Breathing support system and blower for a breathing support system

Abstract

A respiratory system includes a dual outlet blower. One of a first outlet and a second outlet of the blower provides a flow of gas to one of a pair of nasal outlets of a nasal interface, and the other of the first outlet and the second outlet provides a flow of gas to the other of the pair of nasal outlets of the nasal interface. In alternative embodiments, one of the first outlet and the second outlet provides a flow of gas to a nasal outlet of an oral-nasal interface, and the other of the first outlet and the second outlet provides a flow of gas to an oral outlet of the oral-nasal interface.

Description

[0001] This application is a divisional application of the invention patent application entitled "Respiratory support system and blower for a respiratory support system", international application number PCT / IB2017 / 052427, international filing date 27 April 2017, national application number 201780035083.X. TECHNICAL FIELD

[0002] The present disclosure relates to a respiratory support system comprising a blower for providing a flow of breathing gas to a patient or user, and to a blower for a respiratory support system. BACKGROUND

[0003] Blowers (gas supply units) are used to generate a flow of breathing gas to be provided to a patient or user in order to treat a respiratory health problem. For example, continuous positive airway pressure devices and / or systems for treating sleep apnoea comprise a blower for providing a flow of air at positive pressure to support the airway of a user. In many cases, the blower is used with a humidifier to provide a flow of humidified gas to the user. Respiratory systems can comprise an integrated gas supply device comprising a humidifier and a blower. An example of a prior art integrated gas supply device is described in international patent publication WO 2013 / 009193.

[0004] A schematic diagram of a modular respiratory system is provided in Figure 1. The system comprises a blower 2 in fluid communication with a humidifier 4 via a conduit. A further conduit 3 provides a flow of gas generated by the blower 2 and humidified by the humidifier to a user 1 via a patient interface 5. A further schematic diagram is provided in Figure 2, which represents an integrated blower and humidification unit 6 comprising a blower 2 and a humidifier 4 as a single integrated unit.

[0005] In the systems of Figures 1 and 2, the patient interface 5 can be a full-face mask that provides a flow of gas to the airways of the user via the user's mouth and nose, or can be an oral or nasal interface. A nasal interface can seal against the face of the user around the nose, or can engage the nares of the user in a sealed or non-sealed manner. For example, a nasal cannula can provide a pair of prongs to engage the nares of the user without forming an airtight seal. Alternatively, a nasal interface can comprise a pair of nasal pillows that sealingly engage the nares of the user.

[0006] In this specification, where a document, act or other item of information is referred to by a number or other designation, reference is made to the specification for the document, act or other item of information, which can be incorporated herein by reference. In this specification, where reference is made to a patent or other external document, that reference is made only to the specification of the patent or other external document, not to any amendment to that specification. SUMMARY

[0007] It is an object of the present invention to provide an improved blower or respiratory support system, or at least to provide the industry or the public with a useful choice.

[0008] According to at least one of the embodiments disclosed herein, a blower for providing a flow or respiratory gas comprises a respiratory (support) system, the system comprising a dual outlet blower, wherein one of a first outlet and a second outlet of the blower provides a flow of gas to one of a pair of nasal outlets of a nasal interface, and the other of the first outlet and the second outlet provides a flow of gas to the other of the pair of nasal outlets of the nasal interface, or wherein one of the first outlet and the second outlet provides a flow of gas to a nasal outlet of an oronasal interface, and the other of the first outlet and the second outlet provides a flow of gas to an oral outlet of the oronasal interface.

[0009] In some embodiments, the blower comprises:

[0010] an impeller, and

[0011] a housing comprising an impeller chamber in which the impeller rotates, and a first outlet and a second outlet, the first outlet being arranged to direct a flow of gas from the housing when the impeller rotates in a first rotational direction, and the second outlet being arranged to direct a flow of gas from the housing when the impeller rotates in an opposite second rotational direction.

[0012] In some embodiments, the flow of gas from the first outlet is greater than the flow of gas from the second outlet in the case of rotation of the impeller in the first rotational direction, and

[0013] the flow of gas from the second outlet is greater than the flow of gas from the first outlet in the case of rotation of the impeller in the second rotational direction.

[0014] In some embodiments, rotation of the impeller in the first rotational direction produces a first flow of gas from the first outlet and a second flow of gas from the second outlet, and

[0015] rotation of the impeller in the opposite second rotational direction produces a first flow of gas or a third flow of gas from the second outlet and a second flow of gas or a fourth flow of gas from the first outlet, and

[0016] the first flow of gas has a flow rate greater than the flow rate of the second flow of gas, and the third flow of gas has a flow rate greater than the flow rate of the fourth flow of gas.

[0017] In some embodiments, the flow rate of the first flow of gas is substantially the same as the flow rate of the third flow of gas.

[0018] In some embodiments, the blower includes a motor for driving rotation of the impeller, and the housing includes an impeller chamber and a motor chamber for supporting the motor within the housing.

[0019] In some embodiments, the blower includes a first impeller and a second impeller, and the housing includes a first impeller chamber in which the first impeller rotates and a second impeller chamber in which the second impeller rotates, and

[0020] wherein the first impeller and the second impeller are rotationally coupled to rotate together, the first impeller is for producing a gas flow from the first outlet when the first impeller and the second impeller rotate in the first rotational direction, and the second impeller is for producing a gas flow from the second outlet when the first impeller and the second impeller rotate in the second rotational direction.

[0021] In some embodiments, the blower includes a motor for driving rotation of the first impeller and the second impeller, the motor including a rotor and a stator, wherein the first impeller and the second impeller are rotationally coupled to the rotor.

[0022] In some embodiments, the rotor is axially positioned between the first impeller and the second impeller, and

[0023] wherein the housing includes a motor chamber for the motor, the motor chamber being axially positioned between the first impeller chamber and the second impeller chamber.

[0024] In some embodiments, the impeller is a centrifugal impeller.

[0025] In some embodiments, the housing includes a volute chamber, the volute chamber receiving the gas flow from the impeller chamber.

[0026] In some embodiments, the first outlet extends substantially tangentially from the housing relative to a first rotational direction of the impeller, and the second outlet extends substantially tangentially from the housing relative to an opposite second rotational direction of the impeller.

[0027] In some embodiments, the volute chamber receives the gas flow from the first impeller chamber and the second impeller chamber.

[0028] In some embodiments, the housing includes:

[0029] a first volute chamber for receiving a gas flow from the first impeller chamber, the first outlet being arranged to direct a first gas flow from the first volute chamber, and

[0030] a second volute chamber for receiving a gas flow from the second impeller chamber, the second outlet being arranged to direct a second gas flow from the second volute chamber.

[0031] In some embodiments, the first outlet and the second outlet are axial outlets.

[0032] In some embodiments, the first outlet is an axial outlet on a first side of the blower and the second outlet is an axial outlet on a second side of the blower.

[0033] In some embodiments, the housing comprises a first stator ring and a second stator ring, each stator ring comprising a plurality of volute paths, the first axial outlet comprising a volute path of the first stator ring and the second axial outlet comprising a volute path of the second stator ring.

[0034] In some embodiments, each stator ring comprises a plurality of curved vanes, each said volute path being separated from an adjacent volute path in the stator ring by one said curved vane.

[0035] In some embodiments, each stator ring comprises a plurality of curved vanes, said curved vanes being spaced apart circumferentially radially outward of or adjacent or at a radially outer periphery of the impeller or a corresponding one of the first and second impellers.

[0036] In some embodiments, the blower comprises:

[0037] an impeller, and

[0038] a housing comprising an impeller chamber in which the impeller rotates and the first outlet and the second outlet, wherein:

[0039] rotation of the impeller in a first rotational direction produces a first gas flow from the first outlet and a second gas flow from the second outlet, and

[0040] rotation of the impeller in a second, opposite, rotational direction produces a first gas flow or a third gas flow from the second outlet and a second gas flow or a fourth gas flow from the first outlet, and

[0041] the first gas flow has a greater flow rate than the second gas flow and the third gas flow has a greater flow rate than the fourth gas flow.

[0042] In some embodiments, the blower comprises:

[0043] an impeller, and

[0044] An impeller housing comprising the first outlet and the second outlet, the first outlet extending substantially tangentially from the housing relative to a first rotational direction of the impeller, and the second outlet extending substantially tangentially from the housing relative to a second, opposite, rotational direction of the impeller.

[0045] In some embodiments, the system comprises a nasal interface, the interface comprising: a first nasal outlet for providing a flow of breathing gas to the user via one of the user's nostrils; and a second nasal outlet for providing a flow of breathing gas to the user via the other of the user's nostrils, wherein the first outlet of the blower is in fluid communication with the first nasal outlet of the nasal interface, and the second outlet of the blower is in fluid communication with the second nasal outlet of the nasal interface,

[0046] wherein rotation of the impeller of the blower in a first rotational direction generates a flow of gas to the first nasal outlet of the nasal interface, and rotation of the impeller in a second rotational direction generates a flow of gas to the second nasal outlet of the nasal interface.

[0047] In some embodiments, the system comprises: a sensing arrangement for determining occlusion of one of the user's nostrils; and a controller for controlling the direction of rotation of the impeller in response,

[0048] wherein if the sensing arrangement detects that one of the user's nostrils is at least partially occluded, the sensing arrangement causes the impeller to rotate in one of the first and second rotational directions to generate a flow to the other of the user's nostrils, and vice versa.

[0049] In some embodiments, the sensing arrangement comprises a pressure or flow sensor for detecting pressure or flow into or at the user's nostrils to determine whether one or other of the user's nostrils is at least partially occluded.

