(12) United States Patent
`Gunaratnam et al.
`
`(10) Patent N0.:
`(45) Date of Patent:
`
`US 6,691,707 B1
`Feb. 17, 2004
`
`US006691707B1
`
`(54) CONNECTOR FOR A RESPIRATORY MASK
`AND A RESPIRATORY MASK
`
`(75)
`
`Inventors: Michael K. Gunaratnam, Marsfield
`(AU); Joanne E. Drew, Balgowlah
`(AU); Geofirey Crumblin, Baulkham
`Hills (AU); Phillip Jenkinson, Epping
`(AU); Susan R. Lynch, Rodd Point
`(AU)
`
`(73) Assignee: ResMed Limited, North Ryde (AU)
`
`( * ) Notice:
`
`Subject to any disclaimer, the term of this
`patent is extended or adjusted under 35
`U.S.C. 154(b) by 0 days.
`
`(21) Appl. N0.: 09/594,775
`
`(22) Filed:
`
`Jun. 16, 2000
`
`(30)
`
`Foreign Application Priority Data
`
`Jun. 18, 1999
`
`(AU) .......................................... .. PO 1029
`
`Int. Cl.7 .............................................. .. A62B 18/02
`(51)
`(52) U.S. c1.
`............................ ..128/206.21;128/207.13
`(58) Field of Search ..................... .. 128/206.21, 207.13,
`128/207.18, 206.28, 205.27, 205.28, 204.18,
`202.27, 912, 207.12, 206.12, 206.15, 206.18
`
`(56)
`
`References Cited
`U.S. PATENT DOCUMENTS
`
`4,015,598 A *
`4,463,755 A
`4,794,921 A *
`5,018,519 A *
`
`4/1977 Brown ................ .. 128/203.23
`8/1984 Suzuki
`1/1989 Lindkvist ............. .. 128/203.29
`5/1991 Brown ................ .. 128/203.29
`
`5,560,354 A * 10/1996 Berth0n—J0nes
`. 128/205.25
`etal.
`.
`5,694,922 A * 12/1997 Palmer .......... ..
`128/202.27
`
`128/206.22
`5,871,011 A *
`2/1999 Howell et al.
`....... .. 128/205.25
`5,921,239 A *
`7/1999 McCall et al.
`5,937,851 A *
`8/1999 Scrowski et al.
`128/202.27
`5,975,077 A * 11/1999 Hofstetter et al.
`128/204.24
`6,196,223 B1 *
`3/2001 Belfer et al.
`......... .. 128/206.25
`FOREIGN PATENT DOCUMENTS
`
`CA
`DE
`W0
`
`1039144
`197 57 703 C1
`WO 98/34665
`
`9/1978
`10/1999
`8/1998
`
`* cited by examiner
`
`Primary Examirzer—Weilun Lo
`Assistant Examiner—Ter1r1a Mitchell
`
`(74) Attorney, Agent, or Firm—NiXon & Vanderhye, P.C.
`
`(57)
`
`ABSTRACT
`
`A connector includes a mask end for connecting with the
`interior of a respiratory mask, a supply conduit end, and a
`gas washout Vent passage having an inlet adjacent to, or
`forming part of, the mask end in fluid communication with
`the interior of the respiratory mask and an outlet in fluid
`communication with atmosphere. The Vent outlet of the Vent
`passage is disposed on the side of the connector remote from
`the mask end. A respiratory mask includes a mask shell, a
`mask inlet for connecting with the outlet of a breathable gas
`supply conduit, and a gas washout Vent passage. A Vent
`outlet is disposed on the side of the mask remote from the
`mask interior and is adapted to direct the washout gas in a
`direction substantially parallel to the longitudinal axis of the
`mask inlet and away from the mask inlet.
`
`14 Claims, 9 Drawing Sheets
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`US 6,691,707 B1
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`1
`CONNECTOR FOR A RESPIRATORY MASK
`AND A RESPIRATORY MASK
`
`BACKGROUND OF THE INVENTION
`
`1. Field of Invention
`
`The present invention relates to a connector for a respi-
`ratory mask and a respiratory mask.
`The invention has been developed primarily for use with
`a breathable gas supply apparatus in Continuous Positive
`Airway Pressure (CPAP)
`treatment of,
`for example,
`Obstructive Sleep Apnea (OSA) and other ventilatory assis-
`tance treatments, such as Non Invasive Positive Pressure
`Ventilation (NIPPV) and will be described hereinafter with
`reference to these applications. However, it will be appre-
`ciated that the invention is not limited to these particular
`fields of use and also finds application in, for example,
`assisted respiration, mechanical ventilation and the like.
