Respiratory apparatus

Abstract

A head-mountable flow generator is configured to deliver a flow of breathable gas at a continuously positive pressure with respect to ambient air pressure to a patient interface in communication with an entrance to a patient's airways including at least an entrance of the patient's nares, while the patient is sleeping, to ameliorate sleep disordered breathing. The flow generator includes a motor, an impeller assembly and housing that encases the motor and the impeller assembly. The housing is configured to be mounted on the patient's head and comprises an inlet to receive the flow of breathable gas and a pair of opposing outlets to deliver the flow of breathable gas. In addition, the impeller assembly is configured to pressurize the flow of breathable gas received from the inlet, and the housing is configured to convey the pressurized flow of breathable gas through both outlets.

Claims

1. A respiratory apparatus configured to supply pressurized respiratory gas to a patient's airways, the respiratory apparatus comprising: a flow generator configured to be mounted on a patient's head and comprising a blower assembly enclosed within a housing, the housing comprising a pair of outlet ports on opposite sides of the housing, the outlet ports being configured to discharge the flow of respiratory gas pressurized by the blower; a patient interface configured to sealingly engage the patient's face; and a pair of conduits extending along the sides of the patient's face and connecting the flow generator to the patient interface to deliver the pressurized flows of respiratory gas to the patient interface; and headgear configured to hold each conduit against the patient's face wherein each conduit is connected to a respective one of the outlet ports by a respective connector, and wherein each of the connectors is configured to reduce the transmission of and/or isolate vibrations generated by the flow generator.

2. The respiratory apparatus of claim 1, wherein the connectors are soft grommets.

3. The respiratory apparatus of claim 1, wherein the connectors are bellows-type connectors.

4. The respiratory apparatus of claim 1, wherein the conduits are formed of soft material configured to reduce and/or isolate vibrations generated by the flow generator.

5. The respiratory apparatus of claim 4, wherein the conduits are formed of silicone rubber.

6. The respiratory apparatus of claim 1, wherein the flow generator is configured to allow the patient to sleep on their side without the position of the flow generator on the patient's head being disturbed.

7. The respiratory apparatus of claim 1, wherein a head-engaging side of the flow generator is curved from a posterior side to an anterior side.

8. The respiratory apparatus of claim 7, wherein the head-engaging side of the flow generator is curved in a lateral direction from a right side to a left side.

9. The respiratory apparatus of claim 1, wherein the patient interface is a full face mask or a nasal mask.

10. The respiratory apparatus of claim 1, wherein the patient interface comprises nasal pillows.

11. The respiratory apparatus of claim 1, wherein the blower comprises an impeller.

12. A respiratory apparatus configured to supply pressurized respiratory gas to a patient's airways, the respiratory apparatus comprising: a flow generator comprising a blower enclosed by a housing with a pair of outlet ports, the blower being configured to pressurize the flow of respiratory gas, each outlet port being configured to discharge the pressurized flow of respiratory gas; a patient interface configured to sealingly engage the patient's face and comprising a pair of gas inlets; a pair of conduits extending along the sides of the patient's face, each conduit connecting a respective one of the outlet ports to a corresponding one of the patient interface gas inlets to deliver the pressurized flow of respiratory gas from the flow generator to the patient interface; and headgear attached to the flow generator and the conduits and configured to secure the flow generator, the patient interface, and the conduits to the patient's head, wherein each outlet port comprises a respective connector configured to connect a respective one of the pair of conduits to a corresponding outlet port, and wherein each of the connectors is configured to reduce the transmission of and/or isolate vibrations generated by the flow generator.

13. The respiratory apparatus of claim 12, wherein the connectors are soft grommets.

14. The respiratory apparatus of claim 12, wherein the connectors are bellows-type connectors.

15. The respiratory apparatus of claim 12, wherein the conduits are formed of soft material configured to reduce and/or isolate vibrations generated by the flow generator.

16. The respiratory apparatus of claim 12, wherein each conduit comprises a headgear connector configured to receive a respective headgear strap of the headgear.

17. The respiratory apparatus of claim 16, wherein the headgear connectors are located at midpoints on the conduits.

18. The respiratory apparatus of claim 12, wherein the gas outlets of the flow generator are located on opposite sides of the flow generator.

19. The respiratory apparatus of claim 12, wherein the majority of the flow generator is located posterior to the gas outlets.

