JP3104605B2 - Cleaning control method and cleaning control device for rotary drum type filtration device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary drum type filtration device for filtering water in pools, ponds, swamps, etc. using a rotary drum having a filter cloth stretched on an outer peripheral surface thereof. The present invention relates to a method and an apparatus for controlling the cleaning of a filter cloth stretched on the outer peripheral surface of a rotary drum.

[0002]

2. Description of the Related Art Conventionally, as a rotary drum type filtration device,
Japanese Patent Publication No. Hei 4-9081, Japanese Patent Publication No. Hei 6-96081, Japanese Examined Patent Publication No. 4-8077, and Japanese Patent Publication No. Hei 7-17366 are known. In general, in a rotary drum type filtration device as in the conventional example, the filtration accuracy of the filter cloth stretched on the outer peripheral surface of the rotary drum is good when the particle size of inclusions in water is about 10 μm or more. However, there is a problem that the trapping rate is poor for a particle size smaller than that, and development of a filter cloth with high filtration accuracy has been awaited.

[0003]

SUMMARY OF THE INVENTION In view of the above-mentioned problems, the present invention provides a high-precision filter that can reliably capture even inclusions in water having a particle size of about 10 .mu. It is intended to realize filtration.

[0004]

Means for Solving the Problems The present invention has been made to solve the above-mentioned problems, and the invention according to claim 1 is to dispose a rotary drum having a filter cloth stretched on an outer peripheral surface in a filtration tank. A washing means for rotatably installed, introducing raw water into the inside of the rotating drum, filtering while rotating the rotating drum, and further washing a surface of the filter cloth from inside the rotating drum; A rotary drum type filtration device provided with a backwash means for washing the back surface of the filter cloth from the outside of the drum, usually intermittently the filter cloth is provided by one or both of the front washing means and the backwash means. When the water level in the rotating drum reaches the set water level,
The filter cloth is continuously washed by the two washing means for a predetermined time, and the invention according to claim 2 is characterized in that:
A rotating drum having a filter cloth stretched on the outer peripheral surface is rotatably installed in a filtration tank, raw water is introduced into the inside of the rotating drum, filtration is performed while rotating the rotating drum, and further, inside of the rotating drum. A washing device for washing the front surface of the filter cloth, and a back drum washing device for washing the back surface of the filter cloth from the outside of the rotating drum;
A water level detecting means for detecting a water level in the rotary drum, wherein the front washing means and the back washing means perform a cleaning operation continuously for a predetermined time based on a detection value of the water level detecting means;
Is provided with a control device for performing such control .

[0005]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of the present invention will be described. The present invention is realized as being applied to washing of filter cloth of a rotary drum type filter device.
Generally, in this type of filtration device, the surface washing means and the backwashing means on both the inner and outer sides of the rotary drum are simultaneously operated to continuously and continuously wash the filter cloth stretched on the outer peripheral surface of the rotary drum. The method has been adopted. However, according to this method, if the particle size of the contaminants in the raw water is about 10 μm or less, the trapping rate is poor and the filtration accuracy is low. Therefore, in the present invention, when the filter cloth is in a clogged state, the filtering accuracy is improved, the filtration efficiency is reduced, and attention is paid to the point that the water level in the rotating drum rises,
The two cleaning means are intermittently operated for cleaning. That is, the filtering accuracy is improved by giving a certain clogged state to the surface of the filter cloth (the filter cloth surface located inside the rotary drum).

That is, according to the present invention, the filter cloth is intermittently washed by one or both of washing from inside of the rotating drum by means of surface washing and washing from outside by means of backwashing means. Then, with the intermittent washing, the clogging state gradually progresses on the surface of the filter cloth, and with this progress, the filtration efficiency decreases, and as a result, the water level in the rotating drum rises. When the rising water level reaches a certain set water level, the two cleaning means are simultaneously operated for cleaning, and are continuously cleaned for a predetermined time. By the continuous washing by the two washing means over a predetermined period of time, the clogged state of the filter cloth is released, the filtration efficiency returns to the original, and the water level in the rotating drum falls. Thereafter, the process returns to the usual intermittent cleaning as described above, and the same cleaning is repeated thereafter. Thus, by such a control method, high-accuracy filtration is realized while maintaining a predetermined filtration accuracy without lowering the capture rate even with existing filter cloths.

