Patent Publication Number: US-2022235952-A1

Title: Humidifier

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This is a continuation of International Application No. PCT/JP2020/033979 filed on Sep. 8, 2020, which claims priority from Japanese Patent Application No. 2019-190177 filed on Oct. 17, 2019. The contents of these applications are incorporated herein by reference in their entireties. 
    
    
     BACKGROUND 
     Technical Field 
     The present disclosure relates to a humidifier. 
     A respirator described in Patent Document 1 is provided with a blower and a humidifier. In this respirator, air force-fed from the blower enters the humidifier, and is humidified in the humidifier, and then the humidified air is sent to a patient. The humidifier is provided with a housing case in which a housing space is defined, a water storage tank housed in the housing space of the housing case, and a heater for vaporizing water stored in the tank. The tank is configured to contain water for humidifying the inside of the humidifier. Further, the tank can be taken in and out of the housing case.
     Patent Document 1: Japanese Unexamined Patent Application Publication No. 2017-121502   

     BRIEF SUMMARY 
     In the humidifier described in Patent Document 1, when the tank removed is mounted inside the housing space of the housing case, the tank may be mounted in a state of being displaced with respect to the housing case. In this case, there is a possibility that displacement occurs also in a positional relationship between the tank and the heater, and water stored in the tank cannot be heated by the heater as designed. 
     Solution to Problem 
     In order to solve the above-described problem, an aspect of the present disclosure is a humidifier including a housing case, a water storage tank housed inside the housing case, and a humidification promoting mechanism configured to vaporize water stored in the tank, in which a gas humidified by the humidification promoting mechanism is discharged from the tank, wherein an attachment/detachment port for taking in and out the tank opens in the housing case, a first case hole, in addition to the attachment/detachment port, for causing an inside and an outside of the housing case to communicate with each other opens in the housing case, a first tank hole for causing an inside and an outside of the tank to communicate with each other opens in the tank, a first seal member separating a first gas flow path leading to an inside of the tank through the first case hole and the first tank hole, from an external space of the housing case is arranged between the housing case and the tank, and the first seal member, when viewed from a taking in/out direction of the tank, extends along an inner surface of the housing case, and is arranged so as to sandwich the tank from both sides in one direction orthogonal to the taking in/out direction. 
     According to the above configuration, first, the first seal member prevents a gas flowing through the first gas flow path from leaking outside the housing case. In addition to that, the first seal member is arranged so as to sandwich the tank from both the sides in the one direction, when viewed from the direction in which the tank is taken in and out. Thus, when the tank is housed inside the housing case, the tank is positioned in the one direction by the first seal member. Thus, it is possible to prevent the tank from being displaced in the one direction inside the housing case. 
     In order to solve the above-described problem, an aspect of the present disclosure is a humidifier including a housing case, a water storage tank housed inside the housing case, and a humidification promoting mechanism configured to vaporize water stored in the tank, in which a gas humidified by the humidification promoting mechanism is discharged from the tank, wherein an attachment/detachment port for taking in and out the tank opens in the housing case, a first case hole, in addition to the attachment/detachment port, for causing an inside and an outside of the housing case to communicate with each other opens in the housing case, a tank hole for causing an inside and an outside of the tank to communicate with each other opens in the tank, a first seal member separating a first gas flow path leading to an inside of the tank through the first case hole and the tank hole, from an external space of the housing case is arranged between the housing case and the tank, an elastic member is arranged between the housing case and the tank, and the elastic member, when viewed from a taking in/out direction of the tank, is arranged on a side opposite to the first seal member with the tank interposed therebetween, in one direction orthogonal to the taking in/out direction. 
     According to the above configuration, first, the first seal member prevents a gas flowing through the first gas flow path from leaking outside the housing case. In addition to that, the first seal member and the elastic member are arranged so as to sandwich the tank from both the sides in the one direction, when viewed from the direction in which the tank is taken in and out. Thus, when the tank is housed inside the housing case, the tank is positioned in the one direction by the first seal member and the elastic member. Thus, it is possible to prevent the tank from being displaced in the one direction inside the housing case. 
     It is possible to suppress displacement of a tank with respect to a housing case. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view illustrating a main body unit and a base unit of a CPAP device. 
         FIG. 2  is a perspective view illustrating the main body unit and the base unit of the CPAP device in a first use state. 
         FIG. 3  is an explanatory diagram illustrating a schematic configuration of the CPAP device in the first use state. 
         FIG. 4  is an explanatory diagram illustrating a schematic configuration of the CPAP device in a second use state. 
         FIG. 5  is a perspective view in which the base unit is viewed from an angle different from that of  FIG. 1 . 
         FIG. 6  is an end view of the base unit. 
         FIG. 7  is a schematic view illustrating the first use state of the CPAP device. 
         FIG. 8  is a schematic view illustrating the second use state of the CPAP device. 
         FIG. 9  is an end view of a base unit to be compared. 
         FIG. 10  is an end view of a base unit in a second embodiment. 
         FIG. 11  is an end view of a base unit in a third embodiment. 
         FIG. 12  is an end view of a base unit in a fourth embodiment. 
         FIG. 13  is an end view of a base unit in a modification. 
         FIG. 14  is an end view of a base unit in a modification. 
     
    
    
     DETAILED DESCRIPTION 
     Hereinafter, an embodiment in which a humidifier is applied to a continuous positive airway pressure (CPAP) device will be described with reference to the figures. 
     First Embodiment 
     First, a configuration of a CPAP device that sends air introduced into the device to a user&#39;s respiratory tract will be described. As illustrated in  FIG. 1 , a CPAP device  10  is provided with a main body unit  20  and a base unit  40 . Additionally, as illustrated in  FIG. 3 , the main body unit  20  is provided with a blower  31  as a main constituent element. The base unit  40  is provided with a second silencer  51  and a humidifier  70  as main constituent elements. 
     As illustrated in  FIG. 1  and  FIG. 2 , the main body unit  20  can be attached to and detached from the base unit  40 . In the present embodiment, the CPAP device  10  is configured to be usable in a first use state and a second use state. The first use state is a state in which the main body unit  20  is loaded into the base unit  40  and used, and the second use state is a state in which the main body unit  20  is used without necessarily being loaded into the base unit  40 . In other words, in the first use state, as illustrated in  FIG. 3 , the main body unit  20  and the base unit  40  are used. As illustrated in  FIG. 4 , in the second use state, only the main body unit  20  is used, and the base unit  40  is not used. 
     Next, a configuration of the main body unit  20  will be described. 
     As illustrated in  FIG. 1 , the main body unit  20  is provided with a first housing  21  in a flat rectangular parallelepiped shape. As illustrated in  FIG. 4 , the blower  31  and the like are built inside the first housing  21 . Note that, in the following description, when directions related to the first housing  21  are denoted, as illustrated in  FIG. 1 , a thickness direction of the first housing  21  is defined as a height direction Td. In addition, a long side direction of the first housing  21  is defined as a length direction Ld, and a short side direction is defined as a width direction Wd. 
