Improvements in Dryers.
Year: 1898

page_text: Date of Application, 12th Apr., 1898-Accepted, 4th June, 1898
Improvements in Dryers.
I, BENJAMIN JOSEPH BARNARD MILLS, of 23, Southampton Buildings, in the
County of London, Patent Agent, do hereby declare the nature of this invention,
(a communication to me from Thomas Alva Edison, of Llewellyn Park, in the
County of Essex, and State of New Jersey, in the United States of America,
Inventor,) and in what manner the same is to be performed, to be particularly
described and ascertained in and by the following statement:-
-
The invention relates to an improved dryer adapted for use in drying pulverized
material such as iron ore. The object is to provide a dryer capable of effectively
and economically drying large quantities of material.
In the drawings Fig. 1 is a side view.
Fig. 2, an enlarged vertical section.
Fig. 3 a similar view of the distributer.
Fig. 4, an elevation thereof.
Fig. 5 an enlarged view of one section of the dryer, showing the shaking
mechanism, and
Fig. 6 a section on the line 6-6 of Fig. 5.
Corresponding parts are represented by the same numerals of reference in all
the views.
1 is the drying chamber, composed of sections 2 arranged vertically one above
the other and bolted together. 3 is a foundation for supporting the drying
chamber. The bottom of the drying chamber is formed into a hopper 4, beneath
which is a conveyor 5 to carry off the dried material. 6 is the furnace, having
three fire boxes 7, all connected to a single stack 8. A fan 9 may be used for
supplying forced draft. Openings 10 are formed in the front walls of the furnace
above each fire-box for supplying air to be heated by the same before passing
through the stack 8. 11 is a cover for stack 8 operated by a lever 12. Flues 13,13
connect stack 8 with the drying chamber. A suction fan 14 connected with the
drying chamber at its upper end produces a powerful upward draft therein. The
sections 2, 2, of the drying chamber (with the exception of those connected to
flues 13 and the top sections enclosing the distributer) are all provided with
inclined plates 15 therein, arranged in horizontal rows, a sufficient space being pro-
vided beneath the bottom edges of the plates of each row to allow for the passage of
material. Said plates are carried in slots 16 in the sections 2, see Fig. 5, and hence
are removable. To prevent clogging of material on the upper plates, a device is
provided for agitating the same, which preferably comprises two rock-shafts 17
mounted in bearings 18, each rock shaft being provided in line with each deflect-
ing plate 15 with a bifurcated lug 19, in which is pivoted a lug 20 formed on the
deflecting plate. The rock-shaft 17 may be oscillated by handles 21 to shake the
desired plates and thereby prevent the material from lodging thereon. In order
to properly distribute the material upon the several deflecting plates, a novel
distributer is employed. This comprises an uppermost section 22, two sections 23
beneath the same, four sections 24 beneath sections 23, eight sections 25 beneath
sections 24, and sixteen sections 26 beneath sections 25. The sections 22, 23, 24

page_text: and 25 are each formed of inclined deflecting plates 27, 27, alternately arranged in
the form of an approximate X. The sections 26 consist preferably of single deflect-
ing plates 28 with spaces between them. The several sections of the distributer
are carried by braces 29 in the top of the drying chamber. To distribute the
material lengthwise of the top section 22, a hopper 30 is used having a contracted
portion 31 and a flared lower portion provided with radial partitions 32. With
some materials, such as iron ore, the best results are obtained with relatively small
particles, and I therefore prefer to employ a screen which will reject those particles
which cannot be effectively dried. Three inclined screens 33 are shown arranged
one above the other. Above the top screen is a plate 34, beneath which is a ledge
or shelf 36, similar ledges 37 being mounted beneath the top and intermediate
screens for receiving the discharge therefrom. The purpose of these ledges is to
check the velocity of the material and to thereby effect perfection in screening.
The tailings are directed out of the apparatus through a chute 38, and the screen-
ings will be caught by a chute 39 and directed into the hopper 30.
The operation is as follows. Fire being started in the furnace 6 and the forced
draft applied, the products of combustion will pass through the stack 8 and out at
its upper end, the cover 11 being elevated. When the stack is hot and the draft
well started, the suction fan 14 is operated and the cover 11 closed, so that the
draft will be directed through the branch flues 18. Air will also be drawn by
suction through the openings 10 and will be heated by the fire boxes. The passage
of hot air and products of combustion through the drying chamber will heat the
deflecting plates 15 therein. Material is now fed out of the trough or chute 35,
impinges against the plate 34 and falls onto the ledge or shelf 36, where it accu-
mulates in a pile. As fresh material is added to this pile, it falls from a state of
rest onto the uppermost screen, and so on through the screening apparatus, being
checked before passing over each screen. The tailings pass out of the chute 38
and may be reground, and the screenings dropping on the trough 39 enter the
hopper 30, and in passing through the contracted portion 31 will be reduced to
relatively small area. After passing said contracted portion, the material will be
spread out by the partitions 32 and be deflected into the section 22 of the.distributer,
by means of which the material will be divided into two parts, one half moving to
the right and the other to the left. Each half of the original bulk thus separated
will pass to the sections 23, where a further subdivision takes place, and so on
through the apparatus, until by the sections 26 the material will be divided into
thirty-two thin, even streams, each of substantially the same volume. These
streams of material reaching the deflecting plates 15 will be caused to travel in
zig zag paths downward through the apparatus, and in this movement the material
will not only be subjected to the heat of the plates themselves, but will also
encounter the ascending currents of hot air and the products of combustion, so
that all moisture will be removed from the same and the material will pass out of
the hopper 4 on to conveyor 5 in a thoroughly dried condition.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed I declare that what I.
claim is:-
1. The employment in a dryer of a series of deflecting plates so arranged that the
material in the form of thin layers, will be caused, in passing downward through
the apparatus, to partake of zig zag paths and to meet, in the travel of said material,
currents of hot air or combustion gases or both, by means of which moisture will
be expelled from the material, substantially as set forth.
2. The employment in a dryer of a series of deflecting plates so arranged that
the material in the form of thin layers will be caused in passing downward through
the apparatus to partake of zig zag paths and to meet in the travel of said material
currents of hot air or combustion gases or both by means of which moisture will
be expelled from the material, and a distributer at the top of said dryer for sub-
dividing the material into thin, even streams, substantially as set forth.

page_text: 3. The employment in a dryer of a series of deflecting plates so arranged that
the material in the form of thin layers will be caused, in passing downward through
the apparatus, to partake of zig zag paths and to meet, in the travel of said material,
currents of hot air or combustion gases or both, by means of which moisture will be
expelled from the material, and a distributer at the top of said dryer for sub-
dividing the material into thin, even streams, one or more of the sets of deflecting
plates being arranged to be shaken so as to prevent the accumulation of material
thereon, substantially as set forth.
4. The employment in a dryer of a series of deflecting plates so arranged that
the material in the form of thin layers will be caused, in passing downward through
the apparatus, to partake of zigzag paths and to meet, in the travel of said
material, currents of hot air or combustion gases or both, by means of which
moisture will be expelled from the material, a distributer at the top of said dryer
for subdividing the material into thin even streams, one or more of the sets of
deflecting plates being arranged to be shaken so as to prevent the accumulation of
material thereon, a furnace located at the side of said drying chamber, a stack
connected to said furnace with branch flues leading into the drying chamber, air
openings leading into the furnace, and a cover for the stack, substantially as set
forth.
Dated this 10th
1000
HARRIS & MILLS,
23, Southampton Buildings, London, W.C., Agents.