Defrosting device for refrigerator and control method

Abstract

The invention provides a defrosting device for a refrigerator and a control method. The defrosting device comprises a compressor, a condenser, a filter, an electric valve, a first heating wire device, a second heating wire device, a freezing capillary tube, a freezing evaporator and a bypass pipe. An inlet of the condenser is connected with an outlet of the compressor, and an outlet of the condenser is connected with an inlet of the filter; the electrically operated valve is provided with an inlet and at least two outlets, and the inlet of the electrically operated valve is connected with the outlet of the filter; a first outlet of the electric valve is connected with an inlet of the freezing evaporator through a bypass pipe, and a second outlet of the electric valve is connected with the inlet of the freezing evaporator through a freezing capillary pipe; the first heating wire device is arranged on the outer wall of the bypass pipe, and the second heating wire device is arranged on the outer wall of an air return pipeline of the compressor; and an outlet of the freezing evaporator is connected with the air return pipeline and leads to an inlet of the compressor, so that the problems of low defrosting efficiency and high energy consumption of the refrigerator are solved.

Description

Technical Field

[0001] This application relates to the field of refrigerator technology, and in particular to a defrosting device and control method for a refrigerator. Background Technology

[0002] During operation, the surface temperature of the evaporator in a frost-free refrigerator is typically much lower than the dew point temperature of the air inside the refrigerator. Water vapor in the air condenses on the evaporator surface, gradually forming a solid frost layer. This frost buildup hinders airflow and heat exchange, leading to decreased cooling efficiency, increased energy consumption, and potentially affecting the stability of the equipment. Therefore, an efficient and reliable defrosting method is needed to remove frost from the evaporator surface and ensure the refrigerator's continued efficient operation under various conditions.

[0003] Common refrigerator defrosting methods mainly include electric defrosting and hot gas defrosting. Electric defrosting involves placing an electric heating element near the evaporator, which generates heat to melt the frost layer. Hot gas defrosting, on the other hand, utilizes the high-temperature, high-pressure refrigerant generated by the compressor, which is bypassed to the evaporator, using the heat of the refrigerant to defrost the refrigerator.

[0004] However, the above methods each have their limitations. Electric defrosting is relatively inefficient and energy-intensive, and the heat it generates can cause significant fluctuations in the refrigerator's internal temperature, negatively impacting food preservation. Traditional hot-gas defrosting relies entirely on the compressor's operation, which limits the heat source supply. Especially at low ambient temperatures, the heat supply further decreases, resulting in slow defrosting, incomplete defrosting, and the risk of residual frost or even secondary frost formation due to refrigerant absorbing heat during secondary evaporation in the evaporator. Furthermore, in the initial stages of defrosting, a large amount of liquid refrigerant may flow back to the compressor, increasing the risk of liquid slugging. Summary of the Invention

[0005] This application provides a defrosting device and control method for refrigerators, which can effectively solve the problems of low defrosting efficiency and high energy consumption in refrigerators.

[0006] The first aspect of this application provides a defrosting device for a refrigerator, comprising: a compressor, a condenser, a filter, an electric valve, a first heating wire device, a second heating wire device, a freezing capillary tube, a freezing evaporator, and a bypass pipe; The inlet of the condenser is connected to the outlet of the compressor, and the outlet of the condenser is connected to the inlet of the filter; The electric valve has one inlet and at least two outlets, and the inlet of the electric valve is connected to the outlet of the filter; The first outlet of the electric valve is connected to the inlet of the refrigeration evaporator through the bypass pipe, and the second outlet of the electric valve is connected to the inlet of the refrigeration evaporator through the refrigeration capillary tube; The first heating wire device is disposed on the outer wall of the bypass pipe, and the second heating wire device is disposed on the outer wall of the return gas pipeline of the compressor; The outlet of the refrigeration evaporator is connected to the return gas pipeline and leads to the inlet of the compressor.

[0007] By installing a first heating wire device on the outer wall of the bypass pipe and a second heating wire device on the outer wall of the compressor's return gas line, the high-temperature refrigerant generated by the compressor during the defrosting process can enter the refrigeration evaporator through the bypass pipe for hot gas defrosting. At the same time, the heating wire device increases the temperature of the medium in the pipeline, which helps to improve defrosting efficiency. The second heating wire device heats the refrigerant in the return gas line, which helps to increase the compressor's suction temperature, thereby mitigating the risk of liquid slugging in the compressor.

