Improvements in Apparatus for Evaporating or Distilling Liquids.
Year: 1895

page_text: Date of Application, 6th Aug., 1895
Complete Specification Left, 6th May, 1896-Accepted, 6th June, 1896
PROVISIONAL SPECIFICATION.
Improvements in Apparatus for Evaporating or Distilling Liquids.
I, EDUARD THEISEN, of 15 Werder Strasse, Baden-Baden, in the Empire of
Germany, Engineer, do hereby declare the nature of this invention to be as
follows:-
My invention relates to apparatus for evaporating or distilling liquids in which
either a single revolving drum, heated externally, or several concentric revolving
drums, of which the outermost one is heated externally, is or are supplied on its or
their internal surfaces with a thin layer of the liquid to he evaporated or distilled,
such liquid being by preference subjected to centrifugal action by the more or less
rapid rotation of the drum or drums so as to be very uniformly distributed in a
thin layer over the whole surface thereof while at the same time it is made to flow
from the one end of the drum to the other. By this means a very uniform and
rapid evaporative action is obtained, and in the case where there are two or more
concentric drums, the great advantage is gained that while the liquid in the outer
drum is being evaporated by the external heat, the liquid flowing through the inner
drum has a cooling effect upon the vapours produced in the outer drum, so that
these are directly condensed on the outer surface of the inner drum and the
resulting condensed liquid is caught up by suitable means and led away, thus
avoiding the disadvantage arising in the mode of distilling substances, such as
petroleum, at present employed, whereby the vapours distilled from a comparatively
large body of petroleum, become to a large extent condensed by contact with cooler
portions of the liquid, and in becoming again mixed up with the main body, undergo
a chemical change resulting in a reduced output of the lighter and more valuable
constituents of the petroleum and an increased production of the heavier and less
valuable constituents.
The apparatus for carrying out the above described mode of operating can be
variously constructed. In the arrangement with the single drum, this has a hollow
trunnion at one end, through which passes firstly a pipe for introducing the liquid
into the drum at one end, where it is spread over the entire surface either by
centrifugal action or by allowing a body of the liquid to collect at the lowest part
of the drum, so that on revolving a thin film is carried round on the inner surface
of the drum, which film is evaporated by heat applied either by a fire or otherwise
to the outer surface thereof. The liquid is at the same time made to flow gradually
to the other end of the drum, where a trough shaped annular enlargement is formed,
into which the liquid that has traversed the drum flows, and whence it is taken by
one or more scoops on the end of pipes, that lead the liquid out of the drum; this
pipe is by preference connected to the before-mentioned supply pipe by cocks or
valves in such a manner, that the said liquid can either be led entirely away from
the apparatus or it can be led back through the supply pipe into the drum again,
to be again subjected to the evaporative action, and so on repeatedly until the
liquid has attained a certain degree of concentration.
The vapours produced are led off through a pipe to be either directly utilised or
to be further treated.
The said pipes passing through the hollow trunnion of the drum are supported by
a stationary disc held by a hollow stem passing through the hollow trunnions and
fixed to an external support the periphery of which disc dips into liquid held by
centrifugal force in a circular trough at the end of the drum, thus forming a
hydraulic joint that effectually closes the interior of the drum.

page_text: According to one modification of the arrangement of several concentric drums
I cause the liquid, after having been supplied by pipes to one end of each
drum and made to travel thence along the drum, to be conveyed back again
to the inlet end by means of revolving conveying worms communicating with
the before mentioned annular collecting troughs at the ends of the drums,
which worms dishcarge the liquid into other annular troughs at the inlet ends
of the drums, whence it is taken by scoop-pipes as before described. Round
the outer surfaces of the inner drums are fixed a series of trough-like receptacles
so arranged as to overlap each other slightly while leaving room between them for
the vapour to gain access to the outer surface of the drum. Thus the vapour
distilled off from the thin layer of liquid in the outer drum, in becoming condensed
by contact with the outer surface of the inner drum as before described, is thrown
thence by the centrifugal force of the revolving drum, into the trough-like
receptacles, whence it is conveyed through pipes or channels to the outside.
