Water supply system

Abstract

To provide a technique for suppressing concentration variations of specific components in diluted water.SOLUTION: A water supply system includes a water supply channel 50 through which raw water flows, an undiluted solution channel 62 into which an undiluted solution supplied from a liquid source is added to the raw water flowing through the water supply channel, a pumping part 64 installed in the undiluted solution channel 62 to pump the undiluted solution into the water supply channel 50, a flow sensor 66 installed in the water supply channel 50, and a control part 86 that controls, based on the detected value of the raw water flow rate, the flow rate of the undiluted solution being pumped from the pumping part 64 so that the concentration of a specific component of the undiluted solution in diluted water generated by adding the undiluted solution to the raw water becomes a target concentration.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to water supply systems. [Background technology]

[0002] Patent Document 1 discloses a water supply system including a water supply flow path through which raw water flows, a raw liquid flow path that adds raw liquid supplied from a liquid source to the raw water flowing through the water supply flow path, a liquid delivery unit provided in the raw liquid flow path, and a concentration sensor provided in the water supply flow path that detects the concentration of a specific component. The water supply system of Patent Document 1 controls the flow rate of the raw liquid delivered from the liquid delivery unit based on the detection value of the concentration sensor, thereby controlling the concentration of the specific component in the dilution water to a target concentration. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 11-90458 Summary of the Invention [Problem to be solved by the invention]

[0004] When the flow rate of raw water flowing through the water supply flow path fluctuates, the concentration of a specific component of the raw water in the dilution water varies. The inventors of the present application have discovered a new idea for suppressing the variation in the concentration of the specific component of the raw water in the dilution water in such cases.

[0005] One of the objects of the present disclosure is to provide a technique for suppressing variation in the concentration of a specific component in dilution water. [Means for solving the problem]

[0006] The water supply system of the present disclosure comprises a water supply flow path through which raw water flows, a raw liquid flow path that adds raw liquid supplied from a liquid source to the raw water flowing through the water supply flow path, a liquid delivery unit provided in the raw liquid flow path that delivers the raw liquid to the water supply flow path, a flow rate sensor provided in the water supply flow path, and a control unit that controls the flow rate of the raw liquid delivered from the liquid delivery unit based on a detection value indicating the raw water flow rate detected by the flow rate sensor so that the concentration of a specific component of the raw liquid in diluted water produced by adding the raw liquid to the raw water becomes a target concentration. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is a schematic overall configuration diagram of a water supply system according to an embodiment of the present invention; [Figure 2] 4 is a timing chart for explaining the operation of the water supply system of the present embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0008] The following describes the embodiments. Identical components are designated by the same reference numerals, and redundant explanations will be omitted. In each drawing, components are omitted, enlarged, or reduced as appropriate for the sake of convenience. The drawings should be viewed in accordance with the orientation of the reference numerals.

[0009] Please refer to FIG. 1. The water supply system 10 is used to supply dilution water (described later) to a water-receiving portion 12. In this embodiment, the water-receiving portion 12 is a water discharge portion of a water discharge device that discharges dilution water. Here, a water discharge pipe is shown as an example of the water discharge device. Alternatively, the water discharge device may be, for example, a shower head. Specific examples of the water-receiving portion 12 are not particularly limited, and may also be a tank for storing dilution water.

[0010] The water supply system 10 includes a first water supply line 16 for supplying dilution water to the water-receiving portion 12, and a second water supply line 18 for supplying hot and cold water mixed water, which is a different type of water from the dilution water, to the water-receiving portion 12. Both the first water supply line 16 and the second water supply line 18 supply drinking water (dilution water, hot and cold water mixed water).

[0011] The second water supply line 18 includes a water flow path 22 to which room-temperature tap water is supplied from a water supply source 20 such as a waterworks system; a hot water flow path 26 to which hot water is supplied from a hot water source 24 such as a water heater; a mixing valve 28 that mixes the room-temperature water and hot water supplied from the water flow path 22 and the hot water flow path 26; and a mixed water flow path 30 that supplies the mixed hot water and hot water mixed by the mixing valve 28 to the water-supplied portion 12. The mixing ratio of room-temperature water and hot water in the mixing valve 28 and the flow rate of the mixed hot water and hot water supplied from the mixing valve 28 can be controlled by a single lever 32 provided on the water discharge device 14. The water flow path 22 is provided with a first check valve 38 and a second check valve 40 spaced apart in the flow direction to prevent backflow upstream. The hot water flow path 26 is provided with a third check valve 42 to prevent backflow upstream.

[0012] The first water supply line 16 includes a water supply flow path 50 that branches off from the water flow path 22 and leads to the water-receiving portion 12, a reforming cartridge 52 provided in the water supply flow path 50, a bypass flow path 54 that branches off from the water supply flow path 50 to avoid the reforming cartridge 52 and joins the water supply flow path 50, and a switching valve 56 such as a three-way valve provided at the branch point between the water supply flow path 50 and the bypass flow path 54. The switching valve 56 can switch the flow destination of raw water between the cartridge via portion of the water supply flow path 50 that passes through the reforming cartridge 52 and the bypass flow path 54. When dilution water is supplied to the water-receiving portion 12, the switching valve 56 switches the flow destination of the raw water so that it passes through the reforming cartridge 52. When the flow path portion downstream of the confluence of the water supply flow path 50 and the bypass flow path 54 is cleaned with chlorinated tap water as raw water, the switching valve 56 switches the flow destination of the raw water so that it passes through the bypass flow path 54.

[0013] The first water supply line 16 also includes a liquid source 60 for storing the concentrate, a concentrate flow path 62 connected to the water supply flow path 50, a liquid delivery section 64 provided in the concentrate flow path 62, a flow rate sensor 66 provided in the water supply flow path 50, and an opening / closing valve 68 provided in the water supply flow path 50.

