Electrolytic water generator and control method thereof

Abstract

To provide an electrolytic water generator capable of suppressing a decrease in a dissolved hydrogen concentration of electrolytic water in a standby state.SOLUTION: An electrolytic water generator 1 includes a water supply valve 2, an electrolytic unit 3, a tank 5, a water level detection section 6, and a control section 8 for controlling the water supply valve 2 and the electrolytic unit 3. The control section 8 includes, as control modes, a water generation mode in which the water supply valve 2 is opened and electrolytic water generated by the electrolytic unit 3 is supplied to the tank 5, and a standby mode in which the water supply valve 2 is closed and the electrolytic unit 3 stands by without performing electrolysis. The water generation mode and the standby mode are alternately repeated. The control section 8 includes a calculation section that calculates the rate of decrease of the water level in the tank 5 based on the output from the water level detection section 6, a determination section that determines when to shift from the water generation mode to the standby mode, and a transition section that shifts the control mode from the water generation mode to the standby mode.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an electrolyzed water generator.

Background Art

[0002] In recent years, dialysis treatment using electrolyzed water generated by an electrolyzed water generator has attracted attention. For example, it is known that electrolyzed hydrogen water in which hydrogen gas generated by electrolyzing water is dissolved contributes to reducing the oxidative stress of patients (see, for example, Patent Document 1 below).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In large-scale hospitals and the like, dialysis treatment is performed on a large number of patients simultaneously. For this reason, the electrolyzed water generator is provided with a tank for storing a large amount of electrolyzed water.

[0005] On the other hand, dialysis treatment is not usually performed constantly, and there are also time periods when the electrolyzed water in the tank is not consumed. In such time periods, in order to suppress an excessive increase in the dissolved hydrogen concentration of the electrolyzed water, the circulation of the electrolyzed water between the tank and the electrolysis unit and the electrolysis in the electrolysis unit are stopped, and the electrolyzed water in the tank is retained in the tank and waits without electrolysis being performed.

[0006] However, the dissolved hydrogen concentration gradually decreases due to the escape of the hydrogen gas dissolved from the electrolyzed water in the standby state.

[0007] The present invention has been devised in view of the above actual situation, and the main object thereof is to provide an electrolyzed water generator capable of suppressing a decrease in the dissolved hydrogen concentration of electrolyzed water in a standby state.

Means for Solving the Problems

[0008] The present invention is an electrolyzed water generator, a water supply valve for controlling the supply of raw water, an electrolysis unit for generating electrolyzed water by electrolyzing the raw water supplied from the water supply valve, a tank for storing the electrolyzed water generated by the electrolysis unit, a water level detection unit for detecting the water level in the tank, and a control unit for controlling the water supply valve and the electrolysis unit, wherein the control unit has, as control modes, a water production mode in which the water supply valve is opened and the electrolyzed water generated by the electrolysis unit is supplied to the tank, and a standby mode in which the water supply valve is closed and electrolysis is not performed by the electrolysis unit and the unit waits, the water production mode and the standby mode are alternately and repeatedly executed, the control unit includes a calculation unit for calculating a decrease rate of the water level in the tank based on an output from the water level detection unit, a determination unit for determining a first timing to shift from the water production mode to the standby mode according to the decrease rate, and a shift unit for shifting the control mode from the water production mode to the standby mode based on the first timing.

Advantages of the Invention

[0009] In the electrolyzed water generator of the present invention, according to the decrease rate of the water level in the tank, the control unit determines the timing to shift from the water production mode to the standby mode and shifts the control mode. Thereby, the water level in the tank is optimized, and it becomes possible to suppress a decrease in the dissolved hydrogen concentration of electrolyzed water in a standby state.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

BEST MODE FOR CARRYING OUT THE INVENTION

[0011] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows a schematic configuration of the electrolyzed water generator 1 of the present embodiment. The electrolyzed water generator 1 is a device for generating electrolyzed water and is connected to a dialysate preparation device 100 for preparing a dialysate. The electrolyzed water generator 1 supplies the generated electrolyzed water to the dialysate preparation device 100.

[0012] The electrolyzed water generation device 1 includes a water supply valve 2 for controlling the supply of raw water, an electrolysis unit 3 for generating electrolyzed water, a tank 5 for storing the electrolyzed water, a water level detection unit 6 for detecting the water level in the tank 5, and a control unit 8 for controlling the water supply valve 2, the electrolysis unit 3, etc.

[0013] Tap water is generally used as the raw water supplied to the water supply valve 2, but other types of water such as well water and groundwater can also be used. The raw water is subjected to pretreatment such as softening and then supplied to the water supply valve 2. Then, the raw water to be electrolyzed is supplied to the electrolysis unit 3 via the water supply valve 2.

[0014] Figure 2 shows the electrolysis unit 3. The electrolysis unit 3 includes an electrolytic cell 4. When the dialysis fluid prepared by the dialysis fluid preparation device 100 is used for dialysis of a large number of patients, as shown in Figure 2, it is desirable that the electrolysis unit 3 is configured to include a plurality of electrolytic cells 4. The plurality of electrolytic cells 4 are connected to each other in parallel as flow paths. By operating such a plurality of electrolytic cells 4 simultaneously, a large amount of electrolyzed water can be generated quickly.

[0015] The electrolytic cell 4 includes an electrolysis chamber 40, an anode feeder 41, a cathode feeder 42, and a diaphragm 43. The electrolysis chamber 40 is divided by the diaphragm 43 into an anode chamber 40a in which the anode feeder 41 is disposed and a cathode chamber 40b in which the cathode feeder 42 is disposed. The raw water is supplied to the anode chamber 40a and the cathode chamber 40b via, for example, a bifurcated flow path (not shown).

[0016] The voltage applied between the anode feeder 41 and the cathode feeder 42 is controlled by the control unit 8.

[0017] The control unit 8 is in charge of controlling each part of the electrolyzed water generation device 1. The control unit 8 has, for example, a CPU (Central Processing Unit) that executes various arithmetic processes, information processes, etc., and a memory that stores a program for controlling the operation of the CPU and various information. Various functions of the control unit 8 are realized by the CPU, the memory, and the program.