     As illustrated in  FIG. 1 , an operation unit  22  for operating the main body unit  20  is provided on an upper side surface  21 U of the first housing  21 . In this embodiment, the operation unit  22  is configured with a switch  22 A in a circular shape, and a switch  22 B in an annular shape arranged so as to surround the switch  22 A. Both the switches  22 A and  22 B are push button switches, and operating these switches makes it possible to turn on or off a power supply of the main body unit  20 , change settings, and the like. 
     In a first end surface  21 A which is an end surface on a first end side in the length direction Ld of the first housing  21 , a first introduction port  23  for introducing air from the outside to the inside of the first housing  21  opens. A filter  24  that filters dust and the like contained in the air introduced into the first housing  21  is mounted to the first introduction port  23 . 
     As illustrated in  FIG. 4 , a main flow path  32  through which air flows is defined inside the first housing  21  of the main body unit  20 . In the main body unit  20 , an upstream end of the main flow path  32  is connected to the first introduction port  23 . The blower  31  that sends out air from the first introduction port  23  to a downstream side is mounted in midstream of the main flow path  32 . The blower  31  is, for example, a centrifugal fan. In the main flow path  32 , a first silencer  33  is mounted between the first introduction port  23  and the blower  31 . The first silencer  33  attenuates a flow sound of air that flows through the main flow path  32  along with driving of the blower  31 . 
     A pressure sensor  34  that detects pressure of air downstream of the blower  31  in the main flow path  32  is mounted inside the first housing  21 . Additionally, a flow rate sensor  35  that detects a flow rate of air downstream of the blower  31  in the main flow path  32  is mounted inside the first housing  21 . Further, a temperature sensor  36  that detects a temperature of air flowing through the main flow path  32  is mounted inside the first housing  21 . A first lead-out portion  25  for leading out air from the inside to the outside of the first housing  21  is connected to a downstream end of the main flow path  32 . 
     As illustrated in  FIG. 1 , the first lead-out portion  25  protrudes from the first end surface  21 A of the first housing  21 . The first lead-out portion  25  is arranged so as to be aligned with the first introduction port  23  in the width direction Wd of the first housing  21 . The first lead-out portion  25  has a cylindrical shape as a whole, and protrudes from the first end surface  21 A along the length direction Ld. Then, an internal space of the first lead-out portion  25  communicates with the main flow path  32  inside the first housing  21 . 
     In the first end surface  21 A, a first connector  27  for electrically connecting the main body unit  20  to the base unit  40  is recessed. The first connector  27  is a so-called female connector, and a plurality of terminals is provided therein. The first connector  27  is arranged on a lower side of the first lead-out portion  25 . 
     Next, an electrical configuration of the main body unit  20  of the CPAP device  10  will be described. 
     As illustrated in  FIG. 4 , the main body unit  20  is provided with a first control unit  37  for controlling operation of the blower  31 . Note that, the first control unit  37  is electrically connected to the first connector  27  by wiring (not illustrated). 
     The first control unit  37  may be configured as circuitry including 1) one or more processors that execute various processes in accordance with a computer program (software), 2) one or more dedicated hardware circuits, such as an application-specific integrated circuit (ASIC), that execute at least some processes of the various processes, or 3) a combination thereof. The processor includes a CPU and memories, such as a RAM and a ROM, and the memory stores program codes or directives configured to cause the CPU to execute the processes. The memory or a computer-readable medium includes any available medium that can be accessed from a general purpose or dedicated computer. 
     In the first housing  21  of the main body unit  20 , a battery  38  is provided for supplying power to the blower  31 , the pressure sensor  34 , the flow rate sensor  35 , the temperature sensor  36 , and the first control unit  37 . The battery  38  is a secondary battery that can be repeatedly charged, and is charged by connecting a charging cable (not illustrated) to the main body unit  20 . Further, the battery  38  is also electrically connected to the first connector  27 . 
     The first control unit  37  is inputted with a signal indicating an operation from the operation unit  22 . The first control unit  37  is inputted with a pressure value detected by the pressure sensor  34 . The first control unit  37  is inputted with a flow rate value detected by the flow rate sensor  35 . The first control unit  37  is inputted with a temperature value detected by the temperature sensor  36 . The first control unit  37  is configured to, based on these values inputted, increase or decrease the number of rotations of the blower  31  by control such as feedback control or feed-forward control, thereby controlling an amount of air feeding and the like. For example, the first control unit  37  determines an exhalation state of a user based on values detected by the pressure sensor  34  and the flow rate sensor  35 , and controls a pressure value of air to be fed to the user so as to be synchronized with the exhalation state. Further, the first control unit  37  controls power supply from the battery  38  to the first connector  27 . 
     Next, structure of the base unit  40  will be described. 
     As illustrated in  FIG. 1 , the base unit  40  is provided with a second housing  41  in an L-shape in side view. The second housing  41  is roughly divided into a base housing  42  in a flat rectangular parallelepiped shape, and a protruding housing  43  in a flat rectangular parallelepiped shape positioned on an upper side of the base housing  42 . 
     A dimension in a longitudinal direction of the base housing  42  is larger than a dimension in the length direction Ld of the first housing  21 . A dimension in a short direction of the base housing  42  is the same as a dimension in the width direction Wd of the first housing  21 . Note that, in the following description, the longitudinal direction of the base housing  42  of the second housing  41  is along the length direction Ld of the first housing  21 , and the short direction of the base housing  42  is along the width direction Wd of the first housing  21 . 
     The protruding housing  43  protrudes from an upper surface on a first end side in the length direction Ld of the base housing  42 . An end on a first end side in the length direction Ld of the protruding housing  43  coincides with the end on the first end side in the length direction Ld of the base housing  42 . A dimension in the height direction Td of the protruding housing  43  is substantially the same as a dimension in the height direction Td of the first housing  21 . A dimension in the width direction Wd of the protruding housing  43  is substantially the same as a dimension in the width direction Wd of the first housing  21 . A dimension in the length direction Ld of the protruding housing  43  is a value obtained by subtracting the dimension in the length direction Ld of the first housing  21  from the dimension in the longitudinal direction of the base housing  42 . 
     The base housing  42  and the protruding housing  43  both have a box shape having a cavity therein. Further, an internal space of the base housing  42  and an internal space of the protruding housing  43  are continuous with each other. A wall portion of the protruding housing  43  on a side opposite to the base housing  42 , that is, an upper wall portion is configured as a lid  44  that can be opened and closed. The lid  44  is removable, and with the lid  44  of the protruding housing  43  removed, the internal space of the protruding housing  43  and a part of the internal space of the base housing  42  are exposed. Note that, in  FIG. 5 , the base unit  40  is illustrated with the lid  44  removed. 
     As illustrated in  FIG. 5 , an upper side surface  42 U of the base housing  42  is provided with a protrusion  45  protruding toward an upper side in the height direction Td of the base housing  42 . In this embodiment, two protrusions  45  are provided for each row along the length direction Ld of the base housing  42 . Then, two rows of the protrusions  45  are provided in the width direction Wd of the base housing  42 . That is, in total, four protrusions  45  are provided. 
