VALVE DEVICE AND HOT WATER SUPPLY DEVICE

A valve device includes: a case having a valve chamber and first to third water communication ports communicating with the valve chamber; first and second valve bodies disposed in the valve chamber; and a shaft body connected with the first valve body. The first valve body is rotated about a central axis of the shaft part. The second valve body is rotated about the central axis together with the first valve body. When rotated about the central axis in a first angle region, the first valve body changes a first flow rate, i.e., a flow rate of water between the first and third water communication ports, and a second flow rate, i.e., a flow rate of water between the second and third water communication ports. When the first valve body is rotated about the central axis in a second angle region, the second valve body changes the second flow rate.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the priority benefit of Japan application serial No. 2022-174703, filed on Oct. 31, 2022. The entirety of the above-mentioned patent application is hereby incorporated by reference herein and made a part of this specification.

BACKGROUND

Technical Field

The invention relates to a valve device and a hot water supply device.

Description of Related Art

For example, Japanese Patent No. 5004674 (Patent Document 1) discloses a mixing valve. The mixing valve disclosed in Patent Document 1 includes a case, a valve body, and a shaft part. The case is provided with a valve chamber, a water inlet in communication with the valve chamber, a hot water inlet, and an outlet. The valve body is disposed in the valve chamber. The valve body is in a tubular shape extending along the direction of the central axis of the shaft part. In the direction of the central axis of the shaft part, the valve body has a first end and a second end on a side opposite to the first end. The first end of the valve body is blocked, and the second end of the valve body is not blocked. The shaft part is connected with the first end of the valve body. The valve body is rotated about the central axis of the shaft part. An opening part is formed in the valve body.

When the valve body is rotated about the central axis of the shaft part in a first angle region, as the valve body approaches the second angle region, the opening area of the opening part of the valve body when viewed from the water inlet decreases. When the valve body is rotated about the central axis of the shaft part in the first angle region, the opening area of the opening part of the valve body when viewed from the hot water inlet increases. Therefore, in the mixing valve of Patent Document 1, by rotating the valve body about the central axis of the shaft part in the first angle region, the ratio of the flow rate of water (hot water) flowing from the hot water inlet to the outlet to the flow rate of water flowing from the water inlet to the outlet is adjusted.

When the valve body is rotated about the central axis of the shaft part in the second angle region, the opening area of the opening part of the valve body when viewed from the water inlet is maintained at the minimum (maintained at 0). When the valve body is rotated about the central axis of the shaft part in the second angle region, as the valve body moves away from the first angle region, the opening area of the opening part of the valve body when viewed from the water inlet decreases. Therefore, in the mixing valve of Patent Document 1, by rotating the valve body about the central axis of the shaft part in the second angle region, the flow rate of water (hot water) flowing from the hot water inlet to the outlet is adjusted.

PRIOR ART DOCUMENT(S)

The mixing valve of Patent Document 1 is used in a hot water supply device, for example. In the hot water supply device having the mixing valve of Patent Document 1, a first pipe is connected to the water inlet, a second pipe is connected to the hot water inlet, and a third pipe is connected to the outlet. The water inlet is connected with a tap water pipe via the first pipe. The hot water inlet is connected with a heat exchanger via the second pipe. The hot water supply device having the mixing valve of Patent Document 1 supplies hot water via the third pipe.

In the hot water supply device having the mixing valve of Patent Document 1, by rotating the valve body about the central axis of the valve part in the first angle region, the temperature of the supplied hot water is adjusted. Even if the valve body is rotated to the maximum about the central axis of the shaft part in the first angle region, due to the upper limit of the heating capability of the heat exchanger, the temperature of the hot water may be insufficient. In such case, by rotating the valve body about the central axis of the shaft part in the second angle region, the flow rate of the water (hot water) from the hot water inlet to the outlet is adjusted, and the temperature of the supplied hot water increases.

