JPS621420A - Apparatus for dehydrating sludge - Google Patents

Abstract

PURPOSE:To surely perform the dehydration of sludge, by increasing pressures in partial chambers formed by finely dividing a suction chamber toward the advance direction of an endless screening belt. CONSTITUTION:The titled apparatus is constituted of a filter zone 10, a suction zone 12 and a pressure zone 14. The suction zone 12 essentially comprises a perfectly closed suction chamber 26 while the suction chamber 26 is finely divided into several chambers and the pressures in the finely divided chambers are increased toward the advance direction of an endless screening belt 18. Therefore, even if a suction vacuum degree is lowed with respect to sludge with high moisture content, a considerable amount of water can be removed and the dehydration of sludge with reduced moisture content can be performed in a relatively averaged amount and, therefore, the dehydration of sludge can be surely performed.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus for dewatering sewage sludge, and particularly to an apparatus for dewatering sludge by sucking water in sewage sludge through a screening belt.

Traditional methods of naturally dewatering sludge in sludge drying beds have been precluded by a 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,
BACKGROUND ART A device is known that applies considerable negative pressure to sludge spread on an endless screening belt from below the screening belt, thereby dewatering the sludge by suction.

However, in conventional devices of this type, P liquid dehydrated from sludge flows multiple times 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, and an object thereof is to provide a sludge dewatering device that can reliably dewater sludge.

That is, the sludge dewatering apparatus of the present invention is a sludge dewatering 5A system in which sludge is continuously conveyed from a filtration zone to a suction zone by an endless screening belt, and a portion of water is removed in the 1' passing zone. The suction chamber includes a suction chamber provided in the suction zone to suction moisture from the filtered sludge through the endless screening belt, and suction means for generating a low pressure in the suction chamber. ! It is characterized in that the lower pressure in each partial chamber increases in the direction of travel of the endless screening belt.

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 feature is that the sludge spread on the screening belt passes continuously through a filtration zone, a slightly low-pressure suction zone, and finally a squeezing zone.

By combining dehydration of T' 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 consecutive zones: a beating zone 10, a suction zone 12 and a squeezing zone 14. Sewage sludge 16 is mixed through a stirring device 62. The stirring device 62 is equipped with a stirring screw drive mechanism, and the introduced sludge 16 is mixed with a coagulation accelerator 68.
Mix with. It is noteworthy that the amount of coagulation accelerator required in this new plant is significantly less than that required in the conventional plant. Filtration zone 10
The sludge 16 mixed with the coagulation accelerator 68 is dispersed onto the endless screening belt 18 from the stirring device 62.

In this zone, the screening belt 18 is arranged with a slight upward slope in the direction of travel.

The dispersing device beating roller 32 is connected to the screening belt 18
It functions to distribute sewage sludge on top in an even 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. The dispersing device or roller 32 may be an applicator knife 34 disposed transversely to the direction of travel of the screening belt 18 and spaced apart 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 shown in FIG. Instead of a dispersing knife, it is also possible to use a roller 32 as shown in FIG. 1a. Similarly, the roller 32, which is arranged at an adjustable distance with respect to the screening belt, may be of a free rotation type, or a drive 111J mechanism that rotates the row 532 in the advancing direction of the screening belt 18 or in the opposite direction. may be connected to 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 filtration zone 10.

In the filtration zone, the screening belt 18 functions as a P 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 roll 32. However, the pressure applied by the dispersion device is very small.

Falling moisture is collected in a tank 76 and then drained into a sump 56 as an r-receiving tank via a pipe 78a.

A screening belt 18 is placed within the P'A zone 10.
A tension roll 80 is attached. The suction zone 12 is directly connected to the rear of the filtration zone 10 in the direction of travel. The suction zone 12 essentially consists of a completely closed suction chamber 26. 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. Is the support member 22 a lattice plate, a perforated plate, or some other shape of opening? ! 24 may be any other suitable flat transparent plate-like member. The sludge cake 16 seals the chamber 26 and the passage of the screening belt 18 from above the opening PIS 24 . Elastic seals mounted on the side frames on both sides reliably function as side guides and seals.

