CN114484013A

CN114484013A - Water return valve and water supply system

Info

Publication number: CN114484013A
Application number: CN202011266269.6A
Authority: CN
Inventors: 巴喜亮; 梁国荣
Original assignee: Midea Group Co Ltd; Wuhu Midea Kitchen and Bath Appliances Manufacturing Co Ltd
Current assignee: Midea Group Co Ltd; Wuhu Midea Kitchen and Bath Appliances Manufacturing Co Ltd
Priority date: 2020-11-12
Filing date: 2020-11-12
Publication date: 2022-05-13

Abstract

The invention discloses a water return valve and a water supply system. The water return valve comprises a valve body, a one-way valve, a first elastic piece and a temperature control component, wherein the valve body is provided with a first flow passage, a second flow passage and a third flow passage; a check valve movably installed in the third flow passage to block the third flow passage at an initial position; the first elastic piece enables the one-way valve to have a reset tendency; the temperature control assembly comprises an adjusting valve core movably arranged in the valve body, and the one-way valve is used for moving towards the direction close to the adjusting valve core when the water pressure difference between the first flow passage and the second flow passage is increased to a preset pressure difference so as to open a third flow passage; the adjusting valve core is used for moving towards the direction close to the one-way valve when the water temperature in the valve body rises to the preset temperature so as to drive the one-way valve core of the one-way valve away from the initial position to move and open the one-way valve. Therefore, the water return valve is arranged in the water path of the water supply system, and a water return water path can be formed, so that the water supply system has a zero-cold-water function.

Description

Water return valve and water supply system

Technical Field

The invention relates to the technical field of zero-cold-water supply, in particular to a water return valve and a water supply system.

Background

The water supply system, such as a water supply system of a water heater or a water supply system of a wall-mounted boiler, is used for providing water for users, and generally comprises a gas heating device (such as a gas water heater or a wall-mounted boiler), a cold water pipe, a hot water pipe, a water mixing device and a water outlet end, wherein the water outlet end is connected with the gas heating device through the cold water pipe, the hot water pipe and the water mixing device.

In the related art, in order to make the water supply system have a zero cold water function, a return valve having a check valve is generally added to the water supply system, and the return valve is connected to a cold water pipe and a hot water pipe to form a return water path in the water supply system.

Disclosure of Invention

The invention mainly aims to provide a novel water return valve for forming a water return waterway in a water supply system.

In order to achieve the above object, the present invention provides a water return valve, including:

the valve body is provided with a first flow passage, a second flow passage and a third flow passage, wherein the first flow passage and the second flow passage are arranged at intervals, and the third flow passage is communicated with the first flow passage and the second flow passage;

a check valve movably mounted within the third flow passage, the check valve blocking the third flow passage when in an initial position;

a first elastic member for giving the check valve a tendency to return to the initial position; and

the temperature control assembly comprises an adjusting valve core, the adjusting valve core is positioned on the water outlet side of the one-way valve, and the adjusting valve core is movably arranged in the valve body in the direction far away from or close to the one-way valve;

the check valve is used for moving towards the direction close to the regulating valve core when the water pressure difference between the first flow passage and the second flow passage is increased to a preset pressure difference so as to open the third flow passage; the regulating valve core is used for moving towards the direction close to the one-way valve when the water temperature in the valve body rises to a preset temperature so as to drive the one-way valve core of the one-way valve away from the initial position to move and open the one-way valve.

Optionally, the check valve comprises a valve housing having a valve bore, the check valve spool being movably disposed in the valve bore, the check valve spool closing the check valve when in a closed position and being adapted to open the check valve when moved away from the closed position in a direction away from the adjustment valve spool;

when the one-way valve is located at the initial position, an initial distance is formed between the one-way valve core and the adjusting valve core, and the initial distance is smaller than the sum of the maximum movable distance of the adjusting valve core and the maximum movable distance of the one-way valve and is larger than or equal to the maximum movable distance of the adjusting valve core.

Optionally, the first end of the check valve element extends out of the valve housing on a side facing the regulating valve element, and when the check valve is in the initial position, a distance between the first end of the check valve element and the regulating valve element is the initial distance.

Optionally, the check valve further comprises a second elastic member, two ends of the second elastic member are respectively arranged on the valve housing and the check valve core, so as to enable the check valve core to have a tendency of returning to the closed position; and/or the presence of a gas in the gas,

the check valve element comprises a main body part and a valve element convex part convexly arranged on the peripheral surface of the main body part, the main body part is movably arranged on the valve hole, the valve element convex part is positioned outside the valve casing and on one side of the valve casing far away from the adjusting valve element, and when the check valve element is in the closing position, the valve element convex part is abutted to the outer surface of the valve casing.

Optionally, the check valve further comprises a second elastic member, two ends of the second elastic member are respectively arranged on the valve housing and the check valve core, so as to make the check valve core have a tendency of returning to the closed position;

the check valve element comprises a main body part and a valve element convex part convexly arranged on the peripheral surface of the main body part, the main body part is movably arranged in the valve hole, the valve element convex part is positioned outside the valve shell and on one side of the valve shell far away from the adjusting valve element, and when the check valve element is in the closed position, the valve element convex part is abutted against the outer surface of the valve shell;

the second elastic piece is a second spring, the second spring is sleeved outside the main body part, and two ends of the second spring are respectively arranged on the valve casing and the main body part, so that the one-way valve core has a tendency of resetting to the closed position.

Optionally, the second spring is a conical spring, a limiting groove is formed in the outer peripheral surface of the main body portion, and one end of the second spring is arranged in the limiting groove.

Optionally, the temperature control assembly further includes a valve core sleeve, the valve core is sleeved in the third flow passage, and the regulating valve core is movably arranged in the valve core sleeve;

the first elastic piece is a first spring, the first spring is sleeved outside the one-way valve, and two ends of the first spring are respectively arranged on the one-way valve and the valve core sleeve, so that the one-way valve has a tendency of resetting to the initial position.

Optionally, an inner support is arranged on the inner wall surface of the valve core sleeve, the inner support is provided with an installation through hole, the first end of the regulating valve core is slidably installed in the installation through hole, the first end of the one-way valve core is slidably installed in the installation through hole, and the first end of the first spring is arranged on the inner support.

