water supply system

Abstract

The present invention provides a water supply system. The water supply system includes a water heater, a water supply pipe, a return pipe, and a drainage component. The water heater includes a water heater body, a main pipe, a heater, and a water pump. The main pipe is disposed on the water heater body, and the heater and water pump are both disposed on the main pipe. The water supply pipe includes a water supply main pipe and a water supply branch pipe that are interconnected. The return pipe connects the main pipe and the water supply main pipe. The drainage component includes a drain valve disposed at the junction of the return pipe and the main pipe. The return pipe is connected to the outside atmosphere when the drain valve is open. The water supply branch pipe returns residual water to the return pipe when the drain valve is open. The water pump sends residual water in the return pipe to the heater for heating and output to the water supply main when the drain valve is closed. The water supply system of the present invention eliminates significant unevenness in hot water temperature during use, providing a more comfortable bathing water temperature.

Description

Technical Field

[0001] The present invention relates to the technical field of household appliances, and in particular to a water supply system. Background Art

[0002] A water heater is a device that uses various physical principles to raise the temperature of cold water into hot water within a certain period of time.

[0003] As people's living standards improve, zero-cold-water gas water heaters, which provide instant hot water, have become a trend in the water heater industry. "Zero-cold-water" technology involves pumping cold water back into the main pipeline of the water heater for circulation and heating before releasing the heated hot water. This prevents the user from initially discharging a large amount of cold water when turning on the water heater.

[0004] In practical applications, preheated water typically flows through the water supply main, return pipe, and main line before returning to the water supply main to achieve circulation. However, because one end of the water supply branch pipe is closed and the other end is connected to the water supply main, water pressure and other factors prevent the water in the water supply branch pipe from being discharged into the water supply main during preheating. In other words, the circulating preheated hot water cannot flow into the water supply branch pipe. As a result, the water in the water supply branch pipe does not participate in the circulating preheating during the preheating process. When preheating is completed and the hot water tap (or water point) is opened, the water temperature in the water supply branch pipe has not been heated. Therefore, the colder water in the water supply branch pipe will mix with the preheated hot water in the water supply main, forming a section of warm water that is lower than the preset temperature. This causes unstable water temperature after opening the hot water tap. Moreover, the longer the water supply branch pipe, the greater the water pressure, the more cold water will flow into the water supply main, and the more unstable the water temperature, which directly affects the comfort of the bathing water temperature. Summary of the Invention

[0005] The purpose of the present invention is to provide a water supply system for stabilizing water temperature and improving bathing comfort.

[0006] The above-mentioned purpose of the present invention can be achieved by adopting the following technical solutions:

[0007] The present invention provides a water supply system, comprising:

[0008] The water heater comprises a water heater body, a main pipe, a heater and a water pump, wherein the main pipe is arranged on the water heater body, and the heater and the water pump are both arranged on the main pipe;

[0009] Water supply pipes, including interconnected water supply mains and water supply branches;

[0010] Return pipe, connecting the main line and the water supply main;

[0011] Drainage components, including a drain valve, which is arranged at the connection between the return pipe and the main pipe. The return pipe is connected to the external atmosphere when the drain valve is opened;

[0012] Among them, the water supply branch pipe returns the remaining water in it to the return pipe when the drain valve is opened, and the water pump sends the remaining water in the return pipe to the heater for heating and output to the water supply main when the drain valve is closed.

[0013] In an embodiment of the present invention, a drain outlet is provided at the connection between the return pipe and the main pipe. When the drain valve is opened, the return pipe is connected to the outside atmosphere through the drain outlet. The position of the drain outlet is lower than the highest point of the water supply branch pipe. The position of the drain outlet is configured so that the atmospheric pressure at the drain outlet is lower than the water pressure in the water supply branch pipe.

[0014] In an embodiment of the present invention, the drain outlet is located above the connection between the water supply main and the water supply branch pipe, and the drain outlet is located so that the atmospheric pressure at the drain outlet is greater than or equal to the water pressure at the connection between the water supply main and the water supply branch pipe.

[0015] In an embodiment of the present invention, the drainage component is provided on the water heater body and is located at the drainage port.

