US1613054A - Tunnel kiln - Google Patents

Description

T. c. PROUTY ET AL v TUNNEL KILN File ad Nov. 23, 1925 4 Sheets-Sheet 2 Jan. 4, 1927."

LEZGWLZO/ 5; Theodore C. 1 /0749 Jan. 4, 1927.

T. c. PRouTY ET AL TUNNEL KILN i Filed Nov 23, 1925 4 Sheets-Sheet s imeizoraj;

Jan, 4, 1927.

'r. C..PROUTY ET AL TUNNEL KILN Filed Nov. 23 I 925 4 Sheets-Sheet 4 27306732506, Theodore C. 1 /13 y Patented Jan. 4, 1927.

UNITED STA-TE s PATENT OFFICE,

THEODORE PROUTY AND WILLIS O. PROUTY, 0F I-I ERMOSA BEACH, CALIFORNIA, ASSIGNORS, BY MESNE ASSIGNMENTS, TO AMERICAN ENCAUSTIC TILING COM- PANY, LTD., OF LOS ANGELES, CALIFORNIA, A CORPORATION" 'OF NEWi YORK.

TUNNEL 'KILN.

Application filed November 23, 1825; Serial No. 70,775.

kiln which wehave invented and which we describe and claim herein are economy construction and operation and uniformity in the application ofheat to all parts of. the" charge being fired. In tunnel kilns as here-- tofore constructed it has been the practice toload the charge upon cars which are top of the'charge being fired, and thi-slras' pushed through the'kiln, the-kilns formost purposes being of great length ,two to three hundred feet and more and containing acorrespondingly long train of cars loadedwith material being fired. The cars run -u-pon rails laid on the floor of the tunnel. It.is,-of

course, necessary to protect the trucks and they metal structural element frames of the cars from the f excessive: heat- -to which the ware ca'rried by them is 'subfected, and this isv accomplished by provid-" j ing the floors of theflat-topped cars witha layer of material of low'heat conductivity and providing a sand .seal orother formof,

' seal at about the .level of the car-floor be:

. tween the car'and the side walls of the'tun- .nel f, The floor of the car is'the conveyor" platform and the heat must be'applied ex'clusivelyto the spaceabove the conveyor platform in order to avoid injury to, the stru'c-' tural elements and running gearbelowJ In many instances. it is. necessary'that heatbe' applied below as well as atv the sidesand heretofore been accomplished by carrying the ware on a refractory floor,elev ated a ove the car-floor, and'supported- 'on open work through which thelieated air or products of combustion have access" to 1 the space beneath the "ware. In order to affordspace for cars of a capacity that would justify the costofkilns of, thistype used for the manufacture of tile, brick, pottery, sanitary"w-are, ere-,- it hasbeennecessary to makethe lnter or.

s of. the under width of the tunnel "not less than four feet,

to be fired having substantially thesamev cross-sectional area..'\Vhethe1 the ware is inclosed in saggers orset in open formation it has been found impossible to impart a uniform temperature throughout a mass of such large crossrse'ctional area. .-The' inequality in heating'isfrequently so great that the shrinkage of ware at the bottom and sides beforelike shrinkage has taken place in the Ware at the top makes the mass insecure and causes it to topple over; In someinstances the tops of the cars, have been given a pitch of a half-inch'toward the center in an endeavor to counteract the tendency of the waretotopple over from thisuneven shrink= agel Furthermore the refractory to )5 of the cars are constantly expanding an contracting'. as 'the c ar's move through the tun-' .nel andjare taken from the tunnel for unloading and reloading thus necessitating frequent replacement. Theinitial cost of-tun nel kilns: of such large dimensions and the large equipment-of cars constitutes a' heavy item of expense in the manufacture of cefiimic artioles. i

By means of our invention described and claimed herein We; greatly reduce the initial "cost ofthe kiln. without reducing its capacity proportionately and at. the. same time render possible and practicable a much moref'uniform heating" of all parts of the 'chargethan has been. possible or practicable in" kilns 10f thetype above described. Our

improved'kiln possesses the further advantage of dividing-"agivenoutput among several kilns inplace of firing it allin one k ln of the large dimensions heretofore used, thus minimizing the damage consequent upon any irregularity or-accident in they operation of one of the kilns. 7

