IMPROVEMENTS IN THE MANUFACTURE OF CARBONATE OF SODA, AND IN THE PROCESSES AND APPARATUS USED IN SUCH MANUFACTURE
Year: 1876

page_text: LETTERS PATENT to Ernest Solvay, of Brussels, in the Kingdom of Belgium,
Manufacturer, for the Invention of "IMPROVEMENTS IN THE MANUFACTURE OF
CARBONATE OF SODA, AND IN THE PROCESSES AND APPARATUS USED IN SUCH
MANUFACTURE."
Sealed the 18th July 1876, and dated the 8th March 1870.
PROVISIONAL SPECIFICATION left by the said Ernest Solvay at the Office
of the Commissioners of Patents on the 8th March 1876.
"
IM-
ERNEST SOLVAY, of Brussels, in the Kingdom of Belgium, Manufacturer.
PROVEMENTS IN THE MANUFACTURE OF CARBONATE OF SODA, AND IN THE PROCESSES
AND APPARATUS USED IN SUCH MANUFACTURE."
My Invention relates to the manufacture of carbonates of soda by the process
generally known as the ammoniacal process, for which Letters Patent were granted
to me dated the Eleventh of December, 1863, No. 3131, and the Eighteenth of
May, 1872, No. 1525.
My present Invention having reference to divers processes and apparatus used in
the said manufacture, I will proceed to describe each of my improvements separately
in relation to the part of the manufacture to which it is applied. The manufacture
of carbonate of soda by the ammoniacal process is now well known, having been
fully described in the Specification of 'my said Letters Patent of 1863.
The first part of my Invention relates to the process of decantation, and is as
follows In the manufacture of soda by the ammoniacal process it sometimes
happens that liquids have to be decanted. This decantation is particularly, useful
in the purification of natural salt water in the distillation of ammonia when it is
required to recover from the liquid the chloride of sodium or of calcium it contains;
the liquid must then be separated from the lime it carries away with it from the
distillation. For this purpose I use a continuous decanter, consisting of a vessel,
into which the distilled liquid from the boiler is made to enter by a central tube,
and passes into the body of the decanter between the surface of the liquid already
in the decanter and the bottom of the decanter, thus causing the liquid to rise to
the surface before leaving the apparatus, and the lime or deposit to fall to the
bottom, from which it is drawn off through a cock or tap or other suitable means.
A scraper actuated by suitable means causes the lime to settle at the bottom of
the apparatus, and a cone actuated by a lever or otherwise prevents the liquid from

page_text: shaking up the deposit already formed. The said decanter may be used wherever
liquids employed in the above named manufacture have to be decanted. A chimney
is provided when necessary for the escape of steam.
My Invention relates, secondly, to improvements in the apparatus for cooling
carbonic acid mechanically. The cooling of carbonic acid is effected by expansion
and the exertion of power. I provide the machine with a second pump barrel
placed in any suitable position. The pistons of the two pump barrels are connected
together, but the piston of the second pump barrel acts in connection with the
motive power. The gas being first compressed in the compressor pump to a
higher pressure than is required for use, the compressed gas passes into the second
pump barrel and there expands, and in expanding acts as a motivo power till the
pressure is sufficiently reduced for it to be introduced into my absorbing columns.
By thus allowing the gas to expand and utilizing the power produced by expansion,
I am able to cool the gas to a very low temperature.
My Invention relates, thirdly, improvements in the absorber described in the
Specification of my Letters Patent of 1872, and it consists in giving a certain
amount of vertical play to the false bottoms by means of guides or by maintaining
the false bottoms in a fixed position by means of a central rod screwed at its
upper end so as to allow of the false bottoms being raised when required, also
in providing valves opening inwards to prevent the escape of liquid from the
column.
My Invention consists, fourthly, in the improvements herein-after described in
the vacuum filters used in my manufacture.
In order to spread the bicarbonate uniformly upon the filter, and for it to.be
suitably lixiviated, I employ a revolving pipe perforated with holes or grooved so
that the said pipe will be caused to revolve from the effects of reaction when the
liquid escapes.
