Defrosting heater for refrigerator evaporator, refrigerator and defrosting control method

Abstract

The invention provides a defrosting heater for a refrigerator evaporator, a refrigerator and a defrosting control method. The defrosting heater comprises the evaporator, a defrosting heater assembly, a first defrosting sensor, a second defrosting sensor and a controller. The defrosting heater assembly is composed of a first heating pipe, a second heating pipe and a third heating pipe. The first heating pipe is arranged at the upper end of the evaporator and embedded in the evaporator body, the second heating pipe is arranged at the lower end of the evaporator, the upper portion of the second heating pipe is close to the bottom of the evaporator, the lower portion of the second heating pipe is close to the water outlet, and a heat conduction wire is arranged at the lowest position of the second heating pipe. The first defrosting sensor is arranged in the body of the evaporator at the upper part of the first heating pipe; and the second defrosting sensor is arranged in the evaporator body between the first heating pipe and the second heating pipe. Through the design of the sectional type heater, synchronous defrosting is achieved at the upper end and the lower end of the fin evaporator in the defrosting process, the defrosting efficiency is improved, and the defrosting time is shortened.

Description

Technical Field

[0001] The present application relates to the field of refrigeration technology, and in particular to a defrost heater for a refrigerator evaporator, a refrigerator, and a defrost control method. Background Art

[0002] With the development of technology and the improvement of people's living standards, refrigerators have become a necessity for every family. At present, most refrigerators are air-cooled refrigerators, which use fans to circulate air for cooling. In air-cooled refrigerators, the cooler lowers the temperature inside the refrigerator by blowing cold air from the fan. This cold air is evenly distributed to various parts of the refrigerator, thereby achieving overall cooling.

[0003] Air-cooled refrigerators have the advantages of fast cooling speed and automatic defrosting, and are gradually replacing direct-cooled refrigerators. However, the evaporator of air-cooled refrigerators needs to be defrosted periodically to ensure the heat exchange performance of the evaporator. In order to achieve reliable defrosting of the evaporator, a heater is usually set at the bottom of the fin evaporator to heat and defrost the evaporator through the combined heat transfer of heat radiation, heat conduction and natural convection. The defrost heater is usually arranged between the evaporator and the water tray in the air-cooled refrigerator, and its arrangement has a great influence on the defrosting performance.

[0004] There are two main types of layout structures of traditional defrost heaters in refrigerators. The first layout structure: the defrost heater is located between the evaporator and the water tray, and its pipe is parallel to the bottom of the evaporator. The second layout structure: the pipe of the defrost heater is inclined from the bottom of the evaporator to the drain outlet of the water tray. In the actual defrosting process, based on the composite heat transfer characteristics, the frost layer on the surface of the evaporator gradually defrosts from bottom to top. The higher the evaporator, the longer the relative defrosting time, the lower the defrosting efficiency of the evaporator, resulting in high energy consumption of the refrigerator, high temperature in the compartment, poor preservation effect and other problems. Summary of the invention

[0005] The present application provides a defrost heater for a refrigerator evaporator, a refrigerator and a defrost control method to solve the current problem that the longer the defrost time of the refrigerator, the lower the defrost efficiency of the evaporator, resulting in high energy consumption of the refrigerator, increased compartment temperature and poor preservation effect.

[0006] In a first aspect, the present application provides a defrost heater for a refrigerator evaporator, the defrost heater comprising:

[0007] An evaporator, a defrost heater assembly, a first defrost sensor, a second defrost sensor, and a controller; the controller is configured to execute a preset refrigerator defrost control method;

[0008] The defrost heater assembly is composed of a first heating tube, a second heating tube and a third heating tube; the first heating tube is arranged at the upper end of the evaporator, the first heating tube is embedded in the evaporator body, the second heating tube is arranged at the lower end of the evaporator, the upper part of the second heating tube is close to the bottom of the evaporator, the lower part of the second heating tube is close to the drain port, and a heat conductive wire is arranged at the lowest part of the second heating tube;

[0009] The first defrost sensor is arranged in the body of the evaporator above the first heating tube, and is used to detect the surface temperature of the upper part of the evaporator;

[0010] The second defrost sensor is disposed in the evaporator body between the first heating tube and the second heating tube, and is used to detect the surface temperature of the evaporator between the first heating tube and the second heating tube.

