US1499850A - Retort and furnace - Google Patents

Description

July 1 1924. 1,499,850

L, H. BONNARD RETORT AND FURNACE Filed Dec. 1, 1922 2- Sheets-Sheet 1 HII 15' I v (\HQI MM 1W 77 k 9 50 v B] W WM. 97 m; W

July 1 1924. I 1,499,850

L. H. BONNA'RD HETORT AND FURNACE Filed Dec. 1, 1922 2 Sheets-Sheet. 3

INVENTOI.

Patented July l, 1924.

LEONARD HUGH BONNARD, OF LONDON, ENGLAND.

v nn'rozar Ann FURNACE. Y I

Application filed December 1, 192a Serial in. 604, 33.

To all whom g't may concern:

Be it known that I, LEONARD NARI), a subject of the King of England, re siding at London, in England, have invented certain new and useful Improvements inRetorts and Furnaces, of which the following is a specification.

This invention consists of improvements in or relating to retorts and furnaces.

Tlle primary object is to provide a mufiie furnace or retort in which carbonaceous ma include vegetable materials, crushed ores, V

and so forth, and are hereinafter referred to as mobile material. Under the term furnace as used in the following specification and claims there are to be understood to be included retorts, and generally any form of the apparatus, whether it be'heated externally or by the passage of hot gases through the interior or otherwise.

Various types of furnaces are known in which there is a vertical series of horizontal trays to support the mobile material, and in which rakes or blades (which may radiate from a central rotatable shaft) serve to keep the mobile material turned over or agitated and also serve to transfer the material from tray to tray. One well-known example of such apparatus is the Wedge niechanical furnace. I make no claim to these known arrangements.

Where the mobile material is to be subjected to heat treatment on a series of trays, it is desirable in the first place that the mobile material fed to the apparatus should be distributed in substantially uniform layers (which may be thin layers) on the surfaces of the trays. It is also desirable that the material be turned over from time to .time to expose fresh portionsto the surfaces of the trays, and that the material should be bodily moved over the surfaces of The object of this invention'is to.

cal retort or furnace there is provided the HUGH Boncombination of a series of superposed. horizontaltrays having transfer openings for passages ofmobile material from tray to tray, blades overlying the trays, means for moving the blades over thejsurfaces of the. trays and means for raising and lowering the blades inrelation to thetraysso that they act alternately to spread the material over thetray surfaces and to transfer it toward and through the transfer openings:

- More specifically this invention comprises n a mechanical furnace thecom'bination of a series of superposed horizontal trays having transfer-openings for passage of mobile material from tray totray, a vertical rota table shaft extending through the trays,

blades carried upon the shaft so as to overlie the trays and means for. raising and lowering the shaft with its vblades in relation to the trays so that the blades alternately spread the material overlthe tray surfaces and transfer it toward and through the transfer openings.

In the accompanying drawings whichillustrate diagrammatically I one form I of muf fie retort embodying thisinvention and spe cially suitable for the carbonization of sawdust and for the heat treatment of deco-lourizingjcarbons- I T v V j Figure 1 isa central vertical section showing the general arrangement of the appara f' Q Figure 2 is a vertical section partly in ele- ,vation illustrating the retort proper; 7

Figures 3, 4, 5, and 6 are diagrams illustrating the positions ofthe discharge holes in the hopper, the'top feed plate, the uppermost tray, and the second tray, respectively;

Figure 7 is a horizontal section on] the line 7 of Figure 2.

Referring first to thevertical cylindrical retortf2 by an annular space 3 into which,projectftangen f tiallya "serieseofgas or liquid-fuel burners 41;. disposed near the bottom' of the appara tus. The retort E2 discharges through an outlet 5 into a conveyor chamber 6 provided with a gas outlet 7 "from which the products Figure-1, anjouter an- I nular brickwork setting 1 s separated from otdistillation are led to alcondenser and to a conduit for the residualgaswhich may be for a portion of its-length by a water. tank 9. The treated and cooled material is discharged from the chamber 6 through a vertical outlet 10 and an expansion pipe 11 into a receiver 12 which is normally kept sealed against the access of air and can be readily replaced when filled.

