Improvements in the Treatment of Solutions or Liquids for the Purpose of Concentration or Evaporation, and in Apparatus therefor.
Year: 1890

page_text: Date of Application, 14th Feb., 1890
Complete Specification Left, 12th Nov., 1890-Accepted, 10th Jan., 1891
PROVISIONAL SPECIFICATION.
Improvements in the Treatment of Solutions or Liquids for the
Purpose of Concentration or Evaporation, and in Apparatus
therefor.
I, ALFRED FRYER, of Wilmslow, in the County of Chester, Engineer, do hereby
declare the nature of this invention to be as follows:-
The invention is especially applicable to the treatment of those solutions or liquids
which are readily injured by heat or which are too viscous to be easily treated by
ordinary methods, though it may also be applied to the concentration or evaporation
of any other liquid containing solid bodies in solution or suspension.
It consists essentially of apparatus for evaporating liquid or viscous substances so
constructed that only a film of the substance is at any one time being evaporated or
dried. This film is heated by heat applied to one side of a plate of metal or other
suitable material while the film itself is in contact with and is dried or evaporated
upon the other side of this plate, the whole being kept at a lower temperature in
consequence of the application of heat to the plate being usually more or less inter-
mittent and of a blast of air being blown over the film. This blast may be of
ordinary air or it may be heated or dried or both. The process is made continuous
if desired by fresh fluid being continually introduced which washes or replaces the
film of liquid under treatment.
In carrying out the invention-which I will herein describe with reference to the
concentration of solutions, I prefer to use a vessel having the bottom made prefer-
ably of metal slightly conical in form or almost flat revolving on an axis so arranged
that the side of this conical bottom which is for the time being the lower side
shall be nearly horizontal.
This metallic conical bottom is provided with a lip, flange, or side, or lips,
flanges, or sides, so arranged as to enable the vessel to contain, when the axis of the
apparatus is so inclined that the lower side of the conical bottom is nearly horizontal,
a suitable quantity of the liquid or solution to be treated. Beneath that portion of
the conical bottom which is lowest and therefore covered with the liquid or solution
to be treated, I place a fire or flame which in some cases, I so arrange as to be
able to regulate its intensity and in some cases I make use of more than one fire.
When the apparatus is at work the vessel with a conical bottom revolves on its axis
and the fire strongly heats that part of the conical bottom which for the time being is
lowest and covered with the liquid or solution to be treated, and as in process of
revolving on its axis each part of the conical bottom in turn occupies the lowest
position, each part in turn is heated by the fire once in each revolution of the axis, or
where more than one fire is in use it is treated once by each fire in each revolution of the
axis. As each part of the conical bottom rises from the lowest position and so is no longer
covered by the body of the liquid to be evaporated, it carries up with it a film of
liquid adhering to its warm surface from which evaporation rapidly takes place. To
facilitate evaporation from this surface as well as from that of the body of liquid
in the lowest part of the conical bottom, I may so arrange a fan as to blow or
draw a current of air over these surfaces, and may also in some cases make use of
one or more additional fires beating other parts of the conical bottom. In some
cases I warm the air to be thus blown or drawn over the evaporating surfaces, and it
may even in some cases be desirable to artificially dry the air which is to be thus
used. I usually so case in the outer part of the conical heated bottom as to prevent
as far as possible the radiation of heat from it, since I desire to use as much of the
heat as possible in evaporating liquid on its inner surface. In most cases I arrange
an opening at or near the centre of the conical bottom of such dimensions and con-
struction that the solution or liquid undergoing concentration may be discharged

page_text: through it by slightly lessening the inclination of the axis of the apparatus, or so
that in the case of a solution undergoing concentration there may, be a continuous
flow of the unconcentrated solution into one part of the apparatus and a continuous
escape of the concentrated solution through the opening. In some cases this opening
may be closed by a plug or in any other convenient way and may be opened to
discharge the concentrated material. In some cases I empty the apparatus of liquid
by slightly increasing the inclination of the axis, so that the liquid or concentrated
solution escapes over the lip surrounding the outer edge of the conical bottom.
