US2664284A

US2664284A - Slag removal

Info

Publication number: US2664284A
Application number: US124441A
Authority: US
Inventors: Robert A Fausnaught
Original assignee: HAWS REFRACTORIES Co
Current assignee: HAWS REFRACTORIES Co
Priority date: 1949-10-29
Filing date: 1949-10-29
Publication date: 1953-12-29
Anticipated expiration: 1970-12-29

Description

A. FAUSNAUGHT SLAG REMOVAL Dec. 29, 1953 Filed Oct. 29, 1949 2 Sheets-Sheet 1 INVENTOR ROBERT A. FAUSA/AUGHT IQ M 9 55 ATTORNEYS Dec. 29, 1953 R. A. FAUSNAUGHT 2,664,284

SLAG REMOVAL Filed Oct. 29, 1949 2 Sheets-Sheet 2 1N VENTOR ROBERT A. FAUS/VAUGHT ATTORNEY! Patented Dec. 29, 1953 UNITE sum REMOVAL Application-OctoberZS, 1949,=S'erial No. 124,441

5!. Claim. 1

This invention deals with the problem of removing slag from the slag pocket of an .openhearth furnace, and relates, more specifically, to a novel form of refractory tile which is used to facilitate breaking up the-slag in-the slag pocket by a blasting operation.

Open-hearth furnaces are provided with slag pockets at their ends in which slag carried out of the furnace by the products ofco-mbustion-may collect. These slag pockets are located between an end of the furnace and the regenerator structure employed to transfer heat to and from the gas flowing throughthe furnace. When the flow of gas through the furnace is reversed, the slag in the slag pockets is chilled and solidified. This slag is extremely hard and builds up in a heavy layer as the refining operationcontinues. At the end of the furnace campaign, it is necessary to remove this layer of slag from the slag pockets at each end of the furnace. The conventional practice of removing slag invloves the use of :air hammers which are employed to break up the slag layer prior to its removal. It ha also been proposed to drill holes in the slag and blast it prior to removal, but due to thehardness of the slag, it is very difiicult to drill the blasting holes, and extreme wear on the drilling equipment is encountered. In addition, all conventional methods of removing slag necessitate a cooling down period until the temperature of the slag is reduced to apointat which workmenmay enter the slag pocket.

One of the principal objects of thi invention is the provision of improvements in the art of slag removal which will enable the slag removal operation to "be started without Waiting for its temperature to drop to a point at which workmen can enter the slag pocket .of an open-hearth furnace.

A furtherobject of this invention is to provide an open-hearth furnace with structure which will provide an explosive charge receiving chamber embedded in the slag in the slag pocket of an open-hearth furnace after slag collects in isllch slag pocket.

.A still further object of this invention is to provide a brick-shaped refractory tile having an opening extending longitudinally therethrpugh to form an exp o ive ar e receiv n opening which may be mounted in position in the lease of a slag pocket of an open-hearth furnace.

A still further object of the invention is to provide a slag pocket of an open-hearth furnace with a refractory tube in which an explosive charge may be placed for the purpose of blasting 2 loose the vslag collected in the slag pocket rat the endo'f 'thecampaign'of thefurnace.

To the above and related :ends, this invention contemplates the provision of hollow refractory tiles which :are mounted in the base of a p hearth slag pocketito form 'a refractory tubeprior to "the beginning of a'furnace campaign. During the furnace campaign, the slag collects over the refractory tube in a "hard dense layer. At the endof the furnacecampaigm'an explosive charge is inserted in the tube and is-detonated to rupture the refractory tube and break '-up the layer of slag collected thereover. The broken up slag may then be readily removed from the furnace without the'tedious digging operation with an air hammer heretofore required for this purpose, and without waiting for the slag to cool-down.

'Other objects and advantages of the invention w ill become apparent from the following description.

the drawings, there is shown a preferred embodiment-of the invention. In this showing:

Fig. 1 a itragmentary vertical sectional view through the slag pocket of an open-hearth furnace showing the arrangement of a refractory tube positioned therein in accordance with the principlesof this'invention;

Fig. 1-2 'is a fragmentary sectional view taken substantially along "the line I III ofFig. '-1;

'3 *is a fragmentary sectional view taken substantially along the line 'III-II-I of Fig. 1;

Fig. 4 is aside elevational view of one of the refractory tiles used td-make the refractory tubes of Figs. '1 "through 3-; and

Fig. 5 is *an end elevational view looking from the right of Fig.4.

In the drawings, the numeral I designates an open-hearth furnace having a hearth 2 in which the bath of 'metal to be refined is contained. Each end of the furnac *2 is connected in the usual manner by vertically and downwardly ex tending gas and air ports to a slag pocket indicated as "a whole by the numeral 3. As is welllrnown, the slag pockets 3 are positioned between the open hea-r'th 2 and the reg-eneratcr structures of the Open-hearth furnace and operate to collect the slag from the gases being exhausted from the open-hearth 2. This slag collects on the base -4 of the slag pocket 3 in a hard dense layer which must be dug out at "the end of each turnaoe'campaign.