[0018] The control unit 8 performs feedback control on the electrolytic voltage applied to the anode feeder 41 and the cathode feeder 42 so that the electrolytic current supplied to the anode feeder 41 and the cathode feeder 42 becomes a desired value set in advance. For example, when the electrolytic current is excessive, the control unit 8 decreases the voltage, and when the electrolytic current is too small, the control unit 8 increases the voltage. Thereby, the electrolytic current is appropriately controlled. The electrolytic current is measured, for example, by a measuring unit provided in a circuit that supplies power to the anode feeder 41 and the cathode feeder 42.

[0019] Among the electrolyzed water electrolyzed in the electrolytic cell 4, the electrolyzed water generated in the cathode chamber 40b is sent to the tank 5 as cathode water. On the other hand, the electrolyzed water generated in the anode chamber 40a is discharged to the outside of the electrolyzed water generating device 1 as anode water.

[0020] When water is electrolyzed in the electrolytic cell 4, oxygen gas is generated in the anode chamber 40a, and hydrogen gas is generated in the cathode chamber 40b.

[0021] The oxygen gas generated in the anode chamber 40a dissolves in the electrolyzed water in the anode chamber 40a, is taken out from the anode chamber 40a as anode water, and is discharged to the outside of the electrolyzed water generating device 1.

[0022] The hydrogen gas generated in the cathode chamber 40b dissolves in the electrolyzed water in the cathode chamber 40b, is taken out from the cathode chamber 40b as cathode water, and is sent to the tank 5. That is, the cathode water sent from the cathode chamber 40b to the tank 5 is electrolyzed hydrogen water in which hydrogen gas is dissolved and electrolyzed in the cathode chamber 40b.

[0023] In FIG. 1, the tank 5 stores the electrolyzed water supplied from the electrolysis unit 3. Thereby, it becomes possible to supply a large amount of electrolyzed water to the dialysate preparation device 100 at one time. When the electrolyzed water is used for dialysis treatment, the electrolyzed water generated in the cathode chamber 40b is supplied to the tank 5. When the electrolyzed water is used for applications other than dialysis treatment, the electrolyzed water generated in the anode chamber 40a may be supplied to the tank 5.

[0024] The tank 5 is provided with a water level detection unit 6 for detecting the water level in the tank 5. The water level detection unit 6 detects the water level in the tank 5 by, for example, an optical method or buoyancy. In the present embodiment, a window portion having translucency is provided in a part of the outer wall of the tank 5, and a sensor that detects the water level without contacting the electrolyzed water using the light transmitted through the window portion is applied as the water level detection unit 6. Thereby, the generation and propagation of miscellaneous bacteria in the tank 5 can be suppressed.

[0025] In addition to the form in which the water level detection unit 6 directly detects the water level in the tank 5 using a sensor, a form in which the water level in the tank 5 is indirectly detected is also applied. As an example of the form in which the water level in the tank 5 is indirectly detected, a form including a first flow meter 11 described later can be mentioned. The first flow meter 11 detects the amount of water flowing out of the tank 5 per unit time. Since the capacity of the tank 5 is constant, the water level in the tank 5 is calculated based on the amount of water flowing out of the tank 5 per unit time.

[0026] The water level detection unit 6 transmits a signal corresponding to the detected water level to the control unit 8. The control unit 8 obtains the water level in the tank 5 based on the signal transmitted from the water level detection unit 6.

[0027] The dialysate preparation device 100 is a device for preparing a dialysate by mixing a dialysis agent with the electrolyzed water supplied from the electrolyzed water generation device 1. The dialysis agent mixed with the electrolyzed water may be in a liquid state or in a powder state. The tank 5 constituting the electrolyzed water generation device 1 is connected to the dialysate preparation device 100 so as to be able to supply electrolyzed water. In the present embodiment, a water channel 9 connecting the tank 5 and the dialysate preparation device 100 extends from the electrolyzed water generation device 1.

[0028] The dialysate prepared by the dialysate preparation device 100 is sent to a dialysis device (not shown). The dialysis device includes a dialysate supply device and a dialyzer. The dialysate supply device sends the dialysate supplied from the dialysate preparation device 100 to the dialyzer. The dialyzer is an artificial kidney including a dialysis membrane composed of a porous membrane such as a hollow fiber membrane, for example. The dialysate supplied from the dialysate preparation device 100 through the dialysis membrane acts on the blood of a patient undergoing dialysis treatment to remove waste products and moisture from the blood.

[0029] Figure 3 shows the procedure of the control method 200 of the electrolyzed water generation device 1 which is an electrolyzed water generation method using the electrolyzed water generation device 1.

[0030] The control method 200 includes a water production mode M1 and a standby mode M2 as control modes of the control unit 8. The water production mode M1 and the standby mode M2 are usually repeatedly executed alternately except when the consumption of electrolyzed water is extremely small.

[0031] The water production mode M1 is a mode in which the water supply valve 2 is opened and the electrolyzed water generated by the electrolysis unit 3 is supplied to the tank 5 to produce water. When the operation of the electrolyzed water generation device 1 starts, first, the water production mode M1 is executed. In the water production mode M1, the water supply valve 2 is opened and electrolyzed water is generated by the electrolysis unit 3. The generated electrolyzed water is supplied to the tank 5 and stored.

[0032] The standby mode M2 is a mode in which the water supply valve 2 is closed, electrolysis is not performed by the electrolysis unit 3, and the electrolyzed water is retained in the tank 5 to wait. Due to the convenience of patients and hospitals, there is usually a certain waiting time for dialysis treatment. During the waiting time, the electrolyzed water generation device 1 shifts to the standby mode M2 and waits.

