Composite air stove

Abstract

The utility model belongs to the field of cooking ranges, and particularly relates to an electric cooker. A composite air stove comprises a shell, a heating unit, a control unit, a cooling fan and a temperature sensing element and further comprises an outer hearth, an inner hearth, a motor, fan blades, a fan blade shell and an air guide piece. The outer hearth comprises a cavity which is made of a thermal insulation material and is open at one end, the inner hearth is a cookware heating space and comprises an infrared transmission part, vent holes are formed in the bottom, and the inner hearth and the outer hearth are assembled to form a hollow interlayer which is communicated up and down; the heating unit is arranged in the hollow interlayer, and the power connection end of the heating unit penetrates through the outer hearth to be connected with the control unit. The temperature sensing element is arranged in the hollow interlayer or the inner hearth; the fan blade shell is used for restraining the flow direction of air and is assembled on the inner hearth or the outer hearth; the fan blades are arranged in the fan blade shell, and a shaft of the motor penetrates through the wall of the outer hearth to be connected with the fan blades. The air guide piece is arranged on an air outlet of the fan blade or the inner wall of the fan blade shell; the control unit controls working states of the heating unit and the motor according to working conditions.

Description

Technical Field

[0001] This utility model belongs to the field of stoves, and in particular to an electric stove. Background Technology

[0002] Existing stoves still have shortcomings. Gas stoves, currently the best stoves for Chinese cooking, suffer from safety hazards, exhaust emissions, low efficiency, limited functionality, inability to control temperature, lack of intelligence, fixed location, expensive bottled gas, non-renewable and unclean energy source, and relatively low heat output for household gas stoves. Induction cookers have extremely high thermal efficiency, but they are picky about cookware, heat unevenly, the pot itself heats up, causing localized hot spots that easily burn food, cannot toss the pot, cannot precisely control temperature, lack wok hei (wok aroma) when stir-frying, and have limited functionality. Ceramic cooktops are not picky about cookware material, but they are picky about shape and heat unevenly. The shortcomings of traditional gas stoves include: insufficient heat for stir-frying, inaccurate temperature control, uneven heat distribution, high cost, low efficiency, noise, generation of harmful gases such as ozone and nitrogen oxides, radiation, and limited functionality. In fact, their overall performance is inferior to that of ceramic cooktops. However, my newly developed air cooktop utilizes forced convection heating, far surpassing the aforementioned stoves in terms of heating uniformity and precise temperature control. Its stir-frying effect is comparable to that of a household gas stove, and its thermal efficiency is close to that of an induction cooktop. It is compatible with all types of cookware. However, air cooktops still have two problems: 1. High-power heating requires a large airflow, leading to increased noise and affecting the user experience; 2. Direct grilling or roasting on the cooktop is inconvenient.

[0003] To address the shortcomings of existing stoves, this application proposes a composite air stove that organically combines air circulation heating and radiant heating, achieving a synergistic effect. Based on the Stefan-Boltzmann equation, it is known that the thermal radiation flux is directly proportional to the fourth power of temperature and the surface area of ​​the heating element. Using this law as a theoretical basis, through a rational structural design, the composite air stove primarily utilizes forced convection heating for low-temperature applications such as frying, baking, soup making, and porridge cooking, achieving uniform heating and precise temperature control. For high-temperature applications such as stir-frying and boiling, which require high heat output, the proportion of radiant heating is increased, achieving low-noise, high-heat heating, while forced convection heating also ensures uniform heating. For applications such as grilling and simmering, radiant heating alone can be selected. In summary, through a rational structural design, forced convection heating and radiant heating are organically combined, leveraging their respective strengths and compensating for their weaknesses, thus solving one or more problems existing in existing stoves. Utility Model Content

[0004] To address the shortcomings of existing stove technology, this utility model provides a new technical solution.

[0005] The objective of this utility model is achieved through the following technical solution:

[0006] A composite air cooker includes a shell, a heating unit 5, a control unit 10, a cooling fan 11, and a temperature sensing element 12. It also includes an outer furnace chamber 4, an inner furnace chamber 3, a motor 9, a fan blade 6, a fan blade shell 7, and an air guide component 8. The outer furnace chamber includes a cavity with one open end made of heat-insulating material. The inner furnace chamber is a space for heating cookware and includes an infrared transmission component. Ventilation holes are provided at the bottom of the inner furnace chamber. The inner and outer furnace chambers, when assembled, form a hollow interlayer that is vertically connected. The heating unit 5 is disposed within the hollow interlayer, and the electrical terminal of the heating unit passes through the outer furnace chamber and connects to the heat-insulating element. The control unit is connected; the temperature sensing element is disposed in the hollow sandwich or inner furnace chamber, and the temperature sensing element is connected to the control unit; the fan blade shell is used to constrain the airflow direction, and the fan blade shell is assembled on the inner furnace chamber or outer furnace chamber, or integrated with the inner furnace chamber or outer furnace chamber; the fan blade is disposed in the fan blade shell, the shaft of the motor passes through the outer furnace chamber wall and is connected to the fan blade, and the motor is connected to the control unit; the air guide is disposed at the air outlet of the fan blade or on the inner wall of the fan blade shell; the control unit 10 controls the working status of the heating unit and the motor according to user settings or operating conditions.

