JPH10225606A - Method of controlling rotary drum filter and controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a control method for improving operation efficiency of a rotary drum filter and relieving the raw water concentration in a raw water storing part. SOLUTION: In a control method for a rotary drum filter constituted so that a rotary drum 9 on whose outer peripheral surface a filter cloth 8 is spread is freely rotatably installed in a tank filter 1, that raw water is introduced to inside the rotary drum 9, and that filtration is performed while the rotary drum 9 is rotated, a filter cloth 8 is washed for prescribed time after raw water supply is stopped. And when the level in a raw water storing part 3 for storing raw water attains the prescribed one, the raw water in the raw water storing part 3 is drained by prescribed quantity.

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 such as pools and industrial water using a rotary drum having a filter cloth stretched on an outer peripheral surface.

[0002]

2. Description of the Related Art In general, as a device for filtering water such as pools and industrial water, a rotating drum having a filter cloth stretched on an outer peripheral surface is used. Raw water is introduced into the rotating drum, and the rotating drum is rotated. Various rotary drum type filtration devices for filtering raw water by passing the same through a filter cloth have been proposed.

Conventionally, this kind of operation control method of a rotary drum type filtration device has been proposed by a feed pump provided in a raw water supply line for supplying raw water from a raw water supply unit such as a pool or industrial water to the rotary drum type filtration device. At the same time as stopping
The operation of the rotary drum type filtration device is also controlled to stop. However, if the operation of the rotary drum type filtration device is stopped at the same time as the supply of the raw water is stopped, the suspended matter mixed in the raw water remaining in the rotary drum adheres to the filter cloth and remains without being washed. Therefore, when the raw water is filtered at the next operation, the filter cloth becomes clogged, which is a problem. That is, the suspension adhered to the filter cloth adheres to the filter cloth by the next cleaning and becomes clogged with the filter cloth, so that extra filter cloth cleaning time is required at the next cleaning.

[0004] When the rotary drum type filtration device is operated for a long time, suspended solids may precipitate at the bottom of the raw water storage portion of the filtration tank, and the raw water may be gradually concentrated to reduce the flow rate.
Therefore, there is a problem that the amount of the treated water filtered becomes smaller than the supply amount of the raw water, and the water level in the raw water storage section rises.

[0005]

SUMMARY OF THE INVENTION In view of the above problems, the present invention provides a control method for improving the operation efficiency of a rotary drum type filtration device and reducing the concentration of raw water in a raw water storage section. It is an object to provide a control device.

[0006]

Means for Solving the Problems The present invention has been made to solve the above problems, and the invention according to the first aspect is directed to a method in which a rotary drum having a filter cloth stretched on an outer peripheral surface is provided with a filter tank. Is installed in a rotatable manner, the raw water is introduced into the inside of the rotary drum, a control method in a rotary drum type filtration device configured to perform filtration while rotating the rotary drum, after stopping supply of the raw water The filter cloth is washed for a predetermined time, and the invention according to claim 2 is characterized in that a rotary drum having a filter cloth stretched on an outer peripheral surface is rotatably installed in a filtration tank, The method for controlling a rotary drum type filtration device configured to perform filtration while rotating the rotary drum by introducing raw water into the inside of the raw water, when a water level of a raw water storage unit that stores the raw water reaches a predetermined water level , The raw water storage unit The invention is characterized in that a predetermined amount of raw water is drained, and the invention according to claim 3 further comprises a rotatable drum having a filter cloth stretched on an outer peripheral surface, rotatably installed in a filter tank, and the inside of the rotatable drum. A control device in a rotary drum type filtration device configured to perform filtration while introducing raw water and rotating the rotary drum, wherein a raw water storage unit that stores the raw water is provided with a water level control device, and the raw water storage unit is provided. A drain line having a motorized valve is connected to a lower part of the motor, and the water level control device and the motorized valve are connected via a signal line.

[0007]

Next, an embodiment of the present invention will be described. The present invention is realized as being applied to an operation control method of a rotary drum type filtration device. First, in the control method according to claim 1 of the present invention,
Even after the supply of the raw water to the rotary drum type filtration device is stopped, control is performed so that the filter cloth of the rotary drum is washed for a predetermined time. That is, the washing device provided in the rotary drum type filter device is driven to wash the filter cloth, and the washing water is discharged out of the system, so that the filter cloth is not clogged. Therefore, at the next filtration, raw water can be filtered smoothly and efficiently.