[0033] In standby mode M2, when a request signal for electrolyzed water is received from an external dialysate preparation device 100 or the like of the electrolyzed water generator 1, the electrolyzed water in the tank 5 is supplied to the dialysate preparation device 100 via the water channel 9. Along with this, the electrolyzed water in the tank 5 is consumed, and the water level in the tank 5 decreases. Even during dialysis treatment, until the consumption of the electrolyzed water progresses, the electrolyzed water generator 1 waits in standby mode M2.

[0034] The dialysate is prepared immediately before dialysis treatment. On the other hand, the electrolyzed water used for preparing the dialysate is generated in advance, for example, at the opening time of the hospital (for example, in the morning). That is, initially, the control unit 8 controls the electrolyzed water generator 1 in the water production mode M1. The electrolyzed water generated in the water production mode M1 is supplied to the tank 5 and stored in the tank 5 until the dialysis treatment starts. When the electrolyzed water reaches the upper limit of the tank 5, the control unit 8 switches the control mode of the electrolyzed water generator 1 to the standby mode M2 and makes it wait.

[0035] After that, if the standby mode M2 continues for a long time, the dissolved hydrogen concentration of the electrolyzed water in the tank 5 gradually decreases. Therefore, by discharging the electrolyzed water from the tank 5 and executing the water production mode M1, the recovery of the dissolved hydrogen concentration of the electrolyzed water in the tank 5 may be achieved. In this case, the electrolyzed water discharged from the tank 5 may be returned to the electrolysis unit 3, and the electrolyzed water may be configured to circulate between the electrolysis unit 3 and the tank 5.

[0036] FIG. 4 shows the configuration of the control unit 8. The control unit 8 includes a calculation unit 81 that calculates the decreasing rate of the water level in the tank 5, a determination unit 82 that determines the timing to shift from the water production mode M1 to the standby mode M2, and a shift unit 83 that shifts the control mode. The calculation unit 81, the determination unit 82, and the shift unit 83 are realized by the cooperation of the above-described hardware such as the CPU and the memory and the program (software), but may also be realized by individual hardware circuits.

[0037] The calculation unit 81 has a function of counting time, and calculates the decrease in the water level in the tank 5 per unit time, that is, the rate of decrease in the water level, based on the signal output from the water level detection unit 6.

[0038] The determination unit 82 determines the first timing to shift from the water production mode M1 to the standby mode M2, that is, to end the water production mode M1, according to the rate of decrease in the water level in the tank 5. For example, when the rate of decrease in the water level in the tank 5 is slow, the dissolved hydrogen concentration of the electrolyzed water in the tank 5 gradually decreases. Therefore, the determination unit 82 estimates the dissolved hydrogen concentration of the electrolyzed water based on the rate of decrease in the water level in the tank 5, and determines the first timing to shift from the water production mode M1 to the standby mode M2. Note that the first timing to shift from the water production mode M1 to the standby mode M2 essentially corresponds to the water level in the tank 5 when ending the water production mode M1 and shifting to the standby mode M2.

[0039] The determination unit 82 may be configured to determine the second timing to shift from the standby mode M2 to the water production mode M1, as will be described later.

[0040] Then, the transition unit 83 shifts the control mode of the electrolyzed water generator 1 from the water production mode M1 to the standby mode M2 based on the first timing determined by the determination unit 82. That is, the transition unit 83 closes the water supply valve 2 and stops the supply of the electrolysis current to the electrolysis unit 3, thereby stopping the supply of the electrolyzed water into the tank 5.

[0041] In FIG. 3, the rate of decrease in the water level is calculated when the electrolyzed water generator 1 is in the standby mode M2. Therefore, based on the first timing determined by the determination unit 82, the transition unit 83 shifts the control mode of the electrolyzed water generator 1 from the water production mode M1 to the standby mode M2 in the second and subsequent cycles in FIG. 3.

[0042] The electrolyzed water replenished in the water production mode M1 is the water immediately generated by the electrolysis unit 3 and has a high dissolved hydrogen concentration. Therefore, in the water production mode M1 of the second and subsequent cycles, the electrolyzed water generated by the electrolysis unit 3 is replenished into the tank 5, thereby increasing the dissolved hydrogen concentration of the electrolyzed water that had decreased in the immediately preceding standby mode M2.

[0043] The dissolved hydrogen concentration of the electrolyzed water in the tank 5 in the standby mode M2 depends on the rate of decrease in the water level in the tank 5. In this electrolyzed water generation device 1, based on the first timing determined by the determination unit 82 according to the rate of decrease in the water level in the tank 5 calculated by the calculation unit 81, the transition unit 83 shifts the control mode from the water production mode M1 to the standby mode M2, whereby the water level in the tank 5 is optimized in the second and subsequent cycles, and it becomes possible to suppress the decrease in the dissolved hydrogen concentration of the electrolyzed water in the standby state.

[0044] Figure 5 shows the procedure for shifting from the water production mode M1 to the standby mode M2. The water production mode M1 and the standby mode M2 in this figure are the water production mode M1 and the standby mode M2 in the second and subsequent cycles in Figure 3.

[0045] The transition from the water production mode M1 to the standby mode M2 is realized by executing a first step S10 of calculating the rate of decrease in the water level in the tank 5, a second step S20 of determining the timing for shifting from the water production mode M1 to the standby mode M2, and a third step S30 of shifting the control mode from the water production mode M1 to the standby mode M2.

[0046] In the first step S10, based on the signal output from the water level detection unit 6, the calculation unit 81 calculates the decrease in the water level in the tank 5 per unit time, that is, the rate of decrease in the water level in the tank 5.

[0047] In the second step S20, according to the rate of decrease in the water level in the tank 5 calculated in the first step S10, the determination unit 82 determines the first timing for shifting from the water production mode M1 to the standby mode M2.

[0048] Then, in the third step S30, based on the first timing determined in the second step S20, the transfer unit 83 shifts the control mode of the electrolyzed water generator 1 from the water production mode M1 to the standby mode M2. As a result, even before the water level of the electrolyzed water reaches the upper limit of the tank 5, the replenishment of the electrolyzed water from the electrolysis unit 3 into the tank 5 is stopped.