20. The respiratory apparatus of claim 12, wherein the gas outlets are positioned at midpoints on opposing side surfaces of the flow generator.

21. The respiratory apparatus of claim 12, wherein the patient interface comprises a full face mask, a nasal mask, or nasal pillows.

22. The respiratory apparatus of claim 12, wherein the blower comprises an impeller.

23. The respiratory apparatus of claim 12, wherein the outlet ports are located on opposite sides of the housing.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The accompanying drawings facilitate an understanding of the various embodiments described herein. In such drawings:

(2) FIG. 1 schematically illustrates a respiratory apparatus according to a sample embodiment;

(3) FIG. 2 schematically illustrates a respiratory apparatus according to another sample embodiment;

(4) FIG. 3 schematically illustrates a flow generator housing or casing for a respiratory apparatus according to a sample embodiment;

(5) FIG. 4 schematically illustrates a blower assembly of a flow generator for a respiratory apparatus according to a sample embodiment;

(6) FIG. 5 schematically illustrates a side elevation view of the blower assembly of FIG. 4;

(7) FIG. 6 schematically illustrates an opposite side elevation view of the blower assembly of FIG. 4;

(8) FIG. 7 schematically illustrates a front side election view of the blower assembly of FIG. 4;

(9) FIG. 8 schematically illustrates a bottom view of the blower assembly of FIG. 4;

(10) FIG. 9a schematically illustrates a perspective view of the blower assembly of FIG. 4;

(11) FIG. 9b schematically illustrates an exploded assembly view of the blower assembly of FIG. 9a;

(12) FIG. 10 schematically illustrates a cross-section of the blower assembly of FIG. 4;

(13) FIG. 11 schematically illustrates a cross-section of the blower assembly of FIG. 4;

(14) FIG. 12 schematically illustrates a cross-section of a first impeller of the blower assembly of FIG. 4;

(15) FIG. 13 schematically illustrates a perspective view of the first impeller of FIG. 12;

(16) FIG. 14 schematically illustrates a stator of the blower assembly of FIG. 4;

(17) FIG. 15 schematically illustrates a second impeller of the blower assembly of FIG. 4;

(18) FIG. 16 schematically illustrates a respiratory apparatus according to another sample embodiment;

(19) FIG. 17 schematically illustrates a respiratory apparatus according to another sample embodiment;

(20) FIG. 18 schematically illustrates a flow generator according to another sample embodiment;

(21) FIGS. 19 and 20 schematically illustrate a respiratory apparatus incorporating the flow generator of FIG. 17; and

(22) FIG. 21 schematically depicts a respiratory apparatus according to another sample embodiment.

DETAILED DESCRIPTION OF ILLUSTRATED EMBODIMENTS

(23) The following description is provided in relation to several embodiments which may share common characteristics and features. It is to be understood that one or more features of any one embodiment may be combinable with one or more features of the other embodiments. In addition, any single feature or combination of features in any of the embodiments may constitute additional embodiments.

Respiratory Apparatus First Embodiment

(24) Referring to FIG. 1, a respiratory apparatus for delivering a flow of pressurized breathable gas to a patient 2, for example to treat SBD, such as OSA, comprises a flow generator 4 to generate the flow of pressurized breathable gas. The flow generator 4 is contained in a flow generator housing or casing 6 that is anthropometrically configured to engage the head of the patient 2. As shown in FIG. 1, the flow generator housing 6 is configured to engage the top of the patient's head to permit the patient to sleep on the patient's side without disturbing the positioning of the flow generator housing 6. As shown in FIG. 1, the flow generator housing may have a curvature in the back to front direction of the housing, and a curvature in a lateral direction, i.e. in a direction from one side of the patient's head to the other side.

(25) The flow generator 4 delivers a flow of pressurized breathable gas through delivery tubes or conduits 8 which are connected to the flow generator housing 6 for receipt of the flow of pressurized breathable gas. The flow of pressurized breathable gas is delivered by the delivery conduits 8, which extend from the flow generator housing 6 along the sides of the face of the patient 2, to a patient interface 10 that is in contact with the nasal passageways of the patient 2. As shown in FIG. 1, the patient interface 10 may support nasal pillows or prongs 12 which are in sealing contact with the nares of the patient's nose. It should be appreciated, however, that the delivery conduits 8 may deliver the flow of pressurized breathable gas to a nasal mask which covers only the nose of the patient. As another example, the delivery conduits 8 may be connected to a full face mask which covers the nose and mouth of the patient. As an even further example, the delivery conduits 8 may be connected to a patient interface that includes a mouth covering portion having nasal pillows or prongs extending from the mouth covering portion for sealing engagement with the nose of the patient. It should be even further appreciated that the patient interface may include nasal cannulae which do not sealingly engage with the nose of the patient.

