12 United States Patent
`
`10 Patent N0.:
`
`9
`9
`Us 6 554 260 B1
`
`Lipscombe et al.
`
`(45) Date of Patent:
`
`Apr. 29, 2003
`
`US006554260B1
`
`(54) HUMIDIFIER FOR BREATHABLE GAS
`APPARATUS
`
`(75)
`
`Inventors: Matthew Lipscombe, Camperdown
`(AU), Richard L. Jones, Beecroft (AU)
`.
`.
`.
`(73) Assigneez ResMed Limited, North Ryde (AU)
`.
`.
`.
`.
`.
`( 4 ) Notice:
`Subject to any disclaimer, the term of this
`patent is extended or adjusted under 35
`U.S.C. 154(b) by 0 days.
`
`5,168,866 A * 12/1992 Montgomery ........ .. 128/204.14
`5,231,979 A
`8/1993 Rose et al.
`5,245,995 A
`9/1993 Sullivan et al.
`
`7/1996 Mechlenburg
`5537997 A
`13/1336 ls)i(r)il£)isI:)Ir1e,ethal.etal.
`§:§3<8i:<8i£ 2
`1/2000 M t h tt
`t
`l
`D419,658 S
`10/2000 Hfblcflzwhefieaet al.
`6,135,432 A
`2/2001 W'th ll ................ .. 128/204.14
`6,189,870 B1 *
`1/2002 Helbbalewhite et al.
`6,338,473 B1
`FOREIGN PATENT DOCUMENTS
`
`(21) Appl. No.: 09/689,775
`
`(22) Filed:
`
`Oct. 13, 2000
`
`EP
`WO
`
`0 845 277 A2
`PCT/AU97/00631
`
`6/1998
`9/1997
`
`OTHER PUBLICATIONS
`
`(30)
`
`Foreign Application Priority Data
`
`Oct. 13, 1999
`
`(AU) ............................................ .. PQ3390
`
`Product Brochure for Sullivan® HumidAireTM, ResMed
`Limited, ©2001, 4 pages.
`
`* cited by examiner
`
`Primary Examiner—C. Scott Bushey
`(74) Attorney, Agent, or Firm—Pillsbury Winthrop LLP
`
`(57)
`
`ABSTRACT
`
`A humidifier for use with a breathable gas supply apparatus
`includes a hollow body adapted for partial filling with Water
`to a predetermined maximum Water level, a gas inlet to the
`body above the maximum Water level and a gas outlet from
`the body above the maximum Water level. The humidifier
`further includes a constant temperature heating element for
`heating the Water and/or an adjustable flow divider adapted
`to divide the interior of the body above the maximum Water
`level into a relatively dry gas region and a relatively Wet gas
`region. The position of the divider is variable so as to vary
`the relative proportion of the gas flowing from the inlet to
`the outlet that passes through the relatively dry and rela-
`tively Wet gas regions to thereby vary the amount of humidi-
`fication thereof.
`
`14 Claims, 14 Drawing Sheets
`
`Int. Cl.7 ................................................. .. B01F 3/04
`(51)
`(52) U.s. Cl.
`.................... .. 261/142; 261/63; 261/119.1;
`128/203.25; 128/203.27; 128/204.14
`(58) Field of Search ............................ .. 261/30, 38, 63,
`261/119.1, 127, 131, 142, DIG. 29, 128/203.17,
`203.25, 203.27, 204.14
`
`(56)
`
`References Cited
`U.S. PATENT DOCUMENTS
`
`2/1915 Cunningham ........ .. 128/203.25
`1,129,171 A *
`9/1935 Grady ...................... .. 261/142
`2,013,270 A *
`2,535,516 A * 12/1950 Resek . . . . . . . . . .
`. . . . . .. 261/142
`2,941,528 A *
`6/1960 Fabian et al.
`..
`128/203.25
`3,588,057 A *
`6/1971 Breiling . . . . . . . .
`. . . .. 128/203.25
`3,661,368 A *
`5/1972 Metivier .............. .. 128/203.25
`3,806,102 A *
`4/1974 Valenta et al.
`............ .. 261/142
`3,954,920 A *
`5/1976 Heath ....................... .. 261/142
`4,203,027 A
`5/1980 O’Hare et al.
`4,216,176 A *
`8/1980 Tanaka ..................... .. 261/142
`4,621,632 A
`11/1986 Bartels et al.
`4,741,871 A *
`5/1988 Payha ................... .. 261/119.1
`4,944,310 A
`7/1990 Sullivan
`
`
`
`
`
`Apex Medical Corp.
`Exhibit 1005
`
`Apex Medical Corp.
`Exhibit 1005
`
`

