Furnace

“ The “Reverberatory furnace” is a modification of the wind furnace, and is used to throw heat on to the surface of substances, as in roasting ores of metals, to drive off the sulphur, arsenic, &c., or in the making of soda, litharge, and other processes where the admission of hot air with the flame is either beneficial, or at least not detrimental; fig. 1 shows the construction of this kind of furnace. Blast furnaces are for the production of the very highest degrees of temperature, and in these the air is forced into the fire by blowing machines or bellows, often worked by steam-engines ”

“ The liability to imperfect construction and careless management often makes a furnace, especially a cast-iron one, a savor of death unto death rather than of health and comfort; also, when we are warmed by air thrown into a room at a high temperature, and dry at that, a greater degree of heat is necessary for comfort than if our bodies and clothing absorb heat from a radiating surface. The furnace, in short, compels us to breathe an atmosphere highly rarefied. ”

“ We place a furnace on the ground, and by means of a system of boilers, cylinder, piston, levers, shafts, and wheels, are enabled, in the topmost storey of a factory, to spin thread of gossamer fineness; and no intelligent person has ever witnessed the sight without being impressed with the marvellous dominion of man over the material world. But how puny, after all, is this effort compared to that which the working power of the sun exhibits! Here the furnace is not placed a few yards distant, but 95 millions of miles, and on what a stupendous scale! ”

“ The working breast of the hot furnace must be laid bare so as to open a breach for the extraction of the faulty pot, and the insertion of the fresh one, both in a state of bright incandescence. It is frightful to witness the eyes and fuming visages of the workmen, with the blackening and smoking of their scorched woollen clothes, exposed so long to the direct radiations of the flame. ”

“ But in the crucible and the open-hearth processes the temperature attainable is limited by the danger of melting the furnace itself, both because some essential parts of it, which, unfortunately, are of a destructible shape, are placed most unfavourably in that they are surrounded by the heat on all sides, and because the furnace is necessarily hotter than the steel made within it. ”

“ In the exterior wall, near its bottom, and opening on the lead flat, is a furnace of the commonest possible construction, and capable, from its free draught, of burning the commonest combustible material—such as inferior coal, coal screenings, coke, cinders, and sawdust. This furnace, encased in brickwork, is carried obliquely for a distance of four or five feet into the Calidarium; and its flue, following the angle of the floor, makes the circuit of the apartment. ”

“ If the furnace yields the right temperature, and the duration of the exposure to its action is neither too short nor too prolonged, nature makes up for the unskilful conduct of the operative, and removes the stumbling blocks which his ignorance had placed in the way of his own attempts at excellence. ”

“ But don't you see that the whole trouble is because you let the furnace out? The boiler itself is all right, but you see, gents, it feeds off the furnace.'
"'Ah,' said the Bishop in a deep melodious tone, 'it feeds off the furnace. Now that is most interesting. Let me repeat that; I must try to remember it; it feeds off the furnace. ”

“ A common furnace will sometimes exemplify the operation of forces which have produced the Giant's Causeway; and in a sloping ploughed field after rain we may often observe, at the lower end of a furrow, a handful of washed and neatly deposited mud or sand, capable of serving as an illustration of the way in which Nature has produced the deltas of the Nile and Ganges. ”

“ You pick up a shovel and run into a spell of fairly hot work for three quarters of an hour. On another day you may loaf for fifteen minutes before anything starts. After front-wall, you take a drink from the water fountain behind your furnace, and wash your arms, which have got burned a little, and your face, in a trough of water. A "clean-up" [Pg 146] job follows in front of the furnace, which means shoveling slag—still hot—down the slag-hole for ten minutes, and loading cold pieces of scrap, which have fallen on the floor, into a box. ”

“ When they got ready to draw the charge,—that's when the red-hot iron is about to flow out of the furnace, you know, the outlet got clogged. That's a bad thing to happen to a furnace; for if a chill should set in, the whole plant would be ruined. ”

