Water softening device and mist spraying apparatus equipped with water softening device

Abstract

A water softening device (1) comprises: a housing (3) having an internal space; an inflow port (2) through which a treatment target water flows into the internal space; a water treatment layer (4) that removes hardness components from the treatment target water and generates a weakly acidic soft water; and an outflow port (5) through which the weakly acidic soft water flows out from the internal space. The water treatment layer (4) comprises: a first soft water layer (4a) that removes the hardness components from the treatment target water; a neutralization layer (4b) that is provided downstream of the first soft water layer (4a) and neutralizes the treatment target water; a second soft water layer (4c) that is provided downstream of the neutralization layer (4b) and removes the hardness components from the treatment target water; and an acidification layer (4d) that is provided downstream of the second soft water layer (4c), acidifies the treatment target water, and removes the hardness components from the treatment target water.

Description

Water softening device and mist spraying device equipped with water softening device

[0001] The present disclosure relates to a water softening device and a mist spraying device equipped with a water softening device.

[0002] Many water softeners using cation exchange resins have been proposed. For example, as shown in Patent Document 1, a system is known in which a weakly acidic cation exchange resin is used to exchange calcium ions or magnesium ions, which are hardness components contained in raw water, for hydrogen ions to obtain soft water.

[0003] JP 2016-163890 A

[0004] In conventional water softeners using such weakly acidic cation exchange resins, the ion exchange rate of the weakly acidic cation exchange resin is slower than that of the strongly acidic cation exchange resin. Therefore, when it is necessary to downsize the water softener, for example, to use a soft water cartridge, there is a concern that the amount of ion exchange resin that can be loaded is small and the hardness in the raw water may not be sufficiently removed.

[0005] An object of the present disclosure is to provide a water softening device that can be made smaller while maintaining or improving water softening performance.

[0006] The water softening device according to the present disclosure includes a housing having an internal space, an inlet for introducing water to be treated into the internal space, a water treatment layer disposed in the internal space for removing hardness components from the water to be treated and producing weakly acidic soft water, and an outlet for discharging the weakly acidic soft water from the internal space. The water treatment layer includes a first soft water layer for removing hardness components from the water to be treated using a weakly acidic cation exchange resin, a neutralization layer disposed downstream of the first soft water layer for neutralizing the water to be treated using a weakly basic anion exchange resin, a second soft water layer disposed downstream of the neutralization layer for removing hardness components from the water to be treated using a weakly acidic cation exchange resin, and an acidification layer disposed downstream of the second soft water layer for acidifying the water to be treated and removing hardness components from the water to be treated using an H-type strongly acidic cation exchange resin.

[0007] According to the present disclosure, it is possible to provide a water softening device that is miniaturized while maintaining or improving water softening performance.

[0008] Fig. 1 is a conceptual diagram showing the configuration of a water softening device with a water treatment layer attached to a housing. Fig. 2 is a conceptual diagram showing the configuration of a water softening device with a part of the water treatment layer removed from the housing. Fig. 3 is a schematic diagram showing an example of an installed state of a mist spraying device. Fig. 4 is a conceptual diagram showing the configuration of a mist spraying device according to a second embodiment of the present disclosure. Fig. 5 is a structural diagram showing a flow path of a mist spraying device according to the second embodiment of the present disclosure.

[0009] The water softening device according to the present disclosure includes a water treatment layer that produces weakly acidic soft water. The water treatment layer includes a first soft water layer, a neutralization layer, a second soft water layer, and an acidification layer. The first and second soft water layers soften water by removing hardness components from the water. The neutralization layer neutralizes the soft water that has passed through the first soft water layer. The acidification layer acidifies the soft water that has flowed in from the second soft water layer and removes hardness components. The water softening device is configured so that water to be treated, such as city water, flows through the first soft water layer, neutralization layer, second soft water layer, and acidification layer in this order. The water to be treated (city water) can be tap water, well water, or the like.

[0010] According to this configuration, water to be treated containing hardness components is softened in the first soft water layer by adsorption of the hardness components onto the cation exchange resin. Meanwhile, cations (hydrogen ions) released from the cation exchange resin are released into the water to be treated that flows into the first soft water layer. The first soft water that flows out of the first soft water layer then flows into the neutralization layer, where the hydrogen ions contained in the soft water are removed by the weakly basic ion exchange resin, resulting in neutralization. The neutralized soft water then flows into the second soft water layer and is softened by the same process as in the first soft water layer. In other words, by sandwiching the neutralization layer between the soft water layers, the hydrogen ion concentration in the water can be reduced in the neutralization layer. This facilitates ion exchange between the hardness components and the hydrogen ions held by the weakly acidic cation exchange resin in the second soft water layer. In other words, the reduced hydrogen ion concentration in the water to be treated that flows into the second soft water layer facilitates the release of hydrogen ions from the weakly acidic cation exchange resin in the second soft water layer. As a result, it is possible to maintain or improve the water softening performance.

[0011] Furthermore, the second softened water that has passed through the second softened water layer flows through an acidification layer filled with an H-type strongly acidic cation exchange resin. This allows the H-type strongly acidic cation exchange resin to remove hardness components and cations other than hardness components, such as sodium ions, that were not completely removed by the softening in the first and second softened water layers, and release hydrogen ions. Therefore, even when downsizing the water softener, the water softening performance can be compensated for by using an H-type strongly acidic cation exchange resin, which has a faster exchange rate than a weakly acidic cation exchange resin. This allows the water softener to be downsized while maintaining or improving its water softening performance per unit volume.

[0012] In addition, each of the soft water layer, neutralization layer, and acidification layer may be provided with a cylindrical container whose water inlet opening (upstream opening) and outlet opening (downstream opening) are covered with a water-permeable membrane, and each layer may be detachable from the water softening device.

[0013] With this configuration, the size of the softening layer, neutralization layer, and acidification layer, i.e., the resin filling amount or packing density, can be easily changed using a cylindrical container filled with a fixed amount of ion exchange resin as a unit. Therefore, by changing the softening layer, neutralization layer, and acidification layer depending on the concentrations of hardness components and bicarbonate ions in the water to be treated, it is easy to adjust the hardness and pH of the extracted weakly acidic soft water to the desired values. In other words, it is easy to adjust the water softening performance to suit the water quality of each country or region. This means that there is no need to separately design and manufacture water softeners tailored to the water quality of each country or region, thereby streamlining development and manufacturing costs.