[0008] Optional features also include a refrigeration capillary tube, a refrigeration evaporator, and a one-way valve; The electric valve is a one-inlet, three-outlet valve, and also includes a third outlet; The third outlet is connected to the inlet of the refrigeration evaporator via the refrigeration capillary tube, and the outlet of the refrigeration evaporator is connected to the inlet of the freezer evaporator via the one-way valve; The electric valve has four operating states: defrosting state with the first outlet connected, freezing state with the second outlet connected, refrigeration state with the third outlet connected, and shut-off state with all outlets disconnected.

[0009] By incorporating a third outlet into a three-way valve, the electric valve achieves a refrigeration state with the third outlet connected. In this state, refrigerant flowing from the third outlet passes through the refrigeration capillary tube and the refrigeration evaporator, then through a one-way valve into the freezing evaporator, thus enabling the freezer compartment to refrigerate while the refrigerator compartment refrigerates. Simultaneously, in a shut-off state where all outlets of the electric valve are disconnected, the high-temperature, high-pressure refrigerant is contained within the condenser piping, maintaining pressure. Furthermore, the one-way valve controls the refrigerant to flow only in a preset direction, helping to prevent high-temperature refrigerant generated by the compressor from entering the refrigeration evaporator during defrosting, thereby mitigating the rise in refrigerator compartment temperature.

[0010] Optionally, both the first heating wire device and the second heating wire device are spiral-wound heating wires; The spiral-wound heating wire is continuously spirally wound along the axial direction of the bypass pipe or the return gas pipe, and is tightly attached to the outer wall of the bypass pipe or the return gas pipe.

[0011] The first heating wire device and the second heating wire device adopt a spiral wound heating wire, which is continuously spirally wound along the axial direction of the attached refrigerant pipeline and closely adheres to the outer wall of the pipeline. This helps to achieve efficient heat conduction between the heating wire device and the pipeline, thereby increasing the temperature of the medium inside the pipeline.

[0012] Optionally, the bypass pipe is pre-embedded inside the foamed insulation layer of the refrigerator body.

[0013] The bypass pipe is embedded inside the foamed insulation layer of the refrigerator body, which helps to reduce heat loss when the high-temperature refrigerant flows in the bypass pipe during defrosting, thereby improving the heat utilization efficiency of hot gas defrosting.

[0014] Optionally, the first heating wire device and the second heating wire device are integrated on the same flexible insulating substrate; the flexible insulating substrate also covers the outer wall of the bypass pipe and the return gas pipe of the compressor.

[0015] The first heating wire device and the second heating wire device are integrated on the same flexible insulating substrate. This substrate covers the outer wall of both the bypass pipe and the compressor's return gas pipe, which helps to achieve the synchronous installation and fixation of the two heating wire devices through a single substrate, thereby improving the structural integration and assembly efficiency of the defrosting device.

[0016] A second aspect of this application provides a defrosting device control method for a refrigerator, applied to the defrosting device for a refrigerator described in the first aspect, the method comprising: When the defrosting start conditions are met, the electric control valve is connected to the first outlet to activate the defrosting branch. Control the compressor to run at the first speed to draw refrigerant from the refrigeration evaporator; Obtain the compressor's return gas temperature and environmental parameters, and calculate the dew point temperature based on the environmental parameters; When the return gas temperature is lower than the dew point temperature, the first heating wire device is activated; When the return gas temperature is higher than or equal to the dew point temperature, the compressor is controlled to switch to a second speed lower than the first speed to provide defrosting heat to the refrigeration evaporator; Obtain the temperature at the inlet of the refrigeration evaporator; When the temperature at the inlet of the refrigeration evaporator is lower than the dew point temperature, the second heating wire device is activated. When the temperature at the inlet of the refrigeration evaporator is higher than or equal to the dew point temperature, the cumulative running time of the compressor during the defrosting stage and the temperature of the refrigeration evaporator are continuously monitored. When the cumulative running time reaches the first time threshold, or the temperature of the evaporator reaches the preset temperature threshold, defrosting is determined to be complete, and the electric valve is controlled to switch to the off state.

