US20190041073A1

US20190041073A1 - Air flow capture system

Info

Publication number: US20190041073A1
Application number: US15/667,457
Authority: US
Inventors: Perry Lynn Martens
Original assignee: Individual
Current assignee: Individual
Priority date: 2017-08-02
Filing date: 2017-08-02
Publication date: 2019-02-07

Abstract

An apparatus and kit for capturing airflow from an inlet of a centrifugal fan, the centrifugal fan having a housing containing an impeller rotatable about a fan axis and an inlet passing through the housing along the centrifugal fan axis, the apparatus comprising a frame securable to the centrifugal fan housing across the centrifugal fan inlet and a capture fan rotatably supported by the frame, the capture fan having a center of rotation about the centrifugal fan axis. The apparatus further comprises an electrical generator motor operably connected to and drive by rotation of the capture fan, wherein the capture fan is rotatable in a first direction about the centrifugal fan axis by air drawn into the centrifugal fan inlet during operation of the centrifugal fan. The kit further comprises a centrifugal fan.

Description

BACKGROUND OF THE INVENTION

1. Field of Invention

The present invention relates generally to the field of energy capture systems, and in particular to an air flow energy capture system.

2. Description of Related Art

Furnace and air circulation systems most commonly employ centrifugal fans, also known as squirrel cage fans or blowers, to draw air into the system and to move the air through at a constant speed. Air is drawn into the fan through an inlet in the side of the housing, then turns 90 degrees and is accelerated with centrifugal force as it passes over the fan blades and exits the fan through an outlet in the housing. As air is drawn into the fan through the inlet, the air increases in speed, creating a draft at the inlet, both within and outside of the fan housing.

SUMMARY OF THE INVENTION

According to a first embodiment of the present invention there is disclosed a apparatus for capturing airflow from an inlet of a fan the apparatus comprising a capture fan located upstream of the centrifugal fan and an electrical generator motor operably connected to and drive by rotation of the capture fan wherein the capture fan is rotatable in a first direction by air drawn into the fan inlet during operation of the fan. The capture fan may be located in a cabinet wall surrounding the fan.
The fan may comprise a centrifugal fan, the centrifugal fan having a housing containing an impeller rotatable about a fan axis and an inlet passing through the housing along the centrifugal fan axis, the apparatus may further comprise a frame securable to the centrifugal fan housing across the centrifugal fan inlet. The capture fan may be rotatably supported by the frame wherein the capture fan has a center of rotation about the centrifugal fan axis and wherein the capture fan may be rotatable in a first direction about the centrifugal fan axis by air drawn into the centrifugal fan inlet during operation of the centrifugal fan.
The capture fan may comprise an axial fan having a central hub and a plurality of fan blades extending radially therefrom. The plurality of fan blades of the axial fan may comprise radial fan blades extending radially outward from the hub to a tip region. Each of the plurality of fan blades may have a leading and a trailing edge. The leading edge may be convex. The trailing edge may be concave. The tip region of the radial fan blades may be secured to a cylindrical outer band. Each of the plurality of fan blades may be skewed rearwardly from the leading edge to the trailing edge.
According to a further embodiment of the present invention there is disclosed a fan system for capturing airflow comprising a powered fan, a capture fan located upstream of the powered fan and an electrical generator motor operably connected to and drive by rotation of the capture fan wherein the capture fan is rotatable in a first direction by air drawn into the fan inlet during operation of the powered fan. The capture fan is located within a cabinet wall of a cabinet containing the powered fan.
The powered fan may comprise a centrifugal fan having a centrifugal fan housing wherein the fan system may further comprise a frame adapted to span an inlet in the centrifugal fan housing and securable to the centrifugal fan housing. The capture fan may have a center of rotation about a capture fan axis at the capture fan center, the capture fan rotatably mounted to the frame wherein the capture fan may be rotatable in a first direction about the capture fan axis by air drawn into the inlet during operation of the centrifugal fan.
The capture fan may comprise an axial fan having a hub at the capture fan center and a plurality of fan blades. The plurality of fan blades of the axial fan may comprise radial fan blades extending radially outward from the hub to a tip region. The tip region of the radial fan blades may be secured to a cylindrical outer band.
Other aspects and features of the present invention will become apparent to those ordinarily skilled in the art upon review of the following description of specific embodiments of the invention in conjunction with the accompanying figures.

