CN111426055A - Water heater and control method thereof - Google Patents

Abstract

The invention relates to a water heater and a control method thereof. The water heater comprises a burner, a heat exchanger, a water inlet pipe and a water outlet pipe. The water inlet pipe and the water outlet pipe are respectively connected with the inlet end and the outlet end of the heat exchanger. The flue gas for water heat exchange in the heat exchanger; the water heater also includes a bypass pipe and a proportional valve, the two ends of the bypass pipe are respectively connected with the water inlet pipe and the water outlet pipe, and the proportional valve is assembled on the bypass pipe; When the water point has an input signal, the water inlet pipe is connected to the water source, and the proportional valve can controllably adjust the proportion of cold water flowing from the water inlet pipe to the water outlet pipe, so as to keep the water temperature from the water outlet pipe constant. When the user uses water, the proportional valve will controllably adjust the proportion of cold water flowing from the water inlet pipe to the water outlet pipe, so that the cold water and hot water are neutralized to adjust the temperature of the water outlet from the water outlet pipe, so that the temperature flowing out from the water outlet pipe remains constant and reduces The hot and cold phenomenon that occurs when water is used.

Description

Water heater and control method thereof

technical field

The invention relates to the technical field of heat exchange equipment, in particular to a water heater and a control method thereof.

Background technique

With economic development and social progress, water heaters appear in people's daily life. Water heater refers to a device that increases the temperature of cold water into hot water through various physical principles within a certain period of time. According to different principles, it can be divided into electric water heaters, gas water heaters, solar water heaters, magnetic water heaters, air energy water heaters and heating water heater etc. Among them, gas water heaters are widely used in people's daily life.

Gas water heater, also known as gas water heater, refers to a gas appliance that uses gas as fuel and transfers heat to the cold water flowing through the heat exchanger through fuel heating to achieve the purpose of preparing hot water.

However, because the water pressure used at home has been changing dynamically, that is, when the combustion power remains unchanged, the water inlet water pressure of the gas water heater has been changing dynamically, so that the water temperature changes when the user uses the gas water heater, and the outlet water temperature appears. The phenomenon of hot and cold.

SUMMARY OF THE INVENTION

Based on this, it is necessary to provide a water heater and a control method for keeping the outlet water temperature constant in view of the problem that the water temperature fluctuates when the traditional gas water heater is used.

A water heater, the water heater includes a burner, a heat exchanger, a water inlet pipe and a water outlet pipe, the water inlet pipe and the water outlet pipe are respectively connected with the inlet end and the outlet end of the heat exchanger, and the burner is used for Combustion produces flue gas that exchanges heat with water in the heat exchanger;

The water heater further comprises a bypass pipe and a proportional valve, two ends of the bypass pipe are respectively connected with the water inlet pipe and the water outlet pipe, and the proportional valve is assembled on the bypass pipe;

Wherein, when it is detected that the water point has an input signal, the water inlet pipe is communicated with the water source, and the proportional valve can controllably adjust the proportion of cold water flowing from the water inlet pipe to the water outlet pipe, so that the water outlet pipe is The outlet water temperature remains constant.

In one embodiment, the water heater further includes a water storage tank, the water storage tank communicates with the water outlet pipe, and the water outlet pipe communicates with the bypass pipe through the water storage tank;

When it is detected that the water point has no input signal and the temperature of the water in the water storage tank is lower than a first preset threshold, the water inlet pipe is disconnected from the water source and the burner works to exchange heat with the heat exchanger.

In one embodiment, the water heater further includes a first communication pipe and a one-way valve, two ends of the first communication pipe are respectively connected with the water inlet pipe and the water outlet pipe, and the one-way valve is assembled on the The first communication pipe is used to restrict the flow of water from the end of the first communication pipe that communicates with the water inlet pipe to the end that communicates with the water outlet pipe; the connection between the first communication pipe and the water outlet pipe be located on the side of the water storage tank away from the heat exchanger;

Wherein, when it is detected that the water point has no input signal and the temperature of the water in the water storage tank is lower than the first preset threshold, the proportional valve can controllably adjust the resistance of the water in the bypass pipe to make the water in the Circulation flows between the water storage tank, the bypass pipe and the heat exchanger.

In one embodiment, when it is detected that the water point has no input signal and the temperature of the water in the water storage tank is greater than or equal to the first preset threshold, the proportional valve controllably adjusts the water in the bypass resistance in the pipe to circulate water among the water storage tank, the first communication pipe and the bypass pipe.

