Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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This inven-tion relates to a process for the intermi-t-
tent aeration of liquids such as, Eor instance, waste water
or the like media in aeration -tanlcs by means of an aeration
device arranged below the surface of the liquid and compris-
ing at least onesupp~rit~r~bod~, an air--feeding line, and
a preferably elastic diaphragm covering the supporting ~b~
and being of air~tight material having as perforations punc-
tures, slots or holes in parts thereof, as well as a frame
structure locking the supporting ~b~ in position.
An air-distributing device for carrying out a process
of aeration by treatin~ water with fine air bubbles is known
from the German patent 29 ~2 607, the criterion of which
is the arrangement of an air-tight foil and a ~erforated
foil superimposed on the former, in a frame constituted by
two oppositely directed angle frarnes which have the function
of a tentering frame, with supporting stays extending under-
neath the unperforated foil being further connected to the
said frame. Above the perforated foil, there are provided
further, uniformly distributed stabilizing foils at a short
distance from the foil, which extend at 90 relative to -the
lower stays.
; A thus devised air distributor will indeed fulfill the
tasks confronting it in this instance in so far as a most
uniform distribution of air possible can be achieved over
the entire distributor surface. This device suffers, however,
from the drawback of requiring a relatively heavy, well
stiffenèd, weight-demanding double frame construction which
renders manipulation of the aerator in the aeration tank
difficult.
A further drawback of this construction is the position
of the plane in which the aeration surface lies under the
surface of the water, which position depends on the weight
and cannot be adjusted.
Furthermore, devices are known which have supporting
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bodies provided ~ithopenings for the passage of air and
covered by a perforated air-dlstributing foil or enveloped
by a perforated hose, and which as a rule require the ar-
rangement of additional tensioning means for locking the
hoses or foils, respectively, in posi-tion.
These known devices suffer generally from the drawback
that, in the case of possible damaging of the air distribu-
tor foil which can always occur for any number of reasons,
water may penetra~e into the supporting body and can lead
to a premature closing of the perforations, in particular
in a period of rest.
Moreover, it is not only the air~distributing foil or
perforated hose, respectively, which is endang~red by the
entering waste water but especially the supporting body it-
self as the cross sectional areas of the air discharge open-
- ings inthe supporting body are in such a case openly acces-
sible practically without restriction.
It is a further drawback that, in the case of tubular
aerators, only the upper reach can be considered as the
aerating region proper, and this region is, in many cases,
interrupted by auxiliary holding sleeves or the like.
As in the case of the initially named publication, an
attempt is often made to g~e~ the aerating foil a position
oE aeration as nearly horizontal as possible, with the aid
of stays keeping it down, in order to avoid excessive tens-
ioning of the upwardly vaulted region -thereof.
As a foil displacement undernea-th the stays cannot be exclud-
ed, excessive tensioning may nevertheless occur in the indi~
vidual supported areas.
The superpositioning of sheet metal sieves which has
also been tried, will reduce the uniformity of air distrib-
ution.
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'~aking;into account this sltuation, it is a task of the
instant invention to provide a process oE the initially des-
cribed kind which, in principle, facili-tates the manipula-t-
ion of aeration surface relative to the plane of the water
surface, by means of a speciflc, substantially lighter em-
bodiment thereof, thereby enabling a particularly effective
adjustment of the direction, distribution and concentration
of the feeding of air into the waste water, with the least
possible covering and obstruction of the air discharge caus-
ed by supporting built-in parts.
Moreover, there shall be provided a device suitable for
carrying out the novel process in practice.
This problem is solved, in accordance with the invent-
ion by providing, in the initially described process, a ri-
lS gid, self-supporting supporting body being porous or provid-
ed with perforations and covered by an elastic diaphragm,
on to which body the air is directed subs-tantlally vertical-
ly in at least one deflecting reach, and substantially in
its center of gravity or in series distributed along a gra-
; 20 vity line, and toward the wing pcriphery which is disposed
slightly higher vis-a-vis that center of gravity, with de-
creasing pressure into the water to be aerated, in an aerat-
ing plane ~Jhich is inclined with regard to the water surface
at an angle of up to + 90 and can be swivelled to adjust
that angle.
