EP0912222A1

EP0912222A1 - System for sucking sludge at the bottom of a sedimentation pond

Info

Publication number: EP0912222A1
Application number: EP97931829A
Authority: EP
Inventors: Alain Delafosse; Christian De Gelis
Original assignee: d'Etudes et de Realisation pour l'Environnement et le Procede Ste
Current assignee: d'Etudes et de Realisation pour l'Environnement et le Procede Ste
Priority date: 1996-07-01
Filing date: 1997-06-27
Publication date: 1999-05-06
Also published as: FR2750345A1; WO1998000217A1; FR2750345B1

Abstract

A guide rail (7) bears a longitudinal row (12) of identical substantially cylindrical pins (13), fixed with respect to the bottom (8) of the pond, arranged parallel to a common direction according to a predetermined pitch. A carrier (2) comprises a driving pinion having toothing of a sprocket type formed by teeth designed to mesh with the said pins (13), the radial length of the teeth being predetermined such that the free end of each tooth penetrates between two adjacent pins (13) at least up to the point where the space between the said pins (13) is the smallest.

Description

SYSTEM FOR SUCTION OF SLUDGE AT THE BOTTOM OF A DECANTING BASIN

The present invention relates to a system for sucking sludge from the bottom of a settling tank.

Many systems of the aforementioned type are known. We know for example, from FR-A-2 501 055, a

10 system comprising a carriage movable in a longitudinal direction of the basin and supporting a transverse sludge suction pipe adapted to be connected to sludge suction means located outside said basin, means forming longitudinal rail of

15 guide fixed to the bottom of the basin, and drive means integral with the carriage and adapted to engage the guide rail to advance said carriage from one end to the other of the basin alternately in one direction and in the other, along 0 of said guide rail.

The drive means described comprise a set of jacks and jaws which make it possible to advance the carriage step by step along the guide rail.

Such a system permanently requires the presence of an air compressor, and, in practice, of two compressors, in order to be able to ensure continuous operation. This system is therefore relatively expensive in terms of investment cost and costs.

^" () operating. In addition, this system is relatively reliable, but requires relatively high maintenance costs. Finally, this system does not make it possible to locate the trolley at the bottom of a basin in the event of said trolley being stopped , resulting in losses of

"ô time to locate this trolley before intervening in the event of its breakdown. The present invention aims to remedy the drawbacks of known systems, and to provide a system of the aforementioned type, extremely reliable, very economical to operate, capable of making it possible to locate, at any time, the carriage at the bottom of the basin.

According to the present invention, the system of the aforementioned type is characterized in that it comprises at least one longitudinal row of substantially cylindrical identical fingers, fixed relative to the bottom of the pelvis, arranged parallel to the same direction in a predetermined pitch, and in that the carriage comprises at least one driving pinion having a chain-type toothing formed by teeth adapted to mesh with said fingers, the radial length of the teeth being predetermined so that the free end of each tooth penetrates between two adjacent fingers at least to the point where the gap between said fingers is the smallest.

It was previously considered, in this technical field, that a rack and pinion drive was unusable for driving the carriage of a sludge suction system, given the risks associated with the permanent presence of sludge and debris of all kinds entrained by them, pebbles, metal wires, various materials, etc. likely to hinder or even prevent the proper functioning of the pinion and rack mechanism.

Now, the Applicant has discovered that these drawbacks could be avoided by using a chain-type toothing for the drive pinion, formed of relatively long teeth adapted to mesh with fingers of the aforementioned type, arranged in the manner of rollers. 'a tight chain.

Indeed, a tooth of a pinion penetrating between two adjacent fingers on one side of these fingers, drives out the other side the materials and debris located between these two fingers, which ensures the cleaning of the chain.

According to an interesting version of the invention, the fingers are arranged vertically projecting relative to the upper surface of the guide rail, and the carriage comprises at least three pinions meshing with the fingers, two pinions being arranged on the same side of the fingers and a pinion being arranged on the other side of the fingers substantially halfway between the two other pinions.

Such drive means make it possible to exert a large driving force of the carriage to overcome or break any obstacles, to clean the spaces between the fingers, and to ensure good alignment of the carriage with respect to the row of fingers.

