Control device, liquid treatment system, control method, and control program

Abstract

This control device comprises a processor. The processor samples, at a predetermined cycle, the water level of a second tank that serves as a transfer destination of a liquid to be treated retained in a first tank, statistically processes water level data obtained by sampling the water level over a predetermined period, and intermittently controls a pump for transferring the liquid to be treated on the basis of the statistically processed value so that an on-time duration does not exceed a predetermined standard.

Description

Control device, liquid processing system, control method, and control program

[0001] The technology of the present disclosure relates to a control device, a liquid processing system, a control method, and a control program.

[0002] In Japanese Patent Publication No. 2016-513194, it is described that "the program installed in the delay control chip U4 is used to perform a delay control function. The specific delay control process is shown in FIG. 6. That is, when the 7-pin of the delay control chip U4 receives a low level, the 6-pin of the chip outputs a high level in the first preset time zone T1 and does not output in the second preset time zone T2. The first preset time zone T1 and the second preset time zone T2 are used as the intermittent startup cycle for the drainage pump, and in order to almost discharge the air in the working chamber of the impeller of the drainage pump, several intermittent startup cycles may be provided as necessary after the second preset time zone T2. Then, it outputs a high level in the third preset time zone T3 to officially start and operate the drainage pump. When the 7-pin of the delay control chip U4 is switched from a low level without input, the 6-pin of the chip continues to output a high level in the preset fourth time zone T4. After passing through the fourth time zone T4, the 6-pin of the delay control chip U4 does not output."

[0003] Conventionally, when transferring a liquid to be processed (referred to as "processing target liquid") from a tank at a transfer source to a tank at a transfer destination using a pump, there has been a problem that the pump becomes clogged. Also, there is a need not to deviate the water level in the tank at the transfer destination from the target water level.

[0004] Therefore, an object of the present disclosure is to provide an apparatus, a system, a method, and a program that can control the water level in the tank at the transfer destination while eliminating clogging of the pump when transferring a liquid to be processed using a pump.

[0005] A control device according to a first aspect of the present disclosure includes a processor which samples the water level of a second tank to which the liquid to be treated stored in a first tank is transferred at a predetermined period, statistically processes the sampled water level data over a predetermined period, and intermittently controls a pump that transfers the liquid to be treated so that the ON time interval does not exceed a predetermined standard based on the statistically processed value.

[0006] A control device according to a second aspect of the present disclosure, in which the processor intermittently controls the pump such that the ON time interval is shorter than the period, is in the control device according to the first aspect.

[0007] In a control device according to a third aspect of the present disclosure, in a control device according to the first or second aspect, the processor performs the sampling and statistical processing at least at the timing when the pump is turned off.

[0008] A control device according to a fourth aspect of this disclosure, in a control device according to any one of the first to third aspects, the processor performs an averaging process on the water level data.

[0009] A liquid treatment system according to a fifth aspect of this disclosure comprises the first tank, the second tank, and a control device according to any one of the first to fourth aspects.

[0010] A liquid treatment system according to a sixth aspect of the present disclosure is a liquid treatment system according to a fifth aspect, wherein the liquid to be treated is wastewater, the first tank is a wastewater adjustment tank for temporarily storing the wastewater, and the second tank is a biological treatment tank for purifying the wastewater using microorganisms.

[0011] A liquid treatment system according to a seventh aspect of this disclosure is a liquid treatment system according to a fifth or sixth aspect, wherein the second tank is provided with a device for supplying air.

[0012] A control method according to the eighth aspect of this disclosure comprises: a computer sampling the water level of a second tank to which the liquid to be treated stored in a first tank is transferred at predetermined intervals; statistically processing the sampled water level data over a predetermined period; and intermittently controlling a pump that transfers the liquid to be treated so that the ON time interval does not exceed a predetermined standard, based on the statistically processed values.

[0013] A control program according to the ninth aspect of this disclosure causes a computer to perform the following processes: sampling the water level of a second tank, to which the liquid to be treated stored in a first tank is transferred, at predetermined intervals; statistically processing the sampled water level data over a predetermined period; and intermittently controlling a pump that transfers the liquid to be treated, based on the statistically processed values, so that the ON time interval does not exceed a predetermined standard.

