is shown in WO 2004/112873, which describes a blower, or flow generator 50, and an associated humidifier 150.

"For these systems, the most common mode of operation is as follows: air is drawn by the blower through an inlet into the casing which surrounds and encloses at least the blower portion of the system. The blower (controlled by a microcontroller, microprocessor or similar) pressurises the air stream from the flow generator outlet and passes this into the humidifier chamber. The air stream is heated and humidified in the humidifier chamber, and exits the humidifier chamber via an outlet. A flexible hose or conduit is connected either directly or indirectly to the humidifier outlet, and the heated, humidified gases are passed to a user via the conduit. This is shown schematically in FIG. 2.

"Impeller type fans or blowers are most commonly used in breathing systems of this type. An impeller blade unit is contained within an impeller housing. The impeller blade unit is connected to a drive of some form by a central spindle. A typical impeller housing is shown in FIGS. 3 and 4. A typical rotating impeller unit 54, having a plurality of blades 151 and a shroud 152, which in use is located inside the housing is shown in FIGS. 5 and 6. Air is drawn into the centre of the impeller unit through an aperture, and is then forced outwards from the centre of the housing towards an exit passage (usually located to one side of the housing) by the blades of the rotating impeller unit.

"Generally, domestic users receive treatment for sleep apnea or similar. It is most common for a nasal mask, or a mask that covers both the mouth and nose, to be used. If a nasal mask is used, it is common to strap or tape the mouth closed, so that the use of the system is effective (mouth leak and the associated pressure drop are substantially reduced or eliminated). For the range of flows dictated by the user's breathing, the CPAP device pressure generator provides a flow of gases at a substantially constant pressure. The pressure can usually be adjusted before use, or during use, either by a user, or a medical professional who sets up the system. Systems that provide variable pressure during use are also known--for example BiPAP machines that provide two levels of pressure: One for inhalation (IPAP) and a lower pressure during the exhalation phase (EPAP). Variable pressure or constant pressure systems are all 'breathing assistance apparatus'"

As a supplement to the background information on this patent application, VerticalNews correspondents also obtained the inventors' summary information for this patent application: "It is an object of the present invention to provide an improved impeller or blower/compressor for use with a breathing assistance apparatus or an improved breathing assistance apparatus.

"In one aspect the present invention may be said to consist in a breathing assistance apparatus comprising: a pressurised gases source comprising: a gases inlet, a gases outlet adapted to emit pressurised gases to an outlet of the breathing assistance apparatus, and a lightweight impeller.

"Preferably lightweight impeller is shroudless or otherwise has reduced material.

"Preferably lightweight impeller is formed in one piece.

"Preferably the lightweight impeller has a radius of between 15 and 60 mm.

"Preferably the lightweight impeller has a mass of less than 2 grams and preferably between 0.8 and 1.8 grams.

"Preferably the lightweight impeller has a pressure to inertia to radius ratio greater than 50:1 Pa per gram*mm, and preferably greater than 80:1 Pa per gram*mm.

"Preferably the lightweight impeller has a moment of inertia to radius ratio less than 15 g*mm and preferably within the range of 8 to 12 g*mm.

"Preferably the lightweight impeller has a blade sweep volume to a blade volume ratio of 16:1 or greater.

"Preferably the impeller is a centrifugal impeller rotatable about a central axis.

"Preferably the breathing assistance apparatus comprises a motor for driving the impeller wherein the motor is operated using field oriented control.

"Preferably the gases source further comprises a housing having upper and lower internal surfaces that enclose the impeller, and wherein the impeller has a plurality of blades that are substantially open to the upper and lower internal surfaces of the housing by virtue of being shroudless.

"Preferably the housing forms part of or is integrated with the breathing assistance apparatus.

"Preferably the gases source further comprises a partition to define first and second interior regions within the housing, wherein the first and second regions are fluidly connected by an opening formed in or by the partition.