[0017] By controlling the compressor to run at its first speed during defrosting startup, it helps to extract the low-temperature refrigerant remaining in the evaporator, thereby reducing the heat loss during defrosting caused by the refrigerant's secondary evaporation and heat absorption in the evaporator. By activating the first heating element based on the comparison between the return gas temperature and the dew point temperature, and the second heating element based on the comparison between the evaporator inlet temperature and a preset threshold, the heating elements are activated in stages according to the compressor return gas temperature and the evaporator inlet temperature, which helps to regulate the heat supply during the defrosting process. By detecting the cumulative running time of the compressor and the temperature of the evaporator and determining that defrosting is complete when the conditions are met, the criteria for judging the defrosting duration and defrosting endpoint are more comprehensive, which helps to balance the energy consumption and defrosting effect during the defrosting process.

[0018] Optionally, in the step of controlling the compressor to run at a first speed, if the condenser is an air-cooled condenser, the fan of the condenser is simultaneously controlled to shut down.

[0019] During the process of controlling the compressor to run at the first speed, if the condenser is an air-cooled condenser, the synchronous control of shutting down the condenser fan helps to reduce the heat loss generated by the compressor in the condenser, thereby improving the heat supply efficiency of the defrosting branch.

[0020] Optionally, the step of controlling the compressor to operate at a first speed includes: controlling the compressor to operate at a speed of 2100 rpm to 3000 rpm; The step of controlling the compressor to switch to the second speed includes: controlling the compressor to run at a speed of 1200 rpm to 1500 rpm.

[0021] By controlling the compressor to operate at a first speed of 2100 to 3000 rpm, it helps to quickly extract refrigerant from the evaporator during the initial defrosting stage; by controlling the compressor to switch to a second speed of 1200 to 1500 rpm, it helps to continuously supply defrosting heat to the evaporator.

[0022] Optionally, the method further includes: when the cumulative running time has not reached the first time threshold and the temperature of the refrigeration evaporator has not reached the preset temperature threshold, continuing to control the compressor to switch to the second speed.

[0023] If the cumulative running time has not reached the first time threshold and the temperature of the evaporator has not reached the preset temperature threshold, the compressor continues to run at the second speed, which helps to maintain a continuous supply of defrosting heat to the evaporator, thereby improving the integrity of the defrosting process.

[0024] Optionally, in the conditions for determining that defrosting is complete, the first time threshold is 20 to 30 minutes, and the preset temperature threshold is 5 to 10 degrees Celsius.

[0025] In determining the completion of defrosting, the first time threshold is set to 20 to 30 minutes, and the preset temperature threshold is set to 5 to 10 degrees Celsius, providing specific execution basis for controlling the defrosting time and determining the defrosting endpoint.

[0026] As can be seen from the above technical solutions, this application provides a defrosting device and control method for a refrigerator. The defrosting device includes: a compressor, a condenser, a filter, an electric valve, a first heating wire device, a second heating wire device, a freezing capillary tube, a freezing evaporator, and a bypass pipe; the inlet of the condenser is connected to the outlet of the compressor, and the outlet of the condenser is connected to the inlet of the filter; the electric valve has one inlet and at least two outlets, and the inlet of the electric valve is connected to the outlet of the filter; the first outlet of the electric valve is connected to the inlet of the freezing evaporator through the bypass pipe, and the second outlet of the electric valve is connected to the inlet of the freezing evaporator through the freezing capillary tube; the first heating wire device is disposed on the outer wall of the bypass pipe, and the second heating wire device is disposed on the outer wall of the compressor's return gas pipeline; the outlet of the freezing evaporator is connected to the return gas pipeline and leads to the inlet of the compressor, thereby solving the problems of low defrosting efficiency and high energy consumption in refrigerators. Attached Figure Description

[0027] To more clearly illustrate the technical solution of this application, the drawings used in the embodiments will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 This is a schematic diagram of a first structure of a defrosting device for a refrigerator in an embodiment of this application; Figure 2 This is a schematic diagram of a second structure of a defrosting device for a refrigerator in an embodiment of this application; Figure 3 This is a flowchart illustrating the defrosting device control method for a refrigerator in an embodiment of this application.

[0029] Among them, 1-compressor; 2-condenser; 3-filter; 4-electric valve; 41-first outlet; 42-second outlet; 43-third outlet; 5-first heating wire device; 6-second heating wire device; 7-freezing capillary; 8-refrigeration capillary; 9-refrigeration evaporator; 10-one-way valve; 11-freezing evaporator; 12-bypass pipe. Detailed Implementation

[0030] The embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described below do not represent all embodiments consistent with this application. They are merely examples of systems and methods consistent with some aspects of this application as detailed in the claims.