[0014] Raw water to which water supply pressure is applied is supplied from the upstream water supply source 20 to the water supply flow path 50. In this embodiment, raw water is supplied from the water supply source 20 via the water flow path 22 to the water supply flow path 50. At the confluence 70 of the water supply flow path 50 and the concentrate flow path 62, the concentrate is added to the raw water to produce diluted water in which the concentrate is diluted with the raw water. The diluted water flows downstream of the confluence 70 of the water supply flow path 50 and the concentrate flow path 62 and is supplied to the water-receiving portion 12. Here, "raw water" refers to the solvent to which the concentrate is added. It does not matter whether the "raw water" has been modified by passing through the modification cartridge 52. The raw water may be tap water containing chlorine components, natural water, or the like.

[0015] A fourth check valve 72 is provided in the water supply flow path 50 upstream of the confluence 70 between the water supply flow path 50 and the raw solution flow path 62, to prevent backflow upstream. A constant flow valve 74 is provided in the water supply flow path 50 upstream of the on-off valve 68, to limit the flow rate of raw water flowing through the water supply flow path 50 to a set flow rate or less.

[0016] The reforming cartridge 52 has a portion of the water supply flow path 50 disposed therein and is capable of reforming the raw water flowing through it. Here, "reforming" refers to removing or adding specific components to the raw water through physical or chemical changes. The reforming cartridge 52 of this embodiment is a water purification cartridge that removes chlorine components contained in tap water that flows in as raw water, and produces purified water by purifying the raw water. In addition, the raw water may be reformed by adding beauty components, fragrance components, carbon dioxide components, hydrogen components, etc. to the raw water. The reforming cartridge 52 is detachably held in a cartridge holder (not shown). The water supply system 10 does not necessarily have to include the reforming cartridge 52.

[0017] The liquid source 60 is detachably held in a concentrate holder (not shown). Specific examples of the liquid source 60 are not particularly limited, and various containers, tanks, etc. may be used. The concentrate is used for drinking purposes, such as a dilution concentrate for beverages, a food additive concentrate, or a seasoning liquid. In addition, the concentrate may be used for purposes that come into contact with the human body, such as soapy water, lotion, or body oil. Such uses that come into contact with the human body include the aforementioned dilution concentrate for beverages that are used for drinking.

[0018] The raw liquid supplied from the liquid source 60 flows through the raw liquid flow path 62, and the raw liquid is added to the raw water flowing through the water supply flow path 50. A fifth check valve 76 is provided in the raw liquid flow path 62 upstream of the liquid delivery section 64. The fifth check valve 76 prevents outside air from flowing downstream in the raw liquid flow path 62. A sensor 78 is provided in the raw liquid flow path 62 to detect the presence or absence of raw liquid in the raw liquid flow path 62.

[0019] A sixth check valve 80 is provided in the raw liquid flow path 62 downstream of the liquid delivery unit 64. The sixth check valve 80 prevents backflow upstream in the raw liquid flow path 62. This prevents microorganisms and other contaminants in the raw water of the water supply path 50 from flowing upstream of the sixth check valve 80 into the raw liquid flow path 62, thereby maintaining the sanitary condition of the raw liquid in the raw liquid flow path 62. The sixth check valve 80 is configured to open and close without a power source in conjunction with the presence or absence of liquid delivery by the liquid delivery unit 64. To achieve this, the sixth check valve 80 is configured to open due to the internal pressure of the raw liquid acting from the upstream side when the liquid delivery unit 64 is delivering liquid, and to close due to the internal pressure of the liquid (raw water, etc.) acting from the downstream side when the liquid delivery unit 64 is not delivering liquid. The sixth check valve 80 may be any of a variety of check valves, such as a duckbill valve.

[0020] The stock solution flow path 62 is provided with a sterilization unit 82 that sterilizes the stock solution flowing through the stock solution flow path 62. The sterilization unit 82 has a part of the stock solution flow path 62 provided therein, and sterilizes the stock solution that flows through the stock solution flow path 62 via the sterilization unit 82. The sterilization unit 82 is configured to sterilize the stock solution using, for example, a hollow fiber membrane filter, a photocatalyst, ultraviolet light, or the like.

[0021] The liquid delivery unit 64 delivers the raw liquid by sucking the raw liquid from the liquid source 60 side and discharging it toward the water supply flow path 50 side. The liquid delivery unit 64 of this embodiment is driven by a drive voltage or drive current supplied from the control unit 86 (described later) and continuously delivers the raw liquid so as to achieve an instantaneous flow rate of the raw liquid (hereinafter referred to as the raw liquid flow rate) corresponding to the drive voltage or drive current. Here, an example in which the liquid delivery unit 64 is driven by a drive voltage will be described. To achieve this, the liquid delivery unit 64 of this embodiment includes a pump and a motor for driving the pump. The flow rate of the raw liquid delivered from the pump can be increased as the voltage value of the drive voltage for driving the motor increases. Alternatively, the liquid delivery unit 64 may include, for example, a solenoid for driving the pump in addition to the pump, allowing the raw liquid flow rate to be changed according to the drive current for driving the solenoid. While the pump of the liquid delivery unit 64 of this embodiment is a tube pump, various other pumps, such as a gear pump or a vane pump, may also be used. The liquid delivery section 64 in this embodiment is configured using a pump, but the specific example is not particularly limited, and may be, for example, a compressor or the like.