In our improved kiln the firing chamber through which the ware is moved is provided with'a stationary. fioorto the underside of which the heated gases have access, this floor in the kiln herein described formingpart of a continuous muffle extending from end to end of the kiln and being heated at the sides and top as well as at the bottom. The ware to be fired is set upon rectangular slabs of a suitable refractory material. Each slab with its charge set on it is laced on an exterior extension of the mu e floor. and pressure exerted on it by a plunger moves it into themuftle and imparts movement to all of the slabs already in the mufile, all of them being in contact, edge to edge. The movement of the plunger is timed to give the material the proper time of firing in its passage through the tunnel. Additional slabs with their charges loaded upon them are introduced by withdrawing the plunger sufliciently to make space for placing the additional slab upon the exterior extens on of the muflle floor between the last preceding slab and the plunger. By means of th s con struction, we have eliminated the mltlal cost and the expense of maintenance of the cars heretofore used in tunnel kilns, and have at the same -time. made it poss1ble to economically construct and operate a tunnel kiln of sufliciently small cross-sectional area to secure uniformity in the heating of different parts of the charge. While it might be theoretically possible to construct and oper ate a tunnel kiln of small cross-section with cars of the usual type and might be economically possible to do so 1n the manufacture of articles commanding a sufficiently high price, such a kiln would greatly exceed our improved kiln in cost of constructlon, ma ntenance and operation, and 1n such a kiln the ware could be heated from the under side only by supporting it on open work built up on the car floor, thus reducing the useful capacity of the kiln to that extent, whereas in our improved kiln heat is applied directly beneath the fioor and communicated "therethrough and through the supporting conveyor slab to the ware. In our improved kiln there is a uniform communication of heat to the ware from all four sides of the mufiie;

In the drawings: Figure 1 is a side elevation of our 1mproved kiln.

Figure 2. is a. sectional plan new on the broken line A.-A of Figure 1.

Figure 3 is an end elevation, the left-hand part being broken away on the l1ne B-B of Figure 2.

Figure 4 is a section on the line DD of Figures 1 and 2.

Figure 5 is a fragmentary section on the line C-O of Figure 1.

Figures 6 and 7 show a drive mechanism.

We have shown the kiln in the drawings elevated to a convenient working height upon the foundations 1 and I-beams 2.

The mufiles 3 and 4 extend throughout the length of the kiln and are formed'of slabs 5 of refractory material. Between the two mufilcs, which are parallel, there is a flue space 6 extending longitudinally of the kiln from a point adjacent the charging end E to a connection with flue 6' of reduced cross section (Figure 4) which latter leads to the stack F. The construction surrounding the muttles adjacent the charging end of the kiln is clearly shown in Figure 2, and in the left-sectional part of Figure 3. The lower part of the kiln construction is composed of several layers of brick, six courses being shown in the kiln illustrated. The mufiies are supported upon the upper part of the under-work of brick. Along the inner ad-' jacent sides the muttles are supported upon solid Walls of refractory brick G. At the outer sides the muflies are supported upon 1 an open work structure of refractory brick or blocks 7, there being free spaces between the members 7 to afford free passage for the heated gases; The exterior walls 8 of the kiln and also the end walls are built upon the underwork of brick. Directed into openings in the side walls of the kiln between the charging end and the high heat chamber 20 we have shown eight burners, 12, 12, 13, 13, 14, 14, 15, 15, four upon each side. The design of the kiln and the features constituting our invention may be adapted to the use of gas, oil or solid fuel for heating.

Immediately adjacent each of the burner, openings and upon the side thereof remote from the charging end of the kiln, the lefthand end as viewed in Figures 1 and 2, we

have provided dividing walls 17 which except by means of the central flue 6. As indicated in Figure 3, the gases and products of combustion from the burners pass into and through the openings provided for them and thence beneath the. muflles where they impinge upon the walls G and flow back to the vertical passages 9 and over the tops of the mufiles and through the spaces 11. During this part of their circulation the heated, gases are confined to the spacebetween adjacent cross-walls 17. Upon passing beyond the edge 18 of the part of the partition 17 above the mufile the gases enter the center longitudinal flue 6 which conducts the gases of all the burners toward the stack); D As indicated in Figures 2 and 4, the high heat chamber is wider'than the pre-heating part of the kiln. We have shown two burn-- lit) ers, 21, her, and, as mg gases and burners 21 circulate beneath the mufiies,

