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Патент USA US3073526

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Jan. 15, 1963
Filed Aug. 6, 1959
3 Sheets-Sheet 2
FM. 2
Jan. 15, 1963
Filed Aug. 6, 1959
3 Sheets—$heet 3
J00” G. Gina-saw
Patented Jan. 15, 1963
one of the compartments may be absorbedand normal
operation automatically restored substantially without any
ill effects during continued operation. This is so because
the excess occurring in the supply is diverted or by
5 passed through the aforementioned annular escape pas
sage and through the outer vaned compartment into the
Filed Aug. 6, 1959, Ser. No. 832,008
centrifugal ?eld within the bowl.
7 Claims. (Cl. 233—-28)
More speci?c features lie in detail arrangements of the
This invention relates to centrifuges, and more particu
inlet means relative to the compartmentation of the bowl.
larly to those which are termed solids~liquid separating 10
Other features and advantages will hereinafter appear.
centrifuges for the reason that they effect the separation of
The novel features which are considered as character
the solids suspension into over?ow and under?ow frac
istic of the invention are set forth in particular in the
tions which under?ow cannot readily be handled by a
appended claims. The invention itself, however, both as
liquid-liquid separating type of centrifuge.
to its construction and its ‘method of operation, together
Hence, the invention may be said to relate to improve 15 with additional objects and advantages thereof,pwill be
ments in a solids separating centrifuge such as exempli
best understood from the detailed description of the"
fled in the patent to Glasson No. 2,625,321 which has
speci?cation as follows:
feed inlet means at the top of the bowl, and which differs
FIG. 1 is a vertical sectional view of a solids-liquid
from the liquid-liquid separating centrifuges in that the
separating centrifuge showing the novel bowl construction
solids containing viscous under?ow discharges from the 20 with one embodiment of the compartmentation;
bowl through nozzle means preferably of the reaction re
FIG. 2 is an enlarged detail view of the bowl, showing
sponsive type located in the outer periphery of the bowl,
more clearly the compartmentation in the bowl while also
while the over?ow fraction discharges through the neck
illustrating certain features of operation;
of the bowl. Another distinction in this type of centri
FIG. 3 is an enlarged detail showing the improvement;
John G. Glasson, San Rafael, Cali?, assignor to Dorr
Oliver Incorporated, Stamford, Comic, a corporation of
fuge from the liquid~liquid separating type lies in the 25 and.
provision of controlled recirculation of under?ow material
back through the bottom of the bowl as known for the
purpose of controlling the solids concentration in the un
der?ow as well as to prevent plugging by the solids of the
discharge nozzle means.
According to the invention, the operation and the effec
tiveness of such a centrifuge are greatly improved by the
provision in one end portion of the bowl, opposite to the
overflow end thereof, of novel compartmentation including
FIG.‘ 4 is a fragmentary View of the bowl illustrating
another embodiment of the compartmentation.
The machine herein exempli?ed to embody the inven
tion is of the solids~liquid separating type wherein a cen
30 trifugal bowl it) rotates in a stationary housing 11,
the bowl being rotatably suspended by its shaft 8-1 in
the usual manner from above the housing. The shaft is
connected to the bowl by a hub 10a which has a rim porj
tion 10b of hollow substantially trunco-conical con?gura#
centrifugal vanes cooperating with feed inlet means as 35 tion marginally connected to the associated narrow end
well as with the under?ow return. The propeller vanes
of the bowl and extending inwardly thereof.
of a ?rst annular bottom compartment force feed suspen
The bowl has a constricted top end portion or neck 12
sion into the bowl, while the propeller vanes of a second
provided with an annular lip 13 from which the over?ow
compartment adjacent to the first compartment propel
fraction may discharge centrifugally across an annular
returning under?ow material into the bowl for discharge
in the region of the nozzle means. A controllable supply
of wash water may be introduced into the bowl together
with the returning under?ow with or without under?ow
material through the last mentioned compartment. As a
result of this arrangement, the diameter of the over?ow
discharge neck is minimized thereby attaining high opera
clearance 14 into the over?ow compartment 15 constitut
ing the top portion of the housing provided with an over
?ow outlet connection 16.