BRIEF DESCRIPTION OF THE DRAWINGS

In drawings which illustrate embodiments of the invention wherein similar characters of reference denote corresponding parts in each view,

FIG. 1 is a perspective view of an airflow capture system installed on a centrifugal fan according to a first embodiment of the present invention.

FIG. 2 is an exploded view of the airflow capture system of FIG. 1.

FIG. 3 is a top view of an axial fan.

FIG. 4 is a perspective view of fan casing having an airflow capture system installed therein.

FIG. 5 is a perspective view of a capture fan for use in the system of FIG. 1 according to a further embodiment.

FIG. 6 is a plan view of the capture fan of FIG. 5.

DETAILED DESCRIPTION

Referring to FIGS. 1 and 2, an apparatus for capturing airflow from an inlet of a centrifugal fan according to a first embodiment of the invention is shown generally at 10. The apparatus 10 is mounted to a centrifugal fan 8 over an inlet 6, as will be set out below.
The apparatus 10 comprises an electrical generator motor 12 mounted to a frame 30 and coupled to an axial capture fan 50 along a central axis 100. The frame 30 is mounted to the centrifugal fan 8 over the inlet 6.
Referring to FIG. 2, the frame 30 comprises an L-bracket 32 mounted within a center ring portion 34 with a plurality of elongate support arms 36 extending radially outwards from the center ring portion 34 to distal ends 38. The L-bracket 32 and support arms 36 may be secured to the center ring portion 34 by any known means, such as, by way of non-limiting example, welding. The L-bracket 32 may include a plurality of mounting holes 40 therethrough along spaced apart axes perpendicular to the central axis 100, adapted to allow the electrical generator motor 12 to be mounted thereto, as will be further set out below.
As illustrated, four support arms 36 extend in an x-shape from the center ring portion 34, although it will be appreciated that more or less support arms 36 may be useful, as well. A mounting hole 42 extends along an axis spaced apart and parallel to the central axis 100 through each support arm 36 proximate to the distal end 38. The length of the support arms 36 is selected such that the frame 30 spans across the inlet 6 of the centrifugal fan 8 with the mounting holes 42 aligned with matching mounting holes 44 on the centrifugal fan 8.
The electrical generator motor 12 includes mounting feet 14, as illustrated in FIG. 2. A driveshaft 16 with external threading 18 thereon extends outwards from the center of the electrical generator motor 12 along a driveshaft axis 102. The mounting feet 14 are secured to the frame 30 by any means as is commonly known, such as, by way of non-limiting example, a plurality of welds, nuts and/or bolts through the mounting holes 40. In the mounted position, the driveshaft axis 102 and central axis 100 are aligned such that the driveshaft 16 extends along the central axis 100. As is commonly known in the art, the electrical generator motor 12 includes a generator wire 20 extending therefrom, through which electrical power is supplied to other sources, such as, by way of non-limiting example, a charge controller 22 or rectifier.
Turning to FIGS. 2 and 3, the axial capture fan 50, extending between a front and rear, 80 and 82, respectively, comprises a central circular hub 52 with a plurality of fan blades 54 and a cylindrical outer ring 56. As best seen on FIG. 2, the hub 52 includes a central circular portion 70 at the front 80 with a cylindrical wall portion 72 extending axially from the central circular portion 70 at the front 80 to the rear 82, along the central axis 100. The hub 52 includes an aperture 58 extending through the circular portion 70 at the center to allow the driveshaft 16 to extend therethrough for rotation about the central axis 100 in a first rotation direction 104. The outer ring 56 encloses the fan blades 54 and is generally centered on the central axis 100.
Each fan blade 54 extends radially between a root region 60 secured to the cylindrical wall portion 72 of the hub 52 and a tip region 62 secured to the outer ring 56. The fan blades 54 are joined to the cylindrical wall portion 72 of the hub 52 at the root region 60 over the full width of each blade and are joined to the outer ring 56 at the tip region 62 over the full width of each blade. Each fan blade 54 includes a convex leading edge 64 and a concave trailing edge 66. As best seen in FIG. 2, the leading edge 64 at the root region 60 is secured to the cylindrical wall portion 72 proximate to the front 80 of the fan, with the root region 60 skewed rearwardly such that the trailing edge 66 is secured to the cylindrical wall portion 72 proximate to the rear 82 of the fan. Similarly, the tip region 62 of each fan blade 54 is secured to the outer ring 56 such that the leading edge 64 is proximate to the front 80 of the fan and the trailing edge 66 is proximate to the rear 82 of the fan. This style of fan design is commonly known and often used in the automotive industry for cooling purposes.
