USRE14032E - Paib-heatmg-furwace hearth - Google Patents

Description

T V. ALLIS.

FARR HEATING F RNACE HEARTH.

APPLICATION FiLED OCT. 30, 1915 lie-issued Dec. H, 1915.

T. V. ALLIS.

PAIR HEATING FURNACE HEARTH APPLICATION FILED 0C1. 30. l9l5.

. Rgisued Dec; 14, 1915.

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T. v. ALLlS.

PAIR HEATING FURNACE HEARTH.

1 v APPLICATiON'HLED OCT. 30, 1915. Rewsued D00. 11-, 1 91:).

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WH'NESSES UNITED STATES PATENT ornron.

THOMAS ,71." ALLIS, 0F PITTSBURGH, PENNSYLVANIA.

PAIR-HEATING-FURNACE nnsnrn.

Specification of Reissued Letters Patent. Reissued Dec, 14 1915 Original No. 1,034,858, dated August 6, 1912, Serial No. 453,977. Application for reissue filed October 30,

1915. Serial No. 58,915.

To all whom it may concern:

Be it known that I, THOMAS V. ALL'Is, acitizen of the United States, formerly residing at Bridgeport, in thecounty of Fairfield and State of Connecticut, but now residing at Pittsburgh, in the county of Allegheny and State of Pennsylvania, have invented certain new and useful Improvements in Pair-Heating-Furnace Hearths; and I do hereby declare this following to be a. full, clear, and exact description of the invention such as will enable others skilled in the art to which itappertains to make and use the same.

My invention relates to pair heating turnacesand it consists of an improved hearth designed to be used in the heating chamber sible, thereby giving the ,out, so

been progressively wlthdrawn along the hearth, those at the opposite end from. '45

of such furnaces to uphold sheet bars placed thereon, supporting them upon one of their sides, and a lower edge in a position inclined laterally to the perpendicular, thereby economizing space and increasing the heating capacity-of such chamber, and whenemployed in continuously heating such bars, it enables them to be forced along the hearth in parallel rows. The benefits derived from the use of my improved hearth in the ordinary pair heating chamber of the present sheet mill furnace consist: First, in the ability to charge a greater number of saidl bars thereinall more advantageously locatld than now pos- 1 the necessary time to become mellowed liy the mild soaking heat required for th: purpose. Second, by heating the bars slowly they are brought to the proper rol ing temperaturewithout raising damaging,scale upon their surface. Third. more continuous working is possible for the reason that cold bars may lsooh be charged afterthe hot bars are taken that, by the time the hot bars have which the hot bars were last drawn are in condition to roll, thus a system of rotative heating is established. Fourth, more bars .are heated per unit of fuel consumed, from the factthat the hearth constantly receives and discharges the bars uniformly. Eifth,

the work of the heater is less laborious as he not, under all conditions, obliged to tinuous heating furnace taken on line a, a,

of Fig. 2 and shows in plan. collections of sheet bars out to length with their ends crossed in reverse angular abutment and up held upon my improved hearth within the heating chamber of said turnace. Fig. 2 is a transverse section on line 7), b, of Fig. 1..

Fig. 3 is a section broken from said hearth through its base and the center of a portion of its vertical projections. with sheet bars standing in the grooves thereon formed by a said projections and in reverse angular abutment; two of the collections of bars are shown in cross section. and portions of two in end elevation, all enlarged. Fig. 4 is an enlarged plan view of my improved cast steel hearth shownin Figs. 1. and 2: the base has integrally connected individual projections disposed over its top surface, which form a series of parallel groovcssuitable to uphold therein sheet bars inaugular position. Fig. 5 is a transverse vertical section on line 0. c, of Fig. l. Fig.5 is a plan view in longitudinal section on line (i, (Z of Fig.7 and shows the improved hearth constructed of burned fire clay or other refractory material and located in the heating chamber of an ordinary pair heating furnace, the fire-box and bridge wall common to such furnaces being shown. Fig. 7 is a vertical longitudinal section on line 0, e of Fig. 6. Fig. 8 is a" plan view in longitudinal section on line f, f of Fig. 9 andshows collections of. sheet bars" all upheld at one inclination upon said health with their adjacent ends separated. Fig. 9 is a vertical longitudinal section on line 9, g of Fig. 8.

