Efficient return valve and water circulation system applying same

Abstract

An efficient return valve comprises a tubular valve body, and the valve body comprises a hot water conveying pipe and a cold water conveying pipe. The device further comprises a partition wall, and a backflow through hole is formed in the partition wall. The temperature sensing elastic piece can be switched between a contraction state and an extension state according to the water temperature in the conveying pipeline, when the temperature of the temperature sensing elastic piece is lower than the deformation temperature, the temperature sensing elastic piece is in the contraction state, the temperature sensing elastic piece is separated from the sealing plug, and the sealing plug is in the extension state. The compression spring can drive the sealing plug to close the backflow through hole, and at the moment, water in the hot water conveying pipe can push away the sealing plug to flow to the cold water conveying pipe through the backflow through hole. When the temperature of the temperature sensing elastic piece is higher than the deformation temperature, the temperature sensing elastic piece is in an extension state, the temperature sensing elastic piece and the compression spring drive the sealing plug to close the backflow through hole together, and water in the hot water conveying pipe is prevented from flowing to the cold water conveying pipe through the backflow through hole.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of bathroom products, in particular to an efficient backflow valve and a water circulation system using the same. BACKGROUND

[0002] In our daily life, water heater water supply system is the choice of many families, by installing a set of water heater can provide hot water for multiple rooms, very convenient. But in practical application, due to the long hot water pipeline, part of which is exposed to the external environment for a long time, after a period of time, the hot water in the hot water pipeline will be cool, if the hot water is needed at this time, the faucet needs to be opened and the cool hot water in the hot water pipe needs to be discharged. During the process of discharging the cool water, since the time when the hot water arrives is unknown, it is generally necessary to constantly explore with hands or discharge part of the hot water. This way not only wastes water resources, but also wastes energy.

[0003] In order to solve the above problems, people have invented a zero cold water water supply system. For example, a hot water recirculation system is disclosed in Chinese patent CN109563936B. Hot water tank generates hot water by heating straight water flowing into the straight water supply pipe. The recirculation pump pressurizes the hot water flowing through the hot water discharge pipe to make it recirculate. The hot water supply pipe is connected to the outlet of the recirculation pump, and then the hot water is supplied to the water tap. The straight water supply pipe is connected to the straight water pipe, and then the straight water is supplied to the water tap. The hot water recirculation valve is provided between the hot water supply pipe and the straight water supply pipe. The hot water recirculation valve includes a housing and a pressure plate. The housing is provided with a recirculation flow path. When the hot water is recirculated, the pressure plate is pushed open by the pressure of the recirculated hot water. The hot water flows back to the hot water tank through the straight water inflow pipe. However, this hot water recirculation system generally controls the working time of the recirculation pump to realize the circulation heating time of the water. In order to ensure that the hot water can flow to the hot water recirculation valve, a longer circulation heating time is generally set, which means that too much water in the waterway is heated, and part of the useless heating will cause energy waste.

[0004] In order to further improve the utilization rate of energy, people have improved the hot water recirculation system, such as the Chinese invention patent with the publication number CN112283947A discloses a zero cold water supply system, which comprises a circulating pump, a hot water pipe, a cold water pipe and an H valve constituting a circulating waterway, the H valve communicates the hot water pipe and the cold water pipe, further comprising a temperature detector and a controller, the temperature detector is arranged at the water outlet end of the hot water pipe, the temperature detector is used for detecting the water temperature of the water outlet end of the hot water pipe, and the controller is used for controlling the temperature detector and the circulating pump to work when receiving the zero cold water control instruction. The temperature detector comprises a temperature probe and a control board, one end of the temperature probe is inserted into the H valve, and the other end is connected with the signal end of the control board, the control board is signal connected with the controller, and the circulating pump and the temperature detector stop working when the water temperature is greater than the preset water temperature. This new water supply system can stop heating in time, only half of the pipe needs to be heated, and the waste of energy is reduced. However, the improved hot water recirculation system needs to add temperature probe and control board and other electrical connecting parts in the H valve, which makes the structure of the valve body more complex and the manufacturing cost higher on the one hand, and on the other hand, since the distance between the H valve and the water heater is far, the signal connection is easy to be disturbed and unstable. SUMMARY

