Gas Fired Heating Device and a Method of Generating a Flow of Hot Air

Abstract

The invention relates to an apparatus for the heating of roofing material. The apparatus comprising: air supply means ( 86 ); an elongated tubular combustion chamber ( 10 ) with a first end ( 11 ) and a second end and having a wall ( 30 ) surrounding a longitudinal axis (A) of said combustion chamber ( 10 ) and including an exit for hot air at said second end ( 12 ) and at least one air entrance ( 50 ) near said first end ( 11 ) for delivery of a primary air flow. A burner arrangement is disposed essentially centrally within said combustion chamber near said first end. The burner arrangement comprises means for injection of fuel ( 88 ) and means for ignition of said fuel ( 80 ). The first end ( 11 ) of the combustion chamber being essentially air-tight, and said at least one air entrance ( 50 ) being located in the wall ( 30 ) of the combustion chamber ( 10 ) near said first end ( 11 ). The air entrance ( 50 ) comprises means to produce a helical current of air around said longitudinal axis (A) of the combustion chamber ( 10 ). The invention also relates to a method of generating a flow of hot gases in an apparatus for heating of roofing material

1 . An apparatus for the heating of roofing material, the apparatus comprising: 
 air supply means    an elongated tubular combustion chamber with a first end and a second end and having a wall surrounding a longitudinal axis of said combustion chamber and including an exit for hot air at said second end and at least one air entrance near said first end for delivery of a primary air flow;    a burner arrangement disposed essentially centrally within said combustion chamber near said first end, said burner arrangement comprising means for injection of fuel and means for ignition of said fuel;    said first end being essentially air-tight, and said at least one air entrance being located in the wall of the combustion chamber near said first end, the air entrance comprising means to produce a helical current of air around said longitudinal axis of the combustion chamber.    wherein the apparatus comprises a means for introducing a secondary helical current of air, the secondary current of air having a direction of rotation opposite the direction of rotation for the primary air and being introduced further downstream the combustion chamber.    
   
   
       2 . Apparatus according to  claim 1 , wherein said at least one air entrance comprises an angled scoop, an angled hole or an angled tube.  
   
   
       3 . Apparatus according to  claim 1  wherein said burner arrangement comprises a fuel-injecting means adapted to inject the fuel in a direction essentially concentrically with said longitudinal axis of the combustion chamber.  
   
   
       4 . Apparatus according to  claim 1 , wherein said burner arrangement has a wall means adapted to fit said apparatus to make said combustion chamber air-tight at said first end.  
   
   
       5 . Apparatus according to  claim 4 , wherein said burner arrangement is releasably connected to the combustion chamber.  
   
   
       6 . Apparatus according to  claim 1 , wherein the location of the air entrance is at or downstream of said means for injection of fuel.  
   
   
       7 . Apparatus according to  claim 1 , wherein the location of the air entrance is at or downstream of both said means for injection of fuel and said means for ignition of said fuel.  
   
   
       8 . Apparatus according to  claim 1 , wherein by the means to introduce the secondary helical current of air comprises at least one angled scoop; an angled hole or an angled tube.  
   
   
       9 . Apparatus according to  claim 8  wherein the apparatus comprises a mixing chamber arranged in extension of said combustion chamber at said second end, in which mixing chamber the mixing of the currents of primary and secondary airflows takes place.  
   
   
       10 . Apparatus according to  claim 9 , wherein the apparatus and the chamber arranged in extension of said combustion chamber are releasably connected.  
   
   
       11 . Apparatus according to  claim 1 , wherein a generally tubular housing surrounding said combustion chamber is included.  
   
   
       12 . Apparatus according to  claim 11 , wherein said combustion chamber and said housing are arranged at least partially in spaced apart, thereby defining an air gap for delivering said secondary air to said chamber, whereby said housing is maintained relatively cool during the operation of said apparatus.  
   
   
       13 . Apparatus according to  claim 12 , wherein a helical spiral placed in said air gap and bounded by the inside of the tubular housing and the outside of the combustion chamber generates the helical motion of the secondary air.  
   
   
       14 . Apparatus according to  claim 13 , wherein the air gap near said first end of the combustion chamber constitutes the initial air path for both primary and secondary airflows, said air path being subdivided into two separate air paths for primary and secondary air.  
   
   
       15 . A method of generating a flow of hot gases in an apparatus for heating of roofing material, said method comprising: 
 feeding a flow of combustible gas into a combustion chamber;    delivering a primary airflow in a direction essentially tangentially to the longitudinal axis of said combustion chamber;    directing a discharge end of said combustion chamber towards said roofing material;    igniting the mixture of gas and air inside the combustion chamber;    ejecting a flow of hot gases from said combustion chamber;    feeding a secondary airflow downstream of the entry of primary air, the secondary airflow having a direction of rotation opposite the direction of rotation for the primary airflow.