PROCESS AND APPARATUS FOR DRYING COLOUR-PASTE AND OTHER STRONGLY AQUEOUS MATERIALS
Year: 1885

page_text: COMPLETE
SPECIFICATION.
I, EMIL PASSBURG, Engineer, residing at Moscow, in the Russian Empire, do
hereby declare the nature of my invention for PROCESS AND APPARATUS FOR
DRYING COLOUR-PASTE AND OTHER STRONGLY AQUEOUS MATERIALS, and in what
manner the same is to be performed to be particularly described and ascertained
in and by the following statement:-
The present invention, like that described by the specification of Letters Patent
No 6326; dated the 12th of April 1884, relates to the drying in vacuo of strongly.
aqueous materials, and especially of materials which owing to the want of stability
of their constitution would be injured or destroyed by high temperatures.
In order to facilitate the transmission of heat to the bodies to be dried in the
vacuum apparatus, heat magazines, as described in the specification of the said
prior patent, may be introduced into the apparatus.
The present invention chiefly consists in a method of continuously guiding the
materials to be dried, along the inner walls of the heated vacuum receptacle, so as
to procure a direct transmission of the heat necessary for evaporation, and to cause
a continual change of place, in order to prevent the burning of the materials on
the hot walls of the receptacle.
For this purpose I employ by preference a revolving vacuum receptacle, heated
by a steam or water jacket, and hermetically closed against the atmosphere, as well
as against the heating jacket, in a special manner; or I provide inside the vacuum
chamber a system of revolving blades adapted to conduct the materials along the
heating surfaces.
This process and apparatus is chiefly intended for materials formed by a loose
mixture of ingredients, such as colour paste, or granulous materials such as malt,
or bodies which have been mechanically comminuted, such as vegetables.
In describing the apparatus reference will be made to the accompanying drawings
Figs. 9 to 16.
.
The rotation of the apparatus, figs 9-12, or of a part of the same, figs 13-16,
in combination with the leaves or blades of the stirring appliance situated in the
apparatus, causes a continuous agitation of the separate parts of the material to be
Dell

page_text: "
dried, whereby these parts are brought into immediate contact with the heated
metal surfaces, which are continuously supplied with heat from outside, and
transmit the same to the material to be dried."
The apparatus illustrated in Figs. 9 to 16 is worked as follows:
The material to be dried is introduced through the upper manhole of the
apparatus, which is filled to about one third, after which the manhole is closed,
steam turned on, and a vacuum produced by any suitable means, while the
apparatus and thereby the stirring appliance is set in rotation. A rapid and
intense evaporation will soon take place and continue, decreasing towards the end,
until the drying process is terminated.
The termination of the process is indicated by the thermometer t, fig. 9; the
evaporation being completed, the mercury in the thermometer is no longer heated
by the passing vapours, and consequently its temperature falls.
The apparatus should be constructed so as to prevent as much as possible the
ingress of steam into the vacuum chamber, even in case of the leaking of rivetted
joints.
The drying apparatus, figs. 9 to 12, consists of an interior casing A made of
copper or other suitable metal and serving to receive the material to be dried.
The casing A is surrounded by the jacket B made of sheet iron, so as to form a
space between A and B for the circulation of steam or water.
Both casings A and B are closed steam and air tight by means of the bottoms or
covers C and D mounted in the bearings G and H by means of hollow shafts E
and F.
The covers C and D are thus adapted to turn, together with A and B, around the
horizontal axis of the apparatus.
The hollow shaft E, mounted in the bored bearing G (fig. 9) and closed air tight
by the stuffing box c, besides serving as a pivot, forms also a connecting pipe with
the air pump, and is provided in the interior of the apparatus with a cap d which
prevents the lighter parts of the material contained in the cylinder from being
carried off by the action of the air pump. The bearing b is cast in one piece with
a connecting tube e leading to the collector I.
To the outer end of the bearing b is cast a short pipe forming with the gland g
a stuffing box for the steam pipe h.
The tube leads to the tube h¹, and the latter into the heating jacket formed
between A and B.
The tube turning with the apparatus receives steam through the fixed tube i,
screwed on the stuffing box g and connected with the steam conduit.
At the discharge end of the pipe / near the cover C, the pipe h protrudes over
the flange soldered to the same, and is connected at K in such manner to the
exterior section h¹, that in case of a leakage in the screwjoints the steam is not
permitted to enter the apparatus.
The pipe h may, however, pass immediately between the gland c and the cover C
out of the hollow shaft E, and lead into the heating space formed between the
casings A and B. is a lubricator.
The collector or receiver I (fig. 9) consists of a cylindrical vessel connected at m
with the apparatus and at n with the condenser connected with an air pump of
any known construction, and by means of which the vacuum may be produced in
the space enclosed by the casing A and the covers C and D. For preventing the
dust of the dried material from being carried over into the condenser, the upper
part of the receiver I is provided with a strainer p easily accessible through the
lid o, under which there may be a cloth-covered frame r or equivalent appliance.
The accumulated dust may be easily removed through the bottom valve s. t is
a thermometer, u an air valve.
The hollow shaft F, pivoted in the bearing H, has a branch pipe w, to which is
fixed a pipe v serving to receive the exhaust steam from the heating jacket
between A and B,

