Patent Publication Number: US-9885477-B2

Title: Semi-submersible gas burner

Description:
TECHNICAL FIELD 
     The present invention relates to fire effect systems and, in particular, to a semi-submersible gas burner assembly for use in fountains and other artificial water features. 
     BACKGROUND 
     Gas burner assemblies used for producing fire effects in fountains, ponds, and other water features typically deliver a combustible gas, such natural gas or propane, to one or more nozzles or frits disposed beneath the surface of the water. Such burner assemblies may be match-lit or may include an electronic ignition module. Electronic ignition modules provide a pilot gas nozzle and an ignition source, such as a glow plug or hot wire igniter, disposed above the surface of the water, and operate during start-up in order to ignite first the pilot, then gas emerging from the water via the submerged nozzles or fits. Assemblies also commonly include a thermocouple, thermopile, or other sensor that senses when the burner assembly has been ignited. The output of the sensor is used to stop the flow of gas if the burner assembly blows out or otherwise becomes extinguished, and also may be used to control operation of the pilot gas nozzle and ignition source in any electronic ignition module (to provide an intermittent or interrupted pilot light feature). The burner assembly may include one or more mesh screens which surround the pilot gas nozzle, sensor, and other components to mechanically protect those components. Systems known to the applicant require a minimum gas supply pressure of at least 2.0 psig, which is an elevated delivery pressure in comparison to the 6-14 inch water column (0.25-0.5 psig) gas pressures commonly employed as “standard pressure” in residential (in-home) gas distribution. 
     Existing gas burner assemblies appear to rely upon high gas supply pressures and high nozzle outputs to both push fuel through the submerged nozzles or fits and maintain a flame in outdoor conditions. Notably, ANSI standard Z21.97 and corresponding CSA standard 2.41 require that systems with flame sensors light and remain burning in a 10 mph horizontal breeze. But such gas supply pressure requirements are frequently incompatible with existing residential gas supplies, which although optionally upgradable to 2.0 psig service at the service entry/gas meter would also require the installation of in-line pressure regulators for each of the residence&#39;s “standard pressure”-rated appliances. Finally, common residential gas distribution piping may cause substantial pressure losses at the gas flow rates required to supply a high BTU, remotely located device such as patio or in-yard installed fire-on-water feature, requiring the replacement of existing small diameter piping, the installation of new or replacement large diameter piping, and careful evaluation of the number of piping elbows and bends necessary to reach the desired feature location. 
     SUMMARY 
     The present application discloses a new semi-submersible gas burner assembly which is operable at “standard” residential gas distribution pressures of 0.5 psig or less. The gas burner assembly includes a tubular void former which provides combustion air to an internal pilot chamber as well as to an external flame retention chamber that is fed by a submerged gas port. The gas burner assembly further includes a lid that provides a pair of depending peripheral skirts in order to create a tortuous path for combustion air drawn in from proximate the surface of the water. The combination of the tubular void former and the lid defines a external flame retention chamber, with the internal pilot chamber providing enhanced start-up capabilities in gentle-to-moderate breeze conditions, the external flame retention chamber providing enhanced blow-out resistance in strong breeze conditions, and the peripheral skirts shielding the flame retention chamber while providing a path for flame propagation back to the open surface of the water. 
     According to a first aspect, a semi-submersible gas burner assembly includes a tubular void former having a proximal end, a distal end, and a nominal waterline defining a plane disposed between the proximal and distal ends. The gas burner assembly further includes a lid engageable with the distal end of the tubular void former, the lid including an inner peripheral skirt disposed outside of and spaced apart from the tubular void former, the inner peripheral skirt projecting toward the plane when the lid is engaged with the tubular void former, an outer peripheral skirt disposed outside of and spaced apart from the inner peripheral skirt, the outer peripheral skirt projecting toward and past the plane when the lid is engaged with the tubular void former, and a distal surface substantially closing off the area of the lid bounded by the inner peripheral skirt. The gas burner assembly yet further includes at least one gas manifold arm extending through and outward from a sidewall of the tubular void former, with at least one gas port formed in the outward portion of the gas manifold arm proximate the sidewall of the tubular void former. The sidewall of the tubular void former includes a communicating aperture disposed between the distal end of the tubular void former and the plane, the communicating aperture fluidly interconnecting the interior of the tubular void former with a flame retention chamber defined by the sidewall of the tubular void former, the distal surface of the lid, the inner peripheral skirt, and the nominal waterline. 
