Blower for breathing apparatus
A blower configured for a breathing apparatus which can have a diffuser for increasing static pressure and/or reducing noise and/or mitigating pressure instabilities and/or managing reverse flow. The diffuser can be located within a housing, such as along with a motor, between an impeller and an outlet. The diffuser can include diffuser elements arranged in cascades, and can include one or more circumferential rings to direct air.
1. A blower for a breathing apparatus comprising:
a housing with an inlet and an outlet,
an impeller,
a motor within the housing for rotating the impeller,
a diffuser within the housing between the impeller and the outlet, the diffuser comprising a plate with a plurality of diffuser vanes, wherein the plurality of diffuser vanes are arranged in a plurality of cascades on the plate, each cascade comprising a series of the diffuser vanes configured to accommodate movement of reverse airflow, wherein each of the diffuser vanes of the plurality of cascades narrows from a radially outward end to a radially inward end, wherein the radially outward end of each of the diffuser vanes of the plurality of cascades is a furthest point from a center of the plate and the radially inward end of each of the diffuser vanes of the plurality of cascades is a closest point to the center of the plate, a
plurality of circumferential diffuser elements arranged proximate an outer perimeter of the diffuser plate and configured to direct airflow from a perimeter of the impeller to the plurality of diffuser vanes, and wherein a spacing between each pair of adjacent cascades of the plurality of cascades increases from narrow to wide as the each pair of adjacent cascades extend toward the center of the plate.
2. A blower according to claim 1 wherein each diffuser vane is offset from adjacent diffuser vanes in the cascade.
3. A blower according to claim 1 wherein the diffuser vanes in each cascade are arranged along a curved spiral line from the outer perimeter to the center of the plate.
4. A blower according to claim 1 wherein the diffuser vanes comprise a rounded leading edge and two opposed curved lateral edges.
5. A blower according to claim 4 , wherein the two lateral edges converge at and join at a curved endpoint in an elongated tail.
6. A blower according to claim 4 , wherein the diffuser vanes are aerofoils.
7. A blower according to claim 1 wherein the diffuser vanes are arranged in a cascade spiral from a corresponding circumferential diffuser element towards the center of the plate.
8. A blower according to claim 1 , wherein the blower comprises multiple diffusers and multiple impellers.
9. A blower according to claim 1 comprising an annular ramped wall around the impeller to reduce flutter.
10. A blower according to claim 9 , wherein the plate includes the annular ramped wall.
11. A blower according to claim 1 , wherein the blower includes a blower outlet, and wherein the plate includes a flow guide configured to promote a smooth redirection of flow from the diffuser towards the blower outlet.
12. A blower according to claim 11 , wherein the flow guide extends from the plate and tapers in diameter towards a point.
13. A blower according to claim 12 , wherein the taper of the flow guide increases along a length of the flow guide.
14. A blower according to claim 11 , wherein the blower outlet comprises an annular tube and a central aperture.
15. A blower according to claim 14 , wherein the blower outlet is beveled or arcuate where the blower outlet defines the central aperture.
16. A blower according to claim 1 , wherein the diffuser includes a second plate, and wherein the diffuser vanes extend between the plate and the second plate.
17. A blower according to claim 16 , wherein the diffuser vanes and the plate are integrally formed.
18. A blower according to claim 16 , wherein the plate and the second plate are integrally formed.
19. A blower for a breathing apparatus comprising:
a housing with an inlet and an outlet,
an impeller,
a motor within the housing for rotating the impeller,
a diffuser within the housing between the impeller and the outlet, the diffuser comprising a plurality of diffuser vanes on a plate, wherein the plurality of diffuser vanes are arranged in a plurality of cascades, each cascade comprising a series of the diffuser vanes configured to accommodate movement of reverse airflow, wherein each of the diffuser vanes of the plurality of cascades narrows from a radially outward end to a radially inward end, wherein the radially outward end of each of the difusser vanes of the plurality of cascades is a furthest point from a center of the plate and the radially inward end of each of the diffuser vanes of the plurality of cascades is a closest point to the center of the plate, a
plurality of circumferential diffuser elements arranged on an internal wall of the housing between the impeller and the plate, the plurality of circumferential diffuser elements proximate an outermost perimeter of the diffuser vanes and configured to direct airflow from a perimeter of the impeller to the plurality of diffuser vanes, and wherein a spacing between each pair of adjacent cascades of the plurality of cascades increases from narrow to wide as the each pair of adjacent cascades extend toward the center of the plate.