[0005] In order to overcome at least one of the problems of complex structure, unstable signal connection and high manufacturing cost in the prior art, the present application provides a high-efficiency backflow valve, which comprises a valve body in the form of a pipe, the valve body comprises a hot water conveying pipe and a cold water conveying pipe connected together; a partition wall is arranged at the connection of the hot water conveying pipe and the cold water conveying pipe, and a backflow through hole communicating the hot water conveying pipe and the cold water conveying pipe is arranged on the partition wall; further comprising a temperature-sensitive elastic element and a sealing plug arranged in the valve body, the sealing plug is arranged in the cold water conveying pipe, the temperature-sensitive elastic element can switch between the contracted state and the elongated state according to the water temperature in the conveying pipe, and further comprising a compression spring, the compression spring is arranged in the valve body and arranged in the same direction with the temperature-sensitive elastic element; when the temperature of the temperature-sensitive elastic element is lower than the deformation temperature, the temperature-sensitive elastic element is in the contracted state, the temperature-sensitive elastic element is separated from the sealing plug, and the compression spring can drive the sealing plug to close the backflow through hole, but at this time the water in the hot water conveying pipe can push away the sealing plug to flow to the cold water conveying pipe through the backflow through hole; when the temperature of the temperature-sensitive elastic element is higher than the deformation temperature, the temperature-sensitive elastic element is in the elongated state, the temperature-sensitive elastic element drives the sealing plug to close the backflow through hole together with the compression spring, so as to prevent the water in the hot water conveying pipe from flowing to the cold water conveying pipe through the backflow through hole.

[0006] The valve body is a water delivery component used to connect hot water pipes, cold water pipes, and water terminals (such as faucets). Its structure can be varied. In one embodiment, the valve body is an integrally formed tubular component, and the hot water delivery pipe and the cold water delivery pipe are two parts of the pipe body. In another embodiment, the hot water delivery pipe and the cold water delivery pipe are two independent pipe sections that can be detachably connected together.

[0007] The hot water delivery pipe has a hollow structure and includes a hot water inlet and a hot water outlet. The hot water inlet is located at the free end away from the cold water delivery pipe, and the hot water outlet is located on the side wall of the hot water delivery pipe near the partition wall. The axes of the hot water inlet and the hot water outlet are perpendicular to each other. The cold water delivery pipe is coaxial with the hot water delivery pipe. Similarly, the cold water delivery pipe also has a hollow structure and includes a cold water inlet and a cold water outlet. The cold water outlet is located on the side wall of the cold water delivery pipe, and the axes of the cold water inlet and the cold water outlet are perpendicular to each other.

[0008] The sealing plug is a sealing component that is movably arranged in the cold water delivery pipe and is made of a soft material, such as silicone rubber or plastic.

[0009] The compression spring is a helical elastic component with a fixed elastic coefficient. Its elastic force is proportional to the length of the compression and contraction. The compression spring is generally made of metal. In the technical solution of this invention, the compression spring can continuously apply force to the sealing plug to close the return flow hole. However, the closing force of the compression spring is less than the opening force applied to the sealing plug by the circulating water pump in the system. When the positive pressure difference formed by the water in the pipe in the opening direction of the sealing plug reaches 0.02 MPa to 0.05 MPa, it can overcome the closing force of the compression spring, and the sealing plug can open. Thus, the water in the hot water delivery pipe can flow to the cold water delivery pipe through the return flow hole.

[0010] The temperature-sensitive elastic member is an elastic component that changes with temperature, for example, the component shortens when the temperature is low and the component extends when the temperature rises, and the extension and contraction changes are repeatable. In one embodiment, the temperature-sensitive elastic member is in the shape of a spiral spring and is made of a memory alloy, and the thermal deformation temperature of the temperature-sensitive elastic member is 20-40 DEG C. It should be noted that the temperature-sensitive elastic member has elastic deformation capability in both the extended state and the contracted state as long as there is a deformation gap between the coils, that is, the temperature-sensitive elastic member can apply pressure to other objects through elastic deformation. However, the elastic coefficient of the temperature-sensitive elastic member is set to be higher than that of the compression spring, and the temperature-sensitive elastic member can apply a greater closing force to the sealing plug than the compression spring when the temperature-sensitive elastic member is in the extended state. In order to ensure that cold water can quickly return, the temperature-sensitive elastic member is separated from the sealing plug when the temperature-sensitive elastic member is in the contracted state, which reduces the closing force on the sealing plug and provides space for the movement of the sealing plug.

