Efficient back-blowing air fryer

Abstract

The invention relates to an efficient back-blowing air fryer which aims at solving the technical problems that fluid energy loss is large and circulation is disordered and does not act on food due to the fact that fluid energy efficiency of existing similar products is low and turbulent flow is large. The air fryer is characterized in that a hot air mechanism and a heat dissipation mechanism on the back of a metal heat shield of the air fryer are obliquely arranged towards the inner bottom of a fryer body, a groove in the middle of the back of the metal heat shield is rectangular, inner through holes are formed in the inner plane of the groove of the metal heat shield at equal intervals, and the groove of the metal heat shield protrudes towards the back in a triangular mode. A distance of 4-5mm is formed between a surrounding plate face at the position of a groove of the metal heat insulation cover and an impeller face at the position of the hot air impeller in a heat insulation flow guide cover of the hot air mechanism, and through holes are formed in the outer diameter plane of the groove of the metal heat insulation cover, the upper portion of the groove of the metal heat insulation cover and one side of the pot body respectively. And one side in a cavity raised at the top of the metal heat shield above the opening of the inner pot is communicated with a through hole above the groove of the metal heat shield.

Description

Technical Field

[0001] The invention relates to an air fryer, in particular to a high-efficiency back-blown air fryer. Background Art

[0002] An air fryer is a new household appliance that uses high-speed air circulation technology to fry food. Compared to traditional electric fryers, the food it cooks contains 80% less fat. It's easy to clean, safe, and economical, making it a popular choice. Existing air fryers primarily use the following two heating elements for energy transfer: 1. Air fryers with metal tubes as heating elements. Energy transfer within the air fryer is primarily through forced convection, and the intensity of this convection directly determines the product's energy efficiency and heat exchange rate. Therefore, the strength of this convection determines the air fryer's performance. 2. Air fryers with carbon or graphene tubes as heating elements. The energy transfer ratio of radiation to forced convection is approximately 1:1, so fluid strength remains crucial. Some existing air fryers use hot air from the back to overcome the aforementioned problems, such as Chinese patent application No. 202410837162.4, published on August 23, 2024, and titled "Air Fryer with Back Airflow." Another example is Chinese patent application No. 202510171095.1, published on March 28, 2025, and titled "A Multi-Flow Channel Air Fryer." However, these and similar conventional air fryers with back hot air flow suffer from low fluid energy efficiency and the following issues: 1. Back-flow air fryers suffer from significant kinetic energy loss due to the large amount of fluid ejected from the centrifugal impellers hitting the walls of the air fryer, resulting in low energy efficiency. 2. Improper matching between the impeller and the hot air channel results in significant turbulence in the hot air channel, leading to significant fluid energy loss and chaotic flow that does not affect the food. Summary of the Invention

[0003] To overcome the aforementioned shortcomings, the present invention aims to provide a highly efficient back-blown air fryer in the art. This solves the technical problems of existing similar products, such as low fluid energy efficiency and high turbulence, which results in significant fluid energy loss and chaotic flow that does not affect food. This objective is achieved through the following technical solutions.

