IMPROVEMENTS IN MACHINERY OR APPARATUS FOR EFFECTING THE SEPARATION OF SOLID BODIES FROM EACH OTHER OR FROM LIQUIDS, AND OF LIQUIDS FROM LIQUIDS
Year: 1881

page_text: PROVISIONAL SPECIFICATION left by Harry John Smith at the Office of
the Commissioners of Patents on the 15th November 1881.
HARRY JOHN SMITH, Ph.D., of Glasgow, in the County of Lanark, North Britain.
"IMPROVEMENTS IN MACHINERY OR APPARATUS FOR EFFECTING THE SEPARATION
OF SOLID BODIES FROM EACH OTHER OR FROM LIQUIDS, AND OF LIQUIDS FROM
LIQUIDS."
This Invention relates to certain improvements in the construction of machinery
or apparatus to be employed in effecting the separation of solid bodies from each
other, or from liquids, and of liquids from liquids.
The improved machine is constructed so that two circular or other shaped
vessels provided with inlets and outlets, which may be protected by filtering
apparatus, rotate together about the same axis, and whose edges, flanged and so
arranged as to obtain close and perfect contact, are brought together or separated
during rotation.
Or the rims or flanges may be fitted closely by means of bolts or clamps, and at
the periphery ports or openings are formed, which may be closed or opened during
the rotation of the machine by devices specially designed for these purposes. And
for certain circumstances a single close or open rotating vessel is used as hereinafter
described.
In carrying out the Invention according to a modification adapted for the
separation of chemical precipitates from fluids, or of bodies or substances heavier
than water from water, or of heavy liquids from lighter liquids, the improved
machine which I employ comprises two vessels, by preference slightly domed or
saucer-like in shape, fitted the one over the other, as a single vessel divided
horizontally, the upper vessel serving as a cover for the lower, with a rubber or
other washer between them if necessary to form a close water-tight joint. In
order to prevent separation of the vessels at the flanges by centrifugal action, the
dome-shaped vessels are connected at their rims or flanges, so that the tops of the
domes are towards each other, or so that the one dome is towards the inner or
concave side of the other, that is to say, the section of the chamber enclosed by
Price 1

page_text: the vessels is either double concave or meniscus. The lower vessel is fitted on a
vertical rotating shaft passing up through it, and on which the upper vessel may
move or slide, or there may be separate shafts on the same axis. The liquid or
semi-liquid substance to be treated is led into these vessels through inlet tubes
from above, or through the central shaft, and the heavier solid particles or liquids
are separated from the lighter liquids by centrifugal action, as hereinafter more
particularly described.
Within the space enclosed by the two vessels round the axis of rotation is a.
cylindrical partition fixed and fitted close to the top or bottom vessel, and having
a closed top or bottom. This partition may be perforated and covered with a
filtering medium, and formed also with channels, or with inner concentric perforated
partitions covered in the same manner if desired for the escape of the filtered
liquid, and the annular compartment enclosed by each partition may be provided
with a stop-cock or valve. Ports or openings with or without check valves may be
formed underneath the partition, protected or not, as found desirable, by filtering
media, leading to a pipe or outlet which passes up or down through the bottom
and top of the cylindrical partition, and which may be fitted with check valves.
From the sides of this pipe or outlet other outlets or pipes are placed which lead
to vessels without the machine. Instead of the partitions referred to, perforated
hollow discs, either or both sides covered with filtering cloth, felt, or other filtering
media, also covered if necessary by perforated plates, may be fitted round the
central shaft or other outlets, and may be of the full internal diameter of the
vessels to intercept solid matter in the outflowing liquids; or these discs may be
made of any suitable filtering substance, such as charcoal. The perforated hollow
discs which act as filters are provided-with-means-for carrying-off-the-filtered-
liquid, either through the central shaft and thence out of the machine, or by means
of an annular or other recess underneath or round the hollow perforated discs, into
which the liquids filtering through the cloth or other material are caused to flow
by centrifugal action or pressure. From the recess round the discs the liquid is
led through pipes leading through the casing of either of the rotating vessels,
preferably the lower, and the liquid may thence be discharged freely, or the pipes
may be connected to a single annular vessel provided with valves or other means
of trapping the liquid.
