Gas water heater and control method thereof

Abstract

This invention relates to a gas water heater and its control method. The gas water heater includes a heat exchanger, a cold water pipe, a hot water pipe, an inlet pipe, an outlet pipe, a temperature sensor, and an automatic thermostat. The automatic thermostat includes a tank, a baffle, and a drive mechanism. The control method of this invention includes: acquiring the water temperature in the inlet pipe; if the water temperature in the inlet pipe is lower than a preset temperature value, controlling the gas water heater to enter an anti-freeze mode. In the anti-freeze mode, the drive mechanism is controlled to move the baffle back and forth at a preset minimum speed in the arrangement direction of the first and second sub-spaces. When the baffle moves towards the second sub-space, the water in the second sub-space flows sequentially through the hot water pipe, the heat exchanger, and the cold water pipe before flowing into the first sub-space. Conversely, when the baffle moves towards the first sub-space, the water in the first sub-space flows sequentially through the cold water pipe, the heat exchanger, and the hot water pipe before flowing into the second sub-space. This prevents the gas water heater from freezing.

Description

Technical Field

[0001] This invention relates to the field of water heater technology, and in particular to a gas water heater and its control method. Background Technology

[0002] Currently, gas water heaters on the market experience a process where, after the water valve is closed and reopened, the water goes through a cycle of high-temperature hot water, cold water, and then room-temperature hot water. This phenomenon is known as the "sandwich effect" or "intercalated water." In other words, after restarting, the water heater needs time to stabilize at the set bathing temperature, significantly impacting user comfort. The main reason for this problem is that after the water valve is closed, the residual heat from the heat exchanger continues to heat the water stored inside the unit, making its temperature higher than the set temperature. When the water valve is reopened, this high-temperature stored water flows out first, forming hot water. The water heater uses the water flow signal as its start-up signal, so it only ignites and begins working when water flow is generated after the valve is reopened. There is a time lag between the water heater receiving the flow signal and the water reaching the set temperature. During this time, the flowing water is not heated before flowing out of the valve, creating a certain amount of cold water.

[0003] The following methods are commonly used in existing technologies to solve the aforementioned technical problems. First, adding a mixing device; some gas water heaters currently have a mixing tank at the outlet pipe. When the user uses hot water, some hot water is stored in the mixing tank. When the water supply is briefly interrupted and then restarted, the water in the outlet pipe mixes with the hot water in the tank before flowing out together. Second, adding an electric heating module; by adding an electric heating module to the gas water heater, when the water valve is briefly closed and then restarted, the flowing cold water is heated by the electric heating module, thus eliminating the cold water in the interlayer. Third, using energy storage materials; during normal hot water use, the energy storage material absorbs heat. When the water valve is briefly closed and then restarted, the energy storage material releases the stored heat to heat the flowing cold water.

[0004] However, electric heating modules are costly to develop, have complex control programs, and are susceptible to scale buildup from water ions, leading to a significant decrease in heating efficiency over time. Energy storage materials are expensive, the technology is immature, and their performance does not yet meet usage requirements; they remain theoretical and have not been put into practical use. Therefore, the lowest-cost and simplest solution currently is the mixing tank solution. However, existing mixing tank solutions simply connect a large water tank to the end of the outlet pipe, resulting in an unreasonable structural design. This limits the flow of hot water from the mixing tank, leading to poor mixing and an ineffective solution for cold water. Furthermore, when the ambient temperature is low, parts of the gas water heater may freeze, posing a risk of damage. Summary of the Invention

[0005] One objective of the first aspect of this invention is to overcome at least one deficiency of the prior art and to provide a control method that can prevent gas water heaters from freezing.

[0006] A further objective of the first aspect of the present invention is to prevent the ignition system from starting frequently and to reduce the user's water usage waiting time.

[0007] The second objective of this invention is to provide a gas water heater that has good water mixing performance and is not prone to freezing.

[0008] According to a first aspect of the present invention, the present invention provides a control method for a gas water heater, the gas water heater comprising a heat exchanger, a cold water pipe connected to the upstream side of the heat exchanger, a hot water pipe connected to the downstream side of the heat exchanger, an inlet pipe for connecting to a tap water pipe, an outlet pipe for connecting to a water user, a temperature sensor for acquiring the water temperature in the inlet pipe, and an automatic thermostat, the automatic thermostat comprising a tank, a drive mechanism, and a baffle disposed in the tank;

[0009] The baffle divides the space inside the tank into a fluid-isolated first subspace and a second subspace; the drive mechanism is connected to the baffle and is configured to controllably move the baffle along the arrangement direction of the first and second subspaces to adjust the volume of the first and second subspaces; wherein

[0010] The inlet pipe is connected to the first subspace, the hot water pipe and the outlet pipe are both connected to the second subspace, and the cold water pipe is configured to switch from being connected to the second subspace to being connected to the first subspace when water is used at the water-using end, and to switch from being connected to the first subspace to being connected to the second subspace when water is used at the water-using end; and

[0011] The control method includes:

[0012] Obtain the water temperature inside the inlet pipe; and

[0013] If the water temperature in the inlet pipe is lower than the preset temperature value, the gas water heater is controlled to enter the anti-freeze mode; wherein

[0014] In the antifreeze mode, the drive mechanism is controlled to move the baffle back and forth in the arrangement direction of the first subspace and the second subspace at a preset minimum speed. When the baffle moves toward the second subspace, the water in the second subspace flows sequentially through the hot water pipe, the heat exchanger, and the cold water pipe before flowing into the first subspace. When the baffle moves toward the first subspace, the water in the first subspace flows sequentially through the cold water pipe, the heat exchanger, and the hot water pipe before flowing into the second subspace.

[0015] Optionally, if the water temperature in the inlet pipe is lower than the preset temperature value, the control method further includes:

[0016] A warning message is issued indicating that the gas water heater is at risk of freezing.

[0017] Optionally, a heating device is provided in the second subspace; and

[0018] If the water temperature in the inlet pipe is higher than the preset temperature value, the control method further includes:

[0019] Obtain the water temperature in the second subspace;

[0020] Calculate the temperature difference between the set temperature of the gas water heater and the water temperature;

[0021] If the temperature difference is greater than the preset temperature difference value, the heating device is activated to heat the water in the second subspace until the water temperature in the second subspace reaches the set temperature.