As the vessel rotates that part of the vessel which has been heated by the fire
gradually rises from the liquor carrying with it a thin film from the surface of which
evaporation rapidly takes place owing to the heat retained by the vessel and by the
film itself, sometimes accelerated by a current of air passing over it, and sometimes
assisted by the heat from one or more additional fires. As the rotation of the vessel
and the evaporation continue the vessel loses its heat and as the portion of it again
enters the liquor with the residue of the film which was lifted, it first takes heat there-
from preventing a rise of temperature in the mass and is then again reheated and the
operation continued until the required degree of cencentration has been reached.
Instead of heating the bottom of the vessel by a direct fire it may be heated by
steam, by jacketing or forming the bottom of the vessel double and introducing steam
into the space between the outer and the inner shell, arranging suitable connections
for the admission of steam and the removal of condensed water, but the arrangements
remaining in all other respects substantially as already described.
The use of steam heated apparatus, however, is for many purposes not so good as
apparatus heated by a direct fire at some portion or portions of the shell, as the heat
is applied to the whole shell and the cooling of the shell and consequent taking up of
heat from the bulk of the solution to prevent its temperature rising, cannot be
carried on to the same extent.
D
1 11. 1971 J. W 1900
WM. P. THOMPSON & Co.,
6, Bank Street, Manchester, Patent Agents.
COMPLETE SPECIFICATION...
Improvements in the Treatment of Solutions or Liquids for the
Purpose of Concentration or Evaporation, and in Apparatus
therefor.
I, ALFRED FRYER, of Wilmslow, in the County of Chester, 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:
The invention is especially applied to the treatment of those solutions or liquids
which are readily injured by heat or which are too viscous to he easily treated by
ordinary methods, though it may also be applied to the concentration or evaporation
of many other liquids containing solid bodies in solution or suspension.
It consists essentially of apparatus for evaporating liquid or viscous substances so
constructed that only a film of the substance is at any one time being evaporated or
dried. This film is heated by heat applied to one side of a plate of metal or other
suitable material while the film itself is in contact with and is dried or evaporated
upon the other side of this plate, the whole being kept at a comparatively low
temperature in consequence of the application of heat to the plate being usually more
or less intermittent and of a blast of air being blown over the film. This blast may
be of ordinary air or it may be heated or dried or both. The process is made con-
tinuous if desired by fresh fluid being continually introduced which washes off or
replaces the film of liquid under treatment.
The invention will be fully described with reference to the accompanying
drawings which show as an example of it an apparatus arranged for heating by
direct fire.

page_text: Fig. 1. is a side elevation (partly in section) of apparatus for the concentration of
solutions.
Fig. 2. plan of same.
The pan A which receives the liquid or semi-liquid solution is made with the bottom
slightly conical in form and is mounted upon an inclined axis so that the side of
the conical bottom which is for the time being the lower one is almost horizontal.
The metallic bottom A is provided with a lip, flange, or side a to enable the vessel to
contain upon the nearly horizontal part of the bottom a suitable quantity of the liquid
or solution to be treated. It is mounted upon or attached to the shaft B which is
preferably hollow and is as shown inclined until a part of the bottom of the pan
nearly horizontal. The shaft B is carried in suitable hearings C, C which maintain
it and the pan at the required inclination. These may be fixed or may be movable so
that the position or inclination of the pan may be adjusted when desired. The shaft B
is driven by a strap on the pulley D and as it moves the pan A rotates along with it.
To facilitate evaporation from the surface of the liquid or semi-liquid solution I use
a fan E to blow or draw a current of air over the surface. The fan E is preferably
placed above the pan A so as to come into contact with vapour rising from it and to
always keep the air which is in contact with the liquid in motion. It is attached to a
shaft E mounted or carried in the bearings G and provided with a driving pulley H.
