JP6795202B2 - How to operate the disc screen device - Google Patents

Description

The present invention relates to an operating method of a disc screen device for removing impurities and the like in wastewater.

A disc screen device is a dust removing device that removes impurities in drainage. A typical disc screen device includes a rotary disc screen formed by arranging a plurality of rings in parallel, thereby capturing impurities in the wastewater. The disc screen device is provided with a cleaning device for removing impurities adhering to the disc screen, which enables continuous operation. The disc screen is also called a drum screen or a rotating screen, and the disc screen device is also called a drum screen device.

In the disc screen device, there is a cleaning device using a rotary scraper as well as a fixed scraper as a cleaning device (see, for example, Patent Documents 1 and 2). The disc screen device described in Patent Document 1 has one rotary scraper, but the disc screen device described in Patent Document 2 comprises two or more rotary scrapers to form a cleaning device.

Japanese Unexamined Patent Publication No. 8-199538 Japanese Unexamined Patent Publication No. 2017-35683

In the cleaning device described in Patent Document 2, the cleaning device is composed of a plurality of rotary scrapers, and the arrangement thereof is devised, so that it is difficult for contaminants to accumulate on the rotary scrapers, but the contaminants for a long time. If the removal operation is performed, it is inevitable that contaminants will accumulate on the rotating scraper.

Patent Document 1 and Patent Document 2 describe that the cleaning device should be cleaned regularly, and the cleaning procedure thereof. The cleaning device described in Patent Document 1 and the cleaning device described in Patent Document 2 differ in the cleaning procedure of the cleaning device in detail because the number of rotating scrapers to be configured is different. However, when cleaning the cleaning device, the device is used. It is described that the water supply and the rotation of the disc screen are stopped, and the rotary scraper is rotated in the reverse direction for cleaning.

In the disc screen device provided with the cleaning device using the rotary scraper as described above, it is necessary to stop the water supply to the device during the cleaning operation of the cleaning device. Therefore, when the load on the entire facility of the processing facility where the disc screen device is installed is high, there is a problem that the water supply to the disc screen device cannot be stopped and the cleaning device cannot be cleaned.

An object of the present invention is to provide a method of operating a disc screen device capable of cleaning the cleaning device without stopping water supply to the disc screen device.

The present invention is a method of operating a disk screen device including an inflow tank for receiving a processing liquid, a disk screen for removing impurities in the processing liquid, and a cleaning device for removing impurities adhering to the disk screen. The cleaning device is provided with n or more rotary scrapers (n is an integer of 2 or more) that sequentially mesh with each other to transfer and remove the contaminants, and during the contaminant removal operation for continuously removing the contaminants. , A method of operating a disc screen device, which comprises performing a rewinding operation of an end rotating scraper composed of the following first to third steps without stopping acceptance of a processing liquid.
First step: The rotation speed of the disc screen is increased, and the water level of the inflow tank is forcibly lowered.
Second step: After the first step, the disc screen and all rotating scrapers are stopped.
Third step: After the second step, only the terminal rotating scraper is rotated to provide a new scraped surface.

In the method of operating the disc screen device of the present invention, the rotary scraper is a first rotary scraper that meshes with the disc screen, a second rotary scraper that meshes with the first rotary scraper, and a third rotary scraper that meshes with the second rotary scraper. The terminal rotation scraper is configured, and the rotation operation of the third step is characterized in that only the third rotation scraper is rotated in the reverse direction, and then the third rotation scraper is rotated in the normal direction. And.

Further, the operation method of the disc screen device of the present invention is characterized in that, during the contaminant removal operation, the terminal rotating scraper rotates forward at predetermined intervals.

Further, in the operation method of the disk screen device of the present invention, the rewinding operation of the end rotating scraper is performed until the end rotating scraper makes one rotation during the contaminant removal operation.

According to the present invention, it is possible to provide a method of operating a disc screen device capable of cleaning the cleaning device without stopping water supply to the disc screen device.

It is a perspective view of the disk screen apparatus 1 which can carry out the operation method of the disk screen apparatus of this invention. It is a block diagram of the disk screen apparatus 1 which can carry out the operation method of the disk screen apparatus of this invention. It is a block diagram of the operation control device 61 of the disk screen device 1 of FIG. It is a block diagram of the cleaning device 31 of the disk screen device 1 of FIG. It is a figure which shows the meshing state of the disk screen 21 and the rotary scraper of the disk screen apparatus 1 of FIG. It is a layout drawing of the rotary scraper which constitutes the cleaning device 31 of the disk screen device 1 of FIG. It is a flowchart which shows the procedure of the 1st operation method of the disk screen apparatus 1 of FIG. It is a flowchart which shows the procedure of the operation method of the disk screen apparatus of this invention.

