Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
The present invention reiates to industriai filters
comprising filtering cells and a distributor collecting and dis-
tributing fluids from the cells, said distributor comprising
essentially a distributing part and a collecting part sliding
relative to one another with a cyclic movement, the collecting
part being divided into chambers and compartments bounded by
partitions, said compartments communicating with one or a plural-
ity of intake and discharge devices for gases and liquids, the
chambers being isolated and communicating each with a sucking or
pressurizing device, the collecting part comprising in communica-
tion with each cell, cavities that open in sequence during the
cyclic movement, in front of each one of said compartments and
chambers in such a way that during each cycle, each cell communi-
cates in sequence with each one of said compartments and chambers.
Said distributing part divides or distributes the fluids from the
~; cells in the succeeding compartments and chambers of the collect-
ing part where they collect to be directed towaras various dis-
charge circuits.
This application is a divisional application of copend-
ing application No. 262,957 filed October 7, 1976.
In the known cell filtèrs of said type, for example
,.~
those filters which are the object of U.S. Patents 2,684,158 and
3,072,136, during the filtering of some pulps, heavy crystalliz-
ings and scalings can be formed inside the filtrate circuits and
possibly in the washing water circuit, which requires repeated
stoppages and cleanings of the filters.
- - An essential object of the invention lies in obviating
- said drawback.
In copending application No. 262,957 there is claimed
an industrial filter comprising filtering cells and a distributor
for collecting and distributing fluids from the cells, said dis-
tributor comprising essentially a distributing part and a collecting
a3~ ,
10'~ 8
part sliding relative to one another with a cyclic movement and
being in contact with one another by means of a sliding gasket,
the collecting part being divided into chambers and compartments
bounded by partitions, said compartments communicating with one
or a plurality of intake and discharge devices for gases and
li~uids, the chambers being isolated and communicating each with
a suction or pressurizing device, the collecting part comprising
in communication with each cell, cavities that open in sequence
during the cyclic movement, in front of each one of said compart-
ments and chambers in such a way that during each cycle, each
cell communicates in sequence with each one of said compartments
and chambers, in which each one of said compartments is provided
on the one hand at the bottom thereof with at least ~ne liquid-
discharge outlet lying substantially below that ievel where the
cavities open and on theother hand, above the liquid top level,
with at least one passageway towards a gas-sucking device in such
a way as to suck said gases while causing the gases and liquids
~: to separate and go along different paths inside the compartments,
means being provided to return ~o the original compartment those
- 20 li~uids which might have entered said passageways so as on the one
hand, obtain at the distributor outlet, liquid-free gases and on
the other hand, collect through the discharge openings only liquids
which are substantially free from undissolved gases.
According to the present invention there is provided an
industrial cell filter comprising a series of filtering cells as
well as a distributor for collecting and adjusting the distributing
of those fluids passing through the cell filtering surface, each
cell having a planar filtering bed comprised essentially of a
filtering cloth bearing on a rigid apertured support retained above
the cell bottom to leave a free space for the flowing of the fluids
passing through said cloth, said bottom slanting towards a drain
channel collecting said fluids, said channel itself slanting with
10~ 8
the iow end thereof opening into a discharge duct connected to the
distributor, in which guide members are provided to fractionate,
divide and direct said fluids as they enter the drain channel into
substantially parallel adjacent streams flowing to said discharge
duct.
Thus according to the invention, each one of said compart-
ments is provided on the one hand at the bottom thereof with at
least one liquid-discharge outlet lying
' 10
. 20
~'
- 2a -
~0'~131L3~S~
substantially below that level where the cavities open and on
the other hand, above the liquid top level, with at least one
passageway towards a gas-sucking device in such a way as to suck
said gases while causing the gases and liquids ~ sepa~e and go
along different paths inside the compartments, means being pro-
vided to return to the original compartment those liquids which
might have entered said passageways so as on the one hand, obtain
at ~e d~tr~utcr outlet, liquid-free gases and on the other hand,
collect throu~h the discharge openings but liquids which are
substantially free from undissolved gases.
This invention has also for object improvements
to filter cells with horizontal iltering surfaces so as to insu-
re the fast and smooth filtering, flowing and discharging of the
liquids and gases collected inside said cells , with a view to
improving the efficiency of the washings both of the filter cake
and of the filtering bed and the cells proper, and to avoiding or
at least minimizing in this way the scale-formations in those
filter parts also.
