Improvements in the Method of and Apparatus for Concentrating and Evaporating Liquids, applicable also for Obtaining Solutions of Salts and the like.
Year: 1896

page_text: Date of Application, 7th Aug., 1896-Accepted, 3'st Oct., 1896
COMPLETE SPECIFICATION.
Improvements in the Method of and Apparatus for Concentrating
and Evaporating Liquids, applicable also for Obtaining Solutions
of Salts and the like.
.
We, ALEXANDER KUMPFMILLER, of Höcklingsen near Hemer, in the Province
of Westphalia, German Empire, Manager, and ERNST SCHULTGEN, of Iserlohn,
Hagenerstrasse 63, in the Province of Westphalia, German Empire, Engineer, do
hereby declare the nature of this our invention, and in what manner the same is
to be performed, to be particularly described and ascertained in and by the following
statement:--
This invention relates in the first point to the evaporation and concentration of
solutions of salts, in the second point to the production of such solutions, and in
the third to the interception of the separated crystals of the salts. In carrying
our invention into practice we make use of a vessel or reservoir containing the
solution or liquor to be concentrated or evaporated, and called hereinafter the
evaporator; and we make, further, use of a heating-device arranged in a certain
distance below said evaporator, and connected with the same by pipes. The heating-
device is called hereinafter the heater.
The heater as well as the pipes connecting the same with the evaporator are constantly
filled with the solution or liquor, and the latter is caused to circulate through the
heater, and consequently also through the evaporator, by the heater being supplied with
steam, or being heated by any other suitable medium. The solution or liquor
present within the heater is constantly under the pressure of the columns of
liquid present within the said pipes, and an important feature of our apparatus
resides in said pipes having such a length or height, that the pressure of the liquor
contained within the same hinders any formation of steam out of the liquor contained
within the heater.
The liquor contained within the heater is heated by the steam, or other heating
medium, but it is hindered from boiling or seething by reason of the pressure
exerted upon it by means of the columns of liquid contained within the pipes.
One of the latter serves, of course, for leading the (cooled) liquor from the
evaporator to the heater and the other pipe serves, of course, for leading the
(heated) liquor from the heater to the evaporator. The formation of steam
commences only in said second pipe, after the pressure of the column of liquid
of said pipe has got reduced in a certain measure. The formation of steam increases
in accordance with the decrease of said pressure, and there results, finally, a
mixture of liquor and steam that separates into its two components on entering the
evaporator mentioned.
The steam is then sucked off from the evaporator, and the latter is thus put
under vacuum, or is constantly kept in such a condition. Therefore, all the heat
taken up by the liquor within the heater is used up for the formation of steam
as soon as the heated liquor enters the evaporator. The liquor remaining from
said mixture of liquor and steam assumes a temperature corresponding to the
vacuum, or, more precisely, to the degree of rarefaction existing within said
evaporator.
There is thus a constant transmission of heat from the heater to the evapo-
rator, and a constant transformation of water into steam within the latter, or a
constant consumption of said heat for the formation of said steam respectively.
If the crystals of salt separated within the evaporator, or out of the solution or
liquor of the same respectively, are to be intercepted, we insert a suitable device

page_text: into the pipe leading the liquor from the evaporator to the heater; and, if a
salt is to be dissolved, or if ashes and the like are to be lixiviated, we insert a
similar device into the pipe leading the liquor from the heater to the said
evaporator, as is all fully described hereinafter.
In order to make our invention more clear, we refer to the accompanying
drawings, in which similar letters denote similar parts throughout the different
views, and in which :-
Fig. 1 is a diagrammatical view of the apparatus constructed by us for carrying
our improved method into practice; the apparatus is shown in vertical section and
certain portions of the pipes C and E are removed in order to reduce the height of
the figure;
Fig. 2 is a vertical section through a vessel intended to be intercalated between.
the two portions of the pipe C, Fig. 1;
Fig. 3 is a view similar to Fig. 1, but showing a modified form of construction,
and being drawn on a smaller scale.
