JP3289122B2 - Drainage device for hot water mixer tap - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water drainage device for a hot water mixer tap, and more particularly to a water drain device mounted on a water faucet main body to drain water from the inside of the hot water mixer tap in the immediate vicinity thereof. Things.

[0002]

2. Description of the Related Art In order to prevent breakage of a hot-water mixer tap or the like which is used in a cold region, in order to prevent freezing of the water staying inside in a severe cold condition, the hot-water mixer tap or the like is prevented. It is common to provide a so-called water drainage device in a hot and cold water mixing tap. In this case, since the structure of the entire hot and cold water mixing tap is complicated, it is difficult to drain all the water retained in the hot water chamber and the water chamber by only one water draining device. For example, two are provided on the lower surface of the faucet body and the like to be disposed on the hot water room side and the water room side, respectively.

[0003] Such a conventional water draining device is provided with an operation part at the outer end thereof for human operation by a finger, and by operating this operation part from outside the hot water mixing tap, a predetermined drainage is performed. Is performed. And
Such a water draining device is generally formed of a metal material such as brass for the purpose of facilitating attachment to the hot / water mixing tap itself and preventing rust. It is easy to convey.

[0004] By the way, the hot and cold water mixing tap provided with the above-mentioned water draining device is installed in a bathroom or a kitchen.
In order to prevent freezing in the winter, for example, after the final use at night or the like, the operation unit of the water removal device is pinched and operated by a finger to drain water therein.
The operating unit may have become hot due to the use of hot water. If the operating unit is hot, it cannot be picked up.Therefore, it is necessary to wait until the temperature reaches a level where it can be picked up, or to cool it with water, and the conventional drainage device is inconvenient. It had become something.

[0005] That is, the conventional water draining device may also individually drain water from the hot water chamber 12 and the water chamber 13 formed in the water faucet body 10 as shown in FIG. 6, for example. In particular, the water draining device on the side of the hot water chamber 12 is always in contact with the hot water in the hot water chamber 12, and the operating part 23 of the water draining device is also heated to the same high temperature as the hot water temperature by the hot water. It was what was. Therefore, even if the hot water in the hot water chamber 12 is to be drained by the water draining device after the use of the hot and cold water mixing tap, the operation part 23 is hot and cannot be pinched with the fingers.

Therefore, the inventors of the present invention have proposed a method for removing water in such a water draining device so that the operating portion of the water draining device is always at a temperature at which the operating portion of the water draining device is pinched by a finger. As a result of various studies on what to do, not only hot water but also low-temperature water is always supplied into the hot-water mixing tap provided with this type of drainage device, and it is good to use this. He noticed that it produced results and completed the present invention.

[0007]

SUMMARY OF THE INVENTION The present invention has been made on the basis of the above circumstances, and an object of the present invention is to prevent the operating section of the water draining device from being heated. .

That is, an object of the present invention according to each claim is to provide a structure in which a part is in contact with water in a water chamber so that the water is cooled to prevent the operation portion from becoming high temperature. Draining device that can
It is to provide by a simple structure.

[0009]

Means for Solving the Problems In order to solve the above problems, means according to the first aspect of the present invention will be described with reference numerals used in the embodiment. A hot water chamber 12 and a water chamber 13 partitioned by a partition 11 therein, and at least a water draining device 20a or 20b for discharging hot water in the hot water chamber 12 to the outside,
In the hot / water mixer tap 100 in which the operation unit 23 of the water removal device 20a or 20b is projected from the outer surface of the faucet main body 10, a water chamber is provided between the operation unit 23 and the water chamber 12 of the water removal device 20a or 20b. 13 is a drainage device 100 "characterized in that a part of the drainage device 20a or 20b is exposed in the water chamber 13 with a part of the drainage device 13 interposed therebetween.

That is, the drainage device 20a or 20b according to the first aspect of the present invention is based on the premise that the invention according to the second or third aspect described below is included, and is a part of the drainage device 20a or 20b. Is exposed in the water chamber 13 on the faucet main body 10 side, thereby cooling the entire draining device 20a or 20b so that the operating section 23 does not become hot.

In the first embodiment, a part of the drainage device 20a or 20b corresponds to a mounting joint 24 for mounting the drainage plug 21 to the faucet body 10 in an embodiment described later. Although not shown, the water faucet 21 is formed integrally with the faucet main body 10.
Is a part of the drainage device 20a or 20b referred to herein.