[0014] According to the control device, liquid processing system, control method, and control program described herein, when transferring a liquid to be processed using a pump, it is possible to control the water level in the destination tank while simultaneously clearing any blockage in the pump.

[0015] This figure shows an example of the schematic configuration of the liquid treatment system 1 according to this embodiment. This figure shows an example of the hardware configuration of the control device 100 according to this embodiment. This figure shows an example of the functional configuration of the control device 100 according to this embodiment. This figure shows an example of the operating timing of the control device 100 according to this embodiment. This figure shows a schematic configuration of a conventional liquid treatment system 1'.

[0016] Hereinafter, an example of an embodiment of the technology of this disclosure will be described with reference to the drawings. In each drawing, the same or equivalent components and parts are given the same reference numerals. Also, the dimensional ratios in the drawings may be exaggerated for illustrative purposes and may differ from the actual ratios.

[0017] For the sake of clarity, prior art will be described before disclosing this embodiment. In addition, any differences in function, configuration, or structure between this embodiment and the prior art will be distinguished by adding a "´" symbol to the reference numerals in the description of the prior art.

[0018] Figure 5 shows an example of a schematic configuration of a conventional liquid treatment system 1'. The liquid treatment system 1' comprises a first tank 10, a second tank 20, a third tank 30, and a control device 100'.

[0019] The liquid treatment system 1' may treat any liquid. Hereafter, we will explain, as an example, the case where the liquid treatment system 1' is a circulating water treatment system that biologically treats domestic wastewater and recirculates it as domestic water.

[0020] The first tank 10 is a storage tank for temporarily storing the liquid to be treated. Here, the first tank 10 is assumed to be a wastewater treatment tank for temporarily storing wastewater.

[0021] The first tank 10 is equipped with a first pump 11'. The first pump 11' is a pump for transferring the liquid to be treated from the first tank 10 to the second tank 20. Here, the first pump 11' is assumed to be a peristaltic pump for introducing wastewater into the second tank 20. A peristaltic pump is a pump that moves liquid by squeezing a soft tube such as silicone with rollers.

[0022] The second tank 20 is the destination tank for the liquid to be treated, and it treats the liquid transferred from the first tank 10. Here, the second tank 20 is assumed to be a biological treatment tank that purifies wastewater using microorganisms.

[0023] The second tank 20 is equipped with a second pump 21, a water level gauge 22, and a blower 23. The second pump 21 is a pump for transferring the liquid in the second tank 20 as treated water from the second tank 20 to the third tank 30. Here, the second pump is assumed to be a membrane filtration pump that filters the biologically treated liquid by sucking it up.

[0024] The water level gauge 22 measures the water level of the second tank 20. The water level gauge 22 may be of any type, and may be a contact type such as a pressure type, capacitive type, or float type, or a non-contact type such as a radio wave type or ultrasonic type.

[0025] Blower 23 is a device that supplies air. Here, blower 23 is assumed to be an aeration device that activates microorganisms in the second tank 20 by supplying oxygen by blowing in air. Because air is constantly supplied by blower 23, the liquid level in the second tank 20 is fluctuating. Therefore, it is important to accurately understand the water level in the second tank 20, as incorrect control of the water level will cause an overflow.

[0026] The third tank 30 is a storage tank for temporarily storing treated water. Here, the third tank 30 is assumed to be a treated water storage tank for temporarily storing treated water.

[0027] A third pump 31 is provided in the third tank 30. The third pump 31 is a pump for transferring treated water from the third tank 30 to the outside of the liquid treatment system 1'. Here, the third pump 31 is assumed to be a return pump that returns the treated water to the source of domestic wastewater as domestic water.

[0028] The control device 100' controls the entire liquid treatment system 1'. More specifically, the control device 100' may be wired or wirelessly connected to the first pump 11', the second pump 21, the water level gauge 22, the blower 23, and the third pump 31 for communication. The control device 100' may control the blower 23 to control the amount of air supplied. The control device 100' may also sample the water level measured by the water level gauge 22, and if a decrease in the water level of the second tank 20 is detected, it may control the first pump 11' to transfer the liquid to be treated from the first tank 10 to the second tank 20. The control device 100' may also control the second pump 21 to transfer the treated water from the second tank 20 to the third tank 30. The control device 100' may also control the third pump 31 to transfer the treated water from the third tank 30 to the outside.

