Year: 1885

page_text: We SAMUEL HENRY JOHNSON and CHRISTOPHER CLARKE HUTCHINSON both of
the Engineering Works Stratford in the County of Essex Engineers do hereby
declare the nature of this Invention to be as follows:-
This invention has for its object the rapid separation of matters in suspension in
fluids from the fluids in which they are suspended.
We have found that the rate of subsidence depends on the vertical depth or
thickness of the layer or stratum of liquid through which the subsidence takes
place and that the time necessary to effect the subsidence to the same degree or
proportion is directly in proportion to the depth of such stratum so that the
shallower the stratum of fluid the quicker will the subsidence take place.
In order practically to construct a subsidence apparatus in which the subsidence
may take place from shallow or other strata of fluid we form a subsidence
apparatus in the following manner.
We form the apparatus of a tank within which are mounted a number of inclined
smooth plates or shelves set face to face parallel with one another with narrow
spaces between them.
Each plate or shelf we make to extend from a level at some distance above the
bottom of the tank nearly to the top.
The turbid liquid to be treated is to be passed into the lower part of the tank
and caused to flow upwards between the plates or shelves-care being taken that
the flow of liquid into the machine is so regulated that the velocity of the currents
between the subsidence shelves shall not exceed the rate of subsidence of the
material The maximum rate of flow for the degree of clarification required can
be easily determined by increasing the rate of flow of the liquid through the
apparatus until the liquid passing off from the top of the tank becomes turbid―
the flow should then be gradually reduced until correctly adjusted.
The deposited matters drop on to the inclined shelves and slip gently down
them without break or interruption and in this manner any readmixture of the.
precipitate with the liquid is avoided until it arrives at the point of maximum
turbidity of the liquid at the hopper bottom.
The inclination of the shelves from the horizontal line should be a few degrees
greater than the angle of rest of the precipitate from the material under treatment
Bo that when a certain quantity of the precipitate collects on the said shelves it
will slip down of its own gravity. The shelves should be placed as closely together

page_text: as practicable but care should be taken to set them far enough apart to permit
the matter collecting on the shelves to slip off into the hopper bottom without
obstructing the spaces between them.
The bottom of the tank we form as a hopper or with deep corrugations and draw
off the precipitate from the bottom of the hopper or corrugations either continuously
or intermittently.
In some cases as for example in the precipitation of sewage it is desirable that
the subsided mud should be as concentrated or have as little liquid present in it as
practicable and with this object we provide the apparatus with a pocket or chamber
into which the sloping sides of the hopper bottom guide the precipitate and this
chamber we provide with a sliding or other cover by means of which it can be cut
off from the apparatus whilst the precipitate is being run out.
We would state that we are aware that subsidence apparatus have been
constructed with shelves for the collection of the precipitate and down which such
precipitate could slip but with all the apparatus with which we are acquainted the
precipitate is so discharged from the shelves at such different points that the pre-
cipitate is again put in suspension in the liquid undergoing clarification these
defects we take care to avoid by disposing the surfaces of the plates so that their
inclination shall all be in the same direction and the collected precipitate shall not
fall down freely through the liquid until it has arrived at the point of maximum
turbidity of the liquid.

page_text: We, SAMUEL HENRY JOHNSON and CHRISTOPHER CLARKE HUTCHINSON both of
the Engineering Works, Stratford in the County of Essex, 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 for its object the rapid separation of matters in suspension in
fluids from the fluids in which they are suspended.
We have found that the rate of subsidence depends on the vertical depth or
thickness of the layer or stratum of liquid through which the subsidence takes
place and that the time necessary to effect the subsidence to the same degree is
directly in proportion to the depth of such stratum so that the shallower the
stratum of fluid the quicker will the subsidence take place.
In order practically to construct a subsidence apparatus in which the subsidence
may take place from shallow or other strata of fluid we form a subsidence
apparatus in the following manner.
We form the apparatus of a tank within which are mounted a number of inclined
smooth plates or shelves set face to face parallel with one another with narrow
spaces between them.
Each plate or shelf we make to extend from a level at some distance above the
bottom of the tank nearly to the top.
The turbid liquid to be treated is to be passed into the lower part of the tank
and caused to flow upwards between the plates or shelves care being taken that
the flow of liquid into the machine is so regulated that the velocity of the currents
between the subsidence shelves shall not exceed the rate of subsidence of the
material. The maximum rate of flow for the degree of clarification required can
be easily determined by increasing the rate of flow of the liquid through the
apparatus until the liquid passing off from the top of the tank becomes turbid-the
flow should then be gradually reduced until correctly adjusted.
The deposited matters drop on to the inclined shelves and slip gently down
them without break or interruption and in this manner any readmixture of the
precipitate with the liquid is avoided until it arrives at the point of maximum
turbidity of the liquid at the hopper bottom.
The inclination of the shelves from the horizontal line should be a few degrees
greater than the angle of rest of the precipitate from the material under treatment
50 that when a certain quantity of the precipitate collects on the said shelves it
will slip down of its own gravity. The shelves should be placed as closely together
as practicable 'but care should be taken to set them far enough apart to permit
the matter collecting on the shelves to slip off into the hopper bottom without
obstructing the spaces between them.
The bottom of the tank we form as a hopper or with deep corrugations and draw
off the precipitate from the bottom of the hopper or corrugations either continuously,
or intermittently."

