JP2011020080A - Apparatus for separating and dehydrating sewage sludge - Google Patents

Abstract

[PROBLEMS] To reduce the installation space, to have a water passing ability that is not easily affected by fluctuations in the concentration of the residue, to have a high residue recovery rate, and to have good residue dewatering performance. To provide a separation dehydrator.
A screw 2 is disposed inside a casing 1 having a cylindrical screen portion 11 drained from a peripheral surface and dehydrating back pressure portions 12 and 13 for applying back pressure. It is a residue separating and dewatering machine that contains water introduced into the inside and separates and dehydrates the screen, and the screen portion 11 of the casing 1 is composed of a wedge wire screen.
[Selection] Figure 1

Description

  The present invention relates to a screen residue separator and dehydrator, and more particularly to a screen residue separator and dewaterer that can reduce installation space.

  Conventionally, in order to separate and dewater debris (contaminants) contained in sewage, for example, as shown in FIG. 8, crushed debris and washing water are introduced into a transfer tank, and these are separated by a pressurized water pump. Water is drained by sending it to a bar screen type screen separator, and the drained residue is dehydrated with a screw press type screen dewatering machine and then discharged to a screen hopper.

By the way, this screen separation and dewatering system is composed of two devices, a screen residue separator and a screen dewatering device. Therefore, a large installation space is required, especially in a treatment plant where space is limited. It may be difficult to ensure the maintenance, and problems may arise in terms of maintenance.
In addition, the processing object of the residue separation and dewatering method is a residue that has been crushed and washed, and is not easily subject to clogging of the screen or insufficient dewatering, and is basically relatively easy to handle. Nevertheless, there are many cases in which a screw press type screen dewatering machine with large power is used, and there are problems such as bad effects caused by excessive squeezing, such as clogging of the discharge part of the screen dewatering machine. It was.

  Further, in order to solve these problems, particularly the problem of requiring a large installation space, it is possible to separate and dewater water-containing residue with one apparatus disclosed in Patent Document 1. Although the present inventors have proposed a residue separation and dehydrator, the present applicant has problems in terms of water passage capacity, residue collection rate, residue dewatering performance, and the like.

JP 2009-142723 A

  In view of the problems of the above-described conventional screen residue separator and dehydrator, the present invention can reduce the installation space and has a water passing ability that is not easily affected by the concentration variation of screen residue, and high screen residue recovery. An object of the present invention is to provide a residue separation and dehydrator having a high rate and good residue dewatering performance.

  In order to achieve the above-mentioned object, the residue separating and dewatering machine of the present invention includes a cylindrical screen portion drained from a peripheral surface and a casing having a dewatering back pressure portion for applying and dehydrating back pressure. A screw is arranged inside, and the residue containing water introduced into the casing is separated and dehydrated, and the residue separation and dehydrator is configured such that the screen portion of the casing is constituted by a wedge wire screen. It is characterized by that.

  In this case, the dehydrating back pressure portion of the casing can be formed in a conical shape whose cross-sectional area gradually decreases.

  In addition, the rotational drive mechanism of the casing and the screw is arranged opposite to each other on the bevel pinion driven by the electric motor, and the two bevel gears respectively connected to the casing and the screw are engaged with each other so as to rotate in reverse with each other. can do.

  In addition, the screw shaft of the screw is hollow, forms a discharge port that opens in the casing, and includes water supplied from a supply port formed on the opposite side of the casing and the screw rotational drive mechanism. The residue can be introduced into the casing through the discharge port.

  According to the residue separation and dehydrator of the present invention, a screw is disposed inside a casing having a cylindrical screen portion that is drained from the peripheral surface and a dehydration back pressure portion for applying and dehydrating back pressure. And a separator separating and dewatering machine that contains water introduced into the casing and separates and dehydrates the residue, and the screen part of the casing is constituted by a wedge wire screen. It has the ability to pass water that is not easily affected by fluctuations in the concentration of slag, has a high scum recovery rate, and has good slag dewatering performance. Combined with being able to separate and dewater the wastewater, the installation space can be reduced and a residue separation and dehydrator can be provided.

  In addition, by forming the dehydration back pressure part of the casing into a conical shape with a gradually decreasing cross-sectional area, it is possible to apply a uniform back pressure to the residue and prevent the dehydration back pressure part from clogging the residue. can do.

