US1599165A - Intermittently-fired furnace - Google Patents

Description

Sept. 7 192s. l 1,599,165

H.H.vc:| ARK INTERMITTENTLY FIRED FURNACE Filfed May e, 1922 sept. 7 41926.` 1,599,165

H. H. CLARK INTERMITTENTLY l FIRED FURNACE Filed May e. 1922 5 sheets-sheet 2 Sept. 7,1926. 1 1,599,165

H. H. CLARK INTERMITTENTL'Y FIRED FURNACE Filed May 6. l1922 Y 5 Sheets-Sheet 3 @MMM/@wfg Sept; 7 1926.-

' l H. H. CLARK INTERMITTENTLY FIRED FURNACE A Filed May 6. 1922 5 Sheets-Sheet 4 l s w Sept. 7 1926. 1,599,165

v H. H. CLARK INTERMITTENTLY FIRED FURNACE Filed May e. 1922 5 sheets-sheet 5 Patented-Sept. 7, 192,6..

Homer: H. cLAnx, oF OAK 15mm-ILLINOIS.

INTRMITTENTLY-IRD FURNACE.

Application med May 6,

` chamber which receives thegoo-dsto be heat treated, and, for the sake of avoiding ill effects of continued combustion during heat treatment, combustion is interrupted and the heating' chamber is purged 'largely vof products of combustion before each 'charge of goods is introduced, and heat stored in the walls-of the chamber during the interval of combustion is given off to the goods durin the interval of heat treatment, andY the reatively immobile and inert furnace atmosphere can be maintained during the lastnamed intervals.

Eorthe sake of economy in time and heat consumption in the operation of a furnace of this type,-it isvery desirable to be able to change from the heating interval tothe charging interval with the utmostr promptness, Without residual combustion or unconsumed fuelmixture; also to return from the heat treatment interval to the combustion or heat storing interval with utmost promptness, either as an immediate sequence tothe removal of the charge of goods, or .preferably through automatic 'restoration of combustion whenever the temperature of the chamber falls to apredetermined degree, and provided the charge of goods is absent -from the heating chamber; and one object ofthe present invention isftopro'vidve 'firing apparatus which willinsure these conditions y in the furnace operation.

Accordingly, one feature of the present invention consistsin providing a lfurnace of v the class, described with burners adapted to supply fuel in Huid form along with an oxidizing agent, in such close proportions as will insure complete combustion, together with means for initiating and arresting the fiow of fuel mixture through the burners instantly as theconditions demand;v means being provided for.` coordinating the fuel,

controlling meansl and the flue controlling damper of the furnace in a manner to open the latter simultaneously with the initiation ofcombustion, and to close the same as combustion is arrested'. A feature incident to the'preferred embodiment of this part of the 1922. SerialV No. 559,108..

invention consists in utilizing burners of suchcharacter that immediately the flow of fuel is arrested, `residual fuel V,Within the burner will be at once consumed, as, for instance, by'so-called back firing, so that there iis no residual combustion taking place in the chamber, and the latter can bev opened immediately Afor purging and introduction ofthe goods. Another feature incident to 4the preferred embodiment of this part of the invention consists in the provision of combustion chambers between the discharge ends of the burners and the heating chamber so that ignition and oxidation are practically complete beforethe gases leave the combustion chambers, and products of combustion alone circulate inthe heating chamber. Another object of the present invention is to insure prompt and uniform distribution of heat throughout the Walls of the heating chamber; and to this.end, another feature of 4the invention consists in arranging the burners as a plurality of units Adistributed along the sides of the furnace and discharging their-products of combustion across the bottom of the heating chamber through tunnels constructed transversely of the piers that support the goods, and into impingement against the Walls of the chamber opposite the burner; the burners on o posite sides of the furnace and the tunnels through Which they discharge, being alternated in `position so that a burner on one side discharges its hot gasesbetween the lines of two opposite burners, and the gases are thus distributed uniformly an-d in rising columns -J nlp along the opposite inner'walls of the cf1 amber and across the roof to the escape Another object of the present invention is to so construct the inner Walls of the heating chamber in an intermittently fired furnace, that the area through which the walls alternately absorb and radiate heat will be greatly enlarged in proportion to the caacity of the heating chamber. Accordingy, another feature of the present invention consists in constructing the inner Wall of the 4heating chamberwith recesses, pockets,

grooves, cliannel's, or the like, all With an internal chamber that develops inner superficial heat absorbing areas-communicating with .the heating chamber through the medium of such recesses, apertures, or the like,

chamber through means of recesses,

vfuel and simultaneously actuating -the flue damper, controlling the circuits of this motor by a limiting pyrometer, and introducing into the controlling circuit a circuit closer that is responsive to the presence, on

\the outside of the furnace, of :track-bar or other means through which the goods are conveyed into and out of the furnace.

