Patent Description:
The present technology relates to a blower for generating a pressure differential and/or to a pressure generating device or positive airway pressure (PAP) device. In an example, the blower may be used in a positive airway pressure (PAP) device used for the delivery of respiratory therapy to a patient. Examples of such therapies are Continuous Positive Airway Pressure (CPAP) treatment, Non-Invasive Positive Pressure Ventilation (NIPPV), and Variable Positive Airway Pressure (VPAP). The therapy is used for treatment of various respiratory conditions including Sleep Disordered Breathing (SDB) and more particularly Obstructive Sleep Apnea (OSA). However, the blower may be used in other applications (e.g., vacuum applications (medical or otherwise)).

Examples of existing motor/blower designs are described in ResMed's <CIT> and <CIT>, which are incorporated into ResMed's AutoSet CS2 and S9 series of sleep therapy products, respectively.

A need has developed in the art for blower designs that are quieter and more compact, all while retaining the same or equivalent air delivery capacity, e.g., in terms of pressure and flow. The present technology provides alternative arrangements of blowers that consider this need.

<CIT> discloses a positive airway pressure device having a casing and a blower. The blower is in the form of a centrifugal pump having a stationary portion, a rotating portion and an electric motor. The stationary portion includes an external housing and an assembly of internal flow directing components including three sets of stator components and two shields. The rotating portion comprises three impellers and a shaft adapted to be driven by the electric motor. The blower has three stages each with a corresponding impeller and set of stationary vanes and shields, and has an inlet at one end and an outlet at the other end. In the first stage of the blower, air enters the blower at the inlet and passes into the first rotating impeller where it is accelerated tangentially and directed radially outward. It then passes around the sides of the motor flowing in a spiral manner with a large tangential velocity component and also an axial component towards the first set of stator vanes in the first stator component. At the first set of stator vanes, air is directed radially inwardly towards a first orifice and thereafter onto the second stage. In the second stage, air is first accelerated tangentially by the second rotating impeller and also flows outwardly in a radial direction. Air then flows in a spiral manner with a large tangential velocity component and also an axial component passing through the gap defined by the outer edge of the corresponding shield and the inner surface of the stator component. Air then enters the second set of stator vanes formed in the second stator component and is directed radially inwardly towards a second orifice, and thereafter onto the third stage. In the third stage, the fluid flow path is similar to the fluid flow path in the second stage. Air enters the third stage via the second orifice and is accelerated tangentially and also directed outwardly in a radial direction by the third rotating impeller. Air then flows in a spiral manner with a large tangential component and also an axial component passing through the gap defined by the outer edge of the corresponding shield and the inner edge of the housing. The air then is directed by stator vanes formed in the housing towards the outlet.

According to the invention, there is provided a positive airway pressure device according to claim <NUM>. The dependent claims define embodiments of the invention. The aspects of the technology described below relate to embodiments of the invention as claimed or to embodiments that, while not forming part of the invention as claimed, may contain features present in embodiments of the invention as claimed.

An aspect of the disclosed technology relates to a blower including a housing including an inlet and an outlet, a motor to drive a rotatable shaft, first and second impellers provided to the shaft, the first and second impellers each including a plurality of impeller blades, a first stationary component provided to the housing and including stator vanes downstream of the first impeller, and a second stationary component provided to the housing and including stator vanes downstream of the second impeller. A first set of stator vanes of the first stationary component is provided around the motor and are configured and arranged to direct airflow along the motor, to de-swirl the airflow and to decelerate air to increase pressure. In an example, the first impeller is positioned on one side of the motor and the second impeller is positioned on the other side of the motor. In an example, the blower includes a third impeller and a third stationary component provided to the housing and including stator vanes following the third impeller, the third impeller and the third stationary component positioned upstream of the first impeller.

An aspect of the disclosed technology relates to a blower including a housing including an inlet and an outlet, a motor to drive a rotatable shaft, first, second, and third impellers provided to the shaft (e.g., two provided to the shaft on one side of the motor and one provided to the shaft on the other side of the motor), a first stationary component provided to the housing and including stator vanes following the first impeller, a second stationary component provided to the housing and including stator vanes following the second impeller, and a third stationary component provided to the housing and including stator vanes following the third impeller. The second stationary component is provided around the motor and the stator vanes of the second stationary component are configured and arranged to direct airflow along the motor, de-swirl the airflow, and to decelerate the air to increase pressure.

Another aspect of the disclosed technology relates to a blower including at least one impeller and a stationary component following each impeller. Each stationary component includes a plurality of vanes that provide vane passages therebetween for airflow. Each vane passage includes an expanding cross-sectional area that increases from an upstream direction to a downstream direction to increase pressure.

Another aspect of the disclosed technology relates to a PAP device including a casing and a blower provided within the casing. The casing includes at least first and second chambers and a plurality of conduits or tubes that allow air to pass from the first chamber to the second chamber. The plurality of conduits are arranged to provide acoustic impedance and flow measurement by providing a defined pressure drop. In an alternative example, the casing may include a single chamber and plurality of conduits provided between the chamber and atmosphere, e.g., combine plurality of conduits and inlet into one piece.

Another aspect of the disclosed technology relates to a blower having a reduced size compared to prior art blowers while still providing high pressures with low noise and reliability. This may be enabled by one or more of the following: (i) ensuring high static regain - by using stator vane passages that expand in cross-sectional area while they turn the flow, employing stator vanes that extend all the way to the hub to prevent swirling into the next stage, forming the stator vanes in two halves to provide for a larger number of vanes that are still moldable (e.g., <NUM>-<NUM> stator vanes utilized), using skewed leading edges to soften acoustic interactions; (ii) run at faster speeds; (iii) include third stage; (iv) increasing impeller strength by extending the blades into the hub, impeller slightly tapered to reduce turbulence, less height at the outer tips of the impeller compared to the inner region of the impeller; (v) inlet housing includes chimney to provide acoustic resistance to reduce noise emitted from inlet; and/or (vi) thermally conductive plastics used for the housing and potentially the impeller to assist with removing heat. and air recirculated between the shaft and the first set of stator vanes to assist in removing heat from bearings and shaft.

Another aspect of the disclosed technology relates to a PAP device including a casing and a blower provided within the casing. The casing includes at least one chamber and one or more inlet conduits extending at least partially into the chamber to allow ambient air to enter the chamber, e.g., while providing acoustic impedance.

Another aspect of the disclosed technology relates to a PAP device including a casing and a blower provided within the casing. The casing includes at least an inlet chamber, e.g., to attenuate airborne radiated noise, having a casing inlet and a blower inlet chamber to support an inlet end of the blower. The blower is supported by a suspension system structured to divide low and high pressure sides of the blower.

Another aspect of the disclosed technology relates to a PAP device including a casing, a blower provided within the casing, and a suspension system to support the blower within the casing. At least a portion of the suspension system includes a plurality of strap members structured to clamp to an exterior of the blower to secure the portion to the blower and secure blower components of the blower in position.

Other aspects, features, and advantages of this technology will become apparent from the following detailed description when taken in conjunction with the accompanying drawings, which are a part of this disclosure and which illustrate, by way of example, principles of this technology.

The accompanying drawings facilitate an understanding of the various examples of this technology. A positive pressure airway device according to an embodiment of the invention as claimed is shown in <FIG>, comprising a blower as shown in <FIG>. In such drawings:.

The following description is provided in relation to several examples (some of which are illustrated, some of which may not be) which may share common characteristics and features. It is to be understood that one or more features of any one example may be combinable with one or more features of the other examples. In addition, any single feature or combination of features in any of the examples may constitute additional examples.

Aspects of the technology will be described herein in its application to non-invasive ventilation (NIVV) treatment apparatus (e.g., positive airway pressure (PAP) devices), such as CPAP, but it is to be understood that aspects of the technology may have application to other fields of application where blowers are used, e.g., in both positive pressure and negative pressure applications.

In this specification, the words "air pump" and "blower" may be used interchangeably. The term "air" may be taken to include breathable gases, for example air with supplemental oxygen. It is also acknowledged that the blowers described herein may be designed to pump fluids other than air.

Also, each blower example below is described as including a three stage design. However, it should be appreciated that examples of the technology may be applied to other stage designs, e.g., one, two, four, or more stages.

<FIG> illustrate a three stage, centrifugal blower <NUM> according to an example of the technology. As described below, the blower provides a low inertia, axially symmetric, three-stage blower design. The blower is structured to provide high pressure values while maintaining a low noise and small size. In an example, the blower may be structured to provide pressurized air up to <NUM>-<NUM> cmH<NUM>O, e.g., in the range of <NUM>-<NUM> cmH<NUM>O, e.g., <NUM>-<NUM> cmH<NUM>O, <NUM>-<NUM> cmH<NUM>O.

The blower is relatively small (e.g., outer diameter of the blower may be about <NUM>-<NUM>, e.g., <NUM>-<NUM>) but minimizes the increase of rpm by providing three stages. The impellers and stator vanes of the blower are compressed axially to prevent the rotor or shaft from protruding too far. The blower has relatively low inertia (e.g., about <NUM>-<NUM>·mm<NUM>) so responds relatively quickly. In an example, the blower may be about <NUM>% smaller and about <NUM>-<NUM>% the inertia of the blower disclosed in U. Patent Publication No. <CIT>.

In an example, a three stage blower according to an example of the present technology may include an overall length of about <NUM> and a diameter of about <NUM>, and a related two stage blower according to an example of the present technology may include a length of about <NUM> and a diameter of about <NUM>. In contrast, an exemplary two stage blower such as that disclosed in U. Patent Publication No. <CIT> includes a length of about <NUM> and a diameter of about <NUM>. In an example, an impeller according to an example of the present technology includes a diameter of about <NUM> on a <NUM> diameter shaft to provide low inertia, e.g., about <NUM>-<NUM>% that of an exemplary blower such as that disclosed in U. Patent Publication No. <CIT> which includes an impeller having a diameter of about <NUM> on a <NUM> diameter shaft.

Total pressure is equal to pressure per stage times the number of stages. The pressure per stage is proportional to (impeller diameter)<NUM> × (angular velocity)<NUM>. As the impeller diameter decreases, the angular velocity (rpm) may be increased to maintain a desired pressure per stage. Alternatively, the blower may minimize the increase in angular velocity by providing extra stages, e.g., three stages.

The blower is structured to provide performance for a full range of products from continuous positive airway pressure to variable positive airway pressure, where the motor must react quickly to the patient's breathing pattern, e.g., increased speed during inspiration and reduced speed during expiration. Thus, the blower is structured to generate pressures up to <NUM>-<NUM> cmH<NUM>O (e.g., and flows up to about <NUM>/min) to allow for the high impedance of some patient circuits and different altitudes.

As illustrated, the blower <NUM> includes first and second housing parts <NUM>, <NUM>, a motor <NUM> adapted to drive a rotatable shaft of the rotor <NUM>, first and second impellers <NUM>-<NUM>, <NUM>-<NUM> provided to the rotor <NUM> and positioned on one side of the motor <NUM> and a third impeller <NUM>-<NUM> provided to the rotor <NUM> and positioned on the opposite side of the motor <NUM>. The blower includes a first stationary component <NUM>-<NUM> including stage <NUM> stator vanes and following the first impeller <NUM>-<NUM>, a second stationary component <NUM> including stage <NUM> stator vanes following the second impeller <NUM>-<NUM> and enclosing the motor <NUM>, and a third stationary component <NUM>-<NUM> including stage <NUM> stator vanes and following the third impeller <NUM>-<NUM>. Also, a suspension system (e.g., constructed of silicone) including an outlet end suspension <NUM> and an inlet end suspension <NUM> may optionally be provided to the blower <NUM>, e.g., to support the blower within the casing of a PAP device as described below. In an alternative arrangement, the suspension may be formed as a single piece that encases at least a portion of the blower.

<FIG> show alternative views of the blower <NUM> and <FIG> show alternative views of the second stationary component <NUM>. In <FIG>, the outlet end suspension <NUM> includes a more ring-shaped configuration, in contrast to the example shown in <FIG>.

In the illustrated example, the blower <NUM> includes an axial air inlet <NUM> and axial air outlet <NUM> between which are located three stages with three corresponding impellers, i.e., first and second impellers positioned on one side of the motor and a third impeller positioned on the other side of the motor. However, other suitable impeller arrangements are possible.