The control device according to the present invention further comprises a water level detecting means for detecting a water level in the rotating drum, and a control apparatus for controlling the cleaning operation of the two cleaning means based on the detected value of the water level by the water level detecting means. , High-accuracy filtration is realized.

Hereinafter, specific embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is an explanatory view schematically showing the entire rotary drum type filtration device according to the present invention.

In FIG. 1, the rotary drum type filtration device according to the present invention has a basic configuration in which a rotary drum is installed in a filtration tank 1. The filtration tank 1 is composed of a raw water storage section 3 and a filtration processing section 4 partitioned by a partition 2, and the raw water storage section 3 and the filtration processing section 4 are formed by circular communication holes 5 formed in the partition 2. Is communicated with. Further, a dam plate 7 that defines a buffer tank unit 6 for temporarily storing the filtered treated water is provided in the filtration unit 4.

In the filtering section 4, a filter cloth 8 is provided on the outer peripheral surface.
Is rotatably accommodated and installed. The filter cloth 8 is stretched so that its filtration surface is inside the rotating drum 9 and its back surface is outside the rotating drum 9. The rotary drum 9 is configured such that one end side in the axial direction, that is, the partition 2 side is open, and the other end side, that is, the weir plate 7 side is closed. The opening at one end corresponds to the communication hole 5 formed in the partition wall 2 with substantially the same diameter. Therefore, the raw water in the raw water storage section 3 passes through the communication hole 5 and the opening. The raw water is continuously filtered through the filter cloth 8 by the rotation of the rotating drum 9 as described later. Here, the communication hole 5 and the opening of the rotary drum 9 are not described in detail in order to prevent the raw water from leaking from the opening and flowing directly into the filtration unit 4. It is sealed by an appropriate sealing structure using 10 or the like. A bearing 11 is provided on the closed side of the other end of the rotating drum 9 to restrict the axial movement of the rotating drum 9 due to a thrust load.

Here, the rotation mechanism of the rotary drum 9 will be described. The rotary drum 9 is composed of four rotatable support rollers 1 installed at the bottom in the filtering section 4.
Are placed on 2, 12,.... A suitable chain (not shown) is wound around the outer peripheral surface of the end on the closed side of the rotary drum 9, and the sprocket 14 of the motor 13 meshes with this chain. Therefore, the rotating drum 9 is rotated on each support roller 12 by the motor 13 via the sprocket 14 and the chain.

The inside of the rotary drum 9 is shown in FIG.
As schematically shown in FIG. 1, a surface washing means 15 provided with a number of nozzles (symbols omitted) for washing the filter cloth 8 from the inside is disposed at the upper position. This surface washing means 15
Is installed so as to extend over substantially the entire length of the rotary drum 9 in the axial direction. And this surface washing means 15
Is configured to use the treated water after filtration in the filtration unit 4 as washing water, and is connected to the filtration unit 4 via a washing water supply pipe 16. The cleaning water supply pipe 16 is supplied with treated water as cleaning water by the surface cleaning means 1.
A pump 17 is provided for supply to the pump 5. ON / OFF of the pump 17 is controlled by a control device described later. Further, inside the rotary drum 9, washing drainage by the surface washing means 15 is collected, and this is drained into the drainage pipe 1.
Recovery hopper 19 which is discharged out of the filtration tank 1 through
Are arranged. This collection hopper 19 is also installed in a state of extending over substantially the entire length of the rotary drum 9 in the axial direction, similarly to the surface washing means 15.

Inside the rotary drum 9, solid matters such as relatively large leaves mixed with raw water and sludge such as mud separated from the inside of the filter cloth 8 are stored in the collection hopper 19. Bucket 20 and brush 21 for cleaning
Is provided.

On the outside of the rotary drum 9, a backwash having a number of nozzles (symbols omitted) for washing the filter cloth 8 from outside at a position corresponding to the collection hopper 19 above the outside. Means 22 are arranged.
The backwashing means 22 is also provided so as to extend over substantially the entire length of the rotary drum 9 in the axial direction. And
The backwashing unit 22 is configured to use the treated water after filtration in the filtration unit 4 as washing water. The backwashing unit 22 is connected to the backwashing water supply branch 16 from the washing water supply pipe 16. It is connected via a pipe 23.