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`U.S. Patent
`
`Apr. 29, 2003
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`Sheet 1 of 14
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`US 6,554,260 B1
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`Apex Medical Corp.
`Exhibit 1005
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`Apex Medical Corp.
`Exhibit 1005
`
`

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`U.S. Patent
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`Apr. 29, 2003
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`Sheet 2 of 14
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`Apex Medical Corp.
`Exhibit 1005
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`Apex Medical Corp.
`Exhibit 1005
`
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`

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`U.S. Patent
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`Apr. 29, 2003
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`Sheet 3 of 14
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`US 6,554,260 B1
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`x..mmmAE
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`Apex Medical Corp.
`Exhibit 1005
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`U.S. Patent
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`Apr. 29, 2003
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`Sheet 4 of 14
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`mm
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`x..mmmAE
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`Apex Medical Corp.
`Exhibit 1005
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`U.S. Patent
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`Apr. 29, 2003
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`Sheet 5 of 14
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`FIG. 8
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`Apex Medical Corp.
`Exhibit 1005
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`Apex Medical Corp.
`Exhibit 1005
`
`

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`U.S. Patent
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`Apr. 29, 2003
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`Sheet 6 of 14
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`Apex Medical Corp.
`Exhibit 1005
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`Apex Medical Corp.
`Exhibit 1005
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`

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`U.S. Patent
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`Apr. 29, 2003
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`Sheet 7 of 14
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`US 6,554,260 B1
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`Apex Medical Corp.
`Exhibit 1005
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`Apex Medical Corp.
`Exhibit 1005
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`

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`U.S. Patent
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`Apr. 29, 2003
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`Sheet 8 of 14
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`Apex Medical Corp.
`Exhibit 1005
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`Apex Medical Corp.
`Exhibit 1005
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`

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`U.S. Patent
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`Apr. 29, 2003
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`Sheet 9 of 14
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`Apex Medical Corp.
`Exhibit 1005
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`Apex Medical Corp.
`Exhibit 1005
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`

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`U.S. Patent
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`Apr. 29, 2003
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`Sheet 10 of 14
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`x..mmmAE
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`Exhibit 1005
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`

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`U.S. Patent
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`Apr. 29, 2003
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`Sheet 11 of 14
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`US 6,554,260 B1
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`Apex Medical Corp.
`Exhibit 1005
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`Apex Medical Corp.
`Exhibit 1005
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`

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`U.S. Patent
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`Apr. 29, 2003
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`Sheet 12 of 14
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`US 6,554,260 B1
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`Apex Medical Corp.
`Exhibit 1005
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`Apex Medical Corp.
`Exhibit 1005
`
`

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`U.S. Patent
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`Apr. 29, 2003
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`Sheet 13 of 14
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`US 6,554,260 B1
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`Apex Medical Corp.
`Exhibit 1005
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`Apex Medical Corp.
`Exhibit 1005
`
`

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`U.S. Patent
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`Apr. 29, 2003
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`Sheet 14 of 14
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`US 6,554,260 B1
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`Apex Medical Corp.
`Exhibit 1005
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`Apex Medical Corp.
`Exhibit 1005
`
`

