Improvements in the Separation and Obtainment of the Constituents of Gaseous Mechanical Mixtures.
Year: 1892

page_text: Date of Application, 5th Mar., 1892
Complete Specification Left, 5th uec., 1892-Accepted, 4th Mar., 1893
PROVISIONAL SPECIFICATION.
Improvements in the Separation and Obtainment of the Constituents
of Gaseous Mechanical Mixtures.
I JAMES HOWARTH PARKINSON Gas Engineer Stretford Lancashire do hereby
declare the nature of this invention to be as follows:-
Hitherto fluids have generally been obtained for purposes required either by
chemical combination or decomposition.
My improvement consist in separating the admixture of mechanically mixed
fluids and as the atmosphere consists of a mechanical mixture (and perhaps the
most difficult to separate) I will take this as an example and explain my procedure
somewhat in detail, although it will readily be seen that my invention is applicable
to other fluids which might advantageously be separated and which have now to be
accomplished chemically or allowed to waste; for example carbon dioxide which is
evolved largely through the decomposition of carbonates as in the burning of
limestone (CaCO3) or in the ordinary chemical combinations of nearly all hydro-
carbons with air or oxygen, these are bye-products and are generally allowed to go
to waste and which contaminate the atmosphere.
In carrying out my invention I take advantage of the different points of lique-
faction of the fluids composing the mixture such as temperatures or pressures or
both (and which said mixture we will now assume to be the atmosphere),,and also
in the difference in the specific gravity if any of the fluid before or after liquefaction,
generally the latter, or in the magnetic property of those fluids possessing such, as
oxygen or ozone; or a combination of such liquefaction, specific gravity, or magnetic
property may be employed.
The atmospheric air to be separated I cause to pass through a chamber surrounded
by a vessel containing ether, alcohol or sulphur-dioxide caused to vaporize by a
pump regulated in quantity & also regulated by barometric or other pressure to
give out sufficient cold to liquefy and yet not solidify the H,O contained, in
atmospheric air. The remaining gases I now pass if necessary through other
chambers each surrounded by vessels containing fluids of lower boiling point than
its preceding one such as CO, or N,O, caused to boil or vaporize in vacuo so, as to
liquefy and thus permit the separation of any fluids other than nitrogen and oxygen
contained in the atmospheric air.
These remaining gases nitrogen and oxygen being somewhat cooled I cause to
pass through three separate chambers each surrounded by separate vessels, as above
described, the temperature of each decreasing (as subsequently described) until, in
the last one the above oxygen or nitrogen liquefies and passes to a suitable chamber
when gravitation and magnetism assists in separating the one from the other, should
they both liquefy the same holds good.
And I could further assist their separation by causing them to revolve rapidly
when the fluid of least specific gravity will be the uppermost layer and the one of
greatest specific gravity will be at the bottom and if I now attract magnetically
the oxygen in the desired direction 1 shall assist its separation.
To take the now partially separated fluid where desired it is only necessary. to
introduce a pipe to convey the uppermost layer and another pipe to convey the
lowest layer of fluid when the momentive force of the rapidly revolving fluid will
drive the liquid a reasonable distance where desired.
Now within the final vessel surrounding the final chamber I would circulate
atmospheric air in a liquid state, and caused to boil in vucno by a pump this would
insure the final chamber being extremely cold. Within the previous vessel
surrounding the previous chamber I cause to circulate the fluid nitrogen which has
been separated as above described thus cooling down the purified atmosphere almost

page_text: to liquefaction at the expense of the so-called waste nitrogen.
The oxygen
previously separated I would also pass through the remaining vessel where its cold
is absorbed as previously explained in reference to the waste nitrogen. The thus
separated fluid oxygen & nitrogen are now directed where desired.
Dated this 4th day of March 1892.
JAMES HOWARTH PARKINSON.
COMPLETE SPECIFICATION.
..Improvements in the Separation and Obtainment of the Constituents
of Gaseous Mechanical Mixtures.
I, JAMES HOWARTH PARKINSON, of Stretford, in the County of Lancashire,
England, 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 ascer
tained in and by the following statement :-
Heretofore it has been usual to obtain fluids as for example oxygen, hydrogen,
nitrous oxide and carbon dioxide, in a pure or practically pure state, by costly
chemical processes.
