U.S. patent application number 11/988870 was filed with the patent office on 2011-11-24 for humidifier and/or flow generator for cpap.
This patent application is currently assigned to ResMed Limited. Invention is credited to Dan Kao, Perry Lithgow, Ian Smith, John Snow.
Application Number | 20110283999 11/988870 |
Document ID | / |
Family ID | 37757242 |
Filed Date | 2011-11-24 |
United States Patent
Application |
20110283999 |
Kind Code |
A2 |
Smith; Ian ; et al. |
November 24, 2011 |
HUMIDIFIER AND/OR FLOW GENERATOR FOR CPAP
Abstract
A CPAP device includes a humidifier including humidifier tub
having a heat conducting base plate; and a cradle to support the
humidifier tub in an operative position. The cradle may also
support a flow generator in operative relation to the humidifier
tub. The cradle includes a heater plate in communication with the
heat conducting base plate of the humidifier tub in use. The cradle
further includes a retaining mechanism to retain the humidifier tub
in the cradle, the retaining mechanism being structured to force
the base plate into engagement with the heater plate. The
humidifier and/or flow generator may include various features to
manage inadvertent back-spill of water from the humidifier to the
flow generator.
Inventors: |
Smith; Ian; (Bella Vista,
New South Wales, AU) ; Snow; John; (Killarney
Heights, New South Wales, AU) ; Lithgow; Perry;
(Moruya, New South Wales, AU) ; Kao; Dan;
(Northbridge, New South Wales, AU) |
Assignee: |
ResMed Limited
1 Elizabeth Macarthur Drive
Bella Vista, New South Wales
AU
2153
|
Prior
Publication: |
|
Document Identifier |
Publication Date |
|
US 20090194106 A1 |
August 6, 2009 |
|
|
Family ID: |
37757242 |
Appl. No.: |
11/988870 |
Filed: |
August 15, 2006 |
PCT Filed: |
August 15, 2006 |
PCT NO: |
PCT/AU2006/001170 |
371 Date: |
February 27, 2009 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
60/707,948 |
Aug 15, 2005 |
|
|
|
Current U.S.
Class: |
128/203.16 |
Current CPC
Class: |
A61M 16/0075 20130101;
A61M 2205/21 20130101; A61M 2205/3334 20130101; B01D 47/02
20130101; A61M 16/08 20130101; A61M 16/109 20140204; A61M 16/0616
20140204; A61M 16/0666 20130101; A61M 16/16 20130101; A61M 16/1075
20130101; A61M 16/0816 20130101; A61M 2209/086 20130101; A61M
2205/02 20130101; A61M 16/10 20130101; A61M 2205/42 20130101; A61M
16/0057 20130101; A61M 16/0066 20130101; A61M 16/0875 20130101 |
Class at
Publication: |
128/203.16 |
International
Class: |
A61M 16/16 20060101
A61M016/16 |
Claims
1. A CPAP device comprising: a humidifier tub including a heat
conducting base plate; and a cradle to support the humidifier tub
in an operative position, the cradle including a fixed heater plate
in communication with the heat conducting base plate of the
humidifier tub in use, the cradle further including a retaining
mechanism to retain the humidifier tub in the cradle, the retaining
mechanism structured to force the base plate into engagement with
the heater plate wherein the retaining mechanism includes a biasing
structure that forces the base plate in a direction towards the
heater plate, the biasing structure configured to allow
disengagement during installation of the humidifier tub with the
cradle and reengagement after installation of the humidifier
tub.
2. The CPAP device according to claim 1, wherein the biasing
structure includes at least one spring that forces the base plate
into engagement with the heater plate.
3. The CPAP device according to claim 1, wherein the retaining
mechanism includes a securing catch that lifts up and down to
enable release or insertion of the humidifier tub.
4. The CPAP device according to claim 1, wherein the retaining
mechanism includes a docking portion that is slidable between a
humidifier locking position and a humidifier unlocking
position.
5. The CPAP device according to claim 1, wherein the retaining
mechanism includes a spring-biased clamping edge that clamps the
humidifier tub to the cradle.
6. The CPAP device according to claim 1, wherein the retaining
mechanism includes a pivotable front guard and a pivotable
humidifier retaining portion, the front guard being pivotable in a
first direction to release the humidifier retaining portion for
receiving the humidifier tub and pivotable in an opposing second
direction to secure the humidifier retaining portion together with
the humidifier tub in the operative position.
7. The CPAP device according to claim 1, wherein the retaining
mechanism includes a front guard that enables release or insertion
of the humidifier and at least two pressure pads that maintain
engagement between the base plate and the heater plate.
8. The CPAP device according to claim 1, further comprising a flow
generator provided to the cradle and in communication with the
humidifier tub.
9. The CPAP device according to claim 8, wherein the flow generator
includes a motor having a motor outlet, a muffler chamber having an
inlet coupled to the motor outlet and an muffler outlet in
communication with a flow generator outlet.
10. The CPAP device according to claim 9, wherein an axis of the
motor outlet is offset from an axis of the muffler outlet and/or
the flow generator outlet.
11. The CPAP device according to claim 9, wherein the muffler
chamber is structured to store a predetermined amount of water that
may be inadvertently introduced into the flow generator outlet from
the humidifier.
12. The CPAP device according to claim 9, wherein said muffler
chamber includes an upper part conduit portion and a lower storage
portion integrally formed with the part conduit portion.
13. The CPAP device according to claim 9, wherein the predetermined
amount of water is about 100 ml.
14. (canceled)
15. The CPAP device according to claim 1, wherein the cradle and/or
humidifier tub includes alignment structure such that the tub can
only be oriented in one way relative to the cradle.
16. The CPAP device according to claim 1, further comprising a
locking structure to secure the humidifier tub relative to the
cradle during use.
17. (canceled)
18. The CPAP device according to claim 1, wherein the heater plate
includes a ceramic heating element.
19. A method for retaining a humidifier tub to a cradle,
comprising: providing a cradle including a retaining mechanism, the
retaining mechanism including a biasing structure; moving the
retaining mechanism to a first position that enables insertion of
the humidifier and disables the biasing structure; providing the
humidifier tub to the cradle; and moving the retaining mechanism to
a second position that secures the humidifier tub in an operative
position and enables the biasing structure to force a heat
conducting base plate of the humidifier tub into engagement with a
fixed heater plate of the cradle.