“ The furnace is fired with coal on a grated hearth, built at the lower end; it is more economical both in fuel and in labour than an ordinary reverberatory furnace.
The Thwaite-Denny Revolving Furnace.—This new type of furnace, which is fired with gaseous fuel, is stated to combine the advantages of the Stetefeldt, the Howell-White, and the Brückner. ”

“ The furnace is very simple, being simply a wall surrounding an oblong space, a little smaller than the pan, so that the sides of the 30 latter may rest on the walls all round, except for a small space in front where the fuel is introduced, which apparently burns on the ground alone. ”

“ FURNACE AND I SUMMER is the favorite time to advertise furnaces, for, although a pacifist might argue that being prepared for cold weather encourages frost, the practical persons who make and sell heating plants are firm believers in preparedness. They produce diagrams and pictures, showing how their furnace bisects the coal bill, and how easily a pretty child can run it from the front hall. ”

“ During the process of charging the furnace the instructor explains the principle of its construction, and shows how it operates. At every subsequent rest in moulding the students surround the furnace to witness the progress of the fire, the position of the layers of coal, and the state of combustion. They pass the furnace in procession, and each peeps in through the isinglass windows upon the glowing fire, asks a question, or a dozen questions, perhaps, and gives place to the next student in line. ”

“ Considerable space has been given in the magazines and newspapers this winter to official and expert directions on How to Run Your Furnace and Save Coal—as if the two things were compatible. Some had accompanying diagrams of a furnace in its normal state, showing the exact position of the arteries and vitals, with arrows pointing in interesting directions, indicating the theoretical course of the heat.
I have given some time to studying these charts, and have come to the conclusion that when the authors of such articles and I speak the word "furnace," we mean entirely different things. ”

“ If you approach a large furnace, the first thing you see are the black columns of smoke rising up and towering aloft, and if you approach nearer you discover piles of coal and ore, and the ashes, dust, and cinders which have been heaved out ”

“ The principle of this furnace consists in utilising the heat of the products of combustion to warm up the gaseous fuel and air which enters the furnace. This is done by making these products pass through brickwork chambers which absorb their heat and communicate it to the gas and air currents going to the flame. An extremely high temperature is thus obtained, and the furnace has, in consequence, been largely used in the manufacture of glass and steel. ”

“ That precisely is what a blast furnace is. The hollow, cylindrical furnace is the mountain cone, charged from the top with fuel, iron ore and limestone flux. The mass is fired at the bottom. The gases go off at the top in flame and smoke, an upside-down cataract of lost affinities, giddy, voluptuous, hungry and free. An odd circumstance has released them from the cold [32] inert embrace in which they have lain for ages of years. Cinders and gross matter flow away below as lava. ”

“ Feeling confident, then, that I could rely upon them, I next turned to my furnace, which I had filled with numerous pigs of copper and other bronze stuff. The pieces were piled according to the laws of art, that is to say, so resting one upon another that the flames could play freely through them, in order that the metal might heat and liquefy the sooner. At last I called out heartily to set the furnace going. ”

“ The furnace is made to rock forward, and spill out a few hundred pounds of the slag that floats on top. A short "buggy" car runs under, to catch the flow. But somebody had blundered—no buggy was there when the slag came.
"Get him up queek, and let buggy come back for nex' time," explained an Italian with moustachios, who carried the pick. "Huh, whatze matter goddam first-helper, letta furnace go?" ”

“ They should never rest directly upon the sole of the furnace, but must have their bottom freely played upon by the flame, as well as the sides and top. The degree of heat is regulated by openings in the arch, or upon the long sides of the furnace, which lead to the chimney; as also by the greater or less quantity of air admitted below the grate, as in glass-house furnaces. ”

“ The forehearth is that part of the crucible projecting in front of the fire-walls of the furnace. Crucible furnaces are those shaft furnaces in which the curcible is entirely one the inside. They are divided into eye-crucible furnaces and tap-crucible furnaces. The former have an eye in the front wall from which the slag flows continuously, the metal and matter being tapped off at intervals into basins. ”