As described below, each stage includes an axially flat impeller (i.e., axially short or axially compact impeller, e.g., total axial height of the impeller may be about <NUM>) followed by a set of stator vanes structured to direct the air flow to the next stage (or air outlet for the third stage stator vanes). A shield <NUM> is provided between the first and third stage impellers <NUM>-<NUM>, <NUM>-<NUM> and the first and third stage stator vanes <NUM>-<NUM>, <NUM>-<NUM>, e.g., to prevent blade pass tonal noise and to constrain the air within the stator vane passages. The shield <NUM> is preferably used when radially directed stator vanes or stator vanes configured in a substantially horizontal plane are positioned below the impeller. Preferably, no shield is used when axially directed stator vanes or stator vanes configured in a substantially vertical plane are positioned below the impeller as for the second stage stator vanes <NUM>. However, a shield may be used with any stator vanes arrangement. The motor is located below the second impeller, and the second stage stator vanes are designed around and below the motor to direct the air flow in a substantially axial direction and then a radial direction to the third stage impeller below the motor and the bottom portion <NUM> of the second stage stator vanes. The second stage stator vanes are divided into two main sections, an upper section, including top and intermediate portions <NUM>, <NUM> that surround the motor and includes vanes that are arranged in a substantially vertical plane or axially directed and a lower bottom portion <NUM> positioned below the motor that includes vanes that direct the airflow in a radial direction to the next stage. The stator vanes of the bottom portion <NUM> are arranged in a generally horizontal plane or are radially directed. In the illustrated example, the first and third stage stator vanes are the same.

Also, the blower may include a single stage design, a two stage design, or four or more stage designs. For example, the blower may include a two stage variant to provide lower pressures (e.g., at <NUM> cmH<NUM>O, e.g., up to about <NUM>/min), e.g., such as for a wearable device or a snore treatment device. In one example, the two stage variant may include only stages <NUM> and <NUM> (i.e., second and third impellers) with stage <NUM> (i.e., first impeller) being removed. In this example, maintaining an impeller on each side of the motor provides better balance and further reduces the size of the blower. In an alternative example, the stage <NUM> (i.e., third impeller) may be removed. In this example, a balancing ring may be provided below the motor to correctly balance the blower.

For example, <FIG> illustrate a two stage blower <NUM> according to an example of the present technology. As illustrated, the blower includes first and second housing parts <NUM>, <NUM>, a motor <NUM> adapted to drive a rotatable shaft of the rotor <NUM>, a first impeller <NUM>-<NUM> provided to the rotor <NUM> and positioned on one side of the motor <NUM> and a second impeller <NUM>-<NUM> provided to the rotor <NUM> and positioned on the opposite side of the motor <NUM>. The blower includes a first stationary component <NUM> including stage <NUM> stator vanes and following the first impeller <NUM>-<NUM> and a second stationary component <NUM> including stage <NUM> stator vanes following the second impeller <NUM>-<NUM>. The first stationary component <NUM> is provided around the motor and the stator vanes of the first stationary component are configured and arranged to direct airflow along the motor, to de-swirl the airflow and to decelerate air to increase pressure. The first stationary component <NUM> is similar to the second stationary component <NUM> of the three stage example described herein. The vanes of the second stationary component <NUM> are similar to the vanes of the third stator vanes <NUM>-<NUM> described herein. A shield <NUM> is provided between the second stage impeller <NUM>-<NUM> and the second stage stator vanes <NUM> to prevent blade pass tonal noise and to constrain the air within the stator vane passages. Also, a suspension system (e.g., constructed of silicone) including an outlet end suspension <NUM> may optionally be provided to the blower <NUM>.

In the illustrated example, the first housing part <NUM> provides an inlet <NUM> and the second housing part <NUM> provides an outlet <NUM>. The blower is operable to draw a supply of gas into the blower through the inlet and provide a pressurized flow of gas at the outlet. The blower has axial symmetry with both the inlet and outlet aligned with an axis of the blower. In use, gas enters the blower axially at one end and leaves the blower axially at the other end.

The first housing part <NUM> includes a chimney or inlet conduit portion <NUM> provided to the inlet <NUM>. The chimney <NUM> is structured to provide acoustic resistance and reduce noise emitted from the inlet with no significant restriction to the air flow provided to the inlet. In an example, the chimney <NUM> may be formed with the first housing part <NUM> as a one-piece plastic component. Alternatively, the chimney may be overmolded to the first housing part <NUM> (e.g., chimney may be constructed of thermoplastic elastomer (TPE) or other suitable material). In an example, the first and second housing parts may be constructed from a liquid crystal polymer (LCP), or polypropylene (PP) or other acoustically dampened plastic. Also, the first and second housing parts may be relatively thin, e.g., to reduce the blower diameter, and help flow internally.

In the illustrated example, the first and second housing parts <NUM>, <NUM> are coupled to one another and cooperate to retain and maintain alignment of the first, second, and third stationary components <NUM>-<NUM>, <NUM>, <NUM>-<NUM> with one another. As best shown in <FIG>, <FIG>, and <FIG>, the second housing part <NUM> includes at least two resilient arm members <NUM> (e.g., three arm members) each including tabs <NUM>(<NUM>) adapted to engage an upper wall of the first housing part <NUM>, e.g., with a snap fit. In addition, the side wall of the first housing part <NUM> includes hook members <NUM> (e.g., three hook members) adapted to engage within respective recesses <NUM>(<NUM>) provided to the arm members <NUM> of the second housing part <NUM>, e.g., see <FIG>, <FIG>, and <FIG>. However, it should be appreciated that the first and second housing parts may be secured to one another in other suitable manners.

As best shown in <FIG> and <FIG>, the motor <NUM> includes magnet <NUM> provided to the rotor <NUM> and a stator assembly or stator component <NUM>. The stator component <NUM> includes a lamination stack <NUM> (e.g., <NUM> laminations (e.g., constructed of iron)) and a stator coil or windings <NUM> (e.g., constructed of copper) provided to the lamination stack <NUM>. In an example, the motor may spin up to <NUM>,<NUM> rpm, such as up to <NUM>,<NUM> rpm. In an example, the length of the motor may be in the range of about <NUM>-<NUM>.

In an example, one or more parameters (e.g., size, material) of the stator component and/or the windings may be adjusted to achieve desired performance (e.g., power output (e.g., speed, torque)), cost and/or size characteristics. For example, the stator component may be constructed of a sintered powder material (e.g., iron particles).

In an example, the magnet <NUM> may be constructed of different magnet materials (e.g., Neodymium (Neo), Iron Boron, Samarium Cobalt (SmCo), etc.) and different magnet grades (e.g., Neo <NUM> grade, Neo <NUM> grade, Neo <NUM> grade, Neo grade <NUM>, SmCo <NUM> grade, etc.), e.g., to achieve desired performance, blower size, and/or cost characteristics. In an example, the magnet/magnet grade selected may adjust the blower size (e.g., blower volume) for a desired blower performance (e.g., up to <NUM>-<NUM> cmH<NUM>O), e.g., higher grade magnet enhances motor performance and enables smaller blower volume and smaller blower outside diameter (e.g., smaller diameter impellers) for a desired blower performance. Also, the magnet/magnet grade selected may determine a size of the magnet (e.g., length, outside diameter) for a desired motor performance. The size of the flux getters may be adjusted to accommodate the adjusted size of the magnet.

In an example, the magnet may be constructed of a higher grade magnet material (e.g., Neo <NUM>) to provide a higher concentrated energy capability which can be converted into a higher power capability. In an example, the magnet may be constructed of Neo <NUM> permanent magnet with size and performance characteristics to provide a relative permanent magnet volume of about <NUM>-<NUM>%, e.g., <NUM>%. For example, the permanent magnet volume (magnet and rotor) may be about <NUM>-<NUM><NUM> (e.g., <NUM><NUM>) and the total motor active volume (stator and everything inside stator) may be about <NUM>-<NUM><NUM> (e.g., <NUM><NUM>) to provide a relative permanent magnet volume (permanent magnet volume to total motor active volume ratio) of about <NUM>%. Thus, the larger relative permanent magnet volume allows the motor to be smaller in size (e.g., smaller stator component thickness, smaller diameter impellers) while providing similar performance characteristics as larger motors.

In the illustrated example, the rotor <NUM> is rotatably supported by a pair of high speed bearings <NUM>(<NUM>), <NUM>(<NUM>), e.g., miniature deep groove ball bearings, that are retained or housed by a bearing tube assembly. The bearing tube assembly includes a tube portion <NUM> and end portions <NUM>, <NUM> provided to respective ends of the tube portion <NUM>. The end portions <NUM>, <NUM> are structured to retain and align the bearings <NUM>(<NUM>), <NUM>(<NUM>) that rotatably support the rotor <NUM>. In the illustrated example, the end portions are formed separately from the tube portion and attached thereto. In an alternative example, one or more portions of the end portions may be integrally formed in one piece with the tube portion, e.g., lower end portion formed in one piece with the tube portion with the upper end portion structured to be attached to the tube portion or vice versa.

In the illustrated example, the bearings <NUM>(<NUM>), <NUM>(<NUM>) are the same size (e.g., <NUM> ID by <NUM> OD by <NUM> high). As shown in <FIG> and <FIG>, the end portion is in the form of an adaptor <NUM> that increases the diameter of the bearing <NUM>(<NUM>) so it fits within the tube portion <NUM>. In an alternative example, the outside diameter of the bearing <NUM>(<NUM>) may be increased (e.g., to <NUM> OD) so that it may fit within the tube portion <NUM> without the use of adaptor <NUM>. That is, the bearing tube assembly may be structured to support different size bearings.

The tube portion <NUM> encloses the magnet <NUM> on the shaft <NUM> which is aligned in close proximity to the stator component <NUM> provided along an exterior surface of the tube portion <NUM>. The tube portion <NUM> is constructed of a material that is sufficiently "magnetically transparent" to allow a magnetic field to pass through it, which allows the stator component <NUM> along its exterior surface to act on the magnet <NUM> positioned within the tube portion <NUM>. Further details and examples of such arrangement are disclosed in U. Patent Publication No. <CIT>.

<FIG> show various views of blowers and blower components according to alternative examples of the present technology. For example, such figures illustrate examples of a bearing tube assembly including a lower end portion <NUM> formed in one piece with the tube portion <NUM> and an upper end portion <NUM> (e.g., also referred to as a rotor cap or end bell) provided to the lower end portion. In an example, as shown in <FIG>, the lower end portion <NUM> may include one or more stakes <NUM>-<NUM> that may be heat staked to hold the upper end portion <NUM> in place. The end portions <NUM>, <NUM> are structured to retain and align respective bearings <NUM>(<NUM>), <NUM>(<NUM>). As illustrated, the lower end portion may be overmolded to the stator component.

<FIG> illustrate a motor <NUM> according to another example of the present technology. In this example, the motor or motor module <NUM> includes a stator component <NUM> (<FIG>) with at least two separate lamination stacks <NUM>(<NUM>), <NUM>(<NUM>) separated by a spacer <NUM> (e.g., constructed of a non-conductive material such as plastic) and stator coils <NUM>(<NUM>), <NUM>(<NUM>) provided to the stators to form two stator windings. A common magnet <NUM> (e.g., <NUM> pole magnet) is provided to the rotor <NUM>, which is rotatably supported by a pair of bearings <NUM>(<NUM>), <NUM>(<NUM>) that are retained or housed by a motor housing <NUM>. Due to the ability to perform series of parallel connection of the two stator windings, the supply of DC voltage can be chosen from either <NUM> Volts or <NUM> Volts. Such motor arrangement provides a modular motor design capability, and allows use at home or on the road, e.g., for truckers using an adaptor.

The motor housing <NUM> includes first and second housing parts <NUM>(<NUM>), <NUM>(<NUM>) which are coupled to one another to enclose the motor components therewithin. Each housing part <NUM>(<NUM>), <NUM>(<NUM>) includes an end portion providing a cylindrical opening to support a respective bearing <NUM>(<NUM>), <NUM>(<NUM>). The opening of the first housing part provides a space <NUM> for a spring (e.g., crest to crest wave spring), e.g., to apply the preload force for bearings. Also, a flux getter <NUM>(<NUM>), <NUM>(<NUM>) (e.g., constructed of stainless steel) is provided between each of the bearings <NUM>(<NUM>), <NUM>(<NUM>) and the rotor magnet <NUM>, e.g., to prevent flux from coming into bearings, inducing eddy current loss, heating up the bearings and reducing efficiency.

In the illustrated example, each lamination stack <NUM>(<NUM>), <NUM>(<NUM>) (also referred to as a stator core) includes a cylindrical or ring-shaped configuration (e.g., slotless) on which the magnetic wire or coils <NUM>(<NUM>), <NUM>(<NUM>) is wound, e.g., toroidal coil. Each lamination stack <NUM>(<NUM>), <NUM>(<NUM>) includes a plurality of laminations, e.g., <NUM>-<NUM> laminations or more, that are stacked on top of one another. The number of laminations may depend on the power requirement. In an example, the lamination stack includes about <NUM>-<NUM> laminations (e.g., <NUM> laminations) that are stacked on one another and affixed to one another using adhesives, dimples or other techniques. The lamination stack may be coated and/or provided with insulators to insulate the stack from the stator coils.