20. A CPAP device comprising a flow generator including a flow
generator outlet, a motor having a motor outlet, a muffler chamber
having an inlet coupled to the motor outlet and a muffler chamber
outlet in communication with a flow generator outlet, wherein an
axis of the motor outlet is offset from an axis of the muffler
chamber outlet and/or the flow generator outlet.
21. The CPAP device according to claim 20, wherein the muffler
chamber is structured to store a predetermined amount of water that
may be inadvertently introduced into the flow generator outlet from
the humidifier.
22. The CPAP device according to claim 21, wherein the
predetermined amount of water is about 100 ml.
23. A CPAP device comprising a flow generator including a flow
generator outlet, a motor having a motor outlet, a muffler chamber
having an inlet coupled to the motor outlet and a muffler chamber
outlet in communication with a flow generator outlet, wherein said
muffler chamber includes an upper part conduit portion and a lower
storage portion integrally formed with the part conduit
portion.
24. The CPAP device according to claim 23, wherein the upper part
conduit portion includes inlet and outlet fittings to be coupled
with the motor outlet and the flow generator outlet,
respectively.
25. The CPAP device according to claim 23, wherein an axis of the
motor outlet is aligned with an axis of the muffler chamber outlet
and/or the flow generator outlet.
26. The CPAP device according to claim 23, wherein the lower
storage portion is structured to store a predetermined amount of
water that may be inadvertently introduced into the flow generator
outlet from the humidifier.
27. The CPAP device according to claim 26, wherein the
predetermined amount of water is about 100 ml.
28. A humidifier assembly adapted to be coupled to a flow
generator, the humidifier assembly comprising: a cradle having a
tub support surface and a heater plate provided to the tub support
surface; a humidifier supported by the cradle and including a tub
having an inlet positioned on a rear wall of the tub and an outlet
located on a top lid of the tub, the inlet being adapted to be in
fluid communication with an output from the flow generator in use,
the outlet of the tub being adapted to be in fluid communication
with an air delivery conduit in use; the humidifier including a
heat conducting base plate provided to a bottom portion of the tub
and adapted to be in thermal contact with the heater plate of the
cradle when the tub is positioned within the cradle by sliding the
tub from front to back relative to the cradle, the tub and base
plate defining a chamber that is adapted to receive a volume of
water, wherein, in use, a supply of pressurized air from the flow
generator enters the inlet of the tub and collects moisture through
contact with water within the tub before continuing on to the
outlet of the tub; a connector positioned adjacent the inlet of the
tub, the connector including an attaching portion and a flexible
sealing portion formed in one piece with the attaching portion, the
flexible sealing portion defining a face seal of silicone, the face
seal comprising an aperture that is adjacent to or abuts a flat
surface surrounding the inlet of the tub when the tub is properly
docked on the cradle, wherein the flexible sealing portion has a
diameter that is greater than a diameter of the attaching
portion.
29. A humidifier assembly according to claim 28, wherein the face
seal comprises a conforming, bellows-type seal.
30. A humidifier assembly according to claim 29, wherein the
bellows-type seal includes an internal channel positioned adjacent
the inlet of the tub in use.
31. A humidifier assembly according to claim 30, wherein the
attaching portion includes a sealing element.
32. A humidifier assembly according to claim 31, wherein the
flexible sealing portion is constructed such that it does not have
any split lines.
33. A humidifier assembly according to claim 31, wherein the
aperture on the face seal is larger than an inlet aperture of the
inlet of the tub.
34. A humidifier assembly according to claim 33, wherein the face
seal is conformable along an axis of the inlet of the tub.
35. A humidifier assembly according to claim 34, wherein the face
seal is flexible, upwards, downwards, and/or sideways, angularly,
pivotally, and/or rotationally to accommodate misalignment and/or
manufacturing tolerances.
36. A humidifier assembly according to claim 34, wherein the face
seal is conformable and flexible within a predetermined range.
37. A humidifier assembly according to claim 36, wherein the face
seal is axially and/or laterally flexible within a range of about
1-5 mm.
38. A humidifier assembly according to claim 37, wherein the face
seal is configured to form a seal with the inlet of the tub even if
the axis of the connector is not aligned with the axis of the
inlet.
39. A humidifier assembly according to claim 38, wherein the tub
includes a baffle adjacent the inlet, the baffle including a curved
surface to promote circulation and water pickup.
40. A humidifier assembly according to claim 39, wherein the base
plate comprises aluminum.
41. A humidifier assembly according to claim 28, wherein a maximum
volume of water is several hundred milliliters.
42. A humidifier assembly according to claim 40, wherein the
attaching portion is attached to a structure that receives a flow
of breathable gas from the flow generator.
43. A humidifier assembly according to claim 42, wherein the face
seal comprises a pressure-activated seal.
44. A humidifier assembly according to claim 43, wherein the
attaching portion of the connector is removably attached to the
structure that receives the flow of breathable gas from the flow
generator and the flexible sealing portion protrudes therefrom, the
inlet of the tub being positioned adjacent to or abutting the face
seal such that when pressurized air flows out through the outlet of
the flow generator, the face seal fills with air and establishes a
pressurized face seal with the inlet of the humidifier tub.
45. A humidifier assembly according to claim 44, wherein the face
seal is spaced from the inlet of the tub, in an initial position,
and, as pressurized air flows into the tub, the face seal fills
with air and expands into engagement with an axially facing surface
of the inlet of the tub.
46. A humidifier assembly according to claim 44, wherein the face
seal of the flexible sealing portion has approximately 2 mm to 3 mm
interference from a nominal contact point to ensure sufficient
contact when the inlet of the tub and the connector make contact on
each other.
47. A CPAP device including: a flow generator to generate
pressurized gas in the range of 4-28 cm H.sub.2O; and the
humidifier assembly of claim 28.
48. A CPAP device according to claim 47, further comprising a
structure in communication with the flow generator and the
humidifier assembly, the attaching portion of the connector being
connected to the structure.
49. A CPAP device according to claim 48, wherein the cradle is
structured to support the humidifier tub in an operative position
with respect to the flow generator.