"Preferably the opening formed in or by the partition is at least partially circumferential.

"Preferably opening formed in or by the partition is crescent shaped.

"Preferably the first region is defined by the housing and the partition and comprises the gases inlet.

"Preferably the second region is defined by the housing and the partition and comprises the gases outlet.

"Preferably the impeller has an axis of rotation, the partition extending radially from the axis of rotation.

"Preferably the housing further comprises a volute in the second region.

"Preferably the opening is proximate the periphery of the volute.

"Preferably the impeller is located within the first region.

"Preferably a distal end of the impeller blades curve in the direction of blade rotation.

"Preferably the breathing assistance apparatus further comprises a motor,

"the motor comprising: a rotatable shaft located within a stator, and at least one bearing structure to support the rotatable shaft within the stator, the bearing structure having one or more bearing mounts.

"Preferably the bearing mount provides compliant support to the rotatable shaft.

"Preferably an outer portion of the one or more bearing mounts engages the stator and/or a stator frame and/or other structure.

"Preferably an outer portion of the one or more bearing mounts engages the stator and/or frame of the stator.

"Preferably the stator comprises a stator frame, an inner surface of the stator frame engages with the bearing structure.

"Preferably the bearing structure further comprises one or more bearings supported by the bearing mounts about the axis of the rotatable shaft.

"Preferably the pressurised gases source has a housing and the breathing apparatus further comprises a motor mount that couples the stator and the housing to provide compliant support to the motor.

"Preferably the bearing mount and/or motor mount are flexible and/or resilient.

"Preferably the volute has a tongue at least partially defining a transition between the volute and the gases outlet, the tongue located in the second interior region.

"Preferably the bearing mounts have a curved annular body and when engaged with the stator and/or stator frame and/or other structure the annular body is coerced into an engaged configuration that provides preload to the one or more bearings.

"Preferably the bearing mount is made from a material that provides resilience and/or flexibility to provide preload when in the engaged configuration.

"Preferably the bearing mounts are made from a material that provides damping.

"Preferably the motor is operated using field oriented control.

"In another aspect the present invention may be said to consist in a breath assistance apparatus comprising: a motor comprising a rotatable shaft located within a stator, a bearing structure to support the rotatable shaft in the stator, the bearing structure having one or more bearing mounts.

"Preferably the bearing mounts provide compliant support to the rotatable shaft.

"Preferably an outer portion of the one or more bearing mounts engages the stator and/or a stator frame and/or other structure.

"Preferably the stator comprises a stator frame, an inner surface of the stator frame engaging with the bearing structure.

"Preferably the bearing structure further comprises one or more bearings supported by the bearing mounts about the axis of the rotatable shaft.

"Preferably the bearing mount is flexible and/or resilient.

"Preferably the bearing mounts have a curved annular body and when engaged with the stator and/or stator frame and/or other structure the annular body is coerced into an engaged configuration that provides preload to the one or more bearings.

"Preferably the bearing mount is made from a material that provides resilience and/or flexibility to provide preload when in the engaged configuration.

"Preferably the bearing mounts are made from a material that provides damping.

"In another aspect the present invention may be said to consist in a pressurised gases source comprising: a centrifugal impeller driven by a motor within a housing, the housing having a gases inlet, a gases outlet and a partition to define first and second interior regions wherein the first and second regions are fluidly connected by an opening in the partition.

"Preferably the first region is defined by the housing and the partition and comprises the gases inlet.

"Preferably the second region is defined by the housing and the partition and comprises the gases outlet.

"A pressurised gases source according to any of the above used in a breathing assistance apparatus according to any of the above.