[0014] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. Each of the following embodiments illustrates an example of the present disclosure. The numerical values, shapes, materials, components, and positional relationships of the components shown in each embodiment are merely examples and do not limit the scope of the claims. Furthermore, terms indicating relationships between elements, such as perpendicular and parallel, do not necessarily indicate the strict meaning but also include a range of substantial equivalence, for example, a difference of a few percent. Furthermore, the figures described in each embodiment are not necessarily strict illustrations. Substantially identical components in each figure are designated by the same reference numerals, and redundant explanations may be omitted or simplified.

[0015] (Embodiment 1) A water softening device 1 according to embodiment 1 of the present disclosure will be described with reference to Figures 1 and 2. Figure 1 is a conceptual diagram showing the configuration of the water softening device 1 with a water treatment layer attached to a housing. Figure 2 is a conceptual diagram showing the configuration of the water softening device 1 with some of the water treatment layers removed from the housing.

[0016] (Overall Configuration) The water softening device 1 is a device that produces weakly acidic softened water that can be used as drinking water from city water (raw water containing hardness components) supplied from an external source. Note that the city water, the first softened water 110, the neutralized softened water 120, and the second softened water 130 described below are collectively referred to as the water to be treated.

[0017] The water softening device 1 includes a housing 3 , a protrusion 90 , a water treatment layer 4 , and a protrusion 91 .

[0018] 2 , the housing 3 is a cylindrical structure having an internal space. In other words, the housing 3 is a container for containing the water treatment layer 4. The housing 3 also has a side opening 3b for attaching and detaching the water treatment layer 4 to and from the housing 3.

[0019] The side openings 3b are openings provided on the side of the housing 3. In this embodiment, four side openings 3b are provided lined up along the water flow direction. Each layer of the water treatment layer 4 can be attached to and detached from the housing 3 via the side openings 3b. The side openings 3b are opened by the housing opening / closing part 3a when the water treatment layer 4 is attached or detached, and are closed by the housing opening / closing part 3a when water is flowing. Note that "closed" here refers to a state in which little or no water leaks out from the side openings 3b. On the other hand, "open" refers to a state in which each layer of the water treatment layer 4 can be attached to and detached from the housing 3.

[0020] The housing opening / closing portion 3a is provided on the side of the housing 3 and is a structure having an arc shape in a plan view in the water flow direction. The housing opening / closing portion 3a is provided corresponding to the side opening 3b. In other words, four housing opening / closing portions 3a are provided in a row along the water flow direction. The housing opening / closing portion 3a closes or opens the side opening 3b by rotating around a rotation axis 3c located at the boundary between the housing opening / closing portion 3a and the side opening 3b. More specifically, the housing opening / closing portion 3a closes the side opening 3b by rotating in the direction of the black arrow (a) shown in FIG. 2, and opens the side opening 3b by rotating in the direction of the black arrow (b). Furthermore, the housing opening / closing portion 3a closes the side opening 3b by contacting the periphery of the housing opening / closing portion 3a with the periphery of the side opening 3b. In this case, to prevent water leakage from the contact area, the periphery of the housing opening / closing portion 3a or the periphery of the side opening 3b may be provided with a sealant (not shown).

[0021] The rotation axis 3c is formed by a known technique such as a hinge.

[0022] The protruding portion 90 is a cylindrical structure that protrudes from one surface 101 of the housing 3. The protruding portion 90 is connected to a water pipe that supplies city water. The protruding portion 90 includes an inlet 2.

[0023] The inlet 2 is a circular opening provided on the tip surface of the protruding portion 90 in the protruding direction. City water flows into the inlet 2. In other words, city water flows into the water softening device 1 through the inlet 2. The inlet 2 may be provided on one surface 101 of the housing 3.

[0024] The water treatment layer 4 removes hardness components from city water flowing in through the inlet 2 to produce soft water. More precisely, it produces weakly acidic soft water. Here, weakly acidic soft water means soft water with a pH of, for example, about 4 to 6. The water treatment layer 4 is configured to include, in order along the water flow direction, a first soft water layer 4a, a neutralization layer 4b, a second soft water layer 4c, and an acidification layer 4d.

[0025] The first soft water layer 4a and the second soft water layer 4c are cylindrical and filled with a weakly acidic cation exchange resin 6. There are no particular restrictions on the weakly acidic cation exchange resin 6, and a general-purpose one can be used. Specific examples include those with a carboxyl group (-COOH) as the exchange group. It is desirable that the terminal functional group of the weakly acidic cation exchange resin 6 be a hydrogen ion, in order to acidify the water softened by the weakly acidic cation exchange resin 6.

[0026] In this embodiment, the weakly acidic cation exchange resin 6 filled in the first soft water tank 4a is referred to as the first weakly acidic cation exchange resin 6a, and the weakly acidic cation exchange resin 6 filled in the second soft water tank 4c is referred to as the second weakly acidic cation exchange resin 6b. That is, the first soft water tank 4a is filled with the first weakly acidic cation exchange resin 6a. The second soft water tank 4c is filled with the second weakly acidic cation exchange resin 6b. In the following, the first weakly acidic cation exchange resin 6a and the second weakly acidic cation exchange resin 6b will be referred to as the weakly acidic cation exchange resin 6 unless there is a need to distinguish between them.

[0027] The neutralization layer 4b has a cylindrical shape and is filled with a weakly basic anion exchange resin 7. There are no particular restrictions on the weakly basic anion exchange resin 7, and a general-purpose resin can be used. Specific examples include those in which the functional group is in the free base form. The neutralization layer 4b is provided downstream of the first soft water layer 4a in the water flow direction.

[0028] The second soft water layer 4c is filled with a second weakly acidic cation exchange resin 6b, and is provided downstream of the neutralization layer 4b in the water flow direction.

[0029] The acidification layer 4d is filled with H-type strongly acidic cation exchange resin 8. There are no particular limitations on the H-type strongly acidic cation exchange resin 8, and a general-purpose resin can be used, such as one with a sulfo group (-SO3H) as the exchange group. Hereinafter, unless there is a need to distinguish between the weakly acidic cation exchange resin 6, the weakly basic anion exchange resin 7, and the H-type strongly acidic cation exchange resin 8, they will be collectively referred to as "ion exchange resins." The acidification layer 4d is provided downstream of the second soft water layer 4c in the water flow direction.

