Apparatus for Separating Suspended Solids from Liquids; for Separating Soluble from Insoluble Solid Matters; and for Partially Separating Insoluble Solid Matters of Different Specific Gravities.
Year: 1897

page_text: Date of Application, 10th Dec., 1897
Complete Specification Left, 10th Sept., 1898-Accepted, 26th Nov., 1898
Apparatus for Separating Suspended Solids from Liquids; for
Separating Soluble from Insoluble Solid Matters; and for Partially
Separating Insoluble Solid Matters of Different Specific Gravities.
I, THOMAS HAWKINS PERCY HERIOT, of Pln. Albion, Berbice, British Guiana,
do hereby declare the nature of this invention to be as follows:-
This invention relates to the separation of solid matters from liquids of less
specific gravity in which they are suspended; the separation of soluble from
insoluble solid matters; and the partial separation of solid matters of different
specific gravities.
Primarily the invention is designed for the treatment of saccharine juices in
the manufacture of sugar but it may also be employed in lieu of filtration in
manufacturing, metallurgical, and other operations generally, as for example for
effecting the rapid clarification of fermented and other liquids, for separating bulky
precipitates in the manufacture of dyes, for the treatment of sludge in sewage
works, and for concentrating free gold in finely crushed oro.
As applied to the manufacture of sugar the invention has for object to effect n
more perfect separation of "mud" from limed juice, the "mud" being separated
in a semi-solid condition whilst the juice runs off bright aud clear and can pass to
the "triple effect apparatus without further treatment, thus enabling the sub-
siding clarifiers, re-subsiders, eliminators, and filter-pressers generally employed
in the manufacture of cane sugar to be dispensed with.
"
The apparatus as designed for clarifying juice consists of a centrifugal separator
being a drum with imperforate sides and having an inwardly directed flange with
circular central opening at top and a central discharge opening of lesser diameter
in the bottom, the drum being mounted on a vertical shaft whereby it may be
rotated at a high speed within a stationary outer casing, having openings corre-
sponding to the top and bottom openings of the centrifugal drum. Upon the
shaft, preferably towards the lower part of the drum, is fixed a centrifugal dis-
tributing disc on to which the juice to be clarified is supplied through a removable
feed tube entering the drum through the upper aperture. The juice thus intro-
duced is projected by centrifugal action from the disc towards the aides of the
drum against the interior surface of which the liquid is thus uniformly distributed.
The diameter of the opening in the top of the drum relatively to that of the
drum itself, determines the capacity of the centrifugal for the solid matters retained
therein and may be varied to suit particular purposes or operations but it is
essential that it should be considerably larger than that of the central bottom
discharge opening.
In the operation of the centrifugal the solid matters suspended in a liquid of less
specific gravity are caused by centrifugal action to collect next to the sides of the
drum whilst the liquid forms a film at a lesser radius the liquid gradually accumu
lating until it finally overflows at the lip of the flange around the upper opening
(which forms what may be termed the overflow level of the liquid) and is thence
projected outwards into the enclosing stationary casing by which it is caught and
conveyed away, the action being continuous until the deposited "mud" accumulates
to such an extent as to nearly fill the drum to the overflow level.

page_text: To enable the progress of the operation to be supervised a test tube projects into
the centrifugal drum and has its expanded open end immersed in, and opposed to
the direction of rotation of, the film of liquid a portion of which is caused by its
momentum to flow up through the tube into a glass vessel outside the casing whence
it is returned to the interior of the casing.
The central discharge opening in the bottom is preferably made trumpet-
shaped and the casing has a corresponding discharge opening provided with a flange
rising within the trumpet mouth and of a diameter intermediate of that of the
discharge opening of the drum and the lip of the trumpet mouth in order that any
juice which may drain from the accumulated solid matter as the drum comes to
rest shall be thrown off from the lip of the trumpet mouth and be caught by the
casing and may be collected in a separate receiver whilst the "mud" remaining
adherent to the sides of the drum can be shovelled out through the openings in
the drum and casing without any of it finding its way into the interior of the latter.