[0022] Optionally, the gas water heater further includes a solenoid valve disposed within the cold water pipe to adjust the flow area of ​​the cold water pipe; and

[0023] If the temperature difference is less than or equal to the preset temperature difference value, the control method further includes:

[0024] Receive a water usage start signal, the water usage start signal being used to indicate that the water user has started water usage;

[0025] Adjust the opening degree of the solenoid valve to a preset minimum opening degree; wherein

[0026] The preset minimum opening is set so that the water flow in the cold water pipe is just enough to trigger the ignition system of the gas water heater to start.

[0027] Optionally, the drive mechanism includes a motor located outside the tank, a helical rod connected to the motor and extending into the tank, and a telescopic rod selectively retracting into or extending from the helical rod, the end of the telescopic rod being connected to the baffle; and

[0028] After adjusting the opening of the solenoid valve to a preset minimum opening, the control method further includes:

[0029] Receive an ignition start signal, which is generated when the water flow rate in the cold water pipe reaches the preset ignition flow rate;

[0030] Start the ignition system and control the motor to rotate in the forward direction;

[0031] Obtain the water flow rate in the outlet pipe;

[0032] Adjust the opening of the solenoid valve according to the water flow rate in the outlet pipe until the opening of the solenoid valve reaches the preset maximum opening; and

[0033] The speed of the motor is adjusted according to the water flow rate in the outlet pipe and the opening degree of the solenoid valve, so as to adjust the speed of the baffle movement until the baffle moves to the preset position.

[0034] Optionally, the step of adjusting the opening degree of the solenoid valve according to the water flow rate of the outlet pipe includes:

[0035] The opening degree of the solenoid valve is calculated using the following formula:

[0036] y t = k×t + y0; where

[0037] y t The value represents the opening degree of the solenoid valve at time t after receiving the ignition start signal, where t represents the water usage time since receiving the ignition start signal, y0 represents the preset minimum opening degree, and k represents a coefficient proportional to the user's water consumption.

[0038] Optionally, the step of adjusting the motor speed according to the water flow rate in the outlet pipe and the opening degree of the solenoid valve to adjust the speed of the baffle movement includes:

[0039] The water flow rate in the cold water pipe is calculated based on the opening degree of the solenoid valve;

[0040] Calculate the flow rate difference between the water flow rate in the outlet pipe and the water flow rate in the cold water pipe;

[0041] The target moving speed of the baffle is calculated using the following formula:

[0042] Q0 = (Q1 - Q2) / S; where Q0 represents the flow difference, Q1 represents the water flow rate in the outlet pipe, Q2 represents the water flow rate in the cold water pipe, and S represents the cross-sectional area of ​​the tank.

[0043] Calculate the target rotational speed of the motor based on the target moving speed of the baffle; and

[0044] Control the motor to run at the target speed.

[0045] Optionally, after the solenoid valve reaches the preset maximum opening degree, the control method further includes:

[0046] Receive a water usage stop signal, the water usage stop signal being used to indicate that the water-using end has stopped using water; and

[0047] The opening degree of the solenoid valve is adjusted to a preset initial opening degree, and the motor is controlled to rotate in the reverse direction; wherein

[0048] The preset initial opening degree is greater than zero and less than the preset minimum opening degree.

[0049] Optionally, after receiving the water use stop signal, the control method further includes:

[0050] Receive an ignition stop signal, which is generated when the water flow rate in the cold water pipe is less than the preset ignition flow rate; and

[0051] Stop the ignition system.

[0052] Optionally, the preset ignition flow rate is set to be greater than the maximum water flow rate in the cold water pipe when the cold water pipe is connected to the second subspace, and equal to or less than the minimum water flow rate in the cold water pipe when the cold water pipe is connected to the first subspace.

[0053] According to a second aspect of the present invention, the present invention also provides a gas water heater, comprising a heat exchanger, a cold water pipe connected to the upstream side of the heat exchanger, a hot water pipe connected to the downstream side of the heat exchanger, an inlet pipe for connecting to a tap water pipe, an outlet pipe for connecting to a water user, and an automatic thermostat, the automatic thermostat comprising a tank, a baffle and a temperature sensor disposed in the tank, and a drive mechanism.

[0054] The baffle divides the space inside the tank into a fluid-isolated first subspace and a second subspace; the drive mechanism is connected to the baffle and is configured to controllably drive the baffle to move along the arrangement direction of the first subspace and the second subspace to adjust the volume of the first subspace and the second subspace;

[0055] The inlet pipe is connected to the first subspace, the hot water pipe and the outlet pipe are both connected to the second subspace, and the cold water pipe is configured to switch from being connected to the second subspace to being connected to the first subspace when water is used at the water-using end, and to switch from being connected to the first subspace to being connected to the second subspace when water is used at the water-using end; and

[0056] The gas water heater also includes a control device, which includes a processor and a memory. The memory stores a machine-executable program, and when the machine-executable program is executed by the processor, it is used to implement the control method described in any of the above schemes.

[0057] The control method of this invention is based on a gas water heater with a special structure and features an anti-freeze mode specifically designed for low inlet water temperatures. In anti-freeze mode, a drive mechanism moves a baffle back and forth at a preset minimum speed along the arrangement of the first and second sub-spaces. When the baffle moves towards the second sub-space, it compresses the second sub-space, causing the relatively warmer water within it to flow sequentially through the hot water pipe, heat exchanger, and cold water pipe before flowing into the first sub-space, where it neutralizes the cooler water in the first sub-space and the inlet pipe connected to it. Conversely, when the baffle moves towards the first sub-space, it compresses the first sub-space, causing the water within it to flow sequentially through the cold water pipe, heat exchanger, and hot water pipe before flowing into the second sub-space. This process is repeated multiple times, effectively raising the temperatures of locations without stored hot water, such as the hot water pipe, heat exchanger, cold water pipe, and the first sub-space, thus preventing freezing at these locations.