Said filters comprise a series of filtering cells
with each such cell having a filtering bed which is essentially
comprised of a filtering cloth bearing a rigid on apertured
support which is retained above the cell bottom in such a way
as to leave a free space ~r the flow of those fluids that go
through said cloth, said bottom slanting towards a drain channel
~which collects said fluids, said channel slanting in turn with
the low end thereof opening inside a discharge duct connected to
the distributor, said filters having for characteristic that gui-
- de members are provided to ~ractionate, divide and direct said
fluids as they enter the drain channnel into substantially paral-
lel ad~acent streams flowing to said discharge duct.
J 0!3~
This i~ven~ion further provides in the cells,
particular fastening means which are common bothto the filtering -
cloth and the support thereof, said means allowing to enlarge the
useful area o~ the filtering cloth, by improving also the drai-
ning of those filter cake particles that lie along the ci.rcumfe-
rence of the filterlng bed. Said means further allow to replace
rapidly and easily the cloths .
- For this purpose according to the invention, the
cloth edges are folded-back inside the cell and upwardly against
the side walls thereof, means being provided to secure in a remo-
vable and vacuum-tight way said cloth edges against the inner
walls and to fix simultaneously said support inside the cell, said
: . means comprising rods formed by two diverging lengthwise arms
enclosing an obtuse angle and having two continuous ~gthwise pro-
jecting edges, said rods being arranged inside each cell along
the filtering surface circumference thereof, said folded-back
cloth edges being retained between two gaskets from elastomer ma-
terial, the rod lengthwise projections bearing on the gaskets
which lie relatlve to the folded cloth edges, on that side oppo-
- site the inner side walls,fastening members such as bolts acting
on the center rod portion lying.at the junction of said arms so
as to press the cloth and the gaskets against the side wa~s, while
trying to spread resiliently the projections engasing the cloth,
in such a way that the lower edge also bears on the cloth-support
edges and secures same inside the cell.
The improvements brought about by this invention
comprise various devices which speed -up substantially the fil-
tering, the flowing and the separate collecting of the various
fluids, which allows the use of higher speeds and flow rates which
by reducing the cycles, shorten the dwelling times ~ r the fluids
.
- 5 - ~ O ~
inside the filters and the ducting thereof and allow to wash
amply and efficiently the filter inner members to thus minimize
on the one hand the action of the positive scaling factors and
enhance on the other hand the scale-destroying factor action.
As the output per filter unit area is substantial-
ly increased relative to the known filters, due to the faster
filtering with shorter cycling and enhanced inner flow, filters
arranged according to the invention will be smaller for a given
output capacity, thus with a correspondingly reduced cooling area,
wh~h results in a corresponding lowering of the scale-formation
rate.
Moreover the application of all said improvements
makes possible and economical the construction and use of swin-
ging-cell filters with a very large surface area, wich brings
substantial savings in the capital costs for the still larger
production units which are a feature of modern industry.
Other details and features of the invention will
stand out from the following description given by way of non limi-
tative example and with reference-to the accompanying drawings,
in which :
Figure 1 is a diagrammatic perspective view of a
rotating filter with swinging cells which is provided with a
known conventional distributor.
Figure 2 is a diagrammatic view of such a filter.
- Figure 3 is a part plan view of the filter shown
in figuPe 2.
Figure 4 is an elevation view in section along line
IV-IV in figure 5, of a first embodiment of a distributor accordinn
to the invention which is to replace the conventional distributor
of the rot~ting cell filters as shown in figure 1 by reference
10.~3~ 8
~umerals 100, 110 and 111.
Figure 5 is a view in cross-section along line
V-V in fi~ure 4.
Figure 6 is an elevation view in section along
line VI-VI in figure 7, showing a second embodiment of a distri-
butor according to the invention.
Figure 7 is a view in plan and in cross~section
along line VII-VII in figure 6.
Figure 8 is an elevation view with parts broken
away,ofa third em~odiment of- a distributor according to the
invention.
Figures 9, 10 and 11 are sequential part plan
view along lines IX-IX, X-X a~ -XI-XI in figure 8.
Figure 12 is an elevation view with parts broken
away, of a fourth embodiment of a distributor according to the
invention.