[0007] Optionally, it also includes a liquid sensing device 13, which is disposed at one or more locations in the inner furnace or at the bottom of the hollow jacket. It uses changes in capacitance or resistance to sense whether liquid has entered the furnace. The liquid sensing device is connected to the control unit, and the control unit controls the working status of the heating unit and the motor according to the signal from the liquid sensing device.

[0008] Optionally, the heating unit includes an electric heating element 502, a heating element bracket 501, and a neutral electrode cover 503; the electric heating element is mounted on the heating element bracket, the neutral electrode cover is disposed around the electric heating element, the neutral electrode cover is provided with ventilation holes, the neutral electrode cover is connected to the neutral wire, and the neutral electrode cover is electrically isolated from the easily accessible conductive parts of the composite air stove; the control unit also includes a neutral and live wire detection circuit for detecting whether the neutral and live wires are reversed.

[0009] Optionally, it also includes a reflector 16, which is disposed in the inner furnace or the outer furnace to adjust the local radiation intensity.

[0010] Optionally, a drain pipe 17 is also included, which is disposed at the bottom of the outer furnace chamber 4.

[0011] Optionally, it also includes a pot detection device, which includes a furnace ring 18, a switch 19, and a push rod 20; one end of the push rod is connected to the furnace ring, and the other end is connected to the switch. The switch is connected to the control unit, and the control unit controls the working state of the heating unit and the motor according to the switch signal.

[0012] Optionally, the inner furnace chamber 3 includes a glass sheet 301 and a surrounding edge 302; a ventilation hole is opened in the center of the glass sheet, and the glass sheet and the surrounding edge are assembled together to form an inner furnace chamber with the glass sheet as the bottom and the surrounding edge as the wall, and the heating unit 5 is arranged below the glass sheet.

[0013] Optionally, the inner furnace chamber 3 includes a glass tube 303 and a bottom cover 304; the bottom cover has a ventilation hole in the center, and the glass tube and the bottom cover are assembled together to form an inner furnace chamber with the bottom cover as the bottom and the glass tube as the wall, and the heating unit is arranged around the glass tube.

[0014] Beneficial effects

[0015] This utility model discloses a composite air cooker that can achieve one or more of the following beneficial effects: it uses forced convection of hot air to simulate the flame effect of stir-frying in a wok, and uses hot air recycling and circulation heating to achieve energy-saving effects close to those of an induction cooker; it uses forced convection heating combined with thermal radiation heating to achieve a high-power, intense heating effect; it achieves precise temperature control, uniform temperature, is less likely to stick to the pan, and produces less oil smoke, making cooking healthier and simpler; it is compatible with all types of cookware, making it more practical; and it integrates some or all of the functions of a cooker, oven, air fryer, electric grill, teppanyaki grill, and other cookware and appliances. Attached Figure Description

[0016] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0017] Figure 1 A schematic diagram of a composite air cooker structure Figure 1

[0018] Figure 2 A schematic diagram of a composite air cooker structure Figure 2

[0019] Figure 3 A schematic diagram of a composite air cooker structure Figure 3

[0020] Figure 4 A schematic diagram of a composite air cooker structure Figure 4

[0021] Figure 5 A schematic diagram of a heating unit structure

[0022] Figure 6 An exploded view of a heating unit

[0023] Figure 7 A schematic diagram of a reflector structure

[0024] Figure 8 This is a schematic diagram of the drain pipe and pot detection device for a composite air cooker.

[0025] Figure 9This is a partial enlarged view of the boiler inspection device.

[0026] Figure 10 A schematic diagram of a barbecue-style composite air cooker.

[0027] Figure 11 A schematic diagram of an air guide component

[0028] In the picture:

[0029] 1. Upper shell 2. Bottom shell 3. Inner furnace chamber 301. Glass plate 302. Surrounding edge 303. Glass tube 304. Bottom cover 4. Outer furnace chamber 5. Heating unit 501. Heating element bracket 502. Heating element 503. Zero pole cover 504. Ceramic tube 505. Terminal block 506. Pressure plate 6. Fan blade 7. Fan blade shell 8. Air guide 9. Motor 10. Control unit 11. Cooling fan 12. Temperature sensing element 13. Liquid sensing device 14. Knob 15. Cookware 16. Reflector 17. Drain pipe 18. Furnace ring 181. Claw 19. Switch 20. Push rod 21. Spring 22. Oil tray Detailed Implementation

[0030] It should be noted that, without conflict, the embodiments and features described in this application can be combined with each other, and any solution that can be easily conceived through this utility model is within the protection scope of this utility model. The utility model will be further described below with reference to the accompanying drawings and embodiments.

