Note: Descriptions are shown in the official language in which they were submitted.
1091ZO'~
T~e present inventi~on relates to i~mprovements in separ-
ators and more particularl~, relates to irnprovements in methods
and apparatuses for separat~ng certain particles from other par-
ticles in a particle-containing fluid.
Apparatuses are known in t~e art for separating certain
particles from other part~cles - such apparatuses are known as,
for example, centrifugal cleaners, ~ortex separators, and the
` like. Generally, t~e particles to be separated are undesirable
` and o~ten oversized and~or relatively heavy compared to the more
desirable particles. Usually, the particles to be removed con-
stitute a relatively small proportion of the overall weight of
particles present in the particle-containing fluid.
As aforementioned, apparatuses such as vortex separa-
~ tors employed in the prior art for the treatment of the particle-
j containing fluid are well known and generally, the particle-
containing fluid is introduced into a chamber in the form of a
high velocity vortex, the main part of the fluid containing the
desirable particles being withdrawn from one end of the chamber
and the remaining part o~ the fluid containing the undesirable
2Q particles being withdrawn from t~e other endof the cham~er.
The apparatuses receive wide use, for example, in the cleaning
of paper pulp stock and various mineral mixtures.
One problem encountered with the prior art cleaners
is the erosion of the inner wall lining by the particle-laden
fluid which results in high maintenance costs and lo~er separa-
ting efficiency. ~hile certain cleaners are equipped with
linings which can be machined out and replaced, the attendant
costs have discouraged their use.
In addition, in prior artvol~tex separators which use
an elutriation process, a lower plate is normally lowered a
substantial amount so that a re~ect end of t~e separator is open
to the elutriation chamber.
,-
0~
It is an object o~ t~e p~esent inyention to prov~de
improvements in a method and apparatus for cleanin~ a particle-
~ carrying fluid and for separating a particular class of par-
; ticles therefrom.
rn a preferred embodiment of the present invention,
there is provided an apparatus for separating undesired par-
ticles from liquids and liquid suspensions, the apparatus com-
prising a chan~er having a side wall disposed concentrically
about a longitudinal axis, an inlet adjacent one end of said
c~amber, a ~irst discharge outlet in an end wall adjacent said
first end, and a restricted outlet atthe other end of said
chamber, an inlet adjacent said first end for introducing a par-
ticle-laden fluid into said chamber and imparting a vortical
flow thereto, lining means to protect from erosion the inner
: surface of said chamber, and a reject control and closure means
concentric with and into which the restricted outlet at the other
end of said chamber opens, the entrance to said enclosure being
formed by an annular slit-like passage for discharge of rejected
material, an annular enclosure surrounding said slit, the inter-
nal bottom surface of said enclosure being formed by a rela-
tively blunt upright conical abrasive surface having an inverted
conical area therein, the height of said slit-like passage being
defined by the extension of said restricted lower end towards
said surface such that the size of re~ected material passing
through sa~d slit is controlled and the material held at the
opening of said passage, while orbiting around said opening, is
worn by said abrasive surface to a size which will allow the
same to pass through said slit,
In a further embodiment of the yresent invention there
is prov~ded, in an apparatus for separating undesired particles
from liquids and liquid suspensions wherein the apparatus .
109120~
includes a c~ambex havin~ a side wall disposed concentrically
about a longitud~nal axis, an ~nlet ad~acent one end o~ said
chamber, a ~irst discharge outlet in an end wall adjacent said
first end, and a restri:cted outlet at the other end of said
chamber, an inlet adjacent sa~d first end for introducing a
particle-laden fluid into said chamber and imparting a vortical
flow thereto, the improvement comprising separate removable
lining means interiorly of andadjacent to said side wall to
protect from erosion t~e inner surface of said chamber, said
lining means having a con~iguration substantially similar to
that of the chamber, whereby said lining means is adapted to fit
into juxtaposition ~ith said side wall of said chamber. .
