Patent Publication Number: US-6910478-B2

Title: Direct-vent fireplace configurable for top venting or rear venting

Description:
BACKGROUND OF THE INVENTION 
   The present invention relates in general to fireplace structures and, in particular, to direct-vent, gas fireplace structures. More specifically, the present invention relates to a direct-vent fireplace that may be configured in one arrangement for top venting and, in an alternate arrangement, for rear venting. The alternate arrangements are enabled by the combination of an inlet cover plate and outlet elbow. The arrangement of this inlet cover plate and outlet elbow relative to the remainder of the fireplace structure determines whether the fireplace will be a top venting unit or a rear venting unit. 
   U.S. Pat. No. 6,295,981 issued Oct. 2, 2001 to Beal et al. addresses a problem associated with some direct-vent, gas fireplaces namely, the difficulty in selectively and easily venting combustion gases in either a horizontal or a vertical direction. In the context of the present invention, the horizontal direction would correspond to a rear vent arrangement while the vertical direction would correspond to a top vent arrangement. The &#39;981 patent explains some of the realities of conventional fireplace designs and discusses some of the efforts of other designers (inventors) in the following manner. 
   Gas fireplaces of conventional design typically utilize a source of combustion air from the room being heated. This lowers the efficiency of the gas fireplace because a portion of the heated air in the room is drawn into the combustion chamber and exhausted up the chimney. It is known to provide separate ducting from the outside ambient environment to the combustion chamber to increase the efficiency of the fireplace. The ducted air provides a source of oxygen for combustion in the combustion chamber and decreases the amount of air from the room being heated which is exhausted up the chimney. Such ducting, however, requires additional materials and labor to install. 
   It is also known in the art to utilize concentric flue pipes to exhaust combustion products to the outside environment and supply combustion air from the outside environment. Such fireplaces are termed “direct-vent” fireplaces and are disclosed, for example, in U.S. Pat. No. 4,793,322 (Shimek I) and U.S. Pat. No. 4,909,227 (Rieger). A direct-vent fireplace has the advantage of utilizing a common concentric flue pipe assembly to both exhaust combustion products from and supply combustion air to the combustion chamber. Moreover, only a single opening need be cut through an exterior wall of a house to accommodate the concentric flue pipe assembly. 
   In general, a direct-vent fireplace has a first pipe with a diameter larger than and disposed concentrically around a second pipe. The duct formed by the second pipe is used to convey exhaust products from the combustion chamber to the outside environment. The annular space formed between the first and second pipes defines a fresh air conduit through which combustion air flows from the outside ambient environment into the combustion chamber. 
   A problem with direct-vent gas fireplaces is that the concentric flue pipe assembly cannot be easily vented in both a horizontal or vertical direction. Shimek I and Rieger disclose direct-vent fireplaces which respectively connect the concentric flue to the rear wall and top wall of the fireplace. A concentric flue attached to the rear wall of the fireplace may be easily extended through an adjacent sidewall of the house. However, if it is desirable to exhaust the concentric flue in a vertical direction, the fireplace must be moved forward a sufficient distance to allow coupling of a right angle concentric pipe elbow. Thus, additional floor space is required to accommodate the projected footprint of the fireplace and concentric flue pipe assembly. 
   A concentric flue pipe assembly attached to the top of a direct-vent fireplace has a similar problem when it is desired to vent the concentric fluid in a horizontal direction (see, e.g., Rieger at Col. 1, lines 23–32). That is, the fireplace must be moved forward a sufficient distance to allow coupling of a right angle concentric pipe elbow. 
