Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
i :~ 63205
The present invention relates to equipment for
separating dispersed systems according to their phases,
and more particularly it relates to a conical tray for a
separator.
The present invention can be used for fine puri-
fication of lubricating oils, fuels and cutting fluids from
mechanical impurities.
A conical tray for a separator is known, including
an internal bead and an external bead on its conical portion,
and radial ribs or partitions on its conical surface.
The number of such ribs is between 4 and 12. The known
conical tray, however~ is not free from certain drawbacks.
Firstly, a particle that has settled on the
conical surface of the tray is acted upon by a hydraulic
force produced by the motion of the liquid in the radial
direction relativeto the surface of the tray, which force
promotes entraining the particles by the flow of the puri-
fied liquid.
Secondly, the provision of 4 to 12 ribs, while
somewhat reducing the rate of entraining the deposited
particles, at the same time promotes turbulisation of the
flow, and, hence, the development of swirls in the area
intermediate two adjacent trays in the stack of the trays,
defined by these radial ribs.
These disadvantages are displayed by all the
conical trays having radial ribs.
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i ~ 632~5
~ here i5 further known a conical tray ~4 a separator,
havi~g an ~ternal bead and a~ i~ternal bead o~ its conical
part a~d projections or lugs o~ these beads.
The co~ical surf acs of this known tray ha~ mounted
thereo~ guide plates~ the geometric pro jection of each
said guide plate onto ~ plan~ ~ormal to the axis of rota-
tion being a poxtion of a mul~ifilar helix. At each point
of this helix the angle between the tangent and th~ Vector
of the velocity of the flow in the direction of the run-off
of the dispersion pha~e equals ~0 to 60. The height oY the
guide plate~ is 0.2 to 0.5 of` the height of the lugs, while
the e~ge of each plate, facing the flow, defines with the
sur~ace of the tray an angle equalling 90. 'l'hi~ structure
of the guide plates has been founa to enhance the trappi~g
of solid particles and to reduce their being entrained by
the purified liquid.
~ owever, with the flow rate or velocity o~ the liquid
and its visco~ity increasing, and with the difference
between the resp~ctive mas~ densities of the particles and
of the purified liquid decreasing, the efficiency o~ the
pu-ilication iq impaired, on account of the settling partic-
les moving about the plates along the flow lines and being
entrained by the purified liquid.
It is an object of thè ~resent i~vention to provide a
conical tray t~J a separator, which, when oparated in a
separator, should rc~u6e the rate of the entraining of
Y`ine particles by the puriYied liquid phase.
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~cr
This aim is attained in a conical ~ray ~ a separator,
havi~g either intexnal and external bGads on the co~ical
portion a~d guide plates secured to either the inter~al
surlace of uhe co~ical part o~ to the extern~l surface
thereof, the plates being arranged so that their projection
onto a pla~e ~erpendicular to the axis of rotation of the
: tray i6 a portion of a multi~ilar heli~ which tray, in
accorda~ce with the invention, the g~uide ~lates are so con-
structed that their height equals the predetermi~ed spacing
of two adJacent conical tra~s in the stac~ of the trays of
f h e s e ~ a fc r
~ e~arator, the surface of the conical portion of the tray
being divided by these guide plates into a plurality of
individual cha~nels adapted eacn to have the fluid flowing
therealon~ in the process Of its separRtion.
It is e~edient that at each point of each guide pla-
te the angle between the Lormal li~e and the generatrix of
the side surface of the tray, i~cluding the same point,
should be in excess oi the angle of ~riction between the
deposited substance and the surface of the t~ay.
It can be also expedient that the edge of each guide
plate, adapted to be enga8ed by the deposit, should be
inclined to the side surface of the tray at an angle selec-
ted within a range from 15 to 30, and that the ratio of
the spacing of adjacent guide plates along the ci~cumferen-
ce of the smaller circle of the tray to the le~gth of its
o ~,~
generatrix should be from 0.1;1 to ~.3:~.
The u~e of herei~ disclosed conical trays in the ~ray
stack of a separator e~ables to si~ificRntly enhance
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the degree of separation o~' dispersion system~, i.e. to
en~ance the de2ree of ~urification of ~uids from impu-
rities~
Other objects and adva~tages of the present inven-
tion snall be made apparent in the followi~g dascIiption
of its embodiments a~d from appended drawin~s, wherein:
FIG. 1 i~3 a lorl~itudinally ~;ectional view oi' a conical
B tray~ a separator, i~ accordance with the invention;
FlG. 2 is a view taken along arrow line A in FIG. 1;
FIG~ 3 is a sectio~al view III-III in ~i~. 2 of the
guide plate of a tray intended ~or separating a heavy
fraction;
FIG. 4 is a sectional view IV-IV i~ ~ig. 2 of the
guide plate of a tray adapted for separating a lightweight
fractio~.
Xe~erring now to the drawings, the1a~ ed conical
tray has a~ e~t~rnal bead 1 (FIG~ 1 and 2) and an internal
bead 2 on the aonical portion 3 ~ integral with guide
plate~ 4 ~hich are ~cd either o~ the internal or
inn~r sur~ace of the conical portion 3 of the tray~ or on
the external or outer surface thereof`. In the embodiment
being described and illustrated in the drawings the guide
plates 4 are o~ the in~er surface o~ the conical portion 3.
Irhe height "h" o~ the guide plate 4 equals the predeter-
mined spacing of two adjacent conical trays (the adjacent
tray 5 is shown in thin li~es in ~IGS 1, 2, 3 a~d 4) when
they are~ssembled into the tray stack of a separator.
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The co~ical surface of the tra~ is divided by these
gui~es 4 into a plurality o~ individual unco~municating
pas~ages adapted each to have the ~luid movin~ ~herealong
in the process of its separation.