[0050] In some embodiments, the sensing arrangement comprises:

[0051] a first pressure or flow sensor for detecting pressure or flow into or at one of the user's nostrils to determine whether that one of the user's nostrils is at least partially occluded, and

[0052] a second pressure or flow sensor for detecting pressure or flow into or at the other of the user's nostrils to determine whether that other of the user's nostrils is at least partially occluded.

[0053] In some embodiments, the system includes an oronasal interface including a nasal outlet to provide a flow of breathing gas to the user via at least one of the user's nostrils and a mouth outlet to provide a flow of breathing gas to the user via the user's mouth, and

[0054] wherein the first outlet of the blower housing is in fluid communication with the nasal outlet of the oronasal interface and the second outlet of the blower housing is in fluid communication with the mouth outlet of the oronasal interface,

[0055] wherein rotation of the impeller in a first rotational direction produces a flow of gas to the nasal outlet and rotation of the impeller in a second rotational direction produces a flow of gas to the mouth outlet.

[0056] In some embodiments, the system includes a controller configured to control the rotational direction of the impeller based on at least one of a user input, a measured condition, or a predetermined condition.

[0057] According to at least one of the embodiments disclosed herein, a dual axial outlet blower includes:

[0058] an impeller, and

[0059] a housing including an impeller chamber in which the impeller rotates and a first axial outlet and a second axial outlet,

[0060] wherein, with the impeller rotating in a first rotational direction, a flow of gas from the first outlet is greater than a flow of gas from the second outlet, and

[0061] with the impeller rotating in a second rotational direction, a flow of gas from the second outlet is greater than a flow of gas from the first outlet.

[0062] In some embodiments, rotation of the impeller in a first rotational direction produces a first flow of gas from the first outlet and a second flow of gas from the second outlet, and

[0063] rotation of the impeller in an opposite second rotational direction produces a first flow of gas from the second outlet and a second flow of gas from the first outlet, and

[0064] the first flow of gas has a greater flow rate than the second flow of gas.

[0065] In some embodiments, the blower includes a motor to drive rotation of the impeller and the housing includes an impeller chamber and a motor chamber to support the motor within the housing.

[0066] In some embodiments, the impeller is a centrifugal impeller.

[0067] In some embodiments, the first outlet is an axial outlet on a first side of the blower and the second outlet is an axial outlet on a second side of the blower.

[0068] In some embodiments, the blower includes a first impeller and a second impeller, and the housing includes a first impeller chamber in which the first impeller rotates and a second impeller chamber in which the second impeller rotates, and

[0069] wherein the first impeller and the second impeller are rotationally coupled to rotate together, the first impeller generates a gas flow from the first outlet when the first impeller and the second impeller rotate in the first rotational direction, and the second impeller generates a gas flow from the second outlet when the first impeller and the second impeller rotate in the second rotational direction.

[0070] In some embodiments, the blower includes a motor for driving rotation of the first impeller and the second impeller, the motor including a rotor and a stator, wherein the first impeller and the second impeller are rotationally coupled to the rotor.

[0071] In some embodiments, the rotor is axially positioned between the first impeller and the second impeller, and

[0072] wherein the housing includes a motor chamber for the motor, the motor chamber being axially positioned between the first impeller chamber and the second impeller chamber.

[0073] In some embodiments, the housing includes a first stator ring and a second stator ring, each stator ring including a plurality of spiral paths, the first axial outlet includes a spiral path of the first stator ring, and the second axial outlet includes a spiral path of the second stator ring.

[0074] In some embodiments, the blower does not have spiral chambers other than the spiral paths of the stator rings.

[0075] In some embodiments, each stator ring includes a plurality of curved vanes, each of the spiral paths being separated from an adjacent spiral path in the stator ring by one of the curved vanes.

[0076] In some embodiments, each stator ring includes a plurality of curved vanes, the curved vanes being spaced apart circumferentially radially outward of or adjacent or at a radially outer periphery of the impeller or a corresponding one of the first impeller and the second impeller.

[0077] According to at least one of the embodiments disclosed herein, a dual axial outlet blower includes:

[0078] an impeller, and

[0079] a housing comprising:

[0080] an impeller chamber in which an impeller rotates, and

[0081] a first axial outlet and a second axial outlet, the first outlet arranged to direct a flow of gas from the housing when the impeller is rotating in a first rotational direction, and the second outlet arranged to direct a flow of gas from the housing when the impeller is rotating in a second, opposite, rotational direction.

[0082] In some embodiments, the impeller is a centrifugal impeller.

[0083] In some embodiments, the first outlet is an axial outlet on a first side of the blower, and the second outlet is an axial outlet on a second side of the blower.

[0084] In some embodiments, the blower comprises a first impeller and a second impeller, and the housing comprises a first impeller chamber in which the first impeller rotates and a second impeller chamber in which the second impeller rotates, and

[0085] wherein the first impeller and the second impeller are rotationally coupled so as to rotate together, the first impeller producing a flow of gas from the first outlet when the first impeller and the second impeller are rotating in the first rotational direction, and the second impeller producing a flow of gas from the second outlet when the first impeller and the second impeller are rotating in the second rotational direction.

[0086] In some embodiments, the housing comprises a first stator ring and a second stator ring, each stator ring comprising a plurality of spiral paths, the first axial outlet comprising a spiral path of the first stator ring, and the second axial outlet comprising a spiral path of the second stator ring.

[0087] In some embodiments, the blower has no spiral chambers other than the spiral paths of the stator rings.

[0088] In some embodiments, each stator ring comprises a plurality of curved vanes, each of the spiral paths being separated from an adjacent spiral path in the stator ring by one of the curved vanes.

[0089] In some embodiments, each stator ring comprises a plurality of curved vanes, the curved vanes being spaced circumferentially radially outward of or adjacent or at a radially outer periphery of the impeller or a corresponding one of the first and second impellers.

[0090] As used in the specification and claims, the term "comprising" means "at least partially comprising." Each of the expressions comprising, comprised of and comprising of as used in this specification and in the claims are to be interpreted identically. The term "comprising" as used in the claims does not exclude other elements or steps. The term "comprising" as used in the specification and claims does not exclude any possibility that "comprising" also means "consisting of" or "consisting essentially of."

[0091] A reference to a numerical range, e.g., 1 to 10, as disclosed herein, is intended to incorporate a recitation of all rational numbers within the stated range, e.g., 1, 1.1, 2, 3, 3.9, 4, 5, 6, 6.5, 7, 8, 9, and 10, as well as a recitation of any rational number range within the stated range, e.g., 2 to 8, 1.5 to 5.5, and 3.1 to 4.7, and thus all subranges of all ranges explicitly disclosed herein are expressly incorporated. These are merely specific examples on a particular range and all possible combinations of numerical values between the lowest value and the highest value are to be considered to be clearly stated in a similar manner in the present application.

[0092] As used herein, the term "and / or" means "and" or "or" or both.

[0093] As used herein, the term "(s)" following a noun means the plural and / or singular form of the noun.

[0094] Many modifications in the structure of this application, as well as many changes in the details of the preferred embodiments thereof, can be made by those ordinarily skilled in the art without departing from the scope of the application as defined by the appended claims. The disclosures and descriptions herein are purely illustrative and are not intended to be limiting in any sense.

[0095] The application consists in the foregoing and also envisages various structural modifications, only examples of which are given below. BRIEF DESCRIPTION OF DRAWINGS

[0096] The preferred embodiments of the present application will be illustrated by way of example only and with reference to the accompanying drawings, in which:

[0097] Fig. 1 is a schematic illustration of a prior art breathing system.

[0098] Fig. 2 is a schematic illustration of another prior art breathing system.

[0099] FIG. 3 is a schematic illustration of a breathing system according to at least one of the embodiments disclosed herein.

[0100] FIG. 4A blower housing for a blower is shown according to at least one of the embodiments disclosed herein.

[0101] FIG. 5A and FIG. 5B This is an exploded view of a blower according to at least one of the embodiments disclosed herein, which includes FIG. 4 The housing is shown, but the motor is omitted from the diagram.

[0102] FIG. 6 It shows FIG. 5A and FIG. 5B A blower, in which a portion of the casing has been removed to show an end view of the blower's impeller.

[0103] FIG. 7 It shows in FIG. 6 Obtained on line IIX-IIX in FIG. 5A and FIG. 5B The cross-section of the blower.

[0104] FIG. 8 It shows FIG. 4 A cross-sectional view of the blower housing, showing the vortex chamber and motor chamber of the housing.

[0105] FIG. 9 An alternative blower housing for a blower is shown according to at least one of the embodiments disclosed herein.

[0106] FIG. 10 A cross-section of a blower according to at least one of the embodiments disclosed herein is shown, comprising: FIG. 9 The shell, the cross section is FIG. 9 It was obtained from line XX in the middle.

[0107] FIG. 11 It shows the applicability FIG. 10 The cross-section of the motor configuration of the blower.

[0108] FIG. 12 It shows what can be used for FIG. 3 A typical cross-section of a respiratory intubation tube.

[0109] FIG. 13 An axial outlet blower according to at least one of the embodiments disclosed herein is shown.

[0110] FIG. 14 and FIG. 15 The diagram shows the blower from one side and at each end. FIG. 13 An exploded view of the blower.

[0111] FIG. 16 It shows FIG. 13 A cross-sectional view of the blower, wherein the cross-section is inFIG. 13 A cross-section view of the blower of FIG. 1 is shown, with the cross-section taken on the line XVI-XVI shown, the cross-section being in a plane adjacent the outer diameter of the impeller of the blower, to show the spiral path providing the first and second axial outlets of the blower.

[0112] FIG. 17 A cross-section view of the blower of FIG. 1 is shown, with the cross-section taken on the line XVI-XVI shown, the cross-section being in a plane adjacent the outer diameter of the impeller of the blower, to show the spiral path providing the first and second axial outlets of the blower. FIG. 13 A cross-section view of the blower of FIG. 1 is shown, with the cross-section taken on the line XVI-XVI shown, the cross-section being in a plane adjacent the outer diameter of the impeller of the blower, to show the spiral path providing the first and second axial outlets of the blower.

