US2102257A - Furnace construction - Google Patents

Description

Dec. 14, 1937'. G. l.. DANFoRTH, JR

FURNACE CONSTRUCTION Filed Aug. 21, 1936 N l f BN also in View of Patented Dec. 14, 1937 UNITED STATES 2,102,257 FURNAOE CONSTRUCTION George L. Danforth, Jr., Chicago, Ill., assignor to' Open Hearth Combustion Company, Chicago, Ill., a corporation of Delaware Application August 21, 1936, Serial No. 97,165 2 claims. (o1. 263-46) This invention relates to a new and improved furnace construction and more particularly to a door construction adapted for use in .open hearth furnaces or the like.

Furnaces have heretofore been developed in which the rear walls have been sloped upon angles approximating the angle of repose of bottom-making materials so that these walls may be fully protected by such materials. The sloping of the front walls of furnaces has presented different problems in view of the necessity of having charging doors in such walls and the usual close proximity to such walls of tracks carrying the charging machines.

The charging doors are Operated vertically and it is not practical to operate such 4doors on walls sloping upwardly and outwardly even if the necessary clearance were available. In practice door frames or guides slope inwardly 'to some extent as they go upwardly so that the weight of the door causes it to lie against thel` guides 'to assist in maintaining a gas-tight. closure.

Furthermore, with lusual types of doors there is little advantage in sloping the front wall outwardly unless the slope can be maintained 'at the sides of the doors so as to fully cover the door jambs. It is not practical to maintain the usual types of bottom -steep slopes or upon vertical walls. Consequently it is impractical to cover the jamb at the top of the door asl well as 'at t e bottom unless the material slopes inwardly and blocks a portion of the doorway. If this were done in' usual types of doors, the material which extended into the f doorway beyond the jamb Would be destroyed by the charging boxes in charging the furnace. Actually with these doors having the same width at the top and bottom, it is necessary to face the side of the doors with brickwork. This brickwork soon burns away, however, andV it is customary then to some extent to build up the face of the brickwork with a plastic material. If the foundation for this material extends between the face of the door frame and the center line of the doorway in Order to provide some slight slope, the foundation is exposed and destroyed by the charging operation. If the foundation is kept behind or in line with the frame leg, theY material will crumble 'down and form a slope, thereby exposing a large amount of frame surface which isgenerally Water cooled and which when exposed is chilling to the furnace temperature. If the frame be not water cooled it will be destroyed by the heat of the furnace.

materials upon extremely It is also desirable that the furnace door openpossible. After the furnace is charged with all the cold stock required, a bank of refractory ma-v terial six to twelve inches high is placed on the bottom of the doorway at the floor plate level before the hot material is poured into the fur-l nace. The lining of the door burns out considerably more in the lower half than in the upper half, this being due to the action of basic elements of the bath being greater at the lower elevation. A narrow opening in the lower portion ofthe .door frame minimizes the exposed surface of the door lining.

-It is an object of the present invention to provide a new and improved furnace door construction.

It is also an object to provide a. construction which permits sloping or offset front walls.

It is an additional object to provide a construction which includes a thicker front wall sloping inwardly toward the hearth and also sloping inwardly toward the bottom of -the door openings.

It is a further object to provide a construction permitting larger top opening and smaller bottom opening of the door than is customary.

It is also an object to provide a door con-l struction which reduces exposure of water cooled surfaces by maintaining the inside lining and lengthensthe life of the brick arches over the doors by maintaining the supporting jambs.

It is an additional object to provide a construction which requires less banking .of doors, presents less opportunity for metal breakouts, and which reduces the wearand'upkeep of the door lining.

An additional object is to providean improved door frame for metallurgical furnaces well,

adapted to meet the needs of ation.

commercial oper- An additional object is to provide an improved' door frame having a shape conforming to the improved type of furnace walls referred to h'ereinabove.

Other and further objects will appear as the description proceeds.

I have shown a preferred embodiment of my invention in the accompanying drawing, in'

which- Figure 1 is a fragmentary elevation showing a furnace door;

Figure 2 is a transverse vertical section taken on line 2--2 of Figure 1; and

Figure 3 is a horizontal section taken on line 3-3 of Figure 1. f

In the drawing, the hearth portion of the furnace comprises the brickwork sections II and I2 and the usual bottom material I 3 which is put in in, loose form. The lower metal framework I4 of the furnace front wall has connected thereto the buckstays I5 which are oiset and have vertically extending upper portions I6 to which are secured the channels II supporting the skewbacks I8, against which rests the front edge of the arched roof I9. The furnace front wall 20 is shown with a vertical outer Aface and with a sloping inner face, against which is carried a layer 2I of the bottom material. The water cooled door frame 22 extends from the floor plate level at` 23 to the top of the channel irons I'I. As best shown in Figure 1, this water cooled door frame has an opening 24 therein which has a rounded upper portion 25 conforming to the shape of the arch 26 across the top of the door.

The side walls of the doorway are inclined inwardly so that the bottom 21 of the doorway is materially narrower than the upper portion. In Figure 1 a charging box 28 has been indicated in broken lines and it will be noted that the slope of the side walls of the doorway are upon approximately the same angle as the side walls of the charging box indicated. 'I'he doorway is of suicient height so as to take care of scrap which extends above the charging box, such scrap having also been indicated'in broken lines in Figure 1. In accordance with usual practice, the door frame may have two side portions connected by the upper portion, the extremities of the two side portions being secured to a bottom door sill. The door frame of the present invention departs from the usual practice, however, in the particular that the two legs of the U-shaped construction converge, downwardly toward the sill to produce the inclined side walls conforming to the inwardly and downwardly inclined side walls of the doorway opening in the furnace wall. y

As shown in Figure 3, the water cooled door frame 22 is provided with vertically extending guideways 29 between which the vertically movable door is guided in its movement. in Figure 3 the door frame is secured by bolts 30 to the adjacent buckstays I5. The slope of the furnace wall is shown in Figure 3 where it is apparent that the bottom material 2| extends on a slope not only toward the center of the hearth but also toward the doorway. Thus the fact that the sides of the doorway are inclined inwardly and downwardly not only provides a more emcient doorway in working the furnace. but permits the brickwork of the walls adjacent the doorway to be adequatelyprotected by refractory material. It permits the walls intermediate the plurality of doors usually provided in the furnace wall to be properly prf-Iected with material lying on the slope without a break in the protection adjacent the doorways.

While I have shown certain preferred embodiments of my invention, it is to be understood that it is capable of change and modification to meet varying conditions and requirements and I contemplate such changes and modifications as may come within the spirit and scope of the appended claims.

I claim:

l. In a furnace, a wall of the furnace having a doorway formed therein, the outer face .of the wall being substantially vertical. and the inner face of the wall being upon such an angle that bottom-making material will lie on said wall. bottom-making material extending up on said wall, the doorway in the wall having downwardly and inwardly inclined sides whereby the bottom of the doorway is narrower than the top, and the doorway being larger on the inner face of the wall than upon the outer face of the wall, the opening flaring toward the inside of the furnace.

2. In a furnace, a wall of the furnace having a doorway formed therein, the outer face of the wall being substantially vertical and the inner face of the wall being upon such an angle that bottom-making material will lie on said wall,

.bottom-making material extending up on said wall, the doorway in the wall having downwardly and inwardly inclined sides whereby the bottomA of the. doorway is narrower than the top, and the doorway being larger on the inner face of the wall than upon 4the outer face of the wall,l

the opening flaring toward the inside of vthe furnace, and bottom-making material on the 'flared walls of the door opening.

GEORGE L. DANFORTH, JR.

As shown y

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