Abstract:
A blower housing of novel two-piece construction is comprised of first and second housing parts of stamped or drawn sheet metal that are attached together. The two-piece construction provides the housing with two interior portions separated by an interior wall. The interior wall has an opening that is spaced from the aligned exhaust opening of the heater and the output opening of the housing. This creates a winding exhaust gas flow path through the blower housing. The interior wall is also provided with a recessed cavity that receives a portion of a fan rotated by a motor supported by the blower housing. Positioning of at least a portion of the fan in the cavity reduces the overall height dimension of the blower housing and facilitates the retrofitting of the blower housing between an existing exhaust opening of a heater and an axially aligned flue pipe.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention pertains to a heater blower apparatus that is primarily intended for use as a non-dilution water heater blower. The apparatus is designed to be retrofit to an existing water heater between the axially aligned heater exhaust opening and a flue pipe. 
         [0003]    2. Description of the Related Art 
         [0004]    In the basic construction of a water heater, a fuel such as gas is burned in a combustion chamber of the water heater to heat water passed through the water heater. The water typically travels through a series of coils in the water heater. Combustion of the fuel in the combustion chamber produces hot combustion exhaust gas that passes through the series of coils and heats the water passing through the coils. The combustion exhaust gas then exits the water heater through an exhaust opening of the water heater and then passes through a flue pipe that conducts the gas out of the building containing the water heater. 
         [0005]    Many prior art water heaters are connected to a flue pipe or chimney where only the draft effect of the flue pipe or chimney moves the exhaust gas up through the flue pipe or chimney. Because only the difference in temperature and pressure between the hot exhaust gas inside the water heater and the ambient air outside the water heater would cause the gas to move upwardly through the flue pipe or chimney, prior art water heaters were designed to avoid restricting the flow of the exhaust gas upwardly through the water heater to ensure that the gas would exit the water heater through the flue pipe or chimney. This limited the number of coils that could be positioned inside the water heater so as not to overly restrict the flow of the exhaust gas through the water heater. This in turn reduced the efficiency of the water heater. 
         [0006]    To increase efficiency, water heaters have been designed where the hot gas of combustion is drawn through an increased number of coils of the water heater to provide an increased amount of heat transfer from the heat of the gas to the water passing through the coils. A greater number of coils enables a greater amount of heat transfer. However, this also required that the water heater be constructed with a blower apparatus that would draw the combustion gas through the coils of the water heater and to the flue pipe exhausting the gas. 
         [0007]    The addition of a blower apparatus to a water heater increased the overall cost of the water heater. In addition, because the blower apparatus would draw the exhaust gas quickly through the water heater and into the blower apparatus, the increased temperature of the exhaust gas drawn into the blower apparatus often required that the blower apparatus mix ambient dilution air with the hot exhaust gas to cool the gas. The need to draw dilution air into the blower apparatus to cool the exhaust gas often required that the blower apparatus have a more complicated blower housing design and a more powerful motor for the fan of the apparatus. The more complicated blower housing design often increased the cost of manufacturing the blower apparatus, detracting from the energy savings of the dilution blower apparatus. The energy used by the more powerful motor also would negate some of the energy savings realized by increasing the heat transfer between the combustion gas and the coils of the water heater. 
       SUMMARY OF THE INVENTION 
       [0008]    What is needed to overcome the problems experienced with prior art blower apparatus employed with water heaters is a blower apparatus having a more simplified housing construction that can be manufactured inexpensively. In addition, the blower apparatus should be a non-dilution type to avoid the increased cost of a more complicated blower housing design and a more powerful motor for the apparatus. With the apparatus being non-dilution, the apparatus housing should be able to withstand the increased heat of combustion exhaust gas drawn into the housing. Furthermore, the blower housing construction must enable the apparatus to be retrofit between an existing heater exhaust opening and an existing flue pipe that exhausts the combustion gas of the heater. Still further, to facilitate retrofitting the heater blower apparatus between an existing heater exhaust opening and flue pipe, the vertical height dimensions of the blower housing must be minimized. Although it is necessary that the blower housing have a limited height dimension, it is also desirable that the blower housing restrict the free flow of heat from the water heater up through the exhaust flue pipe when the water heater is in a standby mode and water is not circulating through the water heater. 