   Because of two possible installation configurations, i.e., vertical or horizontal venting of the concentric flue pipe assembly, it is necessary with conventional direct-vent fireplaces to provide two totally different configurations. That is, for relatively close placement of the fireplace adjacent the outside wall of the house, it is necessary to provide one configuration allowing attachment of the concentric flue pipe assembly to the back of the fireplace for horizontal venting, and a second configuration allowing attachment of the concentric flue pipe assembly to the top of the fireplace for vertical venting. The necessity to provide two different configurations increases inventory requirements at the factory. Reference can be made, for instance, to U.S. Pat. No. 5,320,086 (Shimek II) regarding the same. Shimek II is directed to a single fireplace construction that could be used in both a vertical venting configuration (i.e., relatively straight upwardly from the fireplace) of a horizontal venting configuration (i.e., relatively straight out from the back of the fireplace). 
   Moreover, such fireplaces should be equipped with a mechanism or process that enables one type of venting (e.g., vertical), while preventing the other type of venting (e.g., horizontal). This would allow any exhaust matter to escape the fireplace via the selected venting type, while preventing the same from escaping via the non-selected type. 
   Accordingly, it would be desirable to have a fireplace that overcomes the above disadvantages. 
   The perceived improvement offered by the &#39;981 patent is to first provide both a top port ( 40 ) and a rear port ( 41 ). These two ports communicate with an outlet box ( 44 ) extending from the combustion chamber ( 11 ). Each port includes a bottom panel ( 48 ) defining a circular hole ( 49 ). Next, according to the &#39;981 patent, an air inlet pipe member ( 60 ) and a separate air outlet pipe member ( 61 ) are provided. Included as part of outlet pipe member ( 61 ) is a plate portion ( 63 ) that attaches to the bottom panel ( 48 ). Inlet pipe member ( 60 ) then is assembled in a concentric manner relative to outlet pipe member ( 61 ). Inlet pipe member ( 60 ) includes an integral cover plate portion ( 67 ) that functions to close off the non-selected port. 
   The present invention discloses a structural configuration that enables selective fireplace conversion to either horizontal (rear) venting or vertical (top) venting. Rather than using an outlet pipe member with a cumbersome plate portion, the present invention uses two separate cover plates. The fireplace is configured with an inner panel set at approximately 45 degrees relative to the horizontal and vertical directions and defines a vent port that is in direct flow communication with the combustion chamber. One feature of the present invention is the use of an outlet elbow. One of the unexpected benefits of this design is an increase in velocity of the heated gas exiting the combustion chamber. This increase in velocity in turn increases the intake air flow thereby increasing the heat output and flame performance of the fireplace. Moreover, this structure provides the ability to attach the inlet/outlet subassembly in a first orientation or arrangement for vertical venting and in a second orientation or arrangement for horizontal venting, while using the same vent port. 
   The convenience and simplicity of this structure, according to the present invention, is seen as a novel and unobvious advance in the art. 
   SUMMARY OF THE INVENTION 
   A direct-vent fireplace configurable into a top venting unit in one arrangement and configurable into a rear venting unit in another arrangement according to one embodiment of the present invention comprises a combustion chamber, an outer enclosure enclosing at least a portion of a combustion chamber, the outer enclosure including a rear panel defining a rear opening and including a top panel defining a top opening, a vent panel positioned between the combustion chamber and the outer enclosure, an outlet elbow attached to the vent panel and arranged in flow communication with the combustion chamber, and an inlet cover plate surrounding a portion of the outlet elbow that extends through the outer enclosure, wherein the outlet elbow portion extends through the rear opening for achieving the rear venting arrangement and the outlet/elbow portion extends through the top opening for achieving the top venting arrangement. 
   One object of the present invention is to provide an improved direct-vent fireplace. 
   Related objects and advantages of the present invention will be apparent from the following description. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a diagrammatic, perspective view of a direct-vent, gas fireplace, without its outer enclosure, according to a typical embodiment of the present invention. 
       FIG. 2  is a diagrammatic, front elevational view of a fireplace assembly based in part on the  FIG. 1  fireplace. 
       FIG. 3  is a diagrammatic, side elevational view, in full section, corresponding to the  FIG. 2  fireplace arrangement. 
       FIG. 4  is a diagrammatic, top plan view of the  FIG. 2  fireplace arrangement. 
