US1933051A - Means for continuously manufacturing building bricks and the like - Google Patents

Description

F. FANTA Oct. 31, 1933.

MEANS FOR CONTINUOUSLY MANUFACTURING BUILDING BRICKS AND THE LIKE Filed Jan. 6, 1931 3 Sheets-Sheet 1 Ferd/Hand an v a INVENTOR i ATTORNEY Oct. 31, 1933. F. FANTA 1,933,051

MEANS FOR CONTINUOUSLY MANUFACTURING BUILDING BRICKS AND THE LIKE Filed Jan. 6, 1931 3 Sheets-Sheet 2 BY (D I -4- 744'1 ATTORNEY Oct. 31, 1933. F. FANTA 1,933, 5

MEANS FOR CONTINUOUSLY MANUFACTURING BUILDI NG BRICKS AND THE LIKE.

Filed Jan. 6, 1931 3 Shegats-Sheet 5 Q 11/01/1111,, IIIIIJII/Il/I/ //IIIIII// D] INVENTOR U'W fE/d/nand Fama lav/W ATTORNEY.

Patented Oct. 31", 1933 UNITED STATESVPATENT orrlcs MEANS For: CONTINUOUSLY MANUFAC- TURIING BUILDING BRICKS AND THE LIKE Ferdinand Fant'a, London, England Application January's, 1931, Serial No. 506,868, and in Great Britain January 8, 1930 3 Claims.

chani al means which include heating and heat exchanging devices essential to the dryingjor. ale-hydrating of the clay or admixtures of clays of suitable colloidal and fusible compositions,

respectively, and more especially provides means,

by which each and the severalvvell known devices for clay mixing, annealing and crushing, preliminary to the moulding of building bricks, as also such appliances as are now currently in use in the process of moulding drying, preheating, firing and final cooling of the. finished goods, are co-ordinated, with such modifications as may be necessary to constitute a continuous and as far as is practically. possible,.automatic method of covering the whole manufacturing condition when same are ready for stacking or storing. 7

According to-this invention fully fired bricks and auxiliary heat retaining elements are passed 1 through successive independent cooling stages after leaving the furnace and the,raw bricks are passed through said successive independent stages on their Way to the furnace, theraw or 1 partly heated bricks in each stage being preheated or further heated by some or allof the heat extracted from the bricks cooling in that stage, said heat being augmented by auxiliary heating means if necessary, the improvedmeth- 0:. being carried out by apparatus and .machinery comprising a furnace, heating means for said furnace, a power operated conveyorpassing,

through said furnace, a tunnel enclosing. the conveyor on a feeding incline to and on a discharge path from said furnace, heat non conducting means for dividing said tunnel into stages or sections, means for heating either or,

any of the stages and means for supplying all the heating means with combustible "material.- I am aware that thedryingpre-heating, and

can be carried into practical effectin a reliable process of brick making from raw clay ontofthe burning of bricks and their ultimate cooling has been propounded and carried out either] separately or partly in combined manner and that. mechanical means purporting to constitute a continuous heat treatment of bricks and clay goods has formed the subject of prior knowledge. 0 and I do not claim any of the methods so set forth per se nor the conveying or mechanical means so put forward. I

The present invention consists in a method and .means by which bricks andlthe like are 5 treated and-conveyed from start to finish either separately or in sets of bricks andthe like, i. e..

from the moulded to the-burned stage in a continuous cycle and progress of travel through the several stages of drying, pre-heating, burning, and cooling, unintermittently through zones wherein progressive increasingand separately controllable temperatures are maintainableby external means, and so proceed on theirtravel,

in opposite direction to that of the flow of the heat producing gaseous fluids and products of combustion wherebycounter current heat transference is obtained owing to the provision of a system of combined totally enclosed zoneswhere .by complete and gradualheat transference be 0.

