Open hearth furnace

“ Herb looked interested.
"Of course, on the open-hearth you pick them up with a tongs, when they're red-hot, and cool them in water."
Herb nodded.
"So there are always halves of test-ingots on the floor, cold. On the blast-furnace the stove-tender pours the test and knocks it out of the mould. Iron breaks easier than steel, so he never bothers to cool the ingot, but breaks it red-hot. Last Wednesday I wander up from the stoves when the furnace is ready to tap. ”

“ But to-night I had time, and at quarter of twelve hung my shirt on the hot bricks at the side of the furnace, and stood near the doors in the heat, to dry my back and legs. I then washed soot and dolomite dust from ears and neck, and dipped my left arm, which was burned, in cold water. At twelve I put on the dried shirt, and went to eat.
Half the men wash, half don't. There were a number of open-hearth helpers in the restaurant, [Pg 74] with black hands and faces, two eating soup, two with their arms on the counter. Their faces lacked any expression beyond a sullen fatigue ”

“ It is merely a place of many ditches, or run-ways, that lead the molten iron from the furnace to the ladle. Very little iron is ever "cast," since the blast-furnaces here make iron only for the sake of swiftly transporting it, while still hot, to the Bessemer and open-hearth, for further metamorphosis into steel. ”

“ A blast-furnace, once lit, remains burning till the end of its existence. I got inside her, and was delighted to satisfy a deep-seated curiosity: we crawled in the cinder notch. The hearth of the furnace lay six or eight feet below the brick flooring, and the effect of standing inside, with the fourteen round blowpipe holes admitting a little sunlight, was like being in a round ship's cabin, with fourteen portholes, except that the hollow furnace shot up to dark distances that the light didn't penetrate. ”

“ However, a furnace properly attended will not need firing during church service. Remember, a large volume of warm air is what you want, and not a small volume of hot air. Never cover the grating or close the cold-air duct to cool off while there is fire in the furnace, but open the doors or windows of the church and check the fire. The closing of the grating or cold-air duct will injure the castings of the furnace by overheating them. ”

“ After all, that is the only real open fire. Wood is the fuel for it. Out-of-doors is the place for it. A furnace is an underground prison for a toiling slave. A stove is a cage for a tame bird. Even a broad hearthstone and a pair of glittering andirons—the best ornament of a room—must be accepted as an imitation of the real thing. The veritable open fire is built in the open, with the whole earth for a fireplace and the sky for a chimney. ”

“ As the temperature increases, if without any apparent defects in the bone-ash cupel, or hearth, which it may now be termed, the wind or blast, generally driven by a fan, is thrown in through a nozzle, or an aperture in the furnace, which, for facilitating the immediate removal of the bone-ash hearth, is placed upon an iron car, and runs beneath the vault of the furnace on rails, so that it may thus be very readily withdrawn when found necessary. ”

“ The cinder notch was likewise thoroughly provided with soaked shavings. That was to be the torch.
Men assembled as at a house-raising. Nobody [Pg 137] worked from 11.00 to 12.00 on the day of blowing in Number 9. From all parts of the blast-furnace they came, and arranged themselves about the cinder notch, and on the girders above. The men and their bosses came. There was the labor foreman, and the foreman of all the carpenters, of all the window-glass fixers, all the blowers, the electricians, the master mechanic. Then came the superintendent of the open-hearth and Bessemer, Mr. ”

“ The want of care in regulating the dampers of the airbox often makes a house cold, however great the furnace181 fire. A strong wind requires the dampers nearly closed, especially when it is on the side where the air enters from without. Every furnace should be supplied, not by cellar air, but by air taken through a shaft from a height, and so more pure.
Remember that an open fire, or an opening into a hot-air flue, will ventilate properly in all seasons and all weathers. ”

“ Small articles are readily fired in a Fletcher's crucible furnace supplied with a gas blow-pipe; the furnace is heated gradually to begin with. When a dull red heat is attained, the full power of the blast may be turned on, and the furnace kept at its maximum temperature for three or four hours at least, though on an emergency shorter periods may be made to do. ”

“ 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 ”

“ We may mention here that it has, in more recent times, when very high temperatures are obtainable, been found unnecessary to cause even the flame to come into contact with the substances on the hearth, inasmuch as the heat radiated from the flame and the intensely heated roof of the furnace suffices, so that in consequence of this the roofs are now constructed nearly flat. In the puddling furnace the melted metal is constantly stirred, and no little skill is required to regulate the fire by the damper on the chimney, and to admit the proper amount of air to mix with the flame. ”

“ A puddling furnace is a long, narrow, maw-like chamber of brick and fire clay with a depressed floor for the molten iron to lie in and a small square door at the end. It is heated to inferno by a cataract of flame rising from a fire pit at one side and sucked by draught [102] across the roof of its mouth. When the whole interior is like a dragon’s gullet, white hot, wicked and devouring, cold pigs of iron are cast in, the door is banged to, the chinks are stopped and the puddler gathers up his strength. ”