[0031] To address the issues of low defrosting efficiency and high energy consumption in refrigerators, see [link / reference]. Figures 1-2 This application provides a defrosting device for a refrigerator, comprising: a compressor 1, a condenser 2, a filter 3, an electric valve 4, a first heating wire device 5, a second heating wire device 6, a freezing capillary tube 7, a freezing evaporator 11, and a bypass pipe 12; the inlet of the condenser 2 is connected to the outlet of the compressor 1, and the outlet of the condenser 2 is connected to the inlet of the filter 3.

[0032] The electric valve 4 has one inlet and at least two outlets. The inlet of the electric valve 4 is connected to the outlet of the filter 3. The first outlet 41 of the electric valve 4 is connected to the inlet of the refrigeration evaporator 11 through the bypass pipe 12, and the second outlet 42 of the electric valve 4 is connected to the inlet of the refrigeration evaporator 11 through the refrigeration capillary tube 7. The first heating wire device 5 is disposed on the outer wall of the bypass pipe 12, and the second heating wire device 6 is disposed on the outer wall of the return gas line of the compressor 1. The outlet of the refrigeration evaporator 11 is connected to the return gas line and leads to the inlet of the compressor 1.

[0033] The second heating wire device 6 is installed between the compressor 1 and the evaporator 11. Specifically, the return gas pipeline is the pipeline connected between the outlet of the evaporator 11 and the inlet of the compressor 1, used to transport the low-temperature, low-pressure refrigerant gas after evaporation and heat absorption in the evaporator 11 back to the compressor 1. Therefore, the second heating wire device 6 is installed on the outer wall of this return gas pipeline, located downstream of the evaporator 11 and upstream of the compressor 1, that is, clearly located on the return gas pipeline between the compressor 1 and the evaporator 11. By heating the outer wall of the return gas pipeline, frost or ice can be effectively prevented from forming on the return gas pipeline due to excessively low temperature during refrigerator operation, ensuring that the refrigerant gas can flow smoothly back to the compressor 1.

[0034] By installing a first heating wire device 5 on the outer wall of the bypass pipe 12 and a second heating wire device 6 on the outer wall of the return gas pipe of the compressor 1, the high-temperature refrigerant generated by the compressor 1 during the defrosting process can enter the refrigeration evaporator 11 through the bypass pipe 12 for hot gas defrosting. At the same time, the heating wire device increases the temperature of the medium in the pipe, which helps to improve the defrosting efficiency. The second heating wire device 6 heats the refrigerant in the return gas pipe, which helps to increase the suction temperature of the compressor 1, thereby mitigating the risk of liquid slugging in the compressor 1.

[0035] In some embodiments, the device further includes a refrigeration capillary tube 8, a refrigeration evaporator 9, and a one-way valve 10; the electric valve 4 is a one-in-three-outlet valve, and also includes a third outlet 43; the third outlet 43 is connected to the inlet of the refrigeration evaporator 9 through the refrigeration capillary tube 8, and the outlet of the refrigeration evaporator 9 is connected to the inlet of the freezer evaporator 11 through the one-way valve 10; the electric valve 4 has four operating states: a defrosting state connected to the first outlet 41, a freezing state connected to the second outlet 42, a refrigeration state connected to the third outlet 43, and a shut-off state in which all outlets are not connected.

[0036] The electric valve 4, acting as a one-in-three-outlet valve, connects its inlet to the high-pressure refrigerant source of the refrigeration system, while its three outlets correspond to different operating circuits. The third outlet 43 is specifically for the refrigeration circuit. When the electric valve 4 switches to refrigeration mode, the high-pressure refrigerant enters the refrigeration capillary tube 8 through the third outlet 43. The refrigeration capillary tube 8, acting as a throttling element, reduces the pressure of the high-pressure liquid refrigerant, which then enters the refrigeration evaporator 9. Inside the refrigeration evaporator 9, the low-pressure refrigerant absorbs heat from the refrigeration compartment and evaporates, thus cooling the refrigeration compartment. The evaporated refrigerant vapor flows out from the outlet of the refrigeration evaporator 9, passes through the one-way valve 10, and enters the inlet of the freezing evaporator 11. The one-way valve 10 plays a crucial one-way guiding role here, allowing refrigerant only to flow from the refrigeration evaporator 9 to the freezing evaporator 11, preventing refrigerant in the freezing evaporator 11 from flowing back into the refrigeration evaporator 9 in other operating states, ensuring the normal operation of the refrigeration circuit and the independence of each circuit. The four operating states of the electric valve 4 precisely control the flow of refrigerant: in defrost mode, only the first outlet 41 is open, allowing high-temperature refrigerant to enter the bypass pipe 12 for defrosting; in freezer mode, only the second outlet 42 is open, allowing refrigerant to enter the freezer capillary tube 7 and the freezer evaporator 11 to achieve freezer compartment cooling; in refrigerator mode, only the third outlet 43 is open, and the refrigerant completes refrigerator compartment cooling along the above path; in the shut-off state, all outlets are closed, and refrigerant supply to each evaporator stops, which can be used for system pressure maintenance or to pause cooling under specific operating conditions. This multi-state design allows the refrigerator's cooling and defrosting functions to be efficiently switched through a single electric valve 4, simplifying the system structure and improving control precision.

