Improvements in Apparatus for Obtaining or Separating Oxygen from Atmospheric Air.
Year: 1891

page_text: Date of Application, 4th June, 1891
Complete Specification Left, 2nd Mar., 1892-Accepted, 9th Apr., 1892
PROVISIONAL SPECIFICATION.
Improvements in Apparatus for Obtaining or Separating Oxygen
from Atmospheric Air.
I, JAMES HOWARTH PARKINSON, of Stretford, in the County of Lancaster,
Gas Engineer, do hereby declare the nature of this invention to be as follows:-
This invention relates to apparatus for carrying out the process of separating
oxygen from atmospheric air by forcing or drawing purified air under pressure
through heated oxygen absorbing material and subsequently drawing off the
absorbed oxygen by reducing the pressure more particularly having regard to the
use of a permanganate for the purpose.
It is designed with the object of securing a continuous process and a continuous
How of oxygen and consists essentially in the construction and arrangement of
retorts, valves and regulating apparatus for the purpose as hereinafter more fully
described.
In carrying out the invention the atmosphere after being purified is passed into a
retort or chamber to be heated, thence to other retorts or chambers filled with a
porous spongy mass of permanganate which absorbs the oxygen and subsequently
delivers it up again, the oxygen being drawn off and collected in a suitable
receiver.
The atmospheric air is purified and freed from moisture in any well known
manner such as by being passed through suitable chambers charged with quick-
lime, sodium-hydrate, caustic potash, or other substance capable of absorbing
moisture, carbon dioxide, nitric acid, sulphurous acid, sulphuric acid, or other
impurities contained in the air.
The retort in which the purified air is heated and the retorts in which the
permanganate is heated are placed in a chamber or furnace and are supported.
therein on suitable girders to which they are bolted or otherwise attached. The
whole apparatus may be contained by an iron or steel or other casing supported on:
wheels or rollers for portability if desired. The retorts are preferably placed
vertical and heated with gaseous fuel.
Each retort is constructed with two chambers connected together at the bottom,.
a diaphragm or division plate extending down between them from the top nearly to
the bottom. Through each chamber of the retort one or more internal flues pass
turning off at the top. The heat thus comes in contact with a large heating surface
and helps to maintain an uniform temperature as far as possible throughout the
retorts and their contents. For this purpose also I place spirally or in other
position round the walls of the flue both in the flue and in the chamber of the retort
strengthening or conducting pieces preferably of diamond shape in cross section
which strengthen the retort and act for conducting and diffusing the heat or the
pieces may be extended within the chamber so as also to partly or wholly subdivide
the chamber of the retort. The surfaces of the retort and also of the flue through
which the heat is conducted may be either plain or corrugated as desired. The.
retort is closed by a lid held down by bolts.
One retort is utilized for the heating of the air before coming in contact with
the permanganate, another being utilized for absorbing the oxygen from the
atmosphere while in a third the oxygen is being liberated and drawn off from the
permanganate by which it had been previously absorbed. The number or capacity
of the retorts may be increased or decreased as may be desired.
The air is admitted through a perforated inlet rose to an air pump by which it is
pumped and delivered to an air compressor or second pump wherein it is compressed

page_text: to a considerable extent. From the air compressing pump the air passes through
pipes to the purifiers.
One retort is connected to the purifiers by a small pipe. The other two retorts
are connected to it by the pipes leading through a three way valve the valve
permits of only one pipe being open to the air heating retort at the same time or if
desired two valves may
be used one of which will be closed while the other is open.
The valve is connected to the piston rod of a cylinder the piston in which may be
actuated by steam, air, or other fluid or the valve might be worked by other
mechanical means. It is preferably made in the form of an equilibrium valve
with two faces and seatings raised and lowered by a screw first to one seat and then
to the other. Connected to it there is also fitted a spring or other buffer to take
up or compensate for any travel of the piston rod after the valve has come to its
seating.
The three way valve is moved by the piston rod to change the direction of the
current of air passing through the retorts. The oxygen is drawn off from the
retorts by a vacuum pump which reduces the pressure first in one and then in
the other whichever retort the three way valve is at the time closed to. On a pipe
leading from the retorts are placed two back pressure valves which allow the
nitrogen to pass out when there is an internal pressure in the retort but prevent
the entrance of any air when the pressure has been reduced in the retort by the
vacuum pump. On another pipe are two valves which act automatically according
to the pressure in the retorts to allow of the flow of the oxygen therefrom.