[0016] In an embodiment of the present invention, a water inlet valve is further included, which is arranged at the water inlet of the main pipeline, the water inlet is used to connect to the tap water pipeline, and the water inlet valve is used to open or close the water inlet;

[0017] Among them, the water supply branch pipe returns the remaining water to the return pipe when the drain valve is open and the water inlet valve is closed. The water pump sends the remaining water in the return pipe to the heater for heating and outputs it to the water supply main when the drain valve is closed and the water inlet valve is closed.

[0018] In an embodiment of the present invention, the drain valve and the water inlet valve are both solenoid valves, and the controller of the water heater is electrically connected to the heater, the drain valve and the water inlet valve respectively.

[0019] In an embodiment of the present invention, a water pressure sensor is further included, which is electrically connected to the controller and is used to detect the water pressure in the water supply main pipe, water supply branch pipe and / or return pipe; wherein,

[0020] When the water pressure sensor detects that the water pressure in the water supply main, water supply branch and / or return pipe is greater than or equal to a preset value, the controller opens the drain valve and closes the water inlet valve, so that the water supply branch pipe returns the remaining water to the return pipe;

[0021] When the water pressure sensor detects that the water pressure in the water supply main, water supply branch and / or return pipe is lower than the preset value, the controller closes the drain valve and the water inlet valve, and causes the water pump to send the remaining water in the return pipe to the heater for heating and output to the water supply main.

[0022] In an embodiment of the present invention, a one-way valve is further included, which is arranged between the drain outlet and the water inlet. The one-way valve is used to allow the drain outlet to be unidirectionally conducted toward the water inlet.

[0023] In an embodiment of the present invention, a bypass pipe is further included, through which the return pipe is connected to the main pipe, the drain valve and the one-way valve are both arranged on the bypass pipe, and the drain port and the water inlet are both opened on the bypass pipe.

[0024] In an embodiment of the present invention, a water flow sensing device is further included, which is arranged on the main line and electrically connected to the controller. The water flow sensing device is used to detect the water flow of the main line. The controller turns on the heater when the water flow sensing device detects the water flow of the main line. The controller turns off the heater when the water flow sensing device does not detect the water flow of the main line.

[0025] The characteristics and advantages of the present invention are:

[0026] The water supply system of the present invention improves the existing preheating mode and enables the return pipe to be connected to the external atmosphere. Since the water pressure in the return pipe is greater than the external atmospheric pressure, a part of the water in the return pipe is discharged from the return pipe before preheating. Since the return pipe and the water supply pipe are connected, when the water in the return pipe is discharged, the water in the water supply pipe (water supply main pipe and water supply branch pipe) will also be discharged. As a result, the water in the water supply branch pipe will be reduced or even non-existent. Therefore, the drain valve is closed and the water is circulated and preheated through the water pump and heater, so that the remaining water (water that is not discharged and remains in the return pipe and water supply pipe) is basically heated. In specific applications, for example, when the hot water faucet connected to the water supply branch pipe is turned on, the remaining water participating in the circulation preheating will be pressed into the water supply branch pipe under the action of the water pressure of the water flowing into the main line from the tap water pipe. As a result, the water coming out of the hot water faucet of the water supply branch pipe is hot water that has been circulated and heated, so the water temperature is relatively stable. That is, the water in the water supply branch pipe in the prior art that has not been circulated and heated is more than that in the water supply branch pipe of the present invention. Since at least a part of the water supply branch pipe of the present invention is discharged, the water coming out of the hot water faucet of the water supply branch pipe basically comes from the hot water of the water supply main pipe, and the water temperature is relatively stable, which can improve the comfort of bathing water temperature. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The above and other features and advantages of the present invention will become more apparent by describing in detail exemplary embodiments thereof with reference to the accompanying drawings.

[0028] Figure 1 is a schematic diagram of a water supply system of the present invention;

[0029] Figure 2 is a schematic diagram of the water supply system of the present invention in a pressure relief state;

[0030] Figure 3is a schematic diagram of the water supply system of the present invention in a preheating state;

[0031] Figure 4 is a schematic diagram of the water supply system of the present invention in standby mode;

[0032] Figure 5 Schematic diagram of the water supply system of the present invention in use.