[0022] The flow rate sensor 66 of this embodiment is provided in the water supply flow path 50 upstream of the junction 70 with the raw solution flow path 62. The flow rate sensor 66 of this embodiment is also provided in the water supply flow path 50 upstream of the branch point 84 with the bypass flow path 54. The flow rate sensor 66 detects the instantaneous flow rate of raw water flowing through the water supply flow path 50 (hereinafter referred to as the raw water flow rate) and outputs a detected value indicating the raw water flow rate to the control unit 86. In this specification, the term "flow rate" refers to the volumetric flow rate (L / min) of the subject of reference. There are no particular limitations on the specific example of the flow rate sensor 66, and various flow rate sensors such as an impeller-type flow rate sensor may be used.

[0023] The on-off valve 68 is an automatic on-off valve such as a solenoid valve, an electric valve, etc. The on-off valve 68 in this embodiment is provided upstream of the flow rate sensor 66 in the water supply flow path 50.

[0024] The water supply system 10 includes a control unit 86 that controls the operation of the water supply system 10. The control unit 86 is, for example, a microcomputer or the like, and is configured by combining a CPU, a ROM, and a RAM.

[0025] The control unit 86 can control the opening and closing operation of the on-off valve 68. The control unit 86 sets parameters related to a drive voltage or drive current (here, drive voltage) for driving the liquid delivery unit 64, and controls the flow rate of the raw liquid delivered from the liquid delivery unit 64 by supplying the drive voltage or drive current of the set parameters to the liquid delivery unit 64. To achieve this, the control unit 86 of this embodiment sets the duty ratio of the drive voltage generated by PWM (Pulse Width Modulation) control as a parameter related to the drive voltage. Alternatively, the parameter related to the drive voltage may be the voltage value of the drive voltage, etc. When the liquid delivery unit 64 is driven by a drive current, the parameter related to the drive current may be the current value of the drive current, etc.

[0026] The control unit 86 performs constant concentration control, controlling the flow rate of the concentrate based on the detected flow rate of the raw water detected by the flow rate sensor 66, so that the concentration of a specific component (e.g., a specific food additive) of the concentrate in the dilution water reaches a target concentration. In this specification, concentration refers to a mass percent concentration (wt%). This target concentration is set so that it falls within a predetermined target range for the specific component. The upper limit of this target range is set, for example, to avoid excessive intake of the specific component of the concentrate.

[0027] The raw water flow rate to be passed through the confluence 70 where the feedwater flow path 50 and the concentrate flow path 62 join is defined as Q (L / min), and the concentrate flow rate to be passed through the confluence 70 is defined as q (L / min). When a concentrate flow rate q is added to raw water with a raw water flow rate Q at the confluence 70 of the feedwater flow path 50, dilution water with a flow rate (Q+q) passes through the feedwater flow path 50 downstream of the confluence 70. The concentration of a specific component in this concentrate is defined as A0 (wt%), and the target concentration of the specific component in the dilution water is defined as A1 (wt%). In this case, the following equation (1) holds: (Q+q)×A1=q×A0 (1)

[0028] Using this equation (1), the following relational equation (2) can be derived. q={A1 / (A0-A1)}×Q (2)

[0029] As can be seen from this relational expression (2), when raw water is flowing at a raw water flow rate Q, the concentration of a specific component in dilution water can be adjusted to the target concentration A1 by sending the raw water from the liquid sending unit 64 at a raw water flow rate q determined from relational expression (2) according to the raw water flow rate Q, concentration A0, and target concentration A1. Hereinafter, the raw water flow rate q corresponding to the raw water flow rate Q for adjusting the specific component to the target concentration A1 in the dilution water will be referred to as the target raw water flow rate qt. This target raw water flow rate qt is a value determined according to the raw water flow rate Q, concentrations A0, and A1 from relational expression (2) which shows the relationship between the target raw water flow rate qt and the raw water flow rate Q for adjusting the target concentration A1.

[0030] When performing constant concentration control, the control unit 86 acquires the detected value of the raw water flow rate Q detected by the flow rate sensor 66. Thereafter, the control unit 86 derives parameters related to the required drive voltage or required drive current to be supplied to the liquid delivery unit 64 in order to deliver the target raw water flow rate qt based on the detected value of the raw water flow rate Q. There is a correlation between the parameters related to the required drive voltage or required drive current to deliver the target raw water flow rate qt and the raw water flow rate Q. When deriving the parameters related to the required drive voltage or required drive current to be supplied to the liquid delivery unit 64, relationship information indicating this correlation may be stored in advance in the storage unit 88, and the detected value of the raw water flow rate Q may be input into the relationship information.

[0031] This relationship information is specified, for example, by an equation, table, or the like, which takes the raw water flow rate Q as input and outputs parameters related to the required drive voltage or drive current for delivering the target raw water flow rate qt. This relationship information is determined according to the concentrations A0 and A1 of the raw water and dilution water. In an operating environment where these concentrations A0 and A1 are fixed, an equation, or the like, specified by the relationship information can be used without considering the concentrations A0 and A1. On the other hand, if the concentration A0 varies depending on the type of raw water, or if the concentration A1 of the dilution water can be changed based on user preference, it is necessary to consider the differences in the concentrations A0 and A1. To address this, the relationship information may be specified by an equation, or the like, which takes the concentrations A0 and A1 of the raw water and dilution water set by the user via an input unit (not shown) and the raw water flow rate Q detected by the flow sensor 66 as inputs and outputs parameters related to the required drive voltage or drive current. Alternatively, multiple pieces of relationship information corresponding to different combinations of the concentrations A0 and A1 of the raw water and dilution water may be stored in advance, and relationship information such as an equation corresponding to the concentrations A0 and A1 actually used may be used.

