JP6691349B2 - Belt dehydrator - Google Patents

Description

  TECHNICAL FIELD The present invention relates to a belt dehydrator that pressurizes and dehydrates an object to be treated such as sludge between two endless filter cloths by a plurality of pressure rollers.

  A belt dehydrator is known as a device for depressurizing and dehydrating an object to be treated such as sewage sludge. The belt dehydrator is a device that filters sludge and other objects to be treated using an endless belt-shaped filter cloth, and a gravity filtration unit that concentrates the objects to be treated by gravity filtration and two objects to be treated with filter cloth. And a pressure filtering unit that winds around a plurality of pressure rollers so as to meander and is dehydrated under pressure.

  It is known that in a belt dehydrator, when pressure is applied in a pressure filtration unit, a phenomenon in which an object to be processed flows out from the side end portions of two filter cloths, a so-called side leak phenomenon occurs. Various belt dehydrators have been developed in order to suppress the side leak phenomenon.

  For example, in Patent Document 1, as a belt dehydrator for preventing a side leak phenomenon, some of a plurality of rollers supporting an endless belt are provided with an indentation so as to be located at a central portion in the axial direction of the rollers. Is described. The action of this dehydrator is to prevent the side leak phenomenon by providing the support roller forming the gravity filtration portion with the depression so that the sludge is brought close to the center portion of the filter cloth.

JP-A-6-190595

However, in reality, the side leak phenomenon cannot be completely prevented, and the side leak phenomenon occurs depending on the state of the object to be treated such as sludge. The object to be treated (hereinafter, simply referred to as "side leak") flowing out from the side end portion of the filter cloth falls and accumulates on the drain pan that receives the filtrate and the like. Therefore, the accumulated side leak was removed by regularly performing cleaning work.
An object of the present invention is to suppress the accumulation of side leak in the machine and to simplify the cleaning work.

The present inventor, as a result of diligent study on the above problems, in a belt dehydrator for filtering an object to be processed using an endless belt-shaped filter cloth, a trough is arranged at a position where a side leak falls to a side inside the trough. The present invention has been completed by finding that it is possible to suppress the accumulation of the side leak in the belt dewatering machine by collecting the leak and supplying the cleaning water to wash the side leak in the trough.
Specifically, it is the following belt dehydrator.

  The belt dehydrator of the present invention for solving the above problems is a belt dehydrator that filters an object to be processed using an endless belt-shaped filter cloth, and side leaks flowing out from side end portions of the filter cloth fall. The drain pan is equipped with a drain pan and cleaning water supply means for supplying cleaning water for cleaning the side leak that has dropped into the drain pan. The drain pan is provided with a trough at a position where the side leak falls.

According to the belt dehydrator of the present invention, when the side leak flows down from the side end of the endless belt-shaped filter cloth, the side leak is collected by the trough arranged in the drain pan, and the side leak collected in the trough is washed water. Washed off by. As a result, it is possible to suppress the accumulation of side leak in the machine.
Further, by providing the trough, the side leak can be efficiently washed off with a small amount of washing water.

Furthermore, the present invention is characterized in that the cleaning water contains the filtrate that has passed through the endless belt-shaped filter cloth, or the filter cloth cleaning drainage for cleaning the filter cloth.
The amount of the purified water used can be reduced by collecting the filtrate generated by filtering the object to be treated or the filter cloth cleaning waste water for cleaning the clogging of the filter cloth and using it as the cleaning water. Furthermore, if there is a large amount of filtrate and filter cloth washing drainage, it is not necessary to add additional purified water.

Further, the present invention has a feature that the trough is inclined.
By inclining the trough, the flow of washing water becomes faster, and side leaks with high viscosity can be washed away.

Further, the present invention is characterized in that the troughs are arranged on both sides of the filter cloth so that the side leaks flowing out from both side end portions of the filter cloth fall into the trough.
As a result, the side leaks that have flowed down from both ends of the filter cloth are collected in the trough, so that the side leaks can be completely washed away.