The conical pan A and the fan E are both actuated by means of the main driving
shaft I provided with the main driving pulley J. This shaft by means of the bevel
gear K, K' drives the shaft L upon which are fixed the pulleys M for driving the
fan E, and M' for driving the vessel A. The whole apparatus is carried by a suitable
framework N.
The hollow shaft B, carrying the vessel A, is provided with a plug b¹, which may
either be solid, so as to entirely prevent the escape of any liquid when it is in its place,
or may be made hollow and have its sides raised somewhat above the bottom of the
vessel A so as to permit a certain quantity of liquid to be contained in the pan A, but
to allow the liquid within it to overflow and to pass through the hollow plug and
thence through the hollow shaft and so to flow away through the gutter when the
quantity of liquid in the vessel is increased. The liquid is introduced or supplied to
the pan A by a funnel and pipe Q, Q'
Beneath the conical bottom, and usually beneath that portion of it which is lowest.
and therefore covered with the liquid or solution to be treated, 1 place a fire or flame P
which in some cases I so arrange as to be able to regulate its intensity and in some
cases I make use of two or more fires P¹, P. When the apparatus is at work the
pan A rotates on its axis and the fire strongly heats that part of the conical bottom
which for the time being is lowest and covered with the liquid or solution to be
treated, and as in process of rotating on its axis each part of the conical bottom in
turn occupies the lowest position, each part in turn is heated by the fire once in each
revolution of the axis, or where other fires P1, P" are in use it is heated once by each
fire during each rotation. As each part of the conical bottom rises from the lowest
position and so is no longer covered by the body of the liquid to be evaporated, it
carries up with it a film of liquid adhering to its warm surface from which evaporation
rapidly takes place. In apparatus of small size, these fires may suitably be gas jets
since these can quickly and readily be lighted, increased or decreased in intensity or
put out as the condition of the liquid undergoing operation may require. In larger
apparatus fires of coal, charcoal, or coke provided with a blast to increase their
intensity would be suitable.
In working the apparatus the pan A and the fan E are set in motion by the driving
shaft I. It will be observed that the motion given to the vessel A is comparatively
slow while the fan E is driven at a much more rapid speed. The liquid to be con-
centrated is introduced into the pan A through the funnel and pipe Q, Q', in such
quantity that the whole of the lower side of the bottom of this pan is covered with a
small depth of liquid whilst the remainder of the bottom of the pan is only covered by
a film of liquid carried round with the pan as it rotates. The lower side of the vessel
is strongly heated by the fire P, and as the pan rotates, each part of it in succession

page_text: becomes the lowest part, becomes highly heated while covered with liquor and then
passes onward still heated with only a film of liquor upon it. The surface of the
heated liquid and of the film of liquid carried on the surface of the pan is being
continually played upon by the air driven against it by the fan E and evaporation
from its surface is thus rendered much more rapid, while the temperature of both
liquid and pan is kept low. If the liquid should be very viscous and very readily
injured by heat it may be necessary to limit the heat applied to that produced by
the single fire P placed beneath the lowest part of the pan A, but if the liquid should
be more fluid and less readily injured the speed of revolution of the pan A and of
the fan E may usually be so arranged that a second fire, P1, may be made use of,
heating a portion of the vessel which for the time being is only covered by the
comparatively thin film of liquid, and in some cases additional fires, such as P
may also be made use of. It is clear that by the use of these additional sources of
heat the speed of evaporation may be considerably increased. In many cases the flow
of liquid into the vessel may be so regulated that there shall be a continuous outflow
of the concentrated liquid over the raised lip of the plug, while the vessel may be
completely emptied when necessary by removing this plug. In other cases, where a
solid plug is used, the liquid may be carried to the desired degree of concentration
and then discharged by removing the plug. It will usually be found more convenient
to adopt one or other of these methods of discharge than to alter the inclination of
the shaft carrying the vessel A, though the discharge of most of the contents of A
may be effected in that method if desired.
