USRE13782E - And one - Google Patents

Description

N. E. MAGGALLUM. PROCESS AND APPARATUS FOR THE MANUFACTURE OF STEEL.

' APPLIOATION FILED MAY 26, 1914.

Reissued July 28, 1914. I

2 SHEETS-SHEET 1.

INVEIYTOR jyomm Efl/zw'ca/kznz. I WITNESSES W ,7? I

ATTORNEY f BY I N. B. MAGCALLUM. PROCESS AND APPARATUS FOR THE MANUFACTURE OF STEEL.

APPLICATION TILED IA! 16, 1914,

Reisslied July 28, 1914.

l I L ATTORNEY genera tors over the hearth and the gaseous products of generators which. had been reheated during outrun STATES PA JENT oFFicE.

NURll/IAN E. MACCALLUM, OF PHOENIXVILLE, PENNSYLVANIA, ASSIGNOE OF ONE- FQURTH TO FRANK P. NORRIS OF PHOENIXVILLE, PENNSYLVANIA, AND ONE- FOUR'IH TO THE PHOENIX IRON COMiPANY, OF PHILADELPHIA, PENNSYLVANIA,

A CORPGRATIUN 9F PENNSY JVR NIA.

PROCESS AND APPARATUS FOR THE MANUFACTURE OF STEEL.

flriginal No. 1,057,564, dated April 1, 1913, Serial No. Serial No.

To all whom it may concern lie it known that 1, Norman E. lilaooanmm, a citizen of the United States, and a resident of Phi'ienizcville, county of Chester, and State of Pennsylvania, have invented a certain new and useful Process and Apparatus for the ltflamifacture of Steel, of which the following is a specification.

llcretol'ore, it has been customary, in the manufacture of open hearth steel, to utilize a furnace contiprising an oblong hearth arched over by a roof; two pairs or sets of checker chambers or regenerators, one pair being arranged adjacent each end of the heari; means for supplying gaseous fuel and air to thehearth alternately through the two sets of regenerators; and a stack suitably connected to be placed in communication with the hearth alternately through the two sets of regenerctors, to receive the gaseous products of combustion or exhaust or waste gases from the hearth. In the operation of this furnace as heretofore constructed, it is customary to first heat the furnace by means of a wood fire until the regcnerators, or one set of the regcnerators, have attained a dull red heat. The gaseous fuel is then passed inwardly through one, and air is passed inwardly through the other of one set of the regenerators, that havebeen thus heated, the gaseous fuel and the air being preheated by these hot regenerators and passing from this set of rethrough corresponding ports provided therefor in the furnace. The gaseous-fuel and air then unite in combustion combustion or exhaust gases are then led outthrough a second pair of ports provided therefor opposite the first mentioned pair of ports, and then through the other pair of regenerators, the waste gases reheating the checkers, in the latter regcnerators vand finally p2 ssing out through the stack.

At frequent intervals, the currents of gaseous fuel and air are reversed and caused to flow inwardly through the pair of reihe precedingperiod by the exhaust gases,- and the exhaust gases are discharged through been serving during the preheating period,

Specification of Reissued Letters Patent. Reissued July 28, 1914,1

671,480. Application for reissue filed May 26, 1314 $41,167.

as inlets for the air and gaseous fuel. These" reversalsare maintained regularly until the furnace has been brought to a full melting heat and has been charged, and .until the charge is ready to tap, the gaseous fuel being conducted into the furnace alternately through the same two regenerators, one of .each pair which are known as the gas rcgenerators, and the a1r being always con-- posits, of flue dust, comprising probably iron oXid, slag, etc, which settle upon and adhere to the checkers in the two regenerators, the two regenerators which have been a known as the air regenerators being espe cially subject to these deposits, and to such an extent as to become very much clogged, and to necessitate periodical interruptions in the operation of the furnace and the removal of the deposits, or the replacement of the checkers, or the rebuilding of the regenerators. This removal of the deposits has been accomplished only by a slow, laborious, and expensive mechanical process, and could not be undertaken until the operation of the furnace had been entirely stopped and the furnace allowed to cool down for a considerable period. Also replacement of the checkers in the regenerators is expensive and requires a complete interruption in the operation of the furnace for a considerable period.

