Abstract:
The gas tube fryer comprises substantially 90° in-shot burners, burner mounting boxes, a one-piece burner mounting bracket, and a bracket housing, all of which are used in conjunction with heat exchanger tubes, heat transfer baffles, a frypot, and a flue in a fryer. The burner mounting boxes are keyed specifically to the face of the burner, preventing substantial movement of the burners and introduction of ambient air into the heat exchange tubes. Each burner is also keyed to the mounting bracket, also preventing substantial movement and providing easy installation and repair. The ninety-degree orientation of the burners facilitates mixing of the combustion gases, and the burner comprises a screen on its face that helps to ensure maximum burner efficiency.

Description:
CROSS-REFERENCE TO RELATED APPLICATION  
       [0001]     This application claims priority to U.S. Provisional Application Ser. No. 60/729,039, filed on Oct. 21, 2005. 
     
    
     BACKGROUND OF THE INVENTION  
       [0002]     1. Field of the Invention  
         [0003]     The present disclosure relates to gas fryers. More particularly, the present disclosure relates to a gas fryer that utilizes burners and heat exchanger tubes to transfer heat to a cooking medium in a frypot.  
         [0004]     2. Description of the Related Art  
         [0005]     Deep fat tube fryers are well known in the field. These fryers typically include a frypot containing a cooking oil medium and one or more heat exchanger tubes that run through the frypot below the surface of the cooking oil. Burners are typically connected to one end of these heat exchanger tubes and heat the tube so that the heat is transferred to the cooking oil. A flue is usually used on the opposite end of the heat exchanger tube from the burner to discharge the combustion by-products. Often baffles are used inside the heat exchanger tubes to retard the flow of the combustion gasses and thereby increase the rate of heat transfer to the cooking medium. Additionally, the baffles assist in the transfer of heat by conducting heat themselves.  
         [0006]     Due to their use in industrial applications such as fast food restaurants, it is desirable to make these fryers as efficient as possible and easy to service, in order to reduce operating costs. Many conventional fryers, however, have burners that are mounted to the heat exchanger tube in a way that allows the escape of some of the combustion gasses. One other difficulty with conventional deep fat tube fryers is that the burners are rigidly mounted to the heat exchanger tubes, or mounted to the heat exchanger tubes with a number of fasteners. Either of these configurations requires a significant amount of time for service and repair.  
         [0007]     Additionally, many in-shot burners used with heat exchanger tubes are mounted either co-axially with the heat exchanger tubes of the fryer or at an angle downward to the horizontal. Neither of these configurations is desirable. The co-axial orientation often requires that the burner be shorter than what optimal burning conditions would require, due to space limitations. Those burners that use an angled mounting orientation are not desirable because they force the combustion gas down into the heat exchanger tube, against the forces of gravity and/or buoyancy. This is not an ideal condition to facilitate the mixing of the gas fuel with air.  
         [0008]     Typically, burners currently in use employ a cast hole(s) or perforated plate as the burner face leading into the heat exchanger tube. These configurations are undesirable because they decrease the efficiency with which the combustion gasses are mixed and burned.  
         [0009]     Consequently, there is a need for a burner assembly that provides an efficient burn and high heat transfer rate for the fryer, which is convenient and easy to service.  
         [0010]     It is an object of the present invention to provide a burner assembly for a tube fryer that is easy to service and maintain.  
         [0011]     It is a further object of the present invention to provide an increased burning efficiency over the currently available systems.  
       SUMMARY OF THE INVENTION  
       [0012]     A burner assembly of the present invention comprises one or more ninety-degree in-shot burners, one or more burner mounting boxes, a one-piece burner mounting bracket, and a bracket housing, to be used in conjunction with heat exchanger tubes, heat transfer baffles, a frypot and a flue in a fryer.  
         [0013]     Burner mounting boxes are mounted at one end of each heat exchanger tube. The heat exchanger tubes extend through the length of the frypot, below the oil level. The burner mounting boxes are keyed specifically to a burner face, preventing substantial introduction of ambient air into the heat exchanger tubes and thereby increasing burner efficiency. Each burner is also keyed to the one-piece mounting bracket to ensure that the burners are placed in their proper orientation, and to prevent substantial movement of the burner when the fryer is in use or transit.  
