US1912933A - Heating furnace - Google Patents

Description

June 6, `1933. A. L. cuLBERTsoN n 1.9125935` HEATING FURNACE f" Filed Jan. 8, 1929 9 Sheets-Sheet 2 #@3567- l.. CUL BEETsO/v,

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June 6, 1933. vA. L. ,CULB'ERTSON 1,912,933

HEATING FURNACE Filed Jan. 8, 1929 `9 Sheets-Sheet 9 \v rc Patented June .1933,

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M` invention relates to forheati ing illets,.bloomsslabs, packsand Asimilar materials, and more particularlytocontinutnisheatin'gv furnaces of therecuperative type wherein the billets,`blooms, slabs, packs and similarg materials `"are `charged into the furnace at or near ,oneend and are discharged o `later near its opposite end,` and are gradually heatedbwhile traveling;throughthe fur- ,y j y The primary object of the invention is the "provision in a furnacel of improved means nace.

whereby thehighilame tem v ratures obtainable by! the use yof preheate air` are utilized ,y while o'vcr-heatingofthe materials is avoided i i and` over-come, the temperatures at` itferent pointsf'in the length ofthe furnace areregulated and controlled, and the,finaterials are "uniformly heated to thedesired uablerollflvde af heating fun having improved ing temperature when discharge from"`the furnacem. i. U Another objectof the `invention is topromeans whereby o scalingand oxidation losses :are lessened, the costof maintenance, operal tion and fuel consumption is reduced, and

the heatingcpapacity and flexibility ofthe `furnace are greatly increased.

l `Still further objects of theinventionwill be made apparent inthe detailed description` fl and be particularly pointed. out in the apo pended claims. o @L f Referring now to the `(lfavvings forming l part Qfthis specification, Figurer it` a sec-m/ tional side elevation showiprlg` a recuperative 's heating furnace uembodyin my invention.l

Figure 2 is a sectlonalsl e elevation, showy ing a modificationin a portion the fur-` nace hearth."` i y ,s

Figure 3 is a sectional end yelevation,taken lfon the irregular line III-IIIfof Figure 1.

Figure 4 is a sectional end elevation on the irregular line IVf-IV of Figurefl. "l

`Figure 5l is `a sectional end elevationon` the line V-V of `Figure 1.

Figure 6 is a sectional Ifthe irregularline VI?- VI of Figure 1.

Fi uref?` isa sectional sideelevation on N fh'e'lmevIIg-vnof Figure 1.

`-Figure 8 `is a sectionalplan, the section side` elevation" on f Fi re ,9, isjafsectional plan on'theiline fIX-lXof Figure 1. i,

y In the `accoinpan ing drawings the `numeral 2, infa generra way, denotes the heating chamber and 3 the soaking chamber of my improved furnace. A vertically restricted channel or throat 4 `connects the ad 'oining ends of thechambers 2 and 3. `The eating chamber "2 is` rovided withwateri ids 5 on `whichwthe cooled ipes forming y billets, blooms, slabs or pieces of other material to be heated are supported within the chamber 2.?

'ne skids 5, ,than mnd fram the` chargin end .of the chamber 2 to anintermediate `point inthe length of the refractory hearth ,PATENT eprice 6 ofthe soaking chamber 3, aresupported for part of their length upon piers 7 and, at

the delivery end of the, chamber 2, by trans- `and then 1 inclines sharply upwardly.` and j oins'the horizontal portion of the roof at the delivery` end of the chamber 2." The roof 10 of the throatv or channelfis fiat and horizontal, as' will beseen in" Figures 1" ande.y The` roof of the soaking chamber hasa slopin ortion 11 which connects at its low `end `w1t fthe roof 10` and at its other end with its flathorizontal portion 12. The furnace, when in operation, will be filled from end to end with successively charged billets or` the like, as shown in Figure 1,. the materials entering the furnace through the charging opening 13 Aand ,being discharged through the gravity "dischar e `outlet 14 at opposite ends ofthe furnace. "of course, will `be understood that after the iece of heated material` fwill be discharged rom the furnace and dei furnace is filled, a

livered to the feed roller table 2Q below the gravity discharge outlet 14 whenever a cold piece of material is charged into the opposite end of the furnace. A charging machine (not shown) will be provided at the charging endy of the furnace to push the pieces of the material being heated into the furnace and, at' the same time, push a heated piece out of the furnace. A modified form of charging-apparatus will be usedwhen the `chargln opening is in the sidelinstead of the end of t e furnace.

When the furnace is filled with billets or other material the row of billets supported on the skids 5 separatesl the heating chamber 2 into an upper section 15 and lower section 16, each of which, and also the soaking chamber 3, is separately andl independently fired, as will be explained later.