Figure 13 is a plan view with parts broken away
and in cross-section along line XIII-XIIIin figure 12.
Figure 14 is an elevation view with parts broken
away along line XIV-XIV in figure 15 relating to a! fourth em-
bodiment of a distributor according to the invention.
Figure 15 is a plan view in cross-section along
line XV-XV in figure 14.
Figure 16 is an elevation view ln cross-section
along line XVI-XVI in figure 17, showing a sixth embodiment of a
distributor according to the invention~
Figure 17 is a plan view in cross~section along
line XVII-XVII in figure 16.
Figure 18 is an elevation view in cross-section
along line XVIII-XVIII in figure 19 of a first embodiment of a
~0'~9~8
-- 7 --
detail of a distributor according to the invention.
Figure 19 is a plan view in cross-section along
line XIX-XIX in figure 18 of the same detail.
Figure 21 is an elevation view in cross-section
along line XX-XX in figure 21, of a se~ond embodiment of the
same detail of the distxibutor according to the invention.
Figure 21 is a part plan view along line ~XI-XXI
in figure 20.
Figure 22 is a diagrammatic elevation view in
cross-section along line XXII-XXII in figure 23 showing a cell
completed with dividing and guiding members for the filtrate
flow.
Figure 23 is a plan vlew a~ong line XXIII-XXIII
in figure 22.
Figure 24 is a cross-section view along line XXIV-
XXIV in figure 22.
Figure 25 is an elevation view in cross-section of
a detail of the cell shown in figures 22 to 24.
; Figure 26 is a part diagrammatic view in cross-
section along line XXVI-XXVI in figure 27 showing a first parti-
cular embodiment of the means for fastening the filtering cloth
and supporting same ~side a filter cell according to the inven-
tion.
Figure 27 is a side view along line XXVII-XXVII in
figure 26.
.
Figure 28 is a part cross-section view along line
- XXVIII-XXVIII in figure 29 showing a second embodiment of ~ filter
cell provided with special means for fastening the filtering
cloth and supporting same inside the cell.
; Figure 29 is a side view along line XXIX-XXIX in
- 8 -- 10~9~8
figure 28.
In the various figures, the same reference nume-
rals pertain to similar elements.
Even if this invention relates in the main parts
thereof, to cell filters in the broadest meaning thereof, it does
pertain more particularly as a whole, to improvements to rotating
filters with cells the filtering surfaces of which should be flat
and horizontal during the supply, filtering and washing steps,
and notably to such filters the filtering cells of which swing
at the end of the.filtering cycle to let the filter cake formed
on the filtering surface, fall by gravity.
The general principle of such filters is known and
has been the object of a plurality of Patents such as U.S. Patent
2,684,158 and French Patent 999,442.
~ Such filters comprise a series of fil~ering units
which are generally called "cells", which undergo separately in a
discontinuous way, the succeeding steps of filtering, washing,
various special treatments, discharging the cake formed on the
filtering surface, washing and drying the cells and the filtering
cloth. All said various s~ps are reproduced during each movement
cycle, all of these cycles ~omprising a continuous general pro-
cess which is integrated into a filtering line.
An example of such a filtering line is shown dia-
grammatically in figure l while other details of a correspon-
ding filter have been shown diagrammatically in figures 2 and 3.
Such a filter comprises essentially :
a) a rotating frame 300, comprised of circular beams 310 joined
by radial connecting arms 320 bearing cells 200 by means of bea-
rings 230, said beams rotating on two series of rollers 410 made
fast to the foundations and arranged in two concentric circles,
- g - lO~l9t~8
the movement remaining centered due to the action of centering
rollers not shown;
b) a power unit not shown which conveys the movement to the ro-
tating frame through a gear rack secured to one circular beam
310;
c) guide levers 213 for the cells bearing two rollers 211, 212
which run on rails 710-720 made fast to a circumferential skele-
ton 600;
d) distributing troughs 810 and 820.hanging from the skeleton 600
above the cells and which distribute therein the pulp to be fil-
tered and the wash solutions;
e) a central distributor 100 essentially comprised on the one
hand, of a rotating circular distributing head 111 which has
cavities 118 lying in a circle, which are connected respectively
to the cells 200 through flexible hoses 216 and which rotates
together with the frame 300 and the cells 200 and on the other
hand, of a fixed circular collecting base 110 which has chambers
114 and compartments 112-113 bounded by radial partitions 120, the
rotating head 111 sliding when rotating on the fixed base 110 by
means of a sealing planar friction gasket 117.
