US20090241587A1

US20090241587A1 - End ring of fan wheel of a fan coil unit including a flange

Info

Publication number: US20090241587A1
Application number: US12/405,501
Authority: US
Inventors: Yu Wang
Original assignee: Carrier Corp
Current assignee: Carrier Corp
Priority date: 2008-03-26
Filing date: 2009-03-17
Publication date: 2009-10-01

Abstract

A fan wheel of a blower fan includes a first base portion including a first flange, a second base portion including a second flange and a plurality of blades extending between the first base portion and the second base portion. The fan wheel is rotatable about an axis of rotation. A first end ring is attached to an inner perimeter of the first base portion, the first end ring including a third flange that extends outwardly relative to the axis of rotation. A second end ring is attached to an inner perimeter of the second base portion, the second end ring including a fourth flange that extends outwardly relative to the axis of rotation.

Description

REFERENCE TO RELATED APPLICATION

This application claims priority to U.S. Provisional Application No. 61/039,560 filed Mar. 26, 2008.

BACKGROUND OF THE INVENTION

This invention relates generally to a blower fan of a fan coil unit including a fan wheel having an end ring with an outwardly extending flange.
A fan coil unit includes a blower fan and a coil. Refrigerant flows through the coil, and the blower fan draws air over the coil. Heat is exchanged between the air drawn over the coil and the refrigerant flowing through the coil.
One example blower fan includes a fan wheel located in a housing. The housing includes an inlet orifice having an orifice diameter, and air is drawn into the housing through the inlet orifice. The fan wheel rotates about an axis of rotation and includes a plurality of blades that extend between two base portions integral with the blades. The plurality of blades define a wheel inner diameter and a wheel outer diameter. An end ring is attached to each of the base portions. In one prior blower fan, the end rings define an end ring outer diameter that is generally equal to the wheel outer diameter.
In another prior blower fan, the base portions integral with the blades each include a flange that extends outwardly and generally perpendicular to the axis of rotation of the fan wheel. An end ring is crimped around the outer perimeter of each of the flanges to define a u-shaped crimp, and a flange of the end ring extends inwardly towards the axis of rotation.
In another prior blower fan, the end rings of the blower fan have different sizes. In one example, the inner diameter of one of the end rings is greater than the outer diameter of the other of the end rings.
It is beneficial to make the inlet orifice of the housing and the end ring inner diameter as large as possible to increase the efficiency of the fan blower. However, a problem associated with increasing the end ring inner diameter is that the strength of the end ring decreases.

SUMMARY OF THE INVENTION

A fan wheel of a blower fan includes a first base portion including a first flange, a second base portion including a second flange and a plurality of blades extending between the first base portion and the second base portion. The fan wheel is rotatable about an axis of rotation. A first end ring is attached to an inner perimeter of the first base portion, the first end ring including a third flange that extends outwardly relative to the axis of rotation. A second end ring is attached to an inner perimeter of the second base portion, the second end ring including a fourth flange that extends outwardly relative to the axis of rotation.
Another aspect provides a fan coil unit including a coil and a blower fan. Refrigerant flows through the coil, and the blower fan draws air over the coil to exchange heat with the refrigerant flowing through the coil. The blower fan includes a housing and a fan wheel located in the housing. The fan wheel includes a first base portion including a first flange, a second base portion including a second flange and a plurality of blades extending between the first base portion and the second base portion. The fan wheel is rotatable about an axis of rotation. A first end ring is attached to an inner perimeter of the first base portion, the first end ring including a third flange that extends outwardly relative to the axis of rotation. A second end ring is attached to an inner perimeter of the second base portion, the second end ring including a fourth flange that extends outwardly relative to the axis of rotation.
Another aspect provides a refrigeration system including a compressor for compressing a refrigerant, a condenser for cooling the refrigerant, an expansion device for expanding the refrigerant, and a fan coil unit. The fan coil unit includes an evaporator coil and a blower fan. Refrigerant flows through the evaporator coil, and the blower fan draws air over the evaporator coil to reject heat to the refrigerant flowing through the evaporator coil. The blower fan includes a housing and a fan wheel located in the housing. The fan wheel includes a first base portion including a first flange, a second base portion including a second flange and a plurality of blades extending between the first base portion and the second base portion. The fan wheel is rotatable about an axis of rotation. A first end ring is attached to an inner perimeter of the first base portion, the first end ring including a third flange that extends outwardly relative to the axis of rotation. A second end ring is attached to an inner perimeter of the second base portion, the second end ring including a fourth flange that extends outwardly relative to the axis of rotation.
These and other features of the present invention will be best understood from the following specification and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The various features and advantages of the invention will become apparent to those skilled in the art from the following detailed description of the currently preferred embodiment. The drawings that accompany the detailed description can be briefly described as follows:

