Control method of zero-cold-water water supply system, zero-cold-water water supply system and h-shaped water valve

Abstract

This invention relates to the field of gas water heater technology, and particularly to a control method for a zero-cold-water supply system, the zero-cold-water supply system, and an H-type water valve. The control method for the zero-cold-water supply system includes the following steps: obtaining the operating position of the circulation pump based on the inlet water temperature T_in, ambient temperature T_amb, return pipe length L1, the number of working check valves A1, and the hot water setting input by the user; determining the outlet water temperature T_out and the set temperature T_set corresponding to the hot water setting; if the outlet water temperature T_out ≥ the set temperature T_set, the circulation pump stops, and the preheating stage ends; if the outlet water temperature T_out < the set temperature T_set, the circulation pump continues to operate at the current operating position, or the circulation pump adjusts its operating position and continues to operate. This control method for the zero-cold-water supply system avoids the cross-flow problem caused by the check valve in the H-type water valve getting stuck, ensuring the stability of the zero-cold-water supply.

Description

Technical Field

[0001] This invention relates to the field of gas water heater technology, and in particular to a control method for a zero-cold-water supply system, a zero-cold-water supply system, and an H-type water valve. Background Technology

[0002] With the increasing popularity of gas water heaters with zero cold water, existing technologies for older installations without return water pipes typically use an H-type water valve connected in series with the furthest cold water pipe, as described in patent 202221710844.1, to achieve circulating heating. However, the H-type water valve usually employs a one-way valve structure, which is easily jammed by impurities and scale in the pipes, causing cross-contamination. Currently, the market complaint rate is 1.5%. The main industry solution is to add a filter at the return point of the H-type water valve; however, this device also has a drawback: after prolonged use, impurities in the water can easily clog the filter screen.

[0003] Therefore, there is an urgent need to design a control method for a zero-cold-water supply system, a zero-cold-water supply system, and an H-type water valve to solve the above technical problems. Summary of the Invention

[0004] One objective of this invention is to provide a control method for a zero-cold-water supply system that can avoid cross-flow problems caused by the jamming of the one-way valve in the H-type water valve, thus ensuring the stability of the zero-cold-water supply.

[0005] To achieve this objective, the present invention adopts the following technical solution: A control method for a zero-cold-water supply system is provided, applied to the preheating stage of the zero-cold-water supply system. The zero-cold-water supply system includes an H-type water valve, a hot water pipe, a cold water pipe, a circulating pump, and a heat exchanger. The first end of the cold water pipe is connected to the inlet of the heat exchanger, the first end of the hot water pipe is connected to the outlet of the heat exchanger, and the second end of the hot water pipe and the second end of the cold water pipe are connected through the H-type water valve to form a return water pipeline. The H-type water valve is equipped with at least two one-way valves connected in series. The circulating pump is used to enable the water in the hot water pipe to enter the heat exchanger through the cold water pipe. The controller of the zero cold water supply system is used to obtain the ambient temperature T_amb and inlet temperature T_in at the inlet, the outlet temperature T_out at the outlet, and the number A1 of the one-way valves in operation. The control method for the zero-cold-water supply system includes the following steps: The operating position of the circulation pump is obtained based on the inlet water temperature T_in, the ambient temperature T_amb, the length of the return water pipe L1, the number of working one-way valves A1, and the hot water setting input by the user. Determine the difference between the outlet water temperature T_out and the set temperature T_set corresponding to the hot water setting; If the outlet water temperature T_out ≥ the set temperature T_set, then the circulation pump stops and the preheating stage ends; If the outlet water temperature T_out is less than the set temperature T_set, then the circulation pump continues to operate at the current operating level, or the circulation pump adjusts its operating level and continues to operate.

[0006] Optionally, the controller is used to obtain the return water temperature T_back at the water outlet, determine the return water temperature T_back and the safe temperature T_safe corresponding to the hot water setting, wherein the safe temperature T_safe is less than the set temperature T_set; If the return water temperature T_back ≥ the safe temperature T_safe or the outlet water temperature T_out ≥ the set temperature T_set, then the circulation pump stops and the preheating stage ends. If the return water temperature T_back < the safe temperature T_safe and the outlet water temperature T_out < the set temperature T_set, then the circulation pump continues to operate at the current operating level, or the circulation pump adjusts its operating level and continues to operate.

[0007] Optionally, if the outlet water temperature T_out < the set temperature T_set and the duration is less than the first preset duration t1, then the circulation pump continues to work at the current working speed. If the outlet water temperature T_out is less than the set temperature T_set and the duration is greater than or equal to the first preset duration t1, then the circulating pump continues to work at a higher working speed than the current working speed.

[0008] Another objective of this invention is to provide a zero-cold-water supply system that can avoid the cross-flow problem caused by the jamming of the one-way valve in the H-type water valve, thus ensuring the stability of the zero-cold-water supply.

[0009] To achieve this objective, the present invention adopts the following technical solution: A zero-cold-water supply system is provided, which is controlled by the control method of the zero-cold-water supply system described above. The zero-cold-water supply system further includes a flow sensor, a first temperature sensor, a second temperature sensor, and a third temperature sensor connected to the controller. The flow sensor is used to detect the water flow rate in the return water pipe. The first temperature sensor is used to detect the ambient temperature T_amb at the water inlet. The second temperature sensor is used to detect the inlet water temperature T_in at the water inlet. The third temperature sensor is used to detect the outlet water temperature T_out at the water outlet.