The bowl has between its upper and lower trunco-corn'cal
end portions an intermediate peripheral portion of rela
tively large diameter provided with under?ow discharge
nozzles 17. Such nozzles are spaced along the periphery
and are preferably of the reaction responsive type exem
tion, while precluding any short circuit as between feed
pli?ed in the patent to Millard No. 2,695,748. Under
inlet and over?ow due to their being located at opposite
?ow containing solids from these nozzles discharges across
ends of the bowl.
the annular clearance 13 into the surrounding volute por
The invention provides that the two compartments co
tion 19 of the housing intermediate the upper and lower
operate with a central pipe inlet means surrounded by an
ends thereof, then out through under?ow discharge con
annular nozzle inlet means. The feed suspension issues
nection 2ft of the housing. An under?ow return pipe 21
from one of these inlet means into one of the compart
leads from the volute portion of the housing to the bot
ments, while the return under?ow material with or with
tom end thereof for the purpose of re-introducing under
out wash water, or else wash water alone issues from
?ow material into the bowl via the lower end thereof and
tional efficiency at a relative minimum power consump
the other one of these inlet means into the other one of
these compartments. In one embodiment, under?ow re
turn material from the annular nozzle means enters the
one compartment which is outwardly located, while feed
in a manner furthermore to be described.
A discharge valve W1 may be manipulated to control
the rate of under?ow recirculation and thus control the
under?ow discharge concentration in a manner well
suspension from a centrally disposed pipe enters the ad 60 known in the art. A valve W2 is for admitting controlled
joining compartment which is inwardly located.
amounts of wash water into the return conduit 21. ‘A
According to onefeature, provision is made to permit
valve W3 in the return conduit may be operated to throt
by-passing of the- central stream of feed suspension
tle or close the flow through the return connection 21.
through an annular escape passage formed between the
Thus, the return connection may be closed when it is
terminal rim of a central feed inlet pipe and the inner
desired to admit wash water only through valve W2 into
peripheral edge portion of a common annular dividing
the bowl.
wall between the two annular compartments, and the
In the example illustrating the invention the bowl has
width of this annular passage may be adjustable.
a bottom portion specially constructed to provide a ?rst
With this by-pass arrangement, sudden surges in the
or inner annular compartment or in?uent chamber 22
rate of feed supply, or surges in the solids concentration 70 having centrifugal or radially disposed impeller vanes 23,
of the feed, or else foam-or-air lock that may occur in
and a second or outer associated annular compartment
under?ow material from the gap 18 is caused to join the
or in?uent chamber 24 directly underneath provided with
centrifugal or radial impeller vanes 25, which compart
upward stream of return material as a result of the
aspirator effect produced by these nozzle members.
In operation, the feed suspension is forced upwardly
through the distributing pipes 36 into the spaces between
ments have a common annular dividing wall 26 present
ing an inner peripheral edge portion 27. The outer
limitation of chamber 24 is represented by an annular
the separator discs wherein a well-known manner the
wall 100 de?ning an internal hollow space. These mu
tually adjoining in?uent chambers 22 and 24 are therefore
light fraction separates from the heavy fraction, which
fractions discharge through the neck 12 and through the
nozzle 17 of the bowl respectively.
cially shaped annular end wall 10c, and further by the 10 This separation into the two fractions within the cen
structurally de?ned inwardly by the specially shaped rim
portion 10b of the hub, and outwardly by the outer spe
trifugal bowl takes place in a ?uid body having a cylin
drical inner surface de?ned by the effective diameter D1
of the discharge neck 12. Accordingly, the under?ow
this invention provides a bottom feed inlet or feed pipe
material containing the solids discharges through the
28 extending through the bottom of the housing and
nozzles 12 while under the centrifugal pressure of the
surrounded by annular nozzle member 29A whereby re
intermediate substantially ?at partitioning wall 26.
In conjunction with such compartmentation in the bowl,
turn under?ow material passes upwardly into the bottom
portion of the bowl, and thus in the same direction as
the upwardly directed stream of feed suspension. Pref
erably annular aspirator nozzle means 29B in turn sur
round the annular nozzle member 29A whereby any un
mass of ?uid thus de?ned.
