United States Patent
`
`[19]
`
`[11] Patent Number:
`
`4,676,237
`
`Wood et al.
`
`[45] Date of Patent:
`
`Jun. 30, 1987
`
`INHALER DEVICE
`
`[54]
`
`[75]
`
`Inventors:
`
`John D. Wood, Cambridge; Julian
`M. Coles, Elsworth; William R. S.
`Baxter, Cambridge, all of England
`Boutade Worldwide Investments NV,
`Netherlands Antilles
`
`[73] Assignee:
`
`[21] Appl. No.: 321,597
`
`[22] Filed:
`
`Jan. 23, 1986
`
`Foreign Application Priority Data
`[30]
`Jan. 29, 1985 [ZA]
`South Africa ....................... 85/0679
`
`Int. c1.4 ........................................... .. A61M 15/00
`[51]
`[52] U.S. Cl. ........................ .. 128/203.17; 128/204.13;
`128/204.14
`
`[58] Field of Search .................... .. 128/203.17, 203.27,
`128/204.13, 200.18, 200.21, 200.14; 261/104,
`142, 153, 107, 154, DIG. 65, 78 A; 219/274,
`272, 362; 122/366
`
`[56]
`
`References Cited
`U.S. PATENT DOCUMENTS
`
`3,431,393 3/ 1969 Katsuda ............................ .. 219/274
`4,110,419
`8/1978 Miller
`128/204.13
`
`. 261/DIG. 65
`4,263,907
`4/1981 Lindsey
`
`4,419,302 12/1983 Nishino et al.
`.
`128/204.13
`4,564,748
`1/1986 Gupton .......................... 128/203.27
`
`FOREIGN PATENT DOCUMENTS
`
`.. .. .. 219/274
`
`......... .. 128/203.27
`
`9/1982 Japan .. .. .. .. . .. .. .
`0043041
`1294808 11/1972 United Kingdo
`
`Primary Examiner-—Henry J. Recla
`Attorney, Agent, or Firm—McGlew and Tuttle
`
`ABSTRACT
`[57]
`An inhaler device which includes a wick which draws
`water from a reservoir and which is in contact with a
`heated plate. Air is directed over the heated wick sur-
`face by means of a fan thereby to produce a stream of
`heated humid air. A sensor monitors the temperature of
`the heated air stream and a control circuit which is
`responsive to the sensor maintains this temperature
`substantially constant at a predetermined value. The
`heated humid air stream is available for inhalation by a
`patient for the treatment of certain ailments.
`
`1,688,200 10/1928 Morgenthaler ..................... 219/274
`
`7 Claims, 4 Drawing Figures
`
`
`
`NU MARK Ex.1015 p.1
`
`

`

`U.S. Patent
`
`Jun. 30,1987
`
`Sheet] of4
`
`4,676,237
`
`NU MARK Ex.1015 p.2
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`

`

`U.S. Patenf
`
`Jun. 30,1987
`
`Sheet2 of4
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`4,676,237
`
`
`
` ,7./.
`
`“\:&
`
`NU MARK Ex.1015 p.3
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`
`

`

`U. S. Patent
`
`Jun. 30,1987
`
`Sheet3 of4
`
`4,676,237
`
`NU MARK Ex.1015 p.4
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`

`

`U.S. Patent
`
`Jun. 30,1987
`
`Sheet4 or4
`
`4,676,237
`
`j
`
`30
`
`NU MARK Ex.1015 p.5
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`
`

