Bathtub cleaning device

Abstract

This invention provides a technology that can suppress the adhesion of detergent to the microbubble generation area. [Solution] The bathtub cleaning device may include a spray nozzle installed inside the bathtub, a cleaning channel whose upstream end is connected to a water supply source and whose downstream end is connected to the spray nozzle, a detergent tank for storing detergent, a detergent mixing unit installed in the cleaning channel for mixing the detergent stored in the detergent tank with the water flowing through the cleaning channel, and a microbubble generating unit installed in the part of the cleaning channel upstream of the detergent mixing unit for generating microbubbles in the water flowing through the cleaning channel. The bathtub cleaning device may be configured to perform a bathtub cleaning operation in which water containing microbubbles and mixed with detergent is sprayed from the spray nozzle to clean the bathtub.

Description

Technical Field

[0001] The technology disclosed in this specification relates to a bathtub cleaning device.

Background Art

[0002] In Patent Document 1, there is disclosed a bathtub cleaning device including an injection nozzle provided inside a bathtub, a cleaning path having an upstream end connected to a water supply source and a downstream end connected to the injection nozzle, a detergent tank for storing detergent, a detergent mixing section provided in the cleaning path for mixing the detergent stored in the detergent tank with water flowing in the cleaning path, and a fine bubble generating section provided in a portion of the cleaning path downstream of the detergent mixing section for generating fine bubbles in the water flowing through the cleaning path.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the bathtub cleaning device of Patent Document 1, since the fine bubble generating section is provided on the downstream side of the detergent mixing section, the water mixed with the detergent passes through the fine bubble generating section. For this reason, the detergent may adhere to the fine bubble generating section, and the performance of the fine bubble generating section may deteriorate. As a result, the cleaning effect of the bathtub cleaning operation may not be maintained in the long term. In this specification, a technology capable of maintaining the cleaning effect of the bathtub cleaning operation in the long term is provided.

Means for Solving the Problems

[0005] In a first aspect of this technology, the bathtub cleaning device may include: a spray nozzle provided inside the bathtub; a cleaning channel whose upstream end is connected to a water source and whose downstream end is connected to the spray nozzle; a detergent tank for storing detergent; a detergent mixing unit provided in the cleaning channel for mixing the detergent stored in the detergent tank with the water flowing through the cleaning channel; and a microbubble generating unit provided in the portion of the cleaning channel upstream of the detergent mixing unit for generating microbubbles in the water flowing through the cleaning channel. The bathtub cleaning device may be configured to perform a bathtub cleaning operation in which water containing microbubbles and mixed with detergent is sprayed from the spray nozzle to clean the bathtub.

[0006] With the above configuration, the microbubble generation unit is located upstream of the detergent mixing unit, so the water mixed with detergent does not pass through the microbubble generation unit. This prevents detergent from adhering to the microbubble generation unit, thus preventing a decrease in the performance of the microbubble generation unit. As a result, the cleaning effect of the bathtub cleaning operation can be maintained over the long term. In addition, since there is no need to use detergent-resistant materials in the microbubble generation unit, the bathtub cleaning device can be manufactured at a low cost.

[0007] In this specification, various embodiments of the "microbubble generation unit" are conceivable. For example, one embodiment is conceivable in which dissolved gas is precipitated as microbubbles by reducing the pressure of water in which gas is dissolved. Alternatively, one embodiment is conceivable in which the bubbles are made finer by swirling or colliding water mixed with bubbles.

[0008] In a second aspect of this technology, in the first aspect described above, the bathtub cleaning device may further include a flow control valve provided in the portion of the cleaning passage upstream of the detergent mixing section, for adjusting the flow rate of water flowing through the cleaning passage. The microbubble generating section may be provided in the portion of the cleaning passage upstream of the detergent mixing section and downstream of the flow control valve.

[0009] If a flow control valve is installed downstream of the microbubble generation unit, the valve will create resistance to the water flowing into the microbubble generation unit. As a result, the water in the microbubble generation unit may not be sufficiently depressurized, potentially reducing the amount of gas precipitated from the water, i.e., the amount of microbubbles generated by the microbubble generation unit. In contrast, with the above configuration, the flow control valve is installed upstream of the microbubble generation unit, so the valve does not create resistance to the water flowing into the microbubble generation unit. As a result, the water in the microbubble generation unit is sufficiently depressurized, increasing the amount of microbubbles generated by the microbubble generation unit. This further promotes the rinsing of dirt during the bathtub cleaning operation. In other words, the cleaning effect of the bathtub cleaning operation can be further improved.

[0010] In a third aspect of this technology, in the first aspect described above, the bathtub cleaning device may further include at least one backflow prevention unit, each provided in a portion of the cleaning passage upstream of the detergent mixing unit, which prevents the water flowing through the cleaning passage from flowing back into the water source. The microbubble generating unit may be provided in a portion of the cleaning passage upstream of the detergent mixing unit and downstream of any one of the at least one backflow prevention unit.

[0011] If a backflow prevention unit is located downstream of the microbubble generation unit, the backflow prevention unit will resist the water flowing into the microbubble generation unit. As a result, the water in the microbubble generation unit may not be sufficiently depressurized, potentially reducing the amount of gas precipitated from the water, i.e., the amount of microbubbles generated by the microbubble generation unit. In contrast, with the above configuration, one of the backflow prevention units is located upstream of the microbubble generation unit. A backflow prevention unit located upstream of the microbubble generation unit does not resist the water flowing into the microbubble generation unit. As a result, the water in the microbubble generation unit is sufficiently depressurized, increasing the amount of microbubbles generated by the microbubble generation unit. This further promotes the rinsing of dirt during the bathtub cleaning operation. In other words, the cleaning effect of the bathtub cleaning operation can be further improved. The above effect becomes more pronounced as the number of backflow prevention units located upstream of the microbubble generation unit is increased (i.e., the number of backflow prevention units located downstream of the microbubble generation unit is decreased).