Referring to Fig. 1 A is the evaporator, D the heater, and CE are the pipes
connecting the heater with said evaporator. In the form of construction shown,
the heater is formed by an upright serpent-pipe arranged within a suitable
vessel B, but we wish it to be understood that we do not confine ourselves to this
exact mode of construction. It will be clear to every expert that the construction
of the heater may be modified in a great variety of manners. The vessel containing
the serpent-pipe is constantly passed through by steam, and the solution or liquor
contained within said serpent-pipe, as well as within the pipe E, the evaporator A,
and the pipe C, is thus caused to circulate, as has already been described in the
preamble. The level of the liquor within the evaporator A may be ascertained by
the gauge-glass G, and said level is kept on a certain constant height by introducing
through the pipe F into the pipe C as much fresh liquor as corresponds to the
quantity of liquor removed in the form of steam out of the evaporator A.
If the concentrated liquor contained within the evaporator has been concentrated
or cooled down, in such a degree that there separate cystals of salt out of the same,
we remove said crystals by intercepting them on the concentrated liquor flowing
from the evaporator to the heater. For that purpose we insert into the pipe Ca
vessel H (Fig. 2) which is furnished with a perforated bottom or sieve J. Said
vessel is situated above the termination of the pipe F. The vessel H may be closed
or open, just as desired.
A vessel of similar kind may be employed if salts are to be dissolved, or if ashes
or the like are to be lixiviated. We have shown such an arrangement in Fig. 3
in which N is the vessel in question. Said vessel is intercalated between the
beater D and the pipe E, and it may also be closed or open, just as desired.
We are thus enabled to employ our apparatus not only for concentrating and
evaporating solutions of salts, but also for producing such solutions, and we may,
further, intercept the crystals that separate out of the said solutions. This
separation is due not only to the concentration of the solution, but to the reduction
of temperature, too, which the solution undergoes on returning to, or flowing back
into, the evaporator A.
The vessels H and N, Figs. 2 and 3, should be arranged at least so far below the
evaporator A that the columns of liquid contained within the pipes C and E are
held in equilibrium by means of the pressure of the outer air, provided, the
vessels Hand N be upen. If the latter are in a higher position, there cannot be
a proper circulation, but if their position is lower the proper circulation will not
be hindered. The liquor flowing into the vessel N from below is pressed into
the pipe E by means of the outer atmosphere; the vessel N is filled, of course,
up to the lower end of said pipe E, and is kept filled up to that height by a
suitable regulation of the flow of the liquor through the pipes C and M. The
pipe M proceeds from a condenser L, and terminates into the piece of pipe
connecting the vessel H with the heater D. The apparatus L serves for condensing
the steam entering, or being formed or freed within, the evaporator 'A, and passing

page_text: over from the latter to said apparatus L. The water of condensation flowing off
through the pipe M is employed for the dilution of the liquor flowing through the
pipe C into and through the heater, or for making said liquor apt for a further
dissolution of salts or lixiviation of ashes and the like respectively.
We wish it to be understood that we do not restrict ourselves to letting the
solution or liquor circulate through one and the same heater and one and the same
evaporator, but we may make use of any desired number of such apparatus,
and may cause the liquor after it has passed through one apparatus to flow over
into, and pass through, the next following one, and so on, until the degree of
construction desired has been obtained.
Having now particularly described and ascertained the nature of our said inven-
tion, and in what manner the same is to be performed, we declare that what we,
claim is :-
1. The method of concentrating a solution of a salt or salts, consisting in causing
the liquor to circulate from a higher level to a lower one, and back on another way
from the lower level to the higher one, by heating the liquor whilst being in the
lower part of its way; putting the liquor under pressure whilst flowing through
said part, and relieving it from the pressure whilst flowing through the upper part
of its way; the said pressure being as high as to hinder the liquor from boiling,
for the purpose as described.
2. The method of concentrating a solution of a salt or salts, consisting in causing
the liquor to circulate from a higher level to a lower one, and back on another way
from the lower level to the higher one, by heating the liquor whilst being in the
lower part of its way; putting the liquor under pressure whilst flowing through
said part, and relieving it from the pressure whilst flowing through the upper part
of its way; the said pressure being as high as to hinder the liquor from boiling,
and being formed by the column or columns of liquor present between the lower
level and the higher one, for the purpose as described.