`

`1
`
`INHALER DEVICE
`
`4,676,237
`
`BACKGROUND OF THE INVENTION
`This invention relates to an inhaler device.
`It has been proposed to treat ailments such as the
`common cold by causing a patient to inhale heated
`humid air. It has been established through experimenta-
`tion that the air temperature must be accurately con-
`trolled at a value of approximately 43° C. and that the
`relative humidity of the air should be at, or close to,
`saturation.
`
`A large number of devices have previously been
`proposed for providing such a stream of air. Examples
`of these devices are disclosed in the specifications of the
`following patents: German Pat. Nos. 102693, 306287,
`501505, 556493, 62252, 1233981, 1148355, 1933350,
`2020435, 2160561, 2942631, 30259361 and 3139135;
`French Pat. Nos 727129, 783708, 914188, 2270897,
`2276840, and 2440742; British Pat. Nos. 197946, 421708.
`1435520, 1475710, 1490974, 1448473, 1343385, 1294808,
`1242694, 1107780, 2010097A and 200238A; U.S. Pat.
`Nos.
`631,575, 742,244,
`865,021, 929,199,
`155,419,
`1,832,916, 2,040,630, 2,906,463, 2,151,719, 2,168,450,
`2,174,531, 2,230,265, 2,233,431, 2,241,356, 2,262,711,
`2,283,952, 2,366,753, 2,387,917, 2,445,347, 2,709,577,
`3,190,502, 3,434,471, 3,506,003, 3,903,883, 3,990,441,
`4,023,718 and 4,369,777; European Pat. No. 0.011847;
`Swiss Pat. No. 261779 and Austrian Pat. No. 150117.
`
`SUMMARY OF THE INVENTION
`
`It is an object of the present invention to provide an
`inhaler device for generating a stream of air at a prede-
`termined temperature and relative humidity level which
`is lightweight and relatively easy to manufacture and
`which offers a high degree of safety in its use.
`The invention provides an inhaler device which in-
`cludes a housing which is formed with an air passage, a
`water reservoir, heater means, wick means which in-
`cludes a section which extends into the water in the
`reservoir and a portion which is in heat exchanging
`contact with the heater means, means for directing an
`air stream through the air passage past the said portion
`of the wick means thereby to entrain moisture in the air
`stream and to heat the air stream, first means for sensing
`the temperature of the air stream at a given location
`which is downstream of the said portion of the wick
`means, and means responsive to the first temperature
`sensing means for varying the operation of the heater
`means thereby to maintain the temperature of the air
`stream, at the given location, substantially at a predeter-
`mined value.
`The said portion of the wick means may be supported
`on a first side by means of a plurality of spaced forma-
`tions and a second side of the said portion of the wick
`means may be in contact with an opposing surface of
`the heater means, the air stream being directed past the
`first side of the said portion of the wick means. Apart
`from not materially affecting the free flow of the air
`stream the formations provide a wick support that
`makes it possible to have a convenient detachable wick-
`ing system. These are significant advantages.
`This arrangement means that the wick means, which
`is saturated with water, is heated by being in direct
`contact with the heater means and the water vapour
`which is released into the air stream is heated. The air
`stream is thus heated only by picking up hot water
`vapour and steam from the wick. The relative humidity
`
`10
`
`20
`
`25
`
`30
`
`35
`
`45
`
`50
`
`55
`
`65
`
`2
`in the air stream is therefore approximately 100%. Heat-
`ing of the air stream directly by the heater is to be
`avoided, for the heat is “dry”, and reduces the humidity
`level.
`
`In a preferred form of the invention the reservoir is
`located at a lower end of the housing and the said por-
`tion of the wick means is positioned above the reservoir
`and below the heater means. However it is possible in
`variations of the invention to direct the air stream over
`an upper surface of a saturated wick. In a preferred
`variation substantially the whole of the heater means is
`covered by the wick means. Practically all of the heat is
`then taken up by the wick means, insulation require-
`ments are reduced, and the heater can be smaller. The
`emission of “dry heat” into the air stream is also dimin-
`ished.
`The reservoir is preferably detachably engageable
`with the housing. The reservoir may be provided as a
`sealed unit, which contains distilled or demineralised
`water. A seal is removed from the reservoir by a user
`and the reservoir is then engaged with the housing so
`that the device is ready for use. In this variation of the
`invention the reservoir preferably includes a container,
`water in the container, support means above the water,
`wick means which includes a portion which is sup-
`ported by the support means and a section which ex-
`tends into the water in the reservoir, and detachable
`means overlying the wick means and sealing the con-
`tainer.
`The heater means preferably includes a heating ele-
`ment and the means for varying the operation of the
`heater means includes switching means which controls
`the connection of the heating element to a source of
`electrical power in response to the first temperature
`sensing ‘means.
`A second temperature sensing means may be used for
`detecting a rise in the temperature of the air stream, at
`the given location, above an upper limit.
`The depletion of water in the reservoir may be de-
`tected by means of a third temperature sensing means
`which is in contact with the heater means. When the
`water supply is exhausted the wick means is dried and
`no longer exerts a cooling action on the heater means.
`Consequently the temperature of the heater means rises
`and this can be detected by means of a suitable sensor.
`Similarly the sensor detects an attempt to operate the
`device when the resevoir is not in place.
`The invention also extends to a method of providing
`a stream of heated humid air which includes the steps of
`heating at least a portion of a saturated wick, directing
`an air stream past the heated wick portion thereby to
`entrain moisture into the air stream, and to heat the air
`stream, sensing the temperature of the air stream down-
`stream of the heated wick portion, and controlling the
`heating of the wick portion in response to the sensed
`temperature.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`The invention is further described by way of example
`with reference to the accompanying drawings in which:
`FIG. 1 is a sectional side elevation of an inhaler de-
`vice according to the invention,
`FIG. 2 is a view from the rear of the interior of the
`device shown in FIG. 1 with a reservoir, detached from
`an upper portion of the device, shown in section,
`FIG. 3 illustrates one way in which the device of
`FIGS. 1 and 2 is used, and
`
`NU MARK Ex.1015 p.6
`
`
`