[0033] Reference numerals and descriptions:

[0034] 1. Water heater; 11. Water heater body; 12. Main line; 13. Heater; 14. Water pump; 15. Controller;

[0035] 2. Water supply pipe; 21. Water supply main pipe; 22. Water supply branch pipe; 221. Bathing branch pipe; 222. Kitchen branch pipe;

[0036] 3. Return pipe;

[0037] 4. Drainage components; 41. Drain valve;

[0038] 5. Water inlet valve;

[0039] 6. One-way valve;

[0040] 7. Bypass pipe; 71. Drain outlet; 72. Water inlet;

[0041] 8. Water flow sensing device;

[0042] 9. Water outlet temperature sensor;

[0043] 10. Return water temperature sensor;

[0044] 101. Operate the display; 1011. Preheat key;

[0045] 102. Guide hose. DETAILED DESCRIPTION

[0046] Example embodiments will now be described more fully with reference to the accompanying drawings. However, example embodiments can be embodied in many forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete and will fully convey the concepts of the example embodiments to those skilled in the art. Like reference numerals in the figures represent like or similar structures, and thus their detailed description will be omitted.

[0047] The terms "a", "an", "the", and "said" are used to indicate the presence of one or more elements / components / etc.; the terms "including" and "having" are used to express an open-ended inclusive meaning and mean that additional elements / components / etc. may be present in addition to the listed elements / components / etc.

[0048] like Figures 1 to 5 As shown, the present invention provides a water supply system, including a water heater 1, a water supply pipe 2, a return pipe 3 and a drainage component 4. The water heater 1 includes a water heater body 11, a main line 12, a heater 13 and a water pump 14. The main line 12 is arranged on the water heater body 11, and the heater 13 and the water pump 14 are both arranged on the main line 12; the water supply pipe 2 includes a water supply main 21 and a water supply branch pipe 22 that are interconnected; the return pipe 3 connects the main line 12 and the water supply main 21; the drainage component 4 includes a drain valve 41, which is arranged at the connection between the return pipe 3 and the main line 12, and the return pipe 3 is connected to the external atmosphere when the drain valve 41 is opened; wherein, when the drain valve 41 is opened, the water supply branch pipe 22 returns the residual water therein to the return pipe 3, and when the drain valve 41 is closed, the water pump 14 sends the remaining water in the return pipe 3 to the heater 13 for heating and outputs it to the water supply main 21.

[0049] The water supply system of the present invention improves the existing preheating mode, so that the return pipe 3 can be connected to the external atmosphere. Since the water pressure in the return pipe 3 is greater than the external atmospheric pressure, Figure 2 As shown, by draining part of the water in the return pipe 3 before preheating, since the return pipe 3 and the water supply pipe 2 are connected, when the water in the return pipe 3 is drained, the water in the water supply pipe 2 (the water supply main pipe 21 and the water supply branch pipe 22) will also be drained. Figure 3 As shown, the water in the water supply branch pipe 22 will be reduced or even non-existent, so the drain valve 41 is closed and the water is circulated and preheated through the water pump 14 and the heater 13, so that the remaining water (the water that is not discharged and remains in the return pipe 3 and the water supply pipe 2) is basically heated. In specific applications, such as Figure 4 and Figure 5 As shown, for example, when the hot water faucet connected to the water supply branch pipe 22 is turned on, the remaining water participating in the circulating preheating will be pressed into the water supply branch pipe 22 under the action of the water pressure of the water flowing into the main line 12 from the tap water pipe. As a result, the water coming out of the hot water faucet of the water supply branch pipe 22 is hot water that has been heated by circulation, so the water temperature is relatively stable. That is, the water that has not been heated by circulation in the water supply branch pipe 22 in the prior art is more than that in the water supply branch pipe 22 of the present invention. Since at least a part of the water supply branch pipe 22 of the present invention is discharged, the water coming out of the hot water faucet of the water supply branch pipe 22 basically comes from the hot water of the water supply main 21, and the water temperature is relatively stable, which can improve the comfort of the bathing water temperature.

