US 2840365 A
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June 24, 1958 G. KRUKY 2,840,365
\METHOD OF BREAKING FORMATION OF SOLID DEPOSITS Filed June 7, 1955 2 Sheets-Sheet 1 G. KRUK June 24, 1958 METHOD OF BREAKING FORMATION OF SOLID DEPOSITS 2 Sheets-Sheet 2 Filed June 7, 1955 IIIII'IIIIII'III|||'I. lllllllzl ll|||'| "l llllllr'lilr Ufl w tes P n METHOD OF BREAKING FORMATION on SOLID DEPOSITS Geri-it Krulr, Heiloo, Netherlands, assignor to N. V.
Springit, .Zandvoort, Netherlands, a Dutch limited-liability company Application June 7, 1955, Serial No. 513,847
Claims priority, application Netherlands June 11, 1954 7 Claims. (Cl. 263-45) This invention relates to a method of breaking formations of solid deposits formed in a hot space such as an oven or a slag pocket for an oven, e. g. a slag pocket of an open hearth.
It has been proposed to break the slag in a slag pocket of an open hearth furnace in the following manner. In the pocket brick supporting walls are built, upon which refractory tiles are arranged in a continuous row having a hole through them. Between such supporting walls rows of tiles can be arranged on the bottom of the pocket. The holes in the tiles constitute a continuous channel in which, for breaking the slag, explosives can be inserted and exploded. The brick walls for supporting the tiles have to be rebuilt after explosion, the tubes and the walls are expensive and take up a considerable part of the efficient space in the pocket. The slag will tend to arch between the walls so that the useful space is further reduced.
The insertion of the explosive is quite dangerous because the explosive tends to self-detonation, therefore there should be a delay until the slag body has cooled sufliciently.
-It is an object of the present invention to prevent loss of time and expense in breaking such deposits.
'It is a further important object of this invention to prevent the oven, furnace or the like to be taken out of operation for too long a time, which has an important effect upon production capacity.
It is a further object of this invention to remove the deposits in a safe way.
The invention is mainly distinguished from the known method of slag removal in that one or more simple unitary tubes are inserted before or during operation of the furnace or the like, such tubes being cooled by the passage of a cooling fluid such as water therethrough during operation and said tubes being exploded immediately after stopping the cooling at the end of the operation of the furnace or the like. I
In the drawings a preferred embodiment of a slag pocket for application of the method of the invention has been shown and said embodiment will now be described below.
Fig. 1 is a diagrammatic cross-section of a slag pocket of an open hearth furnace for applying the present invention.
Fig. 2 is a front view of said slag pocket.
Fig. 3 is a cross-section of one of the tubes with connections for the cooling fiuid according to 'this'invention as applicable to slag pockets according to Figs. 1 and 2.
The open hearth furnace is not shown in the drawings. It is positioned above the part of the plant shown in Figs. 1 and 2. in well known manner this furnace has a hearth containing a bath of metal to be refined. At each end of said hearth there are two vertical ducts: (1) Each leading to a slag pocket 2 of which one only is shown. (2) The gases flowing downwards from the duct 1 to the slag pocket 2 thereafter pass through a passage 3 to the regenerators of well known structure which are not shown in the drawings. Said hot gases heat up the filling of the regenerators and after some time the flow of gases is reversed, air and fuel gas flowing in parallel through separate hot regenerators and through passage 3 upwards through duct 1 of each regenerator towards the hearth. Usually there are four regenerators and also four ducts 1 and four slag pockets 2. Two of said parts are arranged to one side of the furnace below the hearth and the other two at the other end of the furnace. Gas and air mix in the hearth and give combustion, flow over the molten metal in the bath of the hearth and descend at theopposite side 'of the hearth through both ducts 1 at that side to the corresponding slag pockets 2 and regenerators to heat up said regenerators.
The slag particles entrained by the gases form deposits in the slag pocket as shown in Fig. 1, and with a dotted line in Fig. 2. The line in the drawing gives about the highest level to which the deposits are allowed to collect. Thereafter these deposits should be removed. They constitute a very hard and solid hot mass. The shape of said line may differ considerably even in the same plant, between different operation periods.
According to the invention unitary tubes 4 are inserted in the slag pockets to break up the deposits. Said tubes are preferably simple metal tubes. They are inserted before the deposits begin to form or before they are formed sufficiently to cover the points where one wishes to insert the tubes. I
The tubes 4 may be introduced by sliding them through suitable openings in the front wall 5 of the slag pocket. Said wall consists of bricks and it is possible to provide scalable holes in several bricks for allowing the tubes 4 to be inserted, or it is possible to remove the bricks during operation of the furnace so that a hole is formed through which the tube may be inserted, the hole around the tube beingsealed thereafter by some suitable material. At the beginning of the operation of the furnace the lower tubes 4 are inserted. Fig, 2 shows three of such lower tubes. Thereafter, as the deposits collect further, which is controlled by looking through one or more inspection openings in the slag pocket wall, and as the deposits have reached a certain level a tube 4 is inserted right above the momentary surface of the deposits. When the deposits have filled the slag pocket fully so that breaking and removing of the deposits becomes necessary there are for instance six tubes 4 in the pocket at different levels as shown in Fig. 2 in places dependent on the shape of the slag surface.
It is possible to support the tubes 4 at the back end of the pocket upon supports 6 made in the pocket for the purpose, e. g. by a stepped shape of the back wall thereof, but it is also possible to support the tubes at the front end in front of and in the wall 5 only. It is also possible to have at least the higher tubes 4 rest immediately upon the deposits already formed when inserting the tubes.
