Abstract:
A motor/damper assembly installable on the top end of a fuel-fired water heater includes a support plate structure upon which a flue collar with a pivotally supported flue damper, a drive motor, and a drive shaft interconnecting the motor damper are mounted. The assembly is installed by placing the collar over the upper end of the water heater flue, securing the support plate structure to the top end of the water heater, and positioning a top cover housing on the support plate structure. Using the assembly provides improved support rigidity and alignment for the motor and shaft relative to the damper, improved repeatable precise manufacturing placement of the motor and shaft, improved construction aesthetics, with the cover also protecting the shaft from shipping and handling damages.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    The present application claims the benefit of the filing date of provisional U.S. patent application No. 61/379,026 filed Sep. 1, 2010. The entire disclosure of the provisional application is hereby incorporated herein by this reference. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    In representatively illustrated embodiments thereof, this invention provides specially designed motor/damper apparatus for a fuel-fired liquid heating apparatus, such as a fuel-fired water heater, and a liquid heating apparatus operatively incorporating the motor/damper apparatus. 
         [0003]    The primary purpose of the present invention is to improve the performance, construction and appearance of a motorized damper assembly used in conjunction with a fuel-fired water heater or other type of fuel-fired liquid heating apparatus such as, for example, a fuel-fired boiler. Traditional motorized flue damper assemblies, particularly for commercial fuel-fired water heaters, are constructed as two separate units comprising a drive system and an associated damper plate joined together by a steel channel such that the damper plate portion of the assembly is cantilevered from the drive system. 
         [0004]    This conventional motor/damper assembly tends to be bulky and not particularly well suited, either from a structural or aesthetic standpoint, for residential water heaters. Some of the structural problems present in this conventional motor/damper assembly design include skewing of the damper plate that creates misalignment of and leakage around the damper plate, bending of the motor shaft or rod in shipping and handling, and providing the motor/damper assembly with a less than aesthetically pleasing appearance when installed on a residential water heater. 
         [0005]    A need thus exists for an improved motor/damper assembly which eliminates or at least substantially alleviates these problems, limitations and disadvantages commonly associated with motor/damper assemblies of the conventional type generally described above. It is to this need that the present invention is primarily directed. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0006]      FIG. 1  is a perspective, partially cut away view of a top end portion of a representative fuel-fired water heater on a top end surface of which a motor/damper assembly embodying principles of the present invention is mounted; 
           [0007]      FIG. 2  is a view similar to that in  FIG. 1 , but with the motor/damper assembly removed from the water heater and shown in exploded perspective form; 
           [0008]      FIG. 3  is an enlarged scale exploded perspective view of the motor/damper assembly; 
           [0009]      FIG. 4  is an enlarged scale cross-sectional view through the motor/damper assembly taken generally along line  4 - 4  of  FIG. 1 ; and 
           [0010]      FIG. 5  is a partially cut away side elevational view of the motor/damper assembly, and an upper end portion of the water heater, taken generally along line  5 - 5  of  FIG. 1 . 
       
    
    
     DETAILED DESCRIPTION 
       [0011]    As illustrated in the accompanying  FIGS. 1-5 , this invention provides a specially designed motor/damper assembly  10  which embodies principles of the present invention and is mountable on the top end surface  12  of the insulated hot water storage tank portion  14  of a fuel-fired water heater  16 . Alternatively, the motor/damper assembly  10  could be utilized in conjunction with other types of fuel-fired liquid heating apparatus such as, for example, fuel-fired boilers. Representatively, the fuel-fired water heater  16  is a residential water heater, but could also be a commercial water heater. 
         [0012]    Water storage tank portion  14  (see  FIGS. 1 and 5 ) includes a vertically oriented cylindrical water storage tank  18  surrounded by a suitable insulation material  20  which, in turn, is surrounded by a metal jacket  22 . Extending upwardly from the top end surface  12  of the storage tank portion  14  is a tubular exhaust flue  24  (see  FIGS. 2 and 4 ) having an open upper end  26 . During firing of the water heater  16 , combustion exhaust products (not shown) are upwardly exhausted through the flue  24 . Also projecting upwardly from the top end surface  12  of the storage tank portion  14  are a cold water inlet pipe  28  and a hot water outlet pipe  30  (see  FIGS. 1 ,  2  and  5 )  32  operatively coupled to the tank  18 . 
         [0013]    The motor/damper assembly  10 , as later discussed herein, provides several advantages over conventional motor/damper assemblies, and includes a metal support plate structure  32  (see  FIGS. 2-4 ) having a rectangular base plate portion  34 , an end plate  36  portion projecting upwardly from an end edge of the base plate portion  34 , and a pair of side plate portions  38 , 40  projecting upwardly from opposite side edges of the base plate portion  34 . Mounted on the outer side of the end plate  36 , in an elevated relationship with the base plate  34 , is an electric motor  42 . The inner end of a horizontally oriented drive shaft  44  is drivably coupled to the motor  42 . As schematically depicted in  FIG. 2 , the motor  42  may be incorporated in a damper control module having suitable control electronics therein which are operatively associated with the motor  42 . 
         [0014]    At the right end of the base plate  34  is an upstanding tubular collar  46  having an open lower end portion  48  complementarily received and welded within a corresponding circular opening  50  extending upwardly through the base plate  34 . Collar  46  may have a reduced diameter upper end portion  52  as shown or, alternatively, the upper end portion may be of substantially the same diameter as the rest of the collar  46 . An outer end portion of the drive shaft  44  extends through an upper end slot  54  in the upper collar end portion  52  and is drivingly coupled to a disc-shaped damper plate  56  which is received in the open upper end portion  52  of the collar  46  and rotatable by the motor  42  between a fully open vertical position (see  FIGS. 2-4 ) and a fully closed horizontal position (not shown). 