[0011] In some possible implementations, the third heating tube connects the first heating tube and the second heating tube, and a length of the third heating tube is proportional to a height of the evaporator.

[0012] In some possible implementations, the first heating tube is arranged vertically along the height direction and is horizontal to the pipeline of the evaporator, and the first heating tube is embedded in the evaporator body along the depth direction.

[0013] In some possible implementations, the first heating tube is horizontally arranged along the height direction and is horizontal to the pipeline of the evaporator, and the first heating tube is embedded in the evaporator body along the depth direction.

[0014] In some possible implementations, the first heating tube, the second heating tube and the third heating tube are an integral structure; wherein the third heating tube is a heating element or a non-heating element.

[0015] In some possible implementations, the first heating tube and the second heating tube are of segmented structure, that is, they are two-stage heaters independent of each other.

[0016] In a second aspect, the present application further provides a refrigerator, comprising the defrost heater for the refrigerator evaporator as described in the first aspect.

[0017] In a third aspect, the present application further provides a defrosting control method, the control method comprising:

[0018] Real-time detection of the surface temperature TC1 of the first defrost sensor, when TC1 is greater than or equal to the first preset temperature T1, the first heating tube executes the disconnection mode; otherwise, the first heating tube maintains the connection mode;

[0019] Real-time detection of the second defrost sensor surface temperature TC2, when TC2 is greater than or equal to the second preset temperature T2, and the first heating tube is in the on mode, the second heating tube executes the off mode; otherwise, the second heating tube maintains the on mode;

[0020] When the first heating tube is kept in the disconnected mode, the surface temperature TC1 of the first defrost sensor is detected in real time, and if TC1 is less than or equal to the third preset temperature T3, the first heating tube is put into the connected mode; otherwise, the first heating tube is kept in the disconnected mode;

[0021] When the first heating tube is in the off mode, if the second heating tube is not in the off mode, adjusting the second heating tube to the on mode;

[0022] When the second heating tube is in the disconnection mode, the surface temperature TC2 of the second defrost sensor is detected in real time. If TC2 ≤ the fourth preset temperature T4, the second heating tube is in the connection mode, otherwise the second heating tube maintains the disconnection mode;

[0023] The surface temperature TC1 of the first defrost sensor and the surface temperature TC2 of the second defrost sensor are detected in real time. If TC1 is greater than or equal to the fifth preset temperature T5, and TC2 is greater than or equal to T5, the first heating tube and the second heating tube execute the disconnection mode, end the defrost mode, and execute the water-drying mode; wherein the fifth preset temperature T5 is greater than the first preset temperature T1.

[0024] In some possible implementations, the method further includes:

[0025] If any of the first defrost sensor and the second defrost sensor fails, the system will enter the fault mode, that is, the first heating tube is in the disconnection mode and the second heating tube is in the connection mode. After t1 minutes of operation, the second heating tube will be in the disconnection mode, and the defrost will be frosted and the system will enter the water-spinning mode.

[0026] If the first defrost sensor and the second defrost sensor are normal, the defrost mode operation time meets t2 minutes, the first defrost sensor surface temperature TC1 and the second defrost sensor surface temperature TC2 are not detected, and the defrost will be frosted and enter the water-spinning mode.

[0027] In some possible implementations, the method further includes:

[0028] When executing the water-drying mode, the first heating tube and the second heating tube are both in the disconnection mode, the refrigeration cycle fan starts running for t3 seconds and then turns off, entering the dripping mode;

[0029] When the dripping mode is executed, the first heating tube and the second heating tube are both in the disconnected mode, and the refrigeration cycle fan is in the off mode, which lasts for t4 minutes;

[0030] After t4 minutes, the drip mode ends and the compressor starts to enter normal cooling mode.