[0031] Example 1

[0032] A composite air cooker includes a shell, a heating unit 5, a control unit 10, a cooling fan 11, and a temperature sensing element 12. It also includes an outer furnace chamber 4, an inner furnace chamber 3, a motor 9, a fan blade 6, a fan blade shell 7, and an air guide component 8. The outer furnace chamber includes a cavity with one open end made of heat-insulating material. The inner furnace chamber is a space for heating cookware and includes an infrared transmission component. Ventilation holes are provided at the bottom of the inner furnace chamber. The inner and outer furnace chambers, when assembled, form a hollow interlayer that is vertically connected. The heating unit 5 is disposed within the hollow interlayer, and the power terminal of the heating unit passes through the outer furnace chamber and... The control unit is connected; the temperature sensing element is disposed in the interlayer or inner furnace chamber, and the temperature sensing element is connected to the control unit; the fan blade shell is used to constrain the airflow direction, and the fan blade shell is assembled on the inner furnace chamber or outer furnace chamber, or integrated with the inner furnace chamber or outer furnace chamber; the fan blade is disposed in the fan blade shell, the shaft of the motor passes through the outer furnace chamber wall and is connected to the fan blade, and the motor is connected to the control unit; the air guide is disposed at the air outlet of the fan blade or on the inner wall of the fan blade shell; the control unit 10 controls the working status of the heating unit and the motor according to user settings or operating conditions.