The present invention relates to a method of operating a disc screen device including a cleaning device using a rotary scraper. However, prior to the description of the present invention, the disc screen device 1 capable of preferably using the method of operating the disc screen device according to the present invention. The configuration will be described. The present invention is not limited to the disc screen device 1 shown in FIGS. 1 to 6, and can be widely used in a disc screen device including a cleaning device using a rotary scraper.

FIG. 1 is a perspective view of a disc screen device 1 capable of carrying out the operation method of the disc screen device of the present invention. FIG. 2 is a configuration diagram of the disc screen device 1, FIG. 3 is a configuration diagram of the operation control device 61 of the disc screen device 1, and FIG. 4 is a configuration diagram of the cleaning device 31 of the disc screen device 1. FIG. 5 is a diagram showing the meshing state of the disc screen 21 of the disc screen device 1 and the rotary scraper, and FIG. 6 is a layout diagram of the rotary scrapers constituting the cleaning device 31 of the disc screen device 1.

The disc screen device 1 is a device that continuously receives sewage, drainage, waste liquid, etc., removes contaminants (residues) such as flocs and scums contained therein, and discharges the sewage or the like from which the impurities have been removed. It includes a disc screen 21 for removing impurities, a casing 11 for supporting the disc screen 21, a cleaning device 31 for cleaning the disc screen 21, a disc screen 21, a drive device 51 for driving the cleaning device 31, and an operation control device 61. Hereinafter, each configuration will be described in detail with the treated liquid as wastewater.

The casing 11 has a rectangular parallelepiped shape capable of accommodating the disc screen 21. A drainage inlet 13 for receiving drainage and a filtrate outlet 14 for discharging the filtrate from which impurities have been removed are provided on one side surface of the casing 11. Inside the casing 11, an inflow tank 15 for guiding the drainage flowing in from the drainage inflow port 13 to the disk screen 21 and an outflow tank 16 for guiding the filtrate from which impurities have been removed by the disk screen 21 to the filtrate outflow port 14 are provided. ing.

The inflow tank 15 is provided with a water level control tank (not shown) that communicates with the inflow tank 15, and the water level control tank is provided with a level meter 17 that detects the water level. The water level of the inflow tank 15 can be detected via the level meter 17, and the level meter 17 is connected to the operation control device 61 and transmits a signal to the operation control device 61.

The disc screen 21 is a cylindrical rotating screen that captures and removes contaminants in the wastewater sent from the inflow tank 15. In the disc screen 21, a plurality of ring-shaped discs 22 are arranged at predetermined intervals and fixed to a support 24 provided at the tip of the arm 23 to form a screen. A boss 25 through which the rotating shaft 26 is inserted is provided at the base end portion of the arm 23, and the boss 25 is fixed to the rotating shaft 26. Both ends of the rotating shaft 26 are supported by bearings 27, and the disc screen 21 is attached to the casing 11 so as to be rotatable and to face the end of the inflow tank 15.

The cleaning device 31 is a device that removes impurities adhering to the disc screen 21, and is composed of a plurality of rotary scrapers. These are provided on the downstream side of the disc screen 21. The downstream side of the disc screen 21 is opposite to the inflow tank 15. Details of the structure of the cleaning device 31 and the like will be described later.

The drive device 51 is a device that rotates the disc screen 21, and includes a drive motor 52 with a transmission and a power transmission mechanism 53 including gears, chains, and the like that transmit the rotation of the drive motor 52 to the disc screen 21. Consists of. The drive motor 52 is attached to the upper part of the casing 11 and is connected to the disc screen 21 via the power transmission mechanism 53.

The drive device 51 further includes a first rotary scraper 33, a power transmission mechanism 54 that connects the second rotary scraper 41 and the drive motor 52, and a safety device 56 that prevents the drive motor 52 from being overloaded.

The safety device 56 includes a torque detection mechanism 57 that detects the torque of the rotating shaft of the transmission connected to the drive motor 52, and a timer 58. The torque detection mechanism 57 includes a limit switch (not shown) that turns on when the torque exceeds a set value and outputs a signal for stopping the drive motor 52.

The timer 58 is connected to the drive motor 52, the limit switch, and the operation control device 61, and receives a signal from the operation control device 61 to start the operation. The timer 58 stops outputting the signal from the limit switch to the drive motor 52 until the set time elapses when the operation is started. Therefore, the drive motor 52 does not stop even if the limit switch is turned on while the timer 58 is operating.

On the other hand, when the timer 58 is not operating, the signal from the limit switch is immediately output to the drive motor 52. Therefore, if the limit switch is turned on while the timer 58 is not operating, the drive motor 52 is immediately stopped. The usage of the safety device 56, including the timing of signal transmission from the operation control device 61 to the timer 58, the set time of the timer 58, and the like, will be described in the operation procedure of the disc screen device 1.

The operation control device 61 is a device that controls the operation of the disk screen device 1 according to a predetermined procedure, and is an input unit 65, an output unit 66, a storage unit 67, a calculation unit 68, a control unit 69, an input / output interface 70, and a timer. And the timing means 71 is provided.

