Improvements in Methods and Apparatus for the Continuous Concentration of Liquids.
Year: 1895

page_text: Date of Application, 8th Feb., 1895
Complete Specification Left, 7th Nov., 1895-Accepted, 28th Dec., 1895
PROVISIONAL SPECIFICATION.
Improvements in Methods and Apparatus for the Continuous
Concentration of Liquids.
I, SAMUEL MORRIS LILLIE, of 328 Chestnut Street, City and County of
Philadelphia, State of Pennsylvania, United States of America, Manufacturer, do
hereby declare the nature of this invention to be as follows:-
The invention relates to the continuous process of concentration in which the
solution in process of concentration has a practically continuous flow through the
evaporating apparatus, though not at a constant rate, the rate varying with
the rapidity with which the apparatus is working and with the amount of concer-
tration desired for the solution in process. The process consists in regulating the
rate of flow of the solution through the evaporating apparatus, and consequently
the density of the concentrated solution automatically, by means of the weight or
density of the solution leaving the apparatus, acting through suitable means to
increase the flow of solution through the apparatus and against an adjustable or
regulable force tending to diminish or stop the said flow. The preferred apparatus
consists of a valve in the solution supply or discharge pipe of the apparatus
connected with and operated by a movable or expansible diaphragm or piston, which
in turn has a pressure exerted upon it tending to move it to open the said valve by
a column of the solution which is maintained by suitable means at practically the
same density as that of the concentrated solution leaving the apparatus; and it
consists furthermore, of a counterpoise, adjustable as to its weight or leverage,
which tends to close the valve against the pressure of the said column of solution,
and as a rule it consists still further of means, in combination with the above, for
maintaining the quantity of solution in the apparatus practically uniform.
Assuming an ordinary evaporating pan for concentrating solutions by evaporation
in vacuo, the solution flows into the pan through a pipe regulated by a hand
controlled or automatically controlled valve to keep the solution at a certain height.
A pump draws the concentrated solution away from the evaporating pan by a
continuous or practically continuous operation. The discharge pipe from the pump
leads to a balanced poppet or piston valve, supported upon the roof of an air tight
chamber, and the stem of the valve extends downwards through the roof of the
chamber, and is attached below to a flexible diaphragm, which divides the chamber
horizontally into upper and lower compartments. The upward movement of the
stem opens the valve while the downward movement of the same closes the valve.
A pipe about one inch in diameter which leads from the lower compartment of the
chamber upwards for a certain distance and enters the upper part of the pan, is
connected by a small pipe with the discharge of the pump. The pump causes a
flow of part of the solution delivered by it up through this column pipe back into
the top of the pan, and thus maintains in the said pipe a column of solution always
at the density at which the concentrated solution is delivered from the pan by the
pump. This column of liquid exerts an upward pressure upon the diaphragm
tending to open the valve in the discharge pipe of the pump.
From the
compartment of the chamber above a small pipe extends upward and terminates in
an enlarged section which constitutes the water or counterpoise column and
continues upward to a height depending upon what is to be the maximum density
at which it is desired to have the solution flow away from the evaporating pan.
The top of this enlarged section is connected by a small pipe with the top of the

page_text: evaporating pan so that the same pressure may be maintained on the top of
the water column as exists above the solution column in the solution column pipe
which leads to the lower compartment of the chamber. A valved supply pipe for
water communicates with the enlarged section of the water column, and a drain pipe
leads from the same. By means of the valves in the water connection and drain pipe
the water column in the enlarged section may be filled to any height and the level may
be changed to any height desired. The water column acting through the upper
compartment of the valve controlling chamber against the diaphragm tends to
close the valve in the discharge pipe against the upward pressure of the column of
solution in the solution pipe which tends to open the valve. The enlargement for
the water column may be provided with a gauge glass to indicate the level of the
water therein which may be graduated to a scale indicating specific gravities. By
regulating the elevation of the water column in its chamber to correspond with
the desired specific gravity, the outlet valve will be so controlled as to maintain the
desired specific gravity in the outflowing liquor. The height of the water column
may be lowered by weighting the diaphragm in the chamber by weights or springs.