3. The method of concentrating a solution of a salt or salts, consisting in causing
the liquor to circulate from a higher level to a lower one, and back on another way
from the lower level to the higher one, by heating the liquor whilst being in the
lower part of its way; putting the liquor, whilst flowing through said part, under
the pressure of the column or columns of liquor present between the lower level
and the higher one; and relieving the liquor from the pressure, whilst flowing
through the upper part of its way, by putting it under a vacuum, and sucking off
the steam resulting from said heating; the said pressure being as high as to hinder
the liquor from boiling, for the purpose as described.
4. The method of concentrating a solution of a salt or salts, consisting in causing
the liquor to circulate from a higher level to a lower one, and back on another way
from the lower level to the higher one, by heating the liquor whilst being in the
lower part of its way, putting the liquor, whilst flowing through said part,
under the pressure of the column or columns of liquor present between the lower
level and the higher one; and relieving the liquor from the pressure, whilst
flowing through the upper part of its way, by putting it under a vacuum, and
sucking off the steam resulting from said heating, and adding fresh liquor in
a quantity corresponding to said steam, the said pressure being as high as to hinder
the liquor from boiling, for the purpose as described.
5. The method of concentrating a solution of a salt or salts, and intercepting the
crystals separated out of the concentrated solution, consisting in causing the liquor
to circulate from a higher level to a lower one, and back on another way from the
lower level to the higher cne, by heating the liquor whilst being in the lower part
of its way; putting the liquor under pressure whilst flowing through said part, and
relieving it from the pressure whilst flowing through the upper part of its way, and
separating the crystals from the concentrated liquor by intercepting them whilst
said liquor flows from the higher level to the lower one; said pressure being
as high as to hinder the liquor from boiling, for the purpose as described.

page_text: 6. The method of dissolving a salt or salts, and concentrating the solution
so gained, consisting in causing the liquor to circulate from a higher level to a
lower one, and back on another way from the lower level to the higher one,
by heating the liquor whilst being in the lower part of its way; putting the liquor
under pressure whilst flowing through said part; relieving it from the pressure
whilst flowing through the upper part of its way, and letting the salt or salts to be
dissolved by acted one by the liquor on its way from the lower level to the higher
one; the said pressure being as high as to hinder the liquor from boiling, for the
purpose as described.
7. In an apparatus for concentrating a solution of a salt or salts, the combination
with a heater for the liquor, of an evaporator communicating by two pipes with the
hollow body of said heater; said evaporator being situated above the said heater
and having a pipe for sucking off the steam; the pipe connecting the lower end of
the evaporator with the lower end of the heater having a branch pipe for the
introduction of fresh liquor, for the purpose as described.
8. In an apparatus for concentrating a solution of a salt or salts, the combination
with a heater for the liquor, of an evaporator connected by two pipes with the
hollow body of said heater; the pipe connecting the lower end of said evaporator
with the lower end of the heater having a vessel furnished with a sieve, and having
a branch-pipe terminating into it below said second vessel, for the purpose as
.described.
9. In an apparatus for concentrating a solution of a salt or salts; the combination
with a heater for the liquor, of an evaporator connected by two pipes with said
heater; the pipe connecting the upper end of the hollow body of the latter with
said evaporator having a vessel furnished with a perforated bottom, for the purpose
as described.
10. In an apparatus for concentrating a solution of a salt or salts; the combination
with a reservoir containing said solution, and with a heating device for the latter,
of two pipes connecting the two ends of the hollow body of said heating device
with said reservoir; the steam-space of the latter being connected with a condenser
having a pipe adapted to lead the water of condensation into said hollow body; one
of, or both, the pipes connecting the latter with the said reservoir having a vessel
furnished with a perforated bottom or sieve, for the purpose as described.
Dated this 7th day of August 1896.
ALEXANDER KUMPFMILLER,
ERNST SCHULTGEN,
By Geo. H. Rayner.