US2611601A

US2611601A - Vibrating-hearth furnace

Info

Publication number: US2611601A
Application number: US140659A
Authority: US
Inventors: Dee A Knight
Original assignee: Individual
Current assignee: Individual
Priority date: 1950-01-26
Filing date: 1950-01-26
Publication date: 1952-09-23
Anticipated expiration: 1969-09-23

Description

Sept. 23, 1952 D. A. KNIGHT VIBRATING-HEARTH FURNACE Filed Jan. 26, 1.950

3 Sheets-Sheet 1 IN V EN TOR.

ATTORNEY Sept. 23, 1952 KN|GHT 2,611,601

VIBRATING-HEARTH FURNACE Filed Jan. 26, 1.950 3 Sheets-Sheet 2 Fig. 3

g 4 INVENTOR.

ATTORNEY yDgE A227;

Sept. 23, 1952 D. A. KNIGHT VIBRATING-HEARTH FURNACE 5 Sheets-Sheet 3 Filed Jan. 26, 1.950

Fig.6

INVENTOR. DEE A. KNIGHT ATTORNEY Patented Sept. 23, 1952 UNITED STATES PATENT 2,611,601 Q i i VIBRATING-HEARTH FURNACE Dee A. Knight, Lawson, Colo,

Application January 26, 1950, Serial No. 140,659

This invention relates to furnaces of reverberatory type adapted for the heat treating of various materials for diverse particular purposes and hasas a primary object the provision of animproved such furnace adapted and arranged'ior automatically continuous treatment of a material flow therethrough as distinguished from intermittent or batch operation.

A'further object of the invention is to provide improved means for automatically feeding material under heat treatment along and across the heat-exposed hearth of a reverberatory furnace.

A further objectof the invention is to provide improved meansautomatically operable to effect feed of material under heat treatment along and across the heat exposed hearth of a reverberatory furnace andselectively adjustable to regulate and vary the rate of such feed throughout a range appropriate for materials of varying form, nature, and densities.

' A further object of the invention is to provide improved means for automatically and continuously discharging treated material from a continuous-type reverberatory furnace.

A further object of the invention is to provide improved means for automatically and continuously feeding material to be treated to and ,for translation through a continuous-type reverberatory furnace.

A further object of the inventionis to provide improved means for preheating incoming feed material as an incident of its automatically continuous delivery to and within a continuous-type reverberatory furnace.

A further object of the invention is to provide a vibrating, material-translating hearth in operative association within and in effective exposure to-the heat circuit of a reverberatory furnace.

A further object'of the invention is'to provide an improved construction of and selectivelyadjustable operative mounting for a vibrating, material-translating hearth in a reverberatory furnace.

' With the foregoing and other objects in view, my invention} consists in the construction, arrangement, and combination of elements as here-1 inafter set forth, pointed out in my claims, and illustrated by the accompanying drawings, in which:

Figure 1 is a side elevation of a typical reverberatory furnace as equipped and arranged to give effect to the principles of the invention, certain adjuncts being shown in broken lines and a portion of the stack being broken away to con- 4 Claims. (01.263-21) serve space. Figure 2 is a front end elevation of the installation according to Figlile '1, an up per portion of the structure being broken away to conserve space. Figure 3 is a vertical section,-

on an enlarged scale, taken longitudinally of the installation on substantially the indicated line 3-3' of Fi ure 2 with certain elements broken away to conserve space. Figure 4' is a horizon tal section through and on substantially the in:- dicated line 4-4 orFigure 3. Fi ure 5 is a trans verse section taken substantially on the indicated line '55 of Figure '3. Fi ure 6 is a fragmentary, detail section, on a further enlarged scale, taken substantially on th indicated line 6-6 of Fig ure 3. Figure '7 is a fragmentary, detail section, on the same scale as Figure 6, taken substantially on the indicated line 7-1 or'Figure '3. Figure 8 is a fragmentary, detail section, on the same scale as Figure 6, taken substantially on the indioated line 3- 8 of Figure 1;