It will be seen that with this arrangement the liquid will be subjected to
evaporative action at a different temperature in each drum, so that a different
description of distillate can be produced in each, and it follows that a process of
fractional distillation can by this means be carried on by first introducing the liquid
into the innermost and coolest drum, where the lightest distillate is separated, the
same body of liquid being then made to pass consecutively through each of the other
drums, where gradually heavier distillates are separated.
In some cases, where it is not desired to subject the liquid to the direct
action of fire heat, the outer drum may be made to serve only as steam jacket, the
vapour of the liquid therein, after giving off its heat to the next inner drum and
becoming thereby condensed, being allowed to fall back into the liquid in the
outer drum, so that the before-mentioned troughs for catching the distillate are
dispensed with in the latter.
According to another modification of the multiple drum arrangement, the before-
described worms for conveying the liquid back to the inlet end of the drum are
dispensed with, and the liquid, after having travelled along the surface of the
drum is taken up by scoop-pipes from the annular collecting troughs and is led
away, or to the supply pipe of the next outer drum. The construction is otherwise
similar to that above described.
It will be seen that in the multiple drum constructions, each inner drum acts
simultaneously as a condenser of the vapours generated in the next outer drum, and
as an evaporator of the liquid contained on its own inner surface, so that my
improved apparatus besides being exceedingly effective is also of a most compact
and comparatively inexpensive construction, combining in itself the several separate
evaporating and condensing apparatus at present required for carrying on a process
of fractional distillation. In all the above described arrangements the drums may
either be cylindrical with horizontal or inclined axis or they may be of conical or
tapering form.
Dated this 6th day of August 1895.
ABEL & IMRAY,
Agents for Applicant.
COMPLETE SPECIFICATION.
Improvements in Apparatus for Evaporating or Distilling Liquids.
I, EDUARD THEISEN, of 15 Werder Strasse, Baden-Baden, in the Empire of
Germany, 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 :-
It is well known that the evaporation of liquids is effected the more rapidly,

page_text: the thinner is the layer of liquid subjected to heat transmitted through surfaces
over which it flows, and the greater is the extent of such heat transmitting
surfaces.
It is also known that the transmission of heat from the heating surface to the
liquid takes placé more effectually and rapidly if motion is imparted to the liquid
on the said surface.
My invention relates to the construction of apparatus for evaporating or
distilling liquids in which the above mentioned advantageous modes of action are
carried out and in which, according to one modification thereof, the further
advantage is attained that the vapours given off from the thin film of liquid is at
once condensed within the apparatus by contact with cooling surfaces and carried
away, instead of being partially condensed by the contact with cooler portions of
the liquid itself and consequently requiring to be evaporated over again, as is the
case with evaporating and distilling apparatus heretofore employed.
The invention consists mainly in the employment of one or more revolving
drums, the outer surface of which is subjected to the action of heat while on the
inner surface thereof the liquid is made to travel in a thin layer, produced either
by centrifugal action, or by causing a certain quantity of liquid to lie in the
lowermost part of the drum, so that as this revolves it carries round on its inner
surface a film of the liquid which is evaporated by the transmitted heat. The
arrangements shewn on the drawings is assumed to act in the first described
manner.
In the arrangement shewn in longitudinal section and cross section at Figures I
and 2, the drum a, which may either be cylindrical with horizontal or inclined axis
or slightly conical and either with a plain or a corrugated surface and is closed by
plates o o' at the ends, is supported at one end by an axis b with driving pulley,
and at the other end by a hollow axis c, centrally through which passes a piped to
the other end of the drum, where it has a radial branch e fiom which the liquid to
be evaporated is delivered on to the inner surface of the drum a, so that by the
rotation of the latter the said liquid is caused by the resulting centrifugal action
to be distributed in a uniform thin layer over its surface while at the same time it
is made to flow at any desired speed (regulated by the rate of supply through d, e)
along the drum to the left hand end. At this end the drum is formed with an
annular enlargement 1, into which the liquid flows from the other part of the drum,
and whence it is taken up by a scoop at the end of a stationary pipe h which
passes through the hollow axis c of the drum and is connected by a stop cock to
the pipe d, so that the liquid taken up by pipe can be either entirely passed back
through d into the drum again or it may be partly or wholly discharged through a
branch k, the pipe d being in that case supplied partly or wholly with fresh liquid
through a branch with stop cock i.