[0010] Another objective of this invention is to provide an H-type water valve that can avoid the cross-flow problem caused by the jamming of the one-way valve in the H-type water valve, thus ensuring the stability of the zero-cold-water supply.

[0011] To achieve this objective, the present invention adopts the following technical solution: An H-type water valve is provided, comprising a first straight pipe, a second straight pipe, a horizontal pipe, and multiple one-way valves. The first straight pipe and the second straight pipe each have two through ends, and the horizontal pipe connects the middle section of the first straight pipe and the middle section of the second straight pipe. The H-type water valve is installed in the zero cold water supply system. One end of the first straight pipe is connected to the hot water pipe of the zero cold water supply system, and the other end of the first straight pipe is connected to the user end. One end of the second straight pipe is connected to the cold water pipe of the zero cold water supply system, and the other end of the second straight pipe is connected to the user end. The one-way valve is installed at one end of the horizontal pipe and / or the first straight pipe.

[0012] Optionally, the H-type water valve includes a hot water tee and a cold water tee. The hot water tee has a first inlet pipe and a first circulation pipe connected together, and the cold water tee has a second inlet pipe and a second circulation pipe connected together. The first inlet pipe is a first straight pipe, and the second inlet pipe is a second straight pipe. A union nut is fitted on one of the outer circumferences of the first circulation pipe and the second circulation pipe, and the other of the two is provided with an external thread structure that mates with the union nut. The first circulation pipe and the second circulation pipe are detachably connected to form the horizontal pipe.

[0013] Optionally, two check valves are provided, and both check valves are located inside the second circulation pipe; or, Two check valves are provided: one check valve is located at the inlet of the first water inlet pipe, and the other check valve is located inside the second circulation pipe.

[0014] Optionally, the side wall of the second water inlet pipe is provided with an installation through hole, and one of the one-way valves is disposed in the second circulation pipe through the installation through hole. The H-type water valve also includes a sealing element, which is sealed at the installation through hole.

[0015] Optionally, a limiting protrusion is provided inside the second circulation tube, and one of the one-way valves is disposed inside the second circulation tube through the mounting through hole and abuts against the limiting protrusion.

[0016] Optionally, the H-type water valve further includes a sleeve, and a plurality of one-way valves are provided inside the horizontal pipe or the first straight pipe, with the sleeve sandwiched between two adjacent one-way valves.

[0017] The beneficial effects of the present invention include at least the following: This invention provides a control method for a zero-cold-water supply system, comprising the following steps: obtaining the operating position of the circulation pump based on the inlet water temperature T_in, the ambient temperature T_amb, the length L1 of the return water pipe, the number of working one-way valves A1, and the hot water setting input by the user. The preheating stage of the zero-cold-water supply system is used to preheat the water temporarily stored in the return water pipe. Through the guiding effect of the one-way valve installed in the H-type water valve, water in the hot water pipe enters the cold water pipe through the H-type water valve, and then flows from the cold water pipe to the inlet of the water heater. The inlet water temperature T_in is the current inlet water temperature T_in detected at the inlet after the user triggers the zero-cold-water command; the ambient temperature T_amb is the current ambient temperature T_amb detected at the inlet; and the outlet water temperature T_out is the temperature of the water heated by the water heater as it flows into the hot water pipe at the outlet. The length L1 of the return water pipe is the sum of the lengths of the hot water pipe, the cold water pipe, and the heat exchanger tube of the water heater. The length of the heat exchanger tube inside the water heater is a fixed value, while the lengths of the hot water pipe and the cold water pipe are determined after the water heater is installed. Therefore, the length L1 of the return water pipe is determined after the water heater is installed and can be input through the water heater's control panel. After obtaining the above parameters, the controller outputs the operating level of the circulation pump according to a preset algorithm. The circulation pump operates according to this operating level to control the water flow Q in the return water pipe. The controller compares the outlet water temperature T_out with the set temperature T_set corresponding to the hot water setting. If the outlet water temperature T_out ≥ the set temperature T_set, the circulation pump stops, and the preheating stage ends. If the outlet water temperature T_out < the set temperature T_set, the circulation pump continues to operate at the current operating level, or the circulation pump adjusts its operating level to continue operating. When the outlet water temperature T_out is greater than or equal to the set temperature T_set, it is considered that the water temporarily stored in the return water pipe has been preheated to the set temperature T_set corresponding to the hot water setting input by the user. The preheating phase of the zero-cold-water supply system ends, and it can enter the normal water supply phase to provide hot water to the user. If the outlet water temperature T_out is less than the set temperature T_set, it means that the water temporarily stored in the return water pipe has not yet been preheated to the set temperature T_set corresponding to the hot water setting input by the user. The water needs to be heated further. During this heating process, the circulation pump can continue operating at its current setting or by adjusting the setting. Adjusting the setting adjusts the water flow rate Q in the return water pipe, thereby changing the water heating rate.

