IMPROVED PROCESSES AND APPARATUS FOR MAKING OXYGEN AND HYDROGEN FOR THE PRODUCTION OF THE OXY-HYDROGEN LIGHT, FOR OBTAINING AIR RICH IN OXYGEN FOR VARIOUS PURPOSES, AND FOR OBTAINING AND UTILISING BYE- PRODUCTS
Year: 1881

page_text: LETTERS PATENT to Alexander Melville Clark, of 53, Chancery Lane, in the
County of Middlesex, Patent Agent, for an Invention of "IMPROVED
PROCESSES AND APPARATUS FOR MAKING OXYGEN AND HYDROGEN FOR THE
PRODUCTION OF THE OXY-HYDROGEN LIGHT, FOR OBTAINING AIR RICH IN
OXYGEN FOR VARIOUS PURPOSES, AND FOR OBTAINING AND UTILISING BYE-
PRODUCTS." A communication from abroad by Narcisse Alfred Hélouis, of
Paris France
PROVISIONAL SPECIFICATION left by the said Alexander Melville Clark
at the Office of the Commissioners of Patents on the 12th May 1881.
ALEXANDER MELVILLE CLARK, of 53, Chancery Lane, in the County of
Middlesex, Patent Agent. "IMPROVED PROCESSES AND APPARATUS FOR MAKING
OXYGEN AND HYDROGEN FOR THE PRODUCTION OF THE OXY-HYDROGEN LIGHT,
FOR OBTAINING AIR RICH IN OXYGEN FOR VARIOUS PURPOSES, AND
OBTAINING AND UTILISING BYE PRODUCTS." [A communication from abroad by
Narcisse Alfred Hélouis, of Paris, France.]
FOR
This Invention relates to improved processes and apparatus for the manufacture
of a mixture of oxygen and hydrogen gases for producing the oxyhydrogen light,
for obtaining air rich in oxygen for various purposes, and for obtaining and utilising
bye products.
According to this Invention the economy resulting from the simplicity of the
process of manufacture of the oxygen and hydrogen is supplemented by the
reduction of cost by the utilisation of the whole of the bye products in the reactions
hereafter described. The secondary products resulting from this process are
sulphuric acid, sulphurous acid, sulphites, alkaline carbonates and bicarbonates,
pyroligneous acid, &c.
The two gases, oxygen and hydrogen, are produced simultaneously in the same
furnace with the same kind of fuel, and in retorts which are identical in form and
working.
An example of the apparatus for the production of the gases is represented in
Figures 1 and 2 of the accompanying Drawings, Figure 1 being a longitudinal

page_text: section, and Figure 2 a horizontal section of the apparatus taken on line 1-2,
Figure 1. The furnace may contain any suitable number of retorts, but for greater
clearness three only are shown, two A, A, for the manufacture of oxygen, and one B
for the manufacture of hydrogen. Each support is surmounted by a cast iron
pipe m, which communicates at the rear end with the inner end of the retort, and
at the front end with the steam pipe T from a boiler for supplying superheated
steam to each retort; 0, 0¹, are Hues for conveying away the gases of combustion
to the shaft X; V are the flues of other apparatus hereafter described; F, furnace
chamber. Hydrogen gas can be economically obtained by passing steam over
charcoal at a red heat, but this method is but little used on account of the danger,
in case of leakage of the apparatus, of deleterious effects due to the carbonic oxide
which accompanies the hydrogen in the proportion of 30%. An analysis of the
gas produced by passing steam over charcoal gives for 100 parts of gas 55 of
hydrogen, 31 of carbonic oxide, and 14 of carbonic acid.
According to the present Invention hydrogen is produced in these apparatus free
both from carbonic oxide and carbonic acid. To attain this result the three
nascent gases, viz., hydrogen, carbonic oxide, and carbonic acid, are passed into a
cylinder containing sulphate of lime at a dull red heat obtained by a sand bath,
or in other suitable manner. The carbonic oxide reduces the sulphate of lime
(Ca O SO³), and transforms it into sulphide of calcium (Ca S), and is itself converted
into carbonic acid (CO). The mixture of hydrogen and carbonic acid on leaving
the above apparatus passes to an apparatus containing carbonate of soda (Na O CO³),
which is transformed into bicarbonate (Na O 2 CO²), and the hydrogen passes off
alone.
The products resulting from these operations conduce to the economical manu-
facture of oxygen in the manner next described. The wood charcoal employed in
the hydrogen retorts is manufactured by distilling wood in closed vessels. The
products of this distillation are employed in the following manner :- -(1.) The wood
charcoal for tlie hydrogen retorts. (2.) The gases of distillation as fuel for heating
the retorts by being introduced through tuyeres L beneath the furnace grate F,
Figure 1. (3.) The tar is utilised for carburetting the hydrogen.