Also for the purpose of creating a vacuum I use a pump provided with a water
piston, which is a novel application of such pump, and one to which it is well
adapted, as it entirely prevents dead space, and the water serves for lixiviating the
ammonia drawn in with the air or gas, thus protecting the metal parts of the
pump which otherwise would be injured by the gas.
The application of water piston pumps to effecting the lixiviation is effected by
interposing a reservoir between the filter and pump so as to prevent the filtering
liquid from mixing with the lixiviating water contained in the pump, which may
be salt water, as the ammonia to be lixiviated is carbonate of ammonia or caustic
ammonia, which is dissolved in the salt water before the said water passes on to the
ammonia dissolver. The valves are placed in the covers of the pump chests, and
thus produce no perturbation in the motion of the water.
My Invention relates, fifthly, to means for reducing the degree of alkaline force
or purity of soda. It is important, in a commercial point of view, that salts of
soda should be manufactured of any required degree of alkaline purity. I obtain
this result in the process of lixiviating the salt upon the filter by using a brine of a
density proportionate to the degree of alkaline force or purity of the soda I wish to
produce, or by mixing in suitable proportions pure water with brine of a given
density.
My Invention relates, sixthly, to the scraping apparatus used in the treatment of
bicarbonate or carbonate of soda. In the decomposition of bicarbonate, as also in
the calcination of carbonate of soda, if effected in apparatus heated exteriorly, such
as is described in the Specification of my Patent of 1872, and especially where a
high temperature is used, it is requisite that the heated surfaces should be scraped
whilst the salt is being stirred. For this purpose I employ in the apparatus
improved inclined scrapers jointed loosely upon an arm so as to be capable of
motion upon the said arm, and resting by their own weight upon the surface to be
scraped, with which they are made to form an obtuse angle in front.
My Invention relates, seventhly, to apparatus for the twofold purpose of drying
the bicarbonate of soda and converting it into carbonate, and it consists of two

page_text: apparatus, each of which is applicable for drying and also for decomposing the
bicarbonate continuously. As is well known, there aro difficulties inherent to the
nature of the product which requires a temperature inferior to 59 degrees centigrade,
and moreover has a tendency to agglomerate in drying.
The object of the said apparatus is in the first case to subject the bicarbonate to
the action of gases of a temperature not exceeding the proper degree, and in the
second case to the action of gases or vapours of a very high temperature. In front
of the apparatus in which the operation is carried on I place a regulator of heat,
consisting of a vessel in which is a float which acts upon a damper. The heated
air enters the said vessel by a suitable pipe and communicates heat to the water in
the said vessel, and consequently causes the float to rise or fall; when the heated air
or gases have attained too high a temperature the float descends, and by means of a
lever raises the damper and admits cold air, which mixing with the overheated air,
reduces its temperature to the required degree before it passes into the drying
apparatus. If preferred, other regulators of heat may be substituted for the
regulator described.
The first-apparatus consists of a tubular or other suitably formed chest, either
vertical or horizontal, in which an agitator is caused to move very rapidly. The
bicarbonate, after being suitably divided, is introduced into the said chest, and is
there, by the action of the agitator, reduced into a high state of division, and
under the influence of a current of hot air it becomes transformed into a dry
powder or dust.
The second apparatus consists of an arrangement somewhat similar to what is
used in the purification of gas. The said apparatus consists of a chest, in which is
a screen of metal gauze or perforated sheet iron upon which the bicarbonate from
the filters is spread. Air or gases heated to the required temperature are introduced
either above or below, the said screen being either drawn or forced in through
suitable tubes.
My Invention relates, eighthly, to apparatus for reducing the density of the brine
for it to have always the required density, and it consists of a reservoir or vessel
in which is a float connected to a lever, which lever opens or closes the passage
into the said vessel of fresh water from a small tank; whenever the brine passing
through the apparatus is too highly saturated the said float is caused to rise, and
thereby to cause fresh water to flow in and dilute the brine as required.
My Invention relates, ninthly, to self-acting forcing apparatus for forcing liquids
from one apparatus into another, and at the same time measuring the said liquids.