The stator coils <NUM>(<NUM>), <NUM>(<NUM>) of each stator are provided as three coils C1, C2, C3 for a three phase motor, i.e., <NUM> stator coil per phase. Each stator <NUM>(<NUM>), <NUM>(<NUM>) includes three stator teeth <NUM> that extend radially outwardly from the stator. The stator teeth <NUM> space the stator coils C1, C2, C3 on each stack apart from one another and are used for the centering of the stator inside the housings.

In an example, each coil C1, C2, C3 per stator includes <NUM> layers of magnet wire L1, L2, as best shown in <FIG> and <FIG>. In the illustrated example, each coil includes magnet wire wound around the stator with <NUM> turns total, including <NUM> turns in the first, inner layer L1 and <NUM> turns in the second, outer layer L2. However, it should be appreciated that each coil may include other suitable numbers of layers (e.g., one layer, three or more layers) and each layer may include any suitable numbers of turns.

Also, as shown in <FIG>, one of the teeth <NUM> of the first stator <NUM>(<NUM>) may include a notch <NUM>(<NUM>) adapted to align with a notch <NUM>(<NUM>) provided on one of the teeth <NUM> of the second stator <NUM>(<NUM>). The notches may act as reference points to properly position and align the stator laminations during the stacking process, the stators with respect to one another and/or within the motor housing during assembly.

<FIG> illustrates another example in which the stator component includes a single lamination stack <NUM> and stator coils <NUM> provided to the stator. The lamination stack <NUM> is taller than each lamination stack <NUM> described above in <FIG>, e.g., lamination stack <NUM> includes about <NUM>-<NUM> laminations (e.g., <NUM> laminations). The stator component includes three stator coils C1, C2, C3 for a three phase motor, i.e., <NUM> stator coil per phase. The stator teeth <NUM> space the stator coils C1, C2, C3 apart from one another on the stator. Also, one of the teeth may include a notch <NUM>(<NUM>) to act as a reference point for positioning and alignment.

Similar to the above, each coil C1, C2, C3 may include <NUM> layers of magnet wire. For example, each coil may include magnet wire wound around the stator with <NUM> turns total, including <NUM> turns in the first, inner layer and <NUM> turns in the second, outer layer. However, it should be appreciated that each coil may include other suitable numbers of layers (e.g., one layer, three or more layers) and each layer may include any suitable numbers of turns.

In the illustrated example, the first, second, and third impellers <NUM>-<NUM>, <NUM>-<NUM>, <NUM>-<NUM> are the same. However, it should be appreciated that the impellers may be different for each stage.

As best shown in <FIG>, each impeller <NUM>-<NUM>, <NUM>-<NUM>, <NUM>-<NUM> includes a plurality of curved blades <NUM> provided to a disk-like shroud <NUM>. The shroud <NUM> incorporates a hub <NUM> that is adapted to receive the shaft. The blades extend from the hub towards the edge of the shroud, e.g., for strength. In the illustrated example, the impeller includes <NUM> blades. However, it should be appreciated that the impeller may include other suitable numbers of blades, e.g., <NUM> or more blades, e.g., <NUM>-<NUM> blades, <NUM> blades, <NUM> blades, <NUM> blades. For example, <FIG> and <FIG> illustrate an impeller <NUM> including <NUM> curved blades <NUM> provided to shroud <NUM>.

Each impeller may be constructed of a plastic material, e.g., polymer thermoplastic such as Polyetheretherketone (PEEK) or polycarbonate (PC) for strength and damping properties. The shroud may have a scalloped shape (not shown). The blades may be slightly tapered from the hub to the outer tip to assist in reducing turbulence and thus noise. Thus, the height of the blades is lower at the tip than at the hub. For example, an exemplary height of the blade at the hub is about <NUM>-<NUM>, e.g., <NUM>, and an exemplary height of the blade at the tip is about <NUM>-<NUM>, e.g., <NUM>. This feature assists in reducing the size of the blower. In an example, the impeller has a diameter of about <NUM>-<NUM>, e.g., <NUM>. However, it should be appreciated that other suitable dimensions are possible.

In an alternative example, as shown in <FIG> and <FIG>, an impeller <NUM> may include a set of shorter secondary blades <NUM> each positioned between adjacent primary blades <NUM> provided to shroud <NUM>. As illustrated, each short blade <NUM> extends from the edge of the shroud <NUM> and partially towards the hub <NUM>. Each short blade <NUM> may include a shape similar to the primary blades starting at the tip (impeller outside diameter) and coming back towards the hub in the range of <NUM>%-<NUM>%, such as approximately <NUM>% of the distance from the impeller outside diameter to the impeller center line. In an alternative example, each short blade may include a circular arc shape.

<FIG> show an alternative example of an impeller <NUM> including <NUM> curved blades <NUM> provided to shroud <NUM>. As illustrated, each blade <NUM> includes a smaller curvature than blades <NUM> shown in <FIG>. <FIG> shows the taper of each blade <NUM> height from the hub <NUM> to the outer tip, e.g., to assist in reducing turbulence and thus noise. Thus, the height of each blade <NUM> measured from the shroud <NUM> is larger at the hub <NUM> than the height of each blade at the outer tip. The height of each blade may be substantially constant for a first portion of the blade adjacent the hub <NUM> and then reduce in height along the blade length in a second portion that extends to the outer tip.

In the illustrated example, the first and third stationary components <NUM>-<NUM>, <NUM>-<NUM> used in stages <NUM> and <NUM> are similar to one another and include stator vanes structured to direct air flow from a tangential to radial direction and then from a radial to axial direction. These stages <NUM> and <NUM> stator vanes <NUM> are arranged in a substantially radial direction or on a substantially horizontal plane. The second stationary component <NUM> used in stage <NUM> comprises two main sections, an upper section including having stator vanes <NUM>-<NUM>, <NUM>-<NUM> and a lower bottom portion <NUM> having stator vanes <NUM>-<NUM>. The top and intermediate portions <NUM>, <NUM> are provided around the motor <NUM> and structured to direct air flow from a tangential to axial direction without an intervening radial transition, e.g., flow straightener, and creating an expanding vane passage between the stator vanes to generate pressure via static regain. The lower bottom portion <NUM> is positioned below the motor and is structured to direct air flow in a radial direction to the next stage.

In the illustrated example, as shown in <FIG>, <FIG>, <FIG>, and <FIG>, each of the first and third stationary components <NUM>-<NUM>, <NUM>-<NUM> is provided in two parts that are formed separately from one another (e.g., molded) and then assembled to one another. As illustrated, each component <NUM>-<NUM>, <NUM>-<NUM> includes a shield <NUM> that provides a first set of stator vanes <NUM>-<NUM> and a housing <NUM> that provides a second set of stator vanes <NUM>-<NUM>. When the shield <NUM> and housing <NUM> are assembled to one another, the first and second set of vanes <NUM>-<NUM>, <NUM>-<NUM> provide the full or complete set of stator vanes <NUM> (e.g., see <FIG>) and the correct expansion sizes for air flow are produced.

In the illustrated example, half of the complete set of stator vanes <NUM> are provided to the shield <NUM> and half of the complete set of stator vanes <NUM> are provided to the housing <NUM>. This construction may make the stator vanes and each part stronger and easier to mold and stiffens both parts, by having vanes on both parts, to reduce part acoustic resonances. This construction also facilitates the molding of smaller stationary components. However, it should be appreciated that the complete set of stator vanes may be split between the shield and the housing in other suitable manners.

In the illustrated example, the shield <NUM> and the housing <NUM> each include six vanes, i.e., assembled component provides a complete set of twelve stator vanes. However, the assembly component may provide other suitable numbers of stator vanes, e.g., <NUM>-<NUM> total stator vanes, e.g., <NUM>-<NUM> total stator vanes. The housing <NUM> also includes an opening <NUM> for the air to exit from the stator vanes to the next stage or the outlet.

As best shown in <FIG>, <FIG>, and <FIG>, the shield <NUM> includes a hub <NUM>, adapted to receive the rotor <NUM> therethrough, and stator vanes <NUM>-<NUM> that extend from the hub <NUM> towards the edge of the shield <NUM>. As best shown in <FIG> and <FIG>, the housing <NUM> includes a bottom wall <NUM>(<NUM>) providing an outlet opening <NUM>, an annular side wall <NUM>(<NUM>) provided to the bottom wall <NUM>(<NUM>), and stator vanes <NUM>-<NUM> that extend along the bottom wall <NUM>(<NUM>) and at least partially across the outlet opening <NUM>. As shown in <FIG>, <FIG>, <FIG> and <FIG>, when assembled, the shield <NUM> is supported on the housing stator vanes <NUM>-<NUM>, and the hub <NUM> of the shield <NUM> includes recesses <NUM>(<NUM>) adapted to receive trailing edges of the housing stator vanes <NUM>-<NUM> (e.g., see <FIG> and <FIG>) such that all the stator vanes <NUM>-<NUM>, <NUM>-<NUM> extend from the hub <NUM> towards the side wall <NUM>(<NUM>) of the housing <NUM>. Air enters the stationary component via an annular gap <NUM>-<NUM>, <NUM>-<NUM> (e.g., see <FIG>, <FIG>, <FIG>, and <FIG>) provided between the edge of the shield and the side wall of the housing. In an example, the gap is in the range of <NUM> to <NUM>, such as about <NUM>-<NUM>. However, it is to be understood that the size of the gap may vary depending on the size of the blower.

As best shown in <FIG>, each vane passage <NUM> defined between adjacent stator vanes <NUM>-<NUM>, <NUM>-<NUM> (e.g., <NUM> vane passages defined by <NUM> vanes) is structured to provide an expanding passage along the vanes, e.g., each passage increases in cross-sectional area from the inlet to the outlet of the passage. The expansion of the vane passage is to slow down or decelerate the air and increase pressure, thereby effectively harnessing the radial speed component of the airflow.

The vanes provide a smooth transition along the path of the vane for the air flow. The width and/or shape of each vane may vary to control the expansion of the air path. As noted above, the stator vanes extend all the way to the hub, e.g., to prevent swirling of the airflow into the next stage.

In an example, the total cross-sectional area of the vane passages (i.e., total of all <NUM> vane passages) start at about <NUM>-<NUM><NUM>, e.g., <NUM><NUM>, and end at about <NUM>-<NUM><NUM>, e.g., <NUM><NUM>. The area of the vanes can also be defined by the inlet area. In an example, the inlet area between the <NUM> channels defined by the stator vanes may be equivalent to the area of a circle having a diameter of about <NUM>-<NUM>, e.g., <NUM>. The vanes have a finite thickness.

As shown in <FIG>, each vane passage <NUM> includes two portions, i.e., a radial outer portion <NUM>(<NUM>) and an inner straight portion <NUM>(<NUM>). The radial outer portion includes an expanding cross-section that transitions the air from a generally tangential direction to a generally radial direction. The vanes defining each radial outer portion have a curved structure to provide the expanding air passage to slow down the airflow and allow the generation of pressure through static regain.

The inner straight portion transitions the airflow from a radial direction to an axial direction. The inner straight portions are located above the opening <NUM> to the next stage or outlet located in the housing <NUM>. The inner straight portion is structured to prevent swirling of the airflow as it enters the next stage or outlet. The vanes defining the inner straight portion are structured to bend the airflow, e.g., at a generally right angle with respect to the radial outer portion. This portion of the vane passage is not generating or increasing the pressure, just bending the airflow toward the next stage or outlet through opening <NUM>.

As shown in <FIG>, each vane passage <NUM> includes a divergence angle or angle of expansion a which is defined between the radial outer portion of adjacent vanes, i.e., measured as the angle between the tangent of one vane compared to the adjacent vane tangent. In an example, the divergence angle a is in the range of <NUM>-<NUM>°, such as <NUM>-<NUM>°, e.g., <NUM>°, <NUM>°.

As shown in <FIG>, the entry angle γ of each vane is the angle at which the airflow is required to turn to enter the vane or passage (also referred to as the leading edge angle of the vane). The angle is measured between a tangent from the shield at the tip of the vane and a tangent out from the start of the vane tip. This angle is preferably small, e.g., not too low as this may result in large frictional losses and high impedance and not too large as this may result in large pressure losses due to sudden change of direction of air flow. In an example, the entry angle γ is in the range of about <NUM>-<NUM>°, e.g., <NUM>-<NUM>°, e.g., <NUM>-<NUM>°.

In an example, the stator vanes may all have skewed or angled leading edges to soften the blade pass pressure pulses from the airflow hitting the leading edges of the stator vanes. Thus, this arrangement reduces the blade pass acoustic tones. For example, the leading edges of the stator vanes may be angled at about <NUM>°, although other angles such as <NUM>-<NUM>° may be utilized.

