Reed water tube boiler
The Reed water tube boiler was a type of water tube boiler developed by J. W. Reed, manager of the engine works at Palmers Shipbuilding and Iron Company of Jarrow, England, where it was manufactured from 1893 to 1905. Intended for use in the steam propulsion of ships, it was similar to other boilers such as the Normand and Yarrow, themselves developments of the du Temple boiler. About 170 of Reed's boilers were installed in ships of the Royal Navy, in two of which they were installed to replace boilers rejected by the Admiralty.
The Reed water tube boiler was developed and patented in 1893 by J. W. Reed, manager of the engine works at Palmers Shipbuilding and Iron Company, which manufactured it. It was similar to its antecedent the du Temple boiler, and other developments from it such as the Normand and Yarrow boilers, in that each featured three cylindrical water chambers arranged to form a triangle or, viewed from one end, an inverted "V" shape: the top chamber collected steam, and was connected by two banks of steam-generating tubes to the two lower chambers, between which was a furnace.
In the Normand boiler, the tubes were comparatively straight and a portion of those in the inner and outer rows of each bank were formed into "tube walls" to direct hot gases generated by the furnace through the boiler. In the Reed boiler, the tubes were bent into pronounced curves of varying radii to maximise surface area and therefore steam production, and baffles were used to direct hot gases. Further, the external diameter of the tubes tapered at their lower ends from 1 1⁄16 inches (27 mm) to 7⁄8 inch (22 mm) to improve the passage of hot gases between them. They were connected perpendicularly to the chambers at each end, as were the tubes in the Normand boiler, to reduce stress. However, in the Reed boiler these connections were made by hemispherical faces, which allowed "a certain angular play". The tubes were secured by nuts inside the chambers at each end.Handholes gave access to the bottom chambers, and a manhole gave access to the top chamber. In both types of boiler, the tubes joined the top chamber below the designed water line to stop them overheating, and large, external "down-comer" tubes transferred water from the top chamber to the two bottom ones. The down-comers thus promoted convection within the boiler, which needed to be rapid because of the small diameter of the tubes, and formed "a substantial part of [its] framework."
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