(26) The conduits 8 may be formed of soft material, for example silicone rubber, to isolate vibrations from the flow generator 4. The conduits 8 may also be connected to the flow generator by a connector configured to isolate vibrations, for example a soft grommet or a bellows type connector. The conduits 8 may also be the conduits as disclosed in U.S. Patent Application Publication 2008/0060649 A1, the entire contents being incorporated herein by reference.

Respiratory Apparatus Second Embodiment

(27) Referring to FIG. 2, a respiratory apparatus according to another sample embodiment includes strap attachment portions 14 provided on the delivery conduits 8. A strap, or headgear system, may be connected to the strap attachment portions to provide additional securement of the respiratory apparatus to the head of the patient. As shown in FIG. 2, the flow generator housing 6 may be configured to extend towards the back of the head of the patient 2, but may not extend as far forward on the head of the patient 2 as the flow generator housing 6 of the sample embodiment of FIG. 1.

(28) Referring to FIG. 3, the flow generator housing 6 may be configured to support a voltage regulator 16, a motor controller 18 and a power source 20. The power source 20 may comprise a battery, or a plurality of batteries. For example, the battery or batteries may be configured as lithium polymer batteries having a volumetric energy density of about 250-530 Wh/L, for example about 270 to 400 Wh/l, as another example about 330 Wh/l and a gravimetric energy density of about 150-200 Wh/kg, for example about 155 to 175 Wh/kg, as another example about 163 Wh/kg. Such a battery would have, for example, a battery volume of 112 cm.sup.2 and a weight of 225 g. The lithium polymer battery may comprise 32 lithium polymer battery cells that would provide approximately 8 hours of power to an electric motor of a blower assembly of the flow generator 4 for generating a flow of about 40-601/min, for example, 50 l/min at a pressure in a range of about 2-12 cm H.sub.2O, for example about 6 cm H.sub.2O. The battery cells may be flexible and thus may be curved for insertion into the housing 6 which may be curved to match the shape of the top of the patient's head.

(29) The lithium polymer battery may have a life cycle of approximately 500 charges. The flow generator housing 6 may be provided with a docking station configured to charge the battery when the housing 6 is placed in the station.

(30) Flow Generator and Blower Assembly

(31) Referring to FIGS. 4 and 5, the flow generator 4 comprises a blower assembly 22. The blower assembly 22 comprises a blower assembly upper housing 24 and a blower assembly lower housing 34. A blower assembly inlet 26 is provided in the upper housing 24. It should be appreciated that the use of the terms “upper” and “lower” refer to the orientation of the blower assembly housing shown in the drawings and not necessarily to any required orientation of the blower assembly. As shown in FIGS. 4-9b, the blower assembly 22 comprises a first outlet 28 and a second outlet 30 on opposite sides of the lower housing 34. An electrical connector 32 is provided between the upper housing 24 and the lower housing 34 to provide power to an electric motor 44 (FIG. 10).

(32) Referring to FIG. 10, the blower assembly 22 comprises the upper housing 24 and the lower housing 34 and a middle housing 40 provided between the upper housing 24 and the lower housing 34. A stator 38 is supported on the middle housing 40. The electric motor 44 is supported by the stator 38.

(33) The electric motor 44 includes a shaft 45 that extends from opposite sides of the electric motor 44. The shaft 45 may be generally coincident with an axis of the motor 44. A first impeller 36 is connected to the shaft 45 for rotation with the shaft upon actuation of the electric motor 44. A second impeller 42 is connected to the opposite side of the shaft 45 and thus the opposite side of the motor for rotation with the shaft 45 upon actuation of the electric motor 44. The motor 44 may be selected from a variety of commercially available motors, for example from the motors supplied by Maxon Motor of Switzerland.

