JPS6242645B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a sewage sludge dewatering device, and in particular,
The present invention relates to a device that sucks moisture in sewage sludge through a screening belt and dewaters the sludge.

Traditional methods of naturally dewatering sludge in sludge drying beds have been made impossible due to lack of space and labor. Therefore, it is necessary to artificially dehydrate the sludge to the point where it can be scooped up with a hoe and to make it easier to transport.

Various devices have been proposed to achieve this purpose. For example, after using a relatively large amount of coagulation accelerator, a considerable amount of negative pressure is applied from below the screening belt to the sludge sludge spread on the endless screening belt, and the sludge is dewatered by suction. It has been known.

However, in conventional devices of this kind, a large amount of liquid dehydrated from sludge flows into the suction pipe itself that supplies negative pressure, making it difficult to supply sufficient negative pressure.

The present invention has been made in view of the above points,
The purpose is to provide a sludge dewatering device that can reliably dewater sludge.

That is, the sludge dewatering apparatus of the present invention includes an endless screening belt that continuously transports sludge lumps from a passing zone to a suction zone to a squeezing zone, and an endless screening belt that continuously transports sludge lumps from a passing zone to a suction zone to a squeezing zone, and an endless screening belt that sucks water passed through the screening belt. A suction chamber provided in the suction zone and transverse to the direction of travel of the endless screening belt to distribute the conveyed sludge onto the endless screening belt with a substantially uniform thickness; sludge dispersion means disposed near the boundary between the zone and the suction zone;
The endless screening belt comprises a turning means provided in the squeezing zone to turn the endless screening belt, and a squeezing belt provided to press the sludge pre-dried in the suction zone onto the turning means. The squeezing belt is in contact with the sludge at a loop angle smaller than a loop angle with respect to the diverting means.

Another feature of the invention comprises the step of artificially dewatering sewage sludge by using an endless screening belt and spreading the sludge on said screening belt, with or without the addition of a coagulation accelerator; Its features include a sludge spread out on the screening belt, an overflow zone, a slightly low-pressure suction zone,
Finally, it passes continuously through the squeezing zone. By combining dehydration with filtration, suction, and compression, a high dehydration effect can be obtained at low cost.

Hereinafter, preferred specific examples of the present invention will be explained based on the drawings. The plant as a sludge dewatering device consists of three successive zones: a filtration zone 10, a suction zone 12 and a squeezing zone 14. Sewage sludge 16 is introduced via a stirring device 62 . The stirring device 62 is equipped with a stirring screw drive mechanism and mixes the introduced sludge 16 with a coagulation accelerator 68. It is noteworthy that the amount of coagulation accelerator required in this new plant is significantly less than that required in the conventional plant. Sludge 16 mixed with coagulation accelerator 68 in filtration zone 10
from the stirring device 62 to the endless screening belt 1
8. In this zone, the screening belt 18 is arranged with a slight upward slope in the direction of travel.

Dispersion device or roller 32 as sludge dispersion means
functions to distribute the sewage sludge onto the screening belt 18 with uniform width and thickness. Due to this equalizing effect, at the same time the screening belt 18 is coated with an even layer of sludge before reaching the suction zone 12. A dispersing device or roller 32 is transverse to the direction of travel of the screening belt 18;
It may also be a coating knife 34 arranged at a constant distance from the belt 18. The applicator knife is arranged perpendicularly to the surface of the screening belt 18 according to FIG. 1b. However, it may also be arranged as in FIG. 1c, in which case the deformation distribution means 36 are inclined in the direction of travel of the screening belt 18. 1a instead of dispersion knife
It is also possible to use rollers 32 as shown. The rollers 32, which are likewise arranged at an adjustable spacing relative to the screening belt, may be of the free-rotating type or may be provided with a drive mechanism that rotates the rollers 32 in the direction of travel or opposite the screening belt 18. May be connected. Said rollers disperse and spread the sludge 16 more completely onto the screening belt 18. Either type of dispersion device is placed proximate the forward end of the overzone 10.

In the pass zone, the screening belt 18 functions as a cloth. That is, a portion of the moisture content of the sludge 16 falls freely through the screening belt 18 solely due to its own gravity.