`2. General Background and Related Art
`CPAP treatment is a common ameliorative treatment for
`
`breathing disorders including OSA. CPAP treatment, as
`described in U.S. Pat. No. 4,944,310, provides pressurized
`air or other breathable gas to the entrance of a patient’s
`airways at a pressure elevated above atmospheric pressure,
`typically in the range 3-20 cm H20.
`It is also known for the level of treatment pressure to vary
`during a period of treatment in accordance with patient need,
`that form of CPAP being known as automatically adjusting
`nasal CPAP treatment, as described in U.S. Pat. No. 5,245,
`995.
`
`NIPPV is another form of treatment for breathing disor-
`ders which can involve a relatively higher pressure of gas
`being provided in the patient mask during the inspiratory
`phase of respiration and a relatively lower pressure or
`atmospheric pressure being provided in the patient mask
`during the expiratory phase of respiration.
`In other NIPPV modes, the pressure can be made to vary
`in a complex manner throughout the respiratory cycle. For
`example,
`the pressure at the mask during inspiration or
`expiration can be varied through the period of treatment, as
`disclosed in the applicant’s international PCT patent appli-
`cation No. PCT/AU97/00631.
`Typically, the ventilatory assistance for CPAP or NIPPV
`treatment is delivered to the patient by way of a respiratory,
`preferably nasal, mask. Alternatively, a mouth mask or full
`face mask can be used. In this specification any reference to
`a mask is to be understood as incorporating a reference to a
`nasal mask, mouth mask or full face mask, unless otherwise
`specifically indicated.
`In this specification any reference to CPAP treatment is to
`be understood as embracing all of the above-described forms
`of ventilatory treatment or assistance.
`Breathable gas supply apparatus broadly comprise a flow
`generator constituted by a continuous source of air or other
`breathable gas generally in the form of a blower driven by
`an electric motor. The electric motor driving the blower is
`typically controlled by a servo-controller under the control
`of a micro controller unit. A hospital piped supply can also
`be used. The gas supply is connected to a conduit or tube
`which, in turn,
`is connected to the patient’s mask which
`incorporates, or has in close proximity, a gas washout vent
`for venting exhaled gases to the atmosphere. The gas wash-
`out vent is sometimes referred to as a C02 washout vent.
`As CPAP and NIPPV treatments are normally adminis-
`tered while the patient is sleeping, minimization of the noise
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`is desirable for both the comfort of the patient and any bed
`partner. The exhausting of exhaled gas to the atmosphere
`through the gas washout vent creates noise due to turbulence
`generated at a shear layer between the moving vented gases
`and the still atmospheric air.
`It is also desirable to locate the vent as close as possible
`to the mask in a location which encourages a circulation of
`flow within the mask so as to eliminate exhaled CO2 through
`the vent and encourage inhalation of the supplied breathable
`gas. In this way, the retention of CO2 within the mask is
`minimized. Further, by increasing the venting efficiency in
`this manner, the overall gas outflow is minimized, thereby
`reducing the opportunity for noise production.
`One approach to minimize the noise generated by the
`venting of the exhaled gas is to direct the gas along an
`exterior surface which is a smooth prolongation of an
`interior surface of the outlet of the gas washout vent. This
`reduces the interaction between the vented gas and the still
`atmospheric air and, thus, the noise generated.
`An example of the above approach is the AeroClick vent
`produced by MAP which has an annular vent passage that
`directs the exhaled gases along an adjacent cylindrical
`section of equal exterior diameter to the interior diameter of
`the annular vent. The AeroClick vent suffers from several
`
`disadvantages. Firstly, the annular vent is incorporated into
`a swivel mechanism which requires a certain amount of play
`or clearance in order to rotate freely. This play allows the
`components forming the interior and exterior surfaces of the
`annular vent passage to become misaligned and the size of
`the vent outlet being decreased from optimum in some
`regions and increased from optimum in other regions. The
`decreased area regions increase by the velocity of the gas
`flowing therethrough which increases noise and can produce
`an unpleasant whistling effect. Secondly, the flow of the gas
`from the vent outlet
`to a state where its velocity is in
`substantial equilbrium with the atmosphere is interrupted by
`an external shoulder closely downstream of the vent outlet.
