Improvements in Apparatus for Drying Semi-liquid, Granular, or Pulverulent Substances.
Year: 1890

page_text: Date of Application, 15th Oct., 1890
Complete Specification Left, 14th July, 1891-Accepted, 22nd Aug., 1891
PROVISIONAL SPECIFICATION.
Improvements in Apparatus for Drying Semi-liquid, Granular, or
Pulverulent Substances.
I, JOHN DUNN, of Ramsay Lodge, Kelso, in the County of Roxburgh, North
Britain, Manufacturer, do hereby declare the nature of this invention to be as follows,
that is to say:-
:-
My said invention has for its object to improve the construction and operation
of apparatus for drying semi-liquid, granular, or pulverulent substances.
In carrying out my invention 1 employ a closed vertical cylindrical vessel in
which a vacuum is maintained by means of pumps or other suitable apparatus.
The lower part of the vessel and the bottom are made with a jacket space for
steam; and in the upper part there are a number of rotating disks fixed on a central
vertical shaft which extends through a stuffing box in the bottom of the vessel and
is driven by means of external gearing. The disks are of two kinds placed
alternately. One kind of somewhat smaller diameter is made hollow for steami
which has access by the central shaft, made hollow for the purpose.
The other kind of disk of somewhat larger diameter is made with a vertical
flange or rim at its outer edge and with a number of openings close to the centre.
These larger disks might be heated with steam but that is believed to be un-
necessary as heat will be radiated down upon them from the under sides of the
other disks. Above each disk there is a stationary arm carrying a series of blades
the bottom edges of which almost touch the top surfaces of the disks, and which
are adjustable in suitable angular positions. The topmost disk of the series is by
preference one of the steam-heated smaller one; and the substance to be dried is
led on to its central part. As the disk rotates the substance carried round by
it encounters the stationary blades, which for this disk are inclined so as to cause
the substance to move outwards, and the substance in time drops over the edge to
The blades for this and
the next lower disk which is one of the larger ones.
every other larger disk are set to cause the substance as it is carried round to be
gradually moved towards the centre, at which part it falls through the openings
down upon the next lower disk which is a smaller one, and on which the substance
is moved outwards again. The number of the disks may be varied in different
cases, but whatever be the number the substance whilst being carried round on all
is moved outwards and inwards alternately on the successive disks, until it reaches
the lower part of the vessel, where it may be allowed to accumulate to any suitable
depth whilst being subjected to the final drying action of the heat from the steam
jacket. In the lower jacketed space the materials are kept stirred and in a circulating
condition by upper and lower sets of arms fixed on the central vertical shaft, on set
of these arms, the lower set for example, being convexly curved so as to move
the materials outwards, the other set being concavely curved so as to move the
materials inwards.
The arms carrying the stationary blades are by preference fixed to vertical
frame bars placed within the vessel, and to the tops of these above the disks there
is fixed a cross frame with four or other number of arms which cross frame supports
the upper bearing and a stuffing box for the central shaft, and also sustains the
cover or top end of the vessel.
Appliances of any suitable known kind are provided for admitting the substance
to be dried to the top of the vessel, and for discharging it from the bottom when
dried; such appliances being such as to avoid the admission of air as completely as
possible. In one arrangement a cylindrical barrel is fitted to rotate as tightly as
possible in a casing provided with a renewable brass or other suitable lining. The

page_text: barrel has formed in its surface one or more cavities.shaped somewhat like the
cavity of an ordinary speon-that is-without corners or parts liable to retain moist
materials; and cach cavity when it is uppermost gets filled from a hopper in the
case of the admission apparatus and from the interior in the case of the discharging
apparatus, the materials dropping out of each cavity when in its lowermost
position.
Dated this Fourteenth day of October 1890
EDMUND HUNT,
Applicant's Agent.
COMPLETE SPECIFICATION.
Improvements in Apparatus for Drying Semi-liquid, Granular, or
Pulverulent Substances.