[0012] In a fourth aspect of this technology, in the first aspect described above, the bathtub cleaning device may further include a flow control valve provided in the portion of the cleaning passage upstream of the detergent mixing section for adjusting the flow rate of water flowing through the cleaning passage, and at least one backflow prevention unit, each provided in the portion of the cleaning passage upstream of the detergent mixing section and downstream of the flow control valve, for preventing water flowing through the cleaning passage from flowing back into the water supply source. The microbubble generating unit may be provided in the portion of the cleaning passage upstream of the detergent mixing section and downstream of any one of the at least one backflow prevention unit.

[0013] If the flow control valve and backflow prevention unit are located downstream of the microbubble generation unit, they will create resistance to the water flowing into the microbubble generation unit. As a result, the water in the microbubble generation unit may not be sufficiently depressurized, potentially reducing the amount of gas precipitated from the water, i.e., the amount of microbubbles generated by the microbubble generation unit. In contrast, with the above configuration, either the flow control valve or the backflow prevention unit is located upstream of the microbubble generation unit. The flow control valve and backflow prevention unit located upstream of the microbubble generation unit do not create resistance to the water flowing into the microbubble generation unit. As a result, the water in the microbubble generation unit is sufficiently depressurized, increasing the amount of microbubbles generated by the microbubble generation unit. This further promotes the rinsing of dirt during the bathtub cleaning operation. In other words, the cleaning effect of the bathtub cleaning operation can be further improved.

[0014] In a fifth aspect of this technology, in any one of the first to fourth aspects described above, the bubble diameter of the microbubbles generated by the microbubble generating unit may be less than 1 μm.

[0015] If the diameter of the microbubbles is large, the force separating the microbubbles from the water (such as buoyancy) becomes stronger, making them more likely to separate. Therefore, after water containing microbubbles (or water mixed with detergent) is sprayed into the bathtub, the microbubbles may disappear immediately. Also, if the diameter of the microbubbles is large, it becomes more difficult for the microbubbles to penetrate the dirt. In contrast, with the above configuration, the diameter of the microbubbles is very small, making it difficult for the microbubbles to separate from the water. Therefore, after water containing microbubbles is sprayed into the bathtub, the microbubbles remain in the water for a long time. Also, because the diameter of the microbubbles is very small, they penetrate the dirt more easily. This further promotes the rinsing of dirt during the bathtub cleaning operation. In other words, the cleaning effect of the bathtub cleaning operation can be further improved. [Brief explanation of the drawing]

[0016] [Figure 1] This diagram schematically shows the configuration of the bathtub cleaning device 2 of Example 1. [Figure 2]This is a cross-sectional view of the microbubble generator 190 included in the bathtub cleaning device 2 of Example 1. [Figure 3] This is a flowchart of the bathtub cleaning operation performed by the controller 8 of the bathtub cleaning device 2 in Example 1 (or a flowchart of the bathtub cleaning operation performed by the controller 104 of the bathtub cleaning device 102 in Example 2). [Figure 4] This diagram schematically shows the configuration of the bathtub cleaning device 102 of Example 2. [Modes for carrying out the invention]

[0017] (Example 1: Bathtub cleaning device 2) As shown in Figure 1, the bathtub cleaning device 2 is installed between the bathtub 4, which is located in a house or the like, and the water supply source 6 (for example, a municipal water supply). The bathtub cleaning device 2 cleans the bathtub 4 using water supplied from the water supply source 6. The bathtub cleaning device 2 is a bathtub cleaning device that uses the water pressure from the water supply source 6 to supply water to the bathtub 4 (a so-called direct pressure system).

[0018] The bathtub cleaning device 2 is equipped with a controller 8 that includes a CPU, ROM, RAM, etc. Various operating programs are stored in the ROM. Various signals input to the controller 8 and various data generated during the process of the CPU executing processing are temporarily stored in the RAM. The controller 8 controls each component of the bathtub cleaning device 2 by having the CPU execute processing based on the information stored in the ROM and RAM. The controller 8 is also capable of bidirectional communication with a remote control 10 installed in the kitchen or bathroom. The remote control 10 presents various information about the bathtub cleaning device 2 to the user and accepts various operations from the user to the bathtub cleaning device 2.

[0019] The bathtub cleaning device 2 further includes a cleaning passage 12, a flow control valve 14, a flow sensor 16, a temperature sensor 18, a cleaning valve 20, a first backflow prevention unit 22, a second backflow prevention unit 24, a third backflow prevention unit 26, a detergent tank 28, a detergent mixing unit 30, a spray nozzle 32, a drain plug 34, and a microbubble generator 190.

