Hot water system

Abstract

To provide a hot water system for preventing a freeze of water in a trap region of an overflow pipe which is arranged at a water supply tank.SOLUTION: A hot water supply system comprises: a heating heat source; a hot water storage tank; a water supply tank; a pump; a water supply pipe for supplying the water of a water supply source to the water supply tank; a water supply valve for opening and closing the water supply pipe; an overflow pipe for draining redundant water in the water supply tank in which a water level in the water supply tank exceeds a prescribed height; a trap part arranged in the middle of the overflow pipe, and sealing water by accumulating a part of the water; atmospheric temperature detection means for detecting an atmospheric temperature; and a control device. When the atmospheric temperature is lower than a prescribed threshold, and a prescribed determination time elapses in a state that the water supply valve is in a valve-closed state, the control device valve-opens the water supply valve as a freeze prevention operation of the overflow pipe, maintains the valve-opened state of the water supply valve up until an overflow pipe water conduction state that the redundant water flows into the overflow part and the redundant water is conducted to the trap part is detected, and valve-closes the water supply valve when the overflow pipe conduction state is detected.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a hot water supply system that includes a hot water storage tank, a water supply tank, a pump, etc., and supplies hot water to hot water terminals such as showers and faucets. [Background technology]

[0002] Conventionally, in a hot water supply system, in order to be able to supply a sufficient amount of hot water even when hot water is used simultaneously by multiple hot water terminals such as showers and faucets, a hot water supply system is known which is equipped with a heating heat source, a hot water storage tank for storing hot water heated by the heating heat source, a water supply tank for storing water from the water supply source, a pump for supplying water from the water supply tank and hot water from the hot water storage tank to the hot water terminal, a water supply pipe for supplying water from the water supply source to the water supply tank, and a water supply valve for opening and closing the water passage of the water supply pipe (Patent Document 1).

[0003] Also known is a technology for a water supply system that includes a water tank, a water supply pipe that supplies tap water to the water tank, a water supply valve attached to the water supply pipe, and a temperature sensor attached to the water supply valve, and when the temperature sensor detects an outside air temperature that could cause the water supply valve to freeze, the water supply valve opens and water is supplied for a predetermined period of time to prevent freezing, thereby preventing the water supply valve from freezing during extremely cold periods such as winter (Patent Document 2).In this water supply system, the water tank is provided with an overflow pipe that drains the stored water when the water level rises above the full water level, and the water supply for anti-freezing is carried out below the overflow water level of the overflow pipe, preventing unnecessary drainage (paragraph 0035 of Patent Document 2). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Special Publication No. 59-18613 [Patent Document 2] Patent No. 5107293 Summary of the Invention [Problem to be solved by the invention]

[0005] In a hot water supply system, an overflow pipe is provided in a water supply tank to drain excess water above a predetermined storage level to the outside. The overflow pipe may also be equipped with a trap that collects and seals a portion of the drainage water to prevent odors and bacteria from entering from downstream. However, the conventional hot water supply system (Patent Document 1) does not have such a configuration. When an overflow pipe is provided in a water supply tank, the overflow pipe is open to the atmosphere or connected to a drain pipe that is open to the atmosphere. Therefore, when the outside temperature is low, such as in winter, the water collected in the trap is likely to freeze before the water in the water supply tank. If the water in the trap freezes, the overflow pipe may be damaged, causing it to malfunction and potentially resulting in a water leak from the water supply tank. Meanwhile, the conventional water supply system (Patent Document 2) focuses on preventing the water supply valve from freezing. Furthermore, the water supply for anti-freeze purposes is provided below the overflow pipe's overflow level, so it is unable to prevent the water in the overflow pipe from freezing. Therefore, in the conventional technology, in a configuration in which an overflow pipe having the trap portion is provided in a water supply tank in a hot water supply system, it is not possible to prevent the water in the trap portion from freezing.

[0006] The present invention has been made in consideration of the above circumstances, and aims to provide a hot water supply system that makes it possible to prevent water from freezing in the trap section of an overflow pipe installed in a water supply tank. [Means for solving the problem]

[0007] The hot water supply system according to the present invention comprises: A heating source; a hot water storage tank for storing hot water heated by a heating heat source; a water supply tank for storing water from a water supply source; a pump that supplies hot water from the hot water storage tank and water from the water supply tank to the hot water outlet terminal; a water supply pipe that supplies water from a water supply source to a water supply tank; a water supply valve for opening and closing the water supply pipe; an overflow pipe for draining excess water in the water supply tank when the water level in the water supply tank exceeds a predetermined height; A trap section is provided in the middle of the overflow pipe and collects and seals a portion of the water flowing in the overflow pipe. an outside air temperature detection means for detecting an outside air temperature; a control device that controls anti-freeze operation, The control device is configured to operate to prevent the overflow pipe from freezing by opening the water supply valve when a predetermined judgment time has elapsed while the water supply valve is closed when the outside air temperature detected by the outside air temperature detection means is below a predetermined threshold temperature, and to keep the water supply valve open until it detects an overflow pipe water-passing state in which excess water flows into the overflow pipe and passes through the trap section, and to control the water supply valve to close when it detects the overflow pipe water-passing state.

[0008] According to the above configuration, when water is supplied from the water supply pipe to the water supply tank by opening the water supply valve during overflow pipe freeze prevention operation, the water supply valve remains open until the overflow pipe water flow state is detected. This allows water to continue to be supplied not only to the water supply tank but also to the water supply tank until excess water flows into the overflow pipe and passes through the trap section. Therefore, passing excess water through the trap section of the overflow pipe prevents water from freezing in the trap section. Furthermore, with this configuration, water is supplied to the water supply tank during overflow pipe freeze prevention operation, thereby preventing water in the water supply tank from freezing. Furthermore, if the water supply valve remains closed for a period of time within the threshold time, the water supply valve is not opened, thereby preventing unnecessary freeze prevention operation.