[0029] In such a liquid treatment system 1', the control device 100' needs to accurately monitor the water level in the second tank 20 and stop the first pump 11', which is a transfer pump, when the target water level is reached. In the conventional liquid treatment system 1', a small-capacity peristaltic pump of about 200 milliliters / minute was used as the first pump 11'. As a result, the rise in the water level in the second tank 20, to which the liquid is transferred, was gradual. Furthermore, even if there were some water level fluctuations due to the blower 23, it was possible to accurately determine the water level through statistical processing.

[0030] Here, it is known that if a moving average processing method is adopted as a statistical method, a certain number of water level samples are required, and the time required for this (for example, 1 sample / second × 60 seconds = 1 minute) can be sufficiently ignored in the case of low flow rate transfers. Therefore, conventional technology allowed for accurate water level detection and stopping of the transfer pump at the appropriate timing.

[0031] However, there was a problem in that the inside of the pump tube would become clogged with highly viscous substances and debris contained in the wastewater. This problem is not limited to cases where the liquid to be treated is domestic wastewater, but can occur similarly when the liquid to be treated contains substances that cause clogging. Furthermore, this problem is not limited to cases where the first pump 11' is a peristaltic pump, but can occur similarly when the force of the first pump 11' is insufficient to push out the substances causing the clogging.

[0032] Therefore, in this embodiment, a pump capable of suction at a high flow rate is used as the transfer pump, and clogging of the pump is resolved by forcefully sucking up the liquid to be treated. Here, when a high-flow pump is used, it is clear that the second tank 20, to which the liquid is transferred, reaches the target water level in a shorter time compared to conventional technology. Furthermore, as mentioned above, it is necessary to accurately grasp the water level in the second tank 20, to which the liquid is transferred. However, for example, if water is delivered by a transfer pump of 10 liters to 100 liters / minute instead of a peristaltic pump of 200 milliliters / minute, there is a problem that accurate water level measurement is impossible because the water level changes during delivery become large.

[0033] Therefore, in this embodiment, the transfer pump is controlled intermittently to eliminate pump clogging while controlling the water level in the destination tank. This will be explained in detail.

[0034] Figure 1 shows an example of the schematic configuration of a conventional liquid treatment system 1' according to this embodiment. The differences from the conventional liquid treatment system 1' are that the first pump 11' has been changed to the first pump 11, and the control device 100' has been changed to the control device 100. Other aspects may be the same as in the conventional liquid treatment system 1', so redundant explanations will be omitted here.

[0035] The first pump 11 is a pump for transferring the liquid to be processed from the first tank 10 to the second tank 20. In this disclosure, when the term "pump" is used, it should be interpreted as referring to the "first pump 11". Examples of the type of first pump 11 include liquid transfer devices such as peristaltic pumps, diaphragm pumps, dispensers, gear pumps, and piston pumps, as well as various types of pumps for transferring large volumes of liquid, such as submersible pumps, centrifugal pumps, axial flow pumps, and turbine pumps.

[0036] In this embodiment, it is preferable to use a particularly large-capacity liquid transfer device as the first pump 11. Here, "large capacity" means a capacity that is relatively larger than the first pump 11' used in the conventional liquid processing system 1'. Specifically, for example, a capacity of about 10 liters / min to 100 liters / min is preferable because it can suction with sufficient force to clear the blockage in the pump.

[0037] For the purposes of this explanation, we will describe the case in which a submersible pump is used as the first pump 11. Therefore, in this figure, the first pump 11 is shown submerged in the liquid to be treated stored in the first tank 10.

[0038] The control device 100 controls the entire liquid treatment system 1. More specifically, the control device 100 may be connected to the first pump 11, the second pump 21, the water level gauge 22, the blower 23, and the third pump 31 via wired or wireless means for communication. The control device 100 may control the amount of air supplied by controlling the blower 23. The control device 100 may also sample the water level measured by the water level gauge 22, and if a decrease in the water level of the second tank 20 is detected, it may intermittently control the first pump 11 to transfer the liquid to be treated from the first tank 10 to the second tank 20. The control device 100 may also control the second pump 21 to transfer the treated water from the second tank 20 to the third tank 30. The control device 100 may also control the third pump 31 to transfer the treated water from the third tank 30 to the outside.

