JP2535110Y2 - Sludge dewatering equipment - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a sludge dewatering apparatus for dewatering sludge using a screw dewatering machine or a belt dewatering machine equipped with a filter cloth belt. Regarding what is done.

[0002]

2. Description of the Related Art Conventionally, as this type of sludge dewatering apparatus, for example, the compression pressure at the end of a screw shaft and the filtration flow rate leached from a dewatering cylinder are individually detected, and the rotation speed of the screw shaft is adjusted in accordance with both detected values. A control device has been proposed (see, for example, JP-A-61-162298).

[0003]

However, in the above-described device, not only is it difficult to accurately perform the detection operation itself, but also because the control is performed using two detection values, the configuration of the control unit is not limited. There are also many practical problems, such as complexity.

[0004] The present inventor has made a study in view of such a problem. As a result, if the amount of the polymer flocculant is adjusted in accordance with the specific gravity of the sludge, the sludge can be coagulated well, and the screw is adjusted in accordance with the specific gravity of the sludge. The specific gravity measurement of sludge is an important factor in any control, such as the cake with a constant moisture content can be discharged if the rotation speed of the filter cloth or the traveling speed of the filter cloth belt is set. It has been found that by measuring the weight, the change in specific gravity of sludge itself can be easily and accurately measured.

The present invention has been made based on the above findings, and provides a sludge dewatering apparatus capable of relatively accurately controlling sludge aggregation and controlling the water content of cake while maintaining a simple structure. The purpose is to:

[0006]

According to the present invention, as schematically shown in FIG. 1, the basic structure of the polymer coagulant 18 and the polymer coagulant sent from the supply unit 14 are shown. 18 and the sludge 16 to be dewatered are mixed and agglomerated, and the reaction tank 40 from which the agglomerated sludge 48 is taken out while overflowing, and the screw is rotated to compress and dehydrate the agglomerated sludge 48 sent from the reaction tank 40. Screw dewatering machine 22 and coagulated sludge 48 inside thereof
And a measuring unit 26 capable of outputting a signal corresponding to the total weight of the reaction tank 40 including the reaction vessel 40, and the polymer flocculant 1 sent from the supply unit 14 corresponding to the signal output from the measuring unit 26.
8 and a control unit 28 that can control the supply speed of the screw 8 and the screw rotation speed of the screw dehydrator 22.

When a belt dehydrator 23 is used in place of the screw dehydrator 22, the supply speed of the polymer coagulant 18 sent from the polymer coagulant supply unit 14 and the filter cloth belt 53 of the belt dehydrator 23 The running speed is controlled by the control unit 28.

[0008]

In the above construction, sludge 1 is placed in the reaction tank 40.
The polymer flocculant 18 is sent to the screw dehydrator 22 while overflowing from the reaction tank 40 after the sludge 16 flocculates at a ratio corresponding to the water content and the amount of the polymer flocculant 18. The cake 62 that has been sent and compressed and dehydrated to a predetermined moisture content is discharged.

Here, the reaction tank 40 is supplied with the sludge 16 to be supplied.
As a result, the volume stored in the reaction tank 40 is always constant. On the other hand, the weight of the entire reaction tank 40 including the internal coagulated sludge 48 is constantly measured by the measuring section 26, and the change in the weight is proportional to the specific gravity of the coagulated sludge 48.

The control unit 28 uses a signal corresponding to a value proportional to the specific gravity of the coagulated sludge 48 sent from the measuring unit 26 to supply the polymer coagulant 18 per unit time and the rotation speed of the screw 58. Is controlled according to a previously set procedure, so that the cake 62 having a predetermined moisture content is automatically discharged from the screw dehydrator 22.

In the case of the belt dehydrator 23, the control unit 28 controls the supply speed of the polymer flocculant 18 per unit time and the running speed of the filter cloth belt 53 according to a predetermined procedure.

