Hot and cold water circulation system

Abstract

We provide a simple, space-saving, and low-cost tankless hot and cold water circulation system. [Solution] The present invention comprises a bathtub 2, an overflow channel 3, a recovery pit tank 4, a pump 5, a replenishment device 7, a water level sensor 71, a replenishment solenoid valve 72, a bathtub suction pipe 61 connecting the suction ports 21 and 22 to the pump 5, and a pit suction pipe 62 connecting the bathtub suction pipe 61 to a pit suction port 41 formed on the bottom surface of the recovery pit tank 4, and designed so that the flow rate is less than the flow rate of the bathtub suction pipe 61. The pump 5 draws in hot water through the pit suction pipe 62 and the bathtub suction pipe 61, and the pit suction pipe 62 is designed so that the flow rate of hot water flowing through the pit suction pipe 62 is equal to the flow rate of hot water flowing from the bathtub 2 to the recovery pit tank 4 via the overflow channel 3 due to the operation of the pump 5.

Description

Technical Field

[0001] The present invention relates to a hot and cold water circulation system.

Background Art

[0002] Some bathtubs are equipped with a hot and cold water circulation system for circulating, filtering, and reusing hot and cold water. For example, Japanese Patent Application Laid-Open No. 2003-311107 discloses a configuration provided with a recovery tank for recovering hot and cold water overflowing from a bathtub. In a conventional overflow-type bathtub, the hot and cold water in the recovery tank is configured to be sent to a tank disposed below by gravity. When a certain amount of hot and cold water accumulates in the tank, the hot and cold water in the tank is sent to a filtration device by a pump. In the recovery of hot and cold water in the recovery tank, the tank was necessary to suppress air biting due to pump drive.

[0003] Also, for example, Japanese Patent Application Laid-Open No. 2006-43410 discloses a configuration in which the inside of a bathtub is partitioned into two tanks and the bottoms of both tanks are connected. According to this, one functions as a bathtub and the other functions as a recovery tank (tank).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] In conventional hot water circulation systems installed in overflow-type bathtubs (hereinafter simply referred to as "hot water circulation systems"), it was necessary to place a large tank below the bathtub (for example, underground) to suppress air entrapment in the pump, as described above. The presence of the tank was an obstacle to system implementation from the standpoint of securing installation space and manufacturing and maintenance costs.

[0006] Furthermore, in a configuration where a partition is installed in the bathtub to connect both bottoms, one of the partitioned sides also functions as a tank, requiring a considerable capacity, resulting in a large overall size. In other words, this configuration is intended for large bathtubs such as those found in public bathhouses. In addition, a bottom connection port and a flow rate adjustment mechanism must be installed between the two tubs, making the system configuration relatively complex and increasing the risk of malfunction and maintenance costs. Thus, conventional systems have significant barriers to introduction from the perspective of installation space and manufacturing / maintenance costs, making them particularly difficult to install in small bathtubs, such as those in hotel rooms or private homes.

[0007] The objective of this invention is to provide a simple, space-saving, and low-cost tankless hot and cold water circulation system. [Means for solving the problem]

[0008] The present invention provides a hot water circulation system comprising: a bathtub having an intake port and an outlet port; an overflow channel formed in a part of the upper periphery of the bathtub and positioned lower than the rest of the bathtub; a recovery pit tank provided at a position corresponding to the overflow channel so that hot water flowing out of the bathtub into the overflow channel flows in from the upper opening; a pump that draws in hot water from the intake port of the bathtub and discharges it into the bathtub from the outlet port; a replenishment device that supplies new hot water to the bathtub; a water level sensor that detects the water level in the recovery pit tank; a valve that adjusts the supply amount of the replenishment device, which opens and closes based on the detection result of the water level sensor; a bathtub suction pipe connecting the intake port and the pump; and a pit suction pipe that connects a pit intake port formed on the bottom surface of the recovery pit tank to the bathtub suction pipe, and is designed so that the flow rate is less than the flow rate of the bathtub suction pipe. The pump draws in hot water from the recovery pit tank via the pit suction pipe and the bathtub suction pipe. The pit suction piping is designed such that the flow rate of hot water flowing through the pit suction piping is equal to the flow rate of hot water flowing from the bathtub to the recovery pit tank via the overflow channel due to the operation of the pump. The pit suction piping may be designed such that the flow rate of hot water flowing through the pit suction piping is less than the flow rate of hot water flowing from the bathtub to the recovery pit tank via the overflow channel due to the operation of the pump, by a predetermined amount. [Effects of the Invention]

[0009] According to the present invention, since the flow rate of the pit suction piping is equal to the flow rate of the overflow into the recovery pit tank, the water level in the recovery pit tank can be maintained without employing a large recovery tank or a complex configuration, and air buildup in the pump can be prevented. In other words, according to the present invention, a simple, space-saving, and low-cost tankless hot and cold water circulation system can be realized. [Brief explanation of the drawing]

[0010] [Figure 1]This is a diagram showing the configuration of the hot and cold water circulation system according to the first embodiment. [Figure 2] This is a conceptual diagram of the bathtub of the first embodiment, viewed from above. [Figure 3] This is a conceptual diagram of the recovery pit tank of the first embodiment. [Figure 4] This is a diagram showing the configuration of the hot and cold water circulation system according to the second embodiment. [Figure 5] This is a diagram illustrating the configuration of the hot and cold water circulation system according to the third embodiment. [Modes for carrying out the invention]

[0011] Hereinafter, a hot and cold water circulation system 1, which is one embodiment of the present invention, will be described in detail with reference to the figures. It should be noted that, in addition to the embodiments described below, the present invention can be implemented in various forms with various modifications and improvements based on the knowledge of those skilled in the art.