' While the diameter of the over?ow neck 12 is thus de
sirably reduced to a minimum dimension, allowing for the
annular clearance around the hub portion 33 for over
20 ?ow discharge, it is noted that the diamter D2 of the cen
der?ow material spilled from volute 19‘ through space
18 into the lower housing portion is picked up by the
tral bottom opening of the lower vaned compartment is
somewhat smaller than the neck diameter D1, and the
diameter D; of the central opening in the dividing wall be
aspirating action of the stream of under?ow return ma
tween the two vaned compartments may in turn be smaller
terial from nozzle 29A. With the upper terminal portion
of the feed inlet pipe extending upwardly through the cen 25 than the diameter D2, and that the inner diameter D.,, of
the discharge end of the feed pipe 28 may in turn be
tral bottom opening of the bowl, the arrangement is such
smaller than the diameter D3. Let it be assumed ?rst that
that, normally the feed suspension from the pipe passes
the feed suspension is continuously supplied at a steady
on upwardly into the upper or inner vaned annular com
rate of ?ow and concentration. When the machine is in
partment 22 which communicates with the interior of the
balanced operation, there results a certain solids concen
bowl, whereas the return under?ow material from the noz
tration in the under?ow according to the setting of the
zle member 29A is de?ected radially into the lower or
discharge valve W1 with flow material then recirculating
outer vaned compartment 24.
at a corresponding rate through the nozzle member 29A
In the present example, the feed inlet pipe has an upper
the lower vaned compartment, while the light frac
end portion terminating in the region of the lower an
nular compartment, that is, a distance somewhat below 35 tion over?ows at a corresponding rate upwardly through
the neck 12 of the bowl. If desired, wash water for
the inner peripheral edge portion 27 of the annular space
the under?ow solids material may be introduced through
or passage P. The arrangement in this instance is such
valve W2 into the return conduit 21.
that the upward stream of feed suspension from the pipe
However, it is one of the features of the invention that
passes across the annular space and against a de?ector
cone 30 so it will fan out as indicated by arrows A1 40 with the improved construction above described, the ma
chine can absorb such temporarily occurring abnormal
to be seized by the vanes 23 of the upper annular compart
conditions as surges in the rate of feed without short
ment thus to be forced through communicating passages
the excess into the light fraction discharge of
23A into the interior of the bowl.
the housing as has occurred where both feed and over
Moreover, the upper terminal portion of the feed inlet
pipe is formed with an annular de?ector lip 31 which has 45 ?ow are located at one end of the bowl. Also, any air
lock or foam lock condition that may develop in the
an overlap O with the inner edge portion of the annular
upper vaned compartment can be absorbed in the sense
dividing wall (see FIG. 3) so arranged that the upper
that the operation of centrifuge is not interrupted. Both
face F1 of the lip de?nes with the inner edge portion of
these conditions are relieved by this invention which al
the annular dividing wall the aforementioned passage P.
The lower face P2 of this lip acts to de?ect the return 50 lows excess amounts of feed to by-pass the upper vaned
compartment 22 as is indicated by the ?ow arrows A3
under?ow material into the lower vaned compartment
24 as indicated by arrows A2, the return under?ow mate
rial being seized by the vanes 24 of this compartment
causing the material to be centrifugally forced outwardly
shown in dotted lines. That is to say, any excess pres
sure momentarily caused by foam or air blockage, or
else by a surge in the feed, will resolve the congestion by
and upwardly through internal discharge conduits or pipes 55 causing the momentary excess to escape through passage
P and thus via the lower vaned compartment and through
the internal conduits 32 into the interior of the bowl where
it is subject to centrifugal separating action even though
Preferably, the centrifugal bowl has an internally dis
delivered into the peripheral space surrounding the stack
posed hollow sleeve portion 33 surrounding the rotor
shaft and rotating with the hub. This hollow hub por 80 of separator discs. Any such abnormal condition is thus
relieved su?iciently until normal operating conditions are
tion itself is shown to have a slightly tapered outer face
re-established. In this way, the feed suspension in any
provided with a plurality of longitudinal radial ribs 34
instance, is forced to pass through the centrifugal pres
over which ?t a stack of vertically spaced conical sep
sure zone within the bowl to undergo separating treat
arator discs 35 well-known of themselves.