Actuation takes place without applying pressure. That is, there is no suction from below the screening belt 18, and no pressure is exerted on the sludge except for the pressure exerted by the dispersion device or rolls 32. However, the pressure applied by the dispersion device is very small. Falling moisture is collected in tank 76 and then drained into sump 56 via pipe 78a.

A tension roll 80 of the screening belt 18 is mounted within the passing zone 10 . The suction zone 12 is directly connected to the rear of the pass zone 10 in the direction of travel. Suction zone 12
consists essentially of a suction chamber 26 which is completely closed. A permeable support member 22 is mounted on top of the suction chamber 26 over which a screening belt 18 slides to transport the sludge cake 16 spread onto the screening belt 18. The support member 22 may be a grid plate or a perforated plate or any other suitable flat transparent plate-like member with openings 24 of some shape. The sludge cake 16 has an opening 24
The chamber 26 and the passage of the screening belt 18 are sealed from above. Elastic seals mounted on the side frames on both sides reliably function as side guides and seals.

In order to establish a slight low pressure, for example, about 500 to 2000 mmAq, the chamber 26 is connected to the suction pipe 5.
4. A side opening 52 is provided. Opening 5
2 is arranged on the side of the chamber 26 at a considerable distance from the holding tank 42 arranged below, so that there is no risk of the aspirated fluid flowing into the suction opening 52. The fluid may be collected within the tank. The pipe 54 is connected to a collection pipe 85, which leads to a discharge trap 84. The entrained moisture is captured in the drain trap 84 and conveyed to the sump 56 via the pipe 86. A vacuum pump 88 as suction means, schematically illustrated, serves to establish a low pressure and is connected via a pipe 87. By configuring the suction means in this way, negative pressure can be supplied more reliably,
This is preferable because the sludge can be reliably dehydrated by suction.

The water sucked into the chamber 26 from the sludge 16 and collected in the holding tank 42 flows in an inclined direction and flows into the pipe 42 from the outlet 40. Said pipe 4
3 extends to the lowest part of the water surface of the drainage basin 56, and since low pressure prevails inside the chamber 26, the pipe 4 is formed as a pipe made of a transparent material, for example.
The liquid is constantly rising in a part of 3. The degree of this increase can then be used as a measure of the underpressure present within chamber 26.

Details of the squeezing zone 14 connected to the rear of the suction zone 12 are shown in the left-hand part of FIG. 1a. In the squeezing zone 14 the screening belt 18 rotates along a relatively large diameter impermeable drive roller 20 .

The sludge 16 pre-dried in the filtration zone 10 and the suction zone 12 is squeezed by a squeezing belt 30 that is conveyed in the advancing direction from the introduction part of the squeezing zone 14 via a tension roller 28a. The squeezing belt 30 is transparent and is driven along the screening belt 18 via a total of three rollers 28 in this example. In this specific example,
A central drum controller roller 28b is fixedly arranged, and the axis of the tension roll or roller 28b can be formed as a support and pivot axis for the tension roll 28a. For this purpose, the axis of the tension roll 28b carries a length-adjustable extension rod 94, so that the length can be adjusted, for example, by means of two opposing screws and a threaded sleeve surrounding these screws. can be adjusted.
In this way, the distance between the axes of the rollers 28b and 28a is adjusted, and thereby also the tension of the squeezing belt 30, which adjustment causes the pressure exerted on the drive roller 20 as deflection means and thus on the screening belt. The pressure applied to the screening belt 18 and the pressing belt 3 is adjusted.
The pressure applied to the sludge cake 16 can be adjusted between 0 and 0. Additionally, a tension roll or roller 28a
The axis may be loosely fixed at an adjustable angle from the parallel line of the screening belt 18 in the direction of the arrow, so that the sludge cake 16 is progressively and gradually fed into the squeezing process.

The squeezing takes place between the screening belt 18 and the squeezing belt 30 in the area of the drive roller 20. Since the drive roller 20 is impermeable,
The water remaining in the sludge cake 16 is removed by the squeezing belt 3
0 and is collected in a holding tank 90 and pipe 91
The water is discharged to a drainage basin 56 via the water tank.