[0020] The upstream end of the washing channel 12 is connected to the water supply source 6 via the water supply channel 36. A heat source 38 is provided in the water supply channel 36. The heat source 38 heats the water flowing through the water supply channel 36, for example, by burning fuel gas. Therefore, water heated by the heat source 38 is supplied to the upstream end of the washing channel 12. In the washing channel 12, a flow control valve 14 is provided near the upstream end of the washing channel 12. The flow control valve 14 adjusts the flow rate of water flowing through the washing channel 12 by adjusting the opening of a valve body (not shown). Note that the flow control valve 14 is not limited to one that adjusts the opening of the valve body by a motor, but may be a constant flow valve, for example. Also in the washing channel 12, a flow sensor 16 is provided downstream of the flow control valve 14. The flow sensor 16 detects the flow rate of water flowing through the washing channel 12. Also in the washing channel 12, a temperature sensor 18 is provided downstream of the flow sensor 16. A temperature sensor 18 detects the temperature of the water flowing through the cleaning passage 12. A cleaning valve 20 is provided downstream of the temperature sensor 18 in the cleaning passage 12. The cleaning valve 20 is an on / off valve. The cleaning valve 20 is normally closed. The cleaning valve 20 is opened when water is supplied to the bathtub 4. A first backflow prevention unit 22 is provided downstream of the cleaning valve 20 in the cleaning passage 12. The first backflow prevention unit 22 comprises two check valves 40 and 42, and a first drainage passage 44 connected to the portion of the cleaning passage 12 between the two check valves 40 and 42. The two check valves 40 and 42 each allow water to flow from upstream to downstream in the cleaning passage 12, and prohibit water from flowing from downstream to upstream in the cleaning passage 12. An atmospheric release valve (not shown) is provided in the first drainage passage 44. The atmospheric release valve is normally closed, but opens in the event of a water outage (i.e., the water supply from the water source 6 stops), and discharges the water downstream of the first backflow prevention unit 22 into the first drainage channel 44. In addition, a second backflow prevention unit 24 is provided downstream of the first backflow prevention unit 22 in the washing channel 12. The second backflow prevention unit 24 includes a relief valve 46 and a second drainage channel 48 connected to the relief valve 46. When water flows in from the upstream side, the relief valve 46 closes the second drainage channel 48, allowing the water to flow downstream of the second backflow prevention unit 24.On the one hand, when water flows from the downstream side, the relief valve 46 opens the second drainage channel 48 to discharge the water into the second drainage channel 48. In other words, the relief valve 46 allows water to flow from the upstream side to the downstream side and prohibits water from flowing from the downstream side to the upstream side (i.e., backflow). Also, in the cleaning channel 12, a third backflow prevention part 26 is provided on the downstream side of the second backflow prevention part 24. The third backflow prevention part 26 is a check valve. The third backflow prevention part 26 allows water to flow in the direction from the upstream to the downstream of the cleaning channel 12 and prohibits water from flowing in the direction from the downstream to the upstream of the cleaning channel 12. Also, in the cleaning channel 12, a detergent mixing part 30 is provided on the downstream side of the third backflow prevention part 26.

[0021] The detergent mixing part 30 includes a detergent channel 50, a detergent valve 52, and a mixer 54. The detergent channel 50 connects between the detergent tank 28 and the mixer 54. The detergent valve 52 is provided in the detergent channel 50 and opens and closes the detergent channel 50. The detergent valve 52 is normally closed. The detergent valve 52 opens when detergent is supplied from the detergent tank 28 to the cleaning channel 12. Also, the mixer 54 is a venturi and generates a negative pressure when water flows inside. Due to the negative pressure generated by the mixer 54, the detergent stored in the detergent tank 28 is drawn into the mixer 54 through the detergent channel 50. The detergent drawn into the mixer 54 is mixed with the water flowing inside the mixer 54. Thereby, a liquid in which detergent is mixed with water (also called a cleaning liquid) is generated.

[0022] The downstream end of the cleaning channel 12 is connected to the injection nozzle 32. The injection nozzle 32 is inside the bathtub 4 and provided on the bottom wall of the bathtub 4. The injection nozzle 32 injects the water supplied from the cleaning channel 12 toward the side wall of the bathtub 4. Also, at a position different from the injection nozzle 32 on the bottom wall of the bathtub 4, a drain port 4a is formed. The drain plug 34 is provided at the drain port 4a and opens and closes the drain port 4a. When the drain plug 34 is opened, the drain port 4a is opened, and the water stored in the bathtub 4 is discharged through the drain port 4a.

[0023] In this embodiment, a microbubble generator 190 is provided in the portion of the washing passage 12 between the first backflow prevention section 22 and the second backflow prevention section 24.

[0024] As shown in Figure 2, the microbubble generator 190 comprises a casing 194, a first microbubble generator 196, and a second microbubble generator 198. The casing 194 has a substantially cylindrical shape. The casing 194 can also be considered part of the washing passage 12 (see Figure 1). An inlet 200 into which water flows is provided at the upstream end of the casing 194. An outlet 202 into which water flows out is provided at the downstream end of the casing 194. The first microbubble generator 196 is housed in the casing 194. The first microbubble generator 196 comprises a body 204 and a plurality of venturi channels 206 that penetrate the body 204. Each of the multiple Venturi channels 206 includes a narrowing channel 208 whose channel diameter decreases as it moves from upstream to downstream, and an expanding channel 210 located downstream of the narrowing channel 208, whose channel diameter increases as it moves from upstream to downstream. Between the narrowing channel 208 and the expanding channel 210, there is a throat section 209 where the channel diameter of the Venturi channel 206 is smallest. The second microbubble generator 198 is housed in a casing 194 downstream of the first microbubble generator 196. The second microbubble generator 198 includes a shaft portion 212 extending in the direction from upstream to downstream, an outer peripheral portion 214 surrounding the radially outer side of the shaft portion 212, and a plurality of blade portions 216 provided between the shaft portion 212 and the outer peripheral portion 214. A swirling channel 218 is formed between the shaft portion 212, the outer circumference portion 214, and the multiple blade portions 216.

