JP4930667B2 - Screw press sludge dewatering equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a screw press-type sludge dewatering device that is particularly excellent in dewatering efficiency and that eliminates the need for cleaning the filtration surface by preventing sludge from adhering to or clogging the filtration surface.
[0002]
[Prior art]
Prior to the disposal and incineration of various sludges, sludge dewatering is performed. As a sludge dewatering device used for such sludge dewatering, there is a screw press type sludge dewatering device. This type of screw press-type sludge dewatering device is introduced (mud supply) into an annular space between a cylindrical body and an inner cylinder that are concentric with each other, as described in, for example, Japanese Patent No. 2512683. Dehydration is performed while the mixture of sludge (suspension and solid components) and water (clear water) (water to be dehydrated, hereinafter referred to as “sludge mixture”) is transported toward the discharge port by the rotation of the spiral screw. Is. That is, the screw press-type sludge dewatering device rotationally drives a helical screw provided on the outer peripheral surface of the inner cylinder to squeeze and dewater the sludge mixture, and this dehydrated water (filtrate) is drained on the inner cylinder or cylinder ( On the other hand, the dewatered sludge (dehydrated matter) is discharged from the sludge discharge port.
[0003]
Such a conventional screw press type sludge dewatering device is often arranged horizontally as shown in FIG. 4, and the sludge mixture 2 introduced from the inlet 1 is disposed between the cylindrical body 3 and the shaft body 4. The sludge mixture 2 gathers below the annular space 5 and moves away from the filtration surface 6 above the annular space 5. If it does so, since the filtration surface 6 will no longer be used effectively, dewatering efficiency will fall. Furthermore, since the sludge mixture 2 transferred toward the discharge port gradually increases the concentration of sludge and becomes a cake-like dehydrated product, the moisture is reduced near the cake discharge port 7 (cake outlet), It accumulates on the filtration surface and easily causes clogging. When sludge is accumulated or clogged, the dewatering efficiency of the dewatering device is lowered. Therefore, in order to maintain the dewatering efficiency, for example, the deposit on the filtration surface needs to be washed with washing water.
[0004]
By the way, the discharge of the filtrate in the screw press type sludge dewatering device is performed by the filtration pressure which is the difference between the pressure of the sludge mixture near the filtration surface and the pressure of the dehydrated filtrate. And the water | moisture content of a sludge mixture is dehydrated rapidly, so that this filtration pressure is high. However, if the filtration pressure becomes too high, even the sludge adheres (deposits) or clogs on the filtration surface in an attempt to pass through the filtration surface, and further passes (leaks). On the other hand, the higher the sludge concentration of the sludge mixture, the higher the filtration pressure must be set.
[0005]
Therefore, as shown in FIG. 5, the cylindrical body 3 and the shaft body 4 that are concentric with each other are arranged vertically, and the insertion port 1 is disposed above the cake discharge port 7 in the height direction of the dehydrator. A screw press-type dehydrator can be considered. In such a screw press-type dewatering device, the sludge mixture 2 is uniformly distributed in the circumferential direction in the annular space 5 between the cylinder 3 and the shaft body 4 and fills the inside of the annular space 5, and the filtrate is the filtrate. Since the surface 6 flows down toward the filtrate discharge port 8, the filtration surface 6 of the cylindrical body 3 is effectively used for dewatering, and the dewatering efficiency is improved.
[0006]
Moreover, since the water depth of the sludge mixture 2 filled in the annular space 5 is shallow on the input port 1 side, the filtration pressure applied to the filtration surface 6 is low, while the water depth is increased on the cake discharge port 7 side. The filtration pressure increases. Therefore, the filtration pressure is low on the inlet 1 side where the sludge concentration is low, the filtration pressure is high on the cake discharge port 7 side where the sludge concentration is high, and the filtration pressure becomes the sludge concentration of the sludge mixture 2 filled in the annular space 5. It will be a response. Therefore, clogging of the filtration surface 6 can be made difficult to occur.
[0007]
[Problems to be solved by the invention]
By the way, the optimization of the filtration pressure, in which sludge does not adhere to or clog the filtration surface and does not leak the filtration surface, and only water is efficiently discharged from the sludge mixture, is the pressure inside the filtration surface filled with the sludge mixture. This is done by setting the difference from the pressure outside the filtration surface.
In the screw press-type sludge dewatering device shown in FIG. 5, the pressure inside the filtration surface 6 can be set by the pressure due to the water depth of the sludge mixture 2 in the annular space 5 or the squeezing of the sludge mixture by the spiral screw 9. However, since the filtrate dehydrated on the filtration surface 6 flows down toward the filtrate discharge port 8, the pressure outside the filtration surface 6 cannot be set. Therefore, it is difficult to set the optimum filtration pressure according to the sludge concentration.