`
`US 6,554,260 B1
`
`1
`HUMIDIFIER FOR BREATHABLE GAS
`APPARATUS
`
`FIELD OF THE INVENTION
`
`The present invention relates to a humidifier.
`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.
`
`BACKGROUND OF THE INVENTION
`
`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 pressurised
`air or other breathable gas to the entrance of a patient’s
`airways at a pressure elevated above atmospheric pressure,
`typically in the range 4-20 cm H2O.
`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 nasal mask.
`Alternatively, a mouth mask or full face mask or nasal
`prongs 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, full face mask or nasal prongs.
`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 or 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 a patient mask which
`incorporates, or has in close proximity, an exhaust to atmo-
`sphere for venting exhaled gases.
`In order to prevent drying of the patient’s airways during
`use of a breathable gas supply apparatus it is known to pass
`the gas through a humidifier before supplying the gas to the
`patient. Humidification is achieved by passing the air over a
`water surface within a humidifier so that the gas absorbs
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`moisture from the water before being delivered to the
`patient. The two main types of humidifier are passive, where
`the water is not heated, and active, where the water is heated.
`A known passive humidifier is the applicant’s Passover
`(Trade Mark) humidifier. Other passive humidifiers are
`disclosed in U.S. Pat. Nos. 5,231,979, 5,537,997 and 5,598,
`837.
`
`A known active humidifier is the applicant’s HumidAire
`(Trade Mark) which heats the water in the humidifier via a
`thermostatically controlled electric heating element. The
`temperature of the water is set manually by the patient. The
`HumidAire humidifier also has a built in safety feature to
`prevent the heater element reaching excessive temperatures
`under fault conditions.
`
`European patent application No. EP 0845277 discloses an
`active humidifier that includes a thermostatically controlled
`electric heating plate. Active humidifiers are also disclosed
`in U.S. Pat. Nos. 4,621,632 and 4,203,027.
`A disadvantage of known active humidifiers is the
`expense of the heating elements and associated thermostatic
`temperature control equipment.
`A disadvantage of known passive humidifiers is an inabil-
`ity to easily vary the amount of humidification of the gas.
`It is an object of the present invention to substantially
`overcome or at least ameliorate one or more of the above
`
`disadvantages.
`
`SUMMARY OF THE INVENTION
`
`Accordingly, in a first aspect, the present invention pro-
`vides a humidifier for use with a breathable gas supply
`apparatus, said humidifier comprising:
`a hollow body adapted for partial filling with water up to
`a predetermined maximum water level;
`a gas inlet to the body above the maximum water level;
`a gas outlet from the body above the maximum water
`level; and
`a constant temperature heating element for heating the
`water.
`
`is disposed
`
`the heating element
`
`In one embodiment,
`within the body.
`In another embodiment, the heating element is disposed
`external the body.
`invention provides a
`the present
`In a second aspect,
`humidifier for use with a breathable gas supply apparatus,
`said humidifier comprising:
`a hollow body adapted for partial filling with water to a
`predetermined maximum water level;
`a gas inlet to the body above the maximum water level;
`a gas outlet from the body above the maximum water
`level;
`means to heat the water, in the body; and
`an adjustable flow divider adapted to divide the interior of
`the body above the maximum water level into a rela-
`tively dry gas region and a relatively wet gas region,
`wherein the position of the divider is variable so as to
`vary the relative proportion of the gas flowing from the
`inlet to the outlet that passes through the relatively dry
`and relatively wet gas regions to thereby vary the
`amount of humidification thereof.
`Preferably, the position of the divider is variable between
`a first position in which all of the gas is diverted to the
`relatively wet gas region for maximum humidification, and
`a second position in which all of the gas is diverted to the
`relatively dry gas region for minimum humidification.
`
`Apex Medical Corp.
`Exhibit 1005
`
`Apex Medical Corp.
`Exhibit 1005
`
`

