Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
CA 02243~74 1998-07-24
Water operated apparatus for the collection a~d sedimentation of
paint particles
The present invention relates to a water-operclted apparatus for
the collection and sedimentation of paint particles in a mixture
of water and pairt particles that are either suspended or
floating and which are adhering to each ctherf with a flow
channel and quiescent ~ones, and wlth a retu~ll flow pipe that is
connected to the flow channel.
Water-operated apparatus that are arranged beneath one wall of a
spray-painting cabln or a spray-painting stand, that is
l~ constantly flushed w~th water, and which Wâsh out paint mist
during the paint.ng process, are already know~ (EP 0 529 151 B1).
These known apparatus incorporate a ransverse channel at the
out-flow end and this is adjacent to a f_ow edge of a water-
collection basin that is flushed in the transverse direction. The
2() transverse channel is formed with an essentidlly hori20ntal flow
seclion, at least ln the water-entry s~de cf the transversely
flushed area of the rlow edge, and the outflcw slope is adjacent
to this. The paint particles adhere to each c:ther, with the
result that they stick to each other and fl.o~t on the surface of
CA 02243574 1998-07-24
the wate~ ln patches, are not wetted, and for t~Lis reason do not
form a sediment.
Desplte the addit_on of -, surfactant to the vv~ter, this
S phenomenon remairls because this known wate--~erated apparatus
does not wet the paint particles sufficientl~l and totally. The
dry surface of the paint, which extends abov~- the waLer, remains
tacky and allows additional paint particles to stick to it, so
that these agglomerate tG form a thic~ and continuous layer of
paint. At a certain size, the weight of this accumulation of
paint sludge is greater han its buoyancy an~ it sinks to the
bottom, after whL n it can only be removed manually.
Accordingly, the task is to ensure that unwetted and extremely
1~ adhesive floating paint sludge that is no we ted is no longer
formed in a wate~-operated apparatus.
This problem has beer. so'ved by a water-oper~-ted apparatus of tht
type described in the introduction hereto, this beirg
characterised in that the apparatus is provlded with at least one
weir that interrupts the flow through the fl~)w channel and over
which the water passes.
CA 02243~74 1998-07-24
Th-s weir, which lS not simply an edge over w~1ich the water
flows, generates an undertow that picks up the paint particles,
submerses them, breaks them up, and wets the~.
In addition, a coagulant can be added to the ~ater; as is known,
th_s reduces the tackiness of the paint partl~les although
despite this, because of weak adhesive forces, this simplifies
coagulation and c-lumping of the paint particles that have
se~tled.
n
It is an advanta~le if not only one we r, but rather a plurality
of weirs, be arranged in series, one after the other, in the
manner of a cascade. When this is done, it is preferred that the
overflow level from one weir to the othe- differs by 0.05 to 0.2
1~ me ~es. It is important that a reversing un(iertow be formed
after one such weir or after each weir, with.n which floating
paint particles can be drawn into and beiow the water so that
they are wetted and no longer float.
In the normal cc~lrse of events, three to six such weirs are
su~~icient to wet all the floating and c~alesced pairt particles
an~ cause them t~ sink.
In order to reduce the space that is require~-, it is proposed
that the flow channel be configured so as to follow a meandering
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path, with the wel'-S being located preferabl~ in the areas where
this meander path changes direction. The change in direction of
the flow channel at these meander polnts should be 180~ at each
such point.
A quiescent zone is formed in front of each weir and some of the
paint particles will form a sediment in this ~one. The sludge
that has formed c)n the bottom can be removed from these areas by
means of suitable slides or tub-type conveyors. For this reason,
the standard ver~sion is characterised by weirs that consist of a
rebound wall tha+~ extends down to the bottom of the flow channel.
Removal of the sludge is rendered simpler in one version in which
at least some of the weirs are formed by a combination of impact
walls that consists, in each instance, o- a first impact wall
that extends dowrl ~o the bot+om of the flow (-har.nel and a
subsequent impact wall, the lower edge of wh:ich does not extend
to the bottom of +he channel so that there is a gap between its
lower edge and the bottom of the channel. ~hls creates a flow in
which some of the sludge that sinks +-c, the bcttom oollects in
front of the impa-+ wall that extends as far ac the boltom of the
channel. The sludge can then be removec from this posi~ion. If
the first impact wall is arranged so that it can be raised and
lowered, when the impact wall is raised, the sludge can be
2~ flushed into the end area of the flow channe:, from where it car
CA 02243~74 1998-07-24
be removed after it has been allowed to se tle. To this end,
suitable pumps can also be installed to draw the deposited sludge
downward.