However, in the hot water supply device using the mixing valve of Patent Document 1, when the valve body is rotated about the central axis of the shaft part in the second angle region, the flow rate of the water (hot water) flowing from the hot water inlet to the outlet varies significantly at each rotational angle, and it is difficult to adjust the temperature of the supplied hot water. The invention provides a valve device and a hot water supply device with which the temperature of the supplied hot water is adjusted easily.

SUMMARY

A valve device according to the invention includes a case, a first valve body and a second valve body, and a shaft body connected with the first valve body. The case has a valve chamber, a first water communication port, a second water communication port, and a third water communication port are in communication with the valve chamber. The first valve body and the second valve body are disposed in the valve chamber. The first valve body is rotated about a central axis of the shaft part. The second valve body is rotated about the central axis together with the first valve body. When the first valve body is rotated about the central axis in a first angle region, a first flow rate and a second flow rate are changed by the first valve body, wherein the first flow rate is a flow rate of water flowing between the first water communication port and the third water communication port, and the second flow rate is a flow rate of water flowing between the second water communication port and the third water communication port. When the first valve body is rotated about the central axis in a second angle region, the second flow rate is changed by the second valve body.

In the valve device, it may also be that the first flow rate decreases as the first valve body approaches the second angle region when the first valve body is rotated about the central axis in the first angle region, and the first flow rate is maintained at a minimum when the first valve body is rotated in the second angle region, and the second flow rate increases as the first valve body approaches the second angle region when the first valve body is rotated about the central axis in the first angle region, and the second flow rate decreases as the first valve body moves away from the first angle region when the first valve body is rotated about the central axis in the second angle region.

In the valve device, it may also be that a ratio of the first flow rate with respect to a sum of the first flow rate and the second flow rate decreases linearly as the first valve body approaches the second angle region when the first valve body is rotated about the central axis in the first angle region.

In the valve device, it may also be that the first valve body is in a tubular shape extending along a direction of the central axis, in the direction of the central axis, the first valve body has a first end and a second end on a side opposite to the first end, an internal space of the first valve body is blocked at the first end and is partially blocked at the second end by the second valve body, in the first valve body, a first opening part and a second opening part in communication with the internal space of the first valve body are formed, in the second valve body, a third opening part in communication with the internal space of the first valve body is formed, a first opening area, as an opening area of the first opening part when viewed from the first water communication port, decreases as the first valve body approaches the second angle region when the first valve body is rotated about the central axis in the first angle region, and is maintained at a minimum when the first valve body is rotated about the central axis in the first angle region, and a second opening area, as an opening area of the second opening part when viewed from the second water communication port, increases as the first valve body approaches the second angle region when the first valve body is rotated about the central axis in the first angle region, and is maintained at a maximum when the first valve body is rotated about the central axis in the second angle region, and a third opening area, as an opening area of the third opening part when viewed from the third water communication port, is maintained at a maximum vale when the first valve body is rotated about the central axis in the first angle region, and decreases as the first valve body moves away from the first angle region when the first valve body is rotated about the central axis in the second angle region.

In the valve device, it may also be that the second valve body is engaged with the second end to be not rotatable about the central axis.

A hot water supply device includes a first pipe, a second pipe, and a third pipe, a heat exchanger, and the valve device. The first water communication port is connected with a tap water pipe by using the first pipe. The second water communication port is connected with the heat exchanger by using the second pipe. The third water communication port is connected with the third pipe. Hot water is supplied via the third pipe.

DESCRIPTION OF THE EMBODIMENTS

According to the valve device and the hot water supply device of the invention, it is easy to adjust the temperature of the supplied hot water.

Details of the embodiments are described with reference to the drawings. In the following drawings, like or equivalent components are labeled with like reference symbols, and the same description will not be made repetitively. A valve device according to the embodiment is set as a valve device100, and a hot water supply device according to the embodiment is set as a hot water supply device200.

(Configuration of the Valve Device100)

In the following, the configuration of the valve device100is described.