[0004] A high-efficiency back-blown air fryer, the air fryer is provided with a metal heat insulation cover in the body of the air fryer, the inner diameter of the opening on one side of the body is covered by the metal heat insulation cover to form a hardware heat insulation layer, and the back of the metal heat insulation cover is provided with a hot air mechanism and a heat dissipation mechanism with impellers in sequence; the key points of its structural design are that the hot air mechanism and the heat dissipation mechanism on the back of the metal heat insulation cover are inclined toward the bottom of the body, the groove in the middle of the back of the metal heat insulation cover is rectangular, the inner plane of the groove of the metal heat insulation cover is provided with inner through holes arranged at equal intervals, the groove of the metal heat insulation cover is triangularly protruding toward the back, and the hot air impeller, heating pipe and heat dissipation impeller in the hot air mechanism and the heat dissipation mechanism are parallel, the surrounding plate surface at the groove of the metal heat insulation cover is parallel to the hot air impeller in the heat insulation guide cover of the hot air mechanism The impeller surfaces at the wheel are spaced 4-5 mm apart. The outer sides and bottom plane of the groove of the metal heat insulation cover are respectively provided with equidistant external through holes. The inner and outer through holes of the metal heat insulation cover are sealed to the lower cover opening of the heat insulation guide cover of the hot air mechanism on the back of the metal heat insulation cover. The upper through hole above the groove of the metal heat insulation cover is connected to and sealed with the upper cover opening of the heat insulation guide cover. The upper through hole is arranged on one side of the raised cavity on the top of the metal heat insulation cover above the pot opening at the inner pot of the fryer assembly. The inner through hole at the groove of the metal heat insulation cover is aligned with the pot through holes equidistantly distributed on the back of the inner pot. The outer through hole at the groove of the metal heat insulation cover is aligned with the chamfered edges on both sides of the pot through holes on the back of the inner pot. The exhaust hole on at least one side of the air guide and collecting cover of the heat dissipation mechanism is aligned with the mesh of the machine body and is connected. The ideal distance between the panel surface and the impeller surface is 4-5 mm. Excessive distance can easily generate excessive turbulence, while excessive distance can generate excessive aerodynamic noise. Furthermore, the metal heat shield's groove forms a slanted triangular protrusion, parallel to the hot air impeller, heating pipe, and heat dissipation impeller. Furthermore, the hot air impeller and heating pipe are also tilted, with an angle of 1-15 degrees relative to the vertical notch in the metal heat shield's groove. Furthermore, a second heating pipe can be installed within the raised cavity at the top of the metal heat shield as needed.

[0005] The back corners of the upper through-hole of the heat-insulating deflector are symmetrically provided with triangular cutouts. The cutouts of the heat-insulating deflector serve the following purposes: they guide the flow, allowing the fluid to turn in advance for better ventilation out of the hot air system; and they suppress turbulence, compressing the fluid's movement space within the hot air system and preventing the possibility of excessive turbulence.

[0006] The air duct is located on the back of the heat-insulating hood. The drive shaft of the motor on the back of the air duct extends through the hood and the heat-insulating hood, connecting to both the heat dissipation impeller and the hot air impeller within the hood. The hot air impeller is located inside the heating tube within the heat-insulating hood. The heating tube and motor are connected to the control circuit board via wiring. The heat dissipation impeller is a plastic cross-flow impeller, and the hot air impeller is a multi-blade radial centrifugal impeller. The heating tube is located near the hot air impeller, and the circumference of the hot air impeller is where the fluid intensity in the air fryer is the highest, thereby bringing as much energy generated by the heating tube into the cavity as possible.

[0007] The heat shield's slots, housing the heating tubes and hot air impeller, are square. The heating tubes are mounted within the shield's slots via brackets. The heating tubes are wound around the shield's slots in a square pattern, with brackets separating the tubes at intervals of 2-3mm. This increases fluid velocity when encountering obstacles. Greater fluid velocity reduces turbulence. Maintaining a 2-3mm gap between the heating tubes is crucial. Too small a gap prevents fluid from passing through, while too large a gap prevents fluid from accelerating. A spacing of 2.4mm is optimal.

[0008] The metal heat insulation cover comprises a metal heat insulation lining, a metal heat insulation top cover and a metal heat insulation bottom plate. The front part of one end of the cavity in the top protrusion of the metal heat insulation top cover on the top of the metal heat insulation lining is bent downward, the cavity in the top protrusion of the metal heat insulation top cover is aligned with the inner diameter of the pot mouth of the inner pot of the frying pot assembly below, the back opening of the other end of the cavity in the top protrusion of the metal heat insulation top cover is connected to the cover mouth of the heat insulation guide cover as a whole, the top cover mouth of the metal heat insulation lining and the outer extension edge of the cavity mouth of the cavity in the top protrusion of the metal heat insulation top cover are connected as a whole, and the bottom cover mouth of the metal heat insulation lining is connected to the metal heat insulation bottom plate as a whole. The groove, the inner through hole and the outer through hole are respectively arranged on the back of the metal heat insulation lining. The metal heat insulation lining is provided with a through hole edge protruding toward the side of the machine body opening at the upper through hole formed between the metal heat insulation lining, the metal heat insulation top cover and the heat insulation guide cover, and the through hole edge is higher than the pot mouth of the inner pot of the frying pot assembly below. The structural design of the metal thermal insulation top cover improves the air guiding effect at the upper through hole between the metal thermal insulation lining and the metal thermal insulation top cover.