50. A CPAP device according to claim 49, wherein the cradle is
structured to push the humidifier tub downwards onto the heater
plate.
51. A CPAP device according to claim 50, further comprising a
spring to bias the heater plate and the base plate into firm
thermal contact with one another.
52. A CPAP device according to claim 51, wherein the cradle
includes a securing catch that lifts up and down to enable release
or insertion of the humidifier tub.
53. A CPAP device according to claim 52, wherein the securing catch
is hinged to a main body of the cradle.
54. A CPAP device according to claim 54, wherein the catch includes
a stop positioned in front of the tub when the catch is closed to
retain the tub in place.
55. A CPAP device according to claim 53, wherein the catch is
structured to prevent access to the heater plate when the tub is
inserted, including access to the front of the heat conducting base
plate.
56. A CPAP device according to claim 53, wherein the cradle
includes upstanding side walls to engage sides of the tub upon
sliding insertion of the tub into the cradle when docking.
57. A CPAP device according to claim 56, wherein the side walls
include generally planar surfaces.
58. A CPAP device according to claim 57, wherein gaps between the
sides of the tub and the cradle are dimensioned to be smaller than
the size of a finger.
59. A CPAP device according to claim 53, wherein the catch is
structured to provide a clicking sound when the tub is properly
docked thereby providing audio and/or tactile feedback.
60. A CPAP device comprising: a humidifier tub including a heat
conducting base plate; and a cradle to support the humidifier tub
in an operative position, the cradle including a heater plate in
communication with the heat conducting base plate of the humidifier
tub in use, the cradle further including retaining structure to
retain the humidifier tub in the cradle, wherein the retaining
structure includes a hinged securing catch that lifts up and down
to enable release or insertion of the humidifier tub and lateral
portions to provide downwardly directed force to ensure good
thermal contact between the base plate of the tub and the heater
plate.
61. A CPAP device according to claim 60, wherein the retaining
structure includes at least one spring that forces the base plate
into engagement with the heater plate.
62. A CPAP device according to claim 61, further including a one
piece face seal provided adjacent an inlet of the tub, the face
seal having an attaching end and a flexible, compliant sealing
portion to contact a planar surface of the tub surrounding the
inlet of the tub upon docking the tub relative to the cradle.
63. A CPAP device according to claim 62, further comprising a flow
generator in communication with the humidifier tub.
64. A CPAP device according to claim 63, wherein the flow generator
includes a motor having a motor outlet in communication with a flow
generator outlet.
65. A CPAP device according to claim 64, wherein an axis of the
motor outlet is oriented to be offset with an axis of the flow
generator outlet.
66. A CPAP device according to claim 65, further comprising a
spill-back chamber positioned in front of the inlet of the tub, to
store a predetermined amount of water that may be inadvertently
introduced toward the flow generator outlet from the
humidifier.
67. A CPAP device according to claim 66, wherein the predetermined
amount of water is about 100 ml.
68. A CPAP device according to claim 60, wherein the retaining
structure receives sides of the of the humidifier tub upon initial
insertion of the humidifier tub into the cradle and initially
directs the heat conducting base plate over the heater plate and
directs the heat conducting base plate into contact with the heater
plate upon full insertion of the humidifier tub in the cradle.
69. A CPAP device, comprising: a flow generator to generate
pressurized gas in a range of 4-28 cm H.sub.2O; a humidifier
assembly to humidify the pressurized gas flow, the humidifier
assembly comprising a tub to store liquid and including an inlet to
receive the pressurized gas flow and direct the pressurized gas
flow into contact with the liquid, a heat conducting base plate
provided to a bottom portion of the tub, and an outlet to deliver
the humidified pressurized gas flow, and a cradle to support the
tub in an operative position to receive the pressurized gas flow,
the cradle including a heater plate in contact with the heat
conducting base plate of the humidifier tub in the operative
position, a retaining mechanism to retain the tub in the cradle and
to bring the base plate into engagement with the heater plate, and
a spring to bias the heater plate and the base plate into firm
thermal contact with one another; and a connector including an
inlet to receive the pressurized gas flow from the flow generator,
an outlet to deliver the pressurized gas flow to the inlet of the
tub, and a conforming, bellows-type seal to seal the inlet of the
tub when the tub is in the operative position and a pressurized gas
flow is in the connector.
70. A method according to claim 19, wherein the biasing structure
includes at least one spring.
Description
CROSS-REFERENCE TO PRIORITY APPLICATION
[0001] This application is the U.S. national phase of International
Application No. PCT/AU2006/001170, which designated the U.S. and
claims the benefit to U.S. Provisional Application No. 60/707,948,
filed 15 Aug. 2005, the entire contents of each of which are hereby
incorporated by reference.
FIELD OF THE INVENTION
[0002] The present invention relates to a removable humidifier
and/or flow generator for a Continuous Positive Airway Pressure
(CPAP) device used to treat sleep disordered breathing (SDB)
conditions such as Obstructive Sleep Apnea (OSA).
BACKGROUND OF THE INVENTION
[0003] Domestic treatment of OSA and other SDB is usually done
using a device that provides CPAP, e.g., nasal CPAP. A common
configuration of a treatment system comprises a CPAP device and a
patient interface, e.g., a nasal mask. The nasal mask forms a
sealing interface with the patient's nasal passages in use so that
the supply of air at positive pressure from the CPAP device may be
delivered to the patient's airways. In this way, while the patient
is wearing a nasal mask, their mouth is uncovered.
[0004] In some situations, patients "mouth breath" during sleep.
When this happens while wearing only a nasal mask, air can pass in
the mask and straight out the patient's mouth. This can lead to
drying of the patient's airway and patient discomfort. This patient
discomfort can to some extent be alleviated by the use of a
humidifier placed between the CPAP device and the patient
interface.
[0005] Many humidifiers are available, although the most convenient
form is one that is either integrated with or configured to be
coupled to the relevant CPAP device. While passive humidifiers can
provide some relief, generally a heated humidifier is required to
provide sufficient moisture to the air so that patients will be
comfortable. Humidifiers typically comprise a water tub having a
capacity of several hundred milliliters, a heating element, a
control to enable the level of humidification to be varied, an air
inlet to receive air from the blower, and an air outlet adapted to
be connected to an air delivery conduit so that the humidified
pressurized air may be passed to the patient interface. Usually,
the water tub is removable from the system so that it can be
refilled when necessary.