Distributing troughs 810-B20 mating with the par-
titions 120 bound succeeding sectors for filtering and washing,
those liquids and gases which have gone through the cell filte-
ring beds in each sector being collected separately, each one in
one compartment among the compartments 112~113 to be t~n dis-
charged through corresponding pipes 108 ~wards separators 60 from
which the liquids are discharged through barometric pipes 59 into
collecting ~umps 70 or as shown in dotted lines in figure 1,
through pipes 59 towards suction pumps 80, the gases being sucked
from said separators upwards to a vacuum circuit 90 through a
- 10- 10'~9~6
collector 88-89.
~ e separators 60 are preferably arranged directly
below the filter center portion, underneath the distributor, in
such a way that the discharge pipee 108 from distributor 100 to
separators 60 be as short as possible and slant as strongly as
possible. The barometric discharge height which determines the
gravity flow of tho-se filtrates separated from the gas thereof,
towards the collecting pumps 70, is to be measured from the base
level of the separators 60, this requirement thus determining the
level the filter is located at.
In the known cell filters, the liquids and gases
sucked through the cell filtering beds and the gases formed inside
the filters remain mixed and are turbulently stirred in the gene-
rally unsuitable flow circuits down to the separators 60 which
caUsec heavy head losses, allowing but low flow rates and causing
generally a strong cooling as well as very disturbing cristali-
zings and scales which might even make some filterings impossible.
~ reover the known filtering beds have too high a
resistance to the passage of filtrates and gases, thus allowing
but relatively low filtering capacities per filtering unit area,
and they are also unsuited for intensive washing.
The devices for fastening filtering cloths and
beds are generally unpractical and have a problematical tightness
while encroachlng on the circumference of the useful filtering
surface.
Another filter disclosed in U.S. Patent 3,072,136
differs from the filter shown in figures 1 to 3 essentially by
the distributor construction and arrangement.
Indeed said distributor has in each compartment of
the collecting part, two subdivisions the bottom of which is
10~9C~B
connected to a discharge duct.
A partition with a low height between both said
subdivisions lets the gases as well as the liquid overflow pass
from the first subdivision to the second one. The discharge duct
from the first subdivision discharges tnerefrom but liquid while
the duct from the second subdivision should discharge all of the
remaining fluids, that is all the gases as well as a liquid.frac-
tion that comprises :
a~ the liquid discharged from the cells through the cavities lying
plumb with sa~ second subdivision,
b) the excess liquid which has overflown from the first subdi-
vision, and
c) the splashes and droplets carried by the gases originating
from said first subdivision. - .
~ The stirring of the gases with the liquids thus
goes on in the second subdivision and in t~.e wh~e discharge cir-
cuit thereof, only that liquid amount ~ ing part in said s~rring
being reduced and scale forlnation still occuring therein.
In the filter distributor according to the inven-
tion, particularly in the embodiments described hereafter and
shown in the accompanying figures, all of the liquid is immedia-
tely and completely separated from the undissolved gases in the
very body of the distributor, thus preventing the stirring causing
the scale formations in the mixed fluid circuits.
Moreover the improved filter .according to the
invention allows increased flow rates, short cycles and high ro-
tating speeds which strongly reduce or prevent inner scale for-
- . mation. It is moreover provided with increased-efficiency fil-
tering beds which are easier to use and allow to apply under bette
conditions, intensive outer and inner washings as disclosed notabl~
' - - 12 - 10~3~958
in French Patent 7,220,473 and U.K. Patent 1,376,383.
Figures 4 and 5 show a first embodiment of a
central collecting distributor 100 which has been improved acc-
ording to the teachings of the invention. Said distributor
comprisesthe same main components as the above-described conven-
tional distributor : distributing head 111 having as many ca--
vities 118 as there are filtering cells, said cavities recei-
ving through the ends 118A thereof each connected to a cell
through a flexible hose 126 (see figures 1 to 3), the fluids
sucked therefrom and discharging said fluids in sequence through
the ends 118B thereofinto the compartments 112-113 and chambers
114 in the collecting base 110, through the friction gasket 117.