(34) Upon actuation of the electric motor 44, the shaft 45 rotates and causes rotation of the first impeller 36 and the second impeller 42. As shown in FIGS. 10 and 11, rotation of the impellers 36, 42 causes a flow F of air into the inlet 26 of the blower assembly 22. The flow enters the upper housing 24 through the inlet 26 and proceeds around the first impeller 36 and is forced down towards the stator 38. The flow then flows around the stator 38 and is forced down through the middle housing 40 towards the second impeller 42. The second impeller 42 forces the flow back up over the periphery of the middle housing 40 and out through the first outlet 28 and the second outlet 30.

(35) The inlet 26 of the blower assembly 22 has an axis that is generally coincident with the axis of the electric motor 44. The axis of the first outlet 28 and the axis of the second outlet 30 are generally tangential to circumference of the housings 24, 34 and generally perpendicular to the axis of the blower assembly 22 and/or the motor 44. The use of the axially coincident inlet 26, the tangential outlets 28, 30, and the two impellers 36, 42 provides a flow path that is folded back on itself, as shown in FIGS. 10 and 11, which utilizes what would otherwise be dead space in the blower assembly and thus reduces the overall size of the blower assembly 22. The reduced size of the blower assembly 22 provides smaller gaps and apertures along the flow path which reduces, or eliminates, turbulence and noise, and enables a low flow Reynolds number for the flow F from the blower assembly 22. The blower assembly 22 may be adapted such that the path of the flow F extends along a first section from the inlet 26 having an axis that is generally parallel and/or coincident to the axis of the electric motor 44. The flow F is then directed, along a second section, radially outwardly with regard to the axis of the electric motor 44 by the first impeller 36. The flow F then extends along a third section, from the outer circumference of the first impeller 36 in a generally axial direction, and generally parallel and in the same general direction as the flow's initial direction when entering the inlet 26 along the first section. The flow F then extends, along a fourth section, radially inwardly along the stator 38. Accordingly, the flow F is folded back on itself at least once, for example from a radial outward direction around the circumference of the first impeller 36 along the second section to a radial inward direction along the fourth section.

(36) The flow F extends radially inwardly along the stator 38 generally up to the outer circumference of the motor 44. The flow F then extends along a fifth section that extends generally axially with respect to the axis of the motor 44 and along the motor in generally the same direction as the first section. The fifth section of the flow F may be defined between the motor 44 and the inner circumference of the middle housing 40. The flow F then extends a long a sixth section and is directed radially outwardly with respect to the axis of the motor 44 by the second impeller 42. Accordingly, the flow F is folded back on itself at least once, and possibly a second time, i.e. from a radial inward direction along stator 38 and along the fourth section to a radial outward direction along the second impeller 42 and the sixth section. At the outer circumferential end of the second impeller 42 the flow F extends, along a seventh section, generally axially upwardly towards the first and/or second outlet 28, 30. Thus the flow F is folded back on itself at least once, and possibly three times. The flow path F may be meandering. It should be appreciated that the description of the flow F relates to the cross sectional views shown in FIGS. 10 and 11. As shown, the flow F may be generally radially symmetrical.

(37) The outlets 28, 30 may be elliptical or oval. The use of elliptical or oval outlets reduces, or minimizes, the size of the outlets and allows the axial dimension, i.e. height, of the blower assembly 22 to be reduced, or minimized. The use of elliptical or oval outlets provides a sufficient cross sectional area to permit the flow to exit the blower assembly and also reduces sharp corners in the blower assembly. As shown, for example in FIGS. 4, 8, 9a, and 9b, there are two outlets 28, 30 symmetrically provided on the blower assembly 22. The use of two symmetrical outlets provides more outlet flow area for a given axial height than a single outlet, and lowers conducted noise. It should be appreciated that more than two outlets may be provided. It should also be appreciated that the outlets may have a 360° rotational symmetry.

(38) Referring to FIG. 12, the first impeller 36 includes a first impeller disk 46. A motor mounting portion 48 is configured for mounting the first impeller 36 to the electric motor shaft 45. As shown in FIG. 13, the motor mounting portion 48 includes an aperture 50 configured to receive the electric motor shaft 45. A plurality of vanes 52 are provided on the first impeller disk 46 to generate the flow F upon rotation of the first impeller 36. The vanes 52 direct the flow radially to the periphery of the first impeller 36 as shown in FIGS. 10 and 11. The first impeller 36 generates a flow F that is initially in the axial direction of the electric motor 44.

