IMPROVEMENTS IN THE MODE OF EVAPORATING SALINE SOLUTIONS, AND IN APPARATUS USED FOR THAT PURPOSE
Year: 1877

page_text: LETTERS PATENT to Paul Piccard; of the City of Lausanne, Canton de Vaud,
in Switzerland, Engineer, for the Invention of "IMPROVEMENTS IN THE MODE
OF EVAPORATING SALINE SOLUTIONS, AND IN APPARATUS USED FOR THAT
PURPOSE."
Sealed the 13th March 1877, and dated the 9th January 1877.
PROVISIONAL SPECIFICATION left by the said Paul Piccard at the Office
of the Commissioners of Patents on the 9th January 1877.
26
PAUL PICCARD, of the City of Lausanne, Canton de Vaud, in Switzerland,
Engineer. IMPROVEMENTS IN THE MODE OF EVAPORATING SALINE SOLUTIONS,
AND IN APPARATUS USED FOR THAT PURPOSE."
My Invention consists in evaporating saline solutions of any sort under con-
ditions such that the salts which separate from the liquid by evaporation can be
removed in a continuous manner, and without putting the interior of the apparatus
into communication with the atmosphère.
+
The apparatus is composed of a cylindrical boiler C surmounted by a dome D, in
which there is an outlet aperture F. In the bottom of the cylinder C there is an
outlet orifice E, at which is attached the vertical tube T, which at its lower
end dips into the wooden tub B. The tube T is furnished with two stop valves V
and V placed one over the other, and with a space S between them. In the interior
of the cylindrical boiler C there is a closed vessel A presenting a large surface area.
This vessel may be of any other form presenting a large surface in a small space.
The boiler C is furnished with an orifice G for the admission of the liquid to be
evaporated. The vessel A communicates with the exterior by means of two tubes
Tandt (see the section Y, Y,); one of the tubes T₁ is connected with the upper
part of the vessel A, the other t is connected with the lower part of the same vessel.
The valve V being closed, steam at a temperature above that of the liquid is admitted
by the pipe T into the vessel A. The vessel A being thus heated imparts heat to
the liquid to be evaporated. The vapour rising from the solution escapes by the
orifice F, whilst the water from the condensation of the steam contained in the
vessel A escapes by the tube t.

page_text: During the operation care is taken to maintain the level of the solution, so that
the vessel A shall be just covered by the liquid.
If the nature of the salt be such that during the evaporation it adheres to the
surface of the vessel A. I adopt the following means to detach it :-Instruments,
which I will call "scrapers," to which a slow movement is imparted pass continually
over the exterior surface of the vessel A. According to the form of this vessel A
the movement of the scrapers will be circular, rectilinear, or otherwise. .
According to the annexed Drawing the movement of the scrapers is circular.
A gear wheel M, mounted on the axis of the vessel A, carries bars U, which are
fixed at their lower end to the two lower scrapers R¹, R¹, which are in one piece.
Between each lenticular. body a scraper R works, and these are also fixed to the
bars U. The scraper has the form of a segment of a spiral, "see the section X, X."
The gear wheel M receives from the pinion N the pulley P, and the axis O a slow
rotary movement. By the movement of the scraping instruments R the salt is
made to fall into the circular gutter Q formed in the bottom of the boiler. The
lower ends of the bars U entering into the gutter Q move the salt round until it
reaches the opening E by which the salt falls into the tube T.
Whatever be the arrangement of the scrapers, or where they are dispensed with,
the salt finds its way into the tube T. To remove it therefrom without putting the
interior of the boiler into communication with the outer air it is only necessary, to
open alternately the two valves V and V₁, and the salt after having filled the space S
falls into the tub B. To prevent the entrance of air into the apparatus during the
working of the valves the tub B is filled once for all with the solution which is
being operated upon, so that the lower end of the tube T may never be uncovered.
The salt which falls into the tub B is removed with a rake.
By means of this apparatus all descriptions of salt can be extracted from their
solutions with great economy of fuel.
When there is a natural hydraulic force available the steam which escapes by
the aperture F is sucked forward by a pump which compresses it, and returns it to
the vessel A. In consequence of this compression the steam in the vessel A is at
a higher temperature than the solution contained in the boiler, and continuous
evaporation of the solution results without expenditure of fuel.
According to the temperatures and the pressures employed the liquid condensed
at the bottom of the vessel A escapes by the tube t either under the influence of
the interior pressure, if this be above the atmospheric pressure, or it is drawn out
by a pump if there be a partial vacuum within the apparatus.
When no natural motive power is available I combine a number of the boilers
into a series or battery. The first boiler receives into its vessel A the steam from
an ordinary steam generator, and the aperture F of each apparatus is connected
with the vessel A of the next boiler, except in the case of the last boiler of the
series where it communicates with a condenser. An ordinary air pump extracts con-
densed water, injection water, and air; it will generally be worked by a steam
engine, and the exhaust steam, together with a certain amount of boiler steam, will
be passed into the first vessel A. The extraction of the condensed water from the
several vessels A will be effected as in the former case.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Paul Piccard in the Great Seal Patent Office on the 7th July
1877.
PAUL PICCARD, of the City of Lausanne, Canton de Vaud, in Switzerland,
Engineer. " IMPROVEMENTS IN THE MODE OF EVAPORATING SALINE SOLUTIONS,
AND IN APPARATUS USED FOR THAT PURPOSE."
My Invention consists in evaporating saline solutions of any sort under con-
ditions such that the salts which separate from the liquid by evaporation can be