[0011] Compared with the prior art, the beneficial technical effects of the present application are as follows: first, by simultaneously arranging the temperature-sensitive elastic member and the compression spring in the valve body, the compression spring can continuously apply a closing force to the sealing plug, the sealing plug can block the return flow hole when the left and right pressures are balanced, the problem of cold and hot water channeling between the delivery pipes is well reduced, and cold water can return under the set pressure range when the circulating water pump is started to open the sealing plug and achieve cold water return; when hot water flows through the temperature-sensitive elastic member, the temperature-sensitive elastic member can switch to the extended state, and under the combined action of the temperature-sensitive elastic member and the compression spring, the sealing plug is pressed against the partition wall, the pressure of the circulating water pump cannot push the sealing plug away, hot water cannot pass through the return flow hole, the water flow detected by the flowmeter becomes smaller, and the water heater and the circulating water pump stop working. It can be seen that the present technical solution does not need to install a control panel and a temperature probe on the valve body, does not need to be connected with the water heater, the structure of the valve body is simple and reliable, and there is no signal interference problem; second, the temperature-sensitive elastic member is arranged in the pipeline of the valve body and directly contacts with water, the response speed is very fast, hot water can flow into the valve body, and too much hot water can flow into the cold water delivery pipe, that is, the problem of invalid heating is reduced, and energy saving is achieved; third, the sealing plug is arranged in the cold water pipe, and when hot water is used alone, the pressure at the end of the cold water delivery pipe is slightly greater than the pressure at the end of the hot water delivery pipe, at this time, the sealing plug can close the return flow hole by relying on the water pressure, and the problem of cold water channeling is well reduced.

[0012] Due to the above advantages of the high-efficiency backflow valve, the high-efficiency backflow valve can be applied to a water circulation system, which comprises a cold water source, a three-way valve, a heating device, a circulating water pump and the high-efficiency backflow valve connected together through water conveying pipes, wherein the cold water source is connected to a water inlet end of the heating device and a cold water conveying pipe of the high-efficiency backflow valve through the three-way valve respectively, a water outlet end of the heating device is connected to a hot water conveying pipe of the high-efficiency backflow valve, the circulating water pump is arranged upstream or downstream of the heating device, and the circulating water pump can make hot water in the heating device flow to the high-efficiency backflow valve through the water conveying pipes; cold water in the water conveying pipes can push the sealing plug to flow back to the heating device through the backflow through hole; when hot water in the water conveying pipes flows to the position of the temperature-sensitive elastic member, the temperature-sensitive elastic member is switched to an elongated state when the temperature of the temperature-sensitive elastic member is higher than a deformation temperature, the temperature-sensitive elastic member drives the sealing plug to close the backflow through hole to prevent hot water from flowing back to the conveying pipe; and the water circulation system further comprises a controller and a flow sensor connected to the controller, the flow sensor is used for detecting water flow in the water conveying pipes, the flow sensor can send a stop signal to the controller when the water flow in the water conveying pipes is reduced to a set value, and the controller can control the circulating water pump and the heating device to stop working after receiving the stop signal sent by the flow sensor.

[0013] Due to the above characteristics and advantages of the high-efficiency backflow valve, the high-efficiency backflow valve and the water circulation system to which the high-efficiency backflow valve is applied can be provided. BRIEF DESCRIPTION OF DRAWINGS

[0014] Figure 1 is a schematic diagram of a water circulation system to which the high-efficiency backflow valve is applied;

[0015] Figure 2 is a schematic diagram of a structure of the high-efficiency backflow valve in an axial direction;

[0016] Figure 3 is a schematic diagram of an exploded structure of the high-efficiency backflow valve;

[0017] Figure 4 is a schematic diagram of a cross-sectional structure of the high-efficiency backflow valve, showing that the temperature-sensitive elastic member is in an elongated state;

[0018] Figure 5 is a schematic diagram of a cross-sectional structure of the high-efficiency backflow valve, showing that the temperature-sensitive elastic member is in a contracted state;

[0019] Figure 6 is a schematic diagram of a cross-sectional structure of the high-efficiency backflow valve, showing that the sealing plug is in an open state. DETAILED DESCRIPTION

[0020] The high-efficiency backflow valve 2 and the water circulation system using the same will be further described in combination with the accompanying drawings. Except for the explicitly described equivalent or alternative embodiments, the various embodiments disclosed below can be selectively applied or combined in one embodiment even if there is no direct correlation or synergy in function.