(39) As shown in FIG. 13, the vanes 52 of the first impeller 36 are generally straight. However, it should be appreciated that the vanes 52 may be curved. As also shown in FIG. 13, the vanes 52 may have a varying height. The height of the vanes may be largest toward the center of the first impeller disk 46 and may be smallest at the outer periphery or circumference of the first impeller disk 46. The height of the vanes for 52 may be related to the diameter of the first impeller disk 46 for providing a desired flow. The height of the vanes 52 may be optimized for the selected diameter of the first impeller disk 46 to further reduce the overall size of the blower assembly 22. The vanes 52 may be configured such that the height of the vanes 52 at their tips (i.e. at the circumferential edge of the disk 46) are the minimum height that does not choke the flow F. The “choke” is related to the cylindrical surface of the disk 46 at the circumferential edge, i.e. the outer edges of the vanes 52, and the axial height of the vanes 52 at the circumferential edge of the disk 46. In other words the “choke” is related to a cylinder of diameter equal to the outer diameter of disk 46 and which has an axial dimension (height) equal to the height of the vanes 52 at the periphery of disk 46. The lower the height of the vanes 52, the lower the Reynolds number and therefore the lower the turbulence noise.

(40) Referring to FIG. 14, the stator 38 comprises a stator disk 54 and a motor mounting portion 56 to mount the stator 38 to the electric motor 44. A plurality of vanes 58 are provided on the stator disk 54. As shown in FIG. 14, the vanes 58 are curved to fold the flow F delivered from the first impeller 36 back towards the center of the blower assembly, i.e. back toward the electric motor 44. The vanes 58 then direct the flow F in the direction of the axis of the electric motor 44 through the middle housing 40 toward the second impeller 42, as shown in FIGS. 10 and 11.

(41) Referring to FIG. 15, the second impeller 42 comprises a second impeller disk 60 and a motor mounting portion 62 configured to connect the second impeller 42 to the shaft 45 of the electric motor 44. A plurality of vanes 64 are provided on the second impeller disk 60 for directing the flow F around the middle housing 40 and out the first outlet 28 and a second outlet 30, as shown in FIGS. 10 and 11. By folding the flow F back toward the electric motor 44, and by directing it axially along the circumference of the electric motor 44 before folding the flow F back, radially outwardly be the second impeller 42, the flow F cools the motor 44 and is heated by passing the motor 44. The vanes 64 of the second impeller disk 60 may be configured in a manner similar to the vanes 52 of the first impeller disk 46. As shown in FIGS. 9b, 10 and 11, the inner ends of the vanes 64 define a diameter that is larger than the diameter of the motor 44. This allows the vanes 64 to sit, at least partly, at the same axial position as the lower section of the motor 44, which reduces the axial height of the blower assembly 22.

(42) The blower assembly may have a width of about 45-60 mm, for example about 50-55 mm, as another example about 52 mm, and a height of about 20-30 mm, for example about 23-27 mm, as another example about 25 mm. The motor may have a width of about 15-25 mm, for example about 17-23 mm, as another example about 20 mm, and a height of about 15-20 mm, for example about 17 mm. The motor may be brushless and deliver about 1-5 W shaft power, for example about 3 W. The motor may weigh about 10-20 g, for example about 13-17 g, as another example about 15 g. The blower assembly may provide a flow of about 40-601/min., for example about 45-551/min, as another example about 50 l/min., at a pressure of about 2-12 cm H.sub.2O, for example about 4-8 cm H.sub.2O, as another example about 6 cm H.sub.2O. It should be appreciated that these flow and pressure ranges are examples and the flow generator may be scaled to provide flow and pressure ranges other than the examples provided herein.

(43) The housing of the blower assembly may be configured to suppress noise generated by the motor 44. For example, a gel layer may be provided between the upper housing 24 and the lower housing 34, and/or a gel layer may be provided between the stator 38 and the motor 44 to damp vibrations and/or noise generated by the motor 44.

(44) Other modifications that may be made to the blower assembly include providing bearings to the housing 24, 34 instead of the motor 44, as disclosed in U.S. Patent Application Publication 2008/0304986 A1, the entire contents of which are incorporated herein by reference, adding a magnet(s) to the impeller(s), and/or configuring the motor as an axial gap motor, for example as disclosed in WO 2007/134405 A1, the entire contents of which are incorporated herein by reference.