[0039] Figure 2 shows an example of the hardware configuration of the control device 100 according to this embodiment. The control device 100 includes a processor 101, a ROM (Read Only Memory) 102, a RAM (Random Access Memory) 103, a storage 104, a communication interface 105, and a user interface 106. These components are connected to each other via a bus 109 so that they can communicate with one another.

[0040] The processor 101 executes various programs and controls each component. Here, the processor 101 is assumed to be a CPU (Central Processing Unit). The ROM 102 stores various programs and data. The RAM 103 temporarily stores programs or data as a working area. The storage 104 consists of an HDD (Hard Disk Drive) or SSD (Solid State Drive) and stores various programs and data, including the operating system.

[0041] In the control device 100 according to this embodiment, the control program 107 is stored in the ROM 102 or storage 104. In this figure, the case in which the control program 107 is stored in the storage 104 is shown as an example. The processor 101 reads the control program 107 from the ROM 102 or storage 104 and executes it using the RAM 103 as a working area, thereby performing control of each configuration and various calculation processes according to the control program 107.

[0042] The communication interface 105 is an interface for the control device 100 to communicate with other devices. The user interface 106 is an input / output interface for the control device 100 to exchange information with a user. The user interface 106 may include input devices such as a mouse, keyboard, touch panel, and microphone, and output devices such as a monitor and speakers.

[0043] Figure 3 shows an example of the functional configuration of the control device 100 according to this embodiment. The control device 100 comprises a sampling unit 110, a statistical processing unit 120, and a control unit 130. These functional configurations may be implemented in the processor 101 by the processor 101 reading the control program 107 from the ROM 102 or storage 104, expanding it into the RAM 103, and executing it.

[0044] The sampling unit 110 samples the water level of the second tank 20 at a predetermined period. As an example, the sampling unit 110 may sample the water level of the second tank 20 measured by the water level gauge 22 at a rate of 1 sample / second.

[0045] The statistical processing unit 120 performs statistical processing on the water level data obtained by sampling the water level over a predetermined period. Hereinafter, the case where the statistical processing unit 120 performs averaging processing on the water level data will be described as an example. Examples of such averaging processing include moving averaging processing and approximation processing (smoothing processing). As an example, the statistical processing unit 120 may perform moving averaging processing on the water level data sampled every second for 60 seconds.

[0046] The control unit 130 intermittently controls the first pump 11 based on the statistically processed value so that the on-time width does not exceed a predetermined standard.

[0047] FIG. 4 is a diagram showing an example of the operation timing of the control device 100 according to the present embodiment. In this figure, the horizontal axis represents time, and the sampling timing, statistical processing timing, and intermittent control timing are shown from top to bottom, respectively.

[0048] In this figure, an example of the operation timing is shown when the sampling period (predetermined period) is 1 second, the target period for moving averaging processing (predetermined period) is 60 seconds, the on-time width is 3 seconds, and the off-time width is 57 seconds. In addition, at the statistical processing timing shown in the center of this figure, three cases are illustrated to explain that a predetermined period starting from various time points can be used as the target period for moving averaging processing. However, it is more preferable to perform moving averaging processing on the water level data in a predetermined period (that is, the predetermined period shown by the solid line in this figure) from the timing when the first pump 11 can be switched from off to on to the timing when the first pump 11 can be switched from off to on next (that is, times T01 to T11, times T11 to T21, and times T21 to T31, etc. in this figure).

[0049] As shown in this figure, the processor 101 may intermittently control the first pump 11 so that the ON time interval is shorter than a predetermined period. Also, as shown in this figure, the processor 101 may perform sampling and statistical processing at least when the first pump 11 is turned off. This will be explained in detail.

[0050] The processor 101 controls the water supply timing based on the water level of the second tank 20, which is determined from statistically processed water level data (e.g., a moving average). In this case, the number of times the first pump 11 supplies water is determined based on the previous water level. The ON time interval of the first pump 11 may be fixed or variable. Here, it is assumed that the ON time interval is fixed at 3 seconds.