[0009] In the hot water supply system, the overflow pipe has an upstream end opening that communicates with the water supply tank and into which excess water in the water supply tank flows; an overflow water level detection means is provided for detecting when the water level in the water supply tank reaches a predetermined overflow water level at which excess water in the water supply tank flows into the overflow pipe from the upstream end opening; The control device can be configured to determine that the overflow pipe is in a water flowing state and close the water supply valve when a predetermined time (T1) has elapsed after the overflow water level detection means detects that the overflow water level has been reached.

[0010] According to this configuration, when water is supplied from the water supply pipe into the water supply tank by opening the water supply valve, the water supply valve remains open for a predetermined time (T1) even if the water level in the water supply tank reaches the overflow level. Therefore, during this predetermined time (T1), excess water in the water supply tank flows into the overflow pipe from the upstream opening and passes through the trap. Here, the predetermined time (T1) can be set, for example, to the time from when the overflow level detection means detects that the water level has reached the overflow level until the excess water flowing into the overflow pipe passes through the trap. This ensures that excess water flows into the overflow pipe, allowing excess water to pass through the trap, and reliably prevents water from freezing in the trap.

[0011] In the hot water supply system, The overflow pipe has an upstream end opening at its upper end, which communicates with the water supply tank and into which excess water from the water supply tank flows, and an overflow hole is provided between the upstream end opening and the trap section in addition to the upstream end opening, which communicates with the water supply tank and into which excess water from the water supply tank flows, A Hi water level detection means is provided to detect when the water level in the water supply tank reaches a predetermined Hi water level at which excess water in the water supply tank flows into the overflow pipe from the overflow hole, The control device can be configured to determine that the overflow pipe is in a water flowing state and close the water supply valve when a predetermined time (T2) has elapsed after the Hi water level detection means detects that the Hi water level has been reached.

[0012] According to this configuration, when the water supply valve is opened to supply water from the water supply pipe to the water supply tank, the water supply valve remains open for a predetermined time (T2) even if the water level in the water supply tank reaches the Hi water level. Therefore, during this predetermined time (T2), excess water in the water supply tank flows into the overflow pipe through the overflow hole and passes through the trap section. Because the overflow hole is located between the trap section and the upstream end opening and at a lower position than the upstream end opening, excess water in the water supply tank can flow through the overflow hole to the overflow pipe even if the water level in the water supply tank does not reach the upstream end opening of the overflow pipe, for example, because water in the water supply tank is being used at a hot water outlet or the like and is flowing out of the water supply tank. Here, the predetermined time (T2) can be set, for example, to the time from when the Hi water level detection means detects that the water level has reached the Hi water level until excess water flowing into the overflow pipe from the overflow hole passes through the trap section. Therefore, even if the water level in the water supply tank does not reach the upstream end opening of the overflow pipe, excess water can be reliably flowed into the overflow pipe through the overflow hole, allowing excess water to pass through the trap section, thereby reliably preventing water from freezing in the trap section. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a schematic configuration diagram illustrating an example of a hot water supply system according to an embodiment. [Figure 2] FIG. 2 is a diagram showing the arrangement of float sensors and an overflow pipe in the water supply tank. [Figure 3] FIG. 2 is a plan view showing the configuration of an overflow pipe. [Figure 4] 10 is a flowchart showing the operation of the overflow pipe anti-freeze operation. DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, a hot water supply system according to an embodiment of the present invention will be described. The hot water supply system X of the embodiment shown in FIG. 1 is a hot water supply system suitable for use in commercial facilities such as hair salons. It includes a hot water pressurized tank unit 1, a heat source unit 500, and a control device C. It is configured to supply a large amount of cold water or hot water from the hot water pressurized tank unit 1 to hot water outlet terminals 400, such as multiple showers and faucets. The heat source unit 500 includes a first gas heat source unit 501 and a second gas heat source unit 502, which are heating heat sources. The heating heat source may include one or more gas heat sources, or a heat pump or electric heater may be used instead of the gas heat source units. The hot water pressurized tank unit 1 includes a water supply tank 2 for storing water supplied from a water source and a hot water storage tank 6 for storing hot water heated by the heat source unit 500, enabling a large amount of hot water to be supplied to the hot water outlet terminals 400. The hot water pressurized tank unit 1 also includes an outdoor air temperature sensor 80 at the bottom of its housing for detecting the outdoor air temperature. In addition, a water leakage detection means 81 for detecting water leakage within the hot water pressure tank unit 1 is provided at the bottom of the housing of the hot water pressure tank unit 1, and if the water leakage detection means 81 detects water leakage within the hot water pressure tank unit 1 during water supply operation to the water supply tank 2, the open water supply valve 12 is closed, and the water supply operation is forcibly stopped.

[0015] The first and second gas heat source units 501, 502 are gas water heaters, and although not shown, are equipped with a gas burner, a heat exchanger, a heat source unit control device that controls the operation of the heating heat source, etc. within their housings. The first and second gas heat source units 501, 502 and the hot water storage tank 6 are connected by a heating circulation circuit consisting of a heating supply pipe 40 that sends hot water from the hot water storage tank 6 and water from the water supply tank 2 to the first and second gas heat source units 501, 502, and a heating return pipe 44 that returns the hot water heated in the first and second gas heat source units 501, 502 to the hot water storage tank 6.

[0016] The heating supply pipe 40 has one end connected to the bottom of the hot water storage tank 6, and is branched into a first heating supply pipe 41 and a second heating supply pipe 42 midway so that the other end is connected to the first gas heat source unit 501 and the second gas heat source unit 502. The heating return pipe 44 is formed by joining a first heating return pipe 45 and a second heating return pipe 46, one end of which is connected to the gas heat source units 501, 502, midway, and the other end is connected to the top of the hot water storage tank 6.