  According to the present invention, in a belt dehydrator that filters an object to be processed using an endless belt-shaped filter cloth, side leaks that have flowed down from the side end portions of the filter cloth can be washed away, thus simplifying the cleaning work inside the machine. can do.

It is a schematic explanatory drawing which shows the structure of the belt dehydrator of the 1st Example of this invention (left side view). It is a schematic explanatory drawing which shows the structure of the belt dehydrator of the 1st Example of this invention (front view). It is a schematic explanatory drawing which shows the structure of the belt dehydrator of the 1st Example of this invention (plan view in XX cross section). It is a schematic explanatory drawing which shows the example of the shape of the trough of the belt dehydrator of this invention. It is a schematic explanatory drawing which shows the structure of the belt dehydrator of the 2nd Example of this invention (left side view). It is a schematic explanatory drawing which shows the structure of the belt dehydrator of the 2nd Example of this invention (front view). It is a schematic explanatory drawing which shows the structure of the belt dehydrator of the 2nd Example of this invention (plan view in a YY cross section).

  The belt dehydrator of the present invention filters an object to be treated using an endless belt-shaped filter cloth. Here, the object to be treated that is provided to the belt dehydrator of the present invention is a state in which a particulate solid is dispersed in a liquid, and a solid having a low solid concentration and a low solid viscosity has a high solid concentration. Includes even things. Specific examples include sewage sludge from sewage treatment plants, surplus sludge from wastewater treatment plants, paper sludge from paper mills, dredging sludge, and sludge.

Hereinafter, embodiments of the belt dewatering machine according to the present invention will be described in detail with reference to the drawings.
[First embodiment]
1 to 3 are schematic explanatory views showing the structure of the belt dehydrator 1a according to the first embodiment of the present invention.
As shown in FIG. 1, the belt dehydrator 1a includes an upper filter cloth 2a and a lower filter cloth 2b formed in an endless belt shape on the upper part thereof. These two filter cloths are composed of a plurality of support rollers 3 ( It is supported by a white circle) and a plurality of pressure rollers 4 (circles with diagonal lines), and forms a gravity filtration section GF and a pressure filtration section PF.

  A drain pan 9a is installed at the bottom of the belt dehydrator 1a. The drain pan is a component for receiving the filtrate filtered by the filter cloth or the filter cloth cleaning drainage for cleaning the filter cloth, and is formed of, for example, a dish-shaped member or the like. Further, the drain pan may be formed by a frame for installing the belt dehydrator or a bottom portion of a casing that constitutes the exterior of the belt dehydrator. The side leak that has flowed out from the side edge of the filter cloth falls into the drain pan.

  The drain pan 9a is provided with troughs 10 at positions where side leaks flowing out from both end portions of the filter cloth fall. The trough 10 is installed so as to be inclined, a water collecting region W partitioned by a weir 13 is formed on the upper end side, and a drain port 12 is installed on the lower end side via a drain flow path 11. Has been done. In the water collecting region W, the filtrate obtained by the endless belt-shaped filter cloth and the filter cloth cleaning drainage generated when cleaning the clogging of the filter cloth are collected. The weir 13 is open at the position of the upper end of the trough 10, and the water collecting region W and the trough 10 are in communication with each other. Therefore, the filtrate and the filter cloth cleaning drainage collected in the water collecting region W are configured to flow into the trough 10 as cleaning water. That is, in the belt dewatering machine 1a of the first embodiment, the water collecting area W that is in communication with the upper end of the inclined trough 10 constitutes the wash water supply means.

  The wash water supply means is means for supplying wash water into the trough. Like the belt dewatering machine 1a of the first embodiment, in addition to a means for supplying a wash water into the trough by gravity by providing a water collecting area at the upper end of the inclined trough, for example, power of a pump or the like is used. Means for supplying cleaning water into the trough may be used. From the viewpoint of energy saving, it is preferable to use a means for supplying washing water into the trough by gravity.