[0012] In order to solve the above-mentioned problems, a means adopted by the invention according to claim 2 is the same as that of claim 1.
0a, "a drain passage 22 penetrating the drainage device 20a toward the inside of the hot water chamber 12 and outside the faucet main body 10 and having a valve port 22a in the middle thereof is formed.
A drain plug 21 having a valve body 21a for opening and closing the valve port 22a is provided so as to be able to advance and retreat. "

That is, in the water draining device 20a according to the second aspect, as in an embodiment to be described later, the mounting joint 24 for mounting the water drain plug 21 to the water tap main body 10, or the water drain main body 10 The discharge passage 2 is formed substantially at the center of a cylindrical body or the like that is formed integrally with
2 is formed. And this discharge path 22
It has a valve port 22a that penetrates into the hot water chamber 12 and the outside of the faucet main body 10, and has a valve port 22a opened and closed by a valve body 21a on the drain tap 21 side in the middle thereof.
When the mounting joint 24 or the tubular body on the faucet main body 10 side surrounding the water 2 contacts the water in the water chamber 13, the entire water draining device 20 a is cooled. Is to prevent the temperature from becoming high.

[0014] Further, according to a third aspect of the present invention, the drainage device 20b of the first aspect is described as follows.
A communication hole 14 between the hot water chamber 12 and the water chamber 13 is formed at the same time, and a water drainage plug 21 constituting the water draining device 20b is
A valve 21a for opening and closing the communication hole 14 and a connecting part 21b integral with the valve 21a and always exposed in the water chamber 13 are provided.
When the hot water is removed from the water chamber 13 at least,
To be discharged through the ".

That is, the drainage device 20a according to the third aspect is a communication hole 1 formed in the partition wall 11 constituting the hot and cold water mixing tap 100 and communicating the hot water chamber 12 and the water chamber 13.
4, a drain plug 2 provided so as to be able to advance and retreat with respect to the partition 11.
The first valve body 21a is inserted, and the valve body 21a is connected to the operation unit 23 by the connecting part 21b. As a result, the connecting part 21b is always connected to the water in the water chamber 13. The operation unit 23 integrated with the drain plug 21 is kept out of contact with the water drain plug 21 so as not to be heated.

[0016]

The operation of the invention according to each of the above-described embodiments will be described.
0a or 20b is substantially included in the invention according to claim 1, and since the operation of the invention of claim 1 often has both of them in common, the drainage device of claim 2 will be described below. 20a and the drainage device 20b of claim 3
The operation will be mainly described.

Further, the draining device 20a or 20b
Since the operation of the hot and cold water mixing tap 100 to which is attached is common to the respective inventions, the common operation will be described first before the description of the operation of each invention.

First, in the hot and cold water mixing tap 100,
The inside of the faucet body 10 is partitioned by a partition 11 into a hot water chamber 12 and a water chamber 13, and hot water is supplied to the hot water chamber 12 from a water heater such as a boiler or various water heaters. Water is supplied from a water supply device such as a water supply.
The supplied hot water and water are mixed in the mixing chamber 16 shown in FIG. 2, and the mixing chamber 16 is set in accordance with the set temperature of the temperature sensing element 40 disposed in the mixing chamber 16.
By changing the respective amounts of hot water and water to be supplied into the inside, the hot water mixer tap 100 can appropriately change the temperature of the hot water discharged from the faucet or the shower port.

The temperature of the hot water to be discharged is set by turning an adjustment handle 41 provided on the right side in FIG. 1 and the hot water is discharged from a faucet or a shower port. The selection is made by turning a switching handle 51 provided in the center of FIG.

Of course, in this hot / water mixer tap 100, when water is drained by operating the water draining device 20a or 20b described below, the water stop screws provided on the water side socket 32 and the hot side socket 31 are used. It is to be ensured that hot water and water are not supplied into the faucet main body 10 by operating them.