`

`3
`FIG. 4 is a diagram of a circuit used for controlling
`the operation of the device shown in FIGS. 1 and 2.
`DESCRIPTION OF PREFERRED EMBODIMENT
`FIGS. 1 and 2 illustrate an inhaler device 10 accord-
`ing to the invention. The device includes a housing 12
`and a detachable reservoir 14 which is engageable with
`a lower end of the housing. The housing 12 is made
`from four components and includes a fan cover 16, a
`front section 18, a rear section 20, and a rear cover 22.
`The cover 22 has a mounting clip 24 projecting from it.
`The front and rear sections 18 and 20 form an electron-
`ics compartment 25 between them.
`The fan cover 16 has a partially shrouded air inlet
`opening 26 formed through it. A fan 28 which is driven
`by means of a motor 30 is mounted inside the housing so
`as to draw air through the opening 26 and expel
`it
`downwardly through an air passage 32 in the direction
`indicated by means of arrows 34. The fan operates cen-
`trifugally and creates an air flow of approximately 45
`litres per minute through the air passage.
`Mounted below the motor 30 and extending across
`the interior of the housing is a heating arrangement 36.
`This includes a ceramic heater plate 38 which is formed
`from 2 mm thick alumina with a heating element 40
`being provided by a pattern printed in resistive ink on
`its upper surface. Terminals 42 which are connected to
`the heating element project upwardly into the electron-
`ics compartment inside the housing, see FIG. 2. One of
`these terminals is connected to a current fuse 44. The
`device in addition includes a thermal fuse, not shown,
`which provides protection in the event of normal con-
`trol of the heating element being lost due to a faulty
`condition. The thermal fuse is mounted within the-
`heater assembly 36, between the heater plate 38 and an
`insulating layer 46 of ceramic fibre which is 5 mm thick
`and which overlies the heater plate 38. This fuse is
`responsive to the temperature of the heater plate and it
`interrupts the supply to the heater element, in the event
`of a malfunction, if the temperature of the heater rises
`._ above a predetermined value.
`The heater plate 38 and the insulating layer 46 are
`enclosed in a box 48 which is moulded in a heat resistant
`compound, to form a waterproof casing for the heating
`arrangement. The moulding includes projections 50
`which engage with the housing thereby to retain the
`heating arrangement in position in the housing. The
`heater is also insulated on the air passage side to reduce
`the transfer of “dry heat” into the air stream.
`A thin aluminium plate 52 is positioned between the
`heating arrangement and the electronics compartment
`25. A portion of the plate, see FIG. 1, protrudes into the
`air passage 32 and thereby acts as a heat sink on the
`upstream side of the air passage relatively to the heating
`arrangement. This reduces the unwanted transfer of 55
`heat into the lower wall of the electronics compart-
`ment.
`
`l0
`
`15
`
`20
`
`25
`
`30
`
`35
`
`45
`
`50
`
`4,676,237
`
`4
`passage 32 adjacent the rear cover 22 of the device. The
`thermistor 62 is referred to as the main control thermis-
`tor and this determines, via the electronic circuit shown
`in FIG. 4, how much power is applied to the heater so
`as to achieve a desired operating condition. The second
`thermistor 64 is fitted for safety reasons and it detects an
`excess rise in air temperature in the passage 32. In the
`event of the air temperature increasing to an undesirable
`limit a warning buzzer 66, see FIG. 2, is activated. The
`thermistors are sealed on the printed circuit board 56 by
`means of a sealing compound 68.
