US1534488A - Multiple-unit hearth furnace - Google Patents

Description

April 21, 1925. 1,534,43

O. L. BARNEBEY MULTIPLE UNIT HEARTH FURNACE Filed May '7, 1921 2 Sheets-Sheet 1 INVENTOR Kl/d (Mm. an I HIT/VC'SSES Patented Apr. 21, 1925.

UNITED STATES Q Y 1,534,488 PATENT OFFICE.

. OSCAR L. BARNEBEY, or nn'rn-orr, MICHIGAN.

MULTIPLE-UNIT HEARTl-I FURNACE.

Application filed May 7, 1921. Serial No. 467,638.

Hearth Furnace, of which the following is aspecification. I

My invention relates to treating materials with heat to decompose the same or cause reaction of the same with gases, to change the decomposition?* of the materials or to effect some other desirable change. The fundamentals of my invention are to provide a unitary multiple hearth arrangement, and with such multiple hearths I accomplish ease of shipment, ease of assem bly, adaptability to expansion of furnace capacity, readiness of addition of other units and many points of convenience and economy in manufacture.

The sectional unit features of my invention are adaptable to various sizes and. forms of furnace construction, from small furnaces to very large ones. When the units are made of cast metal the advantages in casting are very great, most particularly where a large furnace. is tobe erected, in that casting the furnace in units can be very much more easily accomplished than making the entire furnace of a single casting. Such sections are more easily machined, more conveniently shipped, and more easily handled in erection.

One of the very desirable features accomplished by my invention is that additional capacity can be added to any particular furnace by simply adding more hearths, or if over capacity has been attained in any installation hearths may be removed should i such seem desirable in any particular case.

" A minimum amount of material is used, since the side walls are made of ordinary fire-brick construction. In some cases it is desirable to construct the contact wall of metal, in which, case such can be readily done. The unitscan be readily replaced by theuse of wickets appropriately spaced in the side or end walls of the furnace. Thus, when a hearth unit becomes non-serviceable by breakage, corrosion or any other cause, it can be removed and replaced without undergoing the very great expense of dismantling the furnace.

Added to the above my invention gives the bestpossible application of heat in that the heating gases are passed under the hearths and over the surfaces of the material being heated, the means for directing the flow of the gases being formed integral with the hearth. The heating means is so arranged to provide a combustion gas zone from which passages conduct the hot gases into the treating zone of the furnace, which contains the multiple unit hearths, such hearths dividing the furnace treating zone into many secondary compartments. The

number of passages or conduits for conducting the combustion gases into the treating zone may be varied at will to give the heat application desired, thus allowingthe introduction of a small or large amount of hot combustion gases at any particular point desired. The regulation of quantity of gas passing thru a particular passage orconduit is accomplished by meansof slabs or blocks of ceramic material, appropriately placed in the passageway, such blocks being movable to any angle or position desired, hence the slabs or blocks serve the purpose of dampers. Likewise in the same manner the gases from the treating zone of the furnace may be vented from any desired number of exit ports or passages.

Following my invention the material passes thru the furnace and over the multiple unit hearths by means of gravity, such movement being regulated in such a. manner as to give the time treatment desired. At the same time that the material is passing downward over the hearths, the hot combustion gases are passed under the hearths thru gas ports contained in thelower portion of the hearths and over the material supported on the hearths, the gas moving in the general upward direction. The downward movement of the material and the upward passage of the gas thus preheats'the material to treating temperature. At the same time the movement of the gas dilutes and sweeps out the gaseous products of reaction or distillation.

I provide continuous means for elevating material into the furnace hoppers, and by continuous removal of the treated material byscrew conveyors continuity of processing is maintained.

The material being treated is spread out by means of this invention into thin layers having la g surface areas exposed for heat treatment, reaction or decomposition. By using the inetho d of heating herein outlined an excellent control of intensity of heating and the quantity of treating gases is obtained. Likewise the 'preheatin'g of the material can be carried on as rapidly as desired, and at any rate required by tle proper regulation of the exit passages to the exit manifold.