These valves are formed with a valve which is forced to its seat by the pressure
in the retort assisted by the spring (or weight) sufficiently strong or heavy to resist
the pressure remaining in the opposite retort which is acting upon the piston upon
the valve spindle working in a cylinder or chamber connected by a pipe either
to the opposite valve or to the interior of the other retort. When oxygen is being
drawn off from one retort there is a pressure in the other retort which acting
through the pipe raises the piston against a spring and with it the valve allowing
the oxygen to flow through. When the inlet valve is reversed and the pressure is
changed from one retort to the other retort the pressure and the spring (or weight)
closes the valve and the pressure in the other retort in a similar manner opens the
other valve. For the four valves may be substituted two three-way valves similar
to the inlet valve already described. In this case the valves might be operated by
a piston rod and only one pipe will be required between the valves and the retorts
instead of two pipes.
As the oxygen and other gas pass off through the pump they are delivered by a
pipe through a controlling valve which is adjusted to allow the gases to escape
when the pressure is such that the oxygen is mixed with nitrogen but when the
pressure is sufficiently reduced and pure or nearly pure oxygen is. coming off it is
allowed to go to a suitable receiver or receivers.
This valve is formed with two ways. or passages one leading to the retort or
chamber in which oxidation is taking place and the other leading to the retort or
chamber in which dioxidation is taking place with a third way or passage opening
from the retort or chamber containing purified air. The valve spindle carries two
valves and is raised and lowered by a screw. When the motion of the piston rod
raises the valve spindle one valve is forced to its seating and the other valve lifted
from its seating thus opening the passage in one direction when the motion of the
piston rod is reversed the other valve is forced to its seating closing the passage.
but opening the way or passage in the other direction.
Arrangements are also made so that should the other valve arrive at its seating
before the piston rod has completed its travel the remaining motion of the piston
rod is allowed for by a cushion or cushions such as a spring or springs or even an
air or vacuum cylinder or cylinders with piston therein.
This valve is provided with two valves on one spindle opening in opposite
directions the oxygen flows through one valve and the mixed gases through the
other valve. On the spindle is also placed a piston formed of a cup leather with

page_text: The
an india-rubber centre held between two metal plates adjusted by a nut.
piston works in a chamber or cylinder connected with the pressure in the retort by
a pipe. One valve is held to its seat by the pressure upon the piston assisted by
the spring which at the same time holds the other valve open. When the three-way
valve is reversed to change the direction of the flow of the incoming air the
pressure of oxygen and nitrogen from the retort in which oxygen has just been
absorbed forces up the piston and lifts one valve allowing the mixed gases to escape
through a nozzle. The gases are preferably cooled by passing through a gilled
or plain pipe surrounded by water or other cooling substance. As soon as the
pressure is reduced and the vacuum is sufficiently established in the retort the
reduction of pressure upon the piston closes one valve and opens the other through
which the rich oxygen passes to the gas holder.
The piston in the cylinder is actuated by a suitable fluid preferably compressed
air and the valve or valves in the valve chest are operated by the valve rod upon
which are two stop nuts or washers. A connecting rod is moved to and fro by a
crank pin on a disc which is geared by wheels or otherwise with the crank shaft of
the air pumps.
At each revolution of the disc the valve is moved to and fro by
the cross head of the connecting rod coming in contact with nuts on the valve rod.
The piston in the cylinder is provided with two piston rods. One rod actuates the
threeway valve and the other rod is connected to the second threeway valve when
used and to the valves which admit the gaseous fuel to the retort furnace. By this
arrangement the supply of the gaseous fuel is directed onto the retort or retorts
containing the permanganate yielding oxygen thus assisting the liberation of oxygen
by keeping up or elevating the temperature at the same time that dioxidation is
reducing the temperature. The retort or retorts in which the oxygen is being
absorbed has the heat cut off and cooled as far as practicable by the products of
combustion coming in contact with the retort or retorts containing permanganate
just immediately before its exit to the chimney or regenerators because such
absorption or oxidation is elevating the temperature.
The heated nitrogen as it escapes is conducted to a heat extractor or fuel
economiser through which the gaseous fuel supply pipes pass and the gaseous fuel
is thereby heated to a high temperature before entering the furnace.