In order to provlde for further deflect:~on cf the flow, the
bottom of the flow channel can incorporate bGttom un~ulations or
bottom steps so that the resulting undertow -s lntensified. Such
bottom undulations should in each instance be arranged such that
their crests lie n front of a weir.
Since, according ~o the present invention, t~l~ paint-particle
mixture still con~ains gas, it is proposed th~t a venturi
scrubber be arranged at the beginning of the flow channels, in
the vicinity of c)r above the first weir, in order to remove fine
dust from the unt~eated gas.
Embodiments of the present lnventiGn wil~ be ~escribed in greater
detail below on the basis of the drawingc appended hereto. These
draw ngs show the following:
Figure 1: a diagrammatlc view of a water-oper~ted apparatus that
is adjacent o a spray-pair.tinc ca~.n wall tha is
sprayed with water.
Figure 2: a diagr-arnmat c view of an apparatuC wlth a flow channe'
in the form of a meandering path;
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Figure 3: an embodlment of a flow chcnne Wlt-n bottom
undulatlons;
Figure ~: an embodiment of a flow channel with bottom steps.
Figure 1 shows a wall 2 of a spray-palnting cabin that is sprayed
with water, on wh ch paint particles that or-~ nate from a paint
mist are deposited and routed downwards throu~h a mesh base 3
together with the water from the spray. The water 200 with the
paint particles collects in a drain trough ~ and flows over an
inclined overflow edge 8, strikes a drain slope 9, and then flows
into the flow channel 100. There ls an opening between the
overflow edge 8 and the drain slope 9. F_ne, dust-like particles
of paint that are present in the drain water can be drawn of
through this venturi scrubber ll and suitabl~ separated. A drain
channel 11' is provided for this purpose.
Figure 1 shows a low channel 100 that comprlseC a plurality of
sections that are arranged linearly one behind the other, each Gf
which is defined by a weir 10.1, 10.2, 10.3, and 10.4. The water
flows over these weirs. In the embodimeIlt that is shown in
Figure 1, the we r comprises a lower lmpact ~all 5.1, 5.2 that
stands on the bottom of the flow channel 100, and a subsequent
impact wall 6.2, 6.2, the lower ed~e of whlc~ does not extend as
far down as the bottom cf the flow channel 1(0 so that there is
gap between the lower ecge and the bottom of the flow channel.
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The impact wall ~,.1, 6.2 is manufactured froI[l two separate metal
sheets that are joined together in order to m~}e it simpler to
vary the height of the wall.
The water passes from the drain slope 9 t~ a quiescent zone 1 in
front of the first impact wall 5. The water then flows on and
becomes an undertow 16 that pulls the floatin~ paint-particle
patches beneath the water and compresses them so that they break
up and become wetted. The paint particles thâ~ are now sinking in
the quiescent zone 1' build up in front of the lmpact wall 5.2.
Additional water passes over the next impact wall of the weir
10.2, the overflow level differing by approx.~ately 0.05 to 0.2
metres. This cascade arrangement of the we rs with an overflow
level that grows e~er lower results in the paint patrhes that are
l~ adhering together becoming wetted and submerg~d, and these then
break up and form a sediment, so that on'y a few paint particles
are still settling to ~he bottom or floa~ing ~n the surface at
the end of the cascade arrangement, lr the area of t:he quiescent
zoIle 21.
The water, from which most O r the pairt particles have been
removed by this point, then passes through ar. inlet 15 of a pum~
12 that is connected to a return line 13, an(~ is returned to th~
water in the flow channel at the point numbe-e~ 200. Only the
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small quantity of water that is lost as a result of residual
moisture and evaporation must be made up on ~ continuing basis.
Environmental-pro~ection legislation require that the wall of the
spray-painting cabin that is sprayed with water and the component
parts of the flow channel be located within a protective catch
basin 14.