The compartments 112-113 and chambers 114 form together a cir-
cumferential circle-shaped trough opening upwards, the position
of the partitions 120 that bound the compartments and chambers
re~tive to one another, being adjustable inside said trough.
Due-to their being open at the top, the compart-
ments and chambers communicate each with one or a plurality of
cells through the ends 118B of the corresponding cavities.
The application of a driving suction inside said
compartments causes a suction inside the cells through the cavi-
ties 118 and pipes 216.
Conversely a pressure inside a chamber is commu-
nicated along the same path inside the corresponding cells.
The cavities 118 move above the chambers 114 and
compartments 112-113 and communicate each in sequence with each
chamber and compartment. All of said compartments have prefe-
~ rably at the bottom thereof, at least one discharge outlet 109
facing downwards and connected to a discharge duct 59 (figure 1),
which is preferably a barometric duct and discharges the liquid
~ - 13 - 10~3~9~8
into a collecting sump 70 at the atmospheric pressure, from
which sump the liquid overflows or is sucked by a pump 80
(figure 1), for ex~mple towards a filtrate storage tank iO.
As a variation, a pump 80 can suck the liquid
under a pressure lower than the atmospheric pressure. In each
case, the exhaust circuit is so adjusted as to suck but liquid
free from any gas phase.
The discharge outlets 109' of the chambers 114
are connected through pipes 108' to discrete sources Of fluid
suction or pressure according to the operations which are to be
performed in the cells or in the distributor.
The chambers 114 are completely enclosed sidewise
by the inner c~cle-shaped walls 133A and th~ outer circle-shaped
walls 133B of said trough, as well as by the radial partitions
120. ~They communicate each downwards with a pipe 108' and up-
wards with the cavities that pass respectiveiy in front thereof.
;~ The compartments are bounded in the same way and
communicate with the discharge pipes and with the cavities.
However the inner circle -shaped wall 133A does extend but over
; a low height above the maximum level reached by that liquid which
flows over the bottom and thus said wall leaves free thereabove
for the gas release, large passageways 131 leading to the inner
volume of the distributor.
Vertical radial plates 132 bear the inner edge of
the sliding surface 117, with but a negligible encroachment on
the release passageways 131 for the gases; said passageways may
on the other hand be enlarged according to the gas flow rate
while the height of said trough can be varied at will.
As soon as it enters a compartment, the gas-liquid
mixture from any cell falls by inertia and gravity to the compart-
~ - 14 - ~0949~B
me~t bottom and then enters through the discharge outlet 10~,
while the gases which are subjected from the outset to the under-
pressure caused by a suction device, are exhausted sidewise
through the passageways 131 towards the free space left in the
center portion of the fixed distributor base and which extends
upwards into the free circle-shaped space in the rotating head
111, all said various spaces comprlsing a separating chamber 115
for the liquid droplets carried by the gases. The slanting bot-
tom 134 of said chamber returns to the original compartment bot~
tom those droplets whlch settle thereon.
The gases essentially free from the carried drop-
lets, are suckèd through the outlet 141 in the top portion of
chamber 115.
When required, the separating chamber can be
.
divided by partitions 138 into sectors communicating respectively
with one or a series of succeeding compartments.
The separating chamber 115 may be of truncated
shape as shown in figure 4, of cylindrical shape or of bUlbshape
and it may comprise when required, special shapes for the par-
titions 138, baffles or any other means required for the desired
settling of the droplets.
An additional final separator, not shown, can
when required, complete the capturing of the nest droplets, a
single separator for each suction source being required as oppo-
sed to the multiple separators 60 used as shown in figure 1 with
a conventional distributor.
- It should be noted that the fine liquid particles
~which reach the chamber 115 and/or the final separator, cor-
respond but to a negligible proportion of the liquids entering
the distributor and the cristalizings or scale formations they
- 15 - 109~958
may cause are thus minimized, without any common measure with
the ones that might result from the complete liquid amount.
The separating chamber 115 may be divided into
two or more enclosures isolated from one another and communica-
ting each with a discrete gas suction source.
In the example as shown in figures 4 and 5, two
enclosures 115' and 115" separated by a partition 139 communicate
through outlet opènings 141, 141' and pipes 116, 116' with
discrete suction sources.