[0018] The control method for a zero-cold-water supply system provided by this invention is applied to the preheating stage of the system. It uses inlet water temperature T_in, ambient temperature T_amb, return pipe length L1, number of operating check valves A1, and user-input hot water setting as input parameters to adjust the operating setting of the circulating pump. The zero-cold-water supply system employs an H-type water valve with multiple check valves. The operating setting of the circulating pump can be adjusted according to the number of normally operating H-type water valves. This allows for the use of multiple check valves to prevent cross-contamination when one check valve is stuck, and also solves the problem of unstable water supply caused by excessively rapid water temperature rise when a check valve is stuck.

[0019] This invention provides a zero-cold-water supply system, controlled by the aforementioned control method. The zero-cold-water supply system further includes a first temperature sensor, a second temperature sensor, and a third temperature sensor connected to the controller. The first temperature sensor detects the ambient temperature T_amb at the water inlet of the water heater, the second temperature sensor detects the inlet water temperature T_in at the water inlet of the water heater, and the third temperature sensor detects the outlet water temperature T_out at the outlet of the water heater. The zero-cold-water supply system also includes a flow sensor connected to the controller. The flow sensor detects the water flow rate in the return water pipe, allowing the controller to determine the number A1 of operating check valves. If a check valve fails, its resistance to water flow decreases. The flow sensor then detects that the operating position of the circulation pump remains unchanged, while the water flow rate in the return water pipe increases. The controller determines the number A1 of operating check valves based on the water flow rate corresponding to the operating position of the circulation pump. This zero-cold-water supply system avoids the cross-flow problem caused by the check valve in the H-type water valve becoming stuck, ensuring the stability of the zero-cold-water supply.

[0020] This invention provides an H-type water valve, comprising a first straight pipe, a second straight pipe, a horizontal pipe, and multiple one-way valves. Both the first and second straight pipes have two through-through ends. The horizontal pipe connects the middle sections of the first and second straight pipes, forming an H-shape. When the H-type water valve is installed in a zero-cold-water supply system, one end of the first straight pipe is connected to the hot water pipe of the system, and the other end of the second straight pipe is connected to the user end. One end of the second straight pipe is connected to the cold water pipe of the system, and the other end of the second straight pipe is also connected to the user end. When the zero-cold-water supply system is in the preheating stage, the user end is closed, and both the other ends of the first and second straight pipes are closed. One-way valves are located at one end of the horizontal pipe and / or the first straight pipe, with their outlets connected to one end of the first straight pipe via a hot water pipe. The first end of the first straight pipe is the inlet of the H-type water valve. The inlet is connected to one end of the second straight pipe via a cold water pipe, and the other end of the second straight pipe is the outlet of the H-type water valve. When the zero-cold-water supply system is in the preheating stage, water in the hot water pipe flows to the first straight pipe, and then through the check valve in the first straight pipe and / or the check valve in the horizontal pipe to the second straight pipe. It then flows back to the heat exchanger via the cold water pipe. Water in the cold water pipe cannot flow backwards; the check valves prevent cross-contamination. Furthermore, with multiple check valves, even if one check valve jams, other check valves can prevent backflow. When the H-type water valve uses only one check valve, impurities and scale in the pipes can jam it, causing cross-contamination; the current customer complaint rate is 1.5%. Therefore, if the H-type water valve uses two check valves, the theoretical customer complaint rate will be 1.5% × 1.5% = 2.25%, reducing the probability of cross-contamination due to check valve jamming. This H-type water valve can avoid the cross-flow problem caused by the one-way valve in the H-type water valve getting stuck, thus ensuring the stability of the zero cold water supply. Attached Figure Description

[0021] Figure 1 This is a flowchart of the control method for the zero-cold-water supply system provided in the embodiments of the present invention; Figure 2 This is a schematic diagram of the control method for the zero-cold-water supply system provided in an embodiment of the present invention; Figure 3 This is a schematic diagram of the structure of the first H-type water valve provided in the embodiment of the present invention; Figure 4 This is a cross-sectional view of the first type H-shaped water valve provided in the embodiment of the present invention; Figure 5 This is a cross-sectional view of the second type H-type water valve provided in the embodiment of the present invention; Figure 6 This is an exploded view of the structure of the second type H-type water valve provided in the embodiment of the present invention; Figure 7This is a structural anatomical view of the second type H-type water valve provided in this embodiment of the invention; Figure 8 This is a schematic diagram of the structure of the third type H-type water valve provided in the embodiment of the present invention; Figure 9 This is a cross-sectional view of the third type H-type water valve provided in the embodiment of the present invention; Figure 10 This is an exploded view of the structure of the third type H-type water valve provided in the embodiment of the present invention; Figure 11 This is a structural anatomical view of the third type H-type water valve provided in this embodiment of the invention.

[0022] Figure Labels 1. H-type water valve; 101. Inlet; 102. Outlet; 11. Hot water tee; 111. First inlet pipe; 1111. First stepped surface; 112. First circulation pipe; 12. Cold water tee; 121. Second inlet pipe; 1211. Mounting through hole; 1212. Limiting hole; 122. Second circulation pipe; 1221. Second stepped surface; 1222. Limiting protrusion; 123. Seal; 1231. Plug; 12311. Sealing ring; 12312. Fixing groove; 1232. Screw; 13. Check valve; 14. Sleeve; 15. Gasket; 16. Union nut; 2. Hot water pipe; 3. Cold water pipe; 4. Circulating pump; 5. Heat exchanger; 501. Inlet; 502. Outlet. Detailed Implementation

[0023] To make the technical problems solved by the present invention, the technical solutions adopted, and the technical effects achieved clearer, the technical solutions of the present invention will be further described below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are merely for explaining the present invention and are not intended to limit the present invention. Furthermore, it should be noted that, for ease of description, only the parts related to the present invention are shown in the accompanying drawings, not all of them.