`The air passage on the rear side of the device termi-
`nates in an exit 70 which is substantially horizontal.
`The reservoir 14 includes a container 72 with an
`upper moulding 74 which acts as a support for a wick
`76. The support 74 includes a number of upstanding
`projections 78 which are spaced apart and which
`contact a lower surface of the wick thereby supporting
`the wick substantially horizontally. The support 74
`includes a central downwardly extending projection 80
`which is slotted and which engages with a central por-
`tion of the wick thereby enabling this central wick por-
`tion to extend to the bottom of the container 72.
`The reservoir is intended to be disposable and it is
`supplied with approximately 70 ml of demineralised or
`distilled water 82. The wick takes up moisture from the
`water by capillary action. The wick is made from a
`non-woven viscose rayon.
`The reservoir 14 is sealed by means of a foil cover 84
`(shown chain dotted) which is attached to a lower pe-
`rimeter of the support 74 and which is close fitting over
`the wick. This cover protects the wick prior to usage of
`the reservoir and ensures that water is not spilt from the
`container. The cover is removed before the reservoir is
`engaged with the upper portion of the inhaler device.
`The water in the reservoir is sterilised by gamma radia-
`tion.
`The wick support 74 has vents 86 so positioned that
`spillage is avoided, when the container is full, if the
`container is tilted by up to 20° from the vertical.
`When the reservoir 14 is engaged with the housing 12
`a seal 88 prevents spillage of the water externally and
`also acts as an air seal.
`FIG. 3 illustrates the device 10 in use. A power sup-
`ply cord 90 is connected to the socket 58 on the hous-
`ing. A strap 92 is engaged in a suitable way with the
`mounting clip 24, shown in FIG. 1, on the rear cover of
`the housing. The strap passes around the neck of a user.
`A flexible tube 94 is connected to the exit 70 from the air
`passage 32 and terminates in an adaptor piece 96 which
`diverts the air stream through 90° to allow it to impinge
`evenly on the nostrils of the user. The adaptor clips on
`to a mask 98 which is held in position over the nose of
`the user by means of an elastic strap 100 which is fixed
`to an aluminium strip 102 on the mask.
`The operation of the inhaler device is under the con-
`trol of the circuit shown in FIG. 4 which, as has previ-
`ously been mentioned, is mounted on the printed circuit
`board 56in the electronics compartment of the housing
`12. The output from the transformer 54 is rectified by a
`bridge rectifier 104 and applied to the motor 30 and to
`a simple voltage smoothing circuit, not shown. The
`output of the smoothing circuit powers a thermistor
`monitoring circuit 105. A switching circuit 107 is used
`for controlling the supply of electrical power to the
`heater element 40.
`The circuit 105 shows the main thermistor 62, the
`safety or second thermistor 64 and the buzzer 66. The
`
`The electronics compartment includes a transformer
`54 which is mounted on a printed circuit board 56 and
`which operates from a mains supply. The transformer
`provides power for the control circuit shown in FIG. 4.
`The mains supply is connected to a socket 58 which is
`internally wired via an on/off switch 60, the fuse 44 and
`the thermal fuse to the heating element 40, and to the
`electronic circuitry which is mounted on the printed
`circuit board 56.
`Two encapsulated thermistors 62 and 64 respectively
`extend from the printed circuit board 56 into_ the air
`
`65
`
`NU MARK Ex.1015 p.7
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`