A program and set values for controlling the operation of the disc screen device 1 are stored in the storage unit 67, and the operation control device 61 cooperates with the level meter 17 and follows a predetermined procedure according to the disc screen device 1. Control the operation of. Such an operation control device 61 can be realized by using a programmable controller and a computer.

Next, the cleaning device 31 for removing impurities adhering to the disc screen 21 will be described in detail. The cleaning device 31 is composed of three rotary scrapers from the first to the third, and removes and discharges impurities adhering to the disc screen 21.

In the cleaning device 31, the three rotary scrapers from the first to the third have the same shape and the same dimensions. The first rotary scraper 33, the second rotary scraper 41, and the third rotary scraper 42 are not limited to those having the same shape and the same size, but the same shape and the same size reduce the manufacturing cost. , Easy inventory management. Here, the same shape and the same dimensions include those having substantially the same shape and the same dimensions such that the number of disks constituting the rotary scraper is different by one or two. Hereinafter, the configuration and structure of the rotary scraper will be described using the first rotary scraper 33.

Roughly speaking, the first rotary scraper 33 has a shape in which comb teeth 35 are formed on the outer peripheral surface of a cylindrical member in which the rotary shaft 34 is arranged at the center. The comb teeth 35 are provided so as to mesh with all the screen eyes of the disc screen 21. Specifically, in the first rotating scraper 33, the disks 36 forming the teeth and the spacers 37 having a diameter smaller than the disk 36 are alternately arranged in the same number as the screen eyes of the disc screen 21, and the side plates 38 are further arranged on both sides. Are arranged, and these are fixed with tension bolts (not shown) to form comb teeth 35.

The diameter d _{1 of the} disk 36 is smaller than the diameter D of the disc screen 21, and the thickness t ₁ of _one disk 36 is set to be slightly smaller than the mesh width T of the screen of the disk screen 21. Further, the length L ₁ of the comb teeth 35 is set to be slightly longer than the width L of the disc 22 of the disc screen 21. The length L ₁ of the comb teeth 35 is 1/2 of the value obtained by subtracting the diameter d _{2 of the} spacer 37 from the diameter d _{1 of the} disk 36.

A through hole (not shown) is provided at the center of the disk 36, the spacer 37, and the side plate 38, and the rotating shaft 34 is inserted and fixed to the through hole. A rotation stopper is provided between the rotating shaft 34 and the disk 36 and the like, and the rotating shaft 34 and the disk 36 and the like rotate integrally.

As shown in FIG. 4 or 5, the first rotary scraper 33 including the above is rotatably fixed to the casing 11 via the bearing 39 so that the comb teeth 35 mesh with the screen of the disc screen 21. The engagement of the comb teeth 35 with the screen of the disc screen 21 means a state in which the comb teeth 35 are fitted with a slight gap with respect to the screen eyes.

The second rotation scraper 41 and the third rotation scraper 42 have the same structure as the first rotation scraper 33, and as shown in FIG. 4 or 5, the second rotation scraper 41 includes the first rotation scraper 33 and the third rotation scraper 33. The 42 is rotatably fixed to the casing 11 via the bearing 43 and the bearing 44, respectively, so as to mesh with the second rotary scraper 41.

The drive device of the first rotary scraper 33 and the second rotary scraper 41 includes a drive motor 52 and a power transmission mechanism 54 composed of gears, chains, and the like. That is, the first rotation scraper 33, the second rotation scraper 41, and the same drive motor 52 as the disk screen 21 are used as drive sources, and the first rotation scraper 33 and the second rotation scraper 41 move in conjunction with the disk screen 21.

The power transmission mechanism 54 that connects the first rotary scraper 33 and the second rotary scraper 41 with the drive motor 52 is configured as follows. Gears are attached to the rotating shafts 34 and 45 of the first rotating scraper 33 and the second rotating scraper 41, and are further connected to the drive motor 52 via a plurality of sprockets and a plurality of chains. By interposing a plurality of sprockets, the rotation speeds of the first rotation scraper 33 and the second rotation scraper 41 are amplified as compared with the rotation speeds of the disc screen 21.

On the other hand, the third rotation scraper 42 is configured to be capable of forward rotation, reverse rotation, and stop independently of the first rotation scraper 33 and the second rotation scraper 41 by using a dedicated drive device (not shown) directly connected to the motor. Has been done. Here, a drive motor with a brake is used in order to quickly switch the rotation of the third rotation scraper 42.

Next, the functions, roles, and arrangements of the first rotation scraper 33, the second rotation scraper 41, and the third rotation scraper 42 will be described. In FIG. 6, H is the horizontal height of the axis of the disc screen 21, and H _1, H ₂ , and H ₃ are the axes of the first rotation scraper 33, the second rotation scraper 41, and the third rotation scraper 42, respectively. The horizontal heights of the centers, V _1, V ₂ , and V ₃ , indicate the vertical directions of the axes of the first rotation scraper 33, the second rotation scraper 41, and the third rotation scraper 42, respectively.