[0024] In the description of this invention, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0025] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0026] In the description of this embodiment, the terms "upper," "lower," "left," and "right," etc., refer to the orientation or positional relationship shown in the accompanying drawings. They are used only for ease of description and simplification of operation, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention. In addition, the terms "first" and "second" are used only for distinction in description and have no special meaning.

[0027] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0028] like Figure 1 As shown, this embodiment provides a control method for a zero-cold-water supply system, applied to the preheating stage of the zero-cold-water supply system. The zero-cold-water supply system includes an H-type water valve 1, a hot water pipe 2, a cold water pipe 3, a circulating pump 4, and a heat exchanger 5. The first end of the cold water pipe 3 is connected to the inlet 501 of the heat exchanger 5, and the first end of the hot water pipe 2 is connected to the outlet 502 of the heat exchanger 5. The second ends of the hot water pipe 2 and the second ends of the cold water pipe 3 are connected through the H-type water valve 1 to form a return water pipeline. At least two one-way valves 13 connected in series are installed in the H-type water valve 1. The circulating pump 4 is used to allow water in the hot water pipe 2 to enter the heat exchanger 5 through the cold water pipe 3. The controller of the zero-cold-water supply system is used to obtain the ambient temperature T_amb at the inlet 501, the inlet water temperature T_in, the outlet water temperature T_out at the outlet 502, and the number A1 of the one-way valves 13 in operation.

[0029] The control method for a zero-cold-water supply system includes the following steps: The operating setting of the circulation pump 4 is determined based on the inlet water temperature T_in, ambient temperature T_amb, return water pipe length L1, the number of operating check valves 13 A1, and the hot water setting input by the user. (Refer to...) Figure 2The preheating stage of the zero-cold-water supply system is used to preheat the water temporarily stored in the return water pipe. Through the flow guiding effect of the one-way valve 13 installed in the H-type water valve 1, the water in the hot water pipe 2 enters the cold water pipe 3 through the H-type water valve 1, and then flows from the cold water pipe 3 to the inlet 501. Among them, the inlet water temperature T_in is the current inlet water temperature T_in detected at the inlet 501 after the user triggers the zero-cold-water command, the ambient temperature T_amb is the current ambient temperature T_amb detected at the inlet 501, and the outlet water temperature T_out is the temperature of the water after it has been heated by the heat exchanger 5 and flows to the hot water pipe 2 through the outlet 502. The length L1 of the return water pipe is the sum of the lengths of the hot water pipe 2, the cold water pipe 3, and the heat exchange tube inside the water heater. The length of the heat exchange tube inside the water heater is a fixed value, while the lengths of the hot water pipe 2 and the cold water pipe 3 are determined after the water heater is installed. Therefore, the length L1 of the return water pipe is determined after the water heater is installed and can be input through the water heater's control panel. After obtaining the above parameters, the controller outputs the operating level of the circulation pump 4 according to a preset algorithm. The circulation pump 4 operates according to this operating level to control the water flow rate Q in the return water pipe.

[0030] The system compares the outlet water temperature T_out with the set temperature T_set corresponding to the hot water setting. If the outlet water temperature T_out is greater than or equal to the set temperature T_set, the circulation pump 4 stops, and the preheating stage ends. If the outlet water temperature T_out is less than the set temperature T_set, the circulation pump 4 continues to operate at its current setting, or the circulation pump 4 adjusts its operating setting. When the outlet water temperature T_out is greater than or equal to the set temperature T_set, it is considered that the water temporarily stored in the return water pipe has been preheated to the set temperature T_set corresponding to the hot water setting input by the user. The preheating stage of the zero-cold-water supply system ends, and the system can enter the normal water supply stage to provide hot water to the user. If the outlet water temperature T_out < the set temperature T_set, meaning the water temporarily stored in the return water pipe has not yet been preheated to the set temperature T_set corresponding to the hot water setting input by the user, it is necessary to continue heating the water temporarily stored in the return water pipe. During this heating process, the circulation pump 4 can continue to work at the current working setting, or continue to work after adjusting the working setting. Adjusting the working setting can adjust the water flow rate Q in the return water pipe to change the water heating speed.

[0031] The control method for the zero-cold-water supply system provided in this embodiment is applied to the preheating stage of the zero-cold-water supply system. It uses the inlet water temperature T_in, ambient temperature T_amb, return pipe length L1, the number of working check valves 13 A1, and the user-input hot water setting as input parameters to adjust the operating setting of the circulating pump 4. The zero-cold-water supply system uses an H-type water valve 1 with multiple check valves 13. The operating setting of the circulating pump 4 can be adjusted according to the number of normally operating H-type water valves 1. This not only avoids cross-contamination caused by one check valve 13 becoming stuck, but also solves the problem of unstable system water supply caused by excessively rapid water temperature rise when a check valve 13 becomes stuck.