[0017] The heating return pipe 44 is provided with an automatic air vent valve 57 that opens when the pressure in the hot water storage tank 6 rises above a predetermined value, and a heating return temperature sensor 58 that detects the temperature of the hot water flowing into the hot water storage tank 6. The heating supply pipe 40 is joined with the water supply pipe 3, and upstream of the junction with the water supply pipe 3 are provided with an under-tank temperature sensor 55 that detects the temperature of the hot water supplied from the hot water storage tank 6 to the heating supply pipe 40, and a manually openable valve 56 (which may be a valve whose opening and closing is controlled by the control device C). A heating supply temperature sensor 50 is provided in the heating supply pipe 40 downstream of the junction with the water supply pipe 3, upstream of the branch point of the first and second heating supply pipes 41, 42. A first heating circulation pump 51 and a second heating circulation pump 52 are provided in the first and second heating supply pipes 41, 42, respectively, and check valves 53, 54 are provided downstream of the first and second heating circulation pumps 51, 52. By operating the first and second heating circulation pumps 51, 52 and the first and second gas heat source units 501, 502, hot water at a predetermined outlet temperature heated by the first and second gas heat source units 501, 502 is supplied to the hot water storage tank 6.

[0018] The hot water storage tank 6 is a tank made of a highly corrosion-resistant metal (e.g., stainless steel), and although not shown, its outer periphery is covered with a heat insulating material. The capacity of the hot water storage tank 6 in this embodiment is, for example, 50 liters. A heating supply pipe 40 and a hot water supply return pipe 72 that returns hot water from the hot water outlet terminal 400 are connected to the bottom of the hot water storage tank 6, and a heating return pipe 44 and a hot water supply supply pipe 71 that is connected to the hot water outlet terminal 400 are connected to the top of the hot water storage tank 6. A first hot water storage temperature sensor 61, a second hot water storage temperature sensor 62, and a third hot water storage temperature sensor 63 are attached to the hot water storage tank 6 from the top at a predetermined interval, in that order.

[0019] The water supply tank 2 is disposed above the hot water storage tank 6 and supplies water to the gas heat source units 501, 502, the hot water storage tank 6, the hot water outlet terminal 400, etc. In this embodiment, the capacity of the water supply tank 2 is, for example, 70 liters. A water supply pipe 10 that supplies city water, the water supply source, to the water supply tank 2 is connected to the top of the water supply tank 2, and a water supply outflow pipe 3 is connected to the bottom of the water supply tank 2. A governor 11 and a water supply valve 12 are installed in the water supply pipe 10, in this order from the upstream side. The water supply valve 12 is composed of a solenoid valve that serves as an on / off valve. The water supply valve 12 is connected to the control device C, and is controlled to open and close by a control signal from the control device C.

[0020] As shown in Fig. 2, the water supply tank 2 has a drain outlet 21 on one side wall below the connection port for the water supply pipe 10 and above the connection port for the water supply forward pipe 3, and an overflow pipe 9 is connected to the inside side of this drain outlet 21 in the water supply tank 2. This overflow pipe 9 drains excess water from the water supply tank 2 to the outside of the tank and collects some of the drained water to seal the water so that odors, germs, etc. do not enter from downstream. A drain pipe 200 is connected to the outside side of the water supply tank 2 from the drain outlet 21 (see Fig. 1). On the other side wall of the water supply tank 2, an overflow float sensor (overflow water level detection means) 22, a Hi float sensor (Hi water level detection means) 23, a Low float sensor 24, and a low water level float sensor 25 are arranged at predetermined intervals, in this order from top to bottom, on the other side wall of the water supply tank 2, which detect the water level in the water supply tank 2.

[0021] The overflow pipe 9 is a tubular member that drains excess water from the water supply tank 2 when the water level therein exceeds a predetermined height, and is installed within the water supply tank 2 (see FIGS. 1 and 2). As shown in FIG. 3, the overflow pipe 9 has a rising portion 91 that extends straight in the vertical direction, a substantially U-shaped trap portion 92 that is connected to the lower end of the rising portion 91 and collects and seals a portion of the drained water, and a pipe portion 93 that is connected to the trap portion 92 and extends horizontally to connect to the drain outlet 21 of the water supply tank 2. The rising portion 91 of the overflow pipe 9 is positioned higher than the trap portion 92, and its upper end forms an upstream end opening 94 that communicates with the interior of the water supply tank 2. An overflow hole 95 that communicates with the interior of the water supply tank 2 is provided in the upper part of the side wall of the rising portion 91. Therefore, when the water level in the water supply tank 2 rises and reaches the height position of the overflow hole 95, the water (excess water) in the water supply tank 2 flows from the overflow hole 95 into the overflow pipe 9. When the water level in the water supply tank 2 rises further and reaches the height position of the upstream end opening 94, the water (excess water) in the water supply tank 2 also flows from the upstream end opening 94 into the overflow pipe 9. In this way, the excess water in the water supply tank 2 flows into the overflow pipe 9 from the overflow hole 95 or from the overflow hole 95 and the upstream end opening 94, and is discharged to the outside. Here, the diameter of the upstream end opening 94 of the overflow pipe 9 is set so that the flow rate of the excess water from the upstream end opening 94 is greater than the flow rate of the water supplied from the water supply pipe 10, so that water does not overflow from the water supply tank 2 even if water continues to be supplied from the water supply pipe 10 to the water supply tank 2. On the other hand, the overflow hole 95 of the overflow pipe 9 is not intended to prevent water from overflowing from the water supply tank 2, but has a hole diameter set to allow the water in the water supply tank 2 to flow into the overflow pipe 9, and is formed to have a relatively small diameter that is smaller than the opening area of ​​the upstream end opening 94. Furthermore, as the final water level of the water supply tank 2 after water supply is completed, the water level (storage amount) in the water supply tank 2 will be the lower end position of the overflow hole 95 of the overflow pipe 9, and the water level in the overflow pipe 9 will be the lower end position of the drain outlet 21.Even if the water inside the overflow pipe 9 gradually evaporates, it is possible to maintain water sealing in the trap section 92 as long as the water level does not drop below the upper end of the horizontal part of the trap section 92. In the embodiment, one overflow hole 95 is provided, but multiple overflow holes 95 may be provided at the same height.