`The shoulder is provided to locate the gas supply conduit.
`The stresses in the flow caused by the shoulder lead to the
`generation of noise. Additionally, the flow path from the gas
`conduit into the vent outlet is not smooth which introduces
`discontinuities into the flow which result in further noise
`
`generation.
`Further, the AeroClick vent and other prior art devices that
`are of a substantially cylindrical in-line configuration, the
`exhaled gas must thus be forced a relatively large distance
`(typically around 60 mm) before reaching the outlet to the
`atmosphere. This reduces CO2 washout efliciency, as noted
`above, and requires additional patient effort to force the gas
`against the direction of flow coming from the flow generator.
`It is an object of the present invention to substantially
`overcome or at least ameliorate the prior art disadvantages
`and, in particular, to reduce the noise generated by venting
`exhaled gases to the atmosphere.
`
`SUMMARY OF THE INVENTION
`
`Accordingly, in a first aspect, the present invention pro-
`vides a connector comprising:
`a mask end for connecting in fluid communication with
`the interior of a respiratory mask;
`a supply conduit end disposed at an angle to the mask end
`for connecting in fluid communication with the outlet
`of a breathable gas supply conduit; and
`a gas washout vent passage having an inlet adjacent to, or
`forming part of, the mask end in fluid communication
`
`11
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`US 6,691,707 B1
`
`3
`with the interior of the respiratory mask and an outlet
`in fluid communication with the atmosphere, the outlet
`including an interior surface that forms a smooth pro-
`longation with an adjacent exterior surface of the
`connector, the vent outlet is disposed on the side of the
`connector remote the mask end, has a generally part-
`annular cross section and is adapted to direct
`the
`washout gas in a direction substantially perpendicular
`to the longitudinal axis of the mask end and substan-
`tially parallel to the longitudinal axis of the supply
`conduit end towards the supply conduit end.
`The supply conduit end is preferably substantially per-
`pendicular to the mask end. The supply conduit end can also
`be angled at approximately 135 degrees to the mask end.
`Preferably, the connector includes a body portion and a
`cap portion, said body portion including said interior sur-
`face. The cap portion preferably also includes an interior
`surface spaced apart from the body portion interior surface,
`said body portion interior surface and said cap portion
`interior surface defining said vent passage therebetween.
`The cap portion is desirably detachable from the body
`portion. The cap portion and body portion are also desirably
`rigid and fixed relative to each other when attached. The
`exterior of the body portion preferably includes grooves or
`ridges adapted to engage ridges or grooves respectively on
`the interior of the cap portion to attach the cap portion to the
`body portion. One of the body portion or cap portion
`preferably also includes a spacer extending between said cap
`portion interior surface and said body portion exterior sur-
`face.
`
`In one form, the vent passage inlet is formed in the body
`portion adjacent to and downstream of the mask end, relative
`to the washout gas flow, and is in fluid communication with
`the mask interior via the body portion.
`In another form, the vent passage inlet comprises part of
`the mask end and is in direct fluid communication with the
`mask interior.
`
`The vent passage preferably comprises an inlet portion of
`relatively large cross-sectional area adjacent the vent pas-
`sage inlet and an outlet portion of relatively small cross-
`sectional area adjacent the vent passage outlet.
`The vent passage desirably comprises an inlet portion of
`constant cross—section, a relatively long outlet portion of
`constant cross-section and a relatively short transition por-
`tion of smoothly reducing cross-section extending from the
`inlet portion to the outlet portion. This shape reduces tur-
`bulence and affords a pressure drop from the interior of the
`mask to the outlet of the vent passage which reduces the
`pressure gradient at the outlet of the vent passage and, thus,
`reduces the noise generated.
`The vent passage can also include internal ribs and/or an
`internal
`tortuous path to increase the pressure drop,
`if
`required.
`The body portion is preferably of generally part toroidal
`shape. The cap portion is preferably of complimentary shape
`to a portion of the exterior of the body portion.
`The vent passage preferably curves around the exterior of
`the body portion.
`The connector desirably includes a swivel joiner at its
`supply conduit end, the exterior of the swivel joiner forming
`all, or a part, of said connector exterior surface.
`In one form, the supply conduit end of the connector
`forms a smooth prolongation with the supply conduit. The
`supply conduit end and the supply conduit desirably have a
`substantially equal external diameter.