         [0009]    The heater blower apparatus of the present invention is designed to be retrofit to a heater, for example a water heater, between the existing heater exhaust opening and a flue pipe. The apparatus has a blower housing of novel construction that facilitates the insertion of the apparatus between an axially aligned heater exhaust opening and a flue pipe. In addition, the novel construction of the blower housing has an interior exhaust gas flow path that changes direction as it extends through the interior of the blower housing, and thereby significantly reduces standby energy losses from the water heater. 
         [0010]    The blower housing in the preferred embodiment is a non-dilution blower housing constructed of only two parts. Also in the preferred embodiment, a first part and a second part of the blower housing are formed of stamped or drawn sheet metal, thereby reducing their cost of manufacture and providing a non-dilution blower housing that can withstand the increased heat of combustion gas drawn into the housing. The first part of the housing is formed with one side positioned in a single plane that facilitates the mounting and sealing of the one side on an exterior surface of a heater such as a water heater. The first part of the housing is also dimensioned to extend over the exhaust opening of the water heater, positioning the exhaust opening in the interior of the first part of the housing. There are no dilution openings or vent openings to the housing first part. This maximizes the ability of the blower housing to generate a negative pressure to draw exhaust gases through the heater and into the blower housing. 
         [0011]    The housing second part is designed to be attached on top of the housing first part, thereby completing the construction of the blower housing. The housing second part can be attached to the housing first part by threaded fasteners, by sealants or adhesives, or by other equivalent means. With the housing second part attached on top of the housing first part, the assembled blower housing encloses an interior having internal structure that creates a winding exhaust gas flow path through the blower housing. The construction of the housing second part includes the output opening of the blower housing. The output opening is generally positioned axially above and at least partially overlaps the heater exhaust opening when the blower housing is assembled to the exterior of the heater over the exhaust opening flue. 
         [0012]    The internal structure of the blower housing includes an interior wall that is formed by the housing first part. The interior wall extends through the blower housing interior and divides the interior into a first portion that communicates with the heater exhaust opening and a second portion that communicates with the blower housing output opening. An additional opening is provided through the interior wall. The additional opening is spaced out of alignment with the heater exhaust opening and the blower housing output opening, thereby creating the winding path of exhaust gas flow through the blower housing interior. 
         [0013]    The interior wall is also formed with a recessed cavity. The opening through the interior wall is positioned in the recessed cavity. The recessed cavity is dimensioned to receive at least a portion of a fan inside the cavity. This enables the blower housing to contain the fan in the interior of the blower housing while also enabling a reduction in the overall vertical height dimension of the blower housing on the exterior surface of the heater. 
         [0014]    The second part of the blower housing supports a motor. The motor is positioned on the housing second part with a shaft of the motor extending into the blower housing to the fan contained in the blower housing interior. Operation of the motor rotates the fan in the blower housing. Rotation of the fan draws exhaust gas through the heater exhaust opening, then through the first portion of the blower housing interior, then through the opening in the blower housing interior wall to the fan, and then pushes the exhaust gas through the second portion of the blower housing interior to the output opening of the blower housing. The gas is then forced through the blower housing output opening to the flue pipe connected to the blower housing. 
         [0015]    The circuitous or winding path of the exhaust gas through the interior of the blower housing reduces standby losses from the heater to which the blower apparatus is attached. In addition, a damper could be added to the interior of the blower housing to further reduce standby losses of the heater. 
         [0016]    Thus, the novel construction of the blower housing of the invention enables the positioning of an interior wall in the blower housing to create the winding path for exhaust gas flow to reduce standby losses, and also enables positioning the fan in the blower housing while limiting the vertical height dimension of the blower housing. 