     In the upper side surface  42 U of the base housing  42 , a second introduction port  46  for introducing air from the outside to the inside of the base housing  42  opens. In the present embodiment, the second introduction ports  46  is plurally provided. The second introduction ports  46  are arranged so as to be aligned over substantially an entire region in the width direction Wd of the base housing  42 . Further, each of the second introduction ports  46  is arranged in a vicinity of an edge on a second end side in the length direction Ld of the upper side surface  42 U of the base housing  42 . Note that, the upper side surface  42 U of the base housing  42  functions as a surface for placing the main body unit  20 . 
     As illustrated in  FIG. 3 , an upstream side flow path  53  through which air pulled into the blower  31  of the main body unit  20  flows is defined inside the second housing  41  of the base unit  40 . In the base unit  40 , an upstream end of the upstream side flow path  53  is connected to the second introduction port  46 . 
     The second silencer  51  is mounted in midstream of the upstream side flow path  53 . The second silencer  51  attenuates a flow sound of air flowing through the upstream side flow path  53 . Note that, a size of volume of the second silencer  51  is larger than volume of the first silencer  33  of the main body unit  20 , and a sound attenuation effect is higher than that of the first silencer  33  of the main body unit  20 . 
     A downstream end of the upstream side flow path  53  is connected to a second lead-out port  47  for leading out air from the inside to the outside of the second housing  41 . As illustrated in  FIG. 5 , the second lead-out port  47  opens in a surface connected to the upper side surface  42 U of the base housing  42  of respective end surfaces on both sides in the length direction Ld of the protruding housing  43 , that is, in a second end surface  43 B which is a side surface on a second end side in the length direction Ld in the protruding housing  43 . An opening shape of the second lead-out port  47  is the same as an opening shape of the first introduction port  23  of the main body unit  20 . 
     Additionally, as illustrated in  FIG. 3 , a downstream side flow path  54  through which air fed from the blower  31  of the main body unit  20  flows is defined inside the second housing  41  of the base unit  40 . The downstream side flow path  54  is provided with a first downstream side flow path  54 A and a second downstream side flow path  54 B downstream of the first downstream flow path  54 A. A tank  72  of the humidifier  70  is mounted between the first downstream side flow path  54 A and the second downstream side flow path  54 B. In the present embodiment, the first downstream side flow path  54 A functions as a first gas flow path, and the second downstream side flow path  54 B functions as a second gas flow path. The humidifier  70  is provided with the tank  72  described above, a heater  71 , and a heater temperature sensor  80 . The tank  72  is configured to be capable of being attached to and detached from the second housing  41 , and is capable of storing water therein. Air introduced inside the humidifier  70  is led out from the humidifier  70  through the tank  72 , thereby humidifying the air. The heater  71  heats water in the tank  72 . The heater temperature sensor  80  detects a temperature of the heater  71 . 
     As illustrated in  FIG. 5 , a third introduction hole  48  for introducing air from the outside to the inside of the protruding housing  43  opens in the second end surface  43 B of the protruding housing  43  in the base unit  40 . The third introduction hole  48  is arranged so as to be aligned with the second lead-out port  47  in the width direction Wd in the protruding housing  43 . The third introduction hole  48  has a circular shape in plan view, and an outer diameter of the third introduction hole  48  is larger than an outer diameter of the first lead-out portion  25  in the first housing  21 . 
     In the second end surface  43 B, a second connector  49  for electrically connecting the main body unit  20  to the base unit  40  protrudes. The second connector  49  is a so-called male connector corresponding to a shape of the first connector  27  described above, and is provided with a plurality of terminals therein. The second connector  49  is arranged on a lower side of the third introduction hole  48 . 
     As illustrated in  FIG. 1 , a cylindrical third lead-out portion  50  for leading out air from the inside to the outside of the second housing  41  protrudes from the lid  44  of the second housing  41 . A central axis line of the third lead-out portion  50  is inclined with respect to the height direction Td in the protruding housing  43 . An internal space of the third lead-out portion  50  communicates with the downstream side flow path  54 . 
     Next, an electrical configuration of the CPAP device  10  in the base unit  40  will be described. 
     As illustrated in  FIG. 3 , the base unit  40  is provided with a second control unit  56  that controls operation of the heater  71 . The second control unit  56  may be configured as circuitry including 1) one or more processors that execute various processes in accordance with a computer program (software), 2) one or more dedicated hardware circuits, such as an application-specific integrated circuit (ASIC), that execute at least some processes of the various processes, or 3) a combination thereof. The processor includes a CPU and memories, such as a RAM and a ROM, and the memory stores program codes or directives configured to cause the CPU to execute the processes. The memory or a computer-readable medium includes any available medium that can be accessed from a general purpose or dedicated computer. 
     Electric power is supplied to the second control unit  56  from the battery  38  of the main body unit  20  with the first connector  27  of the main body unit  20 , and the second connector  49  interposed therebetween. Additionally, a signal indicating a temperature value of air detected by the temperature sensor  36  is inputted from the first control unit  37  to the second control unit  56  with the first connector  27  of the main body unit  20 , and the second connector  49  interposed therebetween. 
     The second control unit  56  sets a target heater temperature for heating water in the tank  72 , based on the inputted air temperature value. For example, the second control unit  56  sets the target heater temperature with a predetermined calculation formula. Then, the second control unit  56  is configured to drive the heater  71 , based on a heater temperature detected by the heater temperature sensor  80  so as to set the heater temperature to the target heater temperature by control such as feedback control or feed-forward control. The second control unit  56  adjusts a water temperature in the tank  72  by the heater  71 . Then, when the heater temperature reaches the target heater temperature, the second control unit  56  controls the heater  71  so as to maintain the heater temperature at the target heater temperature. 
     Next, internal structure of the base unit  40 , particularly the humidifier  70 , will be described in detail. 
     As illustrated in  FIG. 6 , a housing space S in a rectangular parallelepiped shape is defined by the internal space of the base housing  42  and the internal space of the protruding housing  43 . With the lid  44  of the base unit  40  removed, an upper side of the protruding housing  43  opens as an attachment/detachment port  43 K. The heater  71  in a plate shape is arranged on a part of the base unit  40  on a side opposite to the attachment/detachment port  43 K, that is, on a bottom of the base housing  42 . In the housing space S, the water storage tank  72  is housed on an upper side in the height direction Td of the heater  71 . The tank  72  has a substantially rectangular parallelepiped shape. Water stored in the tank  72  is heated by the heater  71 , and vaporization is promoted. In the present embodiment, the second housing  41  functions as a housing case, and the heater  71  functions as a humidification promoting mechanism. 
     With the lid  44  open, the tank  72  is taken in to the housing space S, which is an internal space of the second housing  41 , from the attachment/detachment port  43 K that opens upward in the height direction Td of the protruding housing  43 , and is taken out from the housing space S of the second housing  41 . Here, a direction in which the tank  72  is taken in to and out from the attachment/detachment port  43 K is defined as a taking in/out direction. In the present embodiment, the taking in/out direction coincides with a vertical direction, and also coincides with the height direction Td in the second use state. 