The drum is contained in a brickwork or other casing f heated by a fire gor
by other means such as by the hot combustion gases from a boiler furnace, and
having flues formed as shewn so as to surround the drum and leading to the
chimney at fl.
Thus the liquid being made to circulate through the drum as described while
this is rotated and heated externally in a very uniform manner by the fire, a rapid
and effective evaporation or distillation of the liquid will be effected, the saine
body of liquid being, if necessary, acted upon repeatedly as may be desired until
either all the more volatile constituents are distilled off, or until the residue has
attained a certain degree of concentration, when it is discharged through the
pipe and cock k as described. The cock k also serves to take samples of the
liquid from time to time for controlling the progress of the operation.
The annular enlargement of the drum is divided by a ring-shaped plate n into
two compartments, the inner one serving to receive the liquid from the drum as
described, while the outer one is supplied with a body of water or other suitable
liquid, which is retained therein by the centrifugal action. Into this liquid dips
the periphery of a stationary disc m which supports the pipes hd p and which

page_text: forms a hydraulic joint with the water in that effectually prevents the escape of
any of the vapours generated in the drum and avoids the necessity of ordinary
packing, which would cause loss of power by friction. The disc m is supported
by the central tubular projection m¹ the outer end of which is fixed to a suitable
support. The vapours generated are discharged through a pipe p leading from
the disc m, to any locality where they are either directly utilised or are condensed
or otherwise treated or rectified as the nature thereof may require.
It will be seen that this apparatus readily allows of a process of fractional
distillation of petroleum and other liquids of a compound nature being carried out,
the fire heat being for this purpose increased at certain stages of the process in the
well known manner.
As before stated, instead of producing the thin layer of liquid upon the inner
surface of the drum by centrifugal action, the rotation of the drum may be
effected at a slow speed, so that a body of the liquid will collect in the lowermost
part thereof, and the drum in rotating will consequently only carry round a thin
film thereof, which will be subjected to the evaporative action of the heated
surface, this arrangement being more particularly suitable for apparatus of smaller
dimensions.
Figures 3 to 10 shew constructions of the apparatus in which the vapour given
off by heating the liquid is directly condensed in the apparatus itself by contact
with cooled surfaces, as before mentioned.
For this purpose there are provided two or more concentric drums of which the
outer one is heated externally by any suitable means while the inner one has heat
abstracted from its inner surface, so that the vapour produced from the thin layer
of liquid in the outer drum is condensed by contact with the outer surface of the
inner drum, and the resulting condensed liquid is then caught up from this surface
and led away.
At the same time the heat set free by the condensation of the
vapour is transmitted through the second drum and effects the evaporation of the
thin layer of liquid on its inner surface.
The apparatus is thus made to act simultaneously as an evaporator and a
condenser, and by thus at once condensing the vapours as they rise from a thin
layer of liquid the before mentioned disadvantage is avoided which arises in the
distillation of liquids such as petroleum in bulk in the ordinary manner, and which
consists in that the vapours distilled become more or less condensed by contact
with cooler portions of the liquid, and fall back into the body of the latter,
whereby their chemical constitution undergoes a change, resulting in a loss more
particularly of the lighter and more valuable portions of the distillate and in an
increase in the quantity of the heavier and less valuable residual liquid.
Figure 3 shews a longitudinal section and Figures 4 and 5 transverse sections
respectively at X X and Y Y of one construction for carrying out this mode of
operating. Figures 6 to 8 shew details, and Figures 9 and 10 shew respectively a
longitudinal and cross section of another construction.