page_text: removed in a continuous manner, and without putting the interior of the apparatus
into communication with the atmosphere.
The apparatus is composed of a closed cylindrical boiler A, A; Figures 1 to 4,
within which there is a vessel B, B, called the condensor; this latter never contains
anything but vapour of water, and it, is plunged entirely into the midst of the
solution to be evaporated, which fills up to the level N, N, the space C, C, comprised
between the condensor and the cylindrical body A, A. The bottom of the boiler
carries a
vertical tube F, J, furnished with two valves H and H¹, which include
between them a free space or lock chamber G. The upper valve is usually open,
and the lower valve H is usually closed. When steam is introduced by the tube D
into the condenser B at a temperature above that of the solution the vessel B, B,
yields its heat to the liquid which surrounds it; this evaporates, and the steam
introduced into the condensor condenses. The water from condensation runs away
by the pipe M, whilst the vapour which is disengaged from the solution escapes by
the tube E.
The salt produced by the evaporation forms a crystalline precipitate, which in
part falls to the bottom of the tube A, A, and in part remains attached to the sideś
of the condensor. To detach it therefrom, rakes move with a slow rotary motion
in the midst of the liquid to be evaporated, and pass within a few millemetres of
the surface in contact with the saline solution. The salt after it has been detached
falls on to the bottom of the boiler, and there it is carried on by the rotary motion
of the cross piece g, g, until it falls by the opening F into the lock chamber G. To
remove it, it is necessary to first close the valve H, and afterwards to open the valve
H. During this second operation the salt falls into the space J, from whence it is
withdrawn by the tube K. The valves are then replaced in their first positions.
To prevent any admission of atmospheric air into the boiler during the working
of the valves all that is necessary is once for all to fill the tube K with saline
solution.
It follows from what has been said that the boiler is always closed, for the two
valves are never open at the same time. For the same reason the liquid contained
in the tube F, J, is not able either to descend or to rise during the working of
the valves.
The functions of the apparatus being thus described the details of its construction
shall now be given.
The cover of the boiler carries a dome, within which there is a hood which is
intended to prevent particles of the liquid being carried over by the vapour into
the tube E. The water thus retained passes back into the boiler by the tube a.
The boiler is furnished with a junction L for feeding it with the saline solution
with a level gauge communicating by the tubes b and b¹ with the interior of the
boiler, and also with a man-hole.
The condensor, in order that it may present an extended heating surface within
a small
compass, is formed of a series of lense-like sections of sheet metal placed
one over the other, and bolted together with sound joints. A strong bolt d, d,
which passes through all the sections at the centre or axis, fixes them to the
bottom of the boiler, and prevents them from being deformed by the pressure within.
The steam is introduced at the bottom of the boiler by the tube D, which opens
into the uppermost lense-like section. Each section is furnished with a horizontal
diaphragm, which allows the passage of the steam only around the periphery, so
that it is forced to pass over the entire surface or the condensor. The water from
condensation, which collects at the lower part of the condensor, runs off by the
tube M.
The rakes, which have been spoken of above, are fixed to a frame formed of an
upper cross piece f, f, a lower cross piece g, g, and two uprights e, e. The frame
is fixed upon the lower end of the axis l, which is held suspended in the abutment
bearing, and has a slow rotary movement communicated to it by means of a
driving belt and pulley and bevilled gear exterior to the boiler. Within the boiler
the frame is guided at the two cross pieces f, f, and 9, g.