[0050] Specifically, a drain outlet 71 is provided at the connection between the return pipe 3 and the main line 12. When the drain valve 41 is opened, the return pipe 3 is connected to the outside atmosphere through the drain outlet 71. The position of the drain outlet 71 is lower than the highest point of the water supply branch pipe 22. The position of the drain outlet 71 is configured so that the atmospheric pressure of the drain outlet 71 is lower than the water pressure in the water supply branch pipe 22. Therefore, the water in the return pipe 3 can be discharged without the help of additional liquid conveying equipment such as the water pump 14, so that the water in the water supply branch pipe 22 can be discharged. The structure is simple and the cost is low.

[0051] More specifically, the position of the drain outlet 71 is larger than the connection between the water supply main 21 and the water supply branch pipe 22. The position of the drain outlet 71 is configured so that the atmospheric pressure at the drain outlet 71 is greater than or equal to the water pressure at the connection between the water supply main 21 and the water supply branch pipe 22. Through the above-mentioned structural setting, the internal and external pressures can be equalized, thereby avoiding the discharge of water from the water supply main 21 itself, that is, only the water from the water supply branch pipe 22 can be discharged to reduce the waste of water resources. In addition, in specific applications, if the water in the water supply main 21 is not filled, there is a technical problem that water from water intake points such as hot water faucets or showers will intermittently flow out or even spray out during use, affecting the user experience.

[0052] In one embodiment of the present invention, the drainage component 4 is arranged on the water heater body 11 and is located at the drain outlet 71. Through the above-mentioned structural setting, the drainage component 4 can be connected to the water heater body 11, thereby facilitating production, processing, home installation and maintenance.

[0053] Specifically, in practical applications, there are typically multiple water supply branches 22. For ease of description, two water supply branches 22 are used as an example, and for ease of description, the two water supply branches 22 are configured as a bathing branch 221 and a kitchen branch 222, respectively. In the prior art, without a drainage component 4, since the upper ends of each water supply branch 22 are sealed and the lower ends of each water supply branch 22 are connected to the main water supply pipe 21, the water stored in each water supply branch 22 cannot be drained during preheating due to factors such as water pressure differences, preventing the circulating hot water from flowing into the water supply branch 22. Consequently, the water stored in each water supply branch 22 does not participate in the circulating preheating process. When preheating is complete and the shower (or water tap) for the bathing branch 221 is turned on, the uncirculated heated water in the water supply branch 22 is ejected first. The uncirculated heated water in the kitchen branch 222 mixes with the circulating heated water in the main water supply pipe 21, forming another section of water with unstable temperature. In one embodiment, a one-way valve can be installed at the lower end of kitchen branch pipe 222. This one-way valve is used to connect the water supply main 21 to the water supply branch pipe 22. In other words, the water in kitchen branch pipe 222 cannot flow from the lower end to the upper end. This prevents the uncirculated heated water in kitchen branch pipe 222 from mixing with the circulated heated water in water supply main 21. Furthermore, if there are three water supply branch pipes 22, a one-way valve can be installed at the lower end of each of the two water supply branch pipes 22 near the water heater 1. If there are four water supply branch pipes 22, a one-way valve can be installed at the lower end of each of the three water supply branch pipes 22 near the water heater 1. Compared with the above structure, the present invention sets the drainage component 4 on the water heater body 11 and is located at the drain outlet 71. There is no need to set one or more one-way valves at the lower end of the water supply branch pipe 22, which is low in cost. Moreover, since the water supply branch pipe 22 is usually buried in the wall, it is also easy to maintain without removing the wall tiles and damaging the wall, thereby improving maintainability and maintenance efficiency.