     According to a second aspect, a fire effect system comprises a bowl with nominal waterline, a passage disposed below the nominal waterline, and a semi-submersible gas burner assembly sealingly engageable with the passage. The semi-submersible gas burner assembly includes a tubular void former having a proximal end engaging the bowl about the passage and an opposing distal end. The assembly further includes a lid engageable with the opposing distal end, the lid including an inner peripheral skirt disposed outside of and spaced apart from the tubular void former, the inner peripheral skirt projecting toward the nominal waterline when the lid is engaged with the tubular void former, an outer peripheral skirt disposed outside of and spaced apart from the inner peripheral skirt, the outer peripheral skirt projecting toward and past the nominal waterline when the lid is engaged with the tubular void former, and a distal surface substantially closing off the area of the lid bounded by the inner peripheral skirt. The gas burner assembly yet further includes at least one gas manifold arm extending through and outward from a sidewall of the tubular void former, with at least one gas port formed in the outward portion of the gas manifold arm proximate the sidewall of the tubular void former. The sidewall of the tubular void former includes a communicating aperture disposed between the distal end of the tubular void former and the nominal waterline, the aperture fluidly interconnecting the interior of the tubular void former with at least one flame retention chamber defined by the sidewall of the tubular void former, the distal surface of the lid, the inner peripheral skirt, and the nominal waterline of the bowl. 
    
    
     
       BRIEF SUMMARY OF THE FIGURES 
         FIG. 1A  is a perspective view of an embodiment of the semi-submersible gas burner assembly, oriented towards the distal end of the assembly. 
         FIG. 1B  is a perspective view of the embodiment of  FIG. 1A , omitting the engageable lid in order to show other details of the tubular void former and contents. 
         FIG. 2  is a perspective view of the embodiment of  FIG. 1A , oriented towards the proximal end of the assembly. 
         FIG. 3  is a top view of the embodiment. 
         FIG. 4  is a bottom view of the embodiment. 
         FIG. 5  is a first side view of the embodiment, including a cut-away view of the tubular void former and lid in order to show other details of the burner assembly and lid. 
         FIG. 6  is a second side view of the embodiment, rotated by 90 degrees, including a cut-away view of the engagable lid in order to show other details of the tubular void former and lid. 
         FIG. 7  is a side view of the embodiment installed within an artificial water feature. An exemplary bowl is shown in a side, cut-away view. 