tween such gaseousheat producing fluids and the goods to be treated iseffected', and whereby a the heat emitted by the burned and finished bricks, on their return path, is rendered available and fully utilized: for the purpose of drying by 35 radiation the in-coming goods travelling in a plurality of super-posed tiers above and in close proximity of such out going bricks. The, whole method of heat treatment of the goods being carriedout in'a unit of combined totally enclosed zones, as described hereafter. 1 A' further important feature of this invention consistslin the provision of a totally enclosed. space provided for between the outerwalls and the inner walls or lining'of the furnace used 95.

for pre-heating zone, and between corresponding walls of the kiln or firing zone, within which the mechanical conveying means are housed for the purpose of preventing undue heating'of such driving mechanism whilst p'reheating the air 10o eventually to be used to complete the combustion of the gaseous fuel within the kiln section, to admix with and attemperate the gaseous product of combustion in the pre-heating zone and to be utilized 1 for increasing the volume and reduce the temperature of the said products of combustion passingthrough the drying chamber before such combined admixture of spent combusted gases and secondary air is allowed to go to exhaust.

It will be convenient for the purpose of the description of the method if the subject matter of this invention be sub-divided as follows,

namely:-

Cycle of travel" of the goods to be treated between the state where the goods are loaded on the trays or carriers, and the point. where they are to be delivered for stacking purposes.

(b) Construction of the tunnel or drying chamber, of the pre-heating furnace and of the kiln.

(0) Sequence of heating and firing of.the' gaseous fuel and of the combusted gases.'

(d) Means and devices used for the regulation and control of the conveying and of the firing methods and of the adjustment thereof respectively. f

In order further to simplify such description, and to make the references to the accompanying drawings moreclear, the several zones and cycle of operation of the plantas'shownthereon will conveniently be subdivided hereafter as follows, namely:' i

-A"-Drying zone wherein preliminary preheating-of incoming bricks by radiation from the outgoing goods and by heat-transference from the products of combustion takes place. -further pro-heating and d e-hydrating zone by means of the passage therethrough of the combusted gases and by auxiliary heating, if required. Cdirect or final open firing of the bricks or similar goods, and, Dcooling with transfer or exchange of heat from the fired and finished goods to the incoming bricks when the former are returning through the lower duct.

The accompanying drawings illustrate the above method of providing a continuouscycle of operations wherein the trays carrying the goods to be treated subsequently in the saiddiiferent zones (A, B and C) travel in the direction shown on the drawings as indicated by arrows from left to right, whilst the flow of the heat producing gases and of the products of I combustion, impinges on and moves in the opposite direction, namely from right to left of bination of drying, pie-heating, firing andheat exchange plant according to this invention.

Figure 1 and Figure 1 are diagrammatic longitudinal vertical sections of the whole plant illustrating zones A, B, C, and D, including the loading stage, andthe delivery-of the finished goods after their return delivery through zone D from zone C. v

Figure 2 and Figure 2 are a plan diagrammatically illustrating zones A, B, and C including the loading stage and the delivery of the V goods to stack, but not showing zone D for the sake of clearness of the figure.

Figures 3 and 4 are diagrammatic vertical,

cross sections of zone B and zone C respectively,

with extended illustrations of some of the parts not actually within the same plane.

Figure 5 is adiagrammatic representation in front elevation of the extreme left part of zone B, and of the extreme right part of zone C illus I trating the gaseousfuel and combustion sustain ing gaseous fluid distributing mains and also the secondary air conveying main; the external mechanical sprocket-wheel drives not being shown in such view.

Figure 6 represents a diagrammatic view the brick carrying trays.

Figure 7 illustrates diagrammatically one of the known devices for maintaining constant pressures of the gaseous fuel and of atmospheric air, respectively, before admission to the burners. The description and function of this device are set out hereafter:-

"Figure 8 shows the construction of the special duplex quantitative slide valve as used in conjunction with this invention for the purpose of controlling by adjustable means, the quantity of the pre-determined admixture of gaseous fuel and atmospheric air to the series of mixii g valves and burners. The upper view is a plan of the bottom of the valve-box with the valve removed. The middle view is a longitudinal section of the valve-box and valve. The lower View is a plan of the valve apart from its box, the ports in the valve being shown in dotted lines.