         [0017]    Furthermore, the novel construction enables the blower housing to be retrofit or assembled to an exterior surface of a heater over the exhaust opening of the heater and between the existing exhaust opening and a flue pipe. 
         [0018]    Still further, the desirable features of the blower housing are attained by providing a housing of only two-piece construction that in the preferred embodiment are stamped or drawn from metal sheet, thereby reducing the overall costs involved in the construction of the blower housing. 
     
    
     
       DESCRIPTION OF THE DRAWINGS 
         [0019]    Further features of the heater blower apparatus of the invention are set forth in the following detailed description of the preferred embodiment of the apparatus and in the drawing figures. 
           [0020]      FIG. 1  is a side elevation view of the heater blower apparatus of the invention assembled between an existing heater exhaust opening on an exterior surface of a heater and a flue pipe. 
           [0021]      FIG. 2  is a top perspective view of the apparatus and heater exterior surface shown in  FIG. 1  with the flue pipe removed. 
           [0022]      FIG. 3  is a top plan view of the blower apparatus and the heater exterior surface. 
           [0023]      FIG. 4  is a view of the apparatus similar to that of  FIG. 1 , but shown as a cross-section in the plane of line  4 - 4  of  FIG. 3 . 
           [0024]      FIG. 5  is a top perspective view of the blower housing first part removed from the blower apparatus and heater. 
           [0025]      FIG. 6  is a bottom perspective view of the blower housing first part. 
           [0026]      FIG. 7  is a top plan view of the blower housing first part. 
           [0027]      FIG. 8  is a cross-section view of the blower housing first part in the plane of line  8 - 8  shown in  FIG. 7 . 
           [0028]      FIG. 9  is a top perspective view of the blower housing second part removed from the blower apparatus and the heater. 
           [0029]      FIG. 10  is a bottom perspective view of the blower housing second part. 
           [0030]      FIG. 11  is a top plan view of the blower housing second part. 
           [0031]      FIG. 12  is a cross-section view of the blower housing second part in the plane of line  12 - 12  shown in  FIG. 11 . 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0032]    The heater blower apparatus  12  of the present invention is primarily designed for use on a conventional water heater and has a simplified, inexpensive two-piece blower housing  14 . Although primarily designed for use on top of a water heater, the concepts of the apparatus  12  may be employed on other similar types of heaters. To enable the blower apparatus to be retrofit to an existing water heater, the apparatus is designed with a unique blower housing  14  that has a reduced vertical height dimension and is capable of being inserted between an existing exhaust opening of the water heater and an axially aligned flue pipe. The blower housing  14  also has a winding exhaust gas flow path through the interior of the housing that allows the exhaust gas to cool as it flows through the housing, thereby enabling the apparatus to be a non-dilution blower apparatus. In addition, the winding exhaust gas flow path through the housing interior reduces standby losses of the water heater. 
         [0033]    In addition to the novel two-piece construction of the blower housing  14 , the heater blower apparatus  12  of the invention also comprises an electric motor  16  and its associated circuitry  18 , and a fan  22  connected to an output shaft  24  of the motor for rotation of the fan with the output shaft. Because the blower apparatus  12  is a non-dilution blower apparatus, the motor  16  employed with the apparatus is a smaller, more energy efficient motor than those typically employed in dilution blower apparatus. Apart from this, the motor  16 , the motor circuitry  18 , and the fan  22  of the heater blower apparatus  12  are for the most part conventional and their details will not be further described herein. 
         [0034]    Furthermore, the water heater  26  and the exhaust gas flue pipe  28  with which the apparatus  12  is designed to be used are of a conventional construction. The water heater is represented by the top flat exterior surface  26  of the water heater shown in  FIGS. 1 ,  2 ,  3  and  4 . The water heater  26  shown has an exhaust pipe  32  that surrounds an exhaust opening  34  of the heater. The exhaust opening  34  has a center axis  36  that is coaxial with a center axis of the flue pipe  28 . Because the water heater and the exhaust gas flue pipe are conventional apart from the center axis  36  of the water heater exhaust opening  34  and the center axis  36  of the flue pipe  28  being coaxial, the details of the constructions of the water heater and flue pipe will not be further described herein. 