     
    
    
     DETAILED DESCRIPTION 
     Referring initially to  FIGS. 1A, 1B, and 2 , an exemplary embodiment of a semi-submersible gas burner assembly  100  is shown. The burner assembly  100  is based upon a tubular void former  110  having a proximal end  120 , a distal end  130 , and a nominal waterline “W.” In some embodiments, a plane  111  defined by the nominal waterline “W” may be indicated by a marking provided on the tubular void former  110  itself. In other embodiments, the axial location of the plane  111  and the nominal waterline “W” may be defined by a measurement, such as a distance below the distal end  130 , a distance below or above a portion of a separable lid  140  (e.g., distal or proximal ends of an outer peripheral skirt  144 ), a distance above a gas manifold arm  150 , or a similar measurement that may be provided in printed literature accompanying the assembly  100 , printed links to electronic literature made available through (for example) the internet, specifications provided to or made available to prospective distributors and/or customers, or the like. The plane  111  and nominal waterline “W” are disposed between the proximal and distal ends  120 ,  130  so that, in use, the distal end  130  and certain communicating apertures (discussed below) will be disposed above the waterline of a water feature. The plane  111  is preferably perpendicular to the longitudinal axis of the tubular void former  110 , but may be angled with respect to it if the void former is configured for non-vertical installation. The tubular void former  110  is otherwise defined by a sidewall  112  which is shown with a tapering, square cross section, but which in other embodiments may have a tapering or non-tapering circular, triangular, rectangular, or other closed cross section. For sake of clarity, the cross section is preferably a regular geometric shape, but may be an irregular shape and may change, even substantially, between the proximal and distal ends  120  and  130  so long as it defines a continuous and preferably continuously hollow tube. The proximal end  120  may include a proximal flange  122 , shown for illustrative purposes as an outwardly projecting flange, for sealing engagement with the bottom of an artificial water feature such as a fountain. The proximal flange  122  may include a plurality of apertures  124  for receiving fasteners (not shown) for securing the flange  122  and tubular void former  110  against the structure of the water feature, but it will be understood that that the flange  122  could be welded, adhered, clamped, or even in some configurations screwed or bayonet-connected to a mount disposed around the passage. The interior of the tubular void former  110  consequently forms a void within the water feature which may house an electronic ignition module  114 , including a pilot gas nozzle  115 , ignition source  116 , and sensor  117 , as well as convey combustion air from the base or lower portions of the water feature. Frequently such locations will offer a ready supply of becalmed and oxygenated combustion air. 
     The burner assembly  100  further includes a separable lid  140  configured to engage with the distal end  130  of the tubular void former  110 . The lid  140  includes an inner peripheral skirt  142  that is disposed outside of and spaced apart from the outer surface of the tubular void former  110 . As shown in  FIG. 2 , the inner peripheral skirt  142  may in fact contact the corners of the void former  110  at the distal end  130 , but in general is spaced apart from the sidewall  112  at that distal end. The inner peripheral skirt  142  could alternately be entirely spaced apart from the outer surface of the tubular void former  110 , which would produce greater interconnection of surrounding flame retention chambers (discussed below). The lid  140  further includes an outer peripheral skirt  144  disposed outside of and spaced apart from the inner peripheral skirt  142 . The outer peripheral skirt  144  may be connected to and supported by the inner peripheral skirt via a plurality of support arms  145  arrayed between the two or, less preferably, by a rigid mesh or perforated material. The lid  140  yet further includes a distal surface  146  substantially closing off an the area  147  of the lid bounded by the inner peripheral skirt  142 . For sake of clarity, substantially as used in this context permits the inclusion of a plurality of exhaust apertures  148 . The plurality of exhaust apertures  148  should constitute less than 14% and, preferably, less than 7%, of the area  147 . 