[0025] As shown in Figure 1, the bathtub cleaning device 2 further includes an air supply passage 56. The upstream end of the air supply passage 56 opens to an air supply location (not shown) (for example, inside the casing housing the bathtub cleaning device 2). The downstream end of the air supply passage 56 is connected to the cleaning passage 12 via a microbubble generator 190. Specifically, the downstream end of the air supply passage 56 is connected to the throat portion 209 of the venturi passage 206 (see Figure 2).

[0026] When water flows through the microbubble generator 190 shown in Figure 2, the water first flows into the venturi channel 206 of the first microbubble generator 196. As the water passes through the narrowed-diameter channel 208 of the venturi channel 206, the pressure is reduced to below atmospheric pressure. As a result, air that was previously dissolved in the water flowing through the narrowed-diameter channel 208 precipitates as bubbles. In addition, negative pressure (pressure below atmospheric pressure) is generated in the throat section 209 through which the water reduced in pressure in the narrowed-diameter channel 208 passes. This negative pressure draws air from the air supply point into the throat section 209 via the air supply passage 56 (see Figure 1). The air drawn into the throat section 209 mixes with the water flowing through the throat section 209 as bubbles. Therefore, the water flowing from the throat section 209 into the widened-diameter channel 210 contains bubbles that have precipitated from the water, as well as bubbles drawn in from the air supply passage 56. Subsequently, as the water passes through the widened channel 210, its pressure is increased to above atmospheric pressure. This causes the bubbles in the water to split, becoming microbubbles. The water that flows out from the Venturi channel 206 flows into the swirling channel 218 of the second microbubble generator 198. As the water flows through the swirling channel 218, a swirling flow is generated, in which the water flows spirally around the shaft 212. At this time, the microbubbles in the water become even finer due to the shear force caused by the swirling flow. In this way, microbubbles are generated in the channel (i.e., the washing channel 12) where the microbubble generator 190 is installed. The diameter of the microbubbles generated by the microbubble generator 190 is less than 1 μm.

[0027] (Bathtub cleaning operation) The controller 8 causes the bathtub cleaning device 2 to clean the bathtub 4 by executing the bathtub cleaning operation shown in Figure 3. When the controller 8 receives an instruction to start cleaning the bathtub 4, for example via the remote control 10, it starts the bathtub cleaning operation.

[0028] When the bathtub cleaning operation is started, the controller 8 performs a drainage process. In the drainage process, the controller 8 opens the drain plug 34. This allows the water stored in the bathtub 4 to be discharged through the drain port 4a. The controller 8 waits for a predetermined time (for example, 10 minutes) with the drain plug 34 open, and then ends the drainage process. The waiting time in the drainage process is the time required for the bathtub 4 to be empty. When the drainage process ends, the drain plug 34 remains open. If the drain plug 34 is already open when the bathtub cleaning operation is started, the controller 8 may skip the drainage process.

[0029] After the drainage process, the controller 8 performs a pre-cleaning process. During the pre-cleaning process, the controller 8 opens the cleaning valve 20. This allows water to flow through the cleaning passage 12, so that water from the water source 6 is supplied to the spray nozzle 32 via the cleaning passage 12. At this time, the controller 8 adjusts the opening of the flow control valve 14 so that the flow rate detected by the flow sensor 16 is a predetermined flow rate (for example, 6 liters / minute). The water supplied to the spray nozzle 32 is sprayed from the spray nozzle 32 toward the side wall of the bathtub 4. At this time, the detergent valve 52 is closed, so water without detergent is sprayed from the spray nozzle 32. When the elapsed time since the start of the pre-cleaning process exceeds a predetermined time (for example, 40 seconds), the controller 8 terminates the pre-cleaning process. When the pre-cleaning process is completed, the controller 8 closes the cleaning valve 20.

[0030] After the preliminary cleaning step, the controller 8 performs a cleaning step. The cleaning step includes a cleaning fluid injection step in which cleaning fluid is injected from the injection nozzle 32, and a waiting step in which the controller waits for a predetermined time.

[0031] When the cleaning process begins, the controller 8 executes the cleaning fluid injection process. In the cleaning fluid injection process, the controller 8 opens the cleaning valve 20 and the detergent valve 52. This allows water to flow into the cleaning passage 12. At this time, the controller 8 sets the opening degree of the flow rate control valve 14 to a predetermined opening degree. For example, the controller 8 stores the opening degree of the flow rate control valve 14 adjusted in the pre-cleaning process and sets the stored opening degree as the opening degree of the flow rate control valve 14 in the cleaning fluid injection process. In the detergent mixing unit 30, detergent is mixed with the water flowing through the cleaning passage 12 to generate cleaning fluid. Cleaning fluid is supplied to the injection nozzle 32. The cleaning fluid supplied to the injection nozzle 32 is sprayed from the injection nozzle 32 toward the side wall of the bathtub 4. The cleaning fluid sprayed from the injection nozzle 32 adheres to the wall surface of the bathtub 4. The cleaning fluid adhering to the wall surface of the bathtub 4 clings to the dirt (e.g., sebum) adhering to the wall surface. The spraying time of the cleaning solution in the cleaning solution spraying process is, for example, 3 seconds.

[0032] After the cleaning solution spraying process, the controller 8 performs a standby process. During the standby process, the controller 8 closes the cleaning valve 20 and the detergent valve 52. This stops the spraying of cleaning solution from the spray nozzle 32. In this state, the controller 8 waits for a predetermined time (for example, 40 seconds). During this time, the cleaning solution adhering to the walls of the bathtub 4 penetrates the dirt.

[0033] The controller 8 terminates the cleaning process after repeating the cleaning solution spraying process and the waiting process a predetermined number of times (for example, twice).

