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US 2021/0196912 A1Published application
Fan unit with improved surge characteristics
AssigneeFisher & Paykel Healthcare Limited
InventorJohannes Nicolaas Bothma
Life of this patent
Estimating the term…
Abstract
A fan unit that forms part of a gases supply unit used as part of a breathing assistance system for providing heated gases to a user. The fan has an impeller surrounded by an upwardly sloped surface to facilitate improved airflow performance under surge conditions.
Claims24
(canceled)
A fan unit comprising:
- a casing defining a diffuser, a volute, an inlet, and an outlet;
- an impeller comprising an inducer and an exducer;
- a recirculation passage defined by the casing to provide a gases flow path such that the recirculation passage is in fluid communication with both the exducer and the inducer, wherein a portion of gases exiting the impeller recirculates in the recirculation passage from the exducer to the inducer;
- and
- a flow directing surface sloping upward at an angle of up to 6 degrees from a plane perpendicular to the axis of a rotation of the impeller.
2 more elements
A fan unit comprising:
- a casing comprising:
- a diffuser,
- a volute defined by a channel,
- an inlet, and
- an outlet;
- an impeller located within the casing and configured to be connected to a motor, the impeller further comprising an inducer configured to receive a flow of gases from the inlet, the diffuser positioned at least partially annular to the impeller, and the impeller further having an exducer configured to expel the flow of gases to the diffuser and the volute;
- a recirculation passage providing a gases flow path between the exducer and the inducer;
- and
- a wedge member configured to partially encircle at least a portion of the exducer, wherein the wedge member is configured to direct the flow of gases exiting the impeller at least partially toward a direction of airflow re-entering the diffuser from the volute.
6 more elements
A fan unit comprising:
- a casing defining:
- a diffuser,
- a volute defined by a channel,
- an inlet, and
- an outlet;
- an impeller located within the casing, the impeller adapted to connect to a motor configured to rotated about an axis of the impeller;
- wherein the impeller comprises an entry to receive gases from the inlet of the casing and an exit to expel gases to the diffuser, the volute, and the outlet of the casing;
- a recirculation passage providing a gases flow path from an area proximate the exit of the impeller to the entry of the impeller;
- and
- a wedge member configured to partially encircle at least a portion of the impeller, wherein the wedge member is configured to direct a flow of gases exiting the impeller at least partially toward a direction of airflow re-entering the diffuser from the volute.
7 more elements
Dependencies are inferred from the claim text.