Optionally, the installation through hole is a stepped hole and includes an installation large hole and an installation small hole, the first end of the regulating valve core is slidably installed in the installation large hole, and the first end of the one-way valve core is slidably installed in the installation small hole.

Optionally, a first water passing structure is arranged on the valve core sleeve, and/or a second water passing structure is arranged on the regulating valve core, and/or a water passing gap is formed between the outer peripheral surface of the regulating valve core and the inner wall surface of the valve core sleeve.

Optionally, a gear convex portion is convexly provided on an outer circumferential surface of a valve housing of the check valve, the first spring is located on one side of the gear convex portion facing the adjusting valve element, and one end of the first spring is located on the gear convex portion.

Optionally, a sealing ring bulge is formed on an inner wall surface of the third flow passage, and when the one-way valve is in the initial position, the gear bulge abuts against the sealing ring bulge;

the check valve further comprises a sealing ring, the sealing ring is installed on one side, far away from the adjusting valve core, of the gear convex portion, and when the check valve is located at the initial position, the sealing ring is clamped between the seal ring convex portion and the gear convex portion so as to block a third flow passage.

Optionally, the gear protrusions are distributed at intervals in the circumferential direction of the valve housing to open the third flow passage when the check valve leaves the initial position; or the gear convex part is an annular convex part, and a water through hole is formed in the gear convex part so as to open the third flow channel when the one-way valve leaves the initial position; and/or the presence of a gas in the gas,

a water passing gap is formed between the end face of the gear convex part and the inner wall face of the third flow channel, so that the third flow channel is opened when the one-way valve leaves the initial position.

Optionally, the temperature control assembly further includes a temperature control driving assembly, the temperature control driving assembly is installed in the valve body, and the temperature control driving assembly is configured to drive the adjustment valve element to move toward the direction close to the one-way valve when the temperature of the water in the valve body rises to a preset temperature.

Optionally, the temperature control driving assembly includes an ejector rod, a temperature sensing shell and a temperature sensing medium that expands when exposed to heat, the temperature sensing shell is located on a water outlet side of the one-way valve, the ejector rod is slidably mounted in the temperature sensing shell, and the adjusting valve core is mounted at an outer end of the ejector rod; the temperature sensing medium is arranged in the temperature sensing shell and is used for expanding when the temperature of water in the valve body rises to a preset temperature so as to enable the ejector rod to extend out, so that the regulating valve core is driven to move towards the direction close to the one-way valve; the temperature sensitive medium is also adapted to contract when cooled.

The invention also proposes a water supply system comprising:

a gas heating device;

the water outlet end is connected with the gas water heater through a cold water pipe, a hot water pipe and a water mixing device; and

the water return valve has a first flow passage connected to the hot water pipe and a second flow passage connected to the cold water pipe.

Optionally, the gas heating device is a gas water heater or a gas wall-hanging stove.

The invention also proposes a water supply system comprising:

a gas heating device;

the water outlet end is connected with the gas water heater through a cold water pipe, a hot water pipe and a water mixing device;

the second flow passage of the water return valve is connected to the cold water pipe or the water inlet pipe of the fuel gas heating device; and

and one end of the water return pipe is connected to the hot water pipe, and the other end of the water return pipe is connected to the first flow channel of the water return valve.

In the invention, the water return valve is arranged in a water path of the water supply system and can form a water return water path, so that the water supply system has a zero cold water function; and the preset pressure difference is larger, so that the problem that hot water in a hot water pipe or a return water pipe of a water supply system is easy to flow into a cold water pipe through a return valve when pressurized and delivered hot water can be solved.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the structures shown in the drawings without creative efforts.

FIG. 1 is a schematic structural diagram of a unified embodiment of a water supply system according to the present invention;

FIG. 2 is a schematic structural view of another embodiment of the water supply system of the present invention;

FIG. 3 is a schematic structural diagram of a water return valve according to an embodiment of the present invention;

FIG. 4 is a schematic structural diagram of the water return valve in FIG. 3 in a cold circulation state;

FIG. 5 is a schematic structural diagram of the water return valve in FIG. 3 in a hot circulation state;

FIG. 6 is a schematic structural diagram of the water return valve in FIG. 3 in a hot pressurized state;

FIG. 7 is an exploded view of the water return valve of FIG. 3;

FIG. 8 is a schematic view of the check valve of FIG. 7;

fig. 9 is a schematic diagram of the regulator valve cartridge of fig. 7.

The reference numbers illustrate:

the implementation, functional features and advantages of the objects of the present invention will be further explained with reference to the accompanying drawings.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be obtained by a person skilled in the art without inventive step based on the embodiments of the present invention, are within the scope of protection of the present invention.

It should be noted that if the description of "first", "second", etc. is provided in the embodiment of the present invention, the description of "first", "second", etc. is only for descriptive purposes and is not to be construed as indicating or implying relative importance or implicitly indicating the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature.

In addition, the meaning of "and/or" appearing throughout is to include three juxtapositions, exemplified by "A and/or B" including either scheme A, or scheme B, or a scheme in which both A and B are satisfied.

The invention provides a water return valve and a water supply system.

As shown in fig. 1 and 2, the water return valve 100 is used in a water supply system 1000, that is, the water supply system 1000 includes the water return valve 100, so that the water supply system 1000 has a zero-cold-water function, so as to realize a timed cruise function and a heat preservation function. The water return valve 100 will be described in detail below with reference to the structure of a water supply system 1000, and optionally, the water supply system 1000 is a water supply system 1000 of a water heater (including but not limited to a gas water heater system) or a water supply system 1000 of a wall-hanging stove, etc., and the gas water heater system is taken as an example for description below.

In an embodiment of the present invention, as shown in fig. 1 and 2, the water supply system 1000 further includes a gas heating device 200, a cold water pipe 300, a hot water pipe 400, a water mixing device 600, a water outlet 700, a water return valve 100, and the like, wherein the water outlet 700 is connected to the gas heating device 200 through the cold water pipe 300, the hot water pipe 400, and the water mixing device 600; the return valve 100 is installed in a water path of the water supply system 1000 to form a return water path for providing the water supply system 1000 with a zero-cold water function.

Specifically, as shown in fig. 1 and 2, the gas heating device 200 has a cold water inlet 201 and a hot water outlet 202, and the water mixing device 600 has a hot water inlet, a cold water inlet, and a water mixing outlet.