In an example, the stator vanes on the shield may be skewed or angled in the opposite direction from the stator vanes on the housing for manufacturing reasons. For example, as shown in <FIG>, the stator vanes <NUM>-<NUM> on the shield <NUM> may be skewed with a forward angle and the stator vanes <NUM>-<NUM> on the housing <NUM> may be skewed with a backwards angle, or vice versa. However, the stator vanes of the shield and housing may all be skewed in the same direction.

In the illustrated example, as shown in <FIG>, <FIG>, and <FIG>, the second stationary component <NUM> is provided in three parts that are formed separately from one another (e.g., molded) and then assembled to one another (e.g., mechanical interlock (e.g., tongue/groove), friction-fit, heat stake, etc.). As illustrated, the second stationary component <NUM> includes a top portion <NUM> providing a first set of stator vanes <NUM>-<NUM>, an intermediate portion <NUM> providing a second set of stator vanes <NUM>-<NUM>, and a bottom portion <NUM> providing a third set of stator vanes <NUM>-<NUM>. The first and second sets of stator vanes <NUM>-<NUM>, <NUM>-<NUM> are arranged in a substantially axial direction around the motor or in a substantially vertical plane around the motor. In contrast, the third set of stator vanes <NUM>-<NUM> are arranged in a substantially horizontal plane below the motor or in a radial direction.

The top and intermediate portions <NUM>, <NUM> cooperate to support and maintain the motor <NUM> in an operative position. In addition, the vanes <NUM>-<NUM>, <NUM>-<NUM> of the top and intermediate portions <NUM>, <NUM> cooperate to define stator vanes <NUM> structured to direct airflow in a generally axial direction down and around the motor, i.e., first set of vanes <NUM>-<NUM> define a top portion of each vane <NUM> and second set of vanes <NUM>-<NUM> define a bottom portion of each vane <NUM>. In the illustrated example, the top and intermediate portions <NUM>, <NUM> cooperate to provide six stator vanes <NUM>. However, other suitable numbers of stator vanes are possible, e.g., <NUM>-<NUM> stator vanes.

The stator vanes <NUM> are configured and arranged to collect air from the second impeller <NUM>-<NUM> and transition the airflow from a tangential direction to an axial direction without an intervening radial transition. The stator vanes <NUM> are configured and arranged to de-swirl the airflow and provide static regain to increase the pressure.

Each vane passage <NUM> defined between adjacent stator vanes <NUM> (e.g., six vane passages defined by six vanes) are structured to provide an increasing cross-sectional area that increases from the upstream direction (i.e., adjacent the second impeller <NUM>-<NUM>) to the downstream direction (i.e., towards the third impeller <NUM>-<NUM>). Thus, the ratio of the cross-section at the beginning of each vane passage to the end of each vane passage is less than <NUM>. As the cross-sectional area of each passage increases, the air is decelerated and the pressure increases.

As best shown in <FIG>, each vane <NUM> includes a leading edge portion 85a, an intermediate portion 85b, and a trailing edge portion 85c. The leading edge portion 85a extends generally tangentially from near the outer edges of the second impeller blades <NUM>-<NUM> to collect air exiting the second impeller. The intermediate portion 85b curves downwards from the leading edge portion to direct air from a tangential direction to an axial direction. The trailing edge portion 85c extends in the axial direction towards the base of the intermediate portion.

In an example, the total cross-sectional area of the vane passages (i.e., total of all six vane passages) start at about <NUM>-<NUM><NUM>, e.g., <NUM><NUM>, and end at about <NUM>-<NUM><NUM>, e.g., <NUM><NUM>.

In an example, as shown in <FIG>, the entry angle y of the airflow at the lead edge portion is about <NUM>-<NUM>°, e.g., about <NUM>°, away from horizontal or the plane of rotation of the impeller. The angle of expansion a of the vane passage is about <NUM>-<NUM>°, e.g., about <NUM>°, <NUM>°, <NUM>°, or <NUM>°.

Static regain is related to the velocity, theoretical equation: dP = air density * (V<NUM><NUM> - V<NUM><NUM>)/<NUM>, wherein V<NUM> = velocity at the start of the vane passage (this velocity is typically <NUM>-<NUM>% or <NUM>-<NUM>% of the velocity of the impeller tip speed, thus the leading edge portion of the vanes start relatively close to the impeller) and V<NUM> = velocity at the end of the vane passage. For maximum static regain: V<NUM> should be maintained high; V<NUM> should be low; transition from V<NUM> to V<NUM> should be gradual; and angle of expansion a should be smooth.

The entire length of the vanes <NUM> provided by the top and intermediate portions <NUM>, <NUM> are used for static regain down the annular gap <NUM> (e.g., see <FIG> and <FIG>) between inner and outer walls provided by the top and intermediate portions. <FIG> and <FIG> illustrate the inner walls provided by the top and intermediate portions with their outer walls removed to more clearly illustrate the vanes <NUM>.

In an example, the leading edges of the stator vanes <NUM> may be skewed or angled in plane view to reduce blade pass pressure tones. For example, all the leading edges of the stator vanes <NUM> may be skewed in the same backwards direction. <FIG> and <FIG> are exemplary views showing skewed leading edges of the stator vanes <NUM>.

Additionally, the top and/or intermediate portions <NUM>, <NUM> may be structured such that the lamination stack <NUM> of the stator component may be at least partially exposed to the flow of gas to help carry away heat produced from the motor, e.g., see <FIG> and <FIG>.

As shown in <FIG>, <FIG>, <FIG>, and <FIG>, the bottom portion <NUM> located below the motor provides stator vanes <NUM>-<NUM> to direct airflow radially to ensure that the airflow does not swirl as it enters the third stage impeller <NUM>-<NUM>. The bottom portion <NUM> includes a bottom wall <NUM>(<NUM>) providing an outlet opening <NUM>, an annular side wall <NUM>(<NUM>) provided to the bottom wall, and stator vanes <NUM>-<NUM> that extend radially along the bottom wall from the side wall to the outlet opening <NUM>. The outlet opening <NUM> allows the air to enter the third stage.

In the illustrated example, as shown in <FIG>, <FIG>, <FIG>, and <FIG>, the intermediate portion <NUM> includes stator vanes <NUM>-<NUM> that extend radially along the bottom thereof. The stator vanes <NUM>-<NUM> are aligned and cooperate with the stator vanes <NUM>-<NUM> (see <FIG>, <FIG>, <FIG> and <FIG>) of the bottom portion <NUM> to direct airflow radially towards the outlet opening <NUM>.

In an example, one or more of the housing parts and stationary components may provide structure to allow them to interlock with one another, e.g., with a snap-fit, to facilitate retention and alignment of such parts/components. In addition, a removable interlock arrangement (e.g., snap-fit) facilitates access to the impellers (e.g., see <FIG>, <FIG>, and <FIG>) during and/or after assembly, e.g., for blower balancing purposes.

For example, <FIG> shows a blower <NUM> including alternative examples of the first, second and third stationary components <NUM>-<NUM>, <NUM>, <NUM>-<NUM> as well as an alternative example of the first housing part <NUM>. The first housing part <NUM>, also referred to as an inlet portion, provides the inlet port into the blower. In this example, the first, second and third stationary components and the first housing part are interlocked with one another, e.g., via snap-fit arrangement as described below. As a result, a second housing part (as provided in the blower <NUM> described above) is not required for retention and alignment in this example.

Similar to the example described above, the first stationary component <NUM>-<NUM> includes a shield <NUM> including a first set of stator vanes <NUM>-<NUM> (e.g., see <FIG>) and a housing <NUM> including a second set of stator vanes <NUM>-<NUM> (e.g., see <FIG>). When the shield <NUM> and housing <NUM> are assembled to one another, the first and second set of vanes <NUM>-<NUM>, <NUM>-<NUM> provide the full or complete set of stator vanes <NUM> for air flow (e.g., see <FIG>). In this example, the housing <NUM> includes structure to interlock with the housing part <NUM> and the top portion <NUM> of the second stationary component <NUM>.

Specifically, one end of the housing <NUM> includes a plurality of resilient arm members <NUM>-<NUM> (e.g., three arm members as shown but may include two arm members or four or more arm members) each including an opening <NUM>(<NUM>) adapted to receive a respective tab <NUM> provided to a side of the housing part <NUM> (e.g., see <FIG>), e.g., with a snap-fit. Also, the opposite end of the housing <NUM> includes resilient a plurality of arm members <NUM>-<NUM> (e.g., three arm members as shown but may include two arm members or four or more arm members) each including an opening <NUM>(<NUM>) adapted to receive a respective tab <NUM> provided to a side of the top portion <NUM> of the second stationary component <NUM> (e.g., see <FIG> and <FIG>), e.g., with a snap-fit. <FIG> is an enlarged view showing the snap-fit engagement between the tab <NUM> and a respective opening <NUM>(<NUM>) of an arm member <NUM>-<NUM>.

Similar to the example described above, the second stationary component <NUM> includes a top portion <NUM> providing a first set of stator vanes <NUM>-<NUM> (e.g., see <FIG>), an intermediate portion <NUM> providing a second set of stator vanes <NUM>-<NUM> (e.g., see <FIG>), and a bottom portion <NUM> providing a third set of stator vanes <NUM>-<NUM> (e.g., see <FIG> and <FIG>). The top and intermediate portions <NUM>, <NUM> cooperate to support and maintain the motor <NUM> in an operative position and to provide stator vanes structured to direct airflow in a generally axial direction down and around the motor. The bottom portion <NUM> is located below the motor and provides stator vanes to direct airflow radially to ensure that the airflow does not swirl as it enters the third stage.

<FIG> shows an example of motor <NUM> along with the intermediate portion <NUM> of the second stationary component <NUM>. Similar to the example described above, the motor <NUM> includes rotor <NUM> with magnet <NUM> and a stator component <NUM>. Also illustrated is bearing <NUM> for rotatably supporting one end of the rotor, flux getters <NUM>(<NUM>), <NUM>(<NUM>), preload spring <NUM>, and printed circuit board assembly (PCBA) <NUM> to control the motor. In an example, the stator component and the PCBA may be overmolded with the intermediate portion of the second stationary component.

In this example, the bottom portion <NUM> includes structure to interlock with the intermediate portion <NUM> of the second stationary component <NUM> and the third stationary component <NUM>-<NUM>. Specifically, one end of the bottom portion <NUM> includes a plurality of resilient arm members <NUM>-<NUM> (e.g., three arm members as shown but may include two arm members or four or more arm members) each including an opening <NUM>(<NUM>) adapted to receive a respective tab <NUM>-<NUM> provided to a side-of the intermediate portion <NUM> (e.g., see <FIG>, <FIG>, and <FIG>), e.g., with a snap-fit. In an example, the top portion <NUM> may be secured to the intermediate portion <NUM> via heat staking, e.g., see <FIG> showing stakes <NUM>(<NUM>) on the intermediate portion <NUM> adapted to extend through respective openings in the top portion582 and subsequently heat staked to secure the portions to one another.

Similar to the example described above, the third stationary component <NUM>-<NUM> includes a shield <NUM> including a first set of stator vanes <NUM>-<NUM> (e.g., see <FIG>) and a housing <NUM> including a second set of stator vanes <NUM>-<NUM> (e.g., see <FIG>). When the shield <NUM> and housing <NUM> are assembled to one another (e.g., see <FIG>), the first and second set of vanes <NUM>-<NUM>, <NUM>-<NUM> provide the full or complete set of stator vanes for air flow. In this example, the housing <NUM> of the third stationary component <NUM>-<NUM> is different than the housing <NUM> of the first stationary component <NUM>-<NUM>, e.g., bottom wall <NUM>(<NUM>) supporting stator vanes <NUM>-<NUM> is recessed lower along the annular side wall <NUM>(<NUM>) of the housing than the annular wall <NUM>(<NUM>) provided along outlet. However, the shield <NUM> provided to the housings <NUM>, <NUM> are similar.

In this example, the housing <NUM> includes structure to interlock with the bottom portion <NUM> of the second stationary component <NUM>. Specifically, one end of the housing <NUM> includes a plurality of resilient arm members <NUM>-<NUM> (e.g., three arm members as shown but may include two arm members or four or more arm members) each including an opening <NUM>(<NUM>) adapted to receive a respective tab <NUM>-<NUM> provided to a side of the bottom portion <NUM> (e.g., see <FIG> and <FIG>), e.g., with a snap-fit.