In one embodiment, the communication point between the first communication pipe and the water inlet pipe is located on a side away from the heat exchanger at the communication point between the bypass pipe and the water inlet pipe.

In one embodiment, the water outlet pipe has a water outlet end, and the first communication pipe communicates with the water outlet end of the water outlet pipe.

In one embodiment, the water heater further includes a first temperature sensor, and the first temperature sensor is used to detect the temperature of the water in the water outlet pipe. When it is detected that the water point has an input signal, the proportional valve is adjusted according to the The difference between the temperature of the water in the water outlet pipe and the preset temperature can controllably adjust the proportion of cold water flowing to the water outlet pipe.

In one embodiment, the water outlet pipe has a water outlet end, and the heat exchanger further includes a second communication pipe, and two ends of the second communication pipe are respectively communicated with the water outlet end of the water outlet pipe and the water inlet pipe .

In one embodiment, the water heater further includes a water pump, and the water pump is assembled on the water inlet pipe or the water outlet pipe.

In one embodiment, the water heater further includes a controller, and the burner and the proportional valve are both electrically connected to the controller.

A water heater control method, comprising:

When it is detected that the water point has an input signal, the burner is controlled to work and the water inlet pipe is connected to the water source;

The proportional valve is controlled to adjust the proportion of cold water flowing from the water inlet pipe to the water outlet pipe, so that the temperature of the water outlet from the water outlet pipe is kept constant.

In one embodiment,

When it is detected that the water point has no input signal and the temperature of the water in the water storage tank is greater than or equal to a first preset threshold, controlling the burner to stop working and the water inlet pipe to be disconnected from the water source;

Control water flows between the water storage tank, the bypass pipe and the first communication pipe.

In one embodiment,

When it is detected that the water point has no input signal and the temperature of the water in the water storage tank is lower than the first preset threshold, controlling the burner to work and the water inlet pipe to be disconnected from the water source;

Control the flow of water between the storage tank, bypass pipe and heat exchanger.

In one embodiment,

When it is detected that the water point has no input signal and the water level in the water storage tank is lower than the second preset threshold, the water inlet pipe is controlled to communicate with the water source.

In one embodiment, when it is detected that the water point does not have an input signal for a period greater than a third preset threshold, the water heater is controlled to stand by.

The above water heater and its control method, when the user uses water, the proportional valve will controllably adjust the proportion of cold water flowing from the water inlet pipe to the water outlet pipe, so that the cold water and hot water are neutralized to adjust the temperature of the water outlet from the water outlet pipe, so that the water outlet pipe The temperature of the outflow remains constant, which reduces the phenomenon of hot and cold when the water is used.

Description of drawings

FIG. 1 is a schematic diagram of a water heater provided by an embodiment of the present invention;

FIG. 2 is a flowchart of a water heater control method according to another embodiment of the present invention.

100, water heater; 10, burner; 11, body; 12, ignition needle; 13, ignition needle; 20, heat exchanger; 30, water inlet pipe; 40, water outlet pipe; 41, water outlet; 50, fan; 60, Bypass pipe; 70, proportional valve; 80, connecting pipe; 90, on-off valve; 110, water pump; 120, main pipe; 130, branch pipe; 140, gas valve; 150, segment valve; 160, water storage tank; 170, The first communication pipe; 180, the one-way valve; 190, the second communication pipe.

Detailed ways

In order to make the above objects, features and advantages of the present invention more clearly understood, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without departing from the connotation of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed below.

In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", " Back, Left, Right, Vertical, Horizontal, Top, Bottom, Inner, Outer, Clockwise, Counterclockwise, Axial , "radial", "circumferential" and other indicated orientations or positional relationships are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying the indicated device or Elements must have a particular orientation, be constructed and operate in a particular orientation and are therefore not to be construed as limitations of the invention.

In addition, the terms "first" and "second" are only used for descriptive purposes, and should not be construed as indicating or implying relative importance or implying the number of indicated technical features. Thus, a feature delimited with "first", "second" may expressly or implicitly include at least one of that feature. In the description of the present invention, "plurality" means at least two, such as two, three, etc., unless otherwise expressly and specifically defined.