By the use of a self-supporting aeration plane which
is inclined at an angle of up to + 90 toward the periphery
relative to the center of gravity, and whose cross-section-
al area is of frustoconical, calotte, circle, wedge or pyra-
mid shape, and, lastly, forms an umbrella when rounded aera-
tion planes are used, there is made possible, by this shap-
ing alone, the formation of a specific light-weight support-
ing wing of high stability, while, simultaneously, the aera-
tion plane can be of articulated, i.e. slewable embodiment.
One should keep in mind that in the case of a normal arrange-
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1 32 1 428
ment, i.e. an arrangement of the plane of the periphery pa-
rallel with the water surface, the region of the aeration
tank to be aerated will suffer a bundling connected wi.th an
increase in the aeration concentration by a degree dependent
on the pressure, at a given displacement of its level vis-
a-vis the air supply, which displacement is directed toward
the water level, while it will become enlarged, connected
with a decrease of the aeration concentration, at a displace-
ment of the said level away from the water surface.
Of course, as a rule, a vaulting of the supporting face
toward the water surface in the shape of a wedge, cone or
pyramid will be preferred as this will afford the most uni-
form tensioning of the diaphragm, starting from the region
of air supply up to the periphery.
A reverse arrangement is likewise possible which, how-
everdemands.speci.al care in affixing the diaphragm in the
region of air supply, and the embodiment of the supporting
body face from the region of air supply up to the periphery
~ is suitably inwardly vaulted, i.e. of concave shape.
- 20 In the case of particularly deep tanks, it may even be
suitable to tend the membrane facing downwardly over a body
of calotte, circle or spherical shape, so that the air is
first discharged in the direction toward the tank bottom,
and then deflected upwardly via the peripheral region.
The dispersion and the velocity of a complete or part-
ial discharge of the supplied air can be improved still fur-
ther by causing the aeration face and thereby the wing face
to rotate about the center of gravity and to transfer the
air into a divergent vortex trail.
A device suitable for carrying out the above-described
process according to the invention comprises a rigid support-
ing body face constituting an aeration surface in connection
with a diaphragm and being of random shape, the static re-
sistance of which is determined, besides the choice of mate-
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rial and the dimensioning oE i-ts thickness, by the magnitude
o the displacement of its level to the edge-limiting peri
phery thereof, situated up -to ~ 90between the deepest point
or the deepest limit in the center of gravity or on the
gravity line, and that the inclination of the same determin-
ed by -the cross-sectional area of the suppor-ting body face,
leading from the deepest point or deepest limit to the edge-
limitin~ periphery, is formed to extend straight-lined,
shaped as a circle or calotte or, in the direction of a
raised level, with concave or convex shape.
Concerningthe selection of material to be decided upon
for making the aerator face, it should be noted that the
same can be made from hi~h-quality steel, porous or sintered
material synthetic resin material or the like substances.
As a rule, the diaphragm is made in a convent.ional man
ner, from an elastomer, in particular synthetlc caoutchouc
the elasticity behavior of which is adjustable in the widest
range. In order to be able to adap-t the eleastic behavior of
the diaphragm from the region of air entry to the outermost
edge thereof, the diaphragm can be of varying thickness.
With regard to the connection of the supp.-or~ ~dy:it
is recommended that the air feeding connection is a tubulure
provided, as the case may be, with transverse discharge open-
ings, to which the diaphragm is connected by means of clamps.
It is further recommended that , for instance, a round
diaphragm is so thickened at its central region that it can
be fastened on the supporting wing by means of a clamping
disc having a bead and a screw, and that it can be screw-
connected ~ith the air supply soc]cet.
A fastening of thediaphragm with the supporting body at
the outer rim calls for providing the diaphragrn with a cir-
cumferential sleeve surrounding the supporting wing as a
sealing sleeve, a groove being op-tionally provided in the
- sleeve and being engageable by a circumEerential clamp.
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When the supporting wing is of rectangular or polygonal
shape, it is recommonded that the same i.s connected, in the
direction of its pri.ncipal extension, with an open channel
as the air supply connection, in which case the diaphragm
S is connected with the supporti.ng w.ing via clamping straps.
t In particular in the case of large area aera-tion it is
advisable that the passages Eor -the ambient water will pro-
mote the uniformity of air distribution~
In order to facili-tate the positions of operation in
10 depth and for repair o* the device, inflatable and/ox sta-
tionary floating bodies are attached to the same.