(4.) The
pyroligneous acid is employed for disengaging a portion of the sulphurous acid
of the sulphites of soda and forming acetate of soda, which is afterwards converted
into pure acetic acid. The undecomposed portion of the sulphites is sold. The
carbonic acid produced in the manufacture of the hydrogen is employed to convert
the carbonates of soda into bicarbonates, of which a portion is utilised for con-
verting sulphite of lime into carbonate of lime and sulphite of soda, the remainder
being sold.
The economic process of manufacture of oxygen of this Invention is based on the
property possessed by silicic acid (sand) of displacing from their combinations
under the influence of heat the most powerful acids. The process comprises two
intimately connected successive treatments. A homogeneous mixture is first made
by mechanical means of
By the
This mixture is introduced into retort A. and raised to a dull red heat; at this
moment a current of superheated steam is injected through pipes T, m.
reaction which then takes place the sand combines with the lime (of the sulphate
of lime or plaster) to form silicate of lime, and a mixture of oxygen and sulphurous
acid is disengaged. The gases are conducted by the discharge pipe C through a
worm R to a vessel D containing caustic soda in solution in water, which absorbs
the sulphurous acid and forms sulphites of soda. The free oxygen traverses the
washer H containing milk of lime, which retains any sulphurous acid carried over

page_text: with the oxygen, and thence passes to a gas holder by pipe K. Two retorts A are
employed in order that the washers and gas holder may be supplied continuously.
The different products resulting from these reactions are utilised as follows:-
One portion of the alkaline sulphites produced in D is sold, while the remainder is
employed to produce sulphuric acid or oxygen. For this purpose the sulphite of
soda is treated with pyroligneous acid resulting from the distillation of wood, as
above mentioned, forming acetate of soda, which serves for the manufacture of pure
acetic acid, the sulphurous acid being set free. The sulphites of lime in washers H
are converted into sulphites of soda by the action of the bicarbonate resulting from
the manufacture of the hydrogen. The sulphurous acid disengaged from the
sulphites is mixed with oxygen, or preferably with air containing 75% of oxygen,
obtained by means of the apparatus represented in Figure 3, hereinafter described.
This mixture of sulphurous acid and air is conducted by the pipe a, Figure 4, into
a platinum cylinder b placed in a muffle, the temperature of which may be raised
at will. The portion x, y, of this cylinder is filled with pumice stone together with
a little spongy or scrap platinum, and it is heated to from 350° C. to 450° C., where-
upon monohydrated (or anhydrous if the gases have been previously dried) sulphuric
acid is formed. The acid is condensed in a refrigerating worm c, the lower end of
which is in cominunication with a bell chamber & placed in a stoneware vessel c.
A pipe in the top of the bell chamber permits of the escape of the uncombined
gases, the uncombined sulphurous acid being absorbed by an alkaline solution as
before.
The sulphuric acid thus produced is sold or brought to 60°, in order to be
transformed into oxygen and sulphurous acid in a platinum coil heated to redness
and filled with scraps of platinum, the gases being collected as above described.
into cylinder 1, which is
being exhausted of air.
controlled by a cock s;
cylinders n, n¹, p, p².
When the pressure in
The air containing 75% of oxygen required for the operation above described
is obtained in the following manner by means of the apparatus represented in
Figure 3. Three pumps, such as shown at k for example, are employed, driven
either from an engine or hydraulic motor, said pumps working in connection with
three pairs of superposed cylinders 1, l, m, n, p, p, capable of supporting a pressure
of 10 atmospheres. Atmospheric air is injected by pipe
filled with water containing 20% of glycerine, cylinder
The two cylinders are connected by two pipes t, t¹, both
the arrangement is the same for the two other pairs of
While air is being forced into cylinder the cock & is closed.
cylinder has reached 10 atmospheres the cock 8 is opened, and the water is dis.
charged into cylinder ", while the nitrogenous air remains in the cylinder ; the
cock 8 is then closed, and the excess of nitrogeneous air in cylinder ĭ is discharged
by opening pipe u, and the air rich in oxygen in solution in cylinder is then
purified by the second pump by pipe into cylinder n, which is filled with water
containing 20% of glycerine.
The same operation is repeated in cylinders n, n', as for cylinders I, ', and the
second solution is forced through the pipe into cylinder p, care being taken to
raise the pressure in each of these apparatus to 10 atmospheres. The air rich in
oxygen is collected in p¹ to be mixed with sulphurous acid, as above explained. The
water is raised at the end of each operation from the lower to the upper cylinders
by opening cocks 8, 81, 82, and forcing air into the upper cylinders by the
pipes 1, 2, the pressure causing the water to rise through pipes t. It should be
mentioned that the pressure is reduced one half each time the air rich in oxygen
passes from one of the upper cylinders 1, n. p, into one of the lower cylinders l', n¹, p¹,
from which the air has been previously exhausted. It is therefore necessary to
have two apparatus 1, ', to supply one apparatus n, n', at 10 atmospheres, and
two apparatus n, n', to one apparatus p,p. There will therefore be four apparatus,
two apparatus n, n', and one apparatus p, p', or three apparatus whose relative
capacities are as 1, 2, and 4. By increasing the number of apparatus almost pure
oxygen may be rapidly obtained by means of the improved system of superposed
cylinders which enable the undissolved nitrogenous air to be readily eliminated.

