US1704796A - Means for the continuous drying or distillation of fine granular masses - Google Patents

Description

March 12; 1929. HON|GMANN 1,704,796'

MEANS FOR THE CONTINUOUS DRYING OR DISTILLATION OF FINE GRANULAR MASSES Filed April 20, 1927 S Sheets-Sheet l 3 Sheets-Sheet 3 L. HONIGMANN MEANS FOR THE CONTINUOUS DRYING'OR DISTILLATION OF FINE GRANULAR MASSES Filed April 20, 1927 Much 12,, 1929.

March 12, 1929. HQNIGMANN 1,704,796

- mums FOR THE CONTINUOUS DRYING 0R DISTILLATION OF FINE GRANULAR MA'SSES Filed April 20, 1927 s Sheets-Sheet 5 mama Ma. 12,1929.

UNITED STATES PATENTOFFICE.

LUDWIG HONIGMIANN, 0F BICHLERHOF, GERMANY.

MEANS FOR THE CONTINUOUS DRYING 0R DIS'IILLA'IION OFFINE GRANULAR MASSES.

Application filed This invention relates to means for the continuous dry-ing or distillation of fine granular masses and has particular reference to apparatus comprising a container through which the heating agent and the material under treatment are both caused to flow. In

apparatus of this kind, it has hitherto been customary to employ a drum-shaped container which was rotated about its longitudinal axis in order to effect rapid and thorough heat transmission by insuring intimate contact between the material under treatment and the heating gases. This arrangement has the disadvantage that the heavycontainer has to be mounted rotatably and it is further inconvenient inasmuch as the inlet and out let connections to the moving drum for the heating agent and the material under treatment are difficult to make and are only rendered possible by adopting special means. A further drawback resides in the fact that particles of dust, which are contained in large quantities in the fine granular material, are

roused up ineddies by the agitation of the mass and entrained by the exhaust gases, from which they have to be separated out again in apparatus provided specially for this purpose.

The apparatus of the present invention has for its object to avoid these disadvantages. To this end, according to the invention, the container is provided with bodies adapted to be easily heated and such bodies are caused, either by. rotatin or by oscillating them, firstly to travel through a chamber of the container which is traversed by hot gas, wherefrom they take up heat, and, secondly to dip into the mass of material to be treated, wherein theygive up their heat again. I

In one preferred constructional form of apparatus according to this invention, there may be employed a series of perforated d scs arranged in a row upon a common driving shaft, or the like, and in bafile fashion in the container (of which the upper part is traversed by heating gases and the lower part by the material under treatment) that the gases and the material both are c0nstrained to flow through the perforations in said discs. If now these sheet metal discs be either continuously. rotated or oscillated to and fro, they take up heat during their passage through the space which is filled with hot gases and give up this heat to the charge of material by dipping into the latter where it is filled up in the lower part of the conin sucha way April 20, 1927, Serial No. 185,323, and in Germany November 5, 1925.

tainer. By reason of the continually repeated movement of the heating surfaces between the heating chamber and the chamber contaming the material to be heated, overheating of the thin metallic sheets is avoided, since these are constantly giving up to the charge the heat which they acquire. Feed of material through the container takes place in a very simple manner. The material first of all tends to pile up at'the inlet end of the container but, being kept in motion by the dipping metal discs, it flows towards the outlet end byreason of its own weight, It will be observed that thev perforated sheet metal discs do not themselves exert a feeding action but the fact of keeping the material in motion suflices to enable the same to flow, of its own accord, downhill, as it were, through the holes in the metal discs, to the outlet end of the-container. This action can be accelcrated by adapting the known expedient of mounting the drum so that it inclines from the inlet towards the outlet end. The discs are kept as smooth as possible, so .as to prevent eddies of dust from being set up and, as a further precaution in this direction, the perforations may be given a conical form which minimizes the adhesion of dust as the plate emerges from the granular material.

If desired, the perforations may be so formed as to facilitate feed of the material from the inlet to the outlet end of the container. According to requirements, the flow of gas and the flow of charging material may take place in the same direction or in opposite directions. The heating gases may be conducted in a circuit through the drum and through a reheating apparatus.

In many cases the gases are vapors and gases arising fromthe material in the heat treatment of granular masses contain valuable constituents, which it may be very profitable to recover.

In the coking and distillation of bituminous masses, such, for instance, as brown coal or the like, the oily vapors form a product which in value may far exceed that of the coke or semi-coke which is obtained.

