Water storage tanks, circulating water treatment equipment

Abstract

To accurately measure a water level of water containing impurities including microorganisms that may form a biofilm.SOLUTION: A water level sensor includes a first electrode, a second electrode, and a control part. The first electrode is installed at a first height in a tank for storing water containing impurities including microorganisms that may form a biofilm. The second electrode is installed at a second height higher than the first height, in the tank. When water comes into contact with the first electrode and the second electrode, the control part detects that the water has reached the second height.SELECTED DRAWING: Figure 6

Description

Technical Field

[0001] The present disclosure relates to a water level sensor, a water storage tank, a hand washing device, and a circulating water treatment device.

Background Art

[0002] A self-circulating hand washing device has been proposed (see Patent Document 1). In the hand washing device described in Patent Document 1, for example, the water after hand washing is passed through a primary purification filter, and the water after passing is held in a water storage tank.

Prior Art Documents

Patent Documents

[0003] (22)

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the water storage tank, for example, in order to prevent water from overflowing, it is necessary to manage the water level in the tank. In a circulating water treatment device, even the water that has passed through the primary purification filter contains impurities such as microorganisms. Therefore, in a tank that stores such circulating treated water, it is necessary to devise a way to accurately measure the water level in the tank. In addition, attention must also be paid to the biofilm formed in the tank that stores water containing impurities.

[0005] An object of the present disclosure is to accurately measure the water level in a water storage tank without being affected by biofilm formation even in water containing impurities.

Means for Solving the Problems

[0006] Note: There seems to be a formatting issue in the original text where the tag number (22) is not properly separated in the translation. Please check and correct if necessary. Also, in the original text, the tag number (19) is in parentheses which might be an error. I've translated it as normal but it should be verified.The water level sensor comprises a first electrode, a second electrode, and a control unit. The first electrode is installed at a first height in a tank that stores water containing impurities such as microorganisms and organic matter that can form biofilms. The second electrode is installed at a second height in the tank, which is higher than the first height. The control unit detects that the water has reached the second height when water comes into contact with the first and second electrodes. [Effects of the Invention]

[0007] According to this disclosure, the water level in a water storage tank can be accurately measured even if the water contains impurities, such as microorganisms that can form biofilms. [Brief explanation of the drawing]

[0008] [Figure 1] This is an external perspective view of the handwashing device 1 of this embodiment. [Figure 2] This is an external perspective view of the handwashing device 1 of this embodiment. [Figure 3] This is a block diagram showing the handwashing device 1, specifically the chemical unit 5, circulation unit 6, and control unit 60. [Figure 4] Figure 3 is a front view of the water storage tank 44. [Figure 5] Figure 4 is a front view of the water storage tank 44 shown in Figure 4, with the lid 441 removed from the tank section 442. [Figure 6] Figure 4 is a front view of the water storage tank 44 shown, in which the first electrode 4411, water level sensor 4412, supply tubes 4413 and 4414, discharge tube 4415, second electrode 4416, and third electrode 4417 are housed within the tank section 442. [Figure 7] This is a flowchart showing the water discharge process of handwashing device 1. [Figure 8] This is a flowchart showing the wastewater treatment process for handwashing device 1. [Figure 9] This is a flowchart showing the membrane filtration process of handwashing device 1. [Figure 10] This flowchart shows the water level measurement process for the water storage tank 44. [Figure 11] This flowchart shows the water level measurement process for the water storage tank 44. [Modes for carrying out the invention]

[0009] Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings. In the drawings used to illustrate the embodiment, the same reference numerals are generally used for identical components, and repeated descriptions thereof will be omitted.

[0010] <Overview> The hand-washing device 1 according to this embodiment has electrodes inside a water storage tank that holds water containing impurities such as microorganisms and organic matter that can form a biofilm, at a predetermined first height, and at a second height higher than the first height. When water comes into contact with the electrode near the bottom and the other electrodes, an electric current flows, and it is detected that the water has been stored up to the position where the other electrodes are installed. The water containing impurities such as microorganisms and organic matter that can form a biofilm may be called wastewater.

[0011] <Device configuration> The water storage tank 44 according to this embodiment will be described using a hand-washing device 1 that utilizes the water storage tank 44 as an example. Handwashing device 1 is, for example, a self-sustaining, circulating handwashing device.

[0012] Figures 1 and 2 are external perspective views of the handwashing device 1 of this embodiment. In the following description, the side on which the user of the handwashing device 1 stands will be referred to as the front of the handwashing device 1, and the opposite side will be referred to as the back of the handwashing device. As shown in Figure 1, the hand-washing device 1 comprises a housing 2 and an external module 7.

[0013] The housing 2 is equipped with a hand-washing basin (sink) 11, a faucet 12, and a dispenser 14. The housing 2 has a cylindrical shape. The housing 2 is formed by processing, for example, a drum can. A top plate 10 is provided at the upper part of the housing 2. An installation hole penetrating the top plate 10 is formed at the central part of the top plate 10.

[0014] A door 3 for accessing the circulation unit 6 provided inside the housing 2 is provided on the outer peripheral surface of the housing 2. The administrator of the handwashing device 1 can perform maintenance on the circulation unit 6 with the door 3 open. Not all components of the circulation unit 6 are provided inside the housing 2, and at least a part of it is arranged outside the housing 2 as a part of the external module 7.

[0015] As shown in FIG. 2, a handle 4 extending in the horizontal direction is provided on the back surface of the housing 2. A plurality of wheels 19 are provided on the lower surface of the housing 2. The user can move the housing 2 by moving the wheels 19 while gripping the handle 4.

[0016] A water outlet 13 for discharging washing water is formed at the tip of the faucet 12. Washing water is discharged from the water outlet 13 at a predetermined timing. An infrared sensor 23 (see FIG. 4) is provided on the faucet 12. When an object is detected by the infrared sensor 23, washing water is discharged from the water outlet 13 of the faucet 12. Note that the position of the infrared sensor 23 provided on the faucet 12 is not limited to the tip, and can be arbitrarily changed.

[0017] The dispenser 14 discharges a drug for maintaining skin hygiene from the nozzle 53 toward the inside of the handwashing sink 11. Drugs for maintaining skin hygiene include a cleaning agent for cleaning the skin (for example, a detergent such as soap water), and a liquid or hand lotion having a bactericidal action (for example, a disinfectant containing components such as alcohol).

[0018] The dispenser 14 is equipped with an infrared sensor 52 (see Figure 4). The infrared sensor 52 is positioned, for example, near the base of the nozzle 53 of the dispenser 14, so as to be able to detect hands approaching the handwashing tub 11. When an object is detected by the infrared sensor 52, the disinfectant is dispensed from the tip of the nozzle 53 of the dispenser 14.