[0031] From the above content, it can be seen that the present application provides a defrost heater for a refrigerator evaporator, a refrigerator and a defrost control method, wherein the defrost heater includes: an evaporator, a defrost heater assembly, a first defrost sensor, a second defrost sensor and a controller; the defrost heater assembly is composed of a first heating tube, a second heating tube and a third heating tube; the first heating tube is arranged at the upper end of the evaporator, the first heating tube is embedded in the evaporator body, the second heating tube is arranged at the lower end of the evaporator, the upper part of the second heating tube is close to the bottom of the evaporator, the lower part of the second heating tube is close to the drain outlet, and a thermal conductive wire is arranged at the lowest point of the second heating tube; the first defrost sensor is arranged in the body of the evaporator above the first heating tube, for detecting the upper surface temperature of the evaporator; the second defrost sensor is arranged in the evaporator body between the first heating tube and the second heating tube, for detecting the surface temperature of the evaporator between the first heating tube and the second heating tube. The present application uses a segmented heater design to achieve synchronous defrosting at the upper and lower ends of the fin evaporator during the defrosting process, thereby improving defrosting efficiency and shortening defrosting time; through dual defrost sensor temperature control, the surface temperature uniformity of the fin evaporator is improved, the defrost energy utilization rate is improved, and the defrost reliability is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the technical solution of the present application, the drawings required for use in the embodiments are briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0033] Figure 1 This is a front view of the evaporator and defrost heater assembly in the embodiment of the present application;

[0034] Figure 2 Schematic diagram of the defrosting heating component structure in the embodiment of the present application Figure 1 ;

[0035] Figure 3 This is a side view of the evaporator and defrost heater assembly in the embodiment of the present application;

[0036] Figure 4 Schematic diagram of the defrosting heating component structure in the embodiment of the present application Figure 2 .

[0037] Illustration Description:

[0038] 1-evaporator; 2-defrost heating assembly; 101-first defrost sensor; 102-second defrost sensor; 201-first heating tube; 202-second heating tube; 203-third heating tube; 204-heating wire. DETAILED DESCRIPTION

[0039] The following embodiments are described in detail, and examples thereof are shown in the accompanying drawings. When the following description refers to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The implementations described in the following embodiments do not represent all implementations consistent with the present application. They are only examples of systems and methods consistent with some aspects of the present application as detailed in the claims.

[0040] With the development of technology and the improvement of people's living standards, refrigerators have become a necessity for every family. At present, most refrigerators are air-cooled refrigerators, which use fans to circulate air for cooling. In air-cooled refrigerators, the cooler lowers the temperature inside the refrigerator by blowing cold air from the fan. This cold air is evenly distributed to various parts of the refrigerator, thereby achieving overall cooling.

[0041] Air-cooled refrigerators have the advantages of fast cooling speed and automatic defrosting, and are gradually replacing direct-cooled refrigerators. However, the evaporator of air-cooled refrigerators needs to be defrosted periodically to ensure the heat exchange performance of the evaporator. In order to achieve reliable defrosting of the evaporator, a heater is usually set at the bottom of the fin evaporator to heat and defrost the evaporator through the combined heat transfer of heat radiation, heat conduction and natural convection. The defrost heater is usually arranged between the evaporator and the water tray in the air-cooled refrigerator, and its arrangement has a great influence on the defrosting performance.

[0042] There are two main types of layout structures of traditional defrost heaters in refrigerators. The first layout structure: the defrost heater is located between the evaporator and the water tray, and its pipe is parallel to the bottom of the evaporator. The second layout structure: the pipe of the defrost heater is inclined from the bottom of the evaporator to the drain outlet of the water tray. In the actual defrosting process, based on the composite heat transfer characteristics, the frost layer on the surface of the evaporator gradually defrosts from bottom to top. The higher the evaporator, the longer the relative defrosting time, the lower the defrosting efficiency of the evaporator, resulting in high energy consumption of the refrigerator, high temperature in the compartment, poor preservation effect and other problems.

[0043] Based on this, the present application provides a defrost heater, a refrigerator and a defrost control method for a refrigerator evaporator. Through the segmented heater design, synchronous defrosting is achieved at the upper and lower ends of the fin evaporator during the defrosting process, thereby improving the defrosting efficiency and shortening the defrosting time. Through the temperature control of dual defrost sensors, the surface temperature uniformity of the fin evaporator is improved, the defrost energy utilization rate is improved, and the defrost reliability is improved.