`In another form, the swivel joiner forms a smooth pro-
`longation with the supply conduit. The swivel joiner and the
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`supply conduit having a substantially equal external diam-
`eter. The swivel joiner preferably includes an end of reduced
`external diameter adapted to be received within the interior
`of the supply conduit.
`the present
`In a second aspect,
`respiratory mask comprising:
`a mask shell defining an interior of the respiratory mask;
`a mask inlet for connecting in fluid communication with
`the outlet of a breathable gas supply conduit; and
`a gas washout vent passage having an inlet forming part
`of the mask shell and in fluid communication with the
`
`invention provides a
`
`interior of the respiratory mask and an outlet in fluid
`communication with the atmosphere, the outlet includ-
`ing an interior surface that forms a smooth prolongation
`with an adjacent exterior surface of the mask shell, the
`vent outlet is disposed on the side of the mask remote
`the mask interior and is adapted to direct the washout
`gas in a direction substantially parallel to the longitu-
`dinal axis of the mask inlet and away from the mask
`inlet.
`
`Preferably, the mask shell includes a body portion and a
`cap portion, said body portion including said interior sur-
`face. The cap portion preferably also includes an interior
`surface spaced apart from the body portion interior surface,
`said body portion interior surface and said cap portion
`interior surface defining said vent passage therebetween.
`The cap portion is desirably detachable from the body
`portion. The cap portion and body portion are also desirably
`rigid and fixed relative to each other when attached. The
`exterior of the body portion preferably includes grooves or
`ridges adapted to engage ridges or grooves respectively on
`the interior of the cap portion to attach the cap portion to the
`body portion. One of the body portion or cap portion
`preferably also includes a spacer extending between the
`interior surface of the cap portion and the exterior surface of
`the body portion.
`The vent passage preferably comprises an inlet portion of
`a relatively large cross-sectional area adjacent
`the vent
`passage inlet and an outlet portion of a relatively small
`cross-sectional area adjacent the vent passage outlet.
`The vent passage desirably comprises a relatively long
`inlet portion of constant cross-section, a relatively long
`outlet portion of constant cross-section and a transition
`portion of smoothly reducing cross-section extending from
`the inlet portion to the outlet portion.
`The vent passage preferably substantially follows the
`shape of the exterior of the body portion.
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`FIG. 1 is a side view of a first embodiment of a connector
`in accordance with the first aspect of the invention, shown
`attached to a nasal respiratory mask and forehead support;
`FIG. 2 is a cross-sectional side view of the connector
`shown in FIG. 1;
`FIG. 3 is a perspective view of the connector shown in
`FIG. 1;
`FIG. 4 is a perspective view of the connector shown in
`FIG. 1 with the cap portion removed;
`FIG. 5 is an underside perspective view of the cap portion
`of the connector shown in FIG. 1;
`FIG. 6 is a cross-sectional side view of a second embodi-
`
`ment of a connector in accordance with the first aspect of the
`invention;
`FIG. 7 is a cross-sectional side view of a third embodi-
`
`ment of the connector in accordance with the first aspect of
`the invention;
`
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`US 6,691,707 B1
`
`5
`FIG. 8 is a cross-sectional side view of a first embodiment
`of a respiratory mask in accordance with the second aspect
`of the invention; and
`FIG. 9 is a cross-sectional side View of a fourth embodi-
`
`ment of the connector in accordance with the first aspect of
`the invention
`
`DETAILED DESCRIPTION OF THE
`PREFERRED EMBODIMENTS
`
`FIGS. 1 to 5 show a first embodiment of the first aspect
`of the invention in the form of connector 10. The connector
`
`10 is shown attached to a nasal respiratory mask 12 and
`forehead support device 14. The connector 10 is also suit-
`able for use with a full face (i.e., nose and mouth) respiratory
`mask.
`
`The mask 12 comprises a substantially rigid mask shell
`15, a flexible mask cushion 16 and two slotted lower head
`strap connectors 18 (only one connector shown).
`The forehead support device 14 includes a lower portion
`20 which is pivotally mounted to an upper portion 22. The
`upper portion 22 includes forehead cushions 24 and two
`slotted upper head strap connectors 26 (only one cushion/
`connector shown).
