An Improved Method of Charging Liquids with Gas.
Year: 1889

page_text: Date of Application, 11th Oct., 1889-Accepted, 16th Nov., 1889
COMPLETE SPECIFICATION.
[Communicated from abroad by CHARLES ALBERT CATLIN, Chemist, CORNELIUS
LOWLE SWEETLAND, Bank President, both of Providence, Rhode Island, United
States of America, and ROWLAND Cox, Lawyer, of Plainfield, New Jersey,
United States of America.]
An Improved Method of Charging Liquids with Gas.
1, HENRY HARRIS LAKE of the firm of Haseltine, Lake & Co., Patent Agents,
Southampton Buildings in the County of Middlesex 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 :-
The invention is applicable to mixed gases alone and its object is to effect the
separation of a pure gas from the mixed gas and the combination of such pure gas
with the liquid in a more simple and expeditious manner than any hitherto known.
Broadly speaking the methods of separating a pure gas from a mixed gas and
combining the pure gas with a liquid heretofore used are two in number, of which
one may be recognized by the use in one form or another of apparatus constructed,
upon the principle of the Woulf bottle while the other is practised by passing a
current of mixed gas through a closed vessel or a series of closed vessels in one
direction over the surface of a liquid continuously flowing through such vessel or
vessels in the opposite direction and at the same time agitating such flowing liquid,
so that it is thrown up into the mixed gas. The well known tower system or
method may be considered as a combination of the two methods just mentioned.
The tower method retains, while my method overcomes the disadvantages of both.
The disadvantage of the Woulf bottle method is that either the mixed gas must be
purified and the pure gas separated therefrom before it is passed through the liquid
in the bottles (or the tanks taking the place of the bottles) or an unnecessary
expenditure of force is required to drive the inert gases of the mixed gas through
the liquid and entire apparatus.
The disadvantage of the other old method is the difficulty in regulating the
continuous flow of the liquid through the apparatus so that the product as it flows
from the apparatus in a continuous stream, shall be neither too little nor too much
charged with the gas.
By my method the mixed gas passes over the surface of the main body of the
liquid instead of through it, and the union between the liquid and the pure gas is
assisted by agitators which throw up spray from the liquid into the mixed gas, but
the liquid instead of flowing through the apparatus continuously is drawn inter-
mittingly from tank to tank. As in apparatus already in use after the operation has
once begun the mixed gas, when strongest in the gas to be combined is brought into
contact with liquid already charged therewith to some extent and thereafter as it loses
its strength in the gas to be combined, is brought necessarily into contact with liquid
less and less charged therewith, but so far as the liquid is concerned the operation
going on in each tank is distinct from that in any other. A charge of liquid does
not lose its identity but is progressively brought into contact with the mixed gas that
is stronger and stronger in the gas to be combined. The strength of each charge is
consequently known at all times by the workman.
My invention has been made with especial reference to the production of an acid
sulphite solution of magnesia by exposing water holding powdered oxide of
magnesium in suspension to the fumes of burning sulphur, which consist mainly of
sulphurous acid and nitrogen. The process, however, is applicable to the combination
of other solutions and gases. I have also devised apparatus for carrying out the
process or method herein described.