In this case it is advantageous to prevent the gaseous or vaporous products of the theatment, which emanate from the material under the influence of the applied heat, from being carried off in the hot gases. To this end means are preferably provided for preventing these gaseous or vaporous products arising from the charge from mixing with the gaseous heating medium and for causing them to be conducted away separately or recovered. For this purpose a modified form of apparatus accordlng to the invention is employed, the characteristic feature being that, in addition to the heat exchange bodies which either by rotary or by alternating oscillatory motion, traverse the heating space and dip into the mass of the charge, other and fixed heating bodies are provided in the heating space and are located between the movable heat exchange bodies. By means of these heating bodies the necessary radiant heat is transmitted to the heat exchange bodies whereby it is conveyed and transferred to the material of the charge. vThat part of the container which, in the form of construction herein first described, was traversed by heating gases can now be utilized for the accumulation of gaseous distillation products which can thence be conducted away freely and uncontaminated and utilized if required.

Although, as above mentioned, an important advantage of the new apparatus resides in the fact that rotation of the container wall itself is avoided, the rotating heat exchange bodies according to the invention may also be used in conjunction with rotating drum shells. I o This form of construction may be employed in special cases and is generally useul in the drying treatment of such substances as show little tendency to form dust or stick to the wall of the drum. If the drum be rotated only slowly it is possible to avoid mutual eddying to any harmful extent between the material to be dried and the heating medium. Such an arrangement may, generally be employed with economy and advantage when it is desired to obtain the advantages alforded by heat exchange bodies according to the invention while utilizing existing rotary drums and thereby saving the much greater cost of an entirely new container installation.

In this form of construction the heat exchange bodies of an apparatus according to rotatably mounted drum s ell.

The difliculties attendant upon the separate introduction of the heating medium and the charge may be avoided, according to the invention by uniting the heat exchange bodies, the drum shell and a centrally disposed displacement body (which fills up space in the middle of the drum) into one rigid rotary element which rotates on its axis between fixed end walls.

The accompanying drawings illustrate diagrammatically three examples of constructions according to-the invention.

In these drawings Fig. 1 shows one form of construction in longltudinal section,

Fig. 2 is a similar view of a second form of construction.

Fig. 3 is a cross section on the line AA metal discs 0 are fastened in a row on a shaft 6 arranged axially in a drum a, these discs having a diameter substantially equal'to the internal diameter of the drum. At one end, nearly at mid-height of the vessel is an inlet passage d for the material to be dried while at the opposite end, and at the bottom of the drum is located the outlet passage 6.

Above the level of the shaft and at opposite ends of the drum are arranged, respectively,

the inlet and outlet openings f and g for the heating gas. L

The operation of the device is as follows Heatin gas is conducted into the drum through t e inlet passage 7 and serves to heat the perforated metal discs. -The charging material is fed in through the pipe 11. vThe shaft carrying the perforated discs is now continuously rocked back and forth by at least half a turn in each direction. In this way the metal discs convey to the charge the heat which they have picked up from the hot gases in the upper part of the drum. Repeated change of the direction ofrotation has the advantage of ensuring uniform heating of the charge. V

The feed or progression of t e charge through the container from the in ct to the outlet end thereof takes place under the action of gravity, the material fed in tending first of all to fill' up at the inlet end. This tendency of the material to feed by its own weight may be enhanced by arranging the drum on the slant from the inlet to t e outlet end. The sheet metal discs dipping into the charge do not in this case perform the function of a feed screw; on the contrary it is quite suflicient for them slightly to agitate the granules of the charge. Under the influence of gravity theslight movement thus produced extend from the inlet end, through the perforations in the discs, rightaway to the outlet end of the container. In this way a very gentle and uniform continuous feed of the chargin material is secured, the eddying up of dust eing thus entirely avoided.

In the form of construction illustrated in Figs. 2 and 3, as in the example already described in connection with Fig. 1, a preferably cylindrical container a is provided, the bottom thereof being appropriately inclined from the inletto the outlet end. A shaft 1) extends longitudinally through the container and, as before, carries a number of circular to be rotatable about its axis.

parallel walls is extending nearly to the middle of the container. Thesewalls are united, in pairs, alternately at their outer and their inner edges, by transverse wall sections Z, Z, so that the upper part of each disc is enclosed in a sort of pocket open at the bottom, the free spaces between the pockets being open at the top. The structure thus formed, resembling, as it does, half of a ribbed tube, is surrounded by the drum shell or casing m,

\ into which is introduced, through a pipe f, a

mainly gaseous heating medium which, after flowing through the heating jacket, escapes therefrom at g. The inner chamber of the container is connected to outlets 'n, n for the gases and vapors given off by the chargeunder treatment.