page_text: The rakes, of which two only in place of eleven are represented for the sake of
simplicity in Figure 1, have the form of a spiral arc, so that the salt may be
drawn by their movement towards the circumference of the sections of the condensor.
The rakes never touch the sections; the clearance of some millemetres, which is
left between the surface of the condensor and the rakes, is occupied by a crust of
salt adhering to the sections. This crust prevents accumulations from forming upon
the metallic surfaces, and prevents them from oxidation.
'
By means of this apparatus all descriptions of salt can be extracted from their
solutions with great economy of fuel.
When there is a natural hydraulic force available the apparatus can be applied
in a well-known manner, which consists in compressing the vapour resulting from
the evaporation to raise its temperature.
The steam which forms in the boiler A
is sucked forward by a pump, which forces it into the condensor B. In consequence
of this compression the steam is at a higher temperature than the solution contained
in the boiler, and continuous evaporation of the solution results without expenditure
of fuel.
The arrangement of the apparatus as described, and particularly the two valves,
permit the continuous extraction of the salt produced without disturbing or inter-
rupting the progress of the evaporation.
The water from condensation in the vessel B will have a temperature of from
100 to 120 degrees, and it escapes from the condensor by the tube M, but before it
is thrown away it is made to pass through the serpentine S, where it yields its heat
to the saline solution intended to feed the boiler. The serpentine S permits of the
' water from condensation being completely cooled, so that it will escape in a cold
state from the apparatus to which all the specific heat of the water is thus
restored.
When no natural motive power is available another well-known principle is
applied, long employed in sugar refineries and distilleries. In this case I combine a
number of the boilers into a series or battery. The first boiler receives into its
condenser B the steam from an ordinary steam generator, and the aperture or con-
nection E of each apparatus is connected with the condensor B of the next boiler,
except in the case of the last boiler of the series, where it communicates with an
ordinary condensor. An ordinary air pump extracts condensed water, injection
water, and air; it will generally be worked by a steam engine, and the exhaust
steam, together with a certain amount of boiler stean, will be passed into the first
condensor B. The extraction of the condensed water from the several condensors B
will be effected as in the former case.
I desire to claim under the present Patent the combination of the apparatus
above described, which permits of the continuous evaporation 'of saline solutions
in a close boiler from which the salt produced can be removed without putting the
interior of the apparatus in communication with the atmosphere, and this by the
employment. for the removal of the salt of a tube provided with two valves, one
over the other, the said apparatus consisting in a closed boiler heated by steam at a
suitable pressure arranged interiorly in a manner to present an extended surface.
under conditions which permit the rapid evaporation of saline solutions, and the
easy removal of the salts precipitated by the evaporation, with the addition when
they are required of a system of scrapers, either rotary, reciprocating, or otherwise,
to so prevent the adhesion of the salts to the interior surfaces of the boiler; and
essentially for the extraction of the precipitated salts of a tube furnished with two
valves, one over the other, descending from a suitable part of the boiler, and dipping
into a bath of the solution under treatment, this tube and these valves being
arranged so as to permit of the extraction of the precipitated salts without putting
the interior of the apparatus into communication with the outer air. The whole
substantially as I have described it, but without confining myself to the exact details,
which may be varied according to circumstances. The construction of the valves,

page_text: one or both, may also be varied, or other instruments capable of performing the
same functions substituted.
In witness whereof, I, the said Paul Piccard, have hereunto set my hand
and seal, this Twenty-ninth day of June, in the year of our Lord One
thousand eight hundred and seventy-seven.
PAUL PICCARD. (L.S.)