Abstract:
A blower housing for a furnace blower assembly of the type including a blower motor coupled to an impeller for use in expelling exhaust gases from a furnace. The blower housing generally includes an inlet, an impeller cavity, and an extension portion extending from the impeller cavity, the extension portion terminating in a circular outlet to which a round flue pipe may be attached. The blower housing is formed by three housing members joined to one another, wherein the housing members may be formed from metal using conventional stamping, drawing, and forming processes, for example. To form a variety of different types of blower housings having different outlet offset distances, only the dimensions of cooperating portions of two of the housing members need be varied, with one of the housing members used in common among the different types of blower housings. In this manner, a number of different types of blower housings may be made for furnaces of different designs while reducing tooling, manufacturing, and inventory costs.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     The present invention relates to blower housings for furnace blower assemblies, the blower housings including an outlet for the attachment of a flue pipe.  
         [0003]     2. Description of the Related Art  
         [0004]     Blower assemblies are used in modern furnaces to increase the fuel efficiency of the furnace burner by inducing a draft through the furnace to draw heated air and products of combustion through a heat exchanger within the furnace and exhaust same through an exhaust pipe. Typically, the blower assembly includes a blower housing mounted to the furnace, the blower housing defining an impeller cavity therein. The blower housing also includes a mounting surface for mounting a motor to the blower assembly. The motor includes an output shaft to which an impeller is affixed, the impeller disposed within the impeller cavity. In operation, the motor rotatably drives the impeller to draw heated air and exhaust gases from the furnace into the blower housing and to exhaust the heated air and exhaust gases through the outlet of the blower housing into a flue pipe to direct the gases away from the furnace.  
         [0005]     Although the addition of a blower assembly has been shown to substantially increase the efficiency of modern furnaces, the blower assembly adds to the overall cost of the furnace and therefore it is desirable to manufacture the blower assembly as economically as possible.  
         [0006]     Some known blower housings include four or more individual components which are made of stamped metal, cast metal, or plastic materials. Generally, the more components which are used to form the blower housing, the easier it is to manufacture each of the components, such as by using conventional metal stamping and drawing processes. However, blower housings which include a large number of components have the disadvantage of requiring an increased parts inventory, and also may be somewhat difficult and labor-intensive to assemble.  
         [0007]     One known blower housing is formed of two components of stamped/drawn metal which are secured to one another by crimping the edge portions of the pieces to one another. Although this type of construction results in a blower housing which is easy to assemble, the shapes of the two blower housing components requires complicated drawing operations to form the components, making the components somewhat difficult to manufacture and leading to increased tooling costs.  
         [0008]     Also, different furnace manufacturers typically have different design requirements for the blower housings, and furthermore, each furnace manufacturer may have different design requirements for different furnaces throughout its product line. For example, the degree of offset, or spacing, of the blower housing outlet from the surface at which the blower housing is mounted to the furnace may vary. Thus, a blower housing which is designed for a particular furnace might not meet the specifications of other furnaces. This requires a manufacturer of blower housings to produce different blower housings of varying specifications in order to suit the needs of each furnace manufacturer.  
         [0009]     What is needed is a blower housing for furnace blower assemblies which is an improvement over the foregoing.  
       SUMMARY OF THE INVENTION  
       [0010]     The present invention provides a blower housing for a furnace blower assembly of the type including a blower motor coupled to an impeller for use in expelling exhaust gases from a furnace. The blower housing generally includes an inlet, an impeller cavity, and an extension portion extending from the impeller cavity, the extension portion terminating in a circular outlet to which a round flue pipe may be attached. The blower housing is formed by three housing members joined to one another, wherein the housing members may be formed from metal using conventional stamping, drawing, and forming processes, for example. To form a variety of different types of blower housings having different outlet offset distances, only the dimensions of cooperating portions of two of the housing members need be varied, with one of the housing members used in common among the different types of blower housings. In this manner, a number of different types of blower housings may be made for furnaces of different designs while reducing tooling, manufacturing, and inventory costs.  
         [0011]     A first housing member includes a top wall to which a motor may be mounted, and an arcuate wall depending from the top wall. A second housing member includes a planar wall for mounting the blower housing to a furnace, and a first extension wall extending from the planar wall which terminates in a first curved outlet wall. The first and second housing members define the impeller cavity therebetween. A third housing member is attached to the first and second housing members, and includes a second extension wall which cooperates with the first extension wall to define the extension portion of the blower housing, and a second curved outlet wall which cooperates with the first curved outlet wall to define the circular outlet of the blower housing.  