[0006] In making a humidification tub removable, there are two
problems that need to be overcome. Firstly, there is a need for an
air seal between the air outlet of the flow generator and the air
inlet of the humidifier tub. An air seal is important to reduce air
leaks that may result in an increased pressure drop between the air
pressure generated by the flow generator and the air pressure
delivered to the patient at the patient interface. Secondly, for
efficient humidification, there must be adequate thermal contact
between the humidification tub and the heating element.
[0007] Commonly, humidifier tubs are attached either directly to a
humidifier control base or to a system base or cradle that
facilitates the correct assembly of the flow generator with the
humidifier. Generally, the humidifier control base or the system
base or cradle comprises a heating plate that contacts the base of
the humidifier tub to facilitate heating of the water within the
humidifier tub. Commonly, these base systems comprise a spring
loaded heater plate on to which the humidifier tub is attached. The
spring loaded heater plate ensures good thermal contact with the
base of the humidifier tub. For example, the Fisher & Paykel
HC200 system and the Respironics RemStar heated humidifier have
spring loaded heater plates. However, such spring loaded heater
plates can provide a friction force against insertion of the
humidifier tub, which may make installation of the humidifier tub
difficult for some users, especially older or frail users.
SUMMARY OF THE INVENTION
[0008] One aspect of the invention relates to a seal between the
humidifier inlet and flow generator outlet.
[0009] Another aspect of the invention relates to a method and
apparatus for retaining a humidifier tub for use in a CPAP device,
e.g., nasal CPAP device.
[0010] Another aspect of the invention relates to a method and
apparatus for providing good thermal contact between the humidifier
tub and a heating element.
[0011] Another aspect of the invention relates to management of the
inadvertent introduction of water into the flow generator, e.g., by
tipping or overfilling the humidifier.
[0012] Yet another aspect of the invention relates to a CPAP device
or humidifier including a humidifier tub including a heat
conducting base plate and a cradle to support the humidifier tub in
an operative position. The cradle includes a heater plate in
communication with the heat conducting base plate of the humidifier
tub in use. The cradle further includes a retaining mechanism to
retain the humidifier tub in the cradle. The retaining mechanism is
structured to force the base plate into engagement with the heater
plate.
[0013] Another aspect of the present invention relates to a CPAP
device including a cradle having a fixed heating plate; and a
humidifier tub having a heat conducting base, the base being is
forcibly coupled with the fixed heating plate of the cradle upon
assembly of the cradle and the humidifier tub.
[0014] Still another aspect of the invention relates to a method
for retaining a humidifier tub to a cradle, comprising providing a
cradle including a retaining mechanism; moving the retaining
mechanism to a first position that enables insertion of the
humidifier tub; providing the humidifier tub to the cradle; moving
the retaining mechanism to a second position that secures the
humidifier tub in an operative position; and forcing a heat
conducting base plate of the humidifier tub into engagement with a
heater plate of the cradle.
[0015] Another aspect of the invention relates to a CPAP device
comprising a flow generator including a flow generator outlet, a
motor having a motor outlet, a muffler chamber having an inlet
coupled to the motor outlet and a muffler chamber outlet in
communication with a flow generator outlet, wherein an axis of the
motor outlet is offset from an axis of the muffler chamber outlet
and/or the flow generator outlet.
[0016] Still another aspect of the invention relates to a CPAP
device comprising a flow generator including a flow generator
outlet, a motor having a motor outlet, a muffler chamber having an
inlet coupled to the motor outlet and a muffler chamber outlet in
communication with a flow generator outlet, wherein said muffler
chamber includes an upper part conduit portion and a lower storage
portion integrally formed with the part conduit portion.
[0017] These and other aspects, features, and advantages of this
invention will become apparent from the following detailed
description when taken in conjunction with the accompanying
drawings, which are a part of this disclosure and which illustrate,
by way of example, principles of this invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] The accompanying drawings facilitate an understanding of the
various embodiments of this invention. In such drawings:
[0019] FIG. 1 is a perspective view of a CPAP device according to
an embodiment of the invention;
[0020] FIG. 2 is a top view of the CPAP device shown in FIG. 1;
[0021] FIG. 3 is a side view of the CPAP device shown in FIG.
1;
[0022] FIG. 4 is an end view of the CPAP device shown in FIG.
1;
[0023] FIG. 5 illustrates a blower with a seal/connector according
to an embodiment of the present invention;
[0024] FIG. 6 illustrates the blower and seal/connector of FIG. 5
in an exploded position;
[0025] FIG. 7 is a cross section along section 7-7 of FIG. 5;
[0026] FIG. 8A is a cross-sectional view illustrating a
seal/connector according to another embodiment of the present
invention;
[0027] FIGS. 8B-8C illustrate a seal/connector according to an
embodiment of the present invention in use;
[0028] FIGS. 9-12 illustrate a cradle according to an embodiment of
the present invention using a catch to secure the humidifier
tub;
[0029] FIG. 13 illustrates a cradle according to another embodiment
of the present invention using a sliding docking portion to secure
the humidifier tub;
[0030] FIGS. 14A, 14B, and 15 illustrate a cradle according to
another embodiment of the present invention using a pivoting
docking portion to secure the humidifier tub;
[0031] FIG. 16 illustrates a cradle according to another embodiment
of the present invention using a spring-biased clamping edge to
secure the humidifier tub;
[0032] FIGS. 17-22 illustrate a cradle according to another
embodiment of the present invention using a pivotable front guard
and a pivotable humidifier retaining portion;
[0033] FIGS. 23-25 illustrate a cradle according to another
embodiment of the present invention using a front guard and at
least two pressure pads;
[0034] FIG. 26 illustrates a humidifier tub secured to the cradle
shown in FIGS. 23-25, the humidifier tub engaged with the
seal/connector shown in FIGS. 5-7;
[0035] FIG. 27 is a cross-sectional view through the humidifier tub
and cradle shown in FIG. 26;
[0036] FIG. 28 is an exploded view of a flow generator according to
an embodiment of the present invention;
[0037] FIG. 29 is a schematic drawing illustrating the general
architecture of a portion of a flow generator according to an
embodiment of the present invention; and
[0038] FIG. 30 is a schematic exploded view of a portion of a flow
generator according to an embodiment of the present invention.