The mixture of liquids and solids to be treated is led down to the circular vessels
from a supply tank, which consists of an open circular vessel whose centre is
preferably in the axis of rotation, and which may have one, two, or more pipes in
its bottom, and fixed on each side of the axis of rotation. These pipes lead, firstly,
down along lines parallel or nearly parallel with the axis of rotation, and then at
angles to these lines through the partition (within the separating vessels) and its
sides or other convenient part. Or a pipe may be fitted, whose centre and the axis
of rotation are one; or the shaft carrying the vessels may be hollow, and fitted
with ports to form both inlets and outlets.
When the machine is set in motion and a certain velocity is attained, the mixed
solids and liquids are delivered into the circular inlet vessel or supply tank, and
pass thence through the inlet pipes or central ducts into the space formed by the
circular separating vessels, and whose edges must now be in perfect contact.
The solids pass in due course of time to the point furthest from the centre of
rotation, forming annular layers, and the liquid passes through the ports or
openings underneath the bottom of the partition into the discharge pipe, and
thence through pipes finally into a vessel without the machine.
As soon as the solids arrange themselves around the sides of the partition, or on
the central discs, the delivery of mixed solids and liquids is stopped, the flanged
edges of the circular vessel are separated, preferably without stopping the machine,
and through the opening thus formed the solids, as mud or sludge, are thrown from
the machine by reason of centrifugal force. When the discharging is completed
the edges of the vessels are brought into contact again, and the procedure described
is repeated.

page_text: The closing and separating of the vessels while rotating may be effected in a
number of different ways. In a convenient arrangement one of the vessels,
preferably the upper one or cover, is formed with a number of wedges or inclined
planes ranged circumferentially round the upper surface near the rim or edge, and
the other vessel is fitted with small brackets carrying pulleys or friction rollers
immediately over the wedges or inclined can surfaces. These pulleys or rollers
are so arranged in relation to the inclines or wedges that the rollers when over the
wedges may bear on and press down the upper vessel or cover into close contact
with the lower vessel, and by being moved off the wedges may allow the vessels to
move apart on their axis, or open out. The operation of opening and closing the
circular vessels may be performed automatically if desired in the first case by
causing the one vessel fixed to the rotating shaft to be retarded, while the acquired
momentum of the other makes it race or rotate past the first during a part of the
revolution, and thereby frees the wedges or inclines past the bearing rollers, to
allow of the separation of the vessels, while for the closing movement the fixed
vessel may be made to overtake the loosely revolving vessel or cover, and cause
the rollers to mount on to the inclines or wedges to press the rims of the vessels
together.
The extent of the motion of the rotating circular vessels over each other may
be limited by stops, and the extent to which the vessels may be opened will be
likewise limited and maintained in position by suitable devices. The opening and
closing of the vessels may be effected by hydraulic pressure, or the power of a
lever bearing on a collar on the centre of the upper vessel, or by hand, by stopping
the machine, and in this last case ordinary screw bolts or clamps may be used
instead of the wedges and rollers described.
In another modification of the improved machine the dome-shaped vessels are
formed and fitted in a manner similar to that already described, but the flanges are
constructed so as to form a number of ports or openings at intervals round the
periphery, through which the separated solids are discharged, or the flanges may be
left at some distance apart for the same purpose. In these ports, or in the space
between the flanges, stop-valves of suitable construction are fitted, which are
capable of being moved to open or close the discharge ports or outlets either when
the machine is in motion or when standing. These valves may be made in the
form of rollers or wedges closing from the interior against the ports or openings
round the periphery, or as sluices or stop-cocks, facings of rubber, or similar
yielding material, being in general provided to ensure perfect closing. These valves
are operated by any suitable mechanical means, such as by levers, to which the
valves are connected outside, and which may be moved simultaneously by a sliding
collar on the rotating shaft, or the valves may be closed and opened by hydraulic
pressure, either through levers or direct by means of rains or plungers connected
to the valves, and fitted in barrels carried within the vessels, or outside the vessels
according to the position of the valves, or by means of cam surfaces bearing on
the back part of the valves.
