Purifying Water and other Liquids.
Year: 1887

page_text: Date of Application, 22nd Feb., 1887.
Specification Accepted, 15th Apr., 1887,
Purifying Water and other Liquids.
I JAMES YATE JOHNSON of 47 Lincoln's Inn Fields in the County of Middlesex
gentleman 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 apparatus forming the object of the present Invention is for effecting the
automatic and continuous decantation or clarifying of any liquid holding minute
precipitates or other solid bodies in suspension. For example it may be employed
for the decantation of water holding in suspension precipitates obtained by the
action of a suitable reagent upon Calcareous or Magnesian Salts originally
contained in the water or in other words for the purification or clarification
of water required for manufacturing and domestic purposes. In this case the
decantation apparatus proper is combined either with an automatic preparing apparatus
for the re-agent or with tanks in which the re-agent can be prepared, and regulating
tanks for regulating the supply of water and re-agent.
The object of the Invention is more particularly to effect the clarification, by partial
decantation and complete filtration, but as hereinafter explained, the filtering action is
obtained by means of a species of decantation apparatus, the solid matter deposited in
the filtering surfaces being automatically collected and discharged from the apparatus.
And in order that the said Invention may be fully understood, I shall now proceed
more particularly to describe the same and for that purpose shall refer to the several
figures on the annexed Sheet of drawings, the same letters of reference indicating
corresponding parts in all the figures.
Figures 1 and 2 of the accompanying drawings represent respectively a vertical and
horizontal Section of an apparatus, constructed according to this Invention. The said
apparatus, as indicated in the Drawing is composed of an angular case divided into
compartments. The liquid to be decanted is supplied to the part A, and by means of a
special pouring apparatus is spread over the surface. After descending to the lower

page_text: part, it passes through the pipe 0, 0¹ to the lower part of the compartment B. The
liquid rises in this compartment and when it arrives at m at the upper part it flows
over the
upper edge of the diaphragm m n. A series of tubes may be employed in
place of this diaphragm which directs. the liquid to tubes T perforated at and
arranged in the lower part of a compartment C. The liquid then ascends from these
tubes to the upper end of the compartment C and is finally discharged through an
orifice S.
The
At the lower part of the apparatus there are provided two pockets in which the
doposits and precipitates are collected and from which they can be discharged through
cocks R R'. The sides of the compartment A are inclined in such a manner as to
direct the deposits to one point where they can be discharged through a cock R".
The case A contains several rows of narrow plates inclined towards the side a band
forming a species of grating being arranged baffle wise or in such a manner that the
plates in each row face the openings between the plates in the adjacent rows.
open spaces between the plates extend throughout the whole width of the compartment.
and the widths of the plates and of the spaces are equal. The compartment contains
similar plates inclined towards the side a band melting the side a b on horizontal
lines. These plates are also arranged baffle wise in a similar manner to the plates in
the compartment A but the spaces or openings between the plates are narrower than
the plates and less wide than those in the compartment A as indicated in the plan
Figure 2 and in the diagram Figure 5 which represents a section taken along the
line cd Figure 1. The plates in the compartment A do not join the side a b. an
interval of about one centimetre being left between the side and the ends of the plates.
The side a¹¹ is also provided with inclined plates à arranged between the plates in
the compartment C and serving to direct the currents of liquid under the plates l'.
An ordinary filter F at the upper part of the apparatus serves to complete the
clarification which in certain special cases it may not have been possible to finish
thoroughly in the other part of the apparatus.
λ
The action and principle of this apparatus are as next hereinafter described. The
liquid to be decanted or clarified is charged with precipitated matter when it enters
the compartment A. As it descends through this compartment it deposits a large
quantity of the solid matter being the heaviest and most easily separable on the
plates 1.
If there were no such plates in this compartment there would be no
decanting action because the lower layers or depths would receive the deposits from
the upper layers or depths. By the employment of these rows of plates the liquid is
separated from a large proportion of the solid matter. On leaving the compartment A
the liquid enters the compartment B wherein it ascends. Here a certain amount of
clarification takes place but it is only partial. In fact the deposit is only effected to
such an extent as the rate at which the solid matter descends may be greater or more
rapid than the ascending motion of the liquid otherwise the solid matter is carried
through the compartment.
A second or further separation of the matter in suspension having been effected in this
compartment the liquid being now clarified to a considerable extent arrives at the lower
part of the compartment C in which it ascends until it meets the plates ¹ whereupon
it passes through the openings or spaces (see diagram figure 5) between one row
of plates to the spaces wow in the next row being caused owing to the alternate or
bafflewise arrangement of the spaces and plates hereinbefore described to take a
circuitous or zigzag course as indicated by the arrows in figure 5. It might be
supposed that the liquid would flow in separate veins or currents from one space or
opening such as ☐ Figure 5 to the spaces or openings W. W but this is not what
occurs in practice. It has been shown that between each row of plates there takes
place a species of diffusion of the liquid under each plate the liquid coming through
the opening as at ☐ spreads out over the adjacent plates, passes through the next row,
spreads out again and so on throughout the entire series of plates-The distance
between the plates naturally varies according to the quantity of liquid to be decanted
and the nature of the said liquid. Supposing for the sake of illustration that the
distance between the plates only about two centimetres the advantage of such an