[0030] The first soft water layer 4a, the neutralization layer 4b, the second soft water layer 4c, and the acidification layer 4d are partitioned, for example, by identical cylindrical containers (water treatment layer containers 10) whose upstream and downstream openings are covered with water-permeable membranes (water-permeable outer diaphragms 9), and each container is filled with an ion exchange resin. Examples of the water-permeable outer diaphragm 9 include nonwoven fabric and polyester mesh, but there are no particular limitations on the type of membrane as long as it can prevent the ion exchange resin filled inside the water treatment layer container 10 from leaking out of the container.

[0031] The water treatment layer 4 in this embodiment is configured to include a water treatment layer container 10 and a water-permeable outer diaphragm 9 .

[0032] The water treatment vessel 10 is a hollow, generally cylindrical structure provided in each layer of the water treatment layer 4 (i.e., the first soft water layer 4a, the neutralization layer 4b, the second soft water layer 4c, and the acidification layer 4d), and holds an ion exchange resin therein. In this embodiment, four water treatment vessels 10 are provided. Specifically, the water treatment vessels 10 provided as the first soft water layer 4a and the second soft water layer 4c hold a weakly acidic cation exchange resin 6 therein. The water treatment vessel 10 provided as the neutralization layer 4b holds a weakly basic anion exchange resin 7 therein. The water treatment vessel 10 provided as the acidification layer 4d holds an H-type strongly acidic cation exchange resin 8 therein. The water treatment vessels 10 do not necessarily have to be cylindrical and may be, for example, rectangular tubes. Furthermore, in this embodiment, all of the water treatment vessels 10 have the same shape to reduce manufacturing costs and facilitate rearrangement of the layers of the water treatment layer 4. The water treatment vessel 10 is provided with water-permeable outer diaphragms 9 at the upstream and downstream openings in the water flow direction.

[0033] The water-permeable external diaphragms 9 are porous structures provided at the upstream and downstream openings of the water treatment vessel 10. More specifically, they are structures for retaining ion exchange resin within the water treatment vessel 10 and are made of a material that is permeable but prevents the ion exchange resin from leaking out. Specifically, the water-permeable external diaphragms 9 are made of a nonwoven fabric, polyester mesh, or the like. In this embodiment, the water-permeable external diaphragms 9 are provided at two openings (i.e., the upstream opening and the downstream opening) of the water treatment vessel 10, but this is not limited thereto. The water-permeable external diaphragms 9 may be provided so as to cover the ion exchange resin in all directions, for example. In other words, the water-permeable external diaphragm 9 may also serve as the water treatment vessel 10, and the first soft water layer 4a, the neutralization layer 4b, the second soft water layer 4c, and the acidification layer 4d are separated by the water-permeable external diaphragms 9.

[0034] This allows each layer constituting the water treatment layer 4 to be attached and detached one by one from the water softening device 1, and makes it easy to change the size (amount of resin filled) of the first soft water layer 4a, neutralization layer 4b, second soft water layer 4c and acidification layer 4d, with a fixed amount of ion exchange resin filled in each water treatment layer container 10 as one unit.

[0035] Therefore, the sizes (ion exchange resin filling amounts) of the first soft water layer 4a, neutralization layer 4b, second soft water layer 4c, and acidification layer 4d can be adjusted depending on the concentrations of hardness components and other ions contained in city water. This facilitates adjusting the hardness and pH of the extracted weakly acidic soft water to the desired values. For example, when softening city water with a high proportion of hardness components (such as city water in North America), the hardness of the extracted weakly acidic soft water can be efficiently reduced by increasing the filling amount of the first weakly acidic cation exchange resin 6a compared to the filling amount of the second weakly acidic cation exchange resin 6b. In other words, by making each layer of the water treatment layer 4 a cartridge type that can be detached from the housing 3, a water softener tailored to the water quality of each country or region can be realized simply by combining the layers. In other words, there is no need to separately design and manufacture a water softener tailored to the water quality of each country or region, thereby streamlining development and manufacturing costs.

[0036] The protrusion 91 is a cylindrical structure that protrudes from one surface 102 of the housing 3. The protrusion 91 is a structure through which the weakly acidic soft water generated by the water treatment layer 4 flows. The protrusion 91 includes an outlet 5.

[0037] The outlet 5 is a circular opening provided on the tip surface in the protruding direction of the protruding portion 91. The weakly acidic soft water flows out from the outlet 5. In other words, the weakly acidic soft water flows out of the water softening device 1 through the outlet 5. The outlet 5 may be provided on one surface 102 of the housing 3.

[0038] Next, the role of each component of the water softening device 1 will be described with reference to FIGS.

[0039] The first soft water layer 4a softens city water flowing through it through the action of the first weakly acidic cation exchange resin 6a. The first soft water layer 4a is equipped with the first weakly acidic cation exchange resin 6a having hydrogen ions at the ends of its functional groups, and exchanges cations (calcium ions, magnesium ions) that are hardness components contained in the flowing city water with the hydrogen ions at the ends of the functional groups. In other words, the first weakly acidic cation exchange resin 6a adsorbs the hardness components and releases hydrogen ions into the water. This reduces the hardness components in the city water and increases the hydrogen ion concentration, thereby softening the city water.

[0040] More specifically, city water containing hardness components is passed through the inlet 2 in the first soft water layer 4a and passes through the first weakly acidic cation exchange resin 6a filled inside. This softens the city water that has passed through the first soft water layer 4a, and the softened city water is passed through the neutralization layer 4b as first softened water 110. However, the first softened water 110 softened by the first weakly acidic cation exchange resin 6a is acidic water with a low pH because it contains a large amount of hydrogen ions that have been exchanged for hardness components and have flowed out. Since softening is difficult to achieve when the pH is low (when the hydrogen ion concentration in the water is high), the first softened water 110 that has passed through the first soft water layer 4a is passed through the neutralization layer 4b to neutralize it and adjust the pH.

[0041] The neutralization layer 4b neutralizes the pH of the first soft water 110 containing hydrogen ions that has flowed out of the first soft water layer 4a by the action of the weakly basic anion exchange resin 7, converting it into neutral soft water, and passes the neutralized soft water 120 through the second soft water layer 4c. The neutralization layer 4b is provided with the weakly basic anion exchange resin 7 and adsorbs the hydrogen ions contained in the first soft water 110 together with anions (such as sulfate ions), thereby increasing the pH of the soft water.

[0042] More specifically, in the neutralization layer 4b, the first soft water 110 is passed from the first soft water layer 4a and flows through the weakly basic anion exchange resin 7 filled therein. As a result, the first soft water 110 flowing out from the first soft water layer 4a is neutralized, and the first soft water 110 is passed through the second soft water layer 4c as neutralized soft water 120 that is easily softened.