         [0014]     The gas is introduced to the burner assembly through a manifold located at the lower end of the burners. It travels up the vertical part of the burner and exits at the top, where the ninety-degree burner face meets the burner mounting box. The gas is ignited at the burner face by a pilot source. The screen covering the burner face is designed to provide a maximum burner efficiency and ease of control by the user.  
         [0015]     Flames and combustion gasses then longitudinally traverse each heat exchanger tube, transferring heat to the tube and heat transfer baffle, heating the surrounding fryer oil bath, and subsequently exhausting out through the frypot flue.  
         [0016]     The above described and other features and advantages of the present disclosure will be appreciated and understood by those skilled in the art from the following detailed description and drawings. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0017]      FIG. 1  shows a rear, left side perspective view of a five-burner assembly, including burners, mounting boxes, and a gas manifold connected to a frypot;  
         [0018]      FIG. 2  shows a side view of the assembly shown in  FIG. 1 ;  
         [0019]      FIG. 3  shows a side view of a burner;  
         [0020]      FIG. 4  shows a front view of the burner of  FIG. 3 ;  
         [0021]      FIG. 5  shows a front, right-side perspective of the burner of  FIG. 3 ;  
         [0022]      FIG. 6  shows a rear view of a five-burner assembly, including the burners, the mounting boxes, and the manifold;  
         [0023]      FIG. 7  shows a front view of the components shown in  FIG. 6 ;  
         [0024]      FIG. 8  shows the burner assembly of  FIG. 6 , further comprising a mounting bracket that connects the burners to a frypot;  
         [0025]      FIG. 9  shows a rear view of the assembly shown in  FIG. 8 ;  
         [0026]      FIG. 10  shows a side view of the assembly shown in  FIG. 8 ;  
         [0027]      FIG. 11  shows an exploded view of the assembly shown in  FIG. 8 ;  
         [0028]      FIG. 12  shows a rear, left-side perspective view of the baffles that are placed inside the heat exchanger tubes of fryer; and  
         [0029]      FIG. 13  shows a side view of the baffles shown in  FIG. 12 . 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0030]     Referring to  FIGS. 1 and 2 , an assembly of five burners  10 , gas manifold  30 , heat exchanger tube  70 , heat transfer baffle  80 , flue  90 , and frypot  95  are shown. Gas manifold  30  can have manifold testing port  31 , which during maintenance can be used to ensure that a proper amount of gas is flowing through the manifold at an adequate pressure. Manifold testing port  31  remains sealed during fryer operation. Gas manifold  30  also has gas inlet  35 . When the burner assembly is in use, combustion gas is introduced into gas manifold  30  through gas inlet  35  and travels up through burners  10 , as is discussed in further detail below.  
         [0031]     Referring to  FIGS. 3, 4 , and  5 , an enlarged view of burner  10  is shown. The body of burner  10  is formed from one continuous sheet of metal, which in the present embodiment is aluminized steel. The present invention, however, contemplates the use of other materials to form burner  10 , such as galvanized or stainless steel. Burner  10  has right burner side  12  and left burner side  15 .  
         [0032]     Right and left burner sides  12  and  15  have right and left outer edges  13  and  16 , respectively. Right and left burner sides  12  and  15  are joined together through the use of several spot welding points along right and left outer edges  13  and  16 , as shown in  FIG. 3 . Although this is the preferred means of joining the burner sides together, other fastening means and methods are contemplated by the present invention. These methods include, but are not limited to, more permanent means and methods, such as with fasteners, by tabs that bend over the outer edges  13  and  16 , or by embosses in the burner sides  12  and  15 , so that no relative motion between burner sides  12  and  15  is possible.  