`
`US 6,554,260 B1
`
`3
`The heating means is preferably a constant temperature
`heating element, such as a self regulating wire.
`The humidifier desirably also includes a storage reservoir
`adapted to replenish the water in the body.
`The divider preferably also includes baffle plates. The
`position of the baffle plates can be fixed or adjustable.
`In one embodiment, the divider is a generally planar plate
`of substantially complimentary cross section to the interior
`of the body above the maximum water level. The plate
`preferably includes a threaded hole adapted to engage a
`threaded rod, wherein rotation of the rod causes the plate to
`move between the first and second positions. The exterior of
`the plate preferably forms a substantially fluid-tight seal
`with the interior of the body.
`In another embodiment, the divider includes a first end
`remote the gas inlet and the gas outlet and a second end
`adjacent the gas inlet and the gas outlet, wherein the divider
`is adapted to rotate about or near the first end to cause the
`second end to move between the first and second positions.
`In a further embodiment, the divider includes a first and
`second end adjacent the gas inlet and the gas outlet, wherein
`the divider is adapted to rotate about or near its centre to
`cause the first and second ends to move between the first and
`
`second positions.
`In a third aspect, the present invention provides a humidi-
`fier for use with a breathable gas supply apparatus, said
`humidifier comprising:
`a hollow body adapted for partial filling with water to a
`predetermined maximum water level;
`a gas inlet to the body above the maximum water level;
`a gas outlet from the body above the maximum water
`level;
`a constant temperature heating element for heating the
`water; and
`an adjustable flow divider adapted to divide the interior of
`the body above the maximum water level into a rela-
`tively dry gas region and a relatively wet gas region,
`wherein the position of the divider is variable so as to
`vary the relative proportion of the gas flowing from the
`inlet to the outlet that passes through the relatively dry
`and relatively wet gas regions to thereby vary the
`amount of humidification thereof.
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`BRIEF DESCRIPTION OF THE DRAWINGS
`Preferred embodiments of the invention will now be
`
`45
`
`described, by way of examples only, with reference to the
`accompanying drawings in which:
`FIG. 1 is an exploded perspective view of a humidifier
`according to a first embodiment of the invention;
`FIG. 2 is a front view of a humidifier according to a
`second embodiment of the invention;
`FIG. 3 is a top view of the humidifier shown in FIG. 2;
`FIG. 4 is a side view of the humidifier shown in FIG. 2;
`FIG. 5 is a partial cross sectional view along line 5,6—5,6
`of FIG. 3 or the humidifier shown in FIG. 2 with the flow
`
`dividing plate in a minimum humidification position;
`FIG. 6 is a partial cross sectional view along line 5,6—5,6
`of FIG. 3 of the humidifier shown in FIG. 2 with the flow
`
`dividing plate in a maximum humidification position;
`FIG. 7 is a lower perspective view of the flow divider of
`the humidifier shown in FIG. 2;
`FIG. 8 is an upper perspective view of the control knob of
`the humidifier shown in FIG. 2;
`FIG. 9 is an upper perspective view of an embodiment of