The residual juice still contained in the "mud" may be extracted by washing
the "mud" before its removal from the centrifugal, with a small quantity of hot
water introduced in the same way as the juice was supplied and which is caused by
centrifugal action to penetrate the accumulated "mud" and wash out the residual
juice, the wash water and juice being allowed to drain out through the bottom
opening and being separately collected for use over again.
The mode of working is similar for other operations involving the separation of
solid matters in suspension from a liquid of less specific gravity whilst for the
separation of soluble from insoluble solids, and the partial separation of solids of
different specific gravities, the method of subjecting such mixtures previously
deposited against the sides of the centrifugal clarifier, to the action of water or other
liquid introduced whilst the apparatus is rotating would be adopted, the cop-
tinuously supplied liquid in each case Howing out at the top of the drum with the
soluble matters (if any) in solution, leaving the solid matters arranged in order of
their different specific gravities.
101
100
A. M. & WM. CLARK,
Chartered Patent Agents, 53, Chancery Lane, London.
COMPLETE SPECIFICATION.
Apparatus for Separating Suspended Solids from Liquids; for
Separating Soluble from Insoluble Solid Matters; and for Partially
Separating Insoluble Solid Matters of Different Specific Gravities.
I, THOMAS HAWKINS PERCY HERIOT, formerly of Pln. Albion, Berbice, British
Guiana, but now of U'sine Ste. Madeleine, San Fernando, Trinidad, 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 aud by the following statement:-
This invention relates to the separation, by difference of specific gravity, of
suspended solid matters from liquids; to the separation of difficultly-
soluble from insoluble solid matters: and to the partial separation
of solid matters of different specific gravities. Primarily the invention
is designed for the treatment of saccharine juices in the manufacture of
sugar, but it may also be employed in lieu of filtration in manufacturing, metal-
lurgical, and other operations generally, us for example for effecting the rapid
clarification of fermented and other liquids, for separating bulky precipitates in
the manufacture of dyes, for the treatment of sludge in sewage works, and for
concentrating free gold in finely crushed ore.
As applied to the manufacture of sugar, the invention has for object to effect a

page_text: more perfect separation of "uud" from limed juice, the "mud" being separated
in a semi-solid condition whilst the juice runs off bright and clear and can pass
to the triple effect" apparatus without further treatment, thus enabling the
subsiding clarifiers, re-subsiders, eliminators, and filter-presses generally employed
in the manufacture of cane sugar to be dispensed with.
Reference is to be had to the accompanying drawings wherein Figure 1 is u
central vertical section of the apparatus as designed for clarifying saccharine juice,
Figure 2 being a similar view of the lower part of the drum casing illustrating an
alternative form of temporary bottom bearing for the drum shaft. Figure 3 shews
a central vertical section of a modified form of the apparatus as designed for
partially separating solid matters of different specific gravities.