Vertical perforated feed distributing pipes 36 may be 65 ment, and cannot possibly short-circuit or escape via the
light fraction over?ow discharge means.
provided to extend through the stack, communicating
The embodiment of FIG. 4 illustrates the fact that
through the passages 23A with the upper vaned compart
the arrangement can be differently arranged or reversed
ment 22.
within the scope of this invention, for example by intro
The annular nozzle member 29A surrounds the feed
inlet pipe 28 to constitute therewith an annular passage 70 ducing return material through the central pipe 28' while
32 at high speed into the region of the feed discharge noz
zles 17.
An outer nozzle
passing feed through the surrounding annular nozzle 28A.
member herein termed the aspirator nozzle member 2913
is concentric with the ?rst nozzle member constituting
Accordingly, in this embodiment, the feed enters the outer
therewith a second annular passage around the ?rst men
pipes 36’, whereas return material enters the inner com
for the return under?ow material.
vaned compartment 22’ communicating with distributing
tioned annular passage, through which any leakage of 75 partment 24’ communicating with internal discharge con
duits 32'. Accordingly, it will be understood that in this
embodiment the under?ow discharge have a return con
nection (not shown) with the pipe 28' including valves
corresponding to valves W1, W2 and W3 in FIG. 1, where
as the feed supply connection (not shown) ‘would lead
into a space of the housing corresponding to space S in
FIG. 1 and thus into the annular space de?ned by the
nozzle 28A’.
Another difference between the embodiments of FIG. 4
and FIG. 1 is noted in the fact that the central inlet pipe
28’ in FIG. 4 is extended‘ upwardly through the opening
in the dividing wall and into the proximity of cooperating
auxiliary impeller vanes V provided on the deflector cone
30'. In this way, the suspension issuing from pipe 28'
is at once seized by the auxiliary impeller vanes V as well
a as by impeller vanes 24a of the inner compartment, with
axis located outside the separating chamber and mar
ginally connected to said rim portion and having an in
termediate centralin?uent opening and constituting with
said hub and rim portion an inner annular influent cham
ber communicating with the separating chamber through
one of said sets of said inleading passage means and
provided with impeller vanes; an outer annular wall sub
stantially coaxial with the rotor axis and having an outer
central in?uent opening and marginally connected to
said intermediate annular wall and constituting with
said intermediate annular wall an outer annular in
?uent chamber communicating with said separating cham
ber through the other of said sets of inleading passages
and provided with impeller vanes; a ?rst stationary con
duit means for supplying feed suspension to the annular
in?uent chamber communicating with said ?rst set of
inleading passages; and a second stationary conduit means
ment, the nozzle members 28A’ and 28B’ are also ex
for supplying control liquid or suspension to the annular
tended upwardly through the bottom opening of compart
in?uen-t chamber, communicating with said second set
ment 22' and thus into the proximity of impeller vanes 20 of inleading ?ow passages.
22a of the outer compartment 22'.
2. The arrangement according to claim 1, wherein said
Furthermore, although it is within the scope of this
rim portion forms a concavity facing outwardly, and
invention where the bowl rotates about a vertical axis, to
said outer Wall forms a concavity facing inwardly and
provide both feed and return inlets at the top end of the
opopsed to said outward facing concavity, and said in
bowl and opposite to the over?ow end thereof, in a pre 25 termediate annular wall is of substantially ?at con?g
ferred embodiment such as herein illustrated, the bowl is
suspended and driven from above and has the novel com
3. The arrangement according to claim 1, wherein said
partmentation together with the feed and return inlets pro
?rst and second supply conduit means are substantially
vided at the lower end opposite the driven end.
concentric with the rotor axis as well as with respect to
Thus, the compartmentation with feed arrangement and 30 one another thus constituting a centrally located inlet
under?ow recirculation in the manner of this invention
conduit and an annular inlet conduit surrounding the
provides improved and highly ef?cient centrifuge opera
same, said centrally located inlet conduit being provided
tion wherein power consumption is minimized, short
with an annular ?ow diverting lip located in a trans
circuiting of feed suspension into the over?ow discharge
verse plane intermediate the plane of said outer central
is prevented, while at the same time operational dis 35 influent opening of said outer annular wall and the plane
turbances producing air lock, foam lock or undesirable
of said intermediate central in?uent opening of said in
a minimum of kinetic energy required. In this embodi
back pressures originated as by feed ?uctuations may be
overcome and absorbed in the continued operation of the
termediate annular wall, said lip having overlapping
relationship with the inner edge portion of said interme
diate annular wall.
