Improvements in or connected with the Treatment of Liquids by Gases.
Year: 1894

page_text: Date of Application, 26th Oct., 1894
Complete Specification Left, 23rd Aug., 1895-Accepted. 28th Sept., 1895
PROVISIONAL SPECIFICATION.
Improvements in or connected with the Treatment of Liquids
by Gases.
We, JAMES JONES MELDRUM, THOMAS FREDERICK MELDRUM, and JOHN
WESLEY MELDRUM, all of Atlantic Works, City Road, Manchester, Engineers,
do hereby declare the nature of this invention to be as follows :-
This invention has reference to the treating or operating upon liquids by gases,
and relates to the method of so operating upon liquids wherein the gas is distributed
by a perforated pipe, bottom, or the like, at or near the bottom of the liquid, and
is caused to pass through it. The kinds of liquids that may be so treated, and the
kind of gases used, are various; as for instance, foul, or impure, liquids may be so
treated by gases, as carbonic acid, air, or other gaseous agent, for their purification;
or, for the alteration of form or nature of a constituent or constituents thereof; or
for the removal of same, or both.
In the carrying out of the method above referred to, of treating liquids by gases
as usually practised, the streams of gas issuing from the holes in the distribution
pipe, plate, or the like, do not retain, in passing through the liquid, this form, viz.,
that of streams, nor of small bubbles, but soon coalesce, forming large globules
or bubbles of gas, thereby very materially reducing the area of aggregate surface
contact between the liquid and the jets diminishing the effect of the process. Now
the object of the present invention is the obviation of this deficiency due to the
above cause; to provide a relatively large time contact of gas with liquid; and
generally to provide improvements in connection with such treatments of liquids:
and by this invention these are attained :-Namely, by this invention, the full or
nearly the full surface area of the gas as it issues from the distributing means
referred to is maintained throughout the passage of the gas through the liquid, and
the increased time contact is attained; these being attained by the employment of
a series of perforated diaphragms, plates, or the like, placed one above the other in
the vessel in which the liquid is treated, by each of which the streams of gas
passing upwards are redistributed in the like manner as by the lowermost or initial
one or ones, breaking up the gas into streams and forming by cach diaphragm a
new series of fine jets, so giving the maximum surface contact and efficiency, and
obviating the formation of the relatively large bodies or bubbles of gas above referred
to, and the consequent defects; and further, as regards time contact, the rate of speed
of passage of the gases through the liquid is retarded by the diaphragms or the
like, and thus the time which the gas is in contact with the liquid is rendered
greater. Also, the perforated diaphragmns are caused to retain beneath each of
them an agitated film of gas, deeper or shallower according to the circumstances;
and the surface being continuously wetted, the gases will act upon the liquid on
this side of the plate as well as on the surface of the liquid below the film
whereby additional surface for contact between the gas and the liquid is made.
Another effect of the diaphragms or the like will be that in breaking up the
bubbles of gas, new surface will be exposed to the action of the liquid, whereas
when a bubble rises undisturbed from the bottom to the top of the liquid, the same,
or approximately the same particles of gas are continuously exposed to the liquid,
the central core being unacted upon.

page_text: The diaphragms are made, preferably, of perforated plates, whilst in some cases
they are made of woven tape or wire gauze. In some cases, however, tapered
bars, as grate bars, may be employed, the different layers of bars above one another
being placed at right angles to the adjacent layers.
In treating liquids with gases, as when treating sewage, or other foul, or impure
liquids with carbonic acid, i.e. carbonating it (or when oxydizing it by air), a
portion, say at one end or part of the, tank or vessel in which the, treatment is
being carried on, may be partitioned off, and so arranged that the liquid treated
may flow over the partition downwards, and then under, the lower edge of same
into the body of the liquid, so effecting a circulation thereof. Or, in lieu of such
construction, a. separate conduit or conduits may be employed outside the tank or
vessel to provide for the circulating or return flow.
In some applications of this invention, where a current of liquor is treated in
passing through a tank or vessel, the liquid is best run in over the uppermost
diaphragm, and passes downwards through the diaphragms or trays below, while
the gas passes upwards in the opposite direction; thus, the descending body of
liquid is acted upon by the rising streams of gas or air. Where, however, there
is not sufficient head of liquid, or where it may be deemed preferable, the liquid
may be run in at or near to the bottom of the tank or vessel instead of above, in
which case it will pass upwards with the gas through the diaphragms or trays,
being discharged from the top.
