WO2025055735A1 - Water heater and control method - Google Patents

Abstract

The present invention relates to the field of water heaters, and in particular to a water heater and a control method. The water heater of the present invention comprises a housing, an inner tank, an instant heating unit, a heat storage and heating unit, a water flow switch, a control unit, a temperature sensor, a water inlet end and a water outlet end, and further comprises a heat exchanger and a pump, wherein the water inlet end, the heat exchanger, the instant heating unit and the water outlet end are sequentially connected to form an instant heating channel; the heat exchanger, the pump and the inner tank are connected to form a circulating heat exchange channel; the heat storage and heating unit is used for heating a heat storage medium in the inner tank; and the control unit controls working states of the instant heating unit, the heat storage and heating unit and the pump on the basis of one or more of a working mode, a water flow state and temperature of the water heater. The control method comprises: acquiring one or more of working mode, temperature and water flow state information of a water heater; on the basis of the acquired parameters, determining whether a pump needs to be started or not; if yes, controlling water outlet temperature by controlling the flow rate of pump; and if not, controlling the water outlet temperature by controlling the power of an instant heating unit.

Description

Water heater and control method Technical Field

The invention belongs to the field of water heaters, in particular to an electric water heater.

Background Art

Electric storage water heaters have high energy consumption, are not enough for multiple people to bathe, are large and unsightly, and scale accumulation affects water hygiene. The inner tank is under pressure and there is a risk of bursting. The alternating changes in high pressure and temperature cause microcracks in the enamel layer and corrosion, which causes stress corrosion in the stainless inner tank, etc. Instant water heaters have high power and cannot be installed in most families. In addition, the water volume is also small in winter with high power, and it is even more impossible to supply water in multiple ways at the same time, which results in a poor experience. Dual-mode fast-heating water heaters try to combine the advantages of the above two to make a compromise to solve the problem, but because the inner tank is small and the water temperature drops quickly, a thermostatic valve must be used to provide an acceptable bathing experience. Due to the influence of scale, sediment, high temperature and high pressure conditions, the thermostatic valve has a high failure rate that exceeds the market acceptance range. In addition, the inner tank capacity of the fast-heating water heater is small, and the impact of scale accumulation is large. In places with severe scale, half of the volume is filled in two or three years. The inner tank of the fast-heating water heater also has the same problems as the storage water heater. In order to solve the problems of scaling and inner tank corrosion in instant water heaters, heat exchange water heaters have appeared on the market. However, the existing heat exchange solutions have brought greater problems than traditional water heaters. Although the problem of scaling in the inner tank and heater has been solved, scaling will form in the heat exchange tubes, which will lead to poor heat exchange or even blockage, making it unusable, which is more fatal than the impact of storage type scaling. At the same time, there is a heat exchange temperature difference in the heat exchange water heater, and the efficiency is low. Since the heat exchanger is placed in the inner tank, there will be a stream of very hot water when the water is turned off and then turned on, and there is even a risk of scalding. Therefore, this type of water heater must also have a thermostatic valve to have a suitable experience. As mentioned above, the failure rate of the thermostatic valve is high.

The water heater of the present application has developed a new heat exchange solution and constant temperature technology based on a comprehensive and in-depth understanding of electric water heater products and the market, which solves the problems existing in the above-mentioned water heaters and has very practical significance.

Technical issues

In order to solve the deficiencies of the existing water heater technology, the present invention provides a new technical solution.

Technical Solutions

The purpose of the present invention is to solve the problem through the following technical solutions:

A water heater comprises an outer shell, an inner tank, an instant heating unit, a heat storage heating unit, a water flow switch, a control unit, a temperature sensor, a water inlet, a water outlet, and also comprises a heat exchanger and a pump. The water inlet, the heat exchanger, the instant heating unit, and the water outlet are connected in sequence to form an instant heating channel; the heat exchanger, the pump, and the inner tank are connected to form a circulating heat exchange channel; the heat storage heating unit is used to heat the heat storage medium in the inner tank; the control unit controls the working state of the instant heating unit, the heat storage heating unit, and the pump according to one or more of the working mode of the water heater, the water flow state, and the temperature.

Optionally, the inner pot is connected to the atmosphere and also includes a liquid level sensing unit and a water supply valve. The liquid level sensing unit is arranged on the inner pot or a component connected to the inner pot, and is used to sense the liquid level of the inner pot; the inner pot is connected to the instant heating channel through the water supply valve.

Furthermore, the water supply valve is connected to the inner tank through the heat exchanger, and is used to remove air in the heat exchanger and the pump when filling water.

Furthermore, it also includes a liquid level tube, the liquid level sensing unit is installed in the liquid level tube, and the liquid level tube is connected to the inner tank.

Optionally, it also includes a heat conducting sheet and a temperature control switch, wherein two ends of the heat conducting sheet are thermally coupled with the instant heating unit and the heat storage heating unit or the inner tank respectively, and the temperature control switch is installed on the heat conducting sheet.