[0012] <First Embodiment> As shown in Figure 1, the hot water circulation system 1 of the first embodiment includes a bathtub 2, an overflow channel 3, a recovery pit tank 4, a pump 5, a bathtub suction pipe 61, a pit suction pipe 62, a replenishment device 7, a water level sensor 71, a replenishment solenoid valve 72, a filtration device 8, and a heating device 9.

[0013] Bathtub 2 has an open top. Bathtub 2 is a typical bathtub, and in the first embodiment it is a small bathtub for 1 to 3 people (for example, with a capacity of about 400 to 700 liters). Bathtub 2 has intake ports 21, 22 and discharge port 23. The number and location of the intake ports and discharge port can be set arbitrarily. In the first embodiment, intake ports 21 and 22 are formed on the bottom surface of bathtub 2, and discharge port 23 is formed on the side surface of bathtub 2.

[0014] As shown in Figures 1 and 2, the overflow channel 3 is formed in a part of the upper periphery of the bathtub 2 and is located at a lower position than other parts. The overflow channel 3 has a flat bottom surface and sides that rise up on both sides of the bottom surface. The overflow channel 3 connects the upper part of the bathtub 2 to the upper part of the recovery pit tank 4. The bottom surface of the overflow channel 3 is located at a lower position than the upper periphery of the bathtub 2 (the part other than the overflow channel 3). When the water in the bathtub 2 reaches a certain level, that is, when the water level exceeds the bottom surface of the overflow channel 3, it flows into the recovery pit tank 4 via the overflow channel 3.

[0015] The recovery pit tank 4 is a container-shaped component positioned to correspond to the overflow channel 3, so that the hot water that flows out of the bathtub 2 into the overflow channel 3 flows in through the opening at the top. The recovery pit tank 4 can also be described as a small side ditch with an open top. The capacity of the recovery pit tank 4 may be, for example, less than 1 / 4 of the bathtub 2. The sound and visual effect of the hot water from the bathtub 2 flowing down into the recovery pit tank 4 via the overflow channel 3 is created. The recovery pit tank 4 is formed to be sufficiently deep (for example, more than 1 / 3 of the depth of the bathtub 2) so that a sound (for example, a sound like a waterfall) is produced when the hot water flows down. The depth of the recovery pit tank 4 is, for example, the same as the depth of the bathtub 2. In addition, debris floating on the surface of the water in the bathtub 2 flows down into the recovery pit tank 4 along with the hot water, maintaining the cleanliness of the water surface in the bathtub 2.

[0016] A pit inlet 41 and a drain outlet 42 are formed on the bottom surface of the recovery pit tank 4. The pit inlet 41 is connected to the pit suction pipe 62. The drain outlet 42 is connected to the drain pipe 421. A valve member 422 is provided in the drain pipe 421. The drain pipe 421 is used, for example, when it is desired to completely drain the water from the recovery pit tank 4. In addition, a side drain outlet 43 is formed on the side of the recovery pit tank 4. When the water level in the recovery pit tank 4 reaches the side drain outlet 43, the water in the recovery pit tank 4 is drained from the side drain outlet 43. The drain outlet 42 may be omitted.

[0017] The pump 5 is an electric pump. The pump 5 is a device that uses a motor as a driving source and utilizes negative pressure to inhale and discharge liquid. The pump 5 inhales hot and cold water from the inlets 21 and 22 of the bathtub 2, and discharges it into the bathtub 2 from the discharge port 23 via the filtration device 8 (main body 80) and the heating device 9. The pump 5 is disposed inside the filtration device 8. The pump 5 can also be said to be a device that circulates hot and cold water through the filtration device 8. The heating device 9 of the first embodiment is a device that heats the hot and cold water inhaled by the pump 5 (the hot and cold water passing through the filtration device 8), and is a heat exchanger disposed inside the filtration device 8.

[0018] The bathtub suction pipe 61 is a pipe member that connects the inlets 21 and 22 of the bathtub 2 and the pump 5. The bathtub suction pipe 61 is provided with a valve member 611 whose flow rate can be adjusted (for example, opened and closed), and a check valve 612 that permits only the flow from the inlets 21 and 22 to the pump 5. Further, a valve member 613 whose flow rate can be adjusted is provided in front of the pump 5 of the bathtub suction pipe 61. The arrangement of the valves in the bathtub suction pipe 61 is in the order of the valve member 611, the check valve 612, and the valve member 613 from the inlets 21 and 22 toward the pump 5.