[0009] The inner through-holes in the groove of the metal thermal insulation lining are arranged equidistantly from the center outward in a rectangular or square pattern. The inner through-holes are each a right-angled trapezoid, while the outer through-holes are equally spaced around the outer sides and bottom plane of the groove and each have a waist-shaped pattern. The maximum arrangement of these inner and outer through-holes serves the same purpose as the corner cut of the thermal insulation shroud: to guide flow and suppress large-diameter turbulence.

[0010] The metal heat insulation cover formed by the metal heat insulation lining, the metal heat insulation top cover and the metal heat insulation bottom plate is provided with a metal sealing plate which is integrated and seals the opening on one side of the machine body. The metal sealing plate is integrated with the opening of the machine body.

[0011] The metal heat-insulating bottom plate at the bottom of the body is provided with two parallel punching grooves, and the punching ribs at the bottom of the inner pot of the fryer assembly correspond to the punching grooves of the metal heat-insulating bottom plate and are installed in the opening on one side of the body.

[0012] The inner wall of the raised top of the metal insulation cover is equipped with three equally spaced, stamped air deflectors. The middle air deflector is positioned toward the front of the machine opening. The air deflectors each increase in height from the machine opening toward the back, forming a triangular shape. The air deflectors further enhance the airflow guidance at the upper through-hole between the metal insulation lining and the metal insulation cover.

[0013] An inserted NTC temperature sensor is provided in the raised cavity on the top of the metal heat-insulating top cover, and the NTC temperature sensor is connected to the control circuit board through a line.

[0014] The metal heat-insulating top cover has an upper through-hole extending from the downwardly curved front portion. This through-hole aligns with and communicates with the upper heat dissipation hole in the fryer assembly's housing. The lower heat dissipation hole in the fryer assembly's housing aligns with and communicates with the through-hole in the metal heat-insulating bottom plate within the machine body at the bottom of the machine body's opening. This structure further improves heat dissipation within the machine body and enhances the ventilation efficiency of the cooling system.

[0015] The present invention has a reasonable structural design and is easy to produce and assemble. In particular, it suppresses the generation of large turbulence, improves the fluid energy efficiency of the product, and thus improves the performance of the air fryer. It is suitable for use as a high-efficiency back-blown air fryer and a structural improvement of similar products. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic cross-sectional structural diagram of an embodiment of the present invention, in which part A is framed.

[0017] Figure 2 yes Figure 1 Magnified view of part A.

[0018] Figure 3 yes Figure 1 Schematic diagram of the rear structure of the fuselage, with the fuselage shell omitted in the figure.

[0019] Figure 4 yes Figure 3 Schematic diagram of the metal insulation top cover structure inside the machine body after the fryer assembly is removed. The dotted lines in the figure are the internal metal insulation lining and the back structure, and the metal insulation bottom plate is omitted.

[0020] Figure 5 yes Figure 4 The figure shows the structure of the metal insulation lining, omitting the metal insulation top cover and the outer shell of the machine body.

[0021] Figure 6 yes Figure 5 Schematic diagram of the structure after the fryer assembly is placed in the fryer, and the back part of the metal insulation lining is omitted in the figure.

[0022] Figure 7 yes Figure 3Schematic diagram of the enlarged structure of the heat insulation guide cover and air guide collecting cover on the back.

[0023] Figure 8 yes Figure 7 Schematic diagram of the front view structure.

[0024] Figure 9 yes Figure 8 Schematic diagram of the three-dimensional structure of the heating tube.

[0025] Figure 10 yes Figure 9 Schematic diagram of the heating tube structure from a top view.

[0026] Serial number and name of the accompanying drawings: 1. Insulated air guide cover, 101. Cutting angle, 2. Heating tube, 3. Hot air impeller, 4. Motor, 5. Heat dissipation impeller, 6. Air guide collecting cover, 7. Metal thermal insulation lining, 701. Groove, 702. Inner through hole, 703. Outer through hole, 704. Through hole edge 8. Metal thermal insulation top cover, 801. Extended edge, 802. Air guide platform, 9. Fryer assembly, 901. Inner pot, 10. Metal thermal insulation bottom plate, 1001. Stamping groove, 11. NTC temperature sensor, 12. Metal sealing plate, 13. Bracket. Implementation Method