[0032] The control unit 86 supplies the required drive voltage or required drive current of the derived parameter to the solution delivery unit 64, thereby controlling the flow rate of the solution delivery unit 64 to the target flow rate qt of the solution. This allows the flow rate of the solution delivery unit 64 to be controlled to the target flow rate qt for adjusting the specific component in the dilution water to the target concentration A1, depending on the detected value of the raw water flow rate Q, thereby enabling the concentration of the specific component in the dilution water to be the target concentration A1. The control unit 86 controls the flow rate of the solution delivery unit 64 based on the detected value of the raw water flow rate Q so that the concentration of the specific component in the dilution water is the target concentration A1. At this time, the control unit 86 controls the solution delivery unit 64 so that the flow rate of the solution increases as the detected value of the raw water flow rate Q increases.

[0033] The effects of the water supply system 10 described above will be explained.

[0034] The water supply system 10 includes a control unit 86 that controls the raw water flow rate of the liquid supply unit 64 based on the detected raw water flow rate so that the concentration of a specific component in the dilution water reaches a target concentration. Therefore, even if the raw water flow rate in the feedwater flow path 50 fluctuates, the raw water flow rate can be controlled in accordance with the raw water flow rate to bring the concentration of the specific component in the dilution water closer to the target concentration. Consequently, even if the raw water flow rate fluctuates, it becomes possible to suppress variations in the concentration of the specific component in the dilution water. Such variations in raw water flow rate occur, for example, due to variations in the water supply pressure of the water supply source 20 between regions, variations in the components of the water supply system 10 (open / close valve 68, piping, etc.), etc. In addition, variations in raw water flow rate can also occur, for example, when water is simultaneously supplied to multiple feedwater paths from a common water supply source 20.

[0035] Furthermore, in the case of a drink server installed in a commercial facility, etc., diluted water of a target concentration is generated by supplying a specified amount of raw water and concentrate into a container to which the water is supplied by the water supply system 10. Therefore, in order to generate diluted water of a target concentration, it is necessary to wait until the specified amount of raw water and concentrate has been supplied, and the user cannot freely switch whether or not to supply water during this water supply. In this regard, according to this embodiment, diluted water is generated to achieve the target concentration within the water supply flow path 50. Therefore, the user can freely switch whether or not to supply water to the water supply destination (water-receiving portion 12) by the water supply system 10, and diluted water of a target concentration can be stably supplied to the water-receiving portion 12.

[0036] This concentration variation becomes more pronounced as the dilution ratio, which is the ratio of the raw solution flow rate to the raw water flow rate, decreases. In the water supply system 10 of this embodiment, the raw solution is diluted with raw water so that the dilution ratio is 1000 times or more. Even in such cases, there is an advantage in that diluted water can be supplied in which the concentration variation of specific components is suppressed.

[0037] Next, other features of the water supply system 10 will be described.

[0038] The control unit 86 can operate in accordance with user operation of the water supply operating unit 90. The water supply operating unit 90 is operated by the user to switch between supplying water to the water-receiving unit 12 and not supplying water to the water-receiving unit 12. Specific examples of the water supply operating unit 90 are not particularly limited, and may be constituted by a mechanical component such as a rotary handle provided on a water discharge device such as this embodiment, or an information processing terminal (smartphone, tablet, etc.). The water supply operating unit 90 can select one of multiple instructions in accordance with user operation, and outputs the selected instruction to the control unit 86. The instructions selectable by the water supply operating unit 90 include a water supply instruction to supply water to the water-receiving unit 12 and a water stop instruction to stop the water supply to the water-receiving unit 12.

[0039] Please refer to Figure 2. The top row of Figure 2 indicates whether the instruction output from the water supply operating unit 90 to the control unit 86 is a water supply instruction or a water stop instruction. The second row from the top of Figure 2 indicates the open / closed state of the on-off valve 68. The second row from the bottom of Figure 2 indicates the magnitude of the drive voltage or drive current output from the control unit 86 to the liquid delivery unit 64. The bottom row of Figure 2 indicates whether the raw water flow rate is detected by the flow rate sensor 66.

[0040] FIG. 2 shows an example in which the control unit 86 receives a water supply instruction from the water supply operating unit 90 at time t1, and receives a water stop instruction from the water supply operating unit 90 at time t5.

[0041] When the control unit 86 receives the water supply instruction, it opens the on-off valve 68 and starts the supply of the concentrate by the liquid supply unit 64. This causes the concentrate to be added from the concentrate flow path 62 to the water supply flow path 50. As a result, dilution water is produced in the water supply flow path 50, and the supply of the dilution water from the water supply flow path 50 to the water-receiving portion 12 begins.

[0042] When the control unit 86 receives the water stop command, it closes the on-off valve 68 and stops the liquid supply by the liquid supply unit 64. This stops the flow of raw water through the water supply flow path 50 and stops the addition of raw liquid from the raw liquid flow path 62 to the water supply flow path 50. As a result, the supply of dilution water from the water supply flow path 50 to the water-receiving unit 12 is stopped. In this way, the control unit 86 can switch between supplying dilution water to the water-receiving unit 12 and not supplying it by controlling the on-off valve 68 and the liquid supply unit 64 in accordance with the user's operation of the water supply operating unit 90.

[0043] Here, when starting the supply of dilution water from the water supply flow path 50 to the water-receiving portion 12, the control unit 86 of this embodiment first opens the on-off valve 68, and then starts the supply of the concentrate solution by the liquid supply unit 64 when predetermined liquid supply start conditions (described later) are satisfied (see times t1 and t3). In other words, the timing for opening the on-off valve 68 precedes the timing for starting liquid supply by the liquid supply unit 64. Here, opening the on-off valve 68 means starting to output a valve open signal for opening the on-off valve 68 from the control unit 86 to the on-off valve 68. Furthermore, starting liquid supply by the liquid supply unit 64 means starting to supply a drive voltage or drive current from the control unit 86 to the liquid supply unit 64. The reason for this will be explained.