`As best shown in FIG. 2, the connector 10 includes a mask
`end 28 having a longitudinal axis A—A for connecting in
`fluid communication with the interior of the respiratory
`mask 12 and a supply conduit end 30 having a longitudinal
`axis B—B disposed substantially perpendicularly to the
`mask end 28 for connecting in fluid communication with the
`outlet of a breathable gas supply conduit 31. The mask end
`28 is rotatably coupled to the mask shell 15 by a retaining
`ring 29. The close proximity of the inlet ports 41, and the
`vent passage 32 overall,
`to the interior of the mask 12
`advantageously increases CO2 washout efficiency.
`The connector 10 also includes a gas washout vent
`passage, indicated generally by the reference numeral 32, a
`body portion 34, a detachable cap portion 36 and a detach-
`able swivel joiner 38. The conduit 31 is a non-rotatable
`friction push fit over end 38a of the swivel joiner 38. The
`end 38b of the swivel joiner 38 is a rotatable snap-engage fit
`with reduced diameter portion 39 of the body portion 34.
`The portion 39 is formed from resilient fingers to allow
`flexing during snap-engagement with the swivel joiner 38.
`The vent passage 32 includes a pair of inlet ports 41 (see
`FIG. 4) formed in the body portion 34 of the connector 10
`adjacent the mask end 28. The inlet ports 41 are in fluid
`communication with the interior of the mask 12 via the mask
`end 28. The vent passage 32 also includes an outlet 40
`opening to the atmosphere. The outlet 40 includes an interior
`surface 42 (comprising an exterior surface of the body
`portion 34) that
`forms a smooth prolongation with an
`adjacent exterior surface 44 of the body portion 34. The
`smooth prolongation between the interior surface 42 and
`exterior surface 44 reduces noise by allowing the exhaled
`gases to vent along a continuous surface, as previously
`described. In order to minimize interruptions or disturbances
`that could generate turbulence downstream of the outlet 40,
`and thus noise, the adjacent exterior surfaces 46, 48 of the
`swivel joiner 38 and the gas supply conduit 31 respectively
`are also formed as smooth prolongations of the interior
`surface 42 and adjacent exterior surface 44.
`As best shown in FIG. 3, the vent passage outlet 40 forms
`an arc and is of generally semi-circular cross-section sub-
`tending an angle of approximately 180° and is located on the
`side of the connector 10 remote from the mask end 28 and,
`thus, the mask 12. The shape of the outlet 40 can also be
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`understood by FIG. 5, which shows the curved upper edge
`of the cap 36 that forms the outer portion of the vent passage
`32. This ensures that gas is only vented along surfaces
`displaced, and facing away, from the mask 12 and the
`patient, which again minimizes the risk of the vented gases
`encountering noise-producing obstructions.
`Returning to FIG. 2, it can be seen that the vent passage
`32 comprises an inlet portion 50 of relatively large cross-
`sectional area compared to an outlet portion 52 of relatively
`small cross-sectional area. In this example,
`the distance
`between the interior surface 42 of the body portion 34 and
`the cap 36, which defines the vent passage 32, is larger at the
`inlet portion 50 than at the outlet portion 52. This provides
`a substantial pressure drop across the vent passage 32 and
`reduces the pressure drop between the outlet 40 and sur-
`rounding atmospheric air, again minimizing noise produc-
`tion. Also, the outlet portion 52 is relatively long in order to
`allow the gas to approach a laminar state and, thus, minimize
`turbulence before the gas exits to the atmosphere. Asmooth
`tapering transition portion 54 is disposed between the inlet
`portion 50 and the outlet portion 52 which minimizes noise
`production by minimizing the introduction of any disconti-
`nuities into the gas flow.
`As best shown in FIGS. 3 and 4, the body portion 34
`includes grooves 56 which are adapted to engage with ridges
`58 provided on the cap portion 36 to allow the cap portion
`36 to be manually attachable/detachable to/from the body
`portion 34 for ease of cleaning and replacement. As best
`shown in FIG. 5, the cap portion 36 also includes an interior
`strengthening rib 60 to provide rigidity and ensure the
`cross-sectional area of the vent passage 32 is not reduced
`due to external pressure, as may be caused by the patient
`rolling over onto their face during sleep. The detachable cap
`portion 36 also makes disassembly for cleaning easier and
`allows cap portions of various sizes to be used with a single
`body portion 34, thereby allowing the size and shape of the
`vent passage to be easily and quickly varied for particular
`treatment applications.