[0022] In this embodiment, the overflow pipe 9 is installed inside the water supply tank 2, but it may also be installed outside the water supply tank 2. When installing the overflow pipe (9) outside the water supply tank 2, for example, the rising portion (91) is bent into an L-shape, and the upstream end opening (94) of the overflow pipe (9) is connected to the drain outlet 21 from outside the water supply tank 2, and the downstream end of the pipe (93) is connected to the drain pipe 200. In addition, a straight connecting pipe may be horizontally connected to the overflow hole (95) provided in the rising portion (91) so that the overflow hole (95) communicates with the inside of the water supply tank 2 at the height of the overflow hole (95).

[0023] Referring again to Figure 2, the relationship between the height positions of each float sensor 22 to 25 in the water supply tank 2 and the overflow pipe 9 is as follows: the low water level float sensor 25 is arranged at a height position below the trap section 92, the low float sensor 24 is arranged at a height position slightly above the trap section 92, the high float sensor 23 is arranged near the overflow hole 95 at a height position slightly above the overflow hole 95, and the overflow float sensor 22 is arranged near the upstream end opening 94 at a height position slightly below the upstream end opening 94.

[0024] When the water level in the water supply tank 2 rises to a height that submerges a float built into the sensor, the float moves and turns ON in each of the float sensors 22-25. When the water level in the water supply tank 2 drops to a height that submerges the float, the float moves in the opposite direction and turns OFF as the water level drops and the float is no longer submerged. That is, when each of the float sensors 22-25 turns ON, it detects the water level in the water supply tank 2, and when it turns OFF, it detects that the water level in the water supply tank 2 has fallen below the water level at the sensor position. Specifically, the low water level float sensor 25 turns ON when the water level in the water supply tank 2 reaches a low water level that is a height position below the trap section 92 (for example, a position at 15 liters in terms of the water storage capacity of the water supply tank 2). The low float sensor 24 turns ON when the water level in the water supply tank 2 reaches a low water level that is a height position slightly above the trap section 92 (for example, a position at 45 liters in terms of the water storage capacity of the water supply tank 2). The Hi float sensor 23 turns ON when the water level in the water supply tank 2 reaches the Hi water level (for example, a 60 liter position in terms of the amount of water stored in the water supply tank 2), which is a height position slightly above the overflow hole 95 of the overflow pipe 9. The overflow float sensor 22 turns ON when the water level in the water supply tank 2 reaches the overflow water level (for example, a 64 liter position in terms of the amount of water stored in the water supply tank 2), which is a height position slightly below the upstream end opening 94 of the overflow pipe 9 and which can be said to have almost reached the upstream end opening 94. Detection signals of the water levels detected by each of the float sensors 22 to 25 are output to the control device C. It should be noted that the means for detecting the water level in the water supply tank 2 is not limited to the float sensors 22 to 25, and other contact type water level gauges such as a capacitance type or non-contact type water level gauges such as an ultrasonic type may also be used.

[0025] One end of the water supply pipe 3 is connected to the bottom of the water supply tank 2, and branches upstream into a first water supply pipe 31 and a second water supply pipe 32 so that water flows in parallel. A water supply pressure pump 37 is installed upstream of the branch point between the first water supply pipe 31 and the second water supply pipe 32. This water supply pressure pump 37 constitutes a pump that supplies hot water stored in the hot water storage tank 6 and water stored in the water supply tank 2 to the hot water outlet terminal 400.

[0026] The first water supply pipe 31 is provided with, from upstream to downstream, a check valve 33 and a pressure sensor 35 for detecting water pressure, while the second water supply pipe 32 is provided with, from upstream to downstream, a check valve 34 and a water volume sensor 36 for detecting water flow rate. While it is possible to provide a pressure sensor and a water volume sensor in a single water passage without providing such parallel water passages, it is possible to reduce pressure loss in the water supply pipe 3 by forming parallel water passages consisting of the first water supply pipe 31 and the second water supply pipe 32 so that water flows in parallel and providing a pressure sensor and a water volume sensor in each water passage. Although the water flow rate may differ in each of the first and second water supply pipes 31, 32, the water flow rate of the entire water supply pipe 3 can be calculated from the water flow rate detected by the water volume sensor 36 if the ratio of pressure loss is known.

[0027] The first water supply pipe 31 and the second water supply pipe 32 join at a junction downstream of the pressure sensor 35 and the water volume sensor 36, and the other end of the water supply pipe 3 is connected to a junction with a heating supply pipe 40 connected to the bottom of the hot water storage tank 6. Further, downstream of the junction of the first and second water supply pipes 31, 32, the water supply pipe 3 branches into a water supply branch pipe 38 connected to a hot water outlet terminal 400. The downstream side of the water supply branch pipe 38 branches into multiple pipes depending on the number of showers and faucets at the hot water outlet terminal 400. A check valve 39 is installed in the water supply pipe 3 downstream of the branch point of the water supply branch pipe 38. The water supply pipe 3, including the first and second water supply pipes 31, 32 and the water supply branch pipe 38, forms a water supply circuit, and by operating the water supply pressure pump 37, water is supplied from the water supply tank 2 to the gas heat source units 501, 502 and the hot water outlet terminal 400.

[0028] One end of the hot water return pipe 72 is connected to the bottom of the hot water storage tank 6, and the other end is connected to the hot water supply pipe 71 at the hot water outlet terminal 400. An instant hot water circulation pump 73 is installed in the hot water return pipe 72, and an instant hot water return temperature sensor 74 and a check valve 75 are installed downstream of the instant hot water circulation pump 73. The hot water supply pipe 71 and the hot water return pipe 72, which are arranged between the hot water storage tank 6 and the hot water outlet terminal 400, form an instant hot water circulation circuit.

[0029] The hot water supply system X includes a remote control R that allows a user to perform operations related to the operation of the hot water supply system X. The remote control R is connected by wire or wirelessly to the control device C and heat source device control devices (not shown) provided in the first and second gas heat source units 501, 502 so as to be able to communicate with them.