page_text: The apparatus which I employ and the mode of operation may be briefly described
as follows; Several cylindrical tanks each provided with an agitator are connected
in series from top to top so that a gas entering one may flow freely through them all,
passing along the upper portion of each tank in succession. The lower part of each
tank is filled with the liquid to be charged or combined.
The agitators consist essentially, of arms adapted to revolve in vertical planes at
right angles to the flow of the gas, and thus to pass repeatedly through the liquid
below and the flowing gas above. The tanks are placed at different levels, and
besides their connection from top to top by pipes for the passage of gas as stated
above, they are so connected by other pipes provided with stop-cocks that the liquid
contents of the last tank to receive the gas may be drained at will into the next
preceding tank in series, and so on. The mixed gas is passed through this apparatus
until the liquid in the tank that is nearest the reservoir or generator is charged with
the required gas to the proper extent. The liquid so charged is now drawn off from
this first tank, but instead of supplying that tank with fresh liquid I draw into it the
partially charged liquid of the next tank and into that next tank I draw the liquid
of the tank beyond with such gas as it has taken up, and so on until the liquid,
whatever may be its condition is drawn from the last tank into the tank preceding
the last tank and this last tank I supply with fresh liquid.
The accompanying drawing shows partly in elevation and partly in section an
apparatus, such as I have used in manufacturing the acid sulphite of magnesia
solution so largely employed in the production of wood pulp.
A B and C are three cylindrical tanks lying horizontally one above another.
Each is provided with a horizontal shaft D passing centrally through its heads or
ends and having bearings outside thereof. Each shaft is provided with arms or
paddles a a reaching from the shaft to near the wall or shell of the cylindrical tank:
These arms or paddles are feathered in different directions. Suitable mechanism is
provided for revolving these several shafts. The tanks A and B are connected at one
side of the apparatus by a bent pipe E, entering the ends or heads of the said tanks
at that side of the apparatus near the top and in like manner on the other side of the
apparatus the tanks B and C are connected by the pipe F.
G is the reservoir containing the mixed gas, of which sulphurous acid is one of the
components and H is a pipe leading from said reservoir to the first absorbing tank A.
A pipe K provided with a stop cock as shown connects tank C with tank B so that
the contents of the former may be drawn into the latter at will and in like manner
and for like purpose a pipe L provided with a stop-cock connects tank B with
tank A.
M is a supply funnel in the top of the upper tank C, and N is a discharge-pipe at
the botton of the lower tank A.
P is an escape flue in the top of the last tank of the series at its rear end by which
the inert gases of the mixed gas finally escape.
Each tank is provided with several diaphragms or partitions b extending down from
the top between paddles on either side as shown to interrupt the direct current of
the gas through the tank. They must not, however be placed so low as to impede the
passage of the inert gases which form so large a proportion of the gas obtained
by burning sulphur in air.
In operating the apparatus I first fill each tank A B C with water to within a
short distance of the shaft adding thereto the required quantity of finely powdered
calcined magnesite, to give a liquor of the magnesia strength required and then
setting the agitators in motion admit into the tank A from the reservoir G through
the pipe H the mixed gas obtained by burning sulphur or pyrites or any mixed gas
containing sulphurous-acid gas or one of its components however obtained. The
draft in the escape flue P must be strong enough to draw the gas through the whole
apparatus and in some instances it may be necessary to use a fan or blower in aid of
the natural draft. The revolution of the agitators in the several tanks now throws
up the water and the particles of magnesia held in suspension, bringing the magnesia

page_text: "
in contact with the sulphurous acid. Little or no sulphurous acid escapes absorption
in the lower tank until all or the greater part of the magnesia in that tank has been
converted into the monosulphite, which being but slightly soluble in water, still
remains in the condition of fine solid particles suspended in the water. Gradually as
more gas is absorbed these particles dissolve and there is present in the tank a
solution of the so-called "bisulphite" which chemical combination, if combination
there be, is very slow and hence quite a large proportion of the sulphurous acid
escapes into the second tank, where, meeting with fresh magnesia, it is absorbed
with avidity and thus the formation of the monosulphite takes place while the so called
bisulphite" is forming in the first tank. The process goes on in the first tank A
even after the said bisulphite stage is reached. Since for the purpose required the
liquid should be further impregnated with sulphurous acid, and this being only in
mechanical acquisition a still larger proportion of the sulphurous acid now escapes
from the first tank A into the second tank B and thus the liquid in the second tank
becomes well advanced in the so-called "bisulphite" stage. Sulphurous acid now
begins to pass into the third tank C and the formation of the monosulphite begins in
that tank and this stage in the process is well advanced in the third tank when the
water and magnesia of the lower tank have acquired the requisite sulphurous acid to
be drawn off into the storage tank through the pipe. The liquid contents of the
first tank having been withdrawn and the valve in the discharge-pipe having been
closed the liquid contents of the second tank B which is now well advanced in the
so-called "bisulphite" stage are drawn into the first tank A and the contents of the
third tank (progressing in the monosulphite stage are drawn into the second tank
and a new charge of water and calcined magnesite is introduced into the third
tank and so the process is continued and we have regulating the quantity of the gas
supply by the capacity of the tanks three different stages of chemical combination
proceeding within the different tanks; first, the mechanical impregnation; second,
the weaker chemical combination, and, third the active chemical affinity which
catches and retains the excessive wastes of the sulphurous acid from the others.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed as communicated to me
by my foreign correspondents I declare that what I claim is :-
The herein described method of charging or combining liquid with gas consisting
in passing a current of mixed gas continuously through a series of tanks in one
direction passing the liquid intermittingly through the same tanks in the opposite
direction and agitating the liquid and gas all substantially as described.
Dated this 11th day of October 1889
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, Agents for the Applicant.