JPS589798A - Belt press type sludge dehydrating device - Google Patents

Abstract

PURPOSE:To increase dehydrating effect remarkably by piercing many drip holes on a pressure belt and providing many minute projections on both faces of the belt in parts other than the drip holes. CONSTITUTION:Many drip holes 403 are pierced through a pressure belt 402 of a high pressure dehydration section 400 of a belt press type sludge dehydrating device, and many minute projections 404 are provided on both sides in parts other than the holes. Sludge 3 held between filter cloths 4, 5 is subjected to pressure higher than that in an intermediate pressure dehydration section 300 by tension of the pressure belt 402 and compressed and dehydrated. Dehydrated water is discharged from drip holes 406, 403 of pressure rolls 401, 402. At this time, projections 404 on the pressure belt 402 bite into the filter cloth 5 to help dehydration and prevent slipping of the pressure belt 402.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a belt press type sludge dewatering device.

Belt press type dehydrators have been widely used for dewatering sludge. Conventional belt press type dehydrators are designed for sludge drawn from a sludge thickening tank, and generally supply sludge with a concentration of 1 to 34.

In addition, if such low-concentration sludge liquid is directly supplied to a belt press type dehydrator by any method, the sludge escapes in both the horizontal and vertical directions and the throughput decreases. In the gravity method, the sludge concentration is increased using a vacuum method and then supplied to the belt press type dehydrator.In the gravity method, the sludge is supplied onto a filter cloth that moves uphill, and water is separated by gravity. It is something that makes you In the vacuum method, water is passed through a reduced pressure chamber made of filter cloth, and water is separated using vertical pressure in addition to gravity. Although these methods are relatively efficient for dilute sludge liquids, they are not very useful in increasing the overall concentration, and the sludge concentration increases by only 1 to 2 degrees.

Conventionally, these sludges have been treated with various belt press type dewatering machines. Belt press types include opposed roll type, horizontal roll type, and pressure roll type. In both methods, sludge is sandwiched between two filter cloths and passed through a roll. In the opposed roll method, the filter cloth is passed between two opposing rolls, and in the horizontal roll method, the filter cloth is bent along the curved surface of the roll, and the pressure on the roll curved surface generated by the tension of the filter cloth is used. Since there is a limit to the tension of the filter cloth, in the pressure roll method, the filter cloth is pressed from above by a pressure belt which is stretched under even greater tension. The pressure roll method has high dewatering efficiency, so it has been increasingly used recently.

In any type of belt press type dehydrator, it is important to prevent sludge from escaping laterally between the two filter cloths, that is, from side leaking and from escaping backwards.

For this reason, it is necessary to select an appropriate supply sludge concentration, applied pressure, and processing amount for the belt press type dehydrator, and more specifically, for each method; as well as an appropriate side leak prevention mechanism and backflow prevention as necessary. The object of the present invention is to provide a belt press type sludge dewatering device that prevents side leakage and backflow of sludge, has high processing capacity, and can obtain dehydrated sludge with a low water content. There's something to do.

The belt press type sludge dewatering device according to the present invention has the following (a)
This is a device characterized by having the components shown in (e).

(Al Consists of a low-pressure dehydration section, a feeding section, a medium-pressure dehydration section, and a high-pressure dehydration section.

(bl The low-pressure dewatering section consists of two rotating endless filter cloths supported by a plurality of pressure rolls that rotate up and down at the same speed, and the rotating endless filter cloths 2 & 3 are located on the downstream side from the upstream side. A band-shaped elastic body is provided on the side edge of each endless filter cloth, and a guide is attached to the mountain side of the band-shaped elastic body, and the sludge to be treated is supplied to the upstream side. Then, low-pressure dewatered sludge is discharged from the downstream side.