Optionally, the control unit includes a speed regulating module, and the control unit controls the rotation speed of the pump according to a temperature parameter of the water heater to adjust the outlet water temperature.

Optionally, a flow regulating valve is further included, which is arranged on the circulating heat exchange channel. The control unit controls the opening of the flow regulating valve to control the flow of the pump, thereby controlling the water outlet temperature of the water heater.

Optionally, the pump is arranged at one end of the heat exchanger where water flows out.

A control method, the control method comprising:

Obtain one or more of the water heater's operating mode, temperature, and water flow status information;

Determine whether the pump needs to be started according to the acquired parameters;

If so, the outlet water temperature is controlled by controlling the pump flow rate;

If not, the outlet water temperature is controlled by controlling the power of the instant heating unit.

Optionally, the water heater parameters include one or more of the working mode, water flow switch state, water inlet temperature, inner tank temperature, and water outlet temperature, and the control method thereof includes the following steps:

Step 1: Get the working mode of the water heater. If it is instant heating mode, go to step 2; if it is quick heating mode, go to step 9;

Step 2: Is the water flow switch activated? If yes, proceed to step 3; if no, proceed to step 22;

Step 3: Is the instant heating unit started? If yes, go to step 5; if no, go to step 4;

Step 4, the instant heating unit is started, and then step 5 is performed;

Step 5. Is the outlet water temperature lower than the set outlet water temperature? If yes, proceed to step 6; if no, proceed to step 7;

Step 6: Increase the power of the instant heating unit, and then execute step 1;

Step 7. Is the outlet water temperature greater than the set outlet water temperature? If yes, proceed to step 8; if no, proceed to step 1;

Step 8, reduce the power of the instant heating unit, and then execute step 1;

Step 9. Is the water flow switch activated? If yes, proceed to step 10; if no, proceed to step 18;

Step 10: Is the inner tank temperature greater than the inlet water temperature plus a? If yes, go to step 11; if no, go to step 3;

Step 11: Is the instant heating unit working? If yes, go to step 13; if no, go to step 12;

Step 12, the pump and the instant heating unit work, and then execute step 13;

Step 13: Is the outlet water temperature lower than the set outlet water temperature? If yes, go to step 14; if no, go to step 15;

Step 14: Increase the pump flow rate, and then execute step 1;

Step 15. Is the outlet water temperature greater than the set outlet water temperature? If yes, go to step 16; if no, go to step 1;

Step 16: Is the pump started? If yes, go to step 17; if no, go to step 8;

Step 17, reduce the pump flow, and then execute step 1;

Step 18, the pump and the instant heater stop working, and then execute step 19;

Step 19: Is the inner tank temperature lower than the inner tank set temperature? If yes, go to step 20; if no, go to step 21;

Step 20, the heat storage and heating unit works, and then executes step 1;

Step 21, the heat storage and heating unit stops working, and then executes step 1;

Step 22: the heating unit stops working, and then executes step 1.

Beneficial Effects

The present application discloses a water heater and control method which are more hygienic, energy-saving, convenient, beautiful and safer than traditional electric storage water heaters; have lower circuit requirements than instant hot water heaters, are more adaptable to installation, and have a larger water volume; and achieve a constant temperature effect by adjusting the heat exchange flow rate, which is a new water heater temperature control method, is more stable and durable than traditional thermostatic valves, and has great promotion significance.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention is further described below with reference to the accompanying drawings and embodiments.

Figure 1 is a schematic diagram of the structure of a water heater.

Figure 2 is a schematic diagram of the structure of a water heater

Figure 3 is a schematic diagram of the structure of a water heater

Figure 4 is a schematic diagram of the structure of a water heater

Figure 5 is a schematic diagram of the structure of a water heater

FIG. 6 is a flow chart of a control method

Figure 7 is a logic diagram of a control method

In the figure:

1. Outer shell 2. Inner tank 3. Instantaneous heating unit 4. Thermal storage heating unit 5. Heat exchanger 501. Heat exchanger shell 502. Heat exchange tube 6. Pump 7. Control unit 8. Water flow switch 9. Temperature sensor 10. Liquid level sensing unit 11. Water supply valve 12. Circulating water inlet pipe 13. Circulating water outlet pipe 14. Water inlet end 15. Water outlet end 16. Flow regulating valve 17. Insulation layer 18. Liquid level tube 19. Exhaust hole 20. Connecting pipe 21. Heat conductive sheet 22. Temperature control switch.

Best Mode for Carrying Out the Invention

It should be noted that, under the premise of no conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present invention is further described below in conjunction with the drawings and embodiments.