[0008]
The present invention has been made in order to solve the above-mentioned problems, and it is possible to improve the dewatering efficiency by effectively utilizing the filtration surface of the cylindrical body for dewatering, and to easily set the optimum filtration pressure. It is an object of the present invention to provide a screw press type sludge dewatering device capable of improving the dewatering efficiency while preventing sludge adhesion, clogging, and leakage.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, according to the present invention, in claim 1, a cylindrical body having a shaft body disposed concentrically therein and provided substantially vertically and a peripheral wall of the cylindrical body are formed. A filtering surface provided at the upper end of the cylindrical body, an inlet for introducing a sludge mixture into an annular space formed between the cylindrical body and the shaft body, and an outer periphery of the shaft body A screw container which is spirally provided on the surface and is driven to rotate and transports the sludge mixture charged into the annular space downward, and the filtrate filtrated to the outside of the cylindrical body through the filtration surface And a filtrate discharge port provided at the lower end of the filtrate container, and the filtrate is connected to the filtrate discharge port to discharge the filtrate to the outside, and the discharge height position of the filtrate is provided to be adjustable. A filtrate discharge section for submerging the filtration surface with the filtrate contained in the container; The cylindrical body a screw press sludge dewatering apparatus and a dehydrated product discharge outlet for discharging are provided at the lower end dehydrate from said annular space is provided.
[0010]
In the screw press-type sludge dewatering device configured as described above, the filtration surface is in a state of being submerged in the filtrate container containing the filtrate. Therefore, it is possible to improve the dehydration efficiency by effectively using the entire filtration surface, and by adjusting the height of the filtrate outlet for discharging the filtrate of the filtrate container, the filtration surface provided as the peripheral wall of the cylinder The pressure difference between the inside (annular space side) and the outside of the filtration surface (filtrate container side) can be adjusted.
[0011]
That is, the filtration pressure can be optimized by adjusting the height of the filtrate outlet in consideration of the pressure (for example, natural downstream pressure) at which the sludge mixture is introduced into the annular space. Thus, if the filtration pressure is optimized, dewatering efficiency can be improved while preventing sludge from adhering to the filtration surface, clogging, and further leaking. Even if the filtration pressure is optimized, a very small amount of sludge may leak the filtration surface, but such a small amount of sludge settles toward the lower end of the filtrate container, and this lower end The filtrate is discharged together with the filtrate flow from the filtrate discharge port provided in.
[0012]
In Claim 2, the partition which further divides | segments the space between the said filtrate container and the said cylinder into a some space in a height direction, and the filtrate each provided in the lower end part of each said space divided | segmented by this partition There is provided a screw press type sludge dewatering device provided with a discharge port and a filtrate discharge unit connected to each of the filtrate discharge ports and discharging the filtrate to the outside while filling each of the spaces with the filtrate.
[0013]
In the screw press-type sludge dewatering device configured as described above, the space between the filtrate container for storing the filtrate discharged from the filtration surface and the cylinder is divided into a plurality in the height direction. And the filtration pressure in the filtration surface which faced the space divided | segmented into plurality can be adjusted by adjusting the height of the filtrate discharge | emission part for every space divided | segmented into plurality. Accordingly, the sludge mixture introduced into the annular space corresponds to increasing the sludge concentration while being transferred downward from the upper end of the annular space, that is, the position of the filtration surface in the water depth (water depth in the annular space) direction. The filtration pressure can be optimized over the entire filtration surface, and the amount of sludge on the filtration surface can be reduced compared to the case where the space between the filtrate container and the cylinder is not divided. Dehydration efficiency can be further improved while further preventing adhesion, clogging, and leakage.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a screw press type sludge dewatering apparatus (hereinafter referred to as “sludge dewatering apparatus”) according to an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 shows a first embodiment of a sludge dewatering apparatus according to the present invention.
The sludge dewatering device 10 includes a cylindrical body 11 arranged vertically on a base (not shown) and a shaft body 12 arranged concentrically on the cylindrical body 11. The upper rotating shaft 13 of the shaft body 12 is connected at its upper end to a motor 14 via a speed reducer (not shown), and the lower end rotating shaft 15 of the shaft body 12 is rotatably supported by a bearing 16. Yes. A spiral screw 17 is provided on the outer peripheral surface 12 a of the shaft body 12. The spiral screw 17 is disposed in an annular space 18 between the cylinder body 11 and the shaft body 12, and the shaft body 12 is moved by the motor 14. When driven to rotate, it rotates integrally with the shaft body 12.