[0044] A high internal pressure acts on the downstream flow path portion of the concentrate flow path 62 downstream of the liquid supply unit 64 due to the pressurized concentrate flowing from the liquid supply unit 64 while the dilution water is being supplied to the water-receiving portion 12. Therefore, after the supply of dilution water to the water-receiving portion 12 is stopped, concentrate under high internal pressure tends to remain in the downstream flow path portion of the concentrate flow path 62. This is particularly likely to occur when the on-off valve 68 closes before the liquid supply unit 64 stops supplying the concentrate, as described below. If the concentrate remaining in the concentrate flow path 62 diffuses into the stationary raw water in the water supply flow path 50, diluted water with a high concentration of a specific component will be generated near the confluence 70 of the water supply flow path 50. Consider a case where the liquid supply unit 64 starts supplying the concentrate before the on-off valve 68 opens. In this case, before the highly concentrated diluted water remaining at the confluence 70 of the water supply flow path 50 begins to flow, the concentrate begins to be added to the diluted water remaining at the confluence 70 from the concentrate flow path 62, which may result in the diluted water becoming even more concentrated.

[0045] This problem is more likely to occur, for example, as the flow path length from the upstream end of the water supply flow path 50 to the junction 70 becomes longer than the flow path length from the liquid supply section 64 of the concentrate flow path 62 to the junction 70. Furthermore, this problem is more likely to occur as the pressure loss caused by components (such as the reforming cartridge 52, the switching valve 56, and the fourth check valve 72) located between the upstream end of the water supply flow path 50 and the junction 70 increases. If this problem occurs, dilution water containing a specific component at a concentration excessively higher than the target concentration may be transiently supplied to the water-receiving section 12. The addition of concentrate to raw water is performed to provide diluted water with added value, such as flavor or aroma. If the concentration of a specific component in the diluted water becomes excessively high, the diluted water will not be able to achieve the value specified, and this is desirably avoided.

[0046] As a countermeasure for this, the control unit 86 of this embodiment opens the on-off valve 68 before starting the liquid delivery by the liquid delivery unit 64. This makes it easier to start adding the concentrate from the concentrate flow path 62 to the raw water flowing through the junction 70 after the highly concentrated dilution water remaining at the junction 70 of the water supply flow path 50 has started to flow. Consequently, when starting the supply of dilution water to the water-receiving portion 12, it becomes difficult to add the concentrate to the dilution water remaining at the junction 70 of the water supply flow path 50, making it easier to avoid a situation in which dilution water having an excessively high concentration of a specific component is transiently supplied to the water-receiving portion 12.

[0047] As described below, consider a case in which the on-off valve 68 is closed after a set time Δtb has elapsed since the liquid delivery unit 64 stopped delivering the liquid to prevent a specific component from becoming highly concentrated in the dilution water. In this case, the longer the set time Δtb, the longer the waiting time until the water delivery to the water-receiving unit 12 is stopped, which may lead to the user perceiving poor response when the water delivery is stopped. For this reason, there is a limit to how long the set time Δtb can be extended. In this regard, if the on-off valve 68 is opened first and then the liquid delivery unit 64 starts delivering the liquid after a set time Δta has elapsed, extending the set time Δta does not result in a situation in which the waiting time until the water delivery is stopped becomes long. Therefore, there is also the advantage that the set time Δta can be easily extended to prevent a specific component from becoming highly concentrated in the dilution water.

[0048] The liquid transfer start condition in this embodiment is that the flow sensor 66 continues to detect the flow of raw water in the water supply passage 50 for a predetermined set time Δta after the flow sensor 66 begins to detect the flow of raw water. In the example of FIG. 2 , this means that the flow sensor 66 continues to detect the flow of raw water from time t2 when the flow sensor 66 begins to detect the flow of raw water until the set time Δta has elapsed. Under this liquid transfer start condition, if the flow sensor 66 continues to detect that no raw water is flowing in the water supply passage 50, even after the on-off valve 68 is opened, the liquid transfer unit 64 will not start transferring the raw water. The same applies if the flow sensor 66 detects that no raw water is flowing within the set time Δta after the flow sensor 66 begins to detect the flow of raw water. Alternatively, the liquid transfer start condition may simply be that the set time Δta has elapsed since the flow sensor 66 began to detect the flow of raw water. Alternatively, the liquid transfer start condition may be the lapse of a predetermined set time Δta′ (see FIG. 2) from the opening of the on-off valve 68, regardless of the detection result of the flow rate sensor 66. When either of the liquid transfer start conditions is met, the control unit 86 consequently opens the on-off valve 68 first, and then starts transferring the stock solution by the liquid transfer unit 64.

[0049] It is preferable that these set times Δta and Δta' be set to times that are not excessively long (for example, Δta is 0.9 seconds and Δta' is 1.0 seconds) while ensuring the time necessary for the highly concentrated diluted water to begin flowing at the confluence 70 of the water supply flow path 50 as described above.

[0050] When stopping the supply of dilution water to the water-receiving portion 12, the control unit 86 of this embodiment first stops the liquid delivery by the liquid delivery unit 64, and then closes the on-off valve 68 after a predetermined set time Δtb has elapsed. In other words, the timing for stopping the liquid delivery by the liquid delivery unit 64 precedes the timing for closing the on-off valve 68. This corresponds to stopping the liquid delivery by stopping the supply of drive voltage to the liquid delivery unit 64 at time t5 and closing the on-off valve 68 at time t6 in the example of FIG. 2. Here, stopping the liquid delivery by the liquid delivery unit 64 means starting to stop the supply of drive voltage or drive current from the control unit 86 to the liquid delivery unit 64. Here, closing the on-off valve 68 means starting to output a valve close signal from the control unit 86 to the on-off valve 68 to close the on-off valve 68. The reason for this will be explained.