`a heating element suitable for use with the humidifier shown
`in FIG. 2;
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`FIG. 10 is an upper perspective view of another embodi-
`ment of a heating element;
`FIG. 11 is a cross sectional view of a humidifier according
`to a third embodiment of the invention;
`FIG. 12 is a partial cross sectional view of a humidifier
`according to a fourth embodiment of the invention;
`FIG. 13 is a lower perspective view of an embodiment of
`a flow dividing plate shown;
`FIG. 14 is a cross sectional view of an embodiment of a
`
`heating element assembly;
`FIG. 15 is a cross sectional view of a humidifier according
`to a sixth embodiment of the invention;
`FIG. 16 is a cross sectional view of a humidifier according
`to a seventh embodiment of the invention with the flow
`
`dividing plate in a maximum humidification position;
`FIG. 17 is a cross sectional view of the humidifier of FIG.
`
`15 with the flow dividing plate in a minimum humidification
`position; and
`FIG. 18 is a cross sectional view of another embodiment
`
`of a heating element assembly.
`
`DETAILED DESCRIPTION OF THE
`PREFERRED EMBODIMENTS
`
`FIG. 1 is an exploded view of a breathable gas supply
`apparatus 20 which comprises a flow generator 22, a first
`embodiment of a humidifier 24 according to the invention,
`an anti-bacterial filter 26 and a heating element 30. The filter
`26 is operatively positioned between the outlet of the flow
`generator 22 (not shown) and the inlet 28 of the humidifier
`24. In another embodiment (nor shown), the filter is opera-
`tively positioned between the outlet of the humidifier and the
`patient. In the latter, the filter reduces the transfer of bacteria
`from the patient to the humidifier, and vice-versa.
`The humidifier 24 includes a control knob 32 which can
`
`be rotated in order to vary the amount of humidification of
`the gas flowing through the humidifier between a maximum
`and minimum amount. The components of the humidifier 24
`which permit this adjustable humidification will be more
`completely described with reference to the embodiments of
`the invention shown in FIGS. 2 to 9, 11, 12, 13, 14, 15, 16
`and 17.
`
`The heating element 30 is of self regulating, constant
`temperature type. The heating element 30 advantageously
`simplifies the humidifier and breathable gas supply appara-
`tus overall by obviating the need for thermostatic tempera-
`ture control equipment.
`The heating element 30 is positioned external and under
`the humidifier. In another embodiment (not shown),
`the
`heating element is suitably insulated and/or water proofed
`and positioned inside the body of the humidifier.
`A second embodiment of a humidifier 40 is shown in
`FIGS. 2 to 9. As best shown in FIGS. 2 to 4, the humidifier
`40 includes a hollow body formed from an upper body
`portion 42 and a lower body portion 44. Afluid tight seal 46
`is disposed between the upper and lower body portions 42
`and 44.
`
`The upper body portion 42 includes a gas inlet 48 and a
`gas outlet 50.
`As best shown in FIG. 5, the upper body portion 42 also
`includes an opening 52 through which passes a threaded
`shaft 54. The shaft 54 depends from an external control knob
`56.
`
`A fluid tight seal 58 is provided around the shaft adjacent
`the knob 56 and the boss 52. The upper casing 42 includes
`
`Apex Medical Corp.
`Exhibit 1005
`
`Apex Medical Corp.
`Exhibit 1005
`
`