`4,676,237
`
`6
`
`5
`circuit illustrates a third thermistor 106 which is not
`visible in FIGS. 1 and 2. This thermistor is a small chip
`which is attached to the upper surface of the ceramic
`heater plate 38 and which therefore monitors the tem-
`perature of this plate. The chip is of course electrically
`insulated from the heating element.
`All the components shown in the circuit will not be
`described in detail for the nature of these components,
`and their method of operation,
`is apparent to those
`skilled in the art. However the aspects of the circuit
`which are essential for an understanding of the working
`of the inhaler device of the invention will be further
`elaborated on.
`
`then the comparator 112
`passage 32 reaches 46" C.
`switches and the buzzer is again sounded.
`It should be mentioned that
`the triangular wave
`which is applied to the reference input to the compara-
`tor 112 is produced by an oscillator 126 which functions
`at 1 Hz. This oscillator is also used to gate the buzzer 66
`via an OR gate 128.
`The triac 116 is driven by a transistor circuit 130. The
`main supply line is connected to terminals 132 and 134
`in series with the heater and the triac.
`The driver 130 includes transistors 136, 138, 140 and
`142. The collector currents of the transistors 136 and
`138 only drop to zero at zero crossings of the supply
`voltage. The transistors 140 and 142 then drive the triac.
`The triac has zero crossing triggering to keep radio
`interference to a minimum.
`As indicated on/off switching of the triac is initiated
`via the opto-isolator 118. This increases the safety inher-
`ent in the circuit.
`As a final feature of the circuit shown in FIG. 4 it
`should be pointed out that the speed of the motor 30 can
`be adjusted by means of a series resistor 144 to ensure
`that the correct rate of air flow is provided by the fan
`28.
`As has previously been indicated the inhaler device
`of the invention is intended to provide an air flow of
`approximately 45 litres per minute of heated humid air.
`The relative humidity of the air should be in excess of
`70% and the temperature of the air should be accurately
`controlled at a value of approximately 43° C. The de-
`vice functions as follows.
`Air is drawn into the passage 32 by means of the fan
`28 which is rotated by the motor 30. The air is directed
`downwardly in the passage 32 and passes below the
`undersurface of the wick 76 between the spaced projec-
`tions 78. The air then travels upwardly past the thermis-
`tors 62 and 64 and leaves the housing via the air tube 94.
`The air is then presented to the user's nostrils where it
`is inhaled.
`The wick 76 is kept in close contact with the heater
`plate 38 by the physical engagement of the housing and
`the reservoir. The wick is saturated at all times with
`water which is taken up by capillary action from the
`reservoir. As the wick is heated water vapour is given
`off into the volume between the wick support plate 74
`and the wick and it is through this volume that the air
`passes. The air stream therefore entrains with it heated
`water vapour and is at the same time heated by coming
`into contact with the heater plate 38. The arrangement
`is such that the relative humidity of the air stream is
`considerably in excess of 70%.
`The temperature of the air is monitored by the main
`thermistor 62 prior to leaving the housing 12. The con-
`trol function provided by the circuit in response to the
`temperature which is sensed by the thermistor 62 is not
`a simple on/off operation responding to an air tempera-
`ture above or below a set point. This approach does not