[0021] As shown in Figure 1 Fig. 1 is a schematic diagram of a water circulation system, which comprises a cold water source 10, a three-way valve 11, a heating device 12 (i.e. a water heater), a circulating water pump 13 and a high-efficiency backflow valve 2 connected together through water delivery pipes. The water delivery pipes can be divided into hot water pipes 14 and cold water pipes 15 according to the connection position and the temperature of the delivered water. The cold water source 10 is connected to the water inlet end of the heating device 12 and the cold water delivery pipe 31 of the high-efficiency backflow valve 2 through the three-way valve 11, respectively. Here, the pipes connecting the cold water source 10, the three-way valve 11 and the high-efficiency backflow valve 2 are cold water pipes 15, and part of the cold water pipes 15 are used as backflow pipes. The water outlet end of the heating device 12 is connected to the hot water delivery pipe 32 of the high-efficiency backflow valve 2 through the hot water pipes 14. The circulating water pump 13 is arranged upstream or downstream of the heating device 12. The circulating water pump 13 drives the water in the pipes to flow, so that the hot water in the heating device 12 flows to the high-efficiency backflow valve 2 through the hot water pipes 14. The cold water in the hot water pipes 14 can open the high-efficiency backflow valve 2 to flow back to the heating device 12 along the cold water pipes 15. Further, in order to prevent the backflow water from flowing to the cold water source 10, a one-way check valve is arranged between the cold water source 10 and the three-way valve 11.

[0022] The following will be described in combination with Figures 2-6The high-efficiency backflow valve 2 comprises a tubular valve body 3, which comprises a hot water delivery pipe 32 and a cold water delivery pipe 31 connected together; a partition wall 4 is arranged at the connection of the hot water delivery pipe 32 and the cold water delivery pipe 31, and a backflow through hole 40 is arranged on the partition wall 4 to communicate the hot water delivery pipe 32 and the cold water delivery pipe 31; a temperature-sensitive elastic element 5 and a sealing plug 6 are arranged in the valve body 3, the sealing plug 6 is arranged in the cold water delivery pipe 31, the temperature-sensitive elastic element 5 can switch between a contracted state and an elongated state according to the water temperature in the delivery pipe, and a compression spring 7 is arranged in the valve body 3 and arranged in the same direction as the temperature-sensitive elastic element 5; when the temperature of the temperature-sensitive elastic element 5 is lower than the deformation temperature, the temperature-sensitive elastic element 5 is in the contracted state and is separated from the sealing plug 6, the compression spring 7 can drive the sealing plug 6 to close the backflow through hole 40, but at this time the water in the hot water delivery pipe 32 can push away the sealing plug 6 to flow to the cold water delivery pipe 31 through the backflow through hole 40; when the temperature of the temperature-sensitive elastic element 5 is higher than the deformation temperature, the temperature-sensitive elastic element 5 is in the elongated state and drives the sealing plug 6 to close the backflow through hole 40 together with the compression spring 7, thereby preventing the water in the hot water delivery pipe 32 from flowing to the cold water delivery pipe 31 through the backflow through hole 40.

[0023] In the embodiment, the valve body 3 is an integrally formed tubular member, the hot water delivery pipe 32 and the cold water delivery pipe 31 are two parts of the pipe body, and the partition wall 4 is transversely arranged at the connection of the hot water delivery pipe 32 and the cold water delivery pipe 31. Of course, in other equivalent embodiments, the valve body 3 can also be two separate pipe bodies of the hot water delivery pipe 32 and the cold water delivery pipe 31 which are detachably connected together. Arranging the sealing plug 6 in the cold water pipe, when hot water is used alone, the pressure at the end of the cold water delivery pipe 31 will be slightly greater than the pressure at the end of the hot water delivery pipe 32, at this time the sealing plug 6 can be closed by relying on the water pressure to reduce the problem of cold and hot water cross-flow.