[0054] In one embodiment of the present invention, it also includes an inlet valve 5, which is arranged at the water inlet 72 of the main line 12. The water inlet 72 is used to connect to the tap water pipe, and the inlet valve 5 is used to open or close the water inlet 72; wherein, the water supply branch pipe 22 returns the residual water therein to the return pipe 3 when the drain valve 41 is open and the inlet valve 5 is closed, thereby, the water in the return pipe 3 is only discharged through the drain valve 41, and the water pump 14 sends the remaining water in the return pipe 3 to the heater 13 for heating and outputs it to the water supply main 21 when the drain valve 41 is closed and the inlet valve 5 is closed. Thus, the water in the tap water pipe will not participate in the circulating heating, and the remaining water will not be discharged through the drain valve 41, which can save water resources, and the amount of the circulating heated water is fixed, so it will not be pressed into the water supply branch pipe 22 under the action of water pressure and become cold water.

[0055] Furthermore, the drain valve 41 and the water inlet valve 5 are both solenoid valves, and the controller 15 of the water heater 1 is electrically connected to the heater 13, the drain valve 41 and the water inlet valve 5 respectively. The above structure is set to facilitate control without manual operation by the user.

[0056] Furthermore, it also includes a water pressure sensor, which is electrically connected to the controller 15. The water pressure sensor is used to detect the water pressure in the water supply main 21, the water supply branch pipe 22 and / or the return pipe 3; wherein, when the water pressure sensor detects that the water pressure in the water supply main 21, the water supply branch pipe 22 and / or the return pipe 3 is greater than or equal to a preset value, the controller 15 opens the drain valve 41 and closes the water inlet valve 5, so that the water supply branch pipe 22 returns the residual water therein to the return pipe 3; the controller 15 closes the drain valve 41 when the water pressure sensor detects that the water pressure in the water supply main 21, the water supply branch pipe 22 and / or the return pipe 3 is less than a preset value. Valve 41 is opened and the water inlet valve 5 is closed, so that the water pump 14 sends the remaining water in the return pipe 3 to the heater 13 for heating and outputs it to the water supply main 21. Since the water supply branch pipe 22 does not participate in the circulation preheating mainly because the water pressure of the water supply branch pipe 22 is lower than the water pressure of the water supply main 21, the water in the water supply branch pipe 22 cannot flow into the water supply main 21. The present invention can determine the flow direction of water between the water supply branch pipe 22 and the water supply pipe 2 by changing the water pressure, and open or close the drain valve 41 in real time according to the change of water pressure to achieve precise drainage and pressure relief, which can not only reduce the influence of the water pressure of the water supply branch pipe 22, but also reduce the waste of water resources.

[0057] Specifically, it also includes a water flow sensing device 8, which is arranged on the main line 12 and is electrically connected to the controller 15. The water flow sensing device 8 is used to detect the water flow of the main line 12. The controller 15 turns on the heater 13 when the water flow sensing device 8 detects the water flow of the main line 12. The controller 15 turns off the heater 13 when the water flow sensing device 8 does not detect the water flow of the main line 12. In this way, not only can the heater 13 be prevented from dry burning, but also energy can be saved.

[0058] In specific applications, if the drain valve 41 is connected to the water supply branch pipe 22, the drain valve 41 (solenoid valve) not only has a technical problem of being far away from the controller 15, making it inconvenient to connect the two, but also has a technical problem of accidentally touching the water flow sensing device 8 and causing the heater 13 to be mistakenly turned on, causing the main line 12 to dry burn. The present invention sets the drain valve 41 at the connection between the return pipe 3 and the main line 12. During the drainage and pressure relief process, the water in the water supply pipe 2 first flows into the return pipe 3 and is then discharged by the drain valve 41, and almost does not flow through the water flow sensing device 8 in the water heater body 11.

[0059] In one embodiment, a guide hose 102 may also be included, the upper end of which may be connected to the drain outlet 71 and the lower end of which may be connected to the sewer, so that the water discharged from the drain outlet 71 can be directly introduced into the sewer, and the water pressure of the return pipe 3 and the water supply branch pipe 22 can be reduced to near zero water pressure.

[0060] Furthermore, it can also include an outlet water temperature sensor 9 (or it can be called an outlet water temperature probe), a return water temperature sensor 10 (or it can be called a return water temperature probe) and an operation display 101. The outlet water temperature probe is arranged near the water outlet end of the main line 12 and is electrically connected to the controller 15; the return water temperature probe is arranged near the water inlet end of the main line 12 and is electrically connected to the controller 15; the operation display 101 is arranged on the water heater body 11 and is electrically connected to the controller 15, and a preheating key 1011 for turning on the preheating function is provided on the operation display 101.