Example

A water heater comprises an outer shell 1, an inner tank 2, an instant heating unit 3, a heat storage heating unit 4, a water flow switch 8, a control unit 7, a temperature sensor 9, a water inlet 14, a water outlet 15, and also comprises a heat exchanger 5 and a pump 6. The water inlet, the heat exchanger, the instant heating unit, and the water outlet are connected in sequence to form an instant heating channel; the heat exchanger, the pump, and the inner tank are connected to form a circulating heat exchange channel; the heat storage heating unit is used to heat the heat storage medium in the inner tank; the control unit controls the working state of the instant heating unit, the heat storage heating unit, and the pump according to one or more of the working mode of the water heater, the water flow state, and the temperature.

As shown in Figure 1, tap water enters the water heater from the water inlet 14, flows through the water flow switch 8, the heat exchanger 5, and the instant heating unit 3 in sequence, and flows out from the water outlet 15 after being heated by the instant heating unit. This path is the instant heating channel. Compared with ordinary instant water heaters, this part only has an additional heat exchanger at the front end of the instant heating unit. The heat storage medium in the inner tank 2 enters from the circulating water inlet pipe 12 under the drive of the pump 6, flows through the heat exchanger 5, transfers heat to the tap water in the instant heating channel, and then returns to the inner tank 2 through the pump 6 and the circulating water outlet pipe. In this way, the heat exchange cycle is performed, which is equivalent to preheating cold water. Since the temperature of the heat storage medium drops and the density decreases after heat exchange, it will sink to the bottom after entering the inner tank from the circulating water outlet pipe 13, pushing the hot heat storage medium to the top. In this way, within a certain period of time, the temperature of the heat storage medium flowing into the circulating water inlet pipe will be relatively stable. This type of external circulation heat exchange is much better than the structure of installing the heat exchanger in the inner tank for direct heat exchange. Although the heat exchanger is installed in the inner tank for direct heat exchange, the pump is omitted, but the temperature of the inner tank will continue to drop, resulting in unstable water outlet temperature. Even if a thermostatic valve is installed, the constant temperature control will be relatively troublesome. In addition, due to the heat exchange temperature difference, when water flows, the temperature of water flowing out of the heat exchanger is always lower than the heat exchange medium in the inner tank. It may even be dozens of degrees lower when there is no forced convection. When the water flow stops, the heat storage medium in the inner tank has enough time to keep the water in the heat exchanger at the same temperature. At this time, when the user turns on the shower, a stream of very hot hot water will come out, which is a very bad experience and there is a risk of scalding. Thirdly, since the tap water in the heat exchanger will eventually reach the same temperature as the heat storage medium in the inner tank, it will cause scale to form in the flow channel of the heat exchanger through which the tap water flows, making it impossible to use normally soon. However, in the external circulation heat exchange method shown in Figure 1, the above problems do not exist. When the water is turned off, the temperature of the hot medium in the heat exchanger and the cold water of the tap water is averaged, and the temperature is generally maintained below 50 degrees. Moreover, the heat exchanger will dissipate heat outward and will not reach the scaling condition. In Figure 1, the pump 6 is installed at the end of the water outlet of the heat exchanger. This is to make the heat storage medium flowing through the pump a low-temperature medium after releasing heat. The pump 6 is installed at the end of the water inlet of the heat exchanger 5, which is also within the protection scope of the present invention, but this installation method will cause the pump to withstand high temperatures, which is not good for the high-speed rotating impeller, magnets, and electronic components. The temperature of the heat storage medium in the inner tank will drop a lot after releasing heat energy through the heat exchanger 5. A heat exchanger with good performance will reduce the high-temperature hot water to only a few degrees higher than the cold water inlet of the water heater, so it is a better way to install the pump at the water outlet of the heat exchanger 5. The heat storage heating unit 4 is installed in the inner tank 2 to heat the heat storage medium in the inner tank. The heat storage medium can be water or other liquids such as oil. A temperature sensor 9 is installed on the water outlet 15 and in the inner tank 2 for sensing the temperature of the inner tank and the water outlet; the water flow switch 8 can be installed at any position of the entire instant heating channel, for example, it can also be set on the water outlet 15 to sense the water flow state; as shown by the dotted line in Figure 1, the water flow switch, temperature sensor, pump, instant heating unit, and heat storage heating unit are connected to the control unit 7 through wires. Under special circumstances, some components can also be wirelessly connected by electromagnetic waves and mechanical waves. The control unit intelligently controls the pump, instant heating unit, and heat storage heating unit as actuators according to the working mode, water flow state, and temperature parameters set by the water heater.