[0051] Consider a case where the timing of closing the on-off valve 68 occurs before the timing of stopping the liquid supply by the liquid supply unit 64. In this case, as described above, after the liquid supply by the liquid supply unit 64 is stopped, the raw liquid under high internal pressure remaining in the raw liquid flow path 62 diffuses into the stationary raw water at the junction 70 of the water supply flow path 50, making it easier for diluted water with a high concentration of a specific component to be produced near the junction 70 of the water supply flow path 50. If this problem occurs, when the supply of dilution water from the water supply flow path 50 to the water-receiving unit 12 begins, a situation may occur in which diluted water with an excessively high concentration of the specific component is transiently supplied to the water-receiving unit 12.

[0052] As a countermeasure for this, the control unit 86 of this embodiment stops the liquid delivery by the liquid delivery unit 64 and then closes the on-off valve 68. Therefore, the on-off valve 68 can be closed after the high internal pressure raw liquid remaining in the downstream flow path of the raw liquid flow path 62 is released into the raw water that continues to flow through the water supply flow path 50. This in turn makes it difficult for the high internal pressure raw liquid remaining in the raw liquid flow path 62 to diffuse into the stationary raw water at the junction 70 of the water supply flow path 50, making it easier to avoid a situation in which diluted water having an excessively high concentration of a specific component is transiently supplied to the water-receiving portion 12.

[0053] From this perspective, it is preferable to set the set time Δtb to a time that is not excessively long (e.g., 0.5 seconds) while ensuring the time necessary to release the high internal pressure raw liquid remaining in the downstream flow path section of the raw liquid flow path 62 into the water supply flow path 50.

[0054] When starting liquid delivery by the liquid delivery unit 64, the control unit 86 controls the raw liquid flow rate of the liquid delivery unit 64 so that the target raw liquid flow rate qt is reached after the raw liquid flow rate reaches an initial raw liquid flow rate qs that is greater than the target raw liquid flow rate qt according to the detected raw water flow rate. In controlling the raw liquid flow rate of the liquid delivery unit 64 so that the initial raw liquid flow rate qs is greater than the target raw liquid flow rate qt, the control unit 86 first derives a first parameter related to the required drive voltage or required drive current according to the detected raw water flow rate for delivering the target raw liquid flow rate qt. Here, an example is shown in which a first duty ratio that obtains a first voltage value V1 is derived as the first parameter related to the required drive voltage.

[0055] Next, a second parameter related to the starting drive voltage or starting drive current for delivering the initial stock solution flow rate qs is derived based on the derived first parameter related to the drive voltage or drive current required to deliver the target stock solution flow rate qt. Here, an example is shown in which a second duty ratio is derived as the second parameter related to the starting drive voltage, which provides a second voltage value V2 higher than the first voltage value V1. This starting stock solution flow rate qs is set so that the ratio of the starting stock solution flow rate qs to the target stock solution flow rate qt is equal to or greater than a predetermined ratio (e.g., 1.2 times). In this embodiment, there is a linear relationship between the voltage value of the drive voltage and the stock solution flow rate when the drive voltage is supplied. Therefore, it can be said that the voltage value V2 of the starting drive voltage is set so that the ratio of the voltage value V2 to the voltage value V1 of the target drive voltage is equal to or greater than a predetermined ratio (e.g., 1.2 times). If the ratio of the initial concentrate flow rate qs to the target concentrate flow rate qt exceeds the upper limit of the range in which the flow rate can be adjusted by the liquid delivery unit 64, the initial concentrate flow rate qs is set to that upper limit.

[0056] Thereafter, the control unit 86 controls the concentrate flow rate of the solution delivery unit 64 to achieve the initial concentrate flow rate qs by supplying the solution delivery unit 64 with the starting drive voltage or starting drive current of the derived second parameter. After the set time Δtc has elapsed since the start of supply of the starting drive voltage or starting drive current, the control unit 86 supplies the solution delivery unit 64 with the required drive voltage or required drive current of the derived first parameter. This corresponds to the example of FIG. 2 , where a starting drive voltage with a voltage value V2 (second duty ratio) is supplied to the solution delivery unit 64 at time t3, and then a target drive voltage with a voltage value V1 (first duty ratio) is supplied to the solution delivery unit 64 at time t4. The control unit 86 controls the solution delivery unit 64 to achieve the initial concentrate flow rate qs until the set time Δtc has elapsed, and then controls the solution delivery unit 64 to achieve the target concentrate flow rate qt after the set time Δtc has elapsed. After the set time Δtc has elapsed, the control unit 86 performs the above-mentioned constant concentration control, controlling the liquid delivery unit 64 to achieve the target raw solution flow rate qt based on the raw water flow rate detected by the flow rate sensor 66. The control unit 86 performs constant concentration control until the liquid delivery by the liquid delivery unit 64 is stopped. In the example of Figure 2, constant concentration control is performed from time t4 to time t5. The reason for controlling the raw solution flow rate to reach the target raw solution flow rate qt after reaching the initial raw solution flow rate qs will be explained below.

[0057] Depending on the structure of the liquid delivery unit 64, a liquid delivery delay may occur between the start of supplying the required drive voltage or drive current corresponding to the target concentrate flow rate qt to the liquid delivery unit 64 and the time when the concentrate flow rate actually delivered from the liquid delivery unit 64 reaches the target concentrate flow rate qt. This liquid delivery delay may be caused, for example, by a delay in starting the motor of the liquid delivery unit 64 or a delay in increasing the discharge pressure of the pump of the liquid delivery unit 64. If this liquid delivery delay occurs, the concentrate at the target concentrate flow rate qt cannot be added to the raw water in the water supply flow path 50. This may result in a transient decrease in concentration of the dilution water delivered from the water receiving unit 12, where the concentration is lower than the target concentration until the target concentrate flow rate qt is reached. As described above, consider a case in which dilution water with a high concentration of a specific component is produced near the confluence 70 of the water supply flow path 50 when the supply of dilution water to the water receiving unit 12 is stopped. In this case, after the highly concentrated diluted water is supplied to the water-receiving portion 12, the diluted water with the reduced concentration described here is transiently supplied to the water-receiving portion 12.