One of the forms of my invention is illus trated in the accompanying drawings, in which Fig. 1 is a prospective view of one of any multiple unit hearths, 2 is a detailed view of a metal iositioning strip used in conjunction with the unit hearths, Fig. 3 is a vertical cross section of one of my furnaces using my multiple unit hearths, and Fig. 4: is a detail of inner furnace wall showing one of the combustion gas damper slabs.

Referring to the drawing, Figures 1 to 5: Fig. ,1 illustrates one of my multiple unit hearths in which 1 is a cast metal hearth which has projections 2 integrally cast at an appropriate angle. for instance 35 degrees 1n relation to the hearth. Such pro jections serve for support of an inclined hearth positioned in the side walls of the furnace. This angle of 35 degrees thus determines the angle of flow of materials over the hearth 1. The projections 2 have openings 3 into which pins or fiatstrips of metal 4 of F ig. 2 :project to position the hearth in the furnace. The projections are'of such length as to project thru the brick wall '13 of Fig. '3. The pins or strips at then fit snugly against the outer surface of the wall in that such pins consist of the lower portion 5 which passes thru 3 and the upper .portion 6 which rests on 2 abore 3. the flat surfaces thus giving outer support for the unit. The supports 7 arealso cast integral with the metal incline 1. These supports are the resting pins for the bottom of the hearth placed above each successive unit. On the upper surface of these supports the hearth which rests upon the same is free to move, thus allowing for contraction and expansion caused by heating and cooling with freedom, dbvia-tingr any physical strains being set up within the furnatte. Fig. 5 is a top section of the smallest part of such a support drawn to the same scale as in Fig. 1. The front plane 8 and the line 9 at the back indicate the construction features of the support, which allow the material to .pass by the support without lodgment.

The openings or gas ports 10 are also cast integral with "the inclinedhearth 1. These ports consist rectangular boxes with inclined roofs 11, the function of the ports being to allow the gas to pass thru the hearth and consequently past the material being treated, and from this particular construe tion to allow the material to fiOW uniformly from the same for a sufiicient distance to extend above the upper surfare of the layer of material being treated, and in this wise no material can fall thru the same. The upper portion of each of these gas ports is in the shape of an inverted V, thus it: which furnishesthe roof 1.1 of the port. This roof prevents lode'ment of material as it flows down the incline and guides the material into the openings 12, and from these the material. passes on down the incline to the next inclined hearth beneath.

The depth of layer of the material being heated is regulated by the distance between the lower end of the hearth and the side wall and the distance between the lower end of the hearth and the upper surface of the inclined hearth next beneath, in other words,.

by the height of the supports 8 of the in clined hearths which regulate this distance.

Fig. 3 is a side elevation in rross-section of a furnace constructed of my multiple unit hearths in which 13 is the tire-brick side wall which supports the units 1 by means of projections 2 which pass thru the wall 13, and positioned by the pins 1. The top extension 14; of the fire-brick wall 13 may be flat or an arch of fire-brick. The base 15 is of fire-brick construction maintained in position by common brick supports 16. The outer wall 17 is of sheet metal construction being bolted or riveted at 18 to the bottom and top connections 19 which project into the fire-brick work. Before the top connections are made the space between the fire-brick wall 13 and, the sheet metal exterior 1? is filled with a ,{LOOd insulating material 1'? such as sil-o-cel to conserve. the heat for the furnace.

Heat is supplied by burninggas, oil or similar fuel. In the drawings use of {ms is illustrated, the same passing; thru the manifold 20 already premixed with the correct amount of air to QiYG proper combustion. The quantity of premixed gas and air being: burned in the furnace is regulated by means of valves 21. The gas passes thru the restricted opening 22 and is burned upon the chip bed 23 and from theme the hot gases rise into the distributing zone 24. From 2+2 the hot gases pass thru the ports 25 into the furnace treating zone 26. The quantity of any gas allowed to enter thru any particular port is regulated by positioning the ceramic slabs 9.7. Other ports 28 are used to exit the gases from treating zone 26 into the flue 29 and other slabs 30 are positioned to allow the desired amount of gas to pass out of any one particular port. One or several of such exits may be used. The position and tightness of the fit of the slabs in ill) ion

pressure within the flue 29. This damper turned by means of the chain 33.