[0019] <Configuration of drug unit 5 and circulation unit 6> Figure 3 is a block diagram showing the chemical unit 5, circulation unit 6, and control unit 60 of the handwashing device 1. As shown in Figure 3, the housing 2 contains a chemical unit 5 that supplies chemicals, a circulation unit 6 that purifies and circulates the washing water, and a control unit 60 that controls the circulation unit 6.

[0020] The control unit 60 is realized by the processor reading the program stored in storage, expanding it into memory, and executing the instructions contained in the expanded program. The processor is hardware for executing the instruction set written in the program, and is composed of an arithmetic unit, registers, peripheral circuits, etc. Storage is a memory device for saving data, such as non-volatile memory such as flash memory or an HDD (Hard Disk Drive). Memory is for temporarily storing programs and data processed by programs, etc., and is such as volatile memory such as DRAM (Dynamic Random Access Memory).

[0021] As shown in Figure 4, the circulation unit 6 includes at least a water discharge unit 20, a drainage unit 30, and a purification unit 40.

[0022] The water discharge unit 20 has the function of discharging water purified by the purification unit 40 in the circulation unit 6 from the spout 13 of the faucet 12.

[0023] The water discharge unit 20 mainly consists of a water discharge pump 21, a UV sterilization unit 22, and an infrared sensor 23.

[0024] The discharge pump 21 is located downstream of the water storage tank 46, which is provided in the purification unit 40. The discharge pump 21 is operated under the control of the control unit 60 and sends the water stored in the water storage tank 46 to the UV sterilization unit 22.

[0025] The UV sterilization unit 22 is located between the water discharge pump 21 and the faucet 12. The UV sterilization unit 22 sterilizes the water discharged from the water discharge pump 21 by irradiating it with ultraviolet light. The water that has passed through the UV sterilization unit 22 is discharged as washing water from the spout 13 of the faucet 12.

[0026] The drainage unit 30 has the function of draining the washing water that is discharged from the faucet 12 to the handwashing tub 11 in the circulation unit 6.

[0027] The drainage unit 30 mainly consists of a trap 35, a capacitance sensor 31, and a drainage pump 32. The trap 35 is installed in the piping that drains the washing water from the handwashing tub 11. The trap 35 prevents, for example, foul odors or gases from flowing back, and also prevents foreign matter that enters through the drain 17 from reaching the purification unit 40.

[0028] The drain pump 32 is located downstream of the trap 35. The drain pump 32 is operated under the control of the control unit 60 and sends the water that has passed through the trap 35 to the pre-treatment filter 41 provided in the purification unit 40. The pre-treatment filter 41 is an example of a primary purification filter according to this embodiment. Specifically, the control unit 60 operates the drain pump 32 in response to the detection of water by the capacitance sensor 31. For example, the control unit 60 operates the drain pump 32 while water is detected by the capacitance sensor 31. When water is no longer detected by the capacitance sensor 31, the control unit 60 stops the drain pump 32.

[0029] The capacitance sensor 31 is positioned between the trap 35 and the drain pump 32. The capacitance sensor 31 detects the capacitance in the drain pipe. This allows for the detection of water drained from the handwashing tub 11 and supplied through the trap 35. Note that the sensor used to detect the water supply is not limited to the capacitance sensor 31. The water supply may be detected by referring to other sensing results. For example, the capacitance sensor 31 may be a pressure sensor that detects pressure.

[0030] The purification unit 40 has the function of purifying the water supplied from the wastewater unit 30 in the circulation unit 6. The purification unit 40 mainly comprises a pre-treatment filter 41, a reverse osmosis membrane 42, a post-treatment filter 43, a water storage tank 44, a wastewater tank 45, a water storage tank 46, and a membrane filtration pump 47.

[0031] The pretreatment filter 41 is located downstream of the drainage pump 32. The pretreatment filter 41 pretreatments the water discharged from the drainage pump 32 to remove solids, water pollutants, low molecular weight compound surfactants, or carbonic acid components (detergent components), etc.

[0032] In this embodiment, an activated carbon filter is used as the pre-treatment filter 41, but it is not limited to this. For example, a wound filter, sediment filter, MF (microfiltration membrane), UF (ultrafiltration membrane), NF (nanofiltration membrane), ceramic filter, ion exchange filter, or metal membrane may be selected. In this embodiment, the pre-treatment filter 41 is located outside the housing 2 as part of the external module 7.

[0033] A pressure sensor 33 is positioned before the pre-treatment filter 41. The pressure sensor 33 detects the pressure of the water supplied to the pre-treatment filter 41.

[0034] A flow sensor 34 is positioned downstream of the pre-treatment filter 41. The flow sensor 34 detects the flow rate of the water that has been pre-treated by the pre-treatment filter 41.

[0035] The water storage tank 44 is located downstream of the pretreatment filter 41. The water storage tank 44 is a tank for storing the supplied water. The water that has been pretreated by the pretreatment filter 41 and the concentrated water that has been separated by the reverse osmosis membrane 42 and passed through the two-way solenoid valve 74 flow into the water storage tank 44. The water storage tank 44 stores water that flows in from two systems. A water level sensor is installed in the water storage tank 44. The water level sensor detects the water level stored in the water storage tank 44.

[0036] The membrane filtration pump 47 is positioned between the water storage tank 44 and the reverse osmosis membrane 42. The membrane filtration pump 47 is operated under the control of the control unit 60, and pressurizes the water stored in the water storage tank 44 to a preset pressure and supplies it to the reverse osmosis membrane 42. The preset pressure is, for example, a pressure that is at least higher than the osmotic pressure.

[0037] The reverse osmosis membrane 42 separates the water supplied, which has been pressurized to a high pressure by the membrane filtration pump 47, into permeate water from which dissolved components have been removed and concentrated water from which dissolved components have been concentrated. The reverse osmosis membrane 42 can be implemented, for example, by a spiral-type reverse osmosis membrane. The reverse osmosis membrane 42 is, for example, an example of a cross-flow type filtration membrane. A cross-flow type filtration membrane is a filtration membrane that performs filtration while suppressing the accumulation of suspended solids and colloids in the wastewater supplied to the membrane by creating a flow parallel to the membrane surface. In other words, a cross-flow type filtration membrane is a membrane that performs filtration by pumping wastewater at a pressure higher than the osmotic pressure of the membrane. Instead of a reverse osmosis membrane, a nanofiltration membrane (NF membrane), an ultrafiltration membrane (UF membrane), or a microfiltration membrane (MF membrane) may be used as such a cross-flow type filtration membrane.