It consists of a reservoir, into which the liquid is admitted through a suitable
valve box. In the said reservoir is a float, which rises as the liquid enters. When
the said float has reached the required level it abuts against a projection on a rod
and raises the said rod, and with it a valve, which thereby is made to close an
aperture in the reservoir and to act upon a lever which opens a valve and admits
into the apparatus compressed air or gas, which air or gas forces out the liquid
through a suitable valve box. The float descending with the level of the liquid
comes in contact with a stop and draws down the said rod and causes it to close the
admission of compressed air or gas and to open a valve so as to allow the said air
or gas to escape. Fresh liquid then enters and the operation is renewed; an
ordinary meter indicates the number of times that the operation has been repeated,
and the capacity of the apparatus being known the quantity of liquid forced out
may be readily ascertained.
My Invention relates, tenthly, to a self-acting weighing machine for weighing
the materials employed and manufactured, and it consists of a balance plato or
table, the charge upon which is held in equilibrium by a counterpoise. Upon the
said plate or table is mounted a support, to which a second plate or table is jointed
50 as to fall over unless retained in position by a catch which, by a suitable spring,
is made to engage with a second catch or hook attached to the side of the second
plate or table. A fixed vertical bar, when the first plate or table descends, forces
back the said spring and the catch arm.

page_text: The action of the machine is as follows:-The material to be weighed falls
from a hopper on to the second plate of the machine, and when the required
quantity is upon the said plate the said plate and parts connected therewith descend
and the catch arm is forced back; the plate then falls over and empties its contents
into a hopper disposed for the purpose. When empty the plate is raised up again
by the action of a weight, and the lower plate rising, causes the catches to engage
one with the other, and the parts resume their former position.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Ernest Solvay in the Great Seal Patent Office on the 31st August
1876.
ERNEST SOLVAY, of Brussels, in the Kingdom of Belgium, Manufacturer. "IM-
PROVEMENTS IN THE MANUFACTURE OF CARBONATE OF SODA, AND IN THE PROCESSES
AND APPARATUS USED IN SUCH MANUFACTURE."
My Invention relates to the manufacture of carbonate of soda by the process
generally known as the ammoniacal process for which Letters Patent were granted
to me, dated the Eleventh of December, 1863, No. 3131, and the Eighteenth of
May, 1872, No. 1525.
My present Invention having reference to different processes and apparatus used
in the said manufacture, I will proceed to describe each of my improvements
separately in relation to the part of the manufacture to which it is applied. The
manufacture of carbonate of soda by the ammoniacal process is now well known,
having been fully described in the Specification of my said Letters Patent of 1863.
The first part of my Invention relates to the process of decantation, and is as
follows In the manufacture of carbonate of soda by the ammoniacal process it
sometimes happens that the liquids have to be decanted. This decantation is
particularly useful in the purification of natural salt water in the distillation of
ammonia. When it is required, after such distillation, to recover from the liquid
the chloride of sodium or of calcium it contains, instead of. letting them escape into
the sewers, the liquid must be separated from the lime it carries away with it from
the distillation. For this purpose I have invented a continuous decanter which I
will now proceed to describe in its application to the decantation just alluded to.
It presents several advantages over the large tanks used hitherto, as it requires but
little space, whilst it allows of the deposit being regularly and continuously drawn
off in a compact state. The said decanter is represented in section in Fig. 1 of the
accompanying Drawings. The boiler having been isolated, the distilled liquid to
be expelled therefrom by means of extra pressure if required, is conducted into the
central tube B by the pipe C. The steam escapes into the chimney D whilst the
said liquid descends in the tube B, and is decanted into the body A of the decanter,
in which it rises to the outlet pipe E and flows out through the pipe F. The lime,
which is caused to settle at the bottom of the apparatus, by the action of a scraper G
actuated from the hand wheel H by means of suitable gearing or otherwise is
drawn off through the cock or tap I. If preferred, the lime may be brought to the
side of the apparatus by means of a second pipe, one end of which opens into tho
bottom of the apparatus and its other end is situated at the side of the said
apparatus. The pressure of the liquid inside forces the lime up the said pipe; K is
a cone actuated by the lever M and rod N for the purpose of preventing the liquid
from washing away the deposit already formed.