page_text: It is preferred to employ three pairs of cylinders and three pumps, which require
but small motive power for working, but by employing bydraulic or other motive
power the number of double cylinders may be increased so as to obtain air con-
taining 90 to 95% of oxygen.
The glycerine added to the water possesses the property of increasing its solvent
power for oxygen. The solution of oxygen in water at 10 atmospheres gives in
volumes
In the first cylinder about
In the second cylinder about
In the third cylinder about
38 of oxygen.
62 of nitrogen.
55 of oxygen.
45 of nitrogen.
75 of oxygen.
25 of nitrogen.
Other substances may also be employed in lieu of glycerine for obtaining air rich
in oxygen, as well as other suitable arrangements of apparatus. For example, I
may employ the following products, the use of which I claim in this apparatus,
viz., spirits of turpentine, solution of phosphate and carbonate of soda, alcohol (100
litres of which dissolves at the ordinary pressure 30 litres of oxygen and 30 litres
of nitrogen), quenched charcoal, such as used by bakers, the charcoal being put in
the cylinders and n¹, Figure 3. One hundred litres of charcoal is capable of
dissolving at a pressure of 10 atmospheres 900 litres of oxygen and 600 litres of
nitrogen. When the pressure is obtained in cylinders ', n¹, the cocks of the upper
cylinders containing glycerine and water at the same pressure are opened; under
the influence of the liquid the charcoal is caused to give up a small quantity of
oxygen and nearly the whole of the nitrogen which passes into the upper cylinder.
On exhausting cylinders 1, n², from 700 to 800 litres of oxygen are obtained in
each cylinder, containing only from 25 to 30 parts of nitrogen.
The three pairs of cylinders shown in the Drawing are reduced to two, viz., the
pairs of cylinders l, l', n, n'. The safety valves are dispensed with, as the apparatus
is calculated to support a pressure of 18 atmospheres and ordinarily works at
between 10 and 12 atmospheres. The air is pumped from a drum having a
capacity of from 200 to 300 litres, and consisting of a sheet iron cylinder capable
of supporting a pressure of two atmospheres. It is closed at top and bottom by
wire gauze screens of about 0.50 in diameter, between which is disposed a septum
formed of one or more thicknesses of taffeta, which has been previously dipped in
the following solution :-Sulphide of carbon, 400 parts; absolute alcohol, 20 parts;
ether, 10 parts; native black caoutchouc, 50 parts. Owing to the rapid evaporation
of the solvents the fabric becomes coated with a very thin and highly flexible layer
of caoutchouc. Other solvents which have been tried leave the caoutchouc in a
sticky condition, the stickiness being greater the slower the evaporation, whereas
the solution above specified, which is as limpid as water, produces by its rapid
evaporation exceedingly thin films of very pure caoutchouc. The drum is also
provided with a pipe communicating with the pump of the first apparatus, and as
the drum is gradually exhausted by the action of the pump the external air is
diffused through the dialysing septa, one half of its nitrogen being however
retained, so that the air which enters the drum consequently contains 40 per cent.
of oxygen (whereas atmospheric air contains but 21 per cent.), this air already
rich in oxygen being pumped into the apparatus as before described. By the above
described arrangements large quantities of oxygen at 95 per cent. can be obtained
in a few minutes. The dialysing drum berein described may be applied to forge
bellows, blowers, &c. for supplying air rich in oxygen, the employment of which
would be of the greatest advantage in metallurgy.
Figure 5 of the Drawings illustrates an arrangement of apparatus in which the
air is dialysed by means of an indiarubber septum, and utilized as above described.
The solvents for caoutchouc which I prefer to use are sulphide of carbon or light
spirit of petroleum marking 650°. I have however previously given the compo-
sition of a suitable solvent. The working of the apparatus comprises three

page_text: successive operations: 1st, pumping the air; 2nd, dialysis of the oxygen by means
of the septum; 3rd, expulsion of the nitrogenous air. The air may be pumped by
means of air pumps or steam aspirators." The Drawing shows the apparatus
provided with steam jet aspirators, which are much more economical in use than
pumps. a is a bag made of silk coated with caoutchouc and distended by an inner
frame of galvanised iron. This bag is enclosed in a sheet iron drum b, whose ends
are formed of wire gauze c, so as to permit of the free circulation of air around the
bag. is an india-rubber tube stiffened by an internal spiral of wire connecting
the bag with the aspirator e. The aspirator is composed essentially of a series of
cones placed one behind the other with a sufficient space between them. The
steam introduced through pipe g into the first cone ƒ induces a lateral current of
air; the jet of steam and air in escaping from the first cone acts in the same way
in the second cone, and so on in succession, and by employing four or five cones a
considerable volume of gas may be thus exhausted and forced by means of a small
steam jet. The aspirator c produces a partial vacuum in bag a, and the external
air is then caused to diffuse through the rubber coated silk fabric, but as a larger
proportion of oxygen than of nitrogen passes through the septum the air drawn in
will be richer in oxygen than atmospheric air, and will contain about 40 per cent.