Although not required, a slotted suction port 60 may be provided and connected to the suction collection pipe 85 to assist in this process. Said pipe is guided from the back into the area of the drive roller 20 and faces the squeeze belt 30 . Moisture sucked in by the suction port 60 is captured by a simple conventional device not shown here and then transported to a holding tank 90.

In many cases, the sludge cake 16 is
A paper bund 74 of sludge material is formed which can be easily transported via a conveyor belt 75 and later removed from the plant in a suitable manner.

As is clear from the figure, the loop angle of the squeezing belt 30 around the drive roller 20 is smaller than the loop angle of the screening belt 18 around the same drive roller. The papery bundle 74 of sludge material therefore easily separates from the two belts.

Compression belt 3 on its way back inside the compression zone 14
0 or the squeezing belt between rollers 28c and 28b can be cleaned of adhering sludge particles by a suitable cleaning device 73. In this case, the sludge, which has been gradually dewatered in stages, has no tendency to enter and adhere to the openings of the press belt 30 and the screening belt 18, and therefore cleaning for the purpose of complete cleaning of the press belt is not necessary. It should be pointed out that the amount of water required for the process is very small and that only occasional washing steps are required.

The cleaning of the screening belt 18 on its way back can also be carried out in a simple manner by means of a freshwater utilization device 77 arranged between the drive roller 20 and a further drum controller 79. The wash water is collected in a small tank and conveyed via pipe 91 to sump 56.

The water required for the cleaning process is distributed via pipes 50. Also, a relatively clean liquid may be used.

Finally, the screening belt 18 that has passed the drum controller 79 is directed to the primary tension roller 80, after which the screening belt 18 begins the new circulation necessary for continuous operation.

Incidentally, the suction may be formed in multiple stages, and the low pressure may be gradually increased in each stage in the sludge transport direction. Due to the multi-stage configuration of the suction zone, a high degree of plasticization is achieved in the final suction stage despite the initial careful suction, resulting in a smooth transfer of the sludge cake to the squeezing zone.

FIG. 2 is an overall view showing another specific example of the present invention. In this example, the same reference numerals as in FIGS. 1a, 1b, and 1c are the same members as in the previous example and function in the same way, so a detailed explanation thereof will be omitted.

The sludge 16 pre-dried by the filtration zone 10 and the suction zone 12 is led to the squeezing zone 14. A pressing belt 30 is placed on top of this sludge. This squeeze belt runs in the conveying direction at the entrance to the squeeze zone 14 before the tension roller 28. The squeezing belt 30 is transparent and in this embodiment is guided over all three rollers 28 , 29 , 39 and driven by the screening belt 18 . In this embodiment, the intermediate steering roller 29 is stationary, and the axis of the tension roller 28 may be formed as a support and pivot axis for the roller 29. The axial distance between the rollers 28 and 29 is freely adjustable, thereby making it possible to adjust the tension of the pressing belt 30. And through the adjustment of this tension, the sludge mass 16 between the screening belt 18 and the squeeze belt 30 is simultaneously applied to the drive roller 20.
The pressing force against can also be adjusted freely. Furthermore, the axis of the tension roller 28 can be fixed in a position slightly angled from the parallel of the screening belt 18 in the direction of the arrow. This is sludge mass 1
This is to compress 6 slowly little by little. Such a configuration is the same as the specific example described above.

In the squeezing zone 14, paper-like bands or crushed sludge material are produced from the sludge mass 16. This can be easily carried away via the screening belt 82 and conveyed in a suitable manner to the zigzag zone 15 formed as the fourth drainage zone.

The zigzag zone 15 consists of a number of rollers 78 whose axes are aligned with the screening belt 1.
The screening belts 18 and 82 are mounted horizontally across the conveying direction of the belts 8 and 82 and horizontally to the screening belts 18 and 82. The rollers 78 are horizontal in the conveying direction;
Screening belt 1 guided between rollers
8, 82 are mounted longitudinally with respect to each other so that they run in an undulating manner during operation. The screening belt 82 is guided around a deflection roller 84 before and after the zigzag zone. This screening belt 82 is also formed as an endless belt.