In the cleaning device 31, the first rotary scraper 33 meshes with the disc screen 21, scrapes off the contaminants adhering to the disc screen 21, and the second rotary scraper 41 further transfers the contaminants to the second rotary scraper 41 and the third. Dirt is dropped and discharged from the meshing portion 48 with the rotating scraper 42.

In the cleaning device 31 that performs the above operation, the first rotating scraper 33 efficiently removes impurities from the disc screen 21, and the second rotating scraper 41 efficiently transfers impurities from the first rotating scraper 33. Further, in the second rotary scraper 41 and the third rotary scraper 42, it is desirable to arrange each rotary scraper so that impurities can be reliably dropped and discharged.

In order to efficiently remove impurities from the disc screen 21, the first rotary scraper 33 is preferably installed on the downstream side of the disc screen 21. Regarding the installation height of the first rotary scraper 33, the lower the position, the easier it is for the direction A (see FIG. 6) of the meshing portion 48 to face downward. On the other hand, if the first rotary scraper 33 is installed lower than the disc screen 21, the separated water easily overflows from the cleaning device 31. From these facts, it is preferable that the installation height of the first rotary scraper 33 is the same as or slightly lower than the installation height of the disc screen 21. Here, the installation height means the horizontal height of the axis of the rotation axis.

The second rotation scraper 41 and the third rotation scraper 42 are preferably arranged so that the orientation A of the meshing portion 48 is as directly below (vertically downward) as possible. If the meshing portion 48 is turned downward, impurities are likely to fall. The direction A of the meshing portion 48 refers to a direction in which the meshing portion 48 is divided into two, starting from the center of the meshing portion 48 (see FIG. 6). In order to direct the direction A of the meshing portion 48 directly downward, it is necessary to horizontally arrange the third rotation scraper 42 on the disc screen 21 side with respect to the second rotation scraper 41. Such an arrangement is such an arrangement of the third rotation scraper. This is not possible because 42 comes into contact with the disc screen 21 or the first rotating scraper 33.

From the above, the second rotation scraper 41 is located on the anti-disc screen 21 side with respect to the first rotation scraper 33 and is arranged diagonally downward by about 45 °, and the third rotation scraper 42 is attached to the second rotation scraper 41. On the other hand, it is preferably arranged on the disc screen 21 side at an angle of about 45 ° (see FIG. 6). The positional relationship, the third rotating scraper 42 is installed in comparison to a low position to a second rotating scraper 41, the vertical line V ₃ passing through the center point of the rotation axis 46 of the third rotating scraper 42 second rotating scraper 41 the disc screen 21 closer with respect to the vertical line V ₂ passing through the center point of the rotation axis 45 of the.

With such an arrangement, the third rotation scraper 42 is located substantially directly below the first rotation scraper 33, and the orientation A of the meshing portion 48 is approximately 45 ° diagonally. At this time, as shown in FIG. 6, in the third rotation scraper 42, since the lower part of the meshing portion 48 is substantially vertical, impurities are less likely to be caught by the third rotation scraper 42 and easily fall.

Next, the first operation method of the disc screen device 1 will be described. FIG. 7 is a flowchart showing the procedure of the first operation method of the disc screen device 1. The first operation method shown here is carried out when the load on the entire equipment of the processing facility where the disc screen device 1 is installed is not high and the water supply to the disc screen device 1 can be temporarily stopped. It is an operation method, and a cleaning operation can be performed after the contamination removal operation. In the following operations, the operation procedure is installed in the operation control device 61, and the operation control device 61 controls each operation to execute the operation. First, the operation pattern 1 will be described.

The operation control device 61 determines whether or not the inflow tank 15 is above a predetermined water level (step S1). The water level of the inflow tank 15 is determined based on a signal from a level meter 17 installed in the water level control tank that communicates with the inflow tank 15.

If a pump (not shown) that supplies drainage to the disc screen device 1 is activated and a predetermined flow rate of drainage is supplied to the disc screen device 1, the inflow tank 15 becomes a predetermined water level or higher. On the contrary, if the pump that supplies the drainage to the disc screen device 1 is stopped and the drainage is not supplied to the disc screen device 1, the inflow tank 15 is below the predetermined water level. When the inflow tank 15 is below a predetermined water level, the disc screen 21 and the cleaning device 31 are stopped and are in a standby state even if the main power of the disc screen device 1 is turned on.

When the operation control device 61 detects that the inflow tank 15 is above a predetermined water level in step S1, the disc screen 21 and the cleaning device 31 are operated to execute a contaminant removal operation for removing impurities in the drainage. (Step S2).