[0058] Furthermore, this invention monitors the water temperature in the second sub-space when the gas water heater is in non-freezing mode, and uses a heating device to maintain the water temperature in the second sub-space close to the set temperature of the gas water heater. Further, after water usage begins at the user's end, the opening of the solenoid valve is adjusted to a preset minimum opening. On the one hand, this ensures that when water usage is high, the water flow in the cold water pipe reaches the preset ignition flow rate required to start the ignition system, thus ensuring the ignition system can start normally to meet the user's large water demand. On the other hand, it also minimizes the water flow in the cold water pipe at the beginning of water usage, causing more water stored in the second sub-space to flow to the outlet pipe, i.e., prioritizing the output of water stored in the second sub-space. Thus, when water usage is low, the water stored in the second sub-space is sufficient to meet the user's needs, eliminating the need to start the ignition system. This avoids frequent ignition system starts, reduces noise caused by frequent starts, prevents component fatigue failure, extends service life, and reduces the probability of safety accidents. Furthermore, if the water consumption at the water-using end is large, the water temperature output by the ignition system will need to stabilize to the set temperature after a period of time after startup. Before that, if more water stored in the second subspace with a temperature close to the set temperature is output first, the user's waiting time for water can be reduced, thus improving the user experience.

[0059] The above and other objects, advantages and features of the present invention will become more apparent to those skilled in the art from the following detailed description of specific embodiments of the invention in conjunction with the accompanying drawings. Attached Figure Description

[0060] The following sections will describe some specific embodiments of the invention in detail by way of example and not limitation, with reference to the accompanying drawings. The same reference numerals in the drawings denote the same or similar parts or portions. Those skilled in the art should understand that these drawings are not necessarily drawn to scale. In the drawings:

[0061] Figure 1 This is a schematic structural diagram of a gas water heater in a stopped water supply state according to an embodiment of the present invention;

[0062] Figure 2 This is a schematic structural diagram of a gas water heater in a state switching process according to an embodiment of the present invention;

[0063] Figure 3 This is a schematic structural diagram of a gas water heater in a continuous water output state according to an embodiment of the present invention;

[0064] Figure 4 This is a schematic flowchart of a control method for a gas water heater according to an embodiment of the present invention;

[0065] Figure 5This is a schematic flowchart of a control method for a gas water heater according to another embodiment of the present invention;

[0066] Figure 6 This is a schematic flowchart of a control method for a gas water heater according to yet another embodiment of the present invention;

[0067] Figure 7 This is a schematic structural diagram of a drive mechanism according to an embodiment of the present invention;

[0068] Figure 8 This is a schematic flowchart of a control method for a gas water heater according to another embodiment of the present invention;

[0069] Figure 9 This is a schematic flowchart of a control method for a gas water heater according to yet another embodiment of the present invention;

[0070] Figure 10 This is a schematic structural block diagram of a gas water heater according to an embodiment of the present invention. Detailed Implementation

[0071] This invention first provides a control method for a gas water heater, which is applicable to gas water heaters with special structures. Figure 1 This is a schematic structural diagram of a gas water heater in a stopped water supply state according to an embodiment of the present invention. Figure 2 This is a schematic structural diagram of a gas water heater in a state switching process according to an embodiment of the present invention. Figure 3 This is a schematic structural diagram of a gas water heater in a continuous water supply state according to an embodiment of the present invention. (See also...) Figures 1 to 3 The gas water heater 1 of the present invention includes a heat exchanger 10, a cold water pipe 21 connected to the upstream side of the heat exchanger 10, a hot water pipe 22 connected to the downstream side of the heat exchanger 10, an inlet pipe 23 for connecting to a tap water pipe, an outlet pipe 24 for connecting to a water outlet, a temperature sensor 71 for acquiring the water temperature in the inlet pipe 23, and an automatic thermostat 30. It is understood that the water outlet can specifically be a faucet, a shower head, etc.

[0072] Specifically, the automatic temperature control device 30 includes a tank 31, a baffle 32 disposed within the tank 31, and a drive mechanism 33. The baffle 32 divides the space within the tank 31 into a fluid-isolated first subspace 311 and a second subspace 312. That is, the first subspace 311 and the second subspace 312 are fluidly isolated by the baffle 32, and there is no fluid communication between them. The drive mechanism 33 is connected to the baffle 32, and the drive mechanism 33 is configured to controllably drive the baffle 32 to move along the arrangement direction of the first subspace 311 and the second subspace 312 to adjust the volume of the first subspace 311 and the second subspace 312. The baffle 32 can move along the first direction a and the second direction b in the figure under the action of the drive mechanism 33. The inlet pipe 23 is connected to the first subspace 311, and both the hot water pipe 22 and the outlet pipe 24 are connected to the second subspace 312. The cold water pipe 21 is configured to switch from being connected to the second subspace 312 to being connected to the first subspace 311 when water use is started at the water-using end, and to switch from being connected to the first subspace 311 to being connected to the second subspace 312 when water use is stopped at the water-using end. That is to say, when water use is started at the water-using end, the cold water pipe 21 is in the state of being connected to the second subspace 312. As the water use time increases, the distance that the baffle 32 moves along the first direction a gradually increases, the volume of the second subspace 312 becomes smaller and smaller, and the volume of the first subspace 311 becomes larger and larger, so the cold water pipe 21 can switch to the state of being connected to the first subspace 311. When water usage is stopped at the water-using end, the cold water pipe 21 is in a state of being connected to the first subspace 311. As the time of water usage cessation increases, the distance that the baffle 32 moves along the second direction b becomes larger and larger, the volume of the second subspace 312 becomes larger and larger, and the volume of the first subspace 311 becomes smaller and smaller. The cold water pipe 21 can then switch to a state of being connected to the second subspace 312.

[0073] Specifically, the tank 31 may have four connection ports that are respectively connected to the cold water pipe 21, the hot water pipe 22, the inlet pipe 23 and the outlet pipe 24, so as to allow the cold water pipe 21, the hot water pipe 22, the inlet pipe 23 and the outlet pipe 24 to connect to the first subspace 311 or the second subspace 312 inside the tank 31 through the corresponding connection ports.