Figure 2 shows a plan view of a water-operate~ apparatus as is
shown in Figure 1 and which is based on the same principles. The
flow channel 100 ~s in the form of a meander ng path. Weirs,
similar to those shown in Figure 1, are preferably located in the
areas where the meandering path changes direction at 24.1 and
24.2. As in Figure 1, the weirs 10.1 and 10~2, and any others,
1~ consist of a lower impact wall 5.1 anc a subsequent impact wall
6.-, so that the parti les that sink to the ~ttom will
accumulates here, ~oo.
In he embodiments tha are shown n Figu~e and Figure 2, the
helght of the front (lower) impact wa~l 5. , 5. 2 can be
adjusted. For th s ~eason, when the low of ~ater is cut off, a
flushing flow can be generated such that once the impact walls
5.1, 5.2 have been raised, the paint sludge that has collected in
front of these impact walls can be flushed irito the area of the
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qulescent zone 2L! where it collects and fro~. where it can be
removed by a sump pump or by a chain conveyor (not shown herein).
It should be notedr in particular, that operation in the sense of
the present inventlon is also possible if. the weirs consist only
of impact walls that rest on the bottom or which are so arranged
that there is a space between their lower edges and the bottom.
Figure 3 shows ar embo~lmer.t ln whlch the bot:tom of the flow
channel, which can be rectil_near, curvecl, or ln the form of a
meandering path, can also be provided with ~ctt3m undulations 18
that are so arranged that there is a quiescent zone in front of
l~ the impact walls, whereas the flow path s re,tricted after the
impact walls, since thls permits ~mprcvecl entrainment and wetting
of the paint part::~cles.
The crest 17 of the bottom undulations referred to above should
in each instance be -n f:ront of the weirs.
Figure ~ shows c further embo~imerlt. ln th~s, tLle cascade-like
arrangement of the weirs is such that the mp~ct wal:Ls that are
set at a specific distance from the bottcm are each arranged at
2~ the end of a bottom step 19 that ends in a fa11 area 19'.
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The height of the impact walls 10. 1,..., 10.3 can be adjustable
or they can be set on the bottom in t~Le form ~f dams so that an
undertow 16 is formed above them.
The sludge that forms in the sump 22 can be crawn off with a sump
pump 23 and a draln pipe 25, and then be passed on for disposal
or for recycling.
The manner in wh ch the apparatus acccrdlng t~ the p:resent
lo invention ope~ates w~ now be described b~lefly once again:
The water passing ~rom t:he drain trough ~ mixes with the un-
processed gas and _s intensively swir_ed n ~e fo:llowin~ venturi
scrubber; it then passes to the first we.r 1(~.1, after which it
1~ moves into the qulescent zone 1, where the f rst sed.imentation of
the sludge takes p_ace. The floating paint-particle patches 26
are drawn into the undertow 16, submerged, arld broken up by the
turbulence and the buoyancy forces that are a-tlng there. They
are easily wetted and coagulate and fcrm a slldge sediment in the
2n cuiescent zone 1'. The subsequent cascade-li~:e weirs provide
additional undert:ows and thus ensure that:. th~ remaining paint-
particle patches are wet-ted.
The paint sludge hat co.llects is remcvec elt.~er by a tub-type
2~ conveyor or by a suitable sump-pump system. 1'~ one particular
CA 02243574 1998-07-24
embodiment, it is also possible to flush the paint particles intc
a special, rear, quiescent a~ea that is provided wit:h a sump pump
(see Figure 4).
Water losses and water contamination are kept at low levels by
recirculating the water.
CA 02243574 1998-07-24
Reference numbers
100 --low channel.
200 water
2 water-sprayed wal:l of spray-palntlng cabin
3 mesh bottom
4 drain trough
5 first, lower impa(-t wall
5', 5" quiescent zone
6 second impact wal:l
7 inlet pipe
R overflow edge
9 drain slope
10.1...10.4 weir
-1 venturi scrubber
'1' drain chdnnel
_2 pump
_3 return line
:4 protective catch basln
:5 inlet
:6 undertow
~7 crest of bottom undulatlon
:8 bottom undulatio
'9 bottom s~ep
~9' fall area
20 gas remova'
21 quiescen~ zone
23 sludge-removal pump
24.1...24.9 meande- curves
25 drain pipe
3() ~6 pa~nt-part-cle patch