After the sludge mass passes through the squeezing zone 14 and falls onto the screening belt 82, the sludge mass is conveyed between the two screening belts 18 and 82, and then conveyed between the guide rollers 78 in a wave-like motion. Ru. At this time, the sludge mass is sufficiently compressed and sheared by compressive stress and shear stress. This results in a further considerable drainage of the sludge mass.
It is also possible to run screening belts at different speeds to increase this crushing effect. It is also possible to set a part of zone 15 to a negative pressure state. The water removed in the zigzag zone 15 directly flows into the receiving water tank 76. Since this receiving water tank is an integrated component of the entire device, the entire device enclosed by the casing 86 can be installed as a tight structural unit anywhere in any desired location. After passing through the zigzag zone 15, the sludge mass 16 floats up from the turning roller 84 and transfers to the conveying belt 8.
8. The drained sludge mass is carried away in a very good manner by means of this conveying belt.

Because the degree of shear stress is adjustable, the guide rollers 78, particularly the upper rollers, are mounted movably transversely to the conveying direction. In particular, the zigzag zone may be divided into two separate steps. In this case, the longitudinal offset of the roller in the first step is smaller than in the second step. This results in greater shear stress in the second step than in the first step. The rollers may overlap directly at the ends of each step. As a result, the sludge mass is compressed again by compressive stress due to the shear stress.

Finally, the screening belt 18 is guided to a tension roller 80 behind which the screening belt 18 begins its circulation anew. This circulation is necessary for continuous operation.

Incidentally, in order to make the overall structural dimensions of the sludge dewatering device as short as possible even with the addition of the fourth drainage zone, it is possible to install the fourth drainage zone below the suction zone.

As described above, in the present invention, the pre-dried sludge conveyed from the suction zone by the endless screening belt is compressed by the pressing belt on the drive roller of the pressing zone, so that the sludge becomes a paper-like sludge cake and is screened endlessly. detach from the belt. In this case, the loop angle of the squeezing belt around the drive roller is smaller than the loop angle of the endless screening belt around the same drive roller, so that the paper band of sludge can be easily separated from the two belts.

Some examples of embodiments of the invention are listed below.

3. Device according to claim 1, characterized in that: (1) the squeezing zone is arranged in the area of the guide roller of the screening belt;

(2) The screening belt passing through the passing zone passes through the cloth-shaped passing zone very freely;
Claim 1, characterized in that in the suction zone it moves over a suction chamber covered by a support member and in the squeeze zone is subjected to the pressure of an endless squeeze belt guided by at least two rollers.
2 and the device according to any of the preceding paragraphs.

(3) Apparatus according to any one of the preceding claims, characterized in that in the squeezing zone the screening belt is guided over an impermeable surface.

(4) Claim 1 or 2 characterized in that in the overflow zone dewatering is carried out without negative pressure, and in the subsequent suction zone it is carried out with a slightly lower pressure.
The device described in.

(5) The apparatus according to any one of claims 1 and 2 and each of the above items, characterized in that the final stage of the compression zone runs in the vertical direction.

(6) The apparatus according to any one of claims 1 and 2 and each of the above items, characterized in that the compression belt separated from the screening belt moves straight ahead by a certain distance.

(7) A fourth drainage zone is provided behind the pressing zone, and in the fourth drainage zone, shear stress is applied to the sludge mass formed in the pressing zone. 2. The device according to 2.

(8) The device according to item (7) above, wherein the sludge mass is compressed within the fourth drainage zone as a certain shear stress progresses.

(9) The device according to any one of (7) and (8) above, characterized in that the sludge mass is transported by performing wave-like motion in the transport direction.

(10) The device according to claim 1 or 2, wherein the screening belt is arranged with a slight upward slope in the traveling direction in the passing zone.

(11) The device according to claim 1 or 2, wherein the dispersion knife is arranged at a distance from the screening belt.

(12) The device according to item (11) above, wherein the dispersion knife is arranged perpendicularly to the surface of the screening belt.

(13) The device according to item (12) above, wherein the dispersion knife is inclined in the advancing direction of the screening belt.

(14) The apparatus according to claim 1 or 2, wherein the roller is arranged at a distance from the screening belt.