FIG. 1A illustrates a refrigeration system operating in a cooling cycle including a fan coil unit;

FIG. 1B illustrates the refrigeration system operating in a heating cycle including the fan coil unit;

FIG. 2 illustrates an example fan coil unit;

FIG. 3 illustrates a perspective view of a blower fan of the fan coil unit including a housing and a fan wheel;

FIG. 4 illustrates a perspective view of the fan wheel of the blower fan;

FIG. 5 illustrates a perspective view of an enlarged portion of the blower fan of FIG. 4 showing a flange of an end ring;

FIG. 6 illustrates a cross-sectional view of the flange of the end ring; and

FIG. 7 illustrates a cross-sectional view of an angled flange of the end ring.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1A illustrates a refrigeration system 20 operating in a cooling mode. Refrigerant flows through the closed circuit refrigeration system 20. The refrigeration system 20 includes a fan coil unit 21 located inside 17 a building and an outdoor unit 23 located outside 15 the building. The inside 17 of the building and the outside 15 of the building can be separated by a wall 19.
Refrigerant exits a compressor 22 in the outdoor unit 23 at a high pressure and a high enthalpy. A reversing valve 25 directs the refrigerant through a first heat exchanger 24, which operates as a condenser. In the first heat exchanger 24, the refrigerant flows through a coil 26 and rejects heat to air that is drawn over the coil 26 by a fan 29. In one example, the fan 29 is a propeller fan. In the first heat exchanger 24, the refrigerant is condensed into a liquid that exits the first heat exchanger 24 at a low enthalpy and a high pressure.
The refrigerant bypasses an outdoor expansion device 26 b (described below) and travels to the fan coil unit 21 through tubing 37. In the fan coil unit 21, the cooled refrigerant then passes through an indoor expansion device 26 a, expanding the refrigerant to a low pressure. After expansion, the refrigerant flows through a second heat exchanger 28, which operates as an evaporator. A blower fan 30 draws air through the second heat exchanger 28 and over a coil 27. The refrigerant flowing through the coil 27 accepts heat from air, exiting the second heat exchanger 28 at a high enthalpy and a low pressure.
The refrigerant then flows back to the outdoor unit 23 through tubing 39. The refrigerant can flow through an accumulator 31, which regulates the amount of refrigerant flowing through the refrigeration system 20. The refrigerant then flows to the compressor 22, completing the cycle.
FIG. 1B illustrates the refrigeration system 20 operating in a heating mode. Refrigerant exits the compressor 22 in the outdoor unit 23 at a high pressure and a high enthalpy. The reversing valve 25 directs the refrigerant to the fan coil unit 21 through the tubing 39.
In the fan coil unit 21, the refrigerant flows through the second heat exchanger 28, which operates as a condenser. A blower fan 30 draws air through the second heat exchanger 28 and over the coil 27. In the second heat exchanger 28, the refrigerant flows through the coil 27 and rejects heat to air and is condensed into a liquid, exiting the second heat exchanger 28 at a low enthalpy and a high pressure. The refrigerant exits the coil 27 and bypasses the indoor expansion device 26 a.
The refrigerant exits the fan coil unit 21 and flows through the tubing 37 towards the outdoor unit 23, where the refrigerant is expanded to a low pressure in the outdoor expansion device 26 b. After expansion, the refrigerant flows through the first heat exchanger 24, which operates as an evaporator. In the first heat exchanger 24, the refrigerant flows through the coil 26 and accepts heat from air that is drawn over the coil 26 by the fan 29, exiting the first heat exchanger 24 at a high enthalpy and a low pressure. The refrigerant can flow through the accumulator 31. The refrigerant then flows to the compressor 22, completing the cycle.
FIG. 2 illustrates the fan coil unit 21. The fan coil unit 21 includes a housing 41 that contains the blower fan 30 that draws the air over the coil 26. A motor 58 rotates the blower fan 30 about an axis of rotation 70. Air enters the blower fan 30 through an inlet orifice 60 and exits the blower fan 30 through an outlet 68.
As shown in FIG. 3, the blower fan 30 includes a fan wheel 32 and a housing 34. In one example, the housing 34 is metal. The fan wheel 32 rotates about the axis of rotation 70.
As shown in FIGS. 6 and 7, the fan wheel 32 includes two base portions 85 and a plurality of blades 40 connected by and extending between the base portions 85. In one example, the base portions 85 are substantially circular. Each of the plurality of blades 40 includes a first end 42 and an opposing second end 44 that are each integrally formed with one of the base portions 85. Each base portion 85 includes a flange 84 that is non-perpendicular to the axis of rotation 70. In one example, the flange 84 is substantially parallel to the axis of rotation 70. As shown in FIGS. 4 and 5, the plurality of blades 40 are equally spaced and define a space 46 between each of the plurality of blades 40. The plurality of blades 40 are substantially parallel to each other and define a wheel inner diameter 64 and a wheel outer diameter 65.
The fan wheel 32 also includes a first end ring 36 and a second end ring 38. The end rings 36 and 38 are substantially the same size and shape. In one example, the end rings 36 and 38 are substantially circular. The end rings 36 and 38 are each attached to one of the base portions 85 (shown in FIGS. 6 and 7). In one example, the end rings 36 and 38 are attached to the base portions 85 by crimping, as further explained below. The end rings 36 and 38 each define an end ring inner diameter 66 and an end ring outer diameter 67.