The apparatus consists of a centrifugal separator comprising a drum A with
imperforate sides a and an inwardly directed circular flange a at top and a central
discharge opening B at bottom, the drum being carried by a spider frame C¹ fast
on a vertical shaft C suspended from overhead bearings (not shewn) in much the
same way as the basket drums of ordinary centrifugal machines. The drum is
enclosed within a stationary outer casing D having openings corresponding to the
top and bottom openings of the centrifugal drum A, and upon the shaft (, near
the lower part of the drum, is mounted a centrifugal distributing disc or cone E
on to which the juice to be clarified is delivered through a removable feed tube F
descending within the drum and terminating in a perforated ring f concentric
with the shaft C, the juice thus introduced being projected from the disc or cone
towards the sides of the drum, up which the juice flows, spreading itself in a
film whose thickness increases with the quantity introduced. The disc or cone E
is of a diameter to pass through the central opening at the top of the drum, and
is made removable (for the purpose of facilitating cleaning the inside of the drum)
by being attached, for example, to a sleeve e capable of sliding upon, but adapted
to turn as one with, the shaft C. The effect of centrifugal action (when the drum
is rapidly rotated) is to cause solid matters, suspended in a liquid of less specific
gravity, to sink radially outwards through the liquid and to collect against the
sides a of the drum, whilst the liquid gradually accumulates in depth towards the
centre until it finally overflows at the lip of the flange a (which determines what
may be called the overflow level - of the liquid) and is thence projected into
the enclosing stationary casing D, whence it flows by the outlet D the operation
being continued until the deposited "mud" nearly fills the drum to the overflow
level. The breadth of the top flange a' and the diameter of the drum determine
the capacity for the retention of the separated solid matters and may be varied to
suit particular purposes or operations. But for the separation of suspended solid
matters from liquids the opening within the top flange a should be slightly larger
than that of the central bottom discharge opening B. The latter is preferably
made trumpet-shaped or flaring as at B, and the casing D has a corresponding
discharge opening 1' surrounded by a rising flange of a diameter intermedinte
of that of the throat of the discharge opening B of the drum, and that of the lip of.
the trumpet mouth B' in order that any juice which may drain from the ne-
cumulated solid matter, as the speed of the drum slows down, shall be thrown off
from the lip of the trumpet mouth and be caught by the casing D.
The residual juice still contained in the "mud" may be extracted by washing
the lattor before its removal from the centrifugal, with a small quantity of hot
water introduced in the same way as the juice was supplied, the speed of rotation
being again increased so as by centrifugal action to cause the wash water to
penetrate the "mud" and dilute the residual juice contained therein: this
diluted juice, when the speed of rotation is again reduced, separating from the
"mud" and being drained out through the bottom opening B and delivered by
the trumpet mouth B¹ to the casing D from which it is collected for separate
treatment or for uso over again as a washing medium. Upon the completion
the operation the solid matters remaining adherent to the sides of the drum can
be removed as follows:-
'

page_text: (a) In a semi-dry condition after the drum has stopped, by means of a spade or
scraper so that it falls through the discharge openings of the drum and casing
without any of it finding its way into the interior of the latter;
(b) By means of a strong jet of liquid directed against it from a nozzle whilst
the drum is rotating at a slow speed whereby the mixed solid and liquid matters
are discharged from the lip B of the trumpet mouth into the interior of the
casing and are caught in a separate receiver placed under the outlet D³.
(c) By a combination of methods (a) and (b).
To enable the progress of the operation to be supervised, a test tube G may pro-
ject into the drum, its open end g being immersed in and opposed to the direction
of rotation of the film of liquid, a portion of which is caused by its momentum to
flow continuously through the tube into a clear glass test vessel y' placed outside
the casing and from which it overflows into a catch tray g³ whence it may either be
returned through a pipe to the interior of the casing, or discharged directly into
the clarified juice delivery pipe.
It will have been observed that in order to permit of the discharge of the free
juice remaining in the drum after the supply has been cut off (and before the
residual juice has been washed out of the "inud") it was necessary to reduce the
speed of the drum sufficiently to allow the escape of such free juice by the bottom
trumpet mouth B' and to again raise the speed for the washing operation previous
to the final stoppage for the removal of the "mud." In order to avoid loss of
time due to such alterations of speed, the tube G may be made to serve the purpose
of removing practically the whole of the juice remaining in the drum after the
supply has been cut off, as well as that subsequently washed out of the "mud,”
whilst the drum is rotating continuously at full speed.