With regard to the adjustability and the inclination of the
aeration face relat.ive to the liquid surface i- is to be
borne in mi.nd that the aeration face can be inclined relative
15 to the liquid surEace at an angle of up to -~ 90 or vaulted
and slewable.
Any double angl.e~ connection can be used, for instance
in the air feeding line in order to provide slewability.
The normally round or rectangular s.up~o~tingwin~s can be
20 optionally provided with throughholes of random shape.
Furthermore, the diaphragm may consist of woven or
knitted synthetic resin fabric, or the elastic diaphragm can
be a metal foil.
The diaphragm is provided with perfora-tions in the
~5 shape of holes or cuts of slot, star or cross shape through
which the air is introduced into the water in the form of
Eine bubbles. In the region of openings in the supporting
wing these perforations are preferably omitted. The perfor-
ations should be in staggered arrangement in order to impart
30 to the diaphragm the greatest possible stability.
The terms "deepest point" and "deepest limit" relate respect-
ively to the peak limits (point or line) and can be taken as
directed downwardly as well as upwardly.
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In a broad aspect, the present invention relates to a
device for the aeration of a liquid in an aeration tank,
comp.rising an air supply; a supporting body havin~ a center
of gravity with an aeration face having fixst perforations
therein, a central portion having air inlet means connected
to said air supply and a periphery being disposed slightly
higher than said center of gravity; a diaphragm of flexible/
airti.ght material covering said supporti:ng body and being
attached thereto in airtight fashion about said periphery,
said diaphragm having second perforations being out of
alignment with said first perforations, wherein air is fed
from said air supply into said central portion of said
supporting body, through said first perforations, between said
diaphragm and said supporting body, outwards towards said
periphery through said second perforations and with decreasing
pressure into said liquid to be aerated.
In another broad aspect, the present invention relates
to a device for the aeration of liquid in an aeration tank
comprising: a rigid supporting body of random shape bearing
an aeration face haviny first perforations therein, said
supporting body having a center of gravity and a periphery
being disposed slightly higher than said center of gravity;
a diaphragm of airtight material covering said supporting body
and having second pe.rforations in parts thereof out of
register with said first perforations; a frame structure
adapted for locking said supporting body in a chosen pOSitiOIl
in said aeration tank; an air supply adapted for feeding air
into said supporting body and substantially in the center of
gravity thereof, through said first perforations so as to
enter a deflecting ~one adapted to direct sa.id aix towards
said periphery and to pass that air between said diaphraqm and
said supporting body with decreasing pressure into said liquid
to be aerated.
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In a further broad aspectl the present invention relates
to a device for the aeration of a liquid in an aeration tank/
comprising: a rigid supporting body having an aeration face
with a first set of perforations therein, said supporting body
having a center of gravity and a periphery being disposed
slightly higher than said center of gravity; a diaphragm of
airtight material covering said supporting body, being
sealingly secured around the periphery thereof, and having
second perforations in parts thereof out of register with said
first perforations; and an aix supply connected to said
supporting body and adapted for feeding ai.r into said support
body through said first perforations and substantially in said
center of gravity, so as to direct said air towards said
periphery and to pass that air between said diaphragm and said
supporting body and through the perforations in said diaphragm
with decreasing pressure into said liquid to be aerated.
In another broad aspect, the present invention relates
to a process for the intermittent aeration of a liquid such
as waste water or the like medium in an aeration tank by means
of an aeration device arranged below the surface of the liquid
and comprising at least one supporting body having first
perforations therein, an air supply, and an elastic diaphragm
covering the supporting body, said diaphragm being of air-
tiyht material and having second perforations in the form of
punctures, slots or holes in parts thereof out of register
with said first perforations, as well as a frame structure
locking the supporting body in position, said supporting body
being rigid, self-supporting and air [is] being directed
substantially vertically onto said supporting body in at least
deflecting reach thereof, and substantially in the center of
gravity thereof or in series along a gravity line, the air
being deflected toward the periphery of said body, said
periphery being disposed slightly higher vis-a-vis said center
of gravity, said air then being passed between said diaphragm
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and said supporting body with decreasing pressure into the
water to be aexated, in an aerating plane being inclined with
regard to the water surface at an angle o:E up to ~90 and is
adapted to be swivelled for adjusting that angle.
