Improvements in the Process of and Apparatus for Evaporating or Drying.
Year: 1890

page_text: Date of Application, 10th Dec., 1890
Complete Specification Left, 12th Oct. 1891-Accepted, 10th Mar., 1892
PROVISIONAL SPECIFICATION.
Improvements in the Process of and Apparatus for Evaporating or
Drying.
I, FRANCIS MACDONALD ROBERTSON, of No. 28, Dancer Road, Fulham, in the
County of Middlesex, Gentleman, do hereby declare the nature of this invention to
be as follows:-
This invention relates to improvements in the process of, and apparatus for,
evaporating or drying to be employed in the treatment of sewage, the production
of salt from brine or sea water, the production of sugar, the treatment of cereals
and other materials.
For this purpose, I employ a fixed cylindrical chamber formed of sheet copper, or
other suitable material, and I feed the material to be treated, and which may have
been previously heated, into the cylindrical chamber by any suitable means.
A current of dried air is passed into the cylindrical chamber at the upper part
thereof, and is passed continuously therethrough, and takes up or evaporates the
fluid or moisture within the chamber in the manner hereinafter described.
Through the cylindrical chamber is passed a shaft, which is driven by any suitable
means, and upon this shaft are fixed a number of angularly disposed or screw blades
which closely fit the cylinder and in the revolution of the shaft constantly pass
through the material under treatment and pick up some of the moisture contained
therein, and in the continued revolution of the shaft, expose it to the current of
dried air passing through the cylindrical chamber, thus assisting in the evaporation
of the moisture from the material, and carrying forward the resulting solid or semi-
solid material.
In lieu of employing a number of angularly disposed or screw blades, as above
referred to, we, in some cases, employ one only.
The cylindrical chamber may be surrounded by a steam jacket for the purpose of
bringing the liquid or material to a required temperature.
In some cases, I arrange beneath the cylindrical chamber, and so as to rise
vertically upon the exterior of each end thereof, a narrow trough or conduit, and I
form the bottom of the cylindrical chamber with an opening therein corresponding
with the trough or conduit, and I cover such opening with wire gauze or finely
perforated metal.
The material to be treated, and which may have been previously heated, is fed
into the trough or conduit at one of the vertical ends thereof, and flows along the
trough or conduit and percolates through the wire gauze or perforations, and rises
into the interior of the cylindrical chamber, where it is acted upon by the current
of dried air and the angularly disposed or screw blades, as hereinbefore described.
If desired, the angularly arranged or screw blades may be provided with lifters
to carry up the material into the current of dried air.
Dated this 10th day of December 1890.
VAUGHAN & SON,
Agents for the Applicant.

page_text: COMPLETE SPECIFICATION.
Improvements in the Process of and Apparatus for Evaporating or
Drying.
I, FRANCIS MACDONALD ROBERTSON, of No. 28, Dancer Road, Fulham, in the
County of Middlesex, Gentleman, do hereby declare the nature of this invention, and
in what manner the same is to be performed, to be particularly described and ascer-
tained in and by the following statement:―
This invention relates to improvements in the process of, and apparatus for
evaporating or drying to be employed in the production of salt from brine or sea-
water, the production of sugar, the treatment of cereals, and in connection with the
condenser in distilling, in the manufacture of varnish and colors, in the treatment of
matter, such as sewage, and for other uses.
For this purpose, I employ a fixed cylindrical chamber, formed of sheet copper,
or other suitable material, and I feed the material to be treated, and which may
have been previously heated, or not, as desired, into the cylindrical chamber by any
suitable means.
A current of air, either natural, dried, or heated, enters into the cylindrical
chamber at the upper part thereof, and passes continuously therethrough, and
takes up, or evaporates; the fluid or moisture within the chamber, as hereinafter
described.
Through the cylindrical chamber is passed a shaft, which is driven by any
suitable means, and upon this shaft is fixed a continuous screw of large diameter, or
a number of angularly disposed blades, closely arranged in the form of a screw,
which may be corrugated or plain, and which closely fit the cylinder, and in the
revolution of the shaft, constantly pass through the material under treatment, and
pick up some of the liquid or material contained therein, and in the continued
revolution of the shaft, expose it to the current of air passing through the cylindrical
chamber, thus assisting in the evaporation of the moisture from the material, and
moving forward the liquid or resulting solid or semi-solid material.
The cylindrical chamber may be surrounded by a steam, oil or water jacket, for
the purpose of bringing the liquid or material to, or retaining it at the required
temperature.
If desired, the screw may be provided with lifters to carry up the material, and
expose it to the current of air.
And in order that the said invention may be more clearly understood, and readily
carried into effect, I will proceed, aided by the accompanying drawings, more fully
to describe the same.
DESCRIPTION OF THE DRAWINGS.
Figure 1. is an end elevation of an apparatus constructed according to my
invention.
Figure 2. is a side elevation thereof.
Figure 3. is a longitudinal section taken on the line 1.-1. of Figure 1.
Figure 4. is a longitudinal section taken on the line 2-2 of Figure 5. illustrating a
slight modification, and,
Figure 5. is a transverse section taken on the line 3.-3. of Figure 4.
Referring to Figures 1. to 3., a. represents a fixed cylindrical chamber, which is
formed of sheet copper, or other suitable material, and which is heated from below
by means of any suitable furnace, but I have not thought it necessary to show the
latter.
The material to be treated is fed into the cylindrical chamber through a suitable
feed opening, such as a', by the aid of any suitable conduit, aided, if desired, by a
screw or other conveyor, according to the consistency of the material, and the