     The lid  140  combines with the tubular void former  110  to form shielded combustion chambers at the distal end  130 . A first, a pilot combustion chamber  132  disposed within the tubular void former  110 , contains the pilot flame produced by the pilot gas nozzle  115 . Combustion air may be drawn from within the tubular void former  110 . Thus the pilot flame is shielded from the wind by the structures of the lid  140  and the sidewall  112  of the tubular void former  110 , as well as the body of the electronic ignition module  114 . A second, a flame retention chamber  134  disposed around the tubular void former, contains a flame produced by the combustion of gas from a submerged gas port disposed proximate the sidewall  112  of the tubular void former (discussed below). The inner peripheral skirt  142  projects from the lid  140  (as shown, the distal surface  146 ) toward the plane  111 , but with a proximal end  143  of skirt  142  terminating short of the plane when the lid is engaged with the tubular void former  110 , so that the proximal end  143  will be positioned above the nominal waterline. Combustion air is drawn from outside the lid  140 , between the inner peripheral skirt  142  and the plane  111 , and into a chamber  134  defined by the sidewall  112 , the distal surface  146 , the inner peripheral skirt, and an actual waterline which, in use, should generally correspond to the plane  111  and nominal waterline “W.” As best shown in  FIG. 5 , in order to prevent blow-out the outer peripheral skirt  144  projects from the lid  140  (as shown, support arms  145  of lid  140 ) toward and past the plane  111  when the lid is engaged with the tubular void former  110 , so that a proximal end of skirt  144  will be positioned below the nominal waterline. Thus, in general, combustion air drawn from outside the lid  140  must follow a tortuous path which passes between the inner and outer peripheral skirts  142  and  144 , around the proximal end  143  of the inner peripheral skirt, and into the flame retention chamber  134 . However, to prevent combustion air starvation in strong breeze conditions, it may be advantageous to include a plurality of inlet apertures  149  within the outer peripheral skirt  144  itself. The inlet apertures  149  are preferably disposed proximate the distal end of the skirt  144  (versus the proximal end  145 ) to maintain a tortuous path, but reduce the tendency of a strong breeze to produce a low pressure zone next to the inner peripheral skirt  142  in the lee of the outer peripheral skirt  144 . Specifically, the inlet apertures  149  may be positioned distally of the proximal end  143  of the inner peripheral skirt  142  so that wind-driven air will impact the inner peripheral skirt, thus forcing incoming combustion air to divert toward the waterline, around the proximal end of the inner peripheral skirt, and into the chamber  134 . Since the wind does not have direct access to the protected chamber  134 , the retained flame cannot be easily extinguished. 
     The lid  140  includes a plurality of exhaust apertures  148  which serve to allow exhaust products to escape the lid  140 . A least one exhaust aperture is disposed adjacent the pilot gas nozzle  115  and ignition source  116 . As shown in  FIGS. 1A and 1B , an exhaust aperture  148   a  may be disposed in the lid  140  at a radial location outside the location of sidewall  112  of the tubular void former  110 , adjacent to a communicating aperture  136  disposed in the sidewall  112  of the tubular void former which is directly adjacent to the pilot gas nozzle  115 . The exhaust aperture  148   a  is preferably a single ⅝″ by ½″ opening, +/−⅛″ but may be closely packed collection of openings (individual openings or a mesh) of equivalent opening area. This is sufficient to prevent extinguishment of the pilot light without unduly exposing the pilot light to the wind. The radial offset further shields the pilot gas nozzle  115  and ignition source  116  from rain, snow, etc. As least one other exhaust aperture  148  is formed in the distal surface  146 , adjoining the flame retention chamber  134 . As shown in  FIG. 1B , an exhaust aperture  148  is positioned in distal surface  146  directly above a flame retention chamber  134 . The exhaust aperture  148  is preferably comprised of a plurality of perforations which serve to diffuse air potentially entering the flame retention chamber due to turbulence or a general downward flow. However, the exhaust aperture  148  could be a single opening like aperture  148   a  or an opening provided with a mesh (not shown). As shown in  FIG. 1B , when the inner peripheral skirt  142  contacts the corners of the void former  110  at the distal end  130 , there could be said to be multiple flame retention chambers  134 , although it will be noted that since the inner peripheral skirt  142  does not project proximally past the plane  111  and nominal waterline “W” (as shown in  FIGS. 5-6 ), such chambers  134  are not actually isolated from each other and may intercommunicate close to the waterline. As also shown in  FIG. 1B  near the apertures  148  and  148   a , the lid  140  may include depending tabs which engage the distal end  130  of the tubular void former  110  to orient and locate the lid with respect to the distal end  140 , the communicating aperture  113 , and any other communicating apertures  135 . 