Reverberatory furnaces of the general type disclosed in my copending' application for patent of the United States, Serial No. 109,020, Series of HMS/are extensively in usefor the heat treating of a variety of materialsincluding minerals, organic 'food products} chemical compounds, and thelike, to variously effect roasting, drying, dehydrating,' sintering, expanding, and exfoliating thereof. Such furnaces arecharacterized by a chamber enclosing a hearth, a source of heat discharging within the chamber, and a heat travel path or circuit traversing upper and lower faces of the hearth for appropriate temperature elevation of a charge upon the hearth. Conventional furnaces of the type noted are generally adapted for intermittent or batch operation witha consequent limitation of their ciliciency and availability for the treatment of certain materials, and it is to the provision of a vibrating hearth in association with such a fur-- nace and operable to translate material under treatment continuously through such furnace that the instant invention is primarily directed.

In the drawings, a typical reverberatory .furnace is illustrated as a generally rectangular, closed chamber comprised from rigidly interrelated sidewalls Ill, rear .end' wall ll; front end wall 12, roof l3, and floor M. The sides, end walls, and. roof may be of any desired heat-resisting construction appropriate to withstand the temperatures developed interiorlyof'the chamber, the illustrated constructiontypifying the use of spacedly-parallel, inner and outer metal shells constituting the furnace sides, end walls, and roof in an arrangement providing for circulation of cooling fluid between the shells or for heatinsulation of the chamber by means of suitable material charged within and filling the space between the shells. Whatever may be the particular furnace wall and roof construction employed, the said walls close against a rigid, suitably-supported imperforate floor conveniently constituted from a metal sheet or panel. Giving operative effect to the principles of a reverberatory furnace arranged to heat both upper and lower surfaces of a hearth therein, a flue I5 opens through a lower port-ion of the furnace rear wall II and communicates with a stack IS in a manner to exhaust heat and products of combustion from the furnace chamber and through said stack, while burners H, or equivalent sources of high temperature gas flow, are mounted in and for delivery through an upper portion of the chamber front wall I2, so that, a hearth memher being provided longitudinally of the chamber in end-spaced relation with the front wall I 2 and to substantially close against the rear wall I I above the flue I5, a flow path or circuit for the high temperature emanations from the elements I! is established within the chamber and longitudinally of the hearth upper and lower surfaces. In the treatment of certain materials, it is Wholly. expedient'that the high temperature supply to the furnace be developed through direct combustion within the furnace chamber of fuel products deliveredthrough the elements I1, as is the case when said elements or burners are fed by hydrocarbon fuels, combustible gases, powdered coal, and the like while in the treatment ofcertain other materials impingement of flame and products of combustion against the material under treatment is to be avoided, in which case-the elcments ,I"! may typify input nozzles for the delivery of previously-heated,

high temperature air and gas streamsto and interiorly of the furnace chamber. a V. i

All of the foregoing is largely conventional practice and merely typical of a furnace operative'arrangement wherein and wherewith the improvements hereinafter described are effectively and advantageously employable.

In accordance with and togive effect to the I principles of the instant-invention, a hearth I8,

preferably and conveniently in the form of va flat, shallow, metal tray having. upstanding long magin flanges and of appropriate size, is operatively mounted longitudinally of the furnace chamber in spaced relation of its forward end rearwardly from, the chamber front wall I2, in close adjacency of its rearward end relative to the chamber rear wall II, and in clearing relation of its long side margins relative to the'chamher side walls I9. The hearth I8 is designed to Vibrate within and relative tothe furnace chambar, to which end a shaft I9 is engaged transversely beneath and to support the midlength of said hearth and is extended at its ends perpendicularly through the chamber side walls 10 and exteriorly of said side walls through collars 20 carried by. the lower ends of hangerassemblies 2|, hereinafter more particularly described. To accommodate vibratory play of the shaft I9 relative to the chamber side walls In without extension of vibration tosaid side walls, the side wall apertures accommodating, the shaft are somewhat" largerthan the, shaft itself, as is clearlyshown in Figure '7, and plates .22 fixed toand radially of the shaft 19 in appropriate size slidably close over the shaft-accommodating apertures in bearing engagement against'th inher and outer faces of the intersected chamber side wall to minimize heat outflow from the chamber about the shaft ends. The hanger assemblies 2I supporting the shaft are identical and each thereof comprises a threaded stem 23 adjustably engaging through an outer end of a bracket 24 fixed to and projecting laterally from the side wall Ii! upper margin, a turnbuckle 25 included in and for length adjustment of the stem 23, a vibration-absorbing,unit 26,.of any desired particular construction, on the lower end of and extending the length of said stem 23, and an eye 2'! linking the lower end of each unit 26 with the adjacent shaft-supporting collar 29. As is readily apparent, provision of the hanger assembly ZI 'in the form and construction shown and described serves to effectively support the shaft I9 through and relative to the furnace chamber in a manner permitting of shaft and hearth limited oscillation relative to said chamber and adjustment of the shaft end positions within the range of the clearance between the shaft and its accommodating apertures through the chamber Walls. Manifestly, to develop the desired heat circuit within the furnace chamber, the shaft I9 ispositioned to dispose the hearth I8 somewhat above the flue I5 intersection withthe chamber rear wall I I. Y Y