The inner tank 2 can adopt a pressure-bearing or non-pressure-bearing structure. If a pressure-bearing structure is adopted, a pressure relief device needs to be installed on the inner tank. The non-pressure-bearing structure needs to open a hole to communicate with the atmosphere. Both pressure-bearing and non-pressure-bearing inner tanks can be filled with heat storage medium manually or automatically. Manual filling can be done by opening a filling hole on the inner tank and injecting from the filling hole; or a manual valve can be set, one end of the valve is connected to the inner tank, and the other end is connected to tap water. The valve is opened manually for filling, and the valve is closed after visual filling. Automatic filling can be set between the tap water and the inner tank. A solenoid valve or a valve driven by a stepper motor is controlled by the control unit 7. Automatic filling can only inject tap water as a heat storage medium. The heat storage heating unit 4 can adopt a resistance heater or an electromagnetic heater. The resistance heater can be installed inside the inner tank 2 to directly heat the heat storage medium, such as using an electric heating tube, or it can be attached to the outer wall of the inner tank for indirect heating, such as a cast aluminum heating plate; while the electromagnetic induction coil of the electromagnetic heating device can only be set outside the inner tank.

The water heater in Figure 1 can have at least two heating modes, an instant heating mode and a rapid heating mode. When the instant heating mode is used, the heat storage heating unit 4 and the pump 6 do not work. At this time, the cold water entering the water heater will not obtain heat through the heat exchanger, and the tap water will only be heated by the instant heating unit 3. The control unit 7 can control the power of the instant heating unit to adjust the temperature of the outlet water. When the rapid heating mode is used, the heat storage heating unit 4 will heat the heat storage medium in the inner tank. When the water flow switch 8 senses that there is water flowing, the pump 6 starts, and the heat storage medium in the inner tank is extracted to preheat the tap water flowing through the heat exchanger through the heat exchanger 5. The preheated tap water is then heated again by the instant heating unit 3 and flows out. The rapid heating mode is used when the tap water temperature is low and the water heater cannot meet the bathing requirements by using only instant heating. These two heating modes are equivalent to combining the advantages of water storage type and instant heating type. When the tap water temperature is high, the heat storage medium in the inner tank does not need to store heat and can be used immediately after it is turned on, thus avoiding the heat dissipation loss of the water storage water heater; when the tap water temperature is low, the heat energy stored in the inner tank can be utilized, so that the instant heating unit only uses lower power to meet the bathing requirements of large water volume, solving the problem of high power and small water volume of instant water heaters; at the same time, since the instant heating unit of appropriate power plays a leading role, the capacity of the inner tank can be greatly reduced. Its capacity is only needed to assist the instant heating when the tap water temperature is low, making the water heater more beautiful and heating faster, so that multiple people can take turns to bathe.

Scaling of storage water heaters is a major industry problem. A large amount of scale accumulates in the inner tank, greatly affecting water hygiene and the life of the electric heating tubes. It also increases energy consumption, reduces the effective capacity of the water heater, and brings various adverse effects. The heat exchange structure shown in FIG. 1 can effectively solve this problem: 1. The inner tank 2 and the heat storage heating unit 4 will not produce scale. For a 30-liter water heater using the technology of the present invention, even if the heat storage medium in the inner tank is water with serious scale, since the water in the inner tank is not discharged for use, it is only used as a heat storage medium. After filling, only the evaporated water needs to be replenished. During the service life of about 8 years, the water entering the inner tank is expected to be about 80 liters, which is like the amount of scale generated by using an ordinary 80-liter water storage type once, which can be ignored; 2. The heat exchanger 5 is also difficult to scale. The temperature of the heat storage medium from the inner tank flowing through the heat exchanger is high, but for the same reason as the inner tank, the scale can be ignored; the tap water flowing through the heat exchanger has a low temperature and a fast flow rate, which cannot meet the scaling conditions; 3. If the instant heating unit 3 uses a cast aluminum heater, according to more than ten years of experience in the instant water heater industry, it will not produce scale. Heat exchange methods are also widely used in water heaters. For example, a multi-mode water heater adopts a heat exchange method. However, since the heat exchanger is placed in the inner tank, scaling occurs in the heat exchange tube, causing the heat exchanger to lose its heat exchange function or even block the heat exchanger. At the same time, the heat exchanger placed in the inner tank also causes the problem of scalding water when the water is turned off and then on again, which seriously affects the user experience. Even if a thermostatic valve is used, the thermostatic process is prolonged, resulting in a poor experience. The heat exchanger is placed in the inner tank, causing the overall temperature of the inner tank to continue to drop, causing the outlet water temperature of the water heater to continue to drop, requiring frequent adjustment of the hot and cold water mixing ratio. Placing the heat exchanger in the inner tank also causes inconvenience in maintenance. The present invention places the heat exchanger outside the inner tank. Although a pump is added, the above problems are fully solved. At the same time, the outlet water temperature of the water heater can be controlled by adjusting the flow rate of the pump, so that the water heater does not need a thermostatic valve to adjust the temperature. The increased cost of the pump is offset by the thermostatic valve, so this solution is extremely cost-effective.