“ On the first chill day of winter you start your furnace to warm the house. It won't do just to light a fire, throw on some coal, slam the furnace door and let her heat up. That might be all sufficient if the cold spell only lasted a couple of hours. But the winter runs on, and blizzards get worse. To keep that furnace going full blast you must have plenty more coal, right handy in your cellar. No man is fool enough to light one fire, then sit down and depend upon voluntary contributions of coal that the neighbors may send in. ”

“ I picked up my shovel, and shoved it into the dolomite pile, with a slight pressure of knee against right forearm that eases your back. The thermometer in the shade outside was 95°. I wondered vaguely how much it was where Nick stood, with the doors open in his face.
We walked back together after the front-wall to the trough of water.
"Not bad when you get good furnace, good first-helper," he said. "Fred good boy, but furnace no good. A man got to watch himself on this job," he went on bitterly; "he pull himself to pieces." ”

“ The arrangement of the furnace and pots is shown in Figs. 1 and 2. A is the fireplace; B, the crucibles, eighteen in number, spread over the floor of the furnace in a single layer; c, d, e, and f are the flues for conducting away the heated gases arising from the calcination of the bones, as well as the waste heat itself; the last portion of the flue is fitted with a damper g. The furnaces are intended to be built in fours, back to back, the waste heat serving in a great measure to [8] conduct the operation of the revivifying apparatus placed in the centre of the group, and marked C. ”

“ In due time, and when the furnace is heated, the metal begins to flow, in a full stream, from an aperture for the purpose in the bottom of the floor, and is received into a basin, from which in time it is removed, by a ladle, into moulds made of moist sand, formed near the furnace. ”

“ About this time the two workmen open all the doors, and turn over the ore, each at his own side of the furnace. An hour and three quarters after the beginning, [755] there are few vapours in the furnace, its temperature being very moderate. No more lead is then seen to flow upon the sloping hearth. A little coal being thrown into the grate to raise the heat slightly, the workmen turn over the ore, and then close all the doors. ”

“ The fact that it is difficult to drive the [Pg 65] hot air against the wind raises a second objection, but if the furnace is placed in the corner of the house from which the cold winds blow, or even a second furnace is installed, the trouble will be largely overcome. ”

“ The plan of placing the furnace at the bottom of the pit is, however, more advantageous, because the shaft through which the air ascends to the furnace at the pit mouth, is always at the ordinary temperature; so that whenever the top furnace is neglected, the circulation of air throughout the mine becomes languid, and dangerous to the workmen ”

“ In many houses the rooms are heated only by the furnace, which is found in almost all houses—a great stove down below in the cellar, with pipes sent through the various rooms, and what are called registers. What impairs the beauty and youthfulness of the American women is, I believe, their hot fires and furnaces, and the dryness of the heat given by the anthracite coal. ”

“ A thousand degrees more convert it into vapour, and at last, by passing through the intense heat of a glass-house furnace, it is converted into a brilliant flame, and augments the heat of the furnace to a great degree. Hence the practice in glass-houses of throwing water into the ash-hole, the vapour of which, by passing through the burning fuel, makes the furnace much hotter than it was. ”

“ Everybody douses his face and hands with water to cool off, and sits down for twenty minutes. Making back-wall has affinities with stoking, only it's hotter while it lasts. The day is made up of jobs like these—shoveling manganese at tap-time, "making bottom," bringing up mud and dolomite in wheelbarrows for fixing the spout, hauling fallen bricks out of the furnace. ”

“ The burning mine, hundreds of feet down in the ground, was in effect to be his subsidiary furnace—his gas-producer.
These unburned gases, from the producer, pass, hot, into the furnace proper; either directly or sometimes after being conveyed a considerable distance—as they would have to be according to Jimmy’s plan. In this latter event they cool off, but are heated up again by the waste heat of the furnace. ”