Furnace for Continuous Gas Curing, Especially of Rubber Products

Abstract

A continuous gas baking furnace includes elements for heating a baking area through which the product which is to be treated passes, formed by at least one module including a heat exchanger with a gas burner and elements for propelling and directing heated air towards a baking area, wherein the gas combustion circuit of the heat exchanger is separate from the circuit of hot air flowing through the baking area, the elements for directing the hot air include paths for directing hot air on both sides of the baking area and a path for evacuating air via the middle of the baking area. The furnace includes members for ensuring pyrolysis of gaseous effluents, the members treating a fraction of the gas circulating in a given section of the furnace, and at least one catalytic bed which is arranged on the hot air circuit.

1 . Furnace for continuous gas curing, especially of rubber products, comprising means for heating a curing area ( 29 ) through which the product to be treated passes, characterised in that it is formed by a module or a plurality of juxtaposed modules ( 1 ,  2 ,  3 ,  4 ), integrated within a production line and each comprising a suitably insulated housing ( 24 ,  25 ,  26 ), a heat exchanger ( 13 ,  14 ,  15 ,  16 ) with a gas burner ( 5 ,  6 ,  7 ,  8 ) and means ( 32 ,  33 ,  35 ,  36 ,  41 ,  42 ) for propelling and directing the heated air through the heat exchanger toward an area ( 29 ) for curing of the product, the gas combustion circuit of the heat exchanger being separate from the circuit of hot air flowing through the curing area, the means for directing the hot air also being distributed and set apart by grids ( 41 ,  42 ) along the curing area comprising paths ( 38 ,  39 ) for directing hot air on both sides of the curing area ( 29 ) and a path ( 40 ) for evacuating the air via the middle of the curing area, characterised in that it also comprises:
 means for pyrolysing gaseous effluents present in the air circuit and resulting from the curing of the product, said means treating a fraction of the gases travelling in a given portion of the furnace;   and at least one catalytic bed ( 76 ,  76 ′) interposed on the hot air circuit.   
   
   
       2 . Gas furnace according to  claim 1 , characterised in that said means for pyrolysing the gaseous effluents resulting from the product comprise means for adjusting said fraction of the gases that is treated by pyrolysis. 
   
   
       3 . Curing furnace according to  claim 1 , characterised in that the heat exchanger ( 13 ,  14 ,  15 ,  16 ) of each furnace module is an exchanger with a hairpin tube which is internally heated using a corresponding gas burner ( 4 ,  5 ,  6 ,  7 ), in that the means for propelling and directing hot air toward the curing area of each module comprise at least one ventilation turbine ( 32 ) arranged in proximity to the bottom of the housing of the module facing paths for directing hot air which are delimited by metal sheets ( 35 ,  36 ) for deflecting hot air to direct it either side of the curing area, and grids ( 42 ,  42 ) for distributing hot air along the curing area, and in that said means for pyrolysing said gaseous effluents comprise a casing ( 67 ) which is open at its two ends surrounding said hairpin tube ( 15   a ) and is positioned in the vicinity of said turbine, separated from said tube by a gap ( 68 ) and terminated facing said turbine ( 32 ). 
   
   
       4 . Furnace according to  claim 3 , characterised in that said casing ( 67 ) is provided with means for varying its distance from the turbine ( 32 ). 
   
   
       5 . Furnace according to  claim 3 , characterised in that said casing ( 67 ) is provided with means for varying its length. 
   
   
       6 . Furnace according to  claim 1 , characterised in that said catalytic bed ( 76 ,  76 ′) is based on one or more precious metals deposited on an inorganic support. 
   
   
       7 . Curing furnace according to  claim 2 , characterised in that the heat exchanger ( 13 ,  14 ,  15 ,  16 ) of each furnace module is an exchanger with a hairpin tube which is internally heated using a corresponding gas burner ( 4 ,  5 ,  6 ,  7 ), in that the means for propelling and directing hot air toward the curing area of each module comprise at least one ventilation turbine ( 32 ) arranged in proximity to the bottom of the housing of the module facing paths for directing hot air which are delimited by metal sheets ( 35 ,  36 ) for deflecting hot air to direct it either side of the curing area, and grids ( 42 ,  42 ) for distributing hot air along the curing area, and in that said means for pyrolysing said gaseous effluents comprise a casing ( 67 ) which is open at its two ends surrounding said hairpin tube ( 15   a ) and is positioned in the vicinity of said turbine, separated from said tube by a gap ( 68 ) and terminated facing said turbine ( 32 ). 
   
   
       8 . Furnace according to  claim 7 , characterised in that said casing ( 67 ) is provided with means for varying its distance from the turbine ( 32 ). 
   
   
       9 . Furnace according to  claim 4 , characterised in that said casing ( 67 ) is provided with means for varying its length. 
   
   
       10 . Furnace according to  claim 2 , characterised in that said catalytic bed ( 76 ,  76 ′) is based on one or more precious metals deposited on an inorganic support. 
   
   
       11 . Furnace according to  claim 3 , characterised in that said catalytic bed ( 76 ,  76 ′) is based on one or more precious metals deposited on an inorganic support. 
   
   
       12 . Furnace according to  claim 4 , characterised in that said catalytic bed ( 76 ,  76 ′) is based on one or more precious metals deposited on an inorganic support. 
   
   
       13 . Furnace according to  claim 5 , characterised in that said catalytic bed ( 76 ,  76 ′) is based on one or more precious metals deposited on an inorganic support.