page_text: material may be either in a cold state, or it may be previously heated in any suitable
manner, according to its nature.
The material is fed into the cylindrical chamber a. until it is about a quarter full;
the feed is then discontinued, and a current of air, either in a natural condition, or,
which has been previously dried or heated, enters the cylindrical chamber through
the feed opening a' passes continuously through the chamber a., finding an exit by
an exhaust opening a' and, in its course, takes up the fluid or moisture within the
cylindrical chamber a. as hereinafter more fully described.
Through the centre of the cylindrical chamber a. is passed a shaft b., which is
mounted in bearings 6, carried by transverse girders 63, and lubricated by means of
oil feeders ^.
The shaft b. is driven by any suitable means, such as a driving belt from a steam
engine, or other source of power, and upon this shaft b is fixed a continuous screw ',
the blade of which may be either plain or corrugated, and of such a diameter as to
closely fit the cylindrical chamber a., or, in lieu of a continuous screw b¹ a number
of angularly disposed blades, closely arranged in the form of a screw, might, in some -
cases, be employed.
This screw in the revolution of the shaft b., constantly passes through the
material under treatment, and thus takes up a portion thereof, and on the continued
revolution of the shaft b., the material so taken up is exposed to the current of air
passing through the cylindrical chamber a., and the evaporation of the moisture is
thus assisted, whilst, at the same time, the material under treatment is being moved
forward.
In my Provisional Specification, I described the employment in some cases, of a
trough or conduit arranged beneath the cylindrical chamber a., and rising at each
end thereof and communicating with the cylindrical chamber at the bottom thereof,
through an opening covered with wire gauze, or finely perforated metal, and it was
proposed to feed the material to be treated into one end of such trough, permitting
it to rise within the cylindrical chamber so as to be actel upon by the screw b.
One of the principal uses of this trough was to permit the return or circulation of
the material moved forward by the screw b' so that it would be kept continuously
in motion, and caused to circulate from end to end of the cylindrical chamber a.
until the completion of the process.
In practice, I have found certain disadvantages in the employment of the trough
above referred to, and I have obtained the desired circulation by a more convenient
arrangement which gives better results.
This device consists of two tubular conduits a³, which are located upon the exterior
of the cylindrical chamber a. at each side and at the lower part thereof, and com-
municate by ways a' with the interior of the chamber a.
By these means, the material moved forward by the screw b will be caused to
circulate in a better manner than by the employment of the trough hereinbefore
referred to, and, inasmuch as the tubular conduits a* are placed at or about a
level with the bottom of the chamber a., no part of the material can escape the
action of the screw b¹.
In some cases, it may be desirable to employ screw conveyors located within the
tubular conduits a³, and driven in an opposite direction to that of the screw b¹ in
order to maintain the circulation of the material under treatment when through
evaporation or otherwise, it is of such a consistency that it will not readily flow
without assistance.
After the material has been subjected to the treatment above described for the
requisite time to attain the result desired, it may be removed through a door a
provided for that purpose, or by other suitable means, a gauge or level a** being
provided at the opposite end of the chamber a. to indicate the level of the contents
thereof.
If desired, the screw 6 in addition to its blade or blades, may be provided with
lifters (not shown) to carry up the material into the current of air passing through
the chamber a. into position to be directly acted upon thereby, and, in some cases, a

page_text: blowing or exhausting apparatus may be employed in connection with either of the
openings a¹ or a² in order to assist the passage from the cylindrical chamber a. of
the current of air charged with moisture.
In the modification represented at Figures 4 and 5, the tabular conduits a³ are
dispensed with, and in lieu thereof, a cylinder a* the lower part of each end of
which is left open, is arranged centrally within the chamber a., and within this
cylinder a works the screw ', but otherwise, the apparatus is similar to that
hereinbefore described.
In this last described example, the screw b¹ constantly moves the material forward
through the cylinder a*, whilst such material returns along the sides and beneath
the bottom thereof, and re-enters at the opposite end, and thus a constant circulation
is maintained as hereinbefore described, and in this case also, any suitable conveyor
may, when necessary, be employed to assist the return of the material.
Apparatus constructed in accordance with the modification lastly described will
be found specially suitable for use in distilling operations.
The cylindrical chamber a. may, if desired, be surrounded by steam, oil, or water
jacket for the purpose of bringing the material under treatment to, or maintaining
it at, the requisite temperature.
By the above means, I can evaporate water or other liquids freely at a lower
temperature than boiling heat, and, at boiling heat, much more rapidly than by the
ordinary methods, the action of the revolving screw being to assist the passage of
the current of air through the cylinder and to bring the air during its passage into
such intimate contact with the liquid to be evaporated or material to be dried, that
evaporation takes place with great rapidity, the liquid to be evaporated or the
material to be dried being constantly picked up by the blade or blades, and thus a
largely extended surface for evaporation is secured.
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 hereinbefore described process of evaporating or drying, consisting in
placing a quantity of the material to be treated within a closed vessel, and passing
a current of natural, dried, or heated air therethrough, whilst, at the same time,
continuously exposing fresh portions of the liquid or material upon the extended
surface of the screw to the action of such air, substantially as hereinbefore
described.
2. An apparatus for evaporating or drying, consisting of a closed chamber,
provided at its upper part with an inlet and an outlet, a continuous screw of large
diameter, or a number of angularly disposed blades closely arranged in the form of
a screw, located within such chamber and capable of rotation and means for permitting
the circulation of the material under treatment, substantially as herein shown and
described.
Doted this 10th do of than 1001
VAUGHAN & SON,
Agents for the Applicant.