Improvements in the Crystallization of Salts or Crystallizable Acids.
Year: 1889

page_text: Date of Application, 15th July, 1889
Complete Specification Left, 15th Apr., 1890--Accepted, 17th May, 1890
PROVISIONAL SPECIFICATION.
Improvements in the Crystallization of Salts or Crystallizable Acids.
We, RICHARD CHARLES GARTON and CHARLES HENRY GARTON both of
Southampton Wharf, Battersea in the County of Surrey, Brewers and WILLIAM
LAWRENCE of 22 St. Mary Axe in the City of London, Brewer's Engineer do
hereby declare the nature of this invention to be as follows:-
:-
In the concentration of solutions of salts (whether neutral or having an acid or an
alkaline reaction) or of crystallizable acids, in order to crystallize them it is found
that the conductive action of the heating surfaces of the apparatus generally
employed quickly becomes impeded owing to the formation or growth of crystals on
such surfaces. If the process of crystallization is unduly prolonged in the case of
some solutions they become chemically changed or decomposed. Crystals, however,
do not readily form or grow if the solution is in a state of great mobility or
disturbance; also rapidity in the concentration tends to prevent their growth upon
the heating surfaces.
Now our invention consists in a process whereby solutions which are already more
or less concentrated are caused to flow in thin films down vertical or nearly vertical tubes
either internally or externally, the steam or medium for heating them by conduction
being on the reverse side, and are then received in a suitable vessel, and left therein in
a state of rest. The effect is that the solution in flowing down the tubes becomes
rapidly concentrated, any small crystals that may form on the tubes being capable of
easy removal, and that when the concentrated solution is left in a state of comparative
rest in the receiving vessel crystals rapidly form, from which the mother liquor
can be pumped intermittently or continuously so as to flow again down the same
or other tubes.
For the purpose of our invention we employ by preference an arrangement of one
or more or a set of tubes which are fluted, grooved or channelled either spirally,
longitudinally or laterally or are spirally twisted or are plain cylinders or truncated
cones having spiral metal pieces attached inside or outside, so as to give the solution
traversing the surfaces whether internally or externally a greater travel than if
passing down the walls of a plain cylinder or tube. The solution is exposed to the
atmosphere while being heated, that is to say, the apparatus does not work under
pressure or in vacuo.
When the solution flows externally the steam acts internally and the tubes are
closed at their ends and have suitable inlets and exits or connections for steam and
condensed water; the tops and bottoms of the tubes are fitted with feed supply
vessels and receiving vessels respectively. When on the other hand the solution
flows internally the ends of the tubes are left open and a feed supply is provided to
regulate the solution flowing over the heating surfaces, and a receiving vessel is
placed below. The tubes in this case are jacketted; the steam is admitted to the
jacket by an ordinary steam inlet and there is a condensed water exit.
Dated this 15th day of Jul., 1980
J. C. MEWBURN,
55 & 56, Chancery Lane, London, Patent Agent.
COMPLETE SPECIFICATION.
Improvements in the Crystallization of Salts or Crystallizable Acids.
We RICHARD CHARLES GARTON and CHARLES HENRY GARTON both of
Southampton Wharf, Battersea in the County of Surrey, Brewers and WILLIAM
LAWRENCE of 22 St. Mary Axe in the City of London, Brewer's Engineer, do
Price 8d T