I, JOHN DUNN, of Ramsay Lodge, Kelso, in the County of Roxburgh, North
Britain, Manufacturer, do hereby declare the nature of this invention and in what
manner the same is to be performed, to be particularly described and ascertained
in and by the following statement, that is to say:-
My said invention has for its object to improve the construction and operation of
apparatus for drying semi-liquid, granular, or pulverulent substances.
In carrying out my invention I employ a closed vertical cylindrical vessel in which a
vacuum is maintained by means of pumps or other suitable apparatus. The lower
part of the vessel is heated by steam admitted into a space under the bottom, and
in the upper part there are a number of rotating disks fixed on a central vertical
shaft. The disks are of two kinds placed alternately; and such that the substances
to be dried and which are fed in at the top of the vessel are moved inwards and
outwards alternately on the successive disks by means of stationary inclined blades,
the substances when moved inwards descending through a central opening to the
next lower disk, and when moved outwards descending over the outer edge of the
disk to the next lower disk. The disks are made with internal spaces and arrange-
ments are made for heating them by steam admitted into such internal spaces; or
only alternate disks may be heated in this way.
My improved apparatus, including improvements in details not so far mentioned
is hereinafter particularly described with reference to an accompanying sheet of
explanatory drawings.
Figure, 1, of the drawings is a vertical section, Figure, 2, is a horizontal section
as at the upper part of the apparatus, and Figure, 3, is a horizontal section as at
the lower part. Figure, 4, is an enlarged elevation of one of the inclined
blades and Figures, 5, and 6, are a plan and a horizontal section of the feeding
apparatus.
In these drawings the same reference mumerals are used to mark the same or
like parts wherever they are repeated.
The vessel consists of an upper part, 7, made with iron or steel plates and a lower
part, 8, made of cast iron, the bottom being formed with recesses, 9, on its under
side which are closed by a base plate, 10, and into which steam is admitted to heat
the lower part of the vessel. A pipe, 11, fixed to the top of the vessel connects
the interior with the pump or apparatus employed to produce a vacuum and to
exhaust the vapors evolved from the substances which are being dried. In the
axis of the vessel and extending through stuffing boxes, 12, 13, at the top and
bottom, there is a vertical shaft, 14, supported by a footstep bearing, 15, at its
lower end, and driven by means of a bevil wheel, 16, fixed on it. The shaft, 14, is
built up with short lengths and other parts, some of which are formed with arms,
and flanges 17, to carry hollow disks, 18, 19, these disks being of two kinds placed
alternately. The disks, 18, of one kind are made of larger diameter than the others,
and with central openings, 20, the other disks being made without central
openings. The vertical shaft, 14, is hollow, and the part on which the

page_text: disks, 18, 19, are fixed is made with two passages, 21, 22, one of which, 21, is
at its upper end in communication with the interior of the highest part of the
shaft, which has a steam pipe, 23, connected to its upper end through a stuffing
box, 24. The steam supplied through the pipe, 23, has access from the passage, 21,
through passages in the arms, 17, and parts supporting the disks, 18, 19, with the
internal spaces of those disks; and these internal spaces also communicate by
other passages in the arms and supporting parts, 17, with the second passage, 22,
in the shaft, 14. Water due to condensation in the disks passes off by the
lást named passages and down the passage, 22, to the lower end of the shaft, 14,
and thence by a pipe, 42, to a steam trap or other suitable discharge apparatus.
On
The substance to be dried is fed in at the top of the vessel through a rotating
feeder, 25, hereinafter described, so as to fall upon the outer part of one of the
larger disks, 18; and as the substance is carried round by the disk it at one part
encounters a series of stationary blades, 26, which are inclined, in plan, in a manner
to guide successive portions of the substance inwards towards the centre.
reaching the central opening, 20, of the disk, 18, the substance falls through to the
next lower disk, 19, which has no central opening; and on this disk, 19, the
substance as it is carried round encounters stationary blades, 27, which are inclined
in plan, in a manner to guide successive portions of the substance towards the outer
edge of the disk, over which edge the substance falls to the next lower disk, 18.