[0113] FIG. 18 A cross-section view of the blower of FIG. 1 is shown, with the cross-section taken on the line XVI-XVI shown, the cross-section being in a plane adjacent the outer diameter of the impeller of the blower, to show the spiral path providing the first and second axial outlets of the blower. FIG. 13 An impeller of the blower of FIG. 1 is shown.

[0114] FIG. 19 An alternate bearing support configuration for the blower shaft and impeller is shown.

[0115] FIG. 20 An axial outlet blower in accordance with at least one of the embodiments disclosed herein is shown.

[0116] FIG. 21 A cross-section view of the blower of FIG. 1 is shown, with the cross-section taken on the line XVI-XVI shown, the cross-section being in a plane adjacent the outer diameter of the impeller of the blower, to show the spiral path providing the first and second axial outlets of the blower. FIG. 20 A cross-section view of the blower of FIG. 1 is shown, with the cross-section taken on the line XVI-XVI shown, the cross-section being in a plane adjacent the outer diameter of the impeller of the blower, to show the spiral path providing the first and second axial outlets of the blower. FIG. 20 A cross-section view of the blower of FIG. 1 is shown, with the cross-section taken on the line XVI-XVI shown, the cross-section being in a plane adjacent the outer diameter of the impeller of the blower, to show the spiral path providing the first and second axial outlets of the blower.

[0117] FIG. 22 A cross-section view of the blower of FIG. 1 is shown, with the cross-section taken on the line XVI-XVI shown, the cross-section being in a plane adjacent the outer diameter of the impeller of the blower, to show the spiral path providing the first and second axial outlets of the blower. FIG. 20 A cross-section view of the blower of FIG. 1 is shown, with the cross-section taken on the line XVI-XVI shown, the cross-section being in a plane adjacent the outer diameter of the impeller of the blower, to show the spiral path providing the first and second axial outlets of the blower.

[0118] FIG. 23 An impeller of the blower of FIG. 1 is shown, as seen from one side and each end of the impeller. FIG. 20 An impeller of the blower of FIG. 1 is shown, as seen from one side and each end of the impeller.

[0119] FIG. 24 A dual impeller and rotor assembly of the blower of FIG. 1 is shown. FIG. 20 A dual impeller and rotor assembly of the blower of FIG. 1 is shown. DETAILED DESCRIPTION

[0120] Various embodiments are described with reference to the accompanying drawings. Like reference numerals are used throughout the description and drawings to indicate the same or similar components.

[0121] The present disclosure relates to an improved blower or respiratory system for providing a flow of breathing gas to a user. In some embodiments, the gas is provided to the user via a nasal interface that engages the user's nostrils. The nasal interface can be a non-sealing or a sealing interface. In some embodiments, the nasal interface can be a nasal cannula, or alternatively a nasal interface with a nasal pillow that seals against a respective nostril of the user. In each example, the nasal interface includes two outlets, each for providing a flow of gas to a respective one of the user's two nostrils. FIG. 12 An example nasal interface is shown that includes two outlets.

[0122] One of the user's or patient's nostrils receiving the flow of breathing gas from the blower can be occluded or partially occluded, for example because mucus has accumulated within one of the user's nasal passages. In the event of an occlusion or partial occlusion in one of the patient's nostrils, the respiratory gas therapy provided by the respiratory system can not be as effective as if both of the user's nostrils were not so occluded or partially occluded. Alternatively, in some cases, the user can prefer to breathe via the mouth, and in such cases it can be beneficial to flush the user's nasal passages with air or to provide a flow of gas between the user's nostrils and the mouth (e.g. periodically).

[0123] Reference FIG. 3 The system according to some embodiments includes a dual outlet blower 10, where each outlet 11, 12 provides a flow of gas to one of a pair of nasal outlets 21, 22 of a nasal interface 5, according to the schematic diagram of Figure 1.

[0124] According to embodiments described herein, the dual outlet blower 10 includes an impeller 15 and a housing that includes a first outlet 11 and a second outlet 12. The first outlet 11 is arranged to direct a flow of gas from the housing when the impeller is rotating in a first rotational direction, and the second outlet 12 is arranged to direct a flow of gas from the housing when the impeller is rotating in an opposite second rotational direction. The dual outlet blower 10 provides a way to direct the flow of gas to one or the other of the user's nostrils by simply selecting the rotational direction of the blower impeller. In the event of an occlusion or partial occlusion in one of the user's nostrils, the flow can be provided to the other of the user's nostrils by selecting the corresponding rotational direction of the impeller.

[0125] The rotation of the impeller is driven by a motor 25. The motor is adapted to rotate the impeller in both the first rotational direction and the opposite second rotational direction. Energising the motor to rotate the impeller in the first rotational direction produces a flow of gas from the first outlet of the housing. This flow can be directed to the first nasal outlet of the nasal interface. Energising the motor to rotate the impeller in the opposite second rotational direction produces a flow of gas from the second outlet of the housing. This flow can be directed to the second nasal outlet of the nasal interface.

[0126] The system according to embodiments herein comprises a first breathing system between the first blower outlet 11 and the first outlet 21 of the nasal interface 5, and a second breathing system between the second blower outlet 12 and the second outlet 22 of the nasal interface 5, wherein the first and second breathing systems are pneumatically separated. The first and second breathing systems can each comprise a conduit 3a, 3b extending between the corresponding blower outlet 11, 12 and the corresponding nasal interface outlet 21, 22. In some embodiments, the nasal interface comprises a first inlet 51 in pneumatic communication with the first outlet 21 of the nasal interface via a first lumen, and a second inlet 52 in pneumatic communication with the second outlet 22 of the nasal interface via a second lumen, wherein the first and second lumens are pneumatically separated. The first conduit 3a can extend between the first outlet 11 of the blower and the first inlet 51 of the nasal interface, and the second conduit 3b can extend between the second outlet 12 of the blower and the second inlet 52 of the nasal interface.

[0127] In some embodiments, the system can comprise dual humidification. For example, the first breathing system between the first blower outlet 12 and the first outlet 21 of the nasal interface can comprise a first humidifier 4a, and the second breathing system between the second blower outlet 12 and the second outlet 22 of the nasal interface can comprise a second humidifier 4b, as shown in the schematic illustration of FIG. 3 Alternatively, the system can be without humidification, to provide a flow of unhumidified gas to the user. In another alternative embodiment, a single humidifier can be provided upstream of the blower, to humidify the flow of gas entering the blower via the blower inlet 13.

[0128] In some embodiments, the breathing system comprises a sensing arrangement to determine occlusion or partial occlusion of one of the user’s nostrils, and to control the direction of rotation of the impeller in response. If the sensing arrangement detects that one of the user’s nostrils is at least partially occluded, the sensing arrangement can cause the impeller to rotate in one of the first and second directions of rotation to generate a flow to the other of the user’s nostrils, and vice versa.

[0129] In some embodiments, the sensing arrangement can comprise pressure or flow sensors to detect pressure or flow into or at the user's nares in order to determine whether one or other of the user's nares is at least partially occluded. For example, the sensing arrangement can comprise a first pressure or flow sensor 61 to detect pressure or flow into or at one of the user's nares in order to determine whether this naris of the user is at least partially occluded, and a second pressure or flow sensor 62 to detect pressure or flow into or at the other of the user's nares in order to determine whether this other naris of the user is at least partially occluded. The controller 40 can be provided to receive signals from the sensing arrangement to energise the motor 25 to rotate the impeller in the first direction or the second direction depending on whether one or other of the user's nasal passages is occluded or partially occluded. For example, the pressure or flow sensors can provide signals to the controller which compares the signals to a threshold, and in the event that the signals indicate that the pressure or flow at one of the user's nares is greater or less than a predetermined threshold indicative of one naris being at least partially occluded, the controller can energise the motor to rotate the impeller in one of the first and second rotational directions to cause the flow of gas to be provided to the non-occluded one of the user's nares. In FIG. 3 In the middle, the sensors 61, 62 are indicated as being located at the patient interface, however the sensors can be located elsewhere in the system, for example at the outlet 11, 12 of the blower or between the outlet of the blower and the outlet of the nasal interface.

[0130] In some embodiments, a respiratory system includes a dual outlet blower 10 in which one of the first outlet 11 and the second outlet 12 provides a flow of gas to at least one of the user's nares and the other of the first outlet 11 and the second outlet 12 provides a flow of gas to the user's mouth. In some embodiments, the respiratory support system includes a mouth-nose interface. The mouth-nose interface includes at least one nasal outlet for providing a flow of breathing gas to the user via at least one of the user's nares and a mouth outlet for providing a flow of breathing gas to the user via the user's mouth. The first outlet of the blower housing is in fluid communication with the nasal outlet of the mouth-nose interface and the second outlet of the blower housing is in fluid communication with the mouth outlet of the mouth-nose interface. Rotation of the impeller in a first rotational direction produces a flow of gas to the nasal outlet and rotation of the impeller in a second rotational direction produces a flow of gas to the mouth outlet. The system can include a controller configured to control the rotational direction of the impeller based on at least one of a user input, a measured condition, or a predetermined condition. For example, the controller can control the impeller to rotate in one direction to provide a flow to the user's mouth and to periodically rotate in the opposite direction to provide a flow to the user's nares in order to periodically flush the user's nasal passage.

[0131] It is also possible to provide a system that includes a first blower and a separate second blower. In one configuration, the first blower can provide a flow of gas to one of a pair of nasal outlets of a nasal interface and the second blower can provide a flow of gas to the other of the pair of nasal outlets of the nasal interface. In another configuration, the first blower can provide a flow of gas to one of a nasal outlet and a mouth outlet of a mouth-nose interface and the second blower can provide a flow of gas to the other of the nasal outlet and the mouth outlet of the mouth-nose interface.