[0038] If the two-way solenoid valve 74 is open, the concentrated water separated by the reverse osmosis membrane 42 is discharged to the water storage tank 44 via the two-way solenoid valve 74 and the pressure regulating valve 73. If the two-way solenoid valve 75 is open, the concentrated water separated by the reverse osmosis membrane 42 is discharged to the drainage tank 45 via the two-way solenoid valve 75. The permeate separated by the reverse osmosis membrane 42 is discharged to the post-treatment filter 43.

[0039] The two-way solenoid valve 74 is a device that opens and closes a valve using the electromagnetic force of an electromagnetic coil. The two-way solenoid valve 74 is normally open and closes in response to a signal from the control unit 60.

[0040] The pressure regulating valve 73 adjusts the flow rate or pressure of the concentrated water supplied to the water storage tank 44.

[0041] The two-way solenoid valve 75 is a device that opens and closes a valve using the electromagnetic force of an electromagnetic coil. The two-way solenoid valve 75 is normally closed and is structured to open in response to a signal from the control unit 60.

[0042] A sensor unit 61 is positioned upstream of the reverse osmosis membrane 42. In the illustrated example, the sensor unit 61 includes a pressure sensor, a flow sensor, and an EC / temperature sensor.

[0043] The pressure sensor detects the pressure of the water supplied to the reverse osmosis membrane 42.

[0044] The flow sensor detects the flow rate of water supplied to the reverse osmosis membrane 42.

[0045] The EC / temperature sensor detects the electrical conductivity and temperature of the water supplied to the reverse osmosis membrane 42. In addition to the sensors described above, the sensor unit 61 may also have sensors that sense at least one of the following: (1) pH, oxidation-reduction potential, alkalinity, ion concentration, hardness (2) Turbidity, color, viscosity, dissolved oxygen (3) Odors, ammonia nitrogen, nitrate nitrogen, nitrite nitrogen, total nitrogen, residual chlorine, total phosphorus, total organic carbon, total inorganic carbon, total trihalomethanes (4) Microbial sensor detection results, chemical oxygen demand, biological oxygen demand, (5) Cyanide, mercury, oil, surfactants (6) Detection results from optical sensors and TDS (Total Dissolved Solids) sensors (7) Mass spectrometry results, fine particles, zeta potential, surface potential

[0046] The post-treatment filter 43 is located downstream of the reverse osmosis membrane 42. The post-treatment filter 43 performs post-treatment on the permeate discharged from the reverse osmosis membrane 42 to remove impurities that could not be filtered out by the reverse osmosis membrane 42.

[0047] In this embodiment, an activated carbon filter is used as the post-processing filter 43, but it is not limited to this. For example, a wound filter, sediment filter, MF (microfiltration membrane), UF (ultrafiltration membrane), NF (nanofiltration membrane), ceramic filter, ion exchange filter, or metal membrane may be selected. In this embodiment, the post-processing filter 43 is located outside the housing 2 as part of the external module 7.

[0048] A sensor unit 62 is positioned before the post-processing filter 43. In the illustrated example, the sensor unit 62 includes a pressure sensor, a flow sensor, and an EC / temperature sensor.

[0049] The pressure sensor detects the pressure of the permeate supplied to the post-processing filter 43.

[0050] The flow sensor detects the flow rate of the permeate supplied to the post-processing filter 43.

[0051] The EC / temperature sensor detects the electrical conductivity and temperature of the permeate supplied to the post-processing filter 43. In addition to the sensors described above, the sensor unit 62 may also have sensors that sense at least one of (1) to (7) shown in the sensor unit 61.

[0052] The wastewater tank 45 is located downstream of the two-way solenoid valve 75. The wastewater tank 45 is a tank for storing the supplied wastewater. The wastewater tank 45 can be removed from the purification unit 40 and taken out through the door 3. Concentrated water that has been separated by the reverse osmosis membrane 42 and passed through the two-way solenoid valve 75 flows into the wastewater tank 45. The wastewater tank 45 stores the incoming concentrated water. A water level sensor is installed in the drainage tank 45. The water level sensor detects the water level of the wastewater stored in the drainage tank 45.

[0053] The water storage tank 46 is located downstream of the post-treatment filter 43. The water storage tank 46 is a tank for storing the supplied water. Water that has been post-treated by the post-treatment filter 43 flows into the water storage tank 46. Hypochlorous acid water is added to the water flowing into the water storage tank 46. The water storage tank 46 stores the incoming water to which hypochlorous acid water has been added. A water level sensor is installed in the water storage tank 46. The water level sensor detects the water level stored in the water storage tank 46.

[0054] The purification unit 40 includes a chlorine tank 67 and a chlorine pump 68. The chlorine tank 67 is a tank for storing hypochlorous acid water. Hypochlorous acid water is produced, for example, by dissolving hypochlorous acid tablets in water supplied to the chlorine tank 67. Alternatively, hypochlorous acid water may be produced by dissolving salt in water supplied to the chlorine tank 67 and then electrolyzing the resulting saline solution. Furthermore, an electrolysis unit that generates hypochlorous acid water by electrolyzing saline solution may be separately provided downstream of the chlorine tank 67.

[0055] A water level sensor is installed in the chlorine tank 67. The water level sensor detects the water level of the hypochlorous acid solution stored in the chlorine tank 67. The chlorine pump 68 is located downstream of the chlorine tank 67. The chlorine pump 68 is operated under the control of the control unit 60 and adds the hypochlorous acid water stored in the chlorine tank 67 to the water that has been post-treated by the post-treatment filter 43.

[0056] Inside the housing 2, a drug unit 5 is provided, consisting of a drug tank 50 and a dispenser 14. The dispenser 14 includes a drug pump 51, an infrared sensor 52, and a nozzle 53. Inside the nozzle 53, for example, an antenna for transmitting and receiving data is mounted.

[0057] The drug pump 51 is located downstream of the drug tank 50. The drug pump 51 is operated under the control of the control unit 60 and delivers the drug (e.g., soapy water) stored in the drug tank 50 to the nozzle 53 of the dispenser 14.

[0058] Specifically, the control unit 60 operates the drug pump 51 in response to the detection of an object by the infrared sensor 52 of the dispenser 14. For example, the control unit 60 operates the drug pump 51 for a certain period of time after an object is detected by the infrared sensor 52.

[0059] The chemical tank 50 is a tank for storing chemicals. A water level sensor is installed in the chemical tank 50. The water level sensor detects the level of the chemical stored in the chemical tank 50. When the chemical level falls below a predetermined value, the chemical is replenished.

[0060] <Configuration of water storage tank 44> Figure 4 is a front view of the water storage tank 44 shown in Figure 3. As shown in Figure 4, the water storage tank 44 has a lid 441 and a tank section 442.