In the control method according to the present invention, when the water level of the raw water storage section for storing raw water reaches a predetermined water level, control is performed such that a predetermined amount of raw water in the raw water storage section is drained. . That is, a predetermined amount of the raw water concentrated by the suspended matter precipitated in the raw water storage unit is discharged. Therefore, the concentration of the raw water in the raw water storage section is reduced, and the raw water can smoothly flow through the rotating drum.

According to a third aspect of the present invention, there is provided a control apparatus for detecting a water level in a raw water storage section for storing raw water, and a motor-operated valve provided at a lower portion of the raw water storage section. A line is connected, and the water level control device and the motor-operated valve are connected via a signal line.
According to the control device having the above configuration, when the water level in the raw water storage section reaches a preset water level, the water level control device detects the water level and notifies the motorized valve of this detection signal. Upon receiving the notification, the motor-operated valve opens for a preset time, closes after discharging a predetermined amount of raw water in the raw water storage unit from a discharge line.

As described above, according to the present invention, the efficiency of the next filtration operation of raw water can be improved by the cleaning operation of the filter cloth after the supply of raw water supplied to the rotary drum type filtration device is stopped. In addition, the decrease in the flow rate due to the increase in the suspended solids in the raw water in the raw water storage unit is caused by detecting the water level in the raw water storage unit and discharging a predetermined amount of concentrated raw water when the water level reaches the predetermined water level. The efficiency of water flow in the drum can be improved.

[0011]

Embodiments of the present invention will be described below 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 of the present invention has a basic configuration and is realized as a rotary drum 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.

Now, on the outside of the rotating drum 9, FIG.
As shown in FIG.
Back washing means 12 for washing the outside from the outside is arranged. The backwashing means 12 is for supplying the washing water downwardly to the outer surface of the filter cloth 8 as a jet stream directed toward the downstream side in the rotation direction of the rotary drum 9. Is increased so as to increase the permeability of the filter cloth 8. And this backwashing means 12
Is specifically constituted by a washing water supply pipe 14 in which a large number of outflow holes 13, 13,. The washing water flows down from each outflow hole 13 to the outer surface of the filter cloth 8 as a jet stream without flowing as in spraying. The washing water supply pipe 14 is installed so as to extend over substantially the entire length of the rotary drum 9 in the axial direction. Further, the washing water supply pipe 14 is configured to supply 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 15. ing. The cleaning water supply pipe 15 is provided with a pump 16 for supplying treated water as cleaning water to the cleaning water supply pipe 14. Therefore, by operating this pump 16, the treated water in the filtration section 4 is supplied to the washing water supply pipe 14, and its operation is turned on and off by the controller 17 (see FIG. 2). Controlled.

Inside the rotary drum 9, a recovery hopper 19 for recovering the washing wastewater from the backwashing means 12 at an upper position thereof and discharging the same to the outside of the filtration tank 1 through a drainage pipe 18. Is arranged. Like the washing water supply pipe 14, the collecting hopper 19 is installed so as to extend over substantially the entire length of the rotary drum 9 in the axial direction. Further, inside the rotary drum 9, solid substances such as leaves of relatively large trees mixed in the raw water and sludge-like substances such as mud separated from the inside of the filter cloth 8 are stored in the recovery hopper 19. Basket 20
And a brush 21 are provided.

Here, the overall filtration processing in the above configuration will be briefly described. First, raw water from a raw water supply source such as a pool is supplied to the raw water storage section 3 of the filtration tank 1 through a raw water supply pipe 22. You. The raw water supplied to the raw water storage unit 3 is introduced into the inside of the rotary drum 9 through the communication hole 5 of the raw water storage unit 3 and 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. The treated water flowing into the filtration unit 4 overflows the weir plate 7 provided in the filtration unit 4, flows into the buffer tank unit 6, and is supplied to the pool and the like via the treated water supply pipe 23. Is done. On the other hand, the washing wastewater washed by the washing water flowing down as a jet stream from the washing water supply pipe 14 as the backwash means 12 is collected by the collection hopper 1 installed in the rotating drum 9.
9, and is discharged out of the filtration tank 1 through a drain pipe 18. The cleaning of the filter cloth 8 by the backwashing means 12 is performed by the controller 17 at a predetermined interval set in advance.
This is performed by the N and OFF signals.

Next, a control device according to the present invention will be described. The control device includes a water level control device 24 in the raw water storage unit 3, a drain line 25 connected to a lower portion of the raw water storage unit 3, an electric valve 26 provided in the drain line 25, and an electric valve 26. And the water level control device 2
4 is connected via a signal line 27. The water level control device 24 includes an electrode rod 28 for detecting an upper limit water level and an electrode rod 29 for detecting a lower limit water level.