[0132] Reference is now made to FIG. 4 to FIG. 8 Examples of dual outlet blowers suitable for implementation in systems such as those described above are described. Other alternatives are also described, including reference to FIG. 9 to FIG. 11 The blower described.

[0133] FIG. 4 A housing 70 of the blower 10 is shown. Figures 5a and 5b show exploded views of the blower 10, but with the motor of the blower omitted. A motor that can be suitable for driving the impeller is described in International Patent Publication WO 2013 / 009193, the contents of which are incorporated herein by reference.

[0134] As shown, the blower 10 includes an impeller 15 and a housing 70. The housing includes an impeller chamber 20 FIG. 7), impeller rotates in the impeller chamber to produce a pressurized gas flow, and first and second outlets 11 and 12. The first outlet 11 is arranged to direct a flow of gas from the housing 70 when the impeller is rotated in a first direction of rotation (shown as direction A in FIG. 6 FIG. 6

[0135] As shown in Figures 5a and 5b, in some embodiments the housing can comprise two or more pieces that are assembled together. In the illustrated embodiment, the housing comprises a first or main housing portion 71 and a second housing portion or cover 72 that is assembled to the first housing portion 71. The first housing portion 71 can comprise the first and second outlets, and the second housing portion or cover 72 can comprise the blower inlet 13.

[0136] The first and second inlets 11 and 12 each comprise a conduit that extends from the volute chamber 30 of the housing 70. Generally, a "volute chamber" in a pump is a curved funnel whose area increases toward the outlet of the pump. However, in this specification and claims, the term "volute chamber" should be interpreted broadly to mean a housing or chamber that receives air pumped by the impeller from the impeller chamber and in which the velocity of the air flow is reduced to produce a relatively higher pressure. Thus, the volute chamber of a blower according to the embodiments described herein is not necessarily volute-shaped.

[0137] Rotation of the impeller within the impeller chamber draws air into the impeller chamber 30 via the inlet 13 of the blower. The inlet 13 is preferably centrally located relative to the rotational axis of the impeller.

[0138] As the impeller rotates in the impeller chamber, the impeller draws air from the inlet into the impeller chamber, and then forces the air from the impeller chamber into the volute chamber via the passage 19 between the impeller chamber 20 and the volute chamber 30. The air collected in the volute chamber passes from the volute chamber via either the first outlet 11 or the second outlet 12, depending on the direction of rotation of the impeller.

[0139] In the figures, the impeller is shown as an asymmetric impeller, which is an impeller that is configured to produce more flow when rotated in one direction than when rotated in the opposite direction. For example, in an asymmetric impeller, the impeller blades 16 can be angled from the hub 17 of the impeller and / or can be curved or otherwise shaped to cause the impeller to preferentially rotate in one direction. However, in other embodiments, the impeller can be a symmetric impeller, e.g., configured with radially extending blades that are flat or otherwise shaped to produce a given flow for a given rotational speed, regardless of the direction of rotation.

[0140] ​​In some embodiments, the impeller chamber 20 and the volute chamber 30 are separated by a partition wall. In some embodiments, the impeller chamber is separated from the volute chamber by a partition wall 35 of the housing 70. In some embodiments, the passage 19 between the impeller chamber 20 and the volute chamber 30 is an aperture in the partition wall. As shown, in some embodiments, the partition wall does not extend completely to the side wall 36 of the volute chamber, and the passage is a gap 19 between the edge 37 of the partition wall 35 and the side wall 36. The side wall can be a circumferential side wall of the housing of the blower. In some embodiments, the passage 19 is crescent shaped. In some embodiments, the gap 19 between the partition wall and the side wall is crescent shaped. For example, as shown in FIG. 1, the partition wall 35 is a circumferential wall of the housing 70, and the gap 19 is a crescent shaped gap between the edge 37 of the circumferential wall 35 and the circumferential side wall 36 of the housing 70. In some embodiments, the gap 19 is crescent shaped, tapering from one or more narrow points 19n on either side of a widest point 19w of the passage to the widest point on either side. Preferably, the widest point 19w is located midway between the first outlet 11 and the second outlet 12, as shown in FIG. 1. In some embodiments, the gap 19 is crescent shaped, tapering from one or more narrow points 19n on either side of a widest point 19w of the passage to the widest point on either side. Preferably, the widest point 19w is located midway between the first outlet 11 and the second outlet 12, as shown in FIG. 1. FIG. 6 Preferably, the widest point 19w is located midway between the first outlet 11 and the second outlet 12, as shown in FIG. 1. In some embodiments, the gap 19 is crescent shaped, tapering from one or more narrow points 19n on either side of a widest point 19w of the passage to the widest point on either side. Preferably, the widest point 19w is located midway between the first outlet 11 and the second outlet 12, as shown in FIG. 1. FIG. 6 Preferably, the widest point 19w is located midway between the first outlet 11 and the second outlet 12, as shown in FIG. 1. In some embodiments, the gap 19 is crescent shaped, tapering from one or more narrow points 19n on either side of a widest point 19w of the passage to the widest point on either side. Preferably, the widest point 19w is located midway between the first outlet 11 and the second outlet 12, as shown in FIG. 1.

[0141] In some embodiments, the first outlet 11 and the second outlet 12 extend tangentially or substantially tangentially from the volute chamber. For example, the outlets can extend from the housing at an angle of less than 30 degrees, or less than 20 degrees, or less than 10 degrees, to a tangent to the axis of rotation of the impeller. In some embodiments, the first outlet 11 extends substantially tangentially from the housing with respect to a first direction of rotation of the impeller, and the second outlet 12 extends substantially tangentially from the housing with respect to a second, opposite direction of rotation of the impeller. For example, as shown in FIG. 1, the first outlet and the second outlet are positioned to mirror each other with respect to a centre line of the housing or a line extending through the axis of rotation of the impeller, such that the outlets are parallel and both extend in a single lateral direction. Other arrangements are possible, for example the first outlet 11 and the second outlet 12 can extend at right angles or 90 degrees to each other from the housing. In yet another alternative, the outlets can be in line and extend in opposite lateral directions. For example, with reference to FIG. 2. FIG. 6 Preferably, the widest point 19w is located midway between the first outlet 11 and the second outlet 12, as shown in FIG. 1. In some embodiments, the gap 19 is crescent shaped, tapering from one or more narrow points 19n on either side of a widest point 19w of the passage to the widest point on either side. Preferably, the widest point 19w is located midway between the first outlet 11 and the second outlet 12, as shown in FIG. 1. FIG. 6wherein the first outlet 11 and the second outlet 12 extend downward, in some embodiments the first outlet 11 can extend downward and the second outlet 12 can extend upward and be in line with the first outlet. As shown, the impeller is a centrifugal impeller. A centrifugal impeller produces a flow velocity that can be decomposed into a tangential velocity component and a radial velocity component. In some embodiments, the first outlet is arranged to extend from the housing to receive at least a substantial portion of the tangential velocity component of the air flow produced by the impeller when rotated in the first rotational direction, and the second outlet is arranged to extend from the housing to receive at least a substantial portion of the tangential velocity component of the air flow produced by the impeller when rotated in the second rotational direction. Thus, by simply changing the rotational direction of the impeller by changing the motor rotational direction, the air flow can be directed primarily from the first outlet or the second outlet of the housing. The blower arrangement is configured for motor direction control to provide flow to the selected outlet and thus to the selected one of the user’s nostrils or the selected one of the user’s nose and mouth without the need for other devices such as valves and valve actuation devices.

[0142] In some embodiments, rotation of the impeller in the first rotational direction produces a first gas flow from the first outlet and a second gas flow from the second outlet, wherein the first gas flow is greater than the second gas flow. In embodiments where the flow paths from the impeller to the first outlet and the second outlet are identical and the impeller is symmetrical, rotation of the impeller in the second, opposite rotational direction produces a first gas flow from the second outlet and a second gas flow from the first outlet. In other words, for a given impeller speed, a particular flow rate is provided via the first outlet in the first rotational direction and the same flow rate is provided by the second outlet in the second rotational direction. Alternatively, for example where the impeller is not symmetrical, rotation of the impeller in the first rotational direction produces a first gas flow from the first outlet and a second gas flow from the second outlet, and rotation of the impeller in the second, opposite rotational direction produces a third gas flow from the second outlet and a fourth gas flow from the first outlet, wherein the flow rate of the first gas flow is greater than the flow rate of the second gas flow, and the flow rate of the third gas flow is greater than the flow rate of the fourth gas flow. For symmetrical blower configurations, the third flow rate is substantially equal to the first flow rate, and the fourth flow rate is substantially equal to the second flow rate.

[0143] In some embodiments, the housing 10 provides a motor chamber 60 for housing a motor within the blower housing. In some embodiments, the volute chamber 30 extends around the motor chamber 60. In other words, the motor is positioned radially inward of the annular volute chamber 30. In some embodiments, the motor is positioned radially inward of the annular volute chamber. An aperture is provided between the motor chamber and the impeller chamber such that a shaft of the motor or the impeller can extend between the impeller and the motor, thereby rotationally coupling the impeller to the motor. Positioning the motor radially inward of the annular volute chamber enables a flat (small axial length) blower configuration.

[0144] In some embodiments, the blower can include one or more electronic circuit boards, for example, the blower can include motor control electronics. In some embodiments, the electronics can be provided remotely from the blower. In such embodiments, a cable to the blower can provide communication from a remote motor controller to the motor as well as motor control current and / or voltage.

