Improvements in the Manufacture of Oxygen Gas.
Year: 1891

page_text: Date of Application, 31st July, 1891
Complete Specification Left, 29th Apr., 1892-Accepted, 11th June, 1892
PROVISIONAL SPECIFICATION.
Improvements in the Manufacture of Oxygen Gas.
We, GEORGE WEBB Junior of 13 Mill Street Lambeth Walk London S.E.
Engineer, and GEORGE HENRY RAYNER of 37 Chancery Lane London W.C.
Architect, do hereby declare the nature of this invention to be as follows:-
Our invention consists in improvements in the method and process for manu-
facturing oxygen gas from atmospheric air which may be referred to here as a
manganate of soda process. In a suitable constructed furnace we place a series of
tubes or retorts all fully charged with a chemical compound more specially referred
to hereafter, and these tubes have two inlets, one for air and one for steam and
two outlets one for nitrogen and the other for oxygen, air is blown into a vessel
containing a strong solution of caustic soda and thence into another vessel con-
taining sulphuric acid, and it now passes out into the retorts (which are heated to
a dull red heat by a suitably constructed furnace) the nitrogen outlet being open
and the steam inlet and oxygen outlet are closed. The chemical now absorbs the
oxygen, and the nitrogen escapes, and when the chemical compound has absorbed
as much oxygen as it can, the air supply is closed and the nitrogen outlet also
turned off, steam is now let into the retorts and the oxygen outlet opened-when
the oxygen gas passes off from the compound, through a purifier or scrubber, and
on into gas holders. When all the oxygen has been thrown off from the chemical
compound, the steam inlet and oxygen outlet are again closed and the process
repeated. We are aware that retorts charged with a chemical compound have
been used before in connection with this process but the whole process however has
never been a commercial success, probably on account of the fusing of the chemical
compound, at the required temperature, to rapidly absorb and throw off the
oxygen gas.
When the chemical compound has been prepared in connection with this process
which has not fused, it has been found unequal to the task of making oxygen gas
of any commercial value in the required time
This compound is therefore of vital importance to our invention and is made in
about the following proportious and manner, 16 ozs. or thereabouts of caustic soda
is dissolved in about forty ounces of hot water in a suitable vessel over a slow fire
and this is heated to boiling and thereto is added 16 ozs. or thereabouts of
manganese dioxide, 16 ozs. or thereabouts of soda manganate and the whole kept
well stirred, then is added one ounce or thereabouts of chlorade of potash the
whole is kept stirred until the moisture is entirely evaporated and the compound is
dry. This is then placed on a quick fire until the compound assumes a bright
redness and this heat to which the chemical is here subjected, is in excess to that
which it is afterwards subjected to in the retorts. The compound is then taken
out of the vessel and left to cool when it is broken up into small pieces about the
size of a walnut, and when nearly cold these are rolled in powdered manganese to
take up as much as will adhere to them. Although we have found it advantageous
to use the small proportion of chlorate of potash hereinbefore referred to, it does
not appear strictly essential to the success of the invention.
By means of our invention we can produce a gas containing between 85%

page_text: and 90% of pure oxygen at a cost of 2- to 3,- per 1,000 ft. a result never hitherto
obtained.
We can further enhance the purity of our gas by extracting some of the
remaining nitrogen by passing the gas through retorts containing baron, or carbon,
mixed with carbonate of soda, or any other known substance which has an affinity
for nitrogen while allowing the oxygen to go free.
Dated this 31st day of July 1891.
RAYNER & CASSELL,
37, Chancery Lane, Agents for Applicants.
COMPLETE SPECIFICATION.
Improvements in the Manufacture of Oxygen Gas.
We, GEORGE WEBB, Junior, of 13 Mill Street, Lambeth Walk, London S.E.,
Engineer, and GEORGE HENRY RAYNER, of 37 Chancery Lane, London, W.C.,
Architect, 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 :-
Our invention relates to improvements in the manufacture of oxygen gas from
atmospheric air according to the well known process carried on originally at Pantin
near Paris by Messrs. Tessié du Motay and Maréchal, and has for its object to
provide a compound for absorbing the oxygen from the air and subsequently
surrendering the same, which although being of a similar nature to that used
by the above mentioned chemists as well as by many others is subjected to such a
treatment as to render it suitable for carrying out successfully the process afore-
said, that is to say, as to prevent it from caking or fuzing whenever in the course
of constant usage it is accidentally raised to a higher temperature than is ordinarily
required for the operation.
To carry our invention into practice we use a furnace and numerous suitable
retorts arranged in such a manner that air and steam may be alternately supplied
at one end of the said retorts while the nitrogen freed and the oxygen produced
may be allowed to alternately escape at the other end, but as any similar apparatus
would answer the purpose we make no claim thereto, such apparatus being merely
composed of contrivances constantly used by chemists for general experimental
purposes and being well known under the before mentioned process.
The improved compound above referred to is prepared in the following manner:
16 ounces or thereabouts of caustic soda are dissolved in about 40 fluid ounces of
hot water and the mixture is heated to a temperature of about 100 centigrade in
a suitable vessel until the caustic soda has entirely dissolved. 16 ounces or there-
abouts of per oxide of manganese and 16 ounces of manganate of soda are now
added to the mixture which is diligently stirred under the action of heat until the
moisture is evaporated and the resulting mass is dry.
This mass is subsequently heated to a bright red or even white temperature
greatly in excess of that to which the compound will have to be subjected to during
the manufacture of the oxygen. The mass is then removed from the vessel and
broken up into small pieces about the size of a walnut. These pieces which are
slightly adhesive are afterwards rolled in powdered per oxide of manganese in
order that they may retain as much of the latter as will adhere thereto. This
operation is of great importance and its non performance may mar the success of
the operation, as the pieces are thereby prevented from coalescing and caking when
subjected to an excessive heat (such as white heat) in the retorts, which has hitherto
rendered useless the chemical compositions used for this purpose.
The compound produced in the manner just described is placed in a number of
retorts having each two inlets and two outlets. Air is blown into a wash bottle
containing a strong solution of soda whereby it is freed from the carbonic acid
which it contains and passes subsequently through another bottle containing

page_text: sulphuric acid and having for its object to free the air from any moisture which
may be present. The retorts are heated to a dull or crimson heat by a furnace of
any suitable construction, the air entering therein through one of its inlets, while
the corresponding outlet is left open. The compound will now absorb the oxygen
from the air, the nitrogen of which will be free to escape through the open outlet.
When the compound is saturated with oxygen the nitrogen outlet and the air inlet
are closed and steam is admitted through the other inlet when the oxygen
surrendered by the compound in the retort is allowed to pass through the other
outlet. When the whole of the oxygen yielded has passed off, the inlets and
outlets are reversely opened and closed and the first stage of the process repeated.
Having now particularly described and ascertained the nature of our said inven-
tion, and in what manner the same is to be performed, we declare that we
make no claim to the use of manganate of soda or to the use of caustic soda
in obtaining a preparation of manganate of soda, but what we claim is :-
(1) In the manufacture of oxygen from atmospheric air, the mode of treating
in the proportions given the compound used to absorb the oxygen from the air for
the purpose of subsequently surrendering the same, and coating the resulting
compound with peroxide of manganese whereby such compound is prevented from
coalescing or caking whenever subjected to too sudden or too excessive heat,
substantially as herein described.
Dated this 29th day of April 1892.
RAYNER & CASSELL,
37, Chancery Lane, London, W.C., Agents for the Applicants.