In a still further preferred embod;ment of the present
invention there is provided an apparatus for separating unde- ¦
s~red particles from liquids and liquid suspensions, the appar-
atus comprising a side ~all d~sposed concentrically about a
longitudinal axis, an inlet adjacent one end of said chamber, a
first discharge outlet in an end wall adjacent said first end, a
restricted outlet at the other end of said chamber, an inlet
adjacent said first end for receiving a particle-laden fluid and
imparting a Yortical flow thereto, a reject control and closure
means concentric with and into which the restricted outlet at
the other end of said chamber opens, the entrance to said enclo-
sure being formed by an annular slit-like passage for discharge
of rejected material, an annular enclosure surroundin~ said slit,
the internal bottom surface of sa~d enclosure being formed by a
relatively blunt upright conical abrasive surface having an
inverted conical area therein, the height of said slit-like
passage being defined by t~e extension o~ said restricted lower
end towards said surface suc~ that the size of rejected material
passing through sal`d slit ~s controlled and the material held at
105~ZO~.
the opening of said passage, while or~iting around said open~n~,
is worn by said `a~ras~ve surf~ce to a size which will allow the
same to pass through sa~d slit, and centri~ugal throttling means
at the lo~er outlet to reduce t~e ~luid pressure of the rejected
fluid, said throttling means Be.ng adapted to receive an inlet
flo~ whose direction .is parallel to the longitudinal axis of the
chamber.
Having thus generally described the invention, refer-
ence will be made to the accompanying drawings illustrating
embodiments thereof, in wh~.ch:
FIGURE 1 is a s.ide elevational view, partially in
section, of an embodiment of a centrifugal
cleaner incorporating the improvements of the
present invention;
FIGURE 2 is a side elevational view, partially in
section, of a portion of the cleaner of
Figure l; I .
FIGURE 3 is a side sectional view of a component of
the cleaner;
FIGURE 4 is a side elevational view of a portion of
the nozzle; and
FIGURE 5 is a cross-sectional view taken along the
lines 5-5 of Figure 4.
Referring to Figure 1, the device as shown comprises
a headpiece 12, an upper barrel portion 13, a lower conical por-
tion 14, a reject-elutriator 15, and a reject-centrifugal nozzle .
16.
The headpiece 12 has a stock inlet portion 17 designed
to restrict a fluid entering under pressure so as to convert a
considera~le part of the pressure energy into velocity energy,
thereby causing a h~gh velocity vortex indicated by arrows 18 to
lO91ZO~
occur in barrel port~on 13 and to travel down into conical por-
tio~ 14. Inwardly of the headp~ece is a c~l~ndr~cal partition
portion 19, often re~erred to as a vortex ~inder, which also
serves as the central outlet discharge for the cleaned accepted
stock (termed "accepts").
During the travel of the liquid of the vortex 18 down-
wardly, the larger and heavier particles therein, including
those w~t~ a lo~ sur~ace area to weight ratio, are thrown or
moved outwardly to the ~all of the barrel under the centrifugal
and shear forces induced by the vortex, and then travel down-
wardly to the bottom of conical portion 14. ~lso in lower
; conical portion 14, the more central portions of the vortex,
which contain the cleaner, smaller, lighter and relatively high
surface to weight ratio particles, are reversed in direction and
are turned up~ardly to form an upwardly extending inner vortex
as indicated by arrows 20, th~s inner vortex being ~ a diameter
at least su~ficient to fill the ~tlet opening of portion 19; the
velocity of the above vortices ~ill generally be such that a low
pressure gas cone 21 will be formed axially of the device. Such
a gas cone will ordinarily extend upwardly into the outlet por-
tion 19 and at its lower end the cone will ordinarily extend down
to the bottom of the rejects-elutriator 15. Thus, the larger
and heavier particles ~termed "rejects") are thrown onto the wall
of the barrel 13 and cone 14 and slide down over the internal
surface of these portions until they reach 22, the rejects outlet
from the cone and/or the reject inlet to the rejects-elutriator
15, and which consists of an annular slit-like passage designated
by reference numeral 15 and which will be described below in
greater detail.