page_text: In some cases as for example in the precipitation of sewage it is desirable that
the subsided mud should be as concentrated or have as little liquid present in it as
practicable and with this object we provide the apparatus with a pocket or chamber
into which the sloping sides of the hopper bottom guide the precipitate and this
chamber we provide with a sliding or other cover by means of which it can be cut
off from the apparatus whilst the precipitate is being run out.
We would state that we are aware that subsidence apparatus have been
constructed with shelves for the collection of the precipitate and down which such
precipitate could slip, but with all the apparatus with which we are acquainted the
precipitate is so discharged from the shelves at such different points that it is
again put in suspension in the liquid undergoing clarification, these defects we take
care to avoid, by disposing the surfaces of the plates so that their inclination shall
all be in the same direction, and the collected precipitate shall not fall down freely
through the liquid until it has arrived at the point of maximum turbidity of the
liquid.
In order that our said invention may be most fully understood and readily
carried into effect we will proceed to describe the drawings hereunto annexed.
DESCRIPTION OF THE DRAWINGS,
Figure 1 is a side elevation partly in section of a subsidence apparatus con-
structed in accordance with our invention.
Figure 2 is a plan, and
Figure 3 is an end elevation of the same.
Figure 4 is a longitudinal section to a larger scale of mechanism for discharging
the deposit from time to time.
Figure 5 is a transverse section of this mechanism.
Figures 6 and 7 are sections of other mechanism which may be used for
discharging the deposit.
In Figures 1, 2 and 3 A. A. is the tank, it is represented as being raised from the
ground to a sufficient height to admit of the mechanism for discharging the deposit
being arranged underneath it. At one end of the tank is a compartment A' to
which the liquid laden with solid matter is admitted by a pipe B. The com-
partment A¹ is shut off from the rest of the tank by an inclined partition C which
however does not extend down into the bottom of the tank. At the other end of
the tank A there is a store chamber D to receive the clear liquid and connected
with the chamber there is the outlet pipe E. The bottom of the tank A is
hopperlike and in it there is a longitudinal aperture; this is closed by a cylinder F
on an axis carried in suitable bearings. The cylinder F when desired can be
turned by means of a hand wheel G and a worm wheel as the drawing indicates.
Within the tank A a series of smooth plates or surfaces H H are arranged
parallel to the partition C and like it not extending in to the bottom of the tank
but so secured to the tank that liquid is unable to pass them at the sides. The
liquid to be treated entering by the pipe B ascends slowly between the parallel
inclined plates H H and deposits upon them the solid matter which previously it
carried in suspension. The clear liquid overflows the upper edges of the plates
and passes into the storage chamber D, from which it is run off either continuously
or intermittently as may be convenient. The matter deposited on the plates H H
slides gently downwards along them and it remains continuously supported by the
plates until it reaches their lower edges and here it is delivered into liquid in the
same turbid state in which the liquid is supplied to the apparatus. The deposit
falls to the lower part of the hopper like bottom together with any deposit which 5
may have been too heavy to ascend in the first instance among the plates; and
there it is received into a longitudinal trough like cavity on the face of the
cylinder F. There are several such cavities around the cylinder and from time
to time the cylinder is turned; thus the cavity which has become full or nearly
full is brought out of the tank and another cavity is brought into position to

page_text: receive the deposit. As the cavity comes round to the under side of the cylinder
the deposit falls out from it or it is removed if necessary. Where the tanks are of
large dimensions and the plates H proportionally wide the bottom of the tank
may have several of these hopper like receptacles, and mechanism for delivering
the deposit at the bottom of each, the bottom of the tank then assuming a boldly
corrugated form.
In the arrangement shown in the Figures 4 and 5 the deposit from the tank falls
in the interior of the cylinder K; when the cylinder is full it is turned round by
gear as already described, and the depozit falls out from it or is removed; the
cylinder is then again brought into position to receive a fresh charge.
In Figure 6 a sliding valve is represented as controlling passages between the
bottom tank and a chamber below, and this chamber is closed at the bottom by a
similar valve whilst the upper valve is open and the lower valve closed the deposit
accumulates in the chamber, and when this is full or nearly so the upper valve is
closed and the lower one opened and the discharge of the deposit then takes place.
Figure 7 shows a similar arrangement except that in place of the sliding valves,
cocks with rotating plugs or it may be of any other suitable construction are
substituted.
Having now particularly described and ascertained the nature of our said
invention and in what manner the same is to be performed we declare that what
we claim is :-
1. A subsidence tank in which parallel smooth plates or surfaces set at a short
distance apart and inclined are provided; and in which liquid charged with solid
matter is caused to enter between these plates at the lower part and slowly to flow
up between them, depositing solid matter as it goes and flowing off in a cleared
state at the upper ends of the plates; and in which also the deposited matter
gradually slides down the inclined plates which support it and prevent it from
being disturbed until it is returned into the turbid liquid admitted to the tank.
2. In subsidence apparatus such as described providing receivers in which the
deposit is collected and which can then be cut off from communication with the
tank and emptied substantially as described.
3. Subsidence apparatus as described and represented by the annexed drawings.
l- נ.י.ת
1
1002
CARPMAEL & Co.,
Agents for the Applicants.