DETAILED DESCRIPTION OF ILLUSTRATED EMBODIMENTS
1. CPAP Device
[0039] FIGS. 1-4 illustrate a CPAP device 10 according to an
embodiment of the present invention. As illustrated, the CPAP
device 10 includes a flow generator 20 and a humidifier 30 adapted
to be coupled to the flow generator 20.
[0040] The humidifier may be connected to the flow generator using
loop-back power and communication cables between the humidifier and
the flow generator. In an alternative, the humidifier and the flow
generator may communicate using a fiber optic or infrared
communication system between the flow generator and the humidifier.
This system may detect the presence of the humidifier tub and
provide communication and power between the devices via
transmitters and receivers.
2. Humidifier
[0041] The humidifier 30 includes a humidifier tub 50 having a base
plate 52 sealed to the bottom of the tub 50 and a heater element
that may be formed as part of a cradle unit 40 (see FIG. 9). The
heater element may also be formed as an integral part of the base
plate or otherwise separate from the cradle. The tub 50 includes an
inlet 54 adapted to be in fluid communication with (i.e. not
necessarily directly) the outlet 24 of the flow generator 20, and
an outlet 56 adapted to be connected to an air delivery conduit.
The air delivery conduit includes one end coupled to the outlet 56
of the tub 50 and an opposite end coupled to a patient interface.
The patient interface comfortably engages the patient's face and
provides a seal. The patient interface may have any suitable
configuration as is known in the art, e.g., full-face mask, nasal
mask, oro-nasal mask, mouth mask, nasal prongs, etc.
[0042] The tub 50 and base plate 52 define a chamber that is
adapted to receive a volume of water, e.g., several hundred
milliliters. The inlet 54 and the outlet 56 are both in
communication with the chamber. In use, a supply of pressurized air
from the flow generator 20 enters the inlet 54 of the tub 50 and
collects moisture through contact with the water within the tub 50
before continuing on to the outlet 56 and to the patient via the
air delivery conduit.
[0043] As best shown in FIG. 2, the tub 50 may include a curved
baffle 15 adjacent the outlet end of the inlet 54 to smoothly
change the direction of the air flow by gently guiding the air flow
around the tub 50 while limiting the loss of pressure. Also, the
base plate 52 may be in the form of a heat conducting base plate.
Specifically, the base plate 52 may be formed of a heat conducting
material, e.g., aluminum sheet.
[0044] In an embodiment, the humidifier 30 and tub 50 may be
structured such as the humidifier and tub described in U.S. Patent
Application No. 60/707,949, entitled "Humidifier Tub For CPAP
Device", filed Aug. 15, 2005, the contents of which are
incorporated in its entirety by reference herein. Also, in an
embodiment, the flow generator 20 may be structured and controlled
such as the flow generator described in U.S. Patent Application No.
60/707,951, entitled "Low Cost CPAP Flow Generator and Humidifier
Assembly", filed Aug. 15, 2005, the contents of which are
incorporated in its entirety by reference herein.
3. Seal Between Humidifier and Flow Generator
[0045] FIGS. 5-7 illustrates a connector 60 according to an
embodiment of the present invention. The connector 60 interconnects
the outlet 24 of the flow generator 20 and the inlet 54 of the tub
50. Moreover, the connector 60 provides a pressure-activated or
self-energizing face seal that provides a seal between the flow
generator 20 and the tub 50. The seal accommodates misalignment and
manufacturing tolerances as described below.
[0046] As illustrated, the connector 60 provides a channel 62 (FIG.
7) to deliver pressurized air from the flow generator 20 to the
humidifier tub 50. In the illustrated embodiment, the connector 60
is removably attached to the flow generator 20 and is structured to
sealingly engage with the inlet 54 of the tub 50.
[0047] As best shown in FIG. 7, the connector 60 includes two
components that are coupled to one another. Specifically, the
connector 60 includes a firm frame attaching portion 64 and a
flexible sealing portion 66. The firm frame attaching portion 64 is
preferably constructed of a plastic material and includes an
attachment structure that enables secure attachment to the outlet
24 of the flow generator 20. For example, the attachment structure
may be in the form of a snap-fit clip that includes one or more
protrusions 68 adapted to engage within a corresponding groove 70
provided in the outlet 24 with a snap fit, as shown in FIG. 7.
However, the attachment structure may have other suitable
configurations.
[0048] The flexible sealing portion 66 comprises a bellows-type
conforming face seal 72 preferably made from silicone or other
similar material that does not provide problems with creep in use.
The bellows-type conforming face seal 72 comprises an aperture 74
that is adapted to abut the inlet 54 of the humidifier tub 50. The
flexible sealing portion 66 further includes an internal sealing
element 76, e.g., wiper seal, that independently seals to the
outlet 24 of the flow generator 20 to prevent air leakage through
the connection between the flow generator 20 and the humidifier 30.
Any means of providing a seal between the flow generator 20 and
humidifier 30 is encompassed within the scope of the invention. For
example, the internal sealing element 76 may be in the form of a
compression sealing ridge or a wiper seal. The flexible sealing
portion 66 is constructed such that it preferably does not have any
split lines (from the tooling) on the outer sealing face that may
interfere with obtaining a satisfactory pressure seal.
[0049] In addition, the flexible sealing portion 66 includes an
interlocking structure that is structured to interlockingly engage
a complementary interlocking structure provided on the firm frame
attaching portion 64. In the illustrated embodiment, the sealing
portion 66 includes a groove 78 that interlocks with a protrusion
80 provided on the frame attaching portion 64. This arrangement
interlocks the sealing portion 66 to the frame attaching portion
64. However, the sealing portion 66 may be coupled to the frame
attaching portion 64 in other suitable manners.