The design geometry of the barrel and cone portions are
well known in the art, Heretofore, however, previous material
~(~9lZO~
and component-part desi~n o~ these portions h~s ~led to sub-
stantially reduce the h~ ma~ntenance cost and/or the loss o~
cleaning efficiency arising ~rom the erosion o~ the internal
surfaces of ~arrel 13 and conical port~on or cone 14 as the
particles, mentioned a~ove, slide downwardly against these sur-
faces. This is particularly true for applications where very
abrasive particles are included in the heavier particles thrown
against and sliding on these internal surfaces. In some of
the previous attempts the harrel and more generally the cone
~ave been made of erosion-resistant materials, particularly
- ceramic materials such as carborundum and alundum. These mate-
rials, ho~ever, are very expensive and subject to breakage.
Even when less expens~ve materials were used, such as nylon and
steel, there was a tendency to keep these still expensive parts
in use until they failed structurally; in the meantime, however,
the eroded internal surfaces were contr~but~ng to a lowering of
the cleaning efficiency of the centrifugal device due to a tur-
bulence caused by the roughened surfaces.
According to one embodiment o~ the invention, the
internal surfaces of the barrel and/or cone portions can be kept
relatively smooth inexpensively. A detailed application of
such a structure in the present invention can be described as
follows.
Re~erring to Fi~ure 1, ~arrel 13 and cone 14 portions
are combined to form a barrel-cone section yenerally designated
by reference numeral 23 which in turn consists of two parts, an
outer barrel-cone shell 24 and an inner barrel-cone replaceable
lining or sleeve 25.
The sleeve is made o~ an isocyanate resin such as
polyurethane rubber, hereina~ter re~erred to as urethane. Ure-
thane is particularly suitable as an abrasive liner and may be
lO91ZUZ
used as a relati~ely thin slee~e since ~t ~s relativel~ inex-
pensive and can be changed or replaced as frequently as is
necessary to maintain h~g~ cleaning e~iciency. A hardness
range for the uret~ane of about 75A to a~out 75D Durometer has
been found to yield good results. A thickness range for the
lining or sleeve wall of about one-quarter of an inch to three-
quarters of an inch ~ill cover most applications; for a rela-
t~vely small diameter ~arrel, e.g. 4 - 6 inches, a thickness of
3~8 inch is adequate. To prevent theurethane from moving or
extruding at the end of the sleeve, the sleeve is recessed at
both ends as identified by reference numerals 26 and 27 so it
will mate more securely with the other more rigid parts of the
unit and, when necessary, these sections may be reinforced with
steel embedded in the plastic to prevent distortion. Various
parts of the sleeve can be varied in thickness to conform to
the various cleaner s~zes and allo~ use of universal parts for
these varied sizes; this is particularly true at the lower end
towards the re~ects outlet cone tip 28 where a universal reject
unit is used. Other types of ru~ber (e.g. natural rubber) and
resin ~e,g. nylon) can also be used for replaceable sleeve 25.
The barrel-cone shell 24 is sufficiently perforated to
allow any liquid~gas to escape which might ~rm or accumulate at
the interface between the lining and the shell. The perfora-
tions are indicated at 29. When urethane linings are used with
a solid shell 24, liqu~`d accumulates at this interface (probably
due to osmotic action) in suffic~ent quantities to cause the
lining to separate from the shell and to cause blisters. The
extent of this phenomenon varies with the type o~ urethane.
The extent o~ the perforation will ~ary not ~ly with the t~pe of
urethane but also with the degree of bonding present at the
interface. Loose bonding, as would be the case here ~or a
lW12(~
replacement sleeve, ~ould ~e~u~re ~ewer perforat~ons in the
shell as the liquid could travel alon~ t~e ;nter~ace and exit
from the nearest perforat~on or aperture. The upper perfora-
tion lim~t depends essentially on structural strength and cost.
Generally, one to ~our 1~8th inch diameter holes per square foot
have been found adequate. Since the shell provides the main
structural strength it can be made out of any of the conven-
tional structural materials. Fi~erglass has been found to be a
relatively inexpensive and suitable material; per~orated steel
plate and mesh has also been used. If the material used for
the lining or sleeve is not susceptible to the above blistering
phenomenon, the perforations have been found useful for separa-
ting the lining from the shell when the sleeve has to be
replaced. To that extent, perforations greater than 1/8 inch
diameter may be desira~le so that larger, less pointed, devices
can be inserted in the perforations when so used to push and
separate the lining from the shell; alternatively, fluid pres- !
sure could be applied through these holes.