[0049] In addition, in FIG. 5, although the first step S10 and the second step S20 are executed during the water production mode M1, depending on the processing capacity of the control unit 8, part or all of the first step S10 and the second step S20 may be executed before the water production mode M1.

[0050] As already described, the dissolved hydrogen concentration of the electrolyzed water in the tank 5 depends on the rate of decrease in the water level in the tank 5. In the control method 200 of the electrolyzed water generator 1, based on the first timing determined in the second step S20 according to the rate of decrease in the water level in the tank 5 calculated in the first step S10, by shifting the control mode from the water production mode M1 to the standby mode M2 in the third step S30, the water level in the tank 5 is optimized in the second and subsequent cycles, and it becomes possible to suppress the decrease in the dissolved hydrogen concentration of the electrolyzed water in the standby state.

[0051] In the electrolyzed water generator 1, it is desirable that the determination unit 82 is configured to determine the first timing by comparing the rate of decrease in the water level in the tank 5 with a predetermined threshold value. The above threshold value is stored, for example, by the memory of the control unit 8. It is desirable that the threshold value can be rewritten according to the usage status of the electrolyzed water, the specifications of the dialysate preparation device 100 connected to the electrolyzed water generator 1, and the like.

[0052] For example, when the rate of decrease in the water level is smaller than the above threshold value, the first timing for shifting from the water production mode M1 to the standby mode M2 is advanced with respect to a predetermined reference value so that a large amount of electrolyzed water is not stored in the tank 5. As a result, the decrease in the dissolved hydrogen concentration of the electrolyzed water in the standby state is suppressed.

[0053] On the other hand, when the rate of decrease in water level is greater than the above threshold value, the first timing for shifting from the water production mode M1 to the standby mode M2 is delayed with respect to a predetermined reference value, thereby suppressing depletion of the electrolyzed water in the tank 5.

[0054] In this case, it is desirable to be configured to determine the first timing according to the difference in the rate of decrease in water level from the above threshold value.

[0055] For example, when the difference in the rate of decrease in water level from the above threshold value is small, the difference in the first timing from the above reference value is set small, and when the difference in the rate of decrease in water level from the above threshold value is larger, the difference in the first timing from the above reference value is set large, whereby the water level in the tank 5 is controlled even better.

[0056] Similarly, in the control method 200 of the electrolyzed water generator 1, it is desirable that the second step S2 is configured to determine the first timing by comparing the rate of decrease with a predetermined threshold value.

[0057] In the electrolyzed water generator 1, it is desirable that the determination unit 82 is configured to set the first timing earlier as the rate of decrease in water level decreases.

[0058] To realize such a configuration, the above threshold value may be used, or a table showing the relationship between the rate of decrease in water level and the first timing may be used. The table is stored, for example, in the memory of the control unit 8.

[0059] FIG. 6 shows an example of the above table. In the table of this figure, a form in which the rate of decrease in water level and the first timing are in a proportional relationship (linear) is shown. A form in which the rate of decrease in water level and the first timing are in a relationship represented by a curve such as a quadratic function, an exponential function, or a logarithmic function may also be used.

[0060] Similarly, in the control method 200 of the electrolyzed water generator 1, it is desirable that the second step S2 is configured to set the first timing earlier as the decrease rate becomes smaller.

[0061] In the operation of the hospital, the number of hemodialysis patients may temporarily increase, and the amount of dialysate used may also increase. In such a case, the decrease rate of the water level in the tank 5 becomes large. Therefore, in the electrolyzed water generator 1, the determination unit 82 may be configured to set the first timing later as the decrease rate of the water level becomes large. Similarly, in the control method 200 of the electrolyzed water generator 1, the second step S2 may be configured to set the first timing later as the decrease rate becomes large.

[0062] In order to realize such a configuration, the above threshold value may be used, or a table showing the relationship between the decrease rate of the water level and the first timing may be used.

[0063] FIG. 7 shows the configuration of the water level detection unit 6 together with the tank 5.

[0064] The water level detection unit 6 includes a first sensor 61 for detecting the upper limit value of the water level in the tank 5 and a second sensor 62 for detecting the lower limit value of the water level in the tank 5.

[0065] The first sensor 61 is arranged at the upper part of the tank 5. The position of the first sensor 61 is the position set as the upper limit of the water level in the tank 5, but it is not limited to the upper end of the tank 5.

[0066] The water production mode M1 in the first cycle in FIG. 3 is executed until the first sensor 61 detects the electrolyzed water reaching the upper limit of the water level in the tank. When the first sensor 61 detects the electrolyzed water, the control unit 8 shifts the control mode from the water production mode M1 to the standby mode M2 (see FIG. 3). Thereby, the tank 5 is filled with electrolyzed water up to the upper limit of its capacity.

[0067] The second sensor 62 is arranged, for example, at the height of the lower part of the tank 5, although it also depends on the specifications of the electrolyzed water generator 1, the capacity of the tank 5, and the specifications of the dialysate preparation device 100 connected to the electrolyzed water generator 1. The position of the second sensor 62 is set as the lower limit of the water level in the tank 5, but it is not limited to the lower end of the tank 5.

[0068] More specifically, even when the electrolyzed water in the tank 5 is rapidly consumed, considering the capacity of the tank 5, the specifications of the dialysate preparation device 100, and further, the number of patients being treated simultaneously, etc., the height of the second sensor 62 from the inner bottom surface of the tank 5 is determined so that the electrolyzed water does not run out.

[0069] In such a configuration, the calculation unit 81 can calculate the rate of decrease of the water level in the tank 5 based on the outputs from the first sensor 61 and the second sensor 62. More specifically, the calculation unit 81 can calculate the rate of decrease of the water level in the tank 5 in the standby mode M2 by counting the time from when the first sensor 61 detects the water level until the second sensor 62 detects the water level.