One of the objects of this invention is to provide an improved process and an im proved apparatus'for the manufacture of open hearth steel, the improved furnace comprising two pairs of checker chambers or regenerators, which, by the application of the improved process, will be kept substantially free from-objectionable deposits,

such as have been incident to the use of're periodical interruption and costly repairs hereinbefore noted, necessitated by such deposits, will be, to a large extent, obviated (lther objects of this invention will appear hereinafter.

This invention may be briefly indicated by stating that l have discovered that, if, in a furnace of the character above described, instead of supplying gaseous fuel to the furnace always alternately through the same two regenerators, known as the gas regenerators, and the air always alternately through the other two regenerators, known as the air regeuerators, the. operation be reversed occasionally, and the fuel be supplied alternately through the air regenerators, and the air be supplied through the gas regenerators, the objectionable deposits hereinbefo-re noted will not accumulate to any appreciable extent in any of the regenerators, and the loss of efficiency and periodical interruptions heretofore caused bv such deposits will be much less frequent. This very desirable result has been obtained in the actual practice of this invention, but no attempt is here made to explain any theory or theories upon which this result might be based, as the chemical or other actions involved may not be fully understood at this time. The improved apparatus and. the improved process, forming the subject matter of this invention, are, however, fully described hereinafter, so that the construction and operation of the apparatus .and the practice of the process may be effected by those skilled in the art.

In the accompanying drawings, Figure 1 v is a fragmentary horizontal section of afurnace constructed in accordance with this invention; Fig. 2 a fragmentary vertical section of the same on line 2--2of Fig. 1, and Fig. 3 an enlarged fragmentary horizontal section of the same on line 3-3 of-l ig. 2.

One embodiment of this invention comprises an open hearth steel furnace including the usual or any suitable hearth 10 arched over by the usual or any suitable roof 11. At each end of the furnace are two ports 12 and 13 opening into the space between the hearth 10 and its roof 11. These two ports are preferably arranged one above the other, and the upper port 12 is primarily intended to be used alternately for the inlet of air and for the outlet of exhaust gases, and the lower port 13 is primarily intended to be used alternately for the inlet of gaseous fuel and for the outlet of exhaust gases. The upper port 12 is generally called and will be referred to hereinafter as an air port, and the lower port 13 is generally called and will be referred to hereinafter. as a gas port. Adjacent each end of the furnace and preferably in a plane below the arch 10 are two regenerators or checker chambers 1st. and 15, of .the usual or any suitable conraves struction, the interior of each regenerator being preferably sub-divided into a plurality of passages by bricks or checkers 16.

One regenerator 14;, of each pair or set communicates with the corresponding air port 12 through an upwardly extending passage or flue 20 leading from the inner end of the regenerator to the port, and will he referred to hereinafter as an air regenerator, being intended primarily for regenera tion or preheating of air.

The other regenerator 15, of each pair communicates with the corresponding gas port 13 through an upwardly extendingpassage or flue 21, leading from the inner end of the latter regenerator to the gas port. This latter regenerator will be referred to hereinafter as the gas regenerator, being in tended primarily for the regeneration or preheating of gaseous fuel.

There is also provided a gasproducer (not shown), or other source of supply of gaseous fuel for the furnace, and a stack 25 is provided for the passage of exhaust from, and to create a suitable draft through, the furnace.

