Improvements in and connected with the Manufacture of Oxygen.
Year: 1895

page_text: Date of Application (in United Kingdom), 22nd July, 1895
Complete Specification Left, 22nd July, 1895-Accepted, 31st Aug., 1895
Improvements in and connected with the Manufacture of Oxygen.
I, HENRI LOUIS ARMAND LAPOINTE (signing as H. Lapointe) of 10 Rue
Mansart, Paris, Civil Engineer, 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 :-
In the manufacture of oxygen say by oxydizing and deoxydizing alkaline
manganates by alternate currents of air and steam there has heretofore been
considerable difficulty both in securing a satisfactory form of apparatus and a pure
resulting product. In regard to the apparatus some of the difficulties may be
stated as consisting in maintaining economically the necessary high temperature for
the retorts which must be capable of resisting considerable pressure, and the joints
and connections to which require to be perfectly tight, further difficulties being in
securing a proper circulation of the air and steam through and in intimate contact
with the materials contained in the retorts. The main difficulty in regard to the
purity of the resultant oxygen has arisen from there being a certain amount of air
in the retorts and connections when the steam has been admitted and such air has
been carried over with the oxygen which consequently enters the holder or receiver
with a certain amount of nitrogen which in this case may be considered as an
impurity.
By the aid of this invention the above difficulties are avoided and a practically
pure resultant product obtained, the process being in all essential respects a
continuous and automatic one.
The alkaline manganate employed may consist of manganate of soda which is
prepared by heating to a dull red heat in a current of hot air a mixture of bi-oxide
of manganese and soda, the manganate of soda so produced when submitted to the
action of a stream of superheated steam yielding its oxygen, and returning to its
original form of bi-oxide of manganese and soda.
This reaction is well known, but as stated previously difficulty has been found
in carrying the process out in a satisfactory commercial manner.
To clearly explain my invention, reference is made to the accompanying drawings
in which :-
Fig. 1 is a front elevation showing an arrangement of retorts.
Fig. 2 is a plan.
Fig. 3 is a side elevation.
Figs. 4 and 5 are respectively a front elevation and plan drawn in a manner to
acilitate the understanding of the arrangement of the retorts and connections in
he previous figures.
Fig. 6 is a diagram of a retort and connections given for the purpose of an
explanation which is hereafter made.

page_text: Fig. 9 is a cross section of Fig. 8 on line x, x.
Fig. 10 is an elevation of the cover of the retorts.
Fig. 11 is a cross section of same on line z.
Fig. 12 is a front elevation of the retorts with the cover removed.
Figs. 13 and 14 are sectional views on an enlarged scale of the inlet distribution
box for the fluids, Fig. 14 being a cross section on the line x y.
Fig. 15 is a sectional view of the outlet distribution box, and
Figs. 16 and 17 are respectively a sectional elevation and plan of a lamp or
burner.
Referring first to Fig. 6, C may be taken as a retort containing a charge as
before described, a being an air inlet, a a nitrogen or air outlet, va steam inlet,
and-v-a-steam outlet. During the oxidation period the cocks a a' are open and the
two cocks v and v are shut. Let us suppose now that the oxidizing period is
finished and that the two cocks a and a' are shut. The retort C will be full of
air or nitrogen. If the two cocks and are now opened the steam will go
into the retort and pass through same taking out the oxygen yielded by the
manganate of soda and the nitrogen or air.
As the amount of oxygen produced is not proportionate to the duration of the
(successive) series or "cycles" of operations but is proportionate to their number
it would seem to be advantageous to shorten their duration so that their number
might be augmented. But in that case the quantity of nitrogen or air admitted
would also go on increasing and the product would be so much the less pure as the
duration of the said "cycles" of operations was shorter. It will therefore be seen
that what is really desirable is that the air or nitrogen should be removed
discharged outside the retort.
or
The method which I employ in order to get rid of the air or nitrogen which fills
the retorts after the oxydation period is to produce a vacuum with an ordinary
pneumatic pump, being careful to cool down the gases before they pass through
said pump, the more perfect the vacuum the purer will be the oxygen obtained.
The vacuum offers moreover, this great advantage that by its use, the reactions
take place more quickly and better for two reasons:-
1st. The dissociating tendency of the manganese increases as the pressure
becomes less. The de-oxidation is thus much more easy to obtain when the
pressure in the retort is less.
2nd. The vacuum acting in the retort by the same opening as the air, it follows
that the particles of the charge are subjected alternately to two motions in contrary
directions, so that they are in a manner turned round, and offer consequently new
surfaces of action to the fluids. From this it follows that the oxidation takes place
quicker and with greater energy.
The employing of a vacuum to exhaust the air or nitrogen which is in the retort,
and to facilitate and increase the speed of the reactions is I believe an entirely new
application in the extraction of oxygen from the air by the method previously
stated.
The complete cycle of the operation includes: (a) oxidation (b) vacuum
(c) de-oxidation. Each of these three phases takes place at equal intervals of time
in each of the retorts or groups of retorts. And, in order to obtain a continuous
production of oxygen, the apparatus has three retorts or groups of retorts in contra-
distinction to the previous process which had only two phases: oxidation and
de-oxidation, and which had consequently only two retorts or set of retorts.
Referring to Figs. 1, 2, 3, 4, and 5, in a furnace F preferably heated by a gas
producer, are fitted 3 retorts A1, A2, A³ or sets of retorts. These retorts are
composed of a head A (Figs. 7, 8, 12) having a cover, said head having secured
three cylindrical chambers or retorts a, a, a. The cover is provided with two
openings E and S, the first one being an inlet opening and the second an outlet for
the fluids. Two pipes T, T', are fitted opposite these holes. These pipes are

