Abstract:
A stand alone venting apparatus for an enclosed space that converts open door and closed door emissions of a steam and hot air oven into cooler air and condensate, the apparatus comprising an expansion chamber, a condensing chamber and a chilling chamber. A capture hood is provided for capturing the open door emissions. An emissions inlet is provided for capturing the closed door emissions. The condensing chamber includes condensing tubes with each tube containing an interior and an exterior. The open door emissions are directed over the exterior of the condensing tubes and the closed door emissions are directed within the interior of the condensing tubes. The expansion chamber and chilling chambers work with the condensing chamber to further cool and condense the emissions. All emissions may be re-circulated back into the enclosed space without requiring ductwork to vent outside the enclosed space.

Description:
RELATED APPLICATIONS 
     This application claims the benefit of priority of U.S. Provisional Patent Application No. 61/992,839, filed May 13, 2014, which is herein incorporated by reference. 
    
    
     FIELD 
     This patent application generally relates to an apparatus for converting hot air and steam emissions into cooler air and condensate. More specifically it relates to a stand alone venting apparatus including an expansion chamber, a condensing chamber and a chilling chamber; the apparatus is capable of treating emissions from multiple exhaust outlets. 
     BACKGROUND 
     In commercial foodservice operations, supermarkets and other confined-space food preparation environments; food cooking and heating equipment can create undesirable air conditions when not properly vented. Untreated exhaust emissions from the equipment can be unacceptably warm, include smoke, grease and particulates that are unpleasant and unhealthy. In order to insure a healthy and safe environment for confined spaces, regulatory agencies monitor the installation of equipment and require that emissions generated from heating and cooking equipment be treated to acceptable levels before exhausting. 
     To ensure air quality, food exhaust emissions are usually treated with ventilation boxes (vents or hoods) that are suspended over all equipment and the emissions removed by ductwork to the exterior of the building. These ventilation systems are very expensive. They require extensive ducting and penetration through building structures. Grease and particles may buildup on the interior of the ductwork, requiring further expensive cleaning, which if not done adequately on a regular basis may result in fires. 
     Recently there have been developments in localized appliance venting whereby exhaust emissions are adequately treated and re-circulated back within a building structure. One such example is described in U.S. Pat. No. 8,522,770 to Colburn et. al. These appliances require that smoke, particulates, odor and grease be adequately removed from the air to a suitable level in order to return the air back into the building in a condition where the air is safe, healthy and pleasant. These appliances have saved a great deal of money and inconvenience compared to earlier solutions; however, they only work with certain types of food treatment equipment. 
     The use of steam cooking equipment utilizing both hot air and steam (combination ovens) has seen a dramatic increase in the last decade. These steam cooking appliances are versatile, have reduced processing times and produce healthy food. They are generally larger than standard ovens, but they can also exist as countertop equipment. The appliances are often used in locations other than central kitchens due to their flexibility and stand-alone functionality. They are also often used in multiple locations throughout a facility. This presents a challenge when trying to implement traditional venting that has ductwork to the outside of the building. The installation of that ductwork can be prohibitively expensive when trying to install the ducted venting at remote and multiple locations throughout a facility. In addition to emissions of grease, volatile oils, water vapor, odor, heat and sometimes smoke that is seen in a traditional oven, these appliances also emit a large amount of steam that requires treating and a drain for condensate. The steam must be condensed to water when vented from the oven and the condensed water must be cooled to less than 82° C. before reaching drain piping. Grease, smoke and odor from the air and steam must be removed before returning air to the enclosed environment. A further complication for these combination ovens is that the steam, hot air and particulates vent from multiple outlets; a sealed exhaust outlet connected to the oven and a different location when the door is opened. A venting solution must adequately capture and treat emissions from both of these exhaust locations. 
     This present patent application provides for an apparatus that converts hot air and steam emissions into cooler air and condensate. The apparatus is also capable of treating emissions from multiple exhaust sources. 
     SUMMARY 
     One aspect of the present patent application is directed to an apparatus for converting hot air and steam emissions into cooler air and condensate. The apparatus comprises a housing including an expansion chamber. An emissions inlet is provided to deliver the hot air and steam to the expansion chamber. A condensing chamber is located within the housing and receives hot air and steam from the expansion chamber. A chilling chamber is located within the housing and receives the hot air and steam from the condensing chamber. A condenser outlet exits the chilling chamber to exhaust cooler air and condensate. 