[0019] The pit suction pipe 62 is a pipe member that connects the pit inlet 41 formed on the bottom surface of the recovery pit tank 4 and the bathtub suction pipe 61. The pit suction pipe 62 is designed such that its flow rate is smaller than the flow rate of the bathtub suction pipe 61. The pit suction pipe 62 is provided with a valve member 621 whose flow rate can be adjusted (for example, opened and closed), and a check valve 622 that permits only the flow from the inlets 21 and 22 to the pump 5. The pit suction pipe 62 is connected between the check valve 612 and the valve member 613 of the bathtub suction pipe 61. The pump 5 inhales the hot and cold water in the recovery pit tank 4 into the filtration device 8 via the pit suction pipe 62 and the bathtub suction pipe 61.

[0020] The pipes are arranged in each part. For example, the discharge pipe 63 is a pipe member that connects the pump 5 and the discharge port 23 of the bathtub 2. The pump 5 sucks hot water from the bathtub 2 and the recovery pit tank 4 through the bathtub suction pipe 61 and the pit suction pipe 62, passes the hot water through the filtering device 8 (main body 80) and the heating device 9, and discharges the filtered and heated hot water into the bathtub 2 through the discharge pipe 63. The hot water is circulated by the pump 5, the bathtub suction pipe 61, the pit suction pipe 62, and the discharge pipe 63.

[0021] The pit suction pipe 62 is designed such that the flow rate of the hot water flowing through the pit suction pipe 62 is equal to the flow rate of the hot water flowing from the bathtub 2 into the recovery pit tank 4 through the overflow channel 3 due to the drive of the pump 5. In the first embodiment, since the valve member 621 is provided in the pit suction pipe 62, the above conditions are realized by adjusting the opening degree of the valve member 621.

[0022] In the first embodiment, the flow rate of the hot water flowing from the bathtub 2 into the recovery pit tank 4 through the overflow channel 3 (hereinafter, also referred to as "overflow flow rate") and the flow rate of the hot water flowing out from the pit suction port 41 of the recovery pit tank 4, that is, the flow rate of the pit suction pipe 62 (hereinafter, also referred to as "pit suction flow rate") are (substantially) equal in design. Note that the pit suction pipe 62 and / or the valve member 621 can also be designed such that "overflow flow rate ≥ pit suction flow rate". When preventing air leakage is the top priority, the pit suction flow rate may be set to be smaller than the overflow flow rate (for example, the difference is 0.5 liters / second or less). From the viewpoints of preventing air leakage and the efficiency of hot water, it is preferable to design such that substantially "overflow flow rate = pit suction flow rate" (including some design allowances and errors). In the first embodiment, the overflow flow rate caused by the drive of the pump 5 corresponds to the flow rate of the hot water discharged from the discharge port 23.

[0023] If the designer has determined, for example, through prior calculations, that the overflow flow rate is 10 liters / second, then the structure of the valve member 621 and / or the pit suction piping 62 should be adjusted so that the pit suction flow rate is 10 liters / second. Alternatively, instead of adjusting the valve member 621, the pit suction piping 62 may be used with its flow path cross-sectional area (opening area) and length already adjusted to achieve the desired pit suction flow rate. In this case, the valve member 621 is no longer an essential component in the adjustment process.

[0024] The replenishment device 7 is a device that supplies fresh hot water to the bathtub 2. The replenishment device 7 can also be called a water heater. The replenishment device 7 generates hot water by heating water through the combustion of fuel (for example, gas). The temperature of the hot water is higher than the user's set water temperature. The replenishment device 7 supplies the hot water to the filtration device 8 via the first pipe 701 as a heat source for the heating device 9. The heating device 9 is a heat exchanger that exchanges heat between the hot water flowing through the first pipe 701 and the hot water drawn in by the pump 5. The hot water is heated by heat exchange with the hot water. The heat-exchanged hot water returns to the replenishment device 7 via the second pipe 702. The replenishment device 7 can also be called a filtration and heating water heater.

[0025] The replenishment device 7 further includes a high-temperature pipe 703 for carrying hot water, a low-temperature pipe 704 for carrying unheated water (water at a lower temperature than the hot water), a temperature control valve 705, and a supply pipe 706. The high-temperature pipe 703 is a piping component that connects the replenishment device 7 and the temperature control valve 705. The replenishment device 7 supplies hot water to the temperature control valve 705 via the high-temperature pipe 703.

[0026] The low-temperature pipe 704 is a piping component that connects the replenishment device 7 and the temperature control valve 705. The replenishment device 7 supplies unheated water (e.g., tap water) to the temperature control valve 705 via the low-temperature pipe 704.

[0027] The temperature control valve 705 mixes hot water and cold water according to the opening degree (water temperature) set by the user and supplies it to the supply pipe 706. The supply pipe 706 is a piping member that connects the temperature control valve 705 and the supply port 707. The supply port 707 is an opening that allows hot water to flow out toward the bathtub 2, and in the first embodiment, it is located on the upper periphery of the bathtub 2. In this way, new hot water is supplied from the replenishment device 7 to the bathtub 2 via the temperature control valve 705, the supply pipe 706, and the supply port 707. Each of the pipes 701 to 704 is equipped with a valve member that can adjust the flow rate. The supply pipe 706 is equipped with a replenishment solenoid valve 72 that can adjust the flow rate by electricity.

