Fuel ignition systems

Abstract

Disclosed is a furnace adapted for burning solid materials, including biomass fuels. The furnace comprises an igniter having a heating element carried by a ceramic core and disposed within a ceramic cover tube for directing air at fuel disposed within the furnace for the purpose of igniting the fuel. Also disclosed is an igniter having a heating element carried by a ceramic core and disposed within a ceramic cover tube for directing air at fuel disposed within the furnace for the purpose of igniting the fuel.

1 . An apparatus for burning solid fuel, comprising: 
 a) a burning chamber for receiving fuel in communication with a fuel inlet, an air inlet, an exhaust outlet and at least one igniter, the at least one igniter comprising 
 i) an inlet block defining a channel therethrough, the inlet block including structure defining first, second and third orifices in communication with the channel;  
 ii) a seal disposed within the second orifice;  
 iii) a ceramic cover tube having first and second ends, the first end of the ceramic cover tube operably secured in the first orifice to the inlet block and the second end in communication with the burning chamber;  
 iv) a ceramic core disposed within the ceramic cover tube,  
 v) a heating element carried by the core, and  
 vi) electrical leads in electrical communication with first and second ends of the heating element, the electrical leads passing through the seal; and  
   b) a control circuit connected to the electrical leads; and    c) a gas source in communication with the third orifice for forcing a gas through the channel, into the ceramic cover tube, and out through the second end of the ceramic cover tube into the burn pot assembly.    
   
   
       2 . The apparatus of  claim 1 , wherein the apparatus further comprises a fuel feed mechanism in communication with the fuel inlet.  
   
   
       3 . The apparatus of  claim 2 , wherein the fuel is a biomass fuel.  
   
   
       4 . The apparatus of  claim 3 , wherein the biomass fuel is dried, shelled corn.  
   
   
       5 . The apparatus of  claim 1 , wherein the ceramic cover tube of the at least one igniter is constructed from a material selected from the group consisting of alumina.  
   
   
       6 . The apparatus of  claim 1 , wherein the ceramic core of the at least one igniter is constructed from a material selected from the group consisting of alumina, mullite and corderite.  
   
   
       7 . The apparatus of  claim 5 , wherein the ceramic cover tube has an outer diameter of about 0.5 inches.  
   
   
       8 . The apparatus of  claim 1 , wherein the heating element of the at least one igniter is rated between 300 and 600 watts at 120 volts AC.  
   
   
       9 . The apparatus of  claim 8 , wherein the heating element of the at least one igniter is rated at about 500 watts at 120 volts AC.  
   
   
       10 . The apparatus of  claim 9 , wherein the gas source delivers a gas flow of 25-30 SLPM at 25-35 IN-WC.  
   
   
       11 . An igniter, comprising 
 an inlet block defining a channel therethrough, the inlet block including structure defining first, second and third orifices in communication with the channel;    a ceramic cover tube having first and second ends, the first end of the ceramic cover tube secured in the first orifice to the inlet block;    a ceramic core disposed within the ceramic cover tube,    a heating element carried by the core, and    at least one electrical lead in electrical communication with a first end of the heating element, the at least one electrical lead passing through the second orifice.    
   
   
       12 . The igniter of  claim 11 , wherein a second electrical lead is connected to a second end of the heating element, the second electrical lead passing through the second orifice.  
   
   
       13 . The igniter of  claim 12 , wherein the second orifice is sealed against airflow.  
   
   
       14 . The apparatus of  claim 11 , wherein the ceramic cover tube is constructed from a material selected from the group consisting of alumina, mullite and corderite.  
   
   
       15 . The apparatus of  claim 11 , wherein the ceramic core is constructed from a material selected from the group consisting of alumina, mullite and corderite.  
   
   
       16 . The apparatus of  claim 11 , wherein the ceramic core is hollow.  
   
   
       17 . The apparatus of  claim 11 , wherein the heating element of the at least one igniter is rated between 300 and 600 watts at 120 volts AC.  
   
   
       18 . The apparatus of  claim 17 , wherein the heating element of the at least one igniter is rated at about 500 watts at 120 volts AC.  
   
   
       19 . The apparatus of  claim 11 , wherein the ceramic cover tube has an outer diameter of about 0.5 inches.  
   
   
       20 . The apparatus of  claim 11 , wherein the temperature of a gas is delivered at 25-30 SLPM at 25-35 IN-WC to the inlet block and exiting the ceramic cover tube is about 1100°-1300° C. when the heating element is connected to a 120 volt AC power source.