Show WASTE OF HEAT A Timely Hint to Those Engaged in Operation of Valley Smelters The waste of heat from any high temperature furnace whereof the pro ducts of combustion must be discharged at approximately the temperature of the furnace is a source of very large fuel consumption This can be minimized either by the Installation o means for preheating the air for combustion as In regenerative furnaces or by utilizing the waste heat for the generation of steam At one or two Eastern copper refineries steam boilers are Installed In connection with the melting furnaces The success of this arrangement as In all systems of heat recuperation is dependent de-pendent upon noninterference with the proper operation of the prime 1 furnace Itl is i obviously I better I t for the I latter t to do iiui it luquuuu lulu waste 111111 nan to bring about the reverse result Atone At-one Eastern refinery the attempt to generate steam in this manner proved a failure because of the diminished melting capacity of the furnace owing to the reduced draft which however is n difficulty that can easily be obviated obvi-ated by correct design of the combined unit On the other hand n certain Montana smelting plant has a 300horse power Sterling boiler with U019 square feet of heating furnace connected with a 50 by 20foot reverbcratory smelting furnace which has proved a great success suc-cess this furnace doing better work than neighboring furnaces of the same type without the boiler attachment The reason was that the other furnaces worked with undergrate blast had too strong a draft which drew the lames too quickly from the fireplace through the smelting chamber or laboratory of the furnace By Introducing the necessary i neces-sary dampers to control the draft the efilclency of these furnaces was brought up to that of the one with the boiler attachment The explanation of this experience Is to be found in a study of the principles o combustion In gas o firing a certain length o time is necessary neces-sary for combustion to develop fully and for the particles of Incandescent carbon to give olC their radiant heat the same is true of direct tiring to amore a-more or less extent In other words the burning gas must tar a while In the laboratory o the furnace and Its velocity through that part of the furnace fur-nace must be considered in order to oh tain the maximum heating effect of the fuel It the velocity be too great there will be a waste of energy up the chimney chim-ney and the desired result In the furnace fur-nace can only be attained by an increased in-creased consumption of coal on the nal Engineering and Mining Jour |