The gaseous fuel is supplied to the furnace through a thermo-regulator by which
the amount of gas supplied is regulated by the heat of the furnace which is thus
maintained at a practically uniform temperature. The thermo-regulator is con-
structed with an annular chamber in which is placed a pipe with a number of
perforations extending over the greater part of its length. The pipe is open at
the bottom and sealed in the annular chamber by water or other liquid such as
mercury or oil according to the pressure required. The water or other liquid is
contained in a chamber connected to a retort or heating vessel. This retort (or
retorts if desirable) is filled with air or other gas and is placed in the retort
chamber beside the other retorts. The gaseous fuel is conveyed into either the
annular chamber or the perforated pipe preferably the latter and passes through
the perforations therein. The quantity of gas passing through is regulated by
the number of the perforations exposed. As the air in the retort expands with the
heat the liquid is driven from the chamber into the annular chamber so that as the
furnace becomes hotter the supply of fuel is gradually cut off by the rising head
of water in the annular chamber. Should auy cooling of the temperature of the
furnace occur the reverse action will take place in the thermo-regulator. A tap on
the connecting pipe serves to release the expanding gas or gases until the normal
temperature is obtained or for forcing in more air or gas to the retort.
In operation the retorts are filled with an oxygen absorbent material which when
sufficiently heated gives off oxygen and while at a temperature of dull redness.
(about 550° C.) in the presence of free oxygen under pressure will again combine
with or absorb the oxygen.
Atmospheric air is drawn in by the pump through the perforated inlet rose and
delivered to an air compressor by which it is forced into purifiers where it is freed

page_text: from moisture carbon-dioxide and other impurities. The purified air is then forced
into a retort where it is heated to a high temperature and from the retort passes
into the second retort. In the second retort the atmospheric air comes in contact
with the heated permanganate under considerable pressure. The permanganate
absorbs the oxygen and the nitrogen escapes either to the atmosphere or to a
receiver preferably first passing through a fuel economiser or heat extractor thus
imparting its heat to the gaseous fuel before being supplied to the furnace or it
could be utilized for heating the air instead of or in addition to the retort.
Whilst the air is being forced into the second retort the oxygen is being drawn of
from the permanganate in the third retort by the vacuum pump assisted as before
described by heat the oxygen passing to the gas holder. When the operation of
forcing in the air to the retort where oxygen is being absorbed and drawing off
oxygen from the other retort has been carried on for a sufficient length of time the
three-way valve is reversed by the piston rod and the direction of the current of
air changed so as to pass into the other retort the discharge valve acting auto-
matically or moved by the second piston rod to permit of the oxygen which has
been absorbed by the permanganate in the other retort being drawn off.
same time as the first piston rod reverses the three-way valve the movement of the
second piston rod also reverses the valves which admit the gascous fuel and air to
the furnace in order to supply. heat to the retort containing permanganate from
which the oxygen is being withdrawn.
At the
The process as herein described may be continued over and over again for a
lengthened period of time without renewal of the material the permanganate when
heated absorbing the oxygen from the air under pressure and giving off the oxygen
again when the pressure is reduced.
The apparatus herein described although primarily designed for use in the
separation of oxygen from nitrogen by means of permanganate will be also
applicable for use where other substances are used which will absorb and give off
oxygen under circumstances similar to those described.
Dated this 3rd day of June 1891
WM. P. THOMPSON & Co.,
6, Bank Street, Manchester, Patent Agents.
COMPLETE SPECIFICATION.
Improvements in Apparatus for Obtaining or Separating Oxygen
from Atmospheric Air.
I, JAMES HOWARTH PARKINSON, of Stretford, in the County of Lancaster, Gas
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 :-
This invention relates to the apparatus for carrying out the process of separating
oxygen from atmospheric air such as described in the Specification of my Patent
No. 14925 of 1890 and although the apparatus is shown, and partly described in
the Complete Specification thereof as being the best means known to me, at the
date of completing that Patent, of carrying the invention into effect-I have not
claimed any of the apparatus in that Patent for the reason that it was not designed
at the date of the application 149250 and the present application was entered
therefor before any publication had taken place.
The invention consists essentially in the construction and arrangement of retorts
valves and regulating apparatus wherein the air can be treated in contact with an
oxygen absorbent material and the oxygen subsequently drawn off therefrom.
