JPH06142418A - Device and method for purifying hot water in bathtub - Google Patents

Abstract

PURPOSE:To provide a device and method for purifying hot water in a bathtub where a filter medium is effectively backwashed and which is simple and in expensive. CONSTITUTION:Eight hot water flow pipes, hot water suction and jetting pipes 3, 13 from/to a bathtub 1, tank inflow and outflow pipes 7, 8 from/to a tank filter 6, pump outflow and inflow pipes 10, 11 from/to a circulating pump 9, a pump outflow conduit 12 and a hot water drain pipe 14, are connected to a port switching valve 5. By switching the valve, three hot water circulating passes, that for purification where hot water flows in the forward direction, that for backwash where hot water flows in the reverse direction and that for forward washing where hot water is circulated in the forward direction while discharging to outside the bathtub, are formed and when backwash is finished, the circulation of the forward washing is performed before returning to the purification. Therefore the circulating pass switching is easily performed by the simple and inexpensive switching valve and the backwash of the filter medium is effectively performed and simultaneously by the circulation of the forward washing, when the backwash is returned to the purification, hot water in the bathtub is not contaminated by fouling separated from the filter medium on backwashing to always keep the hot water clean.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bathtub device, and in particular, to properly clean a filtration tank filled with a filter medium such as activated stone or activated carbon to effectively filter dirt in hot water and keep the hot water constantly clean. The present invention relates to a bathtub cleaning device having a backwash function.

[0002]

2. Description of the Related Art Recently, cleaning of bath water by pumping hot water in a bathtub with a circulation pump and forcibly circulating it through a circulation path provided with various types of cleaning treatment equipment and ejecting the purified hot water again into the bathtub The device was developed.

This bath water purifying device includes a circulation pump for circulating the hot water, a pre-filter provided at the hot water inlet of the hot water pipe for filtering large dirt, and the capacity of the filtering material while filtering dirt. A filtration tank filled with a porous granular filter medium for water treatment according to the above, an ozone sterilizer for sterilization, and a cleaning treatment device such as a heater for keeping hot water at an appropriate temperature are provided.

In the filtration tank, dirt is removed by ion exchange, and at the same time, activated stone such as barley stone that elutes and activates minerals, activated carbon that adsorbs and removes dirt, and dirt is adsorbed and adsorbed at the same time. Porous granular materials having various water treatment capacities such as zeolite, which are removed by means of the above method, are filled individually or in combination to form a filtration layer.

Therefore, the filtration tank is, as described above,
Not only the filtration capacity of the filtration layer, but also the water treatment capacity according to the capacity of the filled filter material is effective in cleaning the bath water.

With the development of the cleaning device as described above, it becomes possible to enjoy comfortable bathing with hot water of a suitable temperature at any time for 24 hours without changing the hot water.

When such a cleaning device is continuously operated, the filter medium filled in the filter tank becomes dirty and the filter layer is clogged, the circulating amount of hot water is reduced, and the cleaning ability is deteriorated.

Therefore, when the filter layer is clogged,
Since the filter medium forming the filter layer is not always cheap and cannot be replaced frequently, the filter medium is taken out of the filtration tank and washed.

Further, cleaning the filter medium is troublesome and at the same time not so preferred for dirty work. Therefore, in order to automatically wash the filter medium without removing it from the filter tank, it is necessary to clean the filter layer with hot water. Many so-called backwashing devices for washing the filter medium by flowing in the opposite direction to automatically wash the device have been developed.

[0010]

However, there are two major problems in cleaning the filter medium using the conventional backwashing device: the pipe switching device and the contamination of the bath water immediately after the backwashing.

First, in order to perform backwashing, the flow direction of hot water is reversed to that in the case of cleaning, and two-way switching is performed in order to discharge the washed hot water to the outside of the bathtub through the hot water discharge pipe. Solenoid valves that perform the above must be provided at multiple locations.

However, when a plurality of solenoid valves are provided in the hot water flow passage, the control device for switching the pipeline is complicated and expensive, and at the same time, the solenoid valve is liable to be damaged due to dirt in the hot water. However, if a plurality of these are deployed, the device will be very prone to failure.

Next, when backwashing is performed, most of the dirt attached to the filter material is separated from the filter material and discharged through the hot water discharge pipe, but a part of the dirt left after being separated from the filter material but not discharged is left. Immediately after the part finishes backwashing and starts cleaning, it may flow into the bathtub and pollute the hot water in the bathtub.