[0034] After the washing process, the controller 8 executes the rinsing process. During the rinsing process, the controller 8 opens the washing valve 20. This causes water to be sprayed from the spray nozzle 32 toward the side wall of the bathtub 4, washing away any cleaning solution adhering to the wall surface of the bathtub 4. At this time, the detergent valve 52 is closed, so water without detergent is sprayed from the spray nozzle 32. The controller 8 adjusts the opening of the flow rate adjustment valve 14 so that the flow rate detected by the flow rate sensor 16 is a predetermined flow rate (for example, 6 liters / minute). The water spraying time during the rinsing process is, for example, 90 seconds. When the rinsing process is finished, the controller 8 closes the washing valve 20. Once the rinsing process is complete, the bathtub washing operation ends.

[0035] (Features of Bathtub Cleaning Device 2) In the bathtub cleaning device 2, the water or cleaning solution sprayed from the spray nozzle 32 contains microbubbles generated by the microbubble generator 190. The microbubbles in the water or cleaning solution penetrate the dirt (e.g., sebum) adhering to the walls of the bathtub 4, lifting the dirt away. This promotes the rinsing of dirt during the bathtub cleaning operation. In other words, the cleaning effect of the bathtub cleaning operation can be improved.

[0036] Furthermore, the microbubble generator 190 is located upstream of the detergent mixing unit 30. As a result, the water mixed with detergent does not pass through the microbubble generator 190. This prevents detergent from adhering to the microbubble generator 190, thus suppressing the performance degradation of the microbubble generator 190 caused by detergent adhesion. This allows the cleaning effect of the bathtub cleaning operation to be maintained over the long term. In addition, since there is no need to use a material with detergent resistance for the microbubble generator 190, the bathtub cleaning device 2 can be manufactured at a low cost.

[0037] Furthermore, the microbubble generator 190 is installed downstream of the flow control valve 14 and the first backflow prevention unit 22. Therefore, the flow control valve 14 and the first backflow prevention unit 22 do not create resistance to the water flowing through the microbubble generator 190. As a result, the water pressure in the microbubble generator 190 is sufficiently reduced, increasing the amount of microbubbles generated by the microbubble generator 190. This further promotes the rinsing of dirt during the bathtub cleaning operation. In other words, the cleaning effect of the bathtub cleaning operation can be further improved.

[0038] Furthermore, the microbubbles generated by the microbubble generator 190 have a very small diameter, less than 1 μm. As a result, after the water containing the microbubbles is sprayed into the bathtub 4, the microbubbles remain in the water for a long time. Also, the microbubbles penetrate dirt more easily. This further promotes the rinsing of dirt during the bathtub cleaning operation. In other words, the cleaning effect of the bathtub cleaning operation can be further improved.

[0039] (Example 2: Bathtub cleaning device 102) As shown in Figure 4, the bathtub cleaning device 102 is installed between the bathtub 4 and the water supply source 6, similar to the bathtub cleaning device 2 (see Figure 1).

[0040] The bathtub cleaning device 102 includes a controller 104, a remote control 106, a cleaning passage 108, a flow control valve 110, a water supply valve 112, a cistern 114, a pump 116, a temperature sensor 118, a flow sensor 120, a check valve 122, a cleaning valve 124, a detergent tank 126, a detergent mixing unit 128, a spray nozzle 130, a drain plug 132, and a microbubble generator 190. The bathtub cleaning device 102 is a bathtub cleaning device that stores water supplied from a water source 6 in a cistern 114 and sends the water stored in the cistern 114 to the bathtub 4 by a pump 116 (a so-called cistern system).

[0041] The upstream end of the washing channel 108 is connected to the water supply source 6 via the water supply channel 36. Water heated by the heat source unit 38 is supplied to the upstream end of the washing channel 108. A flow control valve 110 is provided near the upstream end of the washing channel 108. The flow control valve 110 adjusts the flow rate of water flowing into the washing channel 108 by adjusting the opening of the valve body (not shown). In addition, a water supply valve 112 is provided downstream of the flow control valve 110 in the washing channel 108. The water supply valve 112 is an on / off valve. A cistern 114 is provided downstream of the water supply valve 112 in the washing channel 108. When the water supply valve 112 is opened, water is supplied to the cistern 114.

[0042] The cistern 114 includes a water reservoir 134 for storing water. The water reservoir 134 is open to the atmosphere. The portion of the washing channel 108 upstream of the water reservoir 134 is connected to the inside of the water reservoir 134 via a water supply port 134a that opens into the inside of the water reservoir 134. The water reservoir 134 is equipped with a high-level electrode 136a and a low-level electrode 136b for detecting the water level inside. The water level detected by the high-level electrode 136a (i.e., the high water level) is higher than the water level detected by the low-level electrode 136b (i.e., the low water level). When the water level inside the water reservoir 134 falls below the low water level, the bathtub washing device 102 opens the water supply valve 112 to replenish water from the water supply source 6 to the water reservoir 134 via the water supply channel 36 and the washing channel 108. Subsequently, when the water level inside the water reservoir 134 reaches the high water level, the bathtub cleaning device 102 closes the water supply valve 112 and stops supplying water to the water reservoir 134. Thus, the water level inside the water reservoir 134 is maintained between the high and low water levels. The cistern 114 also includes an overflow passage 138 for discharging water that overflows from the water reservoir 134. The upstream end of the overflow passage 138 is connected to the inside of the water reservoir 134 via an overflow port 140 that opens into the inside of the water reservoir 134. The downstream end of the overflow passage 138 is connected to a drainage location (not shown). In the vertical direction, the lower end of the overflow port 140 is positioned above the lower end of the high water level electrode 136a (i.e., the high water level) and below the water supply port 134a. If the water level inside the reservoir 134 rises above the high water level for any reason and reaches the height of the lower end of the overflow port 140, the water in the reservoir 134 flows into the overflow port 140. The water that flows into the overflow port 140 is discharged to the drainage point via the overflow passage 138. This prevents the water overflowing from the reservoir 134 from flowing into the water supply port 134a (i.e., preventing the water in the reservoir 134 from flowing back). In other words, the cistern 114 separates the wash passage 108 upstream of the cistern 114 from the wash passage 108 downstream of the cistern 114.