In order that the invention may be fully understood, the preferred embodiment of the several features thereof is shown in the accompanying drawings, in which Figure y1 is a side elevation of a furnace equipped with certain of the 'features of the invention.

Figure 2 is a front elevation of the same.

Figure 3 is a horizontal section of the same on the line 3X-3X of Figures 1 and 2.

Figure 4 is a vertical transverse section on the line 4X X of Fi ures 1 and 3.

Figures 5, 6, and are detail perspective views showing dierent constructions of channelled, grooved, or recessed inner walls of a heating chamber.

Figures 8 and 9 are fragmentary views showing, respectively, in vertical transverse section and in elevation, a construction of false inner wall adapted to develop with the main inner wall of the heating chamber an interior space connected with the heating apertures, or the like, in order to still further enlarge the heat-absorbing areas.

Figure 10 is a schematic view showing an electrical installation suitable for controlling the combustion by a pyrometer, and subjecting such control to the location of the vehicle which accompanies the goods into and out of the heating chamber.

Figure 11 is a detail view of a circuit closing switch suitable for use in the installation illustrated in Figure 10.

1 represents a furnace, which may be of known construction, 2 the door thereof, and 3 counterbalances .controlling the door through the medium of flexible connectors 4 passing over pulleys 5. 6 represents a damper adapted to control the'escape flue 6a which communicates with the uptake 6b through which products of combustion escape; and this damper 6 is oo itrolled by flexible connector 7 passing over pulley 8 to a counterbalance 9. 10 represents burners introduced horizontally through the sides of the furnace at a level slightly above the bottom of the heating chamber, as hereinafter explained, and in 'such positions on the opposite sides of the furnace that the burners on one side alternate the lines of their discharge with the burners on the other side. Each burner 10 is provided with a known construction of fuel mixing attachment 11 which has 'the function of intermingling with the gaseous fuel with substantial exactness thel quantity of oxidizing medium (in the present instance air) required for complete oxidation of the fuel, so that ignition can be renderedI substan tially complete within a very short distance of the end of the -burner and substantially before the gases enter the heatin chamber, as,y hereinafter explained. Each uel conditioning device .11 is supplied with fuel through a branch pipe l2 leading from a. gas main 13; and each branch pipe 12 has a controlling valve 14 through means of which to regulate the fuel apportioned to,

the respective burners, and closing the supply main 13, and through tality, the burners may so that by opening of fuel through the a single instrumenbe collectively controlled, and each will perform in exact ac- 'cordanee with its individual adjustment.

The burners collectively will thus insure proper distribution of heat units throughout the heating chamber.

As will be'seen upon reference to Figure 2,- the mains 13 on the res ective sides of the furnace, are connected t rough a crossover pipe 13 so that a single fuel control may serve for both groups of burners. As a means for supplying and arrestin fuel in the main'l, a valve 15 is employed, and this valve is controlled in common with the damper 6 through theYI medium of an arm 16 which is connected with,the sheave 8 at 17, and with the valve 15 through the medium of an arm 18. l19 represents a connecting element intended to lead to any point of control which may be manual, as when the operatives watch a reading pyrometer and turn on and off the gas at the proper interquence of the presence of hot surfaces with which the fuel. mixture contacts, as hereinafter described.

Referring to the automatic pyrometer control for the valve 15 and damper 6, as shown in Figure 10, 20 'represents a lever pivoted at 21,v connected atone end Ito the rod 19 and at its other endto a rack-bar 22 which receives the pinion 23 of a reversible v electric motor 24. 25`frepresents a pyrometer that current is supplied to the motor in one direction or the other as the arm 26 reaches.

a contact, and according V- to the particular contact which it reaches. To render the circuit 31, 31a inoperative so long as goods are in the heating chamber of furnace 1, the con ductors of said circuit are so involved with the circuit closer 34, lying in the path of the7 rack-bars 35 which serve as a vehicle for the introduction of .he goods into theffurnace, that so long as the rack-bars are in the furnace, whither theyare introduced by the conventional charging fork 36 pivotally mounted on truck wheels 37, the circuit closer 34 will be open and motor 24 cannot act to shift the lever 19 of the heating apparatus. But whenever the rack-bars 35. are out of the furnace and resting upon the circuit closers 34, the circuit; 31, 31a will be operative to energize the motor 24 whenever the thermo-couple 29 moves the contact -26 to either of the terminals 27, 28.

suitable Iconstruction Y may be ern-y An ployed' for kthe circuit closer 34. According to Figure 11, this mayv consist of a framelike member 34 pivoted at 38, held normally elevated by spring 39 to a plane above that to which it will be depressed by the rack- Irack-bars rest upon bars 35, and having resilient terminal 31x depressed upon contact 315' whenever the the frame 34.

