Inlet for axial fan

Patent metadata

Field	Value
Publication number	US-11226114-B2
Application number	US-201716099121-A
Country	US
Kind code	B2
Filing date	May 3, 2017
Priority date	May 3, 2016
Publication date	Jan 18, 2022
Grant date	Jan 18, 2022

Abstract

A fan assembly ( 10 ) includes a shrouded fan rotor ( 18 ) having a plurality of fan blades ( 22 ) extending from a rotor hub ( 24 ) and rotatable about a central axis ( 20 ) of the fan assembly, and a fan shroud ( 26 ) extending circumferentially around the fan rotor ( 18 ) and secured to an outer tip diameter of the plurality of fan blades ( 22 ). A fan casing ( 16 ) encloses the shrouded fan rotor ( 18 ). The fan casing ( 16 ) defines a fan inlet ( 30 ) of the fan assembly and includes an inlet extension ( 54 ) at an outer diameter of the fan casing, extending axially upstream of a conventional bell mouth inlet ( 58 ), relative to a direction of airflow through the shrouded fan rotor ( 18 ).

First claim

The invention claimed is:

1. A fan assembly, comprising
a shrouded fan rotor:
a plurality of fan blades extending from a rotor hub and rotatable about a central axis of the fan assembly; and
a fan shroud extending circumferentially around the shrouded fan rotor and secured to an outer tip diameter of the plurality of fan blades; and
a fan casing enclosing the shrouded fan rotor, the fan casing defining a fan inlet of the fan assembly and including an inlet extension at an outer diameter of the fan casing, extending axially upstream of a bell mouth inlet, relative to a direction of airflow through the shrouded fan rotor;
wherein the inlet extension axially overlaps the fan shroud radially inboard of the fan shroud;
wherein the bell mouth inlet transitions to the inlet extension, the inlet extension including a convex portion and a concave portion; and
wherein the concave portion extends from an inlet extension leading edge axially to a transition point and the convex portion extends from the transition point to a rotor leading edge.

2. The fan assembly of claim 1 , wherein the convex portion axially overlaps the fan shroud.

3. The fan assembly of claim 1 , wherein the inlet extension tapers radially from the bell mouth inlet to an inlet extension leading edge at a taper angle.

4. The fan assembly of claim 3 , wherein the taper angle is between 0.5 degrees and 45 degrees.

5. The fan assembly of claim 1 , wherein a primary direction of airflow upstream of the inlet extension leading edge is transverse relative to the central axis.

6. A casing assembly for an axial fan, comprising
a fan casing extending circumferentially about a central axis, the fan casing defining a fan inlet of the axial fan; and
an inlet extension at an outer diameter of the fan casing, extending axially upstream of a bell mouth inlet, relative to a direction of airflow through a shrouded fan rotor disposed in the casing assembly;
wherein the inlet extension axially overlaps a fan shroud of the shrouded fan rotor radially inboard of the fan shroud;
wherein the bell mouth inlet transitions to the inlet extension, the inlet extension including a convex portion and a concave portion; and
wherein the concave portion extends from an inlet extension leading edge axially to a transition point and the convex portion extends from the transition point to a rotor leading edge of the shrouded fan rotor.

7. The casing assembly of claim 6 , wherein the inlet extension tapers radially from the bell mouth inlet to the inlet extension leading edge at a taper angle.

8. The casing assembly of claim 7 , wherein the taper angle is between 0.5 degrees and 45 degrees.

9. The casing assembly of claim 6 , wherein a primary direction of airflow upstream of the inlet extension leading edge is transverse relative to the central axis.

Assignees

• Carrier Corp

Inventors

• Dygert Ryan K

Classifications

• F04D29/667

  by influencing the flow pattern, e.g. suppression of turbulence · CPC title

• F04D29/541

  Specially adapted for elastic fluid pumps (F04D29/56 takes precedence) · CPC title

• F24F1/029 Primary

  characterised by the layout or mutual arrangement of components, e.g. of compressors or fans · CPC title

• F04D25/06

  the pump being electrically driven (F04D25/08 takes precedence) · CPC title

• F04D29/34

  Blade mountings {(for axial flow compressors F04D29/322)} · CPC title