Specifically, the disc screen 21, the first rotating scraper 33, and the second rotating scraper 41 are operated for about 10 minutes in the following manner (operation a). The disk screen 21 rotates at a constant speed in the positive direction, the first rotation scraper 33 also rotates at a speed of about 1.2 times the peripheral speed of the disk screen 21 in the positive direction, and the second rotation scraper 41 also makes the first rotation in the positive direction. Rotate at a speed equal to or slightly faster than the scraper 33. The third rotation scraper 42 is stopped. In this embodiment, the positive direction means counterclockwise.

After that, the operation of the disc screen 21, the first rotation scraper 33, and the second rotation scraper 41 remains the same, and the stopped third rotation scraper 42 is rotated forward for about 0.1 seconds (operation b). Dimensional rotation means rotating in the positive direction for an extremely short time, for example, about 0.1 second. After that, the contaminant removal operation is performed while alternately repeating the a operation and the b operation.

During the contaminant removal operation, the wastewater continuously supplied is guided to the disc screen 21 via the inflow tank 15, where the contaminants in the drainage are captured by the disc screen 21 and the contaminants are removed. The drainage falls to the outflow tank 16 side and is discharged from the filtrate outflow port 14.

The contaminants captured by the disc screen 21 move to the cleaning device 31 side as the disc screen 21 rotates, and are scraped off by the first rotating scraper 33. The contaminants that have moved to the first rotation scraper 33 are further scraped off by the second rotation scraper 41 and move to the third rotation scraper 42 side. Unlike the other rotary scrapers 42, the third rotary scraper 42 is in a stopped state, so that impurities are separated from the meshing portion 48 and fall.

In this operation method, since the a operation and the b operation are alternately repeated, the meshing portion 48 between the second rotation scraper 41 and the third rotation scraper 42 can be updated. As a result, the load on the drive device 51 can be reduced.

The cleaning device 31 has a structure in which contaminants are more likely to fall as compared with the conventional cleaning apparatus, but there is a risk that contaminants may be entangled and accumulated in the meshing portion 48 with long-term operation. Therefore, after executing the contaminant removal operation for a preset time, for example, one hour, the following cleaning operation is performed to clean the meshing portion 48.

The cleaning operation is performed in a state where the drainage supply to the disc screen device 1 is stopped. After the contaminant removal operation has been performed for a preset time, the pump that supplies drainage to the disc screen device 1 is stopped. As a result, the water level of the inflow tank 15 drops. When the operation control device 61 detects that the inflow tank 15 is below the predetermined water level (step S3), the operation control device 61 controls the operations of the disc screen 21 and the cleaning device 31 as follows, and performs a cleaning operation (step S4). ..

First, the disc screen 21, the first rotation scraper 33, and the second rotation scraper 41 are rotated forward (forward) by one or more rotations (step S4-1). As a result, the impurities captured by the disc screen 21 are wiped out. Next, with the disc screen 21, the first rotation scraper 33, and the second rotation scraper 41 stopped, the third rotation scraper 42 is rotated in the normal direction (step S4-2). Dimensional rotation means rotating in the positive direction for an extremely short time, for example, about 0.1 second. The contaminants entwined with the meshing portion 48 of the second rotation scraper 41 are separated from the second rotation scraper 41 by the forward rotation.

Next, the disc screen 21 and all the rotating scrapers are reversed for about 1 second (step S4-3), and then the disc screen 21 and all the rotating scrapers are rotated forward for about 1.2 seconds (step S4-4). Subsequently, the disc screen 21 and all the rotating scrapers are reversed for about 1.5 seconds (step S4-5), and finally the disc screen 21 and all the rotating scrapers are rotated forward for about 2 seconds (step S4-6) for cleaning. End the operation.

The operation control device 61 reverses the disc screen 21 and all the rotary scrapers for about 1.5 seconds in step S4-5. At this time, the reverse command of the third rotary scraper 42 is given to the disc screen 21 and the first rotary scraper 33. It is issued with a slight delay of Δt from the reversal command of the second rotation scraper 41. This time Δt is set by the timer 71 of the operation control device 61.

The reason why the reverse rotation command of the third rotation scraper 42 is issued by using the timer 71 slightly later than the reverse rotation command of the disc screen 21, the first rotation scraper 33 and the second rotation scraper 41 is as follows.

Of the rotary scrapers, the first rotary scraper 33 and the second rotary scraper 41 are connected to the drive motor 52 via a power transmission mechanism 54 using a chain, so that they can operate even if a reverse rotation command is issued under a normal rotation state. There is a slight delay. This delay increases as the number of chains constituting the power transmission mechanism 54 increases and as the chains extend and the play increases. On the other hand, the third rotation scraper 42 has a quick response because it is driven by a dedicated drive device (not shown) directly connected to the motor.