[0028] The water level sensor 71 is a sensor that detects the water level in the recovery pit tank 4. The water level sensor 71 is an electrode-type water level sensor (level sensor) that has multiple electrode rods and detects the water level by determining whether or not current is flowing through each electrode rod. The water level sensor 71 is positioned to measure the water level in the recovery pit tank 4. For example, the water level sensor 71 is connected to a drain pipe 421 that is connected to the drain port 42 of the recovery pit tank 4. The water level sensor 71 is connected between a valve member 422 provided in the drain pipe 421 and the drain port 42. For example, the valve member 422 is normally closed, so that the water level in the recovery pit tank 4 and the water level in the water level sensor 71 are linked. Note that the water level sensor does not have to be electrode-type; for example, it may be electronic, and the mechanism can be arbitrarily selected. The water level sensor 71 is electrically connected to a replenishment solenoid valve 72.

[0029] The replenishment solenoid valve 72 is a valve that adjusts the supply amount of the replenishment device 7, and is a solenoid valve that opens and closes based on the detection result of the water level sensor 71. The flow rate of the supply pipe 706 changes as the opening degree of the replenishment solenoid valve 72 changes, and the amount of new hot water supplied changes. The state (opening degree, open or closed) of the replenishment solenoid valve 72 changes in response to the signal from the water level sensor 71.

[0030] The filtration device 8 is a device that filters the hot water drawn in by the pump 5. The hot water drawn in from the bathtub 2 and the recovery pit tank 4 via the bathtub suction pipe 61 and the pit suction pipe 62 is filtered by the main body 80 of the filtration device 8, heated by the heating device 9, and returned to the bathtub 2 via the discharge pipe 63. The pump 5 and the heating device 9 (heat exchanger) are located inside the housing of the filtration device 8.

[0031] (Unoccupied, bathtub water level at maximum) The following describes the state in which there are no bathers in the bathtub 2, the water level in the bathtub 2 is at its maximum level, and the water level in the recovery pit tank 4 is above the level at which the pit intake port 41 is not exposed to the atmosphere (hereinafter also referred to as the unoccupied maximum state). The unoccupied maximum state is, for example, when the maximum capacity of the bathtub 2 is 500 liters, there are 500 liters of hot water in the bathtub 2 and, for example, 50 liters of hot water in the recovery pit tank 4. In this state, the pump 5 operates.

[0032] When pump 5 is activated, the hot water circulates, and the hot water in bathtub 2 flows into the recovery pit tank 4 via the overflow channel 3. The maximum water level in bathtub 2 corresponds to the bottom surface level of the overflow channel 3. The amount of hot water functioning in the hot water circulation system 1 in the unoccupied maximum state is greater than the capacity of bathtub 2, as it includes the volume of the circulation channel and is designed to overflow due to circulation. In the unoccupied maximum state, the hot water always overflows due to the operation of pump 5. In the unoccupied maximum state, no hot water is supplied from the replenishment device 7.

[0033] From a water level of 0 to the maximum unoccupied state, hot water is supplied from the replenishment device 7. For example, when the bathtub 2 reaches its maximum water level and overflow occurs, hot water flows into the recovery pit tank 4, and when the piping on each suction side is filled with hot water, the water level in the recovery pit tank 4 increases.

[0034] When the water level in the recovery pit tank 4 reaches a predetermined level, the replenishment solenoid valve 72 closes based on the value detected by the water level sensor 71, and the supply of hot and cold water from the replenishment device 7 stops. If the user wishes to lower the water level in the recovery pit tank 4 to a desired level (set water level), they can do so, for example, by opening the valve member 422.

[0035] The set water level is set at a position where the drain cover (metal) of the pit intake port 41 is not exposed to the atmosphere. In other words, the set water level is set higher than the upper surface of the drain cover of the pit intake port 41. For example, as shown in Figure 3, the set water level may be set slightly higher than the upper surface of the drain cover of the pit intake port 41 (for example, 1 mm to 20 mm above the upper surface of the drain cover) so that the hot water covers the drain cover of the pit intake port 41. By setting a small value for the set water level, it is possible to secure the "height" at which the hot water flows down into the recovery pit tank 4, and the sound of the hot water flowing down can be made more effective. This improves the atmosphere. In addition, by reducing the amount of water that accumulates in the recovery pit tank 4, it is possible to further suppress the growth of bacteria.

[0036] The user can achieve the set water level by adjusting the water level by draining from a predetermined level. The predetermined water level and the set water level may be equal. In the unoccupied maximum state where the water level in the recovery pit tank 4 is at the set water level, the circulation of hot and cold water due to the operation of the pump 5 maintains the flow of hot and cold water from the bathtub 2 to the recovery pit tank 4 via the overflow channel 3.

[0037] In this unmanned maximum state, the pit suction flow rate and the overflow flow rate are equal. As a result, in the unmanned maximum state, overflow occurs due to the circulation of hot and cold water, while the water level in the recovery pit tank 4 is maintained at the set level. In other words, the pit suction port 41 is prevented from being exposed to the atmosphere, and air contamination of the pump 5 is prevented. With this configuration, there is no need to install a separate large recovery tank, and the setup and maintenance costs of the hot and cold water circulation system 1, as well as the required installation space, are reduced. The overflow flow rate can be said to be the flow rate caused solely by the operation of the pump 5 (circulation in the unmanned maximum state).