[0050] Alternatively, the entire connector 60 may be made of
silicone or a silicone-like material with differing rigidity
characteristics for the firm frame attaching portion 64 and the
flexible sealing portion 66. For example, as shown in FIG. 8A, the
connector 60 may have a one-piece construction and the frame
attaching portion 64 may have a cylindrical structure adapted to
sealingly engage the outlet 24 of the flow generator 20.
[0051] Preferably, the connector 60 has a round shape to provide
minimal out-of-mold distortion. The face seal 72 of the flexible
sealing portion 66 has approximately 2 mm to 3 mm interference from
the nominal contact point to ensure sufficient contact when the
connector 60 is pushed against the inlet 54 of the humidifier tub
50. The aperture 74 on the sealing face 72 may be larger than the
inlet 54 of the tub 50 in order to accommodate the various
misalignment and manufacturing tolerances of the connector 60 to
outlet 24 of the flow generator 20, to ensure sufficient passage of
air flow through the connector 60.
[0052] Advantageously, the face seal 72 provides for tolerance in
movement in all directions while aligning the humidifier tub 50 and
the flow generator 20. For example, the face seal 72 is flexible
axially (forwards and backwards), laterally (upwards, downwards,
and/or sideways), angularly, pivotally, and/or rotationally.
Preferably, the face seal is flexible in all directions, although
it may be more flexible in some but more rigid in others.
[0053] The face seal 72 may be flexible within a predetermined
range. For example, the face seal 72 may be axially and/or
laterally flexible within a range of about 1-5 mm, preferably about
2-3 mm. However, the face seal 72 may be axially and/or laterally
flexible less than 1 mm or greater than 5 mm. Also, the face seal
72 may be angularly, pivotally, and/or rotationally flexible within
a range of about 1-10.degree., preferably about 3-6.degree. or
about 5.degree.. However, the face seal 72 may be angularly,
pivotally, and/or rotationally flexible less than 1.degree. or
greater than 10.degree..
[0054] In use, the firm frame attaching portion 64 of the connector
60 is securely attached to the outlet 24 of the flow generator 20
and the bellows-type conforming face seal 72 on the flexible
sealing portion 66 protrudes therefrom. The air inlet 54 of the
humidifier tub 50 is positioned adjacent to or abutting the face
seal 72. When pressurized air flows out through the outlet 24 of
the flow generator 20, the face seal 72 fills with air and
establishes a pressurized face seal with the inlet 54 of the
humidifier tub 50.
[0055] FIGS. 8B and 8C illustrate an embodiment of the connector 60
forming a seal with the inlet 54 of a humidifier tub. As shown in
FIG. 8B, the connector 60 is positioned adjacent the inlet 54 such
that the bellows-type conforming face seal 72 is spaced from the
inlet 54. As pressurized air flows out through the outlet of the
flow generator (as indicated by the arrow), the face seal 72 fills
with air and expands into engagement with the axial end or axially
facing surface of the inlet 54 as shown in FIG. 8C. That is, the
face seal 72 balloons outwardly to form a cylindrical face seal
with the inlet 54.
[0056] The bellows-type conforming face seal 72 provides a flexible
bellows or gusset that allows the face seal 72 to self align with
the inlet 54. That is, the flexibility and freedom of movement of
the face seal 72 (e.g., in all directions within a predetermined
range) allows the face seal 72 to form a seal with the inlet 54
even if they are misaligned. Specifically, the face seal 72 can
still form a seal with the inlet 54 even if the axis of the
connector 60 is not aligned with the axis of the inlet 54. This
arrangement accommodates the various misalignments that may occur
between the connector 60 and the inlet 54.
[0057] Although the connector 60 has been described as being
attached to the outlet 24 of the flow generator 20, in an
alternative embodiment the connector 60 may be attached to the
inlet 54 of the humidifier tub 50 and the flexible sealing portion
66 may abut the outlet 24 of the flow generator 20. In a further
embodiment, the connector 60 may be permanently attached to either
the outlet 24 of the flow generator 20 or the inlet 54 of the
humidifier tub 50. However, the connector 60 is preferably a
separate component that can be easily replaced or removed for
cleaning or sterilization purposes.
4.0 Mechanism for Retaining Humidifier in Cradle
[0058] The CPAP device 10 may include a cradle (e.g., cradle 40 in
FIGS. 9-12) structured to support the humidifier tub 50 in an
operative position with respect to the flow generator 20. The
cradle may include a heater plate that includes a heating element,
e.g., a ceramic heating element. In use, the cradle receives the
humidifier tub 50 so that the heating element is in thermal contact
with the heat conducting base plate 52 (FIG. 3) of the humidifier
tub 50. This arrangement allows water contained within the
humidifier tub 50 to be heated to provide sufficient moisture to
the air so that patients will be comfortable.
[0059] The cradle may provide one or more of the following
functional features for the humidifier tub 50: allow the humidifier
tub 50 to be correctly oriented with respect to the flow generator
20; securely lock the humidifier tub 50 within the cradle such that
it cannot be easily pulled out during use; ensure good thermal
contact between the humidifier tub 50 and the heater plate present
in the cradle; allow easy docking of the humidifier tub 50,
especially for frail, elderly users; and for safety reasons, limit
access to hot areas of the humidifier chamber when heat is being
transferred from the heater plate to the heat conducting base plate
52 of the humidifier tub 50, once the humidifier tub 50 is docked
within the cradle.
[0060] Advantageously, the cradle as described in the various
embodiments herein pushes the humidifier tub downwards onto a fixed
heater plate rather than forcing the heater plate upwards against
the humidifier tub. The fixing of the hot plate in the cradle
improves and simplifies the electrical ensures that the hot plate
is sealed against water entry, which sealing is more difficult if
the hot plate is movably mounted on the cradle. In this type of
arrangement, a spring that forces the humidifier tub into
engagement with the heater plate may be disengaged during
installation of the humidifier tub within the cradle. The
disengagement of the spring reduces friction forces for
installation thus making installation easier and consequently
minimizing friction damage to the heater plate, cradle, and
humidifier tub. After installation of the humidifier tub, the
spring may be reengage to simultaneously secure the humidifier tub
within the cradle and force the base plate of the humidifier tub
against the heater plate to provide good thermal contact between
them.