         [0033]     Referring specifically to  FIG. 4 , right gas inlet ring  14  and left gas inlet ring  17  are formed along the bottom portion of right and left outer edges  13  and  16  respectively. Thus, when right and left burner sides  12  and  15  are connected the two inlet rings form a circle that receives gas input from gas manifold  30 , discussed in further detail below.  
         [0034]     Burner  10  also has mounting bracket tab  11 . During assembly, mounting bracket tab  11  is bent to one side to accommodate mounting bracket  61 , discussed in further detail below.  
         [0035]     Burner  10  also has burner screen face  20  and burner screen frame  21 . Burner screen frame  21  is formed from one continuous sheet of metal, and has center screen support  22  (seen more clearly in  FIG. 5 ), right side securing tab  23 , left side securing tab  24 , a pair of upper securing tabs  25 , a pair of lower securing tabs  26 , and lower and upper support clips  18  and  19 . Thus, burner screen frame  21  is placed on the opening in the body of burner  10  as shown, with burner screen face  20  placed over it. Right side securing tab  23 , left side securing tab  24 , upper securing tabs  25 , and lower securing tabs  26  are then bent over burner screen face  20  to hold it in place. Burner screen face  20  can also be spot welded to center screen support  22  to provide additional support.  
         [0036]     Burner screen  20  and burner screen frame  21  are designed to provide optimal mixing of the combustion products before ignition. The screen and frame design has also proven to be better for flame retention as opposed to traditional cast hole burners and perforated plate components commonly in use.  
         [0037]     Lower and upper support clips  18  and  19  provide additional support to the burner by fitting around right and left burner sides  12  and  15  just above and below the burner face. Although in the shown embodiment the means of attachment is that of a simple pressure fit, other means of connecting lower and upper support clips  18  and  19  to the body of burner  10  are contemplated by the present invention, including more permanent attachment means such as welding.  
         [0038]     Referring to  FIGS. 6 and 7 , burners  10  are connected to gas manifold  30  as shown. Gas manifold  30  has right mounting bracket  32  and left mounting bracket  33 , used to hold gas manifold  30  in place during operation of the shown burner assembly.  
         [0039]     Gas manifold  30  also has one or more gas nozzles  34 . In the shown embodiment, there are five such nozzles; however, the present invention contemplates the use of one or more nozzles, to correspond to the number of burners used. Gas nozzles  34  are aligned along the axis of gas manifold  30  so that they correspond to the opening at the bottom of burner  10  formed by right and left gas inlet rings  14  and  17 . Gas nozzle  34  is then inserted into the opening. Thus, during operation, gas is supplied to gas manifold  30  through gas manifold inlet  35 , and enters burner  10  after passing through gas nozzle  34 . Gas nozzle  34  is connected to gas manifold  30  with a threaded connection; however, other more permanent means and methods of connecting gas nozzle  34  to gas manifold  30  are contemplated by the present invention.  
         [0040]     In the present invention, burners  10  are substantially 90° in-shot burners, which draw in ambient air through the bottom of burner  10  as gas is injected by gas nozzles  34 . This orientation of the burner encourages more thorough mixing of the gas fuel with the ambient air, to allow for more efficient burner operation. Thus, this orientation of the burners achieves a better mixing of gas fuel and air, and ultimately produces a combustion that is more controllable, consistent and efficient than in other burner orientations. In the shown embodiment, the burner face is at a 90° orientation to the opening through which gas enters the burner. This angle can be varied, however, from approximately 70° to approximately 110°.  
         [0041]     The present invention also has a number of single burner mounting boxes  40 , a number of double burner mounting boxes  42 , or a combination thereof. In the shown embodiment, there are two double burner mounting boxes  42  and one single burner mounting box  40 . Single burner mounting box  40  is designed to accommodate one burner  10 , and double burner mounting box  42  is designed to accommodate two burners  10 . In use, the burner mounting box is attached to the side of the frypot, as is shown in  FIGS. 1 and 2 . Top mounting tab  41  is used in a tab and slot mechanism that connects the mounting box to the frypot.  