[0012]

As described above, the specific weight of the coagulated sludge 48 is obtained by measuring the total weight of the reaction tank 40 including the internal coagulated sludge 48, and the specific gravity of the polymer coagulant 18 is determined in accordance with the measured specific gravity. Since the supply amount per unit time and the rotation speed of the screw 58 of the screw dewatering machine 22 or the traveling speed of the filter cloth belt 53 are controlled, relatively accurate coagulation control and water content are maintained while maintaining a simple structure. Rate control can be performed.

[0013]

1 to 3 show a first embodiment of a sludge dewatering apparatus 10 according to the present invention.
An embodiment is shown, as shown in FIG. 2, a supply section 12 for sludge 16, a supply section 14 for a polymer flocculant 18,
A reaction unit 20 for the polymer coagulant 18, a screw-type dehydrator 22, a discharge unit 24 for sending the processed material in the screw dehydrator 22 to the outside, a measurement unit 26 for detecting various states of the apparatus, and a measurement unit And a control unit 28 that performs a control operation corresponding to the detection result of 26.

The sludge supply section 12 supplies the sludge 16 sucked up by using the submersible pump P1 from above into a raw water tank 32 provided with a stirrer 30, while supplying the sludge 16 from below to the supply pump P2.
The sludge 16 is supplied toward the upstream side of the reaction unit 20 by using the method.

The polymer flocculant supply section 14 is provided with two polymer tanks 36 and 38 each having a stirrer 34.
6.38 A flocculant A. A polymer flocculant diluted with water
B are separately stored, and two types of coagulation liquids A and B are individually sent to the reaction section 20 using the polymer tank pumps P3 and P4.

The reaction section 20 comprises two types of coagulation liquids A and B
In response to the above, two reaction tanks 40a and 40b each having a stirrer 39 are provided.
Oa and 40b are integrally formed by connecting one side wall 42 in common with each other. Here, the first
The reaction tank 40a has a larger peripheral wall surface 44 than the second reaction tank 40b.
However, since the lower surfaces 46 of both the reaction tanks 40a and 40b are located on the same plane, when the sludge 16 is sent from the sludge supply unit 12 to the first reaction tank 40a side, the first reaction tank 40a The sludge 16 mixed with one coagulation liquid A overflows and then collects in the second reaction tank 40b, where it is coagulated by being mixed with the other coagulation liquid B, and also overflows the second reaction tank 40b. It flows into the screw dehydrator 22.

The screw dewatering machine 22 moves from a sludge supply zone 50 provided on the base end side to a discharge port 52 on the front end side.
A screw 58 having spiral blades is rotatably provided in a dewatering cylinder 56 in which the diameter of a draining zone 54 at the intermediate portion is gradually reduced. Furthermore,
A motor M is provided at the base end of the screw shaft 60, and the control unit 2
The rotation speed can be changed by a signal from the control unit 8.

Therefore, the coagulated sludge 48 sent from the second reaction tank 40b to the sludge supply zone 50 is
8 moves forward in conjunction with the rotation of
6 and is gradually dehydrated through the draining zone 54 and discharged from the discharge port 52 as a cake 62 having a predetermined moisture content.

The discharge section 24 is provided with a belt conveyor 64 below the discharge port 52 of the screw dewatering machine 22, and shifts the formed cake 62 to a predetermined position. On the other hand, a water conduit 66 is provided so as to cover the lower part of the draining zone 54, and after the dehydrated water is introduced into the drainage tank 68, the drainage pump P
5, while a large part of the sludge is supplied to the outside, while a part of the sludge is returned to the raw water tank 32 of the sludge supply unit 12 through the circulation pump P6.

The measuring section 26 is provided in the raw water tank 3 of the sludge supply section 12.
2 and one in each of the sludge supply zones 50 of the screw dewatering machine 22, and the level gauges 70 and 72 are provided between the lower surface 46 and the installation surface 73 of the first and second reaction tanks 40 a and 40 b. And four load cells 74 provided.