[0044] In some embodiments, a defrost control method is provided, and the defrost control method is applied to a refrigerator, and the control method includes:

[0045] S1: When the refrigerator meets the defrosting conditions, the compressor is controlled to stop, the refrigeration mode is ended, and the defrosting mode is executed; the first heating tube and the second heating tube are synchronized to the on mode, and the defrosting starts;

[0046] S2: Real-time detection of the surface temperature TC1 of the first defrost sensor. If TC1 ≥ the first preset temperature T1, the first heating tube executes the disconnection mode, otherwise the first heating tube maintains the connection mode;

[0047] S3: Real-time detection of the second defrost sensor surface temperature TC2, if TC2 ≥ the second preset temperature T2, and the first heating tube is in the on mode, the second heating tube executes the off mode, otherwise the second heating tube maintains the on mode;

[0048] S4: If the first heating tube is in the disconnected mode when the condition S2 is met, the surface temperature TC1 of the first defrost sensor is detected in real time. If TC1 ≤ the third preset temperature T3, the first heating tube is in the connected mode, otherwise the first heating tube is maintained in the disconnected mode.

[0049] S5: When the condition S2 is met and the first heating tube is in the off mode and the second heating tube is in the on mode, the second heating tube maintains the on mode; if the second heating tube is in the off mode, the second heating tube executes the on mode;

[0050] S6: If the second heating tube is in the disconnected mode when the condition S3 is met, the surface temperature TC2 of the second defrost sensor is detected in real time. If TC2 ≤ the fourth preset temperature T4, the second heating tube is in the connected mode, otherwise the second heating tube maintains the disconnected mode.

[0051] S7: Real-time detection of the surface temperature TC1 of the first defrost sensor and the surface temperature TC2 of the second defrost sensor. If TC1≥the fifth preset temperature T5 and TC2≥T5, the first heating tube and the second heating tube execute the disconnection mode, end the defrost mode, and execute the water-drying mode; wherein the fifth preset temperature T5>the first preset temperature T1.

[0052] In some embodiments, the method further comprises:

[0053] If any of the first defrost sensor and the second defrost sensor fails, the system will enter the fault mode, that is, the first heating tube is in the disconnection mode and the second heating tube is in the connection mode. After t1 minutes of operation, the second heating tube will be in the disconnection mode, and the defrost will be frosted and the system will enter the water-spinning mode.

[0054] If the first defrost sensor and the second defrost sensor are normal, the defrost mode operation time meets t2 minutes, the first defrost sensor surface temperature TC1 and the second defrost sensor surface temperature TC2 are not detected, and the defrost will be frosted and enter the water-spinning mode.

[0055] In some embodiments, the method further comprises:

[0056] When executing the water-drying mode, the first heating tube and the second heating tube are both in the disconnection mode, the refrigeration cycle fan starts running for t3 seconds and then turns off, entering the dripping mode;

[0057] When the dripping mode is executed, the first heating tube and the second heating tube are both in the disconnected mode, and the refrigeration cycle fan is in the off mode, which lasts for t4 minutes;

[0058] After t4 minutes, the drip mode ends and the compressor starts to enter normal cooling mode.

[0059] In some embodiments, Figure 1 As shown, the present application also provides a defrost heater for a refrigerator evaporator, the defrost heater comprising:

[0060] An evaporator 1, a defrost heater assembly 2, a first defrost sensor 101, a second defrost sensor 10 and a controller; wherein the controller in this embodiment is configured with the refrigerator defrost control method in the above embodiment;

[0061] The defrost heater assembly 2 is composed of a first heating tube 201, a second heating tube 202 and a third heating tube 203; the first heating tube 201 is arranged at the upper end of the evaporator 1, the first heating tube 201 is embedded in the body of the evaporator 1, the second heating tube 202 is arranged at the lower end of the evaporator 1, the upper part of the second heating tube 202 is close to the bottom of the evaporator 1, the lower part of the second heating tube 202 is close to the drain port, and a heat conductive wire 204 is arranged at the lowest part of the second heating tube 202;

[0062] The first defrost sensor 101 is disposed in the body of the evaporator 1 above the first heating tube 201 and is used to detect the upper surface temperature of the evaporator 1;

[0063] The second defrost sensor 102 is disposed in the evaporator 1 body between the first heating tube 201 and the second heating tube 202 , and is used to detect the surface temperature of the evaporator 1 between the first heating tube 201 and the second heating tube 202 .

[0064] In some embodiments, the third heating tube 203 connects the first heating tube 201 and the second heating tube 202 , and the length of the third heating tube 203 is proportional to the height of the evaporator 1 .

[0065] The heating power P1 of the first heating tube 201, the heating power P2 of the second heating tube 202 and the heating power P3 of the third heating tube 203 are usually set to P2≥P1≥P3, P3≥0Ω to achieve uniformity and rationality of defrosting of the defrost heater assembly 2.