[0074] The gas water heater 1 of the present invention divides the conventional cold water inlet pipe and hot water outlet pipe into two sections, forming four parts: cold water pipe 21, hot water pipe 22, inlet pipe 23, and outlet pipe 24. Furthermore, it is specially equipped with an automatic thermostatic device 30 comprising a tank 31, a baffle 32, a drive mechanism 33, and a temperature sensor. The baffle 32 divides the space within the tank 31 into a fluid-isolated first subspace 311 and a second subspace 312. The inlet pipe 23 is connected to the first subspace 311, while the hot water pipe 22 and the outlet pipe 24 are both connected to the second subspace 312. The cold water pipe 21 is selectively connected to either the first subspace 311 or the second subspace 312. Therefore, the hot water flowing out of the hot water pipe 22 first flows to the second subspace 312 to mix with the water stored in the second subspace 312 before flowing to the outlet pipe 24. Compared with the prior art, which mixes in the hot water outlet pipe, the present invention has a specially set mixing space (second subspace 312), which is larger. Therefore, the mixing speed is faster and the water mixing effect is better.

[0075] The control method of the present invention is designed based on a gas water heater 1 having at least the above-described structure. Figure 4 This is a schematic flowchart of a control method for a gas water heater according to an embodiment of the present invention. The control method of the present invention includes:

[0076] Step S10: Obtain the water temperature inside the inlet pipe 23; and

[0077] Step S20: Determine if the water temperature in the inlet pipe 23 is lower than the preset temperature value. If so, proceed to step S30; and

[0078] Step S30: Control the gas water heater 1 to enter the antifreeze mode.

[0079] In antifreeze mode, the control drive mechanism 33 drives the baffle 32 to move back and forth in the direction of the arrangement of the first subspace 311 and the second subspace 312 at a preset minimum speed. When the baffle 32 moves toward the second subspace 312, the water stored in the second subspace 312 flows through the hot water pipe 22, the heat exchanger 10, and the cold water pipe 21 in sequence before flowing into the first subspace 311. When the baffle 32 moves toward the first subspace 311, the water stored in the first subspace 311 flows through the cold water pipe 21, the heat exchanger 10, and the hot water pipe 22 in sequence before flowing into the second subspace 312.

[0080] The control method of this invention features a specially designed antifreeze mode when the water temperature in the inlet pipe 23 is low. In the antifreeze mode, the drive mechanism 33 drives the baffle 32 to reciprocate at a preset minimum speed in the arrangement direction of the first subspace 311 and the second subspace 312. When the baffle 32 moves toward the second subspace 312, it compresses the second subspace 312, causing the relatively warm water in the second subspace 312 to flow sequentially through the hot water pipe 22, the heat exchanger 10, and the cold water pipe 21 before flowing into the first subspace 311, where it neutralizes the cooler water in the first subspace 311 and the inlet pipe 23 connected to the first subspace 311. When the baffle 32 moves toward the first subspace 311, it compresses the first subspace 311, causing the water in the first subspace 311 to flow sequentially through the cold water pipe 21, the heat exchanger 10, and the hot water pipe 22 before flowing into the second subspace 312. After repeating this process multiple times, the existing higher-temperature water in the second subspace 312 can be used to raise the temperature of locations such as the hot water pipe 22, the heat exchanger 10, the cold water pipe 21, and the first subspace 312, which do not store hot water, thus preventing icing at these locations.

[0081] Specifically, the preset temperature value can be a positive value close to zero degrees Celsius, such as 1°C, 2°C, 3°C, etc. The water temperature in the inlet pipe 23 can be obtained by the temperature sensor 71 installed in the inlet pipe 23.

[0082] In some embodiments, if the water temperature in the inlet pipe 23 is lower than the preset temperature value, the control method of the present invention further includes:

[0083] A warning message is issued indicating that there is a risk of icing in gas water heater 1.

[0084] Since the water stored in the second subspace 312 is hot water saved from the last use at the water outlet, if no additional heating device is installed in the second subspace 312, the heat of the water in the second subspace 312 will gradually decrease, and the temperature will gradually drop, especially after the gas water heater 1 enters the anti-freeze mode, the water temperature in the second subspace 312 will drop even faster. If the water outlet is not used for a long time, the gas water heater 1 still has the risk of freezing. To this end, the present invention also issues a warning message indicating that the gas water heater 1 has the risk of freezing when the water temperature in the inlet pipe 23 is low, so that the user can drain the water in the gas water heater 1 when it is not used for a long time.

[0085] In some embodiments, a heating device 34 is provided within the second subspace 312. The heating device 34 may specifically be a heating rod, heating wire, heating plate, etc. See also these embodiments. Figure 5 The schematic flowchart shown is of a control method for a gas water heater according to another embodiment of the present invention. If the water temperature in the inlet pipe 23 is higher than the preset temperature value, the control method of the present invention further includes:

[0086] Step S41: Obtain the water temperature in the second subspace 312;

[0087] Step S42: Calculate the temperature difference between the set temperature of the gas water heater 1 and the water temperature in the second subspace 312;

[0088] Step S43: Determine whether the temperature difference is greater than the preset temperature difference value; if so, proceed to step S44.

[0089] Step S44: Start the heating device 34 to heat the water stored in the second subspace 312 until the water temperature in the second subspace 312 reaches the set temperature of the gas water heater 1.

[0090] In other words, when the gas water heater 1 is in non-antifreeze mode, the water temperature in the second sub-space 312 is continuously monitored. If the water temperature in the second sub-space 312 is low (for example, lower than the preset temperature difference value of the gas water heater 1), the heating device 34 is activated in time until the water temperature in the second sub-space 312 reaches the set temperature of the gas water heater 1. This ensures that the water temperature in the second sub-space 312 remains at a high level, so that users can directly obtain hot water at a suitable temperature when they turn on the unit for the first time or when they use water again after a long period of inactivity.

[0091] Specifically, the water temperature in the second subspace 312 can be obtained by a temperature sensor 72 located in the second subspace 312 or at the connection between the outlet pipe 24 and the second subspace 312.