[0061] Figure 5 is a front view of the water storage tank 44 shown in Figure 4, with the lid 441 removed from the tank section 442. As shown in Figure 5, the lid 441 is fitted with a first electrode 4411, a water level sensor 4412, supply tubes 4413 and 4414, a discharge tube 4415, a second electrode 4416, and a third electrode 4417. The first electrode 4411, the water level sensor 4412, the supply tubes 4413 and 4414, the discharge tube 4415, the second electrode 4416, and the third electrode 4417 are mounted so as to be suspended from the side of the lid 441 facing the tank section 442, toward the inside of the tank section 442. In other words, the first electrode 4411, the water level sensor 4412, the supply tubes 4413 and 4414, the discharge tube 4415, the second electrode 4416, and the third electrode 4417 are supported in a position that does not come into contact with water containing impurities and are located inside the tank section 442. In this embodiment, the impurities include, for example, microorganisms that can form biofilms and organic matter that serves as a nutrient source for microorganisms. In this embodiment, the microorganisms include, for example, bacteria, viruses, protists, algae, etc.

[0062] Figure 6 is a front view of the water storage tank 44 shown in Figure 4, in which the first electrode 4411, water level sensor 4412, supply tubes 4413 and 4414, discharge tube 4415, second electrode 4416, and third electrode 4417 are housed within the tank section 442.

[0063] The first electrode 4411 is positioned at a predetermined first height within the tank section 442. The predetermined first height is, for example, a height at which it comes into contact with water when a predetermined capacity (for example, about 1 liter) of water is stored in the tank section 442. The first electrode 4411 is positioned at the first height by being suspended from the lid section 441, for example, by a wire coated with a tube.

[0064] The first electrode 4411 is configured such that when the first electrode 4411 and the second electrode 4416 come into contact with water, an electric current flows through the water. The water level sensor according to this embodiment can be rephrased as having a first electrode 4411, a second electrode 4416, and a control unit 60. The first electrode 4411 is configured such that when the first electrode 4411 and the third electrode 4417 come into contact with water, an electric current flows through the water. The water level sensor according to this embodiment can be rephrased as having a first electrode 4411, a third electrode 4417, and a control unit 60. The first electrode 4411 is implemented, for example, by an electrical conductivity sensor, and an electric current flows when the first electrode 4411 comes into contact with water.

[0065] The water level sensor 4412 is a sensor that measures the water level in the water storage tank 44. The water level sensor 4412 is an example of a water level measuring instrument according to this embodiment. The water level sensor 4412 is a sensor that measures, for example, the change in liquid pressure due to the liquid level and converts it to a water level. The water level sensor 4412 can measure the water level linearly, for example. If the water level sensor 4412 is a pressure-measuring type sensor, the water level sensor 4412 is mounted substantially vertically from the lid portion 441 to near the bottom of the tank portion 442. The end of the water level sensor 4412 is positioned near the bottom of the tank portion 442.

[0066] The water level sensor 4412 is formed from a hard material such as metal and maintains a substantially vertical position from the lid 441 to near the bottom of the tank 442. If the water level sensor 4412 is formed from a material other than metal, such as a polymer compound such as polyethylene, a support member made of a hard material such as metal may be used to maintain a substantially vertical position from the lid 441 to near the bottom of the tank 442. In the example shown in Figure 5, the water level sensor 4412 is attached to the lid 441 so as to be located approximately in the center of the water storage tank 44.

[0067] The water level sensor 4412 is corrected based on the water level detected by the first electrode 4411, the second electrode 4416, and the third electrode 4417. The water level sensor according to this embodiment can be rephrased as including the water level sensor 4412.

[0068] Furthermore, since the water stored in the water storage tank 44 contains impurities, it is not recommended to use the floating sensor as the water level sensor 4412.

[0069] The supply tubes 4413 and 4414 are tubes that supply water to the water storage tank 44. The supply tubes 4413 and 4414 are made of a polymer compound such as polyethylene. The supply tube 4413 supplies water that has been pretreated by the pretreatment filter 41 to the water storage tank 44. The supply tube 4414 supplies concentrated water that has been separated by the reverse osmosis membrane 42 and passed through the two-way solenoid valve 74 to the water storage tank 44.

[0070] The ends of the supply tubes 4413 and 4414 are positioned near the bottom of the tank section 442. The ends of the supply tubes 4413 and 4414 are positioned away from the end of the water level sensor 4412 so that the water supplied by the supply tubes 4413 and 4414 does not affect the water level measurement by the water level sensor 4412. For example, the ends of the supply tubes 4413 and 4414 are positioned away from the end of the water level sensor 4412 so that as few bubbles as possible enter the tip of the water level sensor 4412.

[0071] The discharge tube 4415 is a tube that discharges water from the water storage tank 44. The discharge tube 4415 is made of a polymer compound such as polyethylene. The discharge tube 4415 discharges the water stored in the water storage tank 44 to the outside of the water storage tank 44 by the pressure generated by, for example, the membrane filtration pump 47.

[0072] The end of the discharge tube 4415 is positioned near the bottom of the tank section 442. The end of the discharge tube 4415 is positioned away from the end of the water level sensor 4412 so that the water drawn in by the discharge tube 4415 does not affect the water level measurement by the water level sensor 4412. For example, the end of the discharge tube 4415 is positioned away from the end of the water level sensor 4412 so that as few bubbles as possible enter the tip of the water level sensor 4412.

[0073] The first electrode 4411, supply tubes 4413 and 4414, and discharge tube 4415 are attached to the lid 441 and have a certain length that extends to near the bottom of the tank 442. Therefore, without a predetermined restraint, they will spread out individually, making it difficult to stably adjust the water level of the water storage tank 44. Specifically, for example, if the position of the first electrode 4411 fluctuates, it becomes impossible to detect the accurate water level. Also, if the positions of the supply tubes 4413 and 4414 fluctuate, their ends will move when discharging water, creating unwanted water flow within the water storage tank 44. Furthermore, if the position of the discharge tube 4415 fluctuates, it will affect the operation of discharging water from the water storage tank 44.

[0074] Therefore, by bundling the first electrode 4411, the water level sensor 4412, the supply tubes 4413 and 4414, and the discharge tube 4415 with a clip 4418, the first electrode 4411, the supply tubes 4413 and 4414, and the discharge tube 4415 are stably positioned near the bottom of the tank section 442. Since the water level sensor 4412 is positioned almost vertically, fixing the first electrode 4411, the supply tubes 4413 and 4414, and the discharge tube 4415 to the water level sensor 4412 (or the support member for the water level sensor 4412) makes it possible to prevent the first electrode 4411, the supply tubes 4413 and 4414, and the discharge tube 4415 from coming apart. When the first electrode 4411, supply tubes 4413, 4414, and discharge tube 4415 are fixed to the water level sensor 4412, the water level sensor 4412 may also be referred to as a support member for the first electrode 4411, supply tubes 4413, 4414, and discharge tube 4415.