[0070] The detection by the second sensor 62 that the water level is at the lower limit value can be used as a trigger to shift from the standby mode M2 to the water production mode M1. That is, the determination unit 82 determines the second timing to shift from the standby mode M2 to the water production mode M1 based on the output from the second sensor 62 in the standby mode M2. Then, the transition unit 83 shifts the control mode from the standby mode M2 to the water production mode M1 based on the second timing determined by the determination unit 82. Thereby, depletion of the electrolyzed water in the tank 5 can be suppressed.

[0071] FIG. 8 is a cross-sectional view of a water level detection unit 6A which is a modification of the water level detection unit 6 in FIG. 7. For the parts not described below in the water level detection unit 6A, the configuration of the above-described water level detection unit 6 can be adopted.

[0072] The water level detection unit 6A is different from the water level detection unit 6 in that it includes the third sensor 63. The third sensor 63 is a sensor for detecting the water level at an intermediate value between the upper limit value and the lower limit value. For this reason, the third sensor 63 is arranged at a height between the first sensor 61 and the second sensor 62.

[0073] In such a configuration, the calculation unit 81 can calculate the rate of decrease in the water level in the tank 5 based on the outputs from the third sensor 63 and the second sensor 62. More specifically, the calculation unit 81 can calculate the rate of decrease in the water level in the tank 5 in the latter half of the standby mode M2 (that is, closer to the present) by counting the time from when the third sensor 63 detects the water level until the second sensor 62 detects the water level.

[0074] In the water level detection unit 6A shown in FIG. 8, the transition unit 83 can shift the control mode from the water production mode to the standby mode based on the output from the first sensor 61 or the third sensor 63 in the water production mode M1.

[0075] For example, when the rate of decrease in the water level is smaller than the threshold value and the first timing is set earlier, the transition unit 83 shifts the control mode from the water production mode M1 to the standby mode M2 when the third sensor 63 detects the water level of the electrolyzed water in the water production mode M1 (that is, when the water production reaches the water level of the third sensor 63). Thereby, the amount of electrolyzed water stored in the tank 5 is limited, the time in the subsequent standby state is shortened, and a decrease in the dissolved hydrogen concentration of the electrolyzed water can be suppressed.

[0076] On the other hand, when the rate of decrease in the water level is larger than the threshold value and the first timing is set later, the transition unit 83 shifts the control mode from the water production mode M1 to the standby mode M2 when the first sensor 61 detects the water level of the electrolyzed water in the water production mode M1 (that is, when the water production reaches the water level of the first sensor 61). Thereby, depletion of the electrolyzed water in the tank 5 can be suppressed.

[0077] FIG. 9 is a cross-sectional view of a water level detection unit 6B, which is a modification of the water level detection unit 6A in FIG. 8. For parts of the water level detection unit 6B not described below, the configuration of the water level detection unit 6 and the like described above may be adopted.

[0078] The water level detection unit 6B is different from the water level detection unit 6A in that it includes a plurality of third sensors 63. In the water level detection unit 6B of the present embodiment, the third sensors 63 are constituted by three third sensors 63a, 63b, and 63c. In the water level detection unit 6B, the number of the third sensors 63 is not particularly limited as long as it is 2 or more.

[0079] In the water level detection unit 6B, the rate of decrease of the water level in the tank 5 can be calculated based on the output from any of the third sensors 63a, 63b, and 63c.

[0080] In this case, it is desirable that the calculation unit 81 calculates the rate of decrease of the water level in the tank 5 based on the output from the third sensor 63c at the height closest to the second sensor 62 and the second sensor 62. Thereby, the calculation unit 81 can calculate the rate of decrease of the water level in the tank 5 most recently.

[0081] According to the water level detection unit 6B, the water level of the electrolyzed water can be obtained step by step. Thereby, even when performing hemodialysis treatment for a large number of people simultaneously, it is possible to suppress a shortage of the electrolyzed water used for preparing the dialysate.

[0082] Further, when the calculation unit 81 calculates the rate of decrease of the water level in the tank 5 based on the outputs from the plurality of third sensors 63a, 63b, 63c and the second sensor 62, the transition of the rate of decrease of the water level is calculated, and the determination unit 82 can determine the first timing based on the tendency of the change in the rate of decrease of the water level.

[0083] In the water level detection unit 6B shown in FIG. 9, the transition unit 83 can shift the control mode from the water production mode M1 to the standby mode M2 based on the output from the first sensor 61 or the third sensors 63a, 63b, 63c in the water production mode M1.

[0084] For example, when the rate of decrease in the water level is extremely slow, the transition unit 83 can reduce the amount of electrolyzed water stored in the tank 5 by shifting the control mode from the water production mode M1 to the standby mode M2 based on the output from the third sensor 63c. On the other hand, when the rate of decrease in the water level is slightly faster, the transition unit 83 can increase the amount of electrolyzed water stored in the tank 5 by shifting the control mode from the water production mode M1 to the standby mode M2 based on the output from the third sensor 63a. In this way, it is possible to stepwise adjust the amount of electrolyzed water stored in the tank 5 according to the rate of decrease in the water level, that is, the consumption rate of electrolyzed water, and further suppress the decrease in the dissolved hydrogen concentration of electrolyzed water in the standby state.

[0085] In the electrolyzed water generator 1 to which the water level detection unit 6B is applied, the table shown in FIG. 6 is in a form in which the first timing increases stepwise in accordance with the increase in the rate of decrease, and the timing at which the output of any one of the third sensors 63a, 63b, 63c is received corresponds to each step.

[0086] FIG. 10 is a block diagram showing the configuration of an electrolyzed water generator 1A which is a modified example of the electrolyzed water generator 1 of FIG. 1. For the parts not described below in the electrolyzed water generator 1A, the configuration of the above-described electrolyzed water generator 1 may be adopted.

[0087] In the electrolyzed water generator 1A, the water level detection unit 6C includes a first flow meter 11 for detecting the amount of water flowing out of the tank 5 per unit time. The first flow meter 11 of the present embodiment is arranged in the water passage 9 from the tank 5 to the dialysate preparation device 100, but is not limited to such an arrangement. For example, it may be arranged integrally with the tank 5. The first flow meter 11 transmits a signal corresponding to the detected amount of flowing water to the control unit 8.

