Furnace distribution blower without a blower housing
A furnace distribution blower for use in a conventional furnace that is configured without a blower housing. The furnace distribution blower includes a backward curved impeller mounted around a drive motor having a central drive shaft. The drive motor rotates the backward curved impeller to draw air into the inlet of the impeller. Preferably, the inlet of the impeller is closely mounted to an inlet bell of the furnace. The furnace distribution blower can be mounted to a support tray such that the furnace distribution blower can be moved from an operating position in which the impeller is positioned beneath the heat exchanger and a service position in which the impeller is removed from within the furnace housing. The elimination of the blower housing decreases the cost of the furnace distribution blower as compared to a blower having a housing.
The present application is based on and claims priority to U.S. Provisional Patent Application Ser. No. 60/528,124, filed on Dec. 9, 2003 and U.S. Provisional Patent Application Ser. No. 60/545,183, filed on Feb. 17, 2004.
BACKGROUND OF THE INVENTIONThe present invention generally relates to a furnace, and particularly to a furnace distribution blower used within the furnace. More specifically, the present invention relates to a unique configuration and mounting for a furnace distribution blower that does not include a blower housing surrounding a rotating impeller that creates a flow of air over the furnace heat exchanger.
Typically, a household furnace includes a furnace distribution blower that draws a supply of fresh air into the furnace housing and directs the flow of fresh air over a heat exchanger. The heated air, after passing over the heat exchanger, is directed to the environment to be heated.
In typical prior art furnaces, the furnace distribution blower includes a blower housing that surrounds a forward curved impeller wheel. The blower housing includes an inlet opening that receives the flow of fresh air. The rotating forward curved impeller directs the fresh air radially outward against a scroll shaped housing, which ultimately directs the flow of air out of an outlet formed in the housing and over the heat exchanger of the furnace. In this type of system, the impeller for the furnace distribution blower is positioned in the center of the housing such that the flow of fresh air is directed by the housing.
One disadvantage of the prior art furnace distribution blower is the cost and materials required for the housing. Typically, the housing is formed from either a metallic or plastic material that must be separately formed and assembled.
Therefore, it is an object of the present invention to provide a furnace distribution blower that does not include a housing yet provides the required airflow characteristics for proper operation of the furnace.
SUMMARY OF THE INVENTIONThe present invention utilizes a backward curved impeller mounted on a vertical motor shaft of a drive motor. The backward curved impeller surrounds the drive motor including the vertical motor shaft. The drive motor preferably includes a plurality of brackets that mount the motor to a bell-shaped inlet plate of the furnace housing to draw air into the impeller from the bottom portion of the furnace. The bell-shaped portion of the inlet plate is generally the same size as the inlet of the impeller and is designed to be close vertically to the inlet of the impeller so that pressurized air in the furnace will not escape back through the inlet bell.
The impeller of distribution blower draws air through the cool air inlet of the furnace, over the drive motor and moves the cool air across the heat exchanger. The inlet air flow, now warmed by the heat exchanger, is exhausted from the top of the furnace.
In one embodiment of the invention, the inlet of the backward curved impeller is mounted slightly above the bottom wall of the furnace housing such that cool air can be received from the bottom of the furnace. Alternatively, the impeller can be rotated 90° and mounted to one of the sidewalls of the furnace housing such that inlet air is received from next to the furnace housing. In yet another alternate embodiment of the invention, the impeller can be suspended above the bottom wall of the furnace housing such that the flow of cool air can be received from both the bottom and the sides of the furnace housing.
In yet another alternate embodiment of the invention, the rotating backward curved impeller can be spaced from the bottom wall of the furnace housing and surrounded by a scroll-shaped outer wall. The scroll-shaped outer wall increases the efficiency of the rotating backward curved impeller by directing the air flow upward toward the heat exchanger without the use of a housing. The outer wall allows the inlet air to be drawn from both the side and the bottom wall of the furnace housing.
In yet another alternate embodiment of the invention, the rotating backward curved impeller is spaced above the bottom wall of the furnace within a scroll-shaped support tray. The support tray is formed from stamped metal and is supported beneath the heat exchanger and is movable relative to the furnace housing. The support tray includes a scroll-shaped outer wall. The scroll-shaped outer wall directs the flow of air upward from the impeller toward the heat exchanger of the furnace and increases the efficiency of the rotating backward curved impeller without the use of a housing.
BRIEF DESCRIPTION OF THE DRAWINGSThe drawings illustrate the best mode presently contemplated of carrying out the invention.
In the drawings:
The furnace distribution blower 14 creates a flow of air 31 that passes over the heat exchanger 16 and flows to the environment to be heated, as illustrated by arrow 32.
In prior art furnace configurations, the furnace distribution blower is typically a blower having a blower housing with an inlet and an outlet and a drive motor for rotating a forward curved (FWC) inlet wheel. The forward curved inlet wheel draws fresh air from outside of the furnace housing 12 and directs the flow of air over the heat exchanger 16. Typically, the distribution blower includes an external housing that is formed from either a molded plastic material or metal and encloses the rotating forward curved wheel to create the desired flow of air through the furnace.
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The impeller 34 includes an inlet 50 having a diameter defined by a top lip 52. The top lip 52 of the impeller 34 is spaced slightly inward from an inlet bell 54 formed as a portion of the bottom wall 56 of the furnace housing 12. As illustrated, the close spacing between the top lip 52 of the impeller 34 and the inlet bell 54 prevents pressurized air within the furnace interior 58 from escaping back through the inlet.