[0024] The hot water delivery pipe 32 is a hollow structure, including a hot water inlet 33 arranged at the free end away from the cold water delivery pipe 31, and a hot water outlet 34 arranged on the side wall of the hot water delivery pipe 32 near one end of the partition wall 4, and the axis of the hot water inlet 33 and the hot water outlet 34 is arranged vertically. The cold water delivery pipe 31 and the hot water delivery pipe 32 are coaxially arranged, and the cold water delivery pipe 31 is also a hollow structure, including a cold water inlet 35 and a cold water outlet 36 arranged on the side wall of the cold water delivery pipe 31, and the axis of the cold water inlet 35 and the cold water outlet 36 is arranged vertically. From the cross-sectional view, the water flow passages of the hot water delivery pipe 32 and the cold water delivery pipe 31 are both L-shaped.

[0025] The compression spring 7 is a spiral elastic member with a fixed elastic coefficient, and its elastic force is proportional to the length of the extrusion contraction. The compression spring 7 is generally made of metal material. The compression spring 7 can continuously apply force to the sealing plug 6 to make the sealing plug 6 close the backflow hole 40, but the closing force of the compression spring 7 is smaller than the opening force applied to the sealing plug 6 by the circulating water pump 13 in the system. When the positive pressure difference of the water in the pipe in the opening direction of the sealing plug 6 reaches 0.02 Mpa ~ 0.05 Mpa, the closing force of the compression spring 7 can be overcome, the sealing plug 6 can be opened, and the water in the hot water delivery pipe 32 can flow to the cold water delivery pipe 31 through the backflow hole 40.

[0026] The temperature-sensitive elastic member 5 is an elastic member that changes with temperature. When the temperature is low, the member shortens, and when the temperature rises, the member elongates, and this stretching and contracting change is repeatable. In this embodiment, the temperature-sensitive elastic member 5 is in the shape of a spiral spring and is made of memory alloy, and the thermal deformation temperature of the temperature-sensitive elastic member 5 is 20℃ ~ 40℃. Whether in the elongated state or the contracted state, as long as there is a deformation gap between the coils of the temperature-sensitive elastic member 5, the temperature-sensitive elastic member 5 has elastic deformation ability, i.e. it can apply pressure to other objects through elastic deformation. However, the elastic coefficient of the temperature-sensitive elastic member 5 is set to be higher than that of the compression spring 7, and the temperature-sensitive elastic member 5 can apply a greater closing force to the sealing plug 6 than the compression spring 7 when in the elongated state. In order to ensure that the cold water can quickly backflow, the temperature-sensitive elastic member 5 is separated from the sealing plug 6 when in the contracted state, which reduces the closing force on the sealing plug 6 and provides space for the movement of the sealing plug 6. In addition, the temperature-sensitive elastic member 5 is arranged in the pipeline of the valve body 3 and directly contacts the water, and the response speed is very fast, which not only ensures that hot water flows into the valve body 3, but also reduces the flow of excessive hot water into the cold water delivery pipe 31, i.e. reduces invalid heating, and achieves energy saving.

[0027] The benefits of simultaneously arranging the temperature-sensitive elastic member 5 and the compression spring 7 in the valve body 3 are that the compression spring 7 can continuously apply a closing direction force to the sealing plug 6, so that the sealing plug 6 can block the backflow through hole 40 when the left and right pressures are substantially balanced, thereby reducing the problem of water leakage between the hot and cold water pipes, and when the circulating water pump 13 is started, the cold water backflow can open the sealing plug 6 within a set pressure range, thereby realizing cold water backflow; when hot water flows through the temperature-sensitive elastic member 5, the temperature-sensitive elastic member 5 can switch to an elongated state, and under the combined action of the temperature-sensitive elastic member 5 and the compression spring 7, the sealing plug 6 is pressed against the partition wall 4, so that the pressure of the circulating water pump 13 cannot push away the sealing plug 6, and hot water cannot pass through the backflow through hole 40; the flowmeter detects that the water flow is small, and the water heater and the circulating water pump 13 stop working. It can be seen that the technical solution does not need to install a control panel and a temperature probe on the valve body 3, nor does it need to be connected with the water heater, and the valve body 3 is simple and reliable in structure and has no signal interference problem.