The present invention solves the above-mentioned drawbacks of the prior art, utilizes a simple and inexpensive device that does not cause a failure, and can effectively perform backwashing, and even in the cleaning immediately after backwashing, the bathtub can be cleaned. It is an object of the present invention to provide a bathtub hot water cleaning device and a cleaning method in which dirt does not flow into the bathtub.

[0015]

That is, according to the present invention, the hot water in the bathtub is pumped up by a circulation pump through a hot water suction pipe, the dirt is filtered by a filtration tank, and then returned to the bathtub again through a hot water pipe to continuously supply hot water in the bathtub. In a bathtub hot water purification device for keeping clean, a suction pipe and a spout pipe for sucking and ejecting hot water into and from a bathtub, a tank inflow pipe and a tank outflow pipe for flowing hot water into and out of a filtration tank, and a circulation pump Eight hot water distribution pipes: a pump inflow pipe and a pump outflow pipe for flowing hot water into and out of the bath, and a hot water discharge pipe for discharging hot water out of the bathtub, and a pump outflow branch pipe branched from the pump outflow pipe Is a bathtub hot water purifying device, which is provided with an 8-port switching valve for connecting to each other. The switching valve is provided with eight connection ports for each of the eight hot water distribution pipes including a pump outlet branch pipe on the upper surface. The bottom surface is open A cylindrical valve case and a plurality of hot water flow grooves for forming a hot water flow passage which is rotatably fitted in the valve case and is connected to the connection port of the valve case and connects adjacent connection ports to each other. And a valve body provided with a drive shaft and a valve case having a bearing hole for rotatably supporting the drive shaft of the valve body The bath water purifying device characterized by comprising a lid, the switching valve, the connection port of the hot water flow pipe and the hot water passageway are selectively coupled with the rotation of the valve body, A hot water circulation pipe, a filtration tank, a circulation pump, and a hot water pipe in this order to purify the hot water with a filter medium. The hot water circulating in the opposite direction to wash the filter media, and the hot water suction pipe, the filtration tank, the circulation pump, and the exhaust The above-mentioned bath water is characterized in that the pipes are switched so as to form three hot water circulation passages of a forward washing circulation passage in which the hot water is discharged from the bath in the order of the pipes and is circulated in the forward direction to wash the filter medium. Is a cleaning device,
After the hot water is circulated in the reverse direction to wash the dirt on the filter medium, the hot water is discharged from the drain pipe to circulate in the forward direction to wash the filter medium. The method for cleaning hot water in a bathtub is characterized by switching to a cleaning circuit after the cleaning.

[0016]

The present invention is constructed as described above, and by properly rotating the valve body of the switching valve, the circulation path of hot water is cleaned in the forward direction, backwashed in the reverse direction, and the hot water is discharged to the outside of the bathtub. However, it is possible to easily switch to the three types of forward washing in which the circulation is performed in the forward direction.

Moreover, since the structure of the switching valve is simple, it is easy to manufacture and inexpensive, and there is almost no risk of failure due to dirt and the valve is provided with a connection port for each hot water distribution pipe. At the same time, since the hot water circulation groove for forming the hot water flow passage for connecting the adjacent connection ports to each other is provided, the piping becomes extremely simple.

Before the backwashing is completed and the pipe line is switched to the cleaning, the hot water is discharged to the outside of the bath and circulated in the forward direction to wash the filter medium. Dirt remaining in the tank without being discharged from the hot water discharge pipe is washed by this circulation and all the hot water containing dirt is thrown out of the bathtub. Since it will adhere to the filter media again, there is no concern that dirt will enter the bath immediately after cleaning is started.

[0019]

Embodiments of the present invention will now be described with reference to the drawings.

