Patent GB-670312-A (GB)
Title: Improvements in or relating to a method of generating heat and to a burner for carrying out said method
IPC: F23D14/00
Filed: 1947-08-12
Abstract: 670,312. Furnace fronts. STEVENS, A. H. (Combustion Processes Co.). Aug. 12, 1947, No. 22367/47. Class 51 (i). [Also in Group XI] The invention consists in a method of and burner for generating heat by means of a low velocity luminous unstratified or unlaminated combustion atmosphere wherein an expanding slowly moving core of combustible fluid surrounds a gaseous carrying vehicle (air, steam or carbon dioxide) to produce a primary flame of high heat value, which is then surrounded with low-velocity secondary air; the primary flame and surrounding secondary air then pass to an expansion-restraining heat-radiating bounding surface so that the cracking or dis-sociating of the combustible fluid and the transverse mixing of the gases are effected by the heat from the primary flame and the heat radiated from the bounding surface. The burner comprises an outer shell having a peripheral wall 1, closed by a rear wall 2, an inner shell having a peripheral wall 3, and a gas ignition tube 4. The outer shell is lined with a refractory material 7 which at one end abuts against an apertured flange 8 on the inner shell 3 and at the other end against a refractory lining of a furnace wall port, the so-lined space forming a combustion tunnel 9. Air is supplied at a pressure of 0.5 to 1.5 pounds per square inch through a pipe 12. Primary air passes through a branched duct 11 and valve 19, to an air tube 10. Secondary air passes through duct 13 and valve 20 into a chamber 14 and then through ports 15 in the flange 8 into the combustion tunnel 9. Gas is supplied at a pressure of 0.5 to 1.5 pounds per square inch through duct 16 and inlet tube 17 into a chamber 18 and then through an oblique annular passage 21 to a primary combustion chamber 22 formed in the ignition tube 4. Gas passing through the annular passage 21 mixes with primary air from tube 10 to be burnt in combustion chamber 22. The combustion gas entering the annular chamber 18 is preheated by contact with the outer wall of the ignition tube 4. In operation, a portion of the combustible gas passes forwardly along the interior surface of tube 4 to issue as a relatively thin layer surrounding the primary flame into the combustion tunnel 9 .to mix with secondary air passing through openings 15. This secondary air is heated by the refractory lining 7 and expands inwardly to produce transverse mixing with the outwardly expanding primary flame and combustion gases, issuing from the ignition tube 4, thus continuing the forward movement of the burning mass along the combustion tunnel 9. In a modification, Fig. 4, a duct 47 passes centrally through the rear closure wall into the ignition tube and has mounted on its forward end a jet nozzle 48 constructed to provide a fine jet of fluid under pressure to the centre of the primary flame issuing from the ignition tube. Superheated steam, carbon dioxide or like gases may be passed through jet 48. In a further modification for use with oil fuel, Figs. 7 and 9, ducts 123 and 125 pass through the rear closure wall 104 to terminate in a nozzle block 113 centrally disposed in chamber 121. Oil is fed through duct 123 to a nozzle 127 and impinges on a steam or air jet from a nozzle 128 and so enters the combustion tunnel 112. In a further modification of the burner for use with oil and gas, Fig. 15 (not shown), the burner is constructed as shown in Fig. 4 except that the duct 47 and jet nozzle 48 are replaced by the fuel and compressed air supply arrangement shown in Fig. 9. When the oil/gas burner is operated solely with gas the nozzle 113 and its fittings should be removed.