[0088] The control unit 8 stores specifications of the tank 5, particularly information regarding the capacity. Therefore, in the electrolyzed water generator 1A, the calculation unit 81 can calculate the water level in the tank 5 and its decreasing rate based on the signal input from the first flow meter 11. With such a configuration, when calculating the decreasing rate of the water level in the tank 5, configurations such as the first sensor 61 to the third sensor 63 shown in FIGS. 7 to 9 become unnecessary.

[0089] FIG. 11 is a block diagram showing the configuration of an electrolyzed water generator 1B, which is another modification of the electrolyzed water generator 1 in FIG. 1. For parts not described below in the electrolyzed water generator 1B, the configurations of the above-described electrolyzed water generator 1 and the like can be adopted.

[0090] The electrolyzed water generator 1B further includes a second flow meter 12 for detecting the supply amount of raw water supplied to the electrolysis unit 3. The second flow meter 12 of the present embodiment is arranged in the water passage between the water supply valve 2 and the electrolysis unit 3, but is not limited to such an arrangement. For example, it may be arranged integrally with the electrolysis unit 3. The second flow meter 12 transmits a signal corresponding to the detected water supply amount to the control unit 8.

[0091] In the electrolyzed water generator 1B, as the water level detection unit 6 for detecting the water level in the tank 5, in addition to the first sensor 61, the second sensor 62, the third sensors 63, 63a, 63b, 63c, the first flow meter 11 can also be applied.

[0092] In the electrolyzed water generator 1B, the transition unit 83 calculates the water level in the tank 5 based on the output from the second flow meter 12. Then, the transition unit 83 shifts the control mode from the water production mode M1 to the standby mode M2 at the water level corresponding to the first timing determined by the determination unit 82. Thereby, it becomes possible to adjust the amount of electrolyzed water stored in the tank 5 according to the decreasing rate of the water level, that is, the consumption rate of the electrolyzed water, and further suppress the decrease in the dissolved hydrogen concentration of the electrolyzed water in the standby state. In addition, since the amount of electrolyzed water stored in the tank 5 in the water production mode M1 can be adjusted steplessly, the decrease in the dissolved hydrogen concentration of the electrolyzed water can be suppressed more precisely.

[0093] In the electrolyzed water generation device 1B, in the table shown in FIG. 6, the first timing is controlled by the supply amount of raw water supplied to the electrolysis unit 3.

[0094] In the electrolyzed water generation device 1B, the second flowmeter 12 may be configured to detect the supply amount of the electrolyzed water supplied from the electrolysis unit 3 to the tank 5. In this case, the second flowmeter 12 is arranged, for example, between the electrolysis unit 3 and the tank 5.

[0095] FIG. 12 is a block diagram showing the configuration of an electrolyzed water generation device 1C, which is still another modified example of the electrolyzed water generation device 1 in FIG. 1. For the parts not described below in the electrolyzed water generation device 1C, the configurations of the above-described electrolyzed water generation device 1 and the like may be adopted.

[0096] The electrolyzed water generation device 1C further includes a timer 13 that counts time. The clock function provided in the control unit 8 may be applied to the timer 13. The timer 13 counts the time when the water production mode M1 is executed, that is, the water production time.

[0097] Also in the electrolyzed water generation device 1C, as the water level detection unit 6 for detecting the water level in the tank 5, in addition to the first sensor 61 or the third sensors 63a, 63b, 63c, the first flowmeter 11 may be applied.

[0098] Raw water is supplied to the electrolysis unit 3 at a constant supply amount. In this embodiment, the water supply valve 2 supplies raw water at a constant supply amount to the electrolysis unit 3.

[0099] In the electrolyzed water generator 1C, since the water supply amount to the electrolysis unit 3 is constant, the transfer unit 83 can calculate the water level in the tank 5 based on the water production time counted by the timer 13. Then, the transfer unit 83 shifts the control mode from the water production mode M1 to the standby mode M2 at the water level corresponding to the first timing determined by the determination unit 82. Thereby, according to the decreasing speed of the water level, that is, the consumption speed of the electrolyzed water, the amount of the electrolyzed water stored in the tank 5 can be adjusted, and it becomes possible to further suppress the decrease in the dissolved hydrogen concentration of the electrolyzed water in the standby state. Also, since the amount of the electrolyzed water stored in the tank 5 can be adjusted steplessly in the water production mode M1, the decrease in the dissolved hydrogen concentration of the electrolyzed water can be suppressed more precisely.

[0100] In the electrolyzed water generator 1C, in the table shown in FIG. 6, the first timing is controlled by the time when the water production mode M1 is executed.

[0101] When the water level detection unit 6A is applied as the water level detection unit 6 in the electrolyzed water generators 1B and 1C, the determination unit 82 determines the first timing so that the water level in the tank 5 becomes equal to or higher than the third sensor 63. Thereby, in the next cycle, the decreasing speed of the water level can be appropriately calculated. Similarly, when the water level detection unit 6B is applied as the water level detection unit 6 in the electrolyzed water generators 1B and 1C, the determination unit 82 determines the first timing so that the water level in the tank 5 becomes equal to or higher than the third sensor 63c.

[0102] As described above, the electrolyzed water generator 1 of the present invention has been described in detail. However, the present invention is not limited to the above specific embodiments and can be implemented with various modifications.

[0103] For example, it is desirable that the dialysis fluid preparation device 100 is configured to be supplied with electrolyzed water purified by reverse osmosis treatment. As a form for realizing such a configuration, in FIG. 1, a reverse osmosis treatment device including a reverse osmosis membrane module is arranged upstream of the electrolyzed water generation device 1 or in a system arranged between the electrolyzed water generation device 1 and the dialysis fluid preparation device 100. Further, the reverse osmosis treatment device may be incorporated inside the electrolyzed water generation device 1 (for example, upstream of the electrolysis unit 3, between the electrolysis unit 3 and the tank 5, or downstream of the tank 5). When reverse osmosis treated water is applied as the raw water supplied to the electrolyzed water generation device 1, the above-described reverse osmosis treatment device may not be necessary.