Dated this 95th day of October 1801
Improvements in or connected with the Treatment of Liquids
by Gases.
We, JAMES JONES MELDRUM, THOMAS FREDERICK MELDRUM, and JOHN
WESLEY MELDRUM, all of Atlantic Works, City Road, Manchester, in the
County of Lancaster, Engineers 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 reference to the treating or operating upon liquids by gases,
and relates to the method of so operating upon liquids, wherein the gas is distributed
by a perforated pipe, bottom, or the like, at or near the bottom of the liquid, and
is caused to pass through it. The kinds of liquids that may be so treated, and the
kind of gases used, are various; as for instance, foul, or impure, liquids may be so
treated by gases, as carbonic acid, air, or other gaseous agent, for their purification ;
or, for the alteration of form or nature of a constituent or constituents thereof;
or for the removal of same, or both. Conversely with the above, gases may be
treated or operated upon by liquids under this invention.
In the carrying out of the method above referred to, of treating liquids by
gases as usually practised, the streams of gas issuing from the holes in the
distribution pipe, plate, or the like, do not retain, in passing through the liquid,
this form, viz., that of streams nor of small bubbles, but soon coalesce, forming
large globules, or bubbles of gas, thereby very materially reducing the area of
aggregate surface contact between the liquid and the jets diminishing the effect of
the process.
Now the object of the present invention is the obviation of this
deficiency due to the above cause; to provide a relatively large time contact of gas
with liquid and generally to provide improvements in connection with such
treatment of fluids; and by this invention these are attained Namely, by this

page_text: invention, the full or nearly the full surface area of the gas as it issues from the
distributing means referred to is maintained throughout the passage of the gas
through the liquid, and an increased time contact is attained; these being attained
by the employment of a series of perforated diaphragms, plates, or the like, placed
one above the other in the vessel in which the liquid is treated, by each of which
the streams of gas passing upwards are redistributed in the like manner as by the
lowermost or initial one or ones, breaking up the gas into streams and forming by
each diaphragm a new series of fine jets, so giving the maximum surface contact
and efficiency and obviating the formation of the relatively large bodies or bubbles
of gas above referred to, and the consequent defects; and further, as regards time
contact, the rate of speed of passage of the gases through the liquid is retarded
by the diaphragms or the like, and thus the time which the gas is in contact with
the liquid is rendered greater. Also, the perforated diaphragms are caused to
retain beneath each of them an agitated film of gas, deeper or shallower according
to the circumstances; and the surface being continuously wetted, the gases will act
upon the liquid on this side of the plate as well as on the surface of the liquid
below the film whereby additional surface for contact between the gas and the
liquid is made.
Another effect of the diaphragms or the like will be that in breaking up the
bubbles of gas, new surface will be exposed to the action of the liquid, whereas
when a bubble rises undisturbed from the bottom to the top of the liquid, the
same, or approximately the same particles of gas are continuously exposed to the
liquid, the central core being unacted upon.
The diaphragms are made, preferably, of perforated plates, whilst in some cases
they are made of woven tape or wire gauze. In some cases, however, tapered bars,
ns grate bars, may be employed, the different layers of bars above one another
being placed at right angles to the adjacent layers.
In treating liquids with gases, as when treating sewage, or other foul, or impure
liquids with carbonic acid, i.e. carbonating it (or when oxydizing it by air), a
portion, say at one end or part of the tank or vessel in which the treatment is
being carried on, may be partitioned off, and so arranged that the liquid treated
may flow over the partition downwards, and then under the lower edge of same
into the body of the liquid, so effecting a circulation thereof. Or, in lieu of such
construction, a separate conduit or conduits may be employed outside the tank or
vessel to provide for the circulating or return flow.
