Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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HOE '77/H 017K
This invention relates to a degassing column for re~
moving monomers present in a polymer dispersion compris- :
ing a tubular shell provlded with a plurality of apertllred
plates, said plates being vertically spaced wlthin said
shell, a small gap uni~orm in width over the periphery
being left between each of said plates ~nd sald shell~
each of said pla-tes being penetrated by at le~t one
eccentrically arranged condui-t comprising a draining
shaft in the upper portion thereof and a feed sha~t in
the lower portion below the penetrated plate, the aper-
tures in said plates having a diameter of less th~n 5 mm,
and a surface portion of each plate underneath each oon-
duit being impermeable, said impermeable sur~ace portionbeing one to two times the cross-section of said conduit.
In view of the great variety o~ liquid materlals,
including in partlcular polymer di~persions, which may ~:
have to be freed from gas or vapour; e. g. vapours of
monomers, ln a d~gassing column, and in view of the de-
sirabllity o~ an improved degasifying effect~ it would
be highly des~rable to have a de~a~sing column wherein
the distance between the upper end o~ each draining
shaft and the respective plate, i. e. the weir height,
could be varied.
It is therefore and object of the present inven-tion
to provide a degassing column of the type described in
which column the weir height of the plates can be modi~ied
ln a simple and inexpensive manner according to the par-
ticular polymer dispersion which is to be treated ~nd the
degree of degasi~ication which is aimed at. .
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According -to the presen~t inventlon3 we pro~ide
a de~assi.ng column compri~ing a tubular ~hell provided
wit,h a pl.ural.i-ty of ~pertured pl.ates; said pla-te~ being
vertically ~paced withln said shell; a small gap uniform
in Wi~t}l o~er the pe.riphery being left b~tween each of
said plates and said shell; each of ~ald pla-tes being
pe~etrated by at least one eccèntrically arran~ed con-
dult comprising a drainislg shaft in ~the upper pf~rtion
thereof and a feed shaft in the lower por-tion below ~he
penetrated plate; the apertllres ln said pl~tes having a
diameter of less than 5 mm; and a surface portion of each
plate undernea-th each conduit ~Lng impermeable, s~id im
permeable surface portion being one to two times the cross-
seotion of said conduit; ln which degass:Lng col.u~n a capp~
ing sleeve is slipped over each drainin~ sha~-t, -the capping
sleeves each compri~ing an upper portion whose cro~s-
section is similar to that of -the draining shaft, and a
lower por-tlon of larger cross section~ which lowe~ portion
overlaps and is securely connected to the upper p~r-tion.
.0 Pre~erred features of the present invention provide-
a) for each of the capping sleeves to be ~ormed in its
lower por-tion with a plurality of slits distributed
around its periphery, in which slits there are engaged
respectlve bolts secured in a radial orientation to
the draining shaft;
b) for the slits each to compr.ise a lower portion wh~ch
extends in the axial direction of the capping sleeve
and an upper portio~ which extends tran~ver~ely with
re~pect thereto;
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c) for the capping sleeves each to have three of
the ~a:i.d sllts;
d) for the said bolts to be screw-th.readed, arld
e) for -the capping sleeves to he held in position
by means of` nuts screw-threadedly engaged on the
said bolts.
In a degassing column according to -the present ln--
vent.lon) i-t ls possible to provide the plates with per~
~orations spaced apart at interval.s of 15 mm, for example,
: 10 so that ~olid matter is not llable to deposit evell if the
wid-th over which the rings are supporting the plates is
up to 20 mm. Solid matter is al~o not liable to d0po~it
on the column wall inasmuch as we do no-t contemplate that
the lat-ter should be very effectively heat-insulated, so
that a condensate~ e. g~ wate~ if steam is pr~sent within
, the colum~l, can contimlally form on the inside of the
; column shell and can run down ~n the ~orm of a liquid
film producing a washing e~fect.
The impermeable sur~ace on eac,h plate below the re-
spective shaft has an area which is pre.~erably 1 to 2
-times the cross-sectional area of the shaf-t.
In a typical construction in accordance with -the
i~lvention, the distance ~etween -the upper end of each
conduit and the respective plate is 80 to 400 rn.m, and
25 the lower end of each conduit terml.nates 10 to 100 mm
above the pla-te below it.
Cer-tain embodlmen*s of the present invention are
shown dlagrammatîcally in the accompanylng~ drawings,
in w~ich:
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Figure 1a is a sectional side elevation view of
the degassing column;
Figure 2a is a sectional side elevational ~lew
of a draining shaft ha~ing a ~ap rnountlng
slipped over it;
Figure 3a is a side view of a drainillg sha~t having
a cap mounting slipped over it; and
Figure 4a is a plan view of the draining sha~t of
Figure 3a.
As can be seen in Figure la, a series of perforated
plates 2a which are vertically space apar-t is arranged
in a column shell 1a, a gap 3a uniform in wid-th around
the periphery being left between each plate 2a and the
column shell 1a. The plates 2a are penetrated by a plu-
rality of stay bolts 4a, the portion of each stay bolt
4a extending between two ad~acent pla-tes 2a being con-
centrically surrounded by a slee~e 5a, which ~upports
an upper plate 2a, and which suppor-ts itself wi-th ~t~
lower end on a lower plate 2a. ~n eccentrically arranged
conduit serves to provide a feed sha~t 7a which ter~inates
above each plate 2a; also each plate 2a is penetrated by
an eccentrically arranged conduit which serves to pro-
vide a draining shaft 6a. Positioned below each feed
shaft 7a, on the respective plate 2a, is a covering
sheet 8. Slipped over each draining sha~t 6a i~ a capp-
ing sleeve 9a, which enables the we~ height, i, e. the
distance between the upper end o~ the drainin~ sha~t 6a
(extended by means o~ -the capping slee~e 9 ) and the
plate 2a, to be readily varied, in accordance with the
length of the capping slee~e 9a which i~ selected. The
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capping sleeve 9a comprises an upper portion lOa
(Figures 2a and 3a) of which the cross~sec-tion is similar
to tha-t of the dra:ining shaft 6a, and a lower portion l1a
o~ larger cross-section, which overlaps the upper portion
10a and i.s securely connected -there-t,o. The lower por-tion
11a of the capping sleeve 9a is formed wi-th a plurality
of slits 12a (Figure 3a) which are d.istributed around
it~ periphery at uniform angular intervals. The slits 12a
have a lower portion which extends in the axial direction
of the capping sleeve 9a and an upper portion which ex-
tends transversely with respectthereto, thus giving a
bayone~ connection of the capping sleeve 9a to the shaft 6a,
Dis-tributed uniformly around the periphery o~ the
draining shaft 6a and fastende radially there-to is a
plurality of threaded bolts 13a (Figure 4a). The capping
sleeve 9a is a-ttached by so presenting it to the shaft 6a
tha-t the bolts 13a enter the slits 12a provided in the
capping sleeve 9a t and then turning it abou-t the axis
of the shaft 6a until l-t cornes to a stop. The capping
sleeve 9a is held in position by tightening on to it
nuts 1L~a carried by the bolts 13a.
It is advan-tageous in -this embodiment o~ the in-
vention to use capping sleeves which permi-t the weir
height to be varied by 20 to 400 mm~
The presen-t degassing column is useful for a
varie-ty of applica-tions, e. g. the re~oval of monomers
from polymer dispersions,