The apparatus will be fully described with reference to the annexed drawings.
Fig. 1, general plan of apparatus or retorts in which the permanganate and

page_text: Fig. 11 plan of same..
In carrying out the invention the atmosphere after being purified is passed into
a retort or chamber to be heated, thence to other retorts or chambers filled with a
porous spongy mass of permanganate which absorbs the oxygen and subsequently
delivers it up again, the oxygen being drawn off and collected in a suitable
receiver.
The atmospheric air is purified and freed from moisture in any well known
manner such as by being passed through suitable chambers charged with quick
lime, sodium-hydrate, caustic potash, or other substance capable of absorbing
moisture, carbon dioxide, nitric-acid, sulphurous-acid, sulphuric acid, or other
impurities contained in the air.
The retort A in which the purified air is heated and the retorts B and C in
which the permanganate is heated are placed in a chamber or furnace D and are
supported therein by girders E to which they are bolted by the lugs e. The whole
apparatus may be contained by an iron or steel or other casing. The retorts are
preferably placed vertical and heated with gaseous fuel.
Each retort is constructed with two chambers connected together at the bottom,
a diaphragm or division plate F extending down between them from the top nearly
to the bottom. Through each amber of the retort an internal flue passes
turning off at the top or there may be more internal flues either parallel or placed
at any angle in the retort. The heat thus coming in contact with a large heating
surface helps to maintain an uniform temperature as far as possible throughout the
retorts and their contents. For this purpose also I place spirally or in other
position round the walls of the flue both in the flue and in the chamber of the
retort strengthening or conducting pieces preferably of diamond shape in cross
section which strengthen the retort and act for conducting and diffusing the heat
or the pieces may be extended within the chamber so as also to partly or wholly
subdivide the chamber of the retort. The surfaces of the retort as also of the
flue through which the heat is conducted may be either plain or corrugated as
desired. The retort is closed by a lid F¹ held down by bolts or studs.
The retorts A, B and C are set in the retort chamber D as shown in the general
plan in Fig. 1 the retort A being utilised for the heating of the air before coming
in contact with the permanganate, the retort B being utilised for absorbing the
oxygen from the atmosphere while in the retort C the oxygen is being liberated
and drawn off from the permanganate by which it had been previously absorbed!
The number or capacity of the retorts A, B and C may be increased or decreased:
if desired.
:
The air is admitted through a perforated inlet rose G and pipe g to the air!
pump H by which it is pumped and delivered to the air compressor or second-
pump I, through the pipe wherein it is compressed. From the air compressing
pump I, the air passes through the pipes j and k to the purifiers J and K.

page_text: The air compressors or pumps H. and I and the purifiers J and K may be of any
ordinary or convenient form and may be placed in any suitable position with con-
necting pipes such as j k and 7 through which the air passes.
The retort A is connected to the purifiers J and K by the pipe a. The retort A
is connected to the retort B by the pipe band to the retort C by the pipe c leading
through a three way valve M to the pipe a' the valve permits of only one pipe
being open to the retort A at the same time (or if desired two valves may be used
one of which will be closed while the other is open). The valve M is connected to
the piston rod o of a cylinder O, the piston in which may be actuated by steam
air or other fluid or the valve M might be worked by other mechanical means. The
valve M as shewn in Figs. 10 and 11 is preferably made in the form of an
equilibrium valve with two facings m m and seatings raised and lowered by a
screw m first to one seat and then to the other. It is also fitted with a spring
or other buffer attached to the lever to take up or compensate for any travel of
the piston rod o after the valve has come to its seating.
The threeway valve M is moved by the piston rod o to change the direction of
the current of air passing through the retorts B and C. The retort B is not
directly connected to the retort but each have a common pipe P and a pipe Q
leading from them, the pipe P delivering nitrogen from one retort when the pipe Q
is delivering oxygen from the other retort. The oxygen is drawn off from the
retorts by the vacuum pump R which reduces the pressure first in one and then in
the other of the retorts B and C, whichever retort the valve M is at the time
closed to. On the pipe P there are placed two back pressure valves S S¹ which
allow the nitrogen to pass out through the valve S from the retort B and the
valve S' from the retort C when there is an internal pressure in the retort but
prevent the entrance of any air when the pressure has been reduced in the retort
by the vacuum pump R. On the pipe are also two valves T T which act
automatically according to the pressure in the retorts to allow of the flow of the
oxygen therefrom.
