US795245A - Slag-heated boiler. - Google Patents

Description

PATENTED JULY 18,1906:

R BAGGALEY. SLAG HEATED BOILER. APPLIUATION FILED MAY 4.1904.

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WITNESSES mvamon Q11, A! JF T PATENTED JULY 18, 1905. R. BAGGALEY. SLAG HEATED BOILER.

APPLICATION FILED MAY 4.1904.

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% INVENTOR WITNESSES NITED STATES Patented July 18, 1905.

RALPH BAGGALEY, OF PITTSBURG, PENNSYLVANIA.

SLAG-HEATED BOILER.

SPECIFICATION forming part of Letters Patent N0. 795,245, dated July 18, 1905.

Application filed May 4, 1904. Serial No. 206,322.

To all whom it may concern:

Be it known that I, RALPH BAGGALEY, of Pittsburg,in the county of Allegheny and State of Pennsylvania, have invented a new and useful Slag-Heated Boiler, of which the following is a full, clear, and exact description, reference being had to the accompanying drawings, in which Figure 1 is a rear view in section of the boiler, steam-drum, cracked-slag vault or pit, and mud-drum, with the supporting-frame for the apparatus in elevation. Fig. 2 is a vertical section on the line II II of Fig. 1. Fig. 8 is a top plan view.

The object of my invention is to utilize successfully the waste heat of slags, and particularly those slags that result from the smelting of copper ores, and without necessity for use of moving mechanism of any kind.

Molten slag is corrosive and injurious to all metals. hen it comes in contact with water-jacketed surfaces or heavy metal or walls of some refractory materials, it instantly forms skulls which constitute separating-partitions between the body of molten material and the walls. Such slag skull is well known to be a non-conductor of heat, and for this reason it is most difficult to transmit heat from a body of molten slag through such a skullto a boiler, so as to produce efiective steam pressures. Efforts have been made in the past to deliver bodies of molten slag varying from eighteen inches to six feet in diameter into the interior of large boiler-tubes in the hope that the heat would be transmitted quickly enough to the water of the boiler to generate steam for commercial purposes. It was found, however, that almost in an instant a skull was formed completely around the body of molten slag and that thereafter the travel of heat from the molten body into the water was so slow as to render the effective generation of steam nearly, if not quite, impossible. In any event no one has so far been able to force molten slags to deliver up their waste heat in the generation of steam-power for commercial purposes, as before stated. Another difficulty encountered by such experimenters was due to the excessive shrinkage of slag in cooling and solidifying. This shrinkage is believed to be at the rate of one-quarter of an inch to the foot and sometimes it may be more than this. The shrinkage of cast-iron in cooling rarely exceeds one-eighth of an inch to the foot. As a result of this excessive shrinkage it has been found that where molten slag has been run into tubes or cylinders the outside surfacein contact with the boiler congeals almost instantly and by shrinking separates the slag column from the boiler-tube and renders actual contact between the two impossible. The separation of contact interposes a heat-insulating layer of air between the slag and the tube and further prevents the transmission of heat to the water. In the light of this explanation it will be seen that the heat of the molten slag is compelled, in order to reach the water of the boiler, to pass first through the constantlythickening non-conducting skull of molten slag and thereafter through the non-conducting film or layer of air which is also constantly increasing as shrinkage progresses.

The difliculties above mentioned are in a large measure overcome by the apparatus described in my PatentNo. 725,392, dated April 14:, 1903, or my Patent No. 746,235, dated December 8, 1903, because in the apparatus described in those patents especial provision is made for the delivery of the slag into very small tubes. In the first of these patents, which describes a rotary boiler, no matter to what extent the slender slag column may contract it is forced by gravity to settle down into the receptacle and to continue in actual contact with the tube on all sides and throughout its entire length. The entire spindle or column of molten slag is caused to solidify and the formation of skull is impossible. In the second patent above mentioned the slag is also delivered in molten form into such slender tubes that it is forced to solidify and is forced to yield up its heat to the water of the boiler, for the simple reason that the heat cannot go any place else, inasmuch as the boilertubes are sealed below by the congealed slag and are effectually sealed above by the constantly-entering molten slag. Hence no aircurrent that might exercise a chilling effect within the tube is possible and no body of molten slag can remain in the tube, because it is too slender in cross-section to permit this. An objection that I have found to both of these inventions is that to operate them requires machinery and power and a certain amount of expense.