FIG. 1 is a piping diagram showing the structure of the apparatus of the present invention, in which 1 is a bathtub, 2 is hot water, 3 is a hot water suction pipe for sucking hot water 2 from the bathtub, 4 is hot water in the direction opposite to the hot water pipe. Check valve to prevent the flow of water, 5 is an 8-port switching valve with independent connection ports for 8 hot water distribution pipes including a pump outlet branch pipe, and 6 is a filter filled with a filter medium such as activated carbon or barley stone. Tank, 7 is a tank inflow pipe that connects the hot water to the filtration tank 6 and is connected to the tank side method, 8 is a tank outflow pipe that is connected to the bottom of the tank that flows the filtered hot water out of the filtration tank 6, and 9 is the forced hot water. Circulation pump 10 for circulation and circulation pump 9
A pump inflow pipe for inflowing hot water into the pump, 11 a pump outflow pipe for outflowing hot water from the circulation pump 9, and 12 a pump outflow pipe 1
1, a pump outlet branch pipe branched from the middle of 1, a hot water pipe 13 for re-spouting the cleaned hot water into the bathtub 1, and a fresh water pipe 14 for washing the backwash water and the forward wash water outside the bathtub 1. It is a drainage pipe for discharging to.

Eight hot water distribution pipes, which are a hot water suction pipe 3, a tank outflow and outflow pipes 7 and 8, a pump outflow and outflow pipes 10 and 11, a pump outflow branch pipe 12, a spout pipe 13, and a drainage pipe 14, which form a circulation path for hot water. 1 is connected to the eight connection ports of the switching valve 5 as shown in FIG.

Of course, the present embodiment shows only the basic structure, and in the actual device, other devices such as a heater for heating hot water and an ozone sterilizer for sterilization are further provided in the hot water circulation path. It has been deployed.

Next, the state in which three hot water circulation paths of cleaning, backwashing, and normal washing are formed will be described.

FIG. 2 shows the case where the hot water is cleaned, in which case the switching valve 5 is switched so that the adjacent connection ports of the hot water flow pipe are connected via the hot water passage as shown by the dotted line. ing.

The hot water suction pipe 3 and the tank inflow pipe 7 are the hot water flow passage 1
5, the tank outflow pipe 8 and the pump inflow pipe 10 are the hot water flow passage 16, and the pump outflow pipe 11 and the hot water discharge pipe 12 are the hot water flow passage 1
7 are connected to each other, and a pump outlet branch pipe 12 and a hot water discharge pipe 1
3 directions are closed, and the hot water is absorbed by the hot water pipe 3 as shown by the arrow.
A hot water circulation path is formed in the forward direction from the top to the bottom of the spout tube 12 that flows from the top to the bottom in the filtration tank 6.

When the circulation pump 9 is operated in this state, the hot water 2 in the bathtub 1 is sucked up from the hot water pipe 3 and the flow of the hot water is in the forward direction, so the check valve 4 is opened and the hot water flow of the switching valve 5 is made. It flows into the filtration tank 6 from above via the passage 15 and the tank inflow pipe 7.

The hot water that has entered the filtration tank 6 flows downward while the dirt is filtered by the filled filter material and at the same time the activation stones are activated. 5 hot water flow passage 17 and pump inflow pipe 1
After entering the circulation pump 9 through 0, it flows out from the pump outflow pipe 10, is returned again from the spout pipe 12 to the bathtub 1 through the hot water passage 17 of the switching valve 5, and the hot water is purified by this circulation.

Next, the hot water is cleaned for a predetermined period of time, and the filter material filled in the filtration tank 6 becomes dirty and clogged, and the cleaning effect is lost, so backwashing is performed to remove this dirt. The case will be described with reference to FIG.

In this case, the switching valve 5 is switched so that the adjacent connection ports of the hot water flow pipe are connected to each other via the hot water flow passage shown by the dotted line.

The hot water suction pipe 3 and the pump inflow pipe 10 are a hot water flow passage 18, the pump outflow pipe 11 and the tank outflow pipe 8 are a hot water flow passage 19, and the tank inflow pipe 7 and the hot water discharge pipe 14 are hot water flow passages. Road 2
0 are connected to each other and the direction of the hot water discharge pipe 13 is opened, and at the same time, the directions of the spouted water pipe 12 and the pump outflow branch pipe 12 are closed, and the hot water flows from the hot water suction pipe 3 to the filtration tank 6 from the bottom to the top as shown by the arrow. After flowing, it forms a circulation path for hot water in the opposite direction toward the hot water discharge pipe 14.

When the circulation pump 9 is operated in this state, the hot water 2 in the bathtub 1 is sucked up from the hot water pipe 3 and the flow of the hot water is in the forward direction, so the check valve 4 is opened and the switching valve 5 is opened. Circulation pump 9 through hot water passage 18 and pump inflow pipe 10
to go into.