While the conical piece of the main cleaner may have
straight sides or at least straight vertical elements for the
greater part of the cone, a pre~erred embodiment employs a cone
~here vertical elements curve inwardly, that is, towards the
lower portions of the cone, the walls slant more and more dir-
ectly downward than at the upper portions.
The barrel and cone sections may also consist of sepa-
rate parts ~i.e. an outer shell barrel and outer shell cone and
their separate inner sleeves) joined together by a clamp or
flange and the replaceable sleeves too may consist of separate
parts. This i5 of importance mainly when repairing prior art
cleaners or adapting them to the various features of this inven-
tion.
-- 8 --
~09lZOZ
The uniyersal re~ect~elut~iator for this part~cular
embodiment consists o~ the ~ollow~n~ sections~aspects:
(a) a universal flange assemBly, which consists of an end
grip portion 30 which presses or is pressed against
the low~r part of the shell, an elutriating liquid
~- inlet 31 and a sealing rins or collar 32, held by 30
or bonded directly to or screwed into shell 24 these
portions may be separate parts or molded in one part
as s~o~n (and referred to as 33) using conventional
r 10 structural materials, urethane being a preferred
material;
(b) a universal reject-elutriator body or annular enclo- .
sure 34 made preferably o~ urethane of about 70 - 80 .
D and which contains the rest of the elutriating liquid
tangential inlet plus a special chamber recessed in the
upper part ~f the main chamber for blending the elutri-
ating and chamber liquids; alternatively, the elutriating ¦ .
inlet may connect directly with the above-mentioned
special chamber; ¦
(c) a universal dimple or core plate 35, which serves as the
bottom of the chamber and also forms a part of the one
tangential outlet 36 for the rejects; (the plate at the
: same time serves as the top of the reject centrifugal .
nozzle and the top of the tangential inlet 36 to the
reject-centrifugal nozzle 16). The central part of
: plate 35 consists of an outer relatively blunt upright
cone 37 against which the vortical liquid impinges and
an inner, and a more fully central s~all inverted
conical portion 38 which serves to centre the vortex
20 and gas core 21. The inner and outer conical por-
tions may ~e all one piece or ~n separate pieces; they
_ g _
~091~
also ma~ be of separate mater~als or o~ the same
material ~e.g. uret~ane); the inner part, ~or example,
may be made of ceramic. The nature of the material
is important in situations where the abrasive property
of the material can be used to good advantage to
reduce the size of the re~ect material as it orbits
in this gap. The plate also defines or sets gap 22
through which the reject and elutriating flows must
pass. The width of this gap may be changed by remov-
ing a portion of tip 28 or extending it and/or adding
or removing material spacers from the top side of
recess 27.
It will be noted that both the reject flow from the
main cleaner section and the back-flow o~ the elutriating liquid
into the ma~n cleaner section is controlled by the gap or
annular slot 22 between the tip 28 of the conical sleeve and the
surface of the d~mple plate 35. Prior art designs use this gap
only for the flow of the rejects and whenever elutriation is
added the dimple plate is lowered 3 - 12 inches so that the
whole area of the reject end of the conical portion 14 is open
to the elutriation chamber. This latter method of elutriation
was not used because it was felt that elutriation would not work
in a restricted area and~or w~th a restricted inflow/backflow to
the conical section. Applicant, on the other hand, has found
after much experimentation that thisis not so and in addition to
yielding a very compact elutriation chamber, the method and
device allows for a better distribution of elutriating liquid
between the backflow and the reject flow out of the chamberi in
particular, the rejects have a lesser tendency to thicken and to
block the outlets from the chamber, similarly less dilution of
the backflow takes place with the result that the acceptsleaving
- 10 - ~
lO~ZO;~
through outlet 19 have a higher consistency. ~Jower rejects
consistency and higher ~ccepts consistency are both highly desir-
able objectives. Further, th~s compact, relatively inexpensive
design makes it possihle to provide every cleaner with adjust-
able elutriation and reject d;lution all in the same device.
As shown in the drawings, the elutriating liquid
enters tangentially and is combined with the liquid (in the elu-
triator) in a special recessed or arched section in the upper
part of the elutriator chamber. By blending the elutriating
liquid with chamber liquid in a separate area, the turbulent
mixing of the two liquids is minimized thereby preserving the
elutriating effect. However, as mentioned in certain situa-
tions, the tangential aspect may be eliminated and the connec- !
tion may be made directly to this arched section.