       FIG. 5  is a diagrammatic, front elevational view of a fireplace assembly based in part on the  FIG. 1  fireplace. 
       FIG. 6  is a diagrammatic, side elevational view, in full section, corresponding to the  FIG. 5  fireplace arrangement. 
       FIG. 7  is a diagrammatic, top plan view of the  FIG. 2  fireplace arrangement. 
       FIG. 8  is an exploded view of a direct-vent, gas fireplace, without its outer enclosure, depicting the attachment of the outlet elbow. 
       FIG. 9  is a partially exploded view of the  FIG. 8  fireplace assembly with enclosing panels included, depicting the attachment of cover plates to the enclosing panels. 
       FIG. 10  is a partially exploded view of the  FIGS. 8 and 9  fireplace assembly, with an outer enclosure added. 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   For the purposes of promoting an understanding of the principles of the invention, reference will now be made to the embodiments illustrated in the drawings and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended, such alterations and further modifications in the illustrated device, and such further applications of the principles of the invention as illustrated therein being contemplated as would normally occur to one skilled in the art to which the invention relates. 
   Referring to  FIG. 1 , there is illustrated a gas fireplace  20  that is constructed and arranged for direct-venting of combustion gases. Fireplace  20  is diagrammatically illustrated and includes various sheet metal panels that provide, among other structural components, a base  21 , rear panel  22 , and vent panel  23 . A combination of sheet metal panels are constructed and arranged in order to create the illustrated fireplace combustion chamber  24 . The front wall  25  of the fireplace  20  is typically a combination of metal and glass, serving both decorative and performance functions. The actual construction details regarding the front wall  25 , base  21 , and combustion chamber  24  are considered to be secondary to the primary points of focus of the present invention. Accordingly, a majority of the discussion regarding the present invention is directed to rear panel  22  and vent panel  23 , as well as to the outer enclosure  28  that cooperates with fireplace  20  in order to create a fireplace assembly  32 . Two slightly different fireplace assemblies or arrangements are illustrated according to the present invention. A top or vertical venting arrangement is diagrammatically illustrated in  FIGS. 2–4 . A rear or horizontal venting arrangement is diagrammatically illustrated in  FIGS. 5–7 . The partially exploded views of  FIGS. 8 ,  9  and  10  illustrate the sequential build up of panels to complete the fireplace assembly  32  for a rear venting arrangement. In both the top venting and rear venting arrangements, it will be noted that vent panel  23  remains in the same assembled location and orientation with an approximate 45 degree incline relative to horizontal and vertical directions. Anticipating a normal or conventional fireplace installation, it would be expected for the front wall  25  of the fireplace to be substantially vertical and substantially parallel to the rear panel  38  of the outer enclosure  28 . Likewise, it would be expected that the base  21  would be positioned so as to be substantially horizontal and substantially parallel to the top panel  36  of the outer enclosure  28 . 
   The primary focus of the present invention is directed to a cooperating combination of an inlet component (cover plate)  30  and an outlet component (outlet elbow)  31 , referred herein as “subassembly”  29 . More specifically, the focus of the present invention is directed to the options for attaching the outlet elbow  31  to vent panel  23 . The inlet and outlet components work together as an unit and as part of the fireplace assembly  32  that includes fireplace  20 , interior sheet metal panels and outer enclosure  28 . Since the fireplace assembly  32  includes the same grouping of component parts, albeit in two different arrangements, reference number  32  is used for both arrangements. As is illustrated, the inlet cover plate  30  includes a mounting plate  30   a  and an integral cylindrical sleeve  30   b . The outlet elbow  31  includes a mounting plate  31   a  and an integral elbow conduit  31   b , having an approximate 45 degree bend (i.e., 135 degree included angle). 
   Vent panel  23  is positioned between the combustion chamber  24  and the outer enclosure  28 . The vent panel  23  is angled approximately 45 degrees relative to the top panel  36  and rear panel  38 . This orientation represents the normal or expected orientation for the fireplace assembly  32  within the structure where it will be installed. 