[0104] [Appendix] The present invention includes the following aspects.

[0105] [Invention 1] An electrolyzed water generation device, a water supply valve for controlling the supply of raw water, an electrolysis unit for generating electrolyzed water by electrolyzing the raw water supplied from the water supply valve, a tank for storing the electrolyzed water generated by the electrolysis unit, a water level detection unit for detecting the water level in the tank, and a control unit for controlling the water supply valve and the electrolysis unit, wherein the control unit has, as control modes, a water production mode in which the water supply valve is opened and the electrolyzed water generated by the electrolysis unit is supplied to the tank, a standby mode in which the water supply valve is closed and standby is performed without performing electrolysis in the electrolysis unit, the water production mode and the standby mode are alternately and repeatedly executed, The control unit includes a calculation unit that calculates a decrease rate of the water level in the tank based on an output from the water level detection unit, a determination unit that determines a first timing to shift from the water production mode to the standby mode according to the decrease rate, and a shift unit that shifts the control mode from the water production mode to the standby mode based on the first timing. Electrolyzed water generator. [Invention 2] The electrolyzed water generator according to Invention 1, wherein the determination unit determines the first timing by comparing the decrease rate with a predetermined threshold value. [Invention 3] The electrolyzed water generator according to Invention 1, wherein the determination unit sets the first timing earlier as the decrease rate becomes smaller. [Invention 4] The electrolyzed water generator according to Invention 1, wherein the determination unit sets the first timing later as the decrease rate becomes larger. [Invention 5] The electrolyzed water generator according to any one of Inventions 1 to 4, wherein the water level detection unit includes a first sensor for detecting an upper limit value of the water level and a second sensor for detecting a lower limit value of the water level. [Invention 6] The electrolyzed water generator according to Invention 5, wherein the shift unit shifts the control mode from the standby mode to the water production mode based on an output from the second sensor in the standby mode. [Invention 7] The water level detection unit includes a third sensor for detecting the water level at an intermediate value between the upper limit value and the lower limit value, The electrolyzed water generator according to Invention 5, wherein the calculation unit calculates the decrease rate of the water level in the tank based on outputs from the third sensor and the second sensor. [Invention 8] The water level detection unit includes a plurality of the third sensors, The calculation unit calculates the rate of decrease of the water level in the tank based on the output from the third sensor at the height closest to the second sensor and the second sensor, of the electrolyzed water generation device according to the seventh aspect of the present invention. [The ninth aspect of the present invention] The transition unit shifts the control mode from the water production mode to the standby mode based on the output from the first sensor or the third sensor in the water production mode, of the electrolyzed water generation device according to the seventh aspect of the present invention. [The tenth aspect of the present invention] The water level detection unit includes a first flow meter for detecting the amount of water flowing out of the tank. The calculation unit calculates the rate of decrease of the water level in the tank based on the output from the first flow meter, of the electrolyzed water generation device according to any one of the first to fourth aspects of the present invention. [The eleventh aspect of the present invention] The water level detection unit includes a first sensor for detecting the upper limit value of the water level, a second sensor for detecting the lower limit value of the water level, and a third sensor for detecting the water level at an intermediate value between the upper limit value and the lower limit value. The transition unit shifts the control mode from the water production mode to the standby mode based on the output from the first sensor or the third sensor in the water production mode, of the electrolyzed water generation device according to any one of the first to fourth aspects of the present invention. [The twelfth aspect of the present invention] The electrolysis unit further includes a second flow meter for detecting the supply amount of the raw water supplied to the electrolysis unit. The transition unit shifts the control mode from the water production mode to the standby mode based on the output from the second flow meter, of the electrolyzed water generation device according to any one of the first to fourth aspects of the present invention. [The thirteenth aspect of the present invention] The raw water is supplied to the electrolysis unit at a constant supply amount. The electrolysis unit further includes a timer for counting time. The transition unit shifts the control mode from the water production mode to the standby mode based on the water production time in the water production mode counted by the timer, of the electrolyzed water generation device according to any one of the first to fourth aspects of the present invention. [Invention 14] A control method for an electrolyzed water generator, wherein the electrolyzed water generator comprises: a water supply valve for controlling the supply of raw water; an electrolysis unit for generating electrolyzed water by electrolyzing the raw water supplied from the water supply valve; a tank for storing the electrolyzed water generated by the electrolysis unit; a water level detection unit for detecting the water level in the tank; and a control unit for controlling the water supply valve and the electrolysis unit, wherein the control method includes: a water production mode in which the water supply valve is opened and the electrolyzed water generated by the electrolysis unit is supplied to the tank; a standby mode in which the water supply valve is closed and the electrolysis unit waits without performing electrolysis, wherein the water production mode and the standby mode are alternately and repeatedly executed, a first step of calculating a decrease rate of the water level in the tank based on an output from the water level detection unit; a second step of determining a first timing for shifting from the water production mode to the standby mode according to the decrease rate; and a third step of shifting from the water production mode to the standby mode based on the first timing. A control method for an electrolyzed water generator. [Invention 15] The control method for an electrolyzed water generator according to Invention 14, wherein in the second step, the first timing is determined by comparing the decrease rate with a predetermined threshold value. [Invention 16] The control method for an electrolyzed water generator according to Invention 15, wherein in the second step, the first timing is set earlier as the decrease rate becomes smaller. [Invention 17] The control method for an electrolyzed water generator according to Invention 15, wherein in the second step, the first timing is set later as the decrease rate becomes larger. [Invention 18] The water level detection unit includes a first sensor for detecting the upper limit value of the water level and a second sensor for detecting the lower limit value of the water level. The third step is the control method of the electrolyzed water generator according to any one of claims 14 to 17 of the present invention, which shifts the control mode from the standby mode to the water production mode based on the output from the second sensor in the standby mode.