[0075] The second electrode 4416 is positioned at a predetermined second height within the tank section 442. The predetermined second height is, for example, a height at which the electrode comes into contact with water when a predetermined capacity (for example, about 2.5 liters) of water is stored in the tank section 442. The second height is higher than the first height. The second electrode 4416 is positioned at the second height by being suspended from the lid section 441 by a wire, for example, coated with a tube, which is routed from the lid section 441.

[0076] The second electrode 4416 is positioned to avoid contact with other components, such as the first electrode 4411, the water level sensor 4412, the supply tubes 4413 and 4414, and the discharge tube 4415. Specifically, the second electrode 4416 is not bundled with the first electrode 4411, the water level sensor 4412, the supply tubes 4413 and 4414, and the discharge tube 4415. In other words, the second electrode 4416 is positioned at a predetermined distance in the outer circumferential direction of the water storage tank 44 from the bundle of the first electrode 4411, the water level sensor 4412, the supply tubes 4413 and 4414, and the discharge tube 4415. In other words, the second electrode 4416 is positioned at a predetermined distance from the first electrode 4411. The predetermined distance represents, for example, a distance such that a biofilm does not form on the second electrode 4416.

[0077] The length from the lid 441 to the second electrode 4416 is shorter than the length from the lid 441 to the first electrode 4411. Furthermore, since the second electrode 4416 is far from the ends of the supply tubes 4413 and 4414, and the end of the discharge tube 4415, it is less affected by the water flow generated by water supply or discharge. Therefore, fluctuations in the second electrode 4416 are smaller than fluctuations in the first electrode 4411, and thus have little effect on water level detection.

[0078] By positioning the second electrode 4416 so as to avoid contact with other components, such as the first electrode 4411, the water level sensor 4412, the supply tubes 4413 and 4414, and the discharge tube 4415, it is possible to suppress the adhesion of impurities in the water to the second electrode 4416. This prevents deterioration of the water level detection function.

[0079] The third electrode 4417 is positioned at a predetermined third height within the tank section 442. This predetermined third height is, for example, a height at which contact occurs when the tank section 442 is filled with water just before it is full. Specifically, the third height is near the point in the upper part of the tank section 442 where the diameter begins to contract toward the opening. The third height is higher than the second height. The third electrode 4417 is positioned at the third height in such a manner that a wire coated with a tube is drawn from the lid section 441 and the electrode is suspended from the lid section 441.

[0080] The third electrode 4417 is positioned to avoid contact with other components, such as the first electrode 4411, the water level sensor 4412, the supply tubes 4413 and 4414, and the discharge tube 4415. Specifically, the third electrode 4417 is not bundled with the first electrode 4411, the water level sensor 4412, the supply tubes 4413 and 4414, and the discharge tube 4415. In other words, the third electrode 4417 is positioned at a predetermined distance in the outer circumference direction of the water storage tank 44 from the bundle of the first electrode 4411, the water level sensor 4412, the supply tubes 4413 and 4414, and the discharge tube 4415. In other words, the third electrode 4417 is positioned at a predetermined distance from the first electrode 4411. The predetermined distance represents, for example, a distance such that a biofilm does not form on the third electrode 4417.

[0081] Furthermore, a control board having the function of controlling the first electrode 4411, the water level sensor 4412, the second electrode 4416, and the third electrode 4417 may be separated from the control unit 60 and attached to the cover portion 441.

[0082] <Control process for handwashing device 1> Next, the control process of the handwashing device 1 will be explained. Figures 7 to 9 are explanatory diagrams showing the control process of the handwashing device 1.

[0083] (Water discharge process of water discharge unit 20) First, we will explain the water discharge process from the faucet 12 in the water discharge unit 20. As shown in Figure 7, the control unit 60 turns off the water discharge pump 21 (step S11).

[0084] The control unit 60 determines whether a predetermined timing has been reached (step S12). Specifically, the control unit 60 determines whether a preset time has been reached, whether a preset cycle has elapsed, or whether a preset time has elapsed since the last time the water discharge pump 21 was driven. If the predetermined timing has been reached (Yes in step S12), the control unit 60 operates the water discharge pump 21 (step S13). As a result, water circulates in the handwashing device 1 at times other than when the user is washing their hands.

[0085] The water discharge pump 21 sends water stored in the water storage tank 46 and passes it through the UV sterilization unit 22. The UV sterilization unit 22 sterilizes the water discharged from the water discharge pump 21 by irradiating it with ultraviolet light. The water that has passed through the UV sterilization unit 22 is discharged as washing water from the spout 13 of the faucet 12.

[0086] The control unit 60 determines whether or not an object has been detected by the infrared sensor 23 (step S14). When a user uses the handwashing device 1, they place their hands into the handwashing basin 11 and allow the infrared sensor 23, located at the tip of the faucet 12, to detect their hands.

[0087] The control unit 60 stops the water discharge pump 21 in response to the detection of hands by the infrared sensor 23 (YES in step S14) (step S15). When the user washes their hands, the water discharge pump 21 is temporarily stopped to allow for differentiation between forced water discharge and water discharge due to hand washing. After stopping the water discharge pump 21, the control unit 60 restarts the water discharge pump 21 in response to operation due to hand washing (step S16).

[0088] The control unit 60 determines whether or not an object has been detected by the infrared sensor 23 (step S17). When the user finishes washing their hands or dispenses the disinfectant from the dispenser 14, they move their hands away from the infrared sensor 23 located at the tip of the faucet 12. The control unit 60 stops the water discharge pump 21 (step S11) in response to the non-detection of hands by the infrared sensor 23 (NO in step S17).

[0089] In step S17, if the infrared sensor 23 does not detect the fingers (YES in step S17), the control unit 60 continues to operate the water discharge pump 21 (step S16).

[0090] In step S12, if the predetermined timing has not occurred (No. in step S12), the control unit 60 determines whether or not an object has been detected by the infrared sensor 23 (step S18). When a user uses the handwashing device 1, they place their hands into the handwashing basin 11 and allow the infrared sensor 23 located at the tip of the faucet 12 to detect their fingers.

[0091] The control unit 60 activates the water discharge pump 21 (step S19) in response to the detection of fingers by the infrared sensor 23 (YES in step S18). On the other hand, if the infrared sensor 23 does not detect fingers in step S18 (NO in step S18), the control unit 60 does not operate the water discharge pump 21 (step S11).