In the present invention, unless otherwise expressly specified and limited, the terms "installed", "connected", "connected", "fixed" and other terms should be understood in a broad sense, for example, it may be a fixed connection or a detachable connection , or integrated; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between the two elements, unless otherwise specified limit. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

In the present invention, unless otherwise expressly specified and limited, a first feature "on" or "under" a second feature may be in direct contact between the first and second features, or the first and second features indirectly through an intermediary touch. Also, the first feature being "above", "over" and "above" the second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is level higher than the second feature. The first feature being "below", "below" and "below" the second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature has a lower level than the second feature.

It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or an intervening element may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. The terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used herein are for the purpose of illustration only and do not represent the only embodiment.

Referring to FIG. 1 , an embodiment of the present invention provides a water heater 100 , which includes a burner 10 , a heat exchanger 20 , a water inlet pipe 30 and a water outlet pipe 40 , the heat exchanger 20 has an inlet end and an outlet end that communicate with each other, and the water inlet pipe 30 In communication with the inlet end of the heat exchanger 20 , the water outlet pipe 40 is in communication with the outlet end of the heat exchanger 20 , and the burner 10 is used for combustion to generate flue gas for heat exchange with the water flowing in the heat exchanger 20 . When the water point has an input signal, the water inlet pipe 30 is connected to the water source at this time, and the cold water in the water source flows to the water inlet pipe 30, and enters the heat exchanger 20 from the water inlet pipe 30 through the inlet end of the heat exchanger 20. The flue gas exchanges heat with the cold water in the heat exchanger 20, and the hot water formed after the heat exchange flows from the water outlet pipe 40 to the water point for use.

The water heater 100 further includes a fan 50, and the fan 50 rotates to discharge the flue gas after heat exchange with the heat exchanger 20 to the outside.

The water heater 100 further includes a bypass pipe 60 and a proportional valve 70 , two ends of the bypass pipe 60 are respectively connected with the water inlet pipe 30 and the water outlet pipe 40 , and the proportional valve 70 is assembled on the bypass pipe 60 . When the water point has an input signal, the water inlet pipe 30 communicates with the water source, and the proportional valve 70 controllably adjusts the proportion of cold water flowing from the water inlet pipe 30 to the water outlet pipe 40 to keep the outlet water temperature from the water outlet pipe 40 constant.

In the water heater 100 provided by the embodiment of the present invention, both ends of the bypass pipe 60 are respectively connected with the water inlet pipe 30 and the water outlet pipe 40 , and the bypass pipe 60 is equipped with a proportional valve 70 . When the user uses water (when the water point has an input signal), the proportional valve 70 will controllably adjust the proportion of cold water flowing from the water inlet pipe 30 to the water outlet pipe 40, so as to neutralize the cold water and the hot water to adjust the temperature of the water outlet from the water outlet pipe 40, In order to keep the temperature flowing out from the water outlet pipe 40 constant, the phenomenon of sudden cold and sudden heat that occurs when water is used is reduced.

The water heater 100 further includes a controller, the burner 10 and the proportional valve 70 are both electrically connected to the controller, and the controller controls the operation of the burner 10 and the proportional valve 70 .

Further, the water heater 100 further includes a connecting pipe 80 and an on-off valve 90, the connecting pipe 80 is connected with the water inlet pipe 30, and the on-off valve 90 is assembled on the connecting pipe 80 to control the connection between the water inlet pipe 30 and the water source. Specifically, the on-off valve 90 is an electric on-off valve 90, the on-off valve 90 is electrically connected with the controller, and the controller controls the on-off valve 90 to open and close to control the on-off between the water inlet pipe 30 and the water source.

The water heater 100 further includes a water pump 110 . The water pump 110 is assembled on the water inlet pipe 30 or the water outlet pipe 40 to provide pressure for water to flow in the pipes and the heat exchanger 20 . In a specific embodiment, the water pump 110 is assembled on the water inlet pipe 30 . It should be understood that, in other embodiments, the water pump 110 may also be assembled on the water outlet pipe 40, which is not limited herein.

Specifically, the water heater 100 further includes a main pipe 120 , a plurality of branch pipes 130 , a gas valve 140 and a segment valve 150 . One end of the main pipe 120 is communicated with the gas source, the gas valve 140 is assembled on the main pipe 120, the segment valve 150 is communicated with the other end of the main pipe 120, one end of each branch pipe 130 is communicated with the segment valve 150, and the The other end communicates with the burner 10 . When the water point has an input signal, both the gas valve 140 and the segment valve 150 are opened, and the gas enters the corresponding combustion section of the burner 10 from each branch pipe 130 for combustion to generate high-temperature flue gas.

