Improvements in Apparatus for Drying or Evaporating Viscous, Semi-solid, or other Materials at Low Temperatures.
Year: 1894

page_text: Date of Application, 6th Jan., 1894
Complete Specification Left, 8th Oct.. 1894-Accepted, 17th Nov., 1894
PROVISIONAL SPECIFICATION.
Improvements in Apparatus for Drying or Evaporating Viscous,
Semi-solid, or other Materials at Low Temperatures.
I, JAMES BINGHAM ALLIOTT, of Bloomsgrove Iron Works, Nottingham,
Engineer, do hereby declare the nature of this invention to be as follows:—
My invention has reference to drying or evaporating at low temperatures and
more particularly to the so drying or evaporating of viscous or semi-solid materials,
or such materials as from their physical condition either do not readily transmit
heat or do not readily permit the escape of vapour, for which purpose I subject the
material that is to be dried in a vacuum or partial vacuum to heat and motion so
that fresh portious of it are being intimately brought into contact with the heating
media and exposed to conditions favourable to the removal of vapour.
A convenient construction of apparatus for the purpose comprises a jacketted
vessel cylindrical or nearly so in form having its axis horizontal or inclined and
provided at one end with a hollow shaft securely attached to the jacketted cylinder
in such a way that it can be used to introduce steam or other heating medium into
the jacket of the jacketted cylinder and for removing any water of condensation or
other fluid therefrom.
One end
The hollow shaft is supported in suitable bearings and provided with driving
gear by which it is caused to rotate the jacketted cylinder revolving with it.
Within the hollow shaft is a pipe passing through it from end to end.
of this pipe passes through the jacket and opens into the central part of the end of
the jacketted cylinder making a close joint with the inner shell of this cylinder.
The other end of this pipe projects beyond the end of the hollow shaft and is in
communication with a condenser and air pump, for producing a vacuum within the
cylinder. Suitable arrangements are made for closing the end of the hollow shaft
around the pipe.
The hollow shaft is provided with means for introducing steam or other heating
medium into it and so into the jacket surrounding the cylinder and of removing
water of condensation or other liquid or air from it.
The jacketted cylinder is provided with a large opening or manhole in the end
opposite the hollow spindle and pipe, through which opening the interior of the
cylinder can easily be examined and thoroughly cleaned. The charge of material
to be treated is usually introduced through this opening but in some cases a
connection with cock or other means of closing it is attached to the revolving
cylinder for enabling material to be heated to be drawn into it without opening the
cylinder or destroying the vacuum existing in it.
The jacketted cylinder is usually provided with a discharge opening perforating
one of its sides in any suitable position with a vacuum gauge and with sight and
light glasses for observing the quantity and condition of the material within it.
The end of the vacuum pipe opening into the cylinder may in some cases be
partially closed by means of strainers of cotton wool or other suitable material,
with the object of preventing fine dust being drawn through it to the vacuum
pump.
When it is desired to keep down the heat in the jacket to a temperature lower
than that of steam at atmospheric pressure I admit steam into it through a reducing
valve so arranged as to work below atmospheric pressure, and I withdraw air and
water of condensation from the jacket either by means of a small auxiliary air
pump supplemented in some cases by a condenser; or by means of the air pump
In either case precautions
producing a vacuum in the jacketted cylinder itself.

page_text: must be taken to prevent the withdrawal of too much steam from the jacket and
consequent undue reduction in the temperature and pressure of steam in the
jacket.
In some cases hot water or other liquid may be used in the jacket for the purpose
of heating the cylinder, suitable divisions being arranged in the jacket and hollow
spindle so as to permit a steady flow of the hot liquid through them.
Dated this 6th day of January 1894.
W. LLOYD WISE,
46, Lincoln's Inn Fields, London, W.C., Chartered Patent Agent.
COMPLETE SPECIFICATION.
Improvements in Apparatus for Drying or Evaporating Viscous,
Semi-solid, or other Materials at Low Temperatures.
I, JAMES BINGHAM ALLIOTT, of Bloomsgrove Iron Works, Nottingham,
Engineer, 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 :-
My invention has reference to drying or evaporating at low temperatures, and
more particularly to the so drying or evaporating of viscous or semi-solid materials,
or such materials as from their physical condition either do not readily transmit
heat, or do not readily permit the escape of vapour, for which purpose I subject
the material that is to be dried to the action of a vacuum or partial vacuum, and to
heat and motion so that fresh portions of it are constantly being intimately brought
into contact with the heating media and exposed to conditions favourable to the
removal of vapour.
A convenient construction of apparatus for the purpose comprises a Jacketted
vessel cylindrical or nearly so in form having its axis horizontal or inclined and
provided at one end with a hollow shaft securely attached to the jacketted cylinder
in such a way that it can be used to introduce steam or other heating medium into
the jacket of the jacketted cylinder and for removing any water of condensation or
other fluid therefrom. The hollow shaft is supported in suitable bearings, and
provided with driving gear by which it is caused to rotate, the jacketted cylinder
revolving with it.
Within the hollow shaft is a pipe passing through it from end to end. One end
of this pipe passes through the jacket and opens into the central part of the end of
the jacketted cylinder making a close joint with the inner shell of this cylinder.
The other end of this pipe projects beyond the end of the hollow shaft and is in
communication with a condenser and air pump for producing a vacuum within the
cylinder. Suitable arrangements are made for closing the end of the hollow shaft
around the pipe.
The hollow shaft is provided with means for introducing steam or other heating
medium into it and so into the jacket surrounding the cylinder and for removing
water of condensation or other liquid or air from it.
In the accompanying drawings,
Fig. 1 shows in longitudinal vertical section, drying or evaporating apparatus
constructed according to this invention;
Fig. 2 is an end view of the apparatus to a smaller scale.
Figs. 3, 4 and 5 show respectively in side elevation, end elevation and plan, the
general arrangement of plant comprising several drying or evaporating vessels
according to this invention.
Fig. 6 is a detail view.
The remaining figures are hereinafter referred to.
Referring to Fig. 1 of the drawings, 1 is a jacketted vessel cylindrical or nearly