Pump 6 can be a speed-adjustable pump or a common non-speed-adjustable pump. If the speed cannot be adjusted, the outlet water temperature of the water heater cannot be controlled by adjusting the flow rate, or the outlet water temperature can only be controlled by adding a flow regulating valve to adjust the flow rate of the heat storage medium. Of course, if the flow rate of the pump is not relied on for temperature adjustment in the rapid heating mode, the outlet water temperature can also be adjusted by controlling the power of the instant heating unit 3 or the flow rate of tap water, but this method will reduce the hot water output of the water heater, because the power of the instant heating unit cannot be fully used; or the adaptability to different water pressures is not good, such as fixing a suitable pump flow rate, when the user's tap water pressure is high, the tap water flow rate is large, and the tap water after heat exchange cannot reach the set outlet water temperature even if it is heated by the instant heating unit at full power. At this time, the user only needs to manually reduce the flow rate. This situation is also the same when there are multiple water supplies. If the pump can adjust the flow rate, it only needs to increase the pump flow rate at this time. Therefore, when the heat exchanger is needed to preheat the tap water in the rapid heating mode, it is a better solution to control the water outlet temperature of the water heater by adjusting the flow of the pump, so that the instant heating unit 3 can be at maximum power. At this time, at a certain flow rate and water outlet temperature, the flow rate of the heat storage medium pumped out of the inner tank by the pump is the smallest, so the water use time is long and the hot water output is the largest.

Example

The inner pot of this embodiment is connected to the atmosphere, and further comprises a liquid level sensing unit 10 and a water supply valve 11. The liquid level sensing unit is arranged on the inner pot or a component connected to the inner pot, and is used to sense the liquid level of the inner pot; the inner pot is connected to the instant heating channel through the water supply valve. It also comprises a heat conducting sheet 21 and a temperature control switch 22. The two ends of the heat conducting sheet are respectively thermally coupled with the instant heating unit 3 and the heat storage heating unit 4 or the inner pot 2, and the temperature control switch is installed on the heat conducting sheet.

As shown in FIG2 , an exhaust hole 19 is added to the inner tank 2 to communicate with the atmosphere, and a liquid level sensing unit 10 is arranged on the top of the inner tank to sense the liquid level of the heat storage medium in the inner tank, and to transmit a signal to the control unit 7 to play one or more functions such as prompting, controlling automatic water replenishment, and preventing dry burning. In FIG2 , one end of the water supply valve 11 is connected to the water inlet end 14, and the other end is connected to the heat exchanger 5. The position of the connection with the heat exchanger should be considered to be conducive to exhausting the air in the heat exchanger and the pump 6. If there is too much air, the pump 6 may not be able to suck the heat storage medium in the inner tank. The purpose of the water supply valve 11 is to add water to the inner tank 2. It can be a manual valve or an automatic valve. If a manual valve is used, when the liquid level sensing unit 10 senses that the liquid level is too low, sound, light, etc. can be used to remind the user to add water; if an automatic valve is used, when the liquid level sensing unit 10 senses that the liquid level is too low, the water supply valve 11 automatically replenishes water and automatically shuts off when it is full. The installation position of the water supply valve only needs to connect the inner tank to the tap water, but if it is connected to the rear end of the water flow switch 8, the water flow switch will also sense the water flow when the inner tank is replenished with water, which will be confused with the user's water use. If the instant heating unit is started at this time, it will cause dry burning. This problem can be avoided through software design. For example, when the liquid level sensing unit senses that the liquid level is low, the instant heating unit will not work.

As shown in Figure 2, the heat exchanger 5 includes a heat exchanger shell 501 and a heat exchange tube 502. It is a shell and tube heat exchanger. This type of heat exchanger has a simple structure and low cost, but the heat exchange efficiency is poor due to laminar flow. It is not as good as the shell and tube type, which is also a shell and tube heat exchanger, but the shell and tube type has a high cost. Also, due to the laminar flow, the heat exchange efficiency is not high, but it is much better than the heat exchanger shown in the figure. Considering performance, economy, and compactness of structure, a plate heat exchanger can be selected. The schematic diagram of the present invention is only for simplicity and clarity, so the simplest shell and tube heat exchanger is used as a schematic diagram in the figure, which cannot be used as a limitation of the present invention.

As shown in FIG3 , it also includes a liquid level tube 18, in which the liquid level sensing unit 10 is installed, and the liquid level tube is connected to the inner tank 2. This structure makes it unnecessary for the liquid level sensing unit to withstand the high temperature of the inner tank, so that the component has better reliability and longer service life. The liquid level sensing in FIG3 adopts a float switch, and uses a magnet to act on a reed switch or a Hall switch to achieve liquid level sensing. Such float switches all achieve electrical isolation and can meet the protection requirements of Class II electrical appliances, but the float switch may have problems such as the float stuck or the reed switch or Hall element failure, and there is also the problem of magnet demagnetization. If the liquid level sensing adopts electrode sensing as shown in FIG4 , it is simpler and more reliable than the float switch, but the disadvantage of electrode sensing is that there may be a risk of leakage. Although the electrode uses a few volts of weak electricity, there may also be a risk of leakage due to transformer damage, strong and weak current bridging, and lightning strikes. As shown in FIG. 4 , a slender and insulated connecting tube 20 is added, so that a sufficiently large resistor composed of heat storage medium is connected in series between the inner tank and the liquid level sensing unit, so that even if the liquid level sensing unit 10 is charged with a voltage of 220 volts, it will not pose a safety hazard to the user.