The chamber 26 is provided with a side opening 52 connected to a suction pipe 54 in order to establish a slight low pressure, for example of the order of 500 to 2000 Kakuhachi. The opening 52 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 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 drain trap 84 and conveyed to sump 56 via via 86 . A vacuum pump 88 as a suction means, schematically illustrated, serves to establish a low pressure and a pipe 87
connected via. It is preferable to configure the suction means in this way because negative pressure can be supplied more reliably and 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 43 from the outlet 40. The pipe 43 extends to the lowest part of the water surface of the drainage basin 56, and low pressure prevails in the chamber 26, so that the P liquid always rises to a part of the pipe 43, which is formed as a pipe made of a transparent material, for example. ing. 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. 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, ie, a 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 embodiment, the central drum control roller 28b is fixedly arranged, and the tension roll or roller 28b is fixedly arranged.
The axis of can be formed as a support and pivot axis of 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 the tension of the compression belt 30 is also adjusted.
By adjusting the tension, the pressure applied to the drive roller 20 and therefore the screening belt 18 can be adjusted, and the pressure applied to the sludge cake 16 between the screening belt 18 and the squeeze belt 30 can be adjusted. Furthermore, the axis of the tensicon roll or roller 28a may be loosely fixed in a position at an adjustable angle from the parallel line of the screening belt 18 in the direction of the arrow, so that the sludge cake 1G is gradually and gradually removed. It is sent to the pressing process.

The squeezing takes place between the screening belt 18 and the squeezing belt 30 in the area of the drive IO-ra 20. Since the drive roller 20 is impermeable, the water remaining in the sludge cake 16 passes through the squeezing belt 30 and is collected in the holding tank 90 and discharged via the pipe 91 to the sump 56.

Although not necessary, a slotted suction boat 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 . The water sucked in by the suction boat 60 is captured by a simple conventional device not shown here and then discharged to a holding tank 90.

In many cases, a paper band 74 of sludge material is formed from the sludge cake 16 in the squeezing zone 14, 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.

Therefore, the paper-like band γ4 of sludge material easily separates from the two belts.

The squeezing belt 30 on its way back inside the squeezing zone 14, ie the squeezing belt between the rollers 28C and 28b, can be cleaned of adhering sludge particles by a suitable cleaning device 73.

In this case, the sludge that has been gradually dewatered in stages has no tendency to enter and adhere to the openings of the press belt 30 and the openings of the screening belt 18, and therefore the cleaning step aims at complete cleaning of the press belt. It should be pointed out that the amount of water required for this process is very small, and that cleaning steps only need to be carried out occasionally.

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.

Alternatively, relatively clean P liquid may be used.

Finally, the screening belt 18 that has passed the drum controller 19 is guided to the primary tension roller 8o, after which the screening belt 18 has passed the tension roller and begins a 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 FIG. 1a, FIG. 11O, and FIG. 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 squeeze belt 30 is transparent;
In this example, it is guided through all three rollers 28, 29, 39 and driven by the screening belt 18. In this specific example, the intermediate steering roller 29 is in a fixed state, and the axis of the tension control roller 28 is
It may also be configured as a support and pivot for the 9. low 5
The axial distance between 28 and 29 is adjustable, and thereby the tension of the compression belt 30 can be adjusted. And through this adjustment of the tension, the sludge mass 1 between the screening belt 18 and the pressing belt 30 is simultaneously applied to the drive roller 20.
The pressing force against 6 can also be adjusted freely. Furthermore, the axis of the tension control roller 28 can be fixed in a position slightly angled from the parallel line of the screening belt 18 in the direction of the arrow. This is to slowly compress the sludge mass 16 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 γ8 whose axes are transverse to the direction of conveyance of the screening belt 18.82 and are mounted horizontally to it. The rollers 78 are horizontal in the transport direction and are mounted longitudinally with respect to one another so that the screening belts 18.82 guided between the rollers run in an undulating manner during operation. The screening belt 82 rotates the front of the zigzag zone by a turning roller 84.
are being guided around. 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 jig deg 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 jigdig zone 15 , the sludge mass 16 is lifted up from the deflection rollers 84 and placed on a conveyor belt 88 . The drained sludge mass is carried away in a very good manner by means of this conveying belt.

Since the degree of shear stress is adjustable, guides 0-5
78, in particular the upper roller is mounted so as to be movable transverse to the transport direction. In particular, the zigzag zone may be divided into two separate steps.

In this case, the longitudinal offset of the rollers 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 end rollers of each process may be directly molded.