of oxygen and 60 per cent. of nitrogen. The steam and enriched air thus drawn in
are forced by the steam jet into the refrigerator coil h, where the steam condenses
in drum i, while the gaseous mixture escapes through the pipe k at the upper part
of said drum into the second apparatus . This consists of a sheet iron drum
hermetically closed, and containing an india-rubber bag m similar to a, and provided
with two pipes n, o, the one for the admission of the oxygenated air, and the other
for the escape of the gas in excess. The pipe o dips into a column of water p, tho
height of which may be varied to regulate the pressure in l. The discharge by
pipe o is of considerable importance, as by it the non-dialysed nitrogen is carried
through the liquid p into the atmosphere. The bag m is exhausted by means of
an aspirator e' exactly similar to e. The air dialysed by passing through the
bag m contains about 60 per cent. of oxygen and 40 per cent, of nitrogen, and
may be conducted by pipe of refrigerator 8 into a third apparatus exactly similar
to I.
It is preferable to employ four apparatus in all, as shown, and on leaving the last
apparatus the air, then containing about 95 per cent. of oxygen, is stored in a gas
holder, not shown in the Drawing. The following are as near as possible the
results obtained with four such apparatus:-
Air dialysed by the bag in 1st apparatus = 40 per cent. of oxygen.

page_text: There remains in the retort sulphide of calcium, to which may be added the
sulphide already obtained by the reaction of the carbonic oxide on plaster in the
manufacture of hydrogen, as before described.
Figure 6 is an example of an apparatus which may be employed in carrying out
this process. The sulphide of calcium extracted from the retort is placed in a large
sheet iron cylinder H, closed at the ends by covers secured by screw clamps. A
small jet of steam is conveyed by pipe T into an aspirator N, similar to that repre-
sented in Figure 5, to which carbonic acid gas is conveyed by a pipe M from the
holder. The moistened carbonic acid is injected into cylinder H, together with
the small quantity of water resulting from the condensation of the steam jet. The
cylinder H may if desired be replaced by a series of iron columns, similar to the
coke columns of gasworks. The sulphide of calcium, under the influence of the
moist carbonic acid, is immediately converted into carbonate of lime, with an
abundant evolution of hydrosulphuric acid, which escapes at pipe V. A second
aspirator N conducts this sulphuretted hydrogen through a condenser A, which
retains the steam, to a burner K formed of a number of copper tubes placed upon
the discharge pipe B. The burner tubes are enclosed in a cast iron cucurbit Ċ in
which the combustion takes place. A current of dialysed air enters the burner at
pipe L from the dialysing apparatus before described. The burner is lighted by a
small gas jet placed above it. The sulphurous acid which is the product of this
combustion is conveyed into leaden chambers with dialysed air for conversion into
sulphuric acid, which may be used in the manufacture of pure oxygen, as before
described. The carbonate of lime residue which remains in the cylinder H is also
utilized.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Alexander Melville Clark in the Great Seal Patent Office on the
5th November 1881.
ALEXANDER MELVILLE CLARK, of 53, Chancery Lane, in the County of
Middlesex, Patent Agent. IMPROVED PROCESSES AND APPARATUS FOR MAKING
OXYGEN AND HYDROGEN FOR THE PRODUCTION OF THE OXY-HYDROGEN LIGHT,
FOR OBTAINING AIR RICH IN OXYGEN FOR VARIOUS PURPOSES, AND FOR
OBTAINING AND UTILIZING BYE-PRODUCTS." A communication from abroad by
Narcisse Alfred Hélouis, of Paris, France.
This Invention relates to improved processes and apparatus for the manufacture
of a mixture of oxygen and hydrogen gases for producing the oxy-hydrogen light.
According to this Invention the economy resulting from the simplicity of the
process of manufacture of the oxygen and hydrogen is supplemented by the
reduction of cost by the utilization of the whole of the bye products in the reactions
hereafter described. The secondary products resulting from this process are
sulphuric acid, sulphurous acid, sulphites, alkaline carbonates and bicarbonates,
pyroligneous acid, &c.
The two gases, oxygen and hydrogen, are produced simultaneously in the same
furnace with the same kind of fuel, and in retorts which are identical in form and
working.
An example of the apparatus for the production of the gases is represented in
Figures 1 and 2 of the accompanying Drawings, Figure 1 being a longitudinal
section, and Figure 2 a horizontal section of the apparatus.