page_text: The pipe communicates through the shaft F with the exhaust pipe K connected
to the stuffing box z as shown. F carries the loose pulley x and the fixed pulley y
which may be set in motion by any suitable means.
Between the casings A and B are rivetted two grooved man-hole rings packed
with indiarubber.
For preventing the ingress of steam into the drying chamber in case of a leakage
of the rivetted joints, the rivet heads facing the interior are covered with hollow
copper rings securely soldered to the interior of the shell A.
The hand wheel and lever N serve to close the man hole hermetically by means
of the cover O packed with india rubber.
To the inner side of the shell A are fixed the curved blades P P, figs. 9 and 11,
which during the rotation of the apparatus periodically take up and discharge the
material to be dried, so that every particle of the material may be brought into
contact, with the inner surface of the casing A, and may thereby be heated.
These blades P P increase the heating surface like interior heating ribs.
For preventing loss of heat it is advisable to cover the exterior jacket B with a
bad conductor of heat.
This is also the case for the drying apparatus, figs 13-16. The same consists of
a cylindrical casing B, made of sheet iron, and hermetically closed by the covers C
and D. In the interior of the cylinder, thus formed and closed, is placed a rotary
heating body consisting of two convex covers A A screwed and soldered together
with the flat tube plates a a¹ carrying the heating tubes QQ. For the purpose of
giving this system of tubes the necessary rigidity, the plates a a² are connected by
a horizontal shaft T. To the covers A A are rivetted the tubular axles E and F
adapted to turn the system of heating pipes around its horizontal axis and to serve
as inlet and outlet of steam to and from the space enclosed between the bottoms a
and a and to and from the pipes QQ.
The hollow shafts E and F are pivoted in the bearings b b of the covers C and D
and packed by stuffing boxes c. At one end of the heating body the hollow
shaft E, which serves as steam inlet, is connected with the steam conduit i
by means of the stuffing box g so as to permit the rotation of the shaft E round the
end of the pipe i but so as to form a steamtight joint with the same.
The hollow shaft F, serving as outlet for the exhaust steam, is mounted at the
other end of the system of pipes and adapted to turn in the bearing b and gland c.
The shaft F carries the driving pulleys x and y necessary for turning the system of
pipes.
The end of the shaft F has its bearing in the stand H and passes through the
stuffing-box gland e.
The axle bearing of the stand has outside the shaft F a neck z and is connected
with the exhaust pipe K.
On the shaft T, situated in the axis of rotation, are mounted loosely two sections
of pipe U U provided with flanges V V. To these flanges are screwed the sliding
plates W, W, figs. 13 and 16, having a smaller diameter than the cylinder B and
provided with holes corresponding in number and size to the heating pipes QQ.
The sections U U, acting as guides for the sliding plates W W, prevent the
jamming of the plates W W between the pipes QQ, and consequently facilitate a
to and fro motion of the sliding plates on the pipes QQ and on the shaft Y¹.
With the inner flanges I of the sections U U are connected by means of 4 flat
irons y (fig. 15) the rings xx (fig. 13 and 15).
The periphery of these rings carries flanges or seats for the semi-circular
buckets P, P (figs. 13 and 15). The latter are attached to the plates W W and to
the curved flanges of the two rings xx.
When the axles E and F are turned, the interior heating body, the sliding
plates W W, the rings x, x, and consequently also the buckets P P, rotate around
the horizontal axis of the apparatus. The materials to be dried are thereby raised
from the bottom of the apparatus by the buckets P P, and on the further rotation