As a modification of the apparatus described, a separate pump for circulating the
solution through the liquor column, may be used. Again the diaphragm in the
chamber may be replaced by an expansible rubber bag, with the interior of which
the solution column communicates and which is expanded by the hydrostatic
pressure of the solution column to raise a plate bearing upon it, and in lieu of the
water column to counterpoise the solution column a weighted lever may be used
pressing upon the plate on the expansible bag. An adjustable weight acting on
the lever will regulate the pressure and consequently the density of the solution
which will operate the valve. The motion of the piston or diaphragm may be
utilized as another modification to vary the flow of the concentrated solution away
from the apparatus by varying the speed of the tail pump instead of by opening
and closing a valve in the discharge pipe. The top of the solution column and of
the water column, if used, may be open to the atmosphere; in which case the
overflow of the liquor from the top of the solution column is into an open tank
and may be led back to the pan; or, when the solution is at proper density, may
be sent into the same receptacle into which the concentrated solution flowing from
the discharge pipe is led.
In a further modification the solution column may have interposed in it a vessel
or chamber within which is arranged a movable arm pivoted to one end of the
chamber and having its free end connected to a float. This arm is also connected
with the stem of the discharge valve, so that the movements of the float up and
down operate the valve to open and close it. An adjustable counterpoise weight
on the arm may be adjusted by hand to exert a greater or less downward pressure
upon the float.
In this construction the float operates the valve by virtue of the
varying density of the solution, and, by adjusting the weight, the float may be
made to rise at a given density. In a further modification the solution column
may be a horizontal hollow pipe, closed at one end and oscillating on and supported
by two pivot bearings at the other end. Beyond the bearings extends a lever
provided with an adjustable counterpoise weight. The hollow pipe is connected
with the valve for controlling the outflow of the solution by suitable connections.
The variation in the density of the solution flowing through it will rock the
hollow pipe and thus operate the valve, and the density of the liquor, at which
the valve will be operated, will be regulated by the adjustment of the counterpoise
weight.
The density of the liquor may also be regulated by having the automatic
regulator control the flow of the dilute solution into the pan instead of the discharge
of the concentrated solution from the pan.
The improvements are adapted to evaporating apparatus of any character where
there is a discharge after the concentration of the liquid has reached such a stage
that a given density is secured. The improvements may be applied to multiple
effects as well as to single effects, and are also applicable to such apparatus as

page_text: extractors, or any apparatus in which solutions of substances are made, in which the
density of the resulting solution depends upon the rate at which the solution passes
through the apparatus. It is preferable to have the density in the solution
column maintained as nearly as possible the same as the density of the solution
leaving the apparatus. It may occur in cases when the solution is concentrated to
a high degree of viscosity, or for any other reason, that it will be desirable to have
the solution in the column maintained at a lower density, though still one which
will increase and diminish with the density of the solution leaving the apparatus.
This may be effected by maintaining, through a suitable connection, a small uniform
flow of water or of dilute solution in the bottom of the solution column.
Signed, at Philadelphia, this Twenty-fifth day of January 1895.
SAMUEL MORRIS LILLIE.
Haseltine, Lake & Co.,
45 Southampton Buildings, London, W.C., Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements in Methods and Apparatus for the Continuous
Concentration of Liquids.
1, SAMUEL MORRIS LILLIE, of 328 Chestnut Street, City and County of
Philadelphia, State of Pennsylvania, United States of America, Manufacturer, 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 :-
My invention relates more particularly to the continuous process of concen-
tration, i.e., in which the solution in process of concentration has a practically
continuous flow through the evaporating apparatus, though not at a constant rate,
the rate varying with the rapidity with which the apparatus is working, and with
the amount of concentration desired for the solution in process. My process
consists in regulating the rate of flow of the solution through the evaporating
apparatus, and consequently the density of the concentrated solution, automatically
by means of the weight or density of the solution leaving the apparatus, acting
through suitable means to increase the flow of solution through the apparatus, and
against an adjustable or regulable force tending to diminish or stop the said flow.
The apparatus which I prefer for practising this method, consists of a valve in
the solution supply, or solution discharge pipe of the apparatus, connected with and
operated by a movable or expansible diaphragm or piston, which in turn has a
pressure exerted upon it tending to move it to open the said valve by a column of
the solution which is maintained by suitable means at practically the same density
as that of the concentrated solution leaving the apparatus, and it consists further
of a counterpoise, adjustable as to its weight or leverage, which tends to close the
valve against the pressure of the said column of solution, and as a rule it consists
still further of means, in combination with the above, for maintaining the quantity
of the solution in the apparatus practically uniform.