To this end the tube G is made telescopic as at ³ and provided with rack and
pinion G or other suitable means whereby the orifico may be caused to move
from or towards the axis of rotation of the drum. Juice having been passed
through the apparatus until the layer of accumulated "mud" has reached the
greatest depth permissible with safety, the supply of juice is stopped, and the
supernatant film of clarified liquid can be removed without reducing the speed
of the drum, by gradually moving the orifice g of the tube G outwards from the
centre of rotation until the effluent begins to show a clouded appearance in the test
glass whereupon the orifice g of tube G is to be returned towards the
axis of the drum, and the hot wash water introduced (the drum still running at full
speed). After being allowed to penetrate the mass of "mud" and to dissolve out
the residual juice, the wash water may be entirely removed, like the clarified juice
by again causing the orifice g of tube G (whilst dipping beneath the surface of
the liquid) to move gradually outward from the axis of rotation. The drum may
now be brought quickly to rest by the application of a brake and the adherent
"mud" removed as already described.
By making the flange a removable and providing flanges of different breadths,
the capacity of the centrifugal and the velocity with which its contents are thrown
off (relatively to any given number of revolutions of the drum per unit of time)
may be varied to adapt the apparatus for different operations or for similarly
treating different materials.
The speed of the drum would depend on the nature of the work to be done. For
the separation of "mud" from cane juice a speed of between 2000 and 3000 revolu-
tiona per minute would be necessary. In order, however, to admit of the charge
of liquid being introduced at the commencement of the operation whilst the drum
1s rotating, without causing dangerous vibration of the drum, it is necessary that
the drum shaft C should run in two bearings one of which might be temporary, its
object being merely to steady the shaft and prevent excessive oscillations whilst
getting up full speed. Both bearings should be made non-rigid by being fixed
in thick rubber bushes so na to have a little play, the lower bearing being situated
either immediately above or below the outer casing, but preferably above, as regards
convenience of removing the "mud." Such a temporary bearing adapted to

page_text: engage with the shaft C immediately above the drum A is shewn at M, Figure 1,
and in plan view in Figure 1' as mounted upon a lever arm M³ pivoted at m' so as
to be capable of being swung aside when not in use, or to be brought by means of
the handle m to bear against the shaft C, a thick rubber bushing is being interposed
between the bearing M and arm M. N (Figure 2) shews an alternative form of
temporary bearing adapted to engage, like a footstep bearing, with the lower end
of the shaft C and mounted upon a screw n with handwheel by means of which
it may be raised into engagement with, or withdrawn from, the end of the shaft.
In this case there may be, in addition to the rubber bushing surrounding the
bearing N, a thick pad of rubber ³ interposed between the screw and the
bottom of the bearing. It will be obvious, however, that the form and mode of
supporting these temporary bearings may be varied. Where the downward pro-
longation of the shaft C passes through the discharge shoot leading from the
central opening D' in the bottom of the casing D, the aperture for the shaft in
surrounded by a raised coaming d³ above which the shaft carries a coned guard e
with lip depending therefrom around the coaming so as to prevent access to the
bearing N of the substances discharged from the casing D. Either of these tem-
porary bearings M or N just described, may be removed from contact with the shaft
when the liqui. begins to flow over the top flange a', the drum then running
steadily on the upper permanent bearing only.
The mode of working is similar for other operations involving the separation
of suspended solid matters from a liquid of less specific gravity. For the separa-
tion of difficultly-soluble from insoluble solids, such mixtures whilst deposited
against the sides of the drum would be subjected to the action of water or other
liquid introduced whilst the apparatus is rotating, the continuously supplied liquid
dissolving out the soluble matters and flowing out of the drum, leaving the
insoluble matters behind.
"
"
For partially separating solid matters of different specific gravities, as for ex-
ample in the operation of concentrating free gold from crushed ore (in which
operation the concentrate is usually the only product worth preserving), the
apparatus may be modified as indicated in Figure which also serves to illustrate
a simple form of apparatus enabling the centrifugal to be worked by hand and
thus adapting it for use in mining districts where a portable machine, suitable for
dealing with small quantities of ore, may be required.