  The washing water may be supplied into the trough from any position of the trough, for example, from the end of the trough as in the first embodiment, or from the side of the trough. May be. The configuration of supplying the cleaning water from the side surface of the trough will be described in detail in the second embodiment.

  Further, the cleaning water may be supplied at any interval as long as the side leak in the trough can be washed away. For example, the wash water may be continuously supplied during operation of the belt dehydrator to form a flow of wash water in the trough, or the wash water may be supplied only when the side leak falls. You may flush the leak. Note that the side leak having a small amount of water and a high viscosity adheres to the trough when it falls into an empty trough and becomes difficult to flow. Therefore, it is preferable to always flush the wash water.

  The wash water is a fluid for washing away the side leak collected in the trough. As in the belt dehydrator 1a of the first embodiment, the filtrate or filter cloth cleaning wastewater may be used as cleaning water, or, for example, purified water may be used. Further, in addition to the filtrate and filter cloth washing drainage, purified water may be used as an auxiliary. From the viewpoint of saving water, it is preferable to use wash water containing filtrate or filter cloth wash drainage.

The trough is a groove formed in the drain pan, and its cross-sectional shape may be any shape as long as it forms a flow of washing water. For example, in addition to having a rectangular shape like the trough 10 of the first embodiment, as shown in FIG. 4, it has a semicircular shape (see (A) and (D)) and a trapezoidal shape (see (B)). , A triangular shape (see (C)), and the like.
Further, the trough may be formed by a gutter 15 placed on a drain pan or a wall 16 as shown in FIGS. 4 (D) and 4 (E).
By providing the trough, a strong flow can be formed with a small amount of fluid, and therefore side leaks can be washed off even with a small amount of washing water.

  Further, the number of troughs is not particularly limited, and two troughs may be formed on both sides of the filter cloth, or only one trough may be formed. It is preferable to form two troughs on both sides of the filter cloth in order to collect all side leaks flowing out from both ends of the filter cloth.

The trough may be installed substantially horizontally, but it is preferable to install it at an inclination. The inclination of the trough increases the flow velocity of the washing water flowing in the trough, so that it can be washed away even when side leak occurs which is highly viscous and easily accumulates.
Furthermore, when the trough is installed with an inclination, it is preferable to supply the washing water from the upper end of the trough. By supplying the wash water from the upper end of the trough, the flow rate of the wash water can be further increased.

The trough is installed at a position below the filter cloth of the pressure filtration unit PF so that the side leak dropped from the side end of the filter cloth is collected in the trough.
Further, it is preferable to arrange the trough so that the side leak directly drops into the flow of cleaning water formed in the trough so that the side leak having high viscosity does not adhere to the trough.

  Further, it is preferable that the trough is installed below the high pressure part of the pressure filtration part PF (the pressure of the pressure filtration part PF will be described later). High-viscosity side leaks occur in the high-pressure portion, so that the side leaks are easily accumulated. The effect of the present invention is particularly exerted by providing the trough below the high pressure portion. Here, the high-pressure part of the pressure filtering part PF refers to a pressure filtering part composed of a third pressure roller or more in the traveling direction among the plurality of pressure rollers 4 constituting the pressure filtering part PF. .

  Further, when the trough is installed at an inclination, it is preferable that the lower end side of the trough is installed toward the high pressure part of the pressure filtration part PF. Since the flow of washing water becomes faster on the lower end side of the trough, install the lower end of the trough toward the high-pressure part where high-viscosity side leak is likely to occur, and the high-viscosity side leak will clog the trough. Can be suppressed.

  In the belt dewatering machine 1a of the first embodiment, the lower ends of the two troughs arranged on both sides of the filter cloth are respectively connected to the drainage channel 11, and the drainage channel 11 has one drainage port. It is inclined so that the washing water flows down toward 12. By providing the drain port, the side leak washed away by the wash water can be discharged to the outside of the machine. Further, by providing the drainage flow path, it is not necessary to provide drainage ports for the troughs on both sides, so that the cleaning water recovery work outside the machine becomes easy.