The partition 139 is sealingly joined to the par-
tition 120 corresponding thereto.
The combination of a plurality of suction sources
with such discrete e~closures allows to apply different suction
magnitudes to the various filtering cell groups corresponding to
the various enclosures, said enclosures being graded according
to the best suitability for each one of the filtering phases and
washing steps, and such combination allows particularly to per-
form a thorough final draining of the filter cake before dis-
charging same, under a suction which does not affect the suction
or suctions applied to the filtering and washing sectors.
The fixed base llO is borne in ~e present example
by a standard 99. The rotating head 111 forms where it contacts
the fixed base, a joint 117 which is sealed under the action of
gravity and inner underpressure and said head is centered during
the rotation thereof for example by concentric centering collars
142 and 143 integral whith the fixed base and tne rotating head
respectively. Advantageously said joint 117 is comprised of the
engagement of a collar from sof~t resin 124 forming the sliding
surface of the rotating head, with a metal collar which forms
the top sliding surface of the fixed base. The steady wear of the
~ "
10!3~9c~8
soft resin on the hard metal retains a good sealing.
Instead of using as shown in figure 4, pipes 116-116'
connected to outlets 141-141' in the separating chamber top, the
gas suction may be made through pipes passing through the center
portion of the fixed base and the mouth of which lies inside the
separating chamber adjacent the top thereof, as it is the case in
the embodiment as shown in figure 6.
The carrying of droplets in the gases requires with the
usual industrial filterings, maximum rates thereof of about 3.5
m/sec. and preferably 3m/sec for a liquid viscosity of about 2
centipoise which corresponds to a minimum passage area Sp of .6
dm2 and ~referably .75 d~2 per square meter of active filtering
surface, said values may vary according to the viscosity. The
passage area for the rising stream at the separating chamber bottom
Se, as shown by arrow 136, should be at least .8 dm and preferably
1.25 ~m2 with outlet openings 141-141' of .15 dm2 and preferably
.25 dm2, all these values being given for one square meter of
filtering surface. The travel length left for the gases in the
separating chamber should be such that the vertical distance from
Se to Ss be at least 0.5 x Sse.
For filtering with very high or very low gas flow rates,
the above usual values for the passage areas would be increased
or reduced according to such flow rates.
The partitions 120 and 139 can be adjusted in position
according to the division of the various sectors which the operator
wishes to assign to the filtering of succeeeding liquids. Figures
18 to 21 show by way of example, two embodiments of adjustable
partitions.
In figures 18 and 19, each partition comprises two half
3~ partitions 120A and 120B assembled by means of a bolt 120C with
~- slanting surfaces, which ~hen the bolt is tightened, press both
half partitions against the trough walls 133A and 133B.
- 16 -
- 17 - ~0~3~958
In the embod:iment shown in figures 20 and 21,
recesses 120F let the partitions slide over rails 120D, the par-
titions being wedged on said rails by means of clamping screws
120E. The partitions 139 may for instance swing about a central
vertical shaft 137 and be locked by any usual means, such as bolts
or pins.
The final cake drying at the cycle end, before
discharging said cake, may be performed under the action of one
chamber 114 w~ich is connected to a discrete suction device which
sucks a large air volume through a particular droplet separator,
thus retaining the separating chamber for the relatively low gas
flow rates of the filtering operations proper.
The direct suction through said particular sepa-
rator~of the air`pass~g through the cake already relieved of the
liquid thereof does no more result in a danger of scale formation
which the invention seeks to avoid.
Some other changes in the new distributor according
to the invention will be described hereinafter as regaFds the main
features which differ from the first embodiment shown in figures
4 and 5.
In a second embodiment shown diagrammatically in
figures 6 and 7, the rotating unit 111, 118, 124 is integral with
the top portion of the separating chamber 115 whicia rotates there-
with, while the chamber bottom portion comprises the center pa~t
of fixed base L10, the gas suction being performed through the
pipe 116 which goes ffrough the fixed base and the mouth of which
lies adjacent the separating chamber top.