[0030] The remote control R is a terminal device configured to instruct the control device C on operational information such as turning the power of the hot water supply system X on and off, and setting the hot water storage temperature in the hot water storage tank 6 (such as the outlet temperature of the hot water discharged from the first and second gas heat source units 501, 502) in response to a user's operation of an operation switch (not shown). The remote control R is equipped with a display that displays various information about the hot water supply system X. Note that instead of or together with the remote control R, a mobile terminal such as a smartphone or tablet terminal connected to the control device C so as to be able to communicate with it can be used.

[0031] The control device C is composed of one or more electronic circuit units including a CPU, ROM, RAM, interface circuitry, etc. The memory stores various operation programs and various data such as setting values ​​for executing the operation programs. The control device C receives detection signals from the various sensors and valves described above, as well as operation information from a remote control R. The control device C controls the operation of the entire hot water supply system X by controlling the operation of the gas heat source units 501, 502, the various pumps 37, 51, 52, 73, the water supply valve 12, etc.

[0032] To summarize the main operations of this hot water supply system X, when the hot water outlet terminal 400 is opened, the water supply pressure pump 37 is operated to supply water stored in the water supply tank 2 to the hot water outlet terminal 400 via the water supply forward pipe 3 and the water supply branch pipe 38, and the water from the water supply tank 2 is supplied to the lower layer of the hot water storage tank 6 via the water supply forward pipe 3 and the heating forward pipe 40 below the tank, so that the hot water in the upper layer of the hot water storage tank 6 is supplied to the hot water outlet terminal 400 via the hot water supply forward pipe 71 (hot water outlet operation). Furthermore, when the temperature detected by the third hot water storage temperature sensor 63 installed at the bottom of the hot water storage tank 6 drops below a predetermined hot water storage start temperature, the first and second heating circulation pumps 51, 52 are operated to supply hot water from the bottom of the hot water storage tank 6 to the first and second gas heat source units 501, 502 via the heating supply pipe 40 and the first and second heating supply pipes 41, 42, and the hot water heated to a predetermined hot water outlet temperature in the first and second gas heat source units 501, 502 is supplied to the top of the hot water storage tank 6 via the first and second heating return pipes 45, 46 and the heating return pipe 44 (hot water storage operation). Furthermore, when the temperature of the hot water remaining in the hot water supply supply pipe 71 and the hot water return pipe 72 drops due to the passage of a predetermined instant hot water start time, the instant hot water circulation pump 73 is operated to send the hot water stored in the hot water storage tank 6 to the hot water supply supply pipe 71 (instant hot water operation). Furthermore, when the amount of water stored in the water supply tank 2 becomes low, the water supply valve 12 is opened to supply water from the water supply source to the water supply tank 2 via the water supply pipe 10 (water replenishment operation).

[0033] Next, the characteristic features of the present invention will be described. In the hot water supply system X of this embodiment, the control device C performs anti-freeze operation on the overflow pipe 9 provided in the water supply tank 2 by opening the water supply valve 12 when the outside air temperature P detected by the outside air temperature sensor 80 is below a predetermined threshold temperature A and a predetermined judgment time K has elapsed while the water supply valve 12 is in a closed state, and by keeping the water supply valve 12 open until it detects an overflow pipe flowing state in which excess water in the water supply tank 2 flows into the overflow pipe 9 and the excess water flows into the trap section 92, and by controlling the water supply valve 12 to close when it detects the overflow pipe flowing state.

[0034] In this embodiment, the freeze prevention operation for the overflow pipe 9 involves repeatedly controlling the opening and closing of the water supply valve 12 to open and close the overflow pipe 9, from when the outside air temperature P falls below a predetermined threshold temperature A until it reaches a predetermined stop temperature B. The overflow pipe water flow state refers to a state in which excess water in the water supply tank 2 flows into the overflow pipe 9, draining all of the water already stored in the trap section 92 and filling the trap section 92 with the excess water that has newly flowed into the overflow pipe 9. In this embodiment, it is determined that the operation to open the overflow pipe water has been performed when a predetermined time T1 has elapsed after the overflow float sensor 22 detected that the water level had reached the overflow level, or when a predetermined time T2 has elapsed after the Hi float sensor 23 detected that the water level had reached the Hi level.

[0035] The operation of the freeze prevention operation for the overflow pipe 9 will be specifically described below. 4, the anti-freeze operation for the overflow pipe 9 is performed at least while the hot water supply pressurized tank unit 1 is powered on (step S0). When the hot water supply pressurized tank unit 1 is powered on, the control device C determines (step S1) whether the outside air temperature P detected by the outside air temperature sensor 80 remains below a predetermined threshold temperature A (e.g., 3°C) for a predetermined time d (e.g., 5 seconds), and if the outside air temperature P does not remain above the threshold temperature A or below the threshold temperature A for the predetermined time d ("NO" in step S1), the process returns to step S1 and continues monitoring the outside air temperature P.

[0036] If the outside air temperature P remains below the threshold temperature A for a predetermined time d ("YES" in step S1), the control device C starts anti-freeze operation. In this case, the control device C determines whether the water supply valve 12 is closed (step S2). If the water supply valve 12 is open ("NO" in step S2), the control device C returns the process to step S2 and continues monitoring the open / closed state of the water supply valve 12.

[0037] If the water supply valve 12 is closed ("YES" in step S2), the control device C calculates a predetermined judgment time K that determines the timing to open the water supply valve 12 to start supplying water to the water supply tank 2 (step S3). If the water supply valve 12 remains closed for a long time, water will not flow into the overflow pipe 9 via the water supply tank 2 for a long time, which could cause the water accumulated in the trap portion 92 of the overflow pipe 9 to freeze. The judgment time K is set by determining the length of time that the water supply valve 12 remains closed and inactive, and determining the timing to open the water supply valve 12 to allow water to flow through the trap portion 92 before the water in the trap portion 92 freezes. The judgment time K is set according to the outside air temperature P, and is set shorter the lower the outside air temperature P. For example, if the outside air temperature P is 2°C, the judgment time K is set to 50 minutes, if the outside air temperature P is 0°C, the judgment time K is set to 20 minutes, if the outside air temperature P is -5°C, the judgment time K is set to 10 minutes, and if the outside air temperature P is -10°C, the judgment time K is set to 3 minutes. Note that the judgment time K corresponds to the time when the water in the trap section 92 is likely to freeze, so it can be set arbitrarily depending on the size and length of the trap section 92, the amount of water accumulated in the trap section 92, the installation environment of the hot water supply pressurized tank unit 1, etc.