     As illustrated in  FIG. 6 , a first tank hole  73  in a circular shape in plan view for supplying air to the tank  72  opens in a wall portion on a second end side in the length direction Ld of the tank  72 . The first tank hole  73  causes the inside and the outside of the tank  72  to communicate with each other. A position of the first tank hole  73  coincides with a position of the third introduction hole  48 , when viewed from the length direction Ld. The third introduction hole  48  causes the inside and the outside of the base housing  42  to communicate with each other. That is, in the present embodiment, the third introduction hole  48  functions as a first case hole. 
     A first seal member  75  made of synthetic rubber is arranged between the tank  72  and the protruding housing  43 . The first seal member  75  is arranged in an annular shape so as to entirely surround the tank  72 , when viewed from the height direction Td. That is, the first seal member  75  extends along an inner surface of the protruding housing  43 , and is arranged so as to sandwich the tank  72  from both sides in any direction orthogonal to the taking in/out direction. 
     A dimension in the height direction Td of the first seal member  75  is larger than respective dimensions in the height direction Td of the first tank hole  73  and the third introduction hole  48 . Further, a position in the height direction Td of the first seal member  75  is set such that a center in the height direction Td of the first seal member  75  coincides with a center in the height direction Td of the first tank hole  73  and a center in the height direction Td of the third introduction hole  48 . 
     Further, the first seal member  75  has a hollow shape. A first through-hole  76  in a circular shape in plan view and serving as a communication hole penetrates a part of the first seal member  75  that faces the third introduction hole  48 . The first through-hole  76  causes an internal space of the first seal member  75  and an external space on a side of the third introduction hole  48  to communicate with each other. Similarly, a second through-hole  77  in a circular shape in plan view penetrates a part of the first seal member  75  that faces the first tank hole  73 . The second through-hole  77  causes the internal space of the first seal member  75  and an internal space in the tank  72  to communicate with each other. 
     The first seal member  75  is provided with a second fitting portion  78  protruding outward in a convex shape from an outer peripheral surface of an annular portion of the first seal member  75 , when viewed from the height direction Td. The second fitting portion  78  is in a substantially quadrangular shape in a sectional view. 
     A first fitting portion  43 H for fixing a position of the first seal member  75  is recessed in an inner surface of the protruding housing  43 . When viewed from the height direction Td, the first fitting portion  43 H extends along substantially an entirety of the inner surface of the protruding housing  43  except for a position of the third introduction hole  48 . A position in the height direction Td of the first fitting portion  43 H is the same position as a position in the height direction Td of the third introduction hole  48 . The first fitting portion  43 H is in a substantially quadrangular shape corresponding to the second fitting portion  78  in a sectional view. The second fitting portion  78  of the first seal member  75  is fitted into this first fitting portion  43 H. 
     As illustrated in  FIG. 5 , a second tank hole  74  penetrates a wall portion on an upper side in the height direction Td of the tank  72 . The second tank hole  74  causes the inside and the outside of the tank  72  to communicate with each other. The second tank hole  74  is, with the lid  44  closed, arranged at a position facing a lid hole  50 A which is an opening on a lid side of the third lead-out portion  50  of the lid  44  illustrated in  FIG. 1 . 
     As illustrated in  FIG. 5 , a second seal member  79  in an annular shape is arranged on an upper side in the height direction Td of the tank  72  so as to surround an opening edge of the second tank hole  74 . With the lid  44  mounted, the second seal member  79  is sandwiched between the wall portion on the upper side of the tank  72  and the lid  44 . Thus, the second seal member  79  that separates the second downstream side flow path  54 B leading to the inside of the tank  72  through the lid hole  50 A and the second tank hole  74 , from the housing space S, is arranged between the tank  72  and the lid  44 . 
     Next, an action of the CPAP device  10  in the first use state will be described. 
     As illustrated in  FIG. 7 , in the first use state, the main body unit  20  is in a state of being loaded into the base unit  40 . To be specific, as illustrated in  FIG. 2 , the main body unit  20  is placed on the base unit  40  such that a lower side surface  21 D in the first housing  21  faces the upper side surface  42 U of the base housing  42  in the second housing  41 . Further, the first end surface  21 A in the first housing  21  and the second end surface  43 B of the protruding housing  43  in the second housing  41  face and are in contact with each other. Thus, in the first use state, the CPAP device  10  has an elongated thin rectangular parallelepiped shape as a whole. Note that, in the present embodiment, in the first use state in which the base unit  40  is used to use the CPAP device  10 , the protruding housing  43  is used in a direction in which the protruding housing  43  is positioned on an upper side in the vertical direction of the base housing  42 . 
     As illustrated in  FIG. 3 , in the first use state, the first introduction port  23  of the first housing  21  is connected to the second lead-out port  47  of the second housing  41 , and the upstream end of the main flow path  32  of the main body unit  20  is connected to the downstream end of the upstream side flow path  53  of the base unit  40  with these first introduction port  23  and second lead-out port  47  interposed therebetween. In addition, the first lead-out portion  25  of the first housing  21  is inserted into the third introduction hole  48  of the second housing  41 , and the downstream end of the main flow path  32  of the main body unit  20  is connected to an upstream end of the downstream side flow path  54  of the base unit  40  with these first lead-out portion  25  and third introduction hole  48  interposed therebetween. 
     As illustrated in  FIG. 7 , in the first use state, a first end portion of an air tube  91  is connected to the third lead-out portion  50  of the base unit  40 , and a second end portion of the air tube  91  is connected to a mask  92 . The mask  92  is worn, for example, so as to cover a nose or mouth of a user  93 . 
     In the first use state of the CPAP device  10 , when the operation unit  22  of the main body unit  20  is operated and the power supply of the main body unit  20  is turned on, the blower  31  is driven. Here, due to the protrusion  45  provided on the upper side surface  42 U of the base housing  42  of the base unit  40 , a gap is generated between the lower side surface  21 D of the first housing  21  and the second introduction port  46 . Thus, air is pulled inside the CPAP device  10  from this gap through the second introduction port  46 . The air pulled inside the CPAP device  10  is discharged outside from the third lead-out portion  50  of the second housing  41 , through the upstream side flow path  53  of the second housing  41 , the main flow path  32  of the first housing  21 , and the downstream side flow path  54  of the second housing  41 . Thereby, the air is fed through the air tube  91  and the mask  92  into a respiratory tract of the user  93 . 
     Here, particularly in the downstream side flow path  54 , as illustrated in  FIG. 6 , first, air pressurized by the blower  31  is introduced from the third introduction hole  48 . The air flowing through the third introduction hole  48 , which is an opening on a tank side of the third introduction hole  48 , flows from the first through-hole  76  of the first seal member  75  into the internal space of the first seal member  75 , passes through the second through-hole  77 , and flows inside the tank  72  from the first tank hole  73 . The air flowing inside the tank  72  is humidified, and discharged from the third lead-out portion  50 , via the second tank hole  74  and the lid hole  50 A from the inside of the tank  72  which is the second downstream side flow path  54 B. At this time, a part of the air flowing through the first downstream side flow path  54 A also flows into the internal space of the first seal member  75 , and the first seal member  75  tries to expand. 