[0058] Therefore, in this embodiment, when starting the liquid delivery by the liquid delivery unit 64, the control unit 86 controls the liquid delivery unit 64 to set the initial raw liquid flow rate qs, which is greater than the target raw liquid flow rate qt, before setting the target raw liquid flow rate qt according to the detected raw water flow rate. Therefore, immediately after dilution water whose concentration is lower than the target concentration due to a liquid delivery delay is delivered to the water-receiving unit 12, dilution water whose concentration is higher than the target concentration can be temporarily delivered to the water-receiving unit 12. This allows the dilution water whose concentration is higher than the target concentration to be merged with the dilution water whose concentration is lower than the target concentration delivered earlier at the destination of the dilution water, thereby compensating for the shortage of the specific component due to the reduction in concentration from the target concentration. Ultimately, even if there is a liquid delivery delay, the destination of the dilution water can obtain dilution water whose specific component has a concentration as close as possible to the target concentration. Note that, when the water-receiving unit 12 is a water-discharging device, the destination of the dilution water refers to a container or the like that receives the dilution water discharged from the water-discharging device.

[0059] From this perspective, the set time Δtc should be set to a time (e.g., 1.0 second) that is not excessively long while ensuring the time required to make up for the shortage of a specific component that occurs when dilution water whose concentration is lower than the target concentration due to a liquid delivery delay is supplied. The ratio of the starting concentrate flow rate qs to the target concentrate flow rate qt should also be set to a ratio that ensures the concentrate flow rate required to make up for the shortage of a similar specific component while not making the concentrate flow rate excessively large.

[0060] When the sixth check valve 80 is provided in the concentrate flow path 62, using the initial concentrate flow rate qs also has the following advantage. The concentrate flow path 62 includes an intermediate flow path section provided between the sixth check valve 80 and the liquid delivery section 64. When the liquid delivery section 64 starts delivering the concentrate, the internal pressure of the concentrate in the intermediate flow path section of the concentrate flow path 62 gradually increases. This increase in the internal pressure of the concentrate causes a part of the sixth check valve 80 (such as a valve element) to move against the internal pressure of the raw water downstream of the sixth check valve 80, thereby changing from a closed state to an open state. Here, by delivering the initial concentrate flow rate qs, which is greater than the target concentrate flow rate qt, to the intermediate flow path section of the concentrate flow path 62, the internal pressure of the concentrate in that intermediate flow path section can be increased more quickly, allowing the sixth check valve 80 to transition from a closed state to an open state more quickly. Furthermore, the control unit 86 controls the liquid supply unit 64 so that the target concentrate flow rate qt is reached after the initial concentrate flow rate qs is reached. Therefore, the liquid supply unit 64 is controlled so that the target concentrate flow rate qt is reached after the valve is opened early, so that dilution water of the target concentration can be produced early.

[0061] In this embodiment, the modifying cartridge 52, the switching valve 56, the liquid source 60, the liquid delivery section 64, etc. are integrated as an addition unit 92. These do not have to be integrated.

[0062] Next, variations of the components described above will be described.

[0063] The water supply system 10 does not need to include the second water supply line 18. In this case, raw water such as tap water may be supplied from the water supply source 20 to the water supply passage 50 of the first water supply line 16.

[0064] When starting the supply of dilution water from the water supply flow path 50 to the water-receiving portion 12, the control portion 86 may open the on-off valve 68 at the same time as starting the liquid supply by the liquid supply portion 64. This will set the above-mentioned set time Δta' to zero. Alternatively, in this case, the control portion 86 may first start the liquid supply by the liquid supply portion 64 and then open the on-off valve 68.

[0065] When stopping the supply of dilution water from the water supply passage 50 to the water-receiving portion 12, the control portion 86 may close the on-off valve 68 at the same time as stopping the supply of the water by the liquid supply portion 64. This will set the aforementioned set time Δtb to zero. Alternatively, in this case, the control portion 86 may close the on-off valve 68 first, and then stop the supply of the water by the liquid supply portion 64.

[0066] When starting the liquid delivery by the liquid delivery unit 64, the control unit 86 may control the liquid delivery unit 64 so that the target raw liquid flow rate qt is achieved, rather than setting the initial raw liquid flow rate qs to a value greater than the target raw liquid flow rate qt determined based on the detected raw water flow rate. This results in the aforementioned set time Δtc being set to zero. Regardless of whether or not control is performed to achieve the initial raw liquid flow rate qs, the sixth check valve 80 may not be required.

[0067] At least one of the above-mentioned Δta (or Δta'), Δtb, and Δtc may be set to zero.

[0068] The above-described embodiments and variations are merely examples. The abstract technical ideas should not be interpreted as being limited to the contents of the embodiments and variations. Many design changes are possible in the contents of the embodiments and variations, such as changing, adding, or deleting components. In the above-described embodiments, the contents that allow such design changes are emphasized by adding the notation "embodiment." However, design changes are naturally permitted even in contents that do not have such notation.

[0069] When the technical ideas embodied in the above-described embodiments and modified forms are generalized, it can be said that the technical ideas described in the following items are included.