[0043] In the washing channel 108, a pump 116 is provided downstream of the cistern 114 (specifically, the water reservoir 134). The pump 116 draws water stored in the water reservoir 134 through the washing channel 108 and pumps it downstream of the washing channel 108.

[0044] In the cleaning channel 108, a temperature sensor 118 is provided downstream of the pump 116. The temperature sensor 118 detects the temperature of the water flowing through the cleaning channel 108. Specifically, the temperature sensor 118 detects the temperature of the water immediately after it is pumped out by the pump 116. Also in the cleaning channel 108, a flow rate sensor 120 is provided downstream of the temperature sensor 118. The flow rate sensor 120 detects the flow rate of the water flowing through the cleaning channel 108. Specifically, the flow rate sensor 120 detects the flow rate of the water immediately after it is pumped out by the pump 116. Also in the cleaning channel 108, a check valve 122 is provided downstream of the flow rate sensor 120. The check valve 122 allows water to flow from upstream to downstream in the cleaning channel 108 and prohibits water from flowing from downstream to upstream in the cleaning channel 108. In other words, the check valve 122 prevents water from flowing backward in the cleaning channel 108. Furthermore, in the washing passage 108, a washing valve 124 is provided downstream of the check valve 122. The washing valve 124 is an on / off valve. The washing valve 124 is normally closed. The washing valve 124 is opened when water is supplied to the bathtub 4. Also, in the washing passage 108, a detergent mixing section 128 is provided downstream of the washing valve 124.

[0045] The detergent mixing unit 128 comprises a detergent passage 142, a detergent valve 144, and a mixer 146. The detergent passage 142 connects the detergent tank 126 and the mixer 146. The detergent valve 144 is located in the detergent passage 142 and opens and closes the detergent passage 142. The detergent valve 144 is normally closed. The detergent valve 144 opens when detergent is supplied from the detergent tank 126 to the washing passage 108. The mixer 146 is a venturi, which generates negative pressure when water flows inside it. The negative pressure generated by the mixer 146 draws the detergent stored in the detergent tank 126 into the mixer 146 through the detergent passage 142. The detergent drawn into the mixer 146 is mixed with the water flowing inside the mixer 146. This generates a cleaning solution.

[0046] The downstream end of the cleaning channel 108 is connected to a spray nozzle 130. The spray nozzle 130 is located inside the bathtub 4 and is installed on the bottom wall of the bathtub 4. The spray nozzle 130 sprays water supplied from the cleaning channel 108 toward the side wall of the bathtub 4. A drain plug 132 is installed at the drain outlet 4a and opens and closes the drain outlet 4a. When the drain plug 132 is opened, the drain outlet 4a is opened and the water stored in the bathtub 4 is discharged through the drain outlet 4a.

[0047] In this embodiment, a microbubble generator 190 is provided in the portion of the washing passage 108 between the water reservoir 134 and the pump 116. The microbubble generator 190 is the same as the one described in Embodiment 1 (see Figure 2).

[0048] The bathtub cleaning device 102 further includes an air supply passage 148. The upstream end of the air supply passage 148 is connected to the inside of the cistern 114 via an air inlet 150 that opens into the inside of the water reservoir 134. In the vertical direction, the lower end of the air inlet 150 is positioned above the upper end of the overflow port 140. The downstream end of the air supply passage 148 is connected to the cleaning passage 108 via a microbubble generator 190. Specifically, the downstream end of the air supply passage 148 is connected to the throat section 209 (see Figure 2) of the venturi flow path 206. In this embodiment, the negative pressure generated when water passes through the throat section 209 draws air from inside the cistern 114 into the throat section 209 via the air supply passage 148 from the air inlet 150.

[0049] (Bathtub cleaning operation) The controller 104 causes the bathtub cleaning device 102 to clean the bathtub 4 by executing the bathtub cleaning operation shown in Figure 3. When the controller 104 receives an instruction to start cleaning the bathtub 4, for example via the remote control 106, it starts the bathtub cleaning operation.

[0050] When the bathtub cleaning operation is started, the controller 104 performs a drainage process. In the drainage process, the controller 104 opens the drain plug 132. This allows the water stored in the bathtub 4 to be discharged through the drain port 4a. The controller 104 waits for a predetermined time (for example, 10 minutes) with the drain plug 132 open, and then ends the drainage process. The waiting time in the drainage process is the time required for the bathtub 4 to be empty. When the drainage process ends, the drain plug 132 remains open. If the drain plug 132 is already open when the bathtub cleaning operation is started, the controller 104 may skip the drainage process.