[0066] In some embodiments, the first heating tube 201 is arranged vertically along the height direction and is horizontal to the pipeline of the evaporator 1 , and the first heating tube 201 is embedded in the body of the evaporator 1 along the depth direction.

[0067] See also Figure 2 , Figure 3 As shown, the first heating tube 201 is arranged vertically along the height direction and is horizontal to the pipeline of the evaporator 1. The first heating tube 201 is embedded in the evaporator body along the depth direction.

[0068] In some embodiments, the first heating tube 201 is horizontally arranged along the height direction and is horizontal to the pipeline of the evaporator 1 , and the first heating tube 201 is embedded in the body of the evaporator 1 along the depth direction.

[0069] See also Figure 3 , Figure 4 As shown, the first heating tube 201 may also be arranged horizontally along the depth direction and be in a horizontal direction with the pipeline of the evaporator 1 , and the first heating tube 201 is embedded in the evaporator body along the depth direction.

[0070] In some embodiments, the first heating tube 201, the second heating tube 202 and the third heating tube 203 are an integral structure; wherein the third heating tube 203 is a heating element or a non-heating element.

[0071] The first heating tube 201, the second heating tube 202 and the third heating tube 203 are of an integral structure. The third heating tube 203 is set as a heating element to assist the evaporator 1 in defrosting, and can also be set as a non-heating element, that is, P3 = 0W, which is only a connection function.

[0072] In some embodiments, the first heating tube 201 and the second heating tube 202 are of segmented structure, that is, they are two-stage heaters independent of each other.

[0073] In some embodiments, the first heating tube 201 and the second heating tube 202 are electrically connected in series by a controller, that is, a simultaneous opening or closing function is achieved.

[0074] In some embodiments, the first heating tube 201 and the second heating tube 202 are electrically connected in parallel by a controller to avoid failure of any one heater while the other heater can work normally, thereby ensuring the reliability of defrosting.

[0075] In some embodiments, the first heating tube 201 and the second heating tube 202 are electrically connected by a controller in an independent manner, that is, the functions of simultaneously turning on or turning on either heater separately are realized.

[0076] In some embodiments, the present application also provides a refrigerator comprising the defrost heater for a refrigerator evaporator according to the above embodiments.

[0077] The present application uses a segmented heater design to achieve synchronous defrosting at the upper and lower ends of the fin evaporator during the defrosting process, thereby improving defrosting efficiency and shortening defrosting time; through dual defrost sensor temperature control, the surface temperature uniformity of the fin evaporator is improved, the defrost energy utilization rate is improved, and the defrost reliability is improved.

[0078] Example

[0079] Determine whether the refrigerator meets the defrosting conditions. If not, the refrigerator continues to execute the normal refrigeration mode; if it meets the defrosting conditions, the compressor stops, the refrigeration ends, and the defrosting mode is executed:

[0080] S1: The first heating tube 201 and the second heating tube 202 are synchronously turned on, and defrosting begins;

[0081] S2: Real-time detection of the surface temperature TC1 of the first defrost sensor 101. If TC1 ≥ T1, the first heating tube 201 executes the disconnection mode. Otherwise, the first heating tube 201 maintains the on mode and sets T1 ≥ -5°C.

[0082] S3: Real-time detection of the surface temperature TC2 of the second defrost sensor 102. If TC2 ≥ T2 and the first heating tube 201 is in the on mode, the second heating tube 202 executes the off mode. Otherwise, the second heating tube 202 maintains the on mode and T2 ≥ 0°C is set.

[0083] S4: If the first heating tube 201 is in the disconnection mode when the condition S2 is met, the surface temperature TC1 of the first defrost sensor 101 is detected in real time. If TC1≤T3, the first heating tube 201 is in the on mode. Otherwise, the first heating tube 201 maintains the off mode. The T3≤T1-N1, N1>0.

[0084] S5: When the condition S2 is met, the first heating tube 201 is in the off mode. If the second heating tube 202 is in the on mode, the second heating tube 202 maintains the on mode. If the second heating tube 202 is in the off mode, the second heating tube 202 executes the on mode.

[0085] S6: If the second heating tube 202 is in the disconnection mode when the condition S3 is met, the surface temperature TC2 of the second defrost sensor 102 is detected in real time. If TC2≤T4, the second heating tube 202 is in the on mode. Otherwise, the second heating tube 202 maintains the disconnection mode. The T4≤T2-N2, N2>0.

