US1831354A - Furnace - Google Patents

Description

,Nofv. 10, 1931. w. lsAAcs ET AL 1,831,354

FURNAGE` Filed April 19, 1929 2 sheets-sheet 2 Patented Nov. 10, 1931 UNITED STATES PATENT oFFlcE -WILL1AM ISAACS, OF STRTHER'S, .AND ELMR E. MCVEY, 0F YOUNGSTOWN, OHIO FURNACE Application mea April 1a,

Our invention relates more particularly to open hearth regenerative furnaces such as are commonly employed in the steel industry although it is equally applicable to other 5 forms ofregenerative furnaces intended for other purposes. l

Open hearth regenerative furnaces as usually constructed comprise the furnace proper including the hearth, a set of regenerators disposed near each end of the furnace at a -lower level than its hearth and passages respectively extending therefrom through which the incoming heated air and gas is conducted to the furnace from one set of regenerators and the waste gases discharged from the furnace into the other set of regenerators. 'In accordance with the usual' spective of the particular arrangement of the regenerator chambers with the result that the heated gas which is under considerable pressure, tends to leak through any cracks or openings in the wall and miX with the air in the air passage. As both ythe air and gas are in highly heated condition, ignition immediately takes place in the air passage and' the wall adjacent the cracks where the gas has leaked through is burned away graduall in cone-shaped depressions, while, additionally, this premature ignition and burning of the air and gas in the air passage renders proper control of the furnace impossible with consequent enhancement of operating costs and generally unsatisfactory operative re' sults.

While initially the leakage of the gas through the division wall between the gas and air passages may be relatively slight it proceeds-in progressively greater amounts as time goes on for the burning away of the wall adjacent the leaks and consequent formation of the cone-shaped depressions or holes there- 5 in facilitates the passage of the gas so that 1929. Serial No. 856,518.

more and more'of it leaks through and is burned in the air passage while the wall, in turn, burns further and further away until it becomes so honey combedeither locally or throughout its entlre extent from the regenerators to the throat of the furnace that it is useless for its intended function, and the furnace must then be shut down and kept out of commission until the division wall can be repaired or replaced..

A principal object of our invention, therefore, is the provision of means for preventing the leakage of gas from the gas passage to the air passage in an open hearth or likefurnace whereby premature ignition of the air and gas in the air passage with consequent erosion of the division wall between the passages and shortening of its effective life as well as loss of operative control of the furnace is avoided.

Further objects of the invention are the provision of means for the purpose aforesaid which may be readily employed in open hearth or like furnaces without material alteration of the usual structural arrangements thereof, which do4 not materially increase the initial cost of installation and which are entirely satisfactory for the performance of their intended functions.

Other objects, advantages, and novel features of design, construction and larrangement comprehended by our' invention are hereinafter more particularly-pointed out or will be apparent from the following descripy tion of 'an open hearth furnace constructed in accordance with the invention andillustrated in the accompanying drawings.

, As our invention relates more particularly to those portions of the furnace, considered as whole, which concern the conduction of the air and gas from the respective regenera tive chambers to the throats of the furnace adjacent 'the ends of its hearth, and as regenerative furnaces are usually similar at both ends. we have.v in the accompanying 5 drawings. shown only those parts adjacent one end of the furnace which are necessary or desirable for a proper comprehension of our invention.

In thesaid drawings, Fig. 1 is a central, lo.

vetical, longitudinal section. through the end of the furnace substantially on the line 1-1 in Fig. 2, and Fig. 2 is 4a horizontal section through the regenerative chambers, gas and a1r passages and adjacent parts substantially on the plane of line 2 2 in Fig. 1. Like symbols of reference are used to designate the same parts in both figures.

The furnace, as shown, save in particulars hereinafter mentioned, is of ordinary construction comprising a vhearth 1 adjacent and above the end of which is disposed the outwardly and upwardly inclined gas port 2 from which the gas is discharged towards the hearth and which communicates at its outer end with a downwardly extending neck 3 in turn communicating by a laterally directed horizontal passage 4 with the gas regenerative .or checker chamber 5 which, in this instance, is disposed laterally of the furnace .hearth and bounded by walls generally designated as 6. Above the gas port 3 is disposed the usual air port 7 through which the air vis discharged toward the hearth and which near its outer end communicates with downwardly extending necks 8 on either side of the furnace inturn communicating at their lower ends with the air passage 9 which extends yfor a short distance parallel to the gas passage and may then be turned slightly angularly forward towards the center of the hearth to enter the air regenerative'or checker chamber 10 bounded by walls generally designated as 11 and located alongside of4 but nearer the center of the furnace than the gas Checker chamber 5, the adjacent walls of these chambers being, in the present instance, spaced apart for a short distance although frequently in open hearth furnace construction these chambers are merely separated by a single division wall instead of two separate spaced walls. The inner ends of the gas and air passages beneath the furnace proper are deepened so as to provide the usual slag pocketsP, P 'to receive 'and hold dust, particles of metal or the like entrained with the y outgoing gases and from these slag pockets Aeo the bottoms of the passages are respectively sloped upwardly as at 13 and 14 so as to enter the regenerative chambers a considerable distance above the floors thereof in the ordinary wayand within `the chambers is disposed the usual checker work, designated as 15. The hearth of the furnace is supported on pillars and beams and the walls by buckstays in the customary manner and as these parts are well understood and may be of any desired or preferred construction and arrangement n'o extended reference thereto is required.