[0145] The flow performance data table for the blower shown in FIG. 4 Figure 1 is provided below. Blocked flow indicates the pressure generated at the outlet 11, 12 of the blower if the outlet is blocked. Bias resistance flow is the flow expelled from the patient interface (e.g. nasal prongs 5) in FIG. 3 Figure 1 when the outlet from the interface is blocked. For example, if the resistance expels about 30 to 40 lpm at 10 cm H20, there is a leak at the interface. Bias flow is the minimum leak in the breathing system, independent of the patient's inhalation and exhalation. Unblocked flow is the flow achieved at the outlet 11, 12 without downstream flow resistance.

[0146]

[0147] As shown in the table, for the unblocked flow with the impeller rotating in one direction, the flow from one outlet is about 20% of the flow from the other outlet. However, in practice there is no such significant difference in the flow from the two outlets experienced. For the bias flow, the flow from one outlet is about 80% of the flow from the other outlet. In normal operation, during exhalation, the blower provides a flow in the range between the blocked flow (zero flow) and the bias flow, and during inhalation, the peak flow (including bias flow) provided by the blower can be about 80 lpm at 10K rpm. Thus, in normal operation, during inhalation, the flow from one outlet can be about one third of the flow from the other outlet.

[0148] Reference is made to FIG. 9 to FIG. 11 an alternative blower 110 is described. FIG. 9 An alternative housing 170 is shown, and FIG. 10 a cross-section of a blower 110 with the motor omitted is shown in FIG. 9 The blower including the housing of Figure 1 includes two impellers 15a and 15b, as FIG. 10The two impellers are axially spaced apart. The housing 170 includes a first impeller chamber 20a for receiving the first impeller 15a and a second impeller chamber 20b for receiving the second impeller 15b. A first partition wall 35a separates the first impeller chamber 20a from the first volute chamber 30a. A second partition wall 35b separates the second impeller chamber 20b from the second volute chamber 30b. In some embodiments, the housing 170 can include a single volute chamber that receives gas flow from both the first and second impeller chambers. Each impeller chamber is in communication with the volute chamber or chambers via an aperture or gap 19a, 19b, as described with reference to the embodiments of FIG. 4 to FIG. 8 FIG. 9 and FIG. 10 The motor chamber and the motor are axially located between the first and second impeller chambers. The rotor is coupled to the first and second impellers 15a, 15b such that the rotor, and the first and second impellers, rotate together. In a first rotational direction, the first impeller generates a gas flow to exit the first volute chamber or volute chambers via the first outlet 11. In a second rotational direction, the second impeller generates a gas flow to exit the second volute chamber or volute chambers via the second outlet 12.

[0149] FIG. 11 An exemplary rotor and dual impeller configuration for the blower 110 is shown. The motor 25 includes a rotor 26 coupled to the first and second impellers 15a, 15b by a shaft 28. The rotor is positioned inside a stator 27 and is supported for rotation relative to the stator 27 by bearing elements 29. The bearing elements are supported by a bearing support 31. The bearing support can be resilient, for example formed of an elastomer. In the embodiment shown, the bearing elements are supported by the bearing support 31 between the stator and the bearing elements, with the bearing elements located on the shaft. The stator is supported in a motor chamber 60 of the blower housing 170. A resilient mount can be provided to mount the stator within the motor chamber 60. Similar motor and impeller arrangements can be used for the blower 10 described with reference to FIG. 4 to FIG. 8 but in which a single impeller is coupled to the shaft 27 extending from one end of the motor.

[0150] FIG. 4 to FIG. 8 and FIG. 9 and FIG. 10 ​The blowers shown in the figures are centrifugal blowers that include a centrifugal impeller(s) and a housing to produce a tangential air flow. However, in other embodiments, the dual outlet blowers can include one or more impellers and a housing to produce an axial air flow. In some embodiments, the blowers including an impeller include a first axial outlet at a first side of the blower and a second axial outlet at a second side of the blower. In a first rotational direction, the impeller produces a flow of gas that exits the housing at the first axial outlet. In a second rotational direction, the impeller produces a flow of gas that exits the housing at the second axial outlet. In some embodiments, the blower includes a housing having a first impeller chamber for receiving a first impeller and a second impeller chamber for receiving a second impeller, and a first axial outlet associated with the first impeller chamber and a second axial outlet associated with the second impeller chamber. The housing can also include a single motor chamber. A motor including a stator and a rotor is located in the motor chamber. The motor chamber and motor can be axially located between the first impeller chamber and the second impeller chamber. The axial flow blower can include a dual impeller and rotor configuration, like FIG. 12 the configuration shown, where the rotor is coupled to the first impeller and the second impeller such that the rotor rotates with the first impeller and the second impeller. In a first rotational direction, the first impeller produces a flow of gas that exits the housing at the first axial outlet. In a second rotational direction, the second impeller produces a flow of gas that exits the housing at the second axial outlet. The one or more impellers can be centrifugal impellers.

[0151] Reference is made to FIG. 13 to FIG. 19 An exemplary dual axial outlet blower is described. The blower 210 includes a housing 270. The housing can include a first housing portion 271 and a second housing portion 272. The housing includes a first wall 273 and a second wall 274 that are axially spaced apart by a circumferential wall 275. The first and second walls and the circumferential wall combine to form an impeller chamber 20 for receiving an impeller 215. The first and second walls are preferably planar and perpendicular to an axis of rotation of the impeller of the blower. In the embodiment shown, the first and second walls are annular.

[0152] The housing also includes a first central hub 276 and a second central hub 277. In some embodiments, the first central hub 276 is connected to an inner periphery of the first annular wall 273 via radial ribs 278. In some embodiments, the second central hub 277 is connected to an inner periphery of the second annular wall 274 via ribs 279. Preferably, the ribs connecting each hub to the respective annular wall extend radially between the hub and the annular wall.

[0153] In some embodiments, the radial ribs 278 extending between the first annular wall 273 and the first center hub 276 include an axially extending portion 278a and a radially extending portion 278b, such that the first center hub 276 is axially spaced apart from the first annular wall 273 and axially distanced from the impeller chamber 20. This forms a recessed area defined by the first center hub 276 and the ribs 278 extending between the first center hub and the first annular wall. The recessed area forms a motor chamber 60 for receiving the motor 225 including the stator 227 and the rotor 226. The first hub 276 acts as a support for the stator and as at least partial support for the first bearing 229, which in turn provides support for the rotor 226 and the impeller 215 assembly. The openings or gaps 213 between the ribs 278 provide the first axial inlet 213. This also provides motor cooling.

[0154] The second center hub 277 provides at least partial support for the second bearing, which in turn also provides support for the rotor 226 and the impeller 215 assembly. In some embodiments, the openings or gaps 214 between the ribs 279 provide the second axial inlet 214.

[0155] The motor 225 includes a stator 227 and a rotor 226. The stator is supported by the radial ribs 278 and is radially positioned by the axial portions 278a of the ribs and axially positioned by the radial portions 278b of the ribs. The stator 227 includes an annular stacked lamination core 227a with a ring-like winding 227b. The rotor includes an annular or ring-shaped magnet 226a coupled to a shaft 228. The lower end of the shaft has an annular notch 228a with an outer diameter comparable to the inner diameter of the annular magnet 226a for receiving the annular magnet. The shaft 228 can be a cylindrical tube in the form of a bearing tube. Bearings (e.g., 229) are provided at each end of the bearing tube. Each bearing can include an outer annular bearing race / housing, an inner annular bearing race / housing, and a ball or roller bearing movable therebetween. As one non-limiting example, the bearing can have an outer diameter of about 4 mm to 8 mm, an inner diameter of about 1.5 mm to 3 mm, and a thickness of about 2 mm to 4 mm.

[0156] The outer bearing race rotates relative to the inner bearing race. The inner bearing race can remain fixed. In the alternative, a plain bearing or bushing can be used instead. The shaft 228 is supported between the first and second center hubs. Both the first and second housing portions include stub shafts 269a, 269b that extend from the center hub in the form of compliant and / or elastic protrusions that extend into and couple with the respective bearings at each end of the shaft. The protrusions extend into and couple with the bearing races of the respective bearings. Preferably, the stub shafts are formed of an elastomer (e.g., silicone) or other compliant and / or elastic material and are friction fit within the respective bearing races. Alternatively, the stub shafts can be solid and / or rigid and overmolded with an elastic and / or flexible material. Alternatively, the stub shafts can be solid. The stub shaft / bearing arrangement enables the shaft to be rotatably supported / coupled to the first and second hubs in a simple supported manner.

[0157] The outer bearing race can be, for example, about 4 mm in outer diameter. The hollow shaft can have a comparable diameter of about 4 mm to allow for a close fit of the bearing races. The outer shaft size in the slot 228a can be about 5 mm.

[0158] The impeller 215 can be coupled (e.g., press fit) to or formed integrally with the shaft 228. The shaft can have a similar diameter as the shafts in conventional topologies, which allows for a robust mechanical coupling of the impeller. Since the bearings fit on the inside of the shaft, the diameter of the shaft is not dictated by the bearing inner diameter. The outer diameter of the shaft can then be of a suitable size to allow for a robust impeller coupling, for example, about 5 mm, or between about 3 mm and about 5 mm. A larger diameter shaft (resulting in an undesirable high bearing speed) can still be used without dictating the bearing diameter size, since the bearings are on the inside of the shaft, so the size (e.g., diameter size) of the bearings can be selected based on acceptable bearing speeds.

[0159] Similarly, the magnets / rotors 226a / 226 are press fit into the shaft. Similar advantages apply here, where the shaft can be of a suitable size to allow for a robust coupling.