In order to control combustion and insure ignition upon release of fuel mixture from the burners 10, and discharge the gases into the heating chamber as completely oxidized products of combustion, combustion cham-` bers 40 are arranged between the discharge ends of the-burners 1() and the heating cham' These combustion chambers consist of .thimbles or ue liners of highly refractory material adapted to store sutiicient heat fromoneperiod Ofcombustion to ignite the fuel mixture when it is released for an ensuing tion. In alignment with each combustion chamber 40 is a tunnel 42 formed through a `series of piers 43 upon which the rack-bars 35 rest while supporting the goods within the chamber 41, and these tunnels extend nreferablv to the opposite wall of the heatlperiod of coinbus-l `tured, as, for instance,

ing chamber, tunnels as already described being located on alternating lines so that the main body of hot gas or products of combustion from each burner passes across the opposite Wall and arises thence in close impingement against the Walls and against the roof of the chamber until it escapes throughthe uptake 6b into the flue 6a and past the damper 6, as alreadydescribed. Of course, appreciable portions of the hot gases by reason of their expansion will rise between the piers and circulate in the main space of the chamber 41, but the directing andimpinging action of the burners described will insure high efficiency vin heat transferring contact bet-ween the gases and the walls of the chamber. v

In order to enlarge the absorption capacity of the wallsl of the chamber 41,;they are, as already stated, provided with some form ofchannel, groove, recess, pocket, or

the burners and their aligned i the like which greatly `increases the supericial heat absorbing area. One form of wall construction having this result is shown in Figure 5, wherein 44 represents vertical ribs or pilastersl merged into sealing ribs or archesrand develop between them vertical flue like channels 45 tluough which the gases will iow in reaching the uptake 6". These structural members 44l obviously increase the superficialV heat absorbing area of the heating chamber walls to an extent represented by their dimension perpendicular to the wall, multiplied by their total length,`

which obviously will provide a very substantial increment in the heat absorbing surface,

According to Figure 6, horizontal ribs or ledges 44 are provided in a'manner to form horizontal grooves 45 l which' will vtrap the upwardly flowing impinging sheet of gases, andv by eddy currents cause impingement` thereof against the increased superficial areas provided.

According to Figure 7, the protruding( portions of the wall are in the form of limited-rectangular members 44b in the nature pf checker-work, leaving segregated pockets 45" among them in a' manner to affordan increment of superficial area at least c ual to that attained by theconstructions of ig-v ures 5 and 6. 1

When it is desired to get a very largel in' crease in heatabsorbing and radiating surface, as, is used for heating bodies of relatively large mass, for instance,- in the enameling of bath tubs, and the heating interval has to be continued for a proportionately longer time, I prefer to employ a lining or falsewall 46 in4 the chamber 41, with its area largely aperby lopenings 47,

for instance, where the. furnace` thereby providing a recess 4 8, the wa-lls of f surfaces, impingeme'nt against which byllthe and leave a -free opening for the inrush of hot gases is induced by the communication cold air between the closer, the motor circuit 31, 31a

' minal 28, motor 24 will be actuated in the dithrough the the charge of finished 4 moved and the circuit of the burners, and the main door 2 closed.

at proper y on the part -matically ensue.

piers 43 and the upof the recess 48 with the escape Hue 6, 6b. ward displacement and outHow of products of The liner or false wall 46 may be constructed combustion. Cutting off of the fuel mixture of frame-like tile, such, for instance, as ythe in the burners 10 results in immediate arrest tile commonly used to build mutlles in'enamof combustion because oxidation is practieling or annealing furnaces, but with the cally complete before the mixture leaves the thin panels of such tile wholly-removed in combustion chambers 40. Re-ignition, howorder to provide the openings 47. 't ever, will take place immediately upon res- In the operation of thetfurnace, thevalve torat-ion of the flow of'fuel mixture because 15 and the damper 6 will be iirst opened by of the heat stored up in the refractory liners hand, fuel mixture ignited at one or more 40. Even the fuel mixture contained in the conditioning devices 11 will be consumed at `the interruption of fuel supply, because the mixture is combustible at. the upper ends of bustion chambers 40` until the inner Walls of these devices and back firing will result as the furnace have absorbed sufficient temperasoon as the momentum of fuel mixture is ture, Whenvthe furnace can be left to autoarrested.A f matic heat control, which will shut the valve I claim: t 15 and damper 6. The goods are arranged l. furnace for subjecting materials to upon the rack-bars 35 (Figure 10), the furheat underinert environment, comprising a nace door 2 is opened, the rack-bars contain- Closed chamber in which the materials are ing the goods are introduced through means heated, a plurality of fuel burners havin of conventional fork 36, .the fork is withi air-tight connection with and delivering drawn, and the door 2 is closed. The goods products of combustion into said chamber, will be permitted to remain for a time inand a master control for all of said burners terval predetermined by experience, when adapted to completely arrest and re-establish the door 2 is opened and the goods drawn. Assoon as one or more of the 35 rest upon the frame 34 lof the circuit to ire-ignite fuel When restored thereto.