The valve device100is a mixing valve, for example.FIG.1Ais a first side view of the valve device100.FIG.1Bis a second side view of the valve device100.FIG.2is a cross-sectional view taken along II-II inFIG.1A.FIG.3is a cross-sectional view taken along III-III inFIG.1B.FIG.4Ais a first side view of a case10.FIG.4Bis a second side view of the case10.FIG.4Cis a bottom view of the case10.FIG.5Ais a first side view of a first valve body20.FIG.5Bis a second side view of the first valve body20.FIG.5Bis a third side view of the first valve body20.FIG.5Bis a fourth side view of the first valve body20.FIG.6is a cross-sectional view taken along VI-VI inFIG.5B.FIG.7is a cross-sectional view taken along VII-VII inFIG.5B.FIG.8is a front view of the first valve body20and a second valve body30.FIG.9is a cross-sectional view taken along IX-IX inFIG.8.FIG.10is a bottom view of the first valve body20and the second valve body30. As shown inFIGS.1A to10, the valve device100includes the case10, a collar11, an O-ring12, the first valve body20, the shaft body, an O-ring22, the second valve body30, a stepping motor40, a thermistor50(not shown), and a controller60(not shown).

The case10has a valve chamber10a, the first water communication port10b, the second water communication port10c, the third water communication port10d, and an insertion hole10e. The valve chamber10ais an internal space of the case10in which the first valve body20and the second valve body30are disposed. The first water communication port10b, the second water communication port10c, the third water communication port10d, and the insertion hole10eare in communication with the valve chamber10a.

The case10is further provided with a first flow path10f, a second flow path10g, a third flow path10h. The extending direction of the shaft body21is a first direction DR1. The first flow path10fextends along a second direction DR2. The second direction DR2is a direction orthogonal to the first direction DR1. The first flow path10fconnects the valve chamber10aand the first water communication port10b. The second path10gextends along a third direction DR3. The third direction DR3is a direction orthogonal to the first direction DR1and the second direction DR2. The second flow path10gconnects the valve chamber10aand the second water communication port10c. The third path10hextends along the first direction DR1. The third flow path10hconnects the valve chamber10aand the third water communication port10d. The insertion hole10eis in communication with the valve chamber10afrom a side opposite to the third water communication port10d.

The case10is further provided with a first blocking part10i, a second blocking part10j, and a third blocking part10k. The first blocking part10iis disposed on the inner wall surface of the first flow path10f. The first blocking part10iextends along the first direction DR1from the inner wall surface of the first flow path10f. The second blocking part10jis disposed on the inner wall surface of the second flow path10g. The second blocking part10jextends along the first direction DR1from the inner wall surface of the second flow path10g. The third blocking part10kis disposed on the inner wall surface of the third flow path10h. The third blocking part10kis extends from the inner wall surface of the third flow path10hwithin a surface orthogonal to the first direction DR1.

The first flow path10fis partially blocked by the first blocking part10i, and is connected with the valve chamber10athrough an opening part101. When viewed from the first water communication port10b, the opening part101is in a semi-circular shape, for example. The second flow path10gis partially blocked by the second blocking part10j, and is connected with the valve chamber10athrough an opening part10m. When viewed from the second water communication port10c, the opening part10mis in a semi-circular shape, for example. The opening part10m, for example, is in a shape reversing the opening part101upside down. The third flow path10his partially blocked by the third blocking part10k, and is connected with the valve chamber10athrough an opening part10n. When viewed from the third water communication port10d, the opening part10nis in a fan shape, for example.

The collar11is inserted into the insertion hole10e. The outer circumferential surface of the collar11is in contact with the inner wall surface of the insertion hole10e. An annular groove11ais formed on the inner wall surface of the collar11. The annular groove11aextends along a circumferential direction. The circumferential direction is a direction along the circumference in which the central axis of the shaft body21is set as the center when viewed along the first direction DR1. The O-ring12is disposed in the annular groove11a. Accordingly, the watertightness between the outer circumferential surface of the collar11and the inner wall surface of the insertion hole10eis secured. A through hole11bis formed in the collar11. The through hole11bpenetrates through the collar11along the first direction DR1.