Next, a control method according to the present invention will be described. This control method is performed in order to improve the operation efficiency of the rotary drum type filtration device having the above-described configuration, and the first control method is that supply of raw water from a raw water supply source such as a pool is stopped. Control method when the
Even after the supply pump (not shown) provided in the raw water supply pipe 22 shown in FIG. 1 is stopped, the rotary drive of the rotary drum 9 is continuously performed for a predetermined time (for example, 2 to 5 minutes), and the cleaning is performed. The pump 16 provided in the water supply pipe 15 is driven to wash the wash water, and
To wash the filter cloth 8 and the washing wastewater is collected in the collection hopper 1
The water is discharged from the drainage pipe 18 to the outside of the system via the pipe 9. By the washing for the predetermined time, the suspended matter adhering to the filter cloth 8 is washed away, and the suspended matter remains without adhering. Therefore, at the next filtration, the raw water can be filtered smoothly and efficiently without clogging of the filter cloth 8.

The second control method is a control method when the rotary drum type filtration device is operated for a long time. Precipitates and the raw water is gradually concentrated, so that the flow rate of the filter cloth 8 is reduced, the water level of the raw water storage unit 3 is increased, and the raw water is prevented from flowing out of the filtration tank 1 to the outside. The amount of water passing through the filter cloth 8 is returned to normal. That is, when the electrode rod 28 for detecting the upper limit water level of the water level control device 24 provided in the raw water storage unit 3 detects the water level, the detection signal is transmitted to the motor-operated valve 26 provided in the drain line 25 via the signal line 27. I do. The motor-operated valve 26 that received the notification opens and closes when the water level cuts off the lower end of the lower-limit water level detection electrode rod 29. Therefore, the suspended matter settled at the bottom of the raw water storage unit 3 is discharged, so that the concentration of the suspended matter in the raw water decreases, and the flow rate of the filter cloth 8 returns to normal.

Next, another embodiment of the control device will be described. The water level control device 24 is provided with, for example, an electrode rod 28 for detecting an upper limit water level and a timer (not shown). According to this configuration, when the upper-limit water level detection electrode rod 28 detects a water level, the detection signal is reported to the motor-operated valve 26 and the motor-operated valve 26 is opened. At the same time, the timer starts. Then, after a lapse of a predetermined time,
The electric valve 26 is closed by a return signal of the timer.

[0021]

As described above, according to the control method of the present invention, the filter cloth is controlled to be washed for a predetermined time after the supply of raw water to the rotary drum type filtration device is stopped. There is no clogging of the filter cloth, and the rotary drum type filter can be operated efficiently. Further, when the raw water storage section reaches a predetermined water level, a predetermined amount of the raw water in the raw water storage section is discharged, so that the raw water is prevented from flowing out of the raw water storage section and the raw water concentration And the water flow through the filter cloth can be made normal.

[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 8 Filter cloth 9 Rotary drum 24 Water level control device 25 Drain line 26 Motorized valve 27 Signal line

Claims (3)

[Claims] 1. A rotary drum 9 having a filter cloth 8 stretched around its outer peripheral surface.
A rotatable drum filter device that is rotatably installed in the filtration tank 1, introduces raw water inside the rotary drum 9, and performs filtration while rotating the rotary drum 9, A method for controlling a rotary drum type filtration device, wherein the filter cloth 8 is washed for a predetermined time after the supply of the raw water is stopped. 2. A rotary drum 9 having a filter cloth 8 stretched around its outer peripheral surface.
A rotatable drum filter device that is rotatably installed in the filtration tank 1, introduces raw water inside the rotary drum 9, and performs filtration while rotating the rotary drum 9, A method of controlling a rotary drum type filtration device, comprising: discharging a predetermined amount of raw water in the raw water storage unit 3 when the raw water storage unit 3 that stores the raw water reaches a predetermined water level. 3. A rotating drum 9 having a filter cloth 8 stretched around its outer peripheral surface.
A rotating drum type filtration device configured to rotatably install in the filtration tank 1, introduce raw water into the inside of the rotating drum 9, and perform filtration while rotating the rotating drum 9, A water level control device 24 is provided in the raw water storage unit 3 for storing the raw water, and a drainage line 25 having an electric valve 26 is connected to a lower portion of the raw water storage unit 3 to connect the water level control device 24 and the electric valve 26 with each other. Is connected via a signal line 27 to the control device of the rotary drum type filtration device.