In the accompanying drawings is shown apparatus adapted to practice my
invention, of which drawings
Figure 1. is a view of the apparatus I prefer, and Figures 2, 3, 4 and 5 show
modified apparatus adapted to practice my invention.
Referring to Fig. 1, E represents an ordinary type evaporating pan for concen-
trating solutions by evaporation in vacuo, in which the tubes are surrounded by
steam supplied through a main S, while the solution in process of concentration
fills the tubes, the space below the lower tube plate, and part of the vapor dome
above the upper tube plate. The dilute solution flows into the pan through the
pipes, as regulated by a hand valve v³, or by a valve v automatically controlled to

page_text: keep the solution at a certain height in the pan by the float f in the chamber F,
which chamber is connected from above and from below with the interior of the
pan so that the liquid always stands at the same level in the chamber and in the
pan. The float is connected with the valve e by intermediate mechanism which
acts to close the valve as the float rises with the level of the liquid, and to open it
as the float falls. This combination of devices, it is evident, operates to let fresh
solution into the pau as rapidly as it is evaporated, or is drawn away from the pan,
and so to keep the liquid in the pan at a nearly constant height and quantity.
B is a pump, commonly called the "tail pump," represented in the drawings as a
centrifugal pump, which draws the concentrated solution away continuously or
practically so from the bottom of the evaporating pan through the pipe 6 and
delivers it away through the pipe at a rate controlled by the valve V in the
pipe c. The valve V shown is a balanced poppet or piston valve, such as are
commonly sold in the market, and is supported upon the roof of the air tight
chamber C. The stem a of the valve V extends downward through the roof of
the chamber and is attached to the flexible diaphragm D which horizontally
divides the chamber C into an upper compartment d and a lower compartment e.
Movement of the stem a upwards opens the valve V, while movement of the same
downward closes the valve. G is the solution column pipe of about one
inch in diameter, which leads from the chamber e, below the diaphragm,
upwards for a certain distance and leads into the upper part of the pan.
Into the bottom of this solution column pipe a small pipe h, preferably
considerably smaller than the solution column pipe G, leads from the discharge
of the tail pump B, which pipe-when the tail pump B is running-causes
a flow of a part of the solution delivered by the pump B to flow up through
the column pipe G back into the top of the pan, and so maintains in the pipe G
a column of the solution always at the density at which the concentrated
solution is delivered from the pan by the pump B, which column exerts, pro-
portionate to its density, an upward pressure upon the diaphragm D tending to
open the valve V in the discharge pipe c of the tail pump B. From the chamber d
above the diaphragm D a small pipe extends upwards and terminates in an
enlarged section J, which, with the pipe i, is called the water or counterpoise
column, which continues upward to a height depending upon what is to be the
maximum density at which it will ever be desired to have the solution flow away
from the evaporating pan. The top of the pipe J is connected by the small pipe k
with the top of the pan E, by which means the same pressure is maintained in the
top of the water or counterpoise column as exists above the solution column G,
which also opens into the top of the pan. A supply pipe l, with valve, for water
opens into the water column at some convenient point, and a draining pipe m leads
from the same, conveniently into the pan E. By means of the valves in the water
connection and in the drain pipe m the column J may be filled to any height with
water, and the level of the latter changed to any height desired. The water
column J, varying with its height, exerts a downward pressure against the
diaphragm D and tends to close the valve V in the discharge pipe c of the pau,
against the pressure upwards of the column of solution in G, which tends to open
the said valve. The water column J is provided with a gauge glass
u which
indicates the level of the water in the column J, and which is graduated with a
scale indicating specific gravities, the graduations indicating the heights of the
water column which will respectively just balance the column of solution in the
pipe G when it has the densities indicated by the graduations of the scale. Thus,
if the level of the water in the column J stands at 1-2 on the scale, it will
just balance the column of solution in G when it has a density 1-2, and any
increase in the density in G would cause the valve to open, which would be closed
again by the water column at once if the density of the solution column in G
should fall below 1-2.
