GB1096302A - Improved shell and tube type boiler - Google Patents

Abstract

1,096,302. Return tube steam and hot-water boilers. MARSHALL SONS & CO. Ltd. Oct. 2, 1964. [July 4, 1963], No. 26496/63. Heading F4A. In a shell and tube type boiler for generating steam or heating water, the water space 4 is defined by a tubular metal shell 1 with front and rear tube-plates 2 and 3 extending across the bore of the shell at each end. A smaller tube plate 5, conveniently being between one-half and two-thirds of the diameter of the tubeplates 2 and 3, is joined to the rear tube plate 3 by a metal ring 6 to form a combustion chamber 12. A wide bore burner tube 10 which opens into the combustion chamber 12 extends through the water space 4 to the front tube-plate 2 at which end is situated a burner 11. A first group of tubes 7 connected to the combustion chamber 12 extend through the water space to the front tube-plate 2 and open into a front gas-reversal chamber 15 formed by part of a hinged and davited front door 8, provided with refractory lining 8a, and a partition 16 attached to the door 8. A second group of tubes 7 connected to the front gas-reversal chamber 15 extend through the water space to the rear tube-plate 3 and open into a rear gas-reversal chamber 18 formed by a hinged and davited rear door 9, provided with refractory lining 9a, which supports a refractory member 13 separating the combustion chamber from the gas-reversal chamber 18. A third group of tubes 7 connected to the rear gas-reversal chamber 18 extend through the water space to the front tube-plate 2 and open into a flue chamber 20 formed by part of the front door 8 and separated from the front gas-reversal chamber by the partition 16. The total cross-sectional area available to the combustion gases that flow through the groups of tubes is reduced successively at each tube group. The tubes of the various group may be plain, gilled or convoluted and the burner tube 10 may be corrugated. In a modification, a fourth and even a fifth group of tubes may be added to increase the number of passes made by the combustion gases, gas-reversal chambers and the flue chamber being arranged at the appropriate ends to allow continuous flow. In the embodiment shown, the front door 8 is formed with a suitable aperture in which the burner 11 is disposed to project into the burner tube 10 but, in a further modification, a second separate front door, disposed on the outside of the door 8, may be employed to support the burner 11.