[0086] S7: Real-time detection of the surface temperature TC1 of the first defrost sensor 101 and the surface temperature TC2 of the second defrost sensor 102. If TC1≥T5 and TC2≥T5, the first heating tube 201 and the second heating tube 202 execute the disconnection mode, the current defrosting ends, and the water-spinning mode is entered, and T5>T1;

[0087] S8: If any of the first defrost sensor 101 and the second defrost sensor 102 fails, the system enters the failure mode, i.e., the first heating tube 201 is in the disconnection mode, and the second heating tube 202 is in the connection mode. After t1 minutes of operation, the second heating tube 202 is in the disconnection mode, and the defrosting is frosted, and the system enters the water-spinning mode.

[0088] S9: If the first defrost sensor 101 and the second defrost sensor 102 are normal, the defrost mode operation time meets t2 minutes, the surface temperature TC1 of the first defrost sensor 101 and the surface temperature TC2 of the second defrost sensor 102 are not detected, and the defrost is frosted and enters the water-spinning mode;

[0089] S10: Execute the water-drying mode, the first heating tube 201 and the second heating tube 202 are both in the disconnection mode, the refrigeration cycle fan starts running for t3 seconds and then turns off, entering the dripping mode;

[0090] S11: Execute the dripping mode, the first heating tube 201 and the second heating tube 202 are both in the disconnection mode, and the refrigeration cycle fan is in the off mode, which is maintained for t4 minutes.

[0091] S12: Frost forms in drip mode, the compressor starts, and the system enters normal cooling mode.

[0092] It can be seen from the above embodiments that the present application provides a defrost heater for a refrigerator evaporator, a refrigerator and a defrost control method, wherein the defrost heater comprises: an evaporator, a defrost heater assembly, a first defrost sensor, a second defrost sensor and a controller; the defrost heater assembly is composed of a first heating tube, a second heating tube and a third heating tube; the first heating tube is arranged at the upper end of the evaporator, the first heating tube is embedded in the evaporator body, the second heating tube is arranged at the lower end of the evaporator, the upper part of the second heating tube is close to the bottom of the evaporator, the lower part of the second heating tube is close to the drain outlet, and a thermal conductive wire is arranged at the lowest point of the second heating tube; the first defrost sensor is arranged in the body of the evaporator above the first heating tube, for detecting the upper surface temperature of the evaporator; the second defrost sensor is arranged in the evaporator body between the first heating tube and the second heating tube, for detecting the surface temperature of the evaporator between the first heating tube and the second heating tube. The present application uses a segmented heater design to achieve synchronous defrosting at the upper and lower ends of the fin evaporator during the defrosting process, thereby improving defrosting efficiency and shortening defrosting time; through dual defrost sensor temperature control, the surface temperature uniformity of the fin evaporator is improved, the defrost energy utilization rate is improved, and the defrost reliability is improved.

[0093] Similar parts between the embodiments provided in this application can be referenced to each other. The specific implementation methods provided above are only a few examples under the general concept of this application and do not constitute a limitation on the protection scope of this application. For those skilled in the art, any other implementation methods expanded based on the scheme of this application without creative work belong to the protection scope of this application.

Claims

1. A defrosting heater for a refrigerator evaporator, characterized in that: The defrost heater comprises: An evaporator (1), a defrost heater assembly (2), a first defrost sensor (101), a second defrost sensor (102), and a controller; the controller is configured to execute a preset defrost control method; The defrost heater assembly (2) is composed of a first heating tube (201), a second heating tube (202) and a third heating tube (203); the first heating tube (201) is arranged at the upper end of the evaporator (1), the first heating tube (201) is embedded in the evaporator (1) body, the second heating tube (202) is arranged at the lower end of the evaporator (1), the upper part of the second heating tube (202) is close to the bottom of the evaporator (1), the lower part of the second heating tube (202) is close to the drain outlet, and a heat conductive wire (204) is arranged at the lowest point of the second heating tube (202); The first defrost sensor (101) is arranged in the body of the evaporator (1) above the first heating tube (201) and is used to detect the surface temperature of the upper part of the evaporator (1); The second defrost sensor (102) is arranged in the evaporator (1) body between the first heating tube (201) and the second heating tube (202), and is used to detect the surface temperature of the evaporator (1) between the first heating tube (201) and the second heating tube (202).