The hot water that has entered the circulation pump 9 is the pump outflow pipe 1.
1. After passing through the hot water passage 19 of the switching valve 5 and the tank outflow pipe 8, it enters the filtration tank 6, flows through the inside of the filtration tank 6 from the bottom to the top, and backwashes to remove dirt attached to the filter medium.

The hot water obtained by backwashing the filtration tank 6 is discharged from the hot water discharge pipe 14 through the tank inflow pipe 7 and the hot water flow passage 20 of the switching valve 5, and if this backwashing is continued for a predetermined time, the hot water is filled in the filtration tank 6. The filter material is not clogged, and the hot water can be purified again by the forward flow.

FIG. 4 shows a case of a forward washing circulation path in which hot water is discharged to the outside of the bath 1 and circulates in the forward direction. In this case, the switching valve 5 connects the adjacent connection ports of the hot water flow pipes to each other. It is switched to be connected via a hot water passage as shown by a dotted line.

The hot water suction pipe 3 and the tuck inflow pipe 7 are formed by the hot water flow passage 15.
Then, the tank outflow pipe 8 and the pump inflow pipe 10 are connected to the hot water flow passage 1
6 is connected in the same manner as in the case of cleaning, the pump outflow branch pipe 12 and the hot water discharge pipe 14 are connected by the hot water flow passage 21, the pump outflow pipe 11 and the hot water discharge pipe 13 are closed, and the hot water is indicated by an arrow. As shown in the drawing, a forward-wash circulation circuit for pumping hot water from the bath tub 1 in a forward direction from the top to the bottom in the filtration tank 6 and then discharging the hot water from the hot water discharge pipe to circulate the hot water outside the bath in the forward direction. To form.

When the circulation pump 9 is operated in this state,
The hot water 2 in the bathtub 1 is sucked up from the hot water suction pipe 3 and the switching valve 5
Filter tank 6 through hot water flow passage 15 and tank inflow pipe 7
to go into.

The hot water in the filtration tank 6 flows in a forward direction from the top to the bottom in the tank, and a part of the dirt left in the tank without being discharged although being separated from the filter material during backwashing. After the filter material is washed while being reattached to the filter material, it flows out from the tank outflow pipe 7, enters the circulation pump 9 through the hot water flow passage 16 of the switching valve 5 and the pump inflow pipe 10.

The hot water that has entered the circulation pump 9 and which has been contaminated by normal washing does not flow out from the pump outflow pipe 11 and return from the spout pipe 13 to the bath 1 as in the case of cleaning, but rather the pump outflow branch pipe. 12, the hot water flow passage 21 of the switching valve 5
After that, it is discharged from the hot water discharge pipe 14 to the outside of the bathtub 1.

When the circulation of the normal washing is continued for a predetermined time, some dirt left in the filter tank 6 by the back washing but not discharged from the hot water discharge pipe 14 and remaining in the tank is again attached to the filter material. At the same time, since all the hot water containing dirt is discharged to the outside of the bathtub, no dirt is brought into the bathtub 1 even after returning to the circulation path of the cleaning process.

Next, the structure of the switching valve 5 for switching the circulation path of the hot water as described above will be described.

FIG. 5 is an exploded perspective view of the switching valve 5.
Is a cylindrical valve case with an open bottom surface,
Eight connection ports 23 to which each of the hot water distribution pipes of the book are individually connected
Numerals 30 are arranged at equal intervals on the circumference of the circle slightly inside the outer circumference.

Reference numeral 31 is a disc-shaped valve body that is rotatably fitted inside the valve case 22, and is located on the surface of the valve body 31 so as to face the connection ports 23 to 30 of the valve case 22. The blind long groove-shaped hot water flow channels 32, 33, and 34 are provided as hot water flow passages that connect the continuous three adjacent connection ports of the four adjacent connection ports to each other. A drive shaft 35 for rotating the valve body 31 projects downward.

Reference numeral 37 is a valve lid, and the valve lid 37 is fitted in the valve case 22 in which the valve body 31 is fitted and has an upper surface opened to close the opening of the lower surface, and a bottom surface for passing the drive shaft 35 of the valve body 31. A bearing hole 37 is provided at the center of the.

Next, a state in which the switching valve 5 having the above-mentioned structure is switched to form a hot water circulation path will be described.

The state in which the switching valve 5 is switched so as to form the circulation path for cleaning the hot water is as shown in FIG. 6 as a top view (a) and a vertical sectional view (b). The connection state of the connection port and the hot water distribution pipe will be described.