The first valve body20is in a tubular shape extending along the first direction DR1. In the first direction DR1, the first valve body20has a first end20aand a second end20b. The second end20bis an end on the side opposite to the first end20a. The first valve body20is blocked at the first end20a. The first valve body20is not blocked at the second end20b.

The first valve body20has a first portion20cand a second portion20d. The first portion20cand the second portion20dare arranged side-by-side in the first direction DR1. The first blocking part10ifaces the second portion20d. The second blocking part10jfaces the first portion20c. In the first valve body20, the first opening part20eand the second opening part20fare formed. More specifically, the first opening part20eis formed in the first portion20c, and the second opening part20fis formed in the second portion20d. The first opening part20eand the second opening part20fpenetrate through the first valve body20to be in communication with the internal space of the first valve body20.

The first opening part20eextends along the circumferential direction. In the circumferential direction, the first opening part20ehas a first end20eaand a second end20eb. The second end20ebis an end on the side opposite to the first end20ea. The width of the first opening part20ein the first direction DR1is set as a width W1. The width D1decreases toward the second end20eb. The angle formed by a hypothetical line passing through the first end20eaand the central axis of the shaft body21and a hypothetical line passing through the second end20eband the central axis of the shaft body21when viewed in the first direction DR1is set as a first angle θ1.

The second opening part20fextends along the circumferential direction. In the circumferential direction, the second opening part20fhas a first end20faand a second end20fb. The second end20fbis an end on the side opposite to the first end20fa. A position between the first end20faand the second end20fbin the circumferential direction is set as an intermediate position P. The width of the second opening part20fin the first direction DR1is set as a width W2. The width W2increases toward the intermediate position P, and reaches the maximum at the intermediate position P. The width W2is constant between the intermediate position P and the second end20fb, and is maintained at the maximum.

The angle formed by a hypothetical line passing through the first end20faand the central axis of the shaft body21and a hypothetical line passing through the second end20fband the central axis of the shaft body21when viewed in the first direction DR1is set as a second angle θ2. The second angle θ2is greater than the first angle θ1. The angle formed by a hypothetical line passing through the first end20faand the central axis of the shaft body21and a hypothetical line passing through the intermediate position P and the central axis of the shaft body21when viewed in the first direction DR1is set as a third angle θ3. The third angle θ3is equal to the first angle θ1.

The shaft body21extends along the first direction DR1. The shaft body21is connected with the first end20a. The shaft body21is inserted into the through hole11b. The outer circumferential surface of the shaft body21is in contact with the inner wall surface of the through hole11b. An annular groove21ais formed on the outer circumferential surface of the shaft body21. The annular groove21aextends along the circumferential direction. The annular groove21ais a portion at the outer circumferential surface of the shaft body21facing the inner wall surface of the through hole11b. An O-ring22is disposed in the annular groove21a. Accordingly, the watertightness between the inner wall surface of the through hole11band the outer circumferential surface of the shaft body21is secured.

The shaft body21has involute serrations21b. The involute serrations21bare provided on the tip end side of the shaft body21with respect to the portion of the shaft body21located in the through hole11b. The involute serrations21bare at a position protruding from the case10.

The second valve body30has a tubular part31, a bottom part32, and a rib33. The tubular part31is in a tubular shape extending along the first direction DR1. The second valve body30is engaged with the second end20bin the cylindrical part31to be not rotatable about the central axis of the shaft body21. Multiple convex parts20gare formed on the inner circumferential surface of the first valve body20located at the second end20b. Multiple concave parts31aare formed on the outer circumferential surface of the tubular part31. By engaging the respective convex parts20gwith the respective concave parts31a, the tubular part31is engaged with the second end20bto be not rotatable about the central axis of the shaft body21. The outer circumferential surface of the tubular part31is in contact with the inner circumferential surface of the first valve body20located at the second end20b.