[0092] The control unit 60 determines whether or not an object has been detected by the infrared sensor 23 (step S110). When the user finishes washing their hands or dispenses the disinfectant from the dispenser 14, they move their hands away from the infrared sensor 23 located at the tip of the faucet 12. The control unit 60 stops the water discharge pump 21 (step S11) in response to the non-detection of hands by the infrared sensor 23 (NO in step S110).

[0093] In step S110, if the infrared sensor 23 does not detect the fingers (YES in step S110), the control unit 60 continues to operate the water discharge pump 21 (step S19).

[0094] In step S14, if the infrared sensor 23 does not detect a hand (NO in step S14), the control unit 60 determines whether a predetermined time has elapsed since the water discharge pump 21 was started (step S111). If the predetermined time has elapsed (Yes in step S111), the control unit 60 stops the water discharge pump 21 (step S11). If the predetermined time has not elapsed (No in step S111), the control unit 60 continues to operate the water discharge pump 21 (step S13). The water discharge unit 20 repeats these processes and discharges cleaning water from the faucet 12. The control unit 60 may also measure the time that the infrared sensor 23 detects fingers, and if fingers are detected for a certain period of time, it may stop the water discharge. In the example shown in Figure 7, the case where step S14 determines whether or not the infrared sensor 23 has detected the user's hands is explained. However, the determination made in step S14 is not limited to detection by the infrared sensor 23. For example, the control unit 60 may determine whether or not the user is likely to wash their hands using the handwashing device 1. For example, the control unit 60 may determine whether or not the user is likely to wash their hands using the handwashing device 1 by determining whether or not the user is approaching the handwashing device 1 using a monitoring device. Alternatively, the control unit 60 may determine whether or not the user is likely to wash their hands using the handwashing device 1 by determining whether or not an item has been placed in the UV sterilization device 80.

[0095] (Wastewater treatment of drainage unit 30) Next, we will describe the wastewater treatment in the wastewater unit 30. As shown in Figure 8, when there is no drainage from the handwashing tub 11, the drainage pump 32 is stopped (step S21). Then, when the washing water discharged from the faucet 12 toward the handwashing tub 11 is drained from the drain port 17 of the handwashing tub 11, the capacitance sensor 31 detects the drainage (step S22).

[0096] When the capacitive sensor 31 detects drainage (YES in step S22), the control unit 60 activates the drainage pump 32 (step S23). On the other hand, if the capacitance sensor 31 does not detect drainage (NO in step S22), the control unit 60 does not operate the drainage pump 32 (step S21).

[0097] In step S23, the drain pump 32 sends the drained water to the pre-treatment filter 41. The water that has been pre-treated by the pre-treatment filter 41 flows into the storage tank 44 and is stored in the storage tank 44. The pressure sensor 33 detects the pressure of the water sent to the pre-treatment filter 41. The flow rate sensor 34 detects the flow rate of the water that has been pre-treated by the pre-treatment filter 41.

[0098] Then, after step S23, when the capacitance sensor 31 detects that there is no more wastewater flowing in from the drain port 17 (NO in step S24), the control unit 60 stops the drain pump 32 (step S21).

[0099] On the other hand, in step S24, if the capacitance sensor 31 detects that wastewater is continuing to flow in from the drain port 17 (YES in step S24), the control unit 60 continues to operate the drain pump 32 (step S23).

[0100] The drainage unit 30 repeats these processes and supplies the water discharged from the drain outlet 17 of the handwashing tub 11 to the pretreatment filter 41.

[0101] (Control processing of the purification unit 40) Next, the cleaning process in the purification unit 40 will be described. As shown in Figure 9, initially the membrane filtration pump 47 is stopped (step S31).

[0102] The control unit 60 determines whether or not the drain pump 32 is operating (step S32). If the drainage pump 32 is operating (YES in step S32), the control unit 60 operates the membrane filtration pump 47 (step S33). As a result, the water stored in the water storage tank 44 is supplied to the reverse osmosis membrane 42 at high pressure by the membrane filtration pump 47.

[0103] On the other hand, if the drainage pump 32 is not operating (NO in step S32), the control unit 60 will keep the membrane filtration pump 47 inactive (step S31).

[0104] In step S33, the water supplied to the reverse osmosis membrane 42 is separated into concentrated water and permeate in the reverse osmosis membrane 42. The permeate is supplied to the post-treatment filter 43. The concentrated water flows into the storage tank 44 via the two-way solenoid valve 74. However, since the two-way solenoid valve 75 is closed, the concentrated water does not flow into the drainage tank 45.

[0105] The permeate is then subjected to post-treatment in the post-treatment filter 43. After post-treatment in the post-treatment filter 43, hypochlorous acid water is added to the permeate and it flows into the storage tank 46.

[0106] After step S33, the control unit 60 determines whether the electrical conductivity detected by the EC / temperature sensor of the sensor unit 61 located upstream of the reverse osmosis membrane 42 is less than a predetermined value (step S34). If the electrical conductivity detected by the EC / temperature sensor is below a predetermined value (YES in S34), the control unit 60 determines whether the drain pump 32 is operating (step S35). If the drain pump 32 is operating (YES in step S35), the control unit 60 continues to operate the membrane filtration pump 47 (step S33).

[0107] On the other hand, in step S34, if the electrical conductivity detected by the EC / temperature sensor exceeds a predetermined value (NO in step S34), the control unit 60 turns on the two-way solenoid valve 74 and the two-way solenoid valve 75 (step S36). As a result, the two-way solenoid valve 74 is closed and the two-way solenoid valve 75 is opened.

[0108] When the two-way solenoid valve 74 is closed and the two-way solenoid valve 75 is opened, the concentrated water separated by the reverse osmosis membrane 42 flows into the drainage tank 45 via the two-way solenoid valve 75. In other words, the control unit 60 determines the amount of impurities in the concentrated water based on the change in electrical conductivity detected by the EC / temperature sensor. Concentrated water that is determined to contain a large amount of impurities is discharged into the drainage tank 45.

[0109] When the water level of the concentrated water stored in the drainage tank 45 reaches a predetermined value, an alert is issued, for example, to the administrator of the handwashing device 1. Upon receiving the alert, the administrator discards the water stored in the drainage tank 45.

[0110] The control unit 60 continues the process in step S36 for a predetermined time (step S37), and after the predetermined time has elapsed, turns off the two-way solenoid valves 74 and 75. As a result, the two-way solenoid valve 74 opens and the two-way solenoid valve 75 closes. In this way, when the two-way solenoid valve 74 is opened and the two-way solenoid valve 75 is closed, the concentrated water separated by the reverse osmosis membrane 42 flows into the water storage tank 44 via the two-way solenoid valve 74. Then, the control unit 60 stops the membrane filtration pump 47 (step S31).