In some cases I heat the air to be blown or drawn over the evaporating surfaces, and
it may even in some cases be desirable to artificially dry the air which is to be thus
used. I usually so case in the outer part of the conical heated bottom as to prevent
as far as possible the radiation of heat from it, since I desire to use as much of the
heat as possible in evaporating liquid on its inner surface.
In some cases the thickened liquid may be allowed to remain upon the bottom of
the vessel until it forms a dry coating upon it, the heating being suitably regulated
and the fan being kept in operation during the process.
When the liquid to be treated is or has become viscous or where it is desirable to
remove the film more rapidly or more effectually from the inner surface of the pan A
than by the washing action upon it of the liquid accumulated at the part which is for
the time being the lowest part of the pan, I arrange a fixed scraper or scrapers
which, by means of the rotation of the pan, scrapes or scrape away the film and
conducts the film so scraped or collected either toward the axis or toward the lip a
of the pan A or over the back edge of the scraper or scrapers as may be desired.
I have described the vessel A as heated by means of fire-heat, but it is obvious
that it might be provided with a steam jacket, and that steam might be introduced
to heat it, either through a pipe carried through the hollow spindle B to which the
pan A is itself attached, or by making the spindle carrying the fan E hollow, and
introducing the steam pipe through that. The methods of thus introducing steam
into a rotating vessel are so well known that it is not necessary here to specify them.
The use of steam heated apparatus, however, is for many purposes not so good as
apparatus heated by a direct fire at some portion or portions of the shell, as the heat
is applied to the whole shell and the cooling of the shell and consequent taking up
of heat from the bulk of the solution to prevent its temperature rising cannot be
carried on to the same extent.
Although I have shown and described a fan as producing a current of air playing
upon the film and the liquid undergoing concentration in the pan A, it is obvious that
a current of air produced in any other suitable way would have the same effect in the
working of the apparatus.
Having now particularly described and ascertained the nature of the said inven-
tion, and in what manner the same is to be performed, 1 declare that what I
claim is:
1. The combination of a rotating concentrating or evaporating pan (heated by fire

page_text: heat acting upon its exterior-and so constructed that it can contain such a quantity"
of liquid or semi-liquid as permits the application of a strong heat beneath its lowest.
side, which is covered with liquid or semi-liquid, while the remaining portion of
the inner side of the pan is covered only by the film of liquid, or semi-liquid,
which is carried up or along with it as the vessel revolves) with suitable heating
arrangements and with a fan or its equivalent so arranged as to cause a continuous
play of air upon the surface of the liquid or semi-liquid within the pan and upon
the surface of the film of liquid, or semi-liquid covering the inner side, all arranged
substantially as described and for the purposes set forth.
2. The combination of a rotating steam-jacketed concentrating or evaporating
pan (so constructed that it can contain such a quantity of liquid, or semi-liquid, as
permits its lowest side to be covered with liquid, or semi-liquid, while the remaining
portion of the inner side of the vessel is covered only by the film of liquid, or semi-
liquid, which is carried up or along with it as the vessel revolves) with a fan or its
equivalent so arranged as to cause a continuous play of air upon the surface of the
liquid, or semi-liquid, within the pan and the film of liquid, or semi-liquid, covering
its inner side, all arranged substantially as described, and for the purposes set
forth.
3. The combination with a rotating, concentrating, or evaporating pan-heated
either by fire direct or by steam-which is so arranged that one part of the pan is
covered with a depth of liquid and the other part with only a constantly changing
film, of a fan or its equivalent to cause a continuous play of air upon the surface of
the liquid, or semi-liquid, in the pan and of a scraper or scrapers to remove the film
from the inner surface of the pan substantially as and for the purposes described.
4. Apparatus for concentrating or evaporating liquids, or semi-liquids, with a
slightly conical pan rotating on an inclined axis constructed and arranged substantially
as and for the purpose described.
Dated this 10th day of November 1890.
WM. P. THOMPSON & Co.,
Manchester, Liverpool, and London, Patent Agents.