The level meters 70 and 72 send a predetermined signal to the first or second control circuit 76 or 78 when the liquid level exceeds a preset upper limit value or falls below a lower limit value. The load cell 74 determines the specific gravity of the coagulated sludge 48 in the reaction tank 40 by allowing the total weight of the sludge to be measured in a state where the sludge is stored in the reaction tank 40 by a certain volume. , And sends a signal of a value corresponding to the detected load to the third control circuit 80.

The above-mentioned first control circuit 76 is provided in the raw water tank 32.
The submersible pump P1 is controlled to be on / off by a signal sent from the level meter 70 in the inside so that the water level in the raw water tank 32 falls within the lower limit and the upper limit. Also, the second control circuit 78
Is linked with the detection operation of the level meter 72 in the screw dehydrator 22, and the polymer tank pump P of the polymer condensing agent supply unit 14
3. P4 and the supply pump P2 of the sludge supply unit 12 are controlled to be on and off so that the amount of the coagulated sludge 48 supplied to the screw dewatering machine 22 is controlled to be substantially constant.

The present invention is characterized by the control operation in the third control circuit 80 using the load cell 74 described above. The rotation speeds of the molecular bath pumps P3 and P4 and the rotation speed of the motor M of the screw dehydrator 22 are simultaneously controlled.

The third control circuit 80 uses the load data output from the four load cells 74 as shown in the block diagram of FIG. The total weight of the reaction tank 40 is determined. Further, in the specific gravity determination unit 84, the reaction tank 40 determined in advance is used.
The specific gravity is obtained from the data on the own weight and volume, and is input to the comparing unit 86.

The comparison unit 86 sets the upper and lower limits of the specific gravity as comparison data in advance, and when the measured value exceeds the upper limit or falls below the lower limit, a signal corresponding to the measured value exceeds the upper limit or the lower limit. It is sent to the motor drive unit 90 and the polymer tank pumps P3 and P3 are
4 and the rotation speed of the motor M can be controlled.

That is, when the specific gravity of the coagulated sludge 48 in the reaction tank 40 is lower than the lower limit, the amount of water occupying the coagulated sludge 48 is larger than the standard value and the ratio of the solid content is reduced. And the rotation speeds of the polymer tank pumps P3 and P4 are reduced below a predetermined value so that the coagulation liquids A and B for the coagulation sludge 48 are reduced.
Is reduced, the rotation speed of the motor M is reduced below a predetermined value, the transfer speed of the coagulated sludge 48 in the screw dewatering machine 22 is reduced, and the amount of dewatering from the coagulated sludge 48 is increased.

Conversely, if the specific gravity of the coagulated sludge 48 exceeds the upper limit, the amount of water occupying the coagulated sludge 48 is reduced below the standard value, indicating that the proportion of solids is increased. The rotational speeds of P3 and P4 are increased from a predetermined value to increase the supply amounts of the coagulating liquids A and B to the coagulated sludge 48, while the rotational speed of the motor M is increased to a predetermined value and the coagulated sludge in the screw dewatering machine 22 is increased. By increasing the transfer speed of 48 and reducing the amount of dewatering from the coagulated sludge 48,
The moisture content of the cake 62 finally obtained is automatically kept substantially constant regardless of the increase or decrease of the water content contained in the coagulated sludge 48.

(Second Embodiment) FIG. 4 shows a belt dehydrator 2 instead of the screw dehydrator 22.
3 is schematically shown. The belt dehydrator 23 includes a filter cloth belt 53 stretched between rollers 51a and 51b,
Press rollers 55a and 55
and a press belt 57 stretched between b. The filter cloth belt 53 allows only the water in the sludge to pass through, and the water is guided to the water conduit 66 via the tray 59.