“ The heat that the worker about these furnaces must face may be divided in general into two classes: there is first that heat due to the flame and hot gases that the blast in the furnaces forces out onto a man's body and face. In the majority of furnaces Page 193 this is by far the most discomforting, and care must be taken to fend it and turn it behind a suitable shield. The second class is the radiant heat, discharged as light from the glowing interior of the furnace. ”

“ A roaring fire will sometimes set fire to the soot in the chimney, or carry burning sparks to the roof of the house.
The stove should be set at least eighteen inches away from the woodwork, and the floor beneath it should be covered with brick, tiles, or a sheet of metal.
Never leave the house, or go to bed, when the drafts of the stove or furnace are open. Overheated furnaces have caused many serious fires in the night. Even a low fire will sometimes burn up unexpectedly, especially if the wind blows hard enough to create a strong draft. ”

“ Furnaces are constructed according to many different patterns with varying degrees of complexity in arrangement; but all may be considered as combining three essential parts, namely, the fire-place in which the fuel is consumed, the heated chamber, laboratory, hearth or working bed, as it is variously called, where the heat is applied to the special work for which the furnace is designed, and the apparatus for producing rapid combustion by the supply of air under pressure to the fire. ”

“ Owing to the great danger from fire incident to burning charcoal or sulphur in open pans, a special furnace provided with means for forcing the gas into the compartments of vessels or buildings is generally employed. ”

“ When the furnace is filled with coals and kindled, if the door of the ash-hole be set wide open, and that of the fire-place shut very close, the force of the fire is increased; and if, moreover, the pyramidal cover be put on the top, and the conical funnel added to it, the fire will become still more fierce. ”

“ 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. ”

“ In small fire-boxes, only small quantities of fuel can be burned at once, and in consequence, fresh firing is continually required, which interferes greatly with the work of the furnace and decreases the rapidity of heating. Each addition of cold fuel has a cooling effect on the fire and furnace gases, the temperature in the hearth being found to drop for a period of five or ten minutes by as much as 100° C., the flame becoming smoky, red, and cold. ”

“ 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. ”

“ Nothing could stand such terrific heat. The rafters of the building began to burn. To quench the fire in the usual way was impossible, for had any cold fluid come in contact with the liquid metal, the consequences would have been frightful: the furnace would have been destroyed, and the 400 cwt. of bronze lost. With wet cloths, therefore, the burning rafters were covered to smother the flames. But the walls were glowing, too; the whole building was now like a vast furnace. Yet still more fuel on the fire!—the heat is not enough; the metal boils not yet! ”

“ For the spirits seen walking about in the fiery furnace, which was heated seven times hotter than its wont, for the especial grilling of Messieurs Shadrach, Meshach and Abednego, bade defiance to fire;—a fatal fact against the theory of a physical hell—the spirits proving not only water, ice, and wind, but fire-proof also! ”

“ 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." ”

“ Four hours in the boiling fiery furnace which the Terra Nova's stokehold formed in the tropics, unless there was a good wind to blow down the one canvas shaft, was a real test of staying power, and the actual shovelling of the coal into the furnaces, one after the other, was as child's play to handling the 'devil,' as the weighty instrument used for breaking up the clinker and shaping the fire was called. ”

“ There is certainly a satisfaction in the direct radiance of a hickory fire which is not to be found in the fieriest blasts of a furnace. The hot air of a furnace is a sirocco; the heat of a wood-fire is only intense sunshine, like that bottled in Lacrimae Christi. ”

“ When exposed by itself to the fire, either in grains or in larger pieces, it is of extreme difficult fusion, and hath been kept for two hours in an air furnace in a heat that would run down cast-iron in fifteen minutes: which great heat it hath endured without being melted or wasted ”

“ 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. ”

“ 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. ”

“ For the deficiency of heat, or the failure of some of the hot-air pipes of hot-air furnaces in certain winds and weathers in large houses or specially exposed rooms, the best addendum is an open fire-grate. With this provision in northerly rooms, to be used occasionally, hot-air furnaces may be made to produce all the advantages of steam heat in even the largest dwelling-houses. ”

“ The burners should be so located that the flames from individual burners do not interfere nor impinge to any extent on the side walls of the furnace, an even distribution of heat being secured in this manner. ”

“ I have learned, of late, from men of experience in these matters, why it is desirable to continue the heat—it is because no furnace can be heated up for two or three weeks, and then blow out, or stop, without risk of spoiling the furnace, or destroying its lining; and it frequently so injures the furnace, that it has to be rebuilt, or at least a portion of it. Hence, when it costs from one to five thousand dollars to prepare a furnace to bear a long blast, it is a great loss to any company to have it blow out in a short time. ”