[0028] In combination Figure 1 In the water circulation system, when hot water in the hot water pipeline 14 flows to the position of the temperature-sensitive elastic member 5, the temperature-sensitive elastic member 5 switches to an elongated state when the temperature is higher than the deformation temperature, the temperature-sensitive elastic member 5 drives the sealing plug 6 to close the backflow through hole 40, thereby preventing hot water from backflowing to the cold water pipeline 15. The water circulation system further comprises a controller 16 and a flow sensor 17 connected to the controller 16, the flow sensor 17 is used to detect the water flow in the water pipeline, and when the flow sensor 17 detects that the water flow in the water pipeline decreases to a set value, it can send a stop signal to the controller 16, and the controller 16 can control the circulating water pump 13 and the heating device 12 to stop working after receiving the stop signal from the flow sensor 17.

[0029] Further, the high-efficiency backflow valve 2 further comprises a connecting shaft 8, the connecting shaft 8 is movably arranged in the valve body 3 along the axial direction, one end of the connecting shaft 8 is connected to the sealing plug 6, and the other end of the connecting shaft 8 is connected to the temperature-sensitive elastic member 5 and / or the compression spring 7, and the temperature-sensitive elastic member 5 can drive the connecting shaft 8 and the sealing plug 6 to move together.

[0030] In this embodiment, the connecting shaft 8 and the temperature-sensitive elastic member 5 are arranged in the cold water pipeline 31, one end of the connecting shaft 8 is provided with a shaft hole 81, part of the temperature-sensitive elastic member 5 extends into the shaft hole 81, and a shaft cover 37 is further included, the shaft cover 37 is detachably connected to the port of the cold water pipeline 31 and can limit the outward movement of the temperature-sensitive elastic member 5 and the connecting shaft 8.

[0031] Further, the connecting shaft 8 is provided with at least one shaft body water hole 82, which is communicated with the shaft hole 81 so as to allow water to pass. The advantage of such arrangement is that water must flow through the shaft hole 81 and the shaft body water hole 82 of the connecting shaft 8, which can guide hot water to flow through the temperature-sensitive elastic member 5 when the hot water backflows, and can allow cold water to directly impact the connecting shaft 8 when the cold water is normally discharged, so as to push the connecting shaft 8 and the sealing plug 6 to move towards the backflow hole 40.

[0032] Further, in the axial view, the projection area of the connecting shaft 8 is not less than the projection area of the backflow hole 40. Such arrangement is considered that when the hot water outlet 34 and the cold water outlet 36 are opened at the same time, the water pressure in the hot water conveying pipe 32 and the cold water conveying pipe 31 is basically the same, but the water pressure on the connecting shaft 8 and the sealing plug 6 is different due to the different areas, according to the pressure principle, the side with larger area bears more force, which makes the connecting shaft 8 and the sealing plug 6 pressed by the water pressure towards the backflow hole 40, which is beneficial to reduce the cold and hot water crossflow.

[0033] Further, it further comprises a middle shaft ring 91, the outer periphery of the middle shaft ring 91 is fixedly connected in the cold water conveying pipe 31, and the middle segment region of the connecting shaft 8 is inserted into the middle shaft ring 91. The middle shaft ring 91 not only can improve the axial movement stability of the connecting shaft 8, but also can be used to support the compression spring 7.

[0034] Further, it further comprises a filter screen 92, which is arranged at the cold water inlet 35. This can reduce the influence of sand and debris in the water pipe on the temperature-sensitive elastic member 5 and the compression spring 7, and improve the working stability and service life of the efficient backflow valve 2.