Wherein, one end of the cold water pipe 300 and the cold water inlet 201 are both connected (i.e. communicated) with a water supply pipe (such as a tap water pipe, etc.), and the other end of the cold water pipe 300 is communicated with a cold water inlet; one end of the hot water pipe 400 is communicated with the hot water outlet 202, the other end is communicated with the hot water inlet, and the mixed water outlet is communicated with the water outlet end 700. Thus, the mixing device 600 can be adjusted to allow the outlet end 700 to deliver cold water alone or mixed hot water at an appropriate temperature.

Optionally, a cold water joint is arranged at the cold water inlet 201; and/or a hot water joint is arranged at the hot water outlet 202.

Optionally, the water supply system 1000 includes a water inlet pipe 210, the cold water inlet 201 is communicated with a water supply pipe through the water inlet pipe 210, and the cold water pipe 300 is communicated with the water inlet pipe 210.

Optionally, the water outlet end 700 may be a shower or a faucet.

Optionally, the water outlet end 700 may be provided in plurality.

Optionally, the mixing device 600 is a mixing valve or other mixing device 600 with similar function to the mixing valve.

Alternatively, the gas heating device 200 may be a gas water heater, a wall-mounted gas stove, or the like, and the following description will be given taking the gas water heater as an example.

In one embodiment of the present invention, as shown in fig. 3 to 9, the water return valve 100 includes a valve body 10, a check valve 20, a first elastic member 50, and a temperature control member 30.

Specifically, as shown in fig. 3 to 9, the valve body 10 has a water path channel, and the water path channel includes a first channel 11 and a second channel 12 that are arranged at an interval, and a third channel 13 that communicates the first channel 11 with the second channel 12.

Specifically, as shown in fig. 3 to 9, the check valve 20 is movably installed in the third flow passage 13, and the check valve 20 blocks the third flow passage 13 in the initial position.

Optionally, the check valve 20 is used to guide the water in the first flow channel 11 into the second flow channel 12 in a single direction.

Specifically, as shown in fig. 3-9, the first elastic member 50 is used to make the check valve 20 have a tendency to return to the initial position, so that the check valve 20 is always in the initial position. Specifically, the first elastic member 50 is disposed in the waterway flow passage.

Specifically, as shown in fig. 3 to 9, the temperature control assembly 30 includes an adjusting valve core 31, the adjusting valve core 31 is located at the water outlet side of the check valve 20, and the adjusting valve core 31 is movably disposed in the valve body 10 in a direction away from or close to the check valve 20.

Specifically, as shown in fig. 3 to 9, the check valve 20 is configured to move toward the direction close to the regulating valve core 31 when the water pressure difference between the first flow passage 11 and the second flow passage 12 increases to a preset pressure difference, so as to open the third flow passage 13; the regulating valve core 31 is used for moving towards the direction close to the one-way valve 20 when the temperature of the water in the valve body 10 rises to the preset temperature so as to drive the one-way valve core 21 of the one-way valve 20 away from the initial position to move and open the one-way valve 20.

Specifically, the check valve 20 includes a valve housing 22 having a valve hole, and the check valve body 21 is movably provided to the valve hole to open or close the check valve 20 by one end of the check valve body 21.

In particular, the check valve spool 21 has a closed position closing the check valve 20, i.e. the check valve spool 21 closes the check valve 20 when in the closed position. And when the check valve body 21 moves away from the closed position, the check valve 20 can be opened. In the present embodiment, the check valve spool 21 is used to open the check valve 20 when moved away from the closed position in a direction away from the regulator valve spool 31.

The check valve 20 is a normally closed switch, and when the check valve 20 is closed, water in the first flow passage 11 cannot flow to the second flow passage 12 through the check valve 20; after the check valve 20 is opened, the water in the first flow passage 11 can flow to the second flow passage 12 through the check valve 20.

It will be appreciated that when the one-way valve 20 is in the initial position and the one-way valve 20 is closed, the third flow passage 13 may be blocked to prevent water in the first flow passage 11 from flowing to the second flow passage 12. However, when the check valve 20 is moved away from the initial position and/or the check valve 20 is opened, the third flow channel 13 is opened, and the water in the first flow channel 11 can flow to the second flow channel 12 through the third flow channel 13.

In this embodiment, when the check valve 20 is in the initial position, an initial distance exists between the check valve spool 21 and the regulating valve spool 31, and the initial distance is smaller than the sum of the maximum movable distance of the regulating valve spool 31 and the maximum movable distance of the check valve 20 and is greater than or equal to the maximum movable distance of the regulating valve spool 31, so as to realize that: the regulating valve core 31 is used for moving towards the direction close to the one-way valve 20 when the temperature of the water in the valve body 10 rises to a preset temperature so as to drive the one-way valve core 21 of the one-way valve 20 away from the initial position to move and open the one-way valve 20.

Specifically, when the check valve 20 moves in a direction to approach the regulator spool 31, the check spool 21 can be moved to the movement locus of the regulator spool 31. In this way, by making the initial distance greater than or equal to the maximum movable distance of the regulator spool 31, it is possible to prevent the regulator spool 31 from driving the check spool 21 of the check valve 20 located at the initial position to move in a direction to approach the check valve 20, and thus, from opening the check valve 20 by mistake. And by making the initial spacing smaller than the sum of the maximum movable distance of the regulator spool 31 and the maximum movable distance of the check valve 20, the regulator spool 31 can drive the check valve spool 21 of the check valve 20 away from the initial position to move when moving in a direction approaching the check valve 20, so as to open the check valve 20.

Alternatively, the initial spacing is equal to the maximum movable distance of the regulator spool 31.

Of course, in other embodiments, the "adjusting valve core 31 is configured to move toward the one-way valve 20 when the temperature of the water in the valve body 10 rises to the preset temperature, so as to drive the one-way valve core 21 of the one-way valve 20 away from the initial position to move, so as to open the one-way valve 20", for example, a transmission structure (such as a lever structure) may be added between the adjusting valve core 31 and the one-way valve core 21.

The function of the return valve 100 will be described in detail below in conjunction with the structure of the different water supply system 1000.

In an embodiment of the water supply system 1000, the water supply system 1000 is not provided with the water return pipe 500; as shown in fig. 1, the first flow passage 11 is connected to the heat exchange pipe, the second flow passage 12 is connected to the cold water pipe 300, and when the outlet end 700 has a plurality of flow passages, the return valve 100 is optionally provided at the most distal outlet end 700.