<FIG> show various sub-assembly views of the blower. For example, <FIG> shows the intermediate portion <NUM> of the second stationary component <NUM> engaged with motor <NUM>, <FIG> shows the top portion <NUM> engaged with the intermediate portion <NUM> (e.g., heat staking, mechanical interlock, etc.), <FIG> shows impeller <NUM> provided to the rotor <NUM> adjacent the top portion <NUM>, <FIG> shows the first stationary component <NUM>-<NUM> and its housing <NUM> engaged with the top portion <NUM> (e.g., via snap-fit as described above), and <FIG> shows impeller <NUM> provided to the rotor <NUM> adjacent the shield <NUM> of the first stationary component <NUM>-<NUM>. <FIG> shows the third stationary component <NUM>-<NUM> in relation to the motor <NUM>, <FIG> shows impeller <NUM> provided to the rotor <NUM> adjacent the shield <NUM> of the third stationary component <NUM>-<NUM>, and <FIG> shows the third stationary component <NUM>-<NUM> engaged with the bottom portion <NUM> of the second stationary component <NUM> (e.g., via snap-fit as described above). <FIG> and <FIG> show the assembled blower <NUM> with its housing part <NUM> and first, second and third stationary components <NUM>-<NUM>, <NUM>, <NUM>-<NUM> interlocked with one another.

However, it should be appreciated that the first and second housing parts may interlocked or otherwise secured to or relative to one another in other suitable manners.

As best shown in <FIG> and <FIG>, in the first stage, air enters the blower <NUM> at the inlet <NUM> and passes into the first impeller <NUM>-<NUM> where it is accelerated tangentially and directed radially outward. Air then flows with a large tangential velocity component and also an axial component passing through the gap <NUM>-<NUM> in the first stationary component <NUM>-<NUM> (defined by the outer edge of the shield <NUM> and the side wall of the housing <NUM>). Air then enters the stator vanes <NUM> provided by the first stationary component <NUM>-<NUM> and is directed radially inwardly towards the outlet opening <NUM>, and thereafter axially onto the second stage.

In the second stage, air passes into the second impeller <NUM>-<NUM> where it is accelerated tangentially and directed radially outward. Air then flows in a spiral manner with a large tangential velocity component and also an axial component passing through the annular gap <NUM> in the second stationary component <NUM>. Air then enters the stator vanes <NUM>-<NUM>, <NUM>-<NUM> that direct the air downwardly along the motor <NUM> and de-swirl the airflow and decelerate the air to increase the pressure. Air then converges at the bottom of the second stationary component <NUM> and is directed radially inwardly by the stator vanes <NUM>-<NUM>, <NUM>-<NUM> towards the outlet opening <NUM>, and thereafter axially onto the third stage.

In the third stage, air passes into the third impeller <NUM>-<NUM> where it is accelerated tangentially and directed radially outward. Air then flows with a large tangential velocity component and also an axial component passing through the gap <NUM>-<NUM> in the third stationary component <NUM>-<NUM> (defined by the outer edge of the shield <NUM> and the side wall of the housing <NUM>). Air then enters the stator vanes <NUM> provided by the third stationary component <NUM>-<NUM> and is directed radially inwardly towards the outlet opening <NUM>, and thereafter onto the blower outlet <NUM>.

In an example, the motor may spin up to <NUM>,<NUM> rpm. Due to the small size and high speeds from the motor, heat should be removed or dissipated from the motor, e.g., to reduce the possibility of drying lubricant grease. The use of thermally conductive plastics (e.g., Cool poly D5506, D5508, LCPs (liquid crystal polymer) and GLS LC <NUM> TC LCP) for housings and/or impellers of the blower may provide some heat dissipation. Also, heat from the motor may be conducted along the shaft of the rotor to the airpath.

For example, as best shown in <FIG>, the first stationary component <NUM>-<NUM> positioned between the first and second impellers <NUM>-<NUM>, <NUM>-<NUM> may provide structure to dissipate heat. As illustrated, the hub <NUM> of the shield <NUM> of the first stationary component includes an opening <NUM>(<NUM>) to receive the shaft <NUM> therethrough, and such opening <NUM>(<NUM>) is sufficiently larger than the diameter of the shaft to provide a space between the hub <NUM> and the shaft <NUM>. This space allows heat to be removed from the shaft <NUM> due to the pressure differential generated above and below the stator vanes of the first stationary component. That is, air circulation or cooling airflow through the space assists in removing heat out of the shaft and the bearings. The arrows A1 represent the main airflow through the blower and the arrows A2 represent the cooling airflow through the space.

In an example, a suspension system is provided to the blower, e.g., to support the blower within the casing of a PAP device and/or to isolate vibration of the blower, reducing noise transmitted by vibration through the casing. The suspension system (e.g., constructed of an elastomeric material such as silicone) includes a dual suspension arrangement, i.e., a suspension located at each end of the blower, to provide seals for the airpath, isolate vibrations, and provide shock resistance. As shown in <FIG>, the suspension system includes an outlet end suspension <NUM> to support the blower adjacent the blower outlet and an inlet end suspension <NUM> to support the blower adjacent the blower inlet.

As shown in <FIG>, the outlet end suspension <NUM> (e.g., constructed of silicone or Thermoplastic elastomer (TPE)) includes a blower engaging portion <NUM>, a tube portion <NUM>, and a casing engaging portion <NUM>.

As illustrated, the blower engaging portion <NUM> is in the form of a flange that extends radially outwardly from one end of the tube portion <NUM>. The blower engaging portion is adapted to be sandwiched between the housing <NUM> of the third stationary component <NUM>-<NUM> and the second housing part <NUM> to secure the outlet end suspension to the blower.

The tube portion <NUM> provides an outlet path extending from the outlet <NUM> of the second housing part <NUM>. As illustrated, tube portion <NUM> includes an inlet end <NUM>(<NUM>) sealed against the outlet <NUM> as well as the outlet opening <NUM> of the third stationary component <NUM>-<NUM>, and outlet end <NUM>(<NUM>), e.g., see <FIG> and <FIG>. The tube portion <NUM> provides an expanding diameter or cross-section, i.e., diameter of the tube portion increases from the inlet end <NUM>(<NUM>) to the outlet end <NUM>(<NUM>). Also, a cone-shaped member <NUM> may be provided within the tube portion and includes an end adapted to engage within the hub <NUM> of the third stationary component <NUM>-<NUM>. The cone-shaped member <NUM> allows air to decelerate or diffuse more gradually as air flows through the tube portion <NUM> towards the outlet end <NUM>(<NUM>).

The casing engaging portion <NUM> extends outwardly from the opposite end of the tube portion <NUM>. As described below, the casing engaging portion <NUM> is adapted to engage the casing or chassis of a PAP device to isolate vibrations and provide shock resistance. The casing engaging portion <NUM> includes a pressure port <NUM>(<NUM>) (e.g., see <FIG>, <FIG>) for interfacing with a pressure sensor <NUM> (e.g., see <FIG>). An advantage of such arrangement is that no additional sealing component is required, i.e., a separate seal is not required between the airpath and the pressure sensor. Bellows or other compliant features may be included in the pressure port seal to aid assembly and ensure a good seal. A similar arrangement of a port and an optionally compliant seal may be implemented for any other sensor requirements, e.g., the flow sensor that straddles the flow plate following tubes <NUM> described below, a thermistor, etc..

In use, the outlet end suspension provides the following functions: vibration isolation from the PAP device casing to the blower; resist impact on shock; seal for the air path; blower clamp; and expansion outlet path of the blower.

The outlet end suspension may be secured to the blower in other suitable manners, i.e., outlet end suspension may not be clamped into the blower via blower engaging portion <NUM> described above. In an alternative example, the outlet end suspension may be structured to clamp to the outside of the blower, e.g., using one or more strap members.

For example, <FIG> illustrate another example of an outlet end suspension <NUM> provided to the blower <NUM>. The outlet end suspension <NUM> (e.g., constructed of silicone or Thermoplastic elastomer (TPE)) includes a blower engaging portion <NUM>, a tube portion <NUM>, and a casing engaging portion <NUM>.

Similar to the example described above, the tube portion <NUM> provides an outlet path extending from the outlet of the third stationary component <NUM>-<NUM>, i.e., tube portion <NUM> includes an inlet end <NUM>(<NUM>) sealed against the annular wall <NUM>(<NUM>) provided along the outlet of the third stationary component <NUM>-<NUM>. Also, similar to the example described above, the casing engaging portion <NUM> is structured to engage the casing or chassis of a PAP device to isolate vibrations and provide shock resistance.

In this example, the blower engaging portion <NUM> includes a bottom wall portion <NUM> adapted to engage the base of the blower along the third stationary component <NUM>-<NUM> and a plurality of elongated strap members <NUM> (e.g., <NUM> strap members illustrated but more or less strap members are possible, e.g., <NUM>, <NUM>, <NUM>, or more strap members) extending in an axial direction from the bottom wall portion. The strap members <NUM> are resiliently flexible so that each strap member may be stretched to engage a respective tab <NUM> (e.g., U-shaped extrusion) provided to the housing part or inlet cover <NUM> (e.g., see <FIG> and <FIG>), which pulls the housing part downwardly to secure the blower components and suspension in position. As best shown in <FIG>, the free end of each strap member includes a catch portion <NUM>-<NUM> including an opening <NUM>(<NUM>) adapted to receive a respective tab <NUM> provided to the housing part <NUM>, e.g., generally U-shaped opening to receive generally U-shaped tab. However, it should be appreciated that the strap members may be secured with the housing part in other suitable manners. In an example, each strap may have an unstretched height (i.e., as molded height) of about <NUM>-<NUM> (e.g., <NUM>) and stretched height (i.e., as installed height) of about <NUM>-<NUM> (e.g., <NUM>), e.g., strap members provide at least about <NUM>-<NUM> (e.g., at least about <NUM>) of flexibility for installation.

As shown in <FIG>, the inlet end suspension <NUM> (e.g., constructed of silicone or Thermoplastic elastomer (TPE)) includes a blower engaging portion <NUM> and a casing engaging portion <NUM>. The blower engaging portion <NUM> includes an inner end <NUM>(<NUM>) adapted to engage the upper wall and chimney portion of the first housing part <NUM> and an outer end <NUM>(<NUM>) that wraps around the side wall of the first housing part <NUM> and/or the resilient arm members of the second housing part <NUM> to secure the inlet end suspension to the blower, e.g., see <FIG> and <FIG>.

The casing engaging portion <NUM> extends outwardly from the inner end <NUM>(<NUM>) of the blower engaging portion <NUM>. The casing engaging portion <NUM> may be resiliently flexible relative to the blower engaging portion <NUM>. As described below, the casing engaging portion <NUM> is adapted to engage the casing of a PAP device to isolate vibrations, provide shock resistance, and seal the airpath.

<FIG> and <FIG> shows another example of an inlet end suspension <NUM> provided to the blower <NUM>. The inlet end suspension <NUM> is similar to that shown in <FIG> described above. In this example, the casing engaging portion <NUM> of the inlet end suspension <NUM> includes a plurality of axially extending ribs <NUM>(<NUM>) (e.g., <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or more ribs), e.g., for axial shock absorption.

In an example, a single suspension system may be provided to the blower. The single suspension system may be integrally formed as a one piece structure (e.g., molded of an elastomeric material such as silicone) structured to enclose or encase the blower. Thus, one or more functions of a suspension system may be embodied by a single (e.g., molded silicone) part. For example, the single suspension system may perform one or more of the following functions: vibration isolation from the PAP device casing to the blower; resist impact on shock; location of the blower in the casing; seal for the air path to divide the high pressure side (outlet chamber) and low pressure side (inlet chamber) of the blower; interface and seal to pressure sensor(s); interface and seal to flow sensor; and/or interfaces and seals to other sensors like a temperature sensor.

The single suspension system may include bumps on one or more outer, surfaces to provide shock absorption and axial movement. The bumps may also prevent foam, such as acoustic foam, from contacting the blower. The single suspension system may also include a shock absorption flange positioned adjacent ribs within the casing. A thickened portion of the shock absorption flange provides shock absorption in the radial direction. A membrane on the top of the single suspension system provides vibration isolation. In certain arrangements, the single suspension system may also include a chimney portion to surround the blower inlet. The single suspension system may also include one or more ports for sensors to allow sensors to be plugged into the side of the blower. For example, the single suspension system may include a pressure sensor port and two flow sensor ports. The single suspension system may also include an aperture configured to receive the wires from the motor and to provide a seal around the wires where they exit the blower.

Alternatives to sealing and sensor interfaces include over-moulded features on the casing; using a sufficiently soft/flexible casing material to connect directly to the sensors; and traditional silicone tubing connecting the sensors to features in the rigid case.

For example, <FIG> show alternative examples of sensor interfaces or ports for pressure sensors and flow sensors. In examples, the pressure port is communicated with the blower outlet chamber and oriented perpendicular to the flow. In examples, a flow port is provided on each side of the flow plate, e.g., one communicated with the inlet chamber and one communicated with the blower inlet chamber.