4.1 Cradle with Securing Catch
[0061] FIGS. 9-12 illustrate a cradle 40 according to an embodiment
of the present invention. As illustrated, the cradle 40 has a
securing catch 44 that lifts up and down to enable release or
insertion of the humidifier tub 50. The securing catch 44 may be
hinged. The lifting up of the securing catch 44 also disables or
releases a spring that pushes the humidifier tub 50 down against
the heater plate 42 (see FIGS. 9 and 10). After insertion of the
humidifier tub 50 along the arms of the catch 44, closure of the
catch 44 re-engages the spring to ensure a good thermal connection
between the humidifier tub 50 and the heater plate (see FIGS. 11
and 12). Releasing the spring (e.g., by lifting the catch)
substantially reduces the forces that have previously acted against
freely inserting or removing the humidifier tub. The catch 44 also
locks the humidifier tub 50 within the cradle 40 such that it
cannot be pulled out during use, e.g., by pulling the air delivery
tube. Specifically, a stop 46 is positioned in front of the
humidifier tub 50 when the catch 44 is closed to lock the
humidifier tub in place. Also, the stop 46 may provide a ridge or
protrusion 43 adapted to lock the catch 44 in a closed position. In
addition, a groove 45 may be provided in the stop 46 to provide a
finger access that facilitates access to the catch 44. The catch 44
also prevents access to the hot heater plate 42 when the humidifier
tub 50 is inserted, especially access to the front of the hot heat
conducting base plate 52. The gaps between the sides of the tub and
the cradle are smaller than the size of a finger (or less) to
prevent accidental burning of the patient. The latch provides a
"clicking" sound when the tub is properly docked thereby providing
audio/tactile feedback to the patient.
4.2 Cradle with Sliding Docking Portion
[0062] FIG. 13 illustrates a cradle 240 according to another
embodiment of the present invention. In this embodiment, the cradle
240 includes a docking portion 244 that is slidable between a
humidifier tub locking position and a humidifier tub unlocking
position (FIG. 13). The slidable mechanism may be similar to that
used in loading a CD or DVD, for example, and may include a spring
to facilitate movement into the humidifier tub unlocking position.
In the humidifier tub unlocking position as shown in FIG. 13, the
docking portion 244 is slidably extended from the cradle 240 to
enable release or insertion of the humidifier tub 50. In the
humidifier tub locking position, the docking portion 244 is
slidably retracted into the cradle 240 to secure the humidifier tub
50 to the cradle 240. In the illustrated embodiment, the docking
portion 244 includes a pin 241 that is adapted to releasably engage
a ramp 243 provided on the cradle 240 to releasably lock the
docking portion in the humidifier tub locking position. However,
the docking portion 244 may be locked in other suitable manners.
Also, a spring-loaded arm 246 may be provided to ensure a good
thermal connection between the humidifier tub 50 and the heater
plate of the cradle 240.
4.3 Cradle with Pivoting Docking Portion
[0063] FIGS. 14A, 14B, and 15 illustrate a cradle 640 according to
another embodiment of the present invention. In this embodiment,
the cradle 640 includes a docking portion 644 that is pivotable
about a hinge 641 between a humidifier tub locking position (FIG.
14A) and a humidifier tub unlocking position (FIG. 14B). The cradle
640 includes a spring 648 that biases the docking portion 644 into
the humidifier tub locking position. In the humidifier tub
unlocking position as shown in FIG. 14B, the docking portion 644 is
pivoted downwardly against bias from the spring 648 to enable
release or insertion of the humidifier tub 50. In the humidifier
tub locking position as shown in FIG. 14A, the docking portion 444
is pivoted upwardly by the spring 648 to secure the humidifier tub
50 to the cradle 640. FIG. 15 is an isolated view of the docking
portion 644 and illustrates retaining members 645 that push down on
the humidifier tub 50 (e.g., the lateral edges).
4.4 Cradle with Spring-Biased Clamping Edge
[0064] FIG. 16 illustrates a cradle 340 according to another
embodiment of the present invention. In this embodiment, a lever or
button (e.g., an actuator button 345) is provided on the cradle 340
that is adapted to release a spring 344 connected with a clamping
edge 346, e.g., a pressure pad. In use, the humidifier tub 50 is
inserted into the cradle 340 and the lever or button is actuated to
release the spring-biased clamping edge 346 which clamps or
frictionally secures the base of the humidifier tub 50 between the
cradle 340 and the clamping edge 346. The clamping edge 346
provides downwardly directed pressure to ensure good thermal
contact between the base of the humidifier tub 50 and the heater
plate.
4.5 Cradle with Pivotable Front Guard and Pivotable Humidifier
Retaining Portion
[0065] FIGS. 17-22 illustrate a cradle 440 according to another
embodiment of the present invention. In this embodiment, the cradle
440 includes two separate hinges 443, 444 that allow independent
movement of a front guard 445 and a humidifier retaining portion
446, respectively. The front guard 445 is pushed or pivoted
downwardly which in turn lifts the humidifier retaining portion 446
so it can pivot in an upward direction (as shown in FIGS. 17, 20,
and 22). This subsequently allows easy insertion of the humidifier
tub 50 into the humidifier retaining portion 446. The humidifier
retaining portion 446 has edges adapted to receive sides of the
humidifier tub 50 therein. Once the humidifier tub 50 is inserted
within the humidifier retaining portion 446, the front guard 445 is
released which allows both the front guard 445 and the humidifier
retaining portion 446 to clasp the humidifier tub 30 and move the
humidifier tub downwardly against the heater plate of the cradle
440 (see FIGS. 18, 19, and 21). Thus, the front guard 445 clamps
the humidifier retaining portion 446 in a closed position. In an
embodiment, a spring provides a bias to force the front guard 445
and the retaining portion 446 into a closed or humidifier retaining
position.
4.6 Cradle with Front Guard and Pressure Pads
[0066] FIGS. 23-27 illustrate a cradle 540 according to yet another
embodiment of the present invention. In this embodiment, the cradle
540 includes a front guard 544 and at least two pressure pads 546.