In a third embodiment shown diagrammatically in
'
figures 8, 9, 10 and 11, the movable part 111 with the cavities
118, rotates between two friction gaskets 117 and 117', between
10949~8
the fixed separating chamber 115 and the fixed base 110 whith
t~ compartments and chambers. The cavities have two outlets, ?
an upward outlet 118A for the gases to the separating chamber,
ard a downward outlet 118B for the liquids to the compartments
and chambers in the fixed base
The liquid-gas separation is thus made originally
and essentially in the cavities, to be then completed in the
separating chamber. The sliding surface thereof is open above
the compartments but closed-off above the chambers 114 and 114'.
The rotating part has a core 125 to which are
connected spokes 126 and which rotates about a center pivot 127
of the fixed base 110~
In a fourth embodiment s~own diagrammatically in
figures 12 and 13, the sliding gasket 117 is of frusto-conical
shape and the rotating head 111 rotates together with the cavities
118 thereof,-about a conical surface of the fixed base 110 which
is provided with ~enings communicating with the chambers 114 and
114' and the compartments 112-113, inside wkich the flui~s enter
sidewise, the gases are released at the top, and the liquids flow -
-
through the bottom outlets 109 and 109'.
The fixed separating chamber 115 tops the fixed
base 110 and is integral therewith. The rotating head 111 rotates
on a rolling race 121.
In a fifth embodiment shown diagrammatically in
figures 14 and 15, the rotating head 111 rotates about the unit
formed by the fixed base 110 and thç separating chamber llS, by
sliding on a vertical cylindrical sliding surface 117 and rolling
on rollers 121 while being guided by centering roIlers 122.
In a sixth emhodiment shown diagrammatically in
figures 16 and 17, the separating chamber llS and the rotating
- 19 - ~O~
head 111 for~ a single unit which rotates by sliding on a hori-
zontal ring-shaped gasket 117 which engages the fixed base 110.
To the difference with the preceding embodiments, the sliding
gasXet does not have any opening for the passage of the fluids
from the movable part to the fixed part. The cavities 118 lie all
around the lower portion of the rotating unit, the gases are
released upwards in the separating chamber and the liquids flow
down into the base compartments, while the chambers 114 and 114'
form bent ducts passing through the fixed base and communicating
with the openings 118 through gaskets 129 engaging the cylindrical
sliding surface. By way of example, said gaskets are made from
resin and applied against the cavities by means of pressurized-
air pockets 130 as shown in figure 11, or by similar means such
as springs - not shown.
The essential advantages of the new distributor
type according to the invention, which might be called "distri-
butor-separator", are as follows relative to the conventional
distributors :
1) it does away substantially, or at least strongly reduces in
the most heavy cases, with the scales both in the distributor
itself and in the piping and appar~tus that lie downstream in the
filtrate circuits;
2) it allows to do away in the filtering installation, with the
multiple inner separators together with the complex piping network
thereof for connecting to the distributor and the vacuum circuit;
3) it allows to lower the filter level by 3 to 4 meters relative
to the conventional case where external separators are mounted
underneath the filter center;
4) it allows to strongly reduce or even do away with foaming
caused by turbulent gas-liquid mixtures, due to the previous
- 20 - 10949u~8
separation of the gases and the better fluid flows;
S) it allows to substantially reduce and smooth the head losses
in the filtrate and vacuum circuits, which results in a better
vacuum utilization.
The new distributor-separator type according to
the invention may be applied to any cell filter, whe~her the
cells thereof are fixed or movable with a rotating or transla-
tion movement.
Another improvement according to the invention
which can be applied to cell-filters in combination or not with
the above-described distributor-separator, relates to means
insuring a fast flow and discharge of the filtrates and gases
removed from the cells.
The improved cell 200 of trapezoidal shape has
been shown diagrammatically in figures 22, 23, 24. It does com-
prise a bottom 201 with at least two ~lanting surfaces, prefe-
rably by 4 to 8 to the horizontal, towards a draining channel
203 which extends along the cell lengthwise axis. The channel ;~
bottom slants by 1 to 4 towards an opening 204 connected to a
pipe 216 for letting out and discharging the gases and li~uids
to the distributor. Said channel is provided with guiding,
dividing and distributing means for the fluids which are àdvan-
tageously comprised of baffle-plates 205 located at the channel
top and slanting towards the mouth 204, thus providing an aper-
. . .
tured inlet bo ff~channel over the whole length thereof and guiding
the fluids to the mouth.