The operation of the above apparatus is as follows: Assuming that it is desired
to have the solution in process concentrated to and flow away from the pan at a

page_text: density of about 1.3, water is run into the column J from the pipe until the water
rises in J to the level marked 1.3. The pan E is charged with the dilute solution
to be concentrated by opening the hand valve in the supply pipe s, and allowing
the solution to flow into the pan as regulated by the float and the valve v. Steam
is turned into the space around the tubes through the main S, which causes the
solution to boil and the contained water to evaporate and pass out through the
vapor main H of the pan to the condenser, not shown, and the solution to gradually
increase in density. The centrifugal tail pump B maintains a flow of concentrated
solution via the pipe up through the column G, and also maintains a sufficient
pressure of solution in the discharge pipe e to flow away through the same against
atinospheric pressure when the valve V opens. The solution in the column G
being kept at the same density as that in the pan E, it exerts, as the concentration
in the pan progresses, an increasing pressure upon the diaphragm D tending to
open the valve V. When the density reaches 1-3-for which the water coluinn
has been set-the pressure exerted by the solution column upon the diaphragm
just equals that exerted by the water column, and when the density of the solution
becomes a trifle greater, the diaphragm is raised by the weight of the solution
column to open the valve V, and the concentrated solution flows away through the
pipe c. Should the deusity fall at all below 1-3, for which the water column has
been set, the water column would overbalance the solution column and the valve V
would be closed and stop the discharge of the solution from the pan. Thus, if the
pipe c, and valve V are large enough to take away, when the valve is wide open,
the solution more rapidly than the pan is able to concentrate it, it is apparent that
the density of the solution leaving the pan will vary from a little above 1-3 to a
little below 13 and will average about 13 in density. As material leaves the pan
us vapor through the main H, and as concentrated solution through the discharge
pipe c, it is replaced by dilute solution entering through the feed pipes, which is
automatically regulated by the float f, and the valve v, which the float actuates, so
that the level of the liquid, and consequently its quantity, is maintained practically
constant. The feed through the pipe's could be regulated by a hand valve v', but
this would make the apparatus only partially automatic, while with the feed auto-
matically controlled as well as the discharge, the apparatus is made quite automatic
as respects the flow of solution through the saine, and the density of the finished
product. By lowering the column of water by draining water away through the
pipe m, or by raising the column of water by running water into it through the
pipe the density at which the concentrated solution will flow away from the pan
may be lowered or raised respectively.
I would further state that when the diaphragm is raised by the liquor column
to open the valve V, water is driven from the upper compartment of the regulator
chamber into the water column, and thereby increases the height of the column
of water to a degree which will vary inversely with the cross section of the water
column J, and consequently to raise the diaphragm more and more, and so open
the valve V wider and wider, demands an increasing density in the column G, i.e.,
in the solution flowing away from the pan, and it therefore follows that if the
water column has not too large a cross-section the flow of concentrated solution
will not be intermittent, but will be constant, though varying in quantity if the
work of the pan is not constant. Thus, the solution will begin to flow away
slowly on reaching density 1-3 say, but not fast enough to keep down its density
which, as it continues to increase, will open the valve wider and wider, until the
solution flows away fast enough to keep the density from increasing, and then
the valve and flow will remain stationary until conditions vary to change the
deusity of the solution should the same rate of outflow continue, when the valve
would take a new and corresponding position and give a corresponding rate of
outflow. The density of the outflow would consequently vary slightly with the
rapidity with which the pan was working, which variation would be inversely as
the cross section of the water column.
The pressure above the water column and above the liquor column, are maintained

page_text: the same by connecting both with the interior of the pan E, so that the pressure
on the two sides of the diaphragm tending respectively to open and to close the
valve V are due solely to the solution column and to counterpoise column. If
the top of the liquor column were open to the atmosphere, as is in the case in the
arrangement shown in Figure 2, the water column would also be open to the
atmosphere.
The height of the water column may be lowered by weighting the diaphragm D,
as by the piece of metal w resting upon it, or by springs pressing against it.
For example, if the weight, or pressure of the springs downward, is equivalent
to a pressure of 2 lbs. per square inch upon the upper surface of the diaphragm,
the water column pipe i could be shortened 4 feet, and if a sufficient weight, or
strength of springs were employed, the graduated section J of the water column
could be brought down near the regulator. The height of the counterpoise column
could also be diminished by using in it a heavier liquid than water, mercury for
example.