     Next, the CPAP device in the second use state will be described. 
     As illustrated in  FIG. 8 , in the second use state, the main body unit  20  is not loaded into the base unit  40 , that is, the CPAP device  10  is used only with the main unit  20 . In this case, the first end portion of the air tube  91  is connected to the first lead-out portion  25  of the main body unit  20 , and the second end portion of the air tube  91  is connected to the mask  92 . The mask  92  is worn, for example, so as to cover the nose or mouth of the user  93 . In the present embodiment, the humidifier  70  does not function in the second use state. 
     Next, effects of the humidifier  70  in the above first embodiment will be described. 
     (1) In the above first embodiment, in the CPAP device  10 , when the blower  31  of the main body unit  20  is driven in the first use state, air flows from the main flow path  32  of the main body unit  20  to the downstream side flow path  54  of the base unit  40 . According to the above first embodiment, first, the first seal member  75  prevents the air flowing from the main flow path  32  to the downstream side flow path  54  from leaking outside the main body unit  20  and the base unit  40 . That is, the first seal member  75  exhibits a sealing function. 
     Incidentally, as illustrated in  FIG. 9 , it is assumed that an O-ring  901  in an annular shape surrounding the first tank hole  73  when viewed from the length direction Ld is employed, as a configuration for preventing the air flowing from the main flow path  32  to the downstream side flow path  54  from leaking outside the main body unit  20  and the base unit  40 . In this case, the O-ring  901  presses the tank  72  from a second end side toward a first end side in the length direction Ld when viewed from a direction in which the tank  72  is taken in and out. Thus, as indicated by a two-dot chain line in  FIG. 9 , there is a possibility that the tank  72  is inclined due to pressing force of the O-ring  901 . As a result, a bottom surface of the tank  72  is partially separated from the heater  71 , and it becomes difficult for water in the tank  72  to be heated by the heater  71 . 
     In this regard, in the above first embodiment, the first seal member  75  has an annular shape when viewed from a direction in which the tank  72  is taking in/out, and surrounds an entire circumference of the tank  72 . Thus, as illustrated in  FIG. 6 , the first seal member  75  sandwiches the tank  72  from both sides not only in one direction orthogonal to the vertical direction, but also in any direction orthogonal to the vertical direction, when viewed from the direction in which the tank  72  is taken in and out. Thus, when the tank  72  is housed in the housing space S of the base housing  42 , the tank  72  is positioned in any direction orthogonal to the vertical direction by the first seal member  75 . Thus, it is possible to suppress displacement of the tank  72  in the housing space S of the base housing  42 . Moreover, the configuration for this positioning is realized by the first seal member  75  for preventing air from leaking outside. Thus, an increase in the number of components for positioning the tank  72  can also be prevented. 
     (2) According to the above first embodiment, the first seal member  75  has a hollow shape. Thus, air flowing from the main flow path  32  to the downstream side flow path  54  also flows into the internal space of the first seal member  75 . When pressurized air is fed into the internal space of the first seal member  75 , the first seal member  75  tries to expand. Then, the first seal member  75  trying to expand presses the tank  72 , thus positioning of the tank  72  can be made more reliable. 
     Note that, when the tank  72  is housed in the housing space S of the base housing  42 , pressurized air does not flow into the internal space of the first seal member  75 , and thus the first seal member  75  does not try to expand. Thus, when the removed tank  72  is housed in the housing space S from the attachment/detachment port  43 K, the first seal member  75  does not excessively press the tank  72 , and the tank  72  is easily inserted. 
     (3) According to the above first embodiment, the material for the first seal member  75  is synthetic rubber. Thus, first, force for pressing the tank  72  when the first seal member  75  tries to expand is relatively large, and thus reliable positioning of the tank  72  is further easily realized. On the other hand, when rigidity of the first seal member  75  is excessively high, and the tank  72  is housed in the housing space S of the base housing  42 , it is difficult to take in the tank  72  due to high resistance. In this regard, since the material for the first seal member  75  is synthetic rubber, it is easy to prevent the resistance when the tank  72  is housed in the housing space S of the base housing  42  from increasing excessively. As a result, it is possible to achieve ease of insertion when the tank  72  is housed, and reliable positioning of the tank  72 , in a compatible manner. 
     (4) According to the above first embodiment, when the second fitting portion  78  is fitted into the first fitting portion  43 H, the first seal member  75  is positioned with respect to the base housing  42 . Here, the first seal member  75  positions the tank  72  by pressing the tank  72 . Thus, there is a possibility that, when a position of the first seal member  75  with respect to the base housing  42  is displaced from a designed position, a position of the tank  72  with respect to the base housing  42  is also displaced. In this regard, according to the above first embodiment, since the first seal member  75  is positioned with respect to the base housing  42 , the position of the tank  72  positioned by the first seal member  75  is also less likely to be displaced from the designed position. 
     (5) According to the above first embodiment, in the first use state, the air tube  91  is mounted to the third lead-out portion  50  of the lid  44 . By opening and closing the lid  44 , the tank  72  can be taken out from the attachment/detachment port  43 K. At this time, the air tube  91  can be kept mounted to the lid  44 . Accordingly, in a case of being used continuously in the first use state, even when the tank  72  is repeatedly attached and detached, the air tube  91  need not be detached. 
     Second Embodiment 
     Next, a second embodiment in which a humidifier is applied to a CPAP device will be described. Note that, in the following description of the second embodiment, a configuration similar to that of the first embodiment is assigned the same reference numeral, and a specific description thereof will be omitted or simplified. 
     As illustrated in  FIG. 10 , in a humidifier  170 , an upper side of the protruding housing  43  opens as the attachment/detachment port  43 K. Note that, in this second embodiment, the lid  44  in the first embodiment is not provided, and the attachment/detachment port  43 K is always in a state of being open. A third lead-out portion  150  is mounted to an upper wall portion of a tank  172 . The third lead-out portion  150  has a cylindrical shape, and causes the inside and the outside of the tank  172  to communicate with each other. 
     A contact surface  172 S of an outer surface of the tank  172  that is in contact with a first seal member  175  is inclined so as to approach an inner wall of the second housing  41  as a distance to a lower side in the height direction Td decreases. In addition, the contact surface  172 S faces a side of the attachment/detachment port  43 K in a taking in/out direction of the tank  172 . Then, the first seal member  175  is in contact with the contact surface  172 S on an upper side in the height direction Td, which is the taking in/out direction of the tank  172 . Further, a surface of the first seal member  175  that is in contact with the contact surface  172 S is inclined so as to approach the tank  172  as a distance to an upper side in the height direction Td decreases. Then, the first seal member  175  fills a space between the tank  172  and the inner wall of the second housing  41 . 