In the arrangement shewn at Figures 3 and 4 there are arranged three con-
centric drums a a¹ a² which may either be cylindrical with horizontal or inclined
axis, or conical, and either with a plain or a corrugated surface; the three drums
are connected together in any suitable manner so as all to revolve together and
the outer one a is supported by hollow trunnions c running in suitable bearings,
the one trunnion being provided with a tocthed ring q, with which gears a toothed
driving wheel.
Through the one hollow trunnion passes a fixed concentric group of tubes d d' d²,
each of which is divided by a horizontal partition into two separate channels as
shewn more clearly at Figure 6.
Through the lower channels of these tubes the liquid to be treated enteis branch
tubes e ele each leading downward into one of the drums, by the rotation of
which the liquid is consequently spread by centrifugal action in a thin layer over
the entire inner surface of the drum, and is at the same time made to travel
slowly from the one end of the drum to the other. At the right hand end, each

page_text: drum has an annular enlargement forming a circular gutter into which the
liquid flows from the drum and in which it is retained by the centrifugal action to
a level corresponding to that of the thin layer of liquid in the drum. At.
diametrically opposite points of each drum are arranged tubular channels containing
conveying worms 71, the channels and worms being fixed inside the drum a,.
while and are fixed outside the drums a¹ and a².
These worms communicate with the troughs s s¹³ shewn more clearly at
Figures 7 and 8 the worm r being provided with small scoops for this purpose, so-
that on the worms being rotated, they will convey the liquid in the troughs back.
to the other ends of the drums again. Such rotation of the worms is effected by
fixing on the ends of their axes small chain wheels u u'u² over which pass pitch
chains that also pass over larger wheels t¹ fixed on a stationary axis t³, so that
as the drums with the worms rotate round the fixed wheels t t t, the chains will
be made to impart rotary motion to the worms. The liquid thus conveyed back
to the inlet end of the drum there passes into similar trough-shaped enlarge-
ments www, which are however separated from the layer of liquid in the drums
by an inwardly projecting annular partition ¹³. Into these troughs to wo³ w
project the scoop-shaped ends of stationary pipes h h¹³ the other ends of which
are fixed to and communicate with the upper channels of the tubes d d' d², so that,
as the drums revolve, these pipes scoop up the liquid from the troughs and convey
it away through the said channels.
Thus it will be seen that by this arrangement separate bodies of liquid are
conveyed firstly by the pipes e into each drum, are then made to travel in thin
layers along each drum, where they are subjected to the action of heat as will be
presently explained, are then conveyed by the worms r back to the inlet end, and
are finally discharged separately through the pipes and channels d which convey.
them into separate receptacles.
On the outer surfaces of the two drums a¹ and a² are fixed a number of
longitudinal trough-shaped receptacles y¹ y² so formed, as shewn in Figure 4, as to
slightly overlap each other, while leaving spaces for the vapour to pass between
them. Each such trough communicates at one end by a branch pipe with a
circular pipe Z1 Z, from which branch pipes Z3 Z4 lead to external annular
troughs Z Z fixed on the outer end surface of the drums.
The action of the above described apparatus is as follows:-The drum a is
inclosed in a casing of brickwork or other material, having flues surrounding the
drum and leading to a chimney flue f', and supplied with heat at f₁ by means of
liquid, pulverulent, or other fuel in any suitable manner; the drum a as it revolves
will consequently be heated externally in a very uniform manner, and this heat
will be transmitted through the drum to the thin layer of liquid upon the same,
which will consequently be very rapidly evaporated.
The vapours thus formed pass through the interstices between the troughs y' and
come in contact with the outer surface of the drum a'; this drum being cooled by
the liquid introduced onto the inner surface thereof through pipe el, the said
vapours will be condensed thereon and will be thrown off by the centrifugal force
due to the drums rotation, and caught up by the troughs y' which, in overlapping
each other, prevent any of the liquid being thrown back into the layer of liquid
on the drum a.