`Although the connector 10 has been described with ref-
`erence to the swivel joiner 38 being interposed between the
`connector 10 and the breathable gas supply conduit 31, it
`will be appreciated that the conduit can be joined directly to
`the body portion 34 if the ability to swivel is not required or
`if a swivel is provided elsewhere in the gas supply circuit.
`In that case,
`it
`is, of course, desirable for the external
`diameter of the gas supply conduit 31 to be equal to the
`adjacent external diameter of the exterior surface of the body
`portion 34.
`Asecond embodiment of connector 80 in accordance with
`
`the first aspect of the invention is shown in FIG. 6. Like
`reference numerals to those used in describing the first
`embodiment are used to indicate like features in the second
`embodiment.
`
`The primary difference between the connector 10 and
`connector 80 is that the inlet ports 41 are omitted and an inlet
`port 82 of the gas washout vent passage 32 is incorporated
`into the mask end 28 of the connector 80. Thus providing
`direct fluid communication between the interior of the mask
`
`12 and the vent passage 32 and further minimizing CO2
`retention. The inlet portion 50 of the vent passage 32 also
`provides a relatively long distance over which a gradual
`reduction in pressure can be achieved. Further, the interior
`surface of the vent passage outlet 40 forms a smooth
`prolongation with the adjacent exterior surface 46 of the
`swivel joiner 38 rather than the body portion 34, as with the
`first embodiment.
`
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`US 6,691,707 B1
`
`7
`FIG. 7 shows a third embodiment of the connector 90
`according to the first aspect of the invention. Like reference
`numerals to those used in describing the first embodiment
`will again be used to indicate like features in the third
`embodiment. The connector 90 also has the vent passage 32
`in direct fluid communication with the interior of the mask
`12. However, in this embodiment, an inlet port 92 is formed
`in the mask shell 15.
`FIG. 9 shows a fourth embodiment of the connector 130
`according to the first aspect of the invention. Like reference
`numerals to those used in describing the first embodiment
`will again be used to indicate like features in the fourth
`embodiment. The connector 130 also has an inlet port 132
`formed in the mask shell 15, similar to the third embodi-
`ment. However, in this embodiment, both the interior sur-
`face 42 and the smoothly prolongating adjacent exterior
`surface 46 are provided on the swivel joiner 38. As the gas
`vents to the atmosphere downstream of the join 134 between
`the swivel joiner 38 and the body portion 34, then any gas
`leaking through the join 134 cannot disturb the flow of gas
`at, or after, the outlet 40. In this way, a further opportunity
`for turbulence, and thus noise generation, is eliminated.
`FIG. 8 shows a first embodiment of a nasal respiratory
`mask 100 in accordance with the second aspect of the
`invention. The mask 100 includes a mask shell 102 and a
`mask cushion 104. The mask shell 102 includes a mask inlet
`
`106 for connecting in fluid communication with the outlet of
`the breathable gas supply conduit 108. The mask 100
`includes a gas washout vent passage indicated generally by
`the reference numeral 110.
`
`The mask shell 102 is comprised of a body portion 112
`and a detachable/attachable cap portion 114. The vent pas-
`sage 110 includes an inlet port 116 formed in the body
`portion 112 of the mask shell 102. The inlet port 116 is in
`direct fluid communication with the interior of the mask 100.
`
`The vent passage 110 also includes an outlet 118 in fluid
`communication with the atmosphere. The outlet 118
`includes an interior surface 120 on the exterior of the body
`portion 112 that forms a smooth prolongation with an
`adjacent surface 122 also provided on the exterior of the
`body portion 112. The outlet 118 is adapted to direct the
`washout gas in a direction substantially parallel
`to the
`longitudinal axis of the mask inlet 106 and away from the
`mask inlet 106.
`
`the noise produced by
`As with earlier embodiments,
`venting the exhaled gas to the atmosphere is minimized by
`directing the vented gas on a smooth continuing surface
`before and after the outlet 118 and away from the mask 100,
`the patient and other potential disturbances. Additionally, as
`with the earlier connector embodiments, the cap portion 114
`is detachable from the body portion 112 for cleaning and or
`replacement with a cap portion of same, or different, size or
`shape. The vent passage 110 also similarly comprises an
`inlet portion 124 of relatively large cross-sectional area, a
`relatively long outlet portion 126 of relatively small cross-
`sectional area and a transition portion 128 of smoothly
`reducing cross-section extending from the inlet portion 124
`to the outlet portion 126.