The transition from step S4-4 to step S4-5 is from the forward rotation of the disc screen 21 and all the rotary scrapers to the reverse rotation of the disc screen 21 and all the rotary scrapers. Even if a reverse rotation command is issued to the disc screen 21 and all the rotary scrapers at the same timing in order to shift from the operation control device 61 to step S4-5, the first rotary scraper 33 and the second rotary scraper 41 have an operation delay relationship. Since then, it cannot be reversed immediately, and although it is a short time, a state of normal rotation occurs due to inertia. On the other hand, when a reverse rotation command is issued from the operation control device 61, the third rotary scraper 42 immediately reacts and starts reverse rotation.

When the second rotation scraper 41 rotates in the forward direction and the third rotation scraper 42 rotates in the reverse direction, the contaminants bite into the meshing portion 48 between the second rotation scraper 41 and the third rotation scraper 42, and the drive motor 52 and the third rotation scraper 42 The drive motor (not shown) that drives the rotary scraper 42 becomes overloaded.

In order to avoid the above state, the operation control device 61 issues a reverse rotation command of the third rotation scraper 42 with a slight time Δt delay from the reverse rotation command of the disk screen 21, the first rotation scraper 33, and the second rotation scraper 41. This time Δt may be set to the time until the first rotation scraper 33 and the second rotation scraper 41 receive the reverse rotation command and actually start the reverse rotation.

In this operation method, the timing of rotation of the rotary scraper at the time of transition from step S4-4 to step S4-5 is adjusted to prevent the contamination of contaminants, but even if the contaminants are trapped in the rotary scraper. The cleaning operation can be continued while ensuring the protection of the drive motor 52 by the safety device 56.

It is common to experience that even if the rotating scraper is temporarily bitten with contaminants, the rotating scraper is continuously rotated to remove or move the contaminants, which causes the rotating scraper to operate normally. .. By operating the safety device 56 as follows based on this rule of thumb, the cleaning operation is continued while ensuring the protection of the drive motor 52.

Since the biting of impurities into the rotary scraper is likely to occur immediately after the transition from step S4-4 to step S4-5, the operation of the timer 58 starts when the transition signal to step S4-5 is received. To do. The set time of the timer 58 is longer than the time difference Δt between the reversal command of the first rotation scraper 33 and the second rotation scraper 41 and the reversal command of the third rotation scraper 42 in step S4-5, and the operation time of step S4-5. It is set to a time shorter than that and the drive device 51 can withstand the overload condition. For example, it is set to about 0.5 to 1.0 second.

The safety device 56 starts the operation of the timer 58 immediately after receiving the transition signal from the operation control device 61 to step S4-5. When the transition from step S4-4 to step S4-5, even if the limit switch that outputs a signal to stop the drive motor 52 is turned on due to an overload state due to biting impurities, until the timer 58 times up. During that time, the drive device 51 does not stop.

If the contaminants are removed or moved by the continuation of the rotary operation of the rotary scraper before the timer 58 times out, then the rotary scraper continues to operate normally and the overload state is released. When the overload state is released, the limit switch is turned off, so that the drive device 51 does not stop after the timer 58 has timed up.

On the other hand, if the biting of contaminants cannot be released before the timer 58 times out even if the rotary operation of the rotary scraper is continued, the overload state continues and the motor 58 is driven when the time is up. A signal for stopping the motor 52 is output, and the drive motor 52 is stopped. Thereby, the drive motor 52 can be protected.

After the cleaning operation is completed, the disc screen 21 and all the rotating scrapers are in a standby state in which they are stopped. When the pump for supplying drainage to the disk screen device 1 is activated and the inflow tank 15 reaches a predetermined water level (step S1), the contaminant removal operation is executed again (step S2). This operation pattern enables stable removal of contaminants without imposing a load on the device and without performing a cleaning operation for a long time.

The operation method of the disc screen device 1 may modify the operation pattern 1 as follows. For example, in the contaminant removal operation, only operation a may be executed (operation pattern 2), and in the contaminant removal operation, the disc screen 21, the first rotation scraper 33, and the second rotation scraper 41 are rotated forward and the third rotation is performed. The scraper 42 may be rotated forward at high speed (operation pattern 3).

Next, a second operation method of the disc screen device 1 will be described. The second operating method of the disc screen device 1 shown below is an embodiment of the operating method of the disc screen device of the present invention. FIG. 8 is a flowchart showing a procedure of the operation method of the disc screen device of the present invention. The same steps as those in the first operation method of the disc screen device 1 shown in FIG. 7 are designated by the same reference numerals, and the description thereof will be omitted.

In the first operation method of the disc screen device 1 shown above, since the load on the entire equipment of the treatment facility is not high, the water supply can be stopped periodically and the cleaning operation of the cleaning device 31 can be performed. On the other hand, the second operation method of the disc screen device 1 is an operation method when the load of the entire equipment of the processing facility is high and the water supply to the disk screen device 1 cannot be stopped, and the water supply to the disk screen device 1 is performed. This is an operation method capable of cleaning the cleaning device 31 without stopping the screen.