Now this invention has for its object to obtain fluids of various kinds in a pure
or practically pure state, and in a rapid and economical manner, from gaseous
mixtures that exist in nature or which can be readily and cheaply produced as for
examples, oxygen from air; hydrogen from water-gas; nitrous oxide from a
mixture of chlorine, nitrous and nitric oxides and nitrogen; and carbon-dioxide
'from the gaseous products escaping from lime kilns and from furnaces in which
carbonaceous fuels are burnt, and which are usually waste bye-products.
For this purpose I take advantage of the different points of liquefaction, or the
different boiling points after such liquefaction of the constituents of the gaseous
mixture, or of the difference in density or specific gravity of the liquefied con-
stituents, or of the different magnetic properties thereof.
In carrying out my invention I cause the gaseous mixture by reduction of
temperature, or by pressure, or by both these means combined, to assume a
condition in which the desired constituent or constituents will become liquefied and
thus separated from the other gas or gases with which it or they were mixed, the
liquefaction in the case of its being desired to obtain two or more of the con-
stituents separately being usually effected in successive stages corresponding to the
different liquefying points of the said constituent gases.
To separate oxygen from nitrogen, which gases are probably the most difficult
of all gases to separate, by reduction of temperature I subject the mixture thereof
to a very low temperature corresponding to the liquefying point of one or both of
the gases, with or without pressure, and then separate them from each other by
centrifugal force, or specific gravity, or by magnetic attraction, or by allowing the
nitrogen to evaporate from the oxygen, or by two or all of these means combined.
The reduction of temperature necessary for the above purpose is obtained by
causing a highly volatile liquid to evaporate in an attenuated atmosphere produced
by drawing off the gas or vapor as soon as formed, such gas or vapor being
.reconverted into the liquid state by pressure, and by cold produced by the
evaporation of another volatile liquid having a higher boiling point, these operations
being repeated any suitable number of times and commencing preferably with a
volatile compound that can be easily liquefied. Suitable volatile compounds for
this latter purpose are for examples sulphuric ether, sulphur dioxide, chloroform,
or ammonia, or any other volatile substance the price of which is not prohibitive;
which will not attack the baser metals; and whose liquefying point is easily
attained say by pressure in conjunction with the cooling action of water at the
ordinary temperature of the atmosphere. Such liquids, though their first cost may
be rather great, can be used over and over again without much loss, their function
being simply that of heat carriers.
"a

page_text: to describe the method of separating oxygen and nitrogen and win for this purpose
refer to the accompanying drawings, in which,
Fig. 1 is a sectional elevation; and
Fig. 1A a plan, illustrating diagrammatically apparatus suitable for this purpose.
Figs. 2 to 13 inclusive illustrate apparatus suitable for carrying out my invention
on a practical scale,
Fig. 2 being a diagrammatic view showing the general arrangement of the
apparatus employed.
Figs. 3 and 4 part elevations at right angles to each other, and Fig. 5 a plan, of a
wooden casing enclosing parts thereof.
Fig. 6 is a similar view to Fig. 4 but drawn to a smaller scale.
Figs. 7 to 13 are detail views of parts of the apparatus.
Referring to Figs. 1 and 2:-
1 is a pump having its suction connected with the upper end of a vessel 2, and its
delivery connected by a pipe 3 with a tube or vessel 4 that is cooled by water and
is in communication with the bottom of the said vessel 2 by a pipe 5 provided with
a non-return valve 6. This valve is regulated by hand or like a reducing valve to
open sufficiently to permit only the passage of that portion of circulating fluid
that is reduced to the liquid or semi-liquid state. 7 is a second pump similarly
connected with a vessel 8, the cooling tube 9 by which its delivery is placed in
connection with the lower end of the said vessel 8 being arranged within the vessel 2.