Figure 9 is a diagrammatic view of the several prong-chain, sprocket-wheels, showing the manner in which the intermeshing of the prongchains engage the swivel pins of the carrying trays.

Figure 10 represents one of the sprocketwheels, admission plate attachments and provision for accommodation of theguiue rollers of such trays, and of the prongs of the chains, where same have to be supported in inverted position.

Figure 11 is an illustration of the device used for retarding the admission of v the trays to the last mentioned notched tray admitting plate, until such time as the prong chain has reached a point where-the next tray can be taken up by the prong chain. 7

The sequence of operations and direction of travel of the goods ensues in the following manner:

Trays 1, preferably made of refractory materials 'With swinging pin attachments 2, provided at their extreme end with guide rollers 3, are loaded at the loading stage with the bricks or similar materials intended to be treated, and aretaken up by elevator 4, to such a level as will permit their being conveyed by gravitation over pass into zone B of an inclined rail track 10 leading to the first endless horizontal prongchain 11 of zone B; the manner in which such delivery is effected being set out in detail hereafter, in conjunction with Figures 10 and 11.

The manner in which the trays having reached the upper left hand point B of zone B are conveyed within the limits of such zone consists in them beingcarried along from left to right on the first tier 16 of trays, and thence from right to left on the second tier 17 and so alternately, until they reach the last horizontal tier 20 (this being the end of their travel within said zone), by a series of endless prong carrying chains 12, 13, 14 and 15, actuated from without the furnace,

:all the prongs 21 of said chains intermeshing and forming driving elements of such trays, and it follows,;o'wing to the admission-timing and admission-retarding arrangements illustrated in Figures 9,10 and ll, that these'provide for the intermittent advance of series of five horizontally superposed tiers of carrying trays, namely, one such series of closely following trays on each of the five superposed tiers of trays diagrammatically shown inFigures land 2.

Tray guide guards 22, Figure 6 are provided for the purpose of preventing thev rollers 3, attached to'the pins 2 from losing contactwith the prong-chains and sprocket-wheels. These guards, however, are required and provided only at the right-hand ends of prong-chainsll and 13 and at the left-hand ends of prong-chains l2and l4, namely at points where the trays have to pass from the odd toflthe even numbered and from theeven tothe odd numbered prongchains.

Trays 1, Figure 6, having so travelled in zigzag fashion from the first to .the fifth horizontal tier, following the direction of the arrows as shown, reach the extreme point of their travelin zone B at B where they are conveyed on inclined parallel rails 23, similar to those upon which they entered said zone at B, when their admission to zone C at C is controlled by similar means to those shown on Figures 10 and 11.

The trays on so being admitted to zoneC are engaged by endless prong-chains 24 to 28 (both inclusive) in every way identical with prongchains 11 to 15 of zone B, but in this zone, the I prong-chains are actuated and working in vertical direction so that the trays are each, instead of being conveyed in horizontal ,tiers, carried along in six sets of vertical rows constituting six vertical formations moving successively in upward and downward directions.

Similar tray pin and roller retaining guideguards 29, such as have been-referred tounder reference 22, in conjunction with zone B are here provided at the lowest sprocket-wheels turning points where the trays pass from the odd numbered to the even numbered and from the even tending from point C to the delivery point 32 in,

proximity of theloading stage or at such other position as may be chosen for such ultimate 'delivery of the finished products. This duct D is roofed .in up to a point slightly beyond the left hand end of zone B (Figure l) but is open at the top where it emerges below zone Ayfor the purpose of heat exchange by radiation and consequent cooling of the out-going bricks.