[0043] In the second soft water layer 4c, the neutralized soft water 120 neutralized in the neutralization layer 4b is passed through the second weakly acidic cation exchange resin 6b filled therein. As a result, hardness components that could not be removed in the first soft water layer 4a are exchanged with hydrogen ions possessed by the second weakly acidic cation exchange resin 6b, and the neutralized soft water 120 that has flowed into the second soft water layer 4c is softened. The softened neutralized soft water 120 is passed through the acidification layer 4d as second soft water 130.

[0044] The acidification layer 4d further softens the second softened water 130 containing hydrogen ions flowing out from the second softened water layer 4c by the action of the H-type strongly acidic cation exchange resin 8. The acidification layer 4d is provided with the H-type strongly acidic cation exchange resin 8 having hydrogen ions at the ends of its functional groups, and exchanges hardness components and cations other than hardness components (mainly sodium ions, etc.) remaining in the second softened water 130 flowing out from the second softened water layer 4c with the hydrogen ions at the ends of the functional groups.

[0045] More specifically, in the acidification layer 4d, the second softened water 130 containing hydrogen ions from the second softened water layer 4c is passed through the H-type strongly acidic cation exchange resin 8 filled therein. As a result, remaining hardness components and cations other than hardness components are exchanged for hydrogen ions, further softening and acidifying the second softened water 130. The softened and acidified second softened water 130 is passed through the outlet 5 as weakly acidic softened water. As a result, the hardness components and cations other than hardness components in the softened water are reduced, and the hydrogen ion concentration increases, thereby softening and acidifying the inflowing water. Note that if the hardness components and cations other than hardness components of city water are removed and almost no hardness components remain in the water after passing through the second softened water layer 4c, ion exchange by the H-type strongly acidic cation exchange resin 8 does not occur, and therefore the water quality hardly changes even when passing through the acidification layer 4d. Furthermore, when constructing a small cartridge-type water softener as in the present embodiment, the amount of ion exchange resin that can be filled is limited, which tends to result in insufficient water softening performance. Therefore, by providing an H-type strongly acidic cation exchange resin at the downstream end of the water treatment layer 4, the acidification performance can be compensated for, allowing the water softener to be made smaller without impairing the water softening performance.

[0046] Next, the purpose and effect of providing the neutralizing layer 4b between the first soft water layer 4a and the second soft water layer 4c will be described.

[0047] When water containing hardness components is softened using the weakly acidic cation exchange resin 6, the cations that constitute the hardness components in the city water are exchanged for hydrogen ions by the weakly acidic cation exchange resin 6, resulting in softening. During this process, hydrogen ions are released into the city water, which softens the water. At the same time, the city water becomes more acidic (its pH decreases) due to an increase in hydrogen ion concentration, making it more difficult for the hardness components to be adsorbed. Generally, water containing a large amount of permanent hardness components (e.g., sulfates such as calcium sulfate or chlorides such as magnesium chloride) is more likely to experience a decrease in pH during softening than water containing a large amount of temporary hardness components (e.g., carbonates such as calcium carbonate). This is because the bicarbonate ions contained in the temporary hardness components react with and are neutralized by the hydrogen ions released from the weakly acidic cation exchange resin 6 during the ion exchange reaction. In other words, although the hardness components exchange with hydrogen ions, the hydrogen ion concentration in the water is less likely to increase, making acidification less likely to occur. The weakly acidic cation exchange resin 6 can remove temporary hardness components. The weakly acidic cation exchange resin 6 can also remove some of the permanent hardness, but the city water quickly becomes acidic, making it difficult for the ion exchange reaction of the weakly acidic cation exchange resin 6 to proceed.

[0048] When weakly acidic soft water is extracted by passing water containing hardness components through the weakly acidic cation exchange resin 6, the hardness and pH of the extracted weakly acidic soft water depend on the concentration of hardness components in the city water and the ratio of temporary hardness to permanent hardness. If the flow time through the weakly acidic cation exchange resin 6 is the same, the higher the concentration of hardness components in the weakly acidic soft water, the higher the concentration of hardness components will be. Furthermore, if the temporary hardness ratio is high, the pH of the weakly acidic soft water will be high, and conversely, if the temporary hardness ratio is low, the pH of the weakly acidic soft water will be low and it may not be possible to completely remove the hardness components.

[0049] By providing a neutralization layer 4b between the first soft water layer 4a and the second soft water layer 4c, water acidified by the first soft water layer 4a to a level that makes it difficult for hard components to be adsorbed is neutralized by the neutralization layer 4b, and then softened again by flowing through the second soft water layer 4c. Even if city water is acidified to a level that makes it difficult for hard components to be adsorbed when it flows through the first soft water layer 4a, the acidified water is neutralized by flowing through the neutralization layer 4b, and the neutralized water is softened again by flowing through the second soft water layer 4c. Therefore, compared with a water treatment layer without a neutralization layer 4b, a water treatment layer 4 with a neutralization layer 4b can extract weakly acidic soft water with even fewer hard components. Furthermore, even if almost all of the hard components in city water can be removed without passing the city water through the neutralization layer 4b, the neutralization layer 4b can adjust the pH of the weakly acidic soft water to a more neutral (more alkaline). In other words, the neutralizing layer 4b can increase the pH of weakly acidic soft water.

[0050] Next, the purpose and effect of providing the acidifying layer 4d downstream of the second soft water layer 4c will be described.

[0051] By configuring city water to flow through the first soft water layer 4a, neutralization layer 4b, and second soft water layer 4c before flowing through the acidification layer 4d, city water is softened in the first soft water layer 4a and second soft water layer 4c, and then further softened in the acidification layer 4d. As a result, hardness components that were not completely removed by the softening in the first soft water layer 4a and second soft water layer 4c, as well as cations other than hardness components such as sodium ions, are removed in the acidification layer 4d, and hydrogen ions are released into the water. Therefore, soft water with fewer hardness components can be extracted compared to a configuration consisting of the first soft water layer 4a, neutralization layer 4b, and second soft water layer 4c. Furthermore, the extracted soft water can be adjusted to be more acidic compared to a configuration consisting of the first soft water layer 4a, neutralization layer 4b, and second soft water layer 4c. Even if almost all of the hardness components in the city water are removed when the water flows through the first soft water layer 4a and the second soft water layer 4c, cations such as sodium ions that are not removed in the first soft water layer 4a and the second soft water layer 4c are removed in the acidification layer 4d, making it possible to extract weakly acidic soft water that is biased towards acidity (for example, weakly acidic soft water with a pH of about 4).