10 is an air compressing pump (or there may advantageously be a combination of
three of such pumps) similarly connected with a third cooling vessel 11 through a
cooling tube 12 arranged within the vessel 8. 6 is a valve like 6, placed in the
tube 9 connecting the tube 9 with the vessel 8; and 6b is another similar valve in
the pipe 13 connecting the tube 12 with the vessel. 11. The suction pipe 13
connecting the pump 10 with the upper end of the vessel 11 is provided with a
reducing valve 14 and with an air inlet valve 15. 16 is a pipe extending through
the vessel 11 so as to be cooled by the liquid therein. This tube is connected at
one end by a pipe 16" and chamber 17 with a fan or blower 18, and at the other end
with a separator. In the example shown this separator comprises a rotary or
centrifugal vessel 19 provided with separate outlet pipes 20 and 21 for nitrogen and
oxygen respectively. 1* 1* are pressure gauges.
The operation of this apparatus is as follows:-
An easily liquefiable volatile liquid such as sulphuric ether, is placed within the
vessel 2 and another volatile liquid having a much lower boiling point as for
example nitrous oxide, or carbon dioxide, is placed in vessel 8, and the pumps 1
and 7 set in motion so as to cause the liquids in the said vessels to rapidly evaporate.
The temperature of the tube 12 will in this way be reduced so low that upon passing
atmospheric air through such tube, by the pump 10 (or pumps) at a pressure of
about 300 atmospheres, such air which is admitted through the air valve 15, will be
liquefied and caused to enter the vessel 11 through the pipe 13. When sufficient
air has thus been liquefied, the air valve 15 is closed, the reducing valve 14 opened,
and the pump 10 still kept in operation, so that the liquid air will be caused to.
evaporate like the liquids in vessels 2 and 8, the gaseous air thus drawn off being
recompressed and liquefied in the tube 12 whence it again returns to the vessel 11.
14 and 14 are reducing valves arranged between the pump 7 and the vessel 8, and
the pump 1 and the vessel 2 respectively. The vessel 11 instead of being charged
with liquid air may be charged with liquid oxygen nitrogen or hydrogen, or a
mixture of these.
By the evaporation of the liquid in the vessel 11 the temperature of the tube 16
within the said vessel 11 will be reduced to a point below the boiling or liquefying
point of atmospheric air, so that upon air being now passed through such tube
from the fan or blower, it will become liquefied with very little if any additional
pressure, that produced by the blower being sufficient.
The liquid oxygen and nitrogen thus obtained can then be separated from each

page_text: other in various ways. Thus they may be allowed to pass into the vessel 19
wherein they are separated by centrifugal force, the oxygen, being the heavier of
the two, escaping through the pipe 21 which terminates at or near the circumference
of the vessel, and the nitrogen escaping through the pipe 20 which terminates at
or near the centre of the vessel. Or the nitrogen may be separated from the
oxygen by slightly heating the vessel containing them, as for example by allowing
atmospheric air to flow around it, whereby the nitrogen which has a boiling point
lower than that of oxygen, evaporates from and leaves the oxygen behind. To
assist this action a partial vacuum may advantageously be set up in the said vessel
by means of a pump. This evaporation of the nitrogen will serve to further lower
the temperature of the said vessel and the oxygen therein, and also that of mixed
oxygen and nitrogen gases that may enter the vessel, whereby the oxygen in the
mixture will be liquefied. The separation of the liquid oxygen from the nitrogen
may also be effected or assisted by placing the poles of a magnet within or below
the vessel containing these substances, whereby the oxygen will be attracted
whilst the nitrogen will be enabled to escape.
Usually the oxygen and nitrogen will be obtained liquefied together, but by
carefully regulating the temperature of the tube or vessel 16, it may be found
possible to arrive at a temperature at which the oxygen alone will liquefy, in
which case the unliquefied nitrogen can be readily got rid of.