[0033] Most of the accompanying drawings in this application are cross-sectional schematic diagrams; the internal structure can only be seen by cutting through them. For example... Figure 1 As shown, the outer shell of the composite air stove is composed of the upper shell 1 and the bottom shell 2. This is a shell structure form of a single-burner stove. If the remaining parts except the upper shell and the bottom shell are installed in other structures, the structures that play the role of fixing and electrical insulation can be regarded as the outer shell. Figure 1 In the middle, the outer furnace chamber 4 is the component filled with cross-sectional lines of the same slope and spacing as indicated by the serial number. It can be made of heat insulation materials with certain waterproof performance and strength, such as refractory cement and refractory clay. To enhance the heat insulation effect of the above materials, lightweight high-temperature resistant microporous materials such as silica aerogel particles and expanded perlite can also be mixed in. If the heat insulation material itself is not waterproof, such as the formula of the heat insulation material in the heating plate of an electric ceramic stove, its strength is very low and its water absorption is very strong, and it cannot be used as a structural component independently. In this case, a shell made of metal material can be made in the inner layer of the outer furnace chamber for waterproofing and supporting the structure, and the heat insulation material is placed in the outer layer as a heat insulation layer. The outer furnace chamber 4 can also be made of metal material to first make a hollow shell, and then fill it with flowable heat insulation materials such as expanded perlite, glass microspheres, and nano aerogel. Figure 1 As shown, the top of the outer furnace chamber 4 is open, which is used to place the inner furnace chamber 3 and other parts such as the heating unit 5 and the fan blade 6. The bottom also has corresponding holes to allow the shaft of the motor 9, the terminals of the heating unit to pass through, and the temperature sensing element 12 to be assembled. Figure 1 The inner furnace chamber 3 is made of high-temperature resistant infrared-transmitting material, mainly microcrystalline glass, quartz glass, and borosilicate glass. The main requirement is efficient infrared transmission, allowing the heating unit 5 to heat cookware or food via radiation. It must also be heat-resistant with a low coefficient of thermal expansion to prevent cracking due to uneven heating. A certain structural strength is also necessary. Besides the aforementioned glass materials, some ceramic materials may also be used. The concave space of the inner furnace chamber accommodates various cookware. If hot air circulation is not considered, a burner rack could be installed on the nozzle like in a gas stove, but this would waste hot air and result in low thermal efficiency. This structure is merely a simple modification and is within the scope of this invention. Ventilation holes are provided at the bottom of the inner furnace chamber 3. Figure 1 The central air guide component 8 is mounted on this ventilation hole, and the fan blade 6 drives air through this ventilation hole to blow out heated cookware or food. For example... Figure 1 As shown, the inner furnace chamber 3 is assembled within the outer furnace chamber 4, forming a hollow interlayer between them. This hollow interlayer serves as a channel for hot air circulation. The arrows in the diagram indicate the direction of airflow. When no cookware is placed inside, the air drawn into the hollow interlayer is primarily cold outside air, without any air circulation within the stove. Figure 3As shown, after the cookware is placed on the stove, hot air circulates within the inner furnace chamber and the hollow sandwich layer under the action of the fan blades. At this time, the hot air leaks out almost completely, achieving high thermal efficiency. The heating unit 5 is installed in this hollow sandwich layer to prevent people from touching live parts. Simultaneously, the heating unit 5 is located at the suction end of the fan blade 6, resulting in more even airflow and less resistance. If the heating unit were located at the blowing end of the fan blade, the airflow would be very uneven and would create significant resistance, greatly reducing airflow. The heating unit's terminal 505 passes through the outer furnace chamber, and the control unit 10 is connected to this terminal to control the on / off state and power of the heating unit 5. Under these high-temperature conditions of several hundred degrees Celsius, the temperature sensing element 12 is generally a thermocouple, although infrared sensing can also be used. Figure 1 The temperature sensing element shown is disposed in the hollow sandwich layer, and its optimal location is where hot air converges, so that it measures the average temperature of the air. Functionally, the temperature sensing element could also be disposed in the inner furnace chamber, but this is not structurally advantageous, so it is not shown in the attached diagram. The temperature sensing element 12 is connected to the control unit 10, providing temperature data to the control unit, which uses this data to control the on / off state or power of the heating unit 5. Multiple temperature sensing elements can be disposed, such as... Figure 2 As shown, a temperature sensing element 12 is also installed at the top of the hollow sandwich layer. When only radiant heating is used, due to the lack of hot air circulation, the temperature sensing element at the bottom differs greatly from the actual temperature of the heating unit 5, and may even be completely worthless. In this case, the temperature sensing element at the top is used as the reference. The fan blade shell 7 is used to constrain the airflow direction. When the fan blade 6 is a centrifugal fan blade, the air is thrown outwards under the action of centrifugal force. At this time, the slope of the side wall of the fan blade shell must be used to guide the airflow in the set direction. Even if the fan blade 6 is an axial flow fan blade or an oblique flow fan blade, in the structure of a composite air stove, the airflow is affected by the inner and outer furnace chambers, heating units, etc., which is completely different from an electric fan. It does not necessarily blow in the axial direction, and the fan blade shell must also be used to constrain the airflow direction. The fan blade shell is a hollow shell that runs through the front and back, generally a hollow cylinder or cone. The taper can be determined according to the structure of the fan blade. In order to better prevent backflow, the taper of the tail cone at the air inlet end can be increased. Figure 1 The tail cone shown has an increased taper; the blade shells in the attached drawings of this application all have a taper. If the gap between the axial flow blade and the blade shell is small enough, it is also feasible for the blade shell not to have a taper. The specific structure can be determined through actual testing. Figure 1 The blower blade shell 7 is assembled on the inner furnace 3. As shown in the diagram, the inner furnace is made of glass with a relatively thick wall, while the blower blade shell is made of metal with a very thin wall. Figure 2The fan blade shell and the inner furnace are integrated into one piece. As can be seen from the figure, they have the same wall thickness. Therefore, the fan blade shell 7 in the claim does not necessarily need to be an independent component. It can be part of other parts, as long as it can guide the airflow of the fan blade 6 and direct the air to the cookware. Figure 2 The system also includes a wind net 23. The purpose of the wind net is to prevent foreign objects larger than a certain size from falling into the blade housing, thus preventing the blades from getting stuck or damaged. Figure 3 The blower shell is assembled on the outer furnace chamber. It can be seen that the bottom of the blower shell is connected to the outer furnace chamber 4 by several ribs. The air guide 8 is assembled on the air outlet end of the blower shell, while only the air mesh 23 is assembled on the ventilation hole at the bottom of the inner furnace chamber 3. Figure 3 This structure also facilitates maintaining the concentricity of the fan blades and their housing, because both the motor and the fan blade housing are mounted on the outer furnace chamber, essentially using the same reference. Similarly, the fan blade housing can also be integrated with the outer furnace chamber. In short, the purpose of the fan blade housing is to constrain the air driven by the fan blades from the ventilation holes at the bottom of the inner furnace chamber towards the cookware. Any structure is acceptable as long as this purpose is achieved; the best approach is to have it coaxial with the ventilation holes at the bottom of the inner furnace chamber. Figures 1 to 3 As shown, the fan blade 6 is assembled inside the fan blade housing 7, and the motor 9 is assembled at the bottom of the outer furnace chamber, coaxially mounted with the fan blade. The motor shaft passes through the outer furnace chamber wall and connects to the fan blade. The motor is connected to the control unit 10, which controls the start / stop or speed of the motor 9 according to the stove's settings and operating conditions. Figure 1 As shown, the air guide 8 is located at the air outlet of the fan blade. Its function is to reduce cyclone. The rotating air generates centrifugal force, and after leaving the constraint of the fan blade shell, it will be thrown in all directions instead of being blown directly towards the bottom of the pot. The air guide can act like... Figure 11 The air guide spokes are designed as a wheel structure. This type of air guide can be used on any fan blade. Alternatively, the air guide can be installed as ribs on the inner wall of the fan blade housing, restricting airflow rotation from the source. This is primarily used in centrifugal fan blades. The control unit 10 controls the operating status of the heating unit and motor according to user-set parameters or operating conditions. For example, if the user sets a grilling mode or "radiation only," the motor will not operate, and food will only be grilled via superheated radiation. When the user sets different modes such as stir-frying, frying, steaming, etc., the heating temperature, power, and motor speed of the heater will all be different. Of course, there are also abnormal operating conditions of the stove; the control unit will also control the heating unit or motor to shut down or reduce power based on these abnormal signals. Figure 1 The cooling fan 11 shown is used to cool the control unit 10, the motor 9, and the inside of the stove.