In the construction shown in Figure 1, the end 17 of the refractory hearth 18 of the throat 4 extends into the chamber 2 beyond the end of the transverse wall'19 deinin the delivery end of the chamber 2. When ound preferable or necessary, the hearth of the throat 4 will be built as shown in the modification shown in Figure 2.

In this modification, as will be seen b comparin Figures 1 and 2, the refractor earth 18 of igure 1 is omitted fromy the t roat or channel 4 and the lower section 16 ofthe heating chamber 2 is lengthened to bring its end wall 17 in line vertically with the receiving end of thesoaking chamber 3, and the skids 5 are extended across the length of the throat f1.

A door` 21 is provided for the chargin opening 13- andy a swinging door 22 for the gravity discharge outlet 14'and, at advantageous points in its length,`the furnace side walls 23, 24 are rovided with openings 25 which are normal y closed by lifting doors 26.

In order to secure and utilize to the fullestextent the advantages resulting from the use of the high llame temperatures obtainable by usin preheated air in burning the fuel and at t e Sametime, avoid and prevent excessive oxidation of the materials heated in the furnace and the resultant high scaling or melting losses, my improved furnace is provided with three separate and independently operated series orv sets of fuel burners so as to provide a triply fired furnace by which great flexibility in regulation of the furnace temperatures is obtained.

The particular burners shown are adapted for use with natural gas but it will be understood that producer orby-product as, oil, tar or powdered fuel may be used w en desirable or necessary.

In the embodiment of my invention shown there is a series of fuel burners 27 for the upper section 15 and similar series of fuel burners 28 for the lower section 16 of the heating chamber which are arranged for use with preheated air and a series of fuel burners 29, adapted for use with air at atmospheric temperature, is provided in the end wall at the discharge end of the furnace for firing the soaking chamber 3. Preferably the air used with the burners 29 will be at slightly more than atmospheric pressure although burners of the inspirator type may be'used when desired.

Whenlow B. t. u. fuels are supplied to the burners 29, preheated air will be used in order to increase theflame temperature slightly above the temperature of the work being discharged.

It will be seen that by this novel arrangement of burners the vupper and lower sections 15 and 16 of the heating chamber will be fired by the use of preheated air while air at atmospheric temperature is ap lied to support combustion within the soa ing chamber 3. In this way the high flame temperatures obtainable by the use of preheated air are rovided at the end of the chamber 2 adjoining the throat or channel 4, where the intensely heated gasesror products of combustion heat the billets or other materials being heated while'they are yet ata temperature below the required rolling temperature and below that at which loxidation melting and excessive scaling of the heated materials commence. At the same time, the materials soaking within'the soaking chamber 3 are being equalized in temperature by the less intense iiame temperature at this point.

It, of course, will be readily understood that the burned gases or products of combustion withinthe heating chamber 2 are at a temperature much higher than that to which 'metal is heated for rolling. The metal absorbs heat rapidl in this chamber but is unevenl heated. pon entering the soaking cham r 3 it becomes uniforml heated to the rolling temperature during t e time it remains in the soaking chamber.

As the chamber 3 is maintained at a temperature high enou l1 to complete the metal heating operation ut much below the extremely high fiame temperature of the gases at the burner end of the heating chamber 2,

-the metal becomes uniformly heated throughout while passing through the'soaking chamber and, at the same time, is not subjected to the ame temperatures which cause excessive oxidation and scaling.

By reference to Figures 1 and 3 it will be seen that the preheated air for the fuel burners 27 is supplied to the upper section 15 of the heating chamber 2 through ports 30 fromv the transverse air flue 31 that extends horlzontally above the throat 4, from side to side of the furnace, and that the preheated air for the burners 28 is supplied to the lower sectioh 16 of the chamber 2 through ports 32 by the series of vertical ilues or uptakes 33 which connect at their lower ends to the transverse air flue that extends transversely below the throat 4 across the width of the furnace.