[0015]
At the upper end of the cylindrical body 11, a charging port 19 that communicates with the annular space 18 is provided, and this charging port 19 communicates with the aggregation tank 21 through a pipe 20. An agitation blade 23 that is rotationally driven by an agitation motor 22 is disposed inside the agglomeration tank 21 so that the concentrated sludge and the aggregating agent supplied to the agglomeration tank 21 are agitated and mixed. The sludge mixture in the agglomeration tank 21 has a water surface height (h1), and is fed as a material to be dehydrated into the annular space 18 via the inlet 19 of the sludge dewatering apparatus 10 by natural downstream.
[0016]
The sludge dewatering device 10 has a filtrate container 24 arranged concentrically around the cylinder 11, and the filtrate container 24 is disposed between the drainage screen 11 d of the cylinder 11. A filtrate passage 25 (annular passage) is formed, and the filtrate filtered by the discharge screen 11d is accommodated. A filtrate outlet 26 is provided in the peripheral wall of the lower end portion of the filtrate container 24, and a filtrate pipe 27 is connected to the filtrate outlet 26. The filtrate pipe 27 slightly extends in a substantially horizontal direction from the filtrate discharge port 26 and then rises upward, and a substantially tubular filtrate discharge portion 28 is connected to the filtrate pipe 27 at the raised tip portion. On the other hand, the height can be adjusted up and down. Further, the upper end portion of the filtrate discharge portion 28 is open, and the drain 29 extends in a horizontal direction slightly below the upper end portion of the filtrate discharge portion 28 to discharge the filtrate to the outside of the sludge dewatering device 10. It is like that. Here, the water level of the drainage surface of the filtrate in the drain 29 is the height (h2).
[0017]
The lower end portion of the shaft body 12 extends downward through the central opening of the lower wall 11c of the cylindrical body 11, and a blocking plate 12b that substantially closes the lower end surface of the annular space 18 on the lower end surface of the shaft body 12. Is fixed. A gap 30 is formed between the blocking plate 12b and the lower wall 11c of the cylinder 11. The sludge dehydrated in the annular space 18 is discharged from the gap 30 to the outside of the sludge dewatering device through the central opening of the lower wall 11c. Thus, the gap 30 has a role of a sludge discharge port (cake discharge port).
[0018]
Here, the external appearance of the cylinder 11 is shown in FIG. The cylindrical body 11 has a peripheral wall 11a, an upper wall 11b through which the shaft body 12 is inserted, and an annular lower wall 11c extending radially inward from the lower end of the peripheral wall 11a. Here, the upper wall 11 b closes the upper side of the cylindrical body 11 together with the shaft body 12. Further, the peripheral wall 11a is made of, for example, a punching metal except for its upper end and lower end, and this punching metal has a number of holes to form a drainage screen 11d (filter surface).
[0019]
In the sludge dewatering device 10 configured as described above, the sludge mixture is charged into the annular space 18 from the coagulation tank 21. Then, since the sludge dewatering device 10 and the annular space 18 are arranged vertically, and the inlet 19 is provided at the uppermost position of the annular space 18, the sludge mixture is rotated with the shaft body 12. 17 is transferred downward in the annular space 18. Then, the sludge mixture is uniformly distributed in the circumferential direction in the annular space 18 due to the action of gravity.
[0020]
By the way, when the sludge mixture is filled in the annular space 18, the filtrate is discharged from the discharge screen 11 d of the cylindrical body 11 and stored in the filtrate container 24. The filtrate stored in the filtrate container 24 flows to the drain 29 through the filtrate outlet 26, the filtrate pipe 27 and the filtrate outlet 28, and is discharged from the drain 29 to the outside of the sludge dewatering device 10. Here, the water level (h2) of the discharge surface of the filtrate in the drain 29 is a height at which the discharge screen 11d is submerged in the filtrate.
[0021]
As described above, the filtration pressure of the discharge screen 11d submerged in the filtrate is determined by the pressure difference between the inside and the outside of the discharge screen 11d. And the water level (h1) of the coagulation tank 21 which introduces the sludge mixture into the annular space 18 through the inlet 19 naturally downstream is at a position higher than the water level (h2) of the discharge surface of the filtrate.