Specifically, one end (e.g., end B in fig. 1) of the first flow passage 11 is communicated with the hot water inlet through a hot water pipe 400, and the other end (e.g., end a in fig. 1) of the first flow passage 11 is communicated with the hot water outlet 202 through the hot water pipe 400; one end (e.g., end C in fig. 1) of the second flow passage 12 is communicated with the cold water inlet through a cold water pipe 300, and the other end (e.g., end D in fig. 1) of the second flow passage 12 is communicated with the water inlet pipe 210 through the cold water pipe 300. Thus, a backwater water path may be formed among the hot water pipe 400, the first flow path 11, the third flow path 13 and/or the fourth flow path, the second flow path 12, the cold water pipe 300, the water inlet pipe 210, the gas heating apparatus 200, and the like, and the backwater valve 100 may be disposed in the backwater water path.

Of course, the above water return valve 100 may also be used in the water supply system 1000 having the water return pipe 500. As another embodiment of the water supply system 1000 according to the present invention, as shown in fig. 2, the water supply system 1000 includes a water return pipe 500, one end of the water return pipe 500 is connected to the hot water pipe 400, the other end is connected to one end (e.g., end a in fig. 2) of the first flow passage 11, and the other end (e.g., end B in fig. 2) of the first flow passage 11 is blocked (e.g., by an end cap).

And in this embodiment, the second flow passage 12 is connected to the water inlet pipe 210 or the cold water pipe 300.

Alternatively, as shown in fig. 2, the second flow passage 12 is connected to the water inlet pipe 210; specifically, one end (e.g., end C in fig. 2) of the second flow passage 12 is communicated with the cold water inlet 201 through the water inlet pipe 210, and the other end (e.g., end D in fig. 2) of the second flow passage 12 is communicated with the cold water pipe 300 through the water inlet pipe 210.

Optionally, the water return valve 100 is disposed near the gas heating apparatus 200.

And in this embodiment, when the outlet end 700 has a plurality of parts, the water return pipe 500 is connected to the farthest outlet end 700.

Thus, a return water path may be formed between the hot water pipe 400, the return pipe 500, the first flow passage 11, the third flow passage 13 and/or the fourth flow passage, the second flow passage 12, the inlet pipe 210, and the heat exchanger of the gas heating apparatus 200, etc.; wherein the water return valve 100 is arranged in the water return waterway.

Specifically, for the above two embodiments, as shown in fig. 1 and 2, the gas heating apparatus 200 further includes a water circulating pump 800, the water circulating pump 800 is disposed in the water return waterway, and the water circulating pump 800 is configured to drive water to flow in the water return waterway. Optionally, the water circulation pump 800 is disposed between the heat exchanger of the gas heating apparatus 200 and the cold water inlet 201, so that the water circulation pump 800 can also be used for sucking cold water and/or pressurizing and delivering water, etc.

Specifically, as shown in fig. 4, when the water supply system 1000 in the above two embodiments performs the circulation preheating by using the zero cold water function, the circulation water pump 800 pushes water in the return water path to flow, so that the water pressure in the first flow channel 11 is increased, and thus the difference between the water pressure in the first flow channel 11 and the water pressure in the second flow channel 12 is increased; when the water pressure difference between the first flow passage 11 and the second flow passage 12 is increased to a preset pressure difference, the check valve 20 moves towards the direction close to the regulating valve core 31 and leaves the initial position to open the third flow passage 13, so that the water in the first flow passage 11 can flow into the second flow passage 12 through the third flow passage 13, the water circularly flows in the water return waterway, and the water in the hot water pipe 400 and the like can be circularly preheated. At this time, as shown in fig. 4, the return valve 100 is in the cold circulation state, and the check valve body 21 of the check valve 20 is located on the movement locus of the regulator valve body 31.

Referring to fig. 5, when the temperature of the water in the hot water pipe 400 or the water return pipe 500 rises to a certain temperature but does not reach the expected preheating temperature (e.g. 100), and the temperature of the water in the valve body 10 (i.e. in the water path flow passage, specifically at the temperature control element 30) rises to a preset temperature, the regulating valve element 31 moves toward the check valve 20, and during the movement, the regulating valve element 31 acts (e.g. abuts against or acts through a transmission structure) with the check valve element 21 of the check valve 20 away from the initial position to drive the check valve element 21 to move (i.e. away from the closed position) so as to open the check valve 20. Therefore, the circulation preheating can be continuously carried out, and the flow in the circulation water channel can be increased so as to increase the preheating speed. At this time, as shown in fig. 5, the return valve 100 is in a thermal cycle state.

Referring to fig. 6, when the water outlet end 700 is hot and pressurized (i.e. hot water is pressurized), the water circulating pump 800 is used to pressurize to increase the water outlet amount and the water outlet speed, and due to the characteristic curve of the water pump, when the water pump is just turned on, the water pressure in the first flow channel 11 will increase rapidly, i.e. the water pressure difference between the first flow channel 11 and the second flow channel 12 will increase; however, when the water outlet end 700 has a larger water flow rate after being opened, the pressure difference between the water inlet and the water outlet of the circulating water pump 800 will decrease, that is, the pressure difference between the first flow passage 11 and the second flow passage 12 will decrease.

According to the above, the first elastic member 50 is designed to make the preset pressure difference larger, so that the check valve 20 is prevented from moving away from the initial position when the hot water is pressurized and delivered, and the effect of preventing water from flowing when the hot water is pressurized and delivered is achieved. At this time, as shown in fig. 6, the return valve 100 is in the hot state pressurized state.

Further, since "the regulating valve body 31 moves in a direction approaching the check valve 20 when the temperature of the water in the valve body 10 rises to the preset temperature to drive the check valve body 21 of the check valve 20 away from the initial position to move to open the check valve 20", that is, the preset differential pressure is increased, the circulation warming can be continued.

It should be noted that the preset pressure difference may be adjusted by adjusting the elastic parameter of the first elastic member 50 itself or the initial elastic value of the first elastic member 50 when the check valve 20 is at the initial position.

Therefore, in the present invention, the water return valve 100 is installed in a water path of the water supply system 1000, and a water return path can be formed, so that the water supply system 1000 has a zero cold water function; in addition, the preset pressure difference can be increased, so that the problem that the hot water in the hot water pipe 400 or the return pipe 500 of the water supply system 1000 is easy to flow into the cold water pipe 300 through the return valve 100 when the hot water is pressurized and delivered can be solved.