The retort roper comprises an outer cylindrical casing 18 around which the heating medium or flame passes. WVithin this casing is a vertical series of fixed horizontal trays 14 which derive their heat from the casing and transfer the heat to the sawdust which is distributed over the surfaces of the trays. Transfer openings in the form of slots 15 are provided in the trays for the transfer of the sawdust gradually through the apparatus. The slots may be sectorshaped and the slot in each tray may be so arranged in relation to the slot in the tray next above it that the sawdust has to travel almost completely round the tray before its discharge therefrom. A central vertical rotatable shaft 16 passes through the axes of the trays 14 and carries radial blades 17 as shown in Figure 7 there may be five radial blades for each tray. The shaft 16 is free to move slightly in a vertical direction, and may be supported on a transverse bar 18 carrying at its ends two rollers 19 engaging an upwardly-facing co-axial fixed cam surface 20 which determines the periodic vertical movement of the shaft. It will be obvious that various alternative methods may be employed for imparting the vertical movement to the shaft. In the form shown a spur wheel 21 with long teeth is secured to the shaft and engages with a corresponding spur wheel 22 secured to a countershaft 23, having a driving pulley 24. To prevent undue load on the cam, the shaft and the attached members may be counterbalanced to a considerable extent, say by a pivoted lever 25 and an adjustable weight 26. The object of the vertical movement of the shaft is to enable the radial blades 17 to be moved when required into contact with th surfaces of the trays, and to be raised when required to a certain small distance from the trays, so as to spread the sawdust in thin layers over the surfaces of the trays. For example, in the case where the cam or the like allows the blades to be in contact with the trays during a rotation of about I 36, and then raises the blades during a rotation of about 144, the operation is as follows From a suitable feed hopper 27, having an out-let 28 through the cover of the retort, the sawdust falls on to a feed plate 29, having a slot 30 therein. A radial feed-arm 31 secured to the shaft 16 sweeps a certain regulated quantity of sawdust away from under the hopper outlet 28 through the slot 30 on to the topmost of the trays 14.

Figures 3, 4, 5 and 6 indicate the relative intes ate positions of the slots 28, 30 and 15, the radial arms or blades being assumed to rotate clockwise when looking down upon them, so that as soon as the sawdust is swept away from the hopper hole 28 it passes almost at once through the slot 30 in the feed plate, but on each of the trays 14 the saw dust has to be assed almost completely round the tray before it is discharged therefrom. During a rotation of the shaftthrough 144 the heap on the topmost tray is spread out on the surface of the tray. The blades 17 are then lowered into contact with the tray, and these blades, in moving through an angle of 36 in contact with the tray, effect a certain forward movement of the sawdust over the surface, and also turn over the material to a certain extent. The blades 17 are then again raised and effect the spreading during a. further 144 rota tion. By this alternate spreading and shifting the material is gradually transferred through the furnace and it will be noted that in using live radial blades which are in contact with the tray twice for 36 in each revolution, the whole surface of each tray is swept over by the blades at each revolution.

Roughly speaking, the finer the material treated the thinner should be the layers when spread out. Working with sawdust of 32 mesh to the linear inch, quarter-inch layers can conveniently be used.

Apparatus for feeding the mobile material to the retort or furnace may take various forms, it being only necessary that a periodic discharge of the mobile material on to the topmost tray should take place at a suitable place and at appropriate times.

The blades may take a variety of forms, and may, if desired, be specially cooled, e. g. water-cooled.

The method of heating the mobile mate rial may be modified in various ways, for example, in the case of the roasting of ores, the hot gases may actually pass up through the retort itself and be brought in contact with the mobile material.

It is desirable, on the one hand, not to leave portions of the tray surfaces bare or unoccupied for any considerable period, and, on the other hand, not to leave por tions of the tray surfaces which are never swept over by the blades whilst in contact therewith.

The number of radial blades employed and the timing of their vertical movements can be readily selected to effect both these objects.