   Vent panel  23  includes a generally square opening  23   a  that is constructed and arranged to receive mounting plate  31   a  of outlet elbow  31 . The specific style of attachment is not critical so long as plate  31   a  closes off opening  23   a , except for the venting of combustion gas by way of conduit  31   b . One or more removable fasteners  34  are used to secure plate  31   a  to vent panel  23 . 
   In the  FIG. 1  illustration, the mounting plate  31   a  of subassembly  29  is attached directly to vent panel  23  for the venting of combustion gas from the rear of the fireplace assembly  32  (see  FIGS. 5–7 ). By turning the outlet elbow  31  180 degrees, the fireplace assembly  32  is configured for the venting of combustion gas from the top of the fireplace assembly  32  (see  FIGS. 2–4 ). Regardless of how the fireplace assembly  32  may be initially configured for the intended installation, it can be readily changed to the other configuration or arrangement by simply removing the fasteners  34 , turning the mounting plate  31   a  180 degrees, and reinserting the removable fasteners  34 . This change in configuration not only changes the fireplace assembly  32  from a rear vent arrangement to a top vent arrangement (or vice versa), but it also changes where the mounting plate  30   a  of the inlet cover plate  30  should be affixed. Additionally, this change in arrangement changes which portion of the outer enclosure, either the rear panel  38  or the top panel  36 , is used for exhausting of the combustion gases. 
   The fireplace assembly  32  includes, in combination, the fireplace  20 , interior panels  54  and  55 , the outer enclosure  28 , and the inlet/outlet subassembly  29 . The arrangement of these components and subassemblies is diagrammatically illustrated in  FIGS. 2–7  and as partially exploded views in  FIGS. 8–10 . As illustrated, the outer enclosure  28  includes an opening  35  in top panel  36  and there is a similarly sized and shaped opening  37  in rear panel  38 . The  FIG. 1  configuration for fireplace  20 , corresponding to  FIGS. 5–7  and  8 – 10 , positions the mounting plate  30   a  of inlet cover plate  30  on the intermediate panel  55  at a location (opening  55   a ) that is aligned with opening  37 . The arrangement corresponding to  FIGS. 2–4  positions the mounting plate  30   a  of inlet cover plate  30  on the intermediate panel  54  at a location (opening  54   a ) that is aligned with opening  35 . In  FIG. 4 , plate  30   a  includes a plurality of peripheral mounting (clearance) holes  39  and a cooperating series of internally-threaded inserts  40  (or captured nuts) that are located in panel  54  around the periphery of opening  54   a . A generally concentric relationship is maintained between the conduit  31   b  of outlet elbow  31  and the cylindrical sleeve  30   b  of inlet cover plate  30 . 
   With continued reference to  FIG. 4 , the disclosed design allows mounting plate  30   a  to be positioned through opening  35  and attached to panel  54  by the use of threaded fasteners  59  extending through clearance holes  39  and received by threaded inserts  40 . This leaves opening  55   a  uncovered and, in order to close off this opening and complete fireplace assembly  32 , a cover plate  43  is used and is attached to panel  55  in the same way that plate  30   a  is attached to panel  54 . In fact, as will be clear, not only are the size and shape of openings  54   a  and  55   a  virtually identical, but the number, location, and spacing of the internally-threaded inserts  40  associated with both openings are virtually identical. Openings  35  and  37  are slightly larger than openings  54   a  and  55   a  and are aligned respectively. This means that plate  30   a  can either be positioned over opening  55   a  and attached to panel  55  or positioned over opening  54   a  and attached to panel  54 . Likewise, cover plate  43  can either be positioned over opening  54   a  and attached to panel  54  or positioned over opening  55   a  and attached to panel  55 . It is intended that the inlet/outlet subassembly  29  and cover plate  43  will be used together. 