Meanwhile, optionally, the opening threshold of the check valve 20 may be made larger to avoid the check valve 20 being opened by mistake when the cold water is pressurized.

Further, as shown in fig. 3 to 9, a first end of the check valve spool 21 protrudes from a side of the valve housing 22 facing the adjustment valve spool 31, and when the check valve 20 is in the initial position, a distance between the first end of the check valve spool 21 and the adjustment valve spool 31 is the initial distance.

In this way, the first end of the check valve body 21 is extended out of the valve housing 22 so that the regulator valve body 31 can abut against the check valve body 21.

Of course, in other embodiments, one end of the regulator spool 31 may extend into the valve housing 22 to abut against the check spool 21, or the like.

Further, as shown in fig. 3 to 9, the check valve 20 further includes a second elastic member 23, and two ends of the second elastic member 23 are respectively disposed on the valve housing 22 and the check valve core 21, so as to make the check valve core 21 have a tendency to return to the closed position. In this manner, the check valve 20 can be placed in a normally closed state.

Further, as shown in fig. 3 to 9, the check valve element 21 includes a main body portion 211 and a valve element protrusion 212 protruding from an outer peripheral surface of the main body portion 211, the main body portion 211 is movably disposed in the valve hole, the valve element protrusion 212 is disposed outside the valve housing 22 and on a side of the valve housing 22 away from the adjustment valve element 31, and when the check valve element 21 is in the closed position, the valve element protrusion 212 abuts against an outer surface of the valve housing 22.

Thus, the check valve body 21 is restrained at the closed position, and the check valve body 21 is allowed to open the check valve 20 when leaving the closed position in a direction away from the regulating valve body 31.

Specifically, the valve body protrusion 212 abuts against the peripheral edge of the valve hole.

Further, as shown in fig. 3 to 9, the second elastic member 23 is a second spring. Thus, the structure can be simplified conveniently, and the performance of the spring is more stable, thereby improving the reliability. Of course, in other embodiments, the second elastic member 23 may be provided with other elastic members such as an elastic pressing sheet, a rubber band, or a pressing band.

Specifically, as shown in fig. 3 to 9, the second spring is sleeved outside the main body portion 211, and two ends of the second spring are respectively disposed on the valve housing 22 and the main body portion 211, so that the check valve element 21 has a tendency of returning to the closed position. Alternatively, the second spring is located on the side of the spool protrusion 212 facing the regulator spool 31.

In this way, not only the movement stability of the check valve body 21 can be improved, but also the space occupied in the movement direction of the check valve body 21 can be reduced.

Further, as shown in fig. 3 to 9, the second spring is a conical spring, a limiting groove is formed on the outer circumferential surface of the main body portion 211, and one end of the second spring is disposed in the limiting groove.

Specifically, a stopping step is formed on the inner wall surface of the valve hole, and the other end of the conical spring abuts against the stopping step.

Of course, in other embodiments, a limiting ring protrusion may be disposed on the inner wall surface of the valve hole to cooperate with the valve core protrusion 212 to achieve limiting and sealing.

Further, as shown in fig. 3 to 9, the temperature control assembly 30 further includes a valve core sleeve 36, the valve core sleeve 36 is disposed in the third flow channel 13, and the regulating valve core 31 is movably disposed in the valve core sleeve 36.

Specifically, the valve core sleeve 36 is fixedly installed in the third flow channel 13, and the regulating valve core 31 is slidably disposed in the valve core sleeve 36.

Further, as shown in fig. 3 to 9, two ends of the first elastic element 50 are respectively disposed on the check valve 20 and the valve core sleeve 36, so that the check valve 20 has a tendency to return to the initial position.

Specifically, as shown in fig. 3 to 9, the first elastic member 50 is a first spring. Thus, the structure can be simplified conveniently, and the performance of the spring is more stable, thereby improving the reliability.

Further, as shown in fig. 3 to 9, the first spring is sleeved outside the check valve 20, and two ends of the first spring are respectively disposed on the check valve 20 and the valve core sleeve 36, so that the check valve 20 has a tendency of returning to the initial position.

Specifically, the first spring sleeve is sleeved outside the valve housing 22, and two ends of the first spring are respectively disposed on the valve housing 22 and the valve core sleeve 36, so that the check valve 20 has a tendency of returning to the initial position.

In this way, not only the movement stability of the check valve 20 can be improved, but also the space occupied in the movement direction of the check valve 20 can be reduced.

Of course, in other embodiments, the first elastic member 50 may be provided with other elastic members such as an elastic pressing sheet, a rubber band, or a pressing band.

In a specific embodiment, in order to prevent the valve core sleeve 36 and the regulator valve core 31 from blocking the third flow channel 13, a first water passing structure may be provided on the valve core sleeve 36, and/or a second water passing structure may be provided on the regulator valve core 31, and/or a water passing gap may be formed between an outer circumferential surface of the regulator valve core 31 and an inner wall surface of the valve core sleeve 36, and/or a through flow gap may be provided between an inner wall surface of the third flow channel 13 and the valve core sleeve 36, and so on. The second water passing structure provided on the regulating valve core 31 will be described as an example.

Further, an inner support 361 is disposed on an inner wall surface of the valve core sleeve 36, the inner support 361 has a mounting through hole 3611, a first end (i.e., an end facing the check valve 20) of the regulator valve core 31 is slidably mounted in the mounting through hole 3611, and a first end of the first spring is disposed on the inner support 361.

In this way, on the one hand, the stability of the movement of the control valve disk 31 can be increased, and on the other hand, the arrangement of the first spring is also facilitated.

It will be appreciated that the inner support 361 has water passing holes.

Further, as shown in fig. 3 to 9, a first end of the check valve spool 21 is slidably installed in the installation through hole 3611. Therefore, on one hand, the stability of the movement of the check valve core 21 can be improved, and on the other hand, the adjustment valve core 31 can drive the check valve core 21 to move conveniently.

Specifically, the check valve body 21 further includes a guide portion 213 disposed at one end of the main body portion 211 (i.e., the end facing the adjustment valve body 31), and the guide portion 213 is slidably mounted in the mounting through hole 3611. The guide portion 213 forms a first end of the check valve body 21.