In prior art methods involving the use of a core-
trap or plate, the re~ect flo~ leavesthe ~hamber through one out-
let in a direction whic~ is at right angles to the central axis
of the chamber. Applicant, on the other~and, has found that it
is possible and advantageous for the reject flow to leave the
chamber through the outlet in a direction which is parallel to
the central axis of the chamber. The axial direction allows
for a more overall compact design. The tangential outlet or
ramp 36 also serves as tangential inlet or ramp to the reject-
centrifugal nozzle 16 descr~bed below. The size of the single
inlet to the nozzle can be varied by an adjustable orifice to
allow for an adjustment in the rate of flow. With this more
compact elutriator it is important not to use too high a flow
of elutriating liquid as at high inlet flows, turbulence is
created which destroys the elutriating action. One method of
adjusting this flow is to begin with no flow and then to increase
it gradually until an examination shows (a) the rejects fraction
1202
in the accepts is accepta~le or has not increased unduly and (b)
the accepts fraction in the re~ects is at a minimum. A typical
acceptable flow is in the order of one gallon per minute. The
above re~ect-elutriator embodiment is hereinafter referred to as
the "low-flow reject elutriator".
For situations where a higher degree of elutriation
Cat higher flo~s) is dPsired, the re~ect-elutriator may be modi-
fied as hereinafter described and as such it is referred to as
the "high-flow reject elutr~ator".
Applicant's re~ect centri~ugal nozzle 16 consists of
the following sections:
Ca) a universal reject-centrifugal nozzle body 16 prefer-
a~ly made o~ urethane of about 70 - 80 D reinforced
with steel. In the preferred embodiment, a top plate
35, described above under (c), in con~unction with the
re~ect-elutriat~on chamber15, wh~re it serves as the
bottom to that chamber, also serves as the roof of the
inner nozzle. Part of the outer wall of the nozzle
16 contains an openin~ 39 into which the above-
mentioned ramp spills; for ease of manufacture and re-
duced cost, the outer walls and floor of the ramp are
contained in the outer body~cage 40 and the outer sur-
face of the nozzle serves as the inner wall for the
ramp cr channel leading up to opening 39. Thus, the
inner chamber of the nozzle is contained by the bottom
surface of plate 35 and a floor which is spaced from
this surface by, for example, approximately ~" with
walls extending approximately ~ to 2/3 around the cir-
cumference of the chamber and the rest of the circum-
ference consisting of opening 39. Nozzle body 16 is
circular and can rotate within cage 40; in the center
- 12 -
~O91;~()Z
of the floor of the nozzle chamber is an openin~
through which the rejects leave to enter tube 41
which carries the reject flow away from the body
of the overall enclosure. Tube 41 could, if desired,
be connected to a common closed reject header or to a
separate closed conduit or the flow allowed to reject
freely into the atmosphere.
(b) The lower part or cage 40 of the above-mentioned
universal reject-elutriator body 34 encloses nozzle
16; thus 34 and 40 are one piece. The wall of inlet
36, to opening 39 in nozzle 16, is curved such that
as the nozzle is rotated, the wall of the nozzle
approaches or recedes from said wall thereby allowing
the inlet opening 26 to vary in size. Thus, by
positi`oning the nozzle, the flow of rejects to the
nozzle can be controlled ~ simply rotating the
nozzle 16.
~c) Clamp 42, which clamps around the nozzle tube 41 and
rests up against the bottom of cage 40, thereby pre-
vents nozzle 16 from moving upwards under the influence
o~ a vacuum effect which can take place on occasion at
the outlet of sleeve 25.
It will be noted tP,at the flow enters the chamber, is
centrifugally throttled and then leaves the chamber. In a
prior art method, tlle reject flow enters the cham~er through
one inlet in a direction which is at right angles to the central
axis. Applicant has found that it is possible for the flow to
enter inlets in a direct~on which is parallel to the central
axis of the chamber. As was the case for the elutriation cham-
ber, this axial direction allows for a more overall compact and
efficient design with less chance of complete flow stoppage as
well as a better balanced flow pattern.