Figs. 10, 11 and 12 are sections of varied forms of the hearth which may be constructedlof metal or refractory material.

having their ends twice crossed but sup ihrted more obliquely. Fig. 11, also lilie Fig. .3,

shows sheet bars upheldupon the hearth in r placed against them and at a reverse angle to the preceding charge, the bars rest upon hot supports, so that, by alternating the position ofeach charge, the bars all have hot supports to rest against.

While the hearth of Fig. 12 does not possees the foregoing described characteristics all of the hearths of Figs. 3, 9 and 11 for recuperating heat in the portion 16 of the equiangular projections 13 of those figures;

"the grooves 12 of Fig. 12 are closer together than grooves 12 of Figs. 3, 9 and 10 and 11, which gives the hearth of Fig. 12 greater bar upholding capacity per square foot than the hearths of said figures, the same number of bars being placed in respective grooves.

' In operating my improved hearth in the heating chamber of an ordinary pair heat ing furnace, (see Figs. 6, 7 8 and 9) the bars are charged thereon through doors located in side 18 of the chamber, (doors not shown) singlyor in collection, standing either at the 'sameor reversed inclination.

Before the commencement of a week or workingperiod, and in order to gain time, the hearth is charged with its full complement' of bars early enough to bring them all ,to rolling temperature by the time the turn comes on. Following the withdraw-a1 of the hot bars, at one end of the ,hearth, to be rolled, others are charged to occupy reverse angular hotspaces in the same grooves. This operation is continued until all of the bars extending. over the hearth have been withdrawn, at which time the metal at the opposite ends of the chamber from which heated bars were last drawn is not enough to roll; thus a rotative system ofheating is established which continues throughout the Working period.

To recover heat in the hearth of Fig. 12, the bars are manipulated somewhat differently from those of Figs. 8 and 9, and the act is accomplished by leaving the first groove 12, at the left of the figure vacant at the time the hearth is first charged with bars, which is after the hearth and all parts of the furnace have become thoroughly heated: When, such bars are partially heated, those occupying the first groove at the right of the vacant groove 12 are turned over toward the left into said groove, this leaves the first previously occupied groove vacant and exposed to the normal temperature of the furnace which it soon assimilates; the next row of-bars at the right of this re-heated groove is then turned toward the left into it, and as it is the hot l top bar of the pair that comes in contact with-the now re-heated surface ofthe groove,,such groove is robbed of but little heat. This operation is continued until all of the bars across the hearth have been turned into temporarily vacated and re-heated grooves, at which time, the first be. a are sufliciently hot dred metal.

to roll. After the hot bars occupying the first two grooves 12 at the left end of the hearth have been drawn, cold bars are charged into the sccondgroove 12, which leaves the first groove again open and prepared for a duplication of the operation,

which is constantly repeated.

In operating hearth 12, or any hearth of"- is but little sliding movement of bars over the hearths surface, although the cast steel hearth next below referred to is preferred.