In some applications of this invention, where a current of liquor is treated in
passing through a tank or vessel, the liquid is best run in over the uppermost
diaphragm, and passes downwards through the diaphragmns or trays below, while
the gas passes upwards in the opposite direction; thus, the descending body of
liquid is acted upon by the rising streams of gas or air. Where, however, there
is not sufficient head of liquid, or where it may be deemed preferable, the liquid
may be run in at or near to the bottom of the tank or vessel instead of above, in
which case it will pass upwards with the gas through the diaphragms or trays,
being discharged' from the top.
Illustrations of this invention are given in the accompanying drawings, in which
there are shewn diagrammatically in sectional elevation, six modifications of open
top tanks constructed according to, and in which two fluids act according to the
invention.
In the first three figures, the fluid distributing means consist of perforated
diaphragms or plates extending across the entire width and breadth of the tank,
or that portion of the tank in which the method or process is carried on; while in
the three remaining Figures, 4, 5, 6, the distributing plates of diaphragms do not
extend entirely across the tank, or that portion of the tank in which the process or
method is carried on, there being a space left between the wall and one end of
each diaphragm.
In the different figures, the same letters are used to denote the same or
corresponding parts, and the parts which are common to all the modifications are.

page_text: the open top tank, designated a; the diaphragms b, through which both the liquid
being operated upon and the gas which operates upon it, pass; and the diaphragm c,
by which the initial distribution of the gas is effected. In addition to these, there
are the gas and liquid inlets, respectively marked d and e, and an outlet f.
As regards diaphragms, the holes or apertures are preferably small, and the
limit of smallness being governed by the kind of liquid being treated; that is to
say, as fine holes as possible may be used so long as they do not choke up, as the
smaller the holes the greater the efficiency of the apparatus; and these holes,
moreover, may be set closely together.
In the arrangement shewn in Figure 1, the gas enters by the inlet d into the
bottom of the tank at a suitable pressure, and is distributed by the perforated
diaphragm c, passing into the liquid as fine jets.
The liquor to be acted upon by the gas enters the tank a through the inlet e
between the diaphragm c and the lowermost diaphragm b, here the gas intermingles
with the liquid and becomes completely mixed with it, and this mixture of liquid
and gas pass upwards through the first diaphragm b. At this diaphragm the gas
and liquid are distributed, breaking up the gas into streams, and forming a new
series of fine jets, which, with the liquid, pass up and through the holes in the
diaphragm into the space above the lower diaphragm b, obviating thereby the
formation of any relatively large bodies or bubbles of gas, and the consequent
effects; and this action of repeated breaking up and redistribution of the gas and
liquid into fresh fine streams or jets, takes place at every diaphragm. Also, the
perforated diaphragms retain beneath them an agitated film of gas, deeper or
shallower according to the circumstances, and the surface being continuously
wetted, the gases will act upon the liquid on this side of the plate, as well as on
the surface of the liquid below the film, thereby giving additional surface contact
between the gas and the liquid. Other effects produced by the invention, as
regards surface contact, time contact, etcetera, have already been specified. The
liquid operated upon leaves by the outlet f, and the gas passes off from the surface
of the liquid.
The total area of the holes in these diaphragms should be such that gas will
issue through all the holes, so that they all come into use.
The modification shewn in Figure 2, consists in adapting the apparatus to cause
a circulation of liquid within the tank, this modification being more particularly
applicable to cases where the action of the gas upon the liquid must be, relatively,
a prolonged one. This circulation is effected by providing a partition in the
tank a, extending from a point above the bottom of the tank to a point towards
the upper part of same, forming thereby a passage i between the side or end of the
tank and itself. The tank is filled with liquid in this case in any suitable way, and
the gas is distributed through the diaphragm c
as before. The operation, as
regards flow, and action of the gas and liquid in connection with the diaphragms is
the same as that set forth with reference to Figure 1, except that, in this case, the
liquid is driven upwards by the action of the upward flow of the gas jets through
the diaphragms b, and the supply of liquid at the bottom of the tank to the lower
diaphragm b, passes down the channel i, and is the liquid which is forced up
through the diaphragms by the gas jets, and passes over the edge of the partition.
In the modification shewn in Figure 3, the liquid descends in streams, down
through the diaphragms b, whilst the gas enters from below and passes up in
opposing streams to the descending liquid streams. The liquor enters, in this case,
by the inlet pipe e at the top of the tank. Where the cases of the application of
the invention allow, we generally prefer this method of treating the liquid.