To further support the hearth I8 and to determine the operating attitude of said hearth longitudinally of the furnace chamber, a shaft 28 is engaged beneath and inwardly adjacent each end of said hearth to traverse the furnace chamber in spaced parallelism with the shaft I9, each of the shafts 28 being extended at each end to intersection of the chamber side walls I0 through vertically-elongate, arcuate slots 29 whereof the center of curvature is coincident withthe axis of the shaft I9. The slots 29 preferably extend above and below the horizontal plane including the axis of theshaft I9 and are of such altitudinal extent as may be appropriate or desired for angular adjustment of the hearth I8 in any given installation, and suitablyarouate plates 3E] fixed to the shafts 28 in slidably bearing engagement with the inner and outer faces of the chamber walls intersected by said slots are disposed to reciprocate in clips 3| fixed to the chamber wall faces and thereby close the slots 29 against heat escape therethrough. Outer ends of the shafts 28 engage-with and through collars 28 on the ends of hanger-assemblies 2| depending in fixed, adjustable relation from brackets 24 in the manner previously described, thus mounting the shafts 28 for oscillation to gether with the hearth I8 and shaft I9 in a clearance of the shafts 28 relative to their slots 29 adequate to accommodate a desired oscillatory range. Provision of the arcuate slots 29- to accommodate the shafts 28in their intersection of the chamber side walls Icandsupport, of the shaft 28 exterior ends by the hanger assemblies 2I permits selective elevation ofeither end of the hearth I9 to dispose said hearth at an angular inclination to the horizontal longitudinally of the furnace chamber, as is clearly indicated by broken lines in Figure 3. Thus, the hanger-assemblies-Zi at the forward end of the furnace chamber may be shortened to lift the forward end'of the hearth I8 and to tilt said hearth-about the axis of the shaft I9 when and as the hanger assemblies supporting the shaft 28 at the rearward end of the hearth are correspondingly lengthened; such adjustment elevating the hearth forward end and depressing the hearth.

rearward end'in an angular relation with the horizontal wherein the heart-hassembly is free to oscillate. Conversely, the hanger assemblies supporting the rearward shaft 28 maybe shortened and the assemblies supportingthe forward shaft 23 correspondingly lengthened to. longitudinally tilt .the' hearth in an elevationof its rearward end and :a corresponding depression of. its forwardzvend while retaining the oscillatory char acter of the assembly. I I A :Suspended. interiorly of the furnace chamber in the-manner shown and described,- the hearth I8 is mounted for oscillation altitudinally and longi tudinally of said chamber within the limits imposed by the size of the side wall apertures accommodating the shaftsle and '28 and in any of its angularlyeadjusted' positions, and a periodic oscillation on the order of .a vibrationis imparted to said hearth during operation of the furnace through the agency of vibrator units or mechanisms 32, of any appropriate construction and type,.fixedly base-mounted exteriorly. and adjacent the side. walls of the furnace inoperativeengagement-with ends of the shaft I9 extending beyondthe shaft-associated collars 20. The vibrator-units 32 are conventionally shown in a representationtypical of such'instrumentalities adaptedfor electrical mechanicaLor pneumatic powerin and forregulation of thelength and intensity of their reciprocatory stroke, such units being known and available, and a practical and feasible association of such units withtheshaft I3is developedthrough a mounting of theunit's radially of the shaft and at a forward and upward inclination to the horizonta1such as serves through engagement of the unit reciprocableelement ends with said shaft to move the shaft I9,