On the disk, 18, just referred to the substance moves inwards again, then outwards
on the next lower disk, 19, and so on alternately inwards and outwards until it falls
from the lowest disk into the lower part, 8, of the vessel. The several sets of
inclined blades, 26, 27, are adjustably fixed to horizontal arms, 28, which are
bolted to vertical bars, 29. There are four of these vertical bars, 29, which are
at their lower ends fixed to flanges, 30, formed on the sides of the lower part, 8,
of the vessel, their upper ends having fixed to them a crosshead frame, 31, which
sustains the cover or top of the vessel and supports the upper bearing and stuffing
box, 12, of the shaft, 14, which is adjusted centrally by screws, 32, screwed through
the central boss of the frame and bearing on the outside of the stuffing box, 12.
Each disk, 18, 19, has only one set of the inclined blades, 26, 27, acting on it.
One of the inclined blades, 26, is shown enlarged in Figure, 4; it is jointed to a
stud, 33, near its back end, and near its front end is guided by a grooved stud, 34.
With this construction each blade is free to move so as to get over any slight
irregularity or obstruction upon the surface of the disk.
The feeder shown in cross section in Figure, 1, and in plan and horizontal
section in Figures, 5, and 6, consists of a cylindrical barrel, 25, fitted to rotate as
tightly as possible in a casing, 35, made in under and upper halves with flanges
for bolting together, and with vertical end covers. A lining shell, 36, of brass or
other suitable material is interposed between the casing, 35, and the barrel, 25,
this shell, 36, having a narrow strip cut away at one part to allow of its being
readjusted for wear by compressing it by screwing the halves of the casing, 35,
closer together. The barrel, 25, has formed in its surface one or more cavities, 37,
shaped somewhat like the cavity of an ordinary spoon, that is, without corners or
parts liable to retain moist materials; and cach cavity, 37, when it is uppermost
gets filled from a hopper, in the case of the feeder or admission apparatus, the
substance or materials dropping out of cach cavity when in its lowermost position.
In the lower part, 8, of the vessel the materials are kept stirred and in a
circulating condition by upper and lower sets of arms, 38, 39, fixed on the
central vertical shaft, 14, one set of the arms the lower set, 39, for example,
being convexly curved so as to move the materials outwards, and the other
set, 38, being concavely curved on the side facing in the direction of rotation, so
as to move the materials inwards. The materials are allowed to accumulate to
any suitable depth in the lower part, 8, of the vessel, and are therein subjected
to the final drying action of the heat from the steam in the bottom spaces, 9, being
finally discharged through an outlet, 40, in connection with which there is fitted a
barrel, 41, constructed and arranged like the feed barrel, 25, so as to prevent

page_text: ingress of air as completely as possible whilst transferring successive small portions
of the materials to its under delivery side.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :
1. The combination of parts constituting as a whole my improved apparatus
for drying semi-liquid, granular, or pulverulent substances, substantially as herein-
before described.
2. In vacuum drying apparatus the combination in a closed vessel of an upper
part in which are arranged rotating disks all or some of which disks are steam
heated together with stationary inclined guide blades for gradually moving the
materials inwards and outwards on alternate disks, and a lower part heated by
steam in bottom spaces and having arranged in it rotating stirrers substantially as
hereinbefore described.
3. The improved construction of the feeding and discharging apparatus (25, 41)
substantially as hereinbefore described and as shown in the accompanying
drawings.
4. The combination of concave and convex stirrers (38, 39) shaped respectively
to move the materials inwards and outwards and produce circulation substantially
as hereinbefore described.
Dated this Thirteenth day of July 1891.
EDMUND HUNT,
Per pro David Ferguson,
Applicant's Agent.