Improvements relating to the Production of Oxygen Gas, and Apparatus therefor.
Year: 1895

page_text: Date of Application, 24th June, 1895
Complete Specification Left, 11th Nov., 1895-Accepted, 11th Jan., 1896
PROVISIONAL SPECIFICATION.
Improvements relating to the Production of Oxygen Gas, and
Apparatus therefor.
ALFRED SWEETSER 67 Croxted Road West Dulwich in the County of Sarrey
Consulting Engineer do hereby declare the nature of this invention to be as
follows:-
1
The object of this invention is to produce oxygen gas, but more especially to
produce it, as it is required to be used, for the limelight for optical lantern
purposes.
In carrying out my invention, I employ two gastight vessels, connected together
by a tube; the first vessel is fitted with a reel, on which is wound one end of a
suitable chain, or band of metal, asbestos, or other inorganic material, capable of
holding or containing chlorate of potash, or other such like material, which gives
off oxygen gas by the application of heat; the other end of this chain, or band, is
led under a suitable feed roller, and through the aforesaid tube connecting the
two vessels, such tube being kept hot by a suitable lamp, or other source of
heat.
The action is as follows:-Upon revolving the outside crank handle, with which
the aforesaid feed roller is fitted, the chain, or band, is pushed, or drawn through
the aforesaid heated tube, when the chlorate of potash gives off its oxygen, and the
residuum being driven on, enters the second vessel, and is dissolved in the water
with which it is charged. The residuum does not come in actual contact with the
heated metal tube, owing to the intermission of a part of the aforesaid chain, or
band, but simply slides over it, so it is always clean, and free to give off its heat to
the portion of the chlorate of potash chain, or band, lying upon its surface. By
these means the production of the gas is under perfect control, as only a small
portion of the aforesaid chain, or band, is exposed to the heat at any one time, so
that the supply of gas can be increased, or diminished, or stopped altogether, by
simply increasing, or diminishing, or stopping the feed of the chain, or hand. The
aforesaid chain, or band, can be worked either by hand, or by a suitable clockwork,
or other motor, so as to render the production of gas automatic.
It will be obvious that instead of the chlorate of potash forming part, and parcel
of the aforesaid chain, or band, it could be fed on to it as it travels through the
heated tube, and the chain, or band, could be endless, travelling over suitable
pulleys. Or in place of the chain, or band, suitable cakes of chlorate of potash-
protected from coming in contact with the heated surface of the tube as aforesaid-
could be fed over the heated surface. Or one or both vessels might be dispensed
with, the chlorate of potash could be passed in from the outside through suitable
elastic openings, or air locks.
If it is necessary to have the oxygen free from chlorine, I pass the gas as it is
liberated from the chlorate of potash, over thin sheet metal, or metal in a fine state
of subdivision.
The receiver for the gas I construct of sheets, or discs of material, which I join
together alternately, in the centre, & at the edges, so forming cells, the dividing
portion of the aforesaid sheets or discs being pierced to allow the gas to circulate.
Dated this 24th day of June 1895.

page_text: Improvements relating to the Production of Oxygen Gas, and
Apparatus therefor.
I, ALFRED SWEETSER of 67 Croxted Road, West Dulwich, in the County of
Surrey, Consulting 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 has for its object an improved method of and means for producing
oxygen gas in readily regulated quantities for use with the oxy-hydrogen lime
light or for use in hospitals or for other purposes.
According to my invention I produce the oxygen gas from chlorate of potash or
other suitable substance that when heated gives off oxygen, the said substance
being made up into cakes, rods or slabs of conveniently small dimensions, each cake,
rod or slab being wholly or partially enclosed in a casing formed of asbestos cloth
or other suitable fabric to prevent contact between the oxygen yielding substance
and the hot metal tube in which the gas is generated as hereinafter explained. I
.generate the gas by passing the aforesaid cakes, rods or slabs of oxygen-yielding
substance successively through a heated tube which communicates with a receiver
for holding the gas. The chief feature of my invention is the continuity of the
process, the cakes being fed into and through the generating tube in succession,
and the spent cakes being at the same time delivered into a receptacle adapted to
receive them or passed out of the tube without necessitating any stoppage of the
.generation of gas. The cakes may be independent of each other or they may be
connected together by flexible connections to form a chain of cakes, or they may
be mounted on a flexible belt or band for convenience in passing them into and
through the tube. The generating tube may be provided with an elastic washer or
with two or more such washers through which the cakes cau be successively passed,
or in lieu of washers an "air-lock "or similar device may be used to allow of the
introduction of the cakes while preventing the escape of gas. In order to confine
the generation of the gas to the cake or cakes which is or are located in the hottest
part of the tube, I sometimes shield the succeeding cakes by an asbestos or like
sleeve that protects them from the heat and prevents the generation of gas
therefrom while they remain in the sleeve; at other times for the same purpose
.I separate the adjoining cakes by a block of asbestos or other non-conductor of
heat.
In the accompanying drawings I have shown a convenient form of apparatus for
carrying my invention into practice the said apparatus being constructed for
the use of separate pieces of oxygen-yielding substance made up into the form of
-rods.
Figure 1 is a side elevation partly in section of the apparatus.
Figure 2 is a front elevation of the same.
Figure 3 is a perspective view of one of the rods of oxygen yielding substance
enclosed in asbestos cloth as hereinafter described.
Figure 4 is a perspective view of a number of flat cakes mounted on a flexible
.belt.
Figure 5 is a longitudinal section of a special form of apparatus constituting an
"air-lock" for introducing the rods into the generating tube.
Figure 6 is a transverse section on the line x, x, Figure 5.
In
Figures 7 and 8 are views of two rods of oxygen yielding substance furnished
with end pieces to prevent the conduction of heat from one rod to the next.
Figure 8 the end-pieces are shown in section.
Like letters of reference denote similar parts throughout the figures.