The decanter above described may be varied in many ways, and may be arranged
differently to give the same results. The said decanter may be used not only for
decanting distilled liquids, but also, wherever it is required, to decant any of the
liquids employed in the said manufacture. I therefore claim the said decanter in all
its applications to the manufacture of carbonate of soda from ammonia.
It is needless to remark that if the said decanter be used for the decantation of

page_text: a liquid which does not emit steam the chimney would be unnecessary. Also, if the
liquid was poured in very gently the cone K might be omitted. The agitation of
the liquid, though advantageous, is not indispensable to the success of the operation
unless there be adherence of the material to the sides of the apparatus.
My Invention relates, secondly, to improvements in the apparatus for cooling
carbonic acid. The cooling of carbonic acid is effected by expansion and by the
exertion of power. The power obtained must not be wasted, in order that the
temperature may, if required, be brought down to several degrees below freezing
point. For this purpose I adapt to the machine a second pump barrel, which may
be placed either behind or in front of the compressor pump, or otherwise. The two
pistons being connected together, but the piston of the pump barrel being made to
act in connection with the motive power, I first compress the gas in the com-
pressor pump to a higher pressure than is required for use, and I then cause the
compressed gas to pass into the extra pump barrels above mentioned and there
allow it to expand, and in expanding to act as a motive power until the pressure
of the said gas is reduced to the required extent for it to be introduced into my
absorbing columns. By thus allowing the gas to expand and at the same time
utilizing the power produced by expansion, I am able to cool the said gas to a very
low temperature without any expense. I would however remark that this mode
of refrigeration is not indispensable to the manufacture of carbonate of soda,
My Invention relates, thirdly, to improvements in the absorber.
The improvements herein-after described, in the absorbing apparatus described
in the Specification of my Letters Patent of 1872, will be found useful in practice.
Firstly, the perforated plates or false bottoms of the absorbing columns should be
secured, so as not to allow of their taking an abnormal position. For this purpose
at first I fixed them entirely to the apparatus, but I discovered that whilst they
should be fixed horizontally a certain amount of play may be allowed them in
a vertical direction; this I effect by placing guides within the apparatus, as shewn
at G, Fig. 2, or otherwise. The said false bottoms may, if preferred, be maintained
in a fixed position by means of a central rod A (Fig. 3) screwed at its upper end
so as to allow of the false bottoms F being raised when required; Fig. 4 represents
a plan and sectional elevation of one of the false bottoms drawn to a larger scale.
Secondly, at that part of the said apparatus where the liquid enters it I apply
valves R, opening inwards, for the purpose of preventing the liquid from leaving
the columns in case of accident or stoppage; similar valves may be placed in the
inlet gas pipe at E, Fig. 3.
My Invention consists, 4thly, in the improvements herein-after described in the
vacuum filters used in my manufacture, by which improvements the working of
the said filter is facilitated and rendered more efficacious, both as regards the
separation of the liquids and their intended destination, viz, the drying or
decomposition of the bicarbonate of soda.
My improved filter is represented in Fig. 5 of the accompanying Drawings.
The liquid charged with bicarbonate is conducted into the filter by a pipe K, and
when I have drawn off from the columns the required quantity of liquid by
turning the cocks or taps X and Y, I introduce through the pipe L the water
necessary for washing.
"
My Improvements are as follows :—
1stly. In order to spread the bicarbonate uniformly upon the filter, and to wash
it suitably, I employ a revolving pipe Z perforated with holes or grooved, so that
the said pipe will be caused to revolve by the effects of reaction when the liquid
escapes.
2ndly. To obtain a vacuum I use a pump provided with a water piston,
which is a new application of such pump, and one to which it is perfectly adapted,
as it nearly entirely prevents dead space; and the water serves for washing the
ammonia drawn in with the air or gas, thus protecting the metal parts of the
pump, which otherwise would be speedily injured by the gas.
