Fume incinerator
[ 1 Apr. 29, 1975 limited States Patent 1191 Shaw 1 1 FUME HNCINERATOR Primary Examiner loseph Scovronek [76] Assistant Examiner-Arnold Turk Inventor: Alexander Shaw, Box 45, Braddock Heights, Md. 21714 Attorney, Agent, or F irmLarson, Taylor &amp; Hinds r m r: e n r u b n. m f a n 3 Tee .m AB r mp m we r 0 t a r E .m C .m e m f BA 2 7 9 1 ml 24 3 @9 S2 0 N .ml 0.. MP FA H 1 22 burning the combustibles in the exhaust from a restau- [52] U.S. 23/277WC; 110/8 A; 423/210 ram and the mm A primary burning chamber is [51] Int Cl 7/06 F23C 9/04 vided having a semicircular baffle therein to cause the [58] Field of Search........... 110/8 A, 8 R; 23/277 C;  
 fumes to follow a circular pattern while being subjected to the heat of the primary burner. The fumes then pass to a secondary burning chamber where a References Cned semicircular baffle creates a circular flow path while UNITED STATES PATENTS the remaining combustibles in the exhaust gasses are 110/8 A burned prior to the gas being passed out through the 110/8 A exhaust stack. Total retention time of the gas within 110/3 A X the after burner unit is 0.5 second.  
 3,310,009 Jacobs 3,552,332 Mattenley 3,730,112 Hutchinson.....  
 7 Claims, 3 Drawing Figures FUME INCINERATOR The present invention relates to a fume incinerator and more particularly to an afterburner unit which is designed to completely burn all of the combustibles within the exhaust fumes from a restaurant.  
  Many states require that an afterburner be provided for burning the combustibles in the exhaust stack from a charcoal grill. Heretofore such afterburner have been too expensive to operate or do not provide sufficient residence time of the gas within the unit to completely incinerate all of the combustibles. In order to provide sufficient residence time within the unit to burn up the combustibles it is necessary that baffles be provided within the unit to redirect or slow the gas flow. However. prior art baffling arrangements have generally caused the gas to be held back so that the necessary flow through the unit of approximately 2500 cfm cannot be sustained.  
  According to the present invention there is provided an afterburner unit for exhaust fumes which is simple in construction and economical to operate and yet which provides sufficient residence time of the gas within the unit to incinerate all of the combustibles while maintaining the necessary gas flow through the unit. The unit is divided into a primary and secondary combustion chamber with each chamber being provided with a semicircular baffle plate extending entirely across the combustion chamber and having a cut out in a portion of the baffle at one side thereof to permit the gas to flow through the baffle after it has been circulated within the combustion chamber for a sufficient period of time to burn the combustibles within the exhaust fumes.  
  Further, according to the present invention there are provided separate burner elements for the primary and secondary combustion chambers. The unit is so constructed that the primary burner is first ignited to heat the primary combustion chamber to approximately 600F after which the primary chamber burner is cut off and the secondary chamber burner is ignited to heat up the secondary combustion chamber to approximately the same temperature. The unit is sufficiently insulated that these chambers will lose approximately 100F within approximately one hour and at such time the primary burner will again ignite to repeat the cycle. Thus, a minimum amount of fuel is utilized for the intermittently operating burners and both burners are not ignited simultaneously. By virtue of this construction the gas consumption by reason of operation of the afterburners is never sufficiently high to interfere with the other gas requirements of the restaurant.  
  An object of the present invention is to provide a fume incinerator for a restaurant or the like which is simple in construction and which maintains adequate gas flow through the unit while permitting sufficient residence time to burn the combustibles.  
  Another object of the present invention is to provide an afterburner for exhaust fumes wherein primary and secondary combustion chambers are provided with semicircular baffles which cause the exhaust gases to pass in a circular pattern before passing through the outlet from the combustion chamber.  
  Still another object of the present invention is to provide an afterburner unit having primary and secondary combustion chambers with separate burners in each chamber wherein the burners are intermittently and sequentially operated.  
  Other objects and many of the attendant advantages of the present invention will become more readily apparent from consideration of the following detailed specification in connection with the accompanying drawings wherein:  
  FIG. I is a side elevational view of an afterburner unit according to the present invention,  
  FIG. 2 is a plan view in section through the unit along the line 2-2 of FIG. I and FIG. 3 is an elevational front view of one of the baffle plates.  
  Referring now more specifically to the drawings wherein like numerals indicate like parts throughout the several views there is shown in FIG. 1 a generally rectangular shaped housing structure 1 which contains primary and secondary combustion chambers and is adapted to be used as an afterburner for exhaust fumes. This housing structure includes bottom, top, end and side walls and the inlet to the unit is through a central opening in the end wall 2. The inlet to the unit is shown more clearly in FIG. 2 at 3. There is provided an exhaust outlet from the unit in the top wall as shown at 4.  