[0032] Optionally, the controller is used to obtain the return water temperature T_back at the outlet 502 of the water heater, and determine whether the return water temperature T_back is equal to the safe temperature T_safe corresponding to the hot water setting. The safe temperature T_safe is less than the set temperature T_set. If the return water temperature T_back is greater than or equal to the safe temperature T_safe, or the outlet water temperature T_out is greater than or equal to the set temperature T_set, then the circulation pump 4 stops, and the preheating stage ends. If the return water temperature T_back is less than the safe temperature T_safe and the return water temperature T_back is less than the set temperature T_set, then the circulation pump 4 continues to work at the current operating setting, or the circulation pump 4 adjusts its operating setting and continues to work. The return water temperature T_back is the temperature of the water after it has been heated by the heat exchanger 5 flows to the hot water pipe 2 and then flows back to the inlet 501 through the cold water pipe 3. Both the return water temperature T_back and the inlet water temperature T_in are the water temperature at the inlet 501, but their detection times are different. The water in the return water pipe enters the heat exchanger 5 through the inlet 501 and will be heated again. If the return water temperature T_back ≥ the safe temperature T_safe, the circulation pump 4 will stop and the preheating stage will end. This is to prevent the water in the return water pipe from being heated again by the heat exchanger 5 before the temperature at the inlet 501 reaches the set temperature, which would cause it to exceed the safe temperature.

[0033] Optionally, if the outlet water temperature T_out < the set temperature T_set and the duration is less than the first preset duration t1, the circulation pump 4 continues to operate at the current operating level; if the outlet water temperature T_out < the set temperature T_set and the duration is greater than or equal to the first preset duration t1, the circulation pump 4 continues to operate at a higher operating level than the current operating level. Increasing the operating level of the circulation pump 4 increases the water flow rate Q in the circulation pipe, thereby accelerating the heating speed of the water so that the outlet water temperature T_out reaches the set temperature T_set as quickly as possible. The first preset duration t1 can be stored in the controller before the water heater leaves the factory. The range of the first preset duration t1 can be determined according to the actual power of the water heater. For example, the first preset duration t1 can be set to 1 minute. If the water in the return pipe has not been heated to the set temperature within 1 minute during the preheating stage, the operating level needs to be increased to improve the heating speed.

[0034] Optionally, the number of check valves 13 installed in the H-type water valve 1 is A1, and the number of working check valves 13 is A2, where A1≥A2≥1. A decrease in the number of working check valves 13 reduces the operating speed of the circulation pump 4. Multiple check valves 13 connected in series are installed in the H-type water valve 1. Each check valve 13 can guide the water within the H-type water valve 1. If a check valve 13 fails during use, the resistance of the H-type water valve 1 to water decreases. Therefore, depending on the number of check valves 13, the operating speed of the circulation pump 4 output by the controller also varies. This achieves dynamic adjustment of the operating speed of the circulation pump 4 based on the number of working check valves 13 in the H-type water valve 1, thus avoiding the impact of the number of working check valves 13 on the zero-cold-water supply.

[0035] like Figure 2As shown, this embodiment provides a zero-cold-water supply system, controlled by the aforementioned control method. The zero-cold-water supply system includes an H-type water valve 1, a hot water pipe 2, a cold water pipe 3, a circulating pump 4, and a heat exchanger 5. The first end of the cold water pipe 3 is connected to the inlet 501 of the heat exchanger 5, and the first end of the hot water pipe 2 is connected to the outlet 502 of the heat exchanger 5. The second ends of the hot water pipe 2 and the second ends of the cold water pipe 3 are connected through the H-type water valve 1 to form a return water pipeline. The zero-cold-water supply system also includes a first temperature sensor, a second temperature sensor, and a third temperature sensor connected to the controller. The first and second temperature sensors are located at the inlet 501. The first temperature sensor detects the ambient temperature T_amb at the inlet 501, the second temperature sensor detects the inlet water temperature T_in at the inlet 501, and the third temperature sensor detects the outlet water temperature T_out at the outlet 502. The zero-cold-water supply system also includes a flow sensor connected to the controller, which detects the water flow rate in the return water pipeline. Because the H-type water valve 1 of the zero-cold-water supply system provided in this embodiment is equipped with at least two one-way valves 13 connected in series, the more one-way valves 13 that are working, the greater the resistance to water flow in the return water pipe. Therefore, the controller can obtain the number A1 of working one-way valves 13 based on the water flow rate in the return water pipe. If a one-way valve 13 fails, the resistance of the one-way valve 13 to water flow decreases, and the flow sensor can detect that the operating position of the circulation pump 4 has not changed, while the water flow rate in the return water pipe increases. The controller determines the number A1 of working one-way valves 13 based on the water flow rate corresponding to the operating position of the circulation pump 4.

