US2405363A - Checker for open-hearth regenerative furnaces - Google Patents

Description

l.. B. LNDEMuTl-a CHECKER FOR OPEN HEARTHREGENERATIVE FURNACES Filed March 29, 1944 '.5'l Sheets-Sheet 2 f f l INVENTOR.

BY ,vm

WITNESSES.

m; ,1946. 1 B. LINDEMUTH CHECKER FOR OPEN HEARTH REGENERTIVE FURNACES Filed March 29. 1944 3 Sheets-Sheet 3 INV ENTOR.

rf/AIL/ /f Patented Aug. 6, 1,946

UNITED STATE TENT OFFICE CHECKER FOR OPEN-HEARTH REGENERA- TIVE FURNACES Application March 29, 1944, Serial No. 528,524

3 Claims.

The invention relates to checkers for open.

hearth regenerative furnaces, particularly thos used for making steel.

In the operation of an open hearth steel furnace much dirt and dust, including fine oxide particles, is carried by the hot gases to the checkers, on horizontal portions of which a substantial amount of the dust is deposited. Because of the character of the dust and the heat to which it is subjected, deposits of it grow in sponge-like fritted form and clog passages through the checker. This makes it necessary to clean the checkers from time to time, which is diicult to do except their tops. To clean the passages through a checker to the limited extent that this can be done, it is usually necessary temporarilyl to shut down the furnace.

As usually constructed, the life of checkers has been approximately that of the open hearth steel furnace with which they are associated, and the checkers have been rebuilt when the furnace has been closed down for reconstruction. A recent development in the construction of open hearth furnaces is the use of basic brick for their roofs which has extended the lives of the furnaces three or four times that of those having the usual silica brick roofs. An object of this invention is to provide for such furnaces checkers Whose lives will be that of the furnace so that it will be unnecessary to close the furnace down for the purpose of rebuilding its checkers.

The invention provides for an open hearth regenerative furnace a checker constructed of brick that are so shaped and laid as to form a plurality of Vertical flues which extend from the top to the bottom of the checker in such a continuous fashion as to have no horizontal ledges on which dust can deposit, except the top of the checker which can readily be cleaned from time to time without interrupting the operation of the furnace.

The checker is constructed of brick laid in continuous vertical columns which are arranged in parallel planes, the columns lying in each plane having their adjacent ends spaced from each other. 'I'he ends of columns lying in adjacent planes overlap each other so that a continuous vertical flue is formed between the ends'of a pair of adjacent columns lying in one vertical plane and the sides of two columns lying in adjacent vertical planes.

While the flue-forming columns may be formed of plain brick, they are advantageously formed of brick having vertical ribs lat their ends, the prefered form of brick having two vertical ribs at each of its ends so that itis shaped like an I-beam. The horizontal joints of brick forming the columns in each vertical plane are vertically offsetfrom the horizontal joints of brick forming the columns in each adjacent plane so that thermal lateral expansion of the brick will not move the columns out of alignment and present dustreceiving ledges. preferably eiected by using half brick or one and one-half brick at the bottoms'of the columns 1ying in alternate vertical planes thereof and half bricks at the tops thereof or at the tops of the other columns.

To facilitate the laying of the columns, the horizontal meeting faces of the brick are provided with interlocking detents of a suitable form to align brick vertically and also to restrain vertically adjacent brick against movement with relation to each other. However, such detents are preferably omitted from the brick forming the tops of the columns, such brick having smooth tops so that they will not be engaged and moved by the cleaners or dust removers which from time to time are moved over the top of the checker.

The invention is illustrated in the accompanying drawings, of Which Fig. 1 is a horizontal sectional view of a checker, the plane of view being indicated by the line I--I, Fig. 2; Fig. 2 a vertical longitudinal sectional View taken on the'line II-II, Fig. l; Fig. 3 a vertical transverse sectional View taken on the line III-III, Fig. l; and Figs. 4 and 5 perspective views of full size and half size brick used in forming the checker.

The checker is built within end walls l and 2, and sidewalls 3 and li, and has a bottoml 5 and a top E. The length of the checker between its end walls I and 2, and its width between its side walls 3 and t, as well as its height, may vary according to the requirements of service. The top of end Wall l is provided with a gas or an air inlet l connecting with a furnace, which on reversal of the furnace becomes an outlet for products of combustion, and end wall Z is provided with a gas outlet 8 for products of combustion which on reversal of the furnace becomes a gas or an air inlet. Extending longitudinally of the checker and resting upon its bottom 5 there is a wall li) which is provided with cross fiues l l and whose upper portion supports the adjacent ends of arches I2 that are supported at their other ends by walls 3 and 4. Resting on the tops of these arches there are blocks I3 on whose upper faces flue-forming columns rest.

Except for the top and bottom courses of some l columns in the checker, each column is formed of brick l5 of the I-beam shape shown particu- This breaking of the joints is larly in Fig. 4, the brick having a flat main body of rectangular shape and being provided at both sides of each end With vertical ribs I1. The tops and bottoms of the brick are provided with interlocking detents of suitable form which may be a transverse groove I8 on the top and a transverse projection I9 on the bottom of each brick. The top brick of each column having a half brick at its lower end may be the same as the brick i except that the upper face is plain, or it may be a half brick 2!! such as shown in Fig. 5. Brick 20 is the same as the brick I5 except that it is half the height and its top is plain, or in other words, not provided with a groove. While various size brick I 5 may be used, a suitable full size brick may be 131/2 inches long, 6 inches high and 2 inches thick throughout its main body, its end ribs I'I extending one-half inch from the face of the brick and each having a face 11/2 inches in Width. When brick of this size are used they form flues that are e x lOl/2 inches in cross section. By using brick of this form and thickness the entire volume of the brick is electively used for absorbing and giving off heat.