Further, as shown in fig. 3 to 9, the installation through hole 3611 is a stepped hole and includes an installation large hole and an installation small hole, the first end of the adjustment valve core 31 is slidably installed in the installation large hole, and the first end of the check valve core 21 is slidably installed in the installation small hole.

Specifically, the guide 213 is slidably mounted in the mounting hole.

In this way, by making the mounting through hole 3611 a stepped hole, at least the movement of the regulator valve body 31 can be restricted.

Further, as shown in fig. 3 to 9, the main body portion 211 and the guide portion 213 form a step structure, so as to be at least used for limiting the movement of the check valve body 21.

Further, as shown in fig. 3 to 9, a gear protrusion 221 is protruded from an outer circumferential surface of the valve housing 22, the first spring is located on a side of the gear protrusion 221 facing the adjustment valve element 31, and one end of the first spring is located on the gear protrusion 221. Specifically, one end of the first spring abuts against the shift protrusion 221.

Thus, the two elastic ends of the first spring are respectively abutted against the convex part 221 and the inner support 361, so that the first spring is in a compressed state, and the check valve 20 has a tendency of returning to the initial position.

Further, as shown in fig. 3 to 9, a sealing ring protrusion 131 is formed on an inner wall surface of the third flow passage 13, and the shift protrusion 221 abuts against the sealing ring protrusion 131 when the check valve 20 is at the initial position. In this way, the check valve 20 can be restrained at the initial position.

Further, as shown in fig. 3 to 9, the check valve 20 further includes a sealing ring 24, the sealing ring 24 is mounted on a side of the gear protrusion 221 away from the regulator valve core 31, and when the check valve 20 is in the initial position, the sealing ring 24 is sandwiched between the sealing ring protrusion 131 and the gear protrusion 221 to block the third flow channel 13.

Alternatively, the gear protrusion 221 is provided at an end of the valve housing 22 away from the regulator valve core 31.

Further, as shown in fig. 3 to 9, the gear protrusions 221 are distributed at intervals in the circumferential direction of the valve housing 22 to open the third flow passages 13 when the check valve 20 leaves the initial position; or, the gear convex part 221 is an annular convex part, and a water through hole is formed in the gear convex part 221 so as to open the third flow channel 13 when the check valve 20 leaves the initial position; and/or the presence of a gas in the atmosphere,

a water passing gap is provided between an end surface of the shift protrusion 221 and an inner wall surface of the third flow passage 13, so as to open the third flow passage 13 when the check valve 20 is away from the initial position.

In this way, it is achieved that the third flow channel 13 is opened when the non-return valve 20 leaves the initial position.

In this embodiment, the plurality of gear protrusions 221 are spaced apart from each other in the circumferential direction of the valve housing 22, a water passing space is formed between two adjacent gear protrusions 221, and an annular protrusion formed by the plurality of gear protrusions 221 is slidably installed in the third flow channel 13 to improve the movement stability of the valve housing 22.

Of course, in other embodiments, a sealing convex portion may be protruded on the circumferential surface of the valve housing 22 and on the side of the gear convex portion 221 away from the adjustment valve core 31 to be matched with the sealing ring convex 131.

Further, as shown in fig. 3 to 9, when the check valve body 21 is in the closed position, the seal ring 24 is interposed between the valve body convex portion 212 and the valve housing 22 to close the check valve 20.

Of course, in other embodiments, another sealing ring 24 may be additionally disposed on the valve core convex portion 212 to close the check valve 20.

Specifically, as shown in fig. 3 to 9, the temperature control assembly 30 further includes a temperature control driving assembly 32, the temperature control driving assembly 32 is installed in the valve body 10 (i.e., in the waterway channel), and the temperature control driving assembly 32 is configured to drive the regulating valve core 31 to move toward the check valve 20 when the temperature of the water in the valve body 10 (i.e., in the waterway channel) rises to a preset temperature.

Further, as shown in fig. 3 to 9, the temperature control driving assembly 32 includes a top rod 321, a temperature sensing shell 322 and a temperature sensing medium 323 expanding when exposed to heat, the temperature sensing shell 322 is located on the water outlet side of the one-way valve 20, the top rod 321 is slidably mounted in the temperature sensing shell 322, and the adjusting valve core 31 is mounted at the outer end of the top rod 321; the temperature sensing medium 323 is arranged in the temperature sensing shell 322, and the temperature sensing medium 323 is used for expanding when the temperature of the water in the water channel rises to a preset temperature so as to extend the ejector rod 321, so as to drive the regulating valve core 31 to move towards the direction close to the one-way valve 20; the temperature sensing medium 323 also serves to contract when cooled.

Specifically, the temperature sensing medium 323 expands when the temperature of the water in the valve housing 22 rises to a predetermined temperature, so that the push rod 321 can be driven to slide to extend the push rod 321; when the temperature of the water at the temperature sensing reaction part drops below a preset temperature, the temperature sensing medium 323 contracts, so that the push rod 321 can reset along with the temperature sensing medium 323 or driven by other resetting pieces.

The temperature control driving component 32 is a thermal bulb component, that is, the temperature sensing shell 322 and the temperature sensing medium 323 in the temperature sensing shell 322 form a thermal bulb, and together with the push rod 321, etc., form a thermal bulb component.

Alternatively, the temperature sensing medium 323 may be paraffin, methanol, toluene, or the like. It should be noted that the preset temperature is related to the selection of the temperature sensing medium 323, for example, when the temperature sensing medium 323 is paraffin, the preset temperature can be 37 degrees, and the like.

Further, as shown in fig. 3 to 9, the temperature controlled driving assembly 32 further includes a third elastic member 324, and the third elastic member 324 is used for making the regulating valve core 31 have a tendency of returning to the initial position. Thus, when the temperature sensing medium 323 contracts, the third elastic member 324 drives the adjustment valve body 31 to return together with the push rod 321, thereby improving the reliability and other performances of the return valve 100.

In an embodiment, the third elastic member 324 may be a spring, a spring plate, or a rubber band.

In this embodiment, as shown in fig. 3-9, the third elastic member 324 is a third spring. Thus, the structure can be simplified conveniently, and the performance of the spring is more stable, thereby improving the reliability.