As shown in Figure 2, the water heater of the present invention includes two heaters, an instant heating unit and a heat storage heating unit. Considering safety, the electronic components may fail, and the contacts of the relay may spark and weld, thereby causing the temperature control to fail. Therefore, a mechanical temperature control switch with manual reset needs to be set on each heater or the inner tank associated with the heater to prevent the heating from getting out of control, which is used as the last insurance when the electronic components fail. However, if two temperature control switches are installed, not only the cost increases, but also the failure rate increases exponentially. Therefore, as shown in Figure 2, the two heaters are directly or indirectly connected by a heat conducting sheet 21, and the temperature control switch 22 is installed on the heat conducting sheet. In this way, if any one of the two heating units is too high, the temperature control switch will play a protective role. Of course, the heat conducting sheet is connected to one end of the heat storage heating unit 4, and can also be connected to the inner tank, as long as the temperature is well transmitted.

A temperature sensor 9 is installed on the water inlet end 14 of Figure 2 for sensing the inlet temperature of tap water. According to the inlet temperature, the water heater can automatically determine whether to use instant heating or rapid heating mode, to what degree the inner tank temperature is heated, and whether the pump is started, thereby achieving more intelligent control.

As shown in Fig. 5, a flow regulating valve 16 is also included. The flow regulating valve is arranged on the circulating heat exchange channel. The control unit controls the opening of the flow regulating valve to control the flow of the pump, thereby controlling the outlet water temperature of the water heater. When the flow rate is not accurately or economically adjusted by the speed regulating pump, a valve can be used to adjust the flow rate, thereby achieving the purpose of adjusting the outlet water temperature.

Example

The water heaters in the above two embodiments require a new control method to better exert the technical advantages brought by the structural innovation. This embodiment introduces a control method. First of all, it should be stated that the control method in the present invention only controls the structural innovation part of the present invention, and does not include a complete control method for the water heater. As shown in Figure 6, the control method includes but is not limited to the following steps:

Obtain one or more of the water heater's operating mode, temperature, and water flow status information;

Determine whether the pump needs to be started according to the acquired parameters;

If so, the outlet water temperature is controlled by controlling the pump flow rate;

If not, the outlet water temperature is controlled by controlling the power of the instant heating unit.

The working modes of the water heater of the present invention may include intelligent mode, instant heating mode, and rapid heating mode. The intelligent mode automatically selects the instant heating mode or the rapid heating mode according to the inlet water temperature and automatically sets the temperature of the inner tank. Therefore, the intelligent mode is not displayed in FIG. 7 .

A more specific control method is given below, wherein the part about liquid level control is not within the scope of the present invention, so the control method about liquid level control and low liquid level protection is omitted. As shown in FIG7 , Tn is the actual temperature of the inner tank, Tns is the set temperature of the inner tank, Tc is the actual outlet water temperature, Tcs is the set outlet water temperature, Tj is the inlet water temperature, and a is an arbitrary real number.

S201, after the water heater is powered on, first obtain the working mode of the water heater, if it is instant heating mode, execute S202; if it is rapid heating mode, execute S212;

S202, instant heating mode, execute S203;

S203, determining whether water is flowing in the water heater, if so, executing S204, if not, executing S205;

S204, determine whether the instant heating unit is already in working state, if yes, execute S207; if not, execute S206; since the parameters of the water heater are in dynamic change, for example, the user may adjust the working mode of the water heater, the water outlet temperature, the tap water may suddenly stop supplying water, etc., the program is always in a loop state, and can respond in time when the parameters change. The step S204 is to determine whether it is the first cycle of the water heater just turning on the water or a subsequent cycle. If it is the first time, the instant heating unit needs to be started. If it is a subsequent cycle, it is only necessary to consider whether the power needs to be adjusted to make the water outlet temperature close to the set water outlet temperature.

S205, stopping the instant heating unit, and then executing S208; if the instant heating unit is originally in a closed state, maintaining the closed state.

S206, start the instant heating unit, and then execute S207;

S207, comparing whether the actual outlet water temperature is less than the set outlet water temperature, if yes, executing S209 to increase the power of the instant heating unit; if no, executing S210, comparing whether the actual outlet water temperature is greater than the set outlet water temperature;

S208, execute S201, return to the program starting position to start the next cycle;

S209. Increase the power of the instant heater. How much to increase it at a time depends on the actual test results and is also related to the time interval between two program cycles. In short, the thermal lag problem must be taken into account. After the heater adjusts its power, it will take a certain amount of time for the water temperature to reflect it. Therefore, if the cycle speed is fast, the wattage of the power should be low each time. Otherwise, the water temperature will be hot and cold and will never be adjusted to the right temperature.