<FIG> shows a PAP device in which ports <NUM> are provided in an over-molded layer <NUM>-<NUM> of the casing <NUM>. <FIG> shows a port arrangement for a flow sensor <NUM> in which the PCBA <NUM> to which the flow sensor is provided is positioned at a side of the blower chamber distal to the flow plate <NUM>. As illustrated, one port <NUM>(<NUM>) is provided to the casing to communicate with the inlet chamber along the upstream side of the flow plate <NUM> and the other port <NUM>(<NUM>) is provided to the casing to communicate with the blower inlet chamber along the downstream side of the flow plate <NUM>. Also, the ports <NUM>(<NUM>), <NUM>(<NUM>) in the casing communicate with respective ports <NUM> provided in the over-molded layer <NUM>-<NUM> as described above. <FIG> shows a port arrangement for a flow sensor <NUM> in which the PCBA <NUM> to which the flow sensor is provided is positioned adjacent to the inlet chamber/blower inlet chamber on each side of the flow plate <NUM>. As illustrated, the flow ports <NUM>(<NUM>), <NUM>(<NUM>) are provided to the casing on respective sides of the flow plate <NUM>.

<FIG> show alternative examples of flow sensor interfaces provided in an over-molded layer <NUM>-<NUM> of the casing <NUM>. In <FIG>, the port <NUM> is structured to seal along an upper wall of the flow sensor <NUM>. In <FIG>, the port <NUM> is structured to seal along an upper wall and body or side wall of the flow sensor <NUM>. In <FIG>, the port <NUM> includes a gusset or spring-like arrangement to enhance flexibility and sealing with the flow sensor <NUM>. In <FIG>, the port <NUM> is provided with a shorter length to provide less creep. In <FIG>, the port <NUM> includes a bead seal <NUM>-<NUM> for sealing with the flow sensor <NUM>.

<FIG> show alternative examples of pressure sensor interfaces or seals provided between the pressure sensor <NUM> and the blower suspension <NUM> (e.g., constructed of silicone) that supports the blower within the PAP device. As illustrated the blower suspension <NUM> and/or the pressure sensor <NUM> may include structure (e.g., sealing arms, recesses, bellows arrangement) to interlock, engage, seal, or otherwise interface with one another.

<FIG> show alternative examples of sensor interfaces or seals provided to the blower suspension (e.g., one-piece suspension) that supports the blower. In <FIG>, the suspension <NUM> for blower <NUM> includes a plug-type port <NUM> adapted to be inserted into an opening provided in the blower casing <NUM>. As shown in <FIG>, the suspension along with the plug-type port may be molded flat, and then the plug-type port may be bent or flexed into engagement with the blower casing. In <FIG>, the plug-type port <NUM> extending (e.g., by thin, flexible web) from the blower suspension <NUM> may include a flange <NUM>-<NUM> (e.g., to prevent from pushing the port too far into the opening in the blower casing <NUM>) and a barb <NUM>-<NUM> (e.g., to secure the port within the opening). As illustrated, the port <NUM> provides a tapered opening into the casing and may include a gusset or spring-like arrangement to enhance flexibility and sealing with the pressure sensor <NUM> and blower casing. In <FIG>, the port <NUM> extends from the blower suspension <NUM> and includes structure <NUM>-<NUM> that interlocks or otherwise engages an exterior of the blower casing <NUM> to secure the port <NUM> and pressure sensor <NUM> in position. In <FIG>, the port <NUM> extends from the blower suspension <NUM> and includes structure <NUM>-<NUM> that interlocks or otherwise engages an interior of the blower casing <NUM> to secure the port <NUM> and pressure sensor <NUM> in position.

<FIG> shows a single suspension system <NUM> (e.g., constructed of silicone) for a blower according to an example of the disclosed technology. As illustrated, the blower includes a generally cylindrical side wall <NUM> that encloses the blower which connects by a thin web <NUM> to a thicker silicone seal <NUM> around the perimeter of the case/cover interface of the casing. The web <NUM> provides vibration isolation and divides the low and high pressure sides of the blower. Axial shock-absorbing features (e.g., bumps <NUM>) are provided at the blower outlet end of the suspension and axial and radial shock-absorbing features (e.g., flexible membrane <NUM>) are provided at the blower inlet end of the suspension.

<FIG> shows a single suspension system (e.g., constructed of silicone) including an inlet end suspension portion <NUM> and an outlet end suspension portion <NUM> that are molded in one piece and coupled to one another by connector <NUM>. In use, the blower may be provided to the portion <NUM> and then the portion <NUM> may be folded over to enclose the blower within the suspension system. As shown in <FIG>, the inlet end suspension portion may be provided as two parts <NUM>(<NUM>), <NUM>(<NUM>) that may be folded over to assemble. <NUM> PAP Device.

As described below in more detail; the PAP device or pneumatic block is configured to provide the following functions: (i) house and protect a blower located within the PAP device; (ii) form the air path from the chassis or casing air inlet to the blower and from the blower to the chassis or casing outlet; (iii) to assist in attenuating noise, including radiated and airborne or inlet noise; and/or (iv) to provide an interface for one of more of the following: sensors, printed circuit board assembly (PCBA), humidifier, air delivery tube, inlet filter and/or user interface components.

It should be appreciated that the PAP device may be used with different blowers, e.g., three-stage blower <NUM> and two-stage blower <NUM> described herein, blowers described in U. Patent Application Publication No. <CIT> and <CIT>.

However, the PAP device is according to the invention as claimed only if it falls within the scope of the claims, which is not the case if comprising the two-stage blower <NUM>.

Also, the PAP device may form part of a PAP system, e.g., PAP device or pneumatic block may be inserted into or otherwise interfaced with other components, such as a user interface, controls, and/or outer housing, to form a flow generator system. Alternatively, the PAP device, with one or more additional features, may be a stand-alone device. For example, the PAP device may be provided with one or more of the following features to provide a stand-alone device: non-rigid feet or other vibration isolation feature so that the device can be as intended when placed on a hard surface, enclosure for the PCBA, user-interface features/components, and/or filter cover. For example, <FIG> shows a PAP system including outer enclosure <NUM> for enclosing PAP device <NUM>, user interface <NUM> (e.g., screen, buttons, dial), inlet filter cover <NUM> along inlet of the PAP device, PCBA <NUM> including one or more sensors for interfacing with the PAP device. The outlet <NUM> of the PAP device extends outside the enclosure or may be coupled to an outlet port to provide an outlet connector for a mask (e.g., via air tubing) or humidifier. <FIG> shows a PAP system similar to <FIG> with the outlet of the PAP device coupled to a humidifier <NUM> (enclosed within an outer enclosure). The outlet <NUM> of the humidifier extends outside its enclosure to provide an outlet connector for a mask (e.g., via air tubing).

<FIG> and <FIG> show an example of a PAP device <NUM>, according to an embodiment of the invention as claimed, including a casing or chassis <NUM> and the blower <NUM> supported within the casing <NUM> by the suspension system. In the illustrated example, the casing <NUM> includes three different expansion chambers to provide acoustic impedance for air flowing to the inlet of the blower, i.e., a first inlet muffler chamber <NUM>(<NUM>), a second inlet muffler chamber <NUM>(<NUM>), and a blower chamber <NUM>(<NUM>). In an example, the relative volumes of the chambers may include similar or different volumes from one another, e.g., first inlet chamber <NUM>(<NUM>) may be larger than the second inlet chamber <NUM>(<NUM>). The air or gas flow between the different chambers is via at least one flow conduit or tube or pipe. There may be <NUM>, <NUM>, or more larger flow conduits or a plurality of smaller conduits or tubes as described in more detail below.

The casing may be constructed of a plastic material, polypropylene, polyamide, polybutylene terephthalate (PBT), polyethylene, polyethylene terephthalate (PET), high density polyethylene (HDPE), other semi-crystalline plastics, polycarbonate, acrylonitrile butadiene styrene (ABS), thermoset polymers (e.g., epoxy), thermoset elastomer (e.g., silicone, e.g., Shore D or above <NUM> Shore A hardness), MuCell gas-assisted microcellular injection molded foam, or thermoplastic elastomers (TPE) (e.g., Hytrel, Santoprene, TPU), or blends, alloys, or combinations thereof. However, other suitable materials are possible, e.g., metals, glasses, ceramics, hybrids). One or more surfaces or walls of the casing may be over-molded to attenuate wall-radiated noise. The over-moulding may be formed on either the inside or outside surface of the casing walls or both. For example, the casing may include a single layer material, over-molded or assembled with hard inside/soft outside, over-molded or assembled with soft inside/hard outside, or filled cavity or laminations of any combination of these materials or foam. <FIG> shows an example of a casing <NUM> including a hard base <NUM>-<NUM> for stiffness (e.g., polycarbonate, ABS) with a TPE overmold <NUM>-<NUM> for damping. The casing may also or alternatively comprise one or more flexible walls, such as a silicone wall. Also, the casing material may be formed with increased damping properties. In an example, the flexural modulus for stiffness of the casing walls may be in the range of about <NUM>-<NUM>,<NUM> MPa. In another example, the stiffness may be <NUM>-<NUM> MPa. The loss coefficient for the polymeric materials of the casing walls (not composites/metals) may be in the range <NUM> to <NUM>.

The casing may also be shaped to include a plurality of curved surfaces rather than flat surfaces to provide increased stiffness to the walls and assist in attenuating radiating noise through the casing. In particular, the chambers upstream of and/or surrounding the blower may be irregularly shaped or axially asymmetrical relative to the blower to reduce chamber resonances that may result from the air flow, thus not cylindrical. For example, the chamber walls may include a plurality of convex and/or concave surfaces. Radiated noise may be attenuated by increasing the mass, stiffness and/or damping the casing walls.

In an alternative example, the wall separating the first and second chambers <NUM>(<NUM>), <NUM>(<NUM>) may be eliminated to provide only two chambers. In such example, the length of the inlet conduits <NUM> into the first chamber <NUM>(<NUM>) (described below) may be increased. The chambers are arranged to attenuate airborne noise, i.e., to muffle the blower noise.

In an example, the PAP device includes an overall height of about <NUM>, and overall width of about <NUM>, and an overall length of about <NUM>. In an example, the volume of the PAP device is about <NUM>,<NUM><NUM>. However, the dimensions of the PAP device may be varied depending upon the type and size of the blower to be included within the PAP device. In certain arrangements, the overall height of the PAP device may be <NUM>, overall width of about <NUM>, and an overall length of about <NUM>.

<FIG> show different shapes for the inlet chamber <NUM>(<NUM>) and blower chamber <NUM>(<NUM>) according to alternative examples of the disclosed technology. As noted above, the shapes of the blower chambers may be configured to optimize: large muffler volume; small size casing; axially asymmetric blower chambers; curved walls for stiffness; space for interfacing sensors; and/or space for fastening. As described below, <FIG> and <FIG> show an arrangement where two inlet chimneys <NUM> extend into the inlet chamber, and <FIG> shows an arrangement where one inlet chimney <NUM> extends into the inlet chamber. As illustrated, the casing may provide structure (e.g., retaining ribs <NUM> as shown in <FIG> and <FIG>) to retain acoustic foam, e.g., within the blower chamber adjacent the blower inlet.

In an example, each chamber volume may be within the range of about <NUM>,<NUM>-<NUM>,<NUM><NUM>. For example, the inlet chamber volume may in the range of about <NUM>,<NUM>-<NUM>,<NUM><NUM> (e.g., <NUM>,<NUM>-<NUM>,<NUM><NUM> (e.g., <NUM>,<NUM><NUM>), <NUM>,<NUM>-<NUM>,<NUM><NUM> (e.g., <NUM>,<NUM><NUM>), <NUM>,<NUM>-<NUM>,<NUM><NUM> (e.g., <NUM>,<NUM><NUM>)), and the blower chamber volume may be in the range of about <NUM>,<NUM>-<NUM>,<NUM><NUM> (e.g., <NUM>,<NUM>-<NUM>,<NUM><NUM> (e.g., <NUM>,<NUM><NUM>), <NUM>,<NUM>-<NUM>,<NUM><NUM> (e.g., <NUM>,<NUM><NUM>), <NUM>,<NUM>-<NUM>,<NUM><NUM> (e.g., <NUM>,<NUM><NUM>). In one example, a chamber configuration for a blower includes an inlet chamber volume of about <NUM>,<NUM><NUM> and a blower chamber volume of about <NUM>,<NUM><NUM> for a total volume of about <NUM>,<NUM><NUM>. In another example, a chamber configuration for a blower includes an inlet chamber volume of about <NUM>,<NUM><NUM> and a blower chamber volume of about <NUM>,<NUM><NUM> for a total volume of about <NUM>,<NUM><NUM>. In another example, a chamber configuration for a blower includes an inlet chamber volume of about <NUM>,<NUM><NUM> and a blower chamber volume of about <NUM>,<NUM><NUM> for a total volume of about <NUM>,<NUM><NUM>. It should be appreciated that the chamber volumes may be varied depending upon the type and size of the blower to be included within the PAP device.