     Another aspect of the present patent application is directed to an apparatus for treating open door and closed door emissions of a steam and hot air oven. The apparatus comprises a housing integrated with a capture hood, the capture hood for capturing the open door emissions of the steam and hot air oven. An emissions inlet is integrated with the housing, the emissions inlet for capturing the closed door emissions of the steam and hot air oven. The apparatus also comprises a condensing chamber within the housing; the condensing chamber includes condensing tubes with each tube containing an interior and an exterior. The open door emissions are directed over the exterior of the condensing tubes and the closed door emissions are directed within the interior of the condensing tubes. 
     Yet another aspect of the present patent application is directed to an apparatus for controlling exit temperature of condensate and air. The apparatus comprises a chilling chamber for holding condensate, steam and air. The chilling chamber has a chilling surface for chilling air and a bottom surface for collecting the condensate. A condensate outlet exits the chilling chamber at the bottom surface. A thermoelectric device is in thermal contact with the chilling surface. The thermoelectric device is for removing heat from the chilling surface. The apparatus further comprises a temperature sensor and a switch. The switch receives temperature information from the temperature sensor. The switch uses the temperature sensed by the temperature sensor to turn on and off the thermoelectric device to keep the condensate temperature below a specified value. 
     Still yet another aspect of the present patent application is directed to a condensate switching device. The condensate switching device comprises a condensate reservoir for holding a quantity of condensate. The condensate reservoir has a vertical wall with a drain opening located at a vertical height. The vertical height determines a set level of condensate contacting a condensate temperature sensor. The condensate temperature sensor is integrated to sense condensate temperature. The condensate temperature sensor is activated when condensate touches the temperature sensor. A switch is in communication with the condensate temperature sensor. The switch has an ON high-temperature state and an OFF low-temperature state, the temperature of the condensate activates the switch. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       The foregoing and other aspects and advantages presented in this patent application will be apparent from the following detailed description, as illustrated in the accompanying drawings, in which: 
         FIG. 1  is a front-side, perspective view of a venting apparatus according to the present invention, the apparatus integrated with a combination steam and hot air oven; 
         FIG. 2  is a back-side, perspective view of the integrated venting apparatus in  FIG. 1 ; 
         FIG. 3  is a sectional, view of the integrated venting apparatus in  FIG. 2  along line  3 - 3 ; 
         FIG. 4  is a top-side, perspective view of the venting apparatus in  FIG. 1 ; 
         FIG. 5  is a top-side, perspective view of the venting apparatus in  FIG. 4  with the top of the housing removed; 
         FIG. 6  is a top view of the venting apparatus in  FIG. 4  looking into the apparatus with the top of the housing removed; 
         FIG. 7  is a sectional view through a condensing tube of the condensing chamber, the sectional view along line  7 - 7  of  FIG. 4 ; 
         FIG. 8  is a sectional view through the chilling chamber, the sectional view along line  8 - 8  of  FIG. 4 ; 
         FIG. 9  is the same top view of the venting apparatus in  FIG. 6  with emissions flow through the apparatus depicted for emissions captured by both the capture hood and emissions inlet; and 
         FIG. 10  is side-schematic, sectional view of one embodiment of a condensate switching device. 
     
    
    
     DETAILED DESCRIPTION 
     Apparatus  20  for treating open door emissions  22  and closed door emissions  24  from a combination hot air and steam oven  26  is illustrated in  FIGS. 1-10 . Apparatus  20  comprises a housing  28 . Housing  28  is generally rectangular in shape having a top, bottom, front, back and sides. A capture hood  30  is usually integrated with housing  28  at the front. Capture hood  30  is located to capture open door emissions  22  from oven  26  when door  32  of the oven is opened. Within housing  28  are contained three chambers; an expansion chamber  34 , a condensing chamber  36  and a chilling chamber  38 . A sealed exhaust outlet  40  from oven  26  delivers hot air and steam emissions to expansion chamber  34  through emissions inlet  42 . When the oven door  32  is closed, these emissions (closed door emissions  24 ) are pressurized. The pressure-differential forces these emissions to move through expansion chamber  34  where they expand, cool and start to condense. Condensing chamber  36  receives the cooler hot air and steam emissions internally into condensing tubes  44 . In condensing chamber  36 , most of the emissions are condensed. The now still cooler hot air, steam and condensate  46  are delivered to chilling chamber  38 . In chilling chamber  38  any remaining steam is condensed and the condensate temperature lowered to an acceptable level for exhausting to a drain  48 . Condensate  46  flows through condensate outlet  50  that exits chilling chamber  38 . In parallel the treatment of open door emissions  22  occurs by having the open door emissions drawn into capture hood  30  by fan  52  through hood filter  90 . These open door emissions  22  flow through condensing chamber  36  where they cool and condense around condensing tubes  44  and cooling fins  62 . Any condensate  46  that forms flows into chilling chamber  38  to be further chilled and drained, while the cooled air exits the back of apparatus  20 . 