Then, the filtration pressure in the discharge screen 11d is set by the difference (dh = h1-h2) between the water level (h1) of the coagulation tank 21 and the water level (h2) of the discharge surface of the filtrate. That is, by adjusting the height of the filtrate discharge portion 28 with respect to the filtrate pipe 27, the filtration pressure in the discharge screen 11d can be set to the optimum filtration pressure.
[0022]
Thus, when the optimum filtration pressure of the discharge screen 11d is set, the dewatering efficiency of the discharge screen 11d can be increased, and sludge adherence, clogging, and leakage can be prevented on the filtration surface.
The optimum filtration pressure depends on the strength (floc strength) of the sludge contained in the sludge mixture and the sludge concentration, but the water level (h1) of the coagulation tank 21 and the discharge of the filtrate in the drain 29 for setting the optimum filtration pressure. The water level difference (dh) from the surface water level (h2) is usually in the range of 20 mm to 100 mm.
[0023]
FIG. 3 shows a second embodiment of the sludge dewatering apparatus according to the present invention. In addition, about the component which has the function similar to 1st embodiment, the same code | symbol is attached | subjected and the description is abbreviate | omitted.
In the sludge dewatering device 40 shown in FIG. 3, in addition to the sludge dewatering device 10 according to the first embodiment, a filtrate passage formed between the filtrate container 24 and the cylinder 11 is separated by the partition walls 24 a and 24 b. The container 24 is divided into approximately three equal parts in the axial direction. A filtrate passage 25a is provided between the upper end of the filtrate container 24 and the partition wall 24a, a filtrate passage 25b is provided between the partition wall 24a and the partition wall 24b, and a filtrate passage 25c is provided between the partition wall 24b and the lower end of the filtrate container 24. , Each is formed.
[0024]
Further, a filtrate outlet 26a is provided on the peripheral wall of the filtrate container 24 at the lower end of the filtrate passage 25a, and a filtrate pipe 27a is connected to the filtrate outlet 26a. The filtrate pipe 27a extends slightly from the filtrate discharge port 27a in a substantially horizontal direction and then rises upward. A filtrate discharge portion 28a is connected to the leading end of the filtrate pipe 27a. The filtrate discharge portion 28a has a substantially tubular shape and can be adjusted in height up and down with respect to the filtrate pipe 27a. An upper end portion of the filtrate discharge portion 28a is open, and a drain 29a having an open end extends in a horizontal direction slightly below the upper end portion of the filtrate discharge portion 28a.
[0025]
Similarly, a filtrate outlet 26b is provided in the peripheral wall of the filtrate container 24 at the lower end of the filtrate passage 25b, a filtrate pipe 27b is connected, and a filtrate outlet 28b having a drain 29b is connected. Further, a filtrate discharge port 26c is provided on the peripheral wall of the filtrate container 24 at the lower end of the filtrate passage 25c, a filtrate pipe 27c is connected, and a filtrate discharge portion 28c having a drain 29c is connected.
[0026]
Then, by adjusting the height of the filtrate discharge part 28a, the water level (h2a) of the filtrate discharge surface in the drain 29a is adjusted, the filtrate passage 25a is filled with the filtrate, and the discharge screen 11d facing the filtrate passage 25a. To submerge in the filtrate. Further, the water level (h2a) of the drainage surface of the filtrate in the drain 29a is set to a position lower in the height direction than the water level (h1) of the coagulation tank 21. Further, the filtrate is discharged so that the water level (h2b) of the filtrate discharge surface in the drain 29b is lower than the water level (h2a) and the water level (h2c) of the filtrate discharge surface in the drain 29c is lower than the water level (h2b). The heights of the sections 28b and 28c are set, and the filtrate passages 25b and 25c are filled with the filtrate so that the discharge screen 11d facing the filtrate passage 25b and the discharge screen 11d facing the filtrate passage 25c are submerged in the filtrate. To.
[0027]
Then, the filtration pressure (Pa) of the portion where the discharge screen 11d faces the filtrate passage 25a is the difference between the water level (h1) of the coagulation tank 21 and the water level (h2a) of the drainage surface of the filtrate in the drain 29a (dha = h1− h2a).
Similarly, the filtration pressure (Pb) of the portion where the discharge screen 11d faces the filtrate passage 25b is the difference between the water level (h1) of the coagulation tank 21 and the water level (h2b) of the drainage surface of the filtrate in the drain 29b (dhb = h1). -H2b).
[0028]
Similarly, the filtration pressure (Pc) at the portion where the discharge screen 11d faces the filtrate passage 25c is the difference between the water level (h1) of the coagulation tank 21 and the water level (h2c) of the drainage surface of the filtrate in the drain 29c (dhc = h1). -H2c).