Further, as shown in fig. 3 to 9, the third spring is sleeved outside the regulating valve core 31, and two ends of the third spring are respectively disposed on the inner support 361 and the regulating valve core 31, so that the regulating valve core 31 has a tendency of returning. In this way, not only the stability of the movement of the adjustment spool 31 can be improved, but also the space occupied in the direction of movement of the adjustment spool 31 can be reduced.

Further, as shown in fig. 3 to 9, the regulating valve core 31 includes a valve core main body 311 and a limit protrusion 313 protruding from a circumferential surface of the valve core main body 311, and two ends of the third spring are respectively disposed on the inner support 361 and the limit protrusion 313, so that the regulating valve core 31 has a tendency of returning.

Specifically, two ends of the third spring respectively abut against the limit convex part 313 and the inner support 361, so that the third spring is in a compressed state, and the limit valve core has a tendency of resetting.

Further, as shown in fig. 3 to 9, an end surface of one end (i.e., the end facing the second flow channel 12) of the valve core main body 311 is opened with an installation groove 314, and an outer end of the push rod 321 is installed in the installation groove 314.

Further, as shown in fig. 3 to 9, the valve body 311 is provided with a water passage hole 315 communicating with the mounting groove 314.

Specifically, the plurality of water through holes 315 are distributed at intervals in the circumferential direction of the valve body 311.

Specifically, the water passage hole 315 extends to an end surface of the valve body 311 facing one end of the second flow passage 12.

In this manner, the third flow channel 13 can be prevented from being blocked.

Further, as shown in fig. 3 to 9, the regulating valve core 31 further includes a sliding portion 312 provided at one end of the valve core body 311 (i.e., an end facing the check valve 20), and the sliding portion 312 is slidably installed in the installation through hole 3611.

Specifically, the sliding portion 312 is used to form a first end of the regulator valve core 31, i.e., the sliding portion 312 is slidably mounted in the mounting hole.

The sliding portion 312 and the valve body 311 form a step structure to limit the movement of the adjustment valve core 31.

Specifically, the end of the sliding portion 312 (i.e., the end facing the check valve 20) is used for the end of the guide portion 213 to abut against, so as to drive the movement of the check valve body 21. The distance between the end of the sliding portion 312 and the end of the guide portion 213 in the moving direction of the check valve body 21 is the initial distance.

Of course, in other embodiments, the temperature sensing driving assembly may be configured in other structural forms, for example, the temperature sensing driving assembly further includes a temperature sensing seat, and a temperature sensing elastic sheet and an elastic resetting member that are disposed on the temperature sensing seat, so that the temperature sensing elastic sheet deforms when the temperature rises to extend the adjustment valve core 31, and the elastic resetting member retracts the adjustment valve core 31; and so on.

Of course, in other embodiments, a convex structure may be provided on the inner wall surface of the third flow passage 13 to mount the first spring, the regulator valve body 31, the third spring, and the like.

Further, as shown in fig. 3 to 9, the water return valve 100 further includes a fourth elastic member 40, the temperature-controlled driving component 32 is movably disposed in the waterway channel, and the fourth elastic member 40 is configured to make the temperature-controlled driving component 32 have a tendency to move toward the direction of approaching the check valve 20. Specifically, the temperature sensing case 322 is movably disposed in the water passage, and the fourth elastic member 40 is used to make the temperature sensing case 322 tend to move toward the one-way valve 20.

The movable direction of the regulating valve core 31 and the movable direction of the temperature sensing shell 322 should be both directions approaching or departing from the one-way valve 20.

It is understood that the temperature-controlled driving assembly 32 formed by using the temperature-sensitive medium 323 such as paraffin generally has a temperature-sensing delay characteristic, i.e., after the temperature-controlled driving assembly 32 drives the check valve 20 to move to the initial position of the check valve 20 through the regulating valve core 31, the temperature-controlled driving assembly still has a tendency to drive the regulating valve core 31 to move, which may damage the regulating valve core 31.

However, in the present invention, the temperature control driving unit 32 is movably disposed in the water passage, and the fourth elastic member 40 is disposed to make the temperature control driving unit 32 tend to move toward the check valve 20, so that the adverse effect of the temperature sensing delay characteristic of the temperature sensing medium 323 such as paraffin can be eliminated.

Alternatively, as shown in fig. 3-9, the fourth elastic member 40 is a fourth spring. Specifically, the fourth spring is sleeved outside the temperature sensing shell 322, and one end of the fourth spring is connected to the inner wall surface of the water channel, and the other end of the fourth spring is connected to the temperature sensing shell 322, so that the temperature sensing shell 322 has a tendency of moving toward the direction close to the check valve 20.

Optionally, the spring constant of the third spring is less than the spring constant of the fourth spring.

Further, as shown in fig. 3 to 9, in order to improve the mounting and moving stability of the temperature control driving assembly 32, the temperature control assembly 30 further includes a supporting frame 35, the supporting frame 35 is fixedly mounted in the third flow channel 13, and the temperature control driving assembly 32 is mounted on the supporting frame 35.

Specifically, the supporting frame 35 is provided with a supporting hole, and the temperature sensing shell 322 is slidably mounted in the supporting hole, so that the temperature control driving component 32 is movably mounted in the water channel. Wherein, the support frame 35 is located on one side of the valve core sleeve 36 far away from the one-way valve 20.

Further, as shown in fig. 3 to 8, the first flow channel 11 includes a first flow section 111, one end of the first flow section 111 is provided with a first flow channel 11 port, the other end of the first flow section 111 is communicated with the third flow channel 13, and the extending direction of the first flow section 111 is the same as the extending direction of the third flow channel 13.

Optionally, a filter screen 70 is further disposed at the first flow passage 11.

Further, as shown in fig. 3 to 8, the second flow channel 12 includes a second flow segment 121, one end of the second flow segment 121 is provided with a second flow channel 12 port, the other end of the second flow segment 121 is communicated with a third flow channel 13, and an extending direction of the second flow segment 121 is the same as an extending direction of the third flow channel 13.

The temperature control assembly 30 is installed in the second flow section 121 and the third flow channel 13.

Optionally, as shown in fig. 3 to 8, the first flow segment 111, the third flow channel 13, and the second flow segment 121 are straight flow channels, and the first flow segment 111 and the second flow segment 121 are respectively disposed at two ends of the third flow channel 13.