page_text: A is a box for enclosing the apparatus and serving as a packing box therefor;
the front of the box is removed to show the expansible gas holder B for storing the
generated gas. C is the generating or heating tube connected to the side wall of
and communicating with a chamber D that forms a receptacle for the spent cakes.
The said chamber is supported on the movable rigid top or cover B' of the
holder B. E is a lamp also resting on the top or cover B1 and situated immediately
under the tube C. By supporting the apparatus on the top of the expansible
holder as above described the necessary pressure is obtained in the holder without
the employment of separate weights for compressing the holder. In some instances
however it will be necessary to add separate weights where more pressure is
required than would be produced by the weight of the apparatus alone. F is a
removable bent sheet metal cover placed over the tube C and furnished with short
inwardly projecting supporting pins F¹ that rest on the said tube. The cover F
serves to concentrate upon the tube the heat given off by the lamp and to shield the
operator. G is a cake of chlorate of potash or other oxygen yielding substance
within the tube C at a point immediately above the lamp E and therefore in the
hottest part of the tube. It is this cake that parts with its oxygen when the tube
is heated. G¹ G¹ G¹ are three other cakes ready to take successively the place of
the cake G when the latter is spent. G2 is a spent cake which, on the introduction
of another cake into the tube, will be pushed forward into the chamber D. The
said chamber is made large enough to hold a number of such cakes. At the top of
the chamber D is an opening closed by a screw cap D'. On removing this cap the
spent cakes may be taken out of the chamber when required. H is a pipe for
conducting the generated oxygen gas to the holder B. J is a pipe for leading the
gas to the burner.
K is a sleeve made of asbestos or other suitable material lined with a metal tube
to afford support therefor and fitting tightly in the tube C or removably secured
thereto in any suitable manner. The said sleeve K protects the cakes G', G', G'
from the great heat of the tube C and so confines the generation of the gas to the
cake G immediately above the lamp. To prevent the escape of gas at the outer
end of the tube C, 1 provide one, two or more india rubber washers L placed in the
sleeve K and separated from each other by metal rings M which are held in place.
by the screw cap N. The washers tightly embrace the cake G¹ last introduced
into the tube and produce a gastight joint therewith.
The cakes of oxygen yielding substance are encased in asbestos which prevents
actual contact between the said substance and the hot tube and hence the latter
does not become fouled and is always in a condition for giving up its heat
efficiently to the said substance. The asbestos covering or casing preferably does
not completely surround the oxygen yielding substance but a strip of the said
substance is left uncovered as indicated in Figure 3.
P is a guide rod secured to the box A and passing through an eye in an arm P¹
of a block P2 secured to the chamber D. The said rod serves to guide the
chamber D as it rises and falls in accordance with the supply and removal of gas to
and from the holder B. Q is a spring-controlled relief valve placed in an opening
in the block P2 which opening communicates with the interior of the chamber D by
a passage Q'. The stem Q2 of the valve projects above the top of the block P² in
position to strike a plate T fixed on the top of the guide rod P when the gas
holder B is full, so that if more gas is generated than the holder is capable of
holding the holder will expand until the stem Q2 strikes the plate T whereupon the
valve will be opened and the surplus gas allowed to escape into the atmosphere.
The stem of the valve is made of triangular section and the hole in which it
works is circular so that the gas can escape past the stem when the valve is
open.
The use of small cakes as above described is very advantageous for optical lautern
purposes and for many other purposes, as the generation of the gas can thereby be.
effectively controlled, and their use is very simple and does not demand any
particular skill on the part of the operator. The cakes are pushed into the tube