[0036] like Figure 3 and Figure 4As shown, this embodiment also provides an H-type water valve 1, including a first straight pipe, a second straight pipe, a horizontal pipe, and multiple one-way valves 13. Both the first and second straight pipes have two through-holes. The horizontal pipe connects the middle sections of the first and second straight pipes, forming an H-shape. When the H-type water valve 1 is installed in a zero-cold-water supply system, one end of the first straight pipe is connected to the hot water pipe 2, and the other end of the second straight pipe is connected to the user end. One end of the second straight pipe is connected to the cold water pipe 3, and the other end of the second straight pipe is also connected to the user end. When the zero-cold-water supply system is in the preheating stage, the user end is in a closed state, so both the other ends of the first and second straight pipes are closed. The one-way valve 13 is located at one end of the horizontal pipe and / or the first straight pipe. The outlet 502 is connected to one end of the first straight pipe via the hot water pipe 2. The one end of the first straight pipe is the inlet 101 of the H-type water valve 1. The inlet 501 is connected to one end of the second straight pipe via the cold water pipe 3. The end of the second straight pipe is the outlet 102 of the H-type water valve 1. When the zero-cold-water supply system is in the preheating stage, the water in the hot water pipe 2 flows to the first straight pipe, and then through the one-way valve 13 in the first straight pipe and / or the one-way valve 13 in the horizontal pipe to the second straight pipe. It then flows back to the heat exchanger 5 via the cold water pipe 3. The water in the cold water pipe 3 cannot flow backwards; the one-way valve 13 prevents cross-contamination. Furthermore, with multiple one-way valves 13, even if one one-way valve 13 is stuck, other one-way valves 13 can still prevent backflow. When the H-type water valve 1 uses only one one-way valve 13, impurities and scale in the pipes can cause the one-way valve 13 to become stuck, resulting in cross-contamination. Currently, the customer complaint rate in the market is 1.5%. In this embodiment, the H-type water valve 1 uses two one-way valves 13. Theoretically, the customer complaint rate will be 1.5% × 1.5% = 2.25%, which can reduce the probability of cross-flow caused by the one-way valve 13 getting stuck.

[0037] Optionally, such as Figure 3 and Figure 4As shown, the H-type water valve 1 includes a hot water tee 11 and a cold water tee 12. The hot water tee 11 has a first inlet pipe 111 and a first circulation pipe 112 connected together. The cold water tee 12 has a second inlet pipe 121 and a second circulation pipe 122 connected together. The first inlet pipe 111 is a first straight pipe, and the second inlet pipe 121 is a second straight pipe. A union nut 16 is fitted onto the outer periphery of the first circulation pipe 112 and the outer periphery of the second circulation pipe 122, and the other has an external thread structure that mates with the union nut 16. The outer peripheries of the first circulation pipe 112 and the second circulation pipe 122 are detachably connected to form a horizontal pipe. In this embodiment, a union nut 16 is provided on the outer periphery of the first circulation pipe 112, and an external thread structure is provided on the outer periphery of the second circulation pipe 122. The cold water tee 12 and the hot water tee 11 are connected by the union nut 16 threadedly connected to the outer periphery of the second circulation pipe 122. Preferably, the H-type water valve 1 further includes a gasket 15, which is disposed in the inner cavity of the union nut 16. The second circulation pipe 122 is inserted into the inner cavity of the union nut 16, and after the two are connected, the gasket 15 is pressed against the bottom wall of the inner cavity of the union nut 16 to seal the gap at the connection between the cold water tee 12 and the hot water tee 11 and ensure the sealing performance.

[0038] In one embodiment, such as Figure 4 As shown, two check valves 13 are provided. One check valve 13 is located at the inlet of the first water inlet pipe 111, and the other check valve 13 is located inside the second circulation pipe 122. By arranging the check valves 13 in sections, the length requirement of the second circulation pipe 122 can be reduced. Furthermore, since the check valve 13 is installed inside the first water inlet pipe 111, and the installation and pushing direction of the check valve 13 is consistent with the water flow direction, the external force exerted on the check valve 13 by the water flow will not affect the sealing stability between the check valve 13 and the inner wall of the first water inlet pipe 111.

[0039] Optionally, such as Figure 4 As shown, the inner wall of the first inlet pipe 111 is provided with a first stepped surface 1111. The one-way valve 13 is inserted into the first inlet pipe 111 and abuts against the first stepped surface 1111. The first stepped surface 1111 is used to limit the installation position of the one-way valve 13 in the first inlet pipe 111. A sealing ring is provided on the outer periphery of the one-way valve 13 to make an interference fit with the inner wall surface of the first inlet pipe 111, thereby preventing the one-way valve 13 from detaching from the hot water tee 11. Alternatively, a sealing ring can be provided, and after the one-way valve 13 is inserted into the first inlet pipe 111, the sealing ring is then inserted into the first inlet pipe 111, with the sealing ring making an interference fit with the inner wall surface of the first inlet pipe 111, thereby preventing the one-way valve 13 from detaching from the hot water tee 11.

[0040] Optionally, such as Figure 4As shown, the inner wall of the second circulation pipe 122 is provided with a second stepped surface 1221. The one-way valve 13 is inserted into the second circulation pipe 122 and abuts against the second stepped surface 1221. The second stepped surface 1221 is used to limit the installation position of the one-way valve 13 in the circulation channel of the cold water tee 12.

[0041] In one embodiment, such as Figures 5 to 7 As shown, two check valves 13 are provided, both of which are located within the second circulation pipe 122. A sealing ring is provided on the outer periphery of each check valve 13. When the check valve 13 is inserted into the second circulation pipe 122, the sealing ring deforms to ensure an interference fit between the check valve 13 and the inner wall of the second circulation pipe 122. The check valve 13 is positioned within the second circulation pipe 122 with its installation direction aligned with the water flow direction. The external force exerted on the check valve 13 by the water flow will not affect the sealing stability between the check valve 13 and the inner wall of the second circulation pipe 122.