         [0015]    The motor/damper assembly  10  further includes a hollow cover structure or housing  58  (see  FIGS. 1-5 ) having an elongated, generally rectangular shape, an open bottom side  60 , a top side wall  62 , a left end wall  64 , a right end wall  66 , a left side wall  68 , a right side wall  70 , and a circular opening  72  formed in the top side wall  62  and configured to complementarily receive the open end portion  52  of the tubular collar  46  as later described herein. As best illustrated in  FIGS. 3 and 4 , a left end portion of the housing  58  is vertically enlarged relative to the balance of the housing  58 . 
         [0016]    To assemble the motor/damper assembly  10  and operatively secure it to the top end surface  12  of the storage tank portion  16  of the water heater  16 , as shown in  FIG. 1 , the base plate  34  is first placed on the top tank end surface  12  in a manner such that the upper end of the flue  24  is complementarily received in the open lower end portion  48  of the tubular collar  46  as best illustrated in  FIG. 4 . The base plate  34  is then secured to the top tank end surface  12  using screws  73  (see  FIGS. 2-4 ) extended downwardly through the base plate  34  and threaded into corresponding openings in the top tank end. 
         [0017]    Next, an end portion of an electrical power wiring harness  74  is inserted through a an opening (not shown) in the housing  58  side wall  70  and secured to the housing  58  via a suitable strain relief fitting  76 . Via a connector  78 , the inserted end of the power wiring harness  74  is coupled to a power wiring harness  80  coupled to the motor  42 . Additionally, an electrical control wiring harness  82  coupled to the motor  42  is secured, via a connector  84  to an electrical control wiring harness  86  that extends through an opening  88  and associated strain relief fitting  90  in the top end surface  12  and downwardly through the tank insulation  20  to the fuel valve controller of the water heater (not shown). 
         [0018]    During operation of the water heater  16 , in a generally conventional manner known to those of skill in this particular art, electrical power is transmitted to the motor  42  and the fuel valve controller through the interconnected wiring harnesses  74 ,  80 ,  82  and  86 , and control signals between the valve controller and the motor  42  are transmitted via the wiring harnesses  82  and  86 . Such signals include calls for the damper  56  to open and close, and signals confirming the proper positioning of the damper  56 . 
         [0019]    After the wiring connections are made to the motor  42  as described above, the housing  58  is placed downwardly over the motor  42  and the support structure  32  in a manner such that the open upper end portion  52  of the tubular collar  46  is complementarily received in and projects upwardly beyond the opening  72  in the top side  44  of the housing  58 , and the open bottom side  60  of the housing  58  contacts the top end surface  12  as best shown in  FIG. 4 . The housing  58  is then anchored to the support plate structure  32  by means of screws  92  (see  FIG. 3 ) extended through the opposite side walls  68 , 70  of the housing  58  and threaded into openings  94  in the side plates  38 , 40  of the support plate structure  32 . 
         [0020]    Finally, a conventional draft hood  96  is secured to the top side  62  of the housing  58 , over the upwardly projecting open upper end portion  52  of the tubular collar  46  (see  FIG. 4 ), by extending screws  98  downwardly through bottom ends  100  of depending support leg portions  102  of the draft hood  96  into corresponding holes  104  in the top housing side wall  62 . Draft hood  96  has, it its upper end, a circular flange  106  to which a suitable flue pipe extension (not shown) may be secured when the completed water heater  16  is installed at a job site. If desired, the draft hood  96  may be secured to the housing  58  before the housing  58  is installed on the water heater. 
         [0021]    With reference now to  FIG. 4 , it can be seen that the vertically enlarged left end portion of the installed housing  58  defines therein a chamber  108  which protectively encloses the electric motor  42 . Other accessories, controls, etc. for the motor/damper assembly  10  (not shown) could also be disposed in this chamber if desired. It should also be noted that the top side wall  62  of the housing  58  protectively overlies and shields (from both view and damage) substantially the entire length of the drive shaft  44 . 
         [0022]    As previously mentioned herein, the motor/damper assembly  10  provides several advantages over conventional motor/damper assemblies previously utilized in conjunction with fuel-fired water heaters. For example, compared to conventional water heater motor/damper assemblies, the installed assembly  10  is more aesthetically pleasing, with the housing  58  being centered between the cold and hot water pipes  28  and  30  (see  FIGS. 1 and 5 ) and hiding the motor  42  and shaft  44  portions of the assembly. The configuration of the support plate structure  32 , coupled with its use of the collar  46 , provides a high degree of support rigidity and alignment precision for the motor  42  and the shaft  44  relative to the damper member  56  which substantially eliminates skewing of the damper member resulting in misalignment of and leakage past the damper. Further, the use of the assembly base plate opening  50  that complementarily receives an upper end portion of the flue  24  provides for repeatable precise manufacturing placement of the motor/drive assembly  10  on the top end of the water heater  16 . Also, the protective enclosure of the motor  42  and the shaft  44  within the housing  58  substantially reduces the possibility of shipping and handling damage of the shaft  44  which would adversely affect the precise motor/shaft/damper alignment advantageously provided by the use of the motor/damper assembly  10 . 
         [0023]    The foregoing detailed description is to be clearly understood as being given by way of illustration and example only, the spirit and scope of the present invention being limited solely by the appended claims.