[0160] The impeller 215 includes a hub portion 217 and (full length) blades (sometimes referred to as “vanes”) 216 that extend radially from and are connected to the hub portion. In the illustrated embodiment, the blades extend radially from the hub, although other arrangements are possible, for example, the blades can be tilted forward relative to the direction of rotation of the impeller. The blades can be flat or straight, or the blades can be curved. An annular rib / ring 218 extends between the full length blades to provide rigidity to the blade periphery. The ring can taper in thickness toward the outer and inner radial edges, as shown in the illustrated embodiment, or the ring can be constant in thickness. The hub portion 217 can be formed of a single piece with the blades 216, or the hub portion 217 can be formed separately from the blades 216 and coupled thereto. The hub portion 217 can be formed of a single piece with the ring 218, or the hub portion 217 can be formed separately from the ring 218 and coupled thereto. The hub portion 217 can be formed of a single piece with the shaft 228, or the hub portion 217 can be formed separately from the shaft 228 and coupled thereto. The hub portion 217 can be formed of a single piece with the first and second housing portions 261, 262, or the hub portion 217 can be formed separately from the first and second housing portions 261, 262 and coupled thereto. The hub portion 217 can be formed of a single piece with the first and second center hubs 263, 264, or the hub portion 217 can be formed separately from the first and second center hubs 263, 264 and coupled thereto. FIG. 17The multiple short (partial length) blades 216b (also referred to as "splitter blades") that extend partially into the hub are spaced between the full length blades 216. Annular ribs 218 also extend between the short blades 216b, supporting them from the full length blades. The short blades provide additional pressure that would normally be achieved with additional blades, without the need for material extending to the hub, which would reduce the air space at the hub. Reducing the air space at the hub reduces the maximum flow capacity of the blower 210. If the number of blades is too many (and thus the air space at the hub is too small due to too many blades), then the inlet flow is choked, limiting the outlet air flow of the blower.

[0161] Material properties and construction technology requirements favor increasing the number of blades when pumping liquids, as liquids have a higher density. For example, multiply the rotational rate (Hz) by the number of blades to determine the blade pass frequency. Human hearing is sensitive to tone inputs between 300 Hz and 15 kHz, and is classified as noise if not pleasing to the ear. High frequency sound waves attenuate more easily than low frequency noise. Typical CPAP blowers rotate at about 180 revolutions per second. It is therefore advantageous to increase the number of blades to improve the attenuation characteristics. Prime non-equivalent prime numbers (like 7, 11, 13, 17, 19, and 23) help reduce the simple fraction interactions between the rotor and stator. As another example, slowing down the fluid by rapidly increasing the flow area can cause boundary layer separation, backflow, and turbulent losses. Pressure loss recovery via diffusion mechanisms dictate that the angle between blades should not exceed 12 degrees. Dividing the entire circumference (360 degrees) by the sum of the blade thickness angle and the flow passage angle, the minimum number of blades for optimal diffusion can be calculated. Adding more blades than the optimal number of blades decreases the flow passage size as the pressure drop increases.

[0162] However, increasing the number of blades, which similarly distributes the force that a single blade must support and helps reduce noise, decreases the size of the flow passage through the impeller, which is disadvantageous. The inventors overcome this problem by using short / splitter blades. To minimize the choking closer to the hub, some of the blades can be truncated, called splitter blades. Splitter blades can be placed on a support disk or shroud to transfer some of their load to the hub. However, the overall bladed disk (blade disk) and shrouded impeller has a much higher moment of inertia. The inventors avoid this by supporting the splitter blades on ribs 218 as described above, which reduces the inertia on the shroud or disk, and also minimizes the choking.

[0163] The housing includes a first stator ring 281 that surrounds the first wall 273 and a second stator ring 282 that surrounds the second wall 274. Each stator ring includes an outer circumferential wall 283 and an inner circumferential wall 284. As shown, in some embodiments, the outer circumferential wall of the first stator ring and / or the second stator ring extends axially from the stator ring to form the circumferential wall 275 of the impeller chamber 20. In the illustrated embodiment, the circumferential wall 275 of the impeller chamber is integrally formed with and extends axially from the outer circumferential wall 283 of the first stator ring. The outer circumferential wall 284 of the second stator ring 282 of the second housing portion 272 abuts the circumferential wall 275 of the impeller housing 20 of the first housing portion 271. The first housing portion 271 and the second housing portion 272 can be held together by a bayonet, a protrusion, a snap fit, a glue, an ultrasonic or friction weld, or any other suitable means. The stator rings are stationary rings of the flow path.

[0164] In each of the first stator ring 281 and the second stator ring 282, curved passages, e.g., 285, 286 (see FIG. 16 ) are formed between the inner circumferential wall 283 and the outer circumferential wall 284 for receiving and slowing air flow from the impeller 215 to create pressure. Thus, instead of a volute chamber as in the previously described embodiments, in the axial outlet embodiments, each of the first stator ring 281 and the second stator ring 282 provides a ring of small volute chambers or volute passages 285, 286 spaced circumferentially in the ring. The volute passages 285, 286 are located radially outward of the impeller 215, or adjacent to or at a radially outer periphery of the impeller blades 216, 216b of the impeller. FIG. 13 to FIG. 19

[0165] The first stator ring 281 and the second stator ring 282 provide first axial outlets 285 and second axial outlets 286. The volute passages 285, 286 of the first stator ring 281 and the second stator ring 282 provide the first axial outlets and the second axial outlets. Thus, each of the first axial outlets and the second axial outlets includes a plurality of outlet passages, each outlet passage being a volute passage. The volute passage has an increasing area through the volute passage perpendicular to the direction of air flow, such that the velocity of the air flow decreases along the volute passage to increase the pressure of the flow. For example, the circumferential or radial width, or both, can increase in size from the impeller chamber end of the volute passage to the outlet end of the volute passage.

[0166] ​In comparison to the spiral path 286 of the second stator ring 282, the spiral path 285 of the first stator ring 281 is arranged to receive a greater portion of the tangential velocity component of the air flow from the impeller 215 when the impeller is rotating in the first rotational direction. And, in the case where the impeller is rotating in the opposite second rotational direction, the spiral path 286 of the second stator ring 282 is arranged to receive a greater portion of the tangential velocity component of the air flow from the impeller 215 in comparison to the spiral path 285 of the first stator ring 281. In some embodiments, the spiral path 285 of the first stator ring 281 extends from the impeller chamber 20 to receive at least a substantial portion of the tangential velocity component of the air flow generated by the impeller 215 when rotating in the first rotational direction, and the spiral path 286 of the second stator ring 282 extends from the impeller chamber 20 to receive at least a substantial portion of the tangential velocity component of the air flow generated by the impeller 215 when rotating in the second rotational direction. Thus, by simply changing the rotational direction of the impeller 215 by changing the rotational direction of the motor 225, the air flow can be directed primarily from either the first axial outlet 285 or the second axial outlet 286 of the housing. In preferred embodiments, the impeller 215 is a symmetrical impeller and the first stator ring 281 and the second stator ring 282 are identical, but one stator ring is flipped 180 degrees about the rotational axis of the impeller relative to the other stator ring, such that rotation of the impeller in the first rotational direction produces a first gas flow from the first outlet and a second gas flow from the second outlet, and rotation of the impeller in the opposite second rotational direction produces the first gas flow from the second outlet and the second gas flow from the first outlet. The first gas flow is greater than the second gas flow. In other words, for a given impeller speed, a particular flow is provided via the first outlet 285 in the first rotational direction, and the same flow is provided by the second outlet 286 in the second rotational direction. However, in alternative embodiments, the impeller and / or stator rings can be arranged to provide different flows from the first and second axial outlets in the first and second rotational directions for a given speed.

[0167] As FIG. 16 As best shown, the spiral path 285 in the first stator ring 281 curves from the impeller chamber 20 in a tangential direction of the impeller 215 rotating in the first rotational direction and towards the first axial direction I of the blower. The spiral path 286 in the second stator ring 282 curves from the impeller chamber 20 in an opposite tangential direction of the impeller rotating in the opposite second rotational direction and towards the second axial direction II of the blower. In other words, the spiral path 285 of the first stator ring curves from the first axial direction I towards the tangential direction of the impeller rotating in the second rotational direction, and the spiral path 286 of the second stator ring 282 curves from the second axial direction II towards the opposite tangential direction of the impeller rotating in the first rotational direction.

[0168] And asFIG. 16 Best shown, in each stator ring 281, 282, each scroll path 285, 286 is separated from an adjacent scroll path by a curved rib or vane 287. In some embodiments, each curved rib 287 has a width extending in a circumferential direction of the stator ring that increases along an axial length of the rib from a volute chamber toward an axial outlet end of the rib. In some embodiments, the circumferential width of the curved rib 287 tapers to a point at the volute chamber end of the rib.

[0169] A power supply and controller are used to control the motor 225 to rotate the impeller to produce a desired output air flow (both pressure and / or flow). Air is drawn in through the openings 213, 214 forming axial inlets by rotation of the impeller, including above the motor to provide cooling, and is directed via the impeller vanes to the first stator ring 281 and the second stator ring 282. In a first rotational direction, the tangential velocity component of the air flow produced by the impeller received by the first stator ring 281 is greater than the second stator ring 282, such that greater pressure / flow is produced at the first axial outlet 285 than at the second axial outlet 286. In a second rotational direction, the tangential velocity component of the air flow produced by the impeller received by the second stator ring 282 is greater than the first stator ring 281, such that greater pressure / flow is produced at the second axial outlet 286 than at the first axial outlet 285. Thus, in some embodiments, rotation of the impeller in the first rotational direction produces a first gas flow from the first outlet 285 and a second gas flow from the second outlet 286, where the first gas flow is greater than the second gas flow. Each stator ring slows the flow to produce pressure, and the flow is directed axially out of the stator ring / axial outlet of the blower.