[0092] In some embodiments, the gas water heater 1 further includes a solenoid valve 50 disposed within the cold water pipe 21 to adjust the flow area of ​​the cold water pipe 21. See also these embodiments. Figure 6 The schematic flowchart shown is a control method for a gas water heater according to another embodiment of the present invention. If the temperature difference between the set temperature of the gas water heater 1 and the water temperature in the second subspace 312 is less than or equal to the preset temperature difference value, the control method of the present invention further includes:

[0093] Step S51: Receive a water usage start signal, which indicates that the water user has started using water.

[0094] Step S52: Adjust the opening degree of solenoid valve 50 to the preset minimum opening degree; wherein

[0095] The preset minimum opening is set so that the water flow in the cold water pipe 21 is just enough to trigger the preset ignition flow to start the ignition system of the gas water heater 1.

[0096] If the temperature difference is less than or equal to the preset temperature difference value, it indicates that the water temperature in the second subspace 312 is close to the set temperature of the gas water heater 1, and the water stored in the second subspace 312 can basically meet the user's water temperature requirements. Therefore, at this time, the present invention adjusts the opening of the solenoid valve 50 to the preset minimum opening. On the one hand, when the water consumption at the water end is large, it can ensure that the water flow in the cold water pipe 21 can reach the preset ignition flow to start the ignition system, thereby ensuring that the ignition system can start normally to meet the user's large water demand. On the other hand, it also minimizes the water flow in the cold water pipe 21 as much as possible when the water consumption at the water end just begins to flow, causing more of the water stored in the second subspace 312 to flow to the outlet pipe 24, that is, to prioritize the output of the water stored in the second subspace 312. In this way, when the water consumption at the water end is small, the water stored in the second subspace 312 can meet the user's needs. At this time, there is no need to start the ignition system, avoiding frequent starting of the ignition system, reducing the noise caused by frequent starting of the ignition system, avoiding fatigue failure of components, thereby extending the service life and reducing the probability of safety accidents.

[0097] Furthermore, if the water consumption at the water-using end is large, the water temperature output by the ignition system will need to stabilize to the set temperature after a period of time after startup. Before that, if more water stored in the second subspace with a temperature close to the set temperature is output first, the user's waiting time for water can be reduced, thus improving the user experience.

[0098] It should be noted that the ignition system of the present invention has a broad meaning that includes a gas valve, and is used to control the ignition and extinguishing of a gas water heater. The start of the ignition system means controlling the gas water heater to ignite, and the stop of the ignition system means controlling the gas water heater to extinguish.

[0099] Figure 7 This is a schematic structural diagram of a drive mechanism according to an embodiment of the present invention. In some embodiments, the drive mechanism 33 includes a motor 331 located outside the tank body 31, a helical rod 332 connected to the motor 331 and extending into the tank body 31, and a telescopic rod 333 that selectively retracts into or extends from the helical rod 332, the end of the telescopic rod 333 being connected to a baffle 32. Specifically, one end of the telescopic rod 333 can be sleeved with the helical rod 332 via a spring 334, so that it selectively retracts into or extends from the helical rod 332 as the spring 334 extends or retracts. In these embodiments, see [link to relevant documentation]. Figure 8 The schematic flowchart shown here illustrates a control method for a gas water heater according to another embodiment of the present invention. After adjusting the opening degree of the solenoid valve 50 to a preset minimum opening degree, the control method of the present invention further includes:

[0100] Step S61: Receive an ignition start signal, which is generated when the water flow rate in the cold water pipe 21 reaches the preset ignition flow rate;

[0101] Step S62: Start the ignition system and control the motor 331 to rotate in the forward direction;

[0102] Step S63: Obtain the water flow rate in the outlet pipe 24;

[0103] Step S64: Adjust the opening of the solenoid valve 50 according to the water flow rate in the outlet pipe 24 until the opening of the solenoid valve 50 reaches the preset maximum opening; and

[0104] In step S65, the speed of motor 331 is adjusted according to the water flow rate in water outlet pipe 24 and the opening degree of solenoid valve 50, so as to adjust the moving speed of baffle 32 until baffle 32 moves to the preset position.

[0105] Specifically, when the water supply is continuously stopped at the water-using end, the inlet pressure at the inlet pipe 23 is the same as the outlet pressure at the outlet pipe 24. The forces on both sides of the baffle 32 are balanced and maintained at the first position A. The motor 31 is in a stopped state. Therefore, the spring connecting the telescopic rod 333 and the screw rod 332 is in a natural state, and the telescopic rod 333 is retracted into the screw rod 332. At this time, the larger second subspace 312 stores the hot water that flowed from the heat exchanger 10 after the last water use at the water-using end.

[0106] After the user starts using water, and before the ignition system starts, the pressure at the outlet pipe 24 drops sharply. The inlet pressure at the inlet pipe 23 is greater than the outlet pressure at the outlet pipe 24. Water flows into the first subspace 311 through the inlet pipe 23, squeezing the baffle 32. This causes the baffle 32 to move together with the telescopic rod 333 from the first position A towards the first direction a, pushing the hot water in the second subspace 312 towards the outlet pipe 24 so that the user can obtain hot water in time. During this process, the spring 33 undergoes elastic deformation. Since the cold water pipe 21 is connected to the second subspace 312 at this time, the water volume in the second subspace 312 is limited, and most of the water flows to the outlet pipe 24. Therefore, the water flow to the cold water pipe 21 is very small. At this time, the ignition system will not start, and the motor 331 will not rotate.

[0107] As the baffle 32 moves further in the first direction a, the cold water pipe 21 switches to a position just connected to the first subspace 311 (i.e., the baffle 32 is in the second position B). At this point, the flow rate in the cold water pipe 21 reaches the preset ignition flow rate, the ignition system starts, the motor 331 rotates forward, driving the screw rod 332 to move in the first direction a. The screw rod 332 pushes the baffle 32 to continue moving in the first direction a until the baffle 32 moves to the third position C (i.e., the aforementioned preset position). At this point, the motor 331 stops rotating forward, the baffle 31 stops moving and remains in the third position C. After the cold water pipe 21 switches to a position connected to the first subspace 311, most of the water flowing in through the inlet pipe 23 flows into the cold water pipe 21, while a small portion remains in the first subspace 311. When the baffle 31 stops moving, the water flow rate flowing in through the inlet pipe 23 is the same as the water flow rate flowing into the cold water pipe 21 through the first subspace 311. The heat exchanger 10 continuously generates hot water, which flows into the second subspace 312 through the hot water pipe 22, and then flows from the second subspace 312 to the outlet pipe 24.