Specifically, the cleaning device 31 is cleaned by performing a rewinding operation of the terminal rotating scraper. The terminal rotary scraper is a rotary scraper located at the end when viewed from the disc screen 21, and in the present embodiment, the third rotary scraper 42 corresponds to the rotary scraper. The rewinding operation of the end rotating scraper is mainly for cleaning the end rotating scraper and providing a new scraped surface in order to prevent a decrease in the catching rate of impurities. In the following operation method, the operation procedure is installed in the operation control device 61, and the operation control device 61 controls each operation to execute the operation.

When the operation control device 61 detects that the inflow tank 15 is above a predetermined water level in step S1, the disc screen 21 and the cleaning device 31 are operated to execute a contaminant removal operation for removing impurities in the drainage. .. In this operation method, the unwinding operation of the terminal rotary scraper shown below is integrally incorporated in this contaminant removal operation.

The contaminant removal operation is performed according to the following procedure. The disc screen 21, the first rotating scraper 33, and the second rotating scraper 41 are operated for about 10 minutes in the following manner (operation a). The disk screen 21 rotates at a constant speed in the positive direction, the first rotation scraper 33 also rotates at a speed of about 1.2 times the peripheral speed of the disk screen 21 in the positive direction, and the second rotation scraper 41 also makes the first rotation in the positive direction. Rotate at a speed equal to or slightly faster than the scraper 33. The third rotation scraper 42 is in the stopped state. In this embodiment, the positive direction means counterclockwise.

After that, the operation of the disc screen 21, the first rotation scraper 33, and the second rotation scraper 41 remains unchanged, and the stopped third rotation scraper 42 is rotated forward for about 0.1 seconds (operation b). Dimensional rotation means rotating in the positive direction for an extremely short time, for example, about 0.1 second. After that, the impurities are removed while alternately repeating the a operation and the b operation (step S2-1). The contaminant removal operation is the same as the contaminant removal operation of the first operation method.

The operation control device 61 periodically controls the operation of the disc screen 21 and the rotary scraper while controlling to perform the contaminant removal operation (step S2-1), and rewinds the following terminal rotary scraper. Drive. This rewinding operation of the end rotation scraper can be said to be an operation for collecting impurities scattered without being completely removed.

Here, the relationship between the removal of contaminants and the rewinding operation of the end rotating scraper will be described. In the contaminant removal operation in step S2-1, the third rotation scraper 42 is in the stopped state in the a operation and rotates forward in the b operation. Therefore, if the contaminant removal operation is continued without performing the cleaning operation of the cleaning device 31 at all, the contaminants gradually adhere to and accumulate on the third rotation scraper 42 as the operation is performed, and finally adhere to the third rotation scraper 42. There is a risk that the contaminants will wrap around to the back side and get caught in the part B in FIG.

The contaminants caught in part B are transferred to the second rotary scraper 41, which is transferred to the first rotary scraper 33, which is further transferred to the disc screen 21, and finally cleaned by the filtrate. Then, it flows out to the filtrate side and the capture rate of contaminants decreases. Therefore, in this operation method, the rewinding operation of the end rotating scraper is incorporated in the middle of the contaminant removal operation, the end rotating scraper is forcibly cleaned, and a new surface (scraping surface) of the end rotating scraper is provided. Prevents a decrease in the collection rate of impurities.

The specific procedure for rewinding the end rotation scraper is as follows. When a predetermined time elapses from the start of operation (step S2-2), the operation control device 61 rotates the disc screen 21 in the forward direction at high speed to forcibly lower the water level of the inflow tank 15 (step S2-3). When the operation control device 61 detects that the water level of the inflow tank 15 has dropped to a predetermined level via the level meter 17 (step S2-4), the disc screen 21 and all the rotating scrapers are immediately stopped (step S2). -5).

Next, with the disc screen 21, the first and second rotary scrapers 33 and 41 stopped, the third rotary scraper 42, which is the terminal rotary scraper, is rotated in the reverse direction (step S2-6). As a result, the contaminants adhering to the third rotation scraper 42 can be collected in the meshing portion 48 (see FIG. 6) between the third rotation scraper 42 and the second rotation scraper 41 and dropped. After that, the third rotation scraper 42 is rotated forward for about 0.1 to 0.2 seconds to provide a new surface of the third rotation scraper 42 (step S2-7).

When the rewinding operation of the end rotation scraper in steps S2-3 to S2-7 is completed, the operation control device 61 controls to return to the a operation of the contaminant removal operation in step S2-1. After that, continue operation in the same way.

The rewinding operation of the terminal rotation scraper performed during the contaminant removal operation is preferably performed until the third rotation scraper 42 makes one rotation during the contaminant removal operation, and the a operation and the b operation of the contaminant removal operation are performed several times. It may be performed after the execution (corresponding to step S2-2). By performing the rewinding operation of the terminal rotation scraper before the third rotation scraper 42 makes one rotation by the contamination removal operation, it is possible to prevent the contaminants from being caught on the back side and prevent the contamination rate from being lowered. be able to.