thence pass upward at the outer sides and over the top thereof, whence they sweep downward into the space between the mutfles and through the opening 22 in the end wall 40 of the high heat chamber to a duct leading under one of the mufiles to the stack F as indicated in dotted lines in Figure 2. From the charging end E of the kiln to the end wall 23 of the high heat chamber the flue 6 extends from the top of the kiln to the foundation brick upon which the muffles are supported, as shown in Figure 3. The wall 23 extends across the upper part of the flue 6 and down to a horizontal partition 24 WlllChBXtGIldS the length of the high heat chamber 20. The flue 6 communicates with the space beneath the horizontal partition 24 through an opening in wall 23, thus confining. the gases from the pre-heater burners to the space beneath partition 24, designated 6f on Figure 4. The horizontal partir tion 24 terminates at the end wall 40 of the high heat chamber, and the gases flowing through the flue 6' pass through an opening in end wall 40. The gases from the pre-heating burners and the high heat burners thus come together just beyond wall 40, whence they flow through a duct beneath one of the muflies to the stack F as indicated in dotted lines in Figure 2.

We make the part of the muflies extending through the high heat chamber wider than the end parts as indicated at 26, Figures 2' and 4, for the purpose of providing extra space .in the high heat zone with a view to minimizing the danger of. the operation of the kiln being obstructed by the toppling' over of any of the ware in this part of the kiln.

flo r extending through the muflle and restmg on the refractory floor lining between the side flanges 48 thereof. As indicated at 30 in Figures '1 and 2, we provide exterior ex tensions of the tracks formed by the linings 27 in the bottoms of themuflles; These extensions 30 are outside of thezone of heat and may be constructed of "metal; In charging the kiln a plate 28 is laced upon the track 30 at the charging'en of the kiln and then pushed into the muflle, a second plateis then similarly loaded with ware and In the bottom of the muflies we provide a moved to a position with its edge abutting against the edge of the previously charged plate, and this procedure is repeated as rapidly as the predetermined rate of movement of the charge through the mufile makes room for the insertion of a new plate with its load of ware at the charging end. The series of plates in the muflle are moved forward by exerting pressure upon the last plate to be charged, the pressure being transmitted from plate to plate through their abutting edges thus imparting movement to the entire series. Pressure may be applied to the convoyor plates by any suitable mechanism geared to move the ware at the proper rate for the time of firing necessary. We have shown for this purpose plunger-s 29 which may 'be temporarily withdrawn a sufficient distance to permit insertion of an additional plate between the plunger and the last previously charged plate, and then again clutched to the gearing by which it is moved forward at the rate necessary to move the series of plates through the muflie at the proper speed.

.We have found that carborundum is a suitable material for the conveyor plates 28, this material possessing the necessary strength at high temperatures to transmit through the series of plates the pressure by which they are moved, and our investigations also indicate that the friction is less when the movable plates and the stationary track beneath them are not constructed of the same material and for this reason we prefer to construct the lining 27 forming the track of a refractory material other than carborundum. We have obtained the best results by consfructing one of the parts between which the movement takes place of vitrified mate- 4 than that used in our kiln and thereby wholly or partially vitrified. The carborundum plates 28 move over the vitrified floor plates 27 with relatively little friction and wear, and as the floor plates 27 remain at a substantially constant temperature they are not subject to deterioration from contraction and expansion due to temperature changes.

The earborundum plates 28 are not injuriously afiected by the changes oftemperature to I which they are subjected or by the pressure which they undergo when moved through the kiln as above described. In starting the kiln, and sometimes at intervals thereafter, we find it advantageous to provide a .layer of silica sand or quartz powdered to about 16,mesh between the carborundum plates 28 and thelining 27 in order to reduce the friction, but in operation suflicient powdered material for this purpose will generally be formed by the abrasive action between the conveyorplates and the lining.

parting movement to the movable floor wherein the drive shaft 50, by means of screw 51 fixed thereto, rotates screw gear 52 and shaft 53. Conical clutch member 54 is fixed to shaft 53. Pinion 55 is formed with a co-a eting conical clutch member and is loose on shaft 53 when not clutched thereto by the conical clutch. Hand wheel 56 is screw-threaded on shaft 53 and afiords means for engaging and disengaging the clutch at will. Pinion 55 meshes with gear 57 which is fixed to shaft 58. Pinion 59, fixed to shaft 58, meshes with gear 60, fixed to shaft 61, to which pinion 62 is also fixed. Pinion 62 meshes with rack 63 which, with its head 64, formsthe plunger which bears against the last conveyor plate 28 and thus moves the series of plates 28 constituting the movable floor of'the kiln. lVhen a new plate with its charge of ware isto be introduced into the kiln the clutch is released by turning the hand wheel 56 and shaft 61 is manually rotated by means of handle 65 on hand-wheel 66 in the reverce direction, thus through pinion 62, withdrawing the rack and its plunger head 64 to make room for the introduction of an additional conveyor plate 28. Hand-wheel 66 is then rotated by hand in the directionof the power drive to bring plunger 64 against the newly introduced plate 28, then clutch 55-5 4 is engaged by means of hand-wheel 56, thus restoring the power drive to operation.