[0111] In step S35, if the drainage pump 32 is stopped (NO in step S35), the control unit 60 stops the membrane filtration pump 47 after a predetermined time has elapsed (step S38) (step S31).

[0112] The purification unit 40 repeats these processes to purify the water discharged by the drainage unit 30 and stores it in the water storage tank 46.

[0113] (Water level measurement process for water storage tank 44) Next, the water level measurement process in the water storage tank 44 will be explained. Figures 10 and 11 are explanatory diagrams showing the water level measurement process in the water storage tank 44.

[0114] As shown in Figure 10, the control unit 60 determines whether or not current has been detected at the second electrode 4416 (step S51). When water is stored in the water storage tank 44 and the water reaches the second height, the second electrode 4416 comes into contact with the water, and current flows through the second electrode 4416.

[0115] If a current is detected at the second electrode 4416 (Yes in step S51), the control unit 60 generates a signal indicating that water has been stored in the water storage tank 44 up to the second height (step S52). If no current is detected at the second electrode 4416 (No in step S51), the control unit 60 repeats the process in step S51 until a current is detected at the second electrode 4416.

[0116] The control unit 60 determines whether the difference between the water level obtained by the water level sensor 4412 and the second height is less than a predetermined value (step S53). Specifically, when a current is detected at the second electrode 4416, the control unit 60 obtains the water level measured by the water level sensor 4412. The control unit 60 compares the obtained water level with the second height and determines whether the difference is less than a predetermined value. If the difference between the obtained water level and the second height is less than a predetermined value (Yes in step S53), the control unit 60 proceeds to step S51. If the difference between the obtained water level and the second height is greater than or equal to a predetermined value (No in step S53), the control unit 60 corrects the water level sensor 4412 so that the obtained water level becomes the second height (step S54).

[0117] As shown in Figure 11, the control unit 60 determines whether or not current is detected at the third electrode 4417 (step S61). When water is stored in the water storage tank 44 and the water reaches the third height, the third electrode 4417 comes into contact with the water, and current flows through the third electrode 4417.

[0118] If a current is detected at the third electrode 4417 (Yes in step S61), the control unit 60 generates a signal indicating that water has been stored in the water storage tank 44 up to the third height (step S62). If no current is detected at the third electrode 4417 (No in step S61), the control unit 60 repeats the process in step S61 until a current is detected at the third electrode 4417.

[0119] The control unit 60 determines whether the difference between the water level obtained by the water level sensor 4412 and the third height is less than a predetermined value (step S63). Specifically, when a current is detected at the third electrode 4417, the control unit 60 obtains the water level measured by the water level sensor 4412. The control unit 60 compares the obtained water level with the third height and determines whether the difference is less than a predetermined value. If the difference between the obtained water level and the third height is less than a predetermined value (Yes in step S63), the control unit 60 proceeds to step S61. If the difference between the obtained water level and the third height is greater than or equal to a predetermined value (No in step S63), the control unit 60 corrects the water level sensor 4412 so that the obtained water level becomes the third height (step S64).

[0120] As described above, in the above embodiment, the first electrode 4411 is installed at a first height in the tank 44 that stores water containing impurities including microorganisms that can form a biofilm. The second electrode 4416 is installed at a second height in the tank 44 that is higher than the first height. The control unit 60 detects that the water has reached the second height when it comes into contact with the first electrode 4411 and the second electrode 4416. This makes it possible to accurately detect that the water containing impurities has reached a predetermined position in the tank 44.

[0121] Therefore, the water level sensor according to this embodiment can accurately measure the water level of water containing impurities, including microorganisms that can form biofilms.

[0122] Furthermore, in the above embodiment, the third electrode 4417 is installed at a third height higher than the second height inside the tank 44. The control unit 60 detects that the water has reached the third height when water comes into contact with the first electrode 4411 and the third electrode 4417. This makes it possible to accurately detect the arrival of multiple water levels, even when there are multiple water levels to be tracked.

[0123] Furthermore, in the above embodiment, the first electrode 4411 is fixed so as to be maintained in a predetermined position in the tank 44 at a first height. The second electrode 4416 is positioned so as not to come into contact with the component including the first electrode 4411. As a result, water flows without stagnating around the second electrode 4416, making it possible to suppress the adhesion of dirt to the second electrode 4416. This makes it possible to suppress a decrease in the accuracy of water level detection.

[0124] Furthermore, in the above embodiment, the first electrode 4411 is mounted so as to be suspended from the wall surface above the water level in the tank 44 and fixed to a support member. The second electrode 4416 is mounted so as to be suspended from the wall surface above the water level in the tank 44 and is not fixed to a support member. As a result, the second electrode 4416 is separated from the group of members fixed to the support member, and dirt does not adhere to it. In other words, biofilm does not form on the second electrode 4416. Therefore, it is possible to suppress a decrease in the accuracy of water level detection.

[0125] Furthermore, in the above embodiment, the second electrode 4416 is positioned at a predetermined distance from the first electrode 4411. As a result, the second electrode 4416 is separated from the first electrode 4411, which has multiple components, and dirt does not adhere to it. In other words, biofilm does not form on the second electrode 4416. Therefore, it is possible to suppress a decrease in the accuracy of water level detection.

[0126] Furthermore, in the above embodiment, the water level measuring instrument 4412 measures the water level in the tank 44. The control unit 60 corrects the water level measuring instrument 4412 based on the water level recognized when water comes into contact with the first electrode 4411 and the second electrode 4416. As a result, the water level sensor according to this embodiment can measure the water level in the tank 44 linearly and with high accuracy.

[0127] Furthermore, in the above embodiment, the water level measuring instrument 4412 measures the water level in the tank 44. The control unit 60 corrects the water level measuring instrument 4412 based on the water level recognized when water comes into contact with the first electrode 4411 and the third electrode 4417. As a result, the water level sensor according to this embodiment can measure the water level in the tank 44 linearly and with high accuracy.

[0128] <Variation> In the above embodiment, an example was described in which a second electrode 4416 and a third electrode 4417 are installed in the water storage tank 44. However, electrodes other than the first electrode 4411 installed in the water storage tank 44 are not limited to these. If it is necessary to detect the water level more precisely, three or more electrodes may be installed.