[0051] After the drainage process, the controller 104 performs a pre-cleaning process. In the pre-cleaning process, the controller 104 opens the cleaning valve 124. This allows water to be supplied from the water reservoir 134 to the spray nozzle 130. The controller 104 also drives the pump 116. When the pump 116 is driven, the water stored in the water reservoir 134 is pumped by the pump 116 towards the spray nozzle 130. At this time, the controller 104 adjusts the output (i.e., rotational speed) of the pump 116 so that the flow rate detected by the flow sensor 120 is a predetermined flow rate (for example, 6 liters / minute). The water pumped to the spray nozzle 130 is sprayed from the spray nozzle 130 towards the side wall of the bathtub 4. At this time, since the detergent valve 144 is closed, water without detergent is sprayed from the spray nozzle 130. The controller 104 terminates the pre-cleaning process when the elapsed time since the start of the pre-cleaning process exceeds a predetermined time (for example, 40 seconds). When the preliminary cleaning process is complete, the controller 104 stops the pump 116 and closes the cleaning valve 124.

[0052] After the preliminary cleaning step, the controller 104 performs a cleaning step. The cleaning step includes a cleaning fluid spraying step in which cleaning fluid is sprayed from the spray nozzle 130, and a waiting step in which the controller waits for a predetermined time.

[0053] When the cleaning process begins, the controller 104 executes the cleaning fluid injection process. In the cleaning fluid injection process, the controller 104 opens the cleaning valve 124 and the detergent valve 144 and drives the pump 116. When the pump 116 is driven, the water stored in the reservoir 134 is pumped by the pump 116 towards the injection nozzle 130. At this time, the controller 104 sets the output of the pump 116 to a predetermined output. For example, the controller 104 stores the output of the pump 116 adjusted in the pre-cleaning process and sets the stored output as the output of the pump 116 in the cleaning fluid injection process. In the detergent mixing section 128, detergent is mixed with the water flowing through the cleaning passage 108 to generate cleaning fluid. The cleaning fluid is supplied to the injection nozzle 130. The cleaning fluid supplied to the injection nozzle 130 is sprayed from the injection nozzle 130 toward the side wall of the bathtub 4. The cleaning fluid sprayed from the injection nozzle 130 adheres to the wall surface of the bathtub 4. The cleaning solution adhering to the wall surface of the bathtub 4 clings to the dirt (e.g., sebum) adhering to the wall surface. The spraying time of the cleaning solution in the cleaning solution spraying process is, for example, 3 seconds.

[0054] After the cleaning solution spraying process, the controller 104 performs a standby process. During the standby process, the controller 104 stops the pump 116 and closes the cleaning valve 124 and the detergent valve 144. This stops the spraying of cleaning solution from the spray nozzle 130. In this state, the controller 104 waits for a predetermined time (for example, 40 seconds). During this time, the cleaning solution adhering to the walls of the bathtub 4 penetrates the dirt.

[0055] The controller 104 terminates the cleaning process after repeating the cleaning solution spraying process and the waiting process a predetermined number of times (for example, twice).

[0056] After the washing process, the controller 104 executes the rinsing process. In the rinsing process, the controller 104 opens the washing valve 124 and drives the pump 116. As a result, water is sprayed from the spray nozzle 130 toward the side wall of the bathtub 4, washing away the washing solution adhering to the wall surface of the bathtub 4. At this time, the detergent valve 144 is closed, so water without detergent is sprayed from the spray nozzle 130. The controller 104 adjusts the output (i.e., rotational speed) of the pump 116 so that the flow rate detected by the flow sensor 120 is a predetermined flow rate (for example, 6 liters / minute). The water spraying time in the rinsing process is, for example, 90 seconds. When the rinsing process is finished, the controller 104 stops the pump 116 and closes the washing valve 124. When the rinsing process is finished, the bathtub washing operation ends.

[0057] (Features of the bathtub cleaning device 102) In the bathtub cleaning device 102, the water or cleaning solution sprayed from the spray nozzle 130 contains microbubbles generated by the microbubble generator 190. The microbubbles in the water or cleaning solution penetrate the dirt (e.g., sebum) adhering to the walls of the bathtub 4, lifting the dirt away. This promotes the rinsing of dirt during the bathtub cleaning operation. In other words, the cleaning effect of the bathtub cleaning operation can be improved.

[0058] Furthermore, the microbubble generator 190 is located upstream of the detergent mixing unit 128. As a result, the water mixed with detergent does not pass through the microbubble generator 190. This prevents detergent from adhering to the microbubble generator 190, thus suppressing the performance degradation of the microbubble generator 190 caused by detergent adhesion. This allows the cleaning effect of the bathtub cleaning operation to be maintained over the long term. In addition, since there is no need to use a material with detergent resistance for the microbubble generator 190, the bathtub cleaning device 102 can be manufactured at a low cost.

[0059] Furthermore, the microbubble generator 190 is installed downstream of the flow control valve 110 (example of a backflow prevention unit). Therefore, the flow control valve 110 does not resist the water flowing through the microbubble generator 190. As a result, the water pressure in the microbubble generator 190 is sufficiently reduced, increasing the amount of microbubbles generated by the microbubble generator 190. Also, the microbubble generator 190 is installed downstream of the water reservoir 134, which is open to the atmosphere, and upstream of the pump 116. Therefore, when the pump 116 is driven, the water pressure flowing through the microbubble generator 190 decreases to a very small value due to the combined effect of the water pressure reduction associated with the pump 116's suction and the water pressure reduction by the microbubble generator 190. This further increases the amount of microbubbles generated by the microbubble generator 190. This further promotes the rinsing of dirt during the bathtub cleaning operation. In other words, the cleaning effect of the bathtub cleaning operation can be further improved.

[0060] (modified version) (See Figures 1 and 4) The water supply channel 36 does not necessarily have to be equipped with a heat source 38. In this case, water from the water source 6 may be supplied to the washing channel 108 without being heated.

