Apparatus for regulated delivery of a gas, notably respiratory assistance apparatus

1. An apparatus for regulated delivery of a gas comprising:

a fan including a motor, an impeller driven by the motor, and a fan scroll containing the impeller, the motor being contained in a motor casing having a first end connected to the fan scroll and a second end situated on a side opposite to the fan scroll; and

a fan casing for receiving the fan, the fan casing defining around the fan a space for flow of gas for cooling the fan, the space having a gas inlet situated at said second end of the motor casing;

wherein:

said motor casing comprises a peripheral wall around which flows the gas for cooling the fan;

said first end of the motor casing comprises at least one first inlet hole for admission of cooling gas into the fan casing; and

said second end of the motor casing comprises at least one second hole for evacuation of the cooling gas from the fan casing, the second hole or holes being arranged in a traverse end wall and separated from said gas inlet of said fan casing to prevent capture of hot cooling gasses leaving the motor casing by said inlet for admission of cooling gas into said space; and

wherein the cooling gas is constituted by a portion of the gas delivered by the apparatus, said first hole or holes communicating with the interior of the fan scroll so a portion of the gas under pressure delivered by the apparatus passes through the first hole or holes and then passes through the motor casing and flows to the exterior of the motor casing via said second hole or holes.

2. The apparatus according to claim 1 , wherein said first end of the motor casing fits in an opening located at the bottom of the fan scroll so that said first hole or each first hole opens directly into the fan scroll and is situated immediately below the impeller.

3. The apparatus according to claim 1 , further comprising a soundproofing casing around said fan casing and rigidly fastened thereto.

4. The apparatus according to claim 3 , wherein the soundproofing casing comprises a conduit for direct evacuation to outside of the cooling gas that has passed through the motor casing.

5. The apparatus according to claim 3 , wherein the soundproofing casing comprises an orifice or conduit for recirculation of the cooling gas that has passed through the motor casing toward the fan scroll.

6. The apparatus according to claim 1 , wherein the fan comprises a sealing part isolating said second hole or holes from said gas inlet for admission of gas into said space.

7. The apparatus according to claim 6 , wherein the sealing part takes the form of a sealing skirt a first tubular portion of which fits around the peripheral wall of the motor casing, said second hole or holes being arranged outside the area of application of the first tubular portion against the peripheral wall, in a transverse end wall of the fan casing.

8. The apparatus according to claim 7 , wherein said sealing skirt comprises a second tubular portion fixed to the soundproofing casing.

9. The apparatus according to claim 8 , wherein the sealing skirt comprises an intermediate third tubular portion between said first and second tubular portions and flexibly connecting these first and second tubular portions.

10. The apparatus according to claim 9 , wherein said third tubular portion is formed by a thin wall connected to the radially internal wall of said first tubular portion and to the radially internal wall of said second tubular portion.

11. The apparatus according to claim 1 , wherein the fan casing receiving the fan has a shape that espouses that of the motor casing and that of the fan scroll so that the wall of the fan casing is at a substantially constant distance from the wall of this motor casing and the wall of this fan scroll.

12. An apparatus for regulated delivery of a gas comprising:

a fan including a motor, an impeller driven by the motor, and a fan scroll containing the impeller, the motor being contained in a motor casing having a first end connected to the fan scroll and a second end situated on a side opposite to the fan scroll; and

a fan casing for receiving the fan, the fan casing defining around the fan a space for flow of gas for cooling the fan, the space having a gas inlet situated at said second end of the motor casing;

wherein:

said motor casing comprises a peripheral wall around which flows the gas for cooling the fan;

said first end of the motor casing comprises at least one first inlet hole for admission of cooling gas into the fan casing;

said second end of the motor casing comprises at least one second hole for evacuation of the cooling gas from the fan casing, the second hole or holes being arranged in a traverse end wall and separated from said gas inlet of said fan casing to prevent capture of hot cooling gasses leaving the motor casing by said inlet for admission of cooling gas into said space;

wherein the fan comprises at said second end of the motor casing, a bearing guiding a shaft of the motor, wherein the motor casing comprises a covering wall completely covering the bearing and thus eliminating any possibility of the cooling gas passing through this bearing.

13. The apparatus according to claim 12 , wherein the shaft of the motor whereof is extended beyond a transverse wall on said second end of the motor casing to receive a balancing weight, wherein said covering wall is formed by a cap mounted on the transverse wall, covering the whole of the portion of the shaft of the motor that is extended beyond said transverse wall and said bearing.

14. An apparatus for regulated delivery of a gas comprising:

a fan including a motor, an impeller driven by the motor, and a fan scroll containing the impeller, the motor being contained in a motor casing having a first end connected to the fan scroll and a second end situated on a side opposite to the fan scroll; and

a fan casing for receiving the fan, the fan casing defining around the fan a space for flow of gas for cooling the fan, the space having a gas inlet situated at said second end of the motor casing;

wherein:

said motor casing comprises a peripheral wall around which flows the gas for cooling the fan;

said first end of the motor casing comprises at least one first inlet hole for admission of cooling gas into the fan casing; and

said second end of the motor casing comprises at least one second hole for evacuation of the cooling gas from the fan casing, the second hole or holes being arranged in a traverse end wall and separated from said gas inlet of said fan casing to prevent capture of hot cooling gasses leaving the motor casing by said inlet for admission of cooling gas into said space;

wherein said fan scroll comprises a pressurized gas outlet tube, comprising a sealing part, a first tubular portion around said tube, a second tubular portion mounted in a soundproofing casing containing said fan casing, and an intermediate third tubular portion between said first and second tubular portions connected to the first and second tubular portions.