     The details of expansion chamber  34  are shown in  FIGS. 5, 6 and 9 . Expansion chamber  34  includes a baffle  54 . Baffle  54  has a plurality of baffle surface  56  that create a lengthened path for the hot air and steam (closed door emissions  24 ) to travel as these emissions pass through expansion chamber  34 . In one embodiment baffle surfaces  56  are position at right angles to each other to create a sinuous lengthened path. The hot air and steam enter through emissions inlet  42  and pass through expansion filter  58 . Expansion filter  58  removes any grease and other particulates from the emissions. Expansion filter  58  can be removed, cleaned and replaced when contaminated. Once through expansion filter  58 , the hot air and steam emissions then travel around each baffle extension  60 . While traveling around each baffle extension  60 , the pressurized emissions expand and cool. The lengthened back and forth path also provides many opportunities for the cooling gas and particles to condense on baffle  54 . The now cooler and partially condensed hot air and steam emissions then exit expansion chamber  34  and enter condensing tubes  44  of condensing chamber  36 . 
     The details of condensing chamber  36  are shown in  FIGS. 5-7 and 9 . Condensing chamber  36  contains at least one, but preferably a plurality of condensing tubes  44  that run from expansion chamber  34  to chilling chamber  38 . Condensing tubes  44  preferably are at a decline from expansion chamber  34  to chilling chamber  38  to facilitate draining of condensate  46  into the chilling chamber. Condensing tubes  44  each have a plurality of cooling fins  62  extending from the outer condensing walls of the condensing tubes. Both condensing tubes  44  and fins  62  are made from high thermal conductivity materials such as metals. Steam and hot air emissions entering each condensing tube  44  are cooled as these emissions pass through the condensing tube. Fan  52  is constantly pulling room temperature air in through capture hood  30  from outside housing  28  to inside the housing and over cooling fins  62 , this cooler ambient air is directed externally over condensing tubes  44  to remove excess heat from the condensing tubes to facilitate condensing within the tubes. The still cooler emissions, steam and condensate then flow into chilling chamber  38 . 
     The details of chilling chamber  38  are shown in  FIGS. 5, 6, 8 and 9 . Chilling chamber  38  is a generally an open chamber with one or more chilling surface  64  (steam chilling surface  64   a  and condensate chilling surface  64   b ). Chilling surface  64  may be any of the surfaces within chilling chamber  38 . One or more thermoelectric devices  66  are mounted in contact with a chilling surface  64  to remove heat from the chilling surface. For example, thermoelectric device  66  may be Model No. TE-127-1.0-1.3 from TE Technology, Inc. Chilling chamber  38  includes at least one temperature sensor  68 . Temperature sensor  68  monitors the temperature of at least one from the group consisting of a chilling surface of the chilling chamber (surface temperature sensor  70 ), gases and condensate  46  within the chilling chamber (gas temperature sensor  71 ), and gases and condensate exiting the chilling chamber (condensate temperature sensor  72 ). Chilling chamber  38  further includes a switch  74 . Switch  74  may itself react directly to the chilling surface temperature within chilling chamber  38  (i.e., a bimetallic snap switch) or the switch may receive temperature information from any of the temperature sensors  68 . Switch  74  activates thermoelectric device  66   a  to chill steam chilling surface  64   a  when the chilling surface is above a set temperature. For example, setting switch  74  to activate steam thermoelectric device  66   a  to be ON and removing heat if the temperature at steam chilling surface  64   a  is at 95° C. will ensure that no steam will exit chilling chamber  38 . 95° C. is only used as an example; other temperatures could be used as a set point to keep the chilling surface below 100° C. All condensate  46  and cooled air will exit chilling chamber  38  through condensate outlet  50  and into drain  48 . 