[0027] Now, the structure and use of the present invention will be further described in conjunction with the accompanying drawings. Figures 1-10 As shown, a metal heat insulation cover is provided in the body of the air fryer, and the inner diameter of the opening on one side of the body is covered by the metal heat insulation cover to form a hardware heat insulation layer, and a hot air mechanism and a heat dissipation mechanism with impellers are provided in sequence on the back of the metal heat insulation cover; the hot air mechanism and the heat dissipation mechanism on the back of the metal heat insulation cover are inclined toward the bottom of the body, and the groove 701 in the middle of the back of the metal heat insulation cover is rectangular, and the inner plane of the groove of the metal heat insulation cover is provided with inner through holes 702 arranged at equal intervals, and the groove of the metal heat insulation cover is triangularly raised toward the back, and the hot air impeller 3, the heating pipe 2, and the heat dissipation impeller 5 in the hot air mechanism and the heat dissipation mechanism are parallel, and the surface of the enclosure plate at the groove of the metal heat insulation cover and the impeller surface of the hot air impeller in the heat insulation guide cover 1 of the hot air mechanism are parallel. 4-5mm spacing, the outer sides and bottom plane of the groove of the metal heat insulation cover are respectively provided with equidistant external through holes 703, the inner through holes and outer through holes of the metal heat insulation cover are sealed to the cover opening below the heat insulation guide cover of the hot air mechanism on the back of the metal heat insulation cover, the upper through hole above the groove of the metal heat insulation cover is connected to the cover opening above the heat insulation guide cover and is sealed, the upper through hole is arranged on the one side of the raised cavity on the top of the metal heat insulation cover above the pot mouth at the inner pot 901 of the frying pot assembly 9, the inner through hole at the groove of the metal heat insulation cover is aligned with the pot through holes equidistantly distributed on the back of the inner pot, the outer through hole at the groove of the metal heat insulation cover is aligned with the chamfered edges on both sides of the pot through holes on the back of the inner pot, and the exhaust hole on at least one side of the air guide cover 6 of the heat dissipation mechanism is aligned with the mesh of the machine body and is connected.

[0028] Its specific structure is as follows: triangular cut corners 101 are symmetrically provided at the back end corners on both sides of the upper through hole of the above-mentioned heat-insulating air guide cover; the air guide collecting cover is arranged on the back of the heat-insulating air guide cover, and the transmission shaft of the motor 4 on the back of the air guide collecting cover passes through the air guide collecting cover and the heat-insulating air guide cover, and is simultaneously connected to the heat dissipation impeller in the air guide collecting cover and the hot air impeller in the heat-insulating air guide cover. The hot air impeller is arranged on the inner side of the heating pipe of the inner diameter of the heat-insulating air guide cover, and the heating pipe and the motor are connected to the control circuit board through the line; the heat dissipation impeller is a plastic cross-flow fan blade, and the hot air impeller is a multi-blade radial centrifugal impeller. The cover groove in which the heating pipe and the hot air impeller are arranged in the heat-insulating air guide cover is square, and the heating pipe is arranged on the inner diameter of the cover groove of the heat-insulating air guide cover through the bracket 13. The heating pipe is wound in a square shape corresponding to the cover groove of the heat-insulating air guide cover, and the winding part of the heating pipe is spaced by the bracket at a distance of 2-3mm between the pipe fittings.