The liquid is held in the troughs y' by the centrifugal action, and flows therefrom
through the branch pipes into the circular pipe Z' and thence through the branch
pipes Z³ to the annular trough 7, from which it is led off by a stationary scoop-
pipe Z. The beat liberated by the above described condensation of the vapours
is transmitted through the drum a¹ to the thin layer of liquid therein, which is
consequently evaporated thereby, and these vapours are condensed by contact
with the outer surface of the drum a², which is cooled by the thin layer of liquid
therein.
The condensed vapours are caught by the trough y' and the liquid is carried off
by the pipes Z Z to the trough Z whence it is removed by the scoop pipe Z' as

page_text: above described. The liquid introduced into the drum a must of course be of a
somewhat lower temperature than that introduced into a', and this must again have
a lower temperature than that introduced into a, for carrying out the said operation.
It will be seen that as by the above described means the evaporation in drum a¹
takes place at a lower temperature than in drum a, the apparatus is particularly
suited for carrying on fractional distillations, such as are required in many
manufactures such as for petroleum distillation, and that in this case the liquid
that has circulated through drum a' can then be made to circulate consecutively
through the drums a' and a, for distilling off different constituents therefrom.
It will be readily understood that a greater number of concentric drums can
be employed if liquids of correspondingly different temperature stages are
available.
In some cases it may be desirable that the liquid to be distilled or evaporated
shall not be subject to the direct heat of the fire heat; in that case the outer
drum may serve merely as a steam, or vapour jacket for transmitting the fire heat
indirectly to the second drum a' the troughs y¹ and pipes Z' &c. being in that case
dispensed with, and the steam or vapour that condenses on the outer surface of
drum a¹ is allowed to fall back into the layer of liquid in a.
As in the above described apparatus each inner drum plays the double part of
condenser of the vapours of the liquid produced in the preceding drum, and as
heater and evaporator of the liquid contained on its own inner surface, it will be
seen that the heat produced from the fuel will be utilised in the most economical
manner, while the process is rendered capable of very easy regulation, as the
quantity of the cooling liquid and the extent of the heating and cooling surfaces
can be so proportioned that no undesirable rise of temperature of the liquid can
take place.
In the arrangement shewn at Figures 9 and 10 the same mode of operating is
carried out, the only difference consisting in dispensing with the transporting
worms of the preceding arrangement, the liquid being at once removed from
the drums by scoop-pipes h h h after it has travelled once along the drum.
Also, in place of the annular pipes for receiving the condensed liquid from the.
troughs yy, open annular gutters Z Z are provided at the ends of the drums,
into which the liquid flows from the troughs and from which it is removed by scoop
pipes Z³ Z*.
The supply of the liquid to the drums is also somewhat different in this case, a
fixed tubular axis A being provided, on which the combined drums rotate and
through this axis are led the stationary pipes e e¹ e for supplying the liquid, and
the scoop pipes h for discharging the liquid, this being continuously supplied
to the drums by the pipes e e¹ e at the right hand end, and, after traversing the
drum in a thin layer, continuously withdrawn therefrom at the left hand end by
the pipes. The action of the apparatus is otherwise the same as previously
described and need therefore not be further referred to.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
1. Apparatus for evaporating or distilling liquids consisting of an externally
heated drum, supplied internally with liquid at one point, and provided with a scoop
or equivalent means for withdrawing such liquid at a point removed from the point
of supply, the said drum being rotated at such a speed as to cause the said liquid
to travel over its interior surface in a thin layer from the point of inlet to the point
of discharge, whence it is conveyed back through a conduit to the inlet in order
to enable the same body of liquid to be passed repeatedly through the drum
substantially as described.
2. Apparatus for evaporating or distilling liquids, consisting of a drum enclosed
in a casing through which hot combustion gases are made to circulate so as to heat
the drum externally, while this is supplied internally with liquid at one point and

page_text: is rotated at such a speed as to cause the said liquid to travel over its interior
surface in a thin layer from the point of inlet to a point of discharge, where it is
caught up by a scoop connected to a conduit which conveys it away from the
drum, substantially as described.