It may be that the concave parts31aare disposed to exhibit rotational symmetry of one time about the central axis of the shaft body21when viewed along the first direction DR1. It may also be that the convex parts20gare disposed to exhibit rotational symmetry of one time about the central axis of the shaft body21when viewed along the first direction DR1. In other words, the concave parts31amay be disposed so as not to overlap the position before rotation unless the concave parts31arotate 360° about the central axis of the shaft body21when viewed in the first direction DR1, and the convex parts20gmay be disposed so as not to overlap the position before rotation unless the convex parts20grotate 360° about the central axis of the shaft body21when viewed in the first direction DR1. Accordingly, the second valve body30is prevented from being installed to the first valve body20at an erroneous angle is prevented.

In the first direction DR1, the tubular part31has a first end31band a second end31c. The second end31cis an end on the side opposite to the first end31b. The bottom part32is linked with the second end31c. The third opening part32ais formed in the bottom part32. The third opening part32apenetrates through the bottom part32to be in communication with the internal space of the first valve body20. In the circumferential direction, the third opening part32ahas a first end32aaand a second end32ab. The second end32abis an end on the side opposite to the first end32aa. The angle formed by a hypothetical line passing through the first end32aaand the central axis of the shaft body21and a hypothetical line passing through the second end32aband the central axis of the shaft body21when viewed in the first direction DR1is set as a fourth angle θ4. The value obtained by subtracting the fourth angle θ4from 360° is equal to or greater than the value obtained by subtracting the first angle θ1from the second angle θ2.

The rib33extends to intersect with the third opening part32awhen viewed in the first direction DR1. An end of the rib33is connected with the inner wall surface of the tubular part31, and the other end is connected with the bottom part32. Accordingly, the bottom part32is supported by the rib33.

The stepping motor40is installed to the case10by using a motor installation plate41. The involute serrations21bare fit with a rotation output part of the stepping motor40. Accordingly, the stepping motor40rotates the shaft body21about the central axis of the shaft body21and rotates the first valve body20about the central axis of the shaft body21. Since the second valve body30is installed to the first valve body20to be not rotatable about the central axis of the shaft part21, together with the rotation about the central axis of the shaft body21, the second valve body30is also rotated about the central axis of the shaft body21.

In the case where the rotational position of the first valve body20about the central axis of the shaft body21is in a first angle region, the first opening part20efaces the opening part101. When the first valve body20is rotated about the central axis of the shaft body21to approach a second angle region, a portion of the first opening part20ecloser to the second end20ebfaces the opening part101. Since the width W1decreases toward the second end20eb, when the first valve body20is rotated about the central axis of the shaft body21in the first angle region to approach the second angle region, the opening area of the first opening part20ewhen viewed from the first water communication port10bdecreases.

In the case where the rotational position of the first valve body20about the central axis of the shaft body21is in the second angle region, the first opening part20edoes not face the opening part101. That is, in the case where the rotational position of the first valve body20about the central axis of the shaft body21is in the second angle region, the opening area of the first opening part20ewhen viewed from the first water communication port10bis maintained at the minimum.

In the case where the rotational position of the first valve body20about the central axis of the shaft body21is in the first angle region, the second opening part20ffaces the opening part10m. When the first valve body20is rotated about the central axis of the shaft body21to approach the second angle region, among portions of the second opening part20fbetween the first end20faand the intermediate position P, a portion closer to the second end20fbfaces the opening part10m. Since the width W2increases toward the intermediate position P, when the first valve body20is rotated about the central axis of the shaft body21in the first angle region to approach the second angle region, the opening area of the second opening part20fwhen viewed from the second water communication port10cincreases until the maximum.

In the case where the rotational position of the first valve body20about the central axis of the shaft body21is in the second angle region, only the portion of the second opening part20fbetween the intermediate position and the second end20fbfaces the opening part10m. Since the width W2is maintained at the maximum between the intermediate position P and the second end20fb, in the case where the rotational position of the first valve body20about the central axis of the shaft body21is in the second angle region, the opening area of the second opening part20fwhen viewed from the second water communication port10cis maintained at the maximum.