Having described the manner of travel of the trays carrying the bricks from the loading stage to the point where they reach the stacking position, it is all important to point out, that it is essential to ensure their being constantly maintained in parallel relative positionnamelyj at right angle to the linear course on their travel by strict synchrcnism of the prong-chains on each side of such trays. For this purpose two endless prong-chains 33 are provided in zone A and are used both for the elevating gear 4 and for the inclined tracks, 5, Sand '7 as well as for the horizontal return from point 8 back to-the lowest point of such elevator 4. Figure 1 In this zone the synchronism is ensured bycross shafts connecting the five parts of sprocketwheels as shown in Figures 1 and 1 and in dotted lines in Figures 2 and 2.

Since it is an important feature of this inve'ntion that the whole of the mechanical means of conveying the trays and their load through the heated furnace B and the kiln C be kept en-' tirely outside the inner refractory lining of such furnace and kiln and housed in'the outer air space E provided for such purpose, the synchronism of the set of horizontal prong-chains 11 to 15 of zone B and of the set of vertical prong-chains 24 to 28 of zone C, is obtained byv external cross shafts synchronizing all the driving gears oi-the sprocket-wheels on either side (frontand back) of each of the two zones, separately, namely, by an independent external cross shaft. driving the several sprocket-wheel shafts where they protrude through the brick or masonry erection enclosing the furnace B and kiln C respectively.

The synchronizing of the endless prong-chains 31' of duct 1.) is obtained in a manner similar to that described above in respect to zone A.

It should also be noted that whilst the said synchronism of the four systems of endless chains 33 in zone A, 11 to 15 in zone B, 24 to 28 in zone C, and of chain 31 in duct D, is thus provided for, it is essential, in order to constitute a continuous regular supply of trays from zone to zone to provide mechanical means for securing the same linear speed of advance merit of all four sets of prong-chains, for which 1 purpose the four sets of external synchronizing V shafts are directly driven by a prime motor shaft by means of gears or by coupling direct to the prime motive power.

It will be clear from what has been already been said herein that the only pointwhereat the trays leave contact with the prong-chains is where they have to pass from one zone to the next contiguous one when they are conveyed on short parallel inclined rail tracks atS, l0 and 23. T1

The manner in which the passage from zone to zone is efiected may best be made cl ar by reference to Figures 10 and 11, the former of which'illustratesthe notched admission plate 34, Figures 10 andll, which is designed to admit six consecutive trays at each complete revolution of the prong-chainsprocket-wheel, the prongs on the chains being disposed on such chains .at equal appropriate intervals, corre ponding with the length of the are extending irom centre to centre lines of such notches, namely 69.

The tray carrying pins 2 and rollers 3 come to rest when they slide on the outer edge of the periphery of the notched plate until the next notch is opposite such pins, when the chain takes up the tray and carries it forward in the horizontal direction in zone B and vertical in zone C, p

. Since it is, however, necessary to allow the tray last admitted and taken up by the prongchain to be sufficiently advanced on its travel to make clearance for the next incoming tray, an admission-retarding device illustrated in Fig ure 11 is provided on each ofthe three parallel inclined rail tracks at 8,10 and 23. This retardcomes into contact with cams 38 fixed on the side of the admission plate 34 on radii at 60 apart, and disposed on the circumference, relatively to the radii passing through the centre of the notches, so as not to release the tray from its temporary stationary position on the rails, until the previously admitted tray is cleared, when the pins of the trays slide to rest on the edge of the notched plate, whilst the retaining lever 36 is again holding up the next tray on the inclined track rails.

Having described the manner in which the goods are conveyed through the three consecutivezones and the mechanical means employed to that end, it is important to refer more particularly to the construction of the different sections of the plant especially with a view to emphasize one of the important features of this invention, which. consists in the method by which all mechanical conveying and forwarding appliances or gears are housed and operated outside the inner space of the furnace B, and of that of kiln C, and are protected against the heat and effect'of the combusted gases existent within such furnace and kiln as set out hereafter, and illustrated in Figures 1, 2, 3 and 4.