To this end it is useful to point out that where the blades are lowered into contact with the tray at uniform intervals more than once in a revolution, the period of contact necessary depends both on the number of blades and on the number of times of contact, and is inversely as the least common multiple of thesetwo factors. Thus for a given period of contact the maximum sweeping of the surface with the minimum number of blades is obtained if the number of the blades and the number of times of contact are incommensurable (prime to For example, where the What I claim as my invention and-desire to secure by Letters Patent is:

1. V In a mechanlcal furnace the combination of a series of superposed horizontal trays having transfer openings for passage of mobile material from tray to tray, blades overlying the trays, means for moving the blades over the surfaces of the trays to feed forward the material and means for raising and lowering the blades in relation to the trays so that they act alternately while moving in the direction to feed forward the material to spread the latter over the tray surfaces and to transfer it toward and through the transfer openings.

2. In a mechanical furnace the comb-ination of a series of superposed horizontal trays having transfer openings for passage of mobile material from tray to tray, a vertical rotatable shaft extending through the trays, blades carried upon the shaft so as to overlie the trays and means for raising and lowering the shaft with its blades in relation to the trays so that the blades while moving in the direction to feed forward the material alternately spread the latter over the tray surfaces and transfer it toward and through the transfer openings.

3. In a mechanical furnace the combina tion of a series of superposed horizontal trays having transfer openings for passage of mobile material from tray to tray, a vertical rotatable shaft extending through the trays, blades carried upon the shaft so 'as to overlie the trays and a cam and roller device mounted as to one element upon the shaft and as to the other element on a fixed part of the furnace so as, during rotation of the shaft in the direction to feed forward the material, alternately to raise the shaft with the blades in relation to the trays to spread the material and to lower it so that the blades contact with the tray surfaces and transfer the material toward and through the transfer openings.

4. In a mechanical furnace the combination of a series of superposed horizontal trays having transfer openings for passage of mobile material from tray to tray, a vertical rotatable shaft extending through the trays, blades carried upon the shaft so as to overlie the trays, a roller mounted upon the shaft, and a fixed cam co-axial with the shaft below the roller so as, during rotation of the shaft in the direction to feed forward the material, alternately to raise the shaft with the blades, in relation to the trays to spread the material and to lower it so that the blades contact with the tray surfaces and transfer the material toward and through the transfer openings' 5. In a mechanical furnace the combination of a series of superposed horizontal trayshaving transfer openings for passage of mobile material from tray to tray, a vertical rotatable shaft extending through the trays, blades carried upon the shaft so as to overlie the trays, two rollers carried upon the shaft on opposed sides thereof and a fixed cam co-axial with the shaft below the rollers soas, during rotation of the shaft in the direction to feed forward the material, alternately to raise the shaft with the blades in relation to the trays to spread the material and to lower it so that the blades contact with the tray surfaces and transfer the material toward and through the transfer openings.

3 6. In a mechanical furnace the comblnation of a series of superposed horizontal of mobile material from trayto tray, a vertical rotatable shaft extending through the trays, means for raising and lowering the shaft in relation to the trays more than once in each revolution and blades carried upon the shaft so as to be lowered into contact with the trays when the shaft is lowered, the number of blades for each tray being incommensurable with the number of times of contact of the blades with the trays per revolution.

7. In a mechanical furnace the combination of a furnace casing having a delivery opening to the interior at the top, a feed plate within the casing below the delivery opening, a series of superposedv horizontal trays within the casing below the feed plate having transfer openings for passage of material from tray totray, a central vertical rotatable shaft extending through the trays to the outside of the casing, blades carried upon the shaft so as to overlie the trays, a feed arm rotated with the shaft so as to pass between the delivery opening and the feed plate and to sweep a portion of material from below the delivery opening and off the feed plate on to the first tray, and means for raising and lowering the shaft with its blades in relation to the trays opening, a series of superposed horizontal.

&

shaft outside the casing and a fixed cam coaxial with the shaft below the rollers so as, during rotation of the shaft in the direction to feed forward the material, alternately to raise the shaft with the blades in relation to the trays to spread the material and to lower it so that the blades contact with the tray surfaces and transfer the ma terial toward and through the transfer openings.

In testimony whereof I affix my signature.

LEONARD HUGH BONNARD.

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