  Next, the gravity filtration section GF and the pressure filtration section PF of the belt dehydrator 1a of the first embodiment will be described in detail, but the structures of the gravity filtration section GF and the pressure filtration section PF are not limited thereto. Absent.

  The belt dehydrator 1a according to the first embodiment includes a gravity filtering unit GF that performs a filtering process by gravity, and a pressure filtering unit PF that pressurizes an object to be processed while sandwiching the upper filter cloth 2a and the lower filter cloth 2b. ing. The gravity filter GF is formed in a region of the upper filter cloth 2a that is installed substantially horizontally and concentrates the object to be processed. The gravity filtering unit GF is appropriately installed according to the state of the object to be processed provided to the pressure filtering unit PF when the amount of water in the object is large.

  In the pressure filtration unit PF, the upper filter cloth 2a and the lower filter cloth 2b sandwich the object to be processed, pass through the plurality of pressure rollers 4 in a meandering manner, and are concentrated in the gravity filter GF. Items are dewatered under pressure. As shown in the belt dehydrator 1a of the first embodiment, the plurality of pressure rollers 4 are preferably arranged so that the diameters of the rollers gradually decrease. When passing through a pressure roller having a small roller diameter, the pressure is stronger than when passing through a pressure roller having a large roller diameter. Therefore, when the roller diameters of the pressure roller are arranged so as to be sequentially reduced, the pressure is gradually and strongly increased as the two filter cloths progress, and good dewatering treatment can be performed while suppressing the occurrence of side leak. it can.

  For example, a method of dehydrating the coagulated sludge generated in the sewage treatment plant using the first belt dewatering machine 1a will be described. The coagulated sludge is fed to the upstream part of the horizontal region of the upper filter cloth 2a. The coagulated sludge is separated into concentrated sludge and filtrate when passing through the gravity filtration section. Next, the concentrated sludge is provided between the upper filter cloth 2a and the lower filter cloth 2b, and passes through the plurality of pressure rollers 4 in a zigzag manner. While passing through the pressure roller 4, the concentrated sludge is pressure-dewatered to obtain a dehydrated cake. The dehydrated cake is scraped off by the scraper 5 and discharged to the outside of the machine.

  Here, the filtrate separated by the gravity filter GF is collected in the filtrate receiver 7 and sent to the water collecting region W of the drain pan 9a. The filtrate generated by the dehydration process of the pressure filtration unit PF drops into the drain pan 9a installed at the bottom of the belt dehydrator 1a, and then flows into the troughs 10 formed on both side surfaces of the drain pan 9a. , Is discharged out of the machine along with the wash water.

  After the dehydrated cake is scraped off, the upper filter cloth 2a and the lower filter cloth 2b are washed by the filter cloth washing sprays 6a and 6b, respectively. The filter cloth cleaning drainage generated when the upper filter cloth 2a is cleaned is collected by the filter cloth cleaning drainage receiver 8 and sent to the water collecting region W of the drain pan 9a. On the other hand, the cleaning drainage of the lower filter cloth 2b is configured to drop into the water collecting area W because the filter cloth cleaning spray 6b is installed above the water collecting area W. Then, the filtrate and filter cloth cleaning wastewater that have been put into the water collecting region W are supplied to the trough 10 as cleaning water.

  The belt dehydrator of the present invention can be configured without providing the filtrate receiver 7 and the filter cloth cleaning / drainage receiver 8 by appropriately changing the positions of the gravity filter GF and the filter cloth cleaning sprays 6a and 6b. is there.

[Second Embodiment]
5 to 7 are schematic explanatory views showing the structure of the belt dehydrator 1b according to the second embodiment of the present invention.
The belt dehydrator 1b of the second embodiment is provided with a triangular trough 10c (see the front view of FIG. 6). The trough 10c is formed by a structure in which the central portion of the bottom surface of the drain pan 9b is raised in a mountain shape from the front surface to the back surface, and the drain pan 9b is installed so as to be inclined as a whole.
The gravity filtration unit GF and the pressure filtration unit PF installed on the upper portion of the second belt dehydrator 1b are configured by different endless belts, and the gravity filtration unit GF is disposed on the upper side of the inclined drain pan 9b. The pressure filtration unit PF is arranged on the lower side of the inclined drain pan 9b.