Explanation of Signs

[0106] 1: Electrolyzed water generator 1A: Electrolyzed water generator 1B: Electrolyzed water generator 1C: Electrolyzed water generator 2: Water supply valve 3: Electrolysis unit 5: Tank 6: Water level detection unit 6A: Water level detection unit 6B: Water level detection unit 6C: Water level detection unit 8: Control unit 11: First flow meter 12: Second flow meter 13: Timer 61: First sensor 62: Second sensor 63: Third sensor 63a: Third sensor 63b: Third sensor 63c: Third sensor 81: Calculation unit 82: Decision unit 83: Transition unit 200: Control method M1: Standby mode M1: Water production mode M2: Standby mode S10: First step S20: Second step S30: Third step

Claims

1. An electrolyzed water generating apparatus, comprising: a water supply valve for controlling the supply of raw water; an electrolysis unit for generating electrolyzed water by electrolyzing the raw water supplied from the water supply valve; a tank for storing the electrolyzed water generated by the electrolysis unit; a water level detection unit for detecting the water level in the tank; and a control unit for controlling the water supply valve and the electrolysis unit, wherein the control unit has, as control modes: a water production mode in which the water supply valve is opened and the electrolyzed water generated by the electrolysis unit is supplied to the tank; and a standby mode in which the water supply valve is closed and electrolysis is not performed by the electrolysis unit and the apparatus waits, the water production mode and the standby mode are alternately and repeatedly executed, and the control unit includes a calculation unit for calculating a decrease rate of the water level in the tank based on an output from the water level detection unit, a determination unit for determining a first timing for shifting from the water production mode to the standby mode according to the decrease rate, and a shift unit for shifting the control mode from the water production mode to the standby mode based on the first timing. An electrolyzed water generating apparatus.

2. The electrolyzed water generating apparatus according to claim 1, wherein the determination unit determines the first timing by comparing the decrease rate with a predetermined threshold value.

3. The electrolyzed water generating apparatus according to claim 1, wherein the determination unit sets the first timing earlier as the decrease rate becomes smaller.

4. The electrolyzed water generating apparatus according to claim 1, wherein the determination unit sets the first timing later as the decrease rate becomes larger.

5. The electrolyzed water generating apparatus according to any one of claims 1 to 4, wherein the water level detection unit includes a first sensor for detecting an upper limit value of the water level and a second sensor for detecting a lower limit value of the water level.

6. The electrolyzed water generating apparatus according to claim 5, wherein the shift unit shifts the control mode from the standby mode to the water production mode based on an output from the second sensor in the standby mode.

7. The water level detection unit includes a third sensor for detecting the water level at an intermediate value between the upper limit value and the lower limit value, and the calculation unit calculates the decrease rate of the water level in the tank based on outputs from the third sensor and the second sensor.

8. The water level detection unit includes a plurality of the third sensors, The calculation unit calculates a decrease rate of the water level in the tank based on the third sensor at the height closest to the second sensor and an output from the second sensor. The electrolyzed water generator according to claim 7.

9. The transition unit shifts the control mode from the water production mode to the standby mode based on an output from the first sensor or the third sensor in the water production mode. The electrolyzed water generator according to claim 7.

10. The water level detection unit includes a first flow meter for detecting an amount of water flowing out of the tank, The calculation unit calculates a decrease rate of the water level in the tank based on an output from the first flow meter. The electrolyzed water generator according to any one of claims 1 to 4.

11. The water level detection unit includes a first sensor for detecting an upper limit value of the water level, a second sensor for detecting a lower limit value of the water level, and a third sensor for detecting the water level at an intermediate value between the upper limit value and the lower limit value, The transition unit shifts the control mode from the water production mode to the standby mode based on an output from the first sensor or the third sensor in the water production mode. The electrolyzed water generator according to any one of claims 1 to 4.

12. The electrolyzed water generator further includes a second flow meter for detecting a supply amount of the raw water supplied to the electrolysis unit, The transition unit shifts the control mode from the water production mode to the standby mode based on an output from the second flow meter. The electrolyzed water generator according to any one of claims 1 to 4.

13. The raw water is supplied to the electrolysis unit at a constant supply amount, The electrolyzed water generator further includes a timer for counting time, The transition unit shifts the control mode from the water production mode to the standby mode based on a water production time in the water production mode counted by the timer. The electrolyzed water generator according to any one of claims 1 to 4.

14. A control method for an electrolyzed water generator, The electrolyzed water generator includes A water supply valve for controlling the supply of raw water, An electrolysis unit for generating electrolyzed water by electrolyzing the raw water supplied from the water supply valve, A tank for storing the electrolyzed water generated by the electrolysis unit, A water level detection unit for detecting the water level in the tank, A control unit for controlling the water supply valve and the electrolysis unit, The control method is A water production mode in which the water supply valve is opened and the electrolyzed water generated by the electrolysis unit is supplied to the tank, A standby mode in which the water supply valve is closed and electrolysis is not performed by the electrolysis unit and standby is performed, The water production mode and the standby mode are alternately and repeatedly executed, A first step of calculating a decrease rate of the water level in the tank based on an output from the water level detection unit, a second step of determining a first timing for shifting from the water production mode to the standby mode according to the decrease rate, and a third step of shifting from the water production mode to the standby mode based on the first timing. A control method for an electrolyzed water generator.

15. The control method for an electrolyzed water generator according to claim 14, wherein the second step determines the first timing by comparing the decrease rate with a predetermined threshold value.

16. The control method for an electrolyzed water generator according to claim 15, wherein the second step sets the first timing earlier as the decrease rate decreases.

17. The control method for an electrolyzed water generator according to claim 15, wherein the second step sets the first timing later as the decrease rate increases.

18. The water level detection unit includes a first sensor for detecting an upper limit value of the water level and a second sensor for detecting a lower limit value of the water level, The control method for an electrolyzed water generator according to any one of claims 14 to 17, wherein the third step shifts the control mode from the standby mode to the water production mode based on an output from the second sensor in the standby mode.

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