Improvements in Processes and Apparatus for Evaporating Brine.
Year: 1899

page_text: Date of Application, 12th June, 1899-Accepted, 5th May, 1900
COMPLETE SPECIFICATION.
Improvements in Processes and Apparatus for Evaporating Brine.
I, REGINALD HADDAN, of 18, Buckingham Street, Strand, W.C., London, Patent
Agent, do hereby declare the nature of this invention, a communication to me
from abroad from Emilio Gorgo, of Rome, in the Kingdom of Italy, Chief of
the Division of Ministry of Finances at Rome, and Engineer, 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 to an improved process and apparatus for evaporating
brine.
Cooking or kitchen salt is generally produced by heat, either by the evaporation
only or by the ebullition of the salt solution contained in large open vessels or
in producing the concentration of the solution by evaporation in closed vessels at
a pressure inferior to that of the atmosphere. By means of the apparatus herein
after described, the following results are obtained, viz:-
1. Extraction of all the salt contained in a solution of normal density (from
18° to 20° Beaumé) or from a solution of less density, rendered of industrial
utility by reason of being concentrated by the apparatus itself, by means of an
apparatus for continuous production, causing the immediate total or partial
evaporation of the water which holds the salt in solution.
2. Utilization, with the smallest possible loss, of all the heat furnished by the
combustible burnt in the apparatus.
3. Production of salt either in the form of powder or in blocks; in the latter
case utilising the humidity, held by the salt when just produced by the apparatus,
in order to give it the desired form under the action of a suitable press and
also utilizing the heat which it retains and which is sufficient to dry the said
block of salt.
The annexed drawings illustrate the apparatus.
Fig. I shows a general sectional view of the apparatus.
Fig. II shows details of the distributing channel.
Fig. 1 shows a longitudinal section of the cylindrical heater taken on the
line A B C D E F G¹ of Fig. I and also on line II' I' M' of the same fig.
Fig. 1 a detail of the cover of the revolving cylinder.
Fig. I an elevation partly in section of the heater.
Fig. I and III details of the covering for the cylindrical heater.
Fig. 1b a side view of the heater.
Figs. II and III show details.
Fig. IV represents the apparatus as a whole and to make same clearer the
different parts have been designated by the same reference letters they bear in
the other figures. The dotted lines indicate the sections represented in the
other figures.
Fig. Villustrates a part of Fig. I on a larger scale.

page_text: From a suitable tank (not shown in the drawings) the salt solution or brine
to be evaporated on the surface of the revolving cylinder bereinafter described,
is conducted into the open vessel F where it is brought to a temperature of
about 35° C. by the effect of the heat given off by the mixture of the water vapour
and air which is conducted by the chimney hood E to the condensing pipes F
which traverse the said vessel F. On leaving the latter the mixture of air and
vapour not condensed passes into the chimney L.
From the vessel the salt solution passes by means of a pipe 12, provided
with a cock, into the closed vessel G as shown more particularly in Fig. 1. In
this latter vessel the temperature is increased and maintained at about 95° C.
by means of the heat given off by the heated gases from the fires, which gases
pass through the passages C surrounding the vessel G, into the chimney H and
from there escape into the atmosphere. The brine is thus previously heated,
and it is also purified thereby, because at 95° of temperature, the dissolved
sulphate of calcium, is almost completely separated.
From the said vessel G the brine passes into a distributing channel R of
marble or the like (shown in detail in Fig. II, Sheet 1, and Fig. V, (Sheet 5)
by means of another pipe, said distributing channel R being arranged along the
whole length of the revolving cylinder 6 of the heater hereinafter mentioned.
The channel R is filled by a pipe G¹ controlled by cock G³. In the brine con-
tained in this channel a sheet of amianthus or asbestos fabric R¹ is immersed
(Fig. V) which bears along its whole length on the edge of the distributing
channel R which is suitably formed for this purpose, the said edge being
perfectly horizontal. The said sheet adheres to the revolving cylinder at its
other end.
As soon as the liquid has arrived at a certain level in the channel R across the
said amianthus or asbestos fabric and along the whole length of the same a flow
of brine is produced on revolution of the cylinder, which quits the cloth R¹ at
its point of contact with the said revolving cylinder of the heater. The depth or
volume of the brine is exactly proportional, in a period of time, to the quantity
of brine which is poured into the distributing channel R during the same or a
corresponding period of time.
The heater is composed of two parts; an inner stationary part and an outer
revolving part which constitutes the covering for the said stationary part.
The inner part is closed at each of its two extremities by two plates S prefer-
ably of cast iron, each filled inside with a heat resisting material. Midway
between the two plates is placed a diaphragm S¹.
The grates of the heater, the double irons A¹ supporting the grates, the
plates which constitute the frame of the stationary parts of the heater and
divide its inner part between the two fire grates A, the ash pits and the
channels or flues Band (" for the products of combustion (Sheet 1 Fig. 1 and
Sheet 2, Fig. 1) and the before mentioned diaphragm S are all supported by
the cast iron plates S.
The part B represents an empty space between the metal plates constituting
the frame of the interior, stationary furnace. Through this empty space a
current of air can be caused to pass.
The revolving part of the heater which serves as a cover or casing for the
stationary parts consists of a cylinder & formed of three strong hoops m prefer-
ably of cast iron as shown in section in Fig. Ia Sheet 2, one at each end, and
one in the centre, all connected together by means of angle irons n running the
whole length of the cylinder (Figs. I and III).
The outer cover or jacket of the revolving cylinder may be made of bricks,
glazed on the outsde. For practical purposes however, it is preferable to make
it of a suitable number of preferably cast iron plates s enamelled on the outside
and curved to correspond with the shape of the cylinder. These plates are fixed
to the hoops m in such a manner that they are not prevented from expanding with
the heat.