For controlling the flow of gas, air and exhaust gases, through the furnace, two valves 30 and 31 are arranged between the two sets of regenerators. These valves may be of the usual reversing type or foursway construction, controlled by the rotation of a movable plug. One, 30, of these valves which may be referred to hereinafter as the gas reversing valve, is provided with and controls four openings, 35, 36, 37, and 38, connected respectively to the stack 25, the source.

of gas supply, and the'outer end of each of the two gas regencrators 15 by suitable conduits 39, 4-0,- il and 42. The other, 31, of these valves, which may be referred to hereinafter as the air reversing valve, is also provided with four openings 45, d6, i? and 48, connected respectively to the stack 25, the source of air supply, and the outer end of each air regenerator 14- by suit-- able conduits 39, L9, 50 and 51.

The construct-ion and the arrangement of the reversing valve 30 and its connections are such that, by the proper adjustment. of the valve 30, gaseous fuel or gas from the vs I source of gas supply may be directed by the valve inwardly through one gas regenerator 15, and at the same time, the exhaust gases,

- 31, the air may be directed through the air .31. thus used, the branch gas conduits 55 and 56 'may be omitted.

valve 31 and'inwardly through one of the ;air regenerators 1a, and at the same time,

exhaust gases may be directed outwardly through the other air regenerator 1 k and through the air valve 31 and, tothe stack 25; or the a r valve 31 may be adjusted to reverse the flow of air and exhaust gases through the air regenerators 14; or the air valve 31 may be adjusted to connect both air regenerators to the stack.

The conduit L0 between the reversing gas valve 30 and the source of gas supply is controlled by a three-Way valve 54, having three openings connecting with the reversing gas valve, the source of gas, and the source of air supply respectively. This three-Way valve 54 may .be adjusted to cut off the supply of gas from. the reversing gas valve 30' and to substitute a supply of air, or the reverse, or to close the conduit 40.

For supplying gaseous fuel to the furnace through the air regenerators 14-, the conduit 50 leading into the outer end of one of the air regenerators is provided with a branch gas conduit 55, the outer end of which com- 'municates with the source'of gas supply,

and the conduit 51, leading into the outer end of the other airregenerator, is provided with a branch gas conduit 56, also communicating with the source of gas supply. These branch conduits 55 and 56 are controlled by valves 57 and 58 respectively. The air conduit 49, leading from the surrounding atmosphere to the reversing air valve 31, is alsocontrolled by a valve 59, so that the supply of air may be out offfrom the air reversing valve 31, when it is desired to utilize either of these regenerators for the passage of gas from either of the branch conduits 55 and 56. This valve 59 may be in the form of a three-way valve and be connected to the source of air supply or gaseous fuel by a branch conduit 60 so that the valve may be used to cut ed the supply of air from the air reversing valve 31 and substitute a supply of gaseous fuel, or the reverse, or to close the conduit 19 and cut off both the supply of air and the supply of gases from the air reversing valve When a three-way reversing valve is In the operation of this improved furnace, the furnace is first heated in the usual manner by a wood or coal fire untll the regenerators or checker chambers lt and 15 have at-' tained a dull red heat. During this period the air and gas reversing valves 30 and 31 and the other controlling valves of the furnace are preferably adjusted, so as to connect both sets of regenerators to the stack 25, After the regenerators have been thus heated, the gas and air reversmg valves spending 30 and 31 and the other controlling valves of the furnace are preferably adjusted, so as to direct the air and the gaseous fuel or gas inwardly throughthe air regenerator 1 1 and the gas regenerator 15, respectively, of one set of the regenerators, and simultaneously to direct the gaseous prodacts of combustion of the furnace outwardly through the two regenerators of the other set. The air and gas passing inwardly are preheated by the hot regenerators and pass from the regenerators through the corre ports 12 and 13 and into the space above the hearth 10, where the gas and air unite in combustion, the gases of combustion then passing out through the other pair of ports 12 and 13 and then through the other pair of regenerators 1e and 15, and finally out through the stack 25. At frequent intervals, the currents of air and 5 gas are preferably reversed a d are caused to flow inwardly through thr, pair of regenerators which have been reheated during the preceding period by the exhaust gases, and the exhaust gases are discharged through the other pair of regenerators. These reversals are preferably made with'gradually increasing frequency'until the temperature of the furnace has been raised to a full melting heat. The furnace is then charged with the usual steel making materials, and the reversals of gas and air and gaseous products of combustion are continued as just described, the reversals noW being generally made every fifteen or twenty minutes. Ordinarily, in thus reversing the currents of gas and air, the gas is changed from one gas regenerator '15 to the other gas regenerator 15 and theair is changed accordingly, but, to avoid the accumulation of objectionable deposits, as hereinbefore described, occasionally, in reversing the currents of air and gas, the-gas is changed from the regenerator 15 to the airtregenerator lt of the other set, andthe air is changed from the air regenerator 14 of one set to the gas regcnerator 15 of the other set. The air and gas or gaseous fuel are then run,- for several reversals, through the gas and air regenerators respectively.