page_text: fitted into the thickness of the front wall of the furnace. They serve to hold on
their front faces the distribution boxes. On the inlet hole and inside the head of
the retort is fitted a special part having three connections which are attached to
the perforated iron pipes t t t. It is by these pipes that the steam and air pass in
alternately. These fluids thus come into intimate contact with the charge oxydize.
or de-oxidize it as the case may be and pass away by the opening S and pipe T¹.
This shape of retorts offers the following advantages: Great heating surface for
a small volume and a reduced number of joints, great resistance to the pressure,
it allows moreover of placing the retort entirely inside the furnace and thus
prevents any outside cooling action. This shape also allows of the fluids passing
in by a central pipe, and moreover obviates the necessity of a metallic door to the
front of the furnace.
It will be seen that the circulation of air and steam always takes place in the
same way. They.come in by the opening E and go out by S. During the stage
of getting the vacuum, on the contrary, the nitrogen being drawn by the opening E,
the circulation takes place in the contrary way.
A compressor pump supplies a continuous stream of air under pressure. This
pressure during the oxidation period has for effect to insure a better contact
between the air and the charge. In order to maintain the air under pressure in.
the retorts, the nitrogen escape pipe D, which is the same for the three
retorts A1, A2, A3, carries expansion valve R which regulates the pressure to that
which is necessary...
The air on leaving the compressor, passes first into purifying boxes containing
lime and soda where its moisture and carbonic acid are withdrawn, from thence
it goes to the superheater, and is admitted to the retorts only when its temperature
is suitable for the reaction. and eventually passes into each retort, by turns, by the
pipe B.
A steam boiler supplies a continuous current of steam.
This steam is super-
heated too before being admitted in the retorts and passes in to the retorts, through
the pipe V..
Finally a pneumatic pump which works continuously, operates to produce a
vacuum in the retorts by the pipe v, thus there are three retorts or sets of retorts
fitted in a furnace and heated to a convenient heat, three currents, air, steam, and
vacuum the two first ones being heated to a suitable temperature. The quantity of
air and steam sent in, and of nitrogen taken off are such that the two phases will
last exactly the same time, that is to say, when the oxidation period is finished
in one retort A', for instance, the vacuum is created in the retort A2 and the
de-oxidation has just taken place in the retort A³. And at a proper time, by the
operation of the distribution valves, the three phases in each of the three
retorts, A¹, A², A³, are shifted. After this operation, the vacuum is to be obtained
in the retort A', the de-oxidation in A2 and the oxidation in A³. When this new
phase has taken place a further operation of the distribution valves again takes
place so that the de-oxidation will take place in A', oxidation in A2 and the vacuum
in A. And the phases will thus continue indefinitely, in the same order, at equal
intervals of time yielding a continuous stream of oxygen which comes out, by
turns, of each of the retorts A³ A² A³.
With regard to the distributing mechanism which effects this operation it bas
been previously stated that opposite the openings E and S on the retort cover are
the pipes T and T¹, each of these pipes holding one distribution box.
3
In the inlet box M (Figs. 13 and 14) the distribution of fluids and shutting of
retort openings is done by means of spindle valves. The general principle which
as directed their design is that: at any time the pressure which holds the valve to
ts box must always be greater than the one which tries to lift it.
In order to understand the necessity for the valves, answering this condition, it
hould be remembered that during a complete cycle, every retort is, at first, during
he oxidation period under pressure this pressure being always greater than the
tmospheric one; second, during the vacuum period, during which the pressure in