By the way, according to the present invention, the cleaning means 15 and 22 are controlled as follows. First, the filter cloth 8 is usually washed from the inside of the rotating drum 9 (that is, washed by the washing means 15) or backwashed from the outside of the rotating drum 9 (that is, the backwash). Intermittent cleaning is performed by one or both of the means 22). Then, with the intermittent washing, the clogging state on the surface of the filter cloth 8 gradually progresses inside the rotary drum 9, and the filtration efficiency decreases with the progress, and as a result, the rotation The water level in the drum 9 rises. When the water level rise reaches a certain set water level, the cleaning means 15 and 22 are simultaneously operated for cleaning, and are continuously cleaned for a predetermined time. The continuous washing by the two washing means 15 and 22 for a predetermined period of time releases the clogged state of the filter cloth 8, the filtration efficiency returns to the original level, and the water level in the rotary drum 9 drops. Thereafter, the process returns to the usual intermittent cleaning as described above, and the same cleaning is repeated thereafter.

Here, a configuration for detecting the water level in the rotary drum 9 will be described. The rotary drum 9 is provided with a water level detecting means 24 such as a sensor for detecting the water level inside the rotary drum 9. The water level detecting means 24 detects that the water level in the rotary drum 9 has reached the upper limit water level, that is, the water level at which the water level becomes higher than the upper limit, and the filtering function cannot be performed. Based on the filtration conditions such as the pollutant concentration of the
Furthermore, it is set in advance based on the processing capacity of the filtration device itself. The water level detection means 24 is connected to a control device 26 via a signal line 25, detects that the water level in the rotary drum 9 has reached a set water level, and sends the detection signal to the control device 26. Output. This control device 2
6 is based on the detection value from the water level detection means 24,
The washing operation of the two washing means 15 and 22 is controlled by a front washing electromagnetic valve 27 provided in the washing water supply pipe 16 and a back washing electromagnetic valve 28 provided in the back washing water supply pipe 23. And signal lines 29 and 30 respectively, and further connected to the pump 17 via a signal line 31. Thus, the control device 26 is also configured to control the intermittent cleaning operation of the two cleaning means 15 and 22 in the normal state. That is, the control device 26
Is the ON / OFF of the pump 17 and the two solenoid valves 2
By controlling the opening and closing of the cleaning means 7 and 28, the cleaning operation of the cleaning means 15 and 22 is controlled.

Here, the two cleaning means 15, 22 are used.
The intermittent washing operation in the normal state will be described. This washing operation is basically to keep the filter cloth 8 in a constant clogged state.
6, one of the two cleaning means 15, 22 is intermittently cleaned for a predetermined time. That is, cleaning is performed only by the surface cleaning means 15 for one minute,
Repeat the control to stop washing for a minute. Conversely, control by only the backwashing means 22 is suitable depending on the implementation. Further, a control for simultaneously performing the cleaning operation for both the cleaning means 15 and 22 for 30 seconds and stopping the cleaning for 3 minutes is also suitable for the implementation.

Further, the overall filtration process in the above configuration will be briefly described. First, raw water from a raw water supply source such as a pool or a pond is supplied to a filtration tank 1 through a raw water supply pipe 32.
Is supplied to the raw water storage unit 3. The raw water supplied to the raw water storage unit 3 is supplied to the communication hole 5 and the rotating drum 9 of the raw water storage unit 3.
Through the opening of the rotary drum 9. The raw water introduced into the rotating drum 9 is continuously filtered through the filter cloth 8 as the rotating drum 9 rotates, and flows into the filtration processing unit 4 as treated water. Pool filtration treatment section treatment water which has flowed into the 4 overflows the weir plate 7 provided in the filtration unit 4 flows into the buffer tank 6, via the treated water supply pipe 33 from here, IkeHitoshi Supplied to On the other hand, the washing wastewater washed by the front washing means 15 and the backwashing means 22 is collected by a collecting hopper 19 installed in the rotating drum 9 and discharged to the outside of the filtration tank 1 through a drainage pipe 18.