According to an advantageous embodiment of the invention, each pinion is driven by a gearmotor with alternating output controlled electronically, supplied with direct current at low voltage, the three gearmotors being supplied in parallel.

A reliable and economical source of energy is thus used, allowing precise and efficient control of the operation of the truck.

According to a preferred embodiment, each gear motor is equipped with a revolution counter device.

It is thus possible, at any time, to know precisely the position of the carriage along the guide rail.

Other features and advantages of the invention will appear in the detailed description below. In the appended drawings given solely by way of nonlimiting examples: FIG. 1 is a schematic perspective view of an embodiment of the system according to the present invention, - FIG. 2 is a diagram illustrating the configuration of the carriage of FIG. 1 in the middle and at each of the ends of its trajectory, - Figure 3 is a partial elevational view, with parts broken away, of the carriage of Figure 1;

- Figure 4 is a bottom view of the carriage of Figure 3;

- Figure 5 is an enlarged partial view of a detail of Figure 4; Figure 6 is an enlarged front view taken from the left of Figure 3; - Figure 7 is a cutaway view along

VII-VII in Figure 3;

- Figure 8 is an enlarged partial view of a detail of Figure 1, -

- Figure 9 is an enlarged view of a detail of Figure 6.

In the embodiment shown schematically in Figure 1, the system 1 for sucking sludge at the bottom of a settling tank, comprises a carriage 2 movable in a longitudinal direction of the tank indiçn-ted by the arrow 3 and supporting a transverse tubing 4 sludge suction adapted to be connected by a flexible pipe 6 to means 5 for sludge suction located outside the basin. The system 1 also includes a longitudinal guide rail 7 fixed to the bottom 8 of the basin by any fixing means shown diagrammatically at 9, for example feet fixed by screws to the bottom 8 of the basin. The system l also comprises drive means integral with the carriage 2 and adapted to engage with the guide rail 7 to advance the carriage 2 from one end 10 to the other end 11 of the basin, alternately in one direction. and in the other, along the guide rail 7 (see Figure 2).

According to the invention, the system 1 comprises at least one longitudinal row 12 of substantially cylindrical identical fingers 13, fixed relative to the bottom 8 of the basin, arranged parallel to the same direction at a predetermined pitch, as shown diagrammatically in FIG. 5.

As shown diagrammatically in FIG. 5, the carriage 2 comprises at least one drive pinion 14 having a chain-type toothing formed by teeth 15 adapted to mesh with the fingers 13. The radial length of the teeth is predetermined so that the end free 16 of each tooth 15 penetrates between two adjacent fingers 13 at least to the point where the gap between said fingers 13 is the smallest. In the example shown which corresponds to the normal situation of a pinion cooperating with a chain, each tooth 15 has a radial length substantially equal to the diameter of the fingers 13.

In the embodiment shown in FIGS. 1 to 9, the fingers 13 are arranged vertically projecting relative to the upper surface 17 of the guide rail 7. The carriage 2 comprises three pinions 14 meshing with the fingers 13. Two pinions 14 are arranged on the same side of the row 12 of the fingers 13, and the third pinion is arranged on the other side of the row 12, substantially halfway between the two other pinions. In this example, each pinion 14 is driven by a geared motor 18 with electronically controlled AC output, supplied with low voltage direct current, for example 12 volts. The gearmotors 18 are, for example, commercial gearmotors used to actuate windscreen wipers for vehicles such as public works vehicles. These are for example 4BE type gearmotors manufactured by VALEO, which are capable of supplying a torque at five revolutions / min of 6Nm, comprising a single reduction stage consisting of a worm and a wheel. Such a geared motor, supplied with 12 volts, consumes a current of 1.2A when empty and can withstand a constant maximum current of 7A. We know that such a gearmotor is extremely reliable, and is calculated for example for a guaranteed operating time of at least fifteen thousand hours. Being manufactured in large series, such a geared motor is also inexpensive.

The stator of the electric motor of such a geared motor is formed of ferrites and produces a permanent magnetic field. The rotor has coils in which flows the current which is brought by the collector and which generates a magnetic field transforming the electrical energy into mechanical energy. The direction of rotation of the motor is determined by the polarity of the connection of the power supply, and the reversal of this connection causes a reversal of the direction of rotation. Such an engine is capable of remaining powered while being blocked, which facilitates the control of the carriage (see below).

