JP2015112507A - Interface control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an interface control method which is used for appropriately controlling a position of the interface between a suspended solid matter layer and a liquid layer in a flotation tank.SOLUTION: The interface control method, which is used for controlling the position of the interface between the suspended solid matter layer and the liquid layer in the flotation tank (20) of a floatation type solid-liquid separation apparatus (10), comprises: an image pickup step of taking an image of a window part (22b) which is arranged on the side wall (22a) of the flotation tank and through which the light from the inside of the flotation tank can be transmitted; an information acquisition step of processing the taken image to acquire the positional information on the position of the interface; and adjustment step of adjusting at least one of a feed rate of the raw water to the flotation tank, a discharge rate of the treated water from the flotation tank, and another discharge rate of the suspended solid matter on the basis of the acquired positional information.

Description

  The present invention relates to an interface control method for controlling the position of an interface between a floating solid content layer and a liquid layer in a floating tank of a floating solid-liquid separator.

  In a wastewater treatment process of a plant or the like, a floating solid-liquid separator may be used as a solid-liquid separator for removing solid content (floating matter) in raw water. As a floating solid-liquid separation device, for example, fine water bubbles are generated by opening raw water in which supersaturated air is dissolved by pressurization in a pipe to a floating tank, and solids (floating matter) are floated and formed There is a pressurized flotation device that separates raw water into a floating solid content layer and a liquid layer.

  The floating solid-liquid separation device is small in size because it can separate the solid content in the raw water in a shorter time than a solid-liquid separation device of the type that settles the solid content (see Patent Document 1, etc.). However, it is possible to realize a solid-liquid separation device with high processing capacity. On the other hand, a floating solid-liquid separation device that can process a large amount of raw water in a small floating tank tends to fluctuate the position of the interface between the floating solid content layer and the liquid layer. In order to realize this, it is desirable to control the position of the interface within a predetermined range. This is because if the interface position rises too much, the discharged solids will contain excessive moisture, and conversely if the interface position falls too much, the solids will be mixed in the discharged processing liquid. This is because the subsequent processing efficiency is adversely affected.

JP 7-280623 A

  In a solid-liquid separation device of the type that settles the solid content, for example, by using an optical sensor or the like installed above the sedimentation tank, the solid content is received by receiving light reflected from the surface of the sedimented solid content layer. It is possible to detect the position of the interface between the layer and the liquid layer. At this time, since the supernatant water formed on the surface portion of the settling tank easily transmits light, detection of the position of the interface by the sensor disposed above is not hindered. However, in the floating solid-liquid separator, an opaque floating solid content layer is formed on the surface of the floating tank, so that the position of the interface between the floating solid content layer and the liquid layer can be detected from above or It is difficult to see. Further, in the case of the conventional technique in which the position of the interface is adjusted by an operation by the operator, it is necessary for the operator to monitor and operate the apparatus constantly or frequently in order to cope with the position of the interface that is likely to fluctuate.

  This invention is made | formed in view of such a situation, The objective is to provide the interface control method which controls appropriately the position of the interface of a floating solid content layer and a liquid layer in a floating tank.

In order to achieve the above object, the interface control method according to the present invention comprises:
An interface control method for controlling the position of an interface between a floating solid content layer and a liquid layer in a floating tank of a floating solid-liquid separator,
An imaging step of taking an image of a window portion provided on the side wall of the levitation tank and capable of transmitting light from the inside of the levitation tank;
An information acquisition step of performing image processing on the image and acquiring position information regarding the position of the interface;
An adjustment step of adjusting at least one of a raw water inflow speed to the levitation tank, a treated water discharge speed from the levitation tank, and a floating solid content discharge speed from the levitation tank based on the position information.

  The interface control method according to the present invention captures an image of a window provided on the side wall of the levitation tank, and performs image processing to accurately detect the interface that was difficult to detect with a sensor or the like installed above the tank. Position information can be acquired. Moreover, the position of the interface can be suitably controlled by adjusting the raw water inflow rate, the treated water discharge rate, the floating solid content discharge rate, and the like using the acquired position information.

  Further, for example, in the adjustment step, the opening amount of the inflow valve that changes the raw water inflow rate into the levitation tank and the opening amount of the discharge valve that changes the treated water discharge speed from the levitation tank may be adjusted.

  By adjusting the opening amount of the inflow valve and the opening amount of the discharge valve, the raw water inflow speed to the levitation tank and the treated water discharge speed from the levitation tank can be accurately controlled. The position of the interface can be controlled with higher accuracy.