  In addition, the rotational drive mechanism of the casing and the screw is arranged opposite to each other on the bevel pinion driven by the electric motor, and the two bevel gears respectively connected to the casing and the screw are engaged with each other so as to rotate in reverse with each other. As a result, the rotary drive mechanism for the casing and the screw can be reduced in size, and both can be rotated in reverse at an appropriate speed.

  In addition, the screw shaft of the screw is hollow, forms a discharge port that opens in the casing, and includes water supplied from a supply port formed on the opposite side of the casing and the screw rotational drive mechanism. By introducing the debris into the casing through the discharge port, the supply of debris including water into the casing can be reliably and without affecting the structure of the casing and screw rotation drive mechanism. It can be done smoothly.

It is sectional drawing which shows one Example of the residue separation dehydrator of this invention. It is a schematic explanatory drawing of the residue separation dehydration system by the same residue separation dehydrator. It is explanatory drawing of effective angle (theta) shown by the cross section of a screen. It is explanatory drawing which shows the relationship between actual load flow volume and effective angle (theta). It is explanatory drawing which shows the relationship between the density | concentration of an inflow residue, and the effective angle (theta). It is explanatory drawing which shows a residue collection rate. It is explanatory drawing which shows the relationship between a press pressure and the moisture content of dewatering residue. It is a schematic explanatory drawing of the conventional residue separation dehydration system.

  Hereinafter, embodiments of the residue separating and dehydrating machine of the present invention will be described with reference to the drawings.

FIG. 1 shows an embodiment of a residue separation dehydrator according to the present invention.
The residue separating and dewatering machine A includes a cylindrical screen portion 11 that is drained from the peripheral surface, and dehydrating back pressure portions 12 and 13 for applying back pressure to dehydrate the main body casing K. The casing 1 is disposed, and the screw 2 is disposed inside the casing 1. As shown in FIG. 2, crushed residue and washing water are introduced into the transfer tank, and these are separated by a pressurized water pump. By pumping into the casing 1 of the dehydrator A, the residue containing water introduced into the casing 1 is separated and dehydrated, and then discharged to a residue hopper.

  In this case, the casing 1 and the screw 2 are configured to rotate reversely to each other by a rotation drive mechanism D including an electric motor M or the like.

  The main body casing K is preferably structured so as to be sealed in a state in which the casing 1 is accommodated so that the sewage to be treated does not scatter to the surroundings, and the casing 1 is inclined gently so that the horizontal or non-driving side is lowered. Thus, the casing 1 is clogged as it is rotatably arranged and the cleaning nozzle N is disposed above the casing 1 to inject the cleaning water toward the outer peripheral surface of the casing 1. Washing is performed so that there is no discharge, and a drain outlet Ka for discharging the washed water after washing and the water solid-liquid separated in the casing 1 is formed.

The screen portion 11 of the casing 1 is constituted by a wedge wire screen.
This wedge wire screen is formed by arranging deformed wires 11a such as stainless steel having an inverted triangular or inverted trapezoidal cross section in parallel at equal intervals to form eyes (slits). Are arranged side by side in the axial direction of the casing 1 so that the bottom side of the inverted triangle or inverted trapezoid of the deformed wire 11a is positioned on the inner surface side of the screen portion 11, and the rear surface (the outer surface of the screen portion 11). The support member 11b extends in the axial direction of the casing 1 on the side).
In addition, the structure of the screen part 11 is not limited to this, The wedge wire screen formed by extending the deformed wire 11a in the axial direction of the casing 1 can also be used.
Due to its structure, the wedge wire screen is tough, highly accurate, hardly clogged, has high dewaterability, and the screen surface is smooth, so that the processed product and residue can be moved smoothly. The cleaning effect is high, and maintenance is easy. In particular, it has an advantage that a narrow slit, for example, a slit of about 2 mm, or a smaller slit can be formed with high accuracy.

  The dehydrating back pressure portions 12 and 13 of the casing 1 are for dehydrating by adding back pressure to the residue containing water introduced into the screen portion 11 in the casing 1, and the sectional area gradually decreases. It is formed in a conical shape, and in the present embodiment, it is composed of a conical portion 12 made of a punching metal such as stainless steel and a cylindrical portion 13 connected to the conical portion 12.