(Regarding the water draining device 20a according to the second aspect) In this water draining device 20a, as shown in FIG. 4, a discharge passage 22 penetrating substantially at the center thereof is formed. The inner end of 22 is open into the hot water chamber 12 of the hot and cold water mixing tap 100, while the outer end of the discharge passage 22 is open outside the water tap main body 10 of the hot and cold water mixing tap 100. As shown in (b) of FIG. 4, when the drain plug 21 in the discharge passage 22 is open, the hot water in the hot water chamber 12 is discharged to the outside of the water tap main body 10. It becomes. A drain plug 21 is provided in the discharge passage 22 so as to be able to advance and retreat.
When the second valve port 22a is closed, the hot water in the hot water chamber 12 is not discharged out of the faucet main body 10, as shown in FIG.

In the embodiment described below, as shown in FIG. 4, the discharge passage 22 is formed substantially at the center of a mounting joint 24 for mounting the drain plug 21 to the faucet body 10. A part of the mounting joint 24 is
It is exposed inside. Accordingly, since the mounting joint 24 is exposed in the water chamber 13 and is always in contact with the water in the water chamber 13, the drain plug 21 therein is cooled through the mounting joint 24, and The operation part 23 integrated with the puller 21 is also cooled.

That is, in the water draining device 20a according to the second aspect, the drainage is discharged to substantially the center of the mounting joint 24 or the cylindrical body integrally formed with the water faucet main body 10 and housing the water drainage faucet 21. The path 22 is formed. Then, when the mounting joint 24 or the cylinder on the faucet main body 10 that constitutes the periphery of the discharge path 22 comes into contact with the water in the water chamber 13, the drainage device 2
As a result, the entire drain 0a is cooled, and as a result, the water draining device 20a according to the second aspect is configured so that the operating section 23 does not become hot.

When the hot water in the hot water chamber 12 is discharged, heat is applied to the mounting joint 24 and the like by passing the hot water through the discharge path 22. This means that the hot water is discharged. There is no hindrance because the operation of the operation unit 23 has been performed and the amount of hot water remaining in the hot water chamber 12 is small.

From the above, the drainage device 20 of the present invention
In a, the operating section 23 is not always heated to a high temperature, and a person who intends to operate the operating section 23 can operate the knob without any problem.

(Draining device 20b according to claim 3) In this draining device 20b, as shown in FIG. 5, a communication hole 14 is formed in a part of the partition 11 separating the hot water chamber 12 from the water chamber 13. As shown in FIG. 5 (b), the valve 21a of the drain plug 21 is formed in the communication hole 14 as shown in FIG.
Is not inserted in a watertight manner, the hot water in the hot water chamber 12 can flow into the water chamber 13 through the communication hole 14, and eventually the space in the mounting joint 24 and the drainage of the drain plug 21 It is discharged to the outside through the passage 21c. As shown in FIG. 5A, when the valve 21a formed at the upper end of the drain plug 21 is inserted into the communication hole 14 in a liquid-tight manner, the hot water chamber 12 and the water chamber The communication with the water chamber 13 is cut off, and the hot water in the hot water chamber 12 is not discharged into or out of the water chamber 13.

The valve 21a for opening and closing the communication hole 14 will now be described.
Is integrated with the drain plug 21 via a connecting portion 21b. In the connecting portion 21b, at least the valve body 21a closes the communication hole 14 as shown in FIG. In this case, since it is exposed in the water chamber 13 and is in contact with the water therein, it is cooled. Further, since the operating portion 23 is integrated with the connecting portion 21b, the operating portion 23 is also cooled, and as a result, the operating portion 23 is not heated to a high temperature by the hot water in the hot water chamber 12. There is no.

Of course, when the hot water in the hot water chamber 12 is drained by the water draining device 20b, the hot water adds heat to the valve body 21a and the connecting portion 21b.
As in the case of the drainage device 20a, no adverse effect is caused.

As described above, the drainage device 20 of the present invention
Also in b, the operating section 23 does not always become hot, and a person who intends to operate the operating section 23 can operate the knob without any problem.

As described above, according to the water draining device 20b according to the third aspect, when the water drain plug 21 is in the open state, the hot water in the hot water chamber 12 and the water in the water chamber 13 are simultaneously discharged. Even if only one of them is provided in the faucet main body 10 of the hot and cold water mixing tap 100, the water in the hot water chamber 12 and the water chamber 13 can be drained.

[0031]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the inventions according to the respective claims will be described with reference to the embodiments shown in the drawings.
Since the invention substantially includes the invention according to
A description will be given of the drainage device 20a according to the second aspect and the drainage device 20b according to the third aspect.
In addition, the water draining devices 20a and 20b are
Since the water / water mixer tap 100 is a common premise of the drainage devices 20a and 20b, the description of the water / water mixer tap 100 will be given first as a common matter.