[0052] Furthermore, by providing the acidifying layer 4d downstream of the second soft water layer 4c, hardness components that were not completely removed by the first soft water layer 4a and the second soft water layer 4c can be ion-exchanged. In other words, the H-type strongly acidic cation exchange resin 8 performs ion exchange on water that contains a relatively small amount of hardness components compared to city water, thereby suppressing wear of the H-type strongly acidic cation exchange resin 8 in the acidifying layer 4d.

[0053] Here, we will explain the regeneration of ion exchange resins. Compared to the H-type strongly acidic cation exchange resin 8, the weakly acidic cation exchange resin 6 has a narrower pH range in which the ion exchange reaction occurs. The ion exchange reaction does not proceed in the acidic range. However, it can be easily regenerated even with a low acid concentration in the regeneration solution used for regeneration. Specifically, in the case of the H-type strongly acidic cation exchange resin 8, dilute hydrochloric acid with a concentration of several percent or more is required to fully regenerate the ion exchange resin, whereas the weakly acidic cation exchange resin 6 can be regenerated with a concentration of about 0.01%. Therefore, when softening city water containing hardness components, by using as little H-type strongly acidic cation exchange resin 8 as possible and as much weakly acidic cation exchange resin 6 as possible, the used ion exchange resin can be easily recovered, regenerated, and reused for water softening.

[0054] As described above, the water softening device 1 according to the first embodiment can provide the following effects.

[0055] (1) The water softener 1 includes a water treatment layer 4 that produces weakly acidic soft water. The water treatment layer 4 includes a first soft water layer 4a, a neutralization layer 4b, a second soft water layer 4c, and an acidification layer 4d. The first soft water layer 4a and the second soft water layer 4c soften the inflowing water containing hardness components using a weakly acidic cation exchange resin 6. The neutralization layer 4b neutralizes the pH of the soft water that has passed through the first soft water layer 4a using a weakly basic anion exchange resin 7. The acidification layer 4d acidifies the pH of the soft water that has passed through the second soft water layer 4c using an H-type strongly acidic cation exchange resin 8. The water softener is configured so that city water flows through the first soft water layer 4a, neutralization layer 4b, second soft water layer 4c, and acidification layer 4d in this order.

[0056] With this configuration, city water containing hardness components flows out of the first soft water layer 4a before the pH of the city water decreases due to the softening treatment in the first soft water layer 4a. The water is neutralized in the neutralization layer 4b and softened in the second soft water layer 4c. This prevents the pH from decreasing and acidifying the water that flows through the first soft water layer 4a compared to a configuration without the neutralization layer 4b, facilitating the exchange of hardness components with hydrogen ions held by the weakly acidic cation exchange resin 6 in the second soft water layer 4c. Therefore, the water softener 1 can achieve improved water softening performance compared to a configuration without the neutralization layer 4b. Furthermore, even if almost all of the hardness components in hard water can be removed without passing city water through the neutralization layer 4b, the neutralization layer 4b can adjust the pH of the weakly acidic soft water to a more neutral level. In other words, if almost all of the hardness components in the water can be removed and the pH is 4 or below, the pH can be adjusted to the weakly acidic range (pH = 4 to 6).

[0057] Furthermore, with this configuration, city water is softened in the first soft water layer 4a and the second soft water layer 4c, and then further softened in the acidifying layer 4d. As a result, hardness components that were not completely removed by the softening in the first soft water layer 4a and the second soft water layer 4c, as well as cations other than hardness components such as sodium ions, are removed in the acidifying layer 4d, and hydrogen ions are released into the water. Therefore, the water softener 1 can produce weakly acidic soft water with fewer hardness components than a configuration consisting of the first soft water layer 4a, the neutralizing layer 4b, and the second soft water layer 4c.

[0058] Furthermore, compared to a configuration consisting of the first soft water layer 4a, the neutralization layer 4b, and the second soft water layer 4c, the weakly acidic soft water to be extracted can be adjusted to be more acidic.

[0059] (2) In the water softening device 1, the first soft water layer 4a, the neutralization layer 4b, the second soft water layer 4c, and the acidification layer 4d are configured by filling each ion exchange resin into a water treatment layer container 10 of the same shape, the upstream opening and the downstream opening of which are covered with a water-permeable outer diaphragm 9.

[0060] With this configuration, each layer of the water treatment layer 4 is detachable from the water softening device 1, and it is easy to change the sizes (ion exchange resin filling amounts) of the first soft water layer 4a, neutralization layer 4b, second soft water layer 4c, and acidification layer 4d using a fixed amount of ion exchange resin filled in the water treatment layer container 10 as one unit. Therefore, it is easy to change the sizes (ion exchange resin filling amounts) of the first soft water layer 4a, neutralization layer 4b, second soft water layer 4c, and acidification layer 4d according to the concentrations of hardness components and other ions contained in city water, and adjust the hardness and pH of the weakly acidic soft water to the desired values.

[0061] Furthermore, by making all the water treatment layer containers 10 the same shape, any water treatment layer container 10 can be installed at any position in the housing 3. In other words, the layers of the water treatment layer 4 can be easily rearranged, making it easier to form the configuration required to obtain the desired soft water performance.

[0062] The present disclosure has been described above based on the embodiments. These embodiments are merely examples, and it will be understood by those skilled in the art that various modifications are possible in the combination of each component or each treatment process, and that such modifications are also within the scope of the present disclosure.

[0063] In the water softening device 1 according to the first embodiment, the shapes of the water treatment layer containers 10 are all the same, but this is not limiting. The shapes of the water treatment layer containers 10 may be different from each other.

[0064] In the water softening device 1 according to the first embodiment, the first soft water layer 4a, the neutralization layer 4b, the second soft water layer 4c, and the acidification layer 4d are partitioned by identically shaped water treatment layer containers 10 whose upstream and downstream openings are covered with water-permeable outer diaphragms 9, and each container is filled with ion exchange resin, but this is not limitative. For example, each container may have a different flow path length, or may have a shape other than a cylinder. Even in this case, the same effects as those of the first embodiment can be obtained.