In order to render the process economical, the various parts of the apparatus
should be carefully protected by non-conductors of heat so that they will not be
seriously affected by the heat of the surrounding atmosphere, and the air to be
treated should be reduced to as low a temperature as possible before it passes into
the final cooling tube or vessel 16 so that it will heat the liquid air in the vessel 11
as little as possible. For this latter purpose the cold oxygen and nitrogen after
being separated from each other are caused to flow through pipes arranged within
the cooling chamber 17 so that air flowing through this chamber will circulate over
such tubes and be reduced to a temperature approaching that at which it will
become liquefied before entering the tube 16. By thus cooling the air at the
expense of the separated oxygen and nitrogen and keeping the pumps in action,
the separation of the oxygen and nitrogen of atmospheric air can be effected in a
continuous rapid and economical manner and on a large scale. Other more readily
liquefiable fluids such as water vapor; sulphur dioxide; carbon dioxide etc. that
may be present in the air will be liquefied and removed therefrom by contact with
the tubes (hereinafter called regenerating tubes) through which the separated and
cold oxygen and nitrogen pass. These Huids thus liquefied or solidified may be
re-converted into gas or liquid and disposed of by permitting the temperature of
the regenerating chamber to rise from time to time, when some of them will
escape in the liquid state and some in the gaseous state. The remaining gases,
oxygen and nitrogen, pass on to be further cooled and separated as hereinbefore
described.
In the arrangement of apparatus shown in Figs. 2 to 13 inclusive 1, 7 and 10 are
pumps; 2, 8 and 11 are vessels through which sulphuric ether, nitrous oxide and
liquefied air respectively circulate; and 4 is a water cooler, these parts being
connected, arranged and operating substantially in the manner hereinbefore described
with reference to the arrangement shown in Figs. 1 and 1ª. In Figs. 2 however
there are six final cooling or liquefying vessels 11 each of which is connected at
the lower end with the tube 12 by a main tube 13" and branch tubes 13, and at the
upper end are connected to the pump 10 by a main tube 13 and branch tubes 13,
each vessel 11 being traversed by a tube 16 within which the air to be treated is
liquefied. The vessels '8 and 11 and tubes 12 and 16 are arranged within the upper
part 22 of a wooden casing shown in Figs. 3 to 6 inclusive, and are connected
together by means of hydraulic piping such as is shown in Figs. 7, 8 and 9. This
piping is connected to the several tubes and vessels by metal to metal joints as
shown, escape of fluid between the parts being prevented by packing rings 23 of
material such as‘gutta percha that are compressed tightly in place by nuts 24 and

page_text: :
glands 25 (Fig. 7^) that are prevented from rotating by pius 25". The air wholly
or partly liquefied in the tubes 16 is led by separate pipes 26 to a closed evaporating
vessel 27 (Figs. 10, 11 and 12) of non-magnetic material such as brass that is fixed
within the intermediate part 28 of the wooden casing. In this vessel the nitrogen
is separated from the liquid oxygen, it may be by evaporating off the nitrogen in
the manner herein before explained; the separated oxygen and nitrogen pass off
by the outlet pipes 30 and 31 respectively each of which is connected with a
regenerating tube 34 (or tubes) arranged within the lower portion 32 (Figs. 3, 4
and 6) of the wooden casing through which the air to be treated flows on its way
to the upper ends of the tubes 16. To separate the oxygen and nitrogen by
magnetic means the following arrangement may be used. 29 is an electro-magnet
consisting of a tube bent to the form of a horse shoe it has a tubular extension 29°
that is in communication with the vessel 27, and a hollow armature or connecting
piece 29 of non-magnetic material that is in communication by an exit pipe 29°
with one of the regenerator tubes 34 (Fig. 10). By this arrangement when the
electro-magnet is excited, the liquid oxygen will be retained in the hollow magnet
and the lower part of the vessel 27 until a considerable head has accumulated in
the latter vessel whilst allowing the nitrogen to escape in a gaseous or liquid state
through the pipe 31. The pressure due to the head of liquid oxygen or nitrogen,
or both, is utilized, when it has attained a predetermined amount, by passing through
a pipe 27 or gauge-glass 29d to operate a flexible diaphragm 29 and move a
contact 29 from a contact 29, and thereby break the circuit of the magnet winding
and enable the then demagnetized oxygen to pass to a holder by way of the pipe 29°
and regenerator tube 34. When the head of liquid has passed away, the diaphragm
contracts and enables the electric circuit to be re-established and the magnetisation
and retainment of the oxygen to be repeated.