         [0035]    The two-piece construction of the blower housing  14  basically consists of a first part  42  and a second part  44 . Both parts in the preferred embodiment of the application are constructed entirely of sheet metal. To reduce the manufacturing costs of the two parts  42 ,  44 , in the preferred embodiment both parts  42 ,  44  are formed of stamped or drawn sheet metal. 
         [0036]    The housing first part  42  is designed to be attached directly to the exterior surface  26  of the water heater with the first part  42  extending around and sealing around the water heater exhaust opening  34 . This defines the blower housing  14  as a non-dilution blower housing. With the housing first part  42  attached to the water heater exterior surface  26 , the center axis  36  of the heater exhausts opening  34  defines mutually perpendicular axial and radial directions relative to the housing first part  42 . 
         [0037]    The housing first part  42  is provided with a bottom flange  46  that projects radially outwardly from the bottom of the housing first part  42  and extends completely around the housing first part  42 . The flange  46  is positioned in a single plane that enables the flange to be securely attached to the flat exterior surface  26  of the water heater. The flange  46  can be attached to the heater exterior surface  26  by threaded fasteners, by spot welds or rivets, by adhesives, or by other equivalent means of attachment. Thus, the flange  46  surrounds and defines an input opening into the interior of the housing first part  42 , which is also a first portion of the interior  48  of the two-piece blower housing  14 . In alternate embodiments, the housing first part  42  could be provided with a bottom wall that extends entirely across the input opening of the first part  42 . Such a bottom wall would include at least one opening that would accommodate the water heater exhaust pipe  32  and the exhaust opening  34  when the housing first part  42  is attached to the water heater exterior surface  26 . 
         [0038]    The housing first part  42  is also formed with a first part side wall  52  that extends axially upwardly from a radially inner edge of the housing first part bottom flange  46 . The housing first part side wall  52  extends completely around the interior  48  of the housing first part  42  and is a continuous extension from the housing first part bottom flange  46  with there being no openings, separations, etc. between the housing first part bottom flange  46  and the housing first part side wall  52 . As shown in the drawing figures, the axial height dimension of the housing first part side wall  52  is sufficient to extend vertically beyond the top edge of the water heater exhaust pipe  32 . 
         [0039]    The housing first part  42  also includes a first part top wall  56  that extends radially inwardly from the top edge of the housing first part side wall  52 . The housing first part top wall  56  is a continuous extension from the housing first part side wall  52  with there being no openings, separations, etc. between the housing first part top wall  56  and housing first part side wall  52 . Thus, the housing first part side wall  52  completely surrounds the housing first part top wall  56 . Much of the housing first part top wall  56  is formed as a flat surface that is parallel with the plane of the housing first part bottom wall flange  46 . A portion of the housing first part top wall  56  is formed as a volute-shaped cavity defined by a spiral cavity side wall  58 . The cavity side wall  58  has a radial dimension that is slightly larger than the diameter dimension of the fan  22  circumference of rotation. As shown in the drawing figures, the cavity side wall  58  extends axially from the housing first part top wall  56  into the housing first part interior  48  toward the housing first part bottom wall flange  46 . The cavity side wall  58  spirals around an axis  62  that is parallel to, but spaced radially from the heater exhaust opening axis  36  when the blower housing  12  is attached to the heater exterior surface  26 . The cavity side wall  58  extends axially into the housing first part interior  48  to a flat cavity bottom wall  64 . A circular first opening  66  passes through the housing first part top wall  56  at the center of the flat cavity bottom wall  64 . The circular first opening  66  has a center axis  62  that is coaxial with the cavity side wall axis  62 . The cavity bottom wall opening  66  is the only opening through the housing first part  42 , except for any fastener openings that may be provided through the housing first part bottom wall flange  46  for attaching the housing first part  42  to the heater exterior surface  26 . The cavity bottom wall also has a sloped portion  68  that slopes downwardly from the housing first part top wall  56  to the flat cavity bottom wall  64  as shown in  FIGS. 5 ,  7 , and  8 . 