[0061] In one embodiment of the present invention, a one-way valve 6 is further included, which is arranged between the drain outlet 71 and the water inlet 72. The one-way valve 6 is used to make the drain outlet 71 unidirectional toward the water inlet 72. Therefore, when the water inlet valve 5 is opened, the tap water entering through the water inlet 72 can directly flow into the water heater 1, and the tap water entering will not flow out from the drain outlet 71, thereby further reducing the waste of water resources.

[0062] Furthermore, the bypass pipe 7 is further included. The bypass pipe 7 can be a four-way pipe (pipe fitting). The return pipe 3 is connected to the main pipe 12 through the bypass pipe 7. The drain valve 41 and the one-way valve 6 are both arranged on the bypass pipe 7. The drain port 71 and the water inlet 72 are both opened on the bypass pipe 7. That is, among the four ports of the four-way pipe, one port can be connected to the main pipe 12, one port can be the drain port 71, one port can be the water inlet 72, and one port can be connected to the other end of the return pipe 3.

[0063] Working process:

[0064] Press the preheating key 1011 on the operation display 101 to start the preheating function;

[0065] like Figure 2 As shown, the water can be drained and pressure released first, that is, the controller 15 can close the water inlet valve 5 and open the drain valve 41, so that the return pipe 3 is connected to the external atmosphere, so as to discharge the water from the water supply branch pipe 22 through the return pipe 3;

[0066] like Figure 3 As shown, when the pressure relief time (e.g., 5 to 10 seconds) is reached, the controller 15 closes the drain valve 41 and turns on the water pump 14 and the heater 13, so that the remaining water in the return pipe 3 is sent to the heater 13 for heating and then discharged to the water supply main 21 for circulation preheating;

[0067] like Figure 4As shown, when the water temperature of the return pipe 3 is greater than or equal to the preset water temperature, and / or when the heater 13 is turned on for longer than the preset time, the water pump 14 and the heater 13 are turned off to complete the preheating function and enter the standby mode;

[0068] like Figure 5 As shown, the hot water tap of the water supply branch pipe 22 is opened, the controller 15 opens the water inlet valve 5, and the tap water flowing into the water inlet 72 will press the water in the water supply main 21 into the water supply branch pipe 22 and flow out from the hot water tap.

[0069] In summary, the water supply system of the present invention has the following effects:

[0070] Since the water stored in the upper part of the water supply branch pipe 22 is heated water instead of cold water in the prior art, the water temperature of the water flowing out of the hot water faucet fluctuates little or basically does not fluctuate. Compared with the conventional zero cold water preheating method, the water supply system of the present invention will not have a large uneven hot water temperature when using water at the terminal (or water collection point), and the bathing water temperature is more comfortable.

[0071] In the embodiments of the present invention, the term "plurality" refers to two or more, unless otherwise specified. Terms such as "installed," "fixed," and "connected" should be interpreted broadly. For example, "connected" can refer to a fixed connection, a detachable connection, or an integral connection. Those skilled in the art will understand the specific meanings of these terms in the embodiments of the present invention based on specific circumstances.

[0072] In the description of the embodiments of the present invention, it should be understood that the terms "upper" and "lower" and the like indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present invention and simplifying the description, rather than indicating or implying that the device or unit referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, they cannot be understood as limitations on the embodiments of the present invention.