Openings 34: are positioned in the furnace to give ports of entry from the outside and thru which the slabs 27 and 30 can be moved into any desired position. This is accomplished with a rod or poker. The opening is cut thru the lire-brick work, and the metal pipes inserted thru the sil-o-cel and par tially thru the fire-brick wall. The cap 36 is threaded onto 28. The cap has the center cut out and a mica or glass sheet inserted to give a visual opening into the furnace. Thru the o ')ening 34 gases can be withdrawn for analysis, temperature readings can' be taken, in fact, these openings are convenient for many purposes.

Entrance ports 37 and similar pipes 38 and caps 39 also are used to give observation means to see the chip bed. This port also serves as a lighting port when the gas isfirst lighted in starting the heating of the furnace.

Thematerial enters the furnace thru hopper 40 and the treated material is removed by means of the spiral conveyor 41 revolving in tube 42. The tube 42 serves as a cooler for discharged material and may be air-cooled or water-cooled as desired. The conveyor is operated by chain or sprocket drive at 43. Material t t'travels into the furnace thru 40 down over the unit hearths 1 and after treatment is discharged thru 42. The rate of travel thru the furnace and hence the duration of treatment is regulated by the rateof revolution of the spiral conveyor 41. By appropriate reducing gearing or regulated chain drive, the rate of dis charge can be made any fixed amount desired from very' rapid to very slow to suit the specific requirements of an individual case.

The combustion gases from the chip bed 23 rising thru zone 24; can be introduced in any quantity desired thru the ports 25 and in any portion desired thru any specific port by positioning the damper slabs .27. The passes into the zone 26 after which it passes over one hearth and beneath the hearth next above it, then thru the ports 10 as indicated by the arrows of Fig. 3.

The combustion gases perform two functions, namely, theyheat the material and interact with the material. Sometimes the heating is the essential accomplishment, and again the treating of the material with hot gases isof greatest importance; or again both heating and treating the material may be accomplished in the processing.

Fig. 4 shows the detail of constructionof one of the ports 25 indicating the wall 13 and the slab 27 in relation to the opening-25.

The slab 27 is shown at an angle allowing I to pass thru 25 at only fractional capacity.

In the above description the hearths have been described as of a metal construction. However, when extremely high temperatures are used under which conditions metals are easily corroded or melted, then I prefer to use a ceramic hearth. Such hearths are cast from the appropriate ceramic mixtures in accordance with good ceramic practice. The method of support and use of the ceramic hearth is identical with that of the metallic hearth previously described.

My invention is especially valuable in heating due to the factthat the hot combustion. gases pass directly over, diffuse into and thru the material being heated. Likewise the radiant heat from the Walls, strikes the upper surface of the layers of material on the hearths and the lower surface of the material is in direct contact with the conductive hearth which is heated by the "circulating combustion gases. Products of reaction and volatile matter are quickly swept out by the combustion gases as the latter pass thru the furnace.

While my invention is described as being of up-draft construction, the same can be easily modified by anyone skilled in the art to have down-draft connections, and further modifications can be easily made to make the furnace both down and tip-draft, depending upon the place of introduction of heat and arrangement of intake and exit fiues from the furnace. These and other changes can be easily made as my invention is adaptable to many variations and to many uses. The above description is given to outline my invention. and not to limit its scope.

I claim:

1. A multiple unit furnace. hearth comprising an incline, integral supporting means for said incline and integral supporting means for another incline used in conjunction with said incline.

2. A multiple unit furnace hearth comprising an incline, integral supporting means for said incline, integral supporting means for another incline used in conjunction with said incline, and gas port-s formed integrally with said incline.

3. A multiple unit furnace hearth comprising an incline, integral supporting means for said incline, means for positioning said incline, means for supporting another incline used in conjunction with said incline and gas ports formed integrally, with said incline, all so formed as to pro duce a unit of manufacture.

4. A cast metal multiple unit furnace hearth comprising an incline, supporting means for said incline, supporting means foranother incline used in conjunction with said incline, and gas ports formed integrally with said incline, all cast as a single integral unit.

5. A ceramic multiple unit hearth, comprising an incline, supporting means for said incline, supporting means for another incline used in conjunction with said incline and gas ports formed integrally with said incline, all formed as a single integral unit.