page_text: +
of the apparatus they fall from the buckets between and on the pipes QQ and are
thereby divided into small portions which are heated on the hot surfaces of the
pipes.
Screwed to the pipes U U at y are two handles z, z¹, (figs. 13 and 15) leading to
the man hole.
The buckets P P being arranged above the rings X X and out of line with each
other, the two systems of buckets may easily be pushed one into the other by
means of the handles z, z¹, in which case the sliding plates W W are at the same
time pushed as far as the man-hole, after which the dried materials contained in
the apparatus may be completely removed.through the lower man-hole.
For the purpose of discharging the water of condensation from the interior of
the heating apparatus, the latter is provided with let-off cocks S situated near the
joint of the casing A with the tube plates a a¹, while opposite the cocks S are
situated the man holes m m provided with airtight covers.
These man holes serve for the removal of materials which may have accumulated
in this part of the apparatus. c¹ is a suction pipe having a cap d and leading to
the receiver I, fig. 9. This receiver is connected (in the same manner as the
apparatus fig. 9) with the condenser and air pump.
The lower man hole cover O is provided on the inside with a slide of sheet iron
(or it may be lined with wood) adapted to prevent the drying material from
accumulating in the man-hole. The apparatus is also fitted with an air-valve,
a thermometer, a lubricator, and a vacuum-gauge.
A simple combination of the two constructions, figs. 9 to 12 and figs. 13 to 16,
may be obtained by soldering the tubular heating body airtight to the covers C
and D, fig. 9, so as to revolve with the whole apparatus round its longitudinal axis.
In this case the shaft T may be dispensed with, and the heating space between
the casings A and B may be omitted or retained. If the heating space is retained,
it is connected with the tubular heating body.
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, I declare that what
I claim is
1. The process of drying colour paste and other strongly aqueous materials
by means of a rotary vacuum apparatus in which they are continually kept
in close contact with the heating surface of the apparatus and at the same time
subjected to a uniform stirring action.
2. A rotary vacuum apparatus, illustrated by Figs. 9 to 12, and consisting
chiefly of a cylinder supported by hollow journals or axles E and F, and heated by
a water or steam jacket, the said apparatus being connected through the hollow
journals with an air pump and with the heating pipes.
3. In rotary vacuum apparatus, substantially as described, a) the use of a
stuffing box with gland c for forming a tight joint between the hollow journal E
and the bearing b; b) a steam conduit composed of a fixed pipe i and a movable
pipe passing through the hollow journal E to the steam jacket and adapted to
revolve with the apparatus; c) the use of a stuffing box with gland g for producing
a tight joint between the steam pipe i and the vacuum space; d) the combination
of exhaust pipe K, hollow journal F, stuffing box Z, and pipe v connected with the
steam jacket.
4. The collector J (illustrated by Fig. 9) interposed between the air pump and
the vacuum apparatus, for retaining any dust or small particles carried off by the
air from the materials to be dried, the said collector being fitted with a strainer, a
.cloth-covered frame or equivalent appliance.
5. The use of buckets or curved blades in the interior of a rotary vacuum
apparatus for automatically stirring the materials to be dried.
6. A vacuum drying apparatus consisting essentially of a cylindrical chamber in
communication with an exhausting apparatus, and a tubular heating appliance
enclosed in the said cylindrical chamber, the said heating appliance being mounted

page_text: on hollow journals leading to the heating conduit and provided with buckets
or curved blades for stirring the material to be dried.
7. The arrangement of sliding plates, adapted to slide in the cylindrical vacuum
chainber, along a system of heating tubes for the purpose of transporting the dried
product towards the lower discharge opening.
8. A vacuum drying apparatus; consisting essentially of a rotary cylindrical
chamber, communicating through one of its hollow journals with an exhausting
apparatus, and containing a tubular heating appliance which communicates through
both journals with the heating conduit and is hermetically closed against the
vacuum chamber.
The whole substantially as described and illustrated.