page_text: so in form arranged with its axis horizontal and secured to one end of a horizontal
hollow driving shaft 2. This shaft, which is in free communication at its forward
end with the jacket 1 of the cylinder 1 is mounted in a bearing 3 and extends
through a stuffing box 4 carried by a standard 4, into a chamber 5 which is
provided with an inlet pipe 6 for steam, and an exit pipe 7 for water of condensation
which in the arrangement herein described and shewn finally escapes through an
auxiliary air pump, hereinafter referred to, or it may escape through some other
suitable device. 8 is a bent pipe fixed in the jacket 1 of the cylinder 1 so as to
serve as a discharge pipe for the water due to condensation of the steam admitted
to the said jacket. For this purpose one end 8* of the pipe 8 is enlarged to form a
scoop or funnel terminating near the outer wall of the jacket so that as it travels
through the lower portion of its circle of rotation, water of condensation will enter
it and be discharged through the other bent end 8 of the pipe into the hollow
shaft 2 through which the said water of condensation is led to the chamber 5 and
thence to the exit pipe 7. In order that the water may flow more readily away
through the hollow shaft 2 and not fall back again into the jacket 1* the space
between the inside of 2 and the outside of 13 is closed at the part where 8b delivers
water into 2 by a partial diaphragm 8°. 9 is a worm wheel mounted to rotate upon
the shaft 2 with which it is arranged to be connected by a clutch 10 feathered on
the said shaft and operated by a lever 11 (Fig. 6). 12 is a worm for rotating the
worm wheel.
13 is a pipe extending through the hollow shaft 2, one of its ends
passing into the cylinder 1, with which it makes a close joint at 13, and the other
end passing through stuffing boxes 14, 14ª into a coupling pipe 15.
This coupling
pipe is connected, usually by means of a valve 15º, to a pipe 16 that is common to
the pipes 13 of all the drying or evaporating cylinders where several of such
cylinders are combined together as shown in Figs. 3, 4 and 5. To the pipe 16 is
connected the upper ends 17 of the coils of a condenser 18, the lower end of such
coils being connected to a suction pipe 19 in connection with an air pump 20 as
shown in Figs. 3, 4 and 5. The communication between each pipe 13 and the
pipe 16 is controlled by a valve 21. By the arrangement described, when the air
pump is in action a partial vacuum will be set up in the cylinder 1 which will
facilitate the drying or evaporation of the material that is subject in such cylinder
to heat and motion, the vapour generated in the said cylinder being drawn off and
condensed in its passage through the coils of the condenser.
The jacketted cylinder 1 is provided with a large opening or manhole 1' in the
end opposite the hollow shaft 2 and pipe 13, through which opening the interior of
the cylinder can easily be examined and thoroughly cleaned upon removing the
door 1. The charge of material to be treated is usually introduced through this
opening, but in some cases a connection, with cock or other means of closing it, is
attached to the vessel for enabling material to be heated to be drawn into it, by
reason of the vacuum set up in the cylinder by the air pump 20, without opening
the cylinder or destroying the vacuum existing in it.
The jacketted cylinder 1 which may be lagged as at 1* with material that is a bad
conductor of beat, is usually provided with a discharge opening 1ª perforating one
of its sides in any suitable position and normally closed by a cover 1*; also with a
vacuum gauge, and with sight and light glasses for observing the quantity and
condition of the material within it.
The end of the vacuum pipe 13 opening into the cylinder may in some cases be
partially closed by means of a strainer of cotton wool or other suitable material,
with the object of preventing fine dust or particles of liquid being drawn through it
to the vacuum pump.
In the example shown, the strainer consists of a layer 21 of
cotton wool held between perforated plates 22, 22" within a holder 23 that is
adapted to be pushed tightly over the projecting end of the vacuum pipe 13 and is
provided with a handle 23 to permit of its being easily withdrawn from said pipe
after removing the door 1° from opposite the opening 15.
When it is desired to keep down the heat in the jacket to a temperature lower
than that of steam at atmospheric pressure, I admit steam into it through a