     Next, an action of the humidifier  170  in the second embodiment will be described. 
     In a first use state of the CPAP device  10 , the tank  172  is housed in the second housing  41 , and the air tube  91  is mounted to the third lead-out portion  150  of the tank  172 . Then, air humidified in the humidifier  170  is fed from the third lead-out portion  150  to a respiratory tract of the user  93  through the air tube  91 . 
     Here, when a part of the air flowing through the first downstream side flow path  54 A flows into an internal space of the first seal member  175 , and the first seal member  175  tries to expand, the contact surface  172 S of the tank  172  is pressed by the first seal member  175 . As a result, the tank  172  is pressed toward a lower side in the height direction Td, which is the taking in/out direction of the tank  172 . 
     Next, effects of the humidifier  170  in the second embodiment will be described. In the second embodiment, in addition to the effects (1) to (4) of the above first embodiment, the following effects are exhibited. 
     (6) According to the second embodiment, when the first seal member  175  tries to expand, the contact surface  172 S of the tank  172  is pressed, and thus the tank  172  as a whole is pressed toward the lower side in the height direction Td, which is the taking in/out direction of the tank  172 . Here, in the present embodiment, the heater  71  for heating water in the tank  172  is arranged at a bottom of the tank  172 . Thus, the first seal member  175  performs positioning also in the height direction Td such that the tank  172  is in contact with the heater  71 . As a result, since the tank  172  and the heater  71  are in contact with each other, it is possible to prevent insufficient heating of water stored in the tank  172  by the heater  71 , and insufficient humidification of air supplied to the user  93 . 
     (7) According to the second embodiment, the third lead-out portion  150  is directly mounted to the tank  172 , thus, by replacing the tank  172 , the third lead-out portion  150  is also replaced together. Thus, for example, when used by a new user  93 , by replacing the tank  172 , the third lead-out portion  150  can also be replaced at the same time, thus, the new user  93  can use the CPAP device  10  as a clean CPAP device  10 . 
     Third Embodiment 
     Next, a third embodiment in which a humidifier is applied to a CPAP device will be described. In this third embodiment, the configuration of the humidifier  70  in the first embodiment is partially changed. Note that, in the following description of the third embodiment, a configuration similar to that of the first embodiment is assigned the same reference numeral, and a specific description thereof will be omitted or simplified. 
     As illustrated in  FIG. 11 , in the tank  72  of a humidifier  270 , an in-tank flow path portion  281  in a cylindrical shape extends from an opening edge of the first tank hole  73  of the tank  72  toward the inside of the tank  72 . An opening of the in-tank flow path portion  281  on a side opposite to the first tank hole  73  extends closer to a first end side than a center of the tank  72  in the length direction Ld. On the other hand, a tip end of the in-tank flow path portion  281  does not reach an inner wall of the tank  72 . That is, the in-tank flow path portion  281  opens inside the tank  72 . 
     In this third embodiment, a dimension in the height direction Td of the first seal member  275  is close to a dimension in a vertical direction of the tank  72 . Here, in an internal space of the first seal member  275 , a space closer to a side of the attachment/detachment port  43 K than the first tank hole  73  is defined as an upper side space US, and a space closer to a bottom side of the tank  72  than the first tank hole  73  is defined as a lower side space LS. In this case, a distance from the first tank hole  73  to a lower end of the lower side space LS is larger than a distance from the first tank hole  73  to an upper end of the upper side space US. In the present embodiment, the upper side space US and the lower side space LS have the same dimension in a direction perpendicular to the height direction Td. As a result, volume of the lower side space LS is larger than volume of the upper side space US. 
     Next, an action and effects of the humidifier  270  in the third embodiment will be described. In the third embodiment, in addition to the effects (1) to (5) of the above first embodiment, the following effects are exhibited. 
     (8) In the above third embodiment, the humidifier  270  is applied to the CPAP device  10 . As illustrated in  FIG. 7 , the CPAP device  10  is connected to the user  93  with the air tube  91  and the mask  92  interposed therebetween. Then, the CPAP device  10  is used to supply fluid to the user  93  for a sleep-related therapy such as obstructive sleep apnea (OSA) syndrome. The CPAP device  10  supplies air at a pressure higher than atmospheric pressure from the blower  31  to the mask  92  worn on a mouth or nose of the user  93  to open a respiratory tract. Thus, when the user  93  turns over during sleep, or the like, an entirety of the CPAP device  10  is inclined in some cases. Thus, the second housing  41  functioning as a housing case is also inclined in some cases. 
     In the above third embodiment, in the tank  72 , the in-tank flow path portion  281  extends inward the tank  72  from the first tank hole  73 . Thus, even when the second housing  41  is inclined such that a second end side in the length direction Ld goes to a lower side, an opening of the in-tank flow path portion  281  on a side of the tank  72  is positioned on an upper side than a water level in the tank  72 . Thus, water in the tank  72  is less likely to flow into the in-tank flow path portion  281 , thus flowing of the water in the tank  72  into the main body unit  20  is suppressed. 
     (9) In the above third embodiment, in the internal space of the first seal member  275 , the volume of the lower side space LS is larger than the volume of the upper side space US. Thus, even when water in the tank  72  flows into the first seal member  275  from the first tank hole  73 , the water is likely to pool in the lower side space LS of the first seal member  275 . Thus, flowing of water from the first through-hole  76  of the first seal member  275  into the main body unit  20  is suppressed. 
     Fourth Embodiment 
     Next, a fourth embodiment in which a humidifier is applied to a CPAP device will be described. In this fourth embodiment, the configuration of the humidifier  70  in the first embodiment is partially changed. Note that, in the following description of the fourth embodiment, a configuration similar to that of the first embodiment is assigned the same reference numeral, and a specific description thereof will be omitted or simplified. 
     As illustrated in  FIG. 12 , in a humidifier  370 , an upper side of the protruding housing  43  opens as the attachment/detachment port  43 K. Note that, in this fourth embodiment, the lid  44  in the first embodiment is not provided, and the attachment/detachment port  43 K is always in a state of being open. 
     A second tank hole  374  in a circular shape in plan view for discharging humidified air from the tank  72  penetrates a wall portion on a first end side in the length direction Ld of the tank  72  of the humidifier  370 . The second tank hole  374  causes the inside and the outside of the tank  72  to communicate with each other. The second tank hole  374  is arranged at the same position as that of a first seal member  375  in the height direction Td. 
     Additionally, an exhaust side case hole  382  in a circular shape in plan view that functions as a second case hole opens in a wall portion on the first end side in the length direction Ld of the second housing  41 . The exhaust side case hole  382  causes the inside and the outside of the second housing  41  to communicate with each other. In addition, a position of the exhaust side case hole  382  coincides with that of the second tank hole  374  in the height direction Td and the width direction Wd. Then, a third lead-out portion  350  in a cylindrical shape is mounted to an outer side portion of the second housing  41  of the exhaust side case hole  382 . The third lead-out portion  350  extends toward the first end side in the length direction Ld. 