The valves T T are shown in detail Fig. 6 the valve is forced to its seat by
the pressure in the retort B assisted by the spring (or weight) sufficiently
strong or heavy to resist the pressure remaining (or being reduced) in the opposite
retort C which is acting upon the piston t working in a cylinder or chamber
connected by the pipe either to the opposite valve T or to the interior of the
retort C. When oxygen is being drawn off from the retort B there is a pressure
in the retort which acting through the pipe raises the piston against the
spring and with it the valve t allowing the oxygen to flow through. When the
inlet valve is reversed and the pressure is changed from the retort C to the retort. B
the reduced pressure or partial vacuum and the spring (or weight) closes the
valve and the pressure in the retort B in a similar manner opens the valve T¹.
For the four valves S and S T and T¹ may be substituted two threeway valves
similar to valve M Fig. 1. In this case the valves might be operated by the
rod o and only one pipe P Fig. 1 will be required between the valves and the
retorts instead of the pipes P and Q.
As the oxygen and other gas pass off through the pump R they are delivered
by the pipe through a separating valve U which is adjusted to allow the gases to
escape when the pressure is such that the oxygen is mixed with nitrogen but when
the pressure is sufficiently reduced and pure or nearly pure oxygen is coming off it.
is allowed to go to a suitable receiver or receivers.
The valve U is shown in detail in Figs. 7 and 8 and, is provided with two
valves UU on one spindle opening in opposite directions, the oxygen flows
through the valve U and the mixed gases through the valve U. On the
spindle u is also placed a piston u' formed of a cup leather with an indiarubber
centre held between two metal plates adjusted by a nut. The piston works
in a chamber or cylinder connected with the pipe Q by a pipe The
valve U is held to its seat by the pressure upon the piston assisted by the
spring which, at the same time holds the valve. U open. When the valve M

page_text: is reversed to change the direction of the flow of the incoming air the pressure
of oxygen and nitrogen from the retort in which oxygen has just been absorbed
forces up the piston and lifts the valve U" allowing the mixed gases to
escape through the nozzle 1. The gases as they pass through the pipe uli
are preferably cooled by passing through a gilled or plain pipe surrounded by
water or other cooling substance. As soon as the pressure is reduced and the
vacuum is sufficiently established in the retort the vacuum upon the piston
closes the valve U and opens, the valve U through which the rich oxygen:
passes through the pipe to the gas holder.
The piston in the cylinder O is actuated by a suitable fluid preferably com-
pressed air and the valve or valves in the valve chest Z are operated by the
valve rod upon which are two stop nuts or washers.
1.
The rod o
A connecting
rod V is moved to and fro by a crank pin on a disc V' which is geared by
wheels or otherwise with the crank shaft H of the air pumps. At each revolu-
tion of the disc V₁ the valve is moved to and fro by the cross head of the
connecting rod V coming in contact with the nuts on the valve rod
The piston in the cylinder O is provided with two piston rods o o¹.
actuates the valve M and the rod o' is connected to the valves which admit the
gaseous fuel to the retort furnace. By this arrangement the supply of the
gaseous fuel is directed onto the retort or retorts containing the permanganate
yielding oxygen thus assisting the liberation of oxygen by keeping up or elevating
the temperature at the same time that deoxidation is reducing the temperature.
The retort or retorts in which the oxygen is being absorbed has the heat cut off
and cooled as far as practicable by the products of combustion coming in contact
with the retort or retorts containing permanganate just immediately before its exit
to the chimney or regenerators because such absorption or oxidation is elevating
the temperature.
The heated nitrogen as it escapes through the pipe P is conducted to the heat
extractor or fuel economiser P¹ through which the gaseous fuel supply pipes pass
and the gaseous fuel is thereby heated to a high temperature before entering the
furnace.