[0037] Specifically, the one-way valve 10 is either a ball valve or a needle valve. The ball valve mainly consists of a valve body, valve core, spring, and sealing ring. The valve core uses a high-precision spherical structure, forming a tight fit with the valve seat. When refrigerant flows in from the refrigeration evaporator 9 side, its pressure pushes the ball to overcome the spring force, opening the valve port and enabling flow. When the pressure on the freezing evaporator 11 side is higher than that on the refrigeration side, the spring pushes the ball back to its original position, tightly fitting the valve seat, thus reliably blocking reverse flow. The needle valve achieves flow regulation and one-way sealing through the linear fit between the conical valve core and the valve seat. Its valve core tip design allows for precise control of the flow cross-section, ensuring one-way flow while effectively reducing refrigerant flow resistance and improving system efficiency. Both types of one-way valves 10 use corrosion-resistant brass valve bodies and fluororubber sealing rings to adapt to the working medium and temperature environment of the refrigerator refrigeration system, ensuring long-term stable operation.

[0038] In some embodiments, the first heating wire device 5 and the second heating wire device 6 are both spiral-wound heating wires; the spiral-wound heating wires are continuously spirally wound along the axial direction of the bypass pipe 12 or the return gas pipe, and are tightly attached to the outer wall of the bypass pipe 12 or the return gas pipe.

[0039] Specifically, the spiral diameter of the heating wire is matched to the outer diameter of the bypass pipe 12 or the return gas pipe. During winding, an appropriate spacing is maintained between adjacent spiral coils. This avoids both excessively dense heating wires leading to localized overheating and excessively large spacing causing uneven heating. The tight fit design minimizes heat loss during transfer. When the heating wire is energized, heat is rapidly conducted through the outer wall of the pipe to the interior. For example, during defrosting, this quickly raises the temperature of the refrigerant in the bypass pipe 12, ensuring effective defrosting. In the return gas pipe, it effectively prevents abnormal phase changes in the refrigerant due to excessively low temperatures during reflux, ensuring stable system operation. Furthermore, the spiral winding structure possesses excellent flexibility and adaptability, allowing it to tightly conform to pipe surfaces with varying curvatures. Installation is convenient and secure, and it is not easily loosened or displaced due to vibrations during refrigerator operation.

[0040] In some embodiments, the bypass pipe 12 is embedded inside the foamed insulation layer of the refrigerator body. This helps reduce heat loss as the high-temperature refrigerant flows through the bypass pipe 12 during defrosting, thereby improving the heat utilization efficiency of hot gas defrosting.

[0041] In some embodiments, the first heating wire device 5 and the second heating wire device 6 are integrated on the same flexible insulating substrate; the flexible insulating substrate simultaneously covers the outer wall of the bypass pipe 12 and the return gas pipeline of the compressor 1.

[0042] This integrated design combines the originally separate first heating wire device 5 and second heating wire device 6 onto a single flexible insulating substrate, allowing them to share a common carrier. This flexible insulating substrate does not merely cover a single pipe, but simultaneously and tightly wraps around the outer wall of the bypass pipe 12 and the outer wall of the compressor 1's return gas pipe. In this way, the first heating wire device 5 can specifically heat the bypass pipe 12, while the second heating wire device 6 is responsible for heating the compressor 1's return gas pipe; both achieve collaborative operation on different pipes through the same flexible substrate. This design not only simplifies the installation process, reduces the number of parts, and lowers assembly complexity, but also ensures good contact between the heating wire devices and the outer walls of different pipes, thereby guaranteeing heating efficiency and uniformity. Simultaneously, the shared flexible insulating substrate can better adapt to the routing and layout of the pipes, making the overall structure more compact and saving installation space inside the refrigerator.