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`US 6,554,260 B1
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`5
`internal side walls 60 which are
`substantially parallel
`adapted to provide a substantially fluid tight seal with the
`external edges 61 of a flow dividing plate 62. However, a
`fluid tight seal is not critical.
`The plate 62 includes a central threaded boss 64 which
`threadably engages the shaft 54. Rotation of the knob 56
`causes the boss 64, and thus the plate 62, to travel along the
`shaft 54 between the lower most position shown in FIG. 5
`and upper most position shown in FIG. 6.
`The lower body portion 44 is adapted to be filled with
`water to a level approximately 10 mm below the seal 46.
`When connected to a breathable gas supply apparatus, the
`humidifier 40 is positioned directly above a heating element
`which heats the water and causes water vapour to rise from
`the upper surface thereof. The upper body portion 42 and
`lower casing 44 together define the boundaries of the interior
`66 of the humidifier 40. The plate 62 affectively divides the
`interior 66 above the water surface into a relatively dry gas
`region 68 above the plate 62 and a relatively wet gas region
`70 below the plate 62.
`When the knob 56 is rotated to position the plate 62 in the
`lowermost position shown in FIG. 5, the gas (normally air)
`pumped from the flow generator the inlet 48 of the humidi-
`fier 40 passes only through Me dry region 68 and therefore
`undergoes minimal or zero humidification.
`When the knob 56 is rotated to position the plate 62 in the
`uppermost position shown in FIG. 6, the gas passes only
`through the wet region 70 and therefore undergoes maxi-
`mum humidification.
`
`When the knob 56 is rotated to position the plate 62
`intermediate the lowermost and uppermost position shown
`in FIGS. 5 and 6 respectively, then some of the supplied gas
`passes through the dry gas region 68 (and is not humidified)
`and some of the gas passes through the wet gas region 70
`(and is humidified), which results in partial humidification
`overall. In this way, the adjustable plate 62 advantageously
`allows the amount of humidification of the supplied gas to
`be quickly and easily varied to suit individual user needs,
`comfort requirements,
`treatment regimes and changing
`atmospheric conditions.
`The plate 62 is shown in isolation in FIG. 7 in which it can
`be seen that the boss 64 has a internal thread 72. The control
`knob 56 and shaft 54 are shown in isolation in FIG. 8 and
`
`it can be seen that the shaft 54 has an internal groove 74
`which engages the thread 72 of the boss 64. The upper
`surface of the control knob 56 has two depressions 76 to
`facilitate gripping of the knob 56 by a user’s fingers.
`FIG. 9 shows a constant temperature heating element 78
`suitable for use with the humidifier 40 shown in FIGS. 2 to
`
`8. The heating element 78 comprises a length of self
`regulating wire 80, for example LSH-10, manufactured by
`Letco Products, Inc Texas (USA), which is wound around a
`core 82, for example Noryl, manufactured by General Elec-
`tric. The self regulating wire 80 is able to be connected
`directly to mains power supply and, as mentioned above,
`advantageously obviates the need for thermostatic control
`equipment.
`temperature heating
`FIG. 10 shows another constant
`element 84. The heating element 84 comprises a self regu-
`lating film 85 with power leads 86 and 87, for example
`manufactured by ITW, Illinios (USA), which is attached to
`a plate 88, for example Noryl.
`FIG. 11 shows a third embodiment of a humidifier 90.
`
`Like reference numerals to those used in describing the
`second embodiment will be used to denote like features in
`the third embodiment.