`Although the invention has been described with reference
`to the preferred embodiments, it will be appreciated by those
`sldlled in the art that the invention may be embodied in
`many other forms.
`We claim:
`
`1. A connector comprising:
`a mask end having a longitudinal axis for connecting in
`fluid communication with an interior of a respiratory
`mask;
`
`10
`
`15
`
`20
`
`25
`
`30
`
`35
`
`40
`
`45
`
`50
`
`55
`
`60
`
`65
`
`8
`a supply conduit end having a longitudinal axis and being
`disposed at an angle to the mask end for connecting in
`fluid communication with an outlet of a breathable gas
`supply conduit;
`a gas washout vent passage having an inlet adjacent to, or
`forming part of, the mask end in fluid communication
`with the interior of the respiratory mask and an outlet
`in fluid communication with the atmosphere, the outlet
`including an interior surface that forms a smooth pro-
`longation with an adjacent exterior surface of the
`connector,
`the outlet
`is disposed on a side of the
`connector remote from the mask end,
`is generally
`semi-circular when viewed in cross-section and is
`
`adapted to direct washout gas in a direction substan-
`tially perpendicular to the longitudinal axis of the mask
`end and substantially parallel to the longitudinal axis of
`the supply conduit end towards the supply conduit;
`a body portion including an interior surface and an
`exterior surface; and
`a cap portion including an interior surface spaced apart
`from the interior surface of the body portion, said
`interior surface of the body portion and said interior
`surface of the cap portion defining said vent passage
`therebetween, wherein the inlet of the vent passage
`comprises part of the mask end and is in direct fluid
`communication with the interior of the respiratory
`mask.
`2. The connector as claimed in claim 1, wherein the vent
`passage comprises an inlet portion of a relatively large
`cross-sectional area adjacent the inlet of the vent passage
`and an outlet portion of a relatively small cross-sectional
`area adjacent the vent passage outlet.
`3. The connector as claimed in claim 1, wherein the vent
`passage comprises an inlet portion of a substantially con-
`stant cross-section, a relatively long outlet portion of con-
`stant cross-section and a relatively short transition portion of
`smoothly reducing cross-section extending from the inlet
`portion to the outlet portion.
`4. The connector as claimed in claim 1, wherein the vent
`passage includes internal ribs and/or an internal tortuous
`path.
`5. The connector as claimed in claim 1, wherein the body
`portion is of generally part toroidal shape.
`6. The connector as claimed in claim 1, wherein the cap
`portion is of complimentary shape to a portion of the exterior
`surface of the body portion.
`7. The connector as claimed in claim 1, wherein the vent
`passage curves around the exterior surface of the body
`portion.
`8. The connector as claimed in claim 1, wherein the
`supply conduit end of the connector forms a smooth pro-
`longation with the supply conduit.
`9. The connector as claimed in claim 1, wherein the
`supply conduit end and the supply conduit have a substan-
`tially equal external diameter.
`10. A connector comprising:
`a mask end having a longitudinal axis for connecting in
`fluid communication with an interior of a respiratory
`mask;
`a supply conduit end having a longitudinal axis and being
`disposed at an angle to the mask end for connecting in
`fluid communication with an outlet of a breathable gas
`supply conduit;
`
`14
`
`14
`
`

`
`US 6,691,707 B1
`
`9
`a gas washout vent passage having an inlet adjacent to, or
`forming part of, the mask end in fluid communication
`with the interior of the respiratory mask and an outlet
`in fluid communication with the atmosphere, the outlet
`including an interior surface that forms a smooth pro-
`longation with an adjacent exterior surface of the
`connector,
`the outlet
`is disposed on a side of the
`connector remote from the mask end,
`is generally
`semi-circular when viewed in cross-section and is
`
`adapted to direct washout gas in a direction substan-
`tially perpendicular to the longitudinal axis of the mask
`end and substantially parallel to the longitudinal axis of
`the supply conduit end towards the supply conduit;
`a body portion including an interior surface and an
`exterior surface; and
`a cap portion including an interior surface spaced apart
`from the interior surface of the body portion, said
`interior surface of the body portion and said interior
`surface of the cap portion defining said Vent passage
`therebetween, further comprising a swivel joiner at the
`supply conduit end, an exterior surface of the swivel
`joiner forming at least a part of the exterior surface of
`the connector.
`11.