[0043] The first heating wire device 5 and the second heating wire device 6 are integrated on the same flexible insulating substrate. This substrate covers the outer wall of both the bypass pipe 12 and the return gas pipe of the compressor 1, which helps to achieve the synchronous installation and fixation of the two heating wire devices through a single substrate, thereby improving the structural integration and assembly efficiency of the defrosting device.

[0044] See Figure 3 This application also provides a defrosting device control method for a refrigerator, applied to the defrosting device for a refrigerator provided in the above embodiments, the method comprising: S100: When the defrosting start conditions are met, control the electric valve 4 to connect the first outlet 41 to conduct the defrosting branch.

[0045] "Meeting the defrost start conditions" typically refers to the moment when the refrigerator's control system determines, based on preset defrost logic, that the defrost program needs to be initiated. These conditions may include, but are not limited to: the compressor 1's cumulative running time reaching a set value, the evaporator surface temperature remaining below a certain threshold for a certain duration, or the frost layer on the evaporator being detected by a specific sensor (such as a frost thickness sensor) to have reached a level requiring removal. Once one or more of these conditions are met, the control system issues a defrost command. At this time, "controlling the electric valve 4 to connect the first outlet 41 to open the defrost branch" means that, under the action of the defrost command, the electric valve 4 in the refrigerator changes its internal passage state, opening the first outlet 41, which might otherwise be closed or leading to other paths. This allows the defrosting medium (such as high-temperature refrigerant vapor) to flow smoothly into the defrost branch (referring to the bypass pipe 12) through the first outlet 41. The opening of the defrost branch is a crucial step in the formal commencement of the defrost process, providing the necessary flow path for the subsequent high-temperature medium to enter the evaporator area for defrosting.

[0046] S200: Controls compressor 1 to run at a first speed to draw refrigerant from the refrigeration evaporator 11.

[0047] S300: Obtain the return gas temperature and environmental parameters of compressor 1, and calculate the dew point temperature based on the environmental parameters.

[0048] The return gas temperature of compressor 1 refers to the temperature at which the refrigerant flows out of the evaporator and returns to the suction port of compressor 1 after completing the refrigeration cycle. This temperature can be collected in real time by a temperature sensor installed on the return gas pipe of compressor 1, reflecting the heat exchange situation inside the evaporator and the superheat of the refrigerant. Environmental parameters mainly include the ambient temperature and humidity outside the refrigerator, which are usually detected by temperature and humidity sensors on the outside of the refrigerator or inside the refrigerator compartment. These parameters are the key basis for calculating the dew point temperature. The dew point temperature is the temperature at which water vapor in the air begins to condense into liquid water under certain ambient temperature and humidity conditions. Its calculation process requires combining the collected ambient temperature and relative humidity and deriving it through specific thermodynamic formulas (such as those based on the Magnus-Tetens formula) to determine the critical temperature value for water vapor condensation in the air under the current environment.

[0049] S310: When the return gas temperature is lower than the dew point temperature, start the first heating wire device 5.

[0050] S320: When the return gas temperature is higher than or equal to the dew point temperature, control the compressor 1 to switch to a second speed lower than the first speed to provide defrosting heat to the refrigeration evaporator 11.

[0051] S400: Obtain the temperature at the inlet of the refrigeration evaporator 11.

[0052] S410: When the temperature at the inlet of the refrigeration evaporator 11 is lower than the dew point temperature, the second heating wire device 6 is activated.

[0053] S420: When the temperature at the inlet of the refrigeration evaporator 11 is higher than or equal to the dew point temperature, the cumulative running time of the compressor 1 during the defrosting stage and the temperature of the refrigeration evaporator 11 are continuously monitored.

[0054] S421: When the cumulative running time reaches the first time threshold, or the temperature of the evaporator 11 reaches the preset temperature threshold, defrosting is determined to be complete, and the electric valve 4 is controlled to switch to the off state.