[0034] Figure 1The composite air cooker shown has two methods for heating cookware: one is forced convection heating of the cookware by hot air under the action of fan blades, and the other is direct heating of the cookware by infrared rays generated by the heating unit through the inner furnace 3. Forced convection is the primary method, ensuring even heating, precise temperature control, and rapid feedback for any cookware. Thermal radiation serves as a supplement, enabling high-power heating with low fan noise. However, both forced convection and thermal radiation have limitations in terms of heating area, making it difficult to utilize maximum power, especially when the cookware material or walls are too thick and have poor thermal conductivity, resulting in insufficient heat for Chinese stir-frying. The uniformity of thermal radiation heating is affected by the shape of the cookware, the distance from the heat source, the angle of incidence, and the integral of radiation, making it difficult to achieve uniform heating and precise temperature control. In a test on a concave ceramic cooker with a round-bottomed cookware, the temperature in the approximately 8cm diameter area of ​​the cookware reached nearly 600 degrees Celsius, while the temperature in the approximately 13cm diameter area dropped sharply to around 300 degrees Celsius, resulting in a very poor cooking experience—the center emitted smoke while the edges remained sparsely heated. Meanwhile, while ensuring a long lifespan for the heating element and reliable operating temperature for the glass, the heat radiation power transmitted over a given area is limited. For example, in a test of a Joyoung ceramic cooktop with a power of 2.2KW, the power was continuously lowered during heating to maintain the heating element temperature within a safe range, taking 11 minutes to boil 1.5 liters of water at a base temperature of 28 degrees Celsius. In contrast, an induction cooktop with the same power only took 5 minutes. Unknown brands of ceramic cooktops achieve greater power transmission by increasing the temperature of the heating element, as heat radiation power is proportional to the fourth power of temperature. While this significantly improved boiling time, the heat output was still too low for the demands of stir-frying in Chinese cuisine. Furthermore, the lifespan of the heating element and the potential for the glass to explode remain questionable. In this regard, the compromises made by well-known brands are likely more reliable. Moreover, heat radiation heating cannot achieve precise temperature control. Tests showed that regardless of the temperature sensor's placement, the readings differed significantly from the actual temperature of the cookware, rendering them completely useless as a reference. Forced convection heating, on the other hand, can achieve precise temperature control and also offers very high uniformity, ensuring that the temperature of the heated areas of the pot remains largely consistent, with a maximum temperature difference of only about 30 degrees Celsius. Cooking techniques such as frying, simmering, stewing, boiling porridge, and making soup require a high degree of temperature uniformity and precise control in the pot. For example, when frying eggs, pancakes, or fish, it's desirable for the heated areas of the pot to maintain a consistent temperature so that the pot or food doesn't need to be moved frequently to cook properly. The same applies to simmering foods, such as sweet potatoes, glutinous rice cakes, and corn on the cob; if the stove cannot precisely control the temperature, it must be monitored and the food turned frequently. Similarly, when cooking rice, porridge, or rice paste, if precise temperature control is not achieved, the food is prone to burning.Rice cookers, because they can sense the temperature of the pot, can automatically control the cooking process, enabling automatic rice and porridge cooking without human intervention. Electric griddles, because they can sense the temperature of the heating surface and heat evenly, can also automatically fry pancakes without human intervention. Electric ovens and air fryers, on the other hand, allow hot air and heat radiation to act directly on the food without the pot in between, making them easier to control. Therefore, for cooking utensils to be automatically controlled, both precise temperature control and even heating are indispensable. Gas stoves and electric flame stoves cannot adjust the combustion temperature, while induction cookers and ceramic cooktops heat unevenly and cannot measure the actual temperature of the pot. Furthermore, the types of cookware used for stir-frying vary, with different heating, heat transfer, and heat dissipation conditions, making it difficult for previous stoves to achieve precise temperature control and even heating. The composite air fryer of this application, however, has undergone more than a year of testing and use, achieving precise temperature control and even heating. With these two advantages, cooking is less likely to stick to the pan, produces less smoke, and makes cooking healthier and simpler.