`provide the necessary accuracy and stability and conse-
`quently a proportional control technique is used. This
`works as follows. Around the desired temperature, say
`43° C., there is a small temperature band referred to as
`a proportional band. When the temperature of the air is,
`say, halfway in this band the controller allows half the
`full power to flow, by letting half the AC main cycles
`through in a given time interval. The proportion of full
`power applied to the heater depends linearly on the air
`temperature within the proportional band, varying from
`zero when the air temperature is at the upper end of the
`
`10
`
`15
`
`25
`
`30
`
`35
`
`The stabilising circuit produces a voltage V“ which
`is applied to a reference circuit 108 which produces a
`reference voltage of V“/2 for all the control circuits.
`The thermistor 62 is connected to a main control
`comparator 110. The thermistors 64 and 106 are simi-
`larly connected to comparators 112 and 114 respec-
`f20
`tively. The reference voltage V“/2 is applied to each o
`the comparators 110, 112 and 114.
`The reference voltage to the main comparator 110
`has a superimposed triangular wave with an amplitude
`which corresponds to a temperature variation of 3° C.
`This provides a proportional band in the control loop
`and gives an optimum transient response so that the
`operating temperature is reached as quickly as possible.
`The heating element 40 is controlled via a triac 116 by
`the “burst fire” method. The triac, and hence the heater,
`is switched at a 1 Hz rate with a varying duty cycle
`depending on the power demand.
`The heating element is controlled by the comparator
`110 via an opto-isolator 11811 and 118b. As indicated the
`reference voltage to the comparator 110 is a small am-
`plitude triangular wave which is centered on the refer-
`ence voltage V“/2. The other input to the comparator
`is a voltage derived from a potential divider formed by
`the thermistor 62 and resistors 120 and 122. The resistor
`120 is variable and is set to provide the desired control
`temperature to which the air must be heated.
`As the temperature of the thermistor 62 increases so
`does the voltage at the positive input to the comparator
`110. Thus the duty cycle of the heating element, which
`is controlled by the output voltage of the comparator
`varies. Since this system is a feedback loop the circuit
`operates to maintain the thermistor at the resistance
`required for a duty cycle of about 60% and in this way
`the temperature is precisely controlled.
`The comparator 110 is provided with a small amount
`of hysteresis to ensure clean switching of the compara-
`tor.
`
`45
`
`50
`
`The heating element 40 is protected by means of the
`thermal fuse previously referred to. This fuse open
`circuits if the heater temperature rises excessively. Ad-
`ditional protection is provided for the heater, in the
`event of the reservoir 14 being depleted of water, by the
`thermistor 106 which is fixed to the heater. This therm-
`istor controls the comparator 114 and if the temperature
`sensed by this thermistor rises above 140° C. the com-
`parator switches so as to turn off the triac via the opto-
`isolator 118 and to turn on the buzzer 66 via an OR gate
`124.
`
`55
`
`The comparator 114 has a large amount of hysteresis
`and consequently the heater has to cool considerably
`before it can again be turned on.
`The thermistor 64 is designed to detect an excessive
`rise in the air temperature. If the air temperature in the
`
`65
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`NU MARK Ex.1015 p.8
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`