The hearth of Figs. 1, 2, 3, 4: and 5 is the type preferably adopted in the heating chamber of my continuous heating furnace. It is by choice cast steel which is sufliciently refractory to withstand the mild soaking heat required to mellow sheet bars and kin- The hearth extends out in the form of a shelf 17 (Fig. 1) beyond the charging end 19 of said chamber, a sufficient distance to uphold sheet bars of the greatest length. Upon this shelf transverse'rows of the bars are placed singly or in collection,

and in the laterally inclined and lineal posi tion they are to retain while passing along the hearth which is ,in the longitudinal direction of their length as indicated by the arrow, and preferably with their ends twice crossed in reverse angular abutment as shownin igs. 2, 3 and 10, although, if the cha her 7 short, the rows of .bars may be firmed oyer the hearth, all standing at the'sai' angle and direction as shown in Figs. 8, 9 and 12. The shelf 17 being filled, the bars thereon-are next forced within the chamber by a hydraulic ram or any approved means. againrefilled with similar rows of bars which are also forced within the chamber.- This operation is continued until the hearth I is filled with bars its entire length. This completed, the bars are allowed. toremain within the chamber until the transverse row at its discharge end 20 has reached the proper rolling temperature. The bars of this'erow are then withdrawn and rolled. After said transverserow ofbars has been exhausted and the shelf 17 reloaded, the propelling mechanism is again applied to the exterior ends of the transverse, rows of bars standing upon the shelf 17, which forces them into the chamber and at the same time advances the entire charge a distance equal to the length of said rows of bars which occupied the shelf. This action brings a trans verse row ofbars to the discharge end of the The thus emptied shelf is the line of bearing of the rlined positions in the grooves.

chamber properly heated and in position to be Withdrawn the same as said first roiv. This operation is eonstanttv but intermittently repeated throughout the week or working period. The plan of heating bars in a continuous beating Furnace in advance of the first turn at the commencement of a Working period is to be observed the same as that iiereinbefore described in operating an ordinary pair heating furnace.

While I have herein described sheet bars the form of metal my improved hearth is designed to uphold during the process of heating it is obvious that it is equally ivell adapted to the upholding of tin plate. bars or other metal of rectangular form in various lengths wvithin the heating chamber of any suitable type of heating furnace.

It is haraeteristie of my improvement that each of the grooves is so proportioned as to width and depth that the distanee from the surfare against which the lower edges of the sheet bars hear, when placed in into those portions, as the edges 15 which support the sheet bars laterally will, have such relation to the length or width of the sheet bar measuring from surh lower edge, that the bars will he in a state of stable equilibrium, i. 0., will not be liable to move from the'desired angular positions. If the bars are arranged with the longer edges in eontactavith thesurfaee 14, the distance from the latter to side supporting edge 15 should be equal and preferably greater than half the Width of the bars. It is found desirable,in practice toinake the grooves of such dimensions that the largest bars (an be safely supported.

claim herein as my invention:

*1. A hearth'for a pair heating furnace. provided with a plurality of grooves suitable for supporting sheet bars in an inclined position, said grooves being so proportioned that the distanee from the edge supporting surface within the groove to the edge of the lateral support will he suflieient to maintain the sheet bars arranged in inclined positions in said groove in a eondition of stable equilibrium.

"2. A hearth for a pair provided with a plurality for supporting sheet bars'inan inrlined'positi-on. said, grooves being so proportioned that the distanre from the surfare within the groove to the edge of the lateral support will be suilieient to maintain the sheet bars in int-lined positions in said groove in :1 Condition of stable equilibrium. the distaure between adjacent grooves being less than the Widths of the grooves.

3. A hearth for a pair heating furnare provided with a plurality of grooves suitable for supporting sheet bars in an ini-lined position. said grooves being so proportioned that the distance froin'the edge supporting surfare Within the groove to the edge of the lateral support. will be greater than half the distance from the supported ,edgeto the opposite edge of the sheet bars.

4. The herein desrribed hearth of a pair heating furnace,

edge supporting of grooves suitable heating furnare. having its upper side rear posed of a series of parallel grooves which hear such trans'l'erse relation to each other that longitudinal rowso'r' sheet bars in sections. supported alternatel v at a reverse an gle within the grooves and against the sides thereof. will cross at their adj arent ends.

in testimony whereof, I have signed my name to this specification in the presr-nee of' two subscribing Witnesses.- THOMAS Y. ALLIFJ'.

\Vitnesses P

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