     The first seal member  375  is arranged between the second tank hole  374  and the exhaust side case hole  382 . In addition, of the first seal member  375 , a third through-hole  383  penetrates at a position facing the second tank hole  374 , and a fourth through-hole  384  penetrates at a position facing the exhaust side case hole  382 . Then, the first seal member  375  separates the second downstream side flow path  54 B leading to the inside of the tank  72  through the exhaust side case hole  382  and the second tank hole  374 , from an external space of the second housing  41 . That is, the first seal member  375  separates not only the first downstream side flow path  54 A from the external space of the second housing  41 , but also the second downstream side flow path  54 B from the external space of the second housing  41 . 
     Next, an action and effects of the humidifier  370  in the fourth embodiment will be described. In the fourth embodiment, in addition to the effects (1) to (4) of the above first embodiment, the following effects are exhibited. 
     (10) According to the fourth embodiment, the third lead-out portion  350  is arranged without necessarily protruding to an upper side of the second housing  41 . Thus, the CPAP device  10  can be reduced in height. 
     (11) According to the above fourth embodiment, the first seal member  375  has, in addition to the function of separating the first downstream side flow path  54 A from the external space of the second housing  41 , the function of separating the second downstream side flow path  54 B from the external space of the second housing  41 . Thus, a function of sealing an upstream side and a downstream side of the tank  72  can be achieved by a single member. Thus, the number of components of the humidifier  370  can be reduced. 
     Each of the above embodiments can be modified and implemented as follows. Each embodiment, and modifications described below can be combined and implemented within a range where technical inconsistency does not occur. 
     In each of the embodiments, the configuration of the second housing  41  functioning as the housing case is not limited to the example of each embodiment described above. It is sufficient that the housing space S for housing the tank  72  is defined in the second housing  41 , and for example, only the protruding housing  43  may be configured as a housing case. 
     In each of the above embodiments, the shape of the tank  72  is not limited to the example of each of the above embodiments. For example, the shape may be a cylindrical shape or a polygonal shape. 
     In each of the above embodiments, the heater  71  functions as the humidification promoting mechanism, however, an ultrasonic generator may be provided as a humidification promoting mechanism instead of the heater  71 . In this case, the ultrasonic generator does not necessarily have to be in contact with the tank  72 , and when the ultrasonic generator is installed such that a distance from the ultrasonic generator to water in the tank  72  is a desired value, the water in the tank  72  can be efficiently atomized by ultrasonic waves, and vaporization can be promoted. 
     In each of the above embodiments, the position of the attachment/detachment port  43 K need not be on the upper side in the height direction Td of the second housing  41 . For example, the attachment/detachment port  43 K may open in the wall portion on the first end side in the length direction Ld of the second housing  41 . In this case, a taking in/out direction of the tank  72  is the length direction Ld, and a bottom of the tank  72  is, of a wall portion of the tank  72 , the wall portion on the second end side in the length direction Ld, which is on a side opposite to the attachment/detachment port  43 K in the taking in/out direction of the tank  72 . 
     In each of the above embodiments, the configuration is adopted in which air is supplied from the third introduction hole  48 , and the air is discharged from the lid hole  50 A of the tank  72 , however, the direction in which the air flows is not limited to the example of each of the above embodiments. That is, air may be supplied from the third lead-out portion  50  to the tank  72 , and pass through inside the tank  72 , and the air may be discharged to the third introduction hole  48 , via the first seal member  75 . In this case, for example, it is sufficient that a unit that is not provided with the blower  31 , but is provided with another blower is mounted to the third lead-out portion  50 , and the blower is driven. 
     In each of the above embodiments, the first seal member need not extend in an annular shape so as to surround an entire periphery of the tank  72 , when viewed from the taking in/out direction of the tank  72 . It is sufficient that the first seal member  75  at least sandwiches the tank  72  from both sides in the length direction Ld, which is one direction orthogonal to the taking in/out direction. For example, in the first embodiment, the first seal member  75  may extend so as to surround, of side surfaces of the tank  72 , the side surface on the second end side in the length direction Ld and the side surfaces on both the sides in the width direction Wd, and so as not to surround the side surface on the first end side in the length direction Ld. In this case, with the width direction Wd as the one direction, the tank  72  is sandwiched from both sides in the one direction. 
     In each of the above embodiments, the shape of the first seal member need not be a hollow member. In this case, for example, in the first embodiment, only a part that causes the first through-hole  76  and the second through-hole  77  to communicate with each other may be a space configuring the first downstream side flow path  54 A, and the other parts may be solid members. 
     In each of the above embodiments, the first seal member is configured as a single member, but the first seal member may be configured with a plurality of members. In this case, for example, as illustrated in  FIG. 13 , in a humidifier  470 , it is sufficient that a first seal member  475  is configured with an attachment/detachment port side seal member  475 A, and a bottom surface side seal member  475 B. The attachment/detachment port side seal member  475 A is a solid member in an annular shape, and extends so as to surround an entire periphery of the tank  72 , when viewed from a taking in/out direction of the tank  72 . Then, the attachment/detachment port side seal member  475 A is arranged closer to a side of the attachment/detachment port  43 K than the first tank hole  73  and the third introduction hole  48  in the taking in/out direction of the tank  72 . Further, the bottom surface side seal member  475 B is a solid member in an annular shape, and extends so as to surround an entire periphery of the tank  72 , when viewed from the taking in/out direction of the tank  72 . Then, the bottom surface side seal member  475 B is arranged closer to a bottom surface side of the tank  72  than the first tank hole  73  and the third introduction hole  48  in the taking in/out direction of the tank  72 . According to such a configuration, the first seal member can be configured with two annular rings each having a relatively simple shape. Thus, advantage in terms of cost may be obtained. 
     In each of the above embodiments, the material for the first seal member is not limited to the example of each of the above embodiments. For example, the material for the first seal member may be resin or elastomer. When the material for the first seal member is elastomer, similarly to rubber, the first seal member has both ease of deformation and appropriate rigidity, thus, it is possible to achieve ease of insertion into the housing space S when the tank  72  is housed, and reliable positioning of the tank  72  in the second housing  41  in a compatible manner. 
     In each of the above embodiments, the configuration of the first fitting portion  43 H and the second fitting portion  78  is not limited to the example of each of the above embodiments. For example, the convex shape of the first fitting portion  43 H and the concave shape of the second fitting portion  78  may be configured to be reversed, or the first fitting portion  43 H may be provided on the outer surface of the tank  72 . Further, the first fitting portion  43 H and the second fitting portion  78  need not be provided. 
     In the third embodiment, the shape of the in-tank flow path portion  281  is not limited to the example of the above third embodiment. For example, the opening of the in-tank flow path portion  281  on the inner side of the tank  72  may open to the second end side in the length direction Ld of the tank  72 , or may be curved. The shape may be appropriately changed in accordance with the shape of the tank  72 . 
     In the above first and third embodiments, the configuration of the lid  44  is not limited to the example of each of the above embodiments. For example, the lid  44  may be configured to rotate, with a side on the first end side in the length direction Ld as a rotation center. 