Further, for example, a circulation process including the imaging process, the information acquisition process, and the adjustment process may be performed at a predetermined circulation cycle,
When the circulation process in which the position information cannot be acquired in the information acquisition process continues two or more predetermined times, a warning process with a warning display or a warning sound may be performed.

  When the imaging process is performed at the timing when the revolving member for discharging the floating solids and treated water passes through the window, the position of the interface is recognized in the information acquisition process due to the influence of the inside of the floating tank being stirred. There are cases where it is not possible. Therefore, when the position information cannot be acquired in one information acquisition process, the warning process is not performed, and the warning process is performed when the position information cannot be acquired for a predetermined number of times two or more. Can be warned correctly.

Further, for example, a circulation process including the imaging process, the information acquisition process, and the adjustment process may be performed at a predetermined circulation cycle,
The circulation period may be a natural number times the revolution period of the revolution member that circulates in the levitation tank.

  By making the circulation cycle a natural number times the revolution cycle, it is possible to always synchronize the image acquisition timing with the timing at which the revolution member is not easily affected by agitation caused by passing near the window. Accurate position information can be obtained.

FIG. 1 is a schematic perspective view of a floating solid-liquid separator. FIG. 2 is a schematic top view and a schematic sectional view from the side of the floating solid-liquid separator. FIG. 3 is a block diagram of a floating solid-liquid separator. FIG. 4 is a flowchart showing an interface control method according to an embodiment of the present invention. FIG. 5 is a flowchart showing an interface control method according to a modification. FIG. 6 is a conceptual diagram illustrating a display example using a display monitor.

  FIG. 1 is a schematic perspective view of a floating solid-liquid separation apparatus 10 that performs an interface control method according to an embodiment of the present invention. The floating solid-liquid separation apparatus 10 includes a floating tank 20 for forming a floating solid component layer and a liquid layer to separate solid components (floating matter) in raw water, and a floating component forming a floating solid component layer. Floating solid content discharging means 30 as a floating solid content discharging means for scraping and removing solid content (scum) from the floating tank 20, an imaging unit 60 for capturing an image in the vicinity of the interface between the floating solid content layer and the liquid layer, etc. Have

  The floating tank 20 is a top open type circular in plan view, and is a ring-shaped region formed between the internal rotation ring 24 disposed in the center and the side wall 22a constituting the outer peripheral side wall of the floating tank 20. In addition, raw water to be treated is stored. A window 22b that can transmit light from the inside of the floating tank 20 is formed on the side wall 22a, and the imaging unit 60 is disposed at a position facing the window 22b. Tempered glass or the like can be used for the material of the window 22b, and the floating tank 20 other than the window 22b is made of stainless steel or the like, but the material of the floating tank 20 is not particularly limited.

  FIG. 2A is a schematic plan view of the floating solid-liquid separator 10, and FIG. 2B is a schematic cross-sectional view of the floating solid-liquid separator 10. As shown in FIG. 2 (b), a raw water inlet 42 is formed at the center bottom of the levitation tank 20, and the raw water to be treated passes through the raw water inflow path 40 from the raw water inlet 42 and floats. It flows into the water storage area of the tank 20. The raw water inlet 42 is connected to the raw water inflow valve 52, and the amount of raw water flowing into the levitation tank 20 is adjusted by the amount of opening of the raw water inflow valve 52.

  The floating solid content discharge means 30 is provided to rotate (revolve) while rotating on the upper part of the floating tank 20 by a revolving drive means and a rotation drive means (not shown) to form a floating solid content layer. Scoop off floating solids. The floating solid content scooped up by the floating solid content discharge means 30 flows into the internal fixed tank 44 provided at the center of the floating tank 20 and from the floating solid content discharge port 46 formed at the bottom of the internal fixed tank 44. Discharged.

  In the vicinity of the bottom of the floating tank 20, four waste water outlet ducts 35 are provided as treated water discharge means. The waste water outlet duct 35 is provided so as to circulate (revolve) in the vicinity of the bottom of the floating tank 20 by a revolving drive means (not shown), and discharges treated water constituting the liquid layer from which the solid content has been separated. The treated water flows into the region inside the internal rotary ring 24 through the waste water outlet duct 35 and is discharged from the treated water outlet 28 formed at the bottom of the floating tank 20 over the overflow ring 27. The treated water outlet 28 is connected to the treated water discharge valve 54, and the discharged amount of treated water is adjusted by the open amount of the treated water discharge valve 54.

  A sludge outlet 26 for discharging the precipitated sludge is formed at the bottom of the floating tank 20, and the sludge can be discharged by opening the sludge discharge valve 56 connected to the sludge outlet 26. However, the sludge discharge valve 56 is closed during normal operation.