In one example, the fan wheel 32 is substantially cylindrical in shape. A cross-section of each of the plurality of blades 40 taken substantially perpendicularly to a length 48 of the blades 40 is substantially arc-shaped.
A wheel disc 50 is attached to the plurality of blades 40 at a location 52 along the length 48 of the blades 40 that is substantially equidistant from each of the ends 42 and 44. The wheel disc 50 includes a hub 51 that receives a shaft 54 of the motor 58, and a setup screw 53 mounts the wheel disc 50 to the shaft 54. As the motor 58 rotates the shaft 54, the fan wheel 32 rotates about the axis of rotation 70 to draw air into the fan wheel 32.
The housing 34 includes the inlet orifice 60 and the outlet 68. In one example, the inlet orifice 60 is substantially circular and has an orifice diameter 62. The fan wheel 32 is installed in the housing 34 such that the axis of rotation 70 of the fan wheel 32 is substantially centered within the inlet orifice 60. In one example, the housing 34 includes a planar surface 61, and the inlet orifice 60 is defined in the plane of the planar surface 61.
As the fan wheel 32 rotates about the axis of rotation 70, air is drawn into the inlet orifice 60 of the housing 34 and through the spaces 46 between the blades 40 of the fan wheel 32. The air is directed in an outwardly direction relative to the axis of rotation 70 of the fan wheel 32 and through the outlet 68 of the housing 34. The blower fan 30 draws air over the coil 27, the air exchanging heat with the refrigerant flowing through the coil 27.
As stated above, the second heat exchanger 28 can be an evaporator or a condenser. If the second heat exchanger 28 is an evaporator, the air rejects heat to the refrigerant flowing through the coil 27. If the second heat exchanger 28 is a condenser, the air accepts heat from the refrigerant flowing through the coil 27.
The size and shape of the inlet orifice 60 affects the flow of air into the fan wheel 32, and therefore efficiency. The orifice diameter 62 of the inlet orifice 60 of the housing 34 should be as large as possible. This allows the air to be directly drawn into the fan wheel 32, and the air is not required to make any abrupt turns that can impede the flow of air into the fan wheel 32.
As shown in FIGS. 6 and 7, each flange 84 includes an inner surface 86 facing the axis of rotation 70, an outer surface 88 facing away from the axis of rotation 70 and an end 90. The end rings 36 and 38 are each attached to the flanges 84 at an inner perimeter of the flanges 84, the inner perimeter being defined by the inner surface 86.
The end rings 36 and 38 each include a projection 106 that is crimped under a hooked portion 108 of the flange 84, an inner portion 92 flush with the inner surface 86 of one of the flanges 84, an outer portion 94 flush with the outer surface 88 of one of the flanges 84, and a bend 96 that folds around the end 90 of one of the flanges 84. The inner portion 92 and the outer portion 94 are substantially parallel.
Once crimped around the flanges 84 of the base portions 85, the end rings 36 and 38 also include a flange 98 that extends outwardly and transverse to each of the flanges 84. In one example shown in FIG. 6, the flange 98 extends outwardly from the outer portion 94 and substantially perpendicular to the axis of rotation 70 of the fan wheel 32. An outermost edge 100 of the flange 98 defines the end ring outer diameter 67 of the end rings 36 and 38. In one example, the flange 98 is straight and does not include any bends. Additionally, an outer surface 102 and an inner surface 104 of the flange 98 are not contacted by any other surface.
In another example shown in FIG. 7, the flange 98 is angled with respect to a plane defined by the wheel disc 50. For example, the flange 98 can be angled outwardly (shown in FIG. 7) away from the wheel disc 50 such that an angle A° between the flange 98 and the plurality of blades 40 is obtuse. However, the flange 98 can also be angled inwardly (not shown) towards the wheel disc 50 such that the angle A° between the flange 98 and the plurality of blades 40 is acute.
The flange 98 provides additional strength to the end rings 36 and 38, allowing the end ring inner diameter 66 to be increased. Increasing the end ring inner diameter 66 allows the orifice diameter 62 to be increased, increasing efficiency and reducing re-circulation flow by assisting the flow of air drawn into the fan wheel 32.
In one example, for a 42 size fan coil unit, adding a flange 98 to the end rings 36 and 38 reduces the power of the blower fan 30 by approximately 4% at the same operation point (same airflow and same external static pressure) as a blower fan of the prior art, saving costs. The aerodynamic flow of the blower fan 30 reduces the watts consumption of the blower fan 30, reducing the cost of the outdoor unit 23. The size of the blower fan 30 could also be reduced.
The foregoing description is only exemplary of the principles of the invention. Many modifications and variations of the present invention are possible in light of the above teachings. The preferred embodiments of this invention have been disclosed, however, so that one of ordinary skill in the art would recognize that certain modifications would come within the scope of this invention. It is, therefore, to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described. For that reason the following claims should be studied to determine the true scope and content of this invention.