page_text: 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:—
In the concentration of solutions of salts (whether neutral or having an acid or an
alkaline reaction) or of crystallizable acids in order to crystallize them, it is found
that the conductive action of the heating surfaces of the apparatus generally
employed quickly becomes impeded owing to the formation or growth of crystals on
such surfaces. If the process of crystallization is unduly prolonged in the case of
some solutions they become chemically changed or decomposed. Crystals, however,
do not readily form or grow if the solution is in a state of great mobility or
disturbance; also rapidity in the concentration tends to prevent their growth upon
the heating surfaces.
Now according to our invention we cause solutions which are already generally
more or less concentrated to flow in thin films down vertical or nearly vertical tubes
either internally or externally, the steam or medium for heating them by conduction
being on the reverse side, and to be then received in a suitable vessel and left
therein in a state of rest. The effect is that the solution in flowing down the tubes
becomes rapidly concentrated, any small crystals that may form on the tubes being
capable of easy removal, and that when the concentrated solution is left in a state
of comparative rest in the receiving vessel crystals rapidly form from which the
mother liquor can be pumped intermittently or continuously so as to flow again down
the same or other tubes. The crystals when necessary can be subsequently dried
by means of a centrifugal machine. The small crystals that may form on the tubes
can be removed by manual, or when necessary, mechanical means.
For the purpose of our invention we employ an arrangement of one or more or a
set of cylindrical or truncated cone-shaped tubes which are fluted, grooved or
channelled either spirally, longitudinally or laterally, or are spirally twisted, so as to
give the solution traversing the surfaces, whether internally or externally, a greater
travel than if passing down the walls of a plain cylinder or tube. The solution is
exposed to the atmosphere while being heated, that is to say the apparatus does not
work under pressure or in vacuo.
When the solution flows externally the steam acts internally and the tubes are
closed at their ends and have suitable inlets and exits or connections for steam and
condensed water; the tops and bottoms of the tubes are fitted with feed supply
vessels and receiving vessels respectively. When on the other hand the solution
flows internally the ends of the tubes are left open and a feed supply is provided to
regulate the solution flowing over the heating surfaces, and a receiving vessel is
placed below. The tubes in this case are jacketted; the steam is admitted to the
jacket by an ordinary steam inlet and there is a condensed water exit.
The tubes will be of metal, glass, earthenware, porcelain, or other material adapted
to the particular, solution to be treated.
.22
Figure 1 represents in elevation partly sectional an apparatus comprising a single
spirally twisted tube and suitable for carrying out our invention when the solution to
be treated flows externally. a is the spirally twisted tube which may be one of a set or
series; the solution is supplied by a regulating cock to a feed trough c from which
it flows in a film through the annular outlet d to the exterior of the tube; the
solution after flowing down the tube is received in the vessel e and may be conveyed
away gradually or intermittently by the pipe fto be pumped back into the trough c
or otherwise. The tube a is closed at both ends except for the inlet pipe g which
supplies the steam for heating the solution and the outlet pipe h which carries off the
condensation water. The solution in flowing down the tube a becomes rapidly
concentrated, and when it is left in a state of comparative rest in the vessel e crystals
rapidly form.
Figure 2 represents an apparatus suitable for carrying out our invention when the
solution flows inside a spirally twisted tube. The tube a is in this case left open at
the ends and has a steam jacket i. The solution to be treated is supplied by the
regulating cock to the feed trough c and gradually overflows the top of the tube a

page_text: 50 as to enter the same and flow down its inner wall in a film until it reaches the
receiving vessel e at bottom. The steam is admitted to the jacket by the pipe 9,
and the condensation water passes off at h.
When desired a doubie effect can be obtained by employing steam or heated gases
or direct fire to heat the tube internally, while the solution flows externally and by
jacketting the tube with another twisted tube down the outside of which the solution
also flows, the vapor generated on the outside of the inner tube forming the heating
medium for the outer tube. This will be understood on reference to Figure 3 in
which a is the inner twisted tube, b the regulating cock for the solution, c the feed
trough, d the annular outlet through which the solution passes in a film to the outside
of the tube, e the receiving vessel, g the steam inlet, the condensation water outlet,
k the outer tube, a feed trough supplied by the regulating cock m and having an
annular outlet n to allow the solution to flow in a film from this trough to the outside
of the tube and p a receiving vessel for the solution that reaches the bottom of this
tube.
The diameter and the particular kind of channelling or grooving of the tubes
can be varied as thought best according to the solution for which the apparatus is
required, and the special form of the apparatus. We have found that when the
solution is very viscous and liable to set up a bubbling action the spiral twists are best
made at an angle of about 45°, the indentations or channels being largest on the
outside surface of the tubes, like the grooves of a screw (see the cross section
Figure 1) and that when it is wished to retard the travel of the solution a slower
twist or one less than an angle of 45° is preferable. The diameter of the tube should be
chosen according to the general considerations.
We have found tubes of from one
and a half to about five inches to answer well for outside ovaporation. The same
observations are applicable as regards deciding upon the most advantageous tubes for
inside flow of the solution, but in this case the indentations or channels should be
largest on the inside surface (see the cross-section Figure 2). If the tubes are
to be heated internally by fire heat they should be of considerably larger diameter.
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:-
The crystallization of salts or crystallizable acids in the manner herein before
described, that is to say, by causing solutions of such salts or acids to flow in thin
films down the inside or outside of vertical or nearly vertical tubes which are fluted,
grooved or channelled either spirally, longitudinally or laterally, or are spirally
twisted, steam or other medium for heating the solutions being on the reverse side of
such tubes, and by receiving the solutions in a vessel after having flowed down the
tubes and leaving them in this vessel in a state of rest, whereby crystals rapidly form
in the said vessel, substantially as set forth.
Dated this 15th day of April 1890.
J. C. MEWBURN,
55 & 56, Chancery Lane, London, Patent Agent.