         [0012]     Advantageously, the dimensions of the extension walls of the second and third housing members may be modified by a simple retooling of a portion of each of the second and third housing members. Varying the dimensions of the extension walls of the second and third housing members allows for the production of blower housings having a varying degree of offset distance between the planar wall of the second housing member which is attached to the furnace and the edge of the blower housing outlet. The shape of the first housing member need not be varied; rather, the first housing member is a component which is used in common between any number of different types of blower housings. In this manner, different blower housings may be produced in an economically efficient manner.  
         [0013]     In one form thereof, the present invention provides a blower housing for a blower assembly of the type used for expelling gases from a furnace, the blower housing including a cavity including an inlet, and an extension portion extending from the cavity and terminating in an outlet, the blower housing formed from at least three separate housing members, including a first housing member; a second housing member attached to the first housing member and cooperating with the first housing member to define the cavity, the second housing member including the inlet and a first extension wall; and a third housing member attached to at least one of the first and second housing members, the third housing member including a second extension wall, the first and second extension walls cooperating to define the extension portion.  
         [0014]     In another form thereof, the present invention provides a blower assembly for attachment to a furnace, including a blower housing including an impeller cavity having an inlet, and an extension portion extending from the impeller cavity and terminating in an outlet, the blower housing further including a first housing member; a second housing member attached to the first housing member and cooperating with the first housing member to define the impeller cavity, the second housing member further including the inlet and a first extension wall having a curved end portion; and a third housing member attached to at least one of the first and second housing members, the third housing member including a second extension wall having a curved end portion, the first and second extension walls cooperating to define the extension portion and the curved end portions of the second and third housing members cooperating to define the outlet; a motor attached to the blower housing, the motor including an output shaft extending into the impeller cavity; and an impeller mounted to the motor output shaft and disposed within the impeller cavity, whereby upon rotation of the impeller by the motor, air is drawn into the inlet and is forced through the extension portion and out of the blower housing outlet.  
         [0015]     In a further form thereof, the present invention provides a method of assembling blower housings of the type used with a blower motor and impeller for expelling gases from a furnace, the method including the steps of providing a first blower housing member which is common to at least two different types of blower housings; providing at least two second blower housing members of different type; selecting one of the second blower housing members; providing at least two third blower housing members of different type; selecting one of the third blower housing members; attaching the first blower housing member, the selected second blower housing member, and the selected third blower housing member to one another to form a blower housing of a first type. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0016]     The above-mentioned and other features and advantages of this invention, and the manner of attaining them, will become more apparent and the invention itself will be better understood by reference to the following description of embodiments of the invention taken in conjunction with the accompanying drawings, wherein:  
         [0017]      FIG. 1  is a perspective view of a first blower assembly, including a first type of blower housing according to the present invention;  
         [0018]      FIG. 2  is another perspective view of the blower assembly;  
         [0019]      FIG. 3  is a sectional view through the blower assembly;  
         [0020]      FIG. 4  is a front view of the blower assembly;  
         [0021]      FIG. 5  is an exploded view of the blower assembly;  
         [0022]      FIG. 6  is a perspective view of a second blower assembly, including a second type of blower housing according to the present invention;  
         [0023]      FIG. 7  is another perspective view of the blower assembly;  
         [0024]      FIG. 8  is a sectional view through the blower assembly;  
         [0025]      FIG. 9  is a front view of the blower assembly; and  
         [0026]      FIG. 10  is a schematic assembly view illustrating how different types of blower housings may be made according to the present invention, each type of blower housing having a common housing member.  
     
    
       [0027]     Corresponding reference characters indicate corresponding parts throughout the several views. The exemplifications set out herein illustrate preferred embodiments of the invention, and such exemplifications are not to be construed as limiting the scope of the invention in any manner.  
       DETAILED DESCRIPTION  
       [0028]     Referring to  FIGS. 1-5 , blower assembly  20  is shown, which includes a blower housing  22  in accordance with a first embodiment of the present invention. Except as described below, blower assembly  20  includes many features which are similar to the blower assembly disclosed in U.S. Pat. No. 6,468,034, assigned to the assignee of the present invention, the disclosure of which is expressly incorporated herein by reference. Blower assembly  20  generally includes blower housing  22 , motor  24  mounted to blower housing  22 , and impeller  26  disposed within blower housing  22 . Impeller  26  is rotatably driven by motor  24  to draw air from within a furnace (not shown) to which blower assembly  20  is attached through inlet  28  of blower housing  22  and out through outlet  30  of blower housing  22 .  