In Figure 1, we have shown two openings 32, 33, which extend through the outer wall 8 of the kiln and through the wall 5 of the muflie. As'shown in Figure 5, sleeves 35 of refractory material are fitted to the aligned openings in the walls 8 and 5 and extend across the space therebetween. During the operation of the kiln the outer end of the sleeves 35 may be closed by bricks loosely placed therein. In the event that, because of disarrangement of the ware in the muflie or for other reasons, it becomes necessary or desirable togain access to the interior of the muifle, thebricks may be removed from the openings formed by the sleeves 35 and the contents of the mufile may then be manipulated by suitable -implements, the sleeves serving to confine the gaies to the space between the mufiles and exterior Walls and to protect the implements from the direct action of the heat.

What we claim as our invention is:

1. In a tunnel kiln, a stationary floor constructed of vitrified material, means for applying heat beneath said floor and conveyor- Ineans above said floor for moving mate- 11:11 to be fired through the tunnel of said iln.

2. In a-tunnel kiln, a stationary floor constructed of vitrified material, a movable floor above said stationary floor, means forapplying heat beneath said stationary floor, and means for moving said movable floor through said tunnel.

3. In a tunnel kiln, a stationary floor constructed of vitrified material, a movable floor comprising a series of plates above said stationary floor, and means for applying pressure to said plates to move the same through said kiln.

4. In a tunnel kiln, a stationary floor constructed of vitrified material, means for applying heat beneath said floor, a movable floor comprising a Series of plates above said stationary floor, and means for applying pressure to said plates to move the same through said kiln.

5. In a tunnel kiln, a muflie having a stationary floor of vitrified material, a movable floor resting on said stationary floor, and means for moving said movable floor through said mufille.

6. In a tunnel kiln, a plurality of mufiles arranged side by side with spaces intervening between said mufiles and between said mufiles and the top, bottom and side walls of said kiln, and means for applying heat through said/ spaces to -all sides of said mufiies.

7. In a tunnel kiln, a mufile having a stationary floor of vitrified material, a movsaid stationary floor,

able floor resting on said muflie and floor being constructed of re fractory material, said movable floor comprising a series of plates and means for applying pre-fsure to said plates to move the same through said mufile.

8. In a tunnel kiln, a muflie, means for applying heat to both sides and the top and bottom thereof, and means inside of said mufile for moving material to be fired therethrough, the part of said means within said mulfile being constructed of refractory materia 9. In a tunnel kiln, a mufiie,'means for applying heat to both sides and the top and bottom thereof, a refractory movable floor inside of said muflie and means for said floor through said. muflie.

10. In a tunnel kiln, a muffle, means for applying heat to both sides and the top and bottom thereof, a movable refractory floor inside of said mufile comprising a series of plates and means for applying pressure to said plates to move the same through said 11. In a tunnel kiln, movable floor above said stationary floor, said floors being constructed of different refractory materials, means for applying heat beneath said stationary floor, and means for moving said movable floor through said tunnel.

12. In atunnel 'kiln, a stationary floor, a movable floor comprising a series of plates above said stationary floor and means for moving a stationary floor, a

- above said stationary floor, said floors being constructed of different refractory materials, and means for applying pressure to said plates to move the same through said kiln.

14. In a tunnel kiln, a mufiie, a movablefioor inside of said muflie, said floor and the inner bottom surface of said muffle being of different refractory materials, and means for moving said movable floor through said mufiie.

15. In a tunnel kiln, a muffle, a movable floor inside of said muffle, said floor and the inner bottom surface of said muffle being of different refractory materials, said movable floor comprising, a series of plates, and means for applying pressure to said plates to move the same through said muffle.

16. In a tunnel kiln, a muflie, means for applying heat to the sides, top and bottom thereof, a movable floor inside of said muflie, said floor and the inner bottom surface of said muffle being of different refractory materials, and means for moving said" floor through said muffle.

17. In a tunnel kiln, a muffle, means for applying heat to the sides, top andbottom thereof, a movable floor inside ofsaid mufile comprising a series of plates, said floor and the inner bottom surface of said muflle being of different refractory materials, and means for applying pressure to said plates to move the same through said mufli'e.

