IMPROVEMENTS IN CONCENTRATING AQUEOUS SOLUTIONS AND THE LIKE, AND IN DRYING THE RESULTANT PRODUCTS, AND APPARATUS THEREFOR.
Year: 1885

page_text: [Communicated from abroad by August Büttner, Manufacturer, and Carl Meyer,
Doctor of Philosophy, both of Merdingen, in the Empire of Germany.]
1, WILLIAM PHILlips Thompson, Fel. Inst. P.A. of the Agency for Foreign Patent
Solicitors, 6 Lord Street, Liverpool, in the County of Lancaster, and 323, High
Holborn, in the County of Middlesex, Civil Engineer, do hereby declare the
nature of the said invention for "IMPROVEMENTS IN CONCENTRATING AQUEOUS
SOLUTIONS AND THE LIKE, AND IN DRYING THE RESULTANT PRODUCTS, AND
APPARATUS THEREFOR. (A communication from abroad by August Büttner,
manufacturer, and Carl Meyer, Doctor of Philosophy both of Merdingen in the
Empire of Germany) and in what manner the same is to be performed, to be
particularly described and ascertained in and by the following statement:-
This invention relates to an improved apparatus for evaporating and inspissating
matters containing more or less humidity, by a direct contact of the same with hot
combustion products, especially with generator gases without indirect heat through
an intermediate metal plate or otherwise. The apparatus is constructed in such a
way that the result is attained in an advantageous manner and the disadvantages,
easily caused by the direct communication of heat, especially burning up will be
avoided.
The fire gases produced in any generator, are first purified from the ash-dust in
the space A. This is obtained by a partition a, hanging from above; the gases
flowing round this partition throw the particles of the ash dust into the funnel
shaped inferior part of this space. They enter then into the evaporator B and
come in contact with the surfaces of a great number of evaporating plates, united
in groups I, II III, IV and so forth. Behind the first two groups and afterwards
behind each of the subsequent ones, partitions 61 62 63 are arranged, and compart-
ments ele e thus formed, through which the liquid entering at c and escaping at d
must flow. The groups I and II are put in an alternating motion (preferably by
means of a crank-contrivance as shewn in the drawing) so that always exactly the
half of their whole surface is submerged. The level of the liquid in the compart-
ment e' (supposing the same quantity of liquid is filled in) is consequently always
in the same height, a temporary rising above the normal level and consequent

page_text: burning of the masses resting above the latter, will thus be avoided. The other
batteries are moved in such a way by eccentrics fƒ³ (see Figure 3) fastened to the
main shaft and working on swinging levers h³ h in such a manner that they
stay, 3, 4 to 6 times longer above the level of the liquid than below it. Their
effect is of course thereby increased in the same proportion. The eccentrics are
disposed on the axle g in such a manner, that always nearly the same number of
plates is submerged; elevation and depression of the level of the liquid is therefore
almost entirely avoided.
As it is important, that the plates always remain covered with a layer of liquid,
the two sides thereof are provided with small rods a¹ a² a³ a a³ riveted upon the
plates for the purpose of lifting a larger quantity of water, than the smooth plates
would do. The distance between the several rods is smaller at the upper part of
the plates than at the lower part, where the distance is increasing. In making
this arrangement it has been taken into consideration, that the upper parts of
the plates become dry, first because they stay longest out of the liquid as well as
because they do not receive any liquid from above, as is the case with the lower
parts of the plates Teeth, notches, or other similar contrivances may also be used
for detaining liquid. The groups of plates are of different height, Nos I and II
are the lowest ones; the height of the following batteries gradually increases.
The plates, which come in contact with the hotter gases, are the shorter ones, so
that the upper parts are less exposed to become dry. The distance of the several
plates in the groups is also different; it is the smallest in I and II according to
the greater dilution of the liquid in the compartment e¹, and it is the greatest
in VI on account of the pasty state of the mass in e³, which renders very difficult
the entrance and exit of plates arranged close to each other, without taking with
them a certain quantity, of the substance.
The partitions b₁ 62 are arranged according to the principle, that always the
thicker part of the liquid passes into the subsequent compartment. In the
beginning this portion of the liquid generally lies below; the partition 6¹ allows
therefore the liquid to escape below. In the subsequent compartments the
thickest mass is on top, because it has become inspissated, and the separation by
gravity is hindered by the thicker consistency. The mass flows therefore over
the partitions b² 6³ b¹.
The hotter generator-gases thus come in the place B (besides with the upper
ceiling walls, which here need not be taken into consideration) exclusively in
contact with surfaces of liquids which are constantly changed. A rising and
falling of the level of the liquid is entirely avoided in the compartment e¹, where
it is the most important, and almost entirely in the subsequent compartments,
which prevents the pasty mass from burning. Another advantage of this con-
struction is that the square plates being only suspended and requiring therefore no
rigidity, may be made of any material, especially of fragile, flexible and expensive
material, as for instance of glass, earthenware, impregnated paper or texture, thin
sheets of lead, tin or platinum or other suitable material. It is evident, that this
is of the greatest importance for the manipulation of many chemical solutions or
other substances which react on the usual materials employed for the purpose.
When the mass in the hearth is inspissated, so that it does flow no more, but has
become stiff, it is introduced into the dryer c by the worm h. The dryer consists
of cylinders m m³, n n¹ arranged in couples; axles provided with shovels set
diagonally to the axle move therein in such a way, that the shovels catch one into
another. Each shovel thus throws the substance before it into the other cylinder
in the direction of the axle. The mechanism is preferably arranged so that the
substance is divided as small as possible and will fill up the space of the cylinder,
whereby the most intense effect of the current of dry air is ascertained.
The motion of the shovels is so arranged, that it corresponds to the height of
projection up to the ceiling of the cylinders. The shovels are furthermore provided
of a certain length with teeth z z passing through a rack y (Figure 1) The bulk
of the pasty substances when becoming dry, balls up into large spherical elastic