The first and second inlet muffler chambers <NUM>(<NUM>), <NUM>(<NUM>) are structured to attenuate airborne radiated noise. One or more inlet chimneys or conduits <NUM>, such as two or three or more (only one shown in <FIG>), extend into the first inlet muffler chamber <NUM>(<NUM>) to allow ambient air to enter the casing while providing acoustic impedance. The inlet chimney(s) <NUM> are shown arranged substantially parallel to the axis of the blower, however the inlet chimney(s) may be provided at any angle within the inlet chamber. The inlet chimney(s) <NUM> may have a generally cylindrical or tubular shape (however other suitable shapes are possible such as oval, rectangular, hexagonal, peanut-shaped, pill-shaped, etc.). A sharp entrance to the chimney(s) may result in pressure losses due to detached flow and a reduction in effective cross-sectional area.

To assist in reducing the radiated noise from the device, the inlet chimney conduit(s) are designed to have a high inertance and low flow resistance. Inertance is a measure of the pressure gradient in a fluid required to cause a change in flow-rate with time and for a circular conduit or tube is given by the formula:
<MAT>.

Wherein L is the length of the conduit or tube, p is the density of air, and A is the cross-sectional area of the conduit or tube.

The inlet chimney(s) <NUM> may have a length of approximately <NUM> to <NUM>, such as <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> or <NUM> or any number therebetween. If a single inlet chimney <NUM> is used, then a longer length chimney may be provided, such as <NUM> to <NUM>, e.g., <NUM>. The inlet chimney(s) may have an internal diameter at the exit end of approximately <NUM> to <NUM>, such as <NUM>, <NUM>, <NUM> or <NUM>. The inlet chimney(s) may taper along its length such that the diameter at the inlet end of the inlet chimney <NUM> is larger than the diameter at the exit end of the inlet chimney <NUM>, e.g., <NUM>-<NUM>° draft angle for molding purposes. The inlet chimney may be structured to be as long as possible provided it does not impede or choke the airflow at the outlet. For example, the inlet chimney may have a length greater than <NUM>% of the total length of the inlet chamber, or greater than <NUM>% of the total length of the inlet chamber or longer such as <NUM>% to <NUM>% of the total length of the inlet chamber. A longer inlet chimney has been shown to provide less radiated noise emitted from the device. For example, <FIG> is a graph showing how a longer chimney may assist in reducing noise output, e.g., <NUM> inlet chimney (shown with triangular data points) provides less noise over a greater range of frequencies than <NUM> inlet chimney (shown in square data points). The inlet chimney is configured to provide an inertance of the conduit that is greater than <NUM>/m<NUM>, or preferably greater than <NUM>/m<NUM> or more preferably greater than <NUM>/m<NUM>.

As shown in <FIG>, when two inlet muffler chambers <NUM>(<NUM>), <NUM>(<NUM>) are provided, a conduit or conduits <NUM> allows air to pass from the first inlet muffler chamber <NUM>(<NUM>) to the second inlet muffler chamber <NUM>(<NUM>). Such conduits <NUM> are not required if a single inlet muffler chamber is provided. Acoustic foam <NUM>, <NUM> may optionally be provided in one or more chambers of the PAP device to reduce noise such as provided within the first inlet muffler chamber to reduce noise.

A flow plate including an array of conduits <NUM> (e.g., molded thermoplastic) is provided within the second inlet muffler chamber <NUM>(<NUM>) to allow air to pass from the second inlet muffler chamber <NUM>(<NUM>) to the blower chamber <NUM>(<NUM>). The conduits <NUM> are structured to provide acoustic impedance as well as provide flow resistance to facilitate flow sensing or flow measurement by creating a defined pressure drop, for example a pressure drop of <NUM>-<NUM> cmH<NUM>O. The array of conduits includes multiple parallel conduits or tubes, e.g., to provide laminar flow. In the illustrated example, the array includes <NUM> total tubes arranged in <NUM> rows of <NUM> tubes (only one row shown in <FIG>). Such arrangement provides a good pressure difference signal even at low flow levels. However, it should be appreciated that the array may include other suitable numbers of conduits or tubes and arrangements, e.g., <NUM>-<NUM> tubes, such as <NUM> tubes, configured to meet the required pressure drop. The flow conduits may be arranged in one group or in multiple groups. For a casing including a plurality of inlet chimneys <NUM>, the flow conduits <NUM> may be arranged in groups to match the number of inlet chimney. For example, if two inlet chimneys are provided, then two groups of flow conduits may be provided. The flow may be arranged such that each group includes the same number of flow conduits or a different number of flow conduits: The flow conduits are not required to be arranged symmetrically or to be formed in the same plane. However, for accurate flow sensing, the flow conduits <NUM> must be arranged such that air flows evenly through the conduits. The array of conduits may be more easily manufactured than the prior art (large conduit subdivided by many thin walls, such as a honeycomb configuration). In an alternative example, the casing may include a single chamber and the array of conduits provided between the chamber and atmosphere, e.g., combine plurality of conduits and inlet into one piece.

For example, <FIG> show flow plates with alternative arrangements of flow conduits <NUM>. <FIG> show flow plates with two groups of flow conduits or tubes (one group per inlet chimney), with each group including the same number of flow conduits or tubes. In <FIG>, each group includes <NUM> rows of <NUM> tubes. In <FIG> , each group includes <NUM> rows with <NUM> of the rows including <NUM> tubes and <NUM> of the rows including <NUM> tubes, i.e., rows in each group may include different number of tubes. In <FIG>, each group includes <NUM> rows with one of the rows including <NUM> tubes and the other of the rows including <NUM> tubes. <FIG> shows a flow plate with two groups of flow conduits or tubes (one group per inlet chimney), with each group including a different number of flow conduits or tubes, e.g., one group includes <NUM> rows of <NUM> tubes and the other group includes <NUM> total tubes in an offset arrangement. <FIG> shows flow tubes having different lengths and arranged in different planes.

The length of the flow conduits may be defined to provide a high inertance to assist in reducing radiated noise in a similar manner to that described above for the inlet chimney(s). The flow conduits <NUM> may have a length of approximately <NUM> to <NUM>, such as <NUM>, <NUM>, <NUM>, <NUM> or <NUM> or any length therebetween. The flow conduits may have an internal diameter at the exit end of the conduit of approximately <NUM> to <NUM>, such as <NUM>, <NUM>, <NUM>, <NUM>, <NUM> or <NUM>. The length of each flow conduit may vary within the set of flow conduits. The flow conduits may be tapered along their length from the inlet or entry end to the exit end, such that the inlet end is larger than the exit end, e.g., <NUM>-<NUM>° draft angle for molding purposes.

In illustrated examples (e.g., see <FIG>, <FIG>, <FIG>, and <FIG>), the flow conduits are provided upstream of the blower (i.e., upstream of the blower inlet). In an alternative example, the flow conduits may be provided downstream of the blower (i.e., downstream of the blower outlet).

The blower <NUM> is supported by the outlet end and inlet end suspensions <NUM>, <NUM> within the blower chamber <NUM>(<NUM>) of the casing <NUM>. As illustrated, the resiliently flexible, casing engaging portion <NUM> of the inlet end suspension <NUM> is adapted to engage interior walls of the blower chamber to stably support the inlet end of the blower <NUM> within the blower chamber. The casing engaging portion <NUM> seals the inlet <NUM> within the blower chamber and the resiliently flexible arrangement of the casing engaging portion <NUM> isolates vibrations and provides shock resistance. Acoustic foam <NUM>, <NUM> (e.g., die cut, e.g., polyurethane foam) may also be provided within one or more chambers of the PAP device to reduce or dampen noise, such as in the blower chamber adjacent the inlet to reduce noise. In an example, as shown in <FIG>, the foam <NUM> may include one or more cut-outs <NUM>-<NUM> along its perimeter (e.g., to receive retaining ribs <NUM> as shown in <FIG> and <FIG>) for retaining and aligning the foam within chamber. In an example, foam may include a foam volume in the range of about <NUM>,<NUM>-<NUM>,<NUM><NUM> (e.g., <NUM>,<NUM>-<NUM>,<NUM><NUM> (e.g., <NUM>,<NUM><NUM>), <NUM>,<NUM>-<NUM>,<NUM><NUM> (e.g., <NUM>,<NUM><NUM>)). The size of the foam may be varied depending upon the type and size of the blower to be included within the PAP device.

The casing <NUM> includes a base <NUM>(<NUM>) (providing the inlet airpath with three chambers, inlet chimneys) and an end wall or cover <NUM>(<NUM>) provided to the base (providing airpath from blower outlet to air delivery tube or humidifier). The cover <NUM>(<NUM>) may in the form of a cup-shaped lid or include curved surfaces to increase the strength, improve sealing and/or reduce radiated noise. For example, <FIG> shows a cover <NUM>(<NUM>) including curved surfaces <NUM>(<NUM>)-<NUM>, and <FIG> shows a cover <NUM>(<NUM>) with two cup-shaped portions <NUM>(<NUM>)-<NUM> (e.g., flow tubes <NUM> may be moved closer to inlet chimney <NUM> to accommodate cover structure. <FIG> shows another example a cup-shaped cover <NUM>(<NUM>). In this example, the flow plate with flow tubes <NUM> may be provided as a separate part, and the slit line between the cover <NUM>(<NUM>) and base <NUM>(<NUM>) is provided along a middle of the case, e.g., rear suspension <NUM> for blower provides seal between base and cover. The cover <NUM>(<NUM>) may be coupled to the base <NUM>(<NUM>) using any known fastening method such as welding, heat staking, via adhesives, via screws, snaps or other such fasteners. Thus, the cover <NUM>(<NUM>) may be coupled to the base <NUM>(<NUM>) in a removable or permanent manner. The outlet end suspension <NUM> stably supports the outlet end of the blower <NUM> within the blower chamber and also provides a seal between the cover <NUM>(<NUM>) and the base <NUM>(<NUM>) of the casing <NUM>.

<FIG> show alternative examples for sealing between the cover <NUM>(<NUM>) and the base <NUM>(<NUM>). For example, <FIG> <FIG> shows a pressure-assisted seal <NUM> with relatively thin lip seals, <FIG> shows cover/base interface that is internal to the casing with optional seals <NUM>(<NUM>) and/or <NUM>(<NUM>) provided to the cover <NUM>(<NUM>) for sealing with the base, <FIG> shows cover <NUM>(<NUM>) with snap-fit tab <NUM> to secure cover to base <NUM>(<NUM>) and a seal <NUM> sandwiched between the cover and a ledge of the base <NUM>(<NUM>), <FIG> shows a cover <NUM>(<NUM>) with a barb or snap <NUM> adapted to sealingly engage within an opening provided to the base <NUM>(<NUM>), <FIG> shows a pressure-assisted seal <NUM> with cushion type or question-mark shaped seals, <FIG> shows cover <NUM>(<NUM>) with a seal <NUM> to seal with the base <NUM>(<NUM>) and a barb <NUM> for engaging blower suspension <NUM>, and <FIG> shows cover <NUM>(<NUM>) with a seal <NUM> (e.g., seal in the form of bead, lip or bellows overmolded to cover) to seal with the base <NUM>(<NUM>) and locating teeth <NUM> on the cover/base to support the blower suspension <NUM> within the casing.

As illustrated, the tube portion <NUM> of the outlet end suspension <NUM> is aligned and engaged with the outlet <NUM> provided to the end wall <NUM>(<NUM>) to seal the airpath from the blower outlet <NUM> to the casing outlet <NUM>. As illustrated, the outlet <NUM> may provide an expanding diameter which is substantially continuous with the expanding diameter of the tube portion <NUM>. However, in other configurations, the outlet <NUM> may not include an expanding cross-section. Also, it should be appreciated that the outlet <NUM> may not directly align with blower outlet <NUM>, e.g., outlet may be provided along any portion of the cover <NUM>(<NUM>), e.g., for ease of interface with a humidifier, etc. For example, <FIG> show alternative locations for an outlet on cover <NUM>(<NUM>), e.g., outlet <NUM>-<NUM>, <NUM>-<NUM>, or <NUM>-<NUM>. Moreover, the casing engaging portion <NUM> of the outlet end suspension <NUM> includes an outer wall <NUM>(<NUM>) to provide a seal between the end wall <NUM>(<NUM>) and the outer wall of the base <NUM>(<NUM>) and an inner wall <NUM>(<NUM>) to provide a seal between the end wall <NUM>(<NUM>) and an interior wall (e.g., interior chamber wall) of the base <NUM>(<NUM>). A bottom wall <NUM>(<NUM>) (e.g., with one or more openings) is provided between the outer wall <NUM>(<NUM>) and each side of the inner wall <NUM>(<NUM>), e.g., see <FIG> and <FIG>. The bottom wall <NUM>(<NUM>) may be resiliently flexible so as to support the outlet end of the blower in a vibration isolating and shock resistance manner.

A printed circuit board assembly <NUM> (PCBA) is provided to the casing <NUM> (e.g., casing including one or more legs to hold PCBA) to control the motor <NUM>. The PCBA <NUM> may include one or more sensors, e.g., pressure sensor <NUM>, flow sensor <NUM> as shown in <FIG>.