page_text: one after the other and after each cake is spent it is pushed into the chamber D its
place being taken by another cake. The rate at which the cakes are fed forward
will within limits determine the speed of generation of the gas. As before stated
the generation of the gas can always be relied upon, and the tube C does not
become fouled but is always preserved quite clean. The cakes can be conveniently
and cheaply transmitted through the post without risk of accident and they together
with the simple apparatus above described are a most effective substitute for the
clumsy and dangerous gas bags and gas bottles that have been hitherto so commonly
used.
I sometimes connect the cakes together by flexible strips of fabric to form a
continuous chain of cakes or I mount the cakes on a flexible band R (see Figure 4)
made of asbestos or other suitable material. In addition to being mounted on the
band R the cakes may be further separately covered with asbestos to prevent
contact of the same with the sides of the hot tube. The said tube need not
necessarily be round but may have any suitable cross section adapted to the shape
of the cakes.
The chain of cakes may be pushed into the tube as required by hand, or by
means of a train of clockwork one wheel of which is adapted to engage with the
cakes and to feed them regularly into the tube.
I sometimes attach to the end of the cakes a piece U (see Figure 7) of asbestos,
porcelain or other bad conductor of heat to separate the cakes and prevent the too
ready conduction of heat from one to the other whereby I avoid the generation
of oxygen from those cakes which are not advanced to the hottest part of the
tube.
For the same purpose I sometimes apply caps V Figure 8 to the ends of the
cakes, the said caps being made of non-conducting material and so arranged that
there is an air space between the caps and the ends of the cakes.
In some instances the receptacle D is dispensed with and the cakes are passed
out of the end of the tube through washers similar to the washers L. In other
instances a closed chamber similar to the chamber D is provided at each end of the
tube, and in that case the cakes are fed forward as required by means of a wheel or
similar device rotated by hand or by clockwork. The said chambers are furnished
with doors or covers to admit of charging the apparatus with a fresh chain of cakes
and of removing the spent cakes when the same are exhausted. In some instances
the cakes would be mounted on an endless band.
In Figures 5 and 6 1 have shown an alternative mode of introducing the cakes
into the generating tube while preventing the escape of gas therefrom.
In these figures W is a tube closed at both ends and arranged to slide through a
long stuffing-box or chamber W₁ applied to the end of the generating tube C.
W is a slot or opening in the side of the tube W large enough to admit a cake G.
W is a push plate on the inner end of the tube W. To pass a cake G of oxygen
yielding substance into the generating tube, the said cake is first passed through
the slot W into the tube W and then the latter is pushed forward into the
generating tube and turned round until the slot W' is at the bottom whereupon the
cake G drops out of the tube W into the generating tube. The tube W can then
be drawn back and turned to receive another cake G. When the tube W after
being drawn out is turned to bring the slot to the top, the push plate W³ passes
behind the end of the cake G last introduced into the tube so that when next the
tube W is advanced it pushes forward the said cake and makes room for the next
cake. The stuffing-box or chamber W₁ must be longer than the slot W³ to prevent
the escape of gas when the tube W is being moved in and out.
In lieu of dropping the cake out of the tube W in the manner described as soon
as it is introduced I may retain it in the tube W until it is exhausted and then
either withdraw the tube W remove the spent cake and substitute a fresh cake, or
discharge the spent cake into the tube Ċ then withdraw the tube W re-charge it
with another cake and push the tube W in again.
In some instances in lieu of making up the oxygen yielding substance into cakes

page_text: as above described I use it in the form of powder or crystals, and I provide a
travelling band furnished with cups or receptacles which can be caused to pass
through the heating tube C. The powder or crystals is or are fed into the
said cups or receptacles from a hopper or otherwise in accordance with the
requirements.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
1. A continuous process of generating oxygen gas from cakes of oxygen-yielding
substance by introducing such cakes successively into a heated tube, and
simultaneously ejecting the spent cakes, into a receptacle or chamber such as D,
substantially as described.
2. A continuous process of generating oxygen gas from cakes of oxygen yielding
substance connected together by flexible connections to form a chain of cakes, or
mounted on a flexible band, by passing such chain or band through a heated tube
by hand or by means of clockwork, substantially as described.
3. The modification of the said process wherein I use oxygen yielding substance
in the form of powder or crystals fed into cups or receptacles fixed on a band that
is passed through the heated tube, substantially as described.
4. In the manufacture of oxygen gas the employment of cakes of oxygen yielding
substance encased in asbestos cloth, with or without the end pieces or caps of non-
conducting substance, substantially as, and for the purpose, specified.
5. A flexible band on which are mounted a number of cakes of oxygen yielding
substance wholly or partially covered with asbestos and separated or not by strips
of asbestos or other non-conductor of heat, substantially as described, and for the
purpose specified.
6. The sleeve K for protecting the cakes that have not been advanced to the
hottest part of the tube, substantially as described.
7. The means for preventing the leakage of gas from the outer end of the
generating tube, substantially as described.
8. The combination, with the generating tube, of a box or chamber for receiving
the spent cakes, and in some instances another box for receiving the chain of cakes
before they are delivered to the generating tube, substantially as described.
9. An apparatus for generating oxygen gas comprising a generating tube C,
a receptacle such as D for the spent cakes, a gas holder B, and a lamp E,
substantially as described.
10. The means for introducing the cakes of oxygen-yielding substance into the
generating tube substantially as described with reference to Figures 5 and 6.
11. The apparatus constructed substantially as described with reference to
Figures 1 and 2 of the accompanying drawings, and operating as specified.
Dated this 11th day of November 1895.
ALFRED SWEEIDER,
Haseltine, Lake & Co.,
45, Southampton Buildings, London, Agents for the Applicant.