The lower part 32 of the casing is provided with a door 33 (Figs. 3 and 4) by
which fluid substances separated from the air by reason of the preliminary cooling
to which it is subjected by contact with the regenerator tubes, can be removed.
Each regenerator tube 34 may be formed with external ribs 35 as shown in Fig. 13,
in order to present a large cooling surface to the air flowing over it. The
evaporating vessel 27 may be provided with outlet pipes 27" to which a gauge glass
can be attached, and with a pipe 27° for the reception of any suitable form of
thermometer, as for example a hydrogen thermometer in which the expansion and
contraction of hydrogen due to changes of temperature in the evaporating vessel
can be caused to displace liquid in the connected legs of a tube, the arrangement
somewhat resembling a differential air thermometer.
If desired the sulphuric ether vessel 2 and pump 1 could be dispensed with, but
I prefer the arrangement described as the nitrous oxide will not then need to be
compressed to so great an extent and there will consequently be less liability of
leakage.
To separate carbon dioxide or nitrous oxide from those gases with which they
are usually mixed, it is only necessary to cool them in the manner hereinbefore
described to a sufficient extent to cause liquefaction of the carbon dioxide, or
nitrous oxide, as the case may be which can be easily accomplished inasmuch as the
gaseous impurities present with carbon dioxide, if it be obtained by the combustion
of coke or coal, or by burning limestone will be mainly water sulphur dioxide,
carbonic oxide, oxygen and nitrogen. The liquefying point of water is of course
above the temperature of the atmosphere, and that of the sulphur dioxide is near
that of the atmosphere, whilst the carbon dioxide does not liquefy until a tempera-
ture of about 780 is reached. There is therefore a wide margin of difference
between the liquefying points of the substances mentioned and also between that of
carbon dioxide and the carbonic oxide, oxygen and nitrogen present which latter
will consequently pass away in the gaseous state.
The gaseous impurities usually present when making nitrous oxide are nitrogen
and nitric oxide, but as nitrous oxide liquefies far before the liquefying point of
nitric oxide or nitrogen is reached, it is only necessary to allow the three to pass

page_text: together into a vessel such as herein described wherein they are cooled or compressed
sufficiently to liquefy the nitrous oxide which can then be drawn off from the lower
portion of the vessel whilst the still gaseous nitrogen and nitric oxide can, when the
separation is effected by pressure or cold and pressure be allowed to escape into the
atinosphere or other place by a suitable escape valve when the pressure exceeds
that necessary to keep the nitrous oxide liquid.
When thus separating carbon dioxide and nitrous oxide, the liquid air pump 10,
vessel 11 and tube or tubes 16 will not be necessary, liquefaction of such gases
being effected in the tube or vessel 12 through which they are then caused to pass,
the liquid and unliquefied products passing to an evaporating vessel such as 27
(Figs. 10 and 11) whence the liquefied and unliquefied products are drawn off
through separate outlets as before. If the nitrous oxide (NO) contains chlorine,
the regenerating chamber will be sufficiently cold to liquefy it therein, or any other
impurity that will liquefy below the liquefying point of nitrous oxide.
Gaseous compounds such as nitrous oxide or carbon dioxide that can be readily
liquefied by pressure alone may be separated from other gaseous substances by this
means without cooling, the liquefiable gases being allowed to collect, in the order
in which they liquefy, in separate vessels. One gas may thus be separated from
another and collected for use, or the liquefied and unliquefied fluids may be passed
into a vessel together so that if it be required to obtain only one particular
constituent of the mixture say for example carbon dioxide, then assuming that this
gas happens to have the lowest liquefying point, that is to say requires the least
pressure to liquefy it, (as would be the case if carbon dioxide, nitrogen and oxygen
were mixed) then the carbon dioxide would be in the liquid state whilst the
nitrogen and oxygen would still be in the gaseous state. By employing a release
valve arranged to blow off at a pressure greater than the pressure necessary to keep
the carbon dioxide liquid, the nitrogen and oxygen can be automatically separated
and allowed to escape from the liquid carbon dioxide which can be afterwards
drawn off when desired in an almost, if not perfectly, pure and of course liquid
state.