         [0042]     The present invention also has primary pilot assembly  50  and secondary pilot assembly  52 , which have primary pilot stem  51  and secondary pilot stem  53 , respectively. Primary pilot assembly  50  and secondary pilot assembly  52  can be standard assemblies that are fitted to the burners and mounting boxes. The pilot assemblies can be lit manually, or with the use of an electrical ignition system, which is shown in the diagrams.  
         [0043]     Primary pilot stem  51  is connected directly to an external gas valve. Secondary pilot stem  53  is connected to pilot orifice  36  of gas manifold  30 . In the shown embodiment, secondary pilot stem  53  is connected to pilot orifice  36  with a threaded connection; however, other more permanent means and methods of connecting secondary pilot stem  53  to pilot orifice  36  are contemplated by the present invention.  
         [0044]     Both primary and secondary pilot assemblies  50  and  52  are connected to the frypot with the use of pilot assembly bracket  54 . Pilot assembly bracket  54  has aperture  55 . During assembly, a fastener can be inserted through aperture  55  to connect pilot assembly bracket  54  to the frypot.  
         [0045]     Both primary pilot assembly  50  and secondary pilot assembly  52  split the gas flowing up pilot stems  51  and  53 , respectively, into two directions. In one embodiment of the invention, gas exits from the top end of primary and secondary pilot assemblies  50  and  52 , and is lit by the ignition mechanism. The resulting flame passes on to burners  10  through pilot carryover structures  46 . Double burner mounting boxes  42  have mounting box carryover structures  47  to assist in the lighting of both burners within. Thus, mounting box carryover structure  47  ensures proper flame propagation between adjacent burners within double burner mounting box  42 . This improves the overall ignition and reliability of the fryer by ensuring that both burners within double burner mounting box  42  are lit by the pilot. In a second embodiment of the invention, gas exits from the top end of primary pilot assembly  50 , and is lit by the ignition mechanism. The resulting flame passes on to adjacent burners  10  through pilot carryover structure  46 . Flame now present on the centermost burner  10  passes to the secondary pilot assembly  52  through the corresponding pilot carryover structure  46  to ignite the fuel gas emitting from secondary pilot stem  53 . Flame then passes to the remaining burners  10  through the secondary pilot assembly  52  carryover structure  46 .  
         [0046]     In the shown embodiment, there are two pilot assemblies used. This is advantageous because it provides additional safety in the event that one of the pilots is extinguished during fryer operation. However, the present invention contemplates the use of one or more pilot assemblies.  
         [0047]     Referring to  FIGS. 8, 9 ,  10 , and  11 , when the fryer is in use the burners  10  are held in place by bracket housing  60  and burner mounting bracket  61 . Bracket housing  60  is welded onto the frypot. Mounting bracket  61  has one or more bracket burner notches  62 , corresponding to the number of burners  10  used. Thus (as is shown specifically in  FIG. 10 ), when bracket housing  60  and mounting bracket  61  are placed over the burners  10 , mounting bracket tab  11  of burner  10  is bent to the side. This creates a ridge out of right and left outer edges  13  and  16  for mounting bracket  61  to rest on, through burner mounting notches  62 . Mounting bracket  61  is then fastened to bracket housing  60  with the use of two bracket fasteners  63  on either side of mounting bracket  61 . Thus, bracket housing  60  and mounting bracket  61  hold burners  10  in place while the frypot is in use, and only require two fasteners to complete the assembly.  
         [0048]     Referring specifically to  FIG. 11 , the keyed system that holds burners  10  steady is shown. Single mounting box  40  and double mounting box  42  each have at least one burner interface opening  43 . During operation, the face of burner  10  is placed in burner interface opening  43 . Burner interface opening  43  also has lower mounting notch  44  and upper mounting notch  45 . These notches correspond to lower and upper support clip  18  and  19  of burner  10 , respectively. Thus, when the face of burner  10  is inserted into burner interface opening  43 , lower and upper support clips  18  and  19  are inserted into lower and upper burner notches  44  and  45  respectively, holding burner  10  in place. Mounting bracket  61  is then connected to bracket housing  60  as described above, preventing any significant movement by burners  10 .  