  FIG. 3 is a block diagram showing a configuration related to the interface control method in the floating solid-liquid separator 10. The imaging unit 60 that captures an image of the window 22b from the outside of the floating tank 20 includes an optical lens and a solid-state imaging device, and outputs the acquired image of the window 22b to the image processing controller 63. The image processing controller 63 performs image processing on the image of the window portion 22b imaged by the imaging unit 60, and acquires position information regarding the position of the interface between the floating solid content layer and the liquid layer. The interface position information acquired by the image processing controller 63 is output to the display monitor 67 and the main body control unit 70. For example, the image processing controller 63 can analyze the luminance, lightness, saturation, hue, and the like of each pixel included in the image, and acquire interface position information.

  The illumination 62 is composed of, for example, an LED or the like, and illuminates the window portion 22b when necessary at night or the like. The lighting controller 64 controls lighting and extinguishing of the lighting 62 and brightness at the time of lighting. The display monitor 67 displays the image of the window 22 b acquired by the imaging unit 60 and the position information of the interface calculated by the image processing controller 63. The operation console 68 is a user interface for the operator to send commands to the image processing controller 63 and the illumination controller 64. The operator can set an image processing condition in the image processing controller 63, an output condition to the display monitor 67, a lighting condition of the illumination 62, and the like using the operation console 68. The power supply 65 supplies power to each component related to image processing, such as the imaging unit 60, the illumination 62, and the image processing controller 63.

  Based on the interface position information acquired by the image processing controller 63, the main body controller 70 feeds the raw water into the levitation tank 20, the treated water discharge speed from the levitation tank 20, and the floating solid content discharge speed from the levitation tank 20. To control. Specifically, the main body control unit 70 outputs a control signal to the inflow valve driving unit 72 and the discharge valve driving unit 74 and the floating solid content discharging unit driving unit 76 that drives the floating solid content discharging unit 30, and the valve 52. , 54 and the rotation and revolution speed of the floating solid content discharging means 30 are maintained or changed. The inflow valve driving unit 72 and the discharge valve driving unit 74 are configured to operate with a pressure such as air, and drive the raw water inflow valve 52 and the treated water discharge valve 54 with a pressure such as air. The floating solid content discharging means driving unit 76 is constituted by a rotating motor or the like, and causes the floating solid content discharging means 30 to rotate and revolve.

  FIG. 4 is a flowchart showing an interface control method according to an embodiment of the present invention. Hereinafter, a specific interface control method will be described with reference to FIG.

  In step S001 of FIG. 4, the raw water inflow valve 52 of the floating solid-liquid separator 10 is opened, and the inflow of raw water into the floating tank 20 is started. In the raw water, air is dissolved in a supersaturated state by pressurization in the pipe, and when the raw water is opened to the water storage area of the levitation tank 20, fine bubbles are generated and the solid content is levitated. A floating solid content layer and a liquid layer are formed.

  In step S002, the floating solid content discharging means 30 starts discharging the floating solid content. The floating solid content discharging means 30 performs a revolving motion with the central portion of the floating tank 20 as the rotational center while performing a rotational motion with the axis extending in the substantially horizontal direction as the rotational center axis. The floating solid content discharging means 30 discharges the floating solid content while circling the upper part of the floating tank 20 by revolving while scraping the floating solid content constituting the floating tank 20 by the rotation motion. As shown in FIG. 2, the floating solid content scraped off by the floating solid content discharging means 30 is poured into an internal fixed tank 44 disposed at the center of the main body tank 22 and discharged from the floating solid content discharge port 46. The

In step S003, the discharge of the treated water from which the solid content has been removed from the raw water is started via the waste water outlet duct 35 and the treated water discharge valve 54. As shown in FIG. 2, the treated water flows into the treated water outlet 28 via the wastewater outlet duct 35 that performs a revolving motion with the center of the floating tank 20 as the center of rotation. In this state, the treated water discharge valve 54 connected to the treated water outlet 28 is opened to start the treatment water discharge.
The floating solid-liquid separation device 10 has two revolution members, the floating solid content discharge means 30 and the waste water outlet duct 35. In this embodiment, the floating solid content discharge means 30 and the waste water outlet duct 35 revolve. Although the period is the same, the embodiment of the present invention is not limited to this, and the two revolution members may circulate at different revolution periods.

  In step S004, the imaging unit 60 acquires an image of the window 22b. When the periphery of the window 22b is dark at the time of imaging, the illumination controller 64 turns on the illumination 62 and adjusts the brightness of the acquired image (see FIG. 3). The image acquired by the imaging unit 60 is output to the image processing controller 63.

