Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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The invention relates to an apparatus for purifying service water,
more particularly for regenerating polluted water, with the aid of a water-jct
pump which discharges air drawn in with the water, through an air-suction pipe,
into a screen-like conduit, both of which runjointly for acertain distance below
the surface of the water.
Apparatuses of this kind are used for the biological purification of
sewage and for the regeneration of bodies of water which are largely polluted
due to lack of oxygen. Apparatus is ]cnown (French Patent 13 77 571) in which
the mixture oE water and air produced by a water-jet pump are held, for a period
of time, in a mixing pipe, so that the forced passage of the discharge jet in-
creases the period of residence of the air bubbles in the water. However, this
does not greatly increase the period of residence, and the amount of oxygen in-
troduced into the water is therefore inadequate. The reason for this is that a
relatively high flow velocity obtains inthe screen~like cover designed as a
mixing pipe with a diffuser. The period of residence of sewage and air therein
is therefore relatively short.
Thus the disadvantage of the known apparatus for the purification of
service water is that the individual air bubbles are usually screened very shor-t-
ly after they leave the water-jet, where upon they rise to the surface. Another
disadvantage is that in silted waters, the whole appara-tus rests upon the bottom~
so that mud is stirred up by the intakes of the water-jet pump, is drawn in, a~ld
thus leads to premature contamination of the line.
The air bubbles rapidly come together and then rise, as large bubbles,
along the surface of the air-permeable wall, to the surface of the water. In
spite of this, this type of water purification causes less damage to the en-
vironment than direct injection of compressed air into polluted bodies of water,
since there is no need for compressors and the like equipment along the shore-
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line.
It is the purpose of the invention to provide a water-purification
apparatus which increases the period of residence of the air-bubbles, is inde-
pendent of irregularities along the bottom of the body of water, is at all times
located at a definite level below the surface of the water, and is not harmful
to the environment.
According ~o the invention, this purpose is achieved in that the con-
duit is of double-wall design and is arranged to slope towards the surface of
the water, the inner part of the conduit being permeable to air, whereas the
outer part thereof is impermeable to air, and in that the water-jet pump and the
double-walled conduit are associated with a support-structure of tubular frames
comprising vent-valves and flooding-valves.
l'he air drawn in by the water-jet pump, and divided into very fine air
bubbles, is gulded, partly under the air-permeable inner part of the line and
partly, after passing through the said inner part consisting, for example~ of a
fine-meshed net, under the air-impermeable outer part of the line, to the end
thereof, thus ensuring a satisfactory transfer of air to the stabilized part of
the conduit. This substantially increases the period of residence.
The support-structure, consisting of tubular frames adapted to be
flooded, may be located at a distance below the level of the water such that
water supplied to the suction intakes of the water-jet pump does not stir up
the mud on the bottom. The movement of water inside the apparatus also has no
negative effect upon the apparatus itself, since any sludge deposited upon the
bottom of the body of water may be churned up at the outlet from the apparatus,
by the flow of water. The advantage of this is that the apparatus may be op-
timally located regardless of the configuration of the bottom and of the degree
of silting. In addition to this, there is very little harm to the environment
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since the drive for the water-jet pump may be arranged in the body of water it-
self, so that only the supply-cable and the air intake pipe are visible above the
level of the water.
For the purpose of increasing the period of residence it is further-
more desirable for the inner part of the line to be made of fine-meshed net, or
of a plurality of fine-meshed nets, the size of the mesh increasing towards the
outer part of the line. The individual nets provide support for each other and
make it difficult for the air bubbles to agglomerate. In fact the said bubbles
frequently adhere to the webs of the nets for a certain length of time and are
thus swept by the water. The required satisfactory transfer of o~ygen is achiev-ed by this intimate and frequent contact.
The predetermined slope of the double-walled pipe may, if necessary,
be varied and adapted to the requirements by partitioning the upper and lower
tubular frames into a plurality of corresponding sections. Thus any desired
slope may be imparted to the apparatus as a whole by flooding or evacuating in-
dividual sections, without making any structural changes. This also has the
advantage that the whole apparatus may be lowered or raised faster if required.
To this end the individual sections are equipped according to the invention withvent- and flooding valves.
According to one advantageous configuration of the invention, the vent-
valves are associated with the upper tubular frame and the flooding valves with
the lower. Although this has the slight disadvantage that dirt may enter the
structure through the flooding valves, it has the advantage of faster flooding.
