Abstract
A NOTABLE paper was read to the Institution of Electrical Engineers on February 15 by F. Ohlmiiller on the Benson boiler and its development for use in power stations. Dr. Mark Benson came to Great Britain some years ago and with the help of the English Electric Co. carried out experiments on a 500 h.p. steam turbine built for the purpose of working with steam evaporating at the critical pressure (3,200 Ib. per sq. in.). At this pressure the latent heat of water is zero. The water being heated to the critical temperature (706° F.) turns completely and instantaneously into steam. Unlike ordinary boilers there is no separation of steam from water. In the present design of the boiler, dry steam is produced with certainty in steel tubes. At the outset, many difficulties had to be overcome. The manufacturing rights are now the property of the Siemens-Schuckert Co. of Berlin. They have overcome the trouble experienced with the tubes at Rugby. They now manufacture tubular boilers for use both at the critical and at subcritieal pressures. Tests showed that the burning out of the tubes was due to the precipitation of salts contained in the feed water on the parts of the tubes where the water changes into steam. This occurs in the zone where evaporation terminates and superheating begins. The remedy is to change the zone of deposit to a region of lower flue-gas temperature.
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Boilers for Critical Pressure. Nature 133, 287 (1934). https://doi.org/10.1038/133287a0
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DOI: https://doi.org/10.1038/133287a0