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The open topped scroll created by the sidewall 78 can also be created to increase the airflow upward toward the heat exchanger 16 of the furnace. As illustrated in
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As can be understood in the drawings, the scroll-shape of the support tray has the advantage of increasing the efficiency of the backward curved impeller 34 while creating room along the sides and bottom to allow air to be drawn into the support tray. Further, the open top of the support tray allows the support tray to be slid into and out of the furnace housing, as clearly illustrated.
In the preferred embodiment of the invention, each of the support trays is formed from a single piece of stamped sheet metal formed on a large press. However, it is contemplated that the support trays could be formed from other materials while operating within the scope of the present invention.
Although not shown in the Figures, it is contemplated that the furnace distribution blower could be configured as two backward curved impellers mounted back-to-back and having a horizontal drive motor mounted in one of the wheel inlets. The motor would be mounted to a bracket to provide an inlet area and have a shaft passing through both of the impellers such that inlet air could be drawn in from both sides of furnace housing.
Various alternatives and embodiments are contemplated as being within the scope of the following claims particularly pointing out and distinctly claiming the subject matter regarded as the invention.
Claims
1. A furnace distribution blower comprising:
- a drive motor having a drive shaft; and
- an impeller having an inlet surrounding the drive motor, the drive motor being operable to rotate the impeller around the drive motor to draw a flow of air into the inlet of the impeller such that the impeller radially discharges the inlet air,
- wherein the impeller is not surrounded by a housing.
2. The furnace distribution blower of claim 1 wherein the drive motor is mounted above an inlet opening of a furnace by a plurality of mounting arms.
3. The furnace distribution blower of claim 2 wherein the inlet of the impeller is closely spaced from an inlet bell of the furnace that defines the inlet opening of the furnace.
4. The furnace distribution blower of claim 1 wherein the impeller is a backward curved impeller having a plurality of backward curved impeller blades.
5. The furnace distribution blower of claim 4 wherein the inner blade tips of each impeller blade are spaced from the drive motor such that the impeller is rotatable about the drive motor.
6. The furnace distribution blower of claim 1 wherein the impeller is mounted to a sidewall of the furnace.
7. The furnace distribution blower of claim 1 wherein the impeller is mounted to a support wall spaced from the bottom wall of the furnace.
8. A furnace distribution blower for use in a furnace having a furnace enclosure including a pair of spaced sidewalls and a bottom wall, the distribution blower comprising:
- a drive motor having a drive shaft;
- an impeller having an inlet surrounding the drive motor, the drive motor being operable to rotate the impeller around the drive motor to draw a flow of air into the inlet of the impeller such that the impeller radially discharges the inlet air, wherein the impeller is not surrounded by a housing; and
- a scroll-shaped outer wall surrounding the impeller, wherein the scroll-shaped outer wall has an open upper end and directs the flow of air from the impeller into the furnace enclosure
9. The furnace distribution blower of claim 8 further comprising a support wall spaced above the bottom wall of the furnace enclosure, the support wall including an inlet bell aligned with the inlet of the impeller.
10. A furnace distribution blower for use in a furnace having a heat exchanger and a support frame, the blower comprising:
- a drive motor having a drive shaft;
- an impeller having an inlet surrounding the drive motor, the drive motor being operable to rotate the impeller around the drive motor to draw a flow of air into the inlet of the impeller such that the impeller radially discharges the inlet air; and
- a support tray positioned below the heat exchanger of the furnace and surrounding the impeller, the support tray including an inlet bell and a scroll-shaped outer wall to direct the flow of air from the impeller toward the heat exchanger.
11. The furnace distribution blower of claim 10 wherein the drive motor is mounted above the inlet bell formed in the support tray by a plurality of mounting arms.
12. The furnace distribution blower of claim 11 wherein the inlet of the impeller is closely spaced from the inlet bell of the support tray.
13. The furnace distribution blower of claim 10 wherein the impeller is a backward curved impeller having a plurality of backward curved impeller blades.
14. The furnace distribution blower of claim 13 wherein the inner blade tips of each impeller blade are spaced from the drive motor such that the impeller is rotatable about the drive motor.
15. The furnace distribution blower of claim 10 wherein the support tray is movable along the support frame of the furnace.
16. The furnace distribution blower of claim 15 wherein the support tray is movable between an operating position in which the impeller is positioned beneath the heat exchanger and a service position in which the impeller is removed from beneath the heat exchanger.
17. The furnace distribution blower of claim 15 wherein the support tray is formed from stamped metal.
18. The furnace distribution blower of claim 10 wherein the support tray includes an angled bottom wall, wherein the drive motor and impeller are mounted to the angled bottom wall such that the impeller is positioned at an angle relative to horizontal when the impeller is positioned beneath the heat exchanger.
19. The furnace distribution blower of claim 10 wherein the support tray includes a pair of spaced side edges that are slidably movable along the support frame of the furnace such that the support tray can be moved from an operating position in which the impeller is positioned beneath the heat exchanger and a service position in which the impeller is removed from the beneath the heat exchanger.
20. The furnace distribution blower of claim 10 wherein the support tray includes a scroll-shaped side wall that directs the flow of air from the impeller upward toward an outlet of the support tray.
Type: Application
Filed: Dec 6, 2004
Publication Date: Sep 8, 2005
Inventors: Frederick Paulsen (Holiday Island, AR), Steven Post (Cassville, MO), John Platz (Springfield, MO)
Application Number: 11/005,541