Compressor
A compressor has a rotor assembly having an impeller for generating an airflow through the compressor, a stator core assembly for causing rotation of the impeller, and a diffuser assembly for acting on the airflow generated by the impeller. The diffuser assembly has a first diffuser stage and a second diffuser stage. The first and second diffuser stages are separate components connected to one another by a fastener.
1. A compressor comprising a rotor assembly having an impeller for generating an airflow through the compressor, a stator core assembly for causing rotation of the impeller, and a diffuser assembly for acting on the airflow generated by the impeller, wherein the diffuser assembly comprises a first diffuser stage and a second diffuser stage, the first and second diffuser stages comprising separate components connected to one another by a fastener;
wherein the first diffuser stage comprises a first hub, a first outer wall, and a first plurality of diffuser blades extending between the first hub and the first outer wall, and the second diffuser stage comprises a second hub, a second outer wall, and a second plurality of diffuser blades extending between the second hub and the second outer wall; and
wherein the fastener extends between the first and second hubs at a location remote from an outer diameter of the first and the second hubs, such that the fastener is removed from the common flow path.
2. The compressor of claim 1 , wherein the first and second diffuser stages are formed by separate moulding processes.
3. The compressor of claim 1 , wherein the first and second hubs and the first and second outer walls comprise a cylindrical global form.
4. The compressor of claim 1 , wherein at least one of the first or second hub is hollow, and the other of the second or first hub, comprises a locating projection which extends into the hollow interior of the first or second hub.
5. The compressor of claim 1 , wherein the second diffuser stage comprises an outer diameter smaller than an outer diameter of the first diffuser stage.
6. The compressor of claim 1 , wherein the first diffuser stage comprises a first anti-rotation projection and/or recess for engaging a corresponding second anti-rotation recess and/or projection of the second diffuser stage.
7. The compressor of claim 1 , wherein the second diffuser stage comprises a greater number of diffuser blades than the first diffuser stage.
8. The compressor of claim 1 , wherein diffuser blade inlet angles vary between the first and second diffuser stages.
9. The compressor of claim 1 , wherein diffuser blade outlet angles vary between the first and second diffuser stages.
10. The compressor of claim 1 , wherein the first diffuser stage comprises a diffuser blade outlet angle which is smaller than a diffuser blade inlet angle of the second diffuser stage.
11. The compressor of claim 1 , wherein the second diffuser stage comprises a stagger angle which is smaller than a stagger angle of the first diffuser stage.
12. The compressor of claim 1 , wherein a maximum diffuser blade thickness of the first diffuser stage is greater than a maximum diffuser blade thickness of the second diffuser stage.
13. The compressor of claim 1 , wherein the second diffuser stage comprises a diffuser blade chord length smaller than a diffuser blade chord length of the first diffuser stage.
14. The compressor of claim 1 , wherein the second diffuser stage comprises a greater diffuser blade solidity than the first diffuser stage.
15. The compressor of claim 1 , wherein the impeller comprises a mixed flow impeller.
16. The compressor of claim 1 , wherein the diffuser assembly comprises a third diffuser stage, the second diffuser stage is located downstream of the first diffuser stage, and the third diffuser stage is located downstream of the second diffuser stage.
17. A vacuum cleaner comprising the compressor of claim 1 .
18. A diffuser assembly for a compressor, the diffuser assembly comprising a first diffuser stage and a second diffuser stage, wherein the first and second diffuser stages comprise separate components connected to one another by a fastener;
wherein the first diffuser stage comprises a first hub, a first outer wall, and a first plurality of diffuser blades extending between the first hub and the first outer wall, and the second diffuser stage comprises a second hub, a second outer wall, and a second plurality of diffuser blades extending between the second hub and the second outer wall; and
wherein the fastener extends between the first and second hubs at a location remote from an outer diameter of the first and the second hubs, such that the fastener is removed from the common flow path.