[0035] Actual measurements show that, under identical conditions, an air stove using only forced convection heating can only utilize 2400W of power, while a combined air stove incorporating heat radiation can utilize 3500W or even higher. Besides the heat dissipation from the cookware itself, the 3500W heat output of the stove is roughly equivalent to a 7000W gas stove, far exceeding the heat output of a typical 4.2KW or 5.2KW gas stove. Although gas stoves are labeled with a 63% energy efficiency rating, this is based on tests using new aluminum pots under standard conditions. However, users typically use iron pots, which are prone to rust and grease buildup, severely impacting heat transfer. Furthermore, the range hood's suction causes significant heat loss, reducing the actual efficiency of the gas stove to approximately 40%. The efficiency is even lower when using ceramic pots or soup pots. In the combined gas stove of this application, the opening of the combustion chamber is sealed after the cookware is placed on it. Regardless of the type of cookware, the thermal efficiency is the same. If the cookware has poor heat conduction, the heat that cannot be absorbed by the cookware will continuously accumulate in the combustion chamber, causing the temperature in the combustion chamber to rise continuously and exceed the temperature set value. The control unit 10 will then reduce the power to keep the temperature in the combustion chamber at the set temperature. However, the unused power of the gas stove is all dissipated into the surrounding environment, resulting in a great waste of energy. It also causes cooking to be very hot in spring, summer, and autumn, often leaving the user drenched in sweat.

[0036] Besides strong heat, even temperature, and controllable temperature, a good cooktop also needs rapid feedback when adjusting the heat. Among currently popular cooktops, induction cooktops have the fastest feedback, followed by gas cooktops, while ceramic cooktops are significantly slower. Hybrid air cooktops are similar to ceramic cooktops in the initial one or two minutes of heating up a cold stove, but during the subsequent cooking process, adjusting the heat is much faster than with gas cooktops. This is because hybrid air cooktops primarily heat the cookware through forced convection of hot air, with radiation only playing a supplementary role. Adjusting the airflow quickly translates into increased heat, whereas heat radiation can only be adjusted through shielding, a feature currently lacking in ceramic cooktops.

[0037] Being compatible with all cookware is a basic requirement for any cookware stove. Induction cooktops are highly selective about the type and material of cookware they use. While their main problems are uneven heating, localized hot spots, and difficulty in controlling the heat, leading to poor cooking, this incompatibility is still a significant issue. Ceramic cooktops are compatible with all cookware materials, but they are selective about the shape of the cookware. Gas stoves, on the other hand, are completely compatible with all cookware. The combined air cooktop described in this application is similar to a gas stove, such as... Figure 2 The large soup pot shown Figure 3 The round-bottomed pot shown Figure 4 All the pans shown can be used, and they are compatible with all materials. Because the temperature is controllable—for example, users can set the temperature to 50, 60, or 100 degrees Celsius—it can even heat a paper bowl. The composite air cooker has been tested using a foil bowl to make clay pot rice, and the results are the same as using a ceramic pot on a gas stove. For cookware that is not picky, the composite air cooker even surpasses the gas stove. Figures 2 to 4 The pots and pans shown are all larger than the opening of the stove's firebox, but as long as they are like... Figure 8 With the addition of the 181 locking claw, appliances smaller than the cooktop opening can also be used. However, appliances smaller than the cooktop opening will cause hot air leakage, resulting in heating efficiency as low as a gas stove. Of course, for appliances smaller than the opening, users can choose radiant heating only, which still has a decent heating efficiency of around 70%, because radiant heating does not involve a large amount of hot air carrying away heat. Therefore, the combination of two heating methods in a hybrid air cooktop can solve many practical problems.

[0038] Induction cookers have an actual thermal efficiency more than twice that of gas stoves (as mentioned earlier, the so-called 63% energy efficiency of gas stoves is based on laboratory measurements using clean aluminum pots; the actual efficiency is only around 40%). However, given the opportunity, users still primarily use gas stoves for cooking. This demonstrates that users prioritize the taste of their food over energy efficiency, as cooking consumes a significant portion of energy, making the thermal efficiency of cooktops crucial for society. The composite air cooker of this application, with no hot air leakage and all heat radiation contained within the combustion chamber, has a thermal efficiency dependent solely on the insulation of the outer combustion chamber 4 and the cooker's own heat storage capacity. A better insulation solution can achieve a thermal efficiency approaching that of an induction cooker. In terms of cooking performance, energy saving, intelligence, and safety, the composite air cooker surpasses gas stoves; it's only a matter of time before it replaces gas stoves.