The time required for the rewinding operation of the end rotating scraper is short, and the water level to be lowered in step S2-3 is a water level at which the drainage does not overflow during the operations of steps S2-5 to S2-7. Good. By the above operation, the third rotating scraper 42 can be cleaned and a new surface can be provided while the water supply to the disc screen device is continued.

As described above, the operation method of the disc screen device of the present invention is a cleaning device in a state where water is continuously supplied to the disc screen device even when the load of the entire equipment of the processing facility where the disc screen device is installed is high. Since it is possible to clean the surface and provide a new scraping surface, stable operation can be performed for a long time by using this method.

Although the operation method of the disc screen device according to the present invention has been described above by the specific embodiment, the operation method of the disc screen device according to the present invention is not limited to the above embodiment.

The operation method of the disc screen device of the present invention can be said to be an operation method when the load of the entire equipment of the processing facility in which the disc screen device is installed is high and the water supply to the disc screen device cannot be stopped. Therefore, when the load of the entire equipment of the treatment facility fluctuates greatly, the operation method of the disk screen device of the present invention is carried out when the load is high, and when the load is low, the water supply is temporarily stopped. The cleaning operation of the cleaning device used in the first operation method shown in the embodiment may be performed.

In the operation method of the disc screen device of the present invention, the procedure for removing impurities is not particularly limited. Further, in the above embodiment, as the disc screen device, the disc screen device capable of preferably implementing the operation method of the disc screen device of the present invention is shown, but the disc screen device capable of implementing the operation method of the disc screen device of the present invention is described. The present invention is not limited to the above embodiment, and can be widely applied to a disc screen device having a cleaning device including a rotating scraper.

The cleaning device 31 shown in the above embodiment is composed of three rotary scrapers, but there is also a cleaning device 31 composed of two rotary scrapers or four or more rotary scrapers (for example, Japanese Patent Application Laid-Open No. 2017-35683). Issue). If the cleaning device is composed of two rotary scrapers, the second rotary scraper is the terminal rotary scraper. Similarly, if the cleaning device is composed of four rotary scrapers, the fourth rotary scraper is the terminal rotary scraper. It is assumed that the −pa corresponds to the third rotary scraper 42 of the present embodiment, and the end rotary scraper may be rewound.

In short, in a disc screen device including a cleaning device composed of n rotary scrapers (n is an integer of 2 or more), the end rotary scraper is rewound with respect to the nth rotary scraper which is the terminal rotary scraper. You just have to drive.

Although a suitable operation method of the disc screen device has been described with reference to the drawings, those skilled in the art will easily assume various changes and modifications within a self-evident range by looking at the present specification. Therefore, such changes and amendments are construed as being within the scope of the invention as defined by the claims.

1 Disc screen device 11 Casing 15 Inflow tank 17 Level meter 21 Disc screen 22 Disc 26 Rotating shaft 31 Cleaning device 33 1st rotating scraper 34 Rotating shaft 35 Comb teeth 41 2nd rotating scraper 42 3rd rotating scraper 45 Rotating shaft 46 Rotating shaft 48 Meshing part 51 Drive device 52 Drive motor 53 Power transmission mechanism 54 Power transmission mechanism 56 Safety device 57 Torque detection mechanism 58 Timer 61 Operation control device 71 Timer, timing means A Direction of meshing part

Claims (4)

A method of operating a disc screen device including an inflow tank that receives the processing liquid, a disc screen that removes impurities in the processing liquid, and a cleaning device that removes impurities adhering to the disc screen.
The cleaning device includes n or more rotary scrapers (n is an integer of 2 or more) that sequentially engage with each other to transfer and remove contaminants.
During the contaminant removal operation for continuously removing the contaminants, the end rotating scraper rewinding operation composed of the following first to third steps is performed without stopping the acceptance of the processing liquid. How to operate the disk screen device.
First step: The rotation speed of the disc screen is increased, and the water level of the inflow tank is forcibly lowered.
Second step: After the first step, the disc screen and all rotating scrapers are stopped.
Third step: After the second step, only the terminal rotating scraper is rotated to provide a new scraped surface. The rotary scraper is composed of a first rotary scraper that meshes with the disc screen, a second rotary scraper that meshes with the first rotary scraper, and a third rotary scraper that meshes with the second rotary scraper.
The terminal rotary scraper is a third rotary scraper.
The method for operating a disk screen device according to claim 1, wherein the rotation operation in the third step reversely rotates only the third rotation scraper, and then rotates the third rotation scraper in a normal direction. The method for operating a disk screen device according to claim 1 or 2, wherein the end-rotating scraper rotates forward at predetermined intervals during the contaminant removal operation. The disk screen apparatus according to any one of claims 1 to 3, wherein the rewinding operation of the terminal rotating scraper is performed until the terminal rotating scraper makes one rotation during the contaminant removal operation. How to drive.