The application of water piston pumps to washing is effected by interposing

page_text: between the filter and pump a reservoir Q, Fig. 5, so as to prevent the filtering
liquid from mixing with the washing water. The said washing water contained
in the pump may be salt water, as the ammonia to be washed is carbonate of
ammonia or caustic ammonia, which is dissolved in the salt water before such
water passes on to the dissolver of ammonia.
Figs. 6, 7, and 8 illustrate my improvements in the details of construction of
the pump herein-before described. Fig. 6 is a transverse section through one of
the water chests; Fig. 7 is a longitudinal section of the pump, partly in elevation;
Fig. 8 is a plan of the same. A is the body of the pump; P is the piston;
B, B, are the chests in which the water pistons B' move; C, C, are the covers;
R, the outlet valves; S, the suction valves; O, cocks or taps for admitting water
into the pumps.
The improvements consist chiefly in the arrangement of the valves, which being
placed in the covers do not produce perturbation in the motion of the water, also
in the relative dimensions and shape of the water chests. The action of these
pumps is similar to that of ordinary pumps. A vacuum is produced in the
reservoir Q, Fig. 5, through the pipe V, and the liquid from the filter enters the
said reservoir through the pipe W. From the said reservoir Q the liquid passes
on to the apparatus for distilling the ammonia. Two, or more than two, of these
separating reservoirs are used alternately, and if preferred they may be placed
directly underneath the filter.
My Invention relates, 5thly, to means for reducing the alkaline force or purity
of soda. It is important in a commercial point of view that salts of soda of all
degrees of alkaline force or purity should be manufactured, and it is usual to vary
the alkaline force of the salts of soda by adding sea salt thereto. I obtain this
result in the process of washing the salt upon the filter by employing brine of a
density proportionate to the alkaline force or purity of the soda I wish to produce.
Thus, by using brine of 25 degrees Beaumé I obtain soda at 52 per cent. Brine
marking 18 degrees Beaumé will give soda at 54 per cent. Or I obtain the same
result by mixing in suitable proportions pure water with brine of always the same
density.
My Invention relates, 6thly, to the scraping apparatus used in the treatment of
bicarbonate or carbonate of soda. In the decomposition of bicarbonate as well as
in the calcination of carbonate of soda, if effected in apparatus heated exteriorly,
such as that described in the Specification of my Patent of 1872, and which
apparatus as now completed is represented in Figs. 9 and 10 of the accompanying
Drawings, it is very important, especially when a high temperature is used, that
the heated surfaces should be scraped whilst the salt is being stirred. I have had
great difficulty in carrying out this scraping operation, but have succeeded
completely by placing the scrapers in an inclined position as regards the surface
to be scraped, so that in front they form an obtuse angle with the said surface.
By this means the sharp edges of the scrapers remove the salt of soda which may
adhere to the surface. In order that the said scrapers should keep the scraped
surface perfectly clean they are made to rest upon it by their own weight, being
jointed at their other ends to an arm which traverses them. Fig. 11 represents
an edge view and a side view of one of the said scrapers; C is the scraper, which
is free to move partially round the driving arm B; S represents the surface to bo
scraped, and the direction in which the scrapers move is indicated by the
arrow F. The said cutters or scrapers may vary in shape to suit the apparatus
in which they are used, so that whether the surface be plane or curved they will
scrape it in every part. The said apparatus may vary greatly. Thus, in the
apparatus represented in Figs. 9 and 10 the vessel in which the bicarbonate is
placed is a portion of a sphere; B is the rotatory shaft carrying the arm C, to
which are jointed the cutters or scrapers D.
My Invention relates, 7thly, to apparatus for the twofold purpose of drying the
bicarbonate and converting it into carbonate. Many apparatus have been
proposed for effecting the reduction of bicarbonate of soda into carbonate. The

page_text: preparation of bicarbonate of soda to give it a commercial value is of very great
imanufacturing importance, and yet little attention has been paid to it, as it
appears to imply only a simple process of dessication; and as those who have
treated of my branch of manufacture have not had to operate practically on large
quantities the process appeared to be simple enough for a mero indication to
suffice without its forming the subject of special study. There are however
difficulties inherent to the nature of the product. It requires a temperature
inferior to 59 degrees centigrade, and moreover has a tendency to agglomerate in
drying.