     In one embodiment a condensate switching device  76  may be integrated between condensate outlet  50  and drain  48 ,  FIG. 10 . Condensate switching device  76  includes a condensate reservoir  78  in line with said condensate outlet  50  and having a vertical wall  80  with a drain opening  82  located at a vertical height  84 . Vertical height  84  determines a set level of condensate  46  within condensate reservoir  78 . Condensate temperature sensor  72  is integrated to sense condensate temperature. Switch  74 , in communication with condensate temperature sensor  72 , is activated to ON for a high-temperature state and OFF for a low-temperature state. The temperature of condensate  46  in condensate reservoir  78  causes switch  74  to turn on and off thermoelectric device(s)  66   b  to insure that condensate temperature is below a specified temperature and does not exit into drain  48  above that specified temperature.
         In one embodiment, temperature sensor  68  is two temperature sensors working together. The two temperatures sensors are surface temperature sensor  70  to monitor temperature of chilling surface  64  and condensate temperature sensor  72  to monitor temperature of the condensate. Together the two temperature sensors monitor if steam is present in chilling chamber  38  and the exit temperature of condensate  46  that is exiting chilling chamber  38 . Thermoelectric devices  66  are turned on and off independently by surface temperature sensor  70  or condensate temperature  72  sensor to ensure that no steam exits chilling chamber  38  and that the condensate  46  exiting the chilling chamber is less than a set temperature.       

     Drainage gap  86  exists on the bottom of housing  28  between expansion chamber  34 , condensing chamber  36  and chilling chamber  38 ,  FIG. 7 . Drainage gap  86  allows for all condensate  46  generated in any three of the chambers to flow to chilling chamber  38  and eventually exit through condensate outlet  50 . 
     Capture hood  30  serves two purposes. When door  32  of oven  26  is closed, capture hood  30  allows fan  52  to draw in room temperature air across cooling fins  62  to cool condensing tubes  44 . When door  32  is open, capture hood  30  allows fan  52  to draw in open door emissions  24  across cooling fins  62  where they can be cooled. A capture hood filter  90  is provided internal to capture hood  30 . Capture hood filter  90  is located after capture hood  30  and prior to condensing chamber  36 . Capture hood filter  90  removes any grease and other particulates from the emissions. Capture hood filter  90  can be removed, cleaned and replaced when contaminated. 
     General operation of apparatus  20  is as follows. When door  32  is closed, closed door emissions  24  (steam and hot air emissions) build up pressure within oven  26 . These closed door emissions are force out through sealed exhaust outlet  40  and into emissions inlet  42 . As closed door emissions  24  enter expansion chamber  34 , they first pass through expansion filter  58  where grease and other particulates are captured. The closed door emissions  24  then expand and cool as they follow a long path around baffle  54 . Cooling allows water vapor to condense. The condensation is facilitated by coming in contact with the many surfaces of baffle  54 . Any condensate  46  generated drops to the bottom of the chamber and flows through drainage gap  86  towards condensate outlet  50 . The now cooler closed door emissions  24  enter condensing tubes  44  of condensing chamber  36 . Fan  52  pulls room temperature air over cooling fins  62  to continuously cool condensing tubes  44 . Within tubes  44  closed door emissions  24  are further cooled and more condensate  46  is condensed from the emissions. The still cooler closed door emissions  24  and condensate  46  flow out condensing tubes  44  and into chilling chamber  38 . Once is chilling chamber  38 , the temperature of the air and condensate  46  are measured. If the temperature of the air shows that the air may still contain steam, steam thermoelectric device(s)  66   a  are activated to chill steam chilling surface  64   a . Also if the temperature of condensate  46  is above an acceptable temperature (usually 82° C.), then condensate thermoelectric device(s)  66   b  are activated to chill condensate chilling surface  64   b  and further cool the condensate. Steam chilling surface  64   a  and condensate chilling surface  64   b  are on opposite sides of the housing walls. All closed door emissions  24  then exit condensate outlet  50  and into drain  48  as either cool air or cool condensate. 
     When door  32  is open, open door emissions  22  (steam and hot air emissions) exit oven  26  and are collected by capture hood  30 . Fan  52  draws in open door emissions  22 . Open door emissions  22  first pass through capture hood filter  90  where grease and other particulates are captured. These open door emissions  22  flow through condensing chamber  36  around cooling fins  62  where they cool and condense. Any condensate  46  that forms then drops to the bottom and flows into chilling chamber  38  through drainage gap  86  to be further chilled and drained. The remaining air passes out the back of apparatus  20 . 
     While several embodiments of the invention, together with modifications thereof, have been described in detail herein and illustrated in the accompanying drawings, it will be evident that various further modifications are possible without departing from the scope of the invention. The scope of the claims should not be limited by the preferred embodiments set forth in the examples, but should be given the broadest interpretation consistent with the description as a whole.