As a result, it is possible to feed three gearmotors in parallel without any precaution, the three motors automatically synchronizing one with respect to the other two.

Each gearmotor is equipped with a revolution counter device: it is thus possible to count the revolutions in a control cabinet 46 to know at any time and precisely the position of the carriage 2 at the bottom of the basin.

The control cabinet 46 also includes all the conventional electronic means for electronically controlling the supply of the geared motors 18 and reverse the feed direction and the direction of rotation of these at the end of the stroke.

In the embodiment shown, the carriage 2 comprises a central body 19 carrying the three drive pinions 14. The central body 19 is slidably mounted on two longitudinal slides 20 carried at each of their longitudinal ends 21, 22 by a support member 23 mounted on wheels 24.

As shown in particular in Figures 3, 4, 6 and 9, each support member 23 has two wheels

24 adapted to roll on the upper surface 17 of the guide rail 7 on either side of the row 12 of fingers 13.

Each support member 23 comprises means for bearing transversely on one or the other of the lateral faces 25, 26 of the guide rail 7.

It can be seen in particular in FIGS. 6 and 9 that the guide rail 7 is, in the example shown, constituted by a tube 27 of square section, surmounted by a flat 28 carrying the fingers 13.

Each support member 23 extends on either side of the square tube 27 substantially to the lower part of said tube.

Each support member 23 has its end opposite to the central body 19 of tapered shape in plan view (Figure 3) and in profile view (Figure 4). The end face 29 of each support member 23 has an opening 30 through which the rail 7. The side edges 31 and 32 of the opening 30 can bear on the corresponding side face 25, 26 of the tube 27 to align if necessary the carriage 2 in the longitudinal direction 3.

This central body 19 also has an opening 50 for the passage of the rail 7 (see FIG. 7). The slides 20 pass through the central body 19 on either side of the opening 50 at the level thereof. A compression spring 33 is mounted around each slide 20 between the central body 19 and each of the support members 23. The purpose of the springs 33 is above all to avoid an impact of the central body 19 on a support member 23 and to make progressive l 'drive force produced by the gearmotors 18 at the end of travel of the carriage 2 or in front of an obstacle.

The transverse slurry suction pipe 4 is carried by the central body 19. In a conventional manner, the pipe 4 has on either side of the central body 19 two bends in opposite directions making it possible to bring the arms 4a and 4b of this tubing as close as possible to the bottom 8 of the basin. Chatjue arm 4a, 4b has at its free end a wheel 34 or a set of wheels for rolling on the bottom 8 of the basin. Each arm conventionally comprises sludge suction holes 35. A deflector 36 can be welded to the arm 4a, 4b between two adjacent holes 35.

In the example shown, the transverse tube 4 is pivotally mounted on the central body 19. The tube 4 is mounted on a hollow support 37 in the form of an inverted bowl comprising, along its outer edge, a flange 38 bearing on the upper surface 39 of the central body 19. The hollow support 37 communicates with the tube 4 through a hole 37a.

As shown in Figures 7 and 8, the flange 38 is pressed against an annular seal 40 of anti-friction material, for example Teflon (registered trademark), by spacers 41 pressed against the surface 39 by springs 42 which are each put in compression by a screw 43. It is thus possible to adjust at will the resistance opposed by this mounting to a pivoting of the suction pipe 4 relative to the central body 19 in the case where one of the arms 4a, 4b encounters an obstacle . Other known mounting methods can also be used.

To avoid the accumulation of sludge on either side of the guide rail 7, two suction tubes 44, 45 communicating with the interior of the hollow support 37, extend substantially vertically towards the bottom 8 of the basin and open out at the level of the guide rail 7 on either side of it (see FIG. 7).

The carriage according to the invention is connected to the control cabinet 46 containing an automaton for controlling the movement of the carriage, by a flexible cable 47 comprising four conductors, two conductors for the supply current of the motors of the gearmotors 18, and two conductors for bringing back to the electrical cabinet 46 a signal at each revolution of the motors. The flexible cable 47 with four conductors is thus compact. It is preferably housed inside the flexible sludge suction pipe 6.