and the hearth I3 carried thereby, upwardly and forwardly of the furnace chamber as-a conse quence'of unit 3 2;extension,-or outward stroke, andto move said shaft and hearth downwardly andrearwardly of the chamber as a c onsequenee of unit 32 contraction, or inward strokeisuchlon gitudinal oscillation of the hearth operating to induce translation'ofgranular material charged onto the hearth upper surface from the rearward and to the forward end thereof. The motion imparted to the hearth I8 through the agency of the units 32 is a rapid, cyclic, short-travel vibration operable to spread and agitatea granular charge on said hearth as well as to translate the charge along the hearth, and adjustment of the hearth longitudinal attitude, as above explained, supplements the adjustability of theunit'32 stroketo permit regulation of the rate of materialiravel r;

along'the hearth, so that, through the accelerating. or retarding influence of gravity resulting from hearth inclination, various materials may be caused to travel across the hearth length at a rate appropriate to develop the desired degree of materia1 exposure while on the hearth, and with the hearth transverse aspect maintained horizontal, the so-transl-ated material is caused to spread evenly in a state of constant agitation across the hearth width as it travels from end to end thereof.

Feed of material to be treated to the rearward end of the hearth I8 is conveniently had through a slit opening transversely of the roof I3 inwardly adjacent the furnace rear end wall I I in operative registration with the open lower end of a jacketed stack 33 upstanding from and above said roof, the upper end of said stack 33 communicating through a flue 34, furnished with a damper 35, with the exhaust stack I6 for the selective bypassing of hot gases from the furnace chamber 6 through the stack'3'3'; The material to be treated maybe introduce'dinto and for Jgravity drop through the stack 33 in anymanner and by( any means suited tothe character of a given material, an effective and generally-appropriate:ar rangement for such purpose being illustrated as a feed plate 33 s'lidably reciprocable in a horizontal disposition intersecting one wall of the stack 33wit'h its inner lip interiorly overhanging the stack passage, a vibrator unit 3l,the same as or functionally analogous to the units 32, mounted upon the furnace roof I3 and operatively engaging theplate 36 to vibrate the latter for travel of granular material thereover'and from the'o'uter to the inner areas. thereof, and means, such as'a hopper 38, for supply of material to therplate36- outer area; The dischargethroat of, the stack 33; opens interi-orly of the furnace chamber against a bafile' 39 closing. against the roof I3 at the forward margin of the stack throat and inclining'rearwardly and downwardly of the chamber with its lower margin spaced forwardly from the furnace rear end wall I I. The baffle 39 serves to deflect material incoming through the stack 33 toward the furnace rear end wall, tolsomewhat retardthe free fall of the incoming material, to direct heatemanating I from the elements I1 downwardly toward the rear end of the hearth I8 an 1 to partially obstruct the, entrance of'hot gases within and for travel through the stack 33. As will be apparent, manipulation of the damper 35 may be had to permit a controlled flow of hotv gases from the furnace chamber and through the stack 33 for the preheating of material fed through saidstack; such preheating of the material being of significance incertain operations and operating to reducethe effective time of material transit across the hearth 18. Fixed to the furnace rear end wall II in spaced relation with and beneath the free lower "margin of th baffle, 39,

a second bafile 40 outstands in a forward and downward inclination to overhangthe rearward end of the hearth I8 and direct the material feed qnto said hearth without loss of material between the hearth rear end and adjacent furnace end wall. I