[0108] After the ignition system is started, the opening degree of the solenoid valve 50 is not constant, but a variable related to the water flow rate in the outlet pipe 24. After the motor 331 starts to rotate in the forward direction, the speed of the motor 331 is also not constant, but a variable related to both the water flow rate in the outlet pipe 24 and the opening degree of the solenoid valve 50.

[0109] Specifically, the water flow rate in the outlet pipe 24 can be measured by the flow sensor 42 installed in the outlet pipe 24.

[0110] In some embodiments, the step of adjusting the opening degree of the solenoid valve 50 according to the water flow rate of the outlet pipe 24 may specifically include:

[0111] The opening degree of solenoid valve 50 is calculated using the following formula:

[0112] y t = k×t + y0; where

[0113] y t This indicates the opening degree of solenoid valve 50 at time t after receiving the ignition start signal, where t represents the water usage time since receiving the ignition start signal, y0 represents the preset minimum opening degree, and k represents a coefficient proportional to the user's water flow rate. In other words, multiple different k values ​​can be preset; the greater the user's water flow rate (e.g., the larger the faucet opening), the larger the value of k.

[0114] Based on the above-mentioned determination of the opening degree of the solenoid valve 50, the present invention can gradually increase the opening degree of the solenoid valve 50 from the preset minimum opening degree after receiving the ignition start signal, so as to ensure that enough water is heated by the heat exchanger 10 and replenished into the second subspace 312 to meet the user's water consumption needs.

[0115] In some embodiments, the step of adjusting the rotational speed of the motor 331 according to the water flow rate in the outlet pipe 24 and the opening degree of the solenoid valve 50 to adjust the moving speed of the baffle 32 may specifically include:

[0116] Calculate the water flow rate in the cold water pipe 21 based on the opening degree of the solenoid valve 50;

[0117] Calculate the flow rate difference between the water flow rate in water pipe 24 and the water flow rate in cold water pipe 21;

[0118] Calculate the target moving speed of baffle 32 using the following formula:

[0119] Q0 = (Q1 - Q2) / S; where Q0 represents the flow difference, Q1 represents the water flow rate in the outlet pipe 24, Q2 represents the water flow rate in the cold water pipe 21, and S represents the cross-sectional area of ​​the tank.

[0120] Calculate the target rotational speed of motor 331 based on the target moving speed of baffle 32; and

[0121] Control motor 331 to run at the target speed.

[0122] The present invention controls the speed of motor 331 according to the water flow rate in outlet pipe 24 and the water flow rate in cold water pipe 21, which not only meets the different water consumption needs of users, but also controls the water flow rate in cold water pipe 21 in a targeted manner, thereby controlling the ratio between the water consumption in the second subspace 312 and the hot water consumption after heat exchange by heat exchanger 10.

[0123] Figure 9 This is a schematic flowchart of a control method for a gas water heater according to yet another embodiment of the present invention. In some embodiments, after the opening degree of the solenoid valve 50 reaches a preset maximum opening degree, the control method of the present invention further includes:

[0124] Step S71: Receive a water usage stop signal, which indicates that the water user has stopped using the water.

[0125] Step S72: Adjust the opening of the solenoid valve 50 to the preset initial opening, and control the motor 331 to rotate in the reverse direction; wherein

[0126] The initial opening is set to be greater than zero and less than the minimum opening.

[0127] In other words, when the water supply stops, fluid is allowed to continue flowing through the cold water pipe 21, but the maximum allowable flow rate is less than the preset ignition flow rate. This is because when a water supply stop signal is received, the motor 331 starts to rotate in the reverse direction, driving the screw rod 332 to move the baffle 32 in the second direction b. The baffle 32 pushes the water in the first subspace 311 from the cold water pipe 21 into the heat exchanger 10, and after flowing through the heat exchanger 10, it enters the second subspace 312. During this process, by controlling the opening of the solenoid valve 50, the water flow rate in the cold water pipe 21 can be prevented from reaching the preset ignition flow rate, thus preventing the ignition system from restarting.

[0128] Furthermore, the motor 331 automatically stops rotating in the reverse direction after rotating a preset angle. This preset angle is the angle that the motor 331 rotates from starting to rotating in the forward direction until it stops rotating in the forward direction. That is, the motor 331 stops rotating in the reverse direction when it returns to its original state.

[0129] Furthermore, after receiving the water usage stop signal, the control method of the present invention further includes:

[0130] Receives an ignition stop signal; the ignition stop signal is generated when the water flow rate in the cold water pipe 21 is less than the preset ignition flow rate; and

[0131] Stop the ignition system.

[0132] As mentioned earlier, when water usage stops at the water-using end, the opening degree of the solenoid valve 50 is greater than zero and less than the preset minimum opening degree. At this time, the water flow rate in the cold water pipe 21 will inevitably be less than the preset ignition flow rate. Therefore, the ignition system stops when water usage stops at the water-using end to control flameout. Specifically, the water flow rate in the cold water pipe 21 can be obtained by the flow sensor 41 installed in the cold water pipe 21.

[0133] When the motor 331 stops reversing, the spring 334 begins to recover its deformation. Under the action of the elastic deformation recovery force of the spring 334, the baffle 32 continues to move in the second direction b. A small amount of water in the second subspace 312 flows to the heat exchanger 10 through the cold water pipe 21, absorbs a small amount of residual heat from the heat exchanger 10, and then flows into the second subspace 312 through the hot water pipe 22 until the spring 334 has completely recovered its deformation. Then the baffle 32 stops moving and returns to the first position A. At this time, the second subspace 312 stores a large amount of warm water at a suitable temperature for the user to use next time.