(C) The feeding section consists of a receiving section and a feeding device, and the receiving section gradually reduces the distance between the two rotary endless filter cloths (in a wedge-like manner) to sandwich the sludge from the low-pressure dewatering section; After passing through the feeding device and the medium/high pressure dewatering section, they are separated and the dehydrated sludge on the filter cloth is dropped, and each is returned to the receiving section, where the budding sludge enters the feeding device from the upstream side of the receiving section. Guide plates for preventing side leaks are provided in contact with the inner sides of both side edges of the two rotating endless filter cloths, and the feeding device has at least three rolls rotatably attached to coaxially move a circumferential orbit. The system is driven to forcefully send sludge from the receiving section to the medium pressure dewatering section.

(d) The medium pressure dewatering section is constructed by bending two filter cloths sandwiching the sludge along the curved surfaces of one or more rolls.

(e) The high-pressure dewatering section bends two filter cloths that sandwich the sludge that has passed through the medium-pressure dewatering section along the curved surface of a roll having a large number of holes on the circumference, and An endless pressure belt that rotates and is stretched with a certain tension from the filter cloth.
A high-pressure dehydration section is constructed by wrapping the filter cloth over the two filter cloths that are wrapped around the rolls.

In a preferred embodiment of the sludge dewatering device according to the present invention,
A large number of drain holes are formed in the pressure belt, and a large number of minute protrusions are provided on both sides of the pressure belt at locations other than the drain holes.

In another preferred embodiment of the sludge dewatering apparatus according to the present invention, the pressure rolls of the high-pressure dewatering section are thread-shaped.

The low-pressure dewatering section, medium-pressure dewatering section, and high-pressure dewatering section of the sludge dewatering apparatus of the present invention employ a belt press-type opposed roll system, horizontal roll system, and pressure roll system, respectively. That is, since the sludge liquid supplied to the first-stage low-pressure dewatering section has a relatively low concentration, when a large pressure is applied, sludge escape such as side leakage occurs. Therefore, in the low-pressure dewatering section, a gap is maintained between the two filter cloths, and the gap is tapered, so that the pressure applied by the pressure roll corresponds to the filtration speed of the low-concentration sludge, thereby eliminating the return of the sludge. The side edges of the filter cloth are sealed with a belt-shaped elastic material to prevent side leaks.

The taper of the gap is formed by the inclination of the upper and lower filter cloths, most preferably by the lower sloped filter cloth and the upper horizontal filter cloth. The slanted filter fabric may be formed by an upper slanted filter fabric and a lower horizontal filter fabric.

The water content of the dehydrated sludge discharged from the low-pressure dewatering section is approximately 85 壬, or at least 90 yu. Although there is a risk of side leaks due to pressurization (pressurization), since the moisture content has decreased, there is no need for complete sealing as in the low-pressure dehydration section.

Although it depends on the state of the sludge, when the moisture content reaches 80-something or is reduced to 80-4 by horizontal roll dewatering, there is almost no possibility of side leaks. Therefore,
In the apparatus of the present invention, the counterfeit sludge entering the feeding device from the upstream side of the receiving section is dehydrated to a water content of approximately 804 or less.

In the high-pressure dewatering section, the sludge is approximately 754 g
dehydrated to a moisture content of Even if the sludge supplied to this device has a low water content, that is, the dewatering rate has decreased in the previous step, it is possible to obtain dehydrated sludge with a water content of approximately 8 (1 or less).

EMBODIMENT OF THE INVENTION Hereinafter, the apparatus of this invention will be explained in detail based on the drawing of an Example. FIG. 1 is a block diagram of an embodiment of the apparatus of the present invention. In FIG. 1, 100 is a low-pressure dehydration section, 200 is a feeding section, 300 is a medium-pressure dehydration section, and 400 is a high-pressure dehydration section. The low-pressure dewatering section 100 is provided with an endless filter cloth 101 with the inclined part 102 on the lower side, driven by a driving roll 106, stretched between the driving roll 106, a driven roll, and a guide roll 104, and rotating in the direction of the arrow. It is rare. The dewatering section 102 of the filter cloth 101 is provided with a pressure roll 10 in addition to the guide roll 104.
A similar endless filter cloth 106 is stretched between a driving roll 107, a driven roll, and a guide roll 108 above the filter cloth 101, and rotates in the direction of the arrow. Filter cloth 101 The gap between the filter cloth 106 and the lower side of the filter cloth 106 is approximately 60 t-1 on the upstream side (left side) of the dewatering section 102, and gradually decreases as it goes downstream (right side) to approximately 20 t-1 at the downstream end.Filter cloth 10
1 and 106 are provided with a roll 109. The thickened sludge is passed through the dewatering section 10 of the filter cloth 101 from the direction of arrow 1.
The dehydrated sludge is supplied to the upstream side of 2, and the dehydrated sludge is supplied from the downstream side to the arrow 2.
is ejected in the direction of