[0065] (Embodiment 2) Next, a mist spraying device 11 according to embodiment 2 of the present disclosure will be described with reference to Figs. 3 to 5. Fig. 3 is a schematic diagram showing an example of the installed state of the mist spraying device 11. Fig. 4 is a conceptual diagram showing the mist spraying device 11 according to embodiment 2 of the present disclosure. Fig. 5 is a configuration diagram showing the flow path of the mist spraying device according to embodiment 2 of the present disclosure. Note that each configuration is illustrated schematically in Figs. 3 to 5.

[0066] As shown in Fig. 3, the house 200 is a building where residents can live private lives and may include a bedroom, a kitchen, a living room, a toilet, etc. For ease of explanation, only a bathroom 220 is shown in Fig. 3. The house 200 is equipped with a mist spray device 11.

[0067] The mist spraying device 11 is installed, for example, in the attic space 210 of the bathroom 220. More precisely, the mist spraying device 11 is arranged so that a micro mist generating unit 12a and a splash mist generating unit 12b (described later) are exposed inside the bathroom 220. The mist spraying device 11 is connected to a city water inlet pipe 230 for guiding city water into the inside of the mist spraying device 11. More precisely, one end of the city water inlet pipe 230 is connected to the flow path 13 shown in Figure 4, and the other end of the city water inlet pipe 230 is connected to city water.

[0068] 5, the mist spraying device 11 includes a water softening device 1a, a mist generating unit 12 that atomizes city water or weakly acidic soft water, a first flow path 21 that supplies weakly acidic soft water to the mist generating unit 12 via the water softening device 1a, a second flow path 22 that supplies city water to the mist generating unit 12 without passing through the water softening device 1a, switching valves 18 and 19 that switch between the first flow path 21 and the second flow path 22, and a control unit 20 that controls the operating mode and the switching valves 18 and 19. The configuration of the water softening device 1a is the same as that of the water softening device 1 according to the first embodiment. Hereinafter, the description of the contents already described in the first embodiment will be omitted as appropriate.

[0069] (Overall Configuration) The mist sprayer 11 is a device that generates weakly acidic soft water that can be used as domestic water from city water supplied from an external source, and further atomizes weakly acidic soft water or city water containing hard components. The mist sprayer 11 has a micro mist mode and a splash mist mode. The micro mist mode is also referred to as the first operating mode, and the splash mist mode is also referred to as the second operating mode.

[0070] The micro mist mode is a mode in which micro mist 250, a mist with a diameter of about several micrometers, is generated from the weakly acidic soft water obtained by the water softening device 1a. The micro mist mode is used to obtain beauty effects such as improving hair quality and moisturizing effects by turning the weakly acidic soft water into a mist and spraying it on a person. In the micro mist mode, city water flows through the flow path 13, flow path 14, the water softening device 1a, flow path 15, flow path 17, and the micro mist generating unit 12a in this order. Furthermore, the amount of water used per hour in the micro mist mode is less than the amount of water used per hour in the splash mist mode.

[0071] The splash mist mode is a mode in which splash mist 260, which is mist having a diameter larger than several micrometers, is generated from city water. The splash mist mode is used to heat the bathroom by spraying warm water or to cleanse the body and the bathroom. In the splash mist mode, city water flows through the flow path 13, flow path 16, flow path 17, and splash mist generating unit 12b in this order. The amount of water used per hour in the splash mist mode is also greater than the amount of water used per hour in the micro mist mode.

[0072] As shown in Figures 4 and 5, the mist spraying device 11 is composed of a water softening device 1a that produces weakly acidic soft water from city water, a mist generating unit 12 that atomizes the city water or weakly acidic soft water, a flow path 13 into which city water flows from the outside, flow paths 14 to 17 that supply the weakly acidic soft water or city water to the mist generating unit 12, a switching valve 18 and a switching valve 19 that switch the flow paths, and a control unit 20 that controls the operating mode and the switching valve.

[0073] The water softening device 1a has the same configuration as described in the first embodiment, with the inlet 2 connected to the flow path 13 and the outlet 5 connected to the flow path 15 (see FIG. 1).

[0074] The flow path 13 is connected to a city water inlet pipe 230. The mist spraying device 11 extracts city water containing hardness components or weakly acidic soft water after softening treatment from the flow path 17 using the city water pressure, and generates a mist of the city water containing hardness components or weakly acidic soft water by the mist generating unit 12.

[0075] Between the flow path 13 and the mist generating unit 12, the water softening device 1a, the flow path 14, the flow path 15, the flow path 16, and the flow path 17 are provided.

[0076] The flow path 14 is a flow path that connects the flow path 13 to the water softening device 1a.

[0077] The flow path 15 is a flow path that connects the water softening device 1 a to the flow path 17 .

[0078] The flow path 16 is a flow path that connects the flow path 13 to the flow path 17 without passing through the water softening device 1a.

[0079] In other words, in the micro mist mode, city water containing hard components flows through flow path 13, flow path 14, water softener 1a, flow path 15, and flow path 17 in this order, where it is softened, and the softened, weakly acidic soft water is supplied to micro mist generator 12a (the flow indicated by the white arrows in FIG. 5 ). In other words, in the micro mist mode, mist sprayer 11 supplies water to mist generator 12 via first flow path 21. In the splash mist mode, city water containing hard components flows through flow path 13, flow path 16, and flow path 17 in this order, where it is supplied to splash mist generator 12b as city water containing hard components (the flow indicated by the black arrows in FIG. 5 ). In other words, in the splash mist mode, mist sprayer 11 supplies water to mist generator 12 via second flow path 22.

[0080] (Switching Valve) The switching valve 18 is provided at the connection between the flow path 13 and the flow paths 14 and 16. The switching valve 18 directs city water flowing in from the flow path 13 to the flow path 14 or the flow path 16. In other words, the switching valve 18 switches the flow direction of the water. The switching valve 18 is a so-called three-way valve, and its type is not particularly limited. The switching valve 18 is, for example, a solenoid valve that controls the opening and closing of each flow path using an electric signal.

[0081] The switching valve 19 is provided at the connection between the flow path 17 and the flow paths 15 and 16. The switching valve 19 guides water flowing in from the flow path 14 or the flow path 16 to the flow path 17. In other words, the switching valve 19 switches the flow direction of the water. The switching valve 19 is a so-called three-way valve, and its type is not particularly limited. The switching valve 19 is, for example, an electromagnetic valve that controls the opening and closing of each flow path using an electric signal.

[0082] Furthermore, the switching valve 18 and the switching valve 19 are each connected to a control unit 20 (described later) wirelessly or via wire so as to be able to communicate with each other.