(15) The device according to item (14) above, wherein the roller is of a freely rotating type.

(16) The device according to item (14), wherein the roller can be driven in a direction opposite to the traveling direction of the screening belt.

(17) The device according to item (14) above, wherein the roller can be driven in the same direction as the screening belt.

(18) The device according to claim 1 or 2, wherein the suction means includes a suction pump, and a connecting line of the pump opens into the suction chamber from the side above the holding tank.

(19) The device according to claim 1 or 2 or the preceding paragraph (18), characterized in that the suction chamber is subdivided into several chambers having a lower pressure increasing in the direction of travel of the screening belt. .

(20) A patent characterized in that the suction chamber communicates with a water tank via a conduit, said conduit being immersed in said tank and thereby being formed as a pressure measuring device in the suction chamber. The device according to claim 1 or 2 or the preceding item (18).

(21) Device according to any one of the preceding claims, characterized in that the impermeable surface is the surface area of the drive roller for the screening belt of the squeezing zone.

(22) The device according to item (21), wherein the pressing belt pushes out a screening belt that is conveyed by a drive roller.

(23) The apparatus according to any one of claims 1 and 2 and the preceding clause, characterized in that the squeezing belt is not equipped with a self-driving mechanism and can be moved by a screening belt.

(24) The apparatus according to any one of claims 1 and 2 and the preceding clause, wherein the pressure in the compression zone is adjustable by changing the tension of the compression belt.

(25) The apparatus according to any one of claims 1 and 2 and the preceding clause, characterized in that the opening angle of the pressing belt with respect to the screening belt is adjustable.

(26) The device according to claim 1 or 2, the preceding item (24) or the preceding item (25), characterized in that a device is formed to freely adjust the tension or opening angle of the compression belt.

(27) The residual water squeezed out from the squeezing belt is 1
3. A device according to claim 1, characterized in that the device is suctioned by one or several suction devices.

(28) Apparatus according to any one of claims 1 and 2 or the preceding clause, characterized in that the squeezing belt is spaced from the drive roller according to a smaller loop angle than the screening belt.

(29) The device according to the preceding item (28), characterized in that the squeezing belt separated from the screening belt is conveyed a short distance in a tangential direction.

(30) The device according to the preceding item (28), characterized in that the loop angle is adjustable.

31. Device according to claim 1, 2 or any of the preceding claims, characterized in that the final guide roller of the squeezing belt has a diameter essentially smaller than the drive roller of the screening belt.

(32) The device according to claim 1 or 2, having the following characteristics.

(a) An endless screening belt is conveyed freely in the pass zone as a cloth, moves in the suction zone over a suction chamber covered by a support member, and in the squeeze zone is an endless squeezing belt supported by at least two rollers. under pressure; (aa) dewatering in the overzone is carried out without the use of low pressure; (ab) the screening belt in the overzone is arranged at a slight upward slope in the direction of travel; (ac) in the overzone. a device arranged transversely to the direction of travel of the screening belt spreads and distributes the sewage sludge onto the screening belt in a uniform thickness and width; (ad) said device is arranged perpendicularly or obliquely to the surface of the screening belt; (ae) said device is a roller arranged at a distance from the screening belt and freely rotating in the direction of travel of the screening belt or in the opposite direction; (bb) suction; (bc) The suction chamber consists of a closed chamber with a holding tank inclined towards the outlet and a supporting member arranged above, through which the water is removed by a screening belt. side seals are provided for the sewage sludge to be conveyed, and the suction chamber furthermore has a low pressure device connected to the suction device; (bd) the suction chamber is subdivided into several chambers, the suction chamber being subdivided into several chambers; The low pressure increases in the direction of travel of the screening belt, (be) the suction device is equipped with a suction pump, the connecting line of which opens into the interior of the suction chamber from the upper side of the holding tank, ( bf) the suction chamber communicates with the sump via a pipe, said pipe immersing into said sump and being formed as a pressure measuring pipe in the suction chamber; (cc) the squeezing zone is connected to the guide of the screening belt; (cd) the squeezing zone screening belt is guided to an impermeable surface; (ce) the impermeable surface is the surface area of the roller driving the squeezing zone screening belt; (cf) The squeeze belt may press against a screening belt conveyed by a drive roller.
(cg) The pressure in the squeezing zone is controlled by means of a device which is movable by the screening belt without any self-driving mechanism and is constructed so that the tension of the squeezing belt and the opening angle of the screening belt can be varied at will. (ch) the residual water squeezed out of the pressing belt is sucked off by one or several suction means; (ci) the final stage of the pressing zone is separated from the vertically running screening belt; the squeeze belt is guided tangentially by a short distance; (cj) the squeeze belt is spaced from the drive roller according to an adjustable loop angle that is smaller than the loop angle of the screening belt; (ck) the final guide roller of the squeeze belt; (33) having an essentially smaller diameter than the drive roller of the belt, characterized in that in the fourth drainage zone an additional screening belt is guided between the rollers around the screening belt and at least one end roller; The device described in the preceding paragraph (7), (8) or (9).