         [0029]     Blower housing  22  generally includes inlet  28 , impeller cavity  32  in which impeller  26  is disposed, extension or transition portion  34  extending from impeller cavity  32 , and outlet  30  at the end of extension portion  34  for attachment of a flue pipe (not shown) to blower housing  22 . Blower housing  22  is formed from three housing members, including first housing member  40 , second housing member  42 , and third housing member  44 . Each of the first, second and third housing members  40 ,  42 , and  44  is preferably formed from metal by conventional stamping, drawing, and forming operations, but may optionally be formed from cast metals or plastic materials, for example.  
         [0030]     First housing member  40  includes body portion  46  defined by top wall  48  and circular wall  50 . Attachment flange  52  extends outwardly from a substantial portion of the periphery of circular wall  50 , and includes a plurality of apertures  54  therein. First housing member  40  additionally includes three walls  56   a,    56   b,  and  56   c  ( FIG. 5 ) which cooperate with second housing member  42  to define impeller cavity outlet  58 , as described below.  
         [0031]     Second housing member  42  generally includes planar bottom wall  60 , which serves as a mounting surface for mounting blower assembly  20  to a furnace, as described further below. Wall  60  includes blower housing inlet  28  therein, which is shown herein as a circular inlet. Optionally, the shape of inlet  28  may vary. Wall  60  also includes lip  62  extending around a substantial portion of the periphery thereof. A plurality of apertures  64  are defined in wall  60  around its periphery. Extension wall  66  extends from wall  60  and terminates in a curved, half-cylindrical outlet wall  68 , and further includes mounting flanges  70  on its opposite sides.  
         [0032]     Third housing member  44  includes a series of three walls  72   a,    72   b,  and  72   c  ( FIG. 5 ) for attachment to walls  56   a,    56   b,  and  56   c  of first housing member  40 , as described below. Third housing member  44  additionally includes extension wall  76  terminating in a curved half-cylindrical outlet wall  78 . A pair of mounting flanges  80  extend from the opposite sides of extension wall  76 .  
         [0033]     Generally, first, second, and third housing members  40 ,  42 , and  44  may be attached to one another by any suitable method, such as by crimping, gluing, stapling, welding, riveting, screwing, bolting, snap fit, or by any combination of the foregoing. Preferably, however, first housing member  40  is attached to second housing member  42  by placing the attachment flange  52  of first housing member  40  into abutment with wall  60  of second housing member  42  within the periphery of lip  62 , such that apertures  54  in attachment flange  52  of first housing member  40  are aligned with apertures  64  in wall  60  of second housing member  42 . Thereafter, lip  62  of second housing member  42  is crimped over the edge of attachment flange  52  of first housing member  40 . The foregoing crimped attachment between first and second housing members  40  and  42  provides a secure connection therebetween which resists rattling during operation of blower assembly  20 .  
         [0034]     Third housing member  44  is attached to first and second housing members  40  and  42  by positioning walls  72   a,    72   b,  and  72   c  of third housing member  44  over walls  56   a,    56   b,  and  56   c  of first housing member  40  and attaching same together by welding or by suitable fasteners, for example. Concurrently, mounting flanges  80  of third housing member  44  engage the opposite sides of extension wall  66  of second housing member  42 , and mounting flanges  70  of second housing member  42  are thereafter crimped over the edges of mounting flanges  80  of third housing member  44  to securely attach third housing member  44  to second housing member  42 .  
         [0035]     Extension walls  66  and  76  of second and third housing members  42  and  44 , respectively, cooperate to define extension or transition portion  34  of blower housing  22 . Additionally, outlet walls  68  and  78  of second and third housing members  42  and  44 , respectively, cooperate to define outlet  30  of blower housing  22 . Outlet  30  is circular in shape, with a cylindrical profile for attachment of a round exhaust flue (not shown) to outlet  30  using suitable clamps, screws, or other fasteners (not shown), for example. Although outlet walls  68  and  78  each have a half cylindrical profile, the shapes of outlet walls  68  and  78  may be modified whereby one of outlet wall  68  or  78  defines a greater portion of the cylindrical profile of outlet  30  than the other of outlet walls  68  or  78 .  
         [0036]     As shown in  FIGS. 4 and 5 , it may be seen that walls  56   a,    56   b,  and  56   c  of first housing member  40  cooperate with wall  60  of second housing member  42  to define impeller cavity outlet  58 , which has a rectangular profile. In this manner, extension or transition portion  34  of blower housing  22  defines a transition between the rectangular impeller cavity outlet  58  and the circular blower housing outlet  30 .  