[0170] In some embodiments, the blower can include only a single axial inlet. For example, the blower can include only the first axial inlet 213, which includes gaps or openings 213 between ribs 278 that support the first hub 276 from the first annular wall 273. The second wall 274 can be a disk or plate or continuous cover extending within the circumferential wall 275 of the housing 270, with the second central hub 277 formed at the center of the second wall 274 and without ribs and corresponding openings around the second central hub. Alternatively, the blower can include only the second axial inlet 214, which includes gaps or openings 214 between ribs 279 that support the second hub 277 from the second annular wall 274. The first wall 273 can include an annular wall segment and a recessed wall segment radially within the annular segment for receiving the motor 225, with the first central hub 276 formed at the center of the recessed segment and without ribs and corresponding openings around the first central hub.

[0171] Referring to FIG. 19In another alternative, the stub shafts can not extend through the bearings. Rather, each stub shaft can only partially extend into the bearing (e.g., see stub shaft 269c), or just contact the bearing (e.g., see stub shaft 269d). These arrangements still provide sufficient support and allow rotation.

[0172] Other topologies of the motor are possible, and those described are merely exemplary. For example, a brushed or brushless DC motor, AC motor, inductive motor, or variable reluctance motor can be used. The rotor and stator can take other forms of the above.

[0173] The described dual axial embodiment has a number of advantages. It provides a blower with a reduced footprint and / or planform. The smaller footprint allows for a smaller housing. One reason for the smaller footprint is that the stator ring allows for the omission of one or more volute chambers, thereby reducing the overall diameter and / or height of the blower, and also increasing the ratio of blade length to housing diameter (that is, the space for blade length is not reduced due to the presence of volute chambers, thereby allowing the blade length to use more of the available footprint diameter than a housing with volute chambers).

[0174] The described embodiment also allows for the use of a smaller impeller (that is, smaller diameter, thickness, and / or weight). This in turn results in a smaller / lighter blower and / or a blower with lower inertia. The smaller / lighter topology enables the blower to be used for portable, miniaturized, and / or head or mask CPAP, high flow therapy, or other respiratory devices.

[0175] As an example, the impeller can have a diameter of about 47 mm inside a ring of about 48 mm diameter, thereby providing a ratio of blade length to housing diameter of 98%. Another example is a blade of about 18 mm in a housing of about 20 mm radius, for a ratio of 90%. These are merely illustrative examples, and other diameters are possible. Typical envelope / footprint of the blower can be:

[0176] • Diameter: <= about 52 mm

[0177] • Height: <= about 20 mm

[0178] • Weight: <= about 50 g (e.g., 27 g)

[0179] These small impellers are not suitable for the above applications. This is because, when operated at typical speeds (revolutions per minute), the air flow characteristics are insufficient to provide the required therapy (e.g., the flow and / or pressure generated by smaller impellers of this nature are insufficient). Furthermore, it is not possible to run these impellers at high speeds to generate the required flow and / or pressure because these speeds result in multiple disadvantages. For example, as the speed increases, the bearings operate at higher speeds and / or temperatures. This requires the use of more expensive special bearings, such as ceramic bearings, air bearings, or fluid bearings. It is necessary to use smaller diameter bearing races and bearings to reduce the speed of the bearings. This results in a necessary decrease in the shaft diameter so that the shaft can still pass through the center of the bearing race. When using a smaller diameter shaft, it is more difficult to attach the impeller and / or rotor magnet, e.g., by integral design or friction fit. The manufacturing tolerances are too precise to be completed in a practical manner. Thus, it has been impractical to house smaller impellers to date. Another alternative is to use a blower with multiple impeller stages, however such blowers are more expensive, larger, and more difficult to manufacture.

[0180] FIG. 13 Embodiments of the present application can overcome one or more of these problems and allow for the use of smaller impellers in a single stage blower. The shaft used is hollow, or at least partially hollow. The bearings fit into the interior of the shaft. This allows two things. First, it allows the shaft diameter to be the same or similar to previous sizes so that the impeller and / or rotor (or magnet) can be integrated into or fit onto the shaft in the usual manner; and second, because the bearings are disposed internally, it allows for the use of smaller diameter bearings (while the diameter of the shaft remains the same). This then allows the impeller to be rotated at a higher speed to generate the required flow and / or pressure with a smaller diameter impeller. However, despite the impeller / shaft running at a higher speed, the smaller diameter bearings run at a lower speed than the larger diameter bearings conventionally used, which avoids the problems of higher speeds mentioned above. Thus, the short shaft allows for connection to the internal races of the bearings, and the compliance / resilience of the short shaft allows for compliance when the shaft spins. The arrangement also reduces or eliminates eddy currents in the shaft and / or bearings. Eddy currents can cause the bearings to deteriorate.

[0181] Additionally, the short blades and increased number and / or size of air inlets allow for more pressure to be generated from a smaller blade length.

[0182] The axial outlet eliminates the need for a tangential outlet tube, which can increase the footprint of the blower.

[0183] The arrangement also allows for a single stage (dual) axial input / dual axial output blower that provides a reduced footprint or lower (lower) profile. The described embodiments do not have a volute chamber that is also reduced in size. The stator ring creates static pressure. In some embodiments, the axial air flow inlet allows for cooling of the motor stator.

[0184] In reference now to FIG. 20 to FIG. 24 In another embodiment described, a dual axial outlet blower 310 can include two impellers 315a and 315b, as shown in FIG. 23 The two impeller shafts are axially spaced apart. The housing 370 includes a first impeller chamber 20a for receiving the first impeller 315a and a second impeller chamber 20b for receiving the second impeller 315b.

[0185] The housing includes a first wall 373a and a second wall 374a that are axially spaced apart by a circumferential wall 375a. The first and second walls and the circumferential wall combine to form the first impeller chamber 20a for receiving the first impeller 315a, as described above with respect to the previous single impeller embodiments.

[0186] Additionally, the housing 370 includes a third wall 373b and a fourth wall 374b that are axially spaced apart by a second circumferential wall 375b. The third and fourth walls and the second circumferential wall combine to form the second impeller chamber 20b for receiving the second impeller 315b. In the illustrated embodiment, the first, second, third, and fourth walls are annular. The first impeller chamber 20a and the second impeller chamber 20b can be identical, but one impeller chamber is flipped 180 degrees about the rotational axis of the impeller relative to the other impeller chamber.

[0187] The housing also includes a first central hub 376 and a second central hub 377. In some embodiments, the first central hub is connected to the inner periphery of the first annular wall 373a via radial ribs 378. In some embodiments, the second central hub 377 is connected to the inner periphery of the third annular wall 373b via ribs 379. Preferably, the ribs connecting each hub to the respective annular wall extend radially between the hub and the annular wall.

[0188] The first hub 376 provides at least partial support for the first bearing 229, which in turn provides support for the rotor 226 and dual impeller 315a, 315b assembly. The openings or gaps 313 between the ribs 378 provide the first axial inlet. The second central hub 377 provides at least partial support for the second bearing 229, which in turn also provides support for the rotor 226 and dual impeller 315a, 315b assembly. In some embodiments, the openings or gaps 314 between the ribs provide the second axial inlet.

[0189] In FIG. 20In embodiments of the housing 370 includes a single motor chamber 60. A motor including a stator 227 and a rotor 226 is located in the motor chamber. The motor chamber and motor are axially located between the first impeller chamber 20a and the second impeller chamber 20b. By way of example and as shown, the motor chamber 60 can be provided by a circumferential wall extending between the second wall and the fourth wall of the housing 370. The rotor 226 is coupled to the first impeller 315a and the second impeller 315b such that the rotor and the first and second impellers rotate together.

[0190] FIG. 24 An exemplary rotor and dual impeller configuration for the blower 310 is shown. The rotor and impeller arrangement can be similar or identical to the arrangements described above with reference to FIG. 17 The shaft 328 has sufficient length to support the rotor magnet 226a along the shaft 328 at the middle and where the first impeller 315a and the second impeller 315b are located at corresponding ends of the shaft or on the shaft on either axial side of the rotor magnet. The shaft can be formed in two parts that are press fit or otherwise secured within or to the rotor. Each part of the shaft can be press fit or otherwise connected to or formed integrally with a respective one of the two impellers. The rotor is located inside the stator 227 and is supported on stub shafts 269a, 269b at the first hub 376 and the second hub 377 by bearing elements as described for the previous embodiments of the blower 310 including a single impeller. FIG. 13 A resilient mount can be provided to mount the stator within the motor chamber 60.

[0191] The first impeller 315a and the second impeller 315b can be identical, but one of the impellers is flipped 180 degrees about the rotational axis of the impeller relative to the other impeller. FIG. 23An exemplary first and second impeller (where the first and second impellers are identical) are shown in greater detail. The impellers 315a, 315b include a hub portion 317 and flat forward-swept (full length) blades (sometimes referred to as "vanes") 316 that extend radially from and are connected to the hub portion. (Alternatively, the blades can be swept aft or radially swept). Each blade includes a vertical (parallel to the axis of rotation) flat portion that extends from the hub 317. Annular ribs / rings 318 are formed into and extend between the blades 316 to provide rigidity at the periphery of the blades. The rings are curved toward the corresponding stator ring outlet 381, 382 to provide rigidity to the blades and also to direct the air flow through the corresponding stator ring. A plurality of stub (partial length) blades 316b (also referred to as "splitter blades") that extend partially to the hub are spaced between the full length blades 316. In the exemplary embodiment shown, there are three stub blades between each pair of adjacent full length blades. Annular ribs 318 are also formed into and extend between the stub blades 316b, thereby supporting them. The stub blades provide additional pressure that is typically achieved with additional blades without the need for material extending to the hub, which reduces the air space at the hub. Reducing the air space at the hub reduces the maximum flow capacity of the blower 310. If the number of blades is too great (and therefore the air space at the hub is too small due to the large number of blades), then the inlet flow is choked, thereby limiting the outlet air flow of the blower. Thus, FIG. 23 The impellers have the same associated benefits as described above with respect to the single impeller dual axial outlet blower described above with reference to FIG. 13 to FIG. 19 However, the forward curved blades are further optimized with respect to the direction of rotation to preferentially produce pressure depending on the direction of rotation.