Theseries ofburners 29 which arepositioned in ports 34 in theend wall of the furnace are connected inan suitable mannerto "a fuel supply main an to "a source offair under slight pressure to supply a combustible chamber a.

upper section and lower section 16 of the l material "of whic Athe air and a i formed rests on a series of perl orated base lheating chamber 2 is reheated in recupera-W` tors`35,36 and 37 whlch are located beneath [the furnace, below the Hoor lineof themill `1n which the furnace is erected.` ,a

The recuperators as shown, have rows of vertical air flues a ternating with rows of horizontal fines 39" for the waste sby `which the airis reheated. There ractory s llues are plates 40, the plates havin an opening 41in `register witheach vertica iiue 38 through `which the air tobeheated enters the vertical air iiues 38 from thelair tunnels 42 below the `base-plates.1 l i The fiues 38 open `.at their upper ends into the clear spaces at the top of eac recuperator recuperators. The middle passage 44, as will be seen in Figuresl, 3 and 8, connects the i `middle recuperator 36 with a transverse lair passage 46,V which, `in turn, opensinto the lower ends of the vertical air ilues or uptakes w 33 that su ply preheated air to the lower section 16Mo the heatin tile 47, which is sli `abl `mounted in each uptake 33, islmanipulate through doorways 48 from the cross tunnel 49 serves to regulate e the volume of air supplied to each, uptake 33 e the chamber 2.`

and,`i`n this way, to regulate the` temperature `across thewidth of t e `A swinging door 50, normally in closed a position, isprovided on each ofthe doorways `The passages 43 and 45, at thetop of the end recuperators 35and 37, open into air y `flues 51 and` 52 which connect into'the lower ends `of thel vertical u `takes or `fiues 53 and 54` at the sides of the and the upper ends of these uptakes connect with the op` e posite ends of the transverse ilue 31 by which `preheated air is supplied through the` ports 30 to the upper section of the heating SUPPOlTted `011 `spaced beams 58 which, inturn, aresupported on cross-beams 59 that rest on chamber 2. ,e y y y y `The perforated metal base-plates 401`are piers 60, so as to form the air supply tunnels `42 and cold'air is su plied in re ated quantities to these tunne through t e air valves" l downwa i chamberwhich form passages 43, 44 and45 for the passage of the heated air from the r chamber 2. A loose lower section 16 "of y the charglng o Vcomes filled with the bloomsl or other matethe furnace.` a (See Figures 1 an 6.)

The waste ases or products of combustion Afrom t e soaking chamber 3 pass through the restricted opening or throat 4 n and \mix with'the heated gases in the upper sectlon `150i the chamber 2 and these gases traveltoward thecharging end of the furnace where they pass rfrom the heating chamber 2 through vertical waste gas ilues 63 at "the sides of the furnace into the horizontal glesM below the charging end of the cham-` The waste gases from-the lowersection 16 yof theheating chamber 2 travel to the charg- 1 ing end of thls chamber beneath the rows of metal su orted `on the skids 5 and ass y through vertical waste gas ues between vertical ilues 63. The fines 64 and 65 discharge the waste gases into `horizontal f iues 66 `which connect with one end of the upper half of thehorizontal waste gas ilues 39 in the recuperaters. l

The heated gases travel through approximately the upper one-third of thehorizontal rows of recuperator flues and pass into the chambers 67 at the opposite end of the recuperators where the gases are causedto 4flow in a reverse direction, through the middle one-third of the gas fines and into the chambers 68 at the other end of these dues where l the `direction of travel is again changed and the gases flow through the lower one-third of the `flues and into the ` chambers 69, 70, 71 which lead to the stack flues 72, 73 74. Each stackilue is rovidedwith a damper 75 to regulate the ow of? gases from the recuper- 'gators to the stack and there `is the usual stack flue 76, and main stack damper. n a In the operation' of my improved furnace fit first will be fired and the various series of burners l will'be regulated to provide for equable heating across the width of the up er and lower sections 15, 16 of the heating c amber 2 and the soaking chamber 3 of the furnace.

After the furnace and the recuperators lbecome sufficiently heated, charging of the blooms or other material will be started b successivl pushing single blooms through pening 13. `As the furnace bc-v rial to be heated, the heating chamber 2 is divided by the blooms into upper and lower sections 15 and 16, respectively, as has been i y12th described.-

s the blooms pass across the furnace hearth they graduall become heated and whilewithin the soa ing chamber 3 they reach the `desired rolling temperature and become uably heated throughout the mass of each bloom. Because the soakingchamw.. ber is fired with the aid of air at atmospheric or relatively low temperature, the intense flame temperatures obtained by the use of preheated air in the heating chamber 2 are not caused to play upon the now highly heated materials in the soaking chamber.

In this way the materials ma be held in the soakin chamber for consi erable time intervals uring delays in the removal of heated blooms from the furnacel without excessive scaling or other injury tothe heated materials, and the materialswill be maintained at a rollingftemperature in'readiness for immediate use when rolling is resumed. At the same time heating of the materialsin the heating chamber need `not be continued during such delays and in this way excessive scale losses are avoided andprevented.