S210, compare whether the actual water outlet temperature is greater than the set water outlet temperature. If so, execute S211 to reduce the power of the instant heating unit; if not, execute S228; in S207, it has been compared whether it is less than, and in S210, it is compared whether it is greater than. If both times are no, it must be equal to, which proves that the current actual water outlet temperature is equal to the set water outlet temperature, and there is no need to adjust the power of the instant heating unit.

S211, reducing the power of the instant heating unit, and then executing S228;

S212, rapid heating mode, execute S213; the so-called rapid heating mode is a working mode in which the inner tank of the water heater needs to store heat to provide auxiliary heat to the instant heating unit.

S213, determining whether water is flowing in the water heater, if so, executing S215, if not, executing S214;

S214, turn off the pump and the instant heating unit; if the pump and the instant heating unit are originally in the off state, maintain the off state, and then execute S217;

S215, determine whether the inner tank temperature is greater than the inlet water temperature plus a, if yes, execute S218; if not, execute S216; the inner tank temperature must be higher than the inlet water temperature for heat exchange to be meaningful, and how much higher it is depends on the heat exchange effect of the heat exchanger, so a can be determined based on actual test data. If the inner tank temperature is low, heat exchange is meaningless, so even in the quick heating mode, the pump will not start, and at this time the instant heating mode program can be called to control the operation of the water heater.

S216, execute S204;

S217, determine whether the inner tank temperature is less than the inner tank setting temperature, if yes, execute S224; if no, execute S221; in the actual control program, whether the inner tank temperature is less than the inner tank setting temperature should be added with a, otherwise it will cause frequent heating, such as the inner tank is set to 80 degrees, and the inner tank temperature is lower than 75 degrees before heating, etc. This control method only gives the control logic of the water heater based on the present invention, and does not involve the details of the actual program.

S218, determine whether the instant heating unit is already in operation, if so, execute S220; if not, execute S219; if at this step, if the instant heating unit is not started, it proves that the program is in the first cycle after the water flow is turned on, and the pump must not be started at this time. If the instant heating unit is already started at this step, it proves that it is not the first cycle, and at this time, it only needs to consider whether the outlet water temperature is equal to the set outlet water temperature.

S219, start the pump and the instant heating unit; generally, in the fast heating mode, the instant heating unit uses the set maximum power to work at startup. The so-called maximum power is the power set by the user. For example, some users worry about the large line load and set the power low. If it is not set, it is the rated power, that is, the maximum power of the water heater. Of course, considering the use of the maximum setting power at startup is only for the purpose of increasing the output of hot water. It is hoped that the instant heating unit will work at the maximum power and adjust the outlet water temperature by adjusting the flow of the pump. The heat taken from the inner tank is the least, so the use time is longer. If the output of hot water is not considered, there is no need to consider this, and the pump does not need to adjust the flow. In the fast heating mode, the outlet water temperature is adjusted by adjusting the power of the instant heating unit. There is no need to consider the constant temperature of the outlet water. The user can adjust the water flow size or the ratio of cold and hot water by himself, which is within the protection scope of the present invention. This control method only provides a better solution.

S220, determining whether the outlet water temperature is lower than the set outlet water temperature, if so, executing S223 to increase the flow rate of the pump; if not, executing S222;

S221, turn off the heat storage and heating unit, and then execute S228;

S222, determine whether the outlet water temperature is greater than the outlet water setting temperature. If so, execute S225; if not, execute S228; if the results of the comparison of steps S220 and S222 are both no, the actual outlet water temperature must be equal to the outlet water setting temperature, and the program does not need to perform temperature adjustment operations and can directly return to the next cycle.

S223, increase the flow rate of the pump, and then execute S228; the size of each increase or decrease in the flow rate of the pump must also be determined according to the speed of the program cycle, otherwise the outlet water temperature will fluctuate due to the thermal feedback delay of the heat exchange system and the temperature sensor and cannot be stable.

S224, starting the heat storage heating unit; starting the heat storage heating unit is to heat the heat storage medium of the inner tank.

S225, determine whether the pump has been started, if so, execute S227 to reduce the flow of the pump; if not, execute S226 to reduce the power of the instant heating unit; the purpose of this step is that if the flow of the pump has been shut down and the outlet water temperature is still high, the outlet water temperature can only be controlled by reducing the power of the instant heating unit.

S226, execute S211;

S227, reducing the flow rate of the pump;

S228. Execute S201.

The above control method is only one of many available control methods. More specific control methods can be designed based on the flowchart of FIG. 6 , all of which are within the protection scope of the present invention.

The above examples are not exhaustive of all structures and methods. The combination of all the above solutions, any solution that can be easily thought of through the present invention, and any modified solution are all within the protection scope of this patent.