The gaseous fuel is supplied to the furnace through a thermo-regulator W by
which the amount of gas supplied is regulated by the heat of the furnace which is
thus maintained at a practically uniform temperature. The thermo-regulator W
is shown in detail in Fig. 9. In an annular chamber W is placed a pipe w with a
number of perforations extending over the greater part of its length. The pipe w
is open at the bottom and sealed in the annular chamber W by water or other
liquid such as mercury or oil according to the pressure required. The water or
other liquid is contained in a chamber w¹ connected to a retort or heating vessel wo"
by the pipe 11. The retort w (or retorts if desirable) is filled with air or other
gas and is placed in the retort chamber beside the retorts A, B and C. The
gaseous fuel is conveyed into either the annular chamber W or the perforated
pipe o preferably the latter and passes through the perforations therein. The
quantity of gas passing through is regulated by the number of the perforations
exposed. As the air in the retort w expands with the heat the liquid is driven
from the chamber wl into the annular chamber W₁ so that as the furnace becomes
hotter the supply of fuel is gradually cut off by the rising head of water in the
annular chamber W. Should any cooling of the temperature of the furnace occur
the reverse action will take place in the thermo-regulator.. The tap won the
pipe
serves to release the expanding gas or gases until the normal temperature
is obtained or for forcing in more air or gas to the retort w".
In operation the retorts B and C are filled with an oxygen absorbing material
and atmospheric air is drawn in by the pump H through the perforated inlet G and
delivered to the compressor I by which it is forced into the purifiers J and K
where it is practically freed from moisture carbon dioxide and other impurities.
The purified air is then forced into the retort A where it is heated to a high
temperature and from the retort A passes into the retort B through the pipe b. In

page_text: the retort B the atmospheric air comes in contact with the heated permanganate
under pressure. The permanganate absorbs the oxygen and the nitrogen escapes
through the pipe P and back pressure valve S either to the atmosphere or to a
receiver preferably first passing through a fuel economiser or heat extractor P thus
imparting its heat to the gascous fuel before being supplied to the furnace or it
could be utilized for heating the air instead of or in addition to the retort A.
Whilst the air is being forced into the retort B the oxygen is being drawn off
from the permanganate in the retort. C by the vacuum pump R assisted as before
described by heat the oxygen passing away through the pipe Q and valves T or
their substitute as before referred to and the valves U and pipe (which act in the
manner herein before described) to the gas holder. When the operation of forcing
in the air to the retort B where oxygen is being absorbed and drawing off oxygen
from the retort C has been carried on for a sufficient length of time the valve M is
reversed by the piston rod o and the direction of the current of air changed so-as
to pass into the retort C the valves T T' and U acting automatically to permit of
the oxygen which has been absorbed by the permanganate in the retort B being
drawn off. At the same time as the piston rod o reverses the valve M the move-
ment of the piston rod o¹ reverses the valves which admit the gaseous fuel and air
to the furnace in order to supply heat to the retort containing permanganate from
which the oxygen is being withdrawn.
The piston in the cylinder O is actuated by compressed air or steam and the
valves are operated by a connecting rod V from the disc V', ell being adjustable
nuts on the valve rode with which the cross head comes in contact.
The apparatus herein described although primarily designed for use in the
separation of oxygen from nitrogen by means of permanganate will be also
applicable for use where other substances are used which will absorb and give off
oxygen under circumstances similar to those described.
Having now particularly described and ascertained the nature of the said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is :-
1. In apparatus for separating oxygen from atmospheric air a retort of U shape,
with flues to convey the heated products through the centre of the material and
increase the heating surface substantially as described.
2. In apparatus for separating oxygen from atmospheric air a three way valve
for directing the flow or passage of the air to the retorts constructed substantially
as described with reference to Figs. 10 and 11.
3. In apparatus for separating oxygen from atmospheric air a valve for drawing
off the oxygen constructed and arranged substantially as described and shown with
reference to Fig. 6 whereby the opening and closing thereof for the passage of
oxygen is automatically controlled by the pressure in the retorts with which it is
connected.
4. In apparatus for separating oxygen from atmospheric air a valve by which the
nitrogen and impure oxygen is allowed to escape constructed and arranged substan-
tially as described and shown with reference to Figs. 7 and 8 by which the gas is
automatically allowed to escape when the pressure is such that the oxygen will be
mixed with nitrogen.
5. A thermo-regulator for regulating the temperature of retorts in oxygen
separating apparatus constructed and arranged substantially as described.
6. Apparatus for separating oxygen from atmospheric air having the several
parts constructed and arranged (with or without the thermo regulator shown in
Fig. 9) substantially as and for the purposes described.
Dated this 1st day of March 1892
WM. P. THOMPSON & Co.,
Manchester, Liverpool, and London, Patent Agents.