In Figure 2 are shown other constructions of apparatus adapted to practice my
invention, which apparatus differs from that shown in Figure 1, 1st, in having a
pump N, separate from the tail pump B' for circulating the solution through the
column G'; 2nd, in having the top of the solution column G₁ open to the
atmosphere, 3rd in having the diaphragm D' replaced by an expansible rubber
bag with the interior of which the solution column communicates, and which is
expended to raise the plate p' and stem a' by the hydrostatic pressure of the
solution column; 4th, in substituting for the water column counterpoise a weighted
lever J', which presses down upon and resists the raising of the stem a' by the
solution column, the weight W' on which lever is adjustable as to its distance
from the fulcrum, so that the resistance against the solution column, and con-
sequently the density of the solution, may be increased or diminished by moving the
weight further from or nearer to the fulcrum; 5th, in having the motion of the
piston or diaphragm vary the flow of the concentrated solution away from
the apparatus by varying the speed of the tail pump B', instead of by opening
and closing a valve in the discharge pipe, thus the lever J is connected by the
rod n, with a throttle valve t in the steam supply pipe to the steam cylinder of
the pump B', which is shown as an ordinary steam piston pump, in such manner
that as the lever J' rises, it opens the throttle valve and starts or increases the
speed of the tail pump, and hence also the rate of discharge of the concentrated
solution, and if the lever falls the contrary effect is produced. In the arrange-
ment shown in Figure 2 the top of the liquor column is open to the atmosphere
and the counterpoise side of the diaphragm D' is also exposed to the atmosphere,
and consequently the differences of pressure between the two sides of the
diaphragm tending to move the same will be due entirely to the solution column
and to the counterpoise, or rather, to the fluctuations in the density of the
solution column, the counterpoise having been set for a definite density. The
overflow of liquor from the top of the solution column G is into an open tank T,
and may be trapped back into the pan or, when the solution is up to density, the
overflow may be sent into the same receptacle into which the concentrated solution
flowing from the discharge pipe c¹ is sent.
9
In Figure 3 I have shown substantially the same arrangement of the evaporating
pan and float controlled valve for controlling the supply of liquid to the pan as
illustrated in the previous figures. In this construction the solution column has
interposed in it a vessel or chamber C¹. Arranged within this vessel or chamber
is a movable arm D¹ pivoted to one end to the chamber or vessel and having its
free end connected to a float D². That arm D' is also connected with the valve
stem a of the discharge valve V so that the movements of the float * up and
down operates the valve V to open or close it. D' is an adjustable counterpoise
weight arranged upon the arm D' and may be adjusted by a hand rod D so as to
exert a greater or less downward pressure upon the float according as to whether
it is moved nearer or farther from the float. D' is a diaphragm which also acts as

page_text: a guide for the float D2 and is arranged at the lower part of the vessel C¹. In this
manner the circulating liquid does not by its force of circulation strike the float
and cause it to rise, but on the other hand the float acts to operate the valve by
virtue of the varying density of the solution. The greater the density the greater
the tendency of the float to rise. By adjusting the weight D³ the float may be
made to rise at a given density and thus cause the discharge valve to open only
when that density is reached.
In Figures 4 and 5 is shown other apparatus adapted to practice my invention,.
in which the solution column G2'is shown horizontal. The column is closed at one
end and the other end is supported by and oscillates on two pivot bearings and 2.
Beyond the bearings on the other side from the solution column extends a lever J2
on which hangs a counterpoise weight W2 which is adjustable as to its distance
from the pivot bearings. The oscillations of the solution column are transmitted
by an arm n attached to the solution column to the lever of valve V2 in the
discharge pipe 2 of the apparatus, in connection with which the regulator is
supposed to work, the connection being such that as the solution column falls it will
open the valve, and as it rises it will close the valve. The flexible inflow pipe 2
for the solution enters the solution column near one of the pivots 2¹ and extends to
near the closed end of the column. The outflow for the solution column is at h³
through the other pivot 22, and it is manifest that by the flow of the concentrated
solution into and out of the column the solution in the latter is maintained at
the density of the concentrated solution, as in the case of each of the solution
columns herein before described. The density of the solution is regulated by
moving the counterpoise weight W³ nearer to or farther from the pivot bearings,.
according as it is desired to diminish or increase the density of the solution
flowing away from the apparatus. To give this construction greater mechanical
power, the end of the column G2 farthest from the pivots may be enlarged, to
a globular form for example, so that the column may hold a greater quantity of
solution and at the point of greatest mechanical advantage.