  As more clearly seen in FIG. 2 the walls of the unit are provided with a refractory lining 5 and substantial insulation between this refractory lining and the outer walls as shown at 6. The insulation may be mineral rock and the refractory lining may be of fire brick or asbestos. The interior of the unit is divided by a central partition 7 which may be of stainless steel. Partition 7 extends from one side wall and the top and bottom walls across the central portion of the unit to a point spaced from the other end wall. Substantially midway along the length of this partition is a semicircular stainless steel baffle plate 8 on one side of the partition and a stainless steel baffle plate 9 on the other side of the partition. Baffle plates 8 and 9 are identical in size and shape and extend across the full width of the respective chamber in which each baffle plate is located. As shown in FIG. 3 the baffle plate 8 has a generally rectangular shaped cut out portion 10 adjacent the outer side thereof and this opening is covered with a mesh screen 11. The baffle plate 9 has a similar cut out and screen.  
  The unit is provided with a primary burner shown generally at 12 and a secondary burner 13. Each of these burners may be gas fired and capable of supplying approximately 200,000 BTUs per hour. The flames from the burner 12 are generally directed towards the baffle plate 8 and the flames from the burner 13 are directed towards the baffle plate 9.  
  The device operates in the following manner. The exhaust stack from the charcoal grill of a restaurant is connected to the inlet 3 so that the gases which are blown out are fed into the afterburner unit toward the baffle plate 8. The primary burner 12 is ignited to heat the primary combustion chamber including the baffle plate 8 and the partition wall 7 to a temperature of approximately 600F. At this point the primary burner is shut off and the secondary burner 13 is ignited to heat the secondary combustion chamber including the baffle plate 9 and partition wall 7 to approximately 600F. The afterburner unit is then ready for operation and gases passing into the primary combustion chamber are caused to move in a generally circular path by reason of the curvature of the baffle plate 8. Particles hitting the baffle plate 8 or the mesh screen 11 are immediately burned and all of the combustibles in the gas are burned due to the high heat within the primary combustion chamber. The rapidly moving gases then pass through the opening in baffle plate 8 and move to the the secondary combustion chamber where again the gasses are subjected to motion in a circular path by reason of the curvature of the baffle plate 9. Any gas combustibles which were not burned within the primary combustion chamber are burned in this secondary chamber before the gases pass outwardly through the opening in baffle plate 9 to the exhaust stack. The fan blows the gases through the chamber at approximately, 2,500 cubic feet per minute and for an afterburnersize of approximately 6 feet in length, 5 feet in width and 4 feet in height it has been found that the residence time of the gas within the afterburner is approximately .5 seconds with a one foot diameter inlet opening. The size of the openings in the baffle plates is important in order to maintain the required gas flow 7 through the unit. In the unit of the specific dimensions described hereinbefore cut out openings in the baffle plates of a 14 inch width and 18 inch height have been found to permit the required gas flow through the unit while maintaining sufficient residence time to burn the combustibles.  
  Due to the highly insulated characteristics of the afterburners unit the temperature drop within the primary and secondary combustion chambers is relatively small. It has been found that during normal operating conditions approximately 1 hour of operation is required&#39;before the temperature within the primary combustion chamber drops to approximately 500F. When this occurs the primary burner 12 reignites to reheat this primary combustion chamber to 600F and when the primary burner cuts off the secondary burner is ignited to bring the secondary combustion chamber to Obviously many modifications and variations of the present invention are possible in light of &#39;the above teachings.  
 What is claimed as new and desired to be secured by Letters Patent is:  
 so as to block the fluid path in each said combustion chamber thereby directing the gases therein to move in a generally circular path in cross section, means for permitting the gases to flow past each said baffle, and primary and secondary burners respectively mounted in said primary and secondary combustion chambers.  
  2. A fume incinerator according to claim 1 wherein said housing includes a central partition, said primary combustion chamber being disposed on one said of said partition and said secondary combustion chamber being disposed on the opposite side of said partition.  
  3. A fume incinerator according to claim I wherein said primary and secondary burners are mounted in the walls of said primary and secondary combustion chambers so as to direct flame therefrom respectively towards said baffles.  
  4. A fume incinerator according to claim 1 wherein each of said baffles includes an opening disposed along a side edge thereof whereby gases passing through said incinerator pass through said opening.  
  5. A fume incinerator according to claim 4 including a wire screen disposed over each opening in said baffles.  
  6. A fume incinerator for oxidizing combustibles within exhaust gases comprising a housing, a central partition mounted in said housing thereby dividing said housing into a first and second combustion chamber, one end of said partition being spaced from a first end wall of said housing to provide fluid communication between said first and second combustion chambers, a first and second semicircular baffle plate disposed on each side of said central partition respectively in said first and second combustion chambers, each baffle plate having a peripheral opening therein, each of said openings being covered by a wire screen, primary and secondary burners mounted in the walls of said housing and directing flame towards said baffle plates and said central partition, an inlet opening in the other end wall of said housing in communication with said first combustion chamber on the upstream side of said first baffle plate, and an outlet in the top wall of said housing in communication with said second combustion chamber on the downstream side of said second baffle plate whereby exhaust gases passing into said inlet are caused to move in a circular path within the primary and secondary combustion chambers by the semicircular baffle plates.  
 7. A fume incinerator according to claim 6 wherein the walls of said housing have a refractory lining.