"In another aspect the present invention may be said to consist in a breathing assistance apparatus comprising: a pressurised gases source comprising: a housing a gases inlet,

"a gases outlet adapted to emit pressurised gases to an outlet of the breathing assistance apparatus, a motor with a rotatable shaft and at least one bearing structure to support the rotatable shaft within a stator, the bearing structure having one or more flexible and/or resilient bearing mounts to provide compliance and/or preload and/or damping for the rotatable shaft, a lightweight impeller coupled to the rotatable shaft, a flexible and/or resilient motor mount that couples the stator and the housing to provide compliance and/or damping for the motor a partition to define first and second interior regions within the housing, wherein the first and second regions are fluidly connected by a crescent shaped opening formed in or by the partition.

"Preferably the lightweight impeller is shroudless or otherwise has reduced material.

"Preferably the lightweight impeller is formed in one piece.

"Preferably the lightweight impeller has a radius of between 15 and 60 mm.

"Preferably the lightweight impeller has a mass of less than 2 grams and preferably between 0.8 and 1.8 grams.

"Preferably the lightweight impeller has a pressure to inertia to radius ratio greater than 50:1 Pa per gram*mm, and preferably greater than 80:1 Pa per gram*mm.

"Preferably the lightweight impeller has a moment of inertia to radius ratio less than 15 g*mm and preferably within the range of 8 to 12 g*mm.

"Preferably the lightweight impeller has a blade sweep volume to a blade volume ratio of 16:1 or greater.

"In another aspect the present invention may be said to consist in a pressurised gases source comprising: a gases inlet, a gases outlet, a motor with a shaft, and a lightweight impeller connected to the motor and rotatable to draw gases from the inlet and emit gases through the outlet, wherein the impeller is shroudless or otherwise has reduced material.

"Preferably the impeller is a centrifugal impeller rotatable about a central axis.

"Preferably the gases source further comprises a housing having upper and lower internal surfaces that enclose the impeller, and wherein the impeller has a plurality of blades that are substantially open to the upper and lower internal surfaces of the housing by virtue of being shroudless.

"Preferably the housing forms part of or is integrated with a CPAP machine.

"Preferably the gases source further comprises a partition to define first and second interior regions within the housing, wherein the first and second regions are fluidly connected by an opening formed in or by the partition.

"Preferably the opening formed in or by the partition is at least partially circumferential.

"Preferably the first interior region is defined by the housing and the partition and comprises the gases inlet.

"Preferably the second interior region is defined by the housing and the partition and comprises the gases outlet.

"Preferably the impeller has an axis of rotation, the partition extending radially from the axis of rotation.

"Preferably the housing further comprises a volute in the second region.

"Preferably the opening is proximate the periphery of the volute.

"Preferably the impeller is located within the first region.

"Preferably a distal end of the impeller blades curve in the direction of blade rotation.

"Preferably the further comprising a motor, the motor comprising: a rotatable shaft located within a stator, and at least one bearing structure to support the rotatable shaft, the bearing structure having one or more bearing mounts engaged and axially aligned with the stator to provide compliant support to the rotatable shaft.

"Preferably an outer portion of the one or more bearing mounts engages the stator.

"Preferably the stator comprises a stator frame, an inner surface of the stator frame engaging with the bearing structure.

"Preferably the bearing structure further comprises one or more bearings supported by the bearing mounts about the axis of the rotatable shaft.

"Preferably the pressurised gases source further comprises a motor mount that couples the stator frame and the housing to provide compliant support to the motor.

"Preferably the bearing mount is flexible and/or resilient.

"Preferably the volute has a tongue at least partially defining a transition between the volute and the gases outlet, the tongue located in the second interior region.

"Preferably the motor is vector controlled.

"In this specification where reference has been made to patent specifications, other external documents, or other sources of information, this is generally for the purpose of providing a context for discussing the features of the invention. Unless specifically stated otherwise, reference to such external documents is not to be construed as an admission that such documents, or such sources of information, in any jurisdiction, are prior art, or form part of the common general knowledge in the art

"The term 'comprising' as used in this specification means 'consisting at least in part of'. When interpreting each statement in this specification that includes the term 'comprising', features other than that or those prefaced by the term may also be present. Related terms such as 'comprise' and 'comprises' are to be interpreted in the same manner.