In another broad aspect, the present invention relates
to a device for the intermittent aeration of a liquid in an
aeration tank, comprising a rigid support:ing body bearing an
aeration face having first perforations therein/ of random
shape, a diaphrag~ of a.ir-tight material covering said
supporting body and having second perforations in parts
thereof out of register with said first perforations, a frame
structure adapted for locking said supporting body in a chosen
position in the aeration tank, said supporting body having a
center of gravity and a periphery being disposed sliyhtly
higher than said c~nter of gravity, an alr supply adapted for
feeding air directed substantially vertically relative to said
supporting body and substantially in the center of gravity
thereof, so as to enter a deflecting zone adapted to direct
said air toward said periphery and to pass said air between
said diaphragm and said supporting body with decreasing
pressure into the water to be aerated, said aerating face
extending in a plane being inclined with regard to the water
surface at an angle of up to +90, and swivelling means
associated with said supporting body and adapted for
swivelling said body to adjust said angle, the static
resistance of said supporting body being determined, besides
the choice of material and the dimensioning of its thickness,
by the magnitude of the displacement of the level thereof,
situated at an angle of up to +90 between the deepest point
or deepest limit in the center of gravity or on a gravity
line, respectively, the inclination of said angle being
determined by the cross-sectional area of said aeration face,
leading from said deepest point or limit to said periphery.
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In connection with this latter mentioned aspect of the
present invention, it is preferred that said aeration face is
provided with an elastic coating and said diaphragm is a metal
foil with said second perforations filled with said elastic
coating when said diaphragm is in a rest position.
It is also a preferred embodiment if said aeration face
is provided with an elastic coating and said diaphragm is a
hard plastic foil with said perforations filled with said
elastic coating when said diaphragm is in a rest position.
Moreover, it is desirable that said aeration face is
provided with a plurality of elevations and said diaphragm is
a metal foil with said second perforations filled with said
elevations when said diaphragm is in a rest position for
cleaning said second perforations.
Furthermore, it is also desirable that said aeration face
is provided with a plurality of elevations and said diaphragm
is a hard place foil with said second perforations filled with
said elevations when said diaphragm is in a rest position for
cleaning said second perforations.
In the latter two mentioned aspects of the present
invention, it is particùlarly advantageous if the elevations
are sonical pins
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1321428
rrhe process according to the invention and the device
for carrying o~ ~he~ sa~ thus fully comply with -the initi-
ally set task.
BRIEF DESCRIPTION GF T~IE DRAWINGS
S The process according to the invention will be explained in
more detail in connection with the accompanying drawings
which show devices suitable for carrying the process out in
practice~ In these drawings
Fig. 1 shows a top view of a first embodiment of the
device according to the invention, of rounded shape;
Fig. 2 is a~sectional view ta]cen along a plane indicat-
ed in Fig. 1 by ~
Fig. 3 is a t-op view of another embodiment, of rectan-
gular shape;
Fig. 4 is a cross-sectional view of the same embodiment
along a plane indicated in Fig. 3 by IV-IV;
Fig. 5 shows in cross-sectional view a detail of the
air supply and the deflecting zone with the air being fed
from above;
Fig. 6 shows in cross-sectional view a detail of the
air supply and deflecting ~one, with the air being fed from
below;
Fig. 7 is a cross-sectional view, taken in the region
of the gravity line, of a channel-shaped air supply;
Fig.8 is a top view of a further embodiment of the de-
vice according to the invention, of round shape;
~ Fig. 9 is a cross-sectional view of the same embodiment
; taken in a plane indica-ted by IX-IX in Fig. 8;
` Fig. 10 is a top view of yet another embodiment of the
device aGcording to the invention; and
Fig.ll is a cross-sectional view of the same embodim~nt
~- taken in a plane indicated by XI-XI in Fig. 10.