- 13 -
10~ 0~
Thus, it is seen that reject-centrifugal noæzle 16 and
re~ect-elutriator 15 are contained in the univcrsal overall
reject enclosure or cage 34 - 40 which is joined to the univer-
sal collar 32 by clamp or retainer coupling 43. The enclosure
may be made of conventional structural material (e.g. fiberglass,
epoxy urethane formulat~ons, steel, etc.).
A further feature referred to in the above is the
manner in which the reject material stopped by the annular slit-
like passage or opening 22 between the tip 28 (of sleeve 25) and
surface 37 (of plate 35) can be reduced in size (as it orbits in
the opening) until it is small enough to pass through the open-
ing; this operation or process is effected by making surface 37
an abrasive surface (e.~. by use of ceramic materials). Thus,
the opening can be used to control the size of material allowed
to enter the reject unit and so reduce the risk of the centri-
fugal nozzle becoming plugged.
Looking at the above assembly of reject unit on an
overall basis it will be seen to be a universal integrated
re~ects processing unit. For, once the rejects enter or are
about to enter the unit they are submitted (a~ to a size reduc-
tion process, (b) to an elutriation process (i.e. the accepts
fraction washed out and returned to the main cleaner), (c) to a
dilution process and ~d) to a throttling process (which to a
large degree is "plug-free'~; and the degree to which each of the
four processes are carried out can be regulated by (i) control-
ling the width of gap 22; (ii) the flow of elutriating liquid in
through inlet 31; (iii) the degree of throttling by nozzle inlet
36 and (iv) the flow or flow pressure at the outlet and inlet to
the main cleaner. The examination mentioned above in connec-
tion with the regulation of the elutriating liquid flow can also
be used to regulate the other control points.
- 14 -
109~202
In addition, the unit is easily disassem~led by
merely removing one clamp and sliding the unit o~f the end of
the conical portion of the main cleaner. This particular style
of clamp is sold under tAe trade name "MARMON". It is possible
also to join the lower part of rejects processing unit to the
end grip or collar portion of the cone by a means other than the
present style of clamp, e.g. by providing a screw-thread type
connection.
As mentioned previously, the above processing unit can
be modified so that the elutriating effect can be increased sub-
stantially and this was referred to as the "high-flow rejects
elutriator". This can be done by increasing space 22 to 4 to 5
inches using one of the prior art design parts, i.e. elutriation
~ater in greater quantities is introduced tangentially into a
cylindrical shell-like container into a space shielded by an ex-
tension to the end of sleeve 25, the above universal reject
assembly consisting of dimple plate and centrifugal nozzle is
then moved down and attached to the bottom of the container.
Thus, the advantages of the new reject assembly are combined
with those of the old elutriating assemblyto'form a novel and
more useful reject system.
Viewing the overall cleaner assembly it will be seen
that a number of different sized main cleaner units, comprising
headpiece 12, barrel-cone shell 24 and replaceabIe and adjust-
able sleeve 25, are adaptable to receive the above universal in-
tegrated rejects processing unit. This adaptability is ach-
ieved by using dif~erent sleeves having different thicknesses at
the entrance to the reject processing unit. For example, a
main unit having a 10-inch diameter barrel and a 400 U. S. GPM
capacity could use a sleeve having a thickness of 0.625 inches
at the entrance to the reject processing unit yielding a
- 15 -
lO~lZ(~;~
satisfactory rejects outlet of 2.250 inches in diameter; simi-
larly, for an 8-inch barrel and a 175 U. S. GPM capacity the
thickness could be 0.840 inches and the outlet 1.820 inches in
diameter; for a 6-inch barrel and a 100 U. S. GPM capacity the
thickness could be 1.075 and the outlet 1.350 inches in diameter;
yet in all these sizes the outside diameterof barrel-cone and
sleeve would be the same at the point where the universal rejects
processing unit combines with the main cleaner unit.
Thus it will be apparent from the above that applicant
has provided an overall integrated method and apparatus for sep-
arating particles in such a way as to maximize the efficiency
of the sepaxation while at the same time minimizing manufac-
turing and maintenance costs.
- 16 -