Nitrous oxide can be separated by pressure in a similar manner from chlorine,
nitric oxide, nitrogen and water vapour, the degree of pressure necessary to liquefy
the nitric oxide and nitrogen being far greater than that necessary for liquefying
the chlorine or nitrous oxide, whilst the water will separate out by condensation
in the usual way.
In like manner hydrogen may be separated from water gas, as the carbonic
oxide and hydrogen of which water gas consists have two different points of
liquefaction the hydrogen being the more difficult of the two to liquefy. Upon the
carbonic oxide being liquefied in the manner described, the hydrogen is allowed to
escape in a gaseous state to a suitable vessel or chamber, or where desired. As
carbonic oxide is liable to attack steel, iron and nickel, it is desirable when using
vessels of these metals to enamel or line them, or to use vessels made of such metal
as brass or copper. In other respects apparatus such as hereinbefore described for
the separation of the constituents of atmospheric air, would be suitable for the
separation of carbonic oxide from hydrogen. In the manufacture of coal gas, the
impurities associated therewith could be got rid of by liquefying them (either by
pressure or cold or both combined) in their relative order, and permitting the
gaseous mixtures to pass on to be further separated.
The impuritics usually present in coal gas are
Water (H2O), which liquefies at the normal temperature;
Sulphur dioxide (SO2), which liquefies at about
Ammonia (NH₁)
Sulphuretted hydrogen (SH)
Carbon dioxide (COS
"
33
"
10° C.;
38° C.;
63° C.; &
700 1

page_text: the gases thus separated could be stored if desired & utilized as commercial
commodities, and it may be found advantageous to return some of the separated
gases to the coal gas to increase its illuminating or heat-giving properties. By the
means described coal gas can thus be purified in an easy, convenient and economical
manner.
Gases such as oxygen, carbon dioxide and others obtained in the manner
described can be advantageously used in various industrial processes as well under-
stood. For instance oxygen can be used for effecting combustion in cases where
atmospheric air is at present used in which the oxygen is accompanied with over
four times its volume of inert nitrogen which must disadvantageously be raised in
temperature. The oxygen can also be used for smelting, brazing and welding
inctals, or other purposes where intense heat is required, or is required in an
exceedingly brief time. It can also be used for effecting the combustion of water
gus for heating purposes as for example the decomposition of limestone (CaCO₂)
from which comparatively pure CO₂ can then be obtained. This latter gas (CO₂)
can be used for motive power and other industrial purposes.
Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed I declare that what
I claim is :-
1. The herein described method of separating and obtaining the constituents of a
gaseous mixture by causing such mixture by reduction of temperature produced by
the volatilization of a volatile liquid, or by pressure, or by both of these means
combined, to assume a condition in which the desired constituent or constituents
will become liquefied and thus separated from the remaining gas or gases, the
liquefaction in the case of its being desired to obtain two or more of the constituents
separately, being effected in successive stages corresponding to the liquefying
points of the gases to be obtained.
2. The herein described method of separating oxygen from nitrogen by subjecting
the mixture of such gases to great reduction in temperature by the rapid volatiliza-
tion of a fluid having a low boiling point, such for example as liquid air (produced
by the joint agency of pressure and cold), whereby the said oxygen and nitrogen
are liquefied, and then separating the mixed liquid oxygen and nitrogen from ench
other as set forth.
3. In the method of separating the constituents of a gaseous mixture by
reduction of temperature as referred to in the preceding claims, utilizing one or
more of the separated and cold constituents to reduce the temperature of further
quantities of gaseous mixture by causing it or them to flow through pipes or
Conduits with which the gaseous mixture is caused to come into contact on its way
to the liquefying chamber, and whereby other liquefiable gas or gases that may be
resent in the inflowing gaseous mixture may be liquefied and removed as set forth.
4. For carrying out the methods referred to in the preceding claim apparatus
constructed, arranged and operating substantially as hereinbefore described with
eference respectively to and shown in Figs. 1 and 14 and in Figs. 2 to 13 inclusive
of the drawings annexed, or modified as set forth.
Dated this 5th day of December 1892.
W. LLOYD WISE,
Per F. J. Brougham,
46, Lincoln's Inn Fields, London, W.C., Agent for the Applicant.