In the several figures, the density regulator is illustrated as controlling the flow
of solution through the apparatus, and so the density of the concentrated solution,.
by regulating the flow of the concentrated solution through the discharge pipe of
the pan, but the density may also be regulated, though not so closely, by having
the automatic regulator control the flow of dilute solution into the pan. Thus, in
Figure 2, we may assume that the pipe 6 is the discharge pipe of the B¹,
pump
that is the suction pipe of the pump and brings the dilute solution to be
concentrated to the pump, and that the pump draws dilute solution from the
pipe cand delivers it through the pipe 6 into the pan. The pipe s¹ would be the
discharge pipe of the pan, and the float f¹ be connected to the valve v to open it
when the liquor in the pan should rise to and above a certain level, say that of the
dotted line, and to close it when it falls below the said line. Thus arranged to
regulate the flow into the pan, the operation would be as follows: The pan would
first be charged with solution by opening by hand the throttle valve t in the steam
pipe of the pump B', and keeping it open until the pan should be filled with
solution to a proper height and then steam would be turned into the pan through
the main S. As the evaporation of the solution proceeded the feed of the dilute
solution might be continued by hand until the solution in the pan had reached, or
nearly reached, the density desired, and then the small pump N, for circulating
the solution through the column G¹ be started, and thereafter the regulator be
allowed to control the feed. The density in the pan having reached the density
for which the regulator was set, the latter would permit a constant or intermittent
flow of solution into the pan to maintain the density constant, and the pan would
gradually fill up to a level at which, the float fwould open the valve v² in the
discharge pipe s¹, which would thereafter allow the concentrated solution to flow
away in proportion as the thin solution was allowed to flow into the pan, and the
density of the outflowing solution would thus be maintained at approximately the
density for which the automatic density regulator had been set.

page_text: In the operation of this density regulator, I prefer to have the density in the
solution column maintained as near as may be the same as the density of the
solution leaving the apparatus, but it may occur in cases when the solution is con-
centrated to a high degree of viscosity, or at times on other accounts, that it will
be desirable to have the solution in the column maintained at a lower density,
though still one which will increase and diminish with the density of the solution
leaving the apparatus. This may be effected by maintaining, through a suitable
connection, a small uniform flow of water, or of dilute solution, into the bottom of
the solution column. As the flow of concentrated solution up through the column
is also uniform in quantity, the density of the mixture will increase and diminish
with that of the concentrated solution, and its variations will serve to operate the
automatic regulator as hereinbefore described.
The foregoing illustrates various ways of applying my invention, which consists
in the employment of the weight of the column of solution having a density which
varies with the density of the concentrated solution flowing away from the vacuum
pan (which in the particular construction of pan shown is practically that of the
mass of liquor in the pau) acting through suitable mechanism to control the flow
of solution through the evaporating pan. The solution column may be differently
arranged and located, for rough work the depth of liquor in the pan itself may be
used for the solution column, and the mechanism through which the weight of the
solution column acts may be variously arranged, for example, a modification which
readily suggests itself would be, in the arrangement shown in Figure 2, to use a
tail pump B driven by an electric-motor, and have the rise and the fall of the
lever J¹ make or break the electric circuit connecting to the pump motor.
It is to be understood that my improvements are adapted to evaporating
apparatus of any character where there is to be a discharge only after the con-
centration of the liquid has reached such a stage that a given density is secured.
The improvements may be applied to multiple effects as well as to single effects,
and is also applicable to such apparatus as extractors or any apparatus in which
solutions of substances are made and in which the density of the resulting solution
depends upon the rate at which the solution is run through the apparatus.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is:
First. The automatic regulator for regulating the density of solutions sub-
stantially as described and shown.
Second. The combination with the controlling device for controlling the flow
of solution through the vessel of means connected therewith and operated by the
varying density of the concentrated solution leaving the vessel, to stop or start,
or to increase or decrease the flow of the solution as the density of the dis-
charging solution increases or diminishes above or below the desired degree.
Third. The devices for operating the controlling valve consisting of a diaphragm
connected therewith and acted upon by a column of concentrated solution, and
counterbalanced by a counterpoise column of water or other liquid.
Fourth. The modification of the automatic regulator in which the diaphragm
acted upon by the concentrated liquor is counterbalanced by a weighted lever.
Fifth. The modification of the automatic regulator shown in Figs. 3, 4 and 5,
employing a weighted lever actuated by the concentrated solution to operate the
controlling valve.
SAMUEL MORRIS LILLIE.
Haseltine, Lake & Co.,
45 Southampton Buildings, London, W.C., Agents for the Applicant.