The furnace may
contain any suitable number of retorts, but for greater clearness three only are shewn,
two A, A, for the manufacture of oxygen, and one B for the manufacture of
hydrogen. Each retort is surmounted by a cast iron pipe m which communicates
at the rear end with the inner end of the retort, and at the front end with the
steam pipe T from a boiler for supplying superheated steam to each retort; O, O',
are flues for conveying away the gaseous combustion to the shaft X; V, V, are the
flues of other apparatus hereinafter described; F, furnace chamber. Hydrogen gas
can be economically obtained by passing steam over charcoal at a red heat, but this
method is but little used on account of the danger, in case of leakage of the
apparatus, of deleterious effect due to the carbonic oxide which accompanies the
hydrogen in the proportion of 30 per cent. An analysis of the gas produced by
passing steam over charcoal gives for 100 parts of gas 55 of hydrogen, 31 of
carbonic oxide, and 14 of carbonic acid.
According to the present Invention bydrogen is produced in these apparatus free
both from carbonic oxide and carbonic acid. To attain this result the three nascent
gases, viz., bydrogen, carbonic oxide, and carbonic acid, are passed into a cylinder
containing sulphate of lime at a dull red heat obtained by a sand bath, or in other
suitable manner.
The carbonic oxide reduces the sulphate of lime (Ca O, SO³), and transforms it
into sulphide of calcium (Ca S), and is itself converted into carbonic acid (CO2).
The mixture of bydrogen and carbonic acid on leaving the above apparatus passes
to an apparatus containing carbonate of soda (Na O, CO), which is transformed
into bicarbonate (Na O, 2 CO²), and the hydrogen passes off alone.
The products resulting from these operations conduce to the economical manu-
facture of oxygen in the manner next described. The charcoal employed in the
hydrogen retorts is manufactured by distilling wood in closed vessels. The products
of this distillation are employed in the following manner :-(1). The wood charcoal
for the hydrogen retorts. (2). The gases of distillation as fuel for heating the
retorts introduced through tuyeres L beneath the furnace grate F, Figure 1.

page_text: (3). The tar is utilized for carburetting the hydrogen. (4). The pyro-ligneous acid
is employed for disengaging a portion of the sulphurous acid of the sulphites of
soda and forming acetate of soda which is afterwards converted into pure acetic
acid. The undecomposed portion of the sulphites is sold. The carbonic acid,
produced in the manufacture of the hydrogen is employed to convert the carbonates
of soda into bi-carbonates, of which a portion is utilized for converting, sulphite
of lime into carbonate of lime and sulphite of soda, the remainder being sold.
The economic process of manufacture of oxygen of this Invention is based on the
property possessed by silicic acid (sand) of displacing from their combinations
under the influence of heat the most powerful acids. The process comprises two
intimately connected successive treatments.
A homogeneous mixture is first made by mechanical means of,-
660 parts of plaster (sulphate of lime), and
340 parts river sand (silicic acid)= 1000 parts.
This mixture is introduced into retort A and raised to a dull red heat; at this
moment a current of superheated steam is injected through pipes T, m. By the
reaction which takes place the sand combines with the lime (of the sulphate of
lime or plaster) to form silicate of lime, and a mixture of oxygen and sulphurous
acid is disengaged. The gases are conducted by the discharge pipe C through a
worm R to a vessel D containing caustic soda in solution in water, which absorbs
the sulphurous acid and forms sulphites of soda. The free oxygen traverses the
washer H containing milk of lime, which retains any sulphurous acid carried
over with the oxygen, and thence passes to a gas holder by pipe K. Two retorts A
are employed in order that the washers and gas holder may be supplied
continuously.
The different products resulting from these reactions are utilized as follows:-
One portion of the alkaline sulphites produced in D is sold, while the remainder
is employed to produce sulphuric acid or oxygen. For this purpose the sulphite of
soda is treated with pyroligneous acid resulting from the distillation of wood, as
above mentioned, forming acetate of soda, which serves for the manufacture of pure
acetic acid, the sulphurous acid being set free.
The sulphites of lime in washers H are converted into sulphites of soda by the
action of the bicarbonate resulting from the manufacture of the hydrogen.
The sulphurous acid disengaged from the sulphites is mixed with oxygen, or
preferably with air containing 75 per cent. of oxygen obtained by means of the
apparatus represented in Figure 3, hereinafter described. This mixture of
sulphurous acid and air is conducted by the pipe a, Figure 4, into a platinum
cylinder placed in a muffle, the temperature of which may be raised at will. The
portion x, y, of this cylinder is filled with pumice stone together with a little
spongy or scrap platinum, and it is heated to from 350° C. to 450° C., whereupon
mono-hydrated (or anhydrous if the gases have been previously dried) sulphuric
acid is formed. The acid is condensed in a refrigerating worm c, the lower end of
which is in communication with a bell chamber d placed in a stone ware vessel e.
A pipe in the top of the bell chamber permits of the escape of the uncombined
gases. The uncombined sulphurous acid is absorbed by an alkaline solution as
before.
The sulphuric acid thus produced is sold or brought to 60°, in order to be
transformed into oxygen and sulphurous acid in a platinum coil heated to redness
and filled with scraps of platinuin, the gases being collected as above described.