[0038] After calculating the judgment time K in step S3, the time during which the water supply valve 12 is in the closed state is measured by counting the lapse of the calculated judgment time K (for example, by counting down the judgment time K). That is, the control device C determines whether the judgment time K has elapsed with the water supply valve 12 in the closed state (step S4).

[0039] While the water supply valve 12 is closed and the determination time K has not elapsed ("NO" in step S4), the control device C determines whether the outside air temperature P detected by the outside air temperature sensor 80 is below a predetermined stop temperature B (step S5). If the outside air temperature P is equal to or higher than the stop temperature B ("NO" in step S5), the control device C terminates the anti-freeze operation. In this case, the control device C resets the count of the determination time K and returns the process to step S1 to continue monitoring the outside air temperature P. Note that the stop temperature B in step S5 is set to a temperature higher than the threshold temperature A that starts the anti-freeze operation in step S1. In other words, if the stop temperature B is set to the same temperature as the threshold temperature A, the start and end of the anti-freeze operation will be repeated due to slight changes in the outside air temperature P. Therefore, by setting the stop temperature B to a temperature higher than the threshold temperature A, such repeated start and end of the anti-freeze operation can be prevented.

[0040] If the outside air temperature P is lower than the stop temperature B ("YES" in step S5), the control unit 10 determines whether the water supply valve 12 has been opened for a purpose other than the freeze prevention operation of the overflow pipe 9 under this control (step S6). If the water supply valve 12 has been opened for a purpose other than the freeze prevention operation ("YES" in step S6), the control unit C resets the count of the judgment time K and returns the process to step S2 to monitor the open / closed state of the water supply valve 12. Note that if the water supply valve 12 has been opened for a purpose other than the freeze prevention operation ("YES" in step S6), the control unit C may perform valve closing control of the water supply valve 12 (steps S8 and S9, described below) to allow water to pass through the overflow pipe when closing the water supply valve 12. On the other hand, if the water supply valve 12 has not been opened for a purpose other than the freeze prevention operation ("NO" in step S6), the control unit C returns the process to step S4 and continues counting the judgment time K. In addition, cases in which the water supply valve 12 is opened other than during the anti-freeze operation, which is a process that results in "YES" in step S6, include when hot water is dispensed from the hot water dispensing terminal, the water in the water supply tank 2 is used, and the water level in the water supply tank 2 becomes the replenishment water level (for example, when the water level in the water supply tank 2 becomes lower than the low water level and the low float sensor detects that it is OFF).

[0041] In step S4, if the determination time K has elapsed with the water supply valve 12 remaining closed ("YES" in step S4), the control device C issues an instruction to open the water supply valve 12, thereby opening the water supply valve 12 (step S7). As a result, water is supplied from the water supply pipe 10 into the water supply tank 2.

[0042] Next, after opening water supply valve 12, control device C keeps water supply valve 12 open until it detects an overflow pipe water flow state in which excess water in water supply tank 2 flows into overflow pipe 9 and excess water flows through trap section 92, and closes water supply valve 12 when it detects an overflow pipe water flow state (steps S8 to S10). The control operation of water supply valve 12 will be described below.

[0043] After water supply valve 12 opens, control device C monitors the water level in water supply tank 2 using overflow float sensor 22 and Hi float sensor 23 (steps S8 and S9). When water supply valve 12 opens and water is supplied from water supply pipe 10 into water supply tank 2, the water level in water supply tank 2 rises. When the water level in water supply tank 2 reaches Hi level, Hi float sensor 23 turns ON, and then when the water level in water supply tank 2 reaches the overflow level, overflow float sensor 22 turns ON. The height position of Hi float sensor 23 is slightly above overflow hole 95 of overflow pipe 9, so when Hi float sensor 23 turns ON, water (excess water) in water supply tank 2 is reliably flowing from overflow hole 95 into overflow pipe 9. The height position of the overflow float sensor 22 is slightly lower than the upstream end opening 94 of the overflow pipe 9, so when the overflow float sensor 22 turns ON, the water level in the water supply tank 2 almost reaches the upstream end opening 94 of the overflow pipe 9, and the water (excess water) in the water supply tank 2 begins to flow into the overflow pipe 9 from the upstream end opening 94 as well.

[0044] In the process of controlling the operation of the water supply valve 12, the control device C determines whether the overflow float sensor 22 has been ON for a predetermined time T1 (e.g., 3 seconds) (step S8). If the overflow float sensor 22 has been ON for the predetermined time T1 ("YES" in step S8), the control device C determines that water has passed through the overflow pipe and controls the water supply valve 12 to close (step S10). If the overflow float sensor 22 has not been ON for the predetermined time T1 ("NO" in step S8), the control device C determines whether the Hi float sensor 23 has been ON for a predetermined time T2 (e.g., 20 seconds) (step S3). If the Hi float sensor 23 has not been ON for the predetermined time T2 ("NO" in step S9), the process returns to step S8 and the control device C continues to monitor the ON state of the overflow float sensor 22. If the ON state of the Hi float sensor 23 continues for a predetermined time T2 ("YES" in step S9), the control device C determines that the overflow pipe water flow state has been detected and controls the water supply valve 12 to close (step S10).

[0045] Here, to further explain steps S8 and S9, for example, if the hot water outlet terminal 400 is unused or the usage flow rate is low, the difference between the water supply flow rate of the water supply pipe 10 and the usage flow rate of the hot water outlet terminal 400 becomes large, and the water level in the water supply tank 2 rises above the overflow level. In this case, step S8 returns "YES." On the other hand, if all hot water outlet terminals 400 are being used at maximum capacity, the difference between the water supply flow rate of the water supply pipe 10 and the usage flow rate of the hot water outlet terminal 400 becomes small. Furthermore, if water is drained from the overflow hole 95 of the overflow pipe 9, the water level in the water supply tank 2 rises above the Hi level but does not reach the overflow level. In this case, step S8 returns "NO" and step S9 returns "YES." In this way, the rise in the water level in the water supply tank 2 can be recognized regardless of the usage status of the hot water outlet terminal 400. Therefore, the water supply valve 12 can be reliably closed even if the water level in the water supply tank 2 does not reach the overflow level. If the answer to step S9 is "NO", this means that the water supply is in the initial stage and the water level in the water supply tank 2 has not yet reached the Hi water level.