[0038] The set water level in the recovery pit tank 4 is set to a sufficient level so that even if the user drains the water from the bathtub 2 multiple times using a bucket before bathing, and the overflow temporarily stops, the pit intake port 41 will not be exposed to the atmosphere. In addition, the replenishment solenoid valve 72 opens, for example, when the water level in the recovery pit tank 4 falls below the set water level, and closes when it rises above the set water level.

[0039] (When a person enters the bath after it has been completely empty) When a person enters the bathtub after it has been empty for the maximum time, the overflow flow rate will temporarily increase. This will cause the water level in the recovery pit tank 4 to rise. The water that flows into the recovery pit tank 4 may be drained out through the side drain outlet 43. In addition, the water may overflow and be drained out from parts other than the overflow channel 3 at the upper periphery of the bathtub 2. In other words, the water in the bathtub 2 may be drained, and the amount of circulating water may decrease.

[0040] After bathing, when the water level in bathtub 2 reaches its maximum and settled state (hereinafter also referred to as the "maximum bathing state"), overflow occurs due to the circulation of the bathwater, similar to the maximum unoccupied state. The water level in the recovery pit tank 4 is maintained at a level higher than the maximum unoccupied state. Even if the state of the replenishment solenoid valve 72 (closed state) is the same as the maximum unoccupied state, continuous overflow can be generated by driving the pump 5.

[0041] When the water level in bathtub 2 drops due to the use of hot water from the bathtub 2, the overflow stops and the water level in the recovery pit tank 4 drops. When the value detected by the water level sensor 71 changes from above a predetermined threshold to below a predetermined threshold, the replenishment solenoid valve 72 opens, and new hot water is supplied to bathtub 2 from the replenishment device 7. The predetermined threshold is set based on the supply flow rate (capacity) of the replenishment device 7 when the replenishment solenoid valve 72 is opened, and the assumed maximum number of bathers in bathtub 2 or the maximum capacity of bathtub 2, so that the time it takes for the water level in bathtub 2 to reach its maximum is shorter than the time it takes for the pit intake port 41 to be exposed to the atmosphere. The predetermined threshold can also be said to be set so that the pit intake port 41 is not exposed, based on the assumed amount of water level drop, the rate at which the water level in bathtub 2 rises, and the rate at which the water level in the recovery pit tank 4 drops. The predetermined threshold is set, for example, based on the amount of rise in the water level in the recovery pit tank 4 when one child bathes, and the replenishment solenoid valve 72 also operates when one child gets out of bathtub 2.

[0042] Based on the supply flow rate and the capacity that the bathtub 2 must fill (the capacity corresponding to the assumed maximum number of people or the maximum capacity), the maximum time required for the bathtub 2 to reach its maximum water level can be calculated. A predetermined threshold is set so that the time until the pit intake port 41 (the upper end surface of the drain cover) is exposed to the atmosphere is greater than the maximum time, based on the pit intake flow rate. As a result, an overflow occurs and circulation resumes before the pit intake port 41 is exposed to the atmosphere. With this configuration, even without a water level sensor in the bathtub 2, the pit intake port 41 is prevented from being exposed to the atmosphere, and air buildup in the pump 5 is prevented.

[0043] If the water level in the recovery pit tank 4 returns to the maximum bathing state due to discharge from the pump 5 before it falls below a predetermined threshold, no new hot water is supplied, and circulation continues. In addition, to automatically return the water level in the recovery pit tank 4 to the set water level, the control device of the hot water circulation system 1 opens the valve member 422 (in this case, a solenoid valve) based on the value detected by the water level sensor 71, for example, if there is no change in the water level in the recovery pit tank 4 for a predetermined time, until the water level reaches the set water level. When the valve member 422 is open, the replenishment solenoid valve 72 remains closed regardless of the predetermined threshold. If the valve member 422 is a solenoid valve, for example, a configuration can be adopted in which the valve member 422 opens and closes based on the value detected by the water level sensor 71. This makes it possible to automatically adjust the water level in the recovery pit tank 4 to the set water level.

[0044] The valve member 422, which functions as a solenoid valve (corresponding to a drainage solenoid valve), may be configured, for example, to open when the value detected by the water level sensor 71 exceeds a drainage threshold, and to close after a predetermined time has elapsed since opening or when the value detected by the water level sensor 71 reaches a drainage stop threshold. This allows the water level in the recovery pit tank 4 to be returned to a desired level (e.g., a set water level) by draining if the water level rises.

[0045] (When the bather gets out of the bathtub) When a bather leaves bathtub 2, the water level in bathtub 2 drops, and the overflow temporarily stops. This also causes the water level in the recovery pit tank 4 to drop. Therefore, when the value detected by the water level sensor 71 falls from above a predetermined threshold to below that threshold, the replenishment solenoid valve 72 opens, and new hot water is supplied to bathtub 2 from the replenishment device 7. When the value detected by the water level sensor 71 reaches a predetermined water level (for example, the set water level), the solenoid valve closes, and the supply from the replenishment device 7 stops. Since the pump 5 continues to operate, when the water level in bathtub 2 reaches its maximum, it becomes the same as the maximum unoccupied state.

