US20180066667A1

US20180066667A1 - Low aspect ratio fan

Info

Publication number: US20180066667A1
Application number: US15/695,500
Authority: US
Inventors: Edward K. Boyd
Original assignee: Macroair Technologies Inc
Current assignee: Macroair Technologies Inc
Priority date: 2016-09-06
Filing date: 2017-09-05
Publication date: 2018-03-08

Abstract

A fan with a housing a front face, a back face, and a side portion extending between and securing together the front face and the back face, and a duct extending from a top portion of the housing for directing air flow. The fan further includes a rotor secured within the housing, the rotor comprising a motor housing and a plurality of arcuate blades, wherein the motor housing comprises a plurality of interlocking recesses formed therein and one end of each of the plurality of blades comprises an interlocking pin, wherein the interlocking pin is received into a respective interlocking recess in the motor housing for securing the blade to the motor housing. Air is received into an inlet formed into the front face of the housing and circulated over the motor and the blades for cooling an area.

Description

RELATED APPLICATION

This application claims the benefit of priority of U.S. Provisional Application No. 62/383,663 filed Sep. 6, 2016.

FIELD

The invention disclosed herein is related to fans, and in particular, low aspect ratio fans for use in rooms and structures with space limitations.

BACKGROUND

Typical ceiling fans are generally mounted proximate the ceiling and have a relatively large blade diameter. In general, the greater the diameter of the fan, the larger the volume of air that the fan is able to move. There are several problems that exist with the use of typical ceiling fans in areas of limited space. One problem with typical ceiling fans is the requirement of a space above the fan blades which allow air flow into the fan from above. Additionally, because of the exposed rotating fan blades, there is a minimum height requirement to ensure the safety of those in proximity to the fan. Ceiling fans are thus best suited for large, mostly open spaces with ceilings that meet the minimum height requirements to ensure that the fan has enough space to receive air flow from above while maintaining the safety of those in the room with the fan.
In areas with limited space, such as a shallow mezzanine packing area with workers present, or a trailer that is pulled up to a loading dock with forklift access, or a room with low ceilings, it can be difficult to provide air movement, especially with the problems presented by typical ceiling fans. A fan having a large diameter and shallow profile that does not require space between the fan blades and the ceiling, or a minimum safety clearance, is desirable.

SUMMARY

Disclosed herein is a fan comprising a housing having a front face, a back face, and a side portion extending between and securing together the front face and the back face, and a duct extending from a top portion of the housing for directing air flow. A rotor is secured within the housing, and includes a motor housing and a plurality of blades. The motor housing has a plurality of interlocking recesses formed therein, and one end of each of the plurality of blades comprises an interlocking pin. The interlocking pin is received into a respective interlocking recess in the motor housing for securing the blade to the motor housing. In use, air is received into an inlet formed into the front face of the housing and faned over the motor and the blades for cooling an area. The ratio of the diameter of the rotor to the depth of the rotor is at least 3.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a front perspective view of a centrifugal fan according to one embodiment of the invention;

FIG. 2 shows a close up side view of the centrifugal fan of FIG. 1;

FIG. 3 shows a close up front view of the inlet of the centrifugal fan of FIG. 1;

FIG. 4A shows a front view of the rotor without the housing according to one aspect of the invention; and

FIG. 4B shows the rotor in combination with the housing according to another aspect of the invention.