2. The defrost heater for a refrigerator evaporator according to claim 1, characterized in that: The third heating tube (203) is connected to the first heating tube (201) and the second heating tube (202), and the length of the third heating tube (203) is proportional to the height of the evaporator (1).

3. The defrost heater for a refrigerator evaporator according to claim 1, characterized in that: The first heating tube (201) is arranged vertically in the height direction and in the horizontal direction with respect to the pipeline of the evaporator (1); the first heating tube (201) is embedded in the body of the evaporator (1) in the depth direction.

4. The defrost heater for a refrigerator evaporator according to claim 1, characterized in that: The first heating tube (201) is arranged horizontally in the height direction and is in the same direction as the pipeline of the evaporator (1); the first heating tube (201) is embedded in the body of the evaporator (1) in the depth direction.

5. The defrost heater for a refrigerator evaporator according to claim 1, characterized in that: The first heating tube (201), the second heating tube (202) and the third heating tube (203) are of an integral structure; wherein the third heating tube (203) is a heating element or a non-heating element.

6. The defrost heater for a refrigerator evaporator according to claim 1, characterized in that: The first heating tube (201) and the second heating tube (202) are of segmented structure, that is, they are two-segment heaters that are independent of each other.

7. A refrigerator, characterized in that: The refrigerator comprises the defrost heater for a refrigerator evaporator according to any one of claims 1 to 6.

8. A defrosting control method, characterized in that: The control method comprises: When the refrigerator meets the defrosting conditions, the compressor is controlled to stop, the refrigeration mode is ended, and the defrosting mode is executed; the first heating tube and the second heating tube are synchronized to the on mode, and the defrosting starts; Real-time detection of the surface temperature TC1 of the first defrost sensor, when TC1 is greater than or equal to the first preset temperature T1, the first heating tube executes the disconnection mode; otherwise, the first heating tube maintains the connection mode; Real-time detection of the second defrost sensor surface temperature TC2, when TC2 is greater than or equal to the second preset temperature T2, and the first heating tube is in the on mode, the second heating tube executes the off mode; otherwise, the second heating tube maintains the on mode; When the first heating tube is kept in the disconnected mode, the surface temperature TC1 of the first defrost sensor is detected in real time, and if TC1 is less than or equal to the third preset temperature T3, the first heating tube is put into the connected mode; otherwise, the first heating tube is kept in the disconnected mode; When the first heating tube is in the off mode, if the second heating tube is not in the off mode, adjusting the second heating tube to the on mode; When the second heating tube is in the disconnection mode, the surface temperature TC2 of the second defrost sensor is detected in real time. If TC2 ≤ the fourth preset temperature T4, the second heating tube is in the connection mode, otherwise the second heating tube maintains the disconnection mode; The surface temperature TC1 of the first defrost sensor and the surface temperature TC2 of the second defrost sensor are detected in real time. If TC1 is greater than or equal to the fifth preset temperature T5, and TC2 is greater than or equal to T5, the first heating tube and the second heating tube execute the disconnection mode, end the defrost mode, and execute the water-drying mode; wherein the fifth preset temperature T5 is greater than the first preset temperature T1.

9. The defrosting control method according to claim 8, characterized in that: The method further comprises: If any of the first defrost sensor and the second defrost sensor fails, the system will enter the fault mode, that is, the first heating tube is in the disconnection mode and the second heating tube is in the connection mode. After t1 minutes of operation, the second heating tube will be in the disconnection mode, and the defrost will be frosted and the system will enter the water-spinning mode. If the first defrost sensor and the second defrost sensor are normal, the defrost mode operation time meets t2 minutes, the first defrost sensor surface temperature TC1 and the second defrost sensor surface temperature TC2 are not detected, and the defrost will be frosted and enter the water-spinning mode.

10. The defrosting control method according to claim 8, characterized in that: The method further comprises: When executing the water-drying mode, the first heating tube and the second heating tube are both in the disconnection mode, the refrigeration cycle fan starts running for t3 seconds and then turns off, entering the dripping mode; When the dripping mode is executed, the first heating tube and the second heating tube are both in the disconnected mode, and the refrigeration cycle fan is in the off mode, which lasts for t4 minutes; After t4 minutes, the drip mode ends and the compressor starts to enter normal cooling mode.

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