The brick just explained are laid in vertical columns arranged in parallel vertical planes, alternate planes thereof being indicated by the dot and dash lines 25 and 26 on Figs. 1 and 3. The end ribs Il of the brick forming each column in cach vertical plane 25 overlie and contact with the faces of the like ribs at the ends of the brick forming the columns in each adjacent vertical plane Thus a continuous and uninterrupted vertical flue 21 is formed between the adjacent ends of adjacent columns lying in one vertical plane and the sides of two columns lying in adjacent vertical planes. As shown in Figs. 2- and 3,

there is a half brick 2li at the bottom of each column lying in alternate vertical planes thereof, and a half brick 2B at the tops of such columns. The other columns are formed of full size brick l5, except that the top brick in each such column may be plain instead of being provided with a groove.

To eliminate dust-receiving ledges on the tops of the column supporting arches I2, the blocks I3 that rest upon these arches have bases of the same width as the arches and have tops the same width as ribs I'I of the column-forming brick.

Between the tops and bases of these blocks their 1 sides are tapered as shown in Fig. 2, the taper being so steep that dust Will not deposit on their faces. Also, to prevent dust from depositing upon the top of Wall I il between arches I2, triangular-ly shaped blocks 3G are placed upon the top of this Wall, th'e base of such blocks being of the same Width as the thickness of Wall Ill. Thus from the top to the bottom of the checker the dues 2'! are continuous and their walls are free from horizontal dust-receiving ledges. Preferably there are no cross ilues connecting these vertical ilues.

Because of the interlocking `detents IS and IS formed on the horizontal faces of the brick, the columns may readily be laid with unskilled help, and in the upper courses of the columns these interlocking detents restrain the brick against moving longitudinally with relation to each other when a cleaning tool is moved over the top of the checker for removing dust deposited on it. As is well known, cleaning tools for this purpose are usually formed of pipes, each having a laterally extending perforated head for discharging on the top of the checker compressed air led through the pipe. The cleaning h'ead of the tool rests upon and is moved over the top of the checker. If the upper faces of the brick forming the tops of the columns were provided with detents, the movement of the cleaning ytool would be liable to engage the detents and move the upper courses of brick. This would throw the iiues out of alignment and present dust-forming ledges at places which are not readily accessible to cleaning.

The columns lying in each vertical plane thereof being spaced at their ends from veach other, thermal expansion of the brick horizontally in the plane of the columns does not throw the columns out of alignment because each brick is free to expand lengthwise. Expansion of the brick transversely of the checker is transmitted from one column to another through the vertical ribs at the end of the brick, but the staggering of the joints of the columns lying in alternate vertical planes precludes such thermal expansion from throwing the columns out of alignment.

According to the provisions of the patent statutes, I have explained the principle and operation of my invention, and have illustrated and described what I now consider to represent its best embodiment. However, I desire to have it understood that, Within the scope of the appended claims, the invention may be practiced otherwise than specifically illustrated and described.

I claim:

1. A checker for an open hearth regenerative furnace, comprising flat brick having lateral ribs at their ends laid in continuous vertical columns arranged in parallel vertical planes with said ribs extending vertically, the columns in each said plane having their adjacent ends spaced from each other and having said end ribs overlying and contacting with those of the columns lying in each adjacent plane to form a plurality of vertical smooth-Wall ues extending continuously from the top to the bottom oi the checker, arches below said columns extending at Vright angles to said vertical planes thereof, and blocks vresting upon the tops of said arches and supporting the ribbed ends of said columns, said blocks having bases of the same Width as the tops of said arches and having tops of the same widths assaid ribs and having tapered sides between their bases and column-supporting top.

2. A checker for an open hearth regenerative furnace, comprising bricks laid in continuous vertical columns arranged in parallel vertical planes, the columns in each said plane having their adjacent ends spaced from each other and having at their ends vertical sides that are parallel to said vertical planes, said vertical sides of each column overlapping the like sides at the ends of columns in each adjacent plane to formv a, plurality of vertical flues extending continuously from the top to the bottom of the checker, each column forming said iiues being free thermally to expand and contract laterally in the direction of said vertical plane in which it lies, the horizontal joints of the bricks forming the columns in each said vertical plane being vertically offset from the horizontal joints of the bricks forming the columns in each adjacent plane, the tops of the columns being smooth and lying in a horizontal plane, and the horizontal meeting faces of the bricks that constitute each column being provided with interlocking detents aligning the bricks vertically and restraining vertically adjacent bricks against lateral movements with relation to each other.

3. A checker for an open hearth regenerative furnace, comprising flat bricks having lateral 5 ribs at their ends laid in continuous vertical columns arranged in parallel vertical planes with said ribs extending in vertical alignment at the ends of each column and h'aving their side faces lying in planes parallel to said vertical planes, the columns lying in each said vertical plane having their adjacent ends spaced from each other and having said side faces of said ribs overlapping the like faces of the ribs at the ends of columns in each adjacent plane to form a, plurality of vertical ues extending continuously from the top to,

the bottom of the ch'ecker, each column forming said iiues being free thermally to expand and con-

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