As will be seen by referring to these last mentioned diagrammatic representations the furnace B and kiln C each constitutes a totally enclosed chamber, and these are built up entirely of refractory materials.

The inner end walls a and b of furnace B, and inner end walls 0 and d of kiln C have apertures only at B and B in the former, and at C and C in the latter, to allow the passage of the trays and of the combusted gases.

The lateral walls R of furnace B have horizontalslots e, f, g, h and i, to allow the pins 2 of trays 1 to pass along within them with corresponding semi-circular slots at the alternative even and odd numbered turning points of such trays. Intermediate horizontal bafile plates or partitions, To to 0, Figures 1 and 3 extending from one lateral wall to the other, and abutting alternately on the opposite end walls deflect the heating and combusted gases in zig-zag fashion from B to B thus travelling in the opposite direction to that of the brick carrying trays.

vThe lateral walls S of kiln C have vertical slots p, q, r, s, t and 22, Figures 1, 2 and 4, to

allow the pins 2 of trays l to pass within them with corresponding semi-circular slots at the top between the first and second, the third and fourth, and between the fifth and sixth vertical slots and semi-circular slots between the second and third and between the fourth and fifth vertical slots at the lowest part of same. Intermediate vertical refractory perforated bafile plates or perforated refractory firing tubes T shown in Figures 1 and 4 are arranged between the ascending andthe descending sets of trays which similarly direct and deflect the flow of heating and combusted gases from right to left successively,,in upward and downward directions from C to C, asin zone B, in opposite directions to the travel of the trays, owing to these baflie plates abutting alternately, at the bottom and at the top of the inner chamber.

The whole of the said inner combustion chambers of both zone B and zone C are surrounded onall sides and atthe upper roofing of the furnace and of the kiln, by the air space of E, Figures l, 2, 3 and 4, such space being of sufficient width to accommodateall the mechanical driven parts or gears such as sprocket-wheels, notched plate, attachments, prong-chains, etc., it being an important feature of this invention, that all these gears be not onlynot exposed to, but be protected against the heat and contamination of the gaseous fuel and of the products of combustion of same, and be constantly kept at the lowest possible temperature by means of the flow of secondary air surrounding them.

The manner in which this air space, between the actual inner firing chambers and the outer enclosing brick-work or masonry is utilized for such admission of secondary air and for the cooling of the said mechanical parts or gears, functioning thereon, is more fully referred to hereafter.

It should be noted particularly that the narrow open spaces caused by the horizontal slots in the lateral walls of zone B, as also the narrow vertical open spaces similarly caused by the vertical slots in the lateral walls of zone C, are permanently covered by the right and left vertical extensions l and 1 of'the refractory trays 1, as the same succeed each other in the course of their travel, in front ofand in close proximity tothe said lateral walls on each side of the furnace and of the kiln respectively.

As already stated in the specification and in the course of the description of the accompanying drawings, the main object of the present invention is to provide a method by which the incoming bricks are gradually brought into proximity of progressively increasing heating and final firing temperatures and to create si multaneously the gradual exchange of heat between the outgoing bricks and the incoming goods by causing such bricks to travel in the opposite direction to. that which the cycle of combusted gases follow from the point where the highest temperature prevails, within each section and kiln to that where they leave each of the zones wherein heating takes place. An additional important feature characterizing this invention is the method by which the finished bricks are conveyed to meet the incoming bricks, thus completing the counter current effect for heat exchanging purposes throughout the system. I