Conventionally, a lifter is provided, shown diagrammatically at 48, for gripping the arms 4a, 4b of the suction pipe and bringing the assembly of the carriage 2 to the surface for examination or maintenance.

The operation of the system according to the invention is as follows. When the carriage 2 is in its normal position astride the guide rail 7, the pinions 14 meshed with the corresponding fingers 13 of row 12, it suffices to send low-voltage current through the cable 47 to rotate the pinions 14 in a certain direction and move the carriage in the corresponding direction, for example to the left in FIGS. 1, 2, 3 and.

When the support member 23 at the left end of the carriage abuts on the end 10 of the pelvis, this support member is blocked, while the body central 19 continues to advance towards the end 10, compressing the springs 33.

When the central body 19 comes into abutment against the support member 23, the geared motors 14 are blocked. The intensity of the current flowing in the three motors increases up to a maximum threshold controlled by the cabinet 46. When this maximum intensity threshold is reached, the cabinet 46 commands the reversal of the direction of the current to rotate the pinions 14 in the opposite direction to the previous one.

The carriage 2 therefore departs in the opposite direction, to the right in FIGS. 1, 2, 3, 4. The position of the central body 19 on the slides 20 does not matter. The central body 19 can remain against the support member 23 with which it is in contact, which corresponds to maximum stability in the longitudinal direction.

If the carriage 2 encounters an obstacle of sufficient strength to block the corresponding support member 23, then the central body 19, the intensity increases up to the aforementioned maximum threshold detected by the cabinet 46 which controls a reversal of the direction of movement of the carriage and mark, from the number of engine revolutions, the exact location of the obstacle to allow intervention on said obstacle. In general, the tapered shape of the end of the support members 23 is sufficient to remove a good part of the obstacles liable to hinder the advancement of the carriage 2.

If one of the arms 4a, 4b of the suction pipe 4 encounters an obstacle, the pipe 4 will pivot relative to the central body 19 so as to avoid the obstacle. This pivoting of the tubing 4 can be easily detected in the cabinet 46 to identify an alarm. When the carriage arrives at the corresponding end 10, 11 of the pelvis, the arm 4a, 4b which has not encountered the obstacle and which is located therefore in front of the carriage comes first into abutment against said end 10, 11, which causes pivoting in the opposite direction of the tube 4 which substantially resumes its initial transverse position. We have thus described a system for sucking sludge, particularly simple, reliable and very economical to operate.

By way of example, the applicant has produced a prototype comprising a rail which is a square tube 40 mm in side carrying fingers of diameter 5 mm, arranged in a pitch of 8 mm. The fingers have a height of about 15 mm, and the pinions have a height of about 14 mm to mesh with the greater part of the length of the fingers 13. The slides 20 can have a relatively large length, for example of the about 80 or 100 cm, to give the carriage 2 excellent stability in the longitudinal direction. The stability of the carriage 2 in the transverse direction is ensured by the rollers 34 at the end of the arms 4a, 4b of the spiral tube 4.

Despite the existing prejudice against the possible use of a rack to control the advancement of the carriage, due to the risk of blockage by mud, gravel, various debris, the space between two adjacent teeth of the rack , the present invention describes a carriage using a particular rack, on which meshes at least one particular pinion adapted to said rack, so as to spread or break said debris as far as possible. In addition, the detection of a blockage of the carriage in the electrical cabinet by monitoring a maximum intensity threshold which can be easily supported by the gearmotors driving the pinions, allows extremely reliable and flexible operation of the system according to the invention. , without risk of breakage in case presence of an obstacle resistant to the force developed by the pinions.

No particular precaution is necessary for the power supply of the gearmotors which synchronize automatically with each other. This allows the system to operate normally even if some fingers are broken.

Of course, the present invention is not limited to the embodiment which has just been described, and it is possible to make numerous changes and modifications thereto without departing from the scope of

1 invention.

Provision can thus be made for placing the fingers 13 in a direction different from that described, for example fingers arranged horizontally, or fingers arranged vertically under the guide rail.

It is also possible to provide several rows of fingers.

One can also modify the guide means of the different parts of the carriage relative to the guide rail.

