GB669156A - Improved furnace installation - Google Patents

Abstract

669,156. Returning combustion products to furnaces. AKT.-GES. FUR TECHNISCHE STUDIEN: Nov. 24, 1949 [Dec. 24, 1948], No. 30148/49. Class 51 (i). In an air heating furnace installation adapted for the re-circulation of combustion products to the furnace chamber, a fluid fuel or pulverulent fuel burner 3 surrounded by a cylindrical jacket 4 defining an air chamber 5 with a narrowed forward outlet 24 is supplied with combustion air from a chamber 11 and re-circulated combustion products from a zone 17 of the chamber 11 under control of an annular slide-valve 6. Air heating tubes 2.may be disposed in the combustion chamber 1 from which waste gases pass by a pipe 12 to an exhaust turbine 13 which drives a fan 7 supplying air through a pipe 8 either to the chamber 5 under control of a valve 18 or to the chamber 11 under control of a valve 10 and also drives a fan 14 which extracts some of the waste gases from said chamber 1 and returns them through a pipe 16 to a chamber 17. On starting, with the valve 6 closed, an additional air fan 21 supplies air to the chamber 5 under control of a valve 23 until the exhaust gas turbine 13 commences to function, after which the fan 21 is stopped and the valve 6 closed. In a modification, Fig. 2 (not shown), the annular slide valve 6 is replaced by flapvalves which direct the re-circulated combustion products either around the burner to mix with the combustion air or in front of the burning zone in the form of a sheet of gases protecting the combustion chamber walls.