The air coutaining 75 per cent. of oxygen required for the operation above described
is obtained in the following manner by means of the apparatus represented in
Figure 3. Three pumps, such as shown at k for example are employed, driven
either from an engine or hydraulic motor, said pumps working in connection with
three pairs of superposed cylinders l, l', n, n, p, p, capable of supporting a pressure
of 10 atmospheres. Atmospheric air is injected by pipe r into cylinder 1, which is
filled with water containing 20 per cent. of glycerine, while cylinder l' is exhausted
of air, The two cylinders are connected by two pipes t, t¹, both controlled by a

page_text: cock a; the arrangement is the same for the two other pairs of cylinders n, n', P, P.
While air is being forced into cylinder the cock 8 is closed. When the
pressure in cylinder 7 has reached 10 atmospheres the cock 8 is opened and the
water is discharged into cylinder ', while the nitrogenous air remains in the
cylinder ; the cock 8 is then closed and the excess of nitrogenous air in cylinder
is discharged by opening pipe u, and the air rich in oxygen in solution in
cylinder is then pumped by the second pump by pipe into cylinder n,, which is
filled with water containing 20 per cent. of glycerine.
The same operation is repeated in cylinders n, n', as for cylinders 1, 1, and the
second solution is forced through the pipe into cylinder p, care being taken to
raise the pressure in each of these apparatus to 10 atmospheres. The air rich in
oxygen is collected in p₁ to be mixed with sulphurous acid, as above explained.
The water is raised at the end of each operation from the lower to the upper
cylinders by opening cocks 8, s', s², and forcing air into the upper cylinders by the
pipes r,,, the pressure causing the water to rise through pipes t.
It should be mentioned that the pressure is reduced one half each time the air
rich in oxygen passes from one of the upper cylinders l, n, p, into one of the lower
cylinders, n', p', from which the air has been previously exhausted. It is
therefore necessary to have two apparatus 1, l', to supply one apparatus n, n', at
10 atmospheres, and two apparatus n, n', to one apparatus p, p₁. There will be
therefore four apparatus 7, 71, two apparatus n, n', and one apparatus p, p, or
three apparatus whose relative capacities are as 1, 2, 4. By increasing the number of
apparatus almost pure oxygen may be rapidly obtained by means of the improved
system of superposed cylinders which enable the undissolved nitrogenous air to be
readily eliminated.
It is preferred to employ three pairs of cylinders and three pumps, which require
but small motive power for working, but by employing hydraulic or other notive
power the number of double cylinders may be increased so as to obtain air
containing 90 to 95 per cent. of oxygen.
The glycerine added to the water possesses the property of increasing its solvent
power for oxygen. The solution of oxygen in water at 10 atmospheres gives in
volumes
In the 1st cylinder about 38 of oxygen.
"
"
"
2nd
"
"
دو
د,
62 of nitrogen.
55 of oxygen.
"
دو
"
"
45 of nitrogen.
3rd
او
"
"
75 of oxygen.
"
"
"
"
25 of nitrogen.
Other substances may also be employed in lieu of glycerine for obtaining air
rich in oxygen, as well as other suitable arrangements of apparatus. For example,
I may employ the following products, viz., spirits of turpentine, solution of
phosphate and carbonate of soda, alcohol (100 litres of which dissolve at the
ordinary pressure 30 litres of oxygen and 30 litres of nitrogen), quenched charcoal,
such as used by bakers, the charcoal being put in the cylinders and n¹, Figure 3.
One hundred litres of charcoal are capable of dissolving at a pressure of 10
atmospheres 900 litres of oxygen and 600 litres of nitrogen. When this pressure
is obtained in cylinders , n¹, the cocks of the upper cylinders containing glycerine
and water at the same pressure are opened; under the influence of the liquid the
charcoal is caused to give up a small quantity of oxygen and nearly the whole of
the nitrogen which passes into the upper cylinder. On exhausting cylinders l', n',
from 700 to 800 litres of oxygen are obtained in each cylinder containing only
from 25 to 30 parts of nitrogen. The 3 pairs of cylinders shewn in the Drawings
are reduced to 2, viz., the pairs of cylinders 1, 1, n, n¹. The safety valves are
dispensed with, as the apparatus is calculated to support a pressure of 18
atmospheres and ordinarily works at between 10 and 12 atmospheres. The air is
pumped from a drum having a capacity of from 200 to 300 litres, and consisting of
a sheet iron cylinder capable of supporting a pressure of two atmospheres. It is

page_text: closed at top and bottom by wire gauze screens of about 0.50 in diameter, between
which is disposed a septum made of silk coated with caoutchouc, as hereinafter
described. The drum is also provided with a pipe communicating with the pump
of the first apparatus, and as the drum is gradually exhausted by the action of the
pump the external air is diffused through the dialysing septa, one half of its
nitrogen being however retained, so that the air which enters the drum conse-
quently contains about 40 per cent. of oxygen (whereas atmospheric air contains
but 21 per cent.), this air already rich in oxygen being pumped into the apparatus
before described. By the above described arrangements large quantities of oxygen
at, say, 95 per cent. or higher can be obtained in a few minutes. The dialysing
drum herein described may be applied to forge bellows, blowers, &c., for supplying
air rich in oxygen, the employment of which would be of the greatest advantage
in metallurgy.
