GB818730A - Improvements relating to heat-exchangers - Google Patents

Abstract

818,730. Fluid heaters. GREAVES & SON Ltd., A. E. Nov. 21, 1957 [Feb. 1, 1957], No. 3495/57. Classes 64(1) and 64(3) In apparatus for heating air or other fluid, hot gases from a central chamber 2 flow from an outlet at one end thereof through a plurality of exhaust flues 3 which are spaced from the chamber wall to provide a passage 6 for the air or other fluid which is heated in flowing transversely over the central chamber between the latter and the exhaust flues, the heating gases flowing back and forth in two passes through the flues 3 to an exhaust outlet 28 adjacent the gas outlet end of the central chamber 2. In the air heater shown, the gas passes in the exhaust flues are provided by partitions 24 (Fig. 7) and an outer casing 12 surrounds and is spaced from the heat exchanger so that some of the air is heated in flowing between the flues and the outer casing. The central chamber 2 may, as shown, comprise a combustion chamber having a liquid or gas fired burner 22 at one end, combustion air being tapped off through a duct 24 from the stream of air passing to the heat exchanger. Alternatively the heat source may comprise exhaust gases from an external furnace or combustion chamber supplying two or more of the heat exchangers mounted thereon (Figs. 8 and 9, not shown). The apparatus may be arranged with the axis of the heat exchanger disposed horizontally (as shown) or vertically. Support for the rear ends of the flues is provided by a plate 23 which closes the rear ends of the flues 7 and which is slidable on the outer surface of the central chamber 2 to allow for relative thermal expansion between these components and similarly a sliding or resilient joint is provided where the exhaust outlet 28 passes through the front wall 13a of the outer casing. Specification 773,155 is referred to.