In the illustrated embodiment, a pressure pad 546 is positioned on
each side of the cradle 540. A spring is attached to each pressure
pad 546. The spring is configured to force the respective pressure
pad 546 in a downward direction toward the bottom of the cradle
540. The front guard 544 includes a spring that forces the front
guard 544 upwardly to protect against access to the cradle 540 and
prevent the humidifier tub 50 from falling out when installed. To
install the humidifier tub 50 to the cradle 540, the front guard
544 is pushed downwardly, thereby allowing the humidifier tub 50 to
access the cradle 540 (see FIG. 24). The bottom edges of the
humidifier tub 50 are then inserted underneath each of the pressure
pads 546 thereby causing the pressure pads 546 to be deflected
upwards against biasing of the springs. This allows the humidifier
tub 50 to slide into the cradle 540 (see FIGS. 25-27). Once the
humidifier tub 50 is located within the cradle 540, the pressure
pads 546 supply the force to maintain the base of the humidifier
tub 50 against the heater plate 542. In an embodiment, movement of
the front guard 544 is coordinated with actuation of the pressure
pads 546. Preferably, the pressure pads 546 are made of smooth
material that provides low friction against the humidifier tub 50
when it is inserted into the cradle 540. FIGS. 26 and 27 illustrate
the humidifier tub 50 located within the cradle 540 and the inlet
54 of the humidifier tub 50 engaged with the connector 60 shown in
FIGS. 5-7.
4.7 Water Damage Mitigation
[0067] In addition to the protection afforded by the tub design,
the flow generator also has one or more water damage mitigating
features.
[0068] System goals: The combined system (the flow generator and
humidifier) should be able to prevent water entry into the flow
generator from scenarios where the unit (flow generator and
humidifier) is tipped up to 60.degree. in any direction (e.g.,
backwards or sidewards). Even though the flow generator and/or
humidifier is ideally designed to prevent water entry into the flow
generator, the flow generator should be capable of handling
spill-back (e.g., about 100 ml) from the humidifier. Spill-back can
occur if water is accidentally introduced directly via the outlet
port. The device should not be damaged, and remain safe, with 100
ml introduced, assuming the device remains in the horizontal
operating position. It should be possible to drain any such water
that has entered the flow generator (contained within the Outlet
Muffler/sump). Furthermore, the flow generator should satisfy the
IPX1 rating requirements, and the requirements of IEC60601.1, to
cope with external spillage of water by user.
[0069] One or more of the above goals can be achieved by
implementation of the illustrative flow generator design shown in
FIG. 28. FIG. 28 shows a flow generator 600 having a top case 605
and a bottom case 610. Top case 605 is provided with a keypad 615
that is operably coupled to a main PCB 620 with SMPS. Bottom case
610 is provided with base rubber feet 625. Arrows 630 schematically
show the approximate path of air as it flows into, through and out
of the flow generator 600. The bottom case 610 includes an inlet
that directs incoming air to a motor chamber 635 that houses a
motor 640. The motor 640 pressurizes the air and directs it to a
sound muffler 645 that provides acoustic noise reduction. From the
muffler 645, the pressurized gas exits via an outlet 650 that is in
communication with an air delivery conduit. Sound insulation
materials 655 may be provided, but these are preferably outside the
air path.
[0070] The ability to cope with water intake at the flow generator
air outlet 650 is achieved in this example by having the muffler
645 act essentially as a water sump/pump, where water cannot reach
the electronics or the motor unless the device is intentionally
tipped over and/or tilted backwards.
[0071] Water that has entered the flow generator 600, and is
contained in the muffler 645, can be drained by tilting the flow
generator forward for water to exit the air delivery port. The
outlet 650 of flow generator 600 is arranged such that when the
device is tipped forward it is the lowest point of the volume where
water is trapped. Otherwise, the water will simply evaporate over
time.
[0072] Other water mitigation features include the following
features, each of which can be used alone or in combination with
one or more of the other features:
[0073] Mounting the blower air inlet downwards, allowing spill back
from the Humidifier to drain out of the blower inlet (into the Fan
Cover) and away from the motor;
[0074] Having a very large volume (essentially the vacant space of
bottom case--much larger than 100 ml) outside of and lower than the
blower, so that water spill back has to completely fill this
chamber before it can reach the motor;
[0075] Placing all electronics at the top of the device well away
from internal water; and/or
[0076] Placing the electrical interfaces (all cable connections
including power) not only high on the device but above the air
inlet opening where spilled water could enter the device.
[0077] For IPX1 and IEC60601.1 tests, sealing should be provided on
the joints between keypad 615 and top case 605. Top case 605
shrouding 606 may also be constructed to form an "awning" over the
power inlet and humidifier communications sockets. The joint
between the top and bottom cases is designed to be noise tight.
[0078] The geometry of the flow generator layout is such that the
sump chamber of the muffler 645 and the flow generator outlet port
650 are not axially aligned with a motor outlet 660. As shown in
FIG. 28, the motor outlet 660 directs the pressurized gas to a
fitting 665 that is in communication with the chamber. The fitting
665 is formed as part of, or is otherwise provided to a gasket seal
670 that follows the contour of the chamber. While the lower
portion of the seal 670 contacts the chamber, the upper portion of
the seal contacts a cover member or portion 675 that may be
integrally formed with the blower outlet, etc.
[0079] As schematically shown in FIG. 29, the axis 680 of the motor
outlet 660 is offset from the axis 685 of the chamber outlet 690
and/or blower outlet 695. Thus, any water that enters the chamber
from the humidifier will not be directly channeled to the motor
outlet 660.
[0080] In an alternative shown in FIG. 30, the axis 680 of the
motor outlet 660 can be aligned with the axis 700 of the
chamber/blower outlet 690, 695, yet any water from the humidifier
is not directly channeled to the motor outlet 660 because a chamber
705 is formed on a lower part of a connecting tube 710 that
connects the motor outlet to the flow generator outlet. The tube
has inlet and outlet portions 715, 720. The chamber 705 is provided
to store a volume of water that may be accidentally introduced into
the flow generator from the humidifier. This water will evaporate
and/or will be reintroduced into the air path to add extra
humidity, or the water can simply be emptied out by tilting or by
use of a drain. The arrangement in FIG. 30 can be used in the flow
generator shown in, for example, FIG. 14 of US patent application
publication no. US 2005/0103339 A1, incorporated herein by
reference in its entirety.
[0081] 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. 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,
bariatric 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.
* * * * *