Claims

1. A fan wheel of a blower fan, the fan wheel comprising:

a first base portion including a first flange;

a second base portion including a second flange;

a plurality of blades extending between the first base portion and the second base portion, wherein the fan wheel is rotatable about an axis of rotation;

a first end ring attached to an inner perimeter of the first base portion, the first end ring including a third flange that extends outwardly relative to the axis of rotation; and

a second end ring attached to an inner perimeter of the second base portion, the second end ring including a fourth flange that extends outwardly relative to the axis of rotation.

2. The fan wheel as recited in claim 1 wherein the plurality of blades define a wheel outer diameter and the third flange and the fourth flange define an end ring outer diameter, and the end ring outer diameter is greater than the wheel outer diameter.

3. The fan wheel as recited in claim 1 wherein the first flange and the second flange are substantially parallel to the axis of rotation.

4. The fan wheel as recited in claim 1 wherein the first end ring and the second end ring are substantially identical.

5. The fan wheel as recited in claim 1 wherein the third flange and the fourth flange are substantially perpendicular to the axis of rotation.

6. The fan wheel as recited in claim 1 wherein the third flange and the fourth flange are transverse to the axis of rotation.

7. The fan wheel as recited in claim 1 further including a wheel disc attached to each of the plurality of blades at a location that is substantially equidistant from a first end and an opposing second end of the plurality of blades, wherein the wheel disc includes a hub that receives a shaft of a motor, and the motor rotates the shaft to rotate the fan wheel about the axis of rotation.

8. The fan wheel as recited in claim 1 wherein the plurality of blades are substantially parallel.

9. The fan wheel as recited in claim 1 wherein the fan wheel is substantially cylindrical.

10. A fan coil unit comprising:

a coil, wherein refrigerant flows through the coil; and

a blower fan that draws air over the coil to exchange heat with the refrigerant flowing through the coil, wherein the blower fan includes a housing and a fan wheel located in the housing,

wherein the fan wheel includes a first base portion including a first flange, a second base portion including a second flange and a plurality of blades extending between the first base portion and the second base portion, wherein the fan wheel is rotatable about an axis of rotation, and

wherein the fan wheel includes a first end ring attached to an inner perimeter of the first base portion, the first end ring including a third flange that extends outwardly relative to the axis of rotation, and a second end ring attached to an inner perimeter of the second base portion, the second end ring including a fourth flange that extends outwardly relative to the axis of rotation.

11. The fan coil unit as recited in claim 10 wherein the plurality of blades define a wheel inner diameter and the third flange and the fourth flange define an end ring inner diameter, the housing includes an inlet orifice having an orifice diameter, and the orifice diameter is substantially equal to the end ring inner diameter and greater than the wheel inner diameter, and the fan wheel draws air over the coil and into the inlet orifice of the housing and discharges the air through an outlet of the housing.

12. The fan coil unit as recited in claim 10 wherein the plurality of blades define a wheel outer diameter and the third flange and the fourth flange define an end ring outer diameter, and the end ring outer diameter is greater than the wheel outer diameter.

13. The fan coil unit as recited in claim 10 wherein the first flange and the second flange are substantially parallel to the axis of rotation.

14. The fan coil unit as recited in claim 10 wherein the third flange and the fourth flange are substantially perpendicular to the axis of rotation.

15. The fan coil unit as recited in claim 10 wherein the third flange and the fourth flange are transverse to the axis of rotation.

16. A refrigeration system comprising:

a compressor for compressing a refrigerant;

a condenser for cooling the refrigerant;

an expansion device for expanding the refrigerant; and

a fan coil unit including an evaporator coil and a blower fan, wherein the refrigerant flows through the evaporator coil and the blower fan draws air over the evaporator coil to reject heat to the refrigerant, wherein the blower fan includes a housing and a fan wheel located in the housing,