Figure 5 of the Drawings illustrates an arrangement of apparatus in which the
air is dialysed by means of an india rubber septum and utilized as above
described.
The working of the apparatus comprises three successive operations: 1st, pumping
the air; 2nd, dialysis of the oxygen by means of the septum ; 3rd, expulsion of
the nitrogeneous air. The air may be pumped by means of air pumps or steam
aspirators.
The Drawing shews the apparatus provided with steam jet aspirators, which are
much more economical in use than pumps. a is a bag made of silk coated with
caoutchouc and distended by an inner frame of galvanized iron. This bag is enclosed
in a sheet iron drum b, whose ends are formed of wire gauze c so as to permit of
the free circulation of air around the bag. d is an india rubber tube stiffened by
an internal spiral of wire connecting the bag with the aspirator e. The aspirator
is composed essentially of a series of cones f placed one behind the other with a
sufficient space between them. The steam jet introduced through pipe g into the first
cone induces a lateral current of air; the jet of steam and air in escaping froin
the first cone acts in the same way in the second cone, and so on in succession,
and by employing four or five cones a considerable volume of gas may be thus
exhausted and forced by means of a small steam jet. The aspirator c produces a
partial vacuum in bag a, and the external air is then caused to diffuse through the
rubber coated silk fabric, but as a larger proportion of oxygen than of nitrogen
passes through the septum the air drawn in will be richer in oxygen than atmos-
pheric air, and will contain about 40 per cent. of oxygen and 60 per cent. of
nitrogen. The steam and enriched air thus drawn in are forced by the steam jet
into the refrigerator coil h, where the steam condenses in drum i, while the gaseous
mixture escapes through the pipe k at the upper part of said drum into the second
apparatus 1. This consists of a sheet iron drum . hermetically closed, and
containing an india rubber bag m similar to a, and provided with two pipes n, o,
the one for the admission of the oxygenated air, and the other for the escape of
the gas in excess. The pipe o dips into a column of water p, the height of which
may be varied to regulate the pressure in l. The discharge by pipe o is of
considerable importance, as by it the non-dialysed nitrogen is carried through the
liquid p into the atmosphere. The bag m is exhausted by means of an aspirator e¹
exactly similar to e. The air dialysed by passing through the bag m contains
about 60 per cent. of oxygen and 40 per cent. of nitrogen, and may be conducted
by the pipe of the refrigerator into a third apparatus exactly similar to l
It is preferable to employ four apparatus in all, as shown, and on leaving the last
apparatus the air, then containing about 98 per cent. of oxygen, is stored in a gas
holder not shown in the Drawing.
After the 2nd dialysis the air containing about 60 per cent. of oxygen is
highly favorable for metallurgical operations; it will also quadruple the illuminating
power of a gas burner. Air containing about 60 per cent. of oxygen is that which
gives the best results, for lighting gas being relatively but slightly carburetted,
an equal volume of gas burns in pure oxygen with a flame, giving less light and

page_text: producing an excessively high temperature, whereas the combustion of gas in air
containing 60 per cent. of oxygen gives a light of maximum intensity without
unduly increasing the heat.
The dimensions and arrangement of the apparatus above described may be
varied without departing from the Invention.
I may here state that it has already been shown by the English chemist
Graham that membranes or porous bodies in the presence of gases produce
phenomena analogous to those which Du Trochet discovered as regards liquids ;
the porous divisions have the property of diffusing the gases with very unequal
rapidity whether in a vaccuum or in a gaseous atmosphere. Graham has indicated
that atmospheric air being separated from a vacuum chamber by a piece of silk
covered with black caoutchouc is dialysed by this septum. Although oxygen is
heavier than nitrogen it passes more readily through caoutchouc, so that the
dialysed gas contains more than 41 per cent of oxygen. This purely scientific
principle of Graham has not hitherto been commercially applied because such
an experiment does not assist in the industrial production of oxygen. The process
indicated by Graham only gives feeble quantities of dialysed gas in a length of
time relatively considerable. Consequently, and even with large septa and
apparatus, the production by this process pure and simple would not be practical
in a manufacturing or industrial sense. Graham has simply discovered one of the
properties of caoutchouc. Now the native caoutchouc (such as he employed and
indicated) possesses the property of diffusing gases only in a very slight degree,
while on the contrary by the process which forms part of the present Invention
this property of caoutchouc becomes very much increased.