I have invented the two apparatus herein-after described, which may be used for
treating large quantities of the material, and either for drying the bicarbonate or
for forming carbonate. This result. is very important as the same workmen can
attend to either operation.
The object of the said apparatus is in the first case to subject the bicarbonate to
the action of gases of a temperature not exceeding the proper degree, and in the
second case to tho action of gases or vapours heated to a high temperature. In front
of the apparatus in which the operation is effected I place a regulator of heat to be
used when the said apparatus is used for drying bicarbonates. The said regulator
may be of any suitable kind, but I prefer using for the purpose a regulator which
I have invented, and which is represented in Fig. 12. The hot air is conducted into
the said regulator by the pipe T. The said air communicates more or less heat to
the water contained in the reservoir R, and consequently causes the float F to fall
or rise. When the heated air or gases have attained too high a temperature the
float F descends, and by means of a lever L raises the damper r, whereby cold air is
admitted and mixes with .the overheated air and reduces its temperature to the
required degree before it passes into the drying apparatus through the pipe T¹.
I will now proceed to describe the two apparatus herein-before referred to.
First Apparatus.-The bicarbonate after having been suitably divided by being
shaken in a double grating or other suitable apparatus is made to pass into a chest
by preference of tubular shape, either vertical or horizontal, in which chest an
agitator is caused to move very rapidly. The bicarbonate is thus reduced into a
high state of division, and under the influence of a current of hot air raised
previously to the required temperature (if the apparatus be used for dessication) it
becomes transformed into powder or dust which is collected in a separate chamber.
It will be readily understood that the agitator may be disposed in many different
ways, as also the inlet and outlet of the material and of the hot air. If the chest
be horizontal, the agitator should be arranged to give an advancing motion to the
bicarbonate so as to cause it to travel through the entire space in which the agitator
acts. A vertical dessicator constructed according to my Invention is represented in
Fig. 13. A is the distributor into which the bicarbonate to be dried is thrown, and
in which a scraper M actuated by the shaft N causes the said bicarbonate to pass
through the hole c into the cylinder C. In the said cylinder a shaft S provided with
wings U revolves very rapidly. The said wings agitate the bicarbonate and reduce
it to powder, so as to bring it intimately into contact with the hot air of the required
temperature which enters through the pipe T¹. The dried bicarbonate or the
carbonate falls into the chest E from which it is removed through the door G, whilst
the air escapes by the chimney H.
Second Apparatus. My second apparatus consists of an arrangement somewhat
similar to what is used in the purification of gas, but applied in a different manner,
for whereas in gas works the object of the apparatus is to subject the gas to
chemical action, my apparatus is used to operate on solid matter by physical action
produced by the heat of the gas used.
My second apparatus, which is represented in Fig. 14, consists of a chest A
provided at a certain level with a screen B of metal gauze or perforated sheet iron
upon which the bicarbonate removed from the filters is spread. Air or gases heated
to the required temperature are introduced either above or below the said screen as
desired, being drawn or forced in through the tubes T and T¹.

page_text: When it is required to operate upon a considerable quantity of material several
of the said drying apparatus are used. In that case they are connected together by
means of distributing apparatus such as is used in gas purifiers, for the purpose of
alternately isolating each of the said apparatus to empty and replenish them.
In both of the apparatus herein-before described, if used simply for drying the
bicarbonate and if it be not required to collect or recover the gases by which the
heat is communicated the said gas may be allowed to escape, but if the said
apparatus be used for decomposing the bicarbonate, or if the gases be taken, say,
from a lime kiln, after traversing the bicarbonate they should be collected and
conducted to wherever the carbonic acid is to be used. If steam be used for
decomposing the bicarbonate, the said steam should be sufficiently superheated for it
not to be condensed when traversing the bicarbonate, or at all events for the con-
densation produced at the commencement of the operation to be taken up by the
subsequent passage of steam.