[0046] Thus, the structure of the pit suction piping 62 and / or the valve member 621 are set so that the pit suction flow rate is equal to the overflow flow rate in the unoccupied maximum state. This allows for the maintenance of the water level in the recovery pit tank 4 and the realization of a hot and cold water circulation system that prevents air buildup in the pump 5 without employing a large recovery tank or complex configuration. This configuration has fewer controls and solenoid valves, making it less prone to malfunctions and reducing the frequency of maintenance. Since the hot and cold water circulation system 1 is tankless, it is easy to miniaturize and save space, making it particularly suitable for home bathrooms and bathrooms attached to hotel rooms. In this way, according to the first embodiment, a simple, space-saving, and low-cost tankless hot and cold water circulation system can be realized.

[0047] <Second Embodiment> As shown in Figure 4, in the second embodiment, in the configuration of the first embodiment, a bathtub water level sensor 24 for detecting the water level of the bathtub 2 is provided on the bathtub 2. The bathtub water level sensor 24 is electrically connected to the replenishment solenoid valve 72. Similar to the water level sensor 71, a known configuration (for example, a configuration with multiple electrode rods or an electronic type) is adopted for the bathtub water level sensor 24. Even with the configuration that includes the bathtub water level sensor 24, the same effects as in the first embodiment are achieved.

[0048] According to the second embodiment, the presence of the bathtub water level sensor 24 allows the replenishment solenoid valve 72 to be opened and closed with greater precision. For example, when the water level of the bathtub 2 falls from its maximum level, the replenishment solenoid valve 72 opens based on the detection values ​​of the bathtub water level sensor 24 and / or the water level sensor 71, and new hot water is supplied to the bathtub 2 from the replenishment device 7. For example, the replenishment solenoid valve 72 may be set to open when the detection value of the water level sensor 71 is less than or equal to a first predetermined value and the detection value of the bathtub water level sensor 24 is less than or equal to a second predetermined value. In this way, the replenishment solenoid valve 72 opens and closes based on the detection values ​​of the bathtub water level sensor 24 and the water level sensor 71 so that the pit intake port 41 is not exposed to the atmosphere. Closing of the replenishment solenoid valve 72 is also performed based on the detection values ​​of the bathtub water level sensor 24 and / or the water level sensor 71.

[0049] Simply put, the system may be configured to open the replenishment solenoid valve 72 when the water level in the bathtub 2 drops by a certain amount. Alternatively, the system may be configured to close the solenoid valve (for example, valve member 621 or a new solenoid valve) of the pit suction piping 62 when the water level in the recovery pit tank 4 falls below a set water level.

[0050] <Third Embodiment> As shown in Figure 5, the hot and cold water circulation system 1 of the third embodiment has, in addition to the configuration of the first embodiment, a branch pipe 631 connecting the discharge pipe 63 and the supply pipe 706, and a branch solenoid valve 632 provided on the branch pipe 631. One end of the branch pipe 631 is connected between the replenishment solenoid valve 72 and the supply port 707 of the supply pipe 706. The branch solenoid valve 632 adjusts the flow rate of the branch pipe 631 by opening and closing. The branch solenoid valve 632 is configured to be linked with, for example, the replenishment solenoid valve 72, opening when the replenishment solenoid valve 72 is closed and closing when the replenishment solenoid valve 72 is open.

[0051] When the supply solenoid valve 72 is closed, and the branch solenoid valve 631 is opened, the hot water that is returned to the bathtub 2 via the discharge pipe 63 in the circulation of hot water by the pump 5 is discharged into the bathtub 2 from the discharge port 23 and the supply port 707. As a result, even when no new hot water is supplied from the supply device 7, hot water is supplied from the supply port 707, contributing to an improved atmosphere.

[0052] (others) The present invention is not limited to the above embodiments. For example, the valve member 621 may be a solenoid valve, or a solenoid valve other than the valve member 621 may be provided in the pit suction piping 62. In this case, the solenoid valve (corresponding to a drainage solenoid valve) may be configured to open and close based on the value detected by the water level sensor 71, and to close when the water level falls below a predetermined value until the water level reaches a desired level. When the water level drops, the solenoid valve closes before the pit suction port 41 is exposed to the atmosphere, thereby preventing air buildup. The predetermined value is set, for example, to 10 mm or more above the pit suction port 41 when the thickness of the drain cover of the pit suction port 41 is 5 to 6 mm.

[0053] Furthermore, the connection position (junction position) of the pit suction pipe 62 to the bathtub suction pipe 61 is not limited to the above embodiment and can be set arbitrarily. However, the connection position in the above embodiment is preferred. In other words, in the above embodiment, the pit suction pipe 62 is connected to the end of the bathtub suction pipe 61 on the side of the filtration device 8 (pump 5). This allows the pit suction pipe 62 to transport the hot water from the recovery pit tank 4 to just before the inlet of the filtration device 8 by itself. This allows the hot water from the recovery pit tank 4, which is relatively prone to bacterial growth, to be quickly transported to the filtration device 8, thereby promoting the maintenance of clean hot water. In the above embodiment, the pit suction pipe 62 is connected to the bathtub suction pipe 61 via a connecting member (for example, a T-shaped connecting member) to which the valve member 613 is connected, between the valve member 613 and the check valve 612. It can be said that the pit suction pipe 62 is directly connected to the inlet (suction port) of the filtration device 8 via the connecting member and the valve member 613.