The specific manner in which, according to this invention, facilities for so gradually increasing the intensity of the heat to be applied to the goods, progressively, as they proceed towards the extreme end of their travel through zone B and kiln C, is provided for, consists firstly':-in the adjustment of the several threeway mixing valves L used at each burner whereby the volume of the gaseous fuel and of the predetermined adequate proportion of atmospheric air or combustion sustaining fluid is allowed to reach the burners nozzle, within the unit of time is regulated, and thus the temperatures can at each burner be controlled to such varying extent as may be required locally, and consists, secondly, in the provision of means by which the bulk or volume of the gaseous fluids can, simultaneously, be regulated at all such pre-adjusted burners by a duplex quantitative slide valve as illustrated in Figure 8, and diagramatically shown in Figure 2 on each side of the furnace and kiln (although in practice one of these slide valves may so control the l supply of both gaseous fluids on both sides of the system).

The construction of the duplex slide valve 'consists of a bottom plate 39 provided with an inlet 40 and outlet attachments 41 for the gase- 150 ous fuel, on one of its sides with rectangular longitudinallyv extended corresponding ports .42 and 43 on its upper surface and atmospheric air in and outlet .attachments 44-and 45 with rectangular longitudinally extended corresponding ports 46 and 4'7, the axial centre line of which is para el to that of ports 42 and 4.3.:

The inlet port 46, through which the air is admitted, carries a cross slide or obturating plate 48, by means of which'the width of such port. may be reduced by a screw attachment, diagrammatically shown at 49, the sectional area of such port being, thus under control,ir-- respectively of the relative on ofv the sliding member 50 of the device.

The member 50 is slidingly-pressed against the bottom plate 39 and against a sliding 'plate' 51, (the simultaneous longitudinal travel of which is secured by vertical retaining pins'53), by

springs 53 which, in turn, press such sliding,

plate against the top-plate 54 of the device. Top-plate 54 and bottom-plate 39 are bolted or otherwise firmly held in position by side-plates, not shown on Figure 8 for thesake of clearness of the diagram. The lon itudinal displacement of the sliding member 50 is obtained by means of a screw and hand-wheel 55 .or by lever or similar attachment.

The function f this sliding member is to establish communication between ports 42 and 43 also between ports 46 and 47 and to allow the admission of more or less of each of the two gaseous fluids in relative proportions determined by the previously adjusted position of the obturating plate 48.

The extent of longitudinal displacement of the sliding member 50 is thus the only determining factor of the sectional area available for admission of both gas and air, and consequently constitutes a positive means of mensuration of both emerging fluids.

As the and gas admitted to the duplex quantitative slide valve are lrept at constant relative pressures by separate pressure regulating devices such as illustrated in Fig. '7 and described hereunder or by any similar device the total output capacity, and therefore the British thermal units available within the unit of time, and throughout the whole system of the several burners used in furnace B and kiln C are under permanent and easily adjustable control.

The pressure-regulating device, only tentatively shown in Figure 7, as not forming any part of this invention, consists of a lower casing divided into two compartments by a central division with an opening of a restricted area, as compared to those of the in and of the outlet mains. Vertical branchwxtensions from each of the two compartments of the said lower chamber comunicate 'ith respective bells fioating in water and kept in appropriate horizontal equilibrium by means of balancing weights which are displaceable longitudinally on the fulcrum lever connecting the 2 bells and pivoted at centre.

The relative position of the bells governing the available inlet area of the air and/or of thegas is thus rendered function of the relative pressure of the said fluid within the inlet and the outlet mains respectively.

The firing of the brick furnace and kiln, substantially as described above and as illustrated in Figures 1, 2, 3, 4 and 5, normally takes place through the burners controlled by the threequantitative way mixing valves L of zone C through nozzles attached to such burners, three of which are on either sideof this zone firing directly into the inner space of the kiln at the bottom of. the zone, at three points W and at the top, of the zone at two points X, the ignited gaseous admixture being in each case admitted between .thevertical perforated baffle'plates or inside the vertical firetubes T used in this zone to prevent the flames oi the gaseous fuel impinging directly on the of bricks on either side thereof. The gaseous fuel being under pressure above atmosphere is deflected zig-cag fashion by these baiile plates so that the combusted gases leave zone C at C" and are in turn deflected zig-zag fashion, horizontally in'zone B emerging from same. at B and thence enter the drying chamber A, finally being taken to exhaust by induced draught or similar device. I