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`The humidifier 90 has a water storage tank 92 positioned
`above the humidifier interior 66. A duct 94 allows water to
`
`flow from the tank 92 into the bottom of the interior 66 up
`to a maximum level indicated by dashed line 96. An addi-
`tional advantage of this embodiment is that it can store a
`relatively large volume of water, to give a longer operational
`time between refilling, but it has a smaller volume of water
`adjacent the heating element, which reduces heating time
`and energy consumption.
`FIG. 12 shows a fourth embodiment of the humidifier 100
`
`according to the invention. Like reference numerals to those
`used in describing the second and third embodiments will
`again be idled to denote like features.
`The humidifier 100 is similar to the humidifier 40 shown
`
`in FIGS. 2 to 8 except it has a flow dividing plate 101 that
`includes four baffles 102. The bafiles 102 cause the supplied
`gas to undertake a longer path between the humidifier inlet
`48 and the outlet 50. An additional advantage of this
`embodiment is that it improves humidification by ensuring
`the supplied gas does not only flow over the portion of the
`water directly between the inlet 48 and outlet 50. A similar
`plate 101 is shown in FIG. 13, except that it includes eight
`of the baflles 102.
`In the embodiments shown in FIGS. 12 and 13 the
`
`in other
`position of the baflles 102 are fixed. However,
`embodiments (not shown) the position of the baflles can be
`adjusted and/or individual baifles can be removed.
`FIG. 14 shows an embodiment of a heating element
`assembly 110 also suitable for use with humidifiers. The
`assembly 110 includes a heating element 112, which is
`similar to that shown in FIG. 9, and a heating plate 114. In
`use, the plate 114 is positioned between the upper surface of
`the heating element 112 and the lower surface or underside
`of a humidifier. The heating plate 114 is separated from a
`base 116 by springs 118.
`When a humidifier filled with a predetermined volume
`(and thus weight) of water is placed on the heating plate 114,
`it compresses the springs 118 such that the plate 114 makes
`contact with the heating element 112 for heating. If there is
`insufficient water in the humidifier, or if the humidifier is
`removed from the assembly 110, the springs 118 lift the
`heating plate 114 away from the heating element 112. This
`creates an air gap 119 between the heating element 112 and
`the hot plate 114 which advantageously reduces further
`heating of the heating plate 114. This reduces the risk of the
`assembly 110 burning a user or starting a fire or the like if
`operated incorrectly.
`FIG. 15 shows a humidifier 120 according to a sixth
`embodiment of the invention and like reference numerals
`
`will again be used to denote like features to earlier embodi-
`ments. The humidifier 120 is similar to the humidifier 90
`
`shown in FIG. 11 in that it has a water storage tank 92
`mounted above the humidification interior 66. However, in
`this embodiment, the flow dividing plate 62 pivots at one
`end about axis 122, as indicated by arrow 123, between
`maximum and minimum humidification positions. The
`humidifier 120 also includes a plug 124 to allow filling of the
`water storage tank 92. The humidifier 120 is shown mounted
`above a heating element assembly 126 which comprises a
`heating element 128 within an outer casing 129.
`FIGS. 16 and 17 show a seventh embodiment of a
`humidifier 130 similar to the embodiment shown in FIG. 15.
`
`However, in this embodiment, the flow dividing plate 62
`rotates about a substantially central axis 132 between the
`maximum humidification position shown in FIG. 16 and the
`minimum humidification position shown in FIG. 17. The
`
`Apex Medical Corp.
`Exhibit 1005
`
`Apex Medical Corp.
`Exhibit 1005
`
`