[0055] By controlling the compressor 1 to run at the first speed during defrosting startup, it helps to extract the low-temperature refrigerant remaining in the evaporator 11, thereby reducing the defrosting heat loss caused by the refrigerant's secondary evaporation and heat absorption in the evaporator. By activating the first heating wire device 5 based on the comparison between the return gas temperature and the dew point temperature, and activating the second heating wire device 6 based on the comparison between the inlet temperature of the evaporator 11 and a preset threshold, the heating wire devices are activated in stages according to the return gas temperature of the compressor 1 and the inlet temperature of the evaporator, which helps to regulate the heat supply during the defrosting process. By detecting the cumulative running time of the compressor 1 and the temperature of the evaporator 11, and determining that defrosting is complete when the conditions are met, the basis for judging the defrosting duration and defrosting endpoint is more sufficient, which helps to balance the energy consumption and defrosting effect during the defrosting process.

[0056] In some embodiments, during the step of controlling the compressor 1 to operate at a first speed, if the condenser 2 is an air-cooled condenser, the fan of the condenser 2 is simultaneously shut off. This helps reduce the heat loss generated by the compressor 1 within the condenser 2, thereby improving the heat supply efficiency of the defrosting branch.

[0057] In some embodiments, the step of controlling the compressor 1 to operate at a first speed includes: controlling the compressor 1 to operate at a speed of 2100 rpm to 3000 rpm; The steps for controlling compressor 1 to switch to the second speed include: controlling compressor 1 to operate at a speed of 1200 rpm to 1500 rpm.

[0058] By controlling the compressor 1 to operate at a first speed of 2100 to 3000 rpm, it helps to quickly extract refrigerant from the evaporator 11 during the initial stage of defrosting; by controlling the compressor 1 to switch to a second speed of 1200 to 1500 rpm, it helps to continuously supply defrosting heat to the evaporator 11.

[0059] In some embodiments, the method further includes: S422: When the cumulative running time has not reached the first time threshold and the temperature of the evaporator 11 has not reached the preset temperature threshold, the compressor 1 is controlled to switch to the second speed. This helps to maintain a continuous supply of defrosting heat to the evaporator 11, thereby improving the integrity of the defrosting process.

[0060] In some embodiments, the first time threshold for determining the completion of defrosting is 20 to 30 minutes, and the preset temperature threshold is 5 to 10 degrees Celsius. This provides a specific basis for controlling the defrosting time and determining the defrosting endpoint.

[0061] As can be seen from the above technical solutions, the embodiments of this application provide a defrosting device and control method for a refrigerator. The defrosting device includes: a compressor 1, a condenser 2, a filter 3, an electric valve 4, a first heating wire device 5, a second heating wire device 6, a freezing capillary tube 7, a freezing evaporator 11, and a bypass pipe 12. The inlet of the condenser 2 is connected to the outlet of the compressor 1, and the outlet of the condenser 2 is connected to the inlet of the filter 3. The electric valve 4 has one inlet and at least two outlets. The inlet of the electric valve 4 is connected to the outlet of the filter 3. The first outlet 41 of the electric valve 4 is connected to the inlet of the freezing evaporator 11 through the bypass pipe 12, and the second outlet 42 of the electric valve 4 is connected to the inlet of the freezing evaporator 11 through the freezing capillary tube 7. The first heating wire device 5 is disposed on the outer wall of the bypass pipe 12, and the second heating wire device 6 is disposed on the outer wall of the return gas pipeline of the compressor 1. The outlet of the freezing evaporator 11 is connected to the return gas pipeline and leads to the inlet of the compressor 1, so as to solve the problems of low defrosting efficiency and high energy consumption of the refrigerator.

[0062] Similar parts between the embodiments provided in this application can be referred to mutually. The specific implementation methods provided above are only a few examples under the overall concept of this application and do not constitute a limitation on the scope of protection of this application. For those skilled in the art, any other implementation methods extended from the solution of this application without creative effort shall fall within the scope of protection of this application.

Claims

1. A defrosting device for a refrigerator, characterized in that, include: It includes a compressor (1), a condenser (2), a filter (3), an electric valve (4), a first heating wire device (5), a second heating wire device (6), a freezing capillary tube (7), a freezing evaporator (11), and a bypass pipe (12). The inlet of the condenser (2) is connected to the outlet of the compressor (1), and the outlet of the condenser (2) is connected to the inlet of the filter (3); The electric valve (4) has one inlet and at least two outlets, and the inlet of the electric valve (4) is connected to the outlet of the filter (3); The first outlet (41) of the electric valve (4) is connected to the inlet of the refrigeration evaporator (11) through the bypass pipe (12), and the second outlet (42) of the electric valve (4) is connected to the inlet of the refrigeration evaporator (11) through the refrigeration capillary tube (7). The first heating wire device (5) is disposed on the outer wall of the bypass pipe (12), and the second heating wire device (6) is disposed on the outer wall of the return gas pipeline of the compressor (1); The outlet of the refrigeration evaporator (11) is connected to the return gas pipeline and leads to the inlet of the compressor (1).