In this connection, the deep-down flooding valves may be operated mechanically
by linkages from the surface of the water and this keeps down the control costs.As a simple means of keeping the support-structure in equilibrium, it
is desirable to equip the upper tubular ~rame, in the vicinity of the water-jet
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pump, with a series of transverse tubes o a diameter corresponding to that of
the tubular frame. The weight acting upon t]is part of the structure is thus
equali~ed without any difficulty.
The most favourable possible weight distribution is achieved in the
configuration according to the invention in which the compressor, pump and motor
constituting the water-jet pump are arranged axially one behind the other. Prom
the point of view of flow technique and power consumption, this arrangement has
the advan~age that the water drawn in passes to the water-jet compressor with no
change in direction.
In order ~o reduce the noise produced by drawing in air, it is pro-
posed, according to the invention, to fit a silencer to -the free end of the air-
intake pipe. This reduces the noise produced by the apparatus according to the
invention to practically nil, since the water-jet pump itself, with its drive,
is submerged in the water. Howeve-r, the motor, or even the motor and the pump,
may be located above the upper tubular frame, if ~his is regarded as necessary
and advantageous from the point of view of maintenance.
The vent- and flooding valves in each section are preferably arranged
at the junctions thereof. This makes the valves easily accessible if, according
to another configuration of the invention, the upper tubular frame is fitted, in
the vicini~y of the said junctions between the sectionsS with brackets for a
grating. Since the apparatus for purifying service water is usually located
directly below the surface of the water, the gratings are above the water and may
therefore easily be reached with dry feet. Since the length and width of the
apparatus provide adequate stability~ the brackets may be made to extend, so that
they are still above the surface of the water if the apparatus is submerged to
a greater depth.
Since, as far as possible, the water containing the least amount of
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oxygen is to be gasified or enriched with oxygen7 it is desirable to connect thesuction side of the water-jet pump, through a hose line, to a suction station
arranged on the bottom of the body of water. In this way, the suction station
always supplies the apparatus with water containing little oxygen, without lower-
ing the apparatus as a whole.
With a suction station arranged on the bottom, the intake of sludge
and too heavily contaminated water is prevented, according to the invention, by
fitting the said station with an upwardly directed inlet funnel arranged in a
box-like housing with a vertically arranged coarse screen and a horizontal fine
screen behind it. Water fed to the intake funnel is thus largely freed from con-taminants. Special guidance of the water ensures that the water drawn in does
not create undue disturbance.
According to the invention, the purifying effect promoted by the supply
of oxygen is increased by arranging, in the body of water to be cleaned, a
plurality of water-jet pumps and double-walled lines located in tubular-frame
support-structures in such a manner that they communicate with each other in
drawing in and discharging water and, if necessary, producing and maintaining a
water-circulation in the body of water. In stagnant water, this produces faster
mixing with gas-enriched water, thus accelerating biological purification.
The period of residence of air bubbles, drawn in by the water-jet pump,
within the double-walled pipe may be increased, according to the invention, in
that either the front part of the interior of the pipe, serving as a flow duct,
is adapted to pivot vertically, or the tip of the exterior of the pipe, serving
as a cover, is adapted to pivot vertically. It is also conceivable to combine
the two arrangements. This makes it possible to control the direction of the
jet of water leaving the apparatus, and thus to adjust it as required.
It is usually desirable to leave the apparatus for some time at a
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specific location in the body of water to be purified. In order to make this
possible if the water is flowing at a specific velocity, the upper tubular rame
has anchoring eyes at its ends by means of which the apparatus may be secured on
land, or to the bottom of the body of water, by means of anchors or weights and
suitable cables.
The invention is distinguished, more particularly, by the fact that
the period of residence of air bubbles is substantially longer and the transfer
of oxygen from the bubbles to the water ~o be purified is considerably improved.
The advantageous method of operation achieved by a water-jet pump associated
with a double-walled conduit, even when used in highly contaminated and silted-
up bodies of water over long periods of time, is thus assured, and the necessary
drive-units and equipment producing noise are arranged and designed in such a
manner 2S ~0 avoid harming the environment. The apparatus is furthermore easy
to maintain and can be adapted without difficulty to varying requirements.
Th0 invention will now be described in greater detail with reference
to the accompanying drawings in which:
Figure 1 is a longitudin~l section of purifying apparatus according to
the present invention;
Figure 2 is an enlarged view of a portion of Figure 1 showing the
drive-unit;
Figure 3 is a head-on view of the apparatus in the vicinity of the
drive-unit;
Figure ~ is a cross-sectional view of the apparatus;
Figure 5 is an enlarged plan view of a detail of ~igure 1;
Figure 6 is an enlarged view of a portion of Figure 1 showing the
suction-station;
Figure 7 is a plan view of the suction station of Figure 6.