     In each of the above embodiments, the tank  72  is sandwiched from both sides in one direction by the first seal member configured with a single member, however, the tank  72  may be sandwiched from both sides in one direction by the first seal member and another member. For example, as illustrated in  FIG. 14 , in a humidifier  570 , a tank  572  may be sandwiched by a first seal member  575  and an elastic member  585  from both sides in one direction. To be specific, a third introduction hole  548  opens at a center in the width direction Wd of a second end surface  543 B of a protruding housing  543  of a base unit  540 . 
     A first tank hole  573  for supplying air to the tank  572  opens in a wall portion on a second end side in the length direction Ld of the tank  572 . The first tank hole  573  causes the inside and the outside of the tank  572  to communicate with each other. A position of the first tank hole  573  coincides with a position of the third introduction hole  548 , when viewed from the length direction Ld. The third introduction hole  548  causes the inside and the outside of the second housing  541  to communicate with each other. That is, in the present modification, the third introduction hole  548  functions as a first case hole. The first seal member  575  in an annular shape made of synthetic rubber is arranged between the tank  572  and the protruding housing  543 . The first seal member  575  has a dimension that surrounds an opening edge of the third introduction hole  548  and the first tank hole  573 , when viewed from the length direction Ld. Additionally, a second tank hole  574  for discharging air from the tank  572  opens in a wall portion on an upper side of the tank  572 . 
     Here, in addition to the first seal member  575 , three of the elastic members  585  are arranged between the tank  572  and the protruding housing  543 . The elastic member  585  is a member in a hollow shape made of synthetic rubber, and the three elastic members  585  are positioned at both outer surfaces in the width direction Wd of the tank  572 , and an outer surface on a first end side in the length direction Ld of the tank  572 . In particular, the elastic member  585  positioned at the outer surface on the first end side in the length direction Ld of the tank  572  is arranged at the same position as that of the first seal member  575  in the width direction Wd. That is, the elastic member  585  positioned at the outer surface on the first end side in the length direction Ld of the tank  572  is arranged on a side opposite to the first seal member  575  with the tank  572  interposed therebetween in the length direction Ld which is one direction orthogonal to the taking in/out direction, when viewed from the taking in/out direction of the tank  572 . 
     In addition, in this modification, an internal communication path  586  that causes a space inside the third introduction hole  548  and an internal space of each of the elastic members  585  to communicate with each other is defined inside the protruding housing  543 . In a first use state, when air flows through the third introduction hole  548 , the air flows into the elastic member  585  through the internal communication path  586 . In this case, when trying to expand, the elastic member  585  can press the tank  572  to position the tank  572 . 
     In each of the above embodiments, the humidifier  70  is not limited to be applied to the CPAP device  10 . For example, the humidifier  70  may be applied to a respirator. 
     In each of the above embodiments, the configuration of the base unit  40  is not limited to the example of each of the above embodiments. For example, the second silencer  51  need not be provided. 
     In each of the above embodiments, the CPAP device  10  need not be used in the second use state. That is, the CPAP device  10  may be used only in the first use state, and used with the blower  31  constantly fixed to the base unit  40 . 
     REFERENCE SIGNS LIST 
     
         
         
           
               10  CPAP DEVICE 
               20  MAIN BODY UNIT 
               21  FIRST HOUSING 
               21 A FIRST END SURFACE 
               21 B DENT PORTION 
               21 C DENT SURFACE 
               21 D LOWER SIDE SURFACE 
               21 U UPPER SIDE SURFACE 
               22  OPERATION UNIT 
               22 A SWITCH 
               22 B SWITCH 
               23  FIRST INTRODUCTION PORT 
               24  FILTER 
               25  FIRST LEAD-OUT PORTION 
               27  FIRST CONNECTOR 
               31  BLOWER 
               32  MAIN FLOW PATH 
               33  FIRST SILENCER 
               34  PRESSURE SENSOR 
               35  FLOW RATE SENSOR 
               36  TEMPERATURE SENSOR 
               37  FIRST CONTROL UNIT 
               38  BATTERY 
               40  BASE UNIT 
               41  SECOND HOUSING 
               42  BASE HOUSING 
               42 U UPPER SIDE SURFACE 
               43  PROTRUDING HOUSING 
               43 B SECOND END SURFACE 
               43 H FIRST FITTING PORTION 
               43 K ATTACHMENT/DETACHMENT PORT 
               44  LID 
               45  PROTRUSION 
               46  SECOND INTRODUCTION PORT 
               47  SECOND LEAD-OUT PORT 
               48  THIRD INTRODUCTION HOLE 
               49  SECOND CONNECTOR 
               50  THIRD LEAD-OUT PORTION 
               50 A LID HOLE 
               51  SECOND SILENCER 
               53  UPSTREAM SIDE FLOW PATH 
               54  DOWNSTREAM SIDE FLOW PATH 
               56  SECOND CONTROL UNIT 
               60  SEALING MEMBER 
               61  FIXING PORTION 
               62  PROTRUDING PORTION 
               70  HUMIDIFIER 
               71  HEATER 
               72  TANK 
               73  FIRST TANK HOLE 
               74  SECOND TANK HOLE 
               75  FIRST SEAL MEMBER 
               76  FIRST THROUGH-HOLE 
               77  SECOND THROUGH-HOLE 
               78  SECOND FITTING PORTION 
               79  SECOND SEAL MEMBER 
               80  HEATER TEMPERATURE SENSOR 
               91  AIR TUBE 
               92  MASK 
               93  USER 
               150  THIRD LEAD-OUT PORTION 
               170  HUMIDIFIER 
               172  TANK 
               172 S CONTACT SURFACE 
               175  FIRST SEAL MEMBER 
               270  HUMIDIFIER 
               275  FIRST SEAL MEMBER 
               281  IN-TANK FLOW PATH PORTION 
               350  THIRD LEAD-OUT PORTION 
               370  HUMIDIFIER 
               374  SECOND TANK HOLE 
               375  FIRST SEAL MEMBER 
               382  EXHAUST SIDE CASE HOLE 
               383  THIRD THROUGH-HOLE 
               384  FOURTH THROUGH-HOLE 
               470  HUMIDIFIER 
               475  FIRST SEAL MEMBER 
               475 A ATTACHMENT/DETACHMENT PORT SIDE SEAL MEMBER 
               475 B BOTTOM SURFACE SIDE SEAL MEMBER 
               540  BASE UNIT 
               542  SECOND HOUSING 
               543  PROTRUDING HOUSING 
               543  SECOND END SURFACE 
               548  THIRD INTRODUCTION HOLE 
               570  HUMIDIFIER 
               572  TANK 
               573  FIRST TANK HOLE 
               574  SECOND TANK HOLE 
               575  FIRST SEAL MEMBER 
               585  ELASTIC MEMBER 
               586  INTERNAL COMMUNICATION PATH 
               901  O-RING 
             S HOUSING SPACE 
             US UPPER SIDE SPACE 
             LS LOWER SIDE SPACE