[0046] By closing the water supply valve 12 through the above process, the water supply pipe 10 is closed, the water supply to the water supply tank 2 is stopped, and one cycle of the anti-freeze operation for the overflow pipe 9 is completed. After the water supply valve 12 is closed, the control device C transitions the process to step S2. As a result, the anti-freeze operation for the overflow pipe 9 from step S2 to step S10 continues unless the outside air temperature P becomes equal to or higher than the stop temperature B ("NO" in step S5).

[0047] (Effects of the embodiment) As described above, according to this embodiment, when water is supplied from water supply pipe 10 into water supply tank 2 by opening water supply valve 12 during anti-freeze operation of overflow pipe 9, water supply valve 12 remains open until the overflow pipe water flow state is detected ("NO" in step S8, "NO" in step S9). This allows water to be supplied not only into water supply tank 2 but also into water supply tank 2 until excess water flows into overflow pipe 9 and the overflow pipe water flows into trap section 92, thereby enabling water to continue to be supplied.

[0048] That is, in step S8, the control device C keeps water supply valve 12 open while the ON state of overflow float sensor 22 (detection state of the overflow water level) does not continue for the predetermined time T1 ("NO" in step S8), and if the ON state continues for the predetermined time T1 ("YES" in step S8), it determines that the overflow pipe water flow state has been detected and closes water supply valve 12 (step S10). As a result, when water is supplied from water supply pipe 10 to water supply tank 2 by opening water supply valve 12, water supply valve 12 remains open for the predetermined time T1 even if the water level in water supply tank 2 reaches the overflow water level. Therefore, within this predetermined time T1, excess water in water supply tank 2 flows from upstream end opening 94 into overflow pipe 9 and passes through trap section 92. Here, the predetermined time T1 is set to, for example, the time from when the overflow float sensor 22 detects that the water level has reached the overflow level until the overflow pipe 9 is in an overflow pipe flow state where excess water flowing into the overflow pipe 9 passes through the trap section 92. Therefore, excess water can be reliably introduced into the overflow pipe 9 and passed through the trap section 92, and freezing of water in the trap section 92 can be reliably prevented.

[0049] Furthermore, if the ON state of overflow float sensor 22 does not continue for the predetermined time T1 ("NO" in step S8), in step S9, control device C keeps water supply valve 12 open while the ON state of Hi float sensor 23 (detection state of Hi water level) does not continue for the predetermined time T2 ("NO" in step S9), and if the ON state continues for the predetermined time T2 ("YES" in step S9), it determines that the overflow pipe water flow state has been detected and closes water supply valve 12 (step S10). As a result, when water is supplied from water supply pipe 10 to water supply tank 2 by opening water supply valve 12, water supply valve 12 remains open for the predetermined time T2 even if the water level in water supply tank 2 reaches Hi water level. Therefore, during this predetermined time T2, excess water in water supply tank 2 flows from overflow hole 95 into overflow pipe 9 and passes through trap section 92. The overflow hole 95 is located between the trap portion 92 and the upstream end opening 94 and is positioned lower than the upstream end opening 94. Therefore, even if the water level in the water supply tank 2 does not reach the upstream end opening 94 of the overflow pipe 9 because, for example, water in the water supply tank 2 is used at a hot water outlet or the like and is flowing out of the water supply tank 2, excess water in the water supply tank 2 can flow from the overflow hole 95 to the overflow pipe 9. Here, the predetermined time T2 is set to, for example, the time from when the Hi float sensor 23 detects that the Hi water level has been reached until the excess water flowing from the overflow hole 95 into the overflow pipe 9 reaches the overflow pipe flow state, causing the excess water to flow through the trap portion 92. Therefore, even if the water level in the water supply tank 2 does not reach the upstream end opening 94 of the overflow pipe 9, excess water can reliably flow into the overflow pipe 9 through the overflow hole 95 and pass through the trap portion 92, thereby reliably preventing water from freezing in the trap portion 92. Furthermore, during the anti-freeze operation of the overflow pipe 9, water is supplied into the water supply tank 2, which also prevents the water in the water supply tank 2 from freezing. Furthermore, if the time that the water supply valve 12 is closed is within the determination time K ("NO" in step S4), the water supply valve 12 is not opened, which prevents unnecessary anti-freeze operation.

[0050] In the processing operation of step S8, the water supply valve 12 is closed if the ON state of the overflow float sensor 22 continues for the predetermined time T1. In other words, since the condition for closing the water supply valve 12 requires the "continuation" of the predetermined time T1, it can be assumed that the water level in the water supply tank 2 is reliably at or above the overflow level during this predetermined time T1. For example, if the water supply valve 12 is closed after the "elapse" of the predetermined time T1 from when the overflow float sensor 22 turns ON, even if the water surface in the water supply tank 2 ripples due to water falling from the outlet of the water supply pipe 10 and the overflow float sensor 22 turns ON temporarily, because the predetermined time T1 is measured from the ON time, this may include a state in which the water level in the water supply tank 2 has not yet reached the overflow level within this predetermined time T1, i.e., a state in which excess water has not yet flowed into the overflow pipe 9 from the upstream end opening 94 of the overflow pipe 9. Therefore, the predetermined time T1 that serves as the closing condition for the water supply valve 12 is set to the duration of the ON state of the overflow float sensor 22, and during this predetermined time T1, the water level in the water supply tank 2 is higher than the overflow water level, and it can be assumed that excess water is flowing reliably from the upstream end opening 94 into the overflow pipe 9.