page_text: The revolving part of the heater formed by the cylinder constructed as des-
cribed is supported by six or other suitable number of rollers f (Figs. I I* I* I°)
three being mounted on an axle or shaft u (Fig. I) the two end ones being fixed
and the centre one loosely mounted on said shaft, and three being all loosely
mounted on a second axle or shaft (Fig. 1).
The shafts u and rare preferably of steel.
The cylinder in question revolves round its axis and consequently round the
stationary parts of the heater by friction on the before described rollers f. The
shaft u operated through suitable toothed wheel gearing by the pulley M (Sheets 2
3 and 4, which is connected with the pulley of the motor, not shown) operates the
two end rollers f fixed on the shaft u and these rollers revolve the cylinder of the
heater by friction. As parts of the jacket of the said cylinder come adjacent to
the fire grate, they are heated and on continued movement the accumulated warmth
increases until there is on the outer surface of the cylinder a heat of about 130° C.
sufficient to cause the rapid evaporation of the water contained in the brine which
at this moment is caused to fall from channel R on to the cylinder by means of
the amianthus or asbestos fabric being agitated and emptying part of the contents
of the said channel R on to the cover of the cylinder.
On the outer surface of the cylinder a layer of salt is consequently deposited
whose thickness is dependent on the depth or volume of the brine emptied thereon,
the rapidity of the rotation of the cylinder, and the quantity of combustible
burnt in the furnace during the same period of time.
The salt which remains adhering to the exterior surface of the revolving cylinder
is carried with it in its movement and as it receives in addition to the heat
which it retains accumulated by the earthenware or cast iron plates, also the
heat of the hot gases escaping from the heater through the channel or flue B
(Sheet 1 Fig. 1) it dries until it reaches the row of knives d (Sheet 1 Fig. I,
Sheet 3 Fig. II and Sheet 4 Fig. Iº). The blades of the knives, maintained
constantly in contact with the outside surface of the revolving cylinder by means
of a double system of springs d and d³ (see section a b of Fig. IIb, Sheet 3)
loosen the incrustation of the salt and cause it to fall into a longitudinal
chamber N below the cylinder from whence the wormed shaft N¹ (Sheets 1 and 2,
Figs. I and I³) the worm of which is of aluminium or any other suitable
substance, conveys it into the pit Q (Sheet 2 Fig. I. In order to keep the
blades d' of the knives in constant contact with the exterior surface of the re-
volving cylinder, without, however, preventing small displacements, the blades d'
of the knives are forced against the cylinder by means of a powerful helical
spring de enclosed in the sheath The said sheath d is likewise pressed
towards the exterior surface of the cylinder by a steel bar operated by a spring
enclosed within the sheath . The tension of this latter spring may be adjusted
by means of a handle d³ shown in the drawing. The salt is lifted from the
chamber Q by means of a continuous moving chain of buckets or the like P
and transported into a suitable chamber and from there poured into a charging
hopper arranged above any suitable press.
After the knives d have operated, a circular brush e which is given a very rapid
rotary motion (Sheet 1 Fig. I) comes into action, which finishes the cleaning of
the outer surface of the cylinder. The entire heater between the two end plates S,
the channel R for distributing the brine and the longitudinal chamber N for
collecting the salt are encased in wood or other suitable material which
casing is arranged close to the revolving cylinder and ends at the top in
a hood E which has the purpose as before mentioned of conducting the mixture
of air and vapour coming from the surface of the cylinder, into the condensing
pipes F which pass through the open vessel F.
A grating or the like D (Sheet 1 Fig. 1) regulates the inlet and circulation
of the air for forwarding the vapours, the draught being produced partly by the
condensation of the vapours themselves in the before mentioned pipes F1 and
partly by the action of the chimney shaft L.

page_text: Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed, I declare that what
I claim is
1. An improved process of evaporating brine for producing salt in dry condition
by the rapid evaporation of a thin layer of brine previously purified and heated
and then re-heated to nearly boiling point.
2. In an apparatus for the improved process described in Claim 1 the arrange-
ment of a cylinder, the surface of which is constructed of a material capable of
accumulating a quantity of heat sufficient for the rapid continued and complete
evaporation of the brine, in combination with a row of knives which detach the
salt incrustation formed on the surface of the said cylinder substantially as
described.
3. In an apparatus for the improved process described in Claim 1 the arrange-
ment of a heater enclosed by a revolving cylinder a part of which is directly and
successively exposed to the action of the heating source contained therein which
utilizes the residue of the heat of the combustion products before the same can
escape into the chimney, in combination with a vessel for the re-heating which
utilizes the latent heat of the vapours which are produced on the surface of the
said revolving cylinder.
4. The improved process and apparatus substantially as herein described and
illustrated in the accompanying drawings.