[0129] Furthermore, in the above embodiment, the first electrode 4411, the water level sensor 4412, the supply tubes 4413 and 4414, the discharge tube 4415, the second electrode 4416, and the third electrode 4417 were described as being mounted so as to be suspended from the surface of the lid portion 441 facing the tank portion 442 toward the inside of the tank portion 442. However, the mounting of the first electrode 4411, the water level sensor 4412, the supply tubes 4413 and 4414, the discharge tube 4415, the second electrode 4416, and the third electrode 4417 is not limited to the lid portion 441. Depending on the shape of the tank, the part located above the water surface may not be the lid portion. The first electrode 4411, the water level sensor 4412, the supply tubes 4413 and 4414, the discharge tube 4415, the second electrode 4416, and the third electrode 4417 may be attached to any wall surface above the water level inside the tank, other than the lid.

[0130] Furthermore, the above embodiment described a case in which a conductor covered with a tube is connected to the electrode. However, the conductor is not limited to being covered with a tube. The conductor connected to the electrode may be covered with a hard material such as metal. This eliminates the need to bundle the first electrode 4411 to the indicator member. The second electrode 4416 is positioned to avoid contact with other components, such as the first electrode 4411, the water level sensor 4412, the supply tubes 4413 and 4414, and the discharge tube 4415.

[0131] Furthermore, although the above embodiment described the supply tube and discharge tube within the water storage tank 44, the supply tube and discharge tube within the water storage tank 44 are not limited to those described above. For example, the supply tube is not limited to two, and the discharge tube is not limited to one.

[0132] Furthermore, the above embodiment described a case in which the hand-washing device 1 is equipped with a water storage tank 44. However, the device equipped with a water storage tank 44 is not limited to the hand-washing device 1. In addition to indoor or outdoor shower booths, a circulating water treatment device that purifies and reuses kitchen or laundry wastewater, rainwater, groundwater, surface water, etc., may also be equipped with a water storage tank.

[0133] Furthermore, in the above embodiment, a water storage tank 44 that stores water that has passed through a primary purification filter was described as an example. However, the tank according to this embodiment is not limited to storing water that has passed through a primary purification filter. The tank according to this embodiment is a tank that stores water containing impurities, including microorganisms that can form biofilms, and does not necessarily have to be preceded by a primary purification filter. For example, the tank according to this embodiment may be used in a circulating water treatment system in which water is circulated and reused. Also, the tank according to this embodiment may be used in a predetermined module that constitutes a circulating water treatment system.

[0134] While preferred embodiments of the present disclosure have been described above, the disclosure is not limited to these specific embodiments, and includes the inventions described in the claims and their equivalents. Furthermore, the configurations of the apparatus described in the above embodiments and modifications can be partially omitted or combined, as long as no technical inconsistency arises.

[0135] The details described in each of the above embodiments are noted below.

[0136] (Note 1) A water level sensor comprising: a first electrode installed at a first height in a tank for storing water containing impurities including microorganisms that can form a biofilm; a second electrode installed at a second height higher than the first height in the tank; and a control unit that detects when water comes into contact with the first and second electrodes and the water reaches the second height. (Note 2) A water level sensor as described in Appendix 1, comprising a third electrode installed in the tank at a third height higher than the second height, wherein the control unit detects that the water has reached the third height when water comes into contact with the first electrode and the third electrode. (Note 3) The water level sensor as described in (Note 1) or (Note 2), wherein the first electrode is fixed so as to be maintained in a predetermined position in the tank at a first height, and the second electrode is positioned so as not to be in contact with the member including the first electrode. (Note 4) The water level sensor described in Appendix 3, wherein the first electrode is mounted so as to be suspended from the wall above the water level in the tank and fixed to a support member, and the second electrode is mounted so as to be suspended from the wall above the water level in the tank and is not fixed to a support member. (Note 5) The water level sensor described in (Appendix 4), wherein the second electrode is positioned so as to be separated from the first electrode by a predetermined distance. (Note 6) It is equipped with a water level measuring device for measuring the water level in the tank. The control unit corrects the water level measuring instrument based on the water level recognized when water comes into contact with the first electrode and the second electrode, as described in any of the notes (1) to (5). (Note 7) It is equipped with a water level measuring device for measuring the water level in the tank. The control unit corrects the water level measuring instrument based on the water level recognized when water comes into contact with the first electrode and the third electrode, as described in any of the notes (1) to (5). (Note 8) A water storage tank for storing water containing impurities including microorganisms that can form a biofilm, the water storage tank being equipped with a water level sensor as described in any of (Appendix 1) to (Appendix 7). (Note 9) A handwashing device comprising a sink from which washing water is discharged, a primary purification filter for purifying the wastewater from the sink, and a tank for storing water containing impurities that has passed through the primary purification filter, wherein the tank is equipped with a water level sensor as described in any of (Appendix 1) to (Appendix 7). (Note 10) A circulating water treatment apparatus comprising a tank for storing water containing impurities including microorganisms capable of forming a biofilm, wherein the tank is equipped with a water level sensor as described in any of (Appendix 1) to (Appendix 7). [Explanation of symbols]

[0137] 1…Handwashing device 10... Tabletop 11…Handwashing basin 12... Faucet 13... Spout 14…Dispenser 19...Wheel 2…Cabinet 3... Door 4…Handle 8…Mounting part 9…Mounting part 20...Water discharge unit 21...Water discharge pump 22...UV sterilization section 23…Infrared sensor 30…Drainage unit 31…Capacitive sensor 32... Drainage pump 33... Pressure sensor 34…Flow sensor 35... Trap 40…Purification unit 41…Processing filter 42...Permeable membrane 43…Post-processing filter 44...Water storage tank 45... Drainage tank 46...Water storage tank 47…Membrane filtration pump 5…Pharmacy Unit 50... Chemical tank 51…Medication pump 52…Infrared sensor 53… Nozzle 6…Circulation unit 60... Control Unit 61...Sensor section 62...Sensor section 67... Chlorine tank 68... Chlorine pump 7…External module 73... Pressure regulating valve 74...Two-way solenoid valve 75...Two-way solenoid valve 80…UV sterilizer 81... Insertion opening

Claims

1. A water storage tank for storing treated water, comprising: A first tube for supplying treated water to the water storage tank; a second tube for discharging the treated water stored in the water storage tank; Equipped with A water tank in which an end of the first tube and an end of the second tube are arranged to face in directions away from each other.

2. A sensor is provided inside the water storage tank, 2. The water tank according to claim 1, wherein the end of the first tube is disposed so as to face away from the end of the second tube and the sensor.

3. A water tank as described in claim 1, wherein the first tube and the second tube are attached so as to be suspended from a wall surface above the water level in the water tank.

4. A water tank as described in claim 2, wherein the first tube, the second tube, and the sensor are mounted so as to be suspended from a wall surface above the water surface in the water tank.

5. A circulating water treatment device having a water storage tank described in any one of claims 1 to 4.

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