[0054] Furthermore, the bottom of the recovery pit tank 4 may be shaped like a mortar towards the pit intake port 41. The replenishment device 7 may also supply hot spring water. The valve member 621 that adjusts the flow rate of the pit intake pipe 62 can be omitted by adjusting the flow rate through the structure of the pit intake pipe 62. In addition, the hot water circulation system 1 can achieve effects such as creating a pleasant atmosphere and collecting garbage, even without a filtration device 8 or a heating device 9.

[0055] (Structure of this disclosure) A first embodiment of the hot water circulation system 1 of the present disclosure comprises a bathtub 2 having inlet ports 21, 22 and outlet port 23; an overflow channel 3 formed in a part of the upper periphery of the bathtub 2 and positioned lower than the rest of the bathtub 2; a recovery pit tank 4 provided at a position corresponding to the overflow channel 3 (for example, an adjacent position) so that hot water flowing out of the bathtub 2 into the overflow channel 3 flows in from the upper opening; a pump 5 that draws in hot water from the inlet ports 21, 22 of the bathtub 2 and discharges it back into the bathtub 2 from the outlet port 23; a replenishment device 7 that supplies new hot water to the bathtub 2; a water level sensor 71 that detects the water level in the recovery pit tank 4; a replenishment solenoid valve 72 that adjusts the supply amount of the replenishment device 7 and opens and closes based on the detection result of the water level sensor 71; a bathtub suction pipe 61 that connects the inlet ports 21, 22 and the pump 5; and a pit suction pipe 62 that connects a pit inlet 41 formed on the bottom surface of the recovery pit tank 4 to the bathtub suction pipe 61, and is designed so that the flow rate is smaller than the flow rate of the bathtub suction pipe 61. Pump 5 draws hot water from the recovery pit tank 4 via the pit suction pipe 62 and the bathtub suction pipe 61. The pit suction pipe 62 is designed so that the flow rate of hot water flowing through the pit suction pipe 62 is equal to the flow rate of hot water flowing from the bathtub 2 into the recovery pit tank 4 via the overflow passage 3 due to the operation of pump 5.

[0056] In the second embodiment of the hot and cold water circulation system 1, the pit suction pipe 62 is provided with a valve member 622 that can adjust the flow rate, as in the first embodiment. In the third form of the hot water circulation system 1, in the first or second form, the replenishment solenoid valve 72 opens when the value detected by the water level sensor 71 falls below a predetermined threshold from a state where it was above a predetermined threshold. The predetermined threshold is set based on the supply flow rate of the replenishment device 7 when the replenishment solenoid valve 72 is opened and the assumed maximum number of bathers in the bathtub 2 or the maximum capacity of the bathtub 2, such that the time it takes for the water level in the bathtub 2 to reach its maximum is shorter than the time it takes for the pit intake port 41 to be exposed to the atmosphere.

[0057] The fourth form of the hot water circulation system 1 further includes a bathtub water level sensor 24 for detecting the water level of the bathtub 2, as in any of the first to third forms. The replenishment solenoid valve 72 opens and closes based on the values ​​detected by the bathtub water level sensor 24 and the water level sensor 71 so that the pit intake port 41 is not exposed to the atmosphere.

[0058] In the fifth form of the hot and cold water circulation system 1, a drain pipe 421 is connected to the recovery pit tank 4 in any of the first to fourth forms. The drain pipe 421 is equipped with a drain solenoid valve 422 that opens and closes based on the value detected by a water level sensor 71. The drain solenoid valve 422 is configured to open when the value detected by the water level sensor 71 exceeds a drainage threshold, and to close after a predetermined time has elapsed since opening or when the value detected by the water level sensor 71 reaches a drainage stop threshold.

[0059] The sixth embodiment of the hot water circulation system 1 includes, in any of the first to fifth embodiments, a filtration device 8 for filtering the hot water drawn in by the pump 5, and a heating device 9 for heating the hot water drawn in by the pump 5. Furthermore, in this configuration, it is preferable that the pit suction pipe 62 is connected to the end of the bathtub suction pipe 61 on the filtration device 8 side (seventh embodiment).

[0060] In the eighth form of the hot and cold water circulation system 1, the pit suction pipe 62 is designed such that the flow rate of hot and cold water flowing through the pit suction pipe 62 (pit suction flow rate) is smaller than the flow rate of hot and cold water flowing from the bathtub 2 to the recovery pit tank 4 via the overflow passage 3 due to the operation of the pump 5 (overflow flow rate) by a predetermined difference (for example, a predetermined difference as a margin or play). In this way, a margin may be provided, prioritizing the prevention of air entrapment. The eighth form can be combined with any of the feature parts of the second to seventh forms. The eighth form is preferably combined with the fifth form from the viewpoint of maintaining the water level of the recovery pit tank 4. The predetermined difference may be set to, for example, 0.5 liters / second or less. If a water level sensor is provided to detect the water level of the bathtub 2, it is easy to detect a drop in the water level due to the use of hot water in the bathtub 2, and hot water can be replenished immediately. For this reason, this configuration makes it easy to set a small water level in the recovery pit tank 4. For example, the replenishment solenoid valve 72 may be configured to open and close based on the detected values ​​of the bathtub water level sensor 24 and / or water level sensor 71, so that when the water level of the bathtub 2 is at its maximum value and there is no one in the bathtub 2 (maximum unoccupied state), the water level of the recovery pit tank 4 is within a range of 1 mm to 20 mm above the upper end surface of the drain cover installed at the pit intake port 41. [Explanation of Symbols]

[0061] 1...Water circulation system, 2...Bathtub, 21, 22...Inlet, 23...Outlet, 24...Bathtub water level sensor, 3...Overflow channel, 4...Recovery pit tank, 41...Pit inlet, 42...Drain 42, 421...Drain piping, 422...Valve component, 43...Side drain 43, 5...Pump, 61...Bathtub suction piping, 611, 613...Valve component, 62...Pit suction piping, 621...Valve component, 7...Replenishment device, 71...Water level sensor, 72...Replenishment solenoid valve, 8...Filtration device, 9...Heating device.