The burner 10 includes a main body 11, an ignition needle 12 and a fire detection needle 13. The ignition needle 12 and the fire detection needle 13 are all connected to the main body 11. The ignition needle 12 discharges, and the gas is ignited and starts to burn to generate a flame. The fire detection needle 13 detects the flame. After the signal, the ignition needle 12 stops discharging. Specifically, the main body 11 is divided into multiple combustion sections, and the ignition needle 12 and the ignition needle 13 are both assembled in the relatively central combustion section. It can be understood that, in other embodiments, the assembly positions of the ignition needle 12 and the ignition needle 13 are also not limited.

The inventor's research found that it generally takes ten seconds or even longer for the water heater 100 to heat the cold water to a temperature that is convenient for use. Only after the cold water is released can the hot water flow out, and it takes a longer time to wait, which not only reduces the user experience, but also causes a waste of resources.

In order to solve the above problem, the water heater 100 is arranged to further include a water storage tank 160 , the water storage tank 160 communicates with the water outlet pipe 40 , and the water outlet pipe 40 communicates with the bypass pipe 60 through the water storage tank 160 .

When the water point has an input signal, the controller controls the on-off valve 90 to open, and the water inlet pipe 30 is connected to the water source. Under the action of the water pump 110, the cold water in the water source flows to the water inlet pipe 30 and passes through the inlet of the heat exchanger 20 through the water inlet pipe 30. The end enters the heat exchanger 20, the flue gas and flow generated by the burner 10 exchange heat with the cold water in the heat exchanger 20, and the hot water formed after the heat exchange flows to the water storage tank 160, and then flows from the water outlet end 41 of the water outlet pipe 40 to the Water point for use. And because the water outlet pipe 40 communicates with the bypass pipe 60 through the water storage tank 160, the cold water in the water inlet pipe 30 enters the water storage tank 160 and mixes with hot water, and then is discharged from the water storage tank 160. The water storage tank 160 can make the cold water and hot water mix more uniformly.

When the water point has no input signal and the temperature of the water in the water storage tank 160 is lower than the first preset threshold, the water inlet pipe 30 is disconnected from the water source, and the burner 10 works to exchange heat with the heat exchanger 20 . That is, when the user does not use water, the water storage tank 160 will store hot water for the user to use next time, which reduces the waiting time for the user to use the hot water next time, improves the user experience, and reduces the waste of resources.

Further, the water heater 100 further includes a first communication pipe 170 and a one-way valve 180. Two ends of the first communication pipe 170 are respectively connected with the water inlet pipe 30 and the water outlet pipe 40. The one-way valve 180 is assembled on the first communication pipe 170 for Water is restricted from flowing from the end of the first communication pipe 170 that communicates with the water inlet pipe 30 to the end that communicates with the water outlet pipe 40 . Wherein, the connection between the first communication pipe 170 and the water outlet pipe 40 is located on the side of the water storage tank 160 away from the heat exchanger 20 .

When it is detected that the water point has an input signal, the water inlet pipe 30 is connected to the water source, the cold water in the water source flows to the water inlet pipe 30, and enters the heat exchanger 20 through the inlet end of the heat exchanger 20 through the water inlet pipe 30. The flue gas exchanges heat with the cold water in the heat exchanger 20, and the hot water formed after the heat exchange flows into the water storage tank 160, and then flows from the water outlet 41 of the water outlet pipe 40 to the water point for use. Due to the restriction of the one-way valve 180 , the hot water flowing out of the water outlet pipe 40 will not return to the water inlet pipe 30 .

When it is detected that the water point has no input signal and the temperature of the water in the water storage tank 160 is lower than the first preset threshold, the proportional valve 70 adjusts the resistance of the water in the bypass pipe 60 to make the water in the water storage tank 160 and the bypass pipe 60 and the heat exchanger 20 circulate and flow. At this time, the flue gas generated by the combustion of the burner 10 can exchange heat with the water flowing in the heat exchanger 20 to ensure that the water in the water storage tank 160 is at a suitable temperature.