  In step S005, the image processing controller 63 performs image processing on the image acquired by the imaging unit 60, and acquires position information regarding the position of the interface between the floating solid content layer and the liquid layer. The acquired position information is output to the main body control unit 70 and is output to the display monitor 67 together with the image.

  FIG. 6 illustrates a display example of the display monitor 67. In the display example illustrated in FIG. 6A, the image 82 captured by the imaging unit 60 in step S004 is the position of the interface acquired in step S005. It is displayed together with information (arrow 84). For example, when the floating solid content layer easily reflects light, the image 82 is a bright region, and the liquid layer is a dark region. As indicated by an arrow 84, in step S005, the image processing controller 63 can detect the boundary between the bright area and the dark area in the image 82 as the interface position between the floating solid content layer and the liquid layer.

  In step S006, the main body control unit 70 shown in FIG. 3 uses the raw water inflow speed to the levitation tank 20, the treated water discharge speed from the levitation tank 20, and the levitation tank 20 based on the positional information on the interface acquired in step S005. Adjust the floating solids discharge speed. For example, when the position of the interface is lower than the reference position, the main body control unit 70 drives the inflow valve driving unit 72 to increase the opening amount of the raw water inflow valve 52 to increase the raw water inflow speed or the discharge valve driving unit 74. The position of the interface can be raised by reducing the opening amount of the treated water discharge valve 54 to reduce the treated water discharge speed.

  For example, as shown in FIG. 6A, when the interface position (arrow 84) is higher than the reference position 90, the main body control unit 70 drives the inflow valve driving unit 72 to open the raw water inflow valve 52. Decrease the amount, reduce the raw water inflow speed, or drive the discharge valve drive unit 74 to increase the open amount of the treated water discharge valve 54, increase the treated water discharge speed, lower the interface position Can be made. In addition, the main body control unit 70 drives the floating solid content discharge means driving unit 76 to change the rotation / revolution speed of the floating solid content discharge means 30 to change the floating solid content discharge speed, The upper surface position of the floating solid content layer can be controlled.

  After the adjustment operation in step S006, the process returns to step S004, and the circulation process including the imaging process (step S004), the information acquisition process (step S005), and the adjustment process (step S006) is repeated at a predetermined circulation period. The circulation cycle of the circulation process including steps S004 to S006 is not particularly limited, but is preferably a natural number times the revolution cycle of the floating solid content discharge means 30 or the wastewater outlet duct 35 that circulates in the floating tank 20, for example, More preferably, the solid content discharging means 30 or the waste water outlet duct 35 is set to 1 or 2 times the revolution period. Thereby, the timing of the imaging process (step S004) is always synchronized with the timing at which the floating solid component layer and the liquid layer are appropriately separated after a predetermined time has passed after the revolving member passes near the window 22b. Can be made.

  For example, as shown in FIG. 6B, when the position of the interface (arrow 86) calculated from the image 85 is more than a predetermined distance from the reference position 90, the image processing controller before and after step S006. 63 may perform a warning process in which a warning display 92 is displayed on the display monitor 67.

  As described above, according to the interface control method of the present invention, the image of the window portion 22b provided on the side wall portion 22a of the levitation tank 20 is picked up, and this is subjected to image processing, thereby providing a sensor installed above the tank. Then, it is possible to obtain accurate position information of the interface which was difficult to detect. Moreover, the position of the interface can be suitably controlled by adjusting the raw water inflow rate, the treated water discharge rate, the floating solid content discharge rate, and the like using the acquired position information. In particular, the position of the interface can be controlled more accurately by adjusting the opening amounts of the raw water inflow valve 52 and the treated water discharge valve 54.

  The interface control method according to the present invention is not limited to the embodiment shown in the flowchart of FIG. 4 and includes various modifications. FIG. 5 is a flowchart showing an interface control method according to a modification of the present invention. Hereinafter, the interface control method according to the modification will be described with reference to FIG.

Steps S101 to S104 shown in FIG. 5 are the same processes as steps S001 to S004 in FIG.
In step S105 illustrated in FIG. 5, the image processing controller 63 performs image processing on the image acquired by the imaging unit 60, and acquires position information regarding the position of the interface between the floating solid content layer and the liquid layer. When the image processing controller 63 can recognize the position of the interface, the image processing controller 63 outputs position information including the position of the interface to the main body control unit 70 and the display monitor 66. On the contrary, when the image processing controller 63 cannot recognize the position of the interface, the image processing controller 63 outputs the fact as position information to the main body control unit 70 and outputs the image to the display monitor 67.