4. The arrangement according to claim 1, wherein said
with or without applying under?ow recirculation.
inner in?uent chamber communicates with the separat
As this invention may be embodied in several forms
ing chamber through said ?rst set of inleading ?ow pas
without departing from the spirit of essential character
sages, and said outer inlluent chamber communicates
istics thereof, the present embodiment is therefore illus
with the separating chamber through said divergent con
trative and not restrictive, since the scope of the inven 45 duits.
tion is de?ned by the appended claims rather than by the
5. The arrangement according to claim 1, wherein said
description preceding them, and all changes that fall
inner in?uent chamber communicates with the separat
within the metes and bounds of the claims, or equivalence
ing chamber through said divergent conduits, and said
of such metes and bounds are therefore intended to be
outer in?uent chamber communicates with the separat
embraced by the claims.
50 ing chamber through said ?rst set of inleading ?ow pas
I claim:
1. In a nozzle type centrifuge with under?ow‘ return,
6. The arrangement according to claim 1, wherein said
the combination which comprises a rotor bowl having
rotor shaft is axially secured to said hub by an end screw
trunco‘conically shaped end portions with their wide
cap member provided with auxiliary radial impeller vanes
ends adjacent to each other to constitute an annular sepa- '
cooperating with the vanes in said inner annular in?uent
rating chamber; over?ow means at the narrow end of
the one of said end portions for centrifugally discharg
7. The arrangement according to claim 1, with the
ing over?ow; discharge nozzles mounted upon the outer
addition of a housing structure wherein said rotor bowl
periphery of the separating chamber for {discharging cen
is mounted for rotation by said shaft, said housing struc
trifugally separated under?ow material therefrom; a hub so ture having one end portion providing a receiving cham
having a rim portion marginally connected to and clos
ber with outlet means for the over?ow, an intermediate
ing the narrow end of the other of said trunco-conical
portion providing an intermediate receiving chamber with
end portions, with a ?rst set of inleading flow passages
discharge means for the under?ow, and an opposite end
in the rim portion for introducing feed suspension, and
portion associated with said concentric inlet conduits,
a second set of inleading ?ow passages in said rim por 65 wherein said ?rst and second supply conduit means are
tion for introducing control liquid or suspension, both
substantially concentric with the rotor axis as well as
sets of ‘?ow passages disposed around the rotor axis;
with respect to one another thus constituting a centrally
machine. Also, it will be understood that with the present
construction, the by-pass relief feature may operate either
a group of divergent conduits connected to said second
located inlet conduit and an annular inlet conduit sur
set of inleading passages and having their delivery ends
rounding the same, both conduits extending through the
located in said separating chamber in the region of the 70 respective end portion of the housing, said centrally lo
discharge nozzles for discharging control liquid into said
cated conduit means provided with an annular ?ow divert
region; a rotor shaft extending from said hub axially , ing lip located in a transverse plane intermediate the plane
through said separating chamber and through the over
of the outer central in?uent opening of said outer an
flow end of the bowl and fastened to said hub; an inter
nular wall and the plane of the intermediate central in
mediate annular wall substantially coaxial with the rotor 75 ?uent opening of said intermediate annular wall, and an
annular ‘aspirator conduit surrounding said annular inlet
conduit and cooperating therewith in e?ecting the return
of under?ow spillage into said separating chamber.
References Cited in the ?le of this patent
Coe ________________ __ Mar. 1,
Peltzer et a1. ________ __ Aug. 22,
__________ __. June 4,
Ayres _______________ __ Nov. 29,
193:; 1°
Hall _______________ __ Sept. 17, 1940
Pomeroy ____________ __ Jan. 29, 1957
Denmark ___________ __ Sept. 12, 1949
Flowers ____________ __ Mar. 18, 1947
Andersson ___________ __ Apr. 3, 1951
Glasson ____________ __ Jan. 13, 1953
Hein et a1. __________ __ Nov. 29, 1955
Zachariassen ________ __ June 26, 1956
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