[0051] In the present invention, the condition for closing water supply valve 12 is not limited to "continuing" for the predetermined time T1, but may be configured to keep water supply valve 12 open for at least the predetermined time T1 after overflow float sensor 22 detects ON, and then close water supply valve 12 after the predetermined time T1 has elapsed, or may be configured to close water supply valve 12 if overflow float sensor 22 detects ON both when it first detects ON and when the predetermined time T1 has elapsed. Even in such cases, depending on the configuration of the water level detection means, it can be assumed that the water level in water supply tank 2 has exceeded the overflow level during the predetermined time T1.

[0052] The significance of the above-mentioned predetermined time T1 is the same when the water supply valve 12 is closed if the ON state of the Hi float sensor 23 "continues" for the predetermined time T2 in step S9.

[0053] Furthermore, the predetermined time T2 is set to be longer than the predetermined time T1. For example, when the difference between the water supply flow rate of the water supply pipe 10 and the water usage flow rate of the hot water outlet terminal 400 is large, the water level in the water supply tank 2 exceeds the upstream end opening 94 of the overflow pipe 9, allowing a large amount of water to flow into the overflow pipe 9 from the upstream end opening 94 in a short period of time. On the other hand, when the difference between the water supply flow rate of the water supply pipe 10 and the water usage flow rate of the hot water outlet terminal 400 is small, the water level in the water supply tank 2 does not reach the upstream end opening 94 of the overflow pipe 9 but exceeds the overflow hole 95, and water flows into the overflow pipe 9 from the overflow hole 95. However, the amount of water flowing in from the overflow hole 95 is set to be less than the amount of water flowing in from the upstream end opening 94. Therefore, by setting the predetermined time T2 to be longer than the predetermined time T1, a sufficient amount of water can flow into the overflow pipe 9 from the overflow hole 95 within the predetermined time T2.

[0054] The present invention is not limited to the above-described embodiment, and various modifications can be made within the scope of the claims. For example, the water supply pipe 10 may be branched into two or more branch pipes at the downstream portion where it connects to the water supply tank 2, and connected to the water supply tank 2, with a water supply valve 12 provided on each of the branched water supply pipes 10. Moreover, the overflow float sensor 22 may be disposed at the same height as the upstream end opening 94 of the overflow pipe 9. Even in this case, when the overflow float sensor 22 is turned ON, it can reliably detect that excess water in the water supply tank 2 has begun to flow into the upstream end opening 94 of the overflow pipe 9. Furthermore, the Hi float sensor 23 may be disposed at the same height as the overflow hole 95 of the overflow pipe 9 or at a height slightly lower than the overflow hole 95. Even in this case, when the Hi float sensor 23 is turned ON, it can detect whether excess water in the water supply tank 2 has started to flow into the overflow hole 95 of the overflow pipe 9 or is just about to start flowing in. Moreover, the overflow pipe 9 does not have to be provided with the overflow hole 95. [Explanation of symbols]

[0055] 1 Hot water pressure tank unit 2 water tanks 3 Water supply pipe 6. Hot water tank 9 Overflow pipe 10 Water supply pipe 11 Governor 12 Water supply valve 21 Drain 22 Overflow float sensor (overflow water level detection means) 23 Hi float sensor (Hi water level detection means) 24 Low float sensor 25 Low water level float sensor 31 First water supply pipe 32 Second water supply pipe 33 Check valve 34 Check valve 35 Pressure Sensor 36 Water volume sensor 37 Water supply pressure pump (pump) 38 Water supply branch pipe 39 Check valve 80 Outside air temperature sensor (outside air temperature detection means) 91 Rising part 92 Trap section 93 Pipe Club 94 Upstream end opening 95 Overflow hole 200 Drain pipe 400 Hot water terminal 500 Heat source unit A Hot Water System C Control device R Remote Control

Claims

1. A heating source; a hot water storage tank for storing hot water heated by a heating heat source; a water supply tank for storing water from a water supply source; a pump that supplies hot water from the hot water storage tank and water from the water supply tank to the hot water outlet terminal; a water supply pipe that supplies water from a water supply source to a water supply tank; a water supply valve for opening and closing the water supply pipe; an overflow pipe for draining excess water in the water supply tank when the water level in the water supply tank exceeds a predetermined height; A trap section is provided in the middle of the overflow pipe and collects and seals a portion of the water flowing in the overflow pipe. an outside air temperature detection means for detecting an outside air temperature; a control device that controls anti-freeze operation, The control device, as an anti-freeze operation for the overflow pipe, opens the water supply valve when a predetermined judgment time has elapsed while the water supply valve is closed when the outside air temperature detected by the outside air temperature detection means is below a predetermined threshold temperature, and keeps the water supply valve open until it detects an overflow pipe water-passing state in which excess water flows into the overflow pipe and passes through the trap section, and controls the water supply valve to close when it detects the overflow pipe water-passing state.

2. The hot water supply system according to claim 1, the overflow pipe has an upstream end opening that communicates with the water supply tank and into which excess water in the water supply tank flows; an overflow water level detection means is provided for detecting when the water level in the water supply tank reaches a predetermined overflow water level at which excess water in the water supply tank flows into the overflow pipe from the upstream end opening; In this hot water supply system, when a predetermined time (T1) has elapsed after the overflow water level detection means detects that the overflow water level has been reached, the control device determines that the overflow pipe is in a flowing state and closes the water supply valve.

3. 3. The hot water supply system according to claim 1, The overflow pipe has an upstream end opening at its upper end, which communicates with the water supply tank and into which excess water from the water supply tank flows, and an overflow hole is provided between the upstream end opening and the trap section in addition to the upstream end opening, which communicates with the water supply tank and into which excess water from the water supply tank flows, a high water level detection means for detecting when the water level in the water supply tank reaches a predetermined high water level at which excess water in the water supply tank flows into the overflow pipe from the overflow hole; In a hot water supply system, when a predetermined time (T2) has elapsed after the Hi water level detection means detects that the Hi water level has been reached, the control device determines that the overflow pipe is in a water flowing state and closes the water supply valve.

Images