The manner in which this device operates is similar to that described in connection with Fig. 1, with the exception that the discs 0 do not come into direct contact with heating gases in the upper part of the container but, instead, are heated by radiant heat from the fixed heating bodies interspersed between them.

The perforations in the plates 0 may be conically shaped (Fig. 5) so that dust-like constituents of the charge may not remain sticking in them and thereby get entrained by the current of gas. Furthermorethe form given to these holes may be such as to facilitate the feeding movement of the charge. The shaft may conveniently be made hollow and, if necessary, Water may be circulated through. it.

In the form of construction according to Fig. 4 the drum a, is, as is usual with rotary drum, mounted on bearing rollers s, s so as driven, in the usual manner, through the medium of a toothed ring 25. The cylindrical drum shell is not rigidly attached to the end walls 1), p these latter being, however, fitted to the shell with the interposition of suitable packing. Suitable means are provided for preventing these end walls from participating in the rotary movement of the drum shell. Thus they can, as in the arrangements illustrated in Figs. 1 to 3, be fitted in the upper half, with an inlet 7 and an outlet 9 for the heating medium and in the lower half, with suitably spaced apart and preferably It may be a an inlet (1 and an outlet 6 for the material to be treated.

The heat exchange bodies, in the form of perforated circular plates 0 are fixed to the drum'shell a the cross-section of which they occupy completely, excepting that middle of the container is occupied by a displacement body 1- to which the discs 0 are also firml attached, and which is made of a size suf ficient to reduce material that dead space about the axis of the drum which cannot be utilized for heat exchange purposes.

Claims. 1. An apparatus of the class described comprising a drum mounted with its axis substantially horizontal, means adapted to supply material in particles at one end of the drum and to permit the removal of said material at the other end of the drum, so that the bottom of said drum may contain a layer of said ma-- terial, conduits adapted to lead a current of heating gas to said drum at one end thereof and to remove gas therefrom at the other end thereof, a shaft mounted axially in said drum, a plurality of solid heat exchange bodies of sheet metal fixed on said shaft within said drum and extending substantially radially from said shaft and having perforations therein serving to permit the passage of the current of gas from end to end of the drum, the area of each of said bodies being substantially equal to twice the cross sectional area of the drum to form baflies therein, said shaft and bodies being movable about the shaft axis so that portions of each body may alternately be brought above the layer of material in the bottom of the drum so that they may be heated by said gas current and thereafter be moved into contact with the material to give off absorbed heat thereto, and means to move said shaft and bodies.

2. Apparatus as in claim 1, in which the said heat exchange bodies are of smooth sheet metal and the perforations therein serving to permit the passage of the current of gas from end to end of said drum have conical mouths so that the bodies may move through the material without carr ing portions thereof along into the current 0 gas.

3. Apparatus as in claim 1,, in which the drum and bodies are circular, and the bodies are movable through at least a half rotation so that each part of the bodies may be in succession and alternately heated and empolyed for heating.

4. An apparatus of the class described comprising a drum mounted with its axis substantially horizontal, a horizontal partition above said axis and dividing said drum into upper and lower chambers, downwardly open pockets on said partition and extending upwardly therefrom, means adapted to supply material in particles into the lower chamber at one end of the drum, and to permit the removal of said material at the other end of the drum so that the bottom of said drum may contain a layer of said material, conduits adapted to lead a current of heating gas to the upper chamber 6 of said drum at one end thereof and to remove gas therefrom at the other end thereof, a shaft mouted axially in said drum below said partition, a plurality of solid heat exchange bodies fixed on said shaft within the lower compart- 10 ment and extending upward into said pockets respectively so that the bodies may be heated from the Walls of said pockets, said shaft and bodies being movable about the shaft axis so that portions of each body may alternately be brought above a layer of material in the bottom of the drum so that they will be beated by heat from said gas current as radiated by the Walls of said pockets and thereafter be moved into contact with the material to give off absorbed heat thereto, and means adapted to move said shaft and bodies.

In testimony whereof I have signed my name to this specification.

LUDWIG HONIGMANN.

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