As a result, the sludge mass is compressed again by compressive stress based on the shear stress.

The most sensitive part of the screening belt 18 is the tension roller 8.
0, and behind this roller 80 the screening belt 18 begins a new circulation. 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 suction chamber is subdivided into several chambers, and the low pressure in each subchamber is configured to increase in the direction of movement of the endless screening belt. For sludge with a lot of water content, even if the degree of suction vacuum is low, it is possible to remove water from the north. On the other hand, dewatering sludge with a low water content is difficult at the same degree of vacuum as for sludge containing a large amount of water. Therefore, by passing through several suction chambers whose degree of vacuum increases in the direction of travel of the endless screening belt, relatively even dehydration can be achieved. If the distance of the suction zone through which the endless screening belt passes is the same, the dewatering efficiency can be increased by passing through several chambers whose degree of vacuum increases in the belt conveyance direction.

Some examples of embodiments of the invention are listed below.

1. 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 filtration zone is P
passing very freely through a filtration zone in the form of a cloth and moving in a suction zone over a suction chamber covered by a support member;
Device according to any one of the preceding claims, characterized in that it is subjected to the pressure of an endless press belt guided by at least two rollers in the pressure path zone.

(3) The screening belt is guided over an impermeable surface in the squeezing zone (
1), (2), and the device according to any one of the above items.

(4) The dewatering process according to claim 1 or 2 is characterized in that in the F' passage zone dehydration is carried out without negative pressure, and in the subsequent suction zone it is carried out at a slightly lower pressure. Device.

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

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

(8), the previous item (7) characterized in that the sludge mass is compressed in accordance with the progress of a certain shear stress within the fourth drainage zone.
).

(9) The apparatus according to any one of (7) and (8) above, wherein 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 at a slight upward slope in the direction of travel in the filtration zone.

(11) The device according to claim 1 or 2, characterized in that the dispersing knife is arranged at a distance C from the screening belt.

(12), the previous section (1
1).

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

(14), Claim characterized in that the roller is arranged at a distance from the screening belt (
The device according to 1) or (2).

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

(16), the preceding clause (14), characterized in that the roller can be driven in a direction opposite to the advancing direction of the screening belt;
The device described in.

(17) The apparatus according to item (14), characterized in that the roller can be driven in the same direction as the screening belt.

(18) The suction means is equipped with a suction pump, and the connecting pipe line of the pump is connected to the suction pipe 11 from the side above the holding tank.
Claim (1) characterized in that the invention opens to the chamber.
Or the device described in (2).

(19), Claim (1) characterized in that the suction chamber is subdivided into several chambers with a low pressure that applies debris in the direction of travel of the screening belt.
, (2) or the device described in the preceding section (18).

(20), characterized in that the suction chamber communicates with a water tank via a conduit, and the conduit is immersed in the tank, thereby forming a pressure measuring device in the suction chamber. The device according to claim (1), (2) or the preceding clause (18).

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

(22) The device according to the preceding item (21), wherein the ff feature is that the pressing belt presses the screening belt conveyed by the drive roller.

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

(24) The device according to any one of claims 11 and (2) and the preceding paragraph, characterized in that the pressure in the compression zone can be adjusted by changing the tension of the compression belt.

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

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

(27) The device according to any one of claims (1) and (2) and the preceding paragraph, characterized in that the residual water squeezed out of the squeezing belt is sucked by one or several suction devices. .

(28) A device according to any of the preceding claims, characterized in that the squeezing belt is spaced from the drive roller according to a smaller loop angle than the screening belt.

The device according to the preceding paragraph (28) as a sign.

(30) The device according to item (28), wherein the loop angle is adjustable.

(31) The device according to claim 1, (2) or any of the preceding paragraphs, 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 features.