         [0040]    The housing second part  44  is also formed with a second part bottom wall flange  72  that projects radially outwardly from the housing second part  44  and is positioned in a single horizontal plane. The housing second part bottom wall flange  72  has a configuration that follows, or is similar to the configuration of the housing first part side wall  52  and is dimensioned slightly smaller than the housing first part side wall  52 . This enables the housing second part bottom wall flange  72  to be attached to the housing first part top wall  56  with the second part flange  72  positioned radially just inside of the housing first part side wall  52 . The housing second part bottom flange  72  can be attached to the housing first part top wall  52  by threaded fasteners, by spot welds or rivets, by adhesives, or by other equivalent means of attachment. 
         [0041]    The housing second part  44  also has a second part side wall  74  that extends axially upwardly from an inner edge of the housing second part bottom flange  72 . The housing second part side wall  52  is continuous with the housing second part bottom flange  72  and extends completely around the housing second part bottom flange  72  with there being no openings, interruptions, etc. between the housing second part bottom flange  72  and the housing second part side wall  74 . The housing second part side wall  74  extends completely around the interior of the housing second part  44 , and surrounds a second portion of the interior  76  of the two-piece blower housing  14 . As seen in the drawing figures, the axial dimension or vertical height of the housing second part side wall  74  is approximately the same as that of the housing first part side wall  52 . In an alternate embodiment of the blower housing, the housing second part side wall  74  is attached directly to the housing first part  42  with the housing second part  44  not having the second part flange  72 . 
         [0042]    The housing second part  44  is also formed with a second part top wall  78  that extends radially inwardly from the top edge of the second part side wall  74 . The second part top wall  78  is a continuous extension of the second part side wall  74  and the second part side wall  74  completely surrounds the second part top wall  78 . Much of the second part top wall  78  is a flat planar surface that is parallel with the plane of the second part bottom flange  72 , the plane of the housing first part top wall  56 , and the plane of the housing first part bottom flange  46 . A portion of the housing second part top wall  78  is formed as a cylindrical output rim  82  that extends axially upwardly from the second part top wall  78 . The output rim  82  surrounds a second opening or an output opening  84  of the blower housing  14 . The output opening  84  is circular and has a center axis  36  that is at least generally parallel to, and preferably is coaxial with the heater exhaust opening axis  36  when the apparatus  12  is attached to the heater exterior surface  26 . In many applications, the output opening  84  is positioned generally axially above and at least partially overlaps the heater exhaust opening  34 . In addition, the second part output opening axis  36  is spaced radially from and is parallel with the center axis  62  of the housing first part first opening  66 . The housing second part output rim  82  has a circumferential dimension or a diameter dimension that is complementary to the respective circumferential dimension or diameter dimension of a flue pipe  28  or of an adapter connected to the flue pipe. 
         [0043]    In addition to the output opening  84  through the housing second part top wall  78 , the second part top wall  78  has a shaft opening  86  therethrough. The shaft opening  86  is positioned on the second part top wall  78  where a center axis of the shaft opening  86  is coaxial with the axis  62  of the housing first part first opening  66 . The housing second part output opening  84  and the shaft opening  86  are typically the only openings through the housing second part  44 . When the blower housing  14  includes an optional damper  88  in the housing second part  44  to further reduce stand-by losses, an additional pair of holes  92  could be provided in the second part side wall  74  to mount the damper  88  for pivoting movement. These additional holes  92  could be sealed to avoid reducing the draw of the blower housing  14 . 