In this mode of operation, the downward rate of flow of the liquid through the
openings in the diaphragms, must be less than the rate of the upward flow of the
gas through same, as, otherwise, the gas would be carried downwards along with
the liquid. To carry out this opposing current process, the tank, at one part, is
provided with a partition ', somewhat similar to the partition in Figure 2, and
forming a channel between itself and the wall of the tank. The differential

page_text: upward and downward rates of flow of the gas and liquid are governed by
controlling the rate of discharge from, and inlet of liquor to the tank.
The three modified apparatus or tanks shewn in Figures 4, 5, and 6, correspon,
respectively, as regards their general construction, with the tanks. shewn i
Figures 1, 2, and 3; the modification in these tanks, consisting mainly in providing
a space between the tank wail and the end of such diaphragm, the spaces o
openings in the successive diaphragms being at the opposite ends of the tank.
This modification is more particularly suited for dealing with liquids containing
solid matter in suspension, which might, if the apparatus shewn in Figures 1 to 3
were used, choke up the perforations or openings in the diaphragms. By thes
end openings, however, choking up is avoided, as the solid matters will be caused,
by the current, to be gradually carried up from space to space between the
diaphragms, and without detracting from the gas breaking up and redistributing
action above referred to.
Otherwise than in this respect, the tanks given in Figures 4, 5, and 6, are,
respectively, the same as the tanks shewn in Figures 1, 2, and 3.
In these types
of tanks (Figures 4, 5, and 6) however, the diaphragms or plates may, in some
cases, be inclined upwards in the direction of the current of the rising fluid.
In theɛe modifications, the tanks will be so designed that the major portion of
the air or gas will pass through the diaphragms, and thus the major portion of the
work will be performed by the jets issuing through the perforations, the clearance
or space at the ends of each diaphragm being no greater than is requisite to allow
the solid matters in suspension to pass freely.
As regards the nature of the diaphragms, a simple kind of diaphragm consists
of perforated plates as specified with reference to the drawings, but the invention
is in no way restricted to this type or kind of means for breaking up and distributing
the fluids used in connection with the apparatus; nor is the invention restricted,
as regards the shape or form of tank set forth with reference to the drawings.
As above stated, in treating liquids with gases, the invention has special reference
to the carbonating of sewage effluent after using a lime precipitent to neutralize
the excess of lime which is used in the precipitating process, and to remove the
alkalinity which renders such effluents liable to secondary decomposition. In this
action upon sewage effluent, the carbonic acid passing into the effluent combines
with the hydrate of lime in solution, and forms carbonate of lime, or bicarbonate
of lime. The invention, however, as already mentioned, is not restricted to this.
purpose, but is applicable in most cases where it is desired to mix a gaseous fluid
with a liquid fluid to make one of the fluids act upon the other, that is gas to act
upon the liquid, or conversely, the liquid to act upon the gas. And in the different
applications of the invention, suitable modified forms or constructions of tanks and
apparatus will be employed to meet the varying conditions and circumstances of
such applications.
Having now particularly described and ascertained the nature of this inven-
tion, and in what manner the same is to be performed, we declare that what we
claim is:-
1. The improvement herein described in the treatment of one fluid upon another
in tanks or vessels, that is to say, repeatedly breaking up and distributing the gas
introduced into or passing through the liquid into streams or jets; operating
substantially as and for the purposes set forth.
2. In the treatment of one fluid upon another, the employment within a tank or
vessel in which the treatment is carried on, of a plurality of perforated diaphragms
disposed one above the other, by which the gas passing through the liquid is
distributed and redistributed at each diaphragm; substantially as and for the
purposes specified.
3. In operating upon or treating liquids by gases in tanks with multiple perforated
diaphragms as described, the mode of operation set forth respectively with reference
to the different figures of the drawings.

page_text: 4. The tanks, for use in connection with the treatment of liquids by gases, having
parts arranged, combined, and adapted to operate, particularly as set forth with
reference to and shewn in the different figures of the drawings.
Dated this 22nd day of August 1895.
CHEESBROUGH & ROYSTON,
15 Water Street, Liverpool, Applicants' Patent Agents.