[0073] Throughout this specification, terms such as "one embodiment" and "a preferred embodiment" mean that the specific features, structures, materials, or characteristics described in conjunction with that embodiment or example are included in at least one embodiment or example of the present invention. In this specification, schematic representations of these terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0074] The above is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations are possible in the present invention. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A water supply system, characterized in that: include: A water heater (1) comprises a water heater body (11), a main pipe (12), a heater (13) and a water pump (14), wherein the main pipe (12) is arranged on the water heater body (11), and the heater (13) and the water pump (14) are both arranged on the main pipe (12); A water supply pipe (2), comprising a water supply main pipe (21) and a water supply branch pipe (22) that are interconnected; A return pipe (3) connecting the main pipe (12) and the water supply pipe (21); A drainage component (4) includes a drainage valve (41), wherein the drainage valve (41) is provided at the connection between the return pipe (3) and the main pipe (12), and the return pipe (3) is connected to the external atmosphere when the drainage valve (41) is opened; The water supply branch pipe (22) returns the remaining water therein to the return pipe (3) when the drain valve (41) is opened, and the water pump (14) sends the remaining water in the return pipe (3) to the heater (13) for heating and outputting the water to the water supply main pipe (21) when the drain valve (41) is closed. A drain port (71) is provided at the connection between the return pipe (3) and the main pipe (12). When the drain valve (41) is opened, the return pipe (3) is connected to the external atmosphere through the drain port (71). The position of the drain port (71) is lower than the highest point of the water supply branch pipe (22). The position of the drain port (71) is configured so that the atmospheric pressure at the drain port (71) is lower than the water pressure in the water supply branch pipe (22). The position of the drain port (71) is greater than the connection between the water supply main pipe (21) and the water supply branch pipe (22), and the position of the drain port (71) is configured so that the atmospheric pressure of the drain port (71) is greater than or equal to the water pressure at the connection between the water supply main pipe (21) and the water supply branch pipe (22); It also includes a water inlet valve (5) arranged at the water inlet (72) of the main pipeline (12), the water inlet (72) being used to connect to a tap water pipeline, and the water inlet valve (5) being used to open or close the water inlet (72); The water supply branch pipe (22) returns the residual water therein to the return pipe (3) when the drain valve (41) is open and the water inlet valve (5) is closed, and the water pump (14) sends the remaining water in the return pipe (3) to the heater (13) for heating and outputting the water to the water supply main pipe (21) when the drain valve (41) is closed and the water inlet valve (5) is closed.

2. The water supply system according to claim 1, wherein: The drainage component (4) is arranged on the water heater body (11) and is located at the drainage port (71).

3. The water supply system according to claim 1, wherein: The drain valve (41) and the water inlet valve (5) are both solenoid valves, and the controller (15) of the water heater (1) is electrically connected to the heater (13), the drain valve (41) and the water inlet valve (5), respectively.

4. The water supply system according to claim 3, characterized in that It also includes a water pressure sensor electrically connected to the controller (15), the water pressure sensor is used to detect the water pressure in the water supply main (21), the water supply branch pipe (22) and / or the return pipe (3); wherein, The controller (15) opens the drain valve (41) and closes the water inlet valve (5) when the water pressure sensor detects that the water pressure in the water supply main pipe (21), the water supply branch pipe (22) and / or the return pipe (3) is greater than or equal to a preset value, so that the water supply branch pipe (22) returns the residual water to the return pipe (3); The controller (15) closes the drain valve (41) and the water inlet valve (5) when the water pressure sensor detects that the water pressure in the water supply main (21), the water supply branch pipe (22) and / or the return water pipe (3) is less than the preset value, so that the water pump (14) sends the remaining water in the return water pipe (3) to the heater (13) for heating and outputting the water to the water supply main (21).

5. The water supply system according to claim 4, characterized in that It also includes a one-way valve (6) disposed between the drain port (71) and the water inlet (72), the one-way valve (6) being used to allow the drain port (71) to flow in a one-way manner toward the water inlet (72).

6. The water supply system according to claim 5, wherein: It also includes a bypass pipe (7), the return pipe (3) is connected to the main pipe (12) through the bypass pipe (7), the drain valve (41) and the one-way valve (6) are both arranged on the bypass pipe (7), and the drain port (71) and the water inlet (72) are both opened on the bypass pipe (7).

7. The water supply system according to claim 3, wherein: The device further comprises a water flow sensing device (8), which is arranged on the main pipe (12) and is electrically connected to the controller (15). The water flow sensing device (8) is used to detect the water flow of the main pipe (12). The controller (15) turns on the heater (13) when the water flow sensing device (8) detects the water flow of the main pipe (12). The controller (15) turns off the heater (13) when the water flow sensing device (8) does not detect the water flow of the main pipe (12).

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