In accordance with our invention instead of providing a single solid division wall be'- tween the gas and air passages 4 and 6, we provide at this point two longitudinally spaced, generally transversely extending walls 16 and 17 torespectively form the adjacent side Walls of these passages and dispose between these walls for the purpose of supporting them a plurality of transversely spaced, vertically extending supports 18 which may desirably consist of steel I-beams of suitable width or depth and of sufficient length to extend the height of the walls 16 and 17 or even, as shown in Fig. 1, to a point a little above their upper ends. The webs of these supports are cut out at spaced points as best shown in Fig. l so as to provide in each support a series of vertically spaced openings 20 and thereby permit a free circulation of air from one end to the other of the passage or space 21 between the walls 16 and 17, whereby any gas which may leak through the wall 16 will be carried away through this passage and thus positively prevented from finding its way into the adjacent air passage 6.

In the particular furnace We have. chosen to illustrate the regenerative air and gas chambers are spaced apart and,.consequently,

the space 22 between the adjacent chamber walls forms in effect a prolongation ofthe passage 21, and this arrangement is usually preferable as it permits a very free and unrestricted air circulation in the passage 21 which, as shown, extends entirely across the furnace and opens to the atmosphere as at 21 on the side of the furnace opposite the checker chambers.

We have shown the checker chambers as arranged laterally of the furnace and the pas-V sage 21 thus extending in a direction generally transverse of the furnace but in some furnaces the checker chambers are located more or less 4in longitudinal alignment with the hearth and beyond the ends of the fur-l nace. In such cases, of course, the passage21 between the Walls 16 and 17 defining the air and gas passages will also extend ina geny erally longitudinal instead of in a transverse their extent with boiler plate or other suitable metal sheathing. This sheathing is shown at 23 on the outer adjacent faces of the walls 16 and 17 and also at 24 on the walls 16 and 17 on the oppositesides of the respective passages. The provision of this sheathing also to some extent enhances the rigidity of the walls and by assisting in the prevention of air or gas leakage through any of them tends to a reduction of the operating cost ofthe furnace.

As in s ite of the utmost precautions which can be ta en, the erosive effects of the highly heated incoming air and gas and also of the outgoing spent gases upon the walls of` the air and gas passages ultimately render these `walls unfit for further service so that their replacement is required, we therefore prefer when constructing the furnace to provide at the upper outer corner of each of the side walls of the passages at its point of juncture with the roof arch, an angle 25 ofsteel or other suitable metal throughout the length of the wall to assist in supporting the arched roofs of the passages when the side walls are torn down preparatory to their replacement.v Thus in accordance with our invention the entrance of gas from the gas passageto the air passage while thegas is passing from its checker chamber to the furnacets entirely prevented with consequent avoida ce of prelgnition in the air passage and resulting loss of operative control of the furnace. Additionally, the constant circulation of air through the passage 21 tends to keep ,the adjacent walls cool and thereby enhances their useful life while any gas which may. in some way leak through the gas passage wall into .the passage 21 is carried ofi' and dissipated accordance with our invention, we do not thereby desire or intend to .limit or confine the use thereof solely to afurnace of that type l as the principles'and advantages of our invention may be readily embodied in furnaces of other types if desired without departing from the'spirit and scope of the invention as defined in the appended claims.

Having thus described our invention we claim and desire to protect by Letters Patent of the United States:

1. In a regenerative furnace having sepa-l rate air and gas regenerators adjacent each of its ends, walls extending from each of said regenerators and defining separate air and gas passages and slag pockets between the regenerators and the furnace throat respectively adapted to conduct air and gas thereto, the walls most nearly adjacent each other being spaced apart to provide between said vpassages and pockets a passage open at both ends and extending throughout their length.

2. In a regenerative furnace having separate air and gas regenerators adjacent each of its ends, walls extending from said regenerators and defining passa es ada ted to separately conduct air an gas om the ,re nerators -to a point beneath the end o the furnace, the adjacent passage walls being separated to provide a space between said walls throughout their length and means disposed in said space operative to support said walls and havin openings where y air can'circulate throug said space.

3. In a regenerative furnace having separate air and gas regenerators adjacent each of its ends, walls extending from said regenerators and defining passages adapted to separately conduct air and gas from the reenerators to a point beneath the' end of the rnace, the vadjacent passage-dening walls being separated throu hout their length to' provide an'open ende space between'said :walls and means operative to support said walls comprising a plurality of spaced I- beams having perforated webs disposed in said space whereby air can freely circulate between the walls throughout the length o'f said space.V

4. In a regenerative furnace having separate air and gas regenerative chambers adjacent each of its ends, walls extending from said chambers to a point beneath the end of the furnace and definin slagI pockets and air and gas passages res ectlvely extendin thereto from said cham ers, those of sai walls which are most nearly adjacent being spaced v apart throughout their length to provide a passage disposed between said slag pockets and open at its ends adapted to permit a' circulation of air between, said walls from one end of the passage to the other.

Intwitness whereof we 'have hereunto set our handsthis 16th day of April, A. D. 1929.- Y WILLIAM ISAACS..

' ELMER E. MCVEY.

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