DETAILED DESCRIPTION

Embodiments of centrifugal fans designed for use in areas of limited space are described herein. FIGS. 1-3 depict an exemplary centrifugal fan 100 according to one embodiment of the invention. The fan 100 includes a housing 105. The housing 105 may include a front face 110 and a back face 115 with a side portion 120 extending between and securing together the front and back faces 110 and 115. The front and back face may have a U-shaped configuration, for example. A duct 130 may extend from the top of the “U” for exhausting air out of the fan 100. An air exhaust port may exist on a single side, or multiple sides, depending upon the particular needs of the user.
The front face 110 of the housing may be equipped with an inlet opening 140 for receiving air into the fan 100. A rotor 150, described below, may pull air from the central inlet 140 over the motor and the blades for cooling an area. The air may also be drawn over the motor, thereby preventing the motor from overheating.
The housing 105 may be manufactured from any acceptable material, including plastic, metal or a synthetic material. Moreover, the inlet 140 of the housing 110 may optionally be fitted with an air filter. The air filter may be useful for filtering the air flowing into the rotor by removing particulate matter from the air flowing into the workspace. The filtered air may also help to keep the blades clean for optimal fan performance. Finally, the filter may also serve to keep foreign objects from contacting the rotor.
The rotor 150, best illustrated by FIGS. 4A and 4B, may be configured to be located inside the housing 105. The rotor 150 may include a motor housing 155, and a set of blades 160 extending from the motor housing 155. The rotor 150 may be manufactured using an extrusion process, wherein a plurality of interlocking recesses may be formed into the motor housing 155 and the end of the blades 160 that attach to the motor housing 155 include interlocking pins. For example, the interlocking recesses and pins formed into the motor housing 155 and the blades 160, respectively, may be in the shape of a dovetail. To attach the blades 160 to the motor housing 155, the blades 160 may be pressed into the interlocking recesses in the motor housing 155. A device, such as a pin, spring loaded ball bearing, or other locking mechanism may additionally be included to prevent the blades 160 from separating from the motor housing 155. Fan blades 160 in a preferred embodiment extend outwardly from the motor housing 155 in a curved or arcuate fashion. The blades preferably extend with an arc that is consistent for each set of fan blades. The arc of each set of fan blades may range from 20 to 45 degrees depending upon the specific operational characteristics desired for the specific fan.
It shall be understood that the rotor 150 may additionally, or alternately, be functional without the housing 110 (FIG. 4A). In situations in which the rotor is provided without the housing, air from the fan may be dispersed in a 360-degree pattern.
Unlike most centrifugal fans, because the blades 160 are secured to the motor housing 155 via the interlocking recesses and pins, a back plate on the impeller 150 (or rotor) is not required in order to keep the blades 160 secured to the motor housing 155. This allows blades 160 to be added and/or removed to the motor housing 155 easily without the need for expensive tooling or alternative motor housings. For example, it may be desirable to change out the blades 160 with larger (or smaller) blades to give the fan a larger (or smaller) diameter. The blades 160 that are attached to the motor housing 155 may be easily removed by sliding the blades 160 out from the respective interlocking recesses, and replacing the blades 160 with new blades 160 having the desired size and/or shape. In this way, the load and performance of the fan 100 may be varied.
The interlocking system described above ensures a secure connection between the motor housing 155 and the blades 160. However, it also allows for the blades 160 to be manufactured separately from the motor housing 155. This is important for the reasons described above, as well as because an extruded rotor 150 that includes the motor housing 155 and the blades 160 as a single piece may be cumbersome to manufacture and/or handle.
The fan 100 may be configured to have an aspect ratio of at least 3, more preferably 4, and most preferably 5 or greater. The aspect ratio of the fan 100 is defined as the ratio of the diameter of the rotor 150 to the depth of the rotor 150. Most centrifugal fans are very deep and have a small diameter, yielding a low aspect ratio. For example, a prior art centrifugal fan may have a diameter of 6 inches with a 12 inch depth. Thus, the aspect ratio of the prior art fan is ½.
Conversely, the fan described herein may be very shallow with a large diameter. In one embodiment of the invention, the fan 100 has a diameter of 25 inches and a 5 inch depth, yielding an aspect ratio of 5. A higher aspect ratio allows a fan to move considerable air in a room while consuming little space near the ceiling of the structure.
The fan 100 may be equipped with a high-torque, low-speed motor 170 that has a low-profile capable of being received into the middle of the motor housing. The motor 170 may, for example, be configured to operate in the range of from 10 to 500 rpm and generate a constant torque of no less than 13 NM.
The fan 100 may be optionally mounted to a stand 200 such that the fan 100 may be easily moved from one area to another. Additionally, or alternately, the fan housing 105 may include a bracket 125 for securing the housing 105 to structure.
Many different arrangements of the various components depicted, as well as components not shown, are possible without departing from the spirit and scope of the present invention. Embodiments of the present invention have been described with the intent to be illustrative rather than restrictive. Alternative embodiments will become apparent to those skilled in the art that do not depart from its scope. A skilled artisan may develop alternative means of implementing the aforementioned improvements without departing from the scope of the present invention. It will be understood that certain features and subcombinations are of utility and may be employed without reference to other features and subcombinations and are contemplated within the scope of the present invention.

Claims

1. A fan comprising:

a housing having a front face, a back face, and a side portion extending between and securing together the front face and the back face, and a duct extending from a top portion of the housing for directing air flow; and

a rotor secured within the housing, the rotor comprising a motor housing and a plurality of arcuate blades, wherein the motor housing comprises a plurality of interlocking recesses formed therein and one end of each of the plurality of blades comprises an interlocking pin, wherein the interlocking pin is received into a respective interlocking recess in the motor housing for securing the blade to the motor housing;

wherein:

air is received into an inlet formed into the front face of the housing and circulated over the motor and the blades for cooling an area; and the fan has aspect ratio of at least 3.

2. The fan of claim 1, wherein the fan has an aspect ratio of at least 4.

3. The fan of claim 1, wherein the fan is equipped with a motor configured to operate in the range of from 10 to 500 rotations per minute and generate a constant torque of at least 13 NM.

4. The fan of claim 1, wherein the blades extend outwardly and arcuately from the motor housing with an arc in the range of from 25 to 40 degrees.