It has been found that by running the gas through th air regenerator of one set of regenerators, and the air through a gas regenerator of the same set, for two or three reversals, every other heat, and doing the same with the other set of regenerators on the alternate beats, and during the remainder of the time alternating the gas through the gas regencrators and the air through the air regcnerators tors will be kept substantially clear of the objectionable deposits noted. It has also been found that these reversals of the air and through. the and air regenerators respectively, are particuiarly effective the regenerafor the purpose descrihed,; if accomplished just after the bath has become n olten and the lime is rising to the surface: of; the hearth. r I X Although onlya single for rn of -apparatus has been illustrated in which this iii'ventioh may be embodied, theinvention is not li' ed to the specific construction disclosed, as is evident that Various modifications might be made in the construction, and that the inventionmig'ht' be applied te various other forms of apparatus". Furthermore, as gas and air regeneretors' are used for-various purposes, it is evident that the invention is not limited in its scope to an apparatus or to a process for the manufacture of steel, but might be applied to other apparatus i or other purposes, Without departing from the spiritof the invention or the scope of the ,ap ended claims.

iaving thus fully described this invention, I claim and desire to protect by Letters Patent of the United States: i

, '1. The combination with two regeneretors, of means for supplying either oii-said regen'erators selectively with gaseous fuei and theother regenerate): with air.

2. The combination with two regenera tors, of means for supplying elther of semi regenerators selectively with gaseous fuel, and the other regenerat r with a1r,end means for reversing the process by supply:

ing the first mentioned regenerator with air and the second mentioned regeneretor with gaseous fuel.

3. I'm-a rurnece, thecombina'tion ritli'e hearth, or a pair-of regenerators COHil1 ldflk eating with said heartluend means for supplying either of said regeneretors selectively with air and the other regeneretor with.

gaseous fueL 4. In a furnace, the combination 'iiitkja hearth, of'tWo pairs of regeneratorsco nn iunicating, therewith, means for supplying either regenerator of either pairselectiveiy with air and the other Withgaseous fuel, and

means for-directing exhaust gases from the hearth silriiultaneously outwardly through" tion consecutively and in the order named through is regenerator chamber.

6. in the manufacture of steel, the process Whichconsists of passing gases oi combustion from .a furnace outwardly through a regenerator, then passing air inwardly through the regenerator, then passing gases of combustion outwardly from the furnace through the regeneretor, and then passing gaseous fuel inwardly through the. regenerat'or.

f7. The process of keeping clean the interior regenerative surfaces iii a heated regenerator chamberof an open hearth steel furnece, which coinprisesth steps ofpassing air and combustible gas in relative alternationl threugh such regenerator chamber, each such alternation being maintained a sufficient time to remove any deposits from such surfaces. v I

p lhe recess of removing incombustible deposits rein en air regenerator, Which corn iris es the ete or" assin coinbustible v 'ireirgh theeir regenerators. 3:. mess whereof have hereunto set my hsnothis 20th dayoi May 1914:. p

" ire-s ren n. Meet m htier.

W. V M p p B. A. uoosrrnerr.

.Q'e'r removing or preventing" rough trie gas 'regenerators and fresh

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