My Invention relates, 8thly, to apparatus for reducing the density of brine to the
required degree. The brine generally contains too little rather than too much salt,
and in the course of the manufacture it is still further exposed to be diluted. But
when it does happen that the ammoniacal brine contains too much salt, the said salt
is deposited on the pipes and causes obstructions. To prevent this happening I
have invented an apparatus by which the brine is always kept at its required
density. An apparatus constructed according to this part of my Invention is
represented in Fig. 15 of the accompanying Drawings. The brine enters the com-
partment A of the reservoir R through a tube T, it then passes through the pipe T¹
into the compartment B whence it passes through the tube O into the apparatus
herein-before described. In the compartment A is a float F which by means of a
lever L causes fresh water to flow from the small tank S (in which the same level
is constantly maintained) through the pipe V whenever the float rises, that is to say,
when the water is too highly saturated. The pipe V is made flexible by means of
an india-rubber joint piece y, so as to provide for any oscillations. The water
leaving the said pipe V flows into the funnel E and through the pipe z into the
pipe T, where it mixes with the brine flowing through the said pipe T. Fresh
water enters the small tank S through the tube M and the surplus water escapes
through the tube N. The said apparatus is very sensitive and enables the density
of the brine to be regulated with great precision.
7"
My Invention relates, 9thly, to a self-acting forcing apparatus. This apparatus
which is used for forcing liquids from one apparatus into another, and for measuring
the said liquids at the same time, is represented in Fig. 16 of the accompanying
Drawings. It consists in a reservoir R into which the liquid enters through tho
valve box C. The flow of liquid causes the float F to rise, and when the said float
has reached the required level it abuts against a washer fixed upon the rod t and
raises the said rod and with it the valve 8 which thereby is made to close the
aperture S. It also acts upon the lever L which raises the valve S and admits
into the apparatus compressed air or gas, which air or gas forces out the liquid
through the valve box C¹. The float F then descends with the level of the liquid,
and coming in contact with the washer or stop draws down the rod t which
closes the admission of compressed gas and opens the valve S so as to allow the gas
in the apparatus to escape. Fresh liquid then enters through the valve box C and
the operation is commenced over again, and is renewed according to the quantity
of liquid entoring the apparatus. An ordinary meter applied to the lever L indicates
the number of times that the apparatus has worked, and the capacity of the said
apparatus being known the total quantity of liquid forced out may be readily
ascertained. For ammoniacal liquors it may be advantageous to wash the gas
as it leaves the forcing apparatus, and to prevent loss of ammonia carbonic acid may
be used for effecting the operation.
My Invention relates, 10thly, to a self-acting weighing machine. For weighing
the different materials employed and manufactured I have invented a self-acting
weighing machine, represented in Fig. 17 of the accompanying Drawings. The said

page_text: machine consists of a balance plate or table P, the charge upon which is held in
equilibrium by a counterpoise Q. Let us suppose that the said counterpoise Q
counterbalances, say, one hundredweight of material above the weight of all the
apparatus or parts herein-after described. Upon the plate or table P is mounted a
support S to receive a plate or table P', which plate or table P1 is jointed to the
said support S near one end of its under side, as shewn, and would tumble over to
the right round the joint p if it were not retained in position by a catch e which by
a suitable spring is pressed up against and so as to engage with a catch or hook
attached to the side of the plate or table P¹. F is a fixed vertical bar which when
the plate P descends forces back the said spring and the catch arm e bý an inclined
projection on the said catch arm moving along it.
The action of the machine is as follows:-The material to be weighed falls from
a hopper or funnel T on to the plate P¹, and when one hundredweight of the
material (the machine being supposed, as stated, to be constructed for a charge of
one hundredweight) is upon the plate P' the said plate and parts connected there-
with descend, and the catch arme by moving on the bar F is forced back and the
catch e disengaged from the catch on the plate P', which plate falls over and empties
its contents into the hopper T. As soon as it is emptied the plate P¹ is raised up
again by the action of the weight q, and the plate P being raised by the action of
the weight Q causes the catch e again to engage with the catch on the plate P¹,
thereby bringing back all the parts into their former position. A meter indicates
the total quantity weighed. It would be easy to close the lower aperture of the
hopper T when the plate P¹ falls over; but when the quantity of material fed
regularly on to the plate P¹ is not too large, the apparatus may be casily regulated
without paying attention to what falls from the hopper T whilst the plate P¹ is
turning over.