     At least one communicating aperture  136  is disposed in the sidewall  112  adjacent the flame retention chamber  134 , between the distal end  130  of the tubular void former  110  and the plane  111 /nominal waterline “W.” Preferably there will be multiple communicating apertures  136  arrayed around the periphery of the distal end  130  of the tubular void former  110 . As indicated by the combination of  FIGS. 1B, 2, and 3 , there may be multiple flame retention chambers  134 , with at least one communicating aperture  136  adjoining each flame retention chamber  134 , preferably adjacent to exhaust apertures  148  in the lid  140 . Communicating aperture(s)  136  may be comprised of a plurality of perforations which may diffuse air transiting the sidewall  112  from the interior of the tubular void former  110  to the flame retention chamber  134  or vice versa. However, communicating aperture(s)  136  could be single openings, depending slots, or openings or slots provided with a mesh (not shown). The sum of the area of the communicating aperture openings should be greater than the area of the exhaust aperture  148   a . Preferably the periphery of the distal end  130  is configured to be substantially open above the nominal waterline “W,” i.e., capable of supplying sufficient combustion air to the pilot flame but capable of resisting spill-over of water due to ordinary disturbances such as or ripples caused by the wind or small objects thrown into the water. The communicating aperture(s)  136  may supply combustion air to the flame retention chamber  134  from inside the tubular void former  110  and/or provide an additional path for exhaust products from the pilot flame to exit from the tubular void former  110  under the distal surface  146  of the lid  140 . Where there are multiple flame retention chambers, the communicating apertures  148  may also provide an additional path for flame propagation between flame retention chambers, as well as between the pilot flame and any unlit flame retention chamber. 
     The gas burner assembly  100  has at least one gas manifold arm  150  extending through and outward from the sidewall  112  of the tubular void former  110 . As best seen in  FIG. 3 , a gas manifold arm  150  may extend radially outward from the sidewall  112 , but in other embodiments could extend in any outwardly oriented path from the sidewall. The gas manifold form  150  extends outward from a point  152  between the plane  111 /nominal waterline “W” and proximal end  120 . In preferred embodiments, a proximal side  154  of the gas manifold arm  150  is disposed about ½″ from the plane  111  and nominal waterline “W+/−¼”. In other embodiments, the proximal side  154  may be disposed about 1″ form the plane  111  and nominal waterline “W”+/−¼″, or potentially, but less advantageously, at greater separation distances, since the separation distance will affect the combustible gas pressure that must be present at the burner assembly, and may preclude long, standard diameter piping connections to in-home distribution systems operated at the low end of “standard pressure.” The gas manifold arm  150  may subsequently form any of a variety of closed or open, regular or irregular shapes. Multiple gas manifold arms  150  may extend through and outward from the sidewall  112  of the tubular void former  110  and may form separate or, preferably, interconnected portions of such shapes, for example, the illustrated circular burner shape. 
     The gas manifold arm  150  is connected to a gas supply line  160  disposed within the tubular void former  110 . As shown in  FIGS. 4 and 5 , the gas supply line may run from a point proximally disposed from the plane  111 /nominal waterline “W,” preferably from at least the proximal end  120  of the tubular void former  110 , to about the distal end  130  of the tubular void former, and then connect to gas manifold arms  150 . As shown, the gas supply line  160  runs back to a the axial position of the gas manifold arms  150  and formed shape, but the gas manifold arms  150  could be formed so as to meet the gas supply line  160  distally from the plane  111 /nominal waterline “W.” These configurations serve to produce a gas break, preventing any water which infiltrates that gas manifold arm from flowing into the gas connection through the gas supply line  160 . 