(a) The endless screening belt is freely conveyed through the filtration zone as a P cloth, coated on the support member in the suction zone, and 1. (aa) Dewatering in the filtration zone takes place without the use of low pressure; (ab) in the filtration zone; The screening belt is arranged at a slight upward slope in the direction of travel. (ac) In the filtration zone, a device arranged transversely to the direction of travel of the screening belt spreads the sewage sludge onto the screening belt in an even thickness. (ad) said device is a dispersing means arranged perpendicularly or obliquely to the surface of the screening belt; (aC) said device is arranged at a distance from the screening belt; (bb) The dewatering of the suction zone is carried out at a slightly lower pressure (
b) The suction chamber consists of a closed chamber with a holding tank inclined towards the outlet and a supporting member arranged above, provided with side seals for the sewage sludge conveyed by the screening belt via the supporting member. (bd) the suction chamber is subdivided into several chambers, the low pressure in each subchamber increasing in the direction of travel of the screening belt; (be) the suction means is equipped with a suction pump, the connecting pipe line of which opens into the suction chamber from the upper side of the holding tank; (M) suction chill! the chamber communicates with the receiving tank via a pipe, said pipe immersing into said receiving tank and being formed as a pressure measuring pipe in the suction chamber. (cd) the screening belt of the squeezing zone is guided to an impermeable surface; (ce) the impermeable surface is the surface area of the roller driving the screening belt of the squeezing zone; (cf) The squeezing belt may press against a screening belt that is conveyed by a drive roller. In addition, the pressure in the compression zone is increased 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 (CCI) compression belt and the opening angle of the screening belt can be varied at will. (ch) the residual moisture squeezed out of the squeezing belt is sucked by one or several suction means; (ci) it is separated from the vertically running screening belt at the final stage of the squeezing zone; (cj) the squeezing 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 squeezing belt is guided tangentially by a short distance; (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 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)'%, characterized in that at least two of the rollers are movable.

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

(31) Claim (1) characterized in that the fourth drainage zone is installed below the suction zone.

(2) and the device according to any one of the preceding sections (33) to (36).

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

(39), the water removed in the fourth drainage zone is directly
The water removed in the F' filtration and suction zone flows into the receiving water tank via the conduit (38).
).

(40) The device according to 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) The conduit carrying the water removed in the suction zone extends into the water of the receiving tank, and the conduit conducting the water removed in the filtration zone leads above the water level in the receiving tank. The preceding sections (33) to (40) characterized by
The device described above.

(42), the entire device is constructed as a unit that is transportable and can be installed anywhere, and the receiving tank is within its range (1
), (2), and the device according to any two of the preceding items (33) to (41).

[Brief explanation of drawings]

Fig. 1a is a schematic explanatory diagram of the device of the present invention, Fig. 1b11 is an explanatory diagram showing detailed modifications of the filtration zone, and Fig. 2 is a schematic diagram of the device of the present invention having a different configuration from the device in Fig. 1d. It is an explanatory diagram. 10...Filtration zone, 12...Suction zone, 14...Compression 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...Cleaning device, 74...
... Paper band, 75 ... Conveyor belt,
16...tank, 7γ...fresh water utilization device, 79...drum controller, 80...pa tension roller, 84...trap,
88...Vacuum pump, 90...Tank, 94...°...Rod. Procedural amendment written format) July 1, 1985 1, Indication of the case 1985 Patent Application No. 69981 2, Title of the invention Sludge dewatering device 3, Person making the amendment Relationship with the case Patent applicant name Name Kubota Tekko 4 Co., Ltd., Agent 1-1-14 Shinjuku, Shinjuku-ku, Tokyo
No. Yamada Building 5, date of amendment order June 4, 1986 (1) Appropriate drawings clearly drawn in black will be supplemented as shown in the attached sheet. (No change in content) (2) Supplement the power of attorney as shown in the attached document.

Claims (4)

[Claims] (1) A sludge dewatering device in which sludge is continuously transported from a filtration zone to a suction zone by an endless screening belt, and the sludge from which a portion of water has been removed in the filtration zone is transported through the endless screening belt. It consists of a suction chamber provided in the suction zone for suctioning moisture, and a suction means for generating low pressure in the suction chamber, and the suction chamber is subdivided into several chambers, and the suction chamber is subdivided into several chambers. The device characterized in that the low pressure increases in the direction of travel of the endless screening belt. (2) The sludge dewatering apparatus according to claim (1), wherein the suction means includes a suction pump, and the connecting pipe line thereof opens above the side of the suction chamber. (3) The suction chamber communicates with the receiving tank via a pipe, and the pipe extends below the water surface of the receiving tank and is formed as a pressure measuring pipe in the suction chamber. A sludge dewatering device according to claim (2). (4) Claims (1) to (3) characterized in that the drain port of the receiving tank is installed at a high position so that the water level in the receiving tank is maintained constant. The sludge dewatering device according to any of the paragraphs.