3. In apparatus for evaporating such as is referred to in the first and second
claims providing the drum with an annular or trough like enlargement at the
discharge end into which the scoop or other device of the discharge conduit dips,
substantially as described.
4. In apparatus for evaporating or distilling liquids, the combination of a closed
revolving drum a, incans for heating the same externally, a pipe d, e, for supplying
the liquid to one end of the inner surface of the drum, a pipe h. for scooping up
the liquid from an annular trough at the other end of the drum and a pipe p for
discharging the vapour generated, from the interior of the drum, substantially as
described with reference to Figures 1 and 2 of the drawings.
5. In apparatus for evaporating or distilling liquids such as is referred to in the
fourth claim, closing the inlet end of the drum by means of a disc m projecting
with its periphery into liquid maintained by centrifugal action in an annular
enlargement or trough of the drum, the said disc being supported by a tubular
extension m' substantially as described with reference to Figures 1 and 2 of the
drawings.
6. Apparatus for evaporating or distilling liquids wherein the liquid to be
evaporated is supplied in a thin layer on to the inner surface of an externally
heated drum, the vapour resulting from the evaporation being at once condensed
by coming in contact with the outer surface of an internally cooled inner drum,
and the condensed liquid being caught up by receptacles and led out of the drum
substantially as described.
7. Apparatus for evaporating or distilling liquids cousisting of two or more
concentric drums each of which is supplied internally with liquid, the outer drum
being heated by any suitable means for evaporating the liquid therein while the
inner drum or drums is or are made to act firstly as a condenser for the vapour
generated in the next outer drum, and secondly as evaporator for the liquid
contained in such inner drum or diums, substantially as described.
8. In apparatus for evaporating or distilling liquids, the combination of two or
more concentric revolving drums, means for heating the outer surface of the outer
drum, means for supplying liquid to the inner surfaces of all the drums so as to
travel in a thin layer over the said surfaces in order to be evaporated by the heat
transmitted through them, means for removing the residual liquid from one or more
of the said drums and means for collecting and carrying off the liquid resulting
from the condensation of the vapour generated in one drum upon the outer surface
of the next inner drum, substantially as described.
9. In apparatus for evaporating or distilling liquids such as is referred to in the
seventh claim, providing trough-like receptacles on the outside of the inner drum
or drums for catching the liquid resulting from the condensation of vapour on such
outer surface of the inner drum or drums, the said liquid being conveyed from the
said receptacles by means of pipes leading to the outside, substantially as
described.
10. The adaptation of evaporating or distilling liquids, such as is referred to in
the 6th, 7th and 8th claims, to the fractional distillation of liquids by first
supplying the liquid to the inner surface of an inner drum where the most volatile
constituent is evaporated therefrom by the heat set free by the condensation of the
vapour in the next outer drum, the residual liquid being then conveyed from the
inner to the outer drum, where a less volatile constituent is evaporated therefrom
by the greater heat transmitted through such drum, the liquid resulting from the
condensation of the vapours being caught and conveyed away separately from each
drum, substantially as described.
11. The modification of the apparatus for evaporating or distilling liquids
referred to in the 6th, 7th and 8th claims, wherein the outermost drum is made to

page_text: -serve merely as a steam or vapour jacket for heating the next inner drum containing
the liquid to be evaporated, in order to protect such liquid from the direct action
of fire heat, substantially as described.
12. Apparatus for evaporating or distilling liquids constructed and operating as
.herein described with reference to Figures 1 and 2 of the accompanying drawings.
13. Apparatus for evaporating or distilling liquids constructed and operating as
herein described with reference to Figures 3 to 8 of the drawings.
14. Apparatus for evaporating or distilling liquids constructed and operating as
herein described with reference to Figures 9 and 10 of the accompanying
.drawings.
1000
ABEL & IMRAY,
Agents for the Applicant.