[0083] (Mist Generating Unit) The mist generating unit 12 atomizes city water containing hardness components supplied through the flow path 17 or weakly acidic soft water softened through the water softening device 1a. There are no particular limitations on the means for generating mist, and any general-purpose means can be used, such as mist generation using a nozzle with a multi-hole outlet or mist generation using a centrifugal crushing method.

[0084] In this embodiment, the mist generating unit 12 includes a micro mist generating unit 12a and a splash mist generating unit 12b.

[0085] In micro mist mode, the micro mist generating unit 12a sprays the weakly acidic soft water extracted from the water softening device 1a as micro mist 250. In this embodiment, the micro mist generating unit 12a is a nozzle with a porous outlet (not shown). The average pore size of the holes in the micro mist generating unit 12a is smaller than the average pore size of the holes in the splash mist generating unit 12b, which will be described later. In other words, the micro mist 250 sprayed from the micro mist generating unit 12a is a finer mist than the splash mist 260.

[0086] In splash mist mode, the splash mist generating unit 12b sprays city water containing hardness components that has passed through the flow paths 13, 15, and 17 as splash mist. In this embodiment, the splash mist generating unit 12b is a nozzle with a porous outlet (not shown). The average pore size of the holes in the splash mist generating unit 12b is larger than the average pore size of the holes in the micro mist generating unit 12a. In other words, the splash mist 260 sprayed from the splash mist generating unit 12b has a larger particle size than the micro mist 250.

[0087] (Heating Unit) The heating unit 31 heats the water flowing into the mist generating unit 12, thereby warming the water or vaporizing it. The heating unit 31 is, for example, an electric heater. The heating unit 31 may be provided anywhere as long as it is capable of heating the water flowing into the mist generating unit 12. In this embodiment, two heating units 31 are provided, one near each of the flow paths 15 and 16. In other words, the heating unit 31 heats the flow paths 15 and 16, thereby heating the water flowing through the flow paths 15 and 16.

[0088] (Controller) The controller 20 controls the operations of the mist generator 12 and the switching valves 18 and 19 to switch the operation mode. At this time, the controller 20 switches the switching valves 18 and 19 depending on the operation mode.

[0089] The control unit 20 has a computer system with a processor and memory, and the processor executes a program stored in the memory, causing the computer system to function as the control unit.

[0090] (Mist Spraying) Next, a description will be given of the mist spraying operation by the mist spraying device 11. The mist spraying operation by the mist spraying device 11 is switched depending on the operation mode switched by the control unit 20.

[0091] As described above, the operation modes include the micro mist mode (first operation mode) and the splash mist mode (second operation mode).

[0092] In the micro-mist mode, the mist sprayer 11 supplies weakly acidic soft water to the micro-mist generator 12a through the first flow path 21 (via the water softener 1a), atomizes a predetermined amount of water, and sprays it outside (to the bathroom 220). At this time, the controller 20 sets the selector valve 18 to allow water to pass through the flow paths 13 and 14, and sets the selector valve 19 to allow water to pass through the flow paths 15 and 17.

[0093] On the other hand, in the splash mist mode, the mist sprayer 11 supplies city water to the splash mist generator 12b through the second flow path 22, atomizes a predetermined amount of water, and sprays it outside (bathroom 220). At this time, the control unit 20 switches the switching valve 18 to connect the flow path 13 and the flow path 16, and switches the switching valve 19 to connect the flow path 16 and the flow path 17.

[0094] In this way, the mist spraying device 11 is configured to be switchable between a first operating mode in which a mist of weakly acidic soft water can be sprayed and a second operating mode in which a mist of city water containing hardness components can be sprayed.

[0095] This makes it possible to switch between mist of weakly acidic soft water and mist of city water containing hardness components as needed. As a result, wear on the water treatment layer 4 inside the water softening device 1a can be reduced compared to when only mist of weakly acidic soft water can be sprayed. In other words, the amount of water circulating inside the water softening device 1a can be kept to a minimum, and the amount of hardness components adsorbed in the water softening device 1a can be kept to a minimum. This reduces the frequency of maintenance (e.g., regeneration or replacement) of the water softening device 1a.

[0096] Furthermore, when the water softener 1a is installed inside the mist sprayer 11, the water softening performance of the water softener 1a is maintained or improved while being made smaller, which prevents the mist sprayer 11 from becoming larger. In other words, ease of installation can be maintained when the mist sprayer 11 is installed in a narrow space such as above the ceiling.

[0097] As described above, the mist spraying device 11 according to the second embodiment can provide the following effects.

[0098] (1) The mist spray device 11 includes a water softener 1a, a mist generating unit 12 that atomizes city water or weakly acidic soft water containing hardness components, a first flow path 21 that supplies weakly acidic soft water to the mist generating unit 12 via the water softener 1a, a second flow path 22 that supplies city water to the mist generating unit 12 without passing through the water softener 1a, a switching valve 18 and a switching valve 19 that switch between the first flow path 21 and the second flow path 22, and a control unit 20 that controls the operating mode and the switching valve.

[0099] With this configuration, in the micro mist mode, weakly acidic soft water is supplied to the micro mist generating unit 12a through the first flow path 21, and a micro mist of the weakly acidic soft water is generated from the micro mist generating unit 12a, which can be sprayed outside (for example, into the bathroom 220).

[0100] In the splash mist mode, city water containing hardness components is supplied to the splash mist generating unit 12b through the second flow path 22, and the splash mist generating unit 12b generates splash mist that can be sprayed outside (for example, the bathroom 220).

[0101] Therefore, by switching between mist of weakly acidic soft water and mist of city water containing hardness components as needed, the mist sprayer 11 can reduce wear on the water treatment layer 4 inside the water softening device 1a compared to when only mist of weakly acidic soft water can be sprayed, which means that the maintenance frequency of the water softening device 1a can be reduced.

[0102] The present disclosure has been described above based on the embodiments. These embodiments are merely examples, and it will be understood by those skilled in the art that various modifications are possible in the combination of the respective components or treatment processes, and that such modifications are also within the scope of the present disclosure.

[0103] For example, in the second embodiment, an example is shown in which only the water flowing through the second flow path 22, which does not have the water softening device 1a, is atomized in the splash mist mode, but this is not limiting. Specifically, in the splash mist mode, a mode may be provided in which mist is generated using water flowing through both the first flow path 21 and the second flow path 22.