(Regarding Hot Water Mixing Tap 100) As shown in FIGS. 1 to 3, the hot water mixing tap 100 is formed by partitioning the inside of the water tap main body 10 by a partition 11.
2, water chamber 13, and mixing chamber 1 located on the downstream side of these
The hot water supply such as a boiler and a tap are provided to the hot water chamber 12 and the water chamber 13 through the hot water side socket 31 and the water side socket 32, respectively, as shown in FIG. Are connected respectively.
In the hot and cold water mixing tap 100 of the present embodiment, as shown in FIG.
To prevent direct contact by humans to the hot water side socket 31 heated by the hot water flowing inside.

The hot and cold water mixing tap 100 is designed so that the temperature of hot and cold water discharged from a faucet or the like can be freely set. The body 40. The temperature sensing element 40 is configured such that the heat sensing portion is exposed in the mixing chamber 16, and the amount of protrusion of the actuator can be changed according to the temperature of the hot water in the mixing chamber 16. Thereby, the hot water room 12
And the amount of hot water flowing into the water chamber 13 is adjusted. The temperature sensing element 40 can set the temperature of the hot water discharged from the faucet or the like in advance by defining the amount of protrusion of the actuator. The temperature setting is performed by the right side in FIG. This is the adjustment handle 41 seen in FIG.

In the hot and cold water mixing tap 100,
The hot and cold water adjusted to a predetermined temperature in the mixing chamber 16 is
2 or the shower connection port 53, and a switching valve 50 for that purpose is provided substantially at the center of the faucet main body 10, as shown in FIG. The faucet main body 10 is configured to discharge hot water from a faucet 52 or from a shower connected to a shower connection port 53 by operating a switching handle 51 provided on the front side of the hot water mixer tap 100. You can choose.

(Regarding the water draining device 20a according to the second aspect) As shown in FIG. 4, the water draining device 20a has a mounting joint 24 which is screwed to the faucet body 10 in a liquid-tight manner.
A drain passage 22 having a valve port 22a formed substantially at the center thereof and having a valve port 22a, a drain plug 21 screwed into the discharge passage 22, and an outer end of the drain plug 21 integrated therewith. The operation unit 23 is attached to the faucet main body 10 so that the operation unit 23 projects from the lower surface of the hot and cold water mixing tap 100 as shown in FIG.

Further, in the faucet main body 10 to which the water draining device 20a is applied, as shown in FIG. 4, the hot water located substantially at the center of the part where the water draining device 20a is to be attached. A water chamber 13 is formed around the chamber 12 through a partition 11, and an insertion hole 15 is formed in the partition 11 so that the inner end of the mounting joint 24 on the side of the draining device 20 a is fitted in a liquid-tight manner. It has been done.

As described above, the discharge passage 22 provided substantially at the center of the mounting joint 24 has its inner end side opened into the hot water chamber 12.
The outer end can be opened toward the outside. Therefore, the discharge passage 22 penetrates through the water chamber 13 through the attachment joint 24 located on the outer periphery thereof, and discharges the hot water in the hot water chamber 12 to the outside. is there.

As described above, the drain plug 21 is provided in the discharge path 22 so as to be able to advance and retreat.
A part of the drain plug 21 is screwed to the outer end of the mounting joint 24, and the operating part 2 is attached to the outer end of the drain plug 21.
When the operation unit 23 is pinched and rotated by a finger, the drain plug 21
2 to advance and retreat. At the inner end (the upper end in FIG. 4) of the drain plug 21, a valve 21 a capable of closing a valve port 22 a of the discharge passage 22 is integrally formed. By closing the valve port 22a as shown in FIG. 4A, the discharge of hot water from the hot water chamber 12 is prevented. Of course, if the entire drainage plug 21 is moved downward in the figure by operating the operation unit 23, FIG.
As shown in (b) of FIG.
Therefore, the hot water in the hot water chamber 12 can enter the discharge path 22.