Native caoutchouc is composed of two principal parts, the first is tenacious,
elastic, and very porous; the second, which is soft, adhesive, and pitchy is contained
in the pores of the first. This latter is much more soluble than the first in the
different solvents of caoutchouc, such as sulphide of carbon, ether, benzine, spirit of
turpentine, &c. It does not possess in any way the dialysing property indicated by
Graham, and besides, it retards the dialysis because it forms an obstruction to the
passage of the gases through the utricles of the elastic substance. It is also this
pitchy and semi-fluid material which produces in time under the influence of
oxygen, air, and light, the deterioration of the caoutchouc. It is evident from what
is above stated that the elimination of a certain quantity of this pitchy substance
is absolutely necessary. Therefore it is not native caoutchouc which is employed
according to this Invention for the manufacture of the septa, but only one of its
constituent parts.
The native caoutchouc used for the purposes of this Invention should not have
been previously dissolved, therefore sheets of caoutchouc of commerce obtained by
dissolving should be avoided; the spirit of turpentine employed in commerce for
dissolving caoutchouc becomes gradually resinified in the pores of the substance and
makes it pitchy. Normal caoutchouc alone cut into very thin sheets is employed
in the preparation; it is boiled for about two hours in water to remove fatty
matters adhering to it, and it is then dried in a heated chamber.
For the first operation I employ 100 parts of normal caoutchouc well dried,
500 parts of sulphide of carbon, and 40 parts of absolute alcohol. I leave them to
swell for about 48 hours at a mean temperature of 15 degrees to 20 degrees
centigrade.
At the end of 48 hours the mass considerably increased in bulk is treated in a
large bottle or vessel with a fresh quantity of sulphide of carbon and absolute
alcohol, say, 1,500 parts of sulphide and 100 parts of anhydrous alcohol. They
are left for about two hours, and then the whole is placed in a filter. The elastic
part of the caoutchouc remains on the filter in a gelatinous state, and the greater
portion of the pitchy substance is removed by the solvent, which may be afterwards
purified by distillation so that it may be used again. The substance remaining on
the filter is worked up and triturated by rollers or otherwise with 500 parts of
pure benzine to 100 parts of the substance. (The benzine is added by degrees to

page_text: combustion takes place. A current of dialysed air enters the burner at pipe L from
the dialysing apparatus before described. The burner is lighted by a small gas
jet placed above it. The sulphurous acid which is the product of this combustion
is conveyed into leaden chambers with dialysed air for conversion into sulphuric
acid, which may be used in the manufacture of pure oxygen, as before described.
The carbonate of lime residue which remains in the cylinder H is also utilized.
Having now described the nature of the said Invention as communicated to
me, and in what manner the same is to be performed, I declare that I claim,-
First. The process hereinbefore described of making or obtaining hydrogen
free from carbonic oxide and carbonic acid by submitting the gas or mixture of
gases produced by passing steam over charcoal, first to the action of sulphate of
lime and then to the action of carbonate of soda, substantially in the manner set
forth.
Second. The process bereinbefore described of making or obtaining oxygen by
first submitting a mixture of plaster (sulphate of lime) and river sand (silicic acid),
to the action of superheated steam in a retort, and then submitting the disengaged
mixture of oxygen and sulphurous acid to the action of a solution of caustic soda,
substantially in the manner set forth.
Third. The process herein before described of utilizing the sulphites of soda
obtained in the manufacture of oxygen in the manner herein explained, the said
process consisting in first treating the sulphites of soda so as to obtain acetate of
soda and sulphurous acid, and then treating the sulphurous acid so as to obtain
sulphuric acid or oxygen, all substantially as set forth.
Fourth. The process herein before described of making or obtaining air rich in
oxygen by forcing atmospheric air into and through apparatus constructed and
working substantially as described and represented in Figure 3, and containing water
with a proportion of glycerine or other substance which will increase the solvent
power of water for oxygen.
Fifth. The employment for the purpose of obtaining air rich in oxygen of
glycerine, spirits of turpentine, solution of phosphate, and carbonate of soda, alcohol,
and quenched charcoal, in the manner hereinbefore described, and in apparatas
constructed and working substantially in the manner explained with reference to
Figure 3.
Sixth. The employment for the dialysis of atmospheric air in the manner
described of septa forined of silk or other fabric or porous material coated or covered
with a substance obtained from normal or native caoutchouc, substantially as
herein before described.
Seventh. The construction and employment, substantially as herein before
described, of apparatus by which not only can a first dialysis be effected, producing
air with 30 to 40 per cent. of oxygen, but also a series of successive dialyses which
respectively enrich the oxygen to about the proportions of 39 per cent., 62 per
cent., 80 per cent., and 98 per cent., substantially as hereinbefore described.
Eighth. The several apparatus constructed and working substantially as herein-
before described and represented in the annexed Drawings, for making oxygen
and hydrogen for obtaining air rich in oxygen, and for obtaining and utilizing
bye products.
In witness whereof, I, the said Alexander Melville Clark, have hereunto eet
my hand and seal, this Fourth day of November, One thousand eight
1 1
A. M. CLARK. (L.S.)