[0104] Furthermore, the water treatment layer 4 of the water softening device 1 according to the first embodiment includes the first soft water layer 4 a, the neutralization layer 4 b, the second soft water layer 4 c, and the acidification layer 4 d, but is not limited thereto. For example, the water treatment layer 4 does not necessarily have to include the second soft water layer 4 c.

[0105] In this case, the water softening device 1 comprises a housing 3 having an internal space, an inlet 2 for allowing water to be treated to flow into the internal space, a water treatment tank 4 for removing hardness components from the water to be treated and producing weakly acidic soft water, and an outlet 5 for discharging the weakly acidic soft water from the internal space. The water treatment tank 4 comprises a first soft water tank 4a for removing hardness components from the water to be treated using a weakly acidic cation exchange resin 6, a neutralization tank 4b located downstream of the first soft water tank 4a for neutralizing the water to be treated using a weakly basic anion exchange resin 7, and an acidification tank 4d located downstream of the neutralization tank 4b for acidifying the water to be treated and removing hardness components from the water to be treated using an H-type strongly acidic cation exchange resin 8.

[0106] Although this configuration reduces the water softening performance, it is possible to minimize the configuration of the water softening device 1 and reduce manufacturing costs. In other words, it is desirable for designers to change the combination of water treatment layers as appropriate, taking into consideration the required water softening performance and manufacturing costs.

[0107] The water softening device according to the present disclosure can be applied to household electrical appliances and the like.

[0108] REFERENCE SIGNS LIST 1 Water softening device 1a Water softening device 2 Inlet 3 Housing 3a Housing opening / closing section 3b Side opening 4 Water treatment layer 4a First soft water layer 4b Neutralization layer 4c Second soft water layer 4d Acidification layer 5 Outlet 6 Weakly acidic cation exchange resin 6a First weakly acidic cation exchange resin 6b Second weakly acidic cation exchange resin 7 Weakly basic anion exchange resin 8 H-type strongly acidic cation exchange resin 9 Water-permeable outer diaphragm 10 Water treatment layer container 11 Mist spray device 12 Mist generating section 12a Micro mist generating section 12b Splash mist generating section 13 Flow path 14 Flow path 15 Flow path 16 Flow path 17 Flow path 18 Switching valve 19 Switching valve 20 Control section 21 First flow path 22 Second flow path 31 Heating section 90 Protrusion 91 Protrusion 101 One surface 102 One surface 110 First soft water 120 Neutralized soft water 130 Second soft water 200 Residence 210 Attic space 220 Bathroom 230 City water inlet pipe 250 Micro mist 260 Splash mist

Claims

1. A water treatment system comprising: a housing having an internal space; an inlet for introducing water to be treated into the internal space; a water treatment layer disposed in the internal space and removing hardness components from the water to be treated to produce weakly acidic soft water; and an outlet for discharging the weakly acidic soft water from the internal space, wherein the water treatment layer comprises: a first soft water layer containing a weakly acidic cation exchange resin and removing hardness components from the water to be treated with the weakly acidic cation exchange resin; a neutralization layer containing a weakly basic anion exchange resin and disposed downstream of the first soft water layer and neutralizing the water to be treated with the weakly basic anion exchange resin; and a second soft water layer containing the weakly acidic cation exchange resin and disposed downstream of the neutralization layer and removing hardness components from the water to be treated with the weakly acidic cation exchange resin. an acidification layer that contains an H-type strongly acidic cation exchange resin and is located downstream of the second soft water layer, and that acidifies the water to be treated with the H-type strongly acidic cation exchange resin and removes hardness components from the water to be treated with the H-type strongly acidic cation exchange resin.

2. The water softening device according to claim 1, wherein the first soft water layer produces first soft water by removing hardness components from city water with the weakly acidic cation exchange resin; the neutralization layer produces neutralized soft water by neutralizing the first soft water with the weakly basic anion exchange resin; the second soft water layer produces second soft water having fewer hardness components than the first soft water by removing hardness components from the neutralized soft water with the weakly acidic cation exchange resin; and the acidification layer produces the weakly acidic soft water by removing hardness components from the second soft water with the H-type strongly acidic cation exchange resin and acidifying the second soft water with the H-type strongly acidic cation exchange resin.

3. The water softening device according to claim 1, wherein at least one of the water treatment layers is detachably provided on the housing.

4. The water softening device according to claim 3, wherein the first soft water layer is provided with a water-permeable outer diaphragm that is detachably attached to the housing and that holds the weakly acidic cation exchange resin therein.

5. The water softening device according to claim 3, wherein the neutralization layer is provided detachably with respect to the housing and includes a water-permeable outer diaphragm that holds the basic anion exchange resin therein.

6. The water softening device according to claim 3, wherein the second soft water layer is provided with a water-permeable outer diaphragm that is detachably attached to the housing and that holds the weakly acidic cation exchange resin therein.

7. The water softening device according to claim 3, wherein the acidifying layer is provided detachably with respect to the housing and includes a water-permeable outer diaphragm that holds the H-type strongly acidic cation exchange resin therein.

8. A water softening device as described in claims 4 to 7, wherein each layer of the water treatment layer is cylindrical, each layer of the water treatment layer includes an upstream opening and a downstream opening in the water flow direction, and the upstream opening and the downstream opening are covered by the water-permeable outer diaphragm.

9. The water softening device of claim 8, wherein the water-permeable outer membrane is a nonwoven fabric or a polyester mesh.

10. The water softening device of claim 8, wherein all layers of the water treatment layer have the same outer shape.

11. The water softening apparatus according to claim 1, wherein the amount of the weakly acidic cation exchange resin packed in the first soft water layer is greater than the amount of the weakly acidic cation exchange resin packed in the second soft water layer.

12. A mist spraying device that atomizes and sprays the weakly acidic soft water obtained from the water softening device according to claim 1.

13. A mist spray device as described in claim 12, comprising: a mist generating unit that atomizes water; a first flow path that supplies water to the mist generating unit via the water softening device; a second flow path that supplies water to the mist generating unit without passing through the water softening device; a switching valve that switches between the first flow path and the second flow path; and a control unit that controls the operation modes and the switching valve, wherein the operation modes include a first operation mode that atomizes a predetermined amount of water, and a second operation mode that atomizes a larger amount of water than in the first operation mode, and wherein the control unit uses the switching valve to allow water to pass through the first flow path in the first operation mode, and uses the switching valve to allow water to pass through the second flow path in the second operation mode.

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