Further, as shown in FIG. 4, the lower part of the drain plug 21 is opened to the side at the upper end side, and is drawn through the center of the drain plug 21 as shown in FIG. A drain passage 21c opening at the lower end is formed. Therefore, when the drain plug 21 is brought into the state shown in FIG. 4B by the operation of the operation unit 23, the drain passage 21c communicates with the drain passage 22 at the opening on the upper end side. Therefore, the hot water in the hot water chamber 12 of the faucet main body 10 is discharged to the outside through the discharge passage 22 through the drain passage 21c.

In the water draining device 20a configured as described above, a part of the mounting joint 24 that partitions the discharge passage 22 from the other is always in the water chamber 13 regardless of the state of the water drain plug 21. Therefore, a part of the mounting joint 24 is always cooled by the water filled in the water chamber 13 before drainage is performed.

(Regarding the water draining device 20b according to claim 3) In this water draining device 20b, as shown in FIG. 5, the hot water chamber 12 and the water chamber 13 of the faucet main body 10 are adjacent to each other via the partition wall 11. Is applied to the part with
0, a water drainage plug 21 which is mounted in a through hole formed at the center of the mounting joint 24, and which can move forward and backward with respect to the mounting joint 24. And an operation unit 23 integrally formed at the end.

The mounting joint 24 of the water draining device 20b has an inner end of a through hole formed at the center of the mounting joint 24 and opens into the water chamber 13. The mounting joint 24 has a shape that is easily screwed to the outer wall of the faucet main body 10, for example. There are things. Of course, the outer end of the through hole formed at the center of the mounting joint 24 is open to the outside of the faucet main body 10, and a valve port 22a is formed therein. Puller 2
1, which is opened and closed by a shoulder located below the valve body 21a, which will be described below.

As shown in FIG. 5, the drain plug 21 has a valve body 21a at its upper end in the figure.
Is a liquid-tight fit in a communication hole 14 formed in a part of the partition wall 11 that separates the hot water chamber 12 from the water chamber 13 and whose axis coincides with that of the mounting joint 24. The valve body 21a is integrated with the drain plug 21 via a connecting portion 21b located at the lower end in the figure, and the connecting portion 21b is installed in the water chamber 13 of the faucet main body 10. There is something to be exposed.

Further, the connecting portion 21b of the drain plug 21
3. The draining device 20a according to claim 2,
As in the case of the drain plug 21, a drain passage 21 c that opens at the upper end into the through hole of the mounting joint 24 and opens downward to the outside is formed. When the lower position is reached as shown in FIG. 5B by the operation of 23, the inside of the water chamber 13 is communicated with the outside.

That is, in the water draining device 20b, as shown in FIG. 5A, when the water drain plug 21 is closed by the operation section 23, the valve 21 is closed.
a is fitted in the communication hole 14 of the partition wall 11 in a liquid-tight manner, thereby blocking the communication between the hot water chamber 12 and the water chamber 13 by the communication hole 14, and the shoulder of the drain plug 21 is connected to the inside of the mounting joint 24. The through hole in the mounting joint 24 is closed by contacting the valve port 22a provided in the mounting joint 24. On the contrary,
By operating the operation unit 23 to open the drain plug 21,
As shown in FIG. 5B, the communication hole 14 on the partition wall 11 side
21a, the shoulder of the drain plug 21 is removed from the valve port 22a in the mounting joint 24, and thereby the drain passage 21c formed in the drain plug 21 and the side of the faucet main body 10 are removed. The hot water chamber 12 and the water chamber 13 communicate with each other, and the hot water in the hot water chamber 12 and the water chamber 13 is discharged from the lower end of the drain passage 21c.

As described above, the drainage device 20b according to the third aspect of the present invention has
Since the hot and cold water in the hot water chamber 12 and the water chamber 13 can be simultaneously discharged, the hot water main body 10
, Water can be drained from the hot water chamber 12 and the water chamber 13.

[0047]

As described in detail above, according to the first aspect of the present invention, as described in each of the above embodiments, "the hot water chamber 12 and the water chamber partitioned by the partition 11 inside the faucet main body 10". 13 having a water draining device 20a or 20b for discharging at least hot water in the hot water chamber 12 to the outside, and an operating portion 23 of the water draining device 20a or 20b protruding from the outer surface of the faucet main body 10. In the mixing tap 100, the operation unit 23 of the water removal device 20a or 20b
A part of the water chamber 13 is interposed between the water chamber 13 and the water chamber 12, and a part of the water draining device 20a or 20b is exposed in the water chamber 13. " By providing a simple configuration, a water draining device that can be configured to partially touch the water in the water chamber, thereby preventing the operation unit from being heated to a high temperature by being cooled by the water. You can do it.