In a modified construction of this arrangement of machine, in which the solids
are discharged through ports, and the vessels do not require to be separated for this
purpose, a considerable thickness of filtering cloth, felt, or similar material covered
by perforated plates is interposed between the flanges of the vessels, and the ports
or openings for the discharge of the solids are formed in each vessel on each side
of the filtering washer, the closing valves of these ports being made to bear on this
yielding cushion if desired. This construction of machine may be so modified that
the vessels may separate during rotation to discharge the solid material, or a single
vessel may be used and covered at either or both ends with a washer or thickness
of filtering material suitably protected, or a number of such open vessels may be
arranged, one over the other, with washers of filtering material between each
vessel, provision being made in each case for discharge of the solids, either by
separating the vessels and filters from each other or by means of valves. The felt
or other material between the flanges may extend inwards to the centre of the

page_text: vessels and also outwards beyond the flanges, and will serve as a filter for the
escape of the liquids, which will exude through the filtering material and be driven
off by centrifugal action; while the filtering substance being laid flat in the plane
of rotation there will be no tendency for the solids to be forced into the pores of
the filter by centrifugal action.
In certain processes, wherein, for example, chemical re-agents are employed
within the machine to facilitate precipitation, or to promote chemical processes, or
in the treatment of sewage, or substances used in certain manufactures, such as
those used in soap making, as, for example, palm oil, the separation of the various
products obtained, or the separation of liquids from liquids of different specific
gravity, may be effected in machines of the kind described, means being provided
when necessary whereby the materials within the vessels may be stirred or
agitated.
Stirrers or agitators fitted within the vessels may be actuated by means of
gearing from a fixed central shaft within the hollow rotating shaft, or the spindles
or axes of rotation of the stirring or agitating devices may be carried through
stuffing boxes in the shell of either of the vessels, and be fitted with toothed or
friction gearing operated by means of an internal geared or friction wheel. Such
gearing may be readily arranged so as to be put out of action when desired during
the rotation of the vessels, or the agitation of the materials within the vessels may
be effected by means of jets of steam admitted through the inlet, outlet, or other
openings in the vessels; or when the action of steam might be prejudicial, compressed
air or other fluid may be injected for the same purpose. Means may also be
provided whereby a jet or jets of steain, air, or other gas, or fluids or solids, may
be injected into the vessels to facilitate the removal of-the-liquid-from-the solid
matter or sludge after separation by means of centrifugal action, or to effect
chemical decomposition.
The mixture of solids and liquids to be separated in closed machines, as
described, are generally with advantage operated upon under pressure, or otherwise
the liquid matter may be pumped out through a filtering medium.
The action of separating the liquids and solids and of the filtering arrangements
may be facilitated by pressure of steam, or of compressed air and steam, or
compressed air of considerable pressure introduced by the inlet or other openings
may also be used to force out the solids from the vessels after separation from the
liquids and to clear the filters.
When solids which are lighter than the liquids in which they are immersed are
to be separated from such liquids within the machine the vessels are formed with
perforations or openings round the periphery, or on the upper and lower shells or
casing of the vessels near the periphery, such perforations or openings being covered
with filtering media. The rotation of the vessels when filled will force the heavier
liquids towards the periphery, while the lighter solids will aggregate round the
centre until the vessels are filled, when the supply of mixed solids and liquids will
be stopped, and the vessels may be opened or separated during rotation to cause
the solids to be thrown out by centrifugal action, or means may be provided
whereby the solids may be removed as they accumulate or after complete separation
from the liquids through the central shaft or openings close to it.
By use of the filtering arrangements hereinbefore described, and where the liquid
is allowed to escape otherwise than through the central shaft of the machine, as by
pipes or chambers extending radially outwards, there is a tendency on the part of
the material within the machine to settle in alternate zones or rings of liquid and
of solid or semi-solid matter, the positions of the solid zones being in general
determined by the extent to which the outlet pipes for the liquid are carried out
from the centre of the machine, and by the use of filters either arranged
horizontally or as vertical annular partitions, as described, or as radial partitions;
it may be found impracticable to withdraw the liquid without disturbing tho
solid zones.
To obviate the formation of such zones in some cases, and in other
cases to take advantage of such formation, I withdraw the liquid from the filters

page_text: or partition through pipes direct or through a central chamber, preferably on the
bottom of the lower vessel, fitted with pipes, these pipes in each case being so fitted
that the distance of their outlets from the centre may be varied at will during
rotation or otherwise. In this way the centrifugal action on the material within
the machine, and on the liquid escaping through the central chamber and pipes,
may be equalised, or a greater or less tendency may be given to the solids to settle
towards the periphery of the vessel. When alternate zones of liquid and solid
matter are formed, I also introduce movable pipes fitted with cocks or valves, or
fixed pipes provided with movable valves by which the liquid may be drawn off
from the closed vessels at any desired point. Such pipes may be carried through
the shell of one of the vessels and be kneed or bent within the vessels, so that by
turning the pipe its open end may be brought within the liquid zone.