     The gas manifold arm  150  includes at least one gas port  156  disposed proximate the sidewall  112  of the tubular void former  110 . Proximate in this context means at or inside the axially projected radial position of the inner peripheral skirt  142 , such that gas existing the gas port  156  will generally emerge from the water of the water feature within the radial bounds of the outer and inner peripheral skirts  144 ,  142 . Accordingly, gas expelled from the at least one gas port  156  supplies fuel to the flame retention chamber  134 . Where multiple gas manifold arms are present, each arm may include a gas port  156  disposed proximate the sidewall, and may thus supply fuel to the flame retention chamber  134  at multiple locations, or to each of several semi-separated flame retention chambers  134 . The more outward portions of the gas manifold arm  150  may include a plurality of other gas ports  158  disposed remotely from the sidewall  112  (outside the axially projected radial position of the inner peripheral skirt) in order to supply fuel for an open flame to be maintained on the open surface of the water of the water feature. The gas port(s)  156  and  158  are preferably holes having a diameter of about 0.06″+0.04″/−0.03″. The small diameter of the gas ports  156  and  158  uses the surface tension of water in the water feature to resist infiltration of water within the gas manifold arm. Preferably, as shown in  FIGS. 2 and 4 , gas ports  156  and  158  are disposed on the proximal side  154  of gas manifold arm(s)  150 . The proximal placement of the gas ports further resists infiltration of water within the gas manifold arm by resisting bulk migration of the combustible gas out of the ports, e.g., bubbling, after the gas burner  100  has been shut off and is essentially quiescent. In the illustrated embodiment, having a generally circular outward configuration, gas ports  158  may pitched inwards toward a central longitudinal axis of the burner assembly such that most of the released fuel will tend to emerge from the water within the area bounded by the manifold arms  150 . The inward pitch will tend to concentrate the released fuel in proximity to the flame retention chamber(s)  134 , reducing the proportion of fuel that might escape combustion. 
     The gas burner assembly may optionally include a water manifold  170  for use in circulating water within a water feature. As illustrated, the water manifold  170  forms a tee fitting having an inlet  172  (shown in  FIGS. 2 and 4 ) disposed within the tubular void former  110  and a pair of opposed outlets  174  disposed in the sidewall  112  of the tubular void former. It will be appreciated that the number of inlets  172  and outlets  174  may vary, and that in use the outlets  174  may be coupled to submerged tube diffusers, nozzles, jets, or the like as well as surface sprayers, nozzles, jets, etc. Water manifold  170  would, in use, be connected to an external pump or other pressurized supply of water to provide for either basic circulation of water within a water feature or aesthetically pleasing water effects. 
     As shown in  FIG. 7 , the semi-submersible gas burner assembly  100  may be combined with a bowl  200  to form an operable fire-on-water feature. The bowl  200  has a nominal waterline “W” and an passage  210  disposed below the nominal waterline. The passage  210  may be a simple aperture or an aperture surrounded by a fitting  212  such as flush or raised flange fitting, a threaded fitting, a bayonet-connection fitting, etc. Fitting  212  is shown for illustrative purposes as a flush flange for mutual engagement with the flange  122  of the gas burner assembly  100 . The water level in the bowl may be passively maintained at the level of the nominal waterline “W,” but preferably is actively maintained at the level of the nominal waterline via a pump, which may add water via outlets  174 . The water level may be maintained in an active system by a drainage standpoint open at the nominal waterline, or as shown by one or more scuppers  220  which permit water to overflow from the bowl  200  and into a collector pool or, more typically, a sump disposed under a permeable cover. The combination advantageously permits the plane  111  and intended nominal waterline of the gas burner assembly  100  to match by design the nominal waterline “W” of the bowl  200 , rather than require the use of spacers, adapters, extensions, and the attendant additional gaskets or seals generally required to control leakage from the bowl  200 . For sake of clarity, nominal waterline “W” is shown at an exaggerated distance above the base of the scuppers  220 , however it is noted that with pumping and active maintenance of the water level the operating waterline will actually be higher than the base of any scuppers or standpipe, 
     The embodiment of the invention shown in the drawings and described above is but one example of numerous embodiments that may be made from the variations, modifications, and alternatives discussed herein. It is the applicant&#39;s intention that the scope of the patent issuing herefrom will be limited only by the scope of the claims and specific definitions provided herein.