[0134] In some embodiments, the preset ignition flow rate is set to be greater than the maximum water flow rate in the cold water pipe 21 when it is connected to the second subspace 312, and equal to or less than the minimum water flow rate in the cold water pipe 21 when it is connected to the first subspace 311. That is, when the cold water pipe 21 is connected to the second subspace 312, the ignition system will not start; when the cold water pipe 21 is switched to a state where it is just fully connected to the first subspace 311 (e.g., ...), the ignition system will not start. Figure 2 When water flows into the inlet pipe 23 (position B in the second subspace), the ignition system will start immediately. This ensures that when the water consumption at the water end is low, the pre-stored warm water in the second subspace 312 is used to meet the user's water needs without having to start the ignition system, thus avoiding frequent starts of the ignition system; and it also ensures that the ignition system can start stably when the water consumption at the water end is high, so as to meet the user's higher water consumption needs.

[0135] The present invention also provides a gas water heater, see below. Figures 1 to 3 The gas water heater 1 of the present invention includes a heat exchanger 10, a cold water pipe 21 connected to the upstream side of the heat exchanger 10, a hot water pipe 22 connected to the downstream side of the heat exchanger 10, an inlet pipe 23 for connecting to a tap water pipe, an outlet pipe 24 for connecting to a water user, a temperature sensor 71 for acquiring the water temperature in the inlet pipe 23, and an automatic thermostat 30. The automatic thermostat 30 includes a tank 31, a drive mechanism 33, and a baffle 32 disposed within the tank 31.

[0136] Baffle 32 divides the space inside tank 31 into a fluid-isolated first subspace 311 and a second subspace 312. Drive mechanism 33 is connected to baffle 32 and is configured to controllably drive baffle 32 to move along the arrangement direction of the first subspace 311 and the second subspace 312 to adjust the volume of the first subspace 311 and the second subspace 312. Inlet pipe 23 is connected to the first subspace 311, hot water pipe 22 and outlet pipe 24 are both connected to the second subspace 312, and cold water pipe 21 is configured to switch from being connected to the second subspace 312 to being connected to the first subspace 311 when water is started at the water-using end, and to switch from being connected to the first subspace 311 to being connected to the second subspace 312 when water is stopped at the water-using end.

[0137] In particular, Figure 10 This is a schematic structural block diagram of a gas water heater according to an embodiment of the present invention. The gas water heater 1 also includes a control device 60 electrically connected to a temperature sensor 71 and a drive mechanism 33. The control device 60 includes a processor 61 and a memory 62. The memory 62 stores a machine-executable program 63, and when the machine-executable program 63 is executed by the processor 61, it is used to implement the control method described in any of the above embodiments.

[0138] In some embodiments, the automatic thermostat 30 further includes an insulation layer (not shown in the figure) that covers the outside of the tank 31, thereby preventing heat loss from the water stored in the second subspace 312, so that hot water can still be obtained in a timely manner when the water is turned on again after a long period of inactivity.

[0139] Those skilled in the art should understand that the embodiments described above are merely some embodiments of the present invention, and not all embodiments of the present invention. These embodiments are intended to explain the technical principles of the present invention and are not intended to limit the scope of protection of the present invention. Based on the embodiments provided by the present invention, all other embodiments obtained by those skilled in the art without creative effort should still fall within the scope of protection of the present invention.

[0140] It should be noted that in the description of this invention, terms such as "center," "upper," "lower," "top," "bottom," "left," "right," "vertical," "horizontal," "inner," and "outer," which indicate direction or positional relationships, are based on the direction or positional relationships shown in the accompanying drawings. These are used merely for ease of description and do not indicate or imply that the device or element must have a specific orientation, or be constructed and operated in a specific orientation; therefore, they should not be construed as limitations on this invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0141] Furthermore, it should be noted that, in the description of this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; 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; and they can also refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0142] Furthermore, it should be noted that in the description of this invention, each functional module can be a physical module composed of multiple structures, components, or electronic devices, or a virtual module composed of multiple programs; each functional module can be an independent module or a module divided from a whole module according to its function. Those skilled in the art should understand that, provided the technical solution described in this invention can be implemented, any changes in the configuration, implementation, or positional relationship of the functional modules will not deviate from the technical principles of this invention, and therefore should all fall within the protection scope of this invention.

[0143] Therefore, those skilled in the art should recognize that although numerous exemplary embodiments of the present invention have been shown and described in detail herein, many other variations or modifications conforming to the principles of the present invention can be directly determined or derived from the disclosure of the present invention without departing from the spirit and scope of the invention. Thus, the scope of the present invention should be understood and construed as covering all such other variations or modifications.

Claims

1. A control method for a gas water heater, the gas water heater comprising a heat exchanger, a cold water pipe connected to the upstream side of the heat exchanger, a hot water pipe connected to the downstream side of the heat exchanger, an inlet pipe for connecting to a tap water pipe, an outlet pipe for connecting to a water user, a temperature sensor for acquiring the water temperature in the inlet pipe, and an automatic thermostat, the automatic thermostat comprising a tank, a drive mechanism, and a baffle disposed in the tank; The baffle divides the space inside the tank into a fluid-isolated first subspace and a second subspace; the drive mechanism is connected to the baffle and is configured to controllably drive the baffle to move along the arrangement direction of the first subspace and the second subspace to adjust the volume of the first subspace and the second subspace; in The inlet pipe is connected to the first subspace, and the hot water pipe and the outlet pipe are both connected to the second subspace. The cold water pipe is configured to switch from being connected to the second subspace to being connected to the first subspace when water is started at the water-using end, and to switch from being connected to the first subspace to being connected to the second subspace when water is stopped at the water-using end. When water is started at the water-using end, the cold water pipe is connected to the second subspace. As the water usage time increases, the distance the baffle moves along the first direction a gradually increases, the volume of the second subspace becomes smaller and smaller, the volume of the first subspace becomes larger and larger, and the cold water pipe switches to being connected to the first subspace. When water is stopped at the water-using end, the cold water pipe is connected to the first subspace. As the water usage time decreases, the distance the baffle moves along the second direction b increases, the volume of the second subspace becomes larger and larger, the volume of the first subspace becomes smaller and smaller, and the cold water pipe switches to being connected to the second subspace. and The control method includes: Obtain the water temperature inside the inlet pipe; and If the water temperature in the inlet pipe is lower than the preset temperature value, the gas water heater is controlled to enter the anti-freeze mode; wherein In the antifreeze mode, the drive mechanism is controlled to move the baffle back and forth in the arrangement direction of the first subspace and the second subspace at a preset minimum speed. When the baffle moves toward the second subspace, the water in the second subspace flows sequentially through the hot water pipe, the heat exchanger, and the cold water pipe before flowing into the first subspace. When the baffle moves toward the first subspace, the water in the first subspace flows sequentially through the cold water pipe, the heat exchanger, and the hot water pipe before flowing into the second subspace.