[0039] A liquid sensing device 13 can also be added. This device is located at one or more points in the inner furnace or the bottom of the hollow sandwich layer. It detects whether liquid has entered the furnace by detecting changes in capacitance or resistance. The liquid sensing device is connected to the control unit, which controls the operating status of the heating unit and the motor based on the signal from the liquid sensing device. After placing the cookware, the opening at the top of the composite air stove is essentially sealed. Even if the cookware boils and overflows during heating, water cannot enter the furnace. However, during the removal of the cookware, soup may spill into the stove, or if the cookware is too small and does not form a seal with the stove, soup may overflow into the furnace. There is also the possibility that the pot may break, allowing soup to enter the furnace. In all these possible situations, it is essential to ensure that no electrical leakage occurs. Figure 1 The structure shows that when too much liquid gets into the heating unit 5, it may cause leakage if the heating unit does not have a waterproof structure. This increases the risk of electrical leakage. Figure 2 The liquid sensing device 13 shown can cut off the power supply to the heating unit by the control unit 10 after sensing that liquid has entered the furnace, thus disconnecting both the live and neutral wires and preventing leakage. The motor can also be shut off simultaneously when liquid is sensed to prevent hot liquid from splashing and scalding people under the action of the fan blades, and to prevent the fan blades from being overloaded and damaging the motor. Figure 3The liquid sensing device shown has two electrodes and can sense liquid using either resistance or capacitance. If resistance is used, the liquid must be conductive. When conductive liquid connects the two electrodes, a circuit is formed between them. The control unit uses this to determine that liquid has entered, thereby disconnecting the power supply to the heating unit 5 and shutting down the motor. If capacitance is used, the conductivity of the liquid is irrelevant. Furthermore, the two electrodes can be coated with a ceramic layer or mounted in a high-temperature insulating shell to prevent oxidation. When liquid enters between the two electrodes, it changes the dielectric between the capacitors, thus altering the capacitance. The control unit 10 can sense whether liquid has entered by sensing the capacitance or the charging / discharging action of the capacitor. Figure 2 The liquid sensing device can also be installed in the inner furnace chamber 3, and the reaction speed will be even faster, because the liquid must pass through the inner furnace chamber before entering the outer furnace chamber. The principle is exactly the same, but it is not shown in the attached figure. Figure 3 The liquid sensing device shown is a capacitive sensing device. The sensing electrode in the diagram is attached to the bottom of the inner furnace. When liquid or even conductive solid falls into the sensing electrode, it is sensed just like a human hand touching a capacitive sensing switch. The control unit 10 cuts off the power to the heating unit 5 to ensure safety. Figure 3 Liquid sensing devices can also be like Figure 4 It is also located at the bottom of the outer combustion chamber. A liquid sensor is not a necessary feature, as multi-functional air cooktops can prevent electrical leakage in many other ways. In commercial applications, even adequate protection of the cooktop itself is not necessary; relying solely on external environmental protection is sufficient. The liquid sensor simply provides a cheap and reliable leakage protection method that does not depend on external environmental factors.

[0040] The hot air blown into the cookware 15 by forced convection heating will have a slightly lower temperature in the center area (approximately 5 cm in diameter) than the surrounding area. Although the air guide 8 uses a tapered design to direct the airflow towards the center, it cannot completely solve the problem of the center temperature being slightly lower than the surrounding area. When frying an egg, it is desirable for the center temperature to be slightly higher than the surrounding area. Therefore, a reflector 16 can be added, which is installed in the inner or outer furnace chamber to adjust the local radiation intensity. Figure 7 A magnified view shows a portion of the stove, such as Figure 7As shown, the reflector 16 is installed in the inner furnace chamber. The reflector in the illustration is a conical ring. To avoid affecting the dotted lines representing radiation, only a small portion of the reflector is shown in the illustration. The dotted lines in the illustration represent part of the heat radiation emitted from the heating unit that is reflected by the reflector 16 to the central area of ​​the cookware 15. Due to the obstruction of structural components such as the fan casing, the center of the cookware cannot receive direct heat radiation from the heating unit 5. Only forced convection hot air can heat it. By reflecting part of the heat radiation to the center of the cookware through the reflector, the temperature of the center of the cookware can be increased. By adjusting the area or angle of the reflector 16, the heat distribution of the cookware can be made to achieve an ideal state. The reflector can be made of stainless steel and enameled to increase the reflective effect. Depending on the structure of the stove, the reflector can be installed in other places, such as on the outer furnace chamber or in the hollow sandwich between the inner and outer furnace chambers. The reflector 16 is an improvement feature rather than a necessary feature.

[0041] A drain pipe 17 can also be added, which is located at the bottom of the outer furnace chamber 4. Drainage for the stove is essential in residential settings because users, such as children, the elderly, and others with limited dexterity, may easily spill water into the stove when moving the cookware. However, it is not essential in commercial settings, such as in a canteen where large pots of food are cooked; the cookware is rarely moved after being placed on the stove, making it unlikely that any soup or water will enter the stove. Therefore, a drain pipe is not a necessary feature of the stove in this application. Figure 8 As shown, two drain pipes, approximately 17 inches long, are located at the bottom of the outer furnace chamber 4. When water enters the furnace chamber, it is drained out through the drain pipes to the outside of the stove. Because the drain pipes are on the suction side of the fan blades, they are generally under negative pressure when the fan blades rotate. Hot air generally does not overflow from the drain pipes. If under negative pressure, cold air would be drawn in from the outside. However, because the stove is in a somewhat sealed state after the pot is placed on it, the escape of hot air is limited, so the amount of cold air drawn in from the outside is also limited. There can be one or more drain pipes. The number and size of the drain pipes should be considered in relation to the thermal efficiency of the stove. Of course, if there is enough space at the location where the stove is installed, the outlet of the drain pipe can be connected to a container to hold the spilled soup. If the connected container is sealed, it is impossible to draw in cold air, so the drain pipe can be enlarged to facilitate drainage.