After the furnace becomes filledV with blooms, the automatic discharge of a bloom from the gravity discharge opening 14 to the roller feed table 20'is effected each time a cold bloom is pushed into the charging end of the furnace. v

'lne burned gases from the soaking chamber 3 pass throughthe throat or restrictedV opening 4 into the heating chamber`2 where they mingle with the burned gases evolved in this chamber. s

The burned gases ypass from the furnace and through the recuperators 35, 36, 37 in traveling to the stack. The dampers 75 in the stack flues will be adjusted'at suitable intervals as required to regulate the heating of the recuperators and the flow of air and fuel also will be regulated to control the temperature of the upper and lower sections of the heating chamber 2 and the soaking chamber 3, as will be readily understood.

The many advantages of my invention will be apparent to those familiar lwith theqart. The use of separately and independently regulable heating and soaking chambers enables the high flame temperatures obtainable by the use of preheated air to' be' utilized without danger of overheating the blooms or other material within the furnace, and in this way save fuel and increase the capacity of the furnace.

The provision within the heating chamber adjacent its delivery end of upper and lower heating sections with the series of independently regulable burners in each section of the heating chamber enables the under side as well as the upper side of the blooms to be Vheated lnore rapidly and effectively than is otherwise possible.

The temperatures of the heating and soakin chambers can be varied and controlled at di erent points in the width of the furnace. By means of the downwardly extending wall between the heating ano soaking chambers the effect of radiant heat from the heating chamber does not affect the material in the soaking chamber and the fiow of the products of combustion from the soaking chamber can be sufficiently retarded to create a back pressure which will lessen and overcome infiltration of coldair into the soaking chamber through the gravity discharge outlet and other o nings in the side walls of the soaking cham er. By using preheated air in the heating chamber and air at a lower temperature in the soaking chamber, the blooms can be maintained within the soaking chamber at or close to the desired rolling temperature at all times and particularly when delays in the mill operations cause interruptions in the demand for heated materials.

The location of the independent series of burners at the delivery end of the heating chamber andthe delivery end of the soaking chamber enables irregularities in the heating operation ordinarily caused by variations in the quality of or quantity of fuel,

`Weather conditions and the like, to be readily overcome and the location of the hot spot7 in the furnace to be closely controlledand removed from a, point close-to the furnace discharge opening. The regulation and control of the temperature at different points in the length of the furnace enables a greater tonnage to be produced in a furnace of a given length. v

lBy the arrangement of separately and independently heated chambers shown, the desired quality or temperature and uniformity of heating is obtained in the sc `king chamber and the regulation as .to capacity 's controlled by the heating chamber. Many variations in the construction and operation ofthe furnace may be made. The use of-preheated air, although preferred, is

f not absolutely necessary in securing many of the advantages of my invention. The recuperators may be omitted or replaced by regenerators. The use of the lower independently` fired section ofthe heating chamber may be omitted and other chambers may be made without departing from my invention, as defined in theappended claims.

I claim:

'1. A continuous heating furnace comprislng an elongated heating chamber, burners in the rear end of said chamber adapted to provide large quantities of fuel and air so as to permit a rapid passage c7 the material being heated, a comparatively short soaking chamber to which the materlal passes from the heating chamber, said soaking chamber being separated from the heating chamber lby adivision wall extending from the top of the furnace downwardlyv and providing a relatively narrow passage between said chambers, and burners adapted to maintain the soaking chamber substantially at the temperature required in the discharged material, the heating chamber extending continuously from-the charging opening to the soaking chamber andV having an enlargement at its rear end only, the roof of the heating chamber being fiat so as to provide a uniform height across the width of the chamber.

2. A continuous heating furnace comprisheating chamber having a ad] acent one end thereof, amber adapted to provide ing an elongated charging openin burners in said c large quantities of fuel and air so as to per my hand.`

`end of t means adjacent the discharge end of mit a rapid passa e ofthe material being heated,l `a comparatlvely short soakinglohamber to which the material asses froml the heating* chamber, burnersa a ted to maintain, the soaking chamber su tantiall at ing a metalchargin openingadjacentone end, a `soaking cham r having a metal discharging opening ad'acent one end, a trans- -verse wall having a at lower face extendin downwardly toward the plane of travelo the metal being heated to form a vertically restricted passage connectin the abutting ends of the heating and soa 'ng chambers, y

lying means adjacent the discharge fuel sup e heating chamber, and fuel supplying n the shaking chamber the roof of the heat.

in chamber being fiat so as to provide a umform height across the width of the furnace and being in close proximity to the furnace hearth adjacent `the charging end of the furnace and being stepped upwardly intermediate the ends of the heating chamber to. form a high combustion section adroent the discharge end of the heating cham vIn testimony whereof, I have hereunto set ALBERT'L. oULBER'rsoN.

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