The end portions of the dehydration back pressure portions 12 and 13, that is, the end portions of the cylindrical portion 13 can be left open as they are to form a residue discharge port. On the other hand, a resistance plate 3 having a circular opening for applying a back pressure (a residue outlet) is provided.
The opening diameter of the resistance plate 3 can be set as appropriate according to the properties of the residue.

Then, by constructing the casing 1 so that the screen portion 11 and the dehydration back pressure portions 12 and 13 are continuously connected to each other, the residue containing water is separated by one device (the residue separation and dehydrator A). It can be dehydrated.
The casing 1 is rotatably supported by the bearing 7 and the main body casing K on the rotational drive mechanism D side.

The screw 2 is configured by disposing screw blades 22 that turn around the outer periphery of a screw shaft 21 having a hollow inside.
The pitch of the screw blades 22 may be uniform over the entire length of the screw shaft 21 or may be different between the screen portion 11 and the dehydrating back pressure portions 12 and 13.
In this embodiment, the end portion of the screw blade 22 is formed so as to face the cylindrical portion 13 of the dehydrating back pressure portions 12 and 13 so that the residue can be discharged reliably.
Further, the screw shaft 21 forms a discharge port 23 that opens into the casing 1 (more specifically, the screen portion 11), and from a supply port 24 that is formed on the side opposite to the side where the rotation drive mechanism D is disposed. Sediment containing the supplied water can be introduced into the casing 1 through the discharge port 23.
Thereby, without affecting the structure of the rotational drive mechanism D, the supply of the residue including water into the casing 1 can be reliably and smoothly performed.

The rotational drive mechanism D that rotates the casing 1 and the screw 2 in the opposite directions is disposed opposite to the bevel pinion 4 that is driven by the electric motor M, and is connected to the casing 1 and the screw 2 respectively. 6 is connected to the base end portion of the casing 1 through a cylindrical connecting shaft member 8 rotatably supported by a bearing 7, and a bevel gear for driving a screw. 6 is connected to the base end portion of the screw shaft 21 via a cylindrical screw shaft coupling member 9.
The screw shaft connecting member 9 is inserted so as to penetrate the connecting shaft member 8 of the casing 1 and is rotatably supported in the connecting shaft member 8 via a bearing 10.

Next, the operation of the residue separation dehydrator will be described.
When the bevel pinion 4 is rotationally driven by driving the electric motor M, the bevel gear 5 for driving the casing and the bevel gear 6 for driving the screw that are meshed with the bevel pinion 4 are both driven, and the casing 1 and the screw 2 are rotated in reverse directions. To do.
In this case, since the two bevel gears 5 and 6 are meshed with each other so as to rotate in opposite directions with respect to the bevel pinion 4 in one rotation drive mechanism D, the bevel pinion 4 is connected to the casing 1 and the screw 2. The rotation of the bevel gears 5, 6 and the casing 1 or the screw 2 can be performed simply by rotationally driving, and the connection between the casing 1 or the screw 2 can be achieved by using a cylindrical connecting shaft member 8 or a screw shaft connecting member 9 inserted into the connecting shaft member 8. It can carry out without impairing the intensity | strength of a member.

In this state, the residue including water supplied from the supply port 24 formed on the side opposite to the side where the rotational drive mechanism D of the screw shaft 21 is disposed is collected in the casing 1 (more specifically, the screen portion 11). By introducing into the casing 1 from the discharge port 23 of the screw shaft 21 that opens to the center, solid-liquid separation is promoted due to the synergistic action effect of the casing 1 and the screw 2 and is introduced into the casing 1. Water can be separated from the residue containing water.
The water solid-liquid separated in the casing 1 is discharged from the drain port Ka of the main body casing K together with the cleaning water from the cleaning nozzle N.

In addition, the residue, which is a solid component separated by solid-liquid separation in the screen portion 11 and the dehydration back pressure portions 12 and 13 of the casing 1, is transferred by the screw 2 that rotates in reverse to the casing 1, and the opening ( It is reliably and stably discharged to the outside from the residue discharge port).
Discharged.