[0051] In this situation, suppose the moving average value from time T01 to time T11 indicates that the water level in the second tank 20 is lower than the target water level. In this case, the processor 101 decides to turn on the first pump 11 at time T11 and starts operating the first pump 11. As a result, the first pump 11 is on for 3 seconds from time T11 to time T12, and then off for 57 seconds from time T12 to time T21. Next, suppose the moving average value from time T11 to time T21 indicates that the water level in the second tank 20 is still lower than the target water level. In this case, the processor 101 decides to turn on the first pump 11 at time T21 and starts operating the first pump 11. As a result, the first pump 11 is on for 3 seconds from time T21 to time T22, and then off for 57 seconds from time T22 to time T31. Next, suppose the moving average value from time T21 to time T31 indicates that the water level in the second tank 20 is still lower than the target water level. In this case, the processor 101 decides to turn on the first pump 11 at time T31 and starts operating the first pump 11. As a result, the first pump 11 is on for 3 seconds from time T31 to T32, and then off for 57 seconds from time T32 to time T41 (not shown). Next, suppose the moving average value from time T31 to time T41 indicates that the water level in the second tank 20 has reached the target water level. In this case, the processor 101 decides not to turn on the first pump 11 at time T41. As a result, the processor 101 intermittently controls the first pump 11 three times.

[0052] The processor 101 controls the water level in the second tank 20 by controlling the operating time of the first pump 11, for example, as shown above. In this case, the processor 101 does not take into account the capacity of the first pump 11. By designing the system to be independent of the capacity of the pump used in this way, water level control can be achieved without using a flow meter.

[0053] Here, the processor 101 limits the amount transferred at one time and transfers it in stages in multiple stages, which means that the transfer takes longer compared to when the amount transferred at one time is not limited. However, when the second tank 20 to which the transfer is made is a biological treatment tank, it is known that purification using microorganisms takes time in the first place. Therefore, even if the liquid to be treated is transferred in stages little by little as in this embodiment, the liquid treatment system 1 as a whole does not lose any time. Accordingly, the technology of this embodiment is particularly well-suited to liquid treatment systems 1 that involve biological treatment.

[0054] Even when the first pump 11 is controlled intermittently in this manner, the processor 101 can perform sampling and averaging processing regardless of the timing of the intermittent control. That is, the processor 101 continues sampling and averaging processing not only when the first pump 11 is turned on, but also when the first pump 11 is turned off. This allows for a sufficient pump stop period before the next transfer, and this period can be used for sampling and averaging of the water level. Therefore, accurate water level detection becomes possible with a sufficient sampling period, and deviations from the target water level can be suppressed.

[0055] In the above explanation, the case in which sampling and averaging processing are performed at the timing when the first pump 11 is turned on was shown as an example. However, at the timing when the first pump 11 is turned on, the liquid level in the second tank 20, which is the destination for the transfer, may be rippling. This can become more pronounced as the capacity of the first pump 11 increases.

[0056] Therefore, the processor 101 does not need to sample the water level of the second tank 20 when the first pump 11 is turned on. The processor 101 may also exclude the sample value at the time the first pump 11 is turned on and perform the averaging process. In other words, the processor 101 only needs to perform sampling and statistical processing at least when the first pump 11 is turned off.

[0057] However, this is not the only option. Performing sampling and statistical processing at the time the first pump 11 turns off is not an essential configuration in this embodiment, and this does not preclude performing sampling and statistical processing only at the time the first pump 11 turns on.

[0058] As an alternative to this embodiment, it is also conceivable to control the first pump 11 based on instantaneous sample values ​​without performing an averaging process. However, with this approach, it was not possible to accurately stop the operation of the first pump 11, resulting in the water level in the second tank 20 deviating significantly from the target water level.

[0059] Another approach involves shortening the sampling period to obtain multiple samples in a short time and then performing an averaging process. However, this approach resulted in the inability to obtain accurate water levels because the period of water level fluctuations is longer than the sampling period.

[0060] Therefore, based on these results, in this embodiment, we decided to adopt a method of limiting the amount transferred at one time and transferring it in multiple steps.