[0029] The above-mentioned metal heat insulation cover includes a metal heat insulation lining 7, a metal heat insulation top cover 8 and a metal heat insulation bottom plate 10. The front end of the raised cavity of the metal heat insulation top cover on the top of the metal heat insulation lining is bent downward, and the raised cavity of the metal heat insulation top cover is aligned with the inner diameter of the pot mouth of the inner pot of the fryer assembly below. The back opening of the other end of the raised cavity of the metal heat insulation top cover is connected to the cover mouth of the heat insulation guide cover. The top cover mouth of the metal heat insulation lining and the outer extension edge 801 of the cavity mouth of the raised cavity of the metal heat insulation top cover are connected as a whole. The bottom cover mouth of the metal heat insulation lining is connected as a whole with the metal heat insulation bottom plate. The groove, inner through hole and outer through hole are respectively arranged on the back of the metal heat insulation lining. The metal heat insulation lining is provided with a through hole edge 704 protruding toward the side of the machine body opening at the upper through hole formed between the metal heat insulation lining, the metal heat insulation top cover and the heat insulation guide cover. The through hole edge is higher than the pot mouth of the inner pot of the fryer assembly below. The through-holes in the groove of the metal insulation lining are arranged equidistantly from the center outward in a rectangular or square shape. The inner through-holes are rectangular trapezoidal, while the outer through-holes are equidistantly distributed around the outer sides and bottom plane of the groove and are waist-shaped. The metal insulation cover, consisting of the metal insulation lining, metal insulation top cover, and metal insulation bottom plate, has a metal sealing plate 12 integrally connected to the opening of the body. The metal sealing plate is integrally connected to the opening of the body. The metal insulation bottom plate at the bottom of the body has two parallel stamped grooves 1001. The stamped ribs on the bottom of the inner pot of the fryer assembly correspond to the stamped grooves of the metal insulation bottom plate and fit into the opening on the side of the body. The inner wall of the raised top of the metal insulation top cover is provided with three equidistantly arranged and stamped air guide platforms 802, the middle air guide platform is close to the front of the opening side of the body, and the air guide platforms are increased in size and height from the opening side of the body to the back to form a triangle; an NTC temperature sensor 11 is inserted into the cavity of the raised top of the metal insulation top cover, and the NTC temperature sensor is connected to the control circuit board through a line.

[0030] When in use, take out the fryer assembly, put food in the inner pot of the fryer assembly, or put food on the grill in the inner pot, put the fryer assembly back into the body, and then press the buttons on the control panel of the air fryer to start cooking the food.

[0031] According to the above structural features, it is also possible to further provide a through hole on the top cover at the extending edge of the downwardly bent front portion of the metal heat-insulating top cover, the through hole on the top cover is aligned and communicated with the upper heat dissipation hole on the cover shell of the fryer assembly, and the lower heat dissipation hole on the cover shell of the fryer assembly is aligned and communicated with the bottom plate through hole of the metal heat-insulating bottom plate inside the body at the bottom of the opening of the body, thereby further improving the heat dissipation effect of the internal cold air system; and the through hole edge of the metal heat-insulating lining is extended to serve as an air guide plate.

Claims

1. A high-efficiency back-blown air fryer, wherein a metal heat-insulating cover is provided inside the body of the air fryer, the inner diameter of an opening on one side of the body is covered by the metal heat-insulating cover to form a metal heat-insulating layer, and a hot air mechanism with an impeller and a heat dissipation mechanism are sequentially provided on the back of the metal heat-insulating cover; The hot air mechanism and the heat dissipation mechanism on the back of the metal heat insulation cover are inclined toward the bottom of the body, the groove (701) in the middle of the back of the metal heat insulation cover is rectangular, and the inner plane of the groove of the metal heat insulation cover is provided with inner through holes (702) arranged at equal intervals, the groove of the metal heat insulation cover is triangularly raised toward the back, and the hot air impeller (3), the heating pipe (2), and the heat dissipation impeller (5) in the hot air mechanism and the heat dissipation mechanism are parallel, the spacing between the panel surface at the groove of the metal heat insulation cover and the impeller surface at the hot air impeller in the heat insulation guide cover (1) of the hot air mechanism is 4-5 mm, and the outer sides of the groove of the metal heat insulation cover and the bottom plane are respectively provided with outer through holes (702) arranged at equal intervals. The hole (703) is provided, and the inner through hole and the outer through hole of the metal heat insulation cover are sealed to the lower cover opening of the heat insulation guide cover of the hot air mechanism on the back of the metal heat insulation cover. The upper through hole above the groove of the metal heat insulation cover is connected to the upper cover opening of the heat insulation guide cover and is sealed. The upper through hole is provided on one side of the cavity raised on the top of the metal heat insulation cover above the pot opening at the inner pot (901) of the frying pot assembly (9). The inner through hole at the groove of the metal heat insulation cover is aligned with the pot through holes evenly distributed on the back of the inner pot. The outer through hole at the groove of the metal heat insulation cover is aligned with the chamfered edges on both sides of the pot through holes on the back of the inner pot. The exhaust hole on at least one side of the air guide cover (6) of the heat dissipation mechanism is aligned with the mesh of the machine body and is connected.