6. A multiple unit furnace hearth comprising an incline, supporting means for said incline, supporting means for another incline used in conjunction with said incline, said supporting means being so positioned as to allow freedom of movement of the other incline on said. supportingmeans and gas ports formed integrally with said incline, all so formed as to comprise a unit of manufacture.

7. A multiple unit furnace hearth comprising an incline, integral supporting means for said incline, integral supporting means for another incline used in'con'junc'tio'n with said incline, gas ports formed integrally with said incline, all so formed as to comprise a unit of manufacture proportioned in such a manner as to regulate the depth of layers of material to be treated on said hearth.

8. A multiple unit furnace hearth comprising an incline adapted to be supported by the walls of a furnace, cooperating with integral supporting means formed with the hearth unit, said supporting means projecting from the plane of the hearth surface.

9. A multiple unit furnace hearth comprising an incline adapted to be -si'i'pported at. one end by the wall of a furnace and at the. other end by supporting means integrally formed with another similar hearth unit, said supporting means projecting from the plane of the hearth surface.

10. A multiple unit furnace hearth comprising an incline, supporting means for the incline, said incline possessing iirtegral means for partially supporting; another unit incline used in conjunction with said in cline, said partially supporting means proiecting from the plane of the surface of the hearth.

11. A multiple unit furnace hearth comprising an incline supported at one end by the wall of the furnace and supported at the other end by supporting means integrally formed with another similar hearth unit, the unit containing gas ports formed integrally with said incline.

12. A furnace for treating materials com prising a plurality of inclined multiple unit furnace hearths, superposed 'over each other. means for supporting said hearths at one end by the furnace walls and at the other by another hearth containing integral supporting means, said means projecting from the plane of surface of the hearth, means for charging material to be treated and means for discharging the treated material therefrom, "said hearths being positioned at an angle such as toallow the charged material to move through the furnace by force of gravity and means for heating the furnace.

13. A furnace for treating materials. comprising a plurality of inclined multiple unit furnace hearths superimposed over each other, means for supporting said. hearths at one end by the furnace walls, and at the other by another hearth, means for rharging material to be treated and means for discharging the treated material therefrom, said hearths being positioned at an angle such as to allow the charged material to move thru the furnace bvforc of gravity. means for progressively heating the chargei'l material to any desired ten'iperature. means for maintaining said temperature for any desired time in any desired portion of the furnace, and means for cooling the material previous to discharge from the furnace.

14:. A furnace for treating materials, comprising a plurality of inclined multiple unit furnace hearths superimposed over each other, means for suppo'rtingsaid hearths at one end by the furnace walls, and at the other by another hearth. means for chargmaterial to "be treated and means for discharging the treated material. therefrom. said hearths being positioned at an angle such as to allow the charged material to move thru the furnace by force of gravity. a cbmbustion zone "from which any desired amount of hot gases can be admitted to the treating zone to any desired number oi. units, and an exit zone to which any desired amount of gases may be vented from the treating zone from any desired number of units.

15. A furnace for treating materials,con'iprisinga plurality of inclined multiple unit furnace hearths superimposed over each other, means for supporting said hearths at one end by the furnace walls, and at the other by another hearth, said hearths being positioned at an angle such as to allow the charged material to move thru. the furnace by force of gravity, means for "adding hot gases to the furnace, means for conducting the heating gases from incline to incline, means for exit of said'gases, means for discharging the treated material from and means for charging material to the furnace.

16. A. furnace for treating materials comprising a plurality of inclined multiple unit hearths superimposed over each other, means for supporting said hearths at one end by the furnace walls and at the o her end by another hearth, gas ports for conducting hot gases thru the hearths and material passing over the same. said supporting means and gas ports being forn'ied integral with said hearths, said hearths being positioned at an angle such as to au e the charged material to move thru the furnace by force of gravity, means for heating the furnace, means for charging material to be treated, and means for discharging the treated material,

17. A furnace for treating materials comprising a plurality of inclined multiple unit furnace hearths superimposed over each other, means for supportingsaid hearths at one end by the furnace Walls and at the other end by another hearth, said hearths being positioned at an angle such as to cause the charged material to move over the incline and thru the furnace by force of gravity,

OSCAR L. BARNEBEY.

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