On each side edge of the endless filter cloth 101, 106, a second
As shown in the figure, a band-shaped elastic body 110 such as rubber is attached. In FIG. 2, 3 is sludge during dewatering. The thickness of the band-shaped elastic body is slightly smaller than the maximum value of the gap between the filter cloths 107 and 106, 1/2 (20 m in the example). Further, on the inside surface of the band-shaped elastic body, a guide that gradually decreases from the upstream side to the downstream side is provided inscribed in the elastic body to prevent sludge from leaking from gaps in the elastic body. Therefore, the band-shaped elastic body 110 has both filter cloths 101 and 106.
They are pressed against each other in the gap and come into close contact with each other, and even if pressure is applied to the sludge 3, it will not leak from the paddle.

Thickened sludge supplied from arrow 1 passes through both filter cloths 101106
Since the gap is as wide as 60 fins (the conventional one is 1 to IDm), the filter cloth is smoothly fed into the gap as it moves. The sludge 3 in the gap is slightly pressurized because the cross-sectional area of the gap is gradually reduced and the filter cloths 101, 106 are pressed down by pressure rolls 105, 109, and dewatering is promoted. By appropriately selecting the gap distance, inclination, belt speed, supply amount of thickened sludge, etc., it is possible to process a considerable amount of thickened sludge at a high dewatering rate without causing backtracking in the sludge dewatering section.

Next, this device is dehydrated in a low pressure dehydration section 100,
The low-pressure dewatered sludge discharged in the direction of arrow 2 is held between the feeding section 200, medium-pressure dewatering section 300, and high-pressure dewatering section 400.
2 & rotary endless filter cloths 4.5 are provided. The filter cloths 4 and 5 gradually reduce their mutual spacing in a wedge-like manner in the receiving section 201, sandwich the sludge, and are integrated into the feeding device 202.
After passing through the intermediate pressure dewatering section 300 and the high pressure dewatering section 400, the filter leaves and drops the dehydrated sludge on the filter cloth (the falling direction of the dehydrated sludge is shown by arrow 7), and returns to the receiving section 201 again.

Further, as shown in FIG. 3, guide plates 8.8 are provided in contact with passages on both sides of the budding filter cloth 4.5 entering the feeding device 202 from the receiving portion 201. This prevents side leakage of the sludge 3.

The filter cloth 4.5 holding the sludge 6 is first transferred to the feeding device fi2.
Enter 02. When the sludge filterability is particularly poor, the feeding device 202 depressurizes the sludge holding filter cloth 4.5 by passing through a pressure roll and a guide roll, and the held sludge escapes backward.
This is a device that forcibly feeds sludge forward in order to prevent the sludge from being compressed and dehydrated and the amount of sludge to be processed decreases.

Any kind of feeding device may be installed in the tampering crisis, but
In the example, a feeding device as shown in FIG. 4 was used.

The feeding device 202 has at least six small diameter rolls 20.
3 (three in the example), and the sludge 3 is sandwiched in a space sealed with two rolls and two filter cloths 4.5,
The six small rolls 206 of the feeding device 202 are rotated and coaxially driven in a circular orbit, thereby dewatering the sludge, preventing the sludge from escaping backwards, and forcing the sludge into the medium. Send it to the pressure dewatering section.