The geome-tric projections of the plates 4 o~to a
pla~e perpendiGular to tht axis of rotation deYine a por-
tion of a mul~ifilar helix, as show~ in ~iG. 2. ~he shape
of the helix is defined by the condition that the angle
" ~" between a line normal to the guide plate 4 at any one
of it~ points and the generatrix of the side surface of
the tray, including the same point, ~hall be in excess of
the angle of frictio~ between the sedime~t substa~ce a~d
the surface of the tray.
~ he height "h" of the plates 4 e~uals the abovesaid
predetermi~ed spaci~g of the trays in the stack, i.e.
de~`ines th~ gap between the adjacent trays.
Dep~nding on what fraction is to be separated from the
fluid, i.e. de~ending o~ whether it i8 the heavy or light-
wei~ht fraction, edge~ 6 or 7 i~cli~ed to the surface of
the tra~ at an angle "~ " selected from a ra~ge from ~5
to 30 are made, respectively, on either the co~cave or
convex side surfaces of the plate~ 4.
Should this an~le be short of 15, the wedge-shaped
cha~nel where the sediment is expected to settle occupies
the greater part o~ the chan~el defined between the adja-
ce~t plates 4; furthermore, there a~pears a hazard of this
passage becoming rapidly clogged with the deposit 8; on
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6 _
the other hand, should this angle be in e~ce~s of 30,
its a~ y to re~ain deposited particles is impaire~.
The ratio of the spacing "n" of adjace~t plate~ 4
alo~g the circumference o~ the smaller circle of ~he tray
to the len~th of the latter~s generatrix "l" is within
0 1~4 to 0.~:1. 0 1
When the ratio "n~ i8 short of 0.1~, the dimens-
ion~ of the channels between adj~cent plates 4 become insuf-
ficie~t for the passage of the fluid i~ a laminar flow; on
0.3the other hand, when the ratio is in excess of~k~r, the
size o~` these channels becomes excessive, bringing about
the hazard of swirls and turbulis~tion of the flow.
A ke~ slot 9 made in the smaller circle of the tray
is inte~ded ~or an~ular retaining of the tray when it is
assembled into the tray stack o~ a separator.
The process of separating a fluid is carried out as
follows.
Two adjacent trays are illustrated i~ the drawings.
The phases of a suspension or slurry are separated in the
space between the adjacent trays when the trays have been
assembled into the stack and are rotated.
When a relatively heavy fraction is to be separated
from the fluid being puri~ied, its flow i~ directsd from
~he periphery of ths tray toward the centre thereof. The
fluid containing solid particles enters the inter-tray
space through slits defined between the beads 1 o~ the ad-
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jacent tr~ys and flows therefrom along the channels defined
between the adjace~t pairs of the plates 4. A~ the ~luid
flows through the channels alon~ the co~ical portion ~,
the particl~s the specific gravity of which is higher than
that ol the liqui~ are displaced toward the i~ner side of
the respectiYe tray. Shown for illustratio~ sake in ~IGS 1
a~d 2 is a situation or position A correspondi~g to the
initial stage o~ the separatio~ and a ~ituatio~ or posi-
tio~ B correspo~ding to th0 termi~atio~ of this proces8
with respect o~` a single particle 8. A deposited or settled
p~rticle is acted upon in position B by a ~ydraulic force
"X" the vector of which i~ coincident with the direction of
the ~luid flow, and by the centrifugal force "F". Under
the actio~ of these two forces the particle moves along the
surface of the tray in the direction ol the re~ulta~t f'orce,
toward the co~cave edge 6 of the plate 4, along a path "bl'
(FIG 2), and eventually moves from posltion B into position
C.
This phenomenon enhances the efficiency of th~ separat-
ion, since it promotes the divi~io~ oX the flows of the
fluid a~d of the deposit or sediment, while providing for
the maximum area of their mutual e~gagement.
With the spacing of the trays being relatively small~
~he edge 6 has deposited thereo~ e~en such fine particles
that are practically alwdys e~trai~ed by the flow of the
purified ~luid in separators with the trays of the prior
art.
3 ~ ~ 5
With th e~ge 6 bein~ inclined relative to the surfa-
ce ol the tray (FlG. 3) throughout the entire length of
the plate 4, it defi~ a passa~e where the v~lociti~s
of the ~luid flow sl~rply drop as the height o~ the wed~e-
-shaped passage decreases (whereb~ th~ hydraulic ~orce "Xt'
acting upon a particle becomes small), while the centrifu-
gal force has a normal compone~t "FN" urging the particle
against the edge 6, and a tangential component IIFr" urging
the particle in the directio~ of a dirt collector, opposite
to the direction toward the ducts through which the purified
fluid is withdrawn. 'l'his precludes the particle being car-
ried away by the puri~ied fluid and enhanceæ the conditions
of deliveri~g the deposit 8 into a dirt collector.
Whe~ a fluid is to be se~arated from particles the
specific gravity of which is short of that of the pure flu-
id, the flow is directed from the centre of the trays to-
ward the periphery thereof, with the f`luid entering the
intertray space via slits defined by the i~er beads 2 Of
tho adaacent pairs of the trays, and the inclined edge 7 is
made o~ the convex side of the plate 4 (E`IG. 4), i.e. trays
with this shape of' the guide plates 4 are selec~ed for this
mode of separation.
Separators with trays made i~ accordance with the in~
vention have been f`ound to trap particles as/small as 1 to 3
microns and greater and are suitable ~or replacement of
costly fine-purification filters 9 such as 5-micro~ f'ine
fi~ers the dirt-co1lecting capacity of which is but a small
fraction of' that of tray ~tack separators.