The roller 51a on the side of the filter cloth belt 53 is driven to rotate by a motor M, and the traveling speed of the filter cloth belt 53 can be changed by a signal from the control unit 28. Coagulated sludge 48 sent from the reaction tank 40 onto the filter cloth belt 53
Is gradually dehydrated by being compressed between the belts 53 and 57 as the filter cloth belt 53 and the press belt 57 travel, and is discharged as a cake 62 having a predetermined moisture content.
Of the belt conveyor 64. Third control circuit 80
Controls the running speed of the filter cloth belt 53 by controlling the rotation speed of the motor M while controlling the polymer tank pumps P3 and P4 as described above.

When the specific gravity of the coagulated sludge 48 in the reaction tank 40 falls below the lower limit, the rotation speed of the motor M is reduced to reduce the traveling speed of the filter cloth belt 53. Thereby, the filter cloth belt 5
The dewatering time of the agglomerated sludge 48 is increased by increasing the dewatering time of the agglomerated sludge 48 on 3. Conversely, flocculated sludge 48
When the specific gravity exceeds the upper limit, the rotation speed of the motor M is increased to increase the traveling speed of the filter cloth belt 53. Then, the dewatering time of the coagulated sludge 48 on the filter cloth belt 53 is shortened, and the amount of dewatering from the coagulated sludge 48 is reduced.

The rotation speeds of the polymer tank pumps P3 and P4 and the motor M are not limited to being changed stepwise, but may be changed steplessly. It goes without saying that various types of measuring means may be used in place of the load cell 74 for measuring the weight of the reaction tank 40. Further, the press belt 57 in the belt dewatering machine 23 is omitted, and a suction device connected to a vacuum pump is arranged at a position corresponding to the tray 59, and the moisture in the sludge is sucked from the back side of the filter cloth belt 53. Is also good. If the suction force is constant, the filter cloth belt 5
Since the suction time of the moisture is changed by the increase / decrease control of the traveling speed of 3, the moisture content of the cake 62 can be adjusted.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram for explaining the present invention in principle.

FIG. 2 is a schematic diagram of the entire configuration showing a first embodiment of the present invention.

FIG. 3 is a block diagram illustrating an example of a third control unit.

FIG. 4 is a conceptual diagram illustrating another embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 12 sludge supply unit 14 polymer coagulant supply unit 16 sludge 18 polymer coagulant 20 reaction unit 22 screw dehydrator 23 belt dehydrator 24 discharge unit 26 measuring unit 28 control unit 40 reaction tank 48 coagulated sludge 58 screw 60 screw shaft 62 cake

Claims (2)

(57) [Scope of request for utility model registration] 1. A supply section 14 for a polymer flocculant 18, a polymer flocculant 18 and sludge 16 sent from the supply section 14.
And a coagulated sludge 48, and a reaction tank 40 from which the coagulated sludge 48 is taken out while overflowing; a screw dehydrator 22 for rotating a screw to compress and dewater the coagulated sludge 48 sent from the reaction tank 40; A measuring unit 26 capable of outputting a signal corresponding to a change in the total weight of the reaction tank 40 including the internal flocculated sludge 48; and a reaction tank corresponding to the signal output from the measuring unit 26, A sludge dewatering device comprising: a control unit 28 capable of controlling the supply speed of the polymer flocculant 18 sent to 40 and the screw rotation speed of the screw dewatering device 22. 2. A supply section 14 for a polymer flocculant 18, a polymer flocculant 18 and sludge 16 sent from the supply section 14.
And the flocculation sludge 48 is taken out while overflowing, and the filter cloth belt is driven to run, and the flocculated sludge 48 sent from the reaction tank 40 is dewatered via the filter cloth belt. A belt dehydrator 23, a measuring unit 26 capable of outputting a signal corresponding to a change in the total weight of the reaction tank 40 including the coagulated sludge 48 therein, and a signal corresponding to the signal output from the measuring unit 26. A sludge dewatering apparatus comprising: a control unit 28 capable of controlling a supply speed of the polymer flocculant 18 sent from the supply unit 14 to the reaction tank 40 and a traveling speed of the filter cloth belt of the belt dehydrator 23.