The hot water flow pipes are connected to the respective connection ports by the tank inflow pipe 7, the hot water suction pipe 3, the pump inflow pipe 10, the tank outflow pipe 8, the pump outflow pipe 11, the spouted hot water pipe 13, the pump outflow branch pipe 12, and the exhaust pipe. It suffices to connect the hot water pipes 13 to the connection ports in the counterclockwise direction in order, and as shown by the reference numerals of the hot water flow pipes connected to the respective connection ports, for example, the tank inlet pipe 7 is provided at the connection port 23.
However, 24 is the hot water suction pipe 3, 25 is the pump inflow pipe 10,
26 is a tank outflow pipe 8 and 27 is a pump outflow pipe 11.
However, 28 is connected to the molten metal pipe 13, 29 is connected to the pump outflow branch pipe 12, and 30 is connected to the molten metal discharge pipe 14.

When the hot water flow pipes are connected to the respective connection ports for cleaning in this way, the valve body 31 is rotated by the motor 38 via the drive shaft 35 so that the adjacent connection ports 23 and 24 are heated. Circulation grooves 32, 25 and 26 are hot water circulation grooves 33, 2
7 and 28 are aligned with the hot water flow groove 34.

As a result, the hot water flow passage 32 connects the hot water pipe 3 and the tank inflow pipe 7 with the hot water flow passage 15 as shown in FIG. Groove 33
Is a hot water flow passage 16 connecting the tank outflow pipe 8 and the pump inflow pipe 10, and the hot water flow groove 34 is a hot water flow passage 17 connecting the pump outflow pipe 11 and the spout metal pipe 13.

Further, since the adjacent connection ports 29 and 30 are closed so as not to coincide with any of the hot water flow grooves, the hot water of the pump outflow branch pipe 12 and the hot water discharge pipe 14 connected to these connection ports is closed. Since the distribution is cut off, a circulation path for hot water for cleaning is formed as shown in FIG.

Next, the state in which the valve body 31 is rotated to form a hot water circulation path for backwashing will be described with reference to FIG.

In this state, the valve element 31 is located rotated by 45 ° in the clockwise direction from the cleaned state, and the adjacent connection ports 30 and 23 are in the hot water flow groove 32, and 24 and 2.
5 corresponds to the hot water flow groove 33, and 26 and 27 match to the hot water flow groove 34.

As a result, the hot water flow passage 18 connects the hot water suction pipe 3 and the pump inflow pipe 10 with the hot water flow passage 18 as shown by the corresponding hot water flow passage in FIG. Groove 3
Reference numeral 4 forms a hot water flow passage 19 that connects the pump outflow pipe 11 and the tank outflow pipe 8, and the hot water flow groove 32 forms a hot water flow passage 20 that connects the tank inflow pipe 7 and the hot water discharge pipe 14.

Further, since the adjacent connection ports 28 and 29 are closed so as not to coincide with any of the hot water flow grooves, the hot water flow to the pump outflow branch pipe 12 and the hot water pipe 13 is cut off, as shown in FIG. A hot water circulation path for backwashing is formed.

Finally, a state in which a circulation path for normal washing is formed in which hot water is discharged to the outside of the bath and circulated in the forward direction to wash the filter medium will be described with reference to FIG.

In this state, the valve element 31 is located at a position further rotated by 45 ° in the clockwise direction from the backwash state,
Adjacent connection ports 23 and 24 match the hot water flow groove 33, 25 and 26 match the hot water flow groove 34, and 29 and 30.
And are aligned with the hot water distribution groove 32.

As a result, the hot water flow passage 15 connects the hot water suction pipe 3 and the tank inflow pipe 7 with the hot water flow passage 15 as shown in FIG. Groove 34
Forms a hot water flow passage 16 that connects the tank outflow pipe 8 and the pump inflow pipe 10, and the hot water flow groove 32 forms the pump outflow branch pipe 1
A hot water flow passage 21 that connects the hot water discharge pipe 14 and the hot water discharge pipe 14 is formed.

The adjacent connection ports 27 and 28 are closed, and the flow of hot water to the pump outflow pipe 11 and the spout pipe 13 connected to these connection ports is cut off. A wash circuit is formed.