page_text: lumps, in which state they offer not only a very small surface but their interior is
also entirely protected from the drying effect of the air current.
These balls are cut into pieces by the teeth and racks. But a fixed rack would
have the inconvenience, that solid deposits of the mass would be agglomerated
before the several teeth; the rack is therefore displaced one tooth each time during
each rotation of the axle. When the rack has been displaced, a shovel, the teeth of
which are displaced one tooth carries the deposit away. The displacement of the'
rack is effected as shown in Figure 1 by means of a tappet turning with the axle.
In order to reduce the smaller balls, grains etcetera, the mass in a suitable
stage of its passage through the drying cylinders is passed through a special
disintegrator p. To this purpose the mass is stretched by the worm o (Figures
and 2) passed through the disintegrator p (Figure 2) and by the latter redelivered
into the drying apparatus. The mass may suitably be reduced when it is passing
from the upper couple of cylinders to the lower one. A current of hot air taken
from the heater L is passed through the drying cylinder. Gases from the hearth B
or generator gases may also be mixed with this air or the generator gases may be
used alone.
As the transmission of heat according to the principle of this invention is not
effected through walls, but directly from the hot gases to the material to be dried,
the walls of the dryer c (especially the cylindrically shaped beds for the material to
be dried) may advantageously be made of masonry, cement, earthenware and the
like, as is the case with the inspissating apparatus.
According to the substance to be treated, only the apparatus B with accessory or
only the apparatus C with accessory may be used. The apparatus B alone is
employed when the liquid is only to be inspissated or concentrated, and the
apparatus C when pasty or semi fluid substances are to be dried.
The apparatus is preferably so proportioned that the material to be dried leaves
the drying cylinders by the worm z in the form of a dry powder,
Having now particularly described and ascertained the nature of the said
invention, and in what manner the same is to be performed, as communicated to
me by my foreign correspondents, I declare that what I claim is
1st. In order to avoid the introduction of impurities and the burning or
carbonizing of the mass during the process of concentrating aqueous solutions to
a pasty substance by means of hot gases (direct fire gases) acting exclusively by
direct contact with the surfaces of the said mass and for the purpose of assuring
advantageous work, the application of the following construction:
a) A contrivance for separating the ash dust consisting of a large intermediate
chamber provided with a partition.
b) The division of the evaporating hearth in several compartments by partitions b
arranged in such a way, that principally the thicker parts of the mass flow over
into the subsequent compartments.
c) The arrangement in each compartment of an evaporating mechanism consisting
of plates which can be set in alternating motion; the first compartment being
provided with two evaporating mechanisms.
d.) The above described evaporating mechanism consisting essentially of
rectangular plates, capable of motion vertically up and down thereby constantly
renewing the level of the liquid preventing the mass from burning up, are pro
vided with the following particular arrangements
a) The plates are arranged more closely in the first groups than in the subsequent
ones.
b) The plates of the first groups are the lowest ones, their height increases in the
subsequent ones.
c) The plates are set in motion by means of eccentrics f and levers h (Figure 3)
in such a way, that they rest a certain length of time longer above the lever than
below it and that moreover the rising and falling of the water level is reduced to a
minimum in spite of the constant agitation of the liquid,

page_text: d) The evaporating plates are provided with rods, ribs, teeth, notches or the
like (a a a a²).
e) The evaporating plates are fixed by suspension so that they may be made of
fragile or flexible material.
2nd. For the purpose of perfectly drying up crumbling masses the application
of hot gases (direct fire gases) acting exclusively by direct contact with the surfaces
of the masses, in combination with the application of axles provided with shovels,
which
a) propel the material to be dried in the direction of the axle in holders which
may be made of clay, cement, earthenware or the like;
b) are provided with a mechanism for reducing the material to be dried, which
mechanism consists of a toothing z of the shovels in combination with the rack y
(Figure 1) displacing itself a pitch one time during one rotation.
Dated this 16th day of May 1885.
WM P. THOMPSON & Co.,
Agents for the Applicants.