Abstract:
A water-based scrubber is used to remove ethanol and other VOCs from the exhaust of a commercial bakery oven, particularly a tunnel oven. The exhaust from the oven is forced through the water of the scrubber so that ethanol and other VOCs become dissolved in the water. The water, including the dissolved ethanol and VOCs, is periodically removed from the scrubber, treated and disposed of through a convention sewer or drain.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     The present invention relates a water-based scrubber for removing ethanol and other VOCs (volatile organic compounds) from the exhaust of a commercial bakery oven.  
         [0003]     2. Description of the Prior Art  
         [0004]     It is well-known in the prior art that the exhaust from commercial bakery ovens includes ethanol and other VOCs. In particular, the ethanol is formed by yeasts acting upon sugars and starches at the increased temperatures involved in the baking process. This ethanol, along with other VOCs, is considered to be a significant source of air pollution and, therefore, the subject of substantial state and federal regulation. Additionally, this exhaust typically includes particulate (bread crumbs), grease, oil and a high level of moisture.  
         [0005]     Moreover, any solution to this problem cannot substantially alter the airflow of the bakery oven, which is critical to the finished product.  
         [0006]     A common solution is an oxidizer which creates a flame from an independent fuel source in order to burn the ethanol vapors. Oxidizers, however, are extremely expensive, perhaps as much as a million dollars, and require substantial maintenance and operating expenses. However, as many commercial bakeries, particularly smaller commercial bakeries, are typically low-profit margin, thinly capitalized operations, such a solution is not practical.  
       OBJECTS AND SUMMARY OF THE INVENTION  
       [0007]     It is therefore an object of the present invention to provide a method and apparatus for removing ethanol and other VOCs from the exhaust of a commercial bakery oven, such as a tunnel oven, thereby meeting environmental regulations.  
         [0008]     It is therefore a further object of the present invention to provide a method and apparatus for removing ethanol and other VOCs from the exhaust of a commercial bakery oven, such as a tunnel oven, without adding any further contaminants into the air.  
         [0009]     It is therefore a still further object of the present invention to provide a method and apparatus for removing ethanol and other VOCs from the exhaust of a commercial bakery oven, such as a tunnel oven, without causing any substantial odors.  
         [0010]     It is therefore a still further object of the present invention to provide a method and apparatus for removing ethanol and other VOCs from the exhaust of a commercial bakery oven, such as a tunnel oven, without substantially changing the airflow balance of the oven.  
         [0011]     It is therefore a still further object of the present invention to provide a method and apparatus for achieving the above objects without being excessively expensive or requiring excessive maintenance and operating expenses.  
         [0012]     These and other objects are attained by providing a scrubber which includes a tank of water and a blower which urges the exhaust gas through the water. The scrubber passes the exhaust gas of the commercial bakery oven, such as a tunnel oven, through a water bath, which causes the ethanol to separate from the exhaust and mix with the water circulated in the scrubber, with the scrubbed exhaust being released into the atmosphere. The amount of water in the scrubber is maintained and a constant level by a floating device and is refreshed by an automatic valve. The water which is removed from the scrubber is directed to a water treatment room where it is prepared and treated as waste water before being released into a sewer system. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0013]     Further objects and advantages will become apparent from the following description and claims, and from the accompanying drawings, wherein:  
         [0014]      FIG. 1  is a perspective view, partially in phantom, of the scrubber of the present invention.  
         [0015]      FIG. 2  is a first cross-sectional view of the scrubber of the present invention.  
         [0016]      FIG. 3  is a second cross-sectional view of the scrubber of the present invention.  
         [0017]      FIG. 4  is a cross-sectional view of the expansion tank baffle of the scrubber of the present invention.  
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0018]     Referring now to the drawings in detail—wherein like numerals indicate like elements throughout the several views, one sees that  FIGS. 1-3  are various views of the scrubber  10  of the present invention. Scrubber  10  includes main tank  12  which is typically made from stainless steel (typically stainless steel type 304) and may have a height of 34 inches, a length of 54 inches and a width of 36 inches. However, those skilled in the art will recognize a range of equivalents for this material and dimensions, as well as any other materials and dimensions given herein, after review of the present disclosure.  