(45) It should also be appreciated that other flow generator and blower assemblies may be used in the sample embodiments discussed herein. For example, the flow generator and blower assemblies disclosed in U.S. application Ser. Nos. 29/274,504, 29/274,505, and 29/274,506, each filed Apr. 27, 2007, and WO 2007/048206 A1, the entire contents of each being incorporated herein by reference, may be used. As another example, the flow generator and blower assemblies disclosed in U.S. application Ser. Nos. 29/274,504, 29/274,505, and 29/274,506, filed Apr. 27, 2007, 2006, and WO 2007/048205 A1, the entire contents of which are incorporated herein by reference, may be used.

Respiratory Apparatus Third Embodiment

(46) Referring to FIG. 16, a respiratory apparatus according to another sample embodiment comprises a flow generator 4 provided in a flow generator housing 6 configured to engage the head of the patient, for example the crown of the patient's head. The flow generator 4 is configured to deliver a flow of pressurized breathable gas to delivery conduits 8 which are configured to extend from the flow generator along the sides of the face of the patient to a patient interface 10. The patient interface may include nasal pillows or prongs, a nasal mask, a full face mask, or cannulae.

(47) Power is provided to the flow generator 4 by a power supply and controller 66 that is connected to the flow generator 4 by an electrical connector 68, for example a cable. The power supply/controller 66 may be configured to be docked in a battery charger, or may include an attachment that allows for charging of the power supply and controller from a voltage source, for example a common household 120 volt AC socket, or a 12 volt car battery charging outlet. The remaining configuration and features of the flow generator and blower assembly, respectively, may correspond to those discussed and shown with respect to the preceding and following embodiments.

Respiratory Apparatus Fourth Embodiment

(48) Referring to FIG. 17, a respiratory apparatus according to another sample embodiment may comprise a headgear 80 that may take the form of, for example, a skull cap. A pair of ear covering portions 82 may be provided as well as a head covering portion 88. A head circling band 90 may be provided between the ear covering portions 82 and the head covering portion 88. A pair of straps, e.g. chin straps, 84, 86 may be provided to the ear covering portions 82 to secure the headgear 80 to the patient.

(49) The flow generator may be provided in the headgear 80, for example in the head covering portion 88. The power supply (e.g. the battery, or batteries, including the flexible cells) and the control electronics (e.g. the voltage regulator and/or the motor controller) may also be provided in the headgear 80, for example in the head covering portion 88 or the ear covering portion(s) 82. The flow generator, the power supply and the control electronics may be encased in foam or other cushioning material to improve the comfort of the headgear. The battery cells may be distributed about the headgear 80 to spread the weight of the power supply throughout the headgear to improve comfort, reduce, or minimize the height of the apparatus, and increase, or maximize, the stability of the apparatus.

Respiratory Apparatus Fifth Embodiment

(50) Referring to FIGS. 18-20, a respiratory apparatus according to another sample embodiment comprises a flow generator 4 comprising a flow generator housing or casing 6. The flow generator 4 may include a blower assembly as previously described. The flow generator housing 6 comprises slots 70 configured to receive a band or strap 72 as shown in FIG. 18. The band or strap 72 may be configured to encircle the chest or arm of the patient to support the flow generator 4 at a position spaced from the head of the patient. A delivery tube or conduit 74 is configured to be connected to the flow generator 4 at a first end and configured to be connected to a patient interface 10 at a second end. The delivery tube or conduit 74 may be a retractable tube or conduit that is flexible and extensible to accommodate movement of the patient's head, and thus movement of the patient interface 10. Such a retractable tube is disclosed in U.S. application Ser. No. 12/211,896, filed Sep. 17, 2008, the entire content being incorporated herein by reference. The patient interface may be held in contact with the face of the patient by a headgear system 76.

(51) As shown in FIG. 19, the band, or strap, 92 may be configured to be integrally formed with the flow generator casing 6. Alternatively, the band or strap may be separately formed and passed through the slots 70 in the flow generator casing 6. The respiratory apparatus can be segmented into the respective elements. For example, the power supply (e.g. battery cells or pack) and the control electronics (e.g. the voltage regulator and/or motor controller) may be located to the left and/or right of the flow generator casing 6 and connected by a flexible joint, such as a cable. This permits a more custom fit to the patient.