The medium-pressure dewatering section 600 is provided with one compression roll 301 (cylindrical or pinch-shaped) and a plurality of small rolls 602. The compression roll 601 is provided with a large number of drainage holes on its circumferential surface. The filter cloth 4.5 holding the sludge 3 is the compression roll 3
The sludge 3 is dewatered by the pressure of the outer filter cloth against the roll curved surface caused by the tension of the filter cloth. The separated water passes through the filter cloth to the outside, and the water that has passed through the inner filter cloth is discharged from the drain hole of the roll 601. Further, when passing along the small rolls 302, since the radius of curvature of the rolls is small, it is subjected to strong compression, and a large shearing force acts due to the displacement of the inner and outer filter cloths, promoting dewatering.

The high-pressure dewatering section 400 includes a pressure roller 4 having a large number of drainage holes 406 on its circumferential surface, similar to the compression roll 301.
01 (cylindrical or chain-shaped) is provided, and the filter cloth 4.5 that has passed through the medium pressure dewatering section 300 is bent along the curved surface of the roll 401. The high pressure dehydration section 400 includes
Further, an endless pressure belt 402 is stretched between a driving roll, a driven roll, and a guide roll 405 with a tension greater than the tension of the filter cloth 4.5, and is further wrapped around a pressure roller 401.

Furthermore, the endless pressure belt 402 rotates at the same speed as the filter cloth 4.5. The endless pressure belt 402 is made of a flexible material with high tensile strength, such as a rubber plate. An example of the pressure belt is shown in FIGS. 5 and 6. This pressure belt 40
The sludge 3 sandwiched between the filter cloths 4.5 in the high-pressure dewatering section 400 has a large number of drain holes 403 drilled in it, and a large number of minute protrusions 404 on both sides other than the drain holes 406.
Due to the tension of the pressure belt 402, the medium pressure dewatering section 300
It is compressed and dehydrated under even greater pressure.

The dehydrated water is discharged from the drain hole 406 of the pressure roll 401 and the drain hole 403 of the pressure belt 402. At this time, the protrusion 404 of the pressure belt 402 bites into the filter cloth 5,
Promotes dewatering of sludge 3. Also, unlike the filter cloth 4.5, the pressure belt 402 is easily slippery on the roll due to its material.
Protrusions 404 help prevent slipping.

The filter cloth 4.5 that has passed through the high-pressure dewatering section 400 is transferred to a guide roll 9.
．． The dewatered sludge separated at 10 and held by the filter cloth 4.5 is discharged in the direction of arrow 7 by electric power and transferred to a required receiver or conveyance means. Each filter cloth 4.5 is provided with a scraping knife (not shown) for draining the dewatered sludge.

The rotation paths of the endless filter cloths 4.5 and 101.106 are provided with cleaning means, drive rolls, tension adjustment rolls, etc. Furthermore, the endless filter cloths 4.5 are provided with meandering prevention rolls (not shown). , these are commonly used, so their explanation will be omitted.

Next, an example will be described.

Using the device of the present invention, sludge was extracted from an aeration tank at a sewage treatment plant in Saitama Prefecture and concentrated using an atmospheric flotation device (when using this device, the sludge concentration was approximately 5 to 10%).
thickened sludge can be obtained. ), the results shown in Table 1 were obtained.

Experimental conditions for the dehydrator 1) Filter cloth width 200mm 2) Low pressure section inflow thickness 60mm 3) Low pressure section outlet thickness 20mm 4) High pressure section outlet thickness 5mm 5) Filter cloth speed Solid concentration of supplied sludge 4.14 0.8
m/lni n5.64 0.7 bow 4 moe n 78% Q, 5 u n 6) High pressure section pressurizing force 4.6 kg/crrf Table 1 As is clear from Table 1, the dewatering device of the present invention When using a conventional belt press type dehydrator, it is possible to process 2 to 3 times more solids than a conventional belt press type dehydrator.

*m indicates the length (m) in the filter cloth.