page_text: reducing valve so arranged as to work below atmospheric pressure, and I withdraw
air and water of condensation from the jacket through the exit pipe 7, (or through
each of the pipes 7 and a pipe 7* common to them when there are several cylinders 1)
either by means of a small auxiliary air pump 24, as shown in Figs. 3, 4 and 5,
supplemented in some cases by a condenser 25; or by means of the air pump 20
used to produce a vacuum in the jacketted cylinder 1. In either case precautions
must be taken as for example by means of a valve 7 on the pipe 7, or each pipe 7,
as the case may be, to prevent the withdrawal of too much steam from the jacket 1°
and consequent undue reduction in the temperature and pressure of the steam in
the jacket.
To reduce the pressure of the steam admitted to the jacket of the cylinder 1,
I have used a reducing valve of known kind, and such as shown in Fig. 7, in which
the valve or diaphragm spindle 26 is usually pressed upward by an adjustable
spring 27 through a rod 28 and a lever 29 pivoted at 29; and in order to adapt
such a valve to reduce the pressure of the steam to a point below that of the
external atmosphere, I have extended the lever 29, as shown in dotted lines at 29*,
and provided it with an adjustable weight 30 so that the spindle 26 will be subjected
to a downward pressure instead of an upward one.
In some cases hot water or other liquid may be used in the jacket for the purpose
of heating the cylinder, suitable divisions being arranged in the jacket and hollow
spindle, so as to permit a steady flow of the hot liquid through them.
A suitable construction for this purpose is shewn in vertical section in Fig. 8
and in cross section in Figs. 9 and 10, these latter figures being taken on the
lines x and y y respectively of Fig. 8.
In this construction the shaft 2 is provided with two internal longitudinal ribs 31
and 32 that bear against the inner tube 13 and form therewith and the shaft, two
nearly semi-annular passages 33, 33", one of which is in communication with a
liquid supply pipe 6° through a passage 34 and an annular recess 34" in the shaft 2,
and the other with the chamber 5 and exit pipe 7°. The jacket 1 is provided
with corresponding divisions 35, 35* that divide it into two passages 36, 36° which
communicate with the passages 33, 33ª respectively at one end, and with each
other at the other end.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
1. For drying or evaporating viscous, semi-solid or other materials at low
temperatures, apparatus comprising a jacketted cylinder arranged with its axis
horizontal or inclined and carried at one end of a hollow rotary driving shaft
through which a heating medium can be introduced into and discharged from its
jacket, whether or not the said cylinder be provided with a manhole and door at
the end opposite to that connected to the said shaft, an air pump and condenser in
communication with the interior of the said cylinder by means of a pipe passing
through the hollow shaft, and means for rotating the said cylinder and attached
parts, the arrangement being such that material to be dried can be subjected in a
vacuum or partial vacuum to heat and motion, substantially as herein described for
the purpose specified.
2. Apparatus of the kind referred to in the preceding claim, wherein a reducing
valve is provided to admit steam to the jacket of the cylinder at a pressure below
that of the external atmosphere, and air and water of condensation are withdrawn
from the jacket, either by a small auxiliary air pump, with or without a condenser,
or by the air pump that produces a vacuum within the jacketted cylinder itself, the
arrangement being such as to prevent undue reduction in the temperature and
pressure of steam in the said jacket, substantially as herein described.
3. Apparatus of the kind referred to in Claim 1, in which divisions are arranged
in the jacket and hollow shaft so as to permit a steady flow of hot liquid through
them substantially as herembefore described.

page_text: 4. In apparatus of the kind herein referred to, the combination with the end of
the vacuum pipe opening into the jacketted cylinder, of a detachable strainer or
filter, adapted to prevent fine dust or particles of liquid from being drawn through it
to the vacuum pump, substantially as herein described.
5. Apparatus for drying or evaporating viscous, semi-solid or other materials at
low temperatures, constructed arranged and operating substantially as hereinbefore
described with reference to the drawings annexed.
4. In apparatus of the kind herein referred to, the combination with the end of
the vacuum pipe opening into the jacketted cylinder, of a detachable strainer or
filter, adapted to prevent fine dust or particles of liquid from being drawn through it
to the vacuum pump, substantially as herein described.
5. Apparatus for drying or evaporating viscous, semi-solid or other materials at
low temperatures, constructed arranged and operating substantially as hereinbefore
described with reference to the drawings annexed.
Dated this 8th day of October 1894.
For the Applicant,
W. LLOYD WISE,
46. Lincoln's Inn Fields. London, W.C.. Chartered Patent Agent.
Dated this 8th day of October 1894.
For the Applicant,
W. LLOYD WISE,
46. Lincoln's Inn Fields. London. W.C.. Chartered Patent Agent