Material heat treated upon and translated longitudinally along the hearth I8 asa consequence of hearth vibration passes over the forwardend of said hearth and falls throughthe space between the hearth forward end andfurnace front liver the treated -materiallexteriorlyof the fur-'- nace 1 chamber. wManifestly,-. diverse; variouslypowered structural organizations may'be utilized to effect delivery of treated material from: the fur nace chamber, the particular such ill-us trated and hereinafter described being'buttypical' end, said trough having a length exceeding the furnace chamber width and reciprocably intersecting the furnace side walls II! in end extension therebeyond at such longitudinal inclination relative to the horizontal as may be appropriate in a given installation. The trough 4| is supported and suspended for longitudinal oscillation by means of links 42 operatively engaging between trough zones exteriorly adjacent the furnace side walls I0 and brackets fixedly carried by said walls above the trough, and a vibrator unit 43' basemounted exteriorly of the furnace in appropriate alignment with and adjacent one end of the trough 41 engages with the latter for continuous, cyclic, longitudinal vibration or oscillation of said trough as a consequence of unit 43 actuation; the trough 4| mounting and association with the unit 43 naturally being such as to apply trough vibration to translation of collected material along said trough and to delivery outwardly of the furnace through the trough end remote from the unit.

-It is to be noted that the improvement illustrated and hereinabove elaborated provides an eflicient, highly-adaptable, heat-treating furnace of reverberatory type wherein high temperatures of combustion may be either directly or indirectly applied both above and below a charge received upon and continuously travelling along a vibrating hearth in a manner permitting of continuous delivery of treated material from the furnace. The provision of an overhead feed to the furnace hearth through a stack functioning as a bypass for a portion of the furnace heat charge enhances the efficiency and steps up the effective capacity of the furnace, the angular adjustability of the hearth and the regulability of the associated vibrator units permit simple and effective control of the material flow rate through the furnace, and the construction and interassociation of elements comprising the improved organization conduce to uninterrupted service, simple maintenance, and expeditious repair.

Since many changes, variations, and modifica tions in the form, construction, and arrangement of the elements shown and described may be had without departing from the spirit of my invention, I wish to be understood as being limited solely by the scope of the append-ed claims, rather than by any details of the illustrative showing and foregoing description.

I claim as my invention:

1. In a reverberatory-type furnace having an enclosed furnace chamber defined by front, rear and side walls and a roof bridging therebetween, an exhaust passage through a lower portion of the chamber rear wall, heat-generating means delivering to said chamber through an upper portion of the chamber front wall, and means for feeding material to be treated through said roof inwardly adjacent said rear wall, a horizontal shaft loosely traversing the chamber side walls transversely of the chamber between the exhaust passage and heat delivery levels and well forwardly from said rear'wall, altitudinally-adjustable hangers engagingthe ends of said shaft exteriorly of the chamber to suspend the shaft for oscillation, vibrator units operatively engaging the exterior ends of the so-suspended shaft, a fiat,

solid tray fixed to said shaft in operatively clearing adjacency of its side and rear end margins relative to the corresponding chamber walls with its front margin spaced inwardly from the chamber front wall, whereby to dispose said tray as-ahearth positioned to'receive the feed of material at its rearward end and arranged to direct heat now within the chamber through the material infeed and to successively and longitudinally traverse the tray upper and lower surfaces, means for adjustably determining the longitudinal inclination of said tray relative to the horizontal, and means for collecting material discharged over the tray front margin and delivering the same'exteriorly of the chamber.

2. The organization according to claim 1, wherein said shaft carries radial plates disposed to slidably close over inner and outer ends of the shaft-accommodating openings through the chamber side walls.

3. The organization according to claim 1, wherein the means 'for adjustably determining the longitudinal inclination of the tray relative to the horizontal comprises supplementary shafts spacedly paralleling'and on opposite sides of said first shaft engaged beneath and adjacent the front and rear ends of the tray in loosely-intersecting relation with the chamber side walls, vertically-elongated, arcuate slots in the chamber side walls for the loose accommodation of the supplementary shaft ends, radial plates on said supplementary shafts disposed to slidably close over inner and outer areas of said slots, and altitudinally-adjustable hangers swingably engaging ends of said supplementary shafts exteriorly of the chamber.

4. The organization according to claim 1, wherein said exhaust passage connects with an exhaust stack exteriorly of the'chamber, a bypass fiue connects the chamber interior with said stack through the material-feeding means operable through the chamber roof, and a bafile in said flue is operable to regulate material-preheating outflow therethrough.

' DEE A. KNIGHT.

REFERENCES CITED The following references are of record in the file of this patent:

I UNITED STATES"PATENTS Numb 81