18. In a tunnel kiln, a stationary floor, a movable oarborundum floor above said stationary floor, means for applying heat beneath said stationary floor, and means for moving said movable floor through said tunnel.

19. In a tunnel kiln, a stationary refractory floor, a movable floor comprising a series of c'arborundum plates above said stationary floor and means for applying pres sure to said plates tomove the same through said kiln. I

20. In a tunnel kiln, a stationary floor of vitrified material, a movable floor comprising, a series of carborundum plates above said stationary-floor and means for apply-.

ing pressure to said plates to move the same through said kiln.

21. In a tunnel kiln, a stationary refractory floor, means for applying heat beneath said floor, a movable floor com rising a.

series of carborundum plates :1 ve .said stationary floor, and means for applying pressure to said plates to move the'same through said kiln. f

22. Ina tunnel kiln, a stationary floor of vitrified material, means. for applying heat.

beneath said; floor, a movable floor comprising a series of carborundum plates above said stationary floor, and means for applying pressure to said plates to move the same through said kiln.

23. In a tunnel kiln, a muflie, a movable carborundum floor inside of said muffle, and

means for moving said movable floor through said mufile.

24. In a tunnel kiln, amuflie having a stationary floor of vitrified material, a mov able carborundum floor inside of said muffle, and means for moving said movable fioor through said mufile.

25. In a tunnel kiln, a muflie, a movable carborundum floor inside of said mufile, said movable floor comprising a series of plates and means for applying pressure to said plates to move the same through said muffle. 26. In a tunnel kiln, a muffle having a stationary floor of vitrified material, a movable carborundum floor inside of said muffle,

. said movable fioor comprising a series of muffle and means for moving said floor ,through said mutlle.

28.- In a tunnel kiln, a muffle having a stationary floor of vitrified material, means for applying heat to the sides and top thereof, a movable carborundum. floor inside of said muflie and means for moving said floor through said mufile.

29. In a tunnel kiln, a muffle, means for applying heat to the sides, top and bottom thereof, a movable carborundum floor inside of said mu'flie comprising a series of plates and means for applying pressure to said plates to move the same through said muflle. v

30. In a tunnel kiln, a muflle having a stationary floor of vitrified material, means for applying'hea-t to the sides, top and bottom thereof, a movable carborun'dum floor inside of said mufile comprising a series of plates and means for applyingpressure to said plates to move the same through said mufile.

31. In a tunnel kiln, a stationary floor constructed of vitrified material, a movable ifloor supported on said stationary floor, a

layer of loose comminuted material between said stationary and movable floors, .and means for moving said movable floor through said-kiln.

32. In a tunnel kiln, a stationary floor constructed of vitrified material, means for applying heat beneath said stationary floor,

' a movable floor supported on said stationary floor, a layer of loose comminuted material between said stationary and movable floors,-

and means for moving said movable floor through said kiln. v

33. In a tunnel kiln, a stationary floor constructed of vitrified material, a movable floor supported on said stationary floor, a layer of loose comminuted material between said stationary and movable floors, and means for moving said movable floor through said kiln.

34. In a tunnel kiln, a stationary floor constructed of vitrified material, means for applying heat beneath said stationary floor,

a movable floor supported on said stationary floor, a layer of loose comminuted material between said stationary and movable floors, and means for moving said movable floor through said kiln.

35. In a tunnel kiln, a stationary floor, a movable carborundum floor. supported on said stationary floor, a layer of loose comminuted material between said stationary and movable floors, and means for moving said movable floor through said kiln.

36. In a tunnel kiln, a stationary floor, means for applying heat beneath said stationary floor, a movable carborundum floor supported on said stationary floor, alaye'r of loose comminuted material between said stationary and movable floors,'and means for moving said movable floor through said kiln.

37. In a tunnel kiln, a stationary floor, :1

and means for moving said platesthrough said kiln.

39. In a tunnel kiln, exterior and interior walls with a heating space therebetween, said exterior and interior walls having opposedopenings therein, a tubular housing of refractory material extending through said openings and across said space, and removable means for closing the opening through said housing.

40. In a furnace of the class described, a mufiie, a movable floor in said mufiie, means for moving said floor through said muflle, independently controllable sources of heat coacting with separate successive sections of the walls of said muflle. I

In witness whereof, we have subscribed our names this 5th day of November, 1925.

THEODORE G. PROUTY. WILLIS O. PROUTY.

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