         [0019]     Main tank  12  includes an inlet water line  14  and a flow device  16  to maintain the water level in main tank  12  of scrubber  10 . The level of the water is further controlled or limited by the level of the opening  18  of overflow pipe  20  (typically formed of PVC pipe). Likewise, oil skimmer  22 , shaped as an inverted cone, is attached by pipe  24  to overflow pipe  20  and skims oil from the surface of the water, and limits the level of the water in main tank  12 . Lower drain pipe  26  opens into the floor  28  of main tank  12  and permits the substantially complete discharging of water from main tank  12  as controlled by discharge water valve  30  controlled, in turn, by timer  32 . Lower drain pipe  26  discharges water to treatment module (not shown) which, in turn, typically discharges the treated water into a conventional sewer or drain (not shown).  
         [0020]     Main tank baffle plates  34 ,  36  are formed vertically in main tank  12  between overflow pipe  20  and oil skimmer  22 , and are typically formed of 18 gauge stainless steel. Apertures  38  are formed in main tank baffle plates  34 ,  36  to allow the free flow of liquid therethrough.  
         [0021]     Expansion tank  40  is formed above main tank  12 . Expansion tank  40  is typically formed of stainless steel (again, typically stainless steel 304) and may have sides of 32 inches and a height of 36 inches. Expansion tank baffle  42  is formed downwardly adjacent from the upper edge  44  of expansion tank  34 . As shown in  FIG. 4 , expansion tank baffle  42  has a lower row of upwardly facing V-shaped elements  44  with interstices  46  therebetween and a upper row of downwardly facing V-shaped elements  48  with interstices  50  therebetween. The resulting construction causes the exhaust rising through an opening (not shown) in main tank  12  to expansion tank  40  to pass through interstices  46  of the lower row of upwardly facing V-shaped elements  44 , to pass diagonally downwardly through the space formed between upwardly facing V-shaped elements  44  and downwardly facing V-shaped elements  48 , and then to pass through interstices  50 . This inhibits the passing of water through expansion tank baffle  42  as the exhaust rises into conical exhaust pipe  56 .  
         [0022]     Conical exhaust pipe  56 , with an open top and bottom, is typically formed of stainless steel (again, typically stainless steel 304) and may have a lower diameter of  29  inches, an upper diameter of 10 inches and a height of 21½ inches.  
         [0023]     Main tank  12  further includes horizontal blower outlet pipe  58  which passes through the wall thereof and engages diagonal blower outlet pipe  60  which extends below the water level (that is, to a level lower than opening  18  of overflow pipe  20 ). Diagonal blower outlet pipe  60  includes several apertures  61  around the periphery thereof, below the water level. Apertures  61  are typically one inch in diameter and serve to stabilize scrubber  10 , particularly at high volumes of exhaust throughput. Horizontal blower outlet pipe  58  receives the outlet of air blower  62 . Air blower  62  is typically a radial blade belt drive booster in the 3 to 5 horsepower range, operating at 3450 rpm and having a throughput of 515 to 1780 cubic feet per minute. Air blower  62  receives the exhaust from a commercial bakery through oven exhaust stack  64  and blows the exhaust through outlet pipes  58 ,  60  so as to pass through the water. This causes at least a portion of the ethanol and other VOCs to dissolve in the water and be removed from the exhaust. The exhaust thereafter passes upwardly from main tank  12 , through expansion tank  40  and out of conical exhaust pipe  56 .  
         [0024]     In order to operate scrubber  10 , water is inlet though inlet water line  14  so as to rise to the level of opening  18  of overflow pipe  20 . Exhaust from the commercial bakery is thereafter urged through the water as previously described, so as to remove a substantial portion of the ethanol and other VOCs from the exhaust, which ultimately passes out of conical exhaust pipe  56 . Periodically, timer  32  activates discharge water valve  30  to allow the water to drain through lower drain pipe  36 . The water is treated by directed to a water treatment room where it is prepared and treated as waste water before being released into a sewer system.  
         [0025]     Thus the several aforementioned objects and advantages are most effectively attained. Although preferred embodiments of the invention have been disclosed and described in detail herein, it should be understood that this invention is in no sense limited thereby and its scope is to be determined by that of the appended claims.