         [0044]    The motor  16  is attached to the top wall  78  of the housing second part  44  with the motor shaft  24  extending through the shaft opening  86  and into the housing interior. The fan  22  is connected to the motor shaft  24  and is positioned in the blower housing interior between the housing first part top wall  56  and the housing second part top wall  78 . The fan  22  has an axis of rotation that is coaxial with the axis  62  of the cavity bottom wall opening  66 . As shown in the drawing figures, the axial dimension of the fan  22  extends into the cavity defined by the cavity side wall  58  in the housing first part top wall  56 . Thus, at least a portion of the axial length of the fan  22  is received inside the cavity defined by the cavity side wall  58  of the housing first part top wall  56 . This enables the fan  22  to be completely contained inside the blower housing  14  while also reducing the vertical height dimension of the blower housing  14 . This also enables the blower housing  14  to be attached to the heater exterior surface  46  between the existing water heater flue  28  and exhaust opening  32  and an existing flue pipe  34 . 
         [0045]    The construction of the two-piece blower housing  14  described above also enables the apparatus  12  to be assembled or retrofit to an existing water heater  26  between the exhaust pipe  32  and exhaust opening  34  of the water heater  26  and an axially aligned existing flue pipe  28 . 
         [0046]    Still further, the construction of the two-piece blower housing  14  described above creates a winding exhaust gas flow path through the blower housing. On operation of the motor  16  and rotation of the fan  22  in the blower housing, exhaust gas is drawn axially through the water heater exhaust pipe  32  and the exhaust opening  34 . The exhaust gas then travels radially from the water heater exhaust opening  34  toward the housing first part cavity side wall  58 . The exhaust gas is then directed axially along the exterior of the housing first part cavity side wall  58 . The exhaust gas then travels radially across the housing first part cavity bottom wall  64  toward the first opening  66  at the center of the cavity bottom wall  64 . The exhaust gas then flows axially through the cavity bottom wall opening  66  toward the center of the rotating fan  22 . The exhaust gas is then pushed radially by the rotating fan  22  through the fan circumference of rotation across the sloped portion  68  of the cavity bottom wall and toward the second housing opening  84 , i.e. the output opening in the housing second part  44 . The exhaust gas is then directed axially through the output opening  84  and into the flue pipe  28 . The winding flow path of the exhaust gas through the two-piece blower housing  14  allows the gas to cool as it passes through the housing. In addition, the winding exhaust gas flow path through the blower housing  14  reduces stand-by losses of the water heater  26 . To further reduce stand-by losses, the blower housing second part  44  could be modified with the damper  88  in the interior of the housing second part  44 . The winding flow path of the exhaust gas through the blower housing is achieved inexpensively by the novel and non-obvious two-piece construction of the blower housing. 
         [0047]    The heater blower apparatus  12  of the invention described above, when equipped with a properly designed water heater can achieve an energy factor (EF) of 0.67, which is the new Energy Star mandate going into effect in the United States on Sep. 1, 2010. The EF of 0.67 can be accomplished while meeting category 1 vent pipe applications (non-condensing and non-pressurized) so that the end user of the apparatus  12  can use an existing vent pipe. 
         [0048]    The heater blower apparatus  12  of the invention described above can replace current atmospheric draft hood water heaters, which cannot meet the EF of 0.67 level. 
         [0049]    The embodiments of the non-dilution blower apparatus were chosen and described in order to best explain the principles of the invention and its practical application to thereby enable others skilled in the art to best utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated. 
         [0050]    As various modifications could be made in the constructions herein described and illustrated without departing from the scope of the invention, it is intended that all matter contained in the foregoing description or shown in the accompanying drawings shall be interpreted as illustrative rather than limiting. For example, the two pieces of the blower housing could be constructed of materials other than stamped or drawn sheet metal, and the blower housing could be employed on a heater other than a water heater. Thus, the breadth and scope of the present invention should not be limited by any of the above-described exemplary embodiments, but should be defined only in accordance with the following claims appended hereto and their equivalents.