page_text: arrangement is obvious-Owing to this diffusion which takes place between the plates
the liquid is caused to travel over a large extent of surface the plates being very near
together and very numerous so that the rate of ascent is nil or reduced to an absolute
minimum whereby a maximum of depositing action is secured-Morcover as the
liquid circulates in very thin streams (about 2 centimetres thick) the distance through
which the solid matters have to fall is very small-This combination of alternating
plates and spaces constitute in fact a species of filter but it is to be observed that this
filter clears itself automatically.
The solid matters are deposited upon the inclined plates and slide down them until
they fall on to the plates X-They then slide down the surface of the side a¹¹ into
the pocket at the bottom and are removed through the cock R-A similar effect is
produced in the compartment A-The deposits which are arrested on the inclined
plates in this compartment slide first down these plates to the side a band then down
this side to the cock R" The plates are arranged in such a manner that the liquid
arriving at the compartment C experiences as much resistance in passing on this sido
as it does in passing between the plates.
This arrangement presents the following advantages viz.
1. The rate of motion of the liquid between the plates is very slow and the hori-
zontal distance traversed by the liquid is proportionately long.
2. The solid matter deposited on the plates do not slide in the same direction as the
liquid that is being clarified.
3. When the apparatus requires thorough cleansing the compartment C can be
emptied without wasting liquid contained in the compartments A and B and vico
versa an advantage which in most cases is of considerable importance.
4. All the parts of the apparatus are easy of access-The compartments B can bo
cleaned out by opening a man hole in the side P' The upper part of this compart-
ment is placed in communication with the atmosphere by means of a small vent pipe
in order that all plates may be covered by the liquid.
Figure 3 represents a vertical section and figure 4 a plan of a modification of the
arrangement hereinbefore described differing from that arrangement as regards the
plates in the compartment C which in place of being continuous as in the apparatus
illustrated in figures 1 and 2 are divided having spaces between them in a similar
manner to the plates I figure 1 and project to a greater distance from the side of the
compartment Figure 6 shows the arrangement of these plates being a section
taken along the line ef figure 3 This apparatus is provided with two series of rows
of narrow plates with spaces between all inclining towards the middle of the compart-
ment C as indicated in figure 3-The inclined plates being arranged bafflewise pre-
sent considerable resistance to the passage of the water at this part. This arrangement_
is preferable for apparatus of larger size.
When the apparatus is to be employed for the purification of mother waters or
liquids containing substances in solution capable of precipitation or crystallization it
may be combined with an automatic preparer as indicated in Figures 3 and 4 A
preparer of this description may evidently be combined with the apparatus illustrated
in Figures 1 and 2 if desired-The lime or reagent is placed at M figure 3 and the
water which is supplied in a continuous manner to a reservoir H is conducted into a
funnel on the end of a tube K-A current of air passing through a pipe J is delivered
at the lower part of the liquid at the lower extremity of the tube K The ascending
liquid passes through a tube or passage y z (the inlet to which is protected by sheet
metal plate v to prevent the freshly charged lime from getting into the passage) and
ascends in a compartment Q provided with plates where a decanting or depositing
action takes place the deposits being removed at and ¹. The partially clarified
liquid then flowes through a tubes into the compartments A. B and C where the
depositing of the solid matter held in suspension is completed as hereinbefore described
with reference to Figure 1.
In certain cases perforated plates may be substituted for the rows of narrow plates
hereinbefore described or wire or other woven fabrics may be employed for the same
purpose and curved concave or convex plates may be substituted for the narrow flat

page_text: plates illustrated in the drawing. The form of the cases or compartments may
evidently be modified in various ways without affecting the action of the apparatus."
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
First. The general arrangement of apparatus consisting of three cases or compart-
ments A B and C (figures 1. 2 and 5 and the modification thereof illustrated in
figures 3. 4 and 6 substantially as herein before described and illustrated in the accom-
panying drawings.
Second. The arrangement of the plates in the case or compartiment A the open
spaces between the upper row of plates being arranged opposite to the plates of the
row beneath and vice versa for the purpose of obtaining a partial decanting or
depositing action during the downward motion of the liquid the deposits being caused
to slide down the side a band being discharged through a cock R" substantially as
herein before described and illustrated in the accompanying drawings.
Third. The arrangement of the rows of plates in the compartment C (figure 5)
the spaces between the plates (in a horizontal direction) being narrower than the plates
themselves and the rows of plates being arranged with relativoly narrow spaces
betweeen them in a vertical direction in such a manner that the liquid in passing from
one row of plates to another is compelled to spread out horizontally for a certain
distance, the rate of speed at which the liquid ascends and the distance through which
the solid particles have to fall being thus reduced to a minimum the deposits being
received on plates A and sliding down the side a b¹ to the discharge outlet at R¹
substantially as hereinbefore described and illustrated in the accompanying drawings.
Fourth. An apparatus for decanting or clarifying liquids constructed as herein
before set forth and provided with an automatic preparing apparatus or compartment
arranged and operating substantially as hereinbefore described and illustrated in
figures 3 and 4 of the accompanying drawings.
Fifth. The general arrangement, and combinations of parts constituting the
improved apparatus for decanting and clarifying liquids holding solid matter in
suspension substantially as hereinbefore described with reference to the accompanying
drawings.