[0058]

The present invention has the above-described structure and operation, and the dirt on the filter medium is automatically removed by backwashing at a predetermined interval, so that the effect is always obtained without spending time and money for maintenance. There is provided a bath water purifying device provided with a filtering device capable of performing effective filtration.

Further, after the backwashing is finished, the hot water is discharged to the outside of the bath while flowing in the forward direction to wash the filter medium, so that the filter medium is circulated. Some of the stains are discharged to the outside of the bath while adhering to the filter medium again, so that the hot water in the bath is not polluted by the remaining stain immediately after restarting the cleaning.

The switching valve for switching the hot water circulation path used in this device has a simple structure and can be manufactured easily at a low cost, and at the same time, the control for switching the piping path is easy and is unlikely to break down during operation. .

Further, since the changeover valve is provided with the hot water flow passage and has the hot water flow passage for connecting the hot water flow pipes to each other, the piping can be simply carried out with a very small number of pipes, so that the device can be manufactured, installed and maintained. Etc. are easy.

[Brief description of drawings]

FIG. 1 is a piping diagram of an embodiment,

[Fig. 2] Circulation path of hot water at the time of cleaning,

[Fig. 3] Hot water circulation during backwashing,

[Fig. 4] Hot water circulation during normal washing

FIG. 5 is an exploded perspective view of a switching valve,

FIG. 6 is a switching switching state of the switching valve,

FIG. 7 is a backwash switching state of the switching valve,

FIG. 8 shows a state in which the switching valve is switched to normal washing.

[Explanation of symbols]

 1 Bathtub 2 Hot water 3 Hot water suction pipe 4 Check valve 5 Switching valve 6 Filtration tank 7 Tank inflow pipe 8 Tank outflow pipe 9 Circulation pump 10 Pump inflow pipe 11 Pump outflow pipe 12 Pump outflow branch pipe 13 Fountain pipe 14 Discharge pipe 15 -21 hot water flow passage 22 valve case 23-30 connection port 31 valve body 32-34 hot water flow groove 35 drive shaft 36 valve lid

Claims (4)

[Claims] 1. Cleaning of bath water for continuously keeping the bath water clean by pumping the hot water in the bathtub with a circulation pump through a hot water pipe, filtering dirt in a filtration tank, and returning it again to the bathtub with a hot water pipe Sucking pipe for sucking and ejecting hot water into and out of a bath, tank inflow pipe and tank outflow pipe for letting hot water into and out of a filtration tank, and pump for letting hot water flow in and out of a circulation pump Inflow pipe and pump outflow pipe, and seven drainage pipes for discharging hot water out of the bathtub,
8 with pump outlet branch pipe branched from pump outlet pipe
An apparatus for cleaning a bathtub hot water, which is provided with an 8-port switching valve connected to a hot water distribution pipe of a book. 2. A switching valve having a cylindrical valve case having eight connection ports for each of the eight hot water flow pipes including a pump outlet branch pipe provided on the upper surface and having an open lower surface, and rotated in the valve case. A valve body provided with a drive shaft, the valve body having a plurality of hot water flow channels for freely forming a hot water flow passage that is connected to a connection port of the valve case and connects adjacent connection ports to each other; 2. The cylindrical valve lid having an open upper surface, which is fitted to close the lower surface opening, in the valve case provided with a bearing hole for rotatably supporting the drive shaft of the body. Cleaner for bath water. 3. The changeover valve selectively connects the connection port of the hot water flow pipe and the hot water flow passage with the rotation of the valve body, and a hot water suction pipe, a filtration tank, a circulation pump, and a hot water pipe in this order. Backwashing circulation in which the hot water circulates in the forward direction and the hot water is cleaned by the filter media. The cleaning circulation path, hot water suction pipe, circulation pump, filtration tank, and hot water discharge pipe circulate in the reverse direction to wash the filter media. The three hot water circulation passages, namely, the hot water washing pipe, the filtration tank, the circulation pump, and the hot water discharge pipe are sequentially circulated in the forward direction while the hot water is discharged to the outside of the bath to wash the filter medium. The bath water cleaning device according to claim 1 or 2, wherein the pipe lines are switched so as to form the bath water. 4. A normal wash circulation in which hot water is circulated in a reverse direction in a backwash circulation path to wash dirt adhering to the filter medium, and then hot water is circulated in the forward direction while draining the hot water to wash the filter medium. A method for cleaning hot water in a bathtub, characterized by switching to a cleaning circulation path after circulating for a predetermined time in the path.