My present invention is intended to overcome the peculiarities of slag which have been mentioned and to render it possible to operate a slag-boiler without the use of machinery or power of any kind.

As shown in the drawings, the slag-boiler consists of cylindrical sections 2 3 4E, preferably three in number, hung concentrically within each other from a large steam-drum and around a central tube 5. They are so spaced that the molten slag when delivered to the boiler must be delivered within the three annular slag-spaces a 5 0 thus afforded, and on congealing within the said spaces is forced to assume the form of three concentric slag-pipes. The slag-spaces are designed with such narrow cross-section that the entire body of slag within each space will be forced to congeal. No body of molten slag can remain inside of them and no skulls can be formed in contact with the boiler-plates at any point. Each of the three circular spaces is so arranged also that its lower end is nearly twice as broad as the upper end, and the slag in its passage downward therefore finds a ready and constantly-increasing relief in its efforts to secure an exit by gravity. The arrangement of the slag-spaces in the form of circular tubes is important. The express purpose is to make use of the great shrinkage incident to the congealing of slag for the purpose of automatically holding the hot slag firmly in contact with each inner circle and also as a means of fracturing it, so that when fractured it is forced by gravity and by the flare of the slag-spaces below to pass out freely and automatically from the boiler. I utilize the great shrinkage of slag while in the act of congealing to fracture and free itself within the tube, so that when thus fractured it will be forced to fall into the closed vault 6 below. The floor of this vault is preferably arranged at an angle of, say, fortyfive degrees, and its bottom is provided with a lining that will not offer much friction to the sliding slag. Its lower portion may terminate in a tube or spout 7, provided with a door or gate 8 at its lower end and a lever 8 or other suitable means for actuating the door. This slag-vault should be closed and as nearly airtight as practicable, so that no currents of air can pass through the body of cracked slag within it and thereafter through the tubes. The body of cracked slag within the vault will still be hot enough after it has fallen from the tubes to exert a distinct heating effect over the entire bottom of the boiler. If

the operator opens this gate 8, the cracked slag of necessity must slide out. This will lower the accumulation of slag in the vault and in each circular slag-space. By this arrangement the operation of the entire boiler can be controlled at will and without the use of machinery. For instance, by means of the hand-lever (shown in Fig. 2) or equivalent worm or cog gear the gate may be set at any desired degree of opening and the rate of discharge of the cracked slag may be exactly related to the entrance of molten slag above. Should there be a stoppage or interruption to the natural descent of the slag by gravity, I may discharge water from jets 9, Fig. 1, in the cracked -slag vault against the slag in the tubes at the base of the boiler. This will crack it and cause its descent by gravity to be instantly resumed. These water-jets may be provided in any number and in any form. as may be found necessary.

The boiler should be provided with a large steam-drum 10 above, in which the waterlevel is preferably maintained up to the center line of the same, a water-gage glass 11, Fig. 1, being provided to insure the permanency of the water-level while the boiler is in operation. This water-level should be above the top of the boiler-shelf itself in order to effectually prevent the entering molten slag from burning the material of which the boiler is composed.

The three cylindrical sections and the central column or tube of which the boiler is composed are connected directly at the top with the steam-drum by pipes or nipples 12 and are connected directly below with a muddrum 13. In this manner I secure a continuous circulation of the water throughout each sect-ion of the boiler. I also provide a boiler in which the precipitated scale will settle by gravity into the mud-drum, whence it can be removed from time to time, as desired.

By the term annular slag-space herein. used I do not intend to limit myself to slagspaces which are circular in cross-section, as their shape may be modified. They may also be used in any suitable numberone or more as may be desired, for the construc tion of the particular boiler.

Many modifications and changes in the de tails of this apparatus will be suggested by the foregoing description to those skilled in the art without departing from the spirit of my invention.

I claim 1. A slag-heated boiler having an annular slag-space; substantially as described.

2. A slag-heated boiler having an annular slag-space flaring downwardly; substantially as described.

3. A slag-heated boiler having a plurality of annular slag-spaces, one within the other; substantially as described.

4:. A slag-heated boiler having a plurality and a plurality of annular Water-spaces, a steam and Water drum with which the Waterspaces are connected, and a mud-drum; substantially as described.

In testimony whereof I have hereunto set my hand.

RALPH BAGGALEY.

Witnesses: I

J. C. WVOLFRAM, W. D. KYLE.

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