(52) As shown in FIGS. 19 and 20, the blower assembly housing may differ from the housing disclosed in FIGS. 4-16 in that the blower assembly housing may include a single outlet tangential to the blower assembly inlet. It should be appreciated, however, that the sample embodiment shown in FIGS. 18-20 may be provided with a pair of outlets, and a pair of delivery tubes or conduits which may deliver the flow of pressurized breathable gas to a patient interface having two inlets, for example an inlet on each side of the patient interface. Such a patient interface is disclosed, for example, in WO 2005/063328 A1, assigned to ResMed Ltd.

(53) The flow generator housing 6 may be configured to support the blower assembly 22, the power source 20, e.g. the battery or battery pack, and control circuitry for operation of the electric motor of the blower assembly.

(54) Referring to FIG. 21, a variation of the sample embodiment of FIGS. 18-20 may include a concentric air inlet tube 78 surrounding the air delivery tube 74. If the flow generator is worn beneath the patient's bed clothes, e.g. pyjamas, the concentric air inlet tube may be placed outside the patient's bed clothes to draw fresh air into the flow generator housing.

(55) In the sample embodiments described above, the flow generator may be turned on and off using a switch. It should also be appreciated that the flow generator may be turned on using ResMed's SMART START® control.

(56) Respiratory Apparatus Sound Levels

(57) The sample embodiments of the respiratory apparatus disclosed herein may be configured so that the noise level is sufficiently low to allow patients to sleep. In general, typical flow generators are often configured such that the sound power emitted is about 25 dB based on testing 1 meter away at the front of the device. However, the sample embodiments of the respiratory apparatus disclosed herein are configured to be placed on the user's person, e.g. on the head, an arm, the chest. This proximity of the flow generator to the user may result in an increased sound level experienced by the user, for example by about 10 dB(A). In addition, the sample embodiments disclosed herein may include less insulation around the blower assembly of the flow generator, which may further increase the sound level experienced by the user, for example by about another 10 dB(A). For comparison, a flow generator such as that disclosed in U.S. Patent Application Publication 2008/0304986 A1, the entire contents of which are incorporated herein by reference, comprising no insulation emits about 52 dB(A) sound power when running at 10 cm H.sub.2O air pressure.

(58) The sample embodiments of the respiratory apparatus disclosed herein may comprise insulating material within the headgear, mask, blower assembly, and/or flow generator casing, and/or a muffler, to reduce the sound power emitted. For example, the headgear may be configured to reduce the sound power emitted by about 5-10 dB(A). The sample embodiments of the respiratory apparatus disclosed herein may emit a sound power of between about 10-100 dB(A), for example about 10-65 dB(A), as another example about 10-50 dB(A), as a further example about 20-40 dB(A), and as an even further example less than about 25 dB(A), when the respiratory apparatus is providing a flow at about 10 cm H.sub.2O.

(59) In this specification, the word “comprising” is to be understood in its “open” sense, that is, in the sense of “including”, and thus not limited to its “closed” sense, that is the sense of “consisting only of.” A corresponding meaning is to be attributed to the corresponding words “comprise”, “comprised” and “comprises” where they appear.

(60) The term “air” will be taken to include breathable gases, for example air with supplemental oxygen. It is also acknowledged that the blowers described herein may be designed to pump fluids other than air.

(61) While the invention has been described in connection with what are presently considered to be the most practical and preferred embodiments, it is to be understood that the invention is not to be limited to the disclosed embodiments, but on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the invention. Also, the various embodiments described above may be implemented in conjunction with other embodiments, e.g., aspects of one embodiment may be combined with aspects of another embodiment to realize yet other embodiments. Further, each independent feature or component of any given assembly may constitute an additional embodiment.

(62) Furthermore, each individual component of any given assembly, one or more portions of an individual component of any given assembly, and various combinations of components from one or more embodiments may include one or more ornamental design features. In addition, while the invention has particular application to patients who suffer from OSA, it is to be appreciated that patients who suffer from other illnesses (e.g., congestive heart failure, diabetes, morbid obesity, stroke, barriatric surgery, etc.) can derive benefit from the above teachings. Moreover, the above teachings have applicability with patients and non-patients alike in non-medical applications.