Patent GB-713062-A (GB)
Title: Heat exchanger
IPC: F22B21/26
Filed: 1949-09-26
Abstract: 713,062. Forced-flow steam boilers, tubular heat-exchange elements; recuperators. PAUKER, F. Sept. 26, 1949 [May 15, 1941; Nov. 27, 1941], Nos. 24709/49 and 24710/49. Classes 64(1), 64(3) and 123(2)  A heat-exchanger, e.g. a steam boiler, comprises tubes of circular cross-section and internal diameter of 1 to 3 mm. A steam boiler comprises three coaxial sets 3, 4, 5 of spirally wound tubes of 1 to 3 mm, diameter, the tubes in each set being wound like a multi-start screw-thread. The diameter of successive windings and the number of tubes connected in parallel in them are in the ratio of the series 1, 2, 3 &c. The annular spaces between the sets of tubes and the spaces at the centre form flues for hot gases from burners. In the part of the boiler where heating of the tubes is mainly by radiation, the tubes are closely wound so that adjacent coils touch one another, and heat-absorbing steatite or other refractory cylinders 11, 12, 13, which may be porous or perforated, are provided to increase radiation. Further on, where heating is mainly by conduction, the coils are spaced so that the hot gases can pass between them, and hollow cylindrical cores 14, 15, 16 are provided to divert the gases between the coils. Dust or gas may be added to the heating gases to increase radiation. Feedwater is supplied to the tubes through a central bundle of tubes 10. A pipe 18 enclosing these tubes acts as a combustion air inlet to a recuperator in which the exhaust combustion gases flow through tubes 17. The heated air from the recuperator flows through a jacket space in the casing around the coiled tubes, to the front of the boiler, and is admitted partly to the burners as primary air and partly to the flues as secondary air. The central space surrounded by the coils 3 may be occupied by a steam turbine or other steam engine, instead of acting as a flue. Another steam generator, Fig. 2, comprises a ring of spirally wound tubes 21 the coils of which interengage and may be welded together, In a modification there may be more than one ring of such tubes. Another form comprises coaxial sets of two concentric annular headers connected by curved tubes arranged to form a network. In a modification there may be more than two concentric headers in each set. The Specification as open to inspection under Sect. 91 comprises also a steam generator or other heat-exchanger, Fig. 4 (Cancelled), in which bundles of tubes 27 bent to triangular shape are connected to chambers 28 in rings 29. The central space may be occupied by a steam turbine. Each header ring may comprise two rings 30, 31, Fig. 5 (Cancelled), held together by screws 32, and an elastic ring 33 with a slot 37 having internal pressure. Jackets 40, 41, 42 enclose the rings. In a modification, the header rings comprise flat sealing rings which alternate with header rings each having recesses on one surface to form the header chambers. In another modification, the header rings have header recesses in both surfaces, and are clamped between annular inlet and outlet manifolds. In another form, Fig. 12 (Cancelled), a boiler comprises a number of units in each of which tubes 64 are connected to headers 65 with a central inlet 66 and outlets 67. In modifications of this, similar units of parallelogram shape are arranged to form a hexagon. In another steam generator, Fig. 15 (Cancelled), hot gases flow through the steam-generating section in the same general direction as the water and steam flow, and through the superheating section in the opposite direction to the steam flow. The steam-generating section comprises helical tubes 68 connected to annular inlet and outlet headers 70, 71, and the superheating section comprises helical tubes 69 connected to annular headers 74, 75, 76. In the tubes 68, the flow is from the header 70 to the header 71, and in the tubes 69, from the header 74 to the header 76. In all forms, the tubes may oscillate, at least partially transversely, relatively to one of the flowing fluids, to increase heat transfer and reduce flow resistance. This subjectmatter does not appear in the Specification as accepted.