To assemble the apparatus 10, the electrical generator motor 12 is secured to the frame 30 as outlined above. The frame 30 is secured to the centrifugal fan 8 with fasteners 98 through the mounting holes 42 and 44. The fasteners 98 may be of any suitable type, such as, by way of non-limiting example, screws or nuts and bolts. A threaded coupling 90 with internal threading adapted to engage the external threading 18 on the driveshaft 16 is coupled to the driveshaft 16 and to a fastener 92 through the aperture 58 in the axial capture fan 50, thereby securing the axial capture fan 50 to the driveshaft 16 of the electrical generator motor 12. The fastener 92 includes external threading 94 adapted to engage with the internal threading of the treading coupling 90 and includes a head portion 96 sized to span the aperture 58 and engage upon the circular portion 70 of the hub 52.
Referring to FIG. 1, when the centrifugal fan 8 is in operation, air is pulled into the inlet 6 of the centrifugal fan 8 in a direction generally indicated at 106. As air is pulled into the centrifugal fan 8, the axial capture fan 50 rotates in the first rotation direction 104, thereby rotating the driveshaft 16 of the electrical generator motor 12 and producing electrical power.
Turning now to FIG. 4, alternatively, the capture fan 50 may be located in a cabinet wall 202 of a fan cabinet containing the centrifugal fans 8. As illustrated in FIG. 4, cabinet 200 may contain more than one centrifugal fan 8 and more than one capture fan 50. It will be appreciated that the cabinet 200 may include an access port 204 covered by a door which is not illustrated in FIG. 4 so as to illustrate the interior of the cabinet 200.
Turning now to FIGS. 5 and 6, an illustration of a second side of a capture fan 300 for use in the present system according to a further embodiment is illustrated. As depicted, the capture fan includes a hub 302 having a hub channel 304 extending therethrough and a fan blade assembly housing 306. The fan blade assembly housing 306 may be secured to the hub 302 with bolts 308 or the like as are commonly known.
In some embodiments, the fan blade assembly housing 306 has an inner diameter 320 of about 6 inches. In some embodiments, the fan blade assembly housing 306 has an inner diameter 320 between about 4 inches and 8 inches. In some embodiments, a fan hub 302 has a diameter 330 of about 11 inches. In some embodiments, a fan hub 302 has a diameter 330 between about 8 inches and 20 inches. In some embodiments, the width 340 of the plurality of first fan blades 310 is about 5⅞ inches. In some embodiments, the width 314 of the plurality of first fan blades 122 is between about 4 inches 10 inches. In some embodiments, the first fan blade assembly 300 has a diameter 350 of about 23 inches. In some embodiments, the first fan blade assembly 300 has a diameter 350 between about 18 inches and 24 inches.
As illustrated, the first side of a first fan blade assembly 300 has a clockwise rotation of 322, and each first fan blades 310 has a fan blade tailing edge 312 and a fan blade leading edge 314 with a pitch angle of about 40 degrees and 9 fan blades. In some embodiments, each fan blades 310 has a fan blade tailing edge 312 and a fan blade leading edge 314 with a pitch angle between about 20 degrees and 60 degrees and between about 4 and 20 first fan blades. In some embodiments, the vertical between the fan blade tailing edge 312 and the fan blade leading edge 314 is about 2¼ inches. In some embodiments, the vertical between the fan blade tailing edge 312 and the fan blade leading edge 314 is between about 1½ inches and 10 inches. The fan blade assembly 300 may be selected to be an automotive radiator cooling fan.
While specific embodiments of the invention have been described and illustrated, such embodiments should be considered illustrative of the invention only and not as limiting the invention as construed in accordance with the accompanying claims.