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DETAILED DESCRIPTION OF THE EMBOD:[MENTS SHOWN
IN T~IE DRAWINGS
The air feeding lines 1 represen-ted in the Figures 1, 2 and
have a supply socket which is directed rom above toward
a rigid supporting wing 2 and arranged as a rule at the cen-
ter of gravity 10, which is in general fastened to the center
of gravity of the face, and which, as shown in the drawings,
is provided in a deflecting region 3 with transverse dis-
charge openings 1.1~
On the supporting wing 2 there lies an elastic perfor-
ated diaphragm 4 which is affixed along its peri.phery 12 by
means of a clamping device 5, and at the air supply socket
by means of a clamping collar 6. In the case of the embodi-
ment of Fig. 6, a soclcet, for the supply of air, and provid-
ed with an internal threading, is connected from below to
the supporting wing 2, the par-tial region of the wing 2 be-
ing surrounded by the socket being in open condition. The
connection with the diaphragm ~ is effected via a clamping
strap 7 fastened in alignment with the upper end of the
socket.
The embodiment shown in Figures 4 and 5 isa rectangu-
lar aerator provided with a channel 1.2 open toward the sup-
porting wing 2 and along the principal extension of the lat-
ter which, as a rule r coincides with a gravity line 11
thereof, into which channel air is introduced at a random
site.
In the peripheral region the channel 1.2 is closed to-
ward the outside, and the connection with the diaphragm 4
is effected by means of clamping straps 7 which are arranged
flush with the supporting wing face. The static stability of
the supporting wing 2 depends, apart from the choice of ma-
~; terial and the dimensioning of its thickness, from the amount
of level displacement 13 between the depth limit at the cen-
ter of gravity 10 or a gravity line 11, on the one hand, and
the periphery 12 of the supporting wing 2, on the other hand.
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The shape of the inclination can be ta)cen Erom the out-
line of the cross section th:rough the supporting wing; it
extends generally in straight lines, bu-t can ~e devised in
the direction of the heightened region thereoE of circular/
concave/convex shape or of ci.rcular/calotte shape.
The device can be provided with at leas-t one in-
flatable or rigid floating body 8,9, so that the aerator can
be transferred to the water surface even in a filled tank.
The elastic floating bodies are filled via a pipe or hose
line prior to the removal of the aerating device from the
tank, and will therefore float to the water surface after an
arresting device holding the aerating device in the tank has
been removed.
The embodiment of a round aerator shown in Figures 8
and 9 comprises a diEferent embodiment of the air supply l
which comprises a socket directed from below against the
rigid supporting wing 2 arranged as a rule at the center of
gravity lO and being generally attached at the center of
gravity of the wing. The supporting wing 2 is covered by the
elastic, perforated diaphragm 4 which is connected with the
rigid supporting wing along its periphery 12 by means of a
sealing sleeve 14. This sealing sleeve 14 has a circumferen-
tial groove 15 in which there is lodged a clamping ring 16.
In its central region, the diaphragm 4 is provided with a
hub 17, thickened axially, where the diaphragm is connected
with the rigid supporting wing 2 by means of a clamping disc having a
.kead 1~ and screw 19. The ref.no.1.3 indicates the air-inlets opcnings.
In the case of an air supply device l as shown in Fi-
gures lo and ll~, a thread-bearing socket is provided with an
30 internal annular flange 20 on which the supporting wing 2
toge.ther with the diaphragm 4 comes to rest, being held in
position thereon by means of an internally threaded collar
21 and a pressure ring 22.
Means for adjusting the position of the aerating de~ice
are not shown.
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1 32 1 428
This position is fixed by means of pull rods, ropes,
articulated joints or other ]cnown installations, with the
inflatable floating bodies having finally the advantage that,
with an equipoised arrangement and an e~ual degree of fill-
ing, the level of the aerator can be practically floatinglyadjusted at last without carrying elements. In order to make
possible, in a given case, a circula-tion oE the water cur-
rent through the aeration plane, throughholes can be provid-
ed in this plane, for instance, in the region oE the air
supply 1, which throughholes must be sealed in between the
carrier wing and the diaphragm in order to prevent water
from penetrating therebetween.
Finally it .should be mentioned that the rigidity of the sup-
porting wings can be augmented, as the case may be, by em-
bossed indentations, in which cas~ covering of the indenta-
tions by the diaphragm ~ must be taken into account when
producing the perforations therein.
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