Further, when it is detected that the water point has no input signal and the temperature of the water in the water storage tank 160 is greater than or equal to the first preset threshold, the proportional valve 70 adjusts the resistance of the water in the bypass pipe 60 to make the water in the water storage tank 160, There is circulating flow between the first communication pipe 170 and the bypass pipe 60. Under the condition that the water storage tank 160 has a suitable temperature, the water no longer flows through the heat exchanger 20, so as to reduce the resistance encountered by the water flow and reduce the heat loss. Heat dissipation, save energy.

Specifically, the water heater 100 further includes a second temperature sensor, and the second temperature sensor is used to detect the temperature in the water storage tank 160 .

In one embodiment, the connection between the first communication pipe 170 and the water inlet pipe 30 is located on the side away from the heat exchanger 20 at the connection between the bypass pipe 60 and the water inlet pipe 30. At this time, when the water point has no input signal and When the temperature of the water in the water storage tank 160 is greater than or equal to the first preset threshold, the proportional valve 70 adjusts the resistance of the water in the bypass pipe 60 , so that the water flows through the water storage tank 160 and the first communication pipe 170 under the action of the water pump 110 . It circulates with the bypass pipe 60 . It can be understood that, in other embodiments, the connection between the first communication pipe 170 and the water inlet pipe 30 can also be set to be located on the side of the connection between the bypass pipe 60 and the water inlet pipe 30 close to the heat exchanger 20 . limited.

Further, the water outlet pipe 40 has a water outlet end 41, and the first communication pipe 170 is communicated with the water outlet end 41 of the water outlet pipe 40. In this way, when the user does not use the water heater 100, the water flows between the water storage tank 160, the first communication pipe 170 and the bypass. The circulating flow between the pipes 60 or the flow between the water storage tank 160, the first communication pipe 170 and the heat exchanger 20 ensures that the water outlet pipe 40 has heat from the position connected with the water storage tank 160 to any position of the water outlet end 41. Water exists, and the next time the user uses hot water, the effect of zero waiting can be achieved, and hot water will flow out without waiting.

In one embodiment, the water heater 100 further includes a first temperature sensor for detecting the temperature of the water in the water pipe 40 . When it is detected that the water point has an input signal, the proportional valve 70 controllably adjusts the proportion of cold water flowing to the water outlet pipe 40 according to the difference between the temperature of the water in the water outlet pipe 40 and the preset temperature. That is, the proportional valve 70 adjusts the resistance on the bypass pipe 60 according to the difference between the temperature of the water in the water outlet pipe 40 detected by the first temperature sensor and the preset temperature, so as to adjust the cold water flowing from the water inlet pipe 30 to the water outlet pipe 40 ratio, so as to achieve the purpose of keeping the outlet water temperature of the outlet pipe 40 constant.

It can be understood that, in other embodiments, the water heater 100 may also be provided with a pressure valve, and the pressure valve is used to detect the water inlet pressure in the water inlet pipe 30 . When it is detected that the water point has an input signal, the proportional valve 70 can controllably adjust the proportion of cold water flowing to the water outlet pipe 40 according to the difference between the pressure in the water inlet pipe 30 and the preset pressure, which is not limited here.

The water heater 100 further includes a second communication pipe 190, and both ends of the second communication pipe 190 are communicated with the water outlet end 41 of the water outlet pipe 40 and the water inlet pipe 30, respectively. In this way, when it is detected that the water point has an input signal, that is, when the user uses water, the controller controls the on-off valve 90 to open, and the water inlet pipe 30 is communicated with the water source. The two communicating pipes 190 flow to the water outlet end 41 of the water outlet pipe 40 and then flow out after mixing. It can be understood that, in other embodiments, the water heater 100 may also omit the second communication pipe 190 .

In a specific embodiment, the first communication pipe 170 and the second communication pipe 190 have a common section, the first communication pipe 170 has a first section, the second communication pipe 190 has a second section, and one end of the common section is connected to the water inlet pipe 30 The two ends of the first section are respectively connected with the other end of the common section and the outlet pipe 40, the one-way valve 180 is assembled on the first section, and the two ends of the second section are respectively connected with the other end of the common section and the outlet pipe 40. The water outlet 41 is connected.

Referring to FIG. 2, an embodiment of the present invention further provides a control method for a water heater 100, including:

S110: when it is detected that the water point has an input signal, control the burner 10 to work and the water inlet pipe 30 to communicate with the water source;

S120 : Control the proportional valve 70 to adjust the proportion of cold water flowing from the water inlet pipe 30 to the water outlet pipe 40 .

