Method of and Apparatus for Treating Atmospheric Air to Obtain Oxygen therefrom.
Year: 1890

page_text: Date of Application, 28th Apr., 1890-Accepted, 10th Jan., 1891
COMPLETE SPECIFICATION.
Method of and Apparatus for Treating Atmospheric Air to Obtain
Oxygen therefrom.
I, EDWARD NEAVE, of the firm of Neave & Co., Gas and Sanitary Engineers,
of 335 Pitt Street, Sydney, in the Colony of New South Wales, do hereby declare
the nature of this invention and in what manner the same is to be per-
formed to be particularly described and ascertained in and by the following
statement:
This invention consists of a method of and an apparatus for treating atmospheric
air to extract the oxygen or part of the oxygen therein contained.
In carrying out the present invention heat is not employed; but the property which
is possessed by membranes of permitting the passage through them of denser gases more
rapidly than comparatively rare gases is availed of to separate such gases when
mechanically mixed together, as in the air of the atmosphere.
To make the principle of the invention and the method of performing the same
fully understood I have annexed hereto a sheet of explanatory drawings, in which
1 represents the nitrogen eduction tube; 2 and 3 air pumps, the supply to which
respectively is through the tubes 4 and 5; 6 oxygen eduction tube; 7 air vessel;
8 valve; 9 uptake tube leading to first purifying vessel; 10 purifying vessel con-
taining a solution of calcium hydrate in water; 11 air vessel; 12 tube leading from
air vessel 11 into purifying chamber 13 which is like the vessel 10; 14 air vessel;
15 tube from air vessel 14 leading into supply to air pump 16; 17 oxygen delivery
tube leading from pump 16 to container; 18 separator, in which A is a cylinder of
porous clay B carbon diaphragms in same; C thin india-rubber jacket enclosing
porous cylinder A closely, and cemented to the same at the ends; D india-rubber
heads; packing; F chambers containing masses of porous caoutchouc, prepared as
hereinafter described.
The caoutchouc contained in the chambers of the separator is prepared by being
first dissolved in naphtha and the naphtha then evaporated off the residue then again
dissolved in naphtha mixed with a quantity of oil of turpentine or oil of lavender and
these solvents again evaporated; the caoutchouc which remains will then be found to
be in a porous or spongy state.
The action is as follows:-
The air pumps 2 and 3 are single acting; whilst one is feeding the other is
exhausting. The pump 3 being given the first effective stroke partly exhausts the
contents of the chambers F consisting chiefly of oxygen, which is found to pass
through the rubber jacket much faster than nitrogen will. The second effective
stroke is given by the pump 2, the residual gas in the chambers F consisting
chiefly of nitrogen being thus withdrawn and sent to waste through the tube I..
The pump 3 being now brought into action, a further supply of air rich in oxygen
is drawn into the separator and thence is drawn through the spongy caoutchouc
into the barrel 3, and, as before, ejected through the tubes 6 and 12 into the
solution of calcium hydrate in the vessels 10 and 13, through which it is drawn,
and from the latter of which it passes by the tube 15 into the pump 16, which in
turn delivers it through the tube 17 into a suitable container. In passing through
the vessels 10 and 13 the gas comes into contact with the solution of calicum
hydrate therein, and nitrogen being absorbed by the water in greater proportion
than oxygen, the residual volume of the latter becomes purer as the process con-
tinues. Thus, the larger number of wash vessels employed, the purer will be the
product of oxygen. I prefer to force the product of oxygen through the vessels 10
and 13 rather than draw it through the same, and further to heat the calcium
hydrate solution so as to increase its capacity for absorbing nitrogen.

page_text: I do not limit myself specifically to the details of apparatus herein described as the
same might be modified and varied in various ways without departing from the
principle of the invention. I wish it to be understood also that I do not claim dis-
covery of the principle enunciated herein that denser gases will pass through
membranes more expeditiously than will comparatively rarer gases; nor do 1 claim
discovery of tlie applicability of such principle to the disintegration of atmo-
spheric air.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, I declare that what I
claim is:
1. A method of treating atmospheric air to obtain oxygen therefrom, consisting
essentially in causing the passage thereof through one or more membranes, pre-
ferably by the action of a vacuum at one side of the same, said membrane or
membranes being stretched over unglazed earthenware or other such porous
substance, preferably in the form of a cylinder, in operation vacuum being alternately
formed by a pair of pumps or their equivalents, the one of which giving first
stroke in each cycle will draw off a gas richer in oxygen than will that giving
second stroke therein; substantially as described.
2. In the treatment of atmospheric air to obtain oxygen therefrom by the applica-
tion of the principle of the unequal diffusion of gases through diaphragms and porous
walls, the use of caoutchouc or its, equivalent made spongy and porous by being
dissolved in a vaporizable substance such as naphtha, to which preferably spirit is
added; as and for the purposes set forth.
3.-The combination and general arrangement in the extractor 18, of porous case A,
carbon partitions B therein, membrane C, heads or covers D; and eduction tubes 4
and 5.
4. In a process wherein the proportion of nitrogen in atmospheric air is materially
reduced and the relative proportion of oxygen thereby increased, passing the product
through water containing calcium hydrate in solution to further reduce the proportion
of nitrogen.
Dated this 28th day of Annil 1900
ALLISON BROS.,
Agents for the Applicant.