2. The control method according to claim 1, wherein... If the water temperature in the inlet pipe is lower than the preset temperature value, the control method further includes: A warning message is issued indicating that the gas water heater is at risk of freezing.

3. The control method according to claim 1, wherein, A heating device is provided in the second subspace; and If the water temperature in the inlet pipe is higher than the preset temperature value, the control method further includes: Obtain the water temperature in the second subspace; Calculate the temperature difference between the set temperature of the gas water heater and the water temperature; If the temperature difference is greater than the preset temperature difference value, the heating device is activated to heat the water in the second subspace until the water temperature in the second subspace reaches the set temperature.

4. The control method according to claim 3, wherein, The gas water heater also includes a solenoid valve disposed inside the cold water pipe to adjust the flow area of ​​the cold water pipe. and If the temperature difference is less than or equal to the preset temperature difference value, the control method further includes: Receive a water usage start signal, the water usage start signal being used to indicate that the water user has started water usage; Adjust the opening degree of the solenoid valve to a preset minimum opening degree; wherein The preset minimum opening is set so that the water flow in the cold water pipe is just enough to trigger the ignition system of the gas water heater to start.

5. The control method according to claim 4, wherein, The drive mechanism includes a motor located outside the tank, a helical rod connected to the motor and extending into the tank, and a telescopic rod that selectively retracts into or extends from the helical rod, the end of which is connected to the baffle. and After adjusting the opening of the solenoid valve to a preset minimum opening, the control method further includes: Receive an ignition start signal, which is generated when the water flow rate in the cold water pipe reaches the preset ignition flow rate; Start the ignition system and control the motor to rotate in the forward direction; Obtain the water flow rate in the outlet pipe; Adjust the opening of the solenoid valve according to the water flow rate in the outlet pipe until the opening of the solenoid valve reaches the preset maximum opening; and The speed of the motor is adjusted according to the water flow rate in the outlet pipe and the opening degree of the solenoid valve, so as to adjust the speed of the baffle movement until the baffle moves to the preset position.

6. The control method according to claim 5, wherein The steps for adjusting the opening degree of the solenoid valve according to the water flow rate of the outlet pipe include: The opening degree of the solenoid valve is calculated using the following formula: y t =k×t+y0; where y t The value represents the opening degree of the solenoid valve at time t after receiving the ignition start signal, where t represents the water usage time since receiving the ignition start signal, y0 represents the preset minimum opening degree, and k represents a coefficient proportional to the user's water consumption.

7. The control method according to claim 5, wherein The step of adjusting the motor speed according to the water flow rate in the outlet pipe and the opening degree of the solenoid valve to adjust the speed of the baffle movement includes: The water flow rate in the cold water pipe is calculated based on the opening degree of the solenoid valve; Calculate the flow rate difference between the water flow rate in the outlet pipe and the water flow rate in the cold water pipe; The target moving speed of the baffle is calculated using the following formula: Q0 = (Q1 - Q2) / S; where Q0 represents the flow difference, Q1 represents the water flow rate in the outlet pipe, Q2 represents the water flow rate in the cold water pipe, and S represents the cross-sectional area of ​​the tank. The target rotational speed of the motor is calculated based on the target moving speed of the baffle. as well as Control the motor to run at the target speed.

8. The control method according to claim 5, wherein After the solenoid valve reaches the preset maximum opening degree, the control method further includes: Receive a water usage stop signal, the water usage stop signal being used to indicate that the water-using end has stopped using water; and Adjust the opening of the solenoid valve to a preset initial opening, and control the motor to rotate in the reverse direction; in The preset initial opening degree is greater than zero and less than the preset minimum opening degree.

9. The control method according to claim 8, wherein After receiving the water usage stop signal, the control method further includes: Receive an ignition stop signal, which is generated when the water flow rate in the cold water pipe is less than the preset ignition flow rate; as well as Stop the ignition system.

10. The control method according to claim 4, wherein The preset ignition flow rate is set to be greater than the maximum water flow rate in the cold water pipe when the cold water pipe is connected to the second subspace, and equal to or less than the minimum water flow rate in the cold water pipe when the cold water pipe is connected to the first subspace.

11. A gas water heater, comprising a heat exchanger, a cold water pipe connected to the upstream side of the heat exchanger, a hot water pipe connected to the downstream side of the heat exchanger, an inlet pipe for connecting to a tap water pipe, an outlet pipe for connecting to a water user, and an automatic thermostat, the automatic thermostat comprising a tank, a baffle and a temperature sensor disposed in the tank, and a drive mechanism. The baffle divides the space inside the tank into a fluid-isolated first subspace and a second subspace; the drive mechanism is connected to the baffle and is configured to controllably drive the baffle to move along the arrangement direction of the first subspace and the second subspace to adjust the volume of the first subspace and the second subspace; The inlet pipe is connected to the first subspace, the hot water pipe and the outlet pipe are both connected to the second subspace, and the cold water pipe is configured to switch from being connected to the second subspace to being connected to the first subspace when water is used at the water-using end, and to switch from being connected to the first subspace to being connected to the second subspace when water is used at the water-using end; and The gas water heater further includes a control device, which includes a processor and a memory. The memory stores a machine-executable program, and when executed by the processor, the machine-executable program is used to implement the control method according to any one of claims 1-10.

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