Will be closed 2. In an intermittently Hred furnace for so that if the arm 26 of the pyrometer 25 has subjecting ,materials to heat under inert enin the meantime moved into contact with tervironrnent, a plurality of burners, a closed heating chamber with which said burners rection to open thek valve 15 and Hue 6 and have air-tight connection, connections for restore combustion: Under ordinary condisupplying said burners with a mixture of tions, with theeiciency of the burner and fuel and oxidizing medium for said fuel, hot gas distribution herein described, temsaid burners having ignition combustion perature -will be restored and arm 26 will chambers which deliver products of coinmoveto contact' `27 and close the circuit bustion to said furnace; and a furnace tem- `motor 24 in the direction to ar-v perature actuated single master control rest the fuel and close the damper 6 while adapted to completely arrest and release goods isV being refuel to said burners.' movedl from the rack-bars 35 and a new 3. ln an intermittently fired furnace for charge of goods to be baked arranged theresubjecting materials to heat under inert enon. In thls way' the vfurnace will 4be kept .vironment a closed heating chamber, a plutemperature without attention rality of burners Htted air tight into the of the operatives. wall of `the furnace and having ignition chambers adapted to ignite fuel delivered If at any time the goods should'be left 1n the furnace until the temperature .drops thereto and through which the respective burners deliver into the interior of the heatbelow the point` developing contact between arm 26 and low temperature terminal 28, the ling chamber, means for delivering fuel to lgnition cannot be restored because of the the burners, means for automatically mixa sence of the rack-bar 35 over the circuit ing air with the fuel so delivered, in adv closer 34; but as soon Combustion will then proceed at allthe burners and will restrict itself to the comv closerv 34is depressed bers, a furnace-temperatu'rev actuated master by the presence of a rack-bar thereon, restovfuel supply valve opening -and closing to ration of furnacetemperature willauto- Supply and' completely interrupt How of fuel, a Hue cutoff, and means connecting said Hue cutoff and fuel supply valve to enforce opening and closing of the same in `\unison. v

4. In an intermittently fired furnace for Scavenging orr purgingthe heating chamber 41 of products of combustion results automatically fromraising of the door 2 which, as suggested by the dotted outline of the heating chamber in Figure '-2, will arise subjecting materials to heat under inert enas the goods are revVance of its discharge intorthe ignition chamabove the crest of the crown of the arch vironment, a plurality of fuel burners having ignition chambers with which said burners have air tight connection and through which they deliver burning gases, enclosed heating chamber receiving said gases from said ignition chambers, and a master fuel sup ly control for all of said burners adapte' to com letely arrest and restore su ply of fuel t creto; said ignition cham ers being constructed with ignition liners that store heat above the ignition point of the fuel and cause re-ignition of the master control.

y 5. In a furnace .for subjecting materials to heat under inert environment, a heating chamber, a fuel supply for said heating chamber, an electric motor adapted to control said fuel supply, circuits for said motor, a yrometer controlling said circuits, meansor charging materials to be treated,

into the furnace, and a circuit closer also controlling said circuits and which is in turn controlled by the' furnace charging means.

6. In a heat treating furnace, furnace charging means adapted to assume positions eithervvithin or out of the furnace, burners for heating said furnace, means controlling thev operation of said burners and means whereby the control. of the burners is made dependent upon the position of the furnace -charging means. fuel. when restored to the burners 'by the 7,. In an intermittently operated furnace for subjecting materials to heat under inert enviroment, burners for heating the furnace,

fuel delivery controlling-means for said burners, and meanswhereby said .controlling means is rendered ineffective to deliver fuel While a charge ofmaterial is in the furnace.

Signed at Chicago, Illinois, this 29th day 40 of April, 1922.

HORACE H. CLARK.

Images