' If the surface of the deposits has a shape different from the shape of the drawings the tubes4 could be introduced tube 4 has a flange 1% connected by bolts 11 to a cover open hearth furnaces.
The tubes 4 are inserted as a whole in the condition shown in Fig. 3, with the inner pipe 13 arranged therein. Through hose 15 water is fed to pipe 13, said water flowing to the open end 19 of said pipe and back through the space between pipes 4 and 13 to the outlet 8. Fig. 2 shows that the hoses 9 and 15 are connected to horizontal ducts 20 and 21 respectively leading along the upper part of the outside ofthe slag pocket, the duct 21 feeding cooling water to the hoses 15 and the duct 20 discharging said cooling water again. Evidently if there is a shortage of water it ispossible to have the water move in a closed circuit with a cooling heat exchanger or cooling tower in the circuit. 7
The flow of the cooling fluid needs only be so that the pipes 4 are prevented from burning and of course it is in general preferable to prevent boiling of the water.
If the slag has to be broken the pipes 4 are drained through the drains 16 by opening cock 17 and the hoses 9 and 15 are loosened. Thereafter the bolts 11 are loosened and the flange 12 with the inner pipe 13 is removed from the pipe 4. Explosive charges are now inserted, for instance, in the form of a pipe filled with explosive and closed at both ends with only leads through one end for detonation. Such a pipe could slide into any pipe 4 immediately after termination of the cooling so that no danger of self-detonation exists, because the explosive charges cannot become too hot before being exploded intentionally.
After explosion which may take place while the slag body is still too hot to allow personnel to work therein, the loosened slag has to be removed. This is accomplished by dismantling the front wall so that good access to the space is obtained. No waiting for further cooling of the slag is necessary and it is possible to begin the removing of the slag immediately after the explosion and the dismantling of the front wall For removing the loosened slag itself the personnel does not need to work in the space during a too long time, and moreover the space cools rapidly after dismantling the front wall 5. The exploding of the tubes will preferably not take place all at the same moment, but the higher tubes will preferably be exploded first, either one by one or in While I have illustrated and described hereinbefore' one specific embodiment of my invention, it will be clear that thisis only by way of illustration. Various changes and modifications may be made therein, and this invention is in its application not restricted to slag pockets of Such changes and modifications do, however, always fall within the scope of the appendant claims.
What I claim is:
l. A method of breaking formations of solid deposits formed in a hot space such as an oven or a slagpocket for an oven, comprising introducing a tube into said space during the formation of the deposits in said space in the region of said space Where such deposits are formed in operation, leading a cooling fluid through said tube during the formation of deposits in said space to preserve said tube, inserting an explosive into said tube after the forming of the deposits and detonating said explosive in the furnace to break the tube and the deposits surround ing it. e
2. A method of breaking formations of solid deposits formed in a hot space such ,as an ovenor a slag pocket for an oven, comprising introducing a metal tube into said space during the formation of the deposits in said space in the region of said space where such deposits are formed in operation, leading a cooling fluid through said tube during the formation of deposits in said space to preserve said tube, inserting explosive into said tube after the forming of the deposits and detonating said explosive to break the tube and the deposits surrounding it.
3. A method of breaking formations of solid deposits formed in a hot space, such as an oven or a slag pocket for an oven, comprising introducing a plurality of tubes into such a space, a part thereof being introduced at the beginning of the operation of the said space close to the bottom thereof and other tubes being introduced during operation after partial formation of the deposits at positions immediately above the temporary upper surface of the deposits, leading a cooling fluid through said tubes to preserve the same, inserting explosive into said tubes after the complete forming of the deposits and detonating said explosive to break the tubes and the deposits surrounding it.
4. A method of'breaking formations of solid deposits formed in a hot space, such as an oven or a slag pocket of an open hearth-furnace, comprising introducing a first tube and a second tube of smaller diameter within said first tube into said space before the formation and completion of formation of the deposits in said space in the region of said space 'where such deposits are formed in operation, leading a cooling fluid through one of said concentric tubes and back through the other in operation of said space to preserve said tubes, the outer tube being closed at one end, inserting explosive into said first tube after the forming of the deposits and detonating said explosive to break the tube and the deposits surrounding it.
5. A method of breaking formations of solid deposits formed in a hot space, such as an oven or a slag pocket for an oven, comprising introducing a first tube into said space in the region of said space where. deposits are formed during operation, leading a cooling fluid through said tube in operation'of said space to preserve said tube, inserting a tube with an explosive slidingly into said first tube after the forming of the deposits,- sealing said explosive containing tube at both ends, and detonating said explosive to break the tube and the deposits surrounding it.
6. A slag pocket device for a furnace or a similar hot space, in which during operation solid deposits are formed which have to be re rnoved at intervals, said pocket comprising a wall, a number of selectively operable and sealable passages in said wall, unitary tubes insertable through said passages, by sliding into said pocket, means for feeding acooling fluid tosaid tubes and means for inserting an explosive into said tubes and for detonating said expl si r 7. A device as claimed in claim 6 comprising a plurality of unitary tubes adapted to he slid into said slag pocket in which solid deposits are formed in operation, said device further comprising means to feed a cooling fluid to each of said tubesand means to explode each of said tubes.
References Cited in the file of this patent UNITED STATES PATENTS 2,151,264 Cavanaugh Mar. 21, 1939 2,299,892 Gerwig Oct. 27, 1942 2,664,284 'Fausnaught Dec. 29, 1953