Here, since h2a>h2b> h2c, dhc>dhb> dha, and the relationship Pc>Pb> Pa is established.
[0029]
On the other hand, the sludge concentration of the sludge mixture transferred downward in the annular space 18 by the spiral screw 17 is dehydrated and becomes high concentration as it is transferred downward in the discharge screen 11d. Accordingly, the lower the discharge screen 11d, the higher the optimum filtration pressure must be.
In the sludge dewatering device 40, as described above, the filtration pressure can be adjusted corresponding to each discharge screen 11d portion facing each filtrate passage 25a to 25c. That is, in the sludge dewatering device 40, the filtration pressure can be increased toward the lower side of the discharge screen 11d where the sludge concentration becomes higher, and the filtration pressure can be optimized over the entire surface of the discharge screen 11d.
[0030]
In the second embodiment, the filtrate passage is divided into three parts, but it may be divided into two parts or more than four parts. This is because the number of divisions of the filtrate passage that can further optimize the filtration pressure across the entire height of the discharge screen varies depending on the sludge mixture to be dewatered and the shape and dimensions of the sludge dewatering device. .
Also, assuming that the sludge from the coagulation tank is fed into the sludge dewatering device in the natural downstream, the water level on the drainage surface of the filtrate at the drain is lower than the water level of the coagulation tank, but the sludge is pumped from the coagulation tank. When the pressure is applied to the sludge dewatering device, the water level of the discharge surface of the filtrate in the drain is set in consideration of the pressure generated inside the discharge screen by this pump.
[0031]
As described above, the present invention is not limited to the first and second embodiments described above, and can be implemented by being appropriately modified without departing from the spirit of the present invention.
[0032]
【Effect of the invention】
As described above, according to the screw press type sludge dewatering device of the present invention, the entire filtration surface for dewatering water from the sludge mixture is submerged in the filtrate. A screw that can improve the efficiency of dewatering while facilitating the setting of the optimum filtration pressure on the filtration surface, and preventing sludge from adhering, clogging, and leaking on the filtration surface. For a press sludge dewatering device, extremely important effects can be exhibited.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a schematic configuration of a main part of a first embodiment of a screw press sludge dewatering apparatus according to the present invention.
FIG. 2 is an external view of a cylindrical body having a filtration surface (discharge screen) of the screw press sludge dewatering device of FIG.
FIG. 3 is a cross-sectional view showing a schematic configuration of a main part of a second embodiment of the screw press sludge dewatering apparatus according to the present invention.
FIG. 4 is a schematic view showing a state of filling a sludge mixture in a conventional screw press sludge dewatering device arranged horizontally.
FIG. 5 is a schematic view showing a state of filling a sludge mixture in a vertically arranged screw press sludge dewatering device.
[Explanation of symbols]
10, 40 Screw-type sludge dewatering device 11 Tube 11d Discharge screen 12 Shaft body 12a Shaft body outer peripheral surface 17 Spiral screw 18 Annular space 19 Input port 24 Filtrate containers 24a, 24b Partition walls 25, 25a, 25b, 25c Filtrate passage 26, 26a, 26b, 26c Filtrate outlets 28, 28a, 28b, 28c Filtrate outlet 30 gap

Claims (2)

A cylindrical body provided with a shaft body arranged concentrically inside and provided substantially vertically;
A filtration surface provided as a peripheral wall of the cylindrical body;
An inlet for providing a sludge mixture into an annular space provided between the cylindrical body and the shaft body, provided at the upper end of the cylindrical body,
A screw which is spirally provided on the outer peripheral surface of the shaft body and is rotationally driven, and transfers the sludge mixture charged into the annular space downward;
A filtrate container containing the filtrate filtered to the outside of the cylindrical body through the filtration surface;
A filtrate outlet provided at the lower end of the filtrate container;
A filtrate discharge unit connected to the filtrate discharge port to discharge the filtrate to the outside, and to adjust the discharge height position of the filtrate and to submerge the filtration surface by the filtrate stored in the filtrate container; ,
A screw press-type sludge dewatering device provided with a dewatered material discharge port provided at a lower end portion of the cylindrical body for discharging dehydrated material from the annular space. In the screw press type sludge dewatering device according to claim 1,
Furthermore, a partition that divides the space between the filtrate container and the cylinder into a plurality of spaces in the height direction,
Filtrate outlets respectively provided at the lower end of each space divided by the partition;
A screw press type sludge dewatering device connected to each of the filtrate outlets, and having a filtrate outlet for discharging the filtrate to the outside while filling each of the spaces with the filtrate.

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