Auxiliary'firing burners with similar three-i way mixing valves and refractory firing nozzle protruding through the inner lateral walls 'of zone B at points shown in' Figures l, 2, -3, 4 and 5 admit ignited gaseousiadrnixture to supplementand/or complete the combustion of the 1 9 products of combustion emerging from zone C if such auxiliary firing is considered necessary.

Both zone C and zone B are provided with apertures M and -N, Figures .4 and 3, at the top or roofing of their inner'lining, respectively, and

with corresponding relief openings 0 (Figure 1) in the outer brick-work, and obturating covers, for lighting up purposes, and for the purposeof allowing the combusted gases to exhaust when one or the other of said zones is to be heated independently of the contiguous one, when communication between such zones is temporarily. out off by the closing down of the fire-proof cur.- tains P, Figure 1, the mechanical drive of the trays is then temporarily brought to standstill,

for such length of time as such intermittent individual firing of such sections is proceeding.

Secondary air at a pressure slightly above that of the admixed gaseous fuel .is conveyed on either sideof the combined furnace and kiln 12) by an air main H with branches K admitting, such secondary air to the air space E provided between the inner refractory lining of zones 13 and C, and the outer brick-work completely surrounding same, at the several points-K (Fig 1 % ures 1, 2, 3, 4 and 5). been utilized in the hollow air space E more especially for the purpose of preventing undue heating of the mechanical parts housed therein and being thus pro-heated, finally finds free ac- 139 cess to the inner space through orifices or elongated openings in the vaulted top or roofing of the inner lining at M and N, Figures 4 and 3, respectively, when such proportion of same as This air, after having is required in the manner of secondary air to 13;!

complete combustion is made available.

The air main H which connects all the secondary air branches K, leading to the hollow air space E, may have an obturating orpartly closingdevice for the regulation of the amount of 140 air so to be allowed to pass into the air space E, according to requirements.

I claim:- 1. Apparatus for the heat treatment of bricks in a furnace having drying pro-heating burning 11R wheels mounted on the furnace structure adapt- 1&0?

ed to support and drive said chains, a series of detachably and swingingly supported trays, swivel attachments on said trays adapted to engage the prongs of the said chains, means adapted to cause the said conveying chains to alternate- -lytravel in clockwise and anti-clockwise direction'when the parts of said chains are contiguous to one another, the said swivel attachments being adapted to engage between the prongs of the taut portion of the said chains and the loose or return portion of the next oppositely facing contiguous chains, said opposite prongs meshing with each other all along said chains, means adapted to transfer the detachable trays at the sprocket wheel end of each alternate horizontal and vertical chains from one chain to the other, guiding means at the sprocket wheel ends of each alternate chain and means for carrying out and regulating the transfer of the trays through apertures in the dividing walls of the furnace from the last set of said conveying chains of one zone to the first set of chains of the next contiguous zone. a

2. In apparatus for the vheat treatment of I bricks as claimed in claim 1, housing means for the plurality of conveying chains, sprocket wheels, guiding devices and transfer devices, wholly disposed outside of the inner heated spaces of the pre-heating and of the burning zones of the furnace; in combination with mechanism, externally located and means for synchronously operating the said sprocket wheels, conveying chains and attachments located in the housing spaces.

3. In apparatus for the heat treatment of bricks as claimed in claim 1, means for the direct unimpeded heat exchange by open ascending radiation between the burnt bricks on their return travel from the extreme or final firing end of the burning zone, within and at the lowest part of the drying zone, and the incoming bricks above; separate individually adjustable burners in the pre-heating and in the burning zones, a main duplex quantitative gas control

Images