   From the diagrammatic illustrations of  FIGS. 3 and 6 , it will be seen that the incoming combustion air is represented by arrows  47  and this air flows through the generally annular ring corridor  48  defined by the concentric arrangement of conduit  31   b  and sleeve  30   b . The combustion gases (combustion by-products) are exhausted from the combustion chamber  24  by way of subassembly  29  as represented by flow arrows  49 . Ambient air enters through annular ring corridor  48  as combustion by-products exit as represented by flow arrows  47 . The exit velocity of the combustion gases (combustion by-products) is increased through the arrangement of subassembly  29  and the vent panel  23  creating an initially angled exit of combustion gases through outlet elbow  31 . The exit velocity of the hot gases is increased because of a vertical velocity component. The initial angled exit allows the exit velocity to overcome any resistance created at the elbow. 
   In the exploded views of  FIGS. 8–10 , it is better seen how subassembly  29  is composed and combined with the intermediate panels  54  and  55  and with outer enclosure  28 . Outlet elbow  31  is attached to vent panel  23  by covering the opening  23   a  with the mounting plate  31   a . Mounting plate  31   a  is firmly affixed to panel  23  by passing threaded fasteners  34  through clearance holes  51  in mounting plate  31   a  and into holes  52  in panel  23 . The fasteners  34  are preferably of a type that allows easy insertion and removal in light of the difficulty for an user to manually work with the threaded end during insertion. It is envisioned that a captured nut or threaded insert will be used in holes  52  to receive fasteners  34 . The outlet elbow  31  is positioned in  FIG. 8  for venting of combustion gas from the rear of the fireplace assembly  32 . The vent plate  23  is positioned approximately 45 degrees in relation to the intermediate panels  54  and  55 , top enclosure panel  36 , and rear panel  38 . The outlet elbow bends approximately 45 degrees to provide an initial angled exit for the exhaust gas and either a vertical or horizontal final exit from the fireplace assembly  32 . As mentioned earlier, this arrangement adds a vertical velocity component for the gases during the initial angled exit thereby improving air intake and heat output. 
   Beginning with the  FIG. 8  fireplace subassembly, the next step or layer in the fabrication process is the addition of intermediate sheet metal panels  54  and  55  (see FIG.  9 ). These two panels are horizontal and vertical and are securely joined together and to the remainder of the  FIG. 8  structure. Additional sheet metal panels may be utilized as part of this overall fabrication process in order to construct a strong and secure fireplace. However, with regard to the present invention, the focus will be on the use of the top (intermediate) panel  54  and the rear (intermediate) panel  55 . 
   Top panel  54  includes opening  54   a  that is either closed by cover plate  43  using threaded fasteners  59  (as illustrated) or receives inlet cover plate  30  when a top venting arrangement is selected. Rear panel  55  includes opening  55   a  that either receives inlet cover plate  30  by using threaded fasteners  59  (as illustrated) or receives cover plate  43  when a top venting arrangement is selected. 
   Referring to  FIG. 10 , the outer enclosure  28  is added to the  FIG. 9  structure so as to enclose the fireplace assembly and the intermediate panels. Included as part of enclosure  28  are top panel  36  and rear panel  38 . Panel  36  includes opening  35  that is aligned with opening  54   a . Panel  38  includes opening  37  that is aligned with opening  55   a . The larger opening size for openings  35  and  37  allows the threaded fasteners used for inlet cover plate  30  and for outlet elbow  31  to remain accessible without having to remove the outer enclosure. Depending on the venting arrangement selected, the conduit  31   b  of the outlet elbow  31  extends through the corresponding panels, either panels  54  and  36  for top venting or panels  55  and  38  for rear venting. 
   While the invention has been illustrated and described in detail in the drawings and foregoing description, the same is to be considered as illustrative and not restrictive in character, it being understood that only the preferred embodiment has been shown and described and that all changes and modifications that come within the spirit of the invention are desired to be protected.