"In order to facilitate the removal of slag from the slag pocket, one or more refractory tubes 5 are mounted in a position in which the slag will collect thereover in a'denseiayer. Theref'ractory tubes 5 may be mounted directly on the base 4 of the furnace or may be mounted on brick supporting walls 6 in positions spaced at a slight elevation with respect to the base 4 of the slag pocket. The tubes 5 are provided with an opening '1 extending longitudinally thereof for a purpo e to be described.

The tubes 5 are each formed of a plural ty of refractory tiles 8 which are placed in end-to-end position, as best shown in Figs. 2 and 3. As best shown in Figs. 4 and 5, the tiles 9 have a rectangular contour and are generally brickshaped. A cyl ndrical opening 9 extends between opposite end faces l and H of. each tile 8. The end face In is provided with an annular projection l2 about one end of the opening 9, and the end face H is provided with an annular recess [3 about the other end of the opening 9. As best shown in Fig. 3, the tiles 8 are placed in end-to-end position with the end faces H] and II of adjacent t les in abutting engagement, and with an annular projection l2 nesting in a recess 13. The manner in which the projections l2 fit in the recesses [3 provides an interlock preventing movement of the tiles 8 relative to each other and the tube 5 of which they form a part and prevents seepage of the slag into the openings 1. The tiles 8 are formed from any suitable refractory mater-a1 such as commonly used in the formation of the brick for the openhearth walls, and which will withstand the temperature of the molten slag without melting. It will be noted that the center of the opening 9 is spaced downwardly from the center of the tile 8 in order that the tile 8 will have a greater protective mass above the opening 9 where protection is most needed.

In operation, the tiles 8 are placed in end-toend position to form a tube 5 either on the base 4 of the slag pocket or on an elevated support 6 prior to starting the furnace campaign. At the end of the tube 5, the wall M of the furnace is provided with an opening 15 through which access may be had to the tube opening 1. During the furnace campaign, the openings 15 are plugged as by the removable bricks indicated at 1'6 in Fig. 2. At the end of the campaign, the bricks l6 are removed and cans H of explosive may be charged into the opening 5. The end can of explosive I7 is connected to a detonating circuit It having a switch I9 operable upon closure to detonate the explosive charges [1.

In practicing the invention, it has been found desirable to use a slow burning explosive for the charges IT. For this purpose, an explosive known to the trade as nitro-carbo-nitrate and which is sold under the trade name Nitro-Mon has been found particularly suitable for the purposes of this invention. A slow burning explosive is desirable since it will lift the slag cover and break it up without damage to the furnace structure. The entire length of the tube lneed not be filled with explosive, but only an amount sufficient to break up the slag need be used. Moreover, it will be apparent that the entire length of the tube 5 need not be blown at one time. In place of blowing the entire length of the tube 5, it may be blown in sections. For this purpose, several cans I! of explosive may be moved to one end of the tube 5 and blocked off with mud with the leads 29 of the end can extending out through the opening [5 for connection in the circuit l8. Upon closure of the switch l9 to energize the leads 26 from the battery 2 I, a section of the tube 5 will be blown to break up a portion of the slag cover in the slag pocket 3. After such port on of the slag cover has been removed, an additional charge may be inserted in the tube 5 to blow another section thereof and break up still more of the slag cover in the slag pocket. In many cases, it will be found more desirable to break up the slag cover in sections rather than to break up the slag cover in one operation by blowing the entire length of the tube 5.

From the foregoing, it will be noted that the tiles 8 of this invention provide a novel form of refractory tube in the slag pocket of an openhearth furnace which can be mounted in position prior to the collection of a layer of slag thereover and which thereby furnishes an explosive charge receiving compartment pre-formed in the slag which collects in the slag pocket. Attention is particularly directed to the fact that the provision of the refractory tube 5 facilitates the removal of slag from an open-hearth furnace by a blasting operation. To effect such removal it is merely necessary, at the end of a furnace campaign, to insert an explosive charge in the tube 5 and detonate the charge by operation of the switch 19 located outside the furnace. Attention is particularly invited to the fact that the explosive charge may be placed in position, and the blasting operation completed while the slag is too hot to permit workmen to enter the slag pocket. In this manner, the slag cover may be broken up without the cooling down period heretofore required for conventional slag removal operations. It will thus be seen that the refractory tube 5 not only facilitate the placing of an explosive charge in an operative position under solidified slag, but also reduce the t'me required to effect slag removal by eliminating the cooling down period heretofore required.

While I have illustrated and described one specific embodiment of my invention, it will be understood that this is merely by way of illustration, and that various changes and modifications may be made therein within the contemplation of my invention and under the scope of the following claim.

I claim:

A method of breaking slag formations on the floor of an open-hearth ash pit which comprises constructing a hollow refractory tube on the floor of the pit and in a position to be covered by the slag as it collects in the pit, inserting a charge of explosive in the tube after it is covered by a body of slag, and detonating the explosive charge to thereby fracture the tube and the overlying body of slag.

ROBERT A. FAUSNAUGHT.

References Cited in the file of this patent UNITED STATES PATENTS OTHER REFERENCES Pages 1099, 1100 of Blast Furnace and Steel Plant of October 1937.