Claims (10)

A water heater, comprising a shell (1), an inner tank (2), an instant heating unit (3), a heat storage unit (4), a water flow switch (8), a control unit (7), a temperature sensor (9), a water inlet (14), and a water outlet (15), characterized in that it also comprises a heat exchanger (5) and a pump (6), wherein the water inlet, the heat exchanger, the instant heating unit, and the water outlet are connected in sequence to form an instant heating channel; the heat exchanger, the pump, and the inner tank are connected to form a circulating heat exchange channel; the heat storage unit is used to heat the heat storage medium in the inner tank; and the control unit controls the working state of the instant heating unit, the heat storage unit, and the pump according to one or more of the working mode of the water heater, the water flow state, and the temperature. A water heater according to claim 1, characterized in that: the inner tank is connected to the atmosphere, and further comprises a liquid level sensing unit (10) and a water supply valve (11), wherein the liquid level sensing unit is arranged on the inner tank or a component connected to the inner tank, and is used to sense the liquid level of the inner tank; the inner tank is connected to the instant heating channel via the water supply valve. A water heater according to claim 2, characterized in that: the water supply valve (11) is connected to the inner tank through the heat exchanger, and is used to remove air in the heat exchanger and the pump when filling water. The water heater according to claim 2, characterized in that it further comprises a liquid level tube (18), wherein the liquid level sensing unit is installed in the liquid level tube, and the liquid level tube is connected to the inner tank (2). A water heater according to claim 1, characterized in that it also comprises a heat conducting sheet (21) and a temperature control switch (22), wherein two ends of the heat conducting sheet are thermally coupled to the instant heating unit (3) and the heat storage heating unit (4) or the inner tank (2), respectively, and the temperature control switch is mounted on the heat conducting sheet. A water heater according to claim 1, characterized in that: the control unit (7) comprises a speed regulating module, and the control unit controls the speed of the pump according to the temperature parameter of the water heater to adjust the outlet water temperature. A water heater according to claim 1, characterized in that it also includes a flow regulating valve (16), wherein the flow regulating valve is arranged on the circulating heat exchange channel, and the control unit controls the opening of the flow regulating valve to control the flow rate of the pump, thereby controlling the water outlet temperature of the water heater. The water heater according to claim 1, characterized in that the pump (6) is arranged at the water outlet end of the heat exchanger (5). A control method for a water heater according to any one of claims 1 to 8, characterized in that the control method comprises: Obtain one or more of the water heater's operating mode, temperature, and water flow status information; Determine whether the pump needs to be started according to the acquired parameters; If so, the outlet water temperature is controlled by controlling the pump flow rate; If not, the outlet water temperature is controlled by controlling the power of the instant heating unit. A control method according to claim 9, characterized in that: the water heater parameters include one or more of the working mode, the water flow switch state, the water inlet temperature, the water tank temperature, and the water outlet setting temperature, and the control method comprises the following steps: Step 1: Get the working mode of the water heater. If it is instant heating mode, go to step 2; if it is quick heating mode, go to step 9; Step 2: Is the water flow switch activated? If yes, proceed to step 3; if no, proceed to step 22; Step 3: Is the instant heating unit started? If yes, go to step 5; if no, go to step 4; Step 4, the instant heating unit is started, and then step 5 is performed; Step 5. Is the outlet water temperature lower than the set outlet water temperature? If yes, proceed to step 6; if no, proceed to step 7; Step 6: Increase the power of the instant heating unit, and then execute step 1; Step 7. Is the outlet water temperature greater than the set outlet water temperature? If yes, proceed to step 8; if no, proceed to step 1; Step 8, reduce the power of the instant heating unit, and then execute step 1; Step 9. Is the water flow switch activated? If yes, proceed to step 10; if no, proceed to step 18; Step 10: Is the inner tank temperature greater than the inlet water temperature plus a? If yes, go to step 11; if no, go to step 3; Step 11: Is the instant heating unit working? If yes, go to step 13; if no, go to step 12; Step 12, the pump and the instant heating unit work, and then execute step 13; Step 13: Is the outlet water temperature lower than the set outlet water temperature? If yes, go to step 14; if no, go to step 15; Step 14: Increase the pump flow rate and then execute step 1; Step 15. Is the outlet water temperature greater than the set outlet water temperature? If yes, go to step 16; if no, go to step 1; Step 16: Is the pump started? If yes, go to step 17; if no, go to step 8; Step 17, reduce the pump flow, and then execute step 1; Step 18, the pump and the instant heater stop working, and then execute step 19; Step 19: Is the inner tank temperature lower than the inner tank set temperature? If yes, go to step 20; if no, go to step 21; Step 20, the heat storage and heating unit works, and then executes step 1; Step 21, the heat storage and heating unit stops working, and then executes step 1; Step 22: the heating unit stops working, and then executes step 1.