Radiant heating pipe

Abstract

Provision is made of a radiant heating pipe 10 which is designed to conduct hot gas through a central portion 14 in a preferred direction of flow SV, directed away from the burner 22 , into at least one return portion 16, 18 and preferably at least partially back into the central portion 14 , such that a recirculation flow through the radiant heating pipe 10 is produced overall. The smallest flow cross section D A for the gas in a zone 24 , close to the burner, of the central portion 14 is smaller than the smallest flow cross section D E in a zone 26 remote from the burner. Preferably, the radiant heating pipe 10 according to the invention has a waist at the transition from a branching portion 13, close to the burner, to the central portion 14.

1 . Radiant heating pipe ( 10 ) comprising:
 a burner connection ( 12 ),   a branching portion ( 13 ),   a central portion ( 14 ) and at least one return portion ( 16 ,  18 ) located next to the central portion ( 14 ), said return portion ( 16 ,  18 ) forming a loop with the central portion ( 14 ),   wherein the central portion ( 14 ) comprises a zone ( 24 ) close to a burner, said zone adjoining the branching portion, and a zone ( 25 ) remote from the burner connection ( 12 ), and   wherein the zone ( 24 ) close to the burner has a smallest diameter (D A ) that is smaller than a smallest diameter (D E ) of the zone ( 26 ) remote from the burner.   
     
     
         2 . Radiant heating pipe as in  claim 1 , wherein a cross-section of the central portion ( 14 ) widens in a preferred direction of flow (S V ). 
     
     
         3 . Radiant heating pipe as in  claim 2 , wherein the central portion ( 14 ) is conical. 
     
     
         4 . Radiant heating pipe as in  claim 1 , wherein a ratio of the smallest diameter (D A ) of the zone close to the burner to the smallest diameter (D E ) of the zone remote from the burner is less than ⅔. 
     
     
         5 . Radiant heating pipe as in  claim 1 , characterized in that a diameter of an opening ( 21 ) of the burner connection ( 12 ) is greater than the smallest diameter (D A ) of the zone ( 24 ) close to the burner. 
     
     
         6 . Radiant heating pipe as in  claim 1  further comprising a total of two return portions ( 16 ,  18 ), each forming a loop with the central portion ( 14 ). 
     
     
         7 . Radiant heating pipe as in  claim 6 , wherein the central portion ( 14 ) has a longitudinal axis (L), and that the return portions ( 16 ,  18 ) extend parallel to the longitudinal axis (L) of the central portion ( 14 ). 
     
     
         8 . Radiant heating pipe as in  claim 1 , wherein the central portion ( 14 ) and the at least one return portion ( 16 ,  18 ) are located on one plane. 
     
     
         9 . Radiant heating pipe, wherein the central portion ( 14 ) and the at least one return portion ( 16 ,  18 ) consist of sheet steel or cast steel. 
     
     
         10 . Radiant heating pipe as in  claim 1 , wherein the burner ( 22 ) is connected to the burner connection ( 12 ). 
     
     
         11 . Radiant heating pipe as in  claim 10 , wherein the burner ( 22 ) is a burner ( 22 ) adapted for flameless oxidation.