[0042] Optionally, such as Figure 5 As shown, the H-type water valve 1 also includes a sleeve 14, which is located inside the second circulation pipe 122. The sleeve 14 is sandwiched between two check valves 13 and is used to ensure that there is a predetermined interval between the two check valves 13 to avoid interference between them. In a specific implementation, one check valve 13, the sleeve 14, and the other check valve 13 are sequentially installed into the second circulation pipe 122, with the first installed check valve 13 abutting against the second stepped surface 1221.

[0043] In other embodiments, two check valves 13 are provided, both of which are located inside the first water inlet pipe 111. Alternatively, a sleeve 14 can be located inside the first water inlet pipe 111, sandwiched between the two check valves 13. In specific implementation, one check valve 13, the sleeve 14, and the other check valve 13 are sequentially installed into the first water inlet pipe 111, with the first installed check valve 13 abutting against the first stepped surface 1111.

[0044] In one embodiment, such as Figure 8 As shown, the side wall of the second inlet pipe 121 is provided with a mounting through hole 1211. A one-way valve 13 is installed in the second circulation pipe 122 through the mounting through hole 1211. The H-type water valve 1 also includes a sealing element 123, which is sealed at the mounting through hole 1211. That is, the cold water tee 12 includes a tee body and a sealing element 123. When the sealing element 123 is not sealed at the mounting through hole 1211, the one-way valve 13 can be installed through the mounting through hole 1211. By adding this assembly method, one one-way valve 13 can be installed from both ends of the second circulation pipe 122. Of course, it is also possible to install only one one-way valve 13 in the second circulation pipe 122 through the mounting through hole 1211.

[0045] Optionally, the seal 123 includes a plug 1231 and a screw 1232. The plug 1231 is inserted into the mounting through hole 1211. A sealing ring 12311 is provided on the outer periphery of the plug 1231. The sealing ring 12311 is interference-fitted with the inner wall of the mounting through hole 1211, thereby ensuring the sealing effect of the plug 1231 on the mounting through hole 1211. A fixing groove 12312 is also provided on the outer periphery of the plug 1231, and a limiting hole 1212 is also provided on the side wall of the second water inlet pipe 121. The screw 1232 passes through the limiting hole 1212 and extends into the fixing groove 12312. The screw 1232 restricts the axial movement of the plug 1231, preventing the plug 1231 from detaching from the mounting through hole 1211. In this embodiment, the fixing groove 12312 is an annular groove so that after the plug 1231 is inserted into the mounting through hole 1211, the axial position of the plug 1231 is determined, and the screw 1232 can be inserted into the fixing groove 12312.

[0046] Optionally, a limiting protrusion 1222 is provided inside the second circulation pipe 122, and a one-way valve 13 is disposed inside the second circulation pipe 122 through a mounting through hole 1211 and abuts against the limiting protrusion 1222. The limiting protrusion 1222 is used to limit the position of the one-way valve 13 inserted into the second circulation pipe 122. In this embodiment, the limiting protrusion 1222 is an annular protrusion disposed on the inner wall of the second circulation pipe 122 to ensure that the one-way valve 13 is subjected to uniform force at all points.

[0047] In one embodiment, such as Figures 9 to 11 As shown, two check valves 13 are provided, and both check valves 13 are located within the second circulation pipe 122. One check valve 13 can be inserted through the port of the second circulation pipe 122, while the other check valve 13 is inserted through the mounting through hole 1211. When a limiting protrusion 1222 is provided within the second circulation pipe 122, the limiting protrusion 1222 is sandwiched between the two check valves 13 to limit the distance between them.

[0048] In other embodiments, two check valves 13 are provided, and both check valves 13 are located inside the second circulation pipe 122. When the side wall of the second water inlet pipe 121 is provided with an installation through hole 1211, the limiting protrusion 1222 may not be provided in the second circulation pipe 122, but a sleeve 14 may still be provided. The sleeve 14 can be inserted from the port of the second circulation pipe 122 or the installation through hole 1211.

[0049] like Figures 8 to 11 As shown, in other embodiments, a sealing cap may also be provided at the other end of the hot water tee 11 to accommodate a zero-cold-water supply system with a return water pipeline.