Next, the characteristics of the above residue separation and dehydrator A will be described based on the test results.
Since the wedge wire screen constituting the screen portion 11 of the casing 1 of the screen separator dewatering machine A has a characteristic cross-sectional structure, water drainage is good and clogged objects are easily flowed to the outside. Resistant to residue concentration fluctuations.
FIG. 4 shows the relationship between the flow rate and the effective angle (effective sectional area relating to the water flow through the cylindrical screen, and FIG. 3 shows an explanatory diagram) in fresh water and actual load, and FIG. 5 shows the relationship between the residue concentration and the effective angle. .
As is clear from this result, it is understood that there is almost no difference between the fresh water and the actual load hydraulic state by adopting the wedge wire screen, and that the effective angle does not change drastically due to the increase in concentration. . That is, it is shown that the screen structure is less susceptible to the influence of density fluctuation, and the screen area can be greatly reduced, that is, the apparatus can be miniaturized.

Next, when examining the residue collection rate, the mesh width of the conventional residue separator is often 3 mm.
On the other hand, the wedge wire screen constituting the screen portion 11 of the casing 1 of the residue separating and dewatering machine A can set the mesh width to about 2 mm or even smaller than that due to the water flow effect. . Incidentally, the above-mentioned water flow performance data is for a mesh width of 2 mm.
The residue collection rate (capture rate) in this case is shown in FIG. Here, the horizontal axis indicates the passage flow velocity, and in this embodiment, it is used within the range of the maximum passage flow velocity of 0.4 m / s or less.
The average screen recovery rate of conventional bar screen screens (3 mm wide) was 90% on average, whereas the results shown in FIG. 6 show the screen residue recovery rate for the wedge wire screen of screen separator dehydrator A. Was 90% or more, and the residue collection rate was confirmed to be equal to or higher than the conventional one.

Next, when examining the dewatering performance of the residue, it is common for a conventional screw press to apply a strong back pressure by a hydraulic unit. However, in a residue that has been crushed and washed, The result that the press so far is unnecessary is obtained.
FIG. 7 shows the relationship between the press pressure and the water content of dewatered residue. Incidentally, the press pressure in the conventional case shows such a value that the numerical value on the horizontal axis in FIG. 7 is increased by one digit, and this excessive power is a major cause of the increase in power of the screw press.
According to the residue separating and dewatering machine A, it was confirmed that the dewatering was performed at a press pressure of about 0.04 MPa, and the moisture content of the residue was able to be substantially less than 70%.

  As mentioned above, although the residue separation dehydrator of this invention was demonstrated based on the Example, this invention is not limited to the structure described in the said Example, The structure suitably in the range which does not deviate from the meaning. Can be changed.

  The screen residue separator / dehydrator of the present invention can reduce the installation space, has a water passage capacity that is not easily affected by the concentration variation of screen residue, has a high screen residue recovery rate, and is not good. Since it has residue dewatering performance, it can be suitably used for the purpose of residue separation and dehydration in facilities with only a small installation space, and can also be used for the purpose of widely used residue separation and dehydration.

A Screen residue separation dehydrator D Rotation drive mechanism K Main body casing M Electric motor N Washing nozzle 1 Casing 11 Screen portion 11a Deformed wire 11b Support member 12 Conical portion (dehydration back pressure portion)
13 Cylindrical part (dehydration back pressure part)
2 Screw 21 Screw shaft 22 Screw blade 23 Discharge port 24 Supply port 3 Resistance plate 4 Bevel pinion 5 Bevel gear for driving the casing 6 Bevel gear for driving the screw 7 Bearing 8 Connecting shaft member 9 Screw shaft connecting member 10 Bearing

Claims (4)

  A cylindrical screen portion drained from the peripheral surface and a screw provided inside the casing having a dehydrating back pressure portion for applying and dehydrating back pressure, and water introduced into the casing are included. A residue separating and dewatering machine for separating and dewatering residue, wherein the screen portion of the casing is constituted by a wedge wire screen.   2. The residue separating and dewatering machine according to claim 1, wherein the dehydrating back pressure portion of the casing is formed in a conical shape in which a cross-sectional area gradually decreases.   The rotation drive mechanism of the casing and the screw is arranged opposite to each other on the bevel pinion driven by the electric motor, and the two bevel gears respectively connected to the casing and the screw are engaged with each other so as to rotate in reverse with each other. The residue separating and dewatering machine according to claim 1 or 2. The screw shaft of the screw has a hollow shape and forms a discharge port that opens in the casing, and includes water supplied from a supply port formed on the opposite side of the casing and the rotational drive mechanism of the screw. The residue separating and dewatering machine according to claim 1, 2 or 3, wherein the water is introduced into the casing through a discharge port.

Images