Claims

What is claimed is:

1. An apparatus for capturing airflow from an inlet of a fan the apparatus comprising:

a capture fan located upstream of said centrifugal fan,

an electrical generator motor operably connected to and drive by rotation of said capture fan;

wherein said capture fan is rotatable in a first direction by air drawn into said fan inlet during operation of said fan.

2. The apparatus of claim 1 wherein said capture fan is located in a cabinet wall surrounding said fan.

3. The apparatus of claim 1 wherein said fan comprises a centrifugal fan, the centrifugal fan having a housing containing an impeller rotatable about a fan axis and an inlet passing through the housing along the centrifugal fan axis, the apparatus further comprising:

a frame securable to said centrifugal fan housing across said centrifugal fan inlet,

wherein said capture fan is rotatably supported by said frame, said capture fan having a center of rotation about the centrifugal fan axis; and

wherein said capture fan is rotatable in a first direction about said centrifugal fan axis by air drawn into said centrifugal fan inlet during operation of said centrifugal fan.

4. The apparatus of claim 3 wherein said capture fan comprises an axial fan having a central hub and a plurality of fan blades extending radially therefrom.

5. The apparatus of claim 4 wherein said plurality of fan blades of said axial fan comprise radial fan blades extending radially outward from said hub to a tip region.

6. The apparatus of claim 5 wherein each of said plurality of fan blades has a leading and a trailing edge.

7. The apparatus of claim 6 wherein said leading edge is convex.

8. The apparatus of claim 6 wherein said trailing edge is concave.

9. The apparatus of claim 5 wherein said tip region of said radial fan blades are secured to a cylindrical outer band.

10. The apparatus of claim 4 wherein each of said plurality of fan blades is skewed rearwardly from said leading edge to said trailing edge.

11. A fan system for capturing airflow comprising:

a powered fan;

a capture fan located upstream of said powered fan,

wherein said capture fan is rotatable in a first direction by air drawn into said fan inlet during operation of said powered fan.

12. The fan system of claim 11 wherein said capture fan is located within a cabinet wall of a cabinet containing said powered fan.

13. The fan system of claim 11 wherein said powered fan comprises a centrifugal fan having a centrifugal fan housing, the fan system further comprising:

a frame adapted to span an inlet in said centrifugal fan housing and securable to said centrifugal fan housing,

wherein said capture fan has a center of rotation about a capture fan axis at the capture fan center, said capture fan rotatably mounted to said frame.

wherein said capture fan is rotatable in a first direction about said capture fan axis by air drawn into said inlet during operation of said centrifugal fan.

14. The apparatus of claim 13 wherein said capture fan comprises an axial fan having a hub at said capture fan center and a plurality of fan blades.

15. The apparatus of claim 14 wherein said plurality of fan blades of said axial fan comprise radial fan blades extending radially outward from said hub to a tip region.

16. The apparatus of claim 15 wherein said tip region of said radial fan blades are secured to a cylindrical outer band.