`
`US 6,554,260 B1
`
`7
`path taken by the supplied gas from the inlet 48 to the outlet
`50 is indicated by arrows 134. The water level is indicated
`by broken line 136.
`FIG. 18 shows another embodiment of a heating element
`assembly 140 similar to that shown in FIG. 14. The assem-
`bly 140 includes a heating element 142, which is similar to
`that shown in FIG. 10, a conducting plate 144 and a heating
`plate 146. The heating plate 146 is separated from a base 148
`by springs 150. The assembly 140 functions similar to the
`assembly 110 shown in FIG. 13.
`Another advantage of the preferred embodiments of the
`invention stems from the ability to control humidification
`levels substantially independently of temperature. Different
`temperatures inhibit the growth of, or kill, different bacteria.
`For example, in chlorinated drinking water (0.2 mg/L) with
`a pH of 7.6, a temperature of 32 degrees C. will kill 99.9%
`of Legionella pneumophilia in 30 minutes (VanDemark &
`Batzing (1987), The Microbes, Benjamin/Cummings Pub-
`lishing Company,
`Inc.). Accordingly, once a particular
`desired temperature has been identified, for example to
`effect a particular bacteria, a heating element can be manu-
`factured to achieve that temperature. The desired effect will
`be achieved whenever the humidifier is operated with that
`element. The desired amount of humidification can be
`
`selected by adjusting the position of the flow dividing plate.
`In contrast, with a thermostatically controlled humidifier,
`the above effect on bacteria could only be achieved by
`setting a minimum temperature in the thermostat. However,
`in the absence of other means to control the humidity, this
`limits the available range of humidification, For example if
`the temperature could not be reduced below 40 degrees C.,
`then a low range of humidification could not be achieved,
`unlike embodiments of the present invention.
`Although the invention has been described with reference
`to specific examples, it is appreciated by those skilled in the
`art that the invention may be embodied in many other forms.
`We claim:
`
`1. A humidifier for use with a breathable gas supply
`apparatus, said humidifier comprising:
`a hollow body adapted for partial filling with water to a
`predetermined maximum water level;
`a gas inlet to the body above the maximum water level;
`a gas outlet from the body above the maximum water
`level;
`a constant temperature heating element to heat the water
`in the body; and
`an adjustable flow divider adapted to divide the interior of
`the body above the maximum water level into a rela-
`tively dry gas region and a relatively wet gas region.
`2. The humidifier as claimed in claim 1, wherein the
`position of the divider is variable between a first position in
`which all of the gas is diverted to the relatively wet gas
`region for maximum humidification, and a second position
`in which all of the gas is diverted to the relatively dry gas
`region for minimum humidification.
`3. The humidifier as claimed in claim 2, wherein the
`divider includes a first end remote the gas inlet and the gas
`outlet and a second end adjacent the gas inlet and the gas
`outlet, wherein the divider is adapted to rotate about or near
`the first end to cause the second end to move between the
`
`first and second positions.
`4. The humidifier as claimed in claim 2, wherein the
`divider includes a first and second end adjacent the gas inlet
`and the gas outlet, wherein the divider is adapted to rotate
`about or near its centre to cause the first and second ends to
`
`move between the first and second positions.
`
`10
`
`15
`
`20
`
`25
`
`30
`
`35
`
`40
`
`45
`
`50
`
`55
`
`60
`
`65
`
`8
`5. The humidifier as claimed in claim 1, wherein the
`constant temperature heating element is a self regulating
`wire.
`6. The humidifier as claimed in claim 1, wherein the
`humidifier includes a storage reservoir adapted to replenish
`the water in the body.
`7. The humidifier as claimed in claim 1, wherein the
`divider includes baffle plates.
`8. The humidifier as claimed in claim 7, wherein the
`position of the baffle plates are fixed.
`9. The humidifier as claimed in claim 7, wherein the
`position of the baffle plates are adjustable.
`10. The humidifier as claimed in claim 1, wherein the
`position of the divider is variable so as to vary the relative
`proportion of the gas flowing from the inlet to the outlet that
`passes through the relatively dry and relatively wet gas
`regions.
`11. A humidifier for use with a breathable gas supply
`apparatus, said humidifier comprising:
`a hollow body adapted for partial filling with water to a
`predetermined maximum water level;
`a gas inlet to the body above the maximum water level;
`a gas outlet from the body above the maximum water
`level;
`a heater to heat the water in the body; and
`an adjustable flow divider adapted to divide the interior of
`the body above the maximum water level into a rela-
`tively dry gas region and a relatively wet gas region,
`wherein the position of the divider is variable so as to
`vary the relatively dry and relatively wet gas regions to
`thereby vary the amount of humidification thereof,
`wherein
`the position of the divider is variable between a first
`position in which all of the gas is diverted to the
`relatively wet gas region for maximum
`humidification, and a second position in which all of
`the gas is diverted to the relatively dry gas region for
`minimum humidification; and
`the divider is a generally planar plate of substantially
`complimentary cross section to the interior of the
`body above maximum water level.
`12. The humidifier as claimed in claim 11, wherein the
`plate includes a threaded hole adapted to engage a threaded
`rod, wherein rotation of the rod causes the plate to move
`between the first and second positions.
`13. The humidifier as claimed in claim 12, wherein the
`exterior of the plate forms a substantially fluid-tight seal
`with the interior of the body.
`14. A humidifier for use with a breathable gas supply
`apparatus, said humidifier comprising:
`a hollow body adapted for partial filling with water to a
`predetermined maximum water level;
`a gas inlet to the body above maximum water level;
`a gas outlet from the body above the maximum water
`level;
`a constant temperature heating element for heating the
`water; and
`an adjustable flow divider adapted to divide the interior of
`the body above the maximum water level into a rela-
`tively dry gas region and a relatively wet gas region,
`wherein the position of the divider is variable so as to
`vary the relative portion of the gas flowing from the
`inlet to the outlet that passes though the relatively dry
`and relatively wet gas regions to thereby vary the
`amount of humidification thereof.
`
`Apex Medical Corp.
`Exhibit 1005
`
`Apex Medical Corp.
`Exhibit 1005