  FIG. 6C is a display example when the position of the interface cannot be recognized in step S105. The image 88 is acquired when the imaging step (step S104) is performed immediately after a revolving member such as the floating solid content discharge means 30 or the waste water outlet duct 35 passes near the window 22b. In the image 88, the floating solid content layer and the liquid layer are mixed by stirring by the revolving member, and the image processing controller 63 cannot recognize the position of the interface from the image 88.

  In step S106, the main body control unit 70 shown in FIG. 3 determines whether interface position information has been acquired in step S105. If the interface position cannot be recognized in step S105, the process proceeds to step S107.

  In step S107, it is determined whether or not the circulation process in which it is determined in step S106 that the position of the interface cannot be acquired continues two or more predetermined times, retroactively from the current circulation process. In the case where the circulation process in which it is determined in step S106 that the interface position cannot be acquired does not continue for a predetermined number of times, for example, the interface position information has been acquired in step S106 in the previous circulation process (previous step S106). In such a case, the warning operation is not performed and the process proceeds to step S104. On the other hand, if step S106 in which it has been determined that the position of the interface has not been acquired has occurred continuously a predetermined number of times or more retroactively from the present time, the process proceeds to step S109 and a warning process is performed. To do.

  In step S109, a warning process is performed such that the display monitor 67 displays a warning display 94 as shown in FIG. 6C, or a warning sound is generated by an alarm device (not shown). After step S109, the process proceeds to step S104.

If the interface position can be recognized in step S106, the process proceeds to step S108.
In step S108, it is determined whether or not the interface position (x) is within a predetermined range (lower limit value a and upper limit value b or less), and if the interface position (x) is not within the predetermined range. Then, the process proceeds to step S110, and an adjustment process for adjusting the position of the interface is performed. Since the adjustment process performed in step S110 is the same as that in step S006, description thereof is omitted. After completion of step S110, the process proceeds to step S104.

If it is determined in step S108 that the interface position (x) is within the predetermined range, the process proceeds to step S104 without performing the adjustment process.
Thereafter, similarly, the circulation process including steps S104 to S110 is repeated at a predetermined circulation cycle.

  According to the interface control method according to the modified example, even if the position information cannot be acquired in the information acquisition process, the warning process is not performed for the first time, and the position information cannot be acquired for a predetermined number of times two or more times. By performing the above, it is possible to correctly warn of a device abnormality. Even if the device is operating normally, if the imaging process (step S104) is performed at the timing when the revolving member passes through the window 22b, the information acquisition process ( This is because the interface position may not be recognized in step S105).

  Further, by performing the adjustment process only when the detected interface position (x) is not within the predetermined range (a or more and b or less), the adjustment process is performed in response to a slight change in the interface position. This can be prevented and stable interface position control can be realized.

DESCRIPTION OF SYMBOLS 10 ... Floating type solid-liquid separator 20 ... Flotation tank 22b ... Window part 30 ... Flotation solid content discharge means 35 ... Waste water outlet duct (process water discharge means)
44 ... Internal fixed tank 46 ... Floating solid content discharge port 52 ... Raw water inflow valve 54 ... Process water discharge valve 56 ... Sludge discharge valve 60 ... Imaging unit 63 ... Image processing controller 70 ... Main body control unit

Claims (4)

An interface control method for controlling the position of an interface between a floating solid content layer and a liquid layer in a floating tank of a floating solid-liquid separator,
An imaging step of taking an image of a window portion provided on the side wall of the levitation tank and capable of transmitting light from the inside of the levitation tank;
An information acquisition step of performing image processing on the image and acquiring position information regarding the position of the interface;
An adjustment step of adjusting at least one of the raw water inflow rate to the levitation tank, the treated water discharge speed from the levitation tank, and the floating solid content discharge speed from the levitation tank based on the position information. Control method.   2. The adjusting step adjusts an opening amount of an inflow valve that changes a raw water inflow speed to the levitation tank and an opening amount of a discharge valve that changes a discharge speed of treated water from the levitation tank. The interface control method described in 1. A circulation process including the imaging process, the information acquisition process, and the adjustment process is performed at a predetermined circulation cycle,
The warning process with warning display or warning sound is performed when the circulation process in which the position information cannot be acquired in the information acquisition process continues two or more predetermined times. Interface control method. A circulation process including the imaging process, the information acquisition process, and the adjustment process is performed at a predetermined circulation cycle,
The interface control method according to any one of claims 1 to 3, wherein the circulation cycle is a natural number times the revolution cycle of the revolution member that circulates in the levitation tank.

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