"It is intended that reference to a range of numbers disclosed herein (for example, 1 to 10) also incorporates reference to all rational numbers within that range (for example, 1, 1.1, 2, 3, 3.9, 4, 5, 6, 6.5, 7, 8, 9 and 10) and also any range of rational numbers within that range (for example, 2 to 8, 1.5 to 5.5 and 3.1 to 4.7).

BRIEF DESCRIPTION OF THE DRAWINGS

"A preferred form of the present invention will now be described with reference to the accompanying drawings.

"FIG. 1 shows a schematic view of a modular assisted breathing unit and humidifier system.

"FIG. 2 shows a schematic view of a modular assisted breathing unit and humidifier system.

"FIG. 3 shows a plan view of an example of a blower unit.

"FIG. 4 shows a side view of the blower unit of FIG. 3.

"FIG. 5 shows a profile view of an impeller.

"FIG. 6 shows another profile view of an impeller.

"FIG. 7 shows a profiled view of a gases supply unit.

"FIG. 8 shows an exploded view of the gases supply unit of FIG. 7.

"FIG. 9 shows an internal view of a gases supply unit (viewed from underneath).

"FIG. 10 shows a profiled view of the gases supply unit of FIG. 9.

"FIG. 11 shows a plan view of the top side of a blower unit of one embodiment.

"FIG. 12 shows a plan view of the bottom side of the blower unit of FIG. 11.

"FIG. 13 shows a profile view of the bottom side of the blower unit of FIG. 12

"FIG. 14A shows a plan view of the impeller with no shroud according to one embodiment.

"FIG. 15A shows a profile view of the impeller of FIG. 14a with no shroud.

"FIG. 14B shows a plan view of the impeller with reduced shroud material according to one embodiment.

"FIG. 15B shows a profile view of the impeller of FIG. 14b with reduced shroud material.

"FIG. 14C shows a plan view of the impeller with a web structure.

"FIG. 15C shows a profile view of the impeller of FIG. 14c with a web structure.

"FIG. 16 shows an exploded view of the preferred housings and impeller of one embodiment.

"FIG. 17 shows a plan view of the lower housing, partition and impeller of one embodiment.

"FIG. 18 shows a profile view of the components of FIG. 17.

"FIG. 19 shows a cross sectional view of the motor and impeller of one embodiment.

"FIG. 20 shows a motor mounting structure one embodiment.

"FIG. 21 shows the motor mounting structure with a motor and impeller of one embodiment.

"FIG. 22A is a graph of average sound pressure levels of an earlier blower unit.

"FIG. 22B is a graph of average sound pressure levels of the blower unit of the present invention.

"FIG. 23 shows the motor mounting structure with a motor and impeller of a second embodiment.

"FIG. 24 shows a stator lamination of the second embodiment.

"FIG. 25 shows a pole face of the second embodiment.

"FIG. 26 shows a bearing mount of the second embodiment.

"FIG. 27 shows a cross sectional view of the motor and impeller of the second embodiment.

"FIG. 28 shows a motor mounting structure of the second embodiment.

"FIG. 29A is a pressure response graph of an earlier blower unit.

"FIG. 29B is a pressure response graph of the blower unit of the present invention."

For additional information on this patent application, see: Bothma, Johannes Nicolaas; Bent, Scott; Darby, Adam John. Impeller and Motor Assembly. Filed July 13, 2012 and posted August 14, 2014. Patent URL: http://appft.uspto.gov/netacgi/nph-Parser?Sect1=PTO2&Sect2=HITOFF&u=%2Fnetahtml%2FPTO%2Fsearch-adv.html&r=7164&p=144&f=G&l=50&d=PG01&S1=20140807.PD.&OS=PD/20140807&RS=PD/20140807

Keywords for this news article include: Fisher & Paykel Healthcare Limited.

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