In the control method of the water heater 100 provided by the embodiment of the present invention, the proportional valve 70 will controllably adjust the ratio of the cold water flowing from the water inlet pipe 30 to the water outlet pipe 40, so as to neutralize the cold water and the hot water to adjust the temperature of the water outlet from the water outlet pipe 40, so that the The temperature flowing out of the water outlet pipe 40 is kept constant, which reduces the phenomenon of sudden cold and sudden hot when water is used.

In one embodiment, when it is detected that the water point has no input signal and the temperature of the water in the water storage tank 160 is greater than or equal to the first preset threshold, the burner 10 is controlled to stop working and the water inlet pipe 30 is disconnected from the water source;

Control water flows between the water storage tank 160 , the bypass pipe 60 and the first communication pipe 170 .

Through the above arrangement, under the condition that the water storage tank 160 has a suitable temperature, the water does not flow through the heat exchanger 20, so as to reduce the resistance encountered when the water flows, reduce heat dissipation, and save energy.

In another embodiment, when it is detected that the water point has no input signal and the temperature of the water in the water storage tank 160 is lower than the first preset threshold, the burner 10 is controlled to work and the water inlet pipe 30 is disconnected from the water source;

Water is controlled to flow between the storage tank 160 , the bypass pipe 60 and the heat exchanger 20 .

Through the above arrangement, the flue gas generated by the combustion of the burner 10 can exchange heat with the water flowing in the heat exchanger 20 to ensure that the water in the water storage tank 160 is at a suitable temperature.

Specifically, the flow rate of the above-mentioned water flowing in the heat exchanger 20 is set to the flow rate corresponding to the combustion of the burner 10 with the minimum power, so as to avoid waste of resources.

Further, when it is detected that the water point has no input signal and the water level in the water storage tank 160 is lower than the second preset threshold, the water inlet pipe 30 is controlled to communicate with the water source, thereby ensuring that the water storage tank 160 has an appropriate amount of water.

Specifically, the water heater 100 includes a water level sensor, and the controller controls the water level sensor to detect the water level in the water storage tank 160 .

In one embodiment, when it is detected that the water point does not have an input signal for a period greater than a third preset threshold, the water heater 100 is controlled to stand by, thereby avoiding waste of resources. That is, the water heater 100 provided in this embodiment is suitable for the situation where the user turns off the water for a short time while using water; and when the user does not use water for a time period greater than the third preset threshold, the water heater 100 will be in a standby state and will no longer be used. It can be ensured that the water storage tank 160 has hot water of a suitable temperature.

Specifically, the above-mentioned third preset threshold may be set as required, for example, the third preset threshold may be set to 10-20 minutes. Of course, in other embodiments, the setting of the third preset threshold is not limited.

The technical features of the above-described embodiments can be combined arbitrarily. For the sake of brevity, all possible combinations of the technical features in the above-described embodiments are not described. However, as long as there is no contradiction between the combinations of these technical features, All should be regarded as the scope described in this specification.

The above-mentioned embodiments only represent several embodiments of the present invention, and the descriptions thereof are specific and detailed, but should not be construed as a limitation on the scope of the invention patent. It should be pointed out that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can also be made, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention should be subject to the appended claims.

Claims (15)

1. The water heater is characterized by comprising a burner (10), a heat exchanger (20), a water inlet pipe (30) and a water outlet pipe (40), wherein the water inlet pipe (30) and the water outlet pipe (40) are respectively communicated with the inlet end and the outlet end of the heat exchanger (20), and the burner (10) is used for burning to generate flue gas which exchanges heat with water in the heat exchanger (20);

the water heater also comprises a bypass pipe (60) and a proportional valve (70), wherein two ends of the bypass pipe (60) are respectively communicated with the water inlet pipe (30) and the water outlet pipe (40), and the proportional valve (70) is assembled on the bypass pipe (60);

when the water consumption point is detected to have an input signal, the water inlet pipe (30) is communicated with a water source, and the proportional valve (70) controllably adjusts the proportion of cold water flowing from the water inlet pipe (30) to the water outlet pipe (40) so as to keep the temperature of outlet water from the water outlet pipe (40) constant.