(34) The device according to the preceding item (30), characterized in that the upper roller and/or the lower roller are movable in a direction above adjacent rollers across the conveying direction.

(35) The device according to any one of (33) and (34) above, wherein at least two rollers are movable.

(36) The device according to item (35) above, characterized in that the rollers are mounted so as to press against each other at the ends of each roller block.

(37) The device according to any one of claims 1 and 2 and the preceding items (33) to (36), wherein the fourth drainage zone is installed below the suction zone.

(38) The device according to claims 1 and 2 and any one of the preceding items (33) to (37), characterized in that the integrated receiving water tank accommodates the water removed in all four drainage zones.

(39) The device according to the preceding item (38), characterized in that the water removed in the fourth drainage zone flows directly, and the water removed in the filtration and suction zones flows into the receiving water tank via a conduit.

(40) The device according to the preceding item (38), wherein the drain port of the receiving tank is installed at a high position so that a constant water level is maintained in the tank.

(41) characterized in that the conduit conveying the water removed in the suction zone extends into the water of the receiving tank, and the conduit guiding the water removed in the suction zone leads above the water level of the receiving tank. The device according to any one of the preceding paragraphs (33) to (40).

(42) Claims 1 and 2 and the preceding paragraphs (33) to 33 are characterized in that the entire device is formed as a unit that is transportable and can be installed anywhere, and a receiving water tank is incorporated therein. The device described in any of (41).

[Brief explanation of the drawing]

Figure 1a is a schematic explanatory diagram of the device of the present invention, Figure 1b,
FIG. 1c is an explanatory view showing a detailed modification of the passing zone, and FIG. 2 is a schematic explanatory view of an apparatus of the present invention having a different configuration from the apparatus of FIG. 1a. 10... Excess zone, 12... Suction zone, 1
4... Squeezing zone, 16... Sludge, sludge cake,
18... Screening belt, 20... Roller, 22... Support member, 24... Opening, 26...
... Suction chamber, 28 ... Roller, 30 ... Pressing belt, 32 ... Roller, 34 ... Application knife,
36... Dispersion means, 40... Outlet, 42... Tank, 52... Opening, 56... Drainage basin, 60...
... Port, 62 ... Stirring device, 68 ... Coagulation accelerator, 73 ... Washing device, 74 ... Paper bread, 7
5... Conveyor belt, 76... Tank, 77...
...Freshwater utilization device, 79...Drum controller,
80...Tension roller, 84...Trap,
88...vacuum pump, 90...tank, 94...
Rod.

Claims (1)

[Claims] 1. An endless screening belt that continuously conveys the sludge mass from the filtration zone to the squeezing zone via the suction zone, and a suction chamber provided in the suction zone to suction the moisture passed through the screening belt. , in order to disperse the conveyed sludge onto the endless screening belt with a substantially uniform thickness, the belt is transverse to the traveling direction of the endless screening belt, and is located near the boundary between the passing zone and the suction zone. sludge dispersion means arranged in the squeezing zone for deflecting the endless screening belt; and a squeezing means arranged in the squeezing zone for forcing the sludge pre-dried in the suction zone onto the diverting means. Apparatus comprising a belt, characterized in that the squeezing belt is in contact with the sludge at a loop angle smaller than the loop angle of the endless screening belt relative to the diverting means.