In the case where the rotational position of the first valve body20about the central axis of the shaft body21is in the first angle region, the opening area of the third opening part32awhen viewed from the third water communication port10dis maintained at the maximum. That is, in the case where the rotational position of the first valve body20about the central axis of the shaft body21is in the first angle region, the third opening part32aonly overlaps with the opening part10n. When the first valve body20is rotated about the central axis of the shaft body21to move away from the first angle region, the opening area of the third opening part32aof the third water communication port10ddecreases. That is, when the first valve body20is rotated about the central axis of the shaft body21to move away from the first angle region, the overlapping between the bottom part32and the opening part10nincreases.

The angular width of the first angle region is equal to the first angle θ1. The angular width of the first angle region is 180°, for example. The angular width of the second angle region is equal to the difference between the second angle θ2and the first angle θ1. The angular width of the second angle region is 90°, for example. However, the angular width of the first angle region and the angular width of the second angle region are not limited thereto.

The flow rate of water flowing from the first water communication port10bto the third water communication port10dis set as a first flow rate, and the flow rate of water flowing from the second water communication port10cto the third water communication port10dis set as a second flow rate. The value obtained by dividing the first flow rate by the sum of the first flow rate and the second flow rate is set as a mixing ratio. The mixing ratio may decrease linearly by rotating the first valve body20about the central axis of the shaft body21in the first angle region to approach the second angle region. If the slope of the decrease of the mixing ratio does not change significantly as the rotational angle of the first valve body20increases, the mixing ratio is assumed to decrease linearly.

The case10is further formed with a through hole10p(not shown). The through hole10ppenetrates through the case10to be in communication with the third flow path10h. The thermistor50is inserted into the through hole10p. The thermistor50is connected with the controller60. The thermistor50detects the temperature of the water (hot water) flowing through the third flow path10hto output a signal indicating such temperature to the controller60. The controller60adjusts the temperature of the water (hot water) flowing through the third flow path10hby controlling the stepping motor40to change the rotational position of the first valve body20about the central axis of the shaft body21based on the signal output from the thermistor50.

Although an example in which the second flow path10gextends along the second direction DR2is described above, the second flow path10gmay also extend along a direction other than the second direction DR2. For example, the second flow path10gmay also extend along the first direction DR1. In this case, the second flow path10gis connected with the valve chamber10afrom a side opposite to the first flow path10f.

Although an example in which the first valve body20and the second valve body30are different components is described above, the first valve body20and the second valve body30may also be formed integrally.

(Effect of the Valve Device100)

In the following, the effect of the valve device100is described.

FIG.11is a graph illustrating a relationship among a rotational position of the first valve body20about the central axis of the shaft body21, an opening area of the first opening part20ewhen viewed from the first water communication port10b, the opening area of the second opening part20fwhen viewed from the second water communication port10cand the opening area of the third opening part32awhen viewed from the third water communication port10d. As shown inFIG.11, when the first valve body20is rotated about the central axis of the shaft body21in the first angle region to approach the second angle region, the opening area of the first opening part20ewhen viewed from the first water communication port10bdecreases. When the first valve body20is rotated about the central axis of the shaft body21in the first angle region to approach the second angle region, the opening area of the second opening part20fwhen viewed from the second water communication port10cincreases.

FIG.12is a graph illustrating a relationship among the rotational position of the first valve body20about the central axis of the shaft body21, the first flow rate, and the second flow rate. The result of changing the opening area of the first opening part20ewhen viewed from the first water communication port10band the opening area of the second opening20fwhen viewed from the second water communication port10cdescribed above indicates that, as shown inFIG.12, when the first valve body20is rotated about the central axis of the shaft body21in the first angle region to approach the second angle region, the first flow rate decreases, and the second flow rate increases. In this way, in the valve device100, since the mixing ratio can be adjusted by rotating the first valve body about the central axis of the shaft body21in the first angle region, the temperature of the hot water that is supplied can be adjusted.

