Pellet burner

Abstract

Burner for particulate fuel, above all pellets such as bio-pellets, comprising a chute ( 10 ) having a longitudinal axis ( 11 ), the chute having a generally horizontally oriented longitudinal axis and having an inner wall of an essentially cup-shapedly upwardly open cross-section shape, a feeding device ( 30 - 34 ) for feeding a bed ( 20 ) of the particulate matter in and along the chute ( 10 ), and a device ( 40 ) for supply of primary air to the bed ( 20 ) in the chute ( 10 ), characterized in that the primary air supply device ( 40 ) is arranged to, without contact, direct primary air from above toward the free top-side of the bed ( 20 ) in the chute.

1 . Burner for particulate fuel, above all pellets such as bio-pellets, comprising a chute ( 10 ) having a longitudinal axis ( 11 ), the chute having a generally horizontally oriented longitudinal axis and having an inner wall of an essentially cup-shapedly upwardly open cross-section shape, a feeding device ( 30 - 34 ) for feeding a bed ( 20 ) of the particulate matter in and along the chute ( 10 ), and a device ( 40 ) for supply of primary air to the bed ( 20 ) in the chute ( 10 ), the primary air supply device ( 40 ) being arranged to, without contact, direct primary air from above toward the free topside of the bed ( 20 ) in the chute, characterized in that the supply device ( 40 ) has one or more primary air outlet openings ( 410 ) that along a substantial portion of the length of the chute ( 10 ) direct primary air downward close by the inside of each one of the upper edge parts ( 11 ) of the chute ( 10 ). 
   
   
       2 . Burner according to  claim 1 , characterized in that primary air supply device comprises one or more outlet openings ( 411 ) that direct primary air toward the free topside of the bed in the transversally central area of the bed. 
   
   
       3 . Burner according to  claim 1 , characterized in that the primary air supply device has one or more air outlet openings directed to lead primary air over substantially the entire width of the free surface of the bed along at least one longitudinal section of the chute ( 10 ), whereby a crust ( 21 ) of combustion deposits being established on the top surface of the bed ( 20 ) when burning the particle bed, if the ashes vitrify. 
   
   
       4 . Burner according to  claim 1 , characterized in that one or more of said at least one primary air outlet opening of the supply device are in the form of a slot extending along a substantial part of the length of the chute. 
   
   
       5 . Burner according to  claim 1 , characterized in that the air outlet openings for primary air are in the form of a row of openings extending along a substantial part of the length of the chute. 
   
   
       6 . Burner according to  claim 1 , characterized in that the supply device has one or more openings for blowing in secondary air toward an area above the bed ( 20 ) in the chute ( 10 ). 
   
   
       7 . Burner according to  claim 1 , characterized in that the chute is double-walled, and that primary air and possibly also secondary air is led through a hollow space ( 12 ) in the double-wall chute to a supply device ( 40 ) extending along the upper edge of the respective wall of the chute ( 10 ). 
   
   
       8 . Burner according to  claim 1 , characterized in that the air supply device ( 14 ,  40 ) extends along the upper edge of the respective side wall of the chute ( 10 ).