These pipes for withdrawing the liquid in this manner are by preference covered
with cloth or other filtering medium, but in some cases such pipes may be covered
with perforated plates only to draw off the semi-liquid matter.
In a modified arrangement of the machine for separating solids and liquids, a
single rotating vessel is used which may be close or open above, somewhat like an
ordinary centrifugal machine.
The outer periphery of the vessel is either made solid or perforated, and covered
with filter cloth or other filtering medium, and a central annular partition is fitted
within the vessel, also perforated and covered with a filtering medium. From the
central chamber formed by this annular partition an outlet or outlet pipes (which
may be fitted with cocks or valves) are led without the machine, and these pipes
are fitted so that the radial distance of the discharge outlets from the centre of
rotation may be varied at will during the rotation of the vessel, as, for example, by
telescoping or by turning their ends inwards or outwards.
When the machine is set in motion the rotation of the vessel will cause a layer
of the heavier solids to aggregate round the periphery of the vessel, and if the
outlet pipes from the central chamber be carried out radially to any distance
beyond the position of the annular partition, a layer of solid matter will also form
round that partition, leaving an annular zone of the lighter liquid matter between
the zones of solids. Pipes or openings covered with filtering media, and the
positions of which may be varied, inay be fitted in the shell of the vessel; or when
the vessel is an open one, siphon pipes may be led from the vessel to carry off the
liquid as it is separated in the intermediate zone between the layers of solid matter.
When the solids to be separated are lighter than the liquids, the order of formation
of the zones will be reversed, that is to say, the liquids will separate towards the
outer periphery and towards the annular partition, while the solids will be left as
an intermediate zone. The annular partition and outer shell or periphery of the
vessel being perforated and acting as filters will carry off the liquid as it separates,
while the zone of solid matter will continue to form, when there is a continuous
supply of mixed solids and liquids to the machine, until the vessel is filled.
Stationary casings suitable to the particular construction of machine are fitted
to surround the rotating vessels, such casings being in general constructed of sheet
metal and in the form of truncated cones, to direct downwards or otherwise the
material which is discharged from the vessels.
When solids are to be separated from solids of different specific gravity, the
machine is so modified as to collect the lighter bodies near the axis of rotation.
For instance, if a mass of cinders, ashes, and small unburned coal are to be treated,
the upper vessel or cover is made open above or formed with cross bars carrying
an outer lower rim, which is formed with ports or openings to allow the lighter
substances to be thrown out, and instead of the cylindrical partitions being closed
at the top and fixed to the top circular vessel, as described in the first inodification
of machine referred to, there is an open vessel with a perforated bottom fixed
round the axis of rotation and also rotating, which vessel can be raised to the ports
in the rim and lowered at will during rotation. The machine is filled with water
or other fluid, the mass under treatment is thrown into the machine, the lighter

page_text: bodies, that is, the unburned or partially burned coals move towards the centre of
rotation, and by raising the vessel with the perforated bottom, are thrown by
means of the centrifugal force beyond the machine. The edges of the vessel are
then opened, and the cinders, and ashes, and water are thrown likewise out of the
machine.
In machines of the larger sizes of any of the kinds described, the lower of the
rotating vessels may be supported by means of wheels or rollers placed either at
the periphery or intermediately between the periphery and the axis of rotation, or
in both positions. These wheels or rollers may either be carried in bearings
connected to the vessels or in fixed bearings, and the motion of rotation of the
vessels may be derived from motion imparted to such carrying wheels if desired.
When the machine is driven by means of wheels or rollers on which the vessels
rest, a central space, which in the other constructions of machines is occupied by the
driving vertical shaft, may be left, as little or no separating action takes place at
the centre, in which case the vessel or vessels will be of an annular form, and the
central space may be conveniently utilised for the withdrawal of the liquids or in
such machines as stirrers or agitators are required the operating gearing or
mechanism for driving such stirrers may be fitted within the space.