`7
`temperature band to 100% when the air temperature is
`at the lower end of the band.
`The heater element is controlled in this way so as to
`maintain the air temperature at the outlet at 43° C.i-0.5°
`C.
`
`The temperature band is however not centred on 43°
`C. because
`(a) the desired air temperature is reached typically
`when about three quarters of the full power is
`applied, and
`(b) the desired air temperature is 43° C., measured at
`the outlet, and there is a small temperature drop in
`the air as it travels along the tube 94 to the mask 96.
`If the air temperature rises, because of a malfunction,
`to 46° C. this is sensed by the second or safety thermis-
`tor 64 and the buzzer 66 is sounded as a warning to the
`user.
`
`If the water 82 in the reservoir 40 is depleted then the
`temperature of the heater plate rises as it is no longer
`subjected to the cooling effect of the wet wick. The
`thermistor 106 monitors the temperature of the heater
`plate and if this rises above 140° C., indicating that the
`water supply is exhausted, the buzzer 66 is sounded and
`the triac 116 is turned off in a manner analogous to that
`already described. Similar action occurs if the device is
`turned on when the reservoir is not coupled to the hous-
`mg.
`The close contact of the saturated wick portion with
`the heater plate provides a highly efficient way of rais-
`ing the humidity level of the air stream and of simulta-
`neously heating the air stream. The‘ air stream should
`not be directly heated by the heater plate for this heat is
`dry and reduces the humidity level. It is to be noted that
`the wick presents a large area to the air stream, and the
`depth of the volume of space for the air flow is rela-
`tively small, and consequently the air stream is heated,
`and takes up moisture, substantially uniformly.
`The circuit shown in FIG. 4 thus provides a control
`function to ensure that the temperature is kept constant
`at a desired value and in addition provides a monitoring
`function which advises the user when the water supply
`is exhausted or when the heater temperature increases
`excessively.
`The device has being shown in FIG. 3 as providing
`an air stream for inhalation through the nose of a user.
`Clearly this system could be adapted to provide a
`mouth piece for oral inhalation.
`The device of the invention is lightweight and easy to
`construct and use and offers a high degree of safety
`while at the same time providing an air stream of prede-
`termined characteristics.
`Various modifications can be made to the device
`without departing from the scope of this specification.
`For example the heating element could comprise a
`metal sheathed element with a heater core wire wound
`on mica. The socket 58 can be dispensed with and be
`replaced by a normal mains entry cable with a sheath.
`The exit 70 from the air passage could be at any other
`suitable orientation, for example vertical, to provide an
`appropriate connection point for the tube 94.
`We claim:
`1. An inhaler device which comprises
`a housing which is formed with an inlet and an outlet
`with an air passage therebetween, said housing
`having an open lower end,
`a water reservoir which is detachably engaged with
`the housing at the lower end thereof and which
`includes an upwardly facing cover which extends
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`4,676,237
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`8
`over the reservoir to cover water which may be
`filled into the reservoir and which has a plurality of
`spaced formations which extend upwardly from
`the cover to define air flow channels,
`heater means which includes a heater plate mounted
`in said housing adjacent the open lower end with a
`substantially flat and downwardly facing surface
`which opposes the cover of the water reservoir,
`wick means which includes a section which extends
`into the reservoir to be saturated with water in the
`
`reservoir and a portion having a downwardly fac-
`ing first side and an upwardly facing second side
`and which is supported on the downwardly facing
`first side on the plurality of spaced formations
`which extend upwardly from the cover and with
`the upwardly facing second side in heat exchang-
`ing contact with the downwardly facing surface of
`the heater means,
`fan means mounted to the housing adjacent said inlet
`and means in said housing together with said fan
`means for directing an air stream into the housing
`inlet through the air passage and air flow channels
`defined by the downwardly facing first side of said
`portion of the wick means and above the cover of
`the water reservoir thereby to entrain moisture in
`the air stream and to heat the air stream and further
`to the housing outlet,
`first means for sensing the temperature of the air
`stream at a given location in said air passage which
`is downstream of said portion of the wick means,
`means responsive to the first temperature sensing
`means for varying the operation of the heater
`means thereby to maintain the temperature of the
`air stream, at a given location, substantially at a
`predetermined value, and
`means connected to the outlet of the air passage for
`conveying the heated and humidified air stream to
`the respiratory system of user.
`2. Device of claim 1, wherein the heater means in-
`cludes a heating element which is in oirect thermal
`contact with the heater plate, and the means for varying
`the operation of the heater means includes switching
`means which controls the connection of the heating
`element to a source of electrical power in response to
`the first temperature sensing means.
`3. A device according to claim 1 which includes a
`second temperature sensing means for detecting a rise in
`the temperature of the air stream, at the given location,
`above an upper limit.
`4. A device according to claim 1 which includes a
`third temperature sensing means, in contact with the
`heater means, for detecting when the water in the reser-
`voir is depleted.
`5. A disposable reservoir for use in a device intended
`for supplying temperature controlled, heated and hu-
`midified air, which comprises
`a sealable container providing a water-receiving
`space and having an open upper end adapted to be
`detachably engaged with a lower open end of a
`housing of such a device,
`support means forming a cover adjacent the upper
`end of the container and extending over the water-
`receiving space,
`a plurality of spaced formations extending upwardly
`from a portion of the cover defining air flow chan-
`nels,
`wick means including a section which extends into
`the water-receiving space and a portion having a
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`NU MARK Ex.1015 p.9
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`4,676,237
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`means and the portion of the cover at which the spaced
`formations are located and sealing the container at the
`open upper end thereof‘.
`7. Reservoir of claim 6, wherein the so-sealed con-
`tainer is in sterilized condition.
`*
`*
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`“
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`9
`downwardly facing first side which is supported on
`the plurality of spaced formations to define air flow
`passages therethrough and an upwardly facing
`second side at the open upper end of the container.
`6. Reservoir of claim 5 including water in the receiv-
`ing space, and detachable means overlying the wick
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`NU MARK Ex.1015 p.10
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