Catalytic combustion heating apparatus

Abstract

A water repellent material, such as PTFE layer, is provided by coating on the surface of a Pt catalyst. A catalytic carrier supporting the Pt catalyst is a metallic tube, such as an aluminum tube. The coolant acting as a heating medium is supplied into this metallic tube. According to this arrangement, the catalyst surface is not covered with the moisture contained in the air, the moisture contained in the fuel gas, or the moisture contained in the exhausted catalytic combustion gas. The catalyst can directly contact with a fuel mixture. The catalyst function does not deteriorate. A sufficient amount of catalytic combustion heat is generated. Accordingly, the catalytic combustion heater can quickly increase the catalyst temperature to the activation temperature within a short time. Furthermore, the temperature of the PTFE layer can be maintained at a temperature range not exceeding its heat-resisting limit.

1 . A catalytic combustion heating apparatus comprising: 
 gas mixing means for forming a fuel mixture of air and fuel;    air supplying means for supplying said air to said gas mixing means;    fuel supplying means for supplying said fuel to said gas mixing means;    a passage connected to said gas mixing means and receiving said fuel mixture formed by and supplied from said gas mixing means;    a catalyst supported by a catalytic carrier and disposed in said passage; and    a heat exchanger receiving a heating medium and disposed at a downstream side of said catalytic carrier in a flowing direction of said fuel mixture in said passage, to perform heat exchange between said fuel mixture and said heating medium,    wherein    catalytic combustion of said fuel mixture is caused in said catalyst and the generated catalytic combustion heat is transferred via said heat exchanger to said heating medium, and    said catalyst possesses a water repellent function.    
     
     
         2 . The catalytic combustion heating apparatus in accordance with  claim 1 , wherein a water repellent material is provided on said catalyst to give said water repellent function to said catalyst.  
     
     
         3 . The catalytic combustion heating apparatus in accordance with  claim 1 , wherein said catalytic carrier is made of a water repellent material to give said water repellent function to said catalyst.  
     
     
         4 . The catalytic combustion heating apparatus in accordance with  claim 3 , wherein a water repellent material is provided on said catalyst.  
     
     
         5 . The catalytic combustion heating apparatus in accordance with  claim 1 , wherein said catalytic carrier includes a plurality of metallic tubes disposed parallel to each other and normal to the flowing direction of said fuel mixture, said metallic tubes have both ends opened to an annular passage, and said heating medium is supplied into said annular passage and said metallic tubes.  
     
     
         6 . The catalytic combustion heating apparatus in accordance with  claim 1 , wherein an auxiliary catalytic carrier supporting an auxiliary catalyst is disposed between said catalytic carrier and said heat exchanger in the flowing direction of said fuel mixture in said passage.  
     
     
         7 . The catalytic combustion heating apparatus in accordance with  claim 1 , wherein said fuel is hydrogen gas.  
     
     
         8 . A catalytic combustion heating apparatus comprising: 
 gas mixing means for forming a fuel mixture of air and fuel;    air supplying means for supplying said air to said gas mixing means;    fuel supplying means for supplying said fuel to said gas mixing means;    a passage connected to said gas mixing means and receiving said fuel mixture formed by and supplied from said gas mixing means; and    a heat exchanger receiving a heating medium and disposed in said passage to perform heat exchange between said fuel mixture and said heating medium,    wherein    catalytic combustion of said fuel mixture is caused by a catalyst and the generated catalytic combustion heat is transferred via said heat exchanger to said heating medium,    said heat exchanger includes a plurality of tubes each having an inner passage in which said heating medium flows and fins each being disposed in a space between neighboring tubes for receiving heat transferred from said tubes,    said catalyst is supported on at least one surface of said tubes and said fins, and    said catalyst possesses a water repellent function.    
     
     
         9 . The catalytic combustion heating apparatus in accordance with  claim 8 , wherein a water repellent material is provided on said catalyst to give said water repellent function to said catalyst.  
     
     
         10 . The catalytic combustion heating apparatus in accordance with  claim 8 , wherein said fuel is hydrogen gas.