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In Figure 1, the floating water-purification apparatus is referenced
1 in general. It consists of a support-structuer 2 which carries a water--jet
pump 3 and double-walled pipe or conduit 4 ancl which is connected to a suction-
station 5 resting upon the bottom of the kody of water 6.
Support-structure 2 comprises an upper tubular frame 7 and a lower
tubular frame 8, both made of pairs of hollow tubes of the same diameter. The
hollow tubes of lower frame 8are parallel and connected togetheT by transverse
tubes 9. For the purpose oF forming a continuous air chamber, tubular frames 7,
8 are connected together by vertical tubes lO.
As may be gathered from Figures 2 and 3, among others, whereas the two
parallel tubes of frame 8are connected together by transverse tubes 9, the two
parallel tubes of upper tubular frame 7 are connected together by transverse
braces 11, so that the entire apparatus 1 is in equilibrium. Frames 7, 8 are
partitioned~ approximately centrally, by joints 14, thus producing sections 15,
16 ~Figure 5). Each section is fit~ed wi~h vent-valves 12, 12' and flooding
valves 13, 13' (Figure 1) and each sec~ion of the combined frame 7, 8 may there-
fore be flooded or evacuated simultaneously or at different ti~es.
Secured to upper tubular frame 7, by welding for example, are brackets
for the support of a grating 1~ ~Figure 4). As shown in Figures 1 and 5,
valves 12, 12', 13, 13' are easily accessible through the grating in the vicinity
of junction 14~ if the valves need to be operated, or for maintenance purposes.
As shown in Figure 2, water-je~ pump 3 consists of a pump 20, prefer-
ably an electrically driven motor 21, and a compressor 22. Air-suction pipe 23
enters between the said compressor and pump, through which the required oxygen
or air is drawn in~o the jet of water. Fitted to free end 25 of air-suction pipe
23 is a silencer 24, the purpose of which is to reduce the a~.ount of noise made
by air being drawn in. Pump 20, motor 21 and compressor 22 are arranged one
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behind the other, thus producing a satisfactory weight distri~ution. Arranged
in the vicinity of water-jet pump 3 and intercomlecting tubes 7 is a series oE
transverse tubes 9', 9" and 9"' for the purpose of distributing and equalizing
the weight.
Floating water-purification apparatus 1 may easily be anchored in a
predetermined position by securing to anchoring eyes 27, shown in Figure 3,
cables secured to the shore or to weights.
Double-walled pipe or conduit 4 consists of an air permeable inner
part 28 and an air impermeable outer part 32 as shown in Figures 3 and 4.
Inner part 28 is formed as a mesh with aplastic lining 30, so that air bubbles
expelled by compressor 22 take some time to pass through the inner part and to
collect upon corrugated outer part 32. This cor~lgation impedes the formation
of large air bubbles rising quickly to surface 34 of the water. A comparison
of Figures 3 and 4 shows that the cross-section formed by outer part 32 of the
conduit increases towards the mouth 33 thereof, i.e. outer part 32 of the line
slopes towards surface 34 of the water. Mouth 33 of outer part 32 of the line
is pivotable, so that air bubbles arriving here may again be held up and be
forced into the water.
The front portion of inner part 28 of the line is also pivotable in
order to impart a specific direction to the flow of water. As may ~e gathered
from Figure 1~ the front portion is directed towards the bottom of the body of
water~ so that the oxygen-enriched flow of water is forced to flow along the
bottom, ~hus displacing, or mixing with, the strata of water not yet enriched
with oxygen. This optimizes the biological purifying effect.
Intake end 36 is connected by means of a hose line 35 to a suction
station 5. It consists of a box-like housing 40 in which the inlet funnel con-
nected to hose line 35 is arranged in such a manner that the opening thereof is
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directed towards surface 34 of the water. Housing 40, seated upon a platform 39
resting upon the bottom, encloses inlet funnel 38, so that the water is forced
to enter the housing through platform 39, through a co~rse screen 41 and then
through a fine screen 42, the coarse screen being spaced from housing 40 by sup-
ports 43. It may be gathered from Figures 6 and 7 that suction station 5 pro-
vides a relatively uniform flow of water, so that few contaminants reach the area
between the two screens.