[0061] As described above, the control device 100 according to this embodiment samples the water level of the second tank 20 at a predetermined period, statistically processes the sampled water level data over a predetermined period, and intermittently controls the transfer pump based on the statistically processed value so that the ON time interval does not exceed a predetermined standard. As a result, the control device 100 according to this embodiment can control the water level in the destination tank while eliminating pump clogging. Cases in which it is difficult to grasp the liquid level include when the amount of transfer per unit time is large, when waves occur due to water supply at the destination (i.e., water supply by the second pump 21), and when waves occur due to aeration at the destination (i.e., air supply by the blower 23). The control device 100 according to this embodiment can accurately grasp the water level and appropriately control the amount of transfer in any of these cases.

[0062] The processes described above can also be implemented using dedicated hardware circuits. In this case, the process may be executed on a single piece of hardware or on multiple pieces of hardware.

[0063] Furthermore, in the above explanation, the term "processor" refers to a broad type of processor, including general-purpose processors (e.g., CPU: Central Processing Unit, etc.) and specialized processors (e.g., GPU: Graphics Processing Unit, ASIC: Application Specific Integrated Circuit, FPGA: Field Programmable Gate Array, Programmable Logical Device, etc.).

[0064] Furthermore, the processor operations described above may not be performed by a single processor, but may also be performed by multiple processors located in physically separate locations working together. Also, the order of the processor operations is not limited to the order described above and may be changed as appropriate.

[0065] Furthermore, the aforementioned program may be provided on a computer-readable non-temporary recording medium such as a USB (Universal Serial Bus) memory, flexible disk, or CD-ROM (Compact Disc Read Only Memory), or it may be provided online via a network such as the Internet. In this case, the program recorded on the computer-readable non-temporary recording medium is usually transferred to and stored in memory or storage. This program may also be provided, for example, as a standalone application software, or it may be incorporated into the software of each device as a function of that device.

[0066] Furthermore, the aforementioned program can be provided as a program product. A program product includes any form of product for providing a program. For example, a program product includes a program provided via a network such as the Internet, and non-temporary computer-readable recording media such as CD-ROMs and DVDs on which the program is stored.

[0067] This disclosure is not limited to the foregoing, and it goes without saying that it can be implemented in various modified forms without departing from its intent.

[0068] The disclosure of Japanese Patent Application No. 2024-207695, filed on 28 November 2024, is incorporated herein by reference in its entirety. Furthermore, all documents, patent applications, and technical standards described herein are incorporated herein by reference to the same extent as if the incorporation of each individual document, patent application, and technical standard were specifically and individually noted.

Claims

1. A control device comprising a processor, the processor sampling the water level of a second tank to which the liquid to be treated stored in a first tank is transferred at predetermined intervals, statistically processing the sampled water level data over a predetermined period, and intermittently controlling a pump that transfers the liquid to be treated so that the ON time interval does not exceed a predetermined standard based on the statistically processed values.

2. The control device according to claim 1, wherein the processor intermittently controls the pump such that the ON time interval is shorter than the period.

3. The control device according to claim 2, wherein the processor performs the sampling and statistical processing at least at the timing when the pump is turned off.

4. The control device according to claim 1, wherein the processor performs an averaging process on the water level data.

5. A liquid treatment system comprising the first tank, the second tank, and the control device according to any one of claims 1 to 4.

6. The liquid treatment system according to claim 5, wherein the liquid to be treated is wastewater, the first tank is a wastewater adjustment tank for temporarily storing the wastewater, and the second tank is a biological treatment tank for purifying the wastewater using microorganisms.

7. The liquid treatment system according to claim 6, wherein the second tank is provided with a device for supplying air.

8. A control method comprising: a computer sampling the water level of a second tank, to which the liquid to be treated stored in a first tank is transferred, at predetermined intervals; statistically processing the sampled water level data over a predetermined period; and intermittently controlling a pump that transfers the liquid to be treated, based on the statistically processed values, so that the ON time interval does not exceed a predetermined standard.

9. A control program that causes a computer to perform the following processes: sampling the water level of a second tank, to which the liquid to be treated stored in a first tank is transferred, at predetermined intervals; statistically processing the sampled water level data over a predetermined period; and intermittently controlling a pump that transfers the liquid to be treated, based on the statistically processed values, so that the ON time interval does not exceed a predetermined standard.

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