According to the invention, the total cross-sec-
tion area of the passage through the plate network is equal to
1.5 to 6 times, preferably 1.5 to 3 times the smallest cross-
,:
section area of mouth 204 which is proportional to the filtering
- 21 ~ 10~3~9.58
surface area of the cell and to the fluid flow rates typical of
the considered filtering, that is .2 to .6 dm2/m2 filtering area,
for the most usual filterings.
The plate advantages are more marked for the usual
filterings when said baffle-plates have an angle of 2 to 20, pre-
ferably 3 to 12, relative to the horizontal plane, the end plate
opposite the mouth might have an angle of 20 and even up to 30.
The slanting angles are larger for the larger fluid
flow rates.
As a variation for the baffle-plates, the dividing
and distributing of the fluids might be obtained but with general-
ly less advantageous results, by means of a channel top wall pro-
vided with a series of callbrated openings distributed over the
lenght thereof and having an increasing cross-section area from
opening 204. Such a variation has not been shown however.
Advantageously, the dlviding made at the inlet to
channel 203 is extended -in all of the space hetween the cell bottom
, . .
and the filtering bed by means of ribs 206 substantially at right
angle to the channel, which divide said space into flow compartments,
said ribs also being used to support the filtering bed.
- Each baffle-plate 205 connects with the top edge
thereof to one of the ribs 206, the unit formed by the plates and
the ribs comprising for the fluid flow, a series of parallel chan-
nels inside which is generated one and the same driving suction
which extends down to ~nderneath the filtering cloth. The plate
number lies advantageously between 1.5 and 10, preferably 2 to 4
per running meter of channel length, while the rib number may be
to 10 per running meter. The ribs provided between two ribs
which are connected to baffle-plates may be apertured.
~ - 22 - 10~9~58
Figures 22, 23, 24 show a swinging cell provided
with a shaft 220 and bearings 230, but the invention also applies
to non-swinging filtering cells.
The invention further relates to improvements to
the fastening of the filtering cloth and the support thereof,
particularly in filters with swinging cells, such as the Prayon
filter.
FLgures 26 and 27 show a first embodiment of such
fastening means in which the edge 207A of the cloth 207 is folded-
back against the side wall 200A, the unit comprised of cloth 207
and support 208 is pressed at the cell bottom against the ribs
206 and circumferential shoulders 200B by a set of rods 242 having
two diverging lengthwise arms the free lengthwise edges of which
.
~ are provided with projections 242A and 242B. Said rods 242 are
.,
combined with a set of U-sections 241 with a high stiffness which
are applied horizonta~ly against the outer surface of wall 200A.
The rods 242 are located on the inner surface of wall 200A so as
to mate with the cloth edge and the outer sections 241. The
edge 207A is clamped between rod 242 on the one hand, and the
wall 220A and the section 241 on the other hand, by means of two
gaskets 245A and 245B from rubber or similar material~ sealing
being easily obtained with the linear engagement of the length-
wise projections 242A and 242B of rods 242 that press the gaskets
and cloths against the stiff sections 241.
The pressing together of this whole unit is ob-
tained for instance with bolts 243 spaced by 20 to 40 cm, which
are introduced by way of the inner surface of the cell edge and
scre~edthrough the rods, the gaskets 245A and 245b of wall 200A
and a section 241, into a nut secured to said section.
- 23 _ 1 0 ~ 4 ~5 8
Such an arrangement allows an easy and fast
replacement of the clo~h requiring but the handling of a small
number of bolt shafts 243.
The fre~ lengthwise edges of rods 242 are provided
with a slanting surface, the free lower edge bearing on the cloth
207 and the support 208 to apply same unmovingly against shoulder
200B that extends over the circumference of inner wall 200A~ under
neath the support and agalnst ribs 206 which extend cross-wise
to the bottom of cells 200.
. As the above-described securing means project but
slightly inside the cell, they encroach very little on the fil-
tering surface, they let the suction generated inside the cell
draw more smoothly and efficiently the fluids along the cell
circumference, they improve thereby the washing efficiency of
the cake margin, they lower the final moisture contents thereof
and they enhance a straight fall of the cake over all of the
circumference thereof when the cell turns-over.
It should be understood that the invention is in
no way limited to the above embodiments and that many changes
may be brought therein without departing from the scope of the
inventiOn as defined by the appended claims.
.