Claims

1. A high-efficiency backflow valve comprising a valve body in the shape of a pipe, said valve body comprising a hot water delivery pipe and a cold water delivery pipe connected to each other; a partition wall is provided at the connection of said hot water delivery pipe and said cold water delivery pipe, and a backflow through hole is provided on said partition wall to communicate said hot water delivery pipe and said cold water delivery pipe; characterized in that, The temperature-sensitive elastic member is arranged in the valve body, and the sealing plug is arranged in the cold water delivery pipe. The temperature-sensitive elastic member can switch between a contracted state and an elongated state according to the water temperature in the delivery pipe. The temperature-sensitive elastic member and the sealing plug are separated when the temperature-sensitive elastic member is below the deformation temperature, and the compression spring can drive the sealing plug to close the backflow through hole. However, at this time, the water in the hot water delivery pipe can push the sealing plug to flow to the cold water delivery pipe through the backflow through hole. When the temperature-sensitive elastic member is above the deformation temperature, the temperature-sensitive elastic member and the compression spring drive the sealing plug to close the backflow through hole, thereby preventing the water in the hot water delivery pipe from flowing to the cold water delivery pipe through the backflow through hole.

2. The high-efficiency backflow valve according to claim 1, wherein The connecting shaft is movably arranged in the valve body in the axial direction. One end of the connecting shaft is connected to the sealing plug, and the other end of the connecting shaft is connected to the temperature-sensitive elastic member and / or the compression spring. The temperature-sensitive elastic member can drive the connecting shaft and the sealing plug to move together.

3. The high-efficiency backflow valve of claim 2, wherein The connecting shaft and the temperature-sensitive elastic member are arranged in the cold water delivery pipe. The connecting shaft is provided with a shaft hole at one end connected to the temperature-sensitive elastic member. Part of the temperature-sensitive elastic member extends into the shaft hole. The shaft cover is detachably connected to the port of the cold water delivery pipe and can limit the outward movement of the temperature-sensitive elastic member and the connecting shaft.

4. The high-efficiency backflow valve according to claim 3, wherein The connecting shaft is further provided with at least one shaft body water hole which communicates with the shaft hole to allow water to pass through.

5. The high-efficiency backflow valve of claim 4, wherein, In the axial direction, the projection area of the connecting shaft is not less than the projection area of the backflow through hole.

6. The high-efficiency backflow valve of claim 3, wherein The middle shaft ring is fixedly connected to the outer periphery of the cold water delivery pipe. The middle segment of the connecting shaft is inserted into the middle shaft ring.

7. The high-efficient return valve according to any one of claims 1 to 6, characterized in that The temperature-sensitive elastic member is in the shape of a spiral spring and is made of a memory alloy. The thermal deformation temperature of the temperature-sensitive elastic member is 20-40°C.

8. The high-efficient return valve according to any one of claims 1-6, wherein, The hot water delivery pipe includes a hot water inlet and a hot water outlet. The hot water outlet is arranged on the side wall of the hot water delivery pipe. The axes of the hot water inlet and the hot water outlet are arranged vertically. The cold water delivery pipe includes a cold water inlet and a cold water outlet. The cold water outlet is arranged on the side wall of the cold water delivery pipe. The axes of the cold water inlet and the cold water outlet are arranged vertically. The hot water delivery pipe and the cold water delivery pipe are coaxially arranged.

9. The high-efficiency backflow valve of claim 8, wherein, The filter screen is arranged at the cold water inlet.

10. A water recycling system characterised by, The high-efficiency backflow valve according to any one of claims 1-9, wherein the cold water source is connected to the inlet of the heating device and the cold water delivery pipe of the high-efficiency backflow valve through the three-way valve, the outlet of the heating device is connected to the hot water delivery pipe of the high-efficiency backflow valve, the circulating water pump is arranged upstream or downstream of the heating device, and the circulating water pump can make the hot water in the heating device flow to the high-efficiency backflow valve through the water delivery pipe; the cold water in the water delivery pipe can push the sealing plug to flow back to the heating device through the backflow through hole; when the hot water in the water delivery pipe flows to the position of the temperature-sensitive elastic element, the temperature-sensitive elastic element is switched to the elongated state when the temperature of the temperature-sensitive elastic element is higher than the deformation temperature, the temperature-sensitive elastic element drives the sealing plug to close the backflow through hole to prevent the hot water from flowing back to the delivery pipe; and the controller and the flow sensor connected to the controller are further included, the flow sensor is used to detect the water flow in the water delivery pipe, the flow sensor can send a stop signal to the controller when the water flow in the water delivery pipe is reduced to a set value, and the controller can control the circulating water pump and the heating device to stop working after receiving the stop signal sent by the flow sensor.

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