2. The water heater according to claim 1, further comprising a storage tank (160), said storage tank (160) communicating with said outlet pipe (40), said outlet pipe (40) communicating with said bypass pipe (60) through said storage tank (160);

when it is detected that the water consumption point has no input signal and the temperature of the water in the water storage tank (160) is less than a first preset threshold value, the water inlet pipe (30) is disconnected from the water source and the burner (10) works to exchange heat with the heat exchanger (20).

3. The water heater according to claim 2, further comprising a first communication pipe (170) and a check valve (180), both ends of the first communication pipe (170) are respectively communicated with the water inlet pipe (30) and the water outlet pipe (40), the check valve (180) is mounted on the first communication pipe (170) for restricting water from flowing from one end of the first communication pipe (170) communicated with the water inlet pipe (30) to one end thereof communicated with the water outlet pipe (40); the communication position of the first communication pipe (170) and the water outlet pipe (40) is positioned on one side of the water storage tank (160) far away from the heat exchanger (20);

wherein, when it is detected that the water usage point has no input signal and the temperature of the water in the storage tank (160) is less than a first preset threshold, the proportional valve (70) controllably adjusts the resistance of the water in the bypass pipe (60) to circulate the water between the storage tank (160), the bypass pipe (60) and the heat exchanger (20).

4. A water heater according to claim 3, characterized in that when it is detected that the water usage point has no input signal and the temperature of the water inside the storage tank (160) is greater than or equal to the first preset threshold, the proportional valve (70) controllably adjusts the resistance of the water inside the bypass pipe (60) to circulate the water between the storage tank (160), the first connection pipe (170) and the bypass pipe (60).

5. A water heater according to claim 3, wherein the communication of the first communication pipe (170) with the inlet pipe (30) is at the side of the communication of the bypass pipe (60) with the inlet pipe (30) remote from the heat exchanger (20).

6. A water heater according to claim 3, wherein the outlet pipe (40) has an outlet end (41), the first communication pipe (170) communicating with the outlet end (41) of the outlet pipe (40).

7. The water heater according to claim 1, further comprising a first temperature sensor for sensing the temperature of the water in the outlet pipe (40), the proportional valve (70) controllably adjusting the proportion of cold water flowing to the outlet pipe (40) in dependence on the difference between the temperature of the water in the outlet pipe (40) and a preset temperature when a water usage point is sensed with an input signal.

8. The water heater according to claim 1, wherein the outlet pipe (40) has an outlet end (41), the heat exchanger (20) further comprises a second communication pipe (190), and two ends of the second communication pipe (190) are respectively communicated with the outlet end (41) of the outlet pipe (40) and the inlet pipe (30).

9. The water heater according to claim 1, further comprising a water pump (110), the water pump (110) being mounted on the water inlet pipe (30) or the water outlet pipe (40).

10. The water heater according to claim 1, further comprising a controller, the burner (10) and the proportional valve (70) both being electrically connected to the controller.

11. A method of controlling a water heater, comprising:

when the water consumption point is detected to have an input signal, the work of the burner (10) is controlled, and the water inlet pipe (30) is communicated with a water source;

the proportion of cold water flowing from the water inlet pipe (30) to the water outlet pipe (40) is adjusted by controlling the proportion valve (70), so that the temperature of outlet water from the water outlet pipe (40) is kept constant.

12. The control method of a water heater according to claim 11,

when the water consumption point is detected to have no input signal and the temperature of the water in the water storage tank (160) is larger than or equal to a first preset threshold value, controlling the combustor (10) to stop working and the water inlet pipe (30) to be disconnected from a water source;

controlling water flow among the storage tank (160), the bypass pipe (60), and the first communication pipe (170).

13. The control method of a water heater according to claim 11,

when the water consumption point is detected to have no input signal and the temperature of the water in the water storage tank (160) is smaller than a first preset threshold value, controlling the combustor (10) to work and disconnecting the water inlet pipe (30) from a water source;

controlling water flow between the storage tank (160), the bypass pipe (60) and the heat exchanger (20).

14. The control method of a water heater according to claim 11,

when the water consumption point is detected not to have an input signal and the water level in the water storage tank (160) is lower than a second preset threshold value, the water inlet pipe (30) is controlled to be communicated with a water source.

15. The control method of the water heater according to any one of claims 11 to 14, wherein the water heater is controlled to be in a standby state when a period of time for which the water consumption point is detected to have no input signal is greater than a third preset threshold.

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