[0061] (See Figure 1) The microbubble generator 190 may be provided in a different part of the washing passage 12 than in Example 1. For example, the microbubble generator 190 may be provided in the part of the washing passage 12 between the third backflow prevention section 26 and the detergent mixing section 30.

[0062] (See Figure 4) The microbubble generator 190 may be provided in a different part of the washing passage 108 than in Example 2. For example, the microbubble generator 190 may be provided in the part of the washing passage 108 between the washing valve 124 and the detergent mixing section 128.

[0063] The microbubble generator 190 may be replaced with a microbubble generator of a different form. For example, the microbubble generator 190 may be replaced with one comprising a pressurizer (e.g., a pressurized tank) that pressurizes the liquid to dissolve air into the liquid, and a vacuum generator (e.g., a venturi) that reduces the pressure of the liquid to precipitate microbubbles.

[0064] (See Figures 1 and 4) The bathtub cleaning device 2 does not need to have an air supply passage 56. Similarly, the bathtub cleaning device 102 does not need to have an air supply passage 148. Even in this case, the microbubble generator 190 can generate microbubbles based on the air dissolved in the water flowing through the cleaning passages 12 and 108, or the mixed air.

[0065] The bubble diameter of the microbubbles generated by the microbubble generator 190 may be 1 μm or larger. The bubble diameter of the microbubbles may be, for example, 1 μm or more and less than 100 μm.

[0066] The technical elements described herein or in the drawings demonstrate technical usefulness individually or in various combinations, and are not limited to the combinations described in the claims at the time of filing. Furthermore, the technologies illustrated herein or in the drawings can achieve multiple objectives simultaneously, and achieving even one of these objectives constitutes technical usefulness in itself. [Explanation of Symbols]

[0067] 2: Bathtub cleaning device, 4: Bathtub, 4a: Drain, 6: Water source, 8: Controller, 10: Remote control, 12: Cleaning channel, 14: Flow control valve, 16: Flow sensor, 18: Temperature sensor, 20: Cleaning valve, 22: First backflow prevention unit, 24: Second backflow prevention unit, 26: Third backflow prevention unit, 28: Detergent tank, 30: Detergent mixing unit, 32: Spray nozzle, 34: Drain plug, 36: Water supply channel 38: Heat source unit, 40: Check valve, 42: Check valve, 44: First drain channel, 46: Relief valve, 48: Second drain channel, 50: Detergent channel, 52: Detergent valve, 54: Mixer, 56: Air supply channel, 102: Bathtub cleaning device, 104: Controller, 106: Remote control, 108: Cleaning channel, 110: Flow control valve, 112: Water supply valve, 114: Cistern, 116: Pump, 118: Temperature sensor S, 120: Flow sensor, 122: Check valve, 124: Wash valve, 126: Detergent tank, 128: Detergent mixing unit, 130: Spray nozzle, 132: Drain plug, 134: Water reservoir, 134a: Water supply port, 136a: High water level electrode, 136b: Low water level electrode, 138: Overflow passage, 140: Overflow port, 142: Detergent passage, 144: Detergent valve, 146: Mixer, 148 : Air intake passage, 150: Air intake port, 190: Microbubble generator, 194: Casing, 196: First microbubble generator, 198: Second microbubble generator, 200: Inlet, 202: Outlet, 204: Body, 206: Venturi flow path, 208: Reduced diameter flow path, 209: Throat section, 210: Expanded diameter flow path, 212: Shaft section, 214: Outer circumference section, 216: Blade section, 218: Swirling flow path

Claims

1. A spray nozzle installed inside the bathtub, A washing path is connected to a water source at its upstream end and to the injection nozzle at its downstream end, A detergent tank for storing detergent, A detergent mixing unit is provided in the washing passage and mixes the detergent stored in the detergent tank with the water flowing through the washing passage. A bathtub cleaning device comprising a microbubble generating unit provided in the portion of the cleaning passage upstream of the detergent mixing unit, which generates microbubbles in the water flowing through the cleaning passage, The bathtub cleaning device is configured to perform a bathtub cleaning operation in which water containing fine bubbles and mixed with detergent is sprayed from the spray nozzle to clean the bathtub.

2. The bathtub cleaning device further includes a flow control valve provided in the portion of the cleaning passage upstream of the detergent mixing section, which adjusts the flow rate of water flowing through the cleaning passage. The bathtub cleaning device according to claim 1, wherein the microbubble generating section is provided in the portion of the cleaning passage upstream of the detergent mixing section and downstream of the flow rate control valve.

3. Each of the bathtub cleaning devices is further provided with at least one backflow prevention unit, which is located in the portion of the cleaning passage upstream of the detergent mixing unit, and which prevents the water flowing through the cleaning passage from flowing back into the water supply source. The bathtub cleaning device according to claim 1, wherein the microbubble generating section is provided in the portion of the cleaning passage upstream of the detergent mixing section and downstream of any one of the at least one backflow prevention section.

4. The aforementioned bathtub cleaning device is A flow control valve is provided in the part of the washing passage upstream of the detergent mixing section, which adjusts the flow rate of water flowing through the washing passage. Each of the wash passages is provided in a portion upstream of the detergent mixing section and downstream of the flow control valve, and further comprises at least one backflow prevention unit that prevents the water flowing through the wash passage from flowing back into the water supply source. The bathtub cleaning device according to claim 1, wherein the microbubble generating section is provided in the portion of the cleaning passage upstream of the detergent mixing section and downstream of any one of the at least one backflow prevention section.

5. The bathtub cleaning device according to any one of claims 1 to 4, wherein the diameter of the microbubbles generated by the microbubble generating unit is less than 1 μm.

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