         [0037]     Referring to  FIGS. 1 and 3 , motor  24  includes stator  82  and rotor  84  to which output shaft  86  is attached. Impeller  26  is secured to the end of output shaft  86 , and is disposed within impeller cavity  38  in alignment with inlet  28  of second housing member  42  of blower housing  22 , as shown in  FIGS. 2 and 5 . Motor  24  additionally includes fan  88  attached to output shaft  86  intermediate rotor  84  and impeller  26 . Fan  88  is disposed within fan housing  90  and, during operation of motor  24 , fan  88  draws cooling air from between fan housing  90  and top wall  48  of blower housing  22  and blows the cooling air outwardly of fan housing  90  through a plurality of vents  92  ( FIG. 1 ) and over motor  24  to cool motor  24 . Motor  24  includes a plurality of feet  94  for attachment to top wall  48  of blower housing  22  using fasteners  96 , shown herein as nuts and bolts.  
         [0038]     Blower assembly  20  may be mounted to a furnace using suitable fasteners (not shown) which are inserted through the aligned apertures  54  and  64  in first and second housing members  40  and  42 , respectively, of blower housing  22 , and into engagement with suitable mounting structure of the furnace. In operation, motor  24  rotatably drives impeller  26  with impeller cavity  38  to draw air from the furnace into impeller cavity  38 . Thereafter, the air is forced by impeller  26  through impeller cavity outlet  58  and extension portion  34  to exit blower housing  22  through blower housing outlet  30  into a flue pipe.  
         [0039]     Referring to  FIGS. 3 and 4 , it may be seen that extension walls  66  and  76  of second and third housing members  42  and  44 , respectively, are dimensioned to provide a first offset distance D 1  between wall  60  of second housing member  42  and the corresponding surface of the furnace to which blower housing  22  is mounted and the edge of blower housing outlet  30 . The foregoing offset distance D 1  provides a clearance space between the furnace and blower housing outlet  30  to facilitate attachment of a flue pipe to blower housing outlet  30 . Notably, the offset distance D 1  may vary according to the specifications of different furnaces.  
         [0040]     In  FIGS. 6-9 , a second blower assembly  120 , including a second blower housing  122  according to the present invention, is shown. Blower assembly  120  is substantially identical to blower assembly  20  of  FIGS. 1-5 , and identical reference numerals have been used to designate identical features therebetween. However, blower housing  122  of blower assembly  120  includes second housing member  142  having an extension wall  166  which is shorter or smaller than extension wall  66  of second blower housing member  42  of blower housing  22 . Similarly, Blower housing  122  of blower assembly  120  includes third housing member  144  having an extension wall  176  which is shorter or smaller than extension wall  76  of third blower housing member  44  of blower housing  22 . Otherwise, blower housings  22  and  122  are substantially identical.  
         [0041]     Referring to  FIGS. 8 and 9 , it may be seen that a second offset distance D 2  between wall  60  of second housing member  142  and the corresponding surface of the furnace to which blower housing  122  is mounted and the edge of blower housing outlet  30  is less than offset distance D 1  of the blower housing  22  of  FIGS. 1-5 .  
         [0042]     Advantageously however, first housing portion  40  is a common component which is used in both first and second blower housings  22  and  122 . Thus, in order to vary the offset distance for different blower housings in order to suit the needs of a particular furnace design, only the dimensions of the extension walls of the second and third housing members need be changed. Advantageously, because only the extension walls of the second and third housing members need vary between different blower housings while first housing member  40  remains the same, the overall tooling and production costs of the blower housings  22 ,  122  made according to the present invention are greatly reduced.  
         [0043]     For example,  FIG. 10  shows a schematic assembly process by which different types of blower housings may be manufactured according to the present invention. Referring to the right side of  FIG. 10 , to form a first type of blower housing  22 , such as that shown in  FIGS. 1-5 , first housing member  40  is used in combination with second and third housing members  42  and  44 . Referring to the left side of  FIG. 10 , to form a second type of blower housing  122 , such as that shown in  FIGS. 6-9 , first housing member  40  is used in combination with second and third housing members  142  and  144 . Thus, the present invention provides a blower housing including three separate housing members joined to one another, in which the dimensions of a portion of two of the housing members may be varied, with one of the housing members used in common, to provide a number of different types of blower housings.  
         [0044]     While this invention has been described as having a preferred design, the present invention can be further modified within the spirit and scope of this disclosure. This application is therefore intended to cover any variations, uses, or adaptations of the invention using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains and which fall within the limits of the appended claims.