<FIG> shows a PCBA <NUM> according to an example of the present technology. In this example, the PCBA <NUM> may include a pressure sensor <NUM>, electrically erasable programmable read-only memory (EEPROM), dedicated micro controller <NUM> (e.g., provide control and/or therapy), and/or hardware fault mitigations <NUM> via programmable mixed signal chip (fewer parts, more flexible).

<FIG> shows another example of a PAP device <NUM> including casing <NUM> and blower <NUM> supported within the casing <NUM> by suspension system <NUM>. In this example, the blower is similar to that described in U. Patent Application Publication No. <CIT>, however it should be appreciated that the PAP device may be structured to support different blower designs. In this example, the casing <NUM> (including base or chassis <NUM>(<NUM>) and cover <NUM>(<NUM>)) provides two chambers, i.e., inlet chamber <NUM>(<NUM>) and blower chamber <NUM>(<NUM>). As described above, inlet conduit(s) or chimney(s) <NUM> (e.g., one <NUM> inlet chimney arranged parallel to the blower axis) extends from the inlet into the inlet chamber, and flow conduits <NUM> extend between the inlet chamber <NUM>(<NUM>) and the blower chamber <NUM>(<NUM>). In this example, the flow conduits <NUM> are provided to a similar side of the casing as the inlet chimney. Foam <NUM> is provided within the blower chamber adjacent the inlet to reduce noise. A filter interface <NUM> (e.g., wall support structure) may be provided to the inlet to support an inlet filter. As described above, the suspension system <NUM> may be in the form of a single suspension system structured to, e.g., provide a seal between the base <NUM>(<NUM>) and cover <NUM>(<NUM>), provide vibration isolation and impact resistance, and divide low pressure side <NUM>(<NUM>) and high pressure side <NUM>(<NUM>) leading to the outlet.

<FIG> shows a PAP device <NUM> similar to that shown in <FIG>. In this example, the flow conduits <NUM> are provided adjacent an outlet side of the inlet chimney(s) <NUM>. Also, a filter cover <NUM>-<NUM> is provided to the filter interface <NUM> at the casing inlet.

<FIG> show another example of a PAP device <NUM> including casing <NUM> and blower <NUM> supported within the casing <NUM> by suspension system <NUM>. The casing <NUM> (including base or chassis <NUM>(<NUM>) and cover <NUM>(<NUM>)) provide two chambers, i.e., first inlet chamber <NUM>(<NUM>) and second chamber <NUM>(<NUM>) or blower inlet chamber. The inlet chamber <NUM>(<NUM>) is relatively large compared to the second chamber <NUM>(<NUM>), e.g., to reduce noise, and the blower <NUM> encased by single, one-piece suspension system <NUM> is positioned within the inlet chamber <NUM>(<NUM>) but receives airflow at an inlet end of the blower from the second chamber <NUM>(<NUM>) or blower inlet chamber. The inlet chimney <NUM> extends from the casing inlet <NUM>(<NUM>)-<NUM> provided by the cover <NUM>(<NUM>) into the inlet chamber, and the flow plate <NUM> including flow conduits <NUM>-<NUM> is provided between the cover/base to divide the inlet chamber <NUM>(<NUM>) and the second chamber <NUM>(<NUM>). In this example, the inlet chimney and the flow conduits both extend parallel to the blower axis. Foam <NUM> may be provided within the second chamber adjacent the blower inlet. The suspension system <NUM> is in the form of a single, one-piece suspension system structured to, e.g., interlock and seal with the flow plate <NUM>, provide a silicone outlet chamber <NUM> for the blower, provide an outlet conduit <NUM> that extends through the casing outlet to outside the casing (e.g., outlet conduit is offset from blower outlet), divide low pressure side and high pressure side of blower, and provide vibration isolation and impact resistance (e.g., interior bumps <NUM> to seal, retain, and isolate vibrations).

<FIG> show another example of a casing <NUM> for a PAP device including a two-piece chassis providing inlet chamber <NUM>(<NUM>) and blower chamber <NUM>(<NUM>), two inlet chimneys <NUM> (e.g., arranged perpendicular to the blower axis), two chimneys <NUM> between the inlet chamber and the blower chamber, foam <NUM> providing arcuate channels or bends to interconnect the chimneys <NUM>, <NUM> while reducing noise, a snap-on outlet cover <NUM>, and legs <NUM> to hold a PCBA. In this arrangement, the inlet chamber is provided by a separate casing component, which allows the chimneys to be molded on any surface of the inlet chamber, e.g., perpendicular to the blower axis. It should be appreciated that a separate casing component for the inlet chamber may be applicable to other PAP device examples, e.g., PAP device shown in <FIG> and <FIG>.

<FIG> shows an example of a casing <NUM> in which the split line between the base <NUM>(<NUM>) and the cover <NUM>(<NUM>) is provided along the inlet, i.e., not the outlet as in <FIG> and <FIG>. In an example, the cover <NUM>(<NUM>) may provide chimney(s) <NUM>, a filter cover, and closure for the base in a one-piece structure. As illustrated, relatively long chimney(s) <NUM> may be molded (e.g., with side cores) along with the cover.

<FIG> shows an example of a casing <NUM> in which the chimney <NUM> and filter interface <NUM> are provided as a separate component, e.g., which allows a relatively long chimney to be molded. As illustrated, the base <NUM>(<NUM>) includes the flow conduits <NUM> and the cover <NUM>(<NUM>) provides the inlet chamber and the outlet cover.

<FIG> show an example of a casing structured to accommodate PCBA, i.e., slot-in PCBA with no separate enclosure provided to the casing to enclose the PCBA. As illustrated, each casing includes an inlet chamber <NUM>(<NUM>), a blower chamber <NUM>(<NUM>), and a chamber <NUM>(<NUM>) to accommodate the PCBA.

<FIG> and <FIG> show another example of a PAP device <NUM> which is similar to the PAP device <NUM> shown in <FIG> and <FIG>. In this example, the casing <NUM> (including base or chassis <NUM>(<NUM>) and cover <NUM>(<NUM>)) provides two chambers, i.e., inlet chamber <NUM>(<NUM>) and blower chamber <NUM>(<NUM>). As described above, inlet conduit(s) or chimney(s) <NUM> (e.g., two <NUM> inlet chimneys) extend from the inlet into the inlet chamber, flow conduits <NUM> extend between the inlet chamber and the blower chamber, and foam <NUM> is only provided within the blower chamber adjacent the blower inlet. The casing is structured to support and enclose a PCBA <NUM>, e.g., base <NUM>(<NUM>) includes enclosure walls to enclose and otherwise support sides and an end of the PCBA and cover <NUM>(<NUM>) includes snap-fit tab to support an end of the PCBA and releasably secure the PCBA to the casing. Also, an overmold <NUM>(<NUM>) is provided to the base of the casing and includes feet <NUM>(<NUM>)-<NUM> and flow ports <NUM>(<NUM>)-<NUM>, e.g., for flow sensor. It should be appreciated that the shape and/or size of the device may vary to support different blower designs.

A filter cover <NUM> is provided to the inlet of the casing to cover an inlet filter supported adjacent the inlet. As shown in <FIG>, the filter cover <NUM> may include supports <NUM>-<NUM> to support the cover at the inlet of the casing. In an alternative example, as shown in <FIG>, the filter cover <NUM> may include one or more inlet openings <NUM>-<NUM> along its top wall. In yet another example, as shown in <FIG>, the casing may be structured to support a filter insert <NUM> adapted to be inserted into a slot adjacent the inlet/inlet chimney <NUM> of the casing. As illustrated, the filter insert <NUM> may include a filter portion <NUM>-<NUM> and a cap or finger-grip portion <NUM>-<NUM> adapted to support or retain the filter portion within the slot.

<FIG> shows an example in which inlet chimneys <NUM> also provide flow conduits into a single chamber provided by the casing <NUM>.

Certain examples relate to systems in which the blower is adapted to be worn on the patient's head, is built into or incorporated into the patient interface or mask, is wearable or carried by the patient, is portable, is reduced in size or combinations thereof. In such examples, the blower may include the two stage variant as described above and its miniature size is especially beneficial (small overall product size).

In an example, one or more components of the blower may include relatively thin walls, e.g., to enhance blower performance. For example, housing part walls, impeller blades of the impellers and/or stator vanes of the stationary components may include relatively thin walls or thin wall sections, while maintaining overall balance of the component. Also, thin vanes and impeller leading edges minimize pressure losses and provide small size (less bulky walls).

For example, as shown in <FIG>, each impeller blade <NUM> of the impeller <NUM>-<NUM> may include a blade thickness at its base (i.e., where the blade meets the shroud <NUM>) of about <NUM> and a blade thickness at its top (i.e., opposite end in the axial direction to the blade's base) of about <NUM>, i.e., blade tapers to a thinner thickness at its top, e.g., for molding purposes. <FIG> is another exemplary view showing thin and tapered blades of the impeller.

As shown in <FIG>, each stator vane <NUM>-<NUM> of the shield <NUM> of the stationary component may include a vane thickness at its base in the range of about <NUM> to <NUM> and a vane thickness at its top in the range of about <NUM> to <NUM>.

As shown in <FIG>, each stator vane <NUM>-<NUM> of the housing <NUM> of the stationary component may include a vane thickness at its base that varies from <NUM> at the tips to <NUM> at the center and a vane thickness at its top that varies from <NUM> at the tips to <NUM> at the center. <FIG> also illustrates thin and tapered vanes of the stationary component.

Exemplary reasons for varying vane thickness include: leading edge needs to be relatively thin to avoid losses as the air "splits" between entering the vane passage and recirculating; and/or keeping the vane passage expanding (or diffusing in order to obtain static regain), helps to allow the vane to become thicker towards the trailing edge, i.e., towards the outlet of the vane passage.

Exemplary steps to achieve relatively thin impeller blades/stator vanes (e.g., to provide good "fill" of the mold cavities that form the blades/vanes) include mold venting and high speed material injection. In mold venting, multi-section inserts may be provided to create vents on the blade side. Also, porous steel may be used as the material for blade/vane side insert. Porous steel may provide mat finish on parts because porous steel will not have as high a polish finish as traditional tool steel. Also, relatively thin impeller blades/stator vanes may be provided using specific materials, injection molding machines, machine settings, mold and material temperature, and/or material injection speeds.

Claim 1:
A positive airway pressure, PAP, device (<NUM>) for delivery of respiratory therapy to a patient, the PAP device comprising a casing (<NUM>) and a blower (<NUM>) provided within the casing, the blower comprising:
a blower housing (<NUM>, <NUM>) including an inlet (<NUM>) and an outlet (<NUM>);
a motor (<NUM>) to drive a rotatable shaft (<NUM>);
second (<NUM>-<NUM>) and third (<NUM>-<NUM>) impellers provided to the shaft (<NUM>), the second and third impellers each including a plurality of impeller blades; and
a first impeller (<NUM>-<NUM>) positioned upstream of the second impeller (<NUM>-<NUM>);
a second stationary component (<NUM>) provided to the blower housing (<NUM>, <NUM>) and including stator vanes (<NUM>-<NUM>, <NUM>-<NUM>) downstream of the second impeller (<NUM>-<NUM>);
a third stationary component (<NUM>-<NUM>) provided to the blower housing (<NUM>, <NUM>) and including stator vanes (<NUM>) downstream of the third impeller (<NUM>-<NUM>);
a first stationary component (<NUM>-<NUM>) provided to the blower housing (<NUM>, <NUM>) and including stator vanes (<NUM>) following the first impeller (<NUM>-<NUM>), the first stationary component (<NUM>-<NUM>) being positioned upstream of the second impeller (<NUM>-<NUM>), the third (<NUM>-<NUM>) and first (<NUM>-<NUM>) stationary components being similar to one another,
wherein a first set of stator vanes (<NUM>-<NUM>, <NUM>-<NUM>) of the second stationary component (<NUM>) is provided around the motor (<NUM>) and is configured and arranged to direct airflow along the motor (<NUM>), to de-swirl the airflow and decelerate air to increase pressure;
wherein each of the third (<NUM>-<NUM>) and first (<NUM>-<NUM>) stationary components includes:
a respective shield (<NUM>) providing a respective first set of stator vanes (<NUM>-<NUM>); and
a respective stationary component housing (<NUM>) providing a respective second set of stator vanes (<NUM>-<NUM>), the shield (<NUM>) assembled to the stationary component housing (<NUM>) to provide a respective full set of stator vanes (<NUM>) including both the respective first (<NUM>-<NUM>) and second (<NUM>-<NUM>) sets of stator vanes;
wherein vane passages (<NUM>) each structured to provide an expanding passage to increase pressure are defined between adjacent stator vanes of each full set of stator vanes (<NUM>).