The belt press type sludge dewatering apparatus of the present invention is constructed and used as described above. In the apparatus of the present invention, a belt press type opposed roll system, horizontal roll system, and pressure roll system are skillfully incorporated in accordance with the dewatering state of the sludge.
It is equipped with the necessary means and divided into a low-pressure dewatering section, a feeding section, a medium-pressure dewatering section, and a high-pressure dewatering section.In particular, the low-pressure dewatering section is separated from the others, so that side leaks and backflow of sludge are prevented.
It has high processing capacity and can obtain dehydrated sludge with low moisture content. , *When using concentrated sludge with a sludge concentration of 5 to 104 in addition to the atmospheric flotation device, the device of the present invention can significantly improve efficiency compared to conventional belt press type dehydrators. can.

[Brief explanation of the drawing]

Fig. 1 is a configuration diagram of an embodiment of the apparatus of the present invention, Fig. 2 is a cross-sectional view showing the sludge holding state of the filter cloth in the low-pressure dewatering section, and Fig. 3 is a sectional view showing the filter cloth in the area provided with the guide plate. 4 is a sectional view of an embodiment of the feeding section; FIGS. 5 and 6 are a partial plan view and a sectional view of an embodiment of the pressure belt; FIG. 7 is a sectional view of the embodiment of the pressure belt; It is a schematic front view of a cylindrical pressure roll, and FIG. 8 is a schematic front view of a pinch-shaped pressure roll. 6...Sludge during dewatering 4.5...Endless filter cloth 8...Guidance board 100...
Low pressure dehydration section 101.106... Endless filter cloth jQ
2-...°°8 ahead (download 105.109...
Pressure roll 110... Band-shaped elastic body 200... Feeding section 201... Song receiving section 202... Feeding device 600...
... Medium pressure dehydration section 301 ... Compression roll 30
2...Small roll 400...High pressure dewatering section 401...Face pressure roll 402...Pressure belt 406...Bending water extraction hole book 2 figure'! -, 3 figure tail 4 figure 02 4θ1 4θl

Claims (1)

[Claims] 111a) Consists of a low-pressure dewatering section, a feeding section, a medium-pressure dehydrating section, and a high-pressure dehydrating section; (b) The low-pressure dehydrating section is supported by a plurality of pressure rolls that rotate up and down at the same speed. The two rotatable endless filter cloths are separated from each other by an interval that gradually decreases from the upstream side to the downstream side, and the gA1 of each endless filter cloth is
A band-shaped elastic body is provided on one edge, and a guide is attached to the mountain side of the limb band-shaped elastic body, and the sludge to be treated is supplied to the upstream side, and the low-pressure dewatered sludge is discharged from the downstream side; (C) Feeding section consists of a receiving section and a feeding device, and the receiving section gradually reduces the distance between the two rotating endless filter cloths (in a wedge-like manner), and the sludge from the low-pressure dehydration section is integrated into the feeding device. After passing through the medium/high-pressure dewatering section, the two rotating sheets separate to drop the dehydrated sludge on the filter cloth, return them to the receiving section, and enter the feeding device from the upstream side of the receiving section. Guide plates are provided in contact with the inner sides of both sides of the endless filter cloth to prevent side leaks, and the feeding device has at least three rolls rotatably attached to coaxially drive a circumferential orbit, and the feeding device is configured to rotate a circumferential track from the receiving portion. The sludge is forcibly sent to the medium-pressure dewatering section; (e) The high-pressure dewatering section bends two filter cloths sandwiching the sludge that has passed through the medium-pressure dewatering section along the curved surface of a roll having a large number of holes perforated on the circumferential surface, and An endless pressure belt that rotates and is stretched with greater tension than two filter cloths.
A belt press type sludge dewatering device characterized in that a high-pressure dewatering section is constructed by stretching over two filter cloths stretched over the rolls. (21) The belt press type according to claim 1, wherein the pressure belt is provided with a large number of drain holes, and a large number of minute protrusions are provided on both sides of the pressure belt at locations other than the drain holes. Sludge Dewatering Apparatus, (a) 3) The belt press type sludge dewatering apparatus according to Claim 1 or 2, wherein the compression rolls of the medium pressure dehydration section are in the form of a chain. (41) The belt press type sludge dewatering device according to any one of claims 1 to 3, wherein the pressure rolls of the high-pressure dewatering section are chain-shaped.