[0192] The housing includes a first stator ring 281 that surrounds the first annular wall 373 and a second stator ring 282 that surrounds the second annular wall 373b. The stator rings 281, 282 are as described above with respect to the single impeller embodiment of FIG. 13 The first impeller 315a is arranged such that the rings 318 of the impeller are curved to the volute path 285 of the first stator ring 281 and the second impeller 315b is arranged such that the rings 318 of the impeller are curved to the volute path 286 of the second stator ring 282.

[0193] When the rotor 226 and first and second impeller assembly 315a, 315b rotate, the first impeller generates pressure and flow at the first stator ring 281 and the second impeller generates pressure and flow at the second stator ring 282. However, the blades of the first impeller 315a sweep forward or curve in the forward direction relative to the first direction of rotation and the blades of the second impeller 315b sweep backward or curve in the backward direction relative to the first direction of rotation. Due to the opposite curving of the blades of the first and second impellers, the pressure generated by the first impeller at the first stator ring 281 is greater than the pressure generated by the second impeller at the second stator ring 282 when rotating in the first direction of rotation. And, the pressure generated by the second impeller at the second stator ring 282 is greater than the pressure generated by the first impeller at the first stator ring 281 when rotating in the second direction of rotation. Further, the volute path of the first stator ring is arranged to receive a greater portion of the tangential velocity component of the air flow from the first impeller when the first impeller is rotating in the first direction of rotation than when rotating in the second direction of rotation. And, the volute path of the second stator ring is arranged to receive a greater portion of the tangential velocity component of the air flow from the second impeller when the second impeller is rotating in the second direction of rotation than when rotating in the first direction of rotation. Thus, when the rotor and first and second impeller assembly rotate in the first direction of rotation, greater pressure and / or flow is generated from the first axial outlet than the second axial outlet. And, when the rotor and second and second impeller assembly rotate in the second direction of rotation, greater pressure and / or flow is generated from the second axial outlet than the first axial outlet. Thus, in some embodiments, rotation of the impellers in the first direction of rotation generates a first gas flow from the first outlet 285 and a second gas flow from the second outlet 286, where the first gas flow is greater than the second gas flow.

[0194] In some embodiments, the vortex path 285 of the first stator ring 281 extends from the first impeller chamber 20a to receive at least a substantial portion of the tangential velocity component of the airflow generated by the first impeller when rotating in a first rotation direction, and the vortex path 286 of the second stator ring 282 extends from the second impeller chamber 20b to receive at least a substantial portion of the tangential velocity component of the airflow generated by the second impeller when rotating in a second rotation direction. Therefore, by simply changing the rotation direction of the motor to alter the rotation direction of the rotor and the first and second impeller assemblies, the airflow can be guided primarily from either the first or second axial outlet of the housing. In a preferred embodiment, the first impeller 315a and the first stator ring 281 are identical to the second impeller 315b and the second stator ring 282, but one impeller and stator ring are rotated 180 degrees about the axis of rotation of the impeller relative to the other impeller and stator ring. This causes rotation of the impeller and rotor assembly in a first direction of rotation to produce a first gas flow from a first outlet and a second gas flow from a second outlet, and rotation of the impeller in the opposite second direction of rotation to produce a first gas flow from a second outlet and a second gas flow from a first outlet. The first gas flow is greater than the second gas flow. In other words, for a given impeller speed, a specific flow rate is provided via the first outlet in the first direction of rotation, and the same flow rate is provided by the second outlet in the second direction of rotation. However, in an alternative embodiment, the impeller and / or stator ring may be arranged to provide different flows from the first axial outlet and the second axial outlet in the first and second directions of rotation for a given speed.

[0195] A power supply and controller are used to control the motor to rotate the impeller, thereby generating the desired output airflow (both pressure and / or flow rate). Air is drawn in through an opening in the axial inlet by the rotation of the rotor and the dual impeller assembly, and guided via the first and second impellers to the first and second stator rings. Each stator ring slows the flow to generate pressure, and the flow is axially directed out of the blower's stator ring / axial outlet.

[0196] The aforementioned axial outlet blower may further include a first outlet manifold and a second outlet manifold. The first outlet manifold may include an inlet for receiving flow from outlet 282 of the first stator ring and directing the flow from the first stator ring to the outlet of the first outlet manifold. Similarly, the second outlet manifold may include an inlet for receiving flow from outlet 282 of the second stator ring and directing the flow from the second stator ring to the outlet of the second outlet manifold. The outlet of each of the first and second outlet manifolds may be a single outlet and may be an axial outlet.

[0197] In the above description, wherever references have been made to an integral or component having a known equivalent, such integrals are incorporated herein as if they were referred to separately.

[0198] The above description of the application includes the preferred forms thereof. Modifications can be made to the application without departing from the scope thereof as defined by the appended claims.

Claims

1. A biaxial outlet blower, the blower comprising: Impeller, and The housing includes an impeller chamber in which the impeller rotates, an axial inlet, and a first axial outlet and a second axial outlet. Wherein, when the impeller rotates along the first rotation direction, the gas flow from the first axial outlet is greater than the gas flow from the second axial outlet, and When the impeller rotates in the second rotation direction, the gas flow from the second axial outlet is greater than the gas flow from the first axial outlet.

2. The blower as described in claim 1, wherein: The rotation of the impeller along the first rotation direction generates a first gas flow from the first axial outlet and a second gas flow from the second axial outlet, and The rotation of the impeller along the second rotation direction generates a first or third gas flow from the second axial outlet and a second or fourth gas flow from the first axial outlet. The flow rate of the first gas stream is greater than the flow rate of the second gas stream, and the flow rate of the third gas stream is greater than the flow rate of the fourth gas stream.

3. The blower as described in claim 1 or 2, wherein, The impeller is symmetrical, so that the rotation of the impeller in the first direction of rotation results in a greater gas flow from the first axial outlet than from the second axial outlet. The rotation of the impeller along the second rotation direction results in a gas flow from the second axial outlet being greater than the gas flow from the first axial outlet.

4. The blower as described in claim 3, wherein, The impeller blades are radially extending blades that are straight or otherwise shaped to produce a given flow rate for a given rotational speed, regardless of the direction of rotation.

5. The blower as described in claim 1 or 2, wherein, The impeller is asymmetrical, so that the rotation of the impeller in the first direction of rotation results in a greater gas flow from the first axial outlet than from the second axial outlet. The rotation of the impeller along the second rotation direction results in a gas flow from the second axial outlet being greater than the gas flow from the first axial outlet.

6. The blower as described in claim 5, wherein, The impeller blades are angled, curved, and / or otherwise shaped to allow the impeller to preferentially rotate in one direction.

7. The blower as described in claim 1 or 2, wherein, The blower includes a motor for driving the rotation of the impeller, and the housing includes the impeller chamber and a motor chamber for supporting the motor within the housing.

8. The blower as described in claim 1 or 2, wherein, The impeller is a centrifugal impeller.

9. The blower as described in claim 1 or 2, wherein, The first axial outlet is an axial outlet on a first side of the blower, and the second axial outlet is an axial outlet on a second side of the blower.

10. The blower as described in claim 1 or 2, wherein, The blower includes a first impeller and a second impeller, and the housing includes a first impeller chamber in which the first impeller rotates and a second impeller chamber in which the second impeller rotates. The first impeller and the second impeller are rotatably connected so as to rotate together. The first impeller generates a gas flow from the first axial outlet when the first impeller and the second impeller rotate in the first rotation direction, and the second impeller generates a gas flow from the second axial outlet when the first impeller and the second impeller rotate in the second rotation direction.

11. The blower as claimed in claim 10, wherein, The blower includes a motor for driving the rotation of the first impeller and the second impeller, the motor including a rotor and a stator, wherein the first impeller and the second impeller are rotatably coupled to the rotor.

12. The blower as claimed in claim 11, wherein, The rotor is axially positioned between the first impeller and the second impeller, and The housing includes a motor chamber for the motor, the motor chamber being axially positioned between the first impeller chamber and the second impeller chamber.

13. The blower as described in claim 1 or 2, wherein, The housing includes a first stator ring and a second stator ring, each stator ring including multiple vortex paths, the first axial outlet including the vortex path of the first stator ring, and the second axial outlet including the vortex path of the second stator ring.

14. The blower as claimed in claim 13, wherein, Apart from the vortex path of the stator ring, the blower does not have a vortex chamber.

15. The blower as claimed in claim 13, wherein, Each stator ring includes multiple curved blades, and each of the vortex paths is separated from the adjacent vortex paths in the stator ring by one of the curved blades.

16. The blower as claimed in claim 15, wherein, Each stator ring includes the plurality of curved blades, which are circumferentially spaced apart from the radial outer side of a corresponding impeller of the first impeller and the second impeller, or adjacent to or located at the radial outer periphery of a corresponding impeller of the first impeller and the second impeller.

17. The blower as claimed in claim 13, wherein, The vortex paths of the first stator ring and the second stator ring provide the first axial outlet and the second axial outlet.

18. The blower as claimed in claim 13, wherein, Each vortex path has an increased region perpendicular to the airflow direction that at least partially passes through the vortex path, such that the airflow velocity decreases along the vortex path to increase the pressure of the flow.

19. The blower as claimed in claim 18, wherein, Each vortex path has an increased region perpendicular to the airflow direction, provided by circumferential and / or radial width, which increases in size from the impeller chamber end of the vortex path to the outlet end of the vortex path.

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