According to the second aspect of the present invention, the water draining device 20a according to the first aspect of the present invention penetrates the water draining device 20a toward the inside of the hot water chamber 12 and the outside of the faucet main body 10. A discharge passage 22 having a valve port 22a is formed on the way, and a drain plug 21 having a valve 21a for opening and closing the valve port 22a is provided in the discharge passage 22 so as to be able to advance and retreat. Therefore, the above claim 1
In addition to achieving the same effects as the invention according to the first aspect, the hot water in the hot water chamber 12 can be discharged directly and in a short time.

Further, the drainage device 20b according to claim 3
According to this, the communication hole 1 between the hot water chamber 12 and the water chamber 13 is formed in the partition 11.
4 and the drain plug 21 constituting the drain device 20b is connected to the valve body 21a for opening and closing the communication hole 14.
And the connecting part 2 which is integral with the connecting part and is always exposed in the water chamber 13.
1b, and when the valve body of the drain plug 21 comes off from the communication hole 14, at least the hot water in the hot water chamber 12 is discharged through the water chamber 13. Accordingly, the same effect as the invention according to claim 1 can be exhibited, and the water draining device 20b itself can be easily attached to the faucet main body 10.

Furthermore, the drainage device 2 according to claim 3
According to 0b, when the drain plug 21 is in the open state,
The hot water in the hot water chamber 12 and the water chamber 13 can be drained at the same time. Even if only one of them is provided in the faucet main body 10 of the hot / water mixing tap 100, the water in the hot water chamber 12 and the water chamber 13 is drained simultaneously. Is what you can do.

[Brief description of the drawings]

FIG. 1 is a partially cutaway front view of a hot and cold water mixing tap to which a drainage device according to the present invention is applied.

FIG. 2 is a partially broken plan view of the hot and cold water mixing tap.

FIG. 3 is a side sectional view of the hot and cold water mixing tap taken along line 1-1 in FIG. 2;

FIG. 4 is a partially enlarged side sectional view of the drainage device according to claim 2 taken along line 2-2 of FIG. 2, wherein (a) is in a closed state, and (b) is in an open state. , Respectively.

5 is a partially enlarged side sectional view of the drainage device according to claim 3 taken along line 2-2 in FIG. 2, wherein (a) is in a closed state, and (b) is in an open state. , Respectively.

FIG. 6 is a partial side sectional view showing a conventional water draining device.

[Explanation of symbols]

 REFERENCE SIGNS LIST 100 hot water mixer tap 10 faucet main body 11 partition wall 12 hot water chamber 13 water chamber 14 communication hole 15 insertion hole 16 mixing chamber 20 ab / 20 b water draining device 21 water drain plug 21 a valve element 21 b connecting portion 21 c drain passage 22 discharge passage 22 a valve opening 23 Operation part 24 Mounting joint

Continuation of the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) F16K 39/00-51/02 F16K 11/00 F16K 31/00-31/05 F16K 3/00-3/36 F16K 31 / 68 E03C 1/00-1/10

Claims (3)

(57) [Claims] 1. A water faucet having a water chamber and a water chamber partitioned by a partition inside a faucet body, a water drainage device for discharging at least hot water in the water chamber to the outside, and an operation unit of the water drainage device A water / water mixer tap protruding from an outer surface of the faucet main body, wherein a part of the water chamber is interposed between the operation unit and the water chamber of the water draining device, and the water is supplied into the water chamber. A draining device characterized in that a part of the draining device is exposed. 2. A drain passage which penetrates the water draining device toward the inside of the hot water chamber and the outside of the faucet body and has a valve port in the middle thereof, and opens and closes the valve port in the discharge channel. The water draining device according to claim 1, wherein a water drain plug having a valve body is provided so as to be able to advance and retreat. 3. A valve body for forming a communication hole between the hot water chamber and the water chamber in the partition wall, and connecting a drain plug constituting the water draining device with the valve body for opening and closing the communication hole. And a connecting portion that is always exposed in the water chamber, and when the valve body of the drain plug comes off from the communication hole, at least hot water in the water chamber is passed through the water chamber. The drainage device according to claim 1, wherein the water is drained.