Continuous positive airway pressure apparatus

1. A continuous positive airway pressure (CPAP) apparatus that feeds air suctioned into the CPAP apparatus to a respiratory tract of a user, the CPAP apparatus comprising:

a first unit including an air blower and a first housing in which the air blower is housed; and

a second unit including a second housing and being attachable to and detachable from the first unit, wherein

the first housing comprises

a first inlet port through which air is introduced from outside the first housing,

a first outlet port through which air is discharged from inside the first housing, and

a first flow path in which the air blower is provided and that connects the first inlet port and the first outlet port,

the second housing comprises

a second inlet port through which air is introduced from outside the second housing,

a second outlet port through which air is discharged from inside the second housing, and

a second flow path that connects the second inlet port and the second outlet port,

the first unit further includes a first silencer provided in a portion of the first flow path that is located between the first inlet port and the air blower,

the second unit further includes a second silencer provided in the second flow path,

in a first use state of the CPAP apparatus where the second unit is attached to the first unit, the second outlet port is connected to the first inlet port, and

in a second use state of the CPAP apparatus where the second unit is not attached to the first unit, the first inlet port is opened to outside.

2. The CPAP apparatus according to claim 1 , wherein

a volume occupying a portion functioning as the second silencer is larger than a volume occupying a portion functioning as the first silencer.

3. The CPAP apparatus according to claim 1 , wherein

the first silencer includes a wider portion and a narrower portion that are disposed side by side in a direction in which the first flow path extends, and

the second silencer includes a resonant tube that is branched from the second flow path.

4. The CPAP apparatus according to claim 3 , wherein

a cross-sectional area of the narrower portion that is orthogonal to an air flowing direction is smaller than a cross-sectional area of the wider portion that is orthogonal to the air flowing direction, and

the narrow portion is disposed downstream from the wider portion in the air flowing direction.

5. The CPAP apparatus according to claim 1 , wherein

the first housing or the second housing is provided with a gasket so as to surround each of the first inlet port and the second outlet port in the first use state.

6. The CPAP apparatus according to claim 1 , wherein

the second inlet port is provided in a portion of the second housing that faces the first housing at a distance from the first housing in the first use state.

7. The CPAP apparatus according to claim 6 , wherein

the second inlet port is disposed at an outer surface of the second housing, and a concave portion is disposed at an outer surface of the first housing at a position faces the second inlet port, the concave portion being recessed from a surrounding area.

8. The CPAP apparatus according to claim 1 , wherein

the second housing further comprises

a third inlet port through which air is introduced from outside the second housing,

a third outlet port through which air is discharged from inside the second housing, and

a third flow path that connects the third inlet port and the third outlet port,

the second unit further includes a humidifying mechanism provided in the third flow path, and

the third inlet port is connected to the first outlet port in the first use state.

9. The CPAP apparatus according to claim 8 , wherein

the first housing comprises

a mounting surface located vertically on a lower side in the first use state, and

a first connection surface provided with the first inlet port and the first outlet port,

the second housing includes a bottom plate portion disposed vertically on a lower side in the first use state,

the second silencer and the humidifying mechanism are disposed side by side in a horizontal direction on the bottom plate portion in the first use state,

the second housing comprises

a stage surface located vertically above the second silencer in the first use state,

an upper surface located vertically above the humidifying mechanism and located higher than the stage surface in the first use state, and

a second connection surface connecting the stage surface and the upper surface and provided with the second outlet port and the third inlet port, and

the second unit is attached to the first unit such that the mounting surface faces the stage surface and the first connection surface faces the second connection surface, so as to connect the second outlet port to the first inlet port and to connect the third inlet port to the first outlet port.

10. The CPAP apparatus according to claim 1 , further comprising a third unit that includes a third housing and that is attachable to and detachable from the first unit, wherein

the third housing comprises

a third inlet port through which air is introduced from outside the third housing,

a third outlet port through which air is discharged from inside the third housing, and

a third flow path that connects the third inlet port and the third outlet port,

the third unit further includes a humidifying mechanism provided in the third flow path, and

the third inlet port is connected to the first outlet port in the first use state.