| 摘要 |
1,097,352. Burners; air preheaters. HOTWORK Ltd. Dec. 15, 1966 [Dec. 20, 1965], No. 53913/65. Headings F4S and F4T. A burner inserted in a furnace wall 10 comprises a tubular member 14 defining a combustion zone which is supplied with gaseous fuel and air, the air having been preheated by combustion gases in an annular heat exchanger 26 surrounding the gas fuel inlet pipe 23. Heated air is supplied from the heat exchanger through openings 27p to a chamber 16 from which it is distributed to the combustion zone via annular spaces between casing 14 and tube 18, and between tube 18 and tube 17. Gaseous fuel is supplied to the latter space from pipe 23 through lateral branches 25. Fuel oil may be supplied through a nozzle 47. Combustion gases are drawn from the combustion zone via an apertured shroud 36 to the heat exchanger by means of compressed air injected into the exhaust pipe 42 through nozzle 43. The heat exchanger 26 comprises concentric tubes 29 defining a plurality of annular passages 31 surrounding the gas pipe 23. Annular headers 27, 28 at each end of the tubes comprise open ended rings 27c 28c which each carry six radial webs 27d, 28d defining six segmented chambers 27c, 28c. Arcuate ribs 27f, 28f extend between the webs, the ribs in each segmented chamber being offset radially with respect to the ribs in adjacent chambers, and the ribs in each chamber being arranged to close alternate annular passages defined by the tubes 29, so that one set of alternate annular passages is connected to one set of alternate chambers in both headers, and the other set of alternate passages is connected to the other set of alternate chambers in both headers. Heat exchange takes place through the walls of the tubes 29 since the gases may flow through the blind portions of the passages 31 from adjacent open portions. In a second embodiment of the invention, Fig. 5, a tubular member 54 forms a combustion space 65 and a block 56 of refractory material closes the inlet end of this space and is connected to the member 54 by circumferential rods 59. A gas supply pipe 60 passes through the centre of block 56 and air is supplied from a chamber 73 through pipes 78 passing coaxially within an annular array of bores 75 in the block. From the pipes 78 the air enters an annular cavity 66 before passing to the combustion space via radial openings 67. Combustion gases are drawn from the space 65 via the bores 75 to a chamber 72 by the ejector effect of air passing from chamber 73 through a nozzle 81. |