         [0049]     There are several advantages to the design of the single and double burner mounting boxes described above. First, the mounting notches on the burner mounting box face allow for a quick and easy removal and re-installation of the burners. Traditionally, burners in tube fryers are mounted to the frypot with the use of one or more fasteners per burner. These fasteners often take a substantial amount of time to remove. In the present invention, the burners are easily serviced by removing the two fasteners  63  from mounting bracket  61  and removing the bracket. These are the only two fasteners that need to be removed in order to service the burners  10 . Burner  10  is then removed from the mounting box by sliding it out of lower and upper mounting notch  44  and  45 .  
         [0050]     Another advantage to the mounting box design is that it substantially prevents surplus ambient air, in addition to what is already inside the burner body, from being suctioned into the heat exchanger tube. When too much ambient air (which has not been properly mixed with the combustion gas inside the body of burner  10 ) enters the heat exchanger tube, the efficiency of the fryer is decreased because the hot combustion gasses are diluted with relatively cool air. The burner mounting boxes  40  and  42  are attached to the side of the frypot as described above, preventing any introduction of ambient air at that point in the assembly. The face of burner  10  is inserted into mounting box burner opening  43 , lower mounting notch  44 , and upper mounting notch  45  (as described above) so that there is very little space between the face of burner  10  and burner opening  43 . Therefore, very little ambient air enters the heat exchanger tube during operation.  
         [0051]     Referring to  FIGS. 12 and 13 , heat transfer baffle  80  is shown. Heat transfer baffle  80  has one or more baffle openings  81  and baffle fins  82 . In the present embodiment, heat transfer baffle  80  has twelve baffle openings  81  and twelve baffle fins  82 ; however, other baffle opening and fin configurations are contemplated by the present invention. Baffle fins  82  can be bent at a variety of angles and configurations to ensure optimal mixing of the combustion gasses. In the shown embodiment, the front six baffles are bent at a sixty-degree angle, three to the left and three to the right. The rear six baffles are bent at ninety-degree angles, three to the left and three to the right.  
         [0052]     Heat transfer baffle  80  also improves the heat transfer efficiency of the fryer by acting as a source of heat transfer itself. Heat transfer baffle  80  is heated by the combustion gasses during fryer operation and subsequently conducts and radiates heat to the heat exchanger tube.  
         [0053]     Heat transfer baffle  80  also has rear locating tab  83  and front locating tab  84 . During assembly, front and rear locating tabs  84  and  83  are connected to heat exchanger tube  70  to hold heat transfer baffle  80  in place.  
         [0054]     To initialize the deep fat tube fryer of the present disclosure, the operator turns on the fryer heat controls (not shown). If the temperature of the cooking oil medium in frypot  95  is below a required oil set point temperature, the control circuit energizes the primary and secondary pilot assemblies  50  and  52 . Once a sensor in the pilot assemblies measures a pilot flame, the main valve of gas inlet  35  opens and gas then flows from gas inlet  35  into gas manifold  30 . Gas rises up from gas manifold  30 , through gas nozzle  34 , into the body of burner  10 . Gas rising up through the body of burner  10  mixes with atmospheric air and exits ninety degrees out through the burner face. At the burner face, the pilot flame ignites the gas/air fuel mixture. Flame and combustion gasses travel through the heat exchanger tubes  70 , transferring heat to the tubes, heat transfer baffles  80  and subsequently to the cooking oil that surrounds heat exchanger tubes  70  in frypot  95 . Combustion by-products continue to move through heat exchanger tubes  70  and exhaust out through flue  90 . Once the control circuit measures frypot oil temperature within a designed tolerance to the set point temperature, the control circuit shuts off the main valve of gas inlet  35 , until the frypot oil temperature drops below the required set point and the burner cycle begins again.  
         [0055]     While several embodiments and features of the present disclosure are discussed above, it is to be clearly understood that the same are susceptible to numerous changes apparent to one skilled in the art. The fryer of the present disclosure, therefore, should not be limited to specific embodiments shown and described, but should also include all changes and modifications which come within the scope of the appended claims.