In this arrangement (whether the machine be portable or not) the drum has but
one discharge aperture riz.: that in the bottom, this opening being therefore made
larger than the feed aperture in the top of the drum. The sides a of the drum
slope inwards towards the bottom aperture B for a short distance above the bottom
so as to facilitate the removal of the washed concentrate. The distributing disc E
is mounted just beneath the top flange a of the drum and the mixed solids, sus-
pended in water or other liquid, flow downwards against the sides of the drum, the
heavier solids (such as particles of quartz containing free gold) remaining, in
consequence of the centrifugal action, adherent to the sides of the drum whilst
the lighter particles (on the inner surface of the liquid reaching its overflow
level at the edge of the aperture B) are washed out and thrown off at the lower
lip of the drum so as to be caught by the casing D whence they may be allowed
to run off as "tailings." In this arrangement of the apparatus it is obvious that
the sides of the casing D need only rise high enough to ensure catching the
tailings" thrown off from the bottom lip of the drum.
"
In the portable form of machine more particularly illustrated in Figure 3, the
drum A and disc E are mounted upon a central shaft C supported in two bearings
beneath the drum, and driven through bevel gearing o from a horizontal shaft O
rotated by hand.
In every case, and whether the form of apparatus employed be that illustrated in
Figure 1 or in Figure 3, the disturbing influence of the muddy liquid entering the
centrifugal, upon the already partially separated contents may be greatly reduced
and the capacity of the drum for containing separated "mud" considerably

page_text: increased, by subdividing the drum into a series of compartments superposed in
the vertical direction, by means of shelves or flanges. These are shewn at P
in Figure 1 wherein the drum is shewn as subdivided into three compartments.
These flanges P are similar, in their inclination and in the diameter
of their respective central apertures, to the top flange a and the liquid
on entering the lowest compartment would there deposit the greater
part of its suspended solids before overflowing into the next compa.t-
ment, which would therefore, contain less "mud," and so on the lower compart-
ments becoming successively filled completely, or nearly so, with separated "mud,"
whilst the liquid remains clear in the top compartment for a much longer time than
it could have done in the undivided drum. The flanges P are made removable,
normally resting upon annular ribs p in the drum but being adapted to be raised
successively (when the drum is being cleaned out from above) and stowed out of
the way beneath the permanent top flange a where they may be held by means of
suitable clips, as indicated in dotted lines, at P¹.
These extra flunges as applied to the form of apparatus illustrated in Figure 3,
would be inclined oppositely to those shewn in Figure 1, and their respective
central apertures would, as shewn, be of the same diameter as the bottom discharge
aperture B. In this case, as will be evident, the separated solids will accumulate
first in the top compartment, the clearer liquid being found in the lowest
compartment.
Any slight leakage occurring, when the apparatus is first started, between the
outer periphery of the flanges P and the sides of the drum, would be speedily
stopped by the accumulation of "mud" in the interstitial spaces.
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:-
1. The herein described apparatus for separating the "mud" from limed
saccharine juice in the manufacture of sugar, and for other operations; compris-
ing a centrifugal drum having imperforate sides, a stationary casing enclosing the
drum, and a centrifugal distributing disc or cone, the drum having at top an over-
flow opening for the clarified effluent, formed in an inwardly directed circular
flange, and at bottom a central dischargo opening adapted to permit both the
escape of residual liquid and its collection by the casing; and the easy removal of
the solid matters substantially as specified.
2. In an apparatus constructed as specified in Claim 1 the employment of a test
tube as described, for the purpose of supervising the progress of the operation within
the centrifugal drum and also for discharging the liquid or juices remaining in the
drum after the supply to the drum has been cut off, and without the necessity of
diminishing the velocity of rotation of the drum as specified.
3. The modified form of apparatus especially suitable for partially separating
insoluble solids of different specific gravities (such as are found in pulverized gold
ore) substantially as described and illustrated in Figure 3 of the drawings.
4. The apparatus for separating suspended solids from liquids: for separating
soluble from insoluble solid matters; and for partially separating insoluble solid
matters of different specific gravities, substantially as herein described and illus-
trated in the accompanying drawings.
100
1
1000
A. M. & WM. CLARK,
Chartered Patent Agents, 53, Ohancery Lane, London.