Claims

1. A bathtub having an intake port and an outlet port, An overflow channel is formed in a part of the upper periphery of the aforementioned bathtub and is positioned lower than other parts, A recovery pit tank is provided at a position corresponding to the overflow channel so that the hot water that flows out of the bathtub into the overflow channel flows in from the upper opening, A pump that draws hot water into the bathtub from the intake port and discharges it into the bathtub from the outlet port, A supply device for supplying new hot water to the aforementioned bathtub, A water level sensor for detecting the water level in the recovery pit tank, A valve for adjusting the supply amount of the replenishment device, comprising a replenishment solenoid valve that opens and closes based on the detection result of the water level sensor, A bathtub suction pipe connecting the aforementioned suction port to the pump, A pit suction pipe is provided, which connects the pit suction port formed on the bottom surface of the recovery pit tank to the bathtub suction pipe, and is designed so that the flow rate is less than that of the bathtub suction pipe. Equipped with, The pump draws hot water from the recovery pit tank through the pit suction piping and the bathtub suction piping. The pit suction piping is designed such that the flow rate of hot water flowing through the pit suction piping is equal to the flow rate of hot water flowing from the bathtub to the recovery pit tank via the overflow channel due to the operation of the pump. Hot and cold water circulation system.

2. The pit suction piping is provided with a valve member that can adjust the flow rate. The hot and cold water circulation system according to claim 1.

3. The replenishment solenoid valve opens when the water level sensor's detected value falls from above a predetermined threshold to below the predetermined threshold. The predetermined threshold is, Based on the supply flow rate of the replenishment device when the replenishment solenoid valve is opened, and the assumed maximum number of bathers in the bathtub or the maximum capacity of the bathtub, the time it takes for the water level in the bathtub to reach its maximum is set to be shorter than the time it takes for the pit intake to be exposed to the atmosphere. The hot and cold water circulation system according to claim 1.

4. The bathtub water level sensor further comprises a bathtub water level sensor for detecting the water level of the bathtub, The replenishment solenoid valve opens and closes based on the detected value of the bathtub water level sensor and the detected value of the water level sensor, so that the pit intake port is not exposed to the atmosphere. The hot and cold water circulation system according to claim 1.

5. The replenishment solenoid valve opens and closes based on the bathtub water level sensor and / or the water level sensor's detection value, so that when the water level in the bathtub is at its maximum and no one is in the bathtub, the water level in the recovery pit tank is within a range of 1 mm to 20 mm above the upper end surface of the drain cover installed at the pit intake. The hot and cold water circulation system according to claim 4.

6. The aforementioned recovery pit tank is connected to a drainage pipe. The drainage piping is equipped with a drainage solenoid valve that opens and closes based on the value detected by the water level sensor. The drain solenoid valve is configured to open when the water level sensor detects a value equal to or greater than the drain threshold, and to close after a predetermined time has elapsed since opening or when the water level sensor detects a value equal to the drain stop threshold. The hot and cold water circulation system according to claim 1.

7. A filtration device for filtering the hot water drawn in by the aforementioned pump, A heating device for heating the hot water drawn in by the aforementioned pump, A hot and cold water circulation system according to any one of claims 1 to 6, comprising:

8. The pit suction piping is connected to the end of the bathtub suction piping on the filtration device side. The hot and cold water circulation system according to claim 7.

9. A bathtub having an intake port and an outlet port, An overflow channel is formed in a part of the upper periphery of the aforementioned bathtub and is positioned lower than other parts, A recovery pit tank is provided at a position corresponding to the overflow channel so that the hot water that flows out of the bathtub into the overflow channel flows in from the upper opening, A pump that draws hot water into the bathtub from the intake port and discharges it into the bathtub from the outlet port, A supply device for supplying new hot water to the aforementioned bathtub, A water level sensor for detecting the water level in the recovery pit tank, A valve for adjusting the supply amount of the replenishment device, comprising a replenishment solenoid valve that opens and closes based on the detection result of the water level sensor, A bathtub suction pipe connecting the aforementioned suction port to the pump, A pit suction pipe is provided, which connects the pit suction port formed on the bottom surface of the recovery pit tank to the bathtub suction pipe, and is designed so that the flow rate is less than that of the bathtub suction pipe. Equipped with, The pump draws hot water from the recovery pit tank through the pit suction piping and the bathtub suction piping. The pit suction piping is designed such that the flow rate of hot water flowing through the pit suction piping is less than the flow rate of hot water flowing from the bathtub to the recovery pit tank via the overflow channel due to the operation of the pump, by a predetermined amount. Hot and cold water circulation system.

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