GB838265A - Improvements in steam boilers for marine use - Google Patents

Abstract

838,265. Vertical steam boilers. HUET, A. June 27, 1958 [June 27, 1957], No. 20744/58. Class 123 (2) A steam boiler for marine use, in which variations in inclination caused by the ship movement do not affect the water level, consists of a number of units such as that shown in Fig. 1. Each unit has an upright, double-walled, cylindrical casing a containing a large number of heat exchanger tubes the space between which is packed with an insulant such as glass wool. Each heat exchanger tube, Fig. 3, comprises an external tube b, which may be corrugated as at c, containing a coaxially-mounted tube d provided with external fins e. A heat transfer fluid, for example, high pressure water or gas or a liquid metal, enters the unit at f and is distributed from a header g to the top inlet tubes i of the tubes b. The fluid leaves the tubes through outlets j, is collected in a header l and leaves the unit through a pipe n for reheating. Water enters the casing jacket q at o and flows downwardly therein. Tubes s convey the partly heated water from the jacket to respective tubes d the bottom portions of which are formed with a velocity-increasing throat t having helical vanes u. The water is preheated in the lower part of the tube which contains a core 1 and evaporated in the upper part which has a helical baffle u<SP>1</SP> which spins the water on to the tube wall, the steam rising along the axis of the tube and discharging through a pipe v to a header wand collector x whence pipes y lead the steam to a superheater or directly to the point of use. Unevaporated water is withdrawn from the tube d through a pipe 3 leading to a separator 4 wherein steam is removed, the water being returned by a pump 5 to the tube inlet. Inclination of the casing does not greatly affect the water levels in the large number of small diameter individual tubes so that the overall level in the casing is substantially unchanged.