Further, as shown in fig. 3 to 8, the first flow passage 11 further includes a third flow section 112 communicated with the first flow section 111, a communication position between the first flow section 111 and the third flow section 112 is communicated with the third flow passage 13, and one end of the third flow section 112 is provided with a port 13 of the third flow passage.

The second flow channel 12 further includes a fourth flow section 122 communicated with the second flow section 121, a communication position between the second flow section 121 and the fourth flow section 122 is communicated with the third flow channel 13, and a fourth flow channel opening is arranged at one end of the fourth flow section 122.

Of course, in other embodiments, the waterway flow passage may be designed in other structural forms, for example, the first flow passage 11, the second flow passage 12 and the third flow passage 13 may form an H-shaped structure.

Further, as shown in fig. 3 to 8, the valve core sleeve 36 is disposed in the middle section of the third flow passage 13.

Further, as shown in fig. 3 and 7, the valve body 10 includes a first valve body 10a and a second valve body 10b which are connected in a fitting manner, the first valve body 10a has a first flow passage 11 and a part of a third flow passage 13, and the second valve body 10b has a second flow passage 12 and a part of the third flow passage 13. Thus, assembly of the return valve 100 may be facilitated.

Further, as shown in fig. 3 and 7, the first valve body 10a is detachably connected to the second valve body 10 b.

Specifically, the first valve body 10a is clamped with the second valve body 10 b.

Optionally, a snap spring 60 is arranged at the clamping position of the first valve body 10a and the second valve body 10 b.

The above description is only an alternative embodiment of the present invention, and is not intended to limit the scope of the present invention, and all modifications and equivalents made by the contents of the present specification and the accompanying drawings, or directly/indirectly applied to other related technical fields, which are within the spirit of the present invention, are included in the scope of the present invention.

Claims

1. A water return valve, comprising:

2. The water return valve according to claim 1 wherein said check valve includes a valve housing having a valve opening, said check valve element being movably disposed in said valve opening, said check valve element closing said check valve when in a closed position and being adapted to open said check valve when moved away from said closed position in a direction away from said regulating valve element;

when the one-way valve is at the initial position, an initial distance is formed between the one-way valve core and the adjusting valve core, and the initial distance is smaller than the sum of the maximum movable distance of the adjusting valve core and the maximum movable distance of the one-way valve and is larger than or equal to the maximum movable distance of the adjusting valve core.

3. The water return valve according to claim 2 wherein a first end of said check valve element protrudes from a side of said valve housing facing said adjustment valve element, and a distance between said first end of said check valve element and said adjustment valve element is said initial distance when said check valve is in said initial position.

4. The water return valve according to claim 3 wherein said check valve further comprises a second elastic member, both ends of said second elastic member being provided to said valve housing and said check valve element, respectively, for providing said check valve element with a tendency to return to said closed position; and/or the presence of a gas in the gas,

5. The water return valve according to claim 4 wherein said check valve further comprises a second elastic member, both ends of said second elastic member being respectively provided to said valve housing and said check valve element for providing said check valve element with a tendency to return to said closed position;

6. The water return valve according to claim 5, wherein the second spring is a conical spring, a limiting groove is formed in an outer peripheral surface of the main body, and one end of the second spring is disposed in the limiting groove.

7. The water return valve according to any one of claims 2 to 6, wherein the temperature control assembly further comprises a valve core sleeve, the valve core is sleeved in the third flow passage, and the regulating valve core is movably arranged in the valve core sleeve;

8. The water return valve according to claim 7, wherein the inner wall surface of the spool housing is provided with an inner support having a mounting through-hole, the first end of the adjustment spool is slidably mounted in the mounting through-hole, the first end of the check spool is slidably mounted in the mounting through-hole, and the first end of the first spring is provided in the inner support.

9. The water return valve according to claim 8 wherein said mounting through-hole is a stepped hole and includes a mounting large hole in which a first end of said regulating spool is slidably mounted and a mounting small hole in which a first end of said check spool is slidably mounted.

10. The water return valve according to claim 7, wherein the valve core sleeve is provided with a first water passing structure, and/or the adjusting valve core is provided with a second water passing structure, and/or a water passing gap is formed between the outer peripheral surface of the adjusting valve core and the inner wall surface of the valve core sleeve.

11. The water return valve according to claim 7 wherein a gear protrusion is protruded from an outer circumferential surface of a valve housing of the check valve, the first spring is located on a side of the gear protrusion facing the adjustment valve body, and one end of the first spring is located on the gear protrusion.

12. The water return valve according to claim 11, wherein a seal ring protrusion is formed on an inner wall surface of the third flow passage, and the shift protrusion abuts against the seal ring protrusion when the check valve is in the initial position;

13. The water return valve according to claim 12 wherein said gear protrusions are spaced circumferentially of said valve housing to open said third flow passage when said check valve is moved away from said initial position; or the gear convex part is an annular convex part, and a water through hole is formed in the gear convex part so as to open the third flow channel when the one-way valve leaves the initial position; and/or the presence of a gas in the gas,

14. The water return valve according to any one of claims 1 through 6 wherein the thermostat assembly further comprises a thermostat drive assembly mounted within the valve body for driving the regulating valve element to move in a direction approaching the check valve when the temperature of the water within the valve body rises to a predetermined temperature.

15. The water return valve according to claim 14 wherein the temperature-controlled driving assembly includes a push rod, a temperature-sensing shell and a temperature-sensing medium that expands when exposed to heat, the temperature-sensing shell is located on the water outlet side of the one-way valve, the push rod is slidably mounted in the temperature-sensing shell, and the adjusting valve core is mounted at the outer end of the push rod; the temperature sensing medium is arranged in the temperature sensing shell and is used for expanding when the temperature of water in the valve body rises to a preset temperature so as to enable the ejector rod to extend out, so that the regulating valve core is driven to move towards the direction close to the one-way valve; the temperature sensitive medium is also adapted to contract when cooled.

16. A water supply system, comprising:

a gas heating device;

a water return valve according to any one of claims 1 to 15 having a first flow path connected to the hot water pipe and a second flow path connected to the cold water pipe.

17. The water supply system of claim 16, wherein the gas heating device is a gas water heater or a gas wall-hanging stove.

18. A water supply system, comprising:

a gas heating device;

the water return valve according to any one of claims 1 to 15, wherein a second flow passage of the water return valve is connected to a cold water pipe or a water inlet pipe of the gas heating device; and