[0050] The above embodiments merely illustrate the basic principles and characteristics of the present invention. The present invention is not limited to the above embodiments. Various changes and modifications can be made to the present invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A control method for a zero-cold-water supply system, characterized in that, The system is used in the preheating stage of a zero-cold-water supply system. The zero-cold-water supply system includes an H-type water valve (1), a hot water pipe (2), a cold water pipe (3), a circulating pump (4), and a heat exchanger (5). The first end of the cold water pipe (3) is connected to the inlet (501) of the heat exchanger (5), and the first end of the hot water pipe (2) is connected to the outlet (502) of the heat exchanger (5). The second end of the hot water pipe (2) and the second end of the cold water pipe (3) are connected through the H-type water valve (1) to form a return water pipeline. The H-type water valve (1) is equipped with at least two one-way valves (13) connected in series. The circulating pump (4) is used to enable the water in the hot water pipe (2) to enter the heat exchanger (5) through the cold water pipe (3). The controller of the zero cold water supply system is used to obtain the ambient temperature T_amb and inlet water temperature T_in at the inlet (501), the outlet water temperature T_out at the outlet (502), and the number A1 of the one-way valves (13) in operation. The control method for the zero-cold-water supply system includes the following steps: The operating position of the circulation pump (4) is obtained based on the inlet water temperature T_in, the ambient temperature T_amb, the length of the return water pipe L1, the number of working one-way valves (13) A1, and the hot water setting input by the user. Determine the difference between the outlet water temperature T_out and the set temperature T_set corresponding to the hot water setting; If the outlet water temperature T_out ≥ the set temperature T_set, then the circulating pump (4) stops and the preheating stage ends; If the outlet water temperature T_out < the set temperature T_set, then the circulating pump (4) continues to work at the current working level, or the circulating pump (4) adjusts the working level and continues to work.

2. The control method for a zero-cold-water supply system according to claim 1, characterized in that, The controller is used to obtain the return water temperature T_back at the water outlet (502), and determine the return water temperature T_back and the safe temperature T_safe corresponding to the hot water setting, wherein the safe temperature T_safe is less than the set temperature T_set; If the return water temperature T_back ≥ the safe temperature T_safe or the outlet water temperature T_out ≥ the set temperature T_set, then the circulation pump (4) stops and the preheating stage ends; If the return water temperature T_back < the safe temperature T_safe and the outlet water temperature T_out < the set temperature T_set, then the circulation pump (4) continues to work at the current working level, or the circulation pump (4) adjusts the working level and continues to work.

3. The control method for a zero-cold-water supply system according to claim 1, characterized in that, If the outlet water temperature T_out < the set temperature T_set and the duration is less than the first preset duration t1, then the circulating pump (4) continues to work at the current working speed. If the outlet water temperature T_out is less than the set temperature T_set and the duration is greater than or equal to the first preset duration t1, then the circulating pump (4) continues to work at a higher working level than the current working level.

4. A zero-cold-water supply system, characterized in that, The system is controlled by the control method of the zero-cold-water supply system as described in any one of claims 1 to 3. The zero-cold-water supply system further includes a flow sensor, a first temperature sensor, a second temperature sensor, and a third temperature sensor connected to the controller. The flow sensor is used to detect the water flow rate in the return water pipe. The first temperature sensor is used to detect the ambient temperature T_amb at the inlet (501). The second temperature sensor is used to detect the inlet water temperature T_in at the inlet (501). The third temperature sensor is used to detect the outlet water temperature T_out at the outlet (502).

5. An H-type water valve, characterized in that, The H-type water valve (1) includes a first straight pipe, a second straight pipe, a horizontal pipe, and multiple one-way valves (13). The first straight pipe and the second straight pipe both have two through ends, and the horizontal pipe connects the middle section of the first straight pipe and the middle section of the second straight pipe. The H-type water valve (1) is installed in the zero cold water supply system. One end of the first straight pipe is connected to the hot water pipe (2) of the zero cold water supply system, and the other end of the first straight pipe is connected to the user end. One end of the second straight pipe is connected to the cold water pipe (3) of the zero cold water supply system, and the other end of the second straight pipe is connected to the user end. The one-way valve (13) is installed at one end of the horizontal pipe and / or the first straight pipe.

6. The H-type water valve according to claim 5, characterized in that, The H-type water valve (1) includes a hot water tee (11) and a cold water tee (12). The hot water tee (11) has a first inlet pipe (111) and a first circulation pipe (112) connected together. The cold water tee (12) has a second inlet pipe (121) and a second circulation pipe (122) connected together. The first inlet pipe (111) is the first straight pipe, and the second inlet pipe (121) is the second straight pipe. A union nut (16) is fitted on one of the outer periphery of the first circulation pipe (112) and the outer periphery of the second circulation pipe (122), and the other of the two is provided with an external thread structure that cooperates with the union nut (16). The first circulation pipe (112) and the second circulation pipe (122) are detachably connected to form the horizontal pipe.

7. The H-type water valve according to claim 6, characterized in that, Two check valves (13) are provided, and both check valves (13) are located inside the second circulation pipe (122); or, Two one-way valves (13) are provided. One one-way valve (13) is located at the inlet of the first water inlet pipe (111), and the other one-way valve (13) is located in the second circulation pipe (122).

8. The H-type water valve according to claim 7, characterized in that, The second water inlet pipe (121) has an installation through hole (1211) on its side wall. One of the one-way valves (13) is installed in the second circulation pipe (122) through the installation through hole (1211). The H-type water valve (1) also includes a sealing element (123), which is sealed at the installation through hole (1211).

9. The H-type water valve according to claim 8, characterized in that, A limiting protrusion (1222) is provided inside the second circulation pipe (122), and a one-way valve (13) is provided inside the second circulation pipe (122) through the mounting through hole (1211) and abuts against the limiting protrusion (1222).

10. The H-type water valve according to claim 6, characterized in that, The H-type water valve (1) also includes a sleeve (14), and multiple one-way valves (13) are provided in the horizontal pipe or the first straight pipe. The sleeve (14) is sandwiched between two adjacent one-way valves (13).

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