At the time when the rotational position of the first valve body20about the central axis of the shaft body21is in the second angle region, the opening area of the first opening part20ewhen viewed from the first water communication port10bis maintained at the minimum (maintained at 0). At the time when the rotational position of the first valve body20about the central axis of the shaft body21is in the second angle region, the opening area of the second opening part20fwhen viewed from the second water communication port10cis maintained at the maximum. When the first valve body20is rotated about the central axis of the shaft body21in the first angle region to move away from the first angle region, the opening area of the third opening part32awhen viewed from the third water communication port10ddecreases. In this way, in the valve device100, at the time when the first valve body20is rotated about the central axis of the shaft body21in the second angle region, the second flow rate is adjusted by using the second valve body30. If only the first valve body20is configured to adjust the second flow rate when the first valve body20is rotated in the second angle region, the second flow rate may change significantly at each rotational angle of the first valve body20about the central axis of the shaft body21. This phenomenon is even more significant in the use under a hot water pressure condition. In the valve device100, since the second valve body30is also used to adjust the second flow rate when the first valve body is rotated in the second angle region, the change of the second flow rate at each rotational angle of the first valve body20about the central axis of the shaft body21can be decreased, and the temperature of the hot water that is supplied is adjusted easily.

In the case where the mixing ratio decreases linearly by rotating the first valve body20about the central axis of the shaft body21in the first angle region to approach the second angle region, the temperature of the water (hot water) flowing through the third flow path10hchanges linearly with respect to the angle of the rotation of the first valve body20about the central axis of the shaft body21, so the temperature of the hot water that is supplied is adjusted easily by using the controller60.

(Configuration of the Hot Water Supply Device200)

In the following, the configuration of the hot water supply device200is described.

FIG.13is a schematic view of the hot water supply device200. As shown inFIG.13, the hot water supply device200has the valve device100, a pipe71, a pipe72, a pipe73, a pipe74, a heat exchanger80, and a burner81. An end of the pipe71is connected with the tap water pipe, and the other end of the pipe71is connected with the first water communication port10b. An end of the pipe72is connected with the pipe71, and the other end of the pipe72is connected with the heat exchanger80. An end of the pipe73is connected with the heat exchanger80, and the other end of the pipe73is connected with the second water communication port10c. An end of the pipe74is connected with the third water communication port10d.

Water is supplied to the first water communication port10bvia the pipe71. Water is supplied to the heat exchanger80via the pipe71and the pipe72. The water supplied to the heat exchanger80is heated by performing heat exchange with the combustion gas generated in the burner81. Water (hot water) passing through the heat exchanger80to be heated is supplied to the second water communication port10cvia the pipe73. In the valve device100, the mixing ratio is changed by adjusting the rotational position of the first valve body20about the central axis of the shaft body21in the first angle region, and the temperature of the water (hot water) flowing from the third communication port10dtoward the pipe74is adjusted.

Due to the upper limit of the heating capability in the heat exchanger80, the temperature of the water (hot water) flowing from the third water communication port10dto the pipe74may not be increased to the desired temperature even if the mixing ratio is set to the maximum. In such case, by adjusting the rotational position of the first valve body20about the central axis of the shaft body21in the second angle region, the temperature of the water (hot water) flowing from the third communication port10dtoward the pipe74is adjusted.

In the above, an example in which the valve device100is used as a mixing valve for mixing low-temperature water and high-temperature water is shown. However, the application of the valve device100is not limited thereto. For example, it may also be that a by-pass pipe is connected with the first water communication port10b, a pipe connected with the heat exchanger is connected with the second water communication port10c, and a pipe connected with the tap water pipe is connected with the third water communication port10d. In such case, the valve device100may serve as a distribution valve and a flow rate adjustment valve on the water inlet side.

Although the embodiment of the invention has been described as above, it is also possible to modify the above embodiment in various ways. Further, the scope of the present invention is not limited to the above embodiments. The scope of the present invention is indicated by the claims, and is intended to include all changes within the meaning and scope equivalent to the claims.