page_text: let box) are opened. The steam coming by the pipe V flows now into the retort
ollowing the same path as the air did previously and de-oxidizes the manganate.
The mixture of steam and oxygen leaves by the outlet box going to the condenser
y the pipe O and from there to the holder.
;
During this phase, the steam pressure makes the vacuum valves (3 and 4) hold on
heir seats but it acts to raise the air inlet valves 1 and 2 and the nitrogen outlet.
alves 9 and 10 (outlet box). But, the air pressure during the oxidizing period is:
higher than the steam pressure during the de-oxidizing one. Consequently the
valves 1 and 2 are subjected on their upper faces to a greater strain than on their
As for the outlet nitrogen or air
under ones, so that they will hold to their seats.
valves 9 and 10 as already stated they have above them a counter pressure:
(maintained by the special valve R) which is superior to the pressure of the steam.
So these valves will hold to their seats too.
In all the actions which have just been described, the weight of the valves and
spindles h and the action of springs r connected to the bottom of spindles add their
own action to those of the fluids.
For the other retorts the steam pressure holds the valves on the inlet side on.
their seats and ensures the tightness of same.
Some pieces of wire gauze t' t't' and t, t, t, (Figs. 13, 14 and 15) are put between
the valves in order to stop the dust and dirt which might be driven off by the
draught of the fluids. For the purpose of opening and closing the valves at
the right time all the spindles h are carried down at their ends to about the level of a
horizontal shaft d which runs parallel with the front of the furnace. This shaft d
carries as many cams L L L as there are valves. These cams are fitted in such a
manner that when the shaft turns round, they lift through the medium of levers Z
When the shaft turns
(Figs. 1 and 3) the spindles thus opening the valves.
round again, the cams leave the levers Z and the valves shut by their own weight
and by the action of springs r. The time of a cycle being determined it will
be seen that it is sufficient to turn the shaft round, at regular intervals of time, in
order to open and shut the valves and thus send by turns, the air, the steam and
produce the vacuum in each retort
The cam shaft turns round a third of a turn at regular intervals of time. The
steam is admitted at these intervals by a cock P (Fig. 3) into the steam
cylinders K K. The pistons of these cylinders being raised they operate by
means of the rods p, q, and the catch f which operates in turn a notched disc f,.
the gear wheels g, g', the latter being on the shaft d which turns round one third.
The steam becoming condensed in the cylinders (while at the same time a drain
cock is automatically opened by the steam piston itself when at the top end of its.
stroke) and the steam cock P being shut the steam pistons descend ready for
another stroke. In this down motion of the pistons the shaft d is not moved on
account of the construction of the catch fand notched disc fl.
The motion of the shaft however can be obtained in many different ways.
In order to be able to follow with certainty and continuously the reactions and
thus to be able to decide the time of the cycles, I use a special lamp or burner.
This lamp (Figs. 16 and 17) is composed of a platinum cap c maintained at a red
heat by a stream of oil gas which flows by the pipe W. The intensity of this
A chamber w¹ surrounds the
stream may be regulated by means of the valve w.
This
pipe W, said chamber being regulated by turning the coned head w².
chamber may be put in communication with the inside of the retorts or any other
receiver, the gas, thus admitted in the flame of the oil gas will according to its
nature increase or lessen the incandescence of the platinum cap. As the nature of
the gas in the retorts is modified at every moment following closely the reaction it.
ill be sufficient to have the chamber w of the lamp communicating with the
Ne of a retort in order that the lamp may follow and indicate the reactions
on inside said retorts.
oper frame holds some blue glasses n of different shades which enable the

page_text: :
The complete apparatus has several of these lamps or burners so fitted as to
communicate one with each of the retorts, the others with the gas holder, the air
and steam superheaters. These last lamps give fixed indications which are used
as standards to compare the varying indications according with the reactions of the
three first ones.
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, I declare that what I
claim is :-
1. In the production of oxygen the employment of a vacuum for extracting the
air or nitrogen from the retorts, substantially as described.
-2: In the production of oxygen the employment of three retorts or sets of
retorts and mechanism whereby the process of oxidation, exhaustion of air or
nitrogen and deoxidation may be carried on automatically, substantially as
described.
3. The construction and arrangement of retorts substantially as and for the
purpose described and illustrated in Figs. 7 to 12.
4. In the production of oxygen the employment of air under pressure during the
oxidation period and the devices for enabling it to be so maintained substantially as
and for the purpose described.
5. In the production of oxygen, the employment in the retort or retorts of a
vacuum acting in the opposite direction to the pressure of air in the retort, whereby
the charge is subjected to a disturbing action, substantially as described.
6. The construction and arrangement of the distributing boxes and valves,
substantially as and for the purpose described and illustrated in Figs. 13, 14
and 15.
7. The construction and arrangement of parts for operating the valves,
substantially as and for the purpose described.
8. In valves constructed substantially as described the employment of pieces of
wire gauze or a filtering medium substantially as and for the purpose described.
9. In the production of oxygen the employment of a lamp for indicating the
reactions taking place in the retort such lamp operating by varying the
incandescence of a part of same, substantially as described.
'
10. The method or process for the production of oxygen substantially as
described.
11. The general arrangement and construction of the retorts and connections for
carrying on a continuous process for the manufacture of oxygen, substantially as
described and illustrated.
Dated the 22nd day of July 1895.
PHILIP M. JUSTICE,
55 & 56 Chancery Lane, London, Chartered Patent Agent,
For the Applicant.