[0070] The first item is a water supply system comprising: a water supply flow path through which raw water flows; a raw liquid flow path that adds raw liquid supplied from a liquid source to the raw water flowing through the water supply flow path; a liquid delivery unit provided in the raw liquid flow path that delivers the raw liquid to the water supply flow path; a flow sensor provided in the water supply flow path; and a control unit that controls the flow rate of the raw liquid delivered from the liquid delivery unit based on a detection value indicating the raw water flow rate detected by the flow sensor so that the concentration of a specific component of the raw liquid in diluted water produced by adding the raw liquid to the raw water becomes a target concentration.

[0071] The second item is a water supply system described in the first item, which is provided with an on-off valve provided in the water supply flow path, and when the control unit starts supplying the diluted water from the water supply flow path to the water-receiving part, it opens the on-off valve and then starts supplying the water by the liquid supply unit.

[0072] The third item is a water supply system described in either the first or second item, which is provided with an on-off valve provided in the water supply flow path, and when the control unit stops the supply of the dilution water from the water supply flow path to the water-receiving part, it stops the liquid supply by the liquid supply unit and then closes the on-off valve.

[0073] The fourth item is a water supply system described in any of the first to third items, in which when the raw solution flow rate corresponding to the raw water flow rate for bringing the specific component to the target concentration in the dilution water is called the target raw solution flow rate, the control unit controls the liquid delivery unit so that when starting liquid delivery by the liquid delivery unit, the target raw solution flow rate is reached after the initial raw solution flow rate becomes higher than the target raw solution flow rate corresponding to the detected value of the raw water flow rate.

[0074] A fifth item is the water supply system according to the fourth item, further comprising a check valve provided on the raw liquid flow path downstream of the liquid delivery section to prevent backflow to the upstream side.

[0075] The sixth item is a water supply system described in any one of the first to fifth items, in which when the raw solution flow rate for bringing the specific component to the target concentration in the dilution water is referred to as the target raw solution flow rate, the control unit derives parameters related to the required drive voltage or required drive current to be supplied to the liquid delivery unit in order to deliver the liquid at the target raw solution flow rate based on the detected value of the raw water flow rate, and controls the raw solution flow rate of the liquid delivery unit to become the target raw solution flow rate by supplying the required drive voltage or required drive current of the derived parameters to the liquid delivery unit.

[0076] The seventh item is a water supply system described in the sixth item, which includes a memory unit that stores relationship information showing the relationship between parameters related to the required drive voltage or required drive current to be supplied to the liquid delivery unit in order to deliver liquid at the target raw liquid flow rate and the raw water flow rate, and the control unit uses the relationship information stored in the memory unit to derive parameters related to the required drive voltage or required drive current from the detected value of the raw water flow rate. [Explanation of symbols]

[0077] 10...water supply system, 12...water receiving portion, 28...raw liquid flow path, 50...water supply flow path, 62...raw liquid flow path, 64...liquid delivery portion, 66...flow rate sensor, 68...on-off valve, 80...check valve, 86...control portion, 88...memory portion.

Claims

1. a water supply channel through which raw water flows; a raw liquid flow path for adding raw liquid supplied from a liquid source to raw water flowing through the water supply flow path; a liquid delivery section provided in the raw liquid flow path and delivering the raw liquid to the water supply flow path; a flow rate sensor provided in the water supply flow path; a control unit that controls the flow rate of the raw solution sent from the liquid sending unit based on a detection value indicating the raw water flow rate detected by the flow sensor so that the concentration of a specific component of the raw solution in dilution water generated by adding the raw solution to the raw water becomes a target concentration; an on-off valve provided in the water supply flow path, When starting the supply of the dilution water from the water supply flow path to the water-received portion, the control unit opens the on-off valve to allow the dilution water remaining at the confluence of the water supply flow path and the concentrate flow path to begin flowing, and then starts adding the concentrate from the concentrate flow path to the raw water flowing through the confluence, When the flow rate of the concentrate for adjusting the specific component to the target concentration in the dilution water is referred to as a target flow rate of the concentrate, The control unit derives parameters related to the required drive voltage or required drive current to be supplied to the liquid delivery unit in order to deliver the liquid at the target raw liquid flow rate based on the detected value of the raw water flow rate, and controls the raw liquid flow rate of the liquid delivery unit to become the target raw liquid flow rate by continuously supplying the required drive voltage or required drive current of the derived parameters to the liquid delivery unit.

2. 2. The water supply system according to claim 1, wherein pressurized concentrate is supplied from the liquid supply section to the confluence section while the dilution water is being supplied to the water-receiving section.

3. The water supply system according to claim 1 , wherein when the control unit stops the supply of the dilution water from the water supply flow path to the water-receiving part, the control unit stops the liquid supply by the liquid supply unit and then closes the on-off valve.

4. A water supply system as described in Claim 1, wherein when starting liquid delivery by the liquid delivery unit, the control unit controls the liquid delivery unit so that the starting liquid delivery flow rate becomes greater than the target liquid delivery flow rate corresponding to the detected value of the raw water flow rate, and then becomes the target liquid delivery flow rate.

5. The water supply system according to claim 4, further comprising a check valve provided on the raw liquid flow path downstream of the liquid delivery section to prevent backflow toward the upstream side.

6. a storage unit for storing relationship information indicating a relationship between a parameter related to a required drive voltage or a required drive current to be supplied to the liquid delivery unit in order to deliver the liquid at the target raw water flow rate and the raw water flow rate; The water supply system according to claim 1 , wherein the control unit derives parameters relating to a required drive voltage or a required drive current from the detected value of the raw water flow rate using the relationship information stored in the memory unit.

7. A water supply operation unit is provided which can switch on and off the supply of water to the water-receiving portion, The water supply system according to claim 1 , wherein the control unit, when receiving a water supply instruction via the water supply operating unit, opens the on-off valve and starts the liquid supply unit to supply the undiluted liquid.

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