2. The defrosting device for a refrigerator according to claim 1, characterized in that, It also includes a refrigeration capillary tube (8), a refrigeration evaporator (9), and a one-way valve (10). The electric valve (4) is a one-inlet, three-outlet valve, and also includes a third outlet (43). The third outlet (43) is connected to the inlet of the refrigeration evaporator (9) through the refrigeration capillary tube (8), and the outlet of the refrigeration evaporator (9) is connected to the inlet of the freezer evaporator (11) through the one-way valve (10). The electric valve (4) has four operating states: defrosting state connected to the first outlet (41), freezing state connected to the second outlet (42), refrigeration state connected to the third outlet (43), and shut-off state where all outlets are not connected.

3. The defrosting device for a refrigerator according to claim 1, characterized in that, Both the first heating wire device (5) and the second heating wire device (6) are spiral-wound heating wires; The spiral-wound heating wire is continuously spirally wound along the axial direction of the bypass pipe (12) or the return gas pipe, and is tightly attached to the outer wall of the bypass pipe (12) or the return gas pipe.

4. The defrosting device for a refrigerator according to claim 1, characterized in that, The bypass pipe (12) is embedded inside the foamed insulation layer of the refrigerator body.

5. The defrosting device for a refrigerator according to claim 1, characterized in that, The first heating wire device (5) and the second heating wire device (6) are integrated on the same flexible insulating substrate; The flexible insulating substrate is simultaneously wrapped around the outer wall of the bypass pipe (12) and the return gas pipeline of the compressor (1).

6. A method for controlling a defrosting device in a refrigerator, characterized in that, The defrosting device for a refrigerator according to any one of claims 1-5, the method comprising: When the defrosting start conditions are met, the electric control valve (4) is connected to the first outlet (41) to conduct the defrosting branch; The compressor (1) is controlled to run at a first speed to draw refrigerant from the refrigeration evaporator (11); Obtain the return gas temperature and environmental parameters of the compressor (1), and calculate the dew point temperature based on the environmental parameters; When the return gas temperature is lower than the dew point temperature, the first heating wire device (5) is activated. When the return gas temperature is higher than or equal to the dew point temperature, the compressor (1) is controlled to switch to a second speed lower than the first speed to provide defrosting heat to the refrigeration evaporator (11); Obtain the temperature at the inlet of the refrigeration evaporator (11); When the temperature at the inlet of the refrigeration evaporator (11) is lower than the dew point temperature, the second heating wire device (6) is activated. When the temperature at the inlet of the refrigeration evaporator (11) is higher than or equal to the dew point temperature, the cumulative running time of the compressor (1) during the defrosting stage and the temperature of the refrigeration evaporator (11) are continuously monitored. When the cumulative running time reaches the first time threshold, or the temperature of the refrigeration evaporator (11) reaches the preset temperature threshold, defrosting is determined to be complete, and the electric valve (4) is controlled to switch to the cut-off state.

7. The defrosting device control method for a refrigerator according to claim 6, characterized in that, In the step of controlling the compressor (1) to run at the first speed, if the condenser (2) is an air-cooled condenser, the fan of the condenser (2) is simultaneously controlled to shut down.

8. The defrosting device control method for a refrigerator according to claim 6, characterized in that, The step of controlling the compressor (1) to operate at a first speed includes: controlling the compressor (1) to operate at a speed of 2100 rpm to 3000 rpm; The step of controlling the compressor (1) to switch to the second speed includes: controlling the compressor (1) to run at a speed of 1200 rpm to 1500 rpm.

9. The defrosting device control method for a refrigerator according to claim 6, characterized in that, The method further includes: When the cumulative running time does not reach the first time threshold and the temperature of the refrigeration evaporator (11) does not reach the preset temperature threshold, the compressor (1) continues to be controlled to switch to the second speed.

10. The defrosting device control method for a refrigerator according to claim 6, characterized in that, In the conditions for determining that defrosting is complete, the first time threshold is 20 to 30 minutes, and the preset temperature threshold is 5 to 10 degrees Celsius.

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