  The filtrate filtrated in the gravity filtration unit GF and the pressure filtration unit PF is collected in the drain pan 9b and flows down to both side faces of the drain pan 9b along the bottom surface of the drain pan 9b protruding in a mountain shape. Then, the washing water flows down along both side surfaces of the inclined drain pan 9b.

  Further, the filter cloth cleaning drainage generated when cleaning the upper filter cloth 2c is collected in the filter cloth cleaning drainage receiver 8 and sent to the trough 10c for use as cleaning water. After cleaning the lower filter cloth 2d, the filter cloth cleaning wastewater of the lower filter cloth 2d falls on the drain pan 9b and flows into the trough 10c like the filtrate.

  Further, a purified water inlet 14 is provided in the vicinity of both side surfaces of the upper end (rear side) of the drain pan 9b (see FIG. 7). A purified water line and a pump are connected to the purified water inlet 14, and the power of the pump can be used to inject the purified water into the trough 10c. The injection of purified water is supplementarily performed when the side leak does not flow out due to the drainage of the filtrate and filter cloth.

  The drainage ports 12 are provided in the vicinity of both side surfaces of the lower end portion (front side) of the drain pan 9b, respectively, and discharge the wash water flowing down the trough 10c.

  As described above, the cleaning water supply means of the second embodiment is configured to supply the filtrate and the filter cloth cleaning drainage as cleaning water from the lateral direction of the trough 10c. Although the flow of the wash water is lower than that when the wash water is supplied from the upper end of the trough, it is not necessary to collect the wash water at the upper end of the trough, and the structure can be simplified.

  Further, in the second embodiment, an auxiliary cleaning water supply means is provided by the purified water inlet 14, the water purification line and the pump. As a result, when the trough is clogged with high-viscosity side leak, purified water can be supplied by the pump. The supplied purified water can be accelerated by gravity in addition to acceleration by pump power to form a strong flow.

The belt dehydrator of the present invention is a water treatment plant such as a sewage treatment plant or a water purification plant, sludge generated in a metal plating plant, a paper manufacturing plant, etc. Can be used in the dehydration treatment of.
It can also be used for the concentration of solids in pharmaceutical factories, food factories and the like.

1a, 1b belt dehydrator, 2a, 2c, upper filter cloth, 2b, 2d lower filter cloth, 3 support roller, 4 pressure roller, 5 scraper, 6a, 6b filter cloth cleaning spray, 7 filtrate receiving, 8 filter cloth cleaning Drainage receiver, 9a, 9b drain pan, 10, 10a, 10b, 10c, 10d, 10e trough, 11 drainage channel, 12 drainage port, 13 weir, 14 clean water inlet, 15 gutter, 16 wall, GF gravity filter, PF Pressure filtration section, W water collection area

Claims (3)

In a belt dehydrator that filters an object to be processed using an endless belt-shaped filter cloth,
A drain pan into which the side leak that has flowed out from the side end of the filter cloth falls,
Cleaning water supply means for supplying cleaning water for cleaning the side leak that has fallen into the drain pan,
The drain pan is provided with a trough at a position where the side leak falls,
The belt dewatering machine is characterized in that the trough is inclined so as to be lowered only in a direction in which an object to be processed filtered by a filter cloth is discharged, and is disposed below a high pressure part of a pressure filtration part. The belt dewatering machine according to claim 1 , wherein the cleaning water includes a filtrate that has passed through the filter cloth, and filter cloth cleaning drainage for cleaning the filter cloth. The belt according to claim 1 or 2 , wherein the troughs are respectively arranged on both sides of the filter cloth so that side leaks flowing out from both end portions of the filter cloth fall into the trough. Dehydrator.

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