Finally, the electrical energy to power the gearmotors could be replaced by another source of energy, provided that means are provided to detect a resistance opposing the advancement of the carriage and to control, in such a case, a reversing the direction of travel of this carriage to avoid any risk of breaking or simply deforming an element constituting the drive kinematic chain of the carriage. There must therefore be at least one motor pinion 14 driven by a motor means with two directions of rotation, means being provided for detecting a resistance to the advance of the carriage exceeding a predetermined threshold and for reversing in this case the direction of rotation of said means. engine. At least one slide 20 is required, and at least one spring 33 mounted between the central body 19 and each support member 23.

The embodiment described above is perfectly suited to a modular embodiment. it is possible to mount several central bodies 19 which may or may not be identical, on the same set of slides of great length, to drive a tube of great length adapted to a very large settling tank.

The system described above can be immediately transposed to a circular, not rectangular, settling tank. Just replace the words

"longitudinal direction" with the words "tangential direction".

The central body 19 is advantageously filled with resin to drown the geared motors 18.

Claims

1. System (1) for sucking sludge at the bottom (8) of a settling tank, this system (1)

5 comprising a carriage (2) movable in a longitudinal direction (3) of the basin and supporting a transverse tubing (4) for sludge suction adapted to be connected to means (5) for sludge suction located outside said basin, means (7) forming a rail

H) longitudinal guide fixed to the bottom (8) of the basin, and drive means integral with the carriage (2) and adapted to come into engagement with the guide rail (7) to advance said carriage (2) by an extremity

(10) to the other (ll) of the pelvis alternately in a

15 direction and in the other, along said guide rail (7), characterized in that it comprises at least one longitudinal row (12) of substantially cylindrical identical fingers (13), fixed relative to the bottom (8) of the pelvis, arranged parallel to the same direction

20 according to a predetermined pitch, and in that the carriage (2) comprises at least one driving pinion (14) having a toothing of the chain type formed by teeth (15) adapted to mesh with said fingers (13), the radial length teeth (15) being predetermined so that

The free end (16) of each tooth (15) penetrates between two adjacent fingers (13) at least to the point where the distance between said fingers (13) is the smallest.

2. System according to claim l, characterized in that each tooth (15) has a radial length

30 substantially equal to the diameter of the fingers (13).

3. System according to claim 1 or 2, characterized in that the fingers (13) are arranged vertically projecting relative to the upper surface (17) of the guide rail (7), and in that the

3 carriage (2) comprises at least three pinions (14) meshing with the fingers (13), two pinions (14) being arranged on the same side of the fingers (13) and a pinion (14) being arranged on the other side of the fingers (13) substantially halfway between the two other pinions (14).

4. System according to claim 3, characterized in that each pinion (14) is driven by a motor means (18) with two directions of rotation, and in that means (46) are provided for detecting resistance to advancement of the carriage (2) exceeding a predetermined threshold and to reverse in this case the direction of rotation of said motor means (18).

5. System according to claim 4, characterized in that each motor means (18) is a geared motor (18) with electronically controlled alternating output supplied with low voltage direct current, the three geared motors being supplied in parallel from an electrical cabinet (46 ), each geared motor (18) being equipped with a revolution counter device.

6. System according to any one of claims 1 to 5, characterized in that the carriage (2) comprises a central body (19) carrying the (or) pinion (s) motor (s) (14), and in that said central body (19) is slidably mounted on at least one longitudinal slide (20) carried at each of its longitudinal ends (21, 22) by a support member (23) mounted on wheels (24).

7. System according to claim 6 and claim 3, characterized in that each support member (23) comprises two wheels (24) adapted to roll on the guide rail (7) on either side of the row (12 ) of fingers (13).

8. System according to claim 6 or 7, characterized in that each support member (23) comprises means (31, 32) for bearing transversely on one or the other of the lateral faces (25, 26) of the rail guide (7).

9. System according to one of claims 6 to 8, characterized in that each support member (23) has its end opposite to the central body (19) of tapered shape in plan view and in profile view.

10. System according to one of claims 6 to

9, characterized in that at least one compression spring (33) is mounted between the central body (19) and each of the support members (23).

11. System according to one of claims 1 to 10, characterized in that the transverse tube (4) of suction is pivotally mounted on the carriage (2).