Afterburner system and process

In a method for the operation of a fireplace located within a structure and adapted to provide heat within said structure, the steps comprising:

• (a) burning a fuel within a primary combustion chamber located within said structure to generate gaseous products of combustion including water, carbon dioxide, carbon monoxide, oxygen and entrained particulate material;
• (b) withdrawing said combustion products from said primary combustion chamber through a confined flue passageway extending upwardly from the primary combustion chamber to the exterior of said structure;
• (c) interrupting the vertical flow of said combustion products within said flue passageway to cause said combustion products to follow a tortuous path in which said entrained particulate material within said gaseous combustion products is separated from said gaseous combustion products and thereafter flowing said combustion products through a secondary afterburner section of said flue passageway having a heating bank comprising a plurality of heating elements therein;
• (d) sensing the temperature of said combustion products at a first location below said afterburner section and a second location located above said heating bank;
• (e) activating said heating elements when the temperature at said first location reaches a specified value in excess of ambient temperature conditions;
• (f) heating said combustion products by said temperature heating elements to a temperature sufficient to convert carbon monoxide in said combustion products to carbon dioxide;
• (g) in response to the temperature at the second location reaching a specified value above that required for the conversion of carbon monoxide to carbon dioxide, deenergizing at least some of heating elements.

In a secondary afterburner for reducing the pollutant level of flue gas resulting from the operation of a primary combustion unit such as a fireplace or the like, the combination comprising:

• (a) a combustion unit enclosure having an interior passageway therein adapted to be inserted into the flue passage of a chimney structure and having an inlet and an outlet;
• (b) a heating bank comprising a plurality of heating elements disposed at longitudinally spaced positions along said interior and located in an upper portion of said unit;
• (c) a baffle section in said flow passage located below said bank of heating elements and having a deflecting member extending transversely across said flue passage to intersect the flow of combustion products from the inlet of said section and prevent direct flow of such products to said heating elements;
• (d) said heating elements being arranged in subsets of two or more heating elements, each subset being connected to an electrical contactor whereby said subsets of heating elements may be individually activated;
• (e) a control system for activating said heating elements;
• (f) a temperature sensor in said unit above said heating elements for generating a signal which can be used to deactivate said heating elements upon the detection of a predetermined high temperature level by said temperature sensor.

In a secondary afterburner for reducing the pollutant level of flue gas resulting from the operation of primary combustion unit such as a fireplace or the like, the combination comprising:

• (a) a combustion unit enclosure having an interior afterburner chamber in an upper portion thereof and a debris floor in a lower portion thereof for the collection of debris from combustion products therein;
• (b) a lower inlet and an upper outlet in fluid communication with said afterburner passageway and adapted to be inserted in the flue passage of a chimney structure so as to provide fluid communication between said chimney flue and said interior passageway;
• (c) a conduit at said inlet extending into an opening into the interior of said combustion unit enclosure;
• (d) a transverse deflecting member within said combustion unit enclosure above said inlet conduit and defining with said conduit a lateral opening providing a flow passage for the lateral flow of combustion products flowing upwardly through said conduit;
• (e) a secondary deflecting member which extends downwardly and outwardly from said primary deflecting member and terminating in a downward projecting lip portion;
• (f) an upstanding rim projecting upwardly from the debris floor of said combustion unit and terminating at a location to provide with said lip portion, a second lateral opening for the egress of combustion products flowing laterally through said opening and thence upwardly to said afterburner passageway.

In a secondary afterburner for reducing the pollutant level of flue gas resulting from the operation of primary combustion unit such as a fireplace or the like, the combination comprising:

• (a) a combustion unit enclosure having an interior afterburner chamber in an upper portion thereof and a debris floor in a lower portion thereof for the collection of debris from combustion products therein;
• (b) a lower inlet and an upper outlet in fluid communication with said afterburner passageway and adapted to be inserted in the flue passage of a chimney structure so as to provide fluid communication between said chimney flue and said interior passageway;
• (c) a conduit at said inlet extending into an opening into the interior of said combustion unit enclosure;
• (d) a baffle system providing a tortuous flow passageway between the outlet of said conduit and said afterburner chamber and configured to provide a lateral flow passage leading to a downward flow passage of greater cross-sectional area than said conduit and a second lateral flow passage leading to an upper flow passage opening into said afterburner chamber and having a greater cross-sectional area than said downward flow passage.