Next, based on the present invention, a specific experimental example of cleaning the filter cloth 8 will be described. First, a description will be given of the filtration of the pool having a relatively low pollutant concentration. As an intermittent cleaning by only the surface washing means 15, the washing is performed for 1 minute and the washing is stopped for 3 minutes. Clogging gradually appears on the rotating drum 9
The water level inside has risen. Here, a rapid clogging state did not occur, that is, a rapid rise in the water level was not observed, and it was confirmed that this intermittent cleaning control was sufficient. Then, when the water level detecting means 24 detects that the water level in the rotary drum 9 has reached a preset water level, control is performed to perform simultaneous cleaning by the front washing means 15 and the backwash means 22 for one minute. Then, the clogged state of the filter cloth 8 is released, and the water level in the rotary drum 9 is set to a normal water level (generally, the height is substantially the same as the height of the rotation axis of the rotary drum 9,
The raw water supply amount from the raw water supply pipe 31 is adjusted. )
Returned to. By repeating this washing operation, the predetermined filtration accuracy was maintained without lowering the capture rate of the contaminants in the raw water.

As a second experimental example, filtration of a pond having a relatively high SS quality will be described.
As an intermittent washing with only the
The control for stopping the washing for one minute and the simultaneous washing for both washing means 15 and 22 for one minute when the water level detecting means 24 detects the set water level were performed. Capture rate of contaminants contained in
% To 60%.

[0021]

As described above, according to the present invention, the intermittent washing by the two washing means and the simultaneous washing are controlled, so that the trapping rate is not reduced even with the existing filter cloth.
Predetermined filtration accuracy can be maintained, and high-precision filtration can be realized. Further, according to the present invention, an efficient filtering operation can be performed with a simple control and a simple configuration, and therefore, this type of cleaning is very effective as a cleaning in a rotary drum type filtering device.

[Brief description of the drawings]

FIG. 1 is an explanatory view schematically showing the entire rotary drum type filtration device according to the present invention, which is partially shown in section.

FIG. 2 is an explanatory diagram schematically showing a cross section of a central portion in the left-right direction of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Filtration tank 3 ... Raw water storage part 4 ... Filtration processing part 6 ... Buffer tank part 8 ... Filter cloth 9 ... Rotary drum 15 ... Surface washing means 16 ... Wash water supply pipe 17 ... Pump 19 ... Recovery hopper 22 ... Back washing means 23 ... Backwash water supply pipe 24 ... Water level detecting means 26 ... Control device 27 ... Surface wash solenoid valve 28 ... Backwash solenoid valve

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Toshio Higaki 7th Horie-cho, Matsuyama-shi, Ehime Miura Industrial Co., Ltd. (72) Inventor Yoshiyuki Fukuoka 7th Horie-cho, Matsuyama-shi, Ehime Miura Industrial Co., Ltd. Examiner Kenichi Mori (58) Field surveyed (Int. Cl. ⁷ , DB name) B01D 33/44

Claims (2)

(57) [Claims] 1. A rotary drum 9 having a filter cloth 8 stretched around its outer peripheral surface.
Is rotatably installed in the filtration tank 1, raw water is introduced into the inside of the rotating drum 9, filtration is performed while rotating the rotating drum 9, and the surface of the filter cloth 8 is further rotated from the inside of the rotating drum 9. Washing means 15 for washing the back surface of the filter cloth 8 from outside of the rotary drum 9;
In the rotary drum type filtration device provided with, the intermittent cleaning of the filter cloth 8 is usually performed by one or both of the front washing means 15 and the backwashing means 22, and the water level in the rotary drum 9. Washing the filter cloth 8 continuously for a predetermined time by the two washing means 15 and 22 when the water reaches a set water level. 2. A rotary drum 9 having a filter cloth 8 stretched around its outer peripheral surface.
Is rotatably installed in the filtration tank 1, raw water is introduced into the inside of the rotating drum 9, filtration is performed while rotating the rotating drum 9, and the surface of the filter cloth 8 is further rotated from the inside of the rotating drum 9. Washing means 15 for washing the back surface of the filter cloth 8 from outside of the rotary drum 9;
And a water level detecting means 24 for detecting the water level in the rotary drum 9, and based on the detection value of the water level detecting means 24,
5 and the backwashing means 22 performs the cleaning operation continuously for a predetermined time.
A cleaning control device for a rotary drum type filtration device, comprising a control device 26 for performing control to perform the cleaning.