Having now described the nature of my said Invention, and in what manner
the same is to be performed or put in practise, I wish it to be understood that I do
not confine myself to the precise details herein-before described and illustrated in the
accompanying Drawings, as the same may be varied without departing from the
nature of the said Invention; nor do I claim the details of the said apparatus except
as parts of apparatus for carrying out the above-mentioned manufacture; but I
claim as my said Invention,-
Firstly. With reference to the decanters, the combination, adaptation, and
arrangement of parts of decanting apparatus herein-before described and illustrated
in the accompanying Drawings by which the liquid to be decanted is introduced
between the surface of the liquid already in the apparatus and the bottom of the
said.apparatus, thus causing the liquid under treatment to ascend before leaving
the apparatus, and the deposit is removed through an aperture or pipe at the
bottom of the apparatus, which is so arranged that the deposit there accumulates.
Secondly. With reference to the mechanical cooling of carbonic acid I neither ·
claim the principle of cooling gas by causing it to expand, nor of cooling it by
causing it to exert power, but I claim the apparatus herein-before described placed
between the carbonic acid gas forcing machine and the absorber, in which apparatus
the carbonic acid gas compressed in the said forcing machine is made to exert
mechanical power, which power is given back to the said machine and cools the gas
passing into the absorber, essentially as described.
Thirdly. With reference to the absorber I claim the application thereto of guides
or of a central rod and of valves, essentially as described and for the purposes set
forth.
Fourthly. With reference to the apparatus for filtering liquids containing
bicarbonate of soda I claim the application to the vacuum filters of a revolving
pipe perforated with holes or grooved for the purpose of spreading the liquid to be
filtered or the liquid for washing uniformly upon the filter; also the application of
a pump provided with water pistons to create a vacuum by the interposition of a
reservoir into which the filtered liquid passes.

page_text: Fifthly. With reference to reducing the alkaline strength or purity of the soda I
claim the introduction into the filter of a solution of salt to reduce the alkaline
strength of the carbonate of soda, essentially as described.
Sixthly. With reference to the scraping apparatus used in the treatment of
bicarbonate and carbonate of soda I claim the improved scrapers herein-before
described and illustrated in the accompanying Drawings, that is to say, scrapers
jointed loosely upon an arm so as to be capable of motion upon the said arm and
resting by their own weight upon the surface to be scraped in front of the said
alm.
Seventhly. With reference to the apparatus for the two-fold purpose of drying
the bicarbonate or converting it into carbonate, I claim the combination, adapta-
tion, and arrangement of parts constituting the two apparatus herein-before
described and illustrated in the accompanying Drawings, each of the said apparatus
being applicable for drying and also for decomposing bicarbonate of soda con-
tinuously, the first by means of an agitator to which rapid motion is communicated,
the second by means of screens or perforated plates connected together by a
distributor, both apparatus being arranged so that the material operated on comes
in contact repeatedly with the vapours or heated gases, the temperature of which
vapours or gases is suitably regulated.
Eighthly. With reference to the apparatus for reducing the density of the brine I
claim the application of the apparatus hercin-before described and illustrated in
Fig. 15 of the accompanying Drawings to reducing the density of the brine so as to
prevent obstructions without reducing it below the degree required for reaction to
take place.
Ninthly. With reference to the self-acting forcing apparatus I claim the
application to the aforesaid manufacture of the apparatus for forcing and measuring
liquids herein-before described and illustrated in Fig. 16 of the accompanying
Drawings.
Tenthly. With reference to the self-acting weighing machine I claim the combi-
nation, adaptation, and arrangement of parts of the self-acting weighing machine
herein-before described and illustrated in Fig. 17 of the accompanying Drawings.
In witness whereof, I, the said Ernest Solvay, have hereunto set my hand
and seal, this Twenty-fifth day of August, in the year of our Lord One
thousand eight hundred and seventy-six.