2. The high-efficiency back-blown air fryer according to claim 1, characterized in that The back end corners on both sides of the upper through hole of the heat-insulating air guide cover (1) are symmetrically provided with triangular cut corners (101).

3. The high-efficiency back-blown air fryer according to claim 1, characterized in that The air guide hood (6) is arranged on the back of the heat insulation hood (1), and the transmission shaft of the motor (4) on the back of the air guide hood passes through the air guide hood and the heat insulation hood, and is simultaneously connected to the heat dissipation impeller (5) in the air guide hood and the hot air impeller (3) in the heat insulation hood. The hot air impeller is arranged on the inner side of the heating tube (2) of the inner diameter of the heat insulation hood, and the heating tube and the motor are connected to the control circuit board through the line; the heat dissipation impeller is a plastic cross-flow impeller, and the hot air impeller is a multi-blade radial centrifugal impeller.

4. The high-efficiency back-blown air fryer according to claim 3, characterized in that The heat insulating guide cover (1) has a square shaped cover groove for the heating pipe (2) and the hot air impeller (3). The heating pipe is arranged at the inner diameter of the cover groove of the heat insulating guide cover through a bracket (13). The heating pipe is wound in a square shape corresponding to the cover groove of the heat insulating guide cover. The winding part of the heating pipe is spaced 2-3 mm apart by the bracket to space the pipe fittings.

5. The high-efficiency back-blown air fryer according to claim 1, characterized in that The metal heat-insulating cover comprises a metal heat-insulating lining (7), a metal heat-insulating top cover (8) and a metal heat-insulating bottom plate (10). The front end of the raised cavity of the metal heat-insulating top cover on the top of the metal heat-insulating lining is bent downward, the raised cavity of the metal heat-insulating top cover is aligned with the inner diameter of the pot mouth of the inner pot (901) of the frying pot assembly (9) below, the back opening of the other end of the raised cavity of the metal heat-insulating top cover is connected to the cover mouth of the heat-insulating guide cover (1), and the top cover mouth of the metal heat-insulating lining is connected to the metal heat-insulating top cover. The outer extension edge (801) of the cavity opening at the raised cavity top of the cover is connected as a whole, the bottom cover opening of the metal insulation lining is connected as a whole with the metal insulation bottom plate, the groove (701), the inner through hole (702), and the outer through hole (703) are respectively arranged on the back of the metal insulation lining, and the metal insulation lining, the metal insulation top cover, and the insulation guide cover are provided with a through hole edge (704) protruding toward the side of the machine body opening, and the through hole edge is higher than the pot opening of the inner pot of the frying pot assembly below.

6. The high-efficiency back-blown air fryer according to claim 5, characterized in that The inner through holes (702) at the groove (701) of the metal thermal insulation lining (7) are arranged equidistantly in a rectangular or square shape from the center outward, and the inner through holes are respectively in the shape of a right-angled trapezoid, and the outer through holes (703) are equidistantly distributed around the outer sides and bottom plane of the groove and are respectively in the shape of a waist.

7. The high-efficiency back-blown air fryer according to claim 5, characterized in that The metal heat insulation cover formed by the metal heat insulation lining (7), the metal heat insulation top cover (8) and the metal heat insulation bottom plate (10) is provided with a metal sealing plate (12) integrally connected to the opening of the machine body and sealing the opening of the machine body. The metal sealing plate is integrally connected to the opening of the machine body.

8. The high-efficiency back-blown air fryer according to claim 5, characterized in that The metal heat-insulating bottom plate (10) at the bottom of the body is provided with two parallel punching grooves (1001), and the punching ribs at the bottom of the inner pot (901) of the fryer assembly (9) correspond to the punching grooves of the metal heat-insulating bottom plate and are installed in an opening on one side of the body.

9. The high-efficiency back-blown air fryer according to claim 5, characterized in that The inner wall of the raised top portion of the metal heat-insulating top cover (8) is provided with three air guide platforms (802) equidistantly arranged and formed by stamping, with the middle air guide platform leaning towards the front of the machine body opening side, and the air guide platforms are increased in size and height from the machine body opening side to the back in a triangular shape.

10. The high-efficiency back-blown air fryer according to claim 5, characterized in that An inserted NTC temperature sensor (11) is provided in the raised cavity on the top of the metal heat-insulating top cover (8), and the NTC temperature sensor is connected to the control circuit board via a line.

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