[0042] A pot detection device can also be added, which includes a furnace ring 18, a switch 19, and a push rod 20; one end of the push rod is connected to the furnace ring, and the other end is connected to the switch. The switch is connected to the control unit, and the control unit controls the working status of the heating unit and the motor according to the switch signal. Figure 8 A schematic diagram of the boiler inspection device is provided. Figure 9This is a magnified view of a portion of the design. The furnace ring 18 is used to support the cookware. When a cookware is placed on it, its weight presses down on the furnace ring 18, which in turn presses down on the push rod 20. The push rod triggers the switch 19, and the control unit 10 receives the signal from the switch, thus knowing that a cookware has been placed on it. When the cookware is removed, the rebound force of the switch itself or the spring 21 overcomes the weight of the furnace ring 18, lifting the push rod. The switch 19 returns to its untriggered state, and the control unit thus determines that the cookware has been removed. The control unit can control the operating status of the heating unit and motor based on whether a cookware is placed on it. For example, when the cookware is removed, the motor can be turned off after a certain number of seconds, the heating unit can operate at low power to maintain the temperature or be turned off, and then automatically shut down after another certain period of time. This does not affect the tossing operation and can save energy or achieve more intelligent control. A cookware detection device is not a necessary feature.

[0043] Example 2

[0044] In Example 1, if soup enters the furnace, the leakage protection relies on the ground wire, leakage protection switch, liquid sensing device, and the environment. The ground wire and leakage protection switch depend on the external electrical environment and may not be present. The liquid sensing device depends on the normal functioning of the control unit 10; if this function fails, protection is lost. Therefore, its safety protection is not absolute. This example aims to further enhance the anti-electric shock effect and ensure sufficient safety by adding neutral isolation protection to components that may leak electricity after water enters the furnace. The heating unit 5 includes a heating element 502, a heating element bracket 501, and a neutral shield 503. The heating element 502 is mounted on the heating element bracket, and the neutral shield is located around the heating element. The neutral shield has ventilation holes and is connected to the neutral wire. The neutral shield is electrically isolated from easily accessible conductive parts of the composite air stove. The control unit also includes a neutral and live wire detection circuit for detecting whether the neutral and live wires are reversed. Figure 4 This is a schematic diagram of a heating unit with grounding isolation protection installed in a composite air cooker. Figure 5 This is a schematic diagram of this heating unit assembly. Figure 6 This is an exploded view of this type of heating unit. From Figure 5 and Figure 6As can be seen, the uninsulated parts of the heating element 502 and terminal 505 exposed in the inner furnace are completely enclosed in the zero-electrode cover 503. The zero-electrode cover has numerous mesh openings, allowing heat radiation from the heating element and air to pass through. In the diagram, the zero-electrode cover is divided into upper and lower parts, which together completely enclose the exposed live parts of the heating unit 5. The parts of the terminal not covered by the zero-electrode cover are insulated by the ceramic tube 504. The other end of the terminal is outside the outer furnace chamber 4. As long as the ceramic tube fits tightly with the terminal and the outer furnace chamber, there will be no water leakage, and no leakage protection is needed. Connecting the zero-electrode cover directly to the neutral wire of the heating unit is the best option, although this is not shown in the diagram. Its protection principle is: when the conductive liquid submerges the heating unit, the live wire of the heating unit conducts between the live wire and the zero-electrode cover. The voltage is entirely consumed by the resistance formed by the conductive liquid between the live wire and the zero-electrode cover. The voltage outside the zero-electrode cover is only a voltage drop across the neutral wire, typically only a few volts, thus providing protection as safe as good grounding. Figure 4As shown, the neutral wire shield maintains a certain distance from the fan blade shell and the conductive parts of the inner and outer furnace chambers, not less than the electrical clearance required by safety regulations. During normal operation, electrical safety isolation is achieved by air. In a normal circuit, the voltage drop across the neutral wire is very small, but considering the possibility of poor contact or disconnection, it is treated as a live wire. Household circuits or sockets may have the neutral and live wires reversed, so the control unit 10 also has a neutral and live wire identification circuit. If the neutral and live wires are reversed, the stove will sound an alarm or malfunction, and the user must correct the circuit to ensure the neutral wire shield is connected to neutral. With this heating unit structure, even if the inner and outer furnace chambers are completely filled with soup and all other protection functions fail, and the heating unit is still powered on, there will be no electric shock. Consider the following situations where the neutral wire may be energized: if the neutral wire is abnormally open, the stove will not function, and the heating unit will not be powered; if the neutral wire has poor contact, and its voltage drop is greater than 50 volts, the stove's maximum voltage is only 170 volts, and even lower in rural areas. Too low a voltage will also cause the control unit to malfunction, and the heating unit will not be powered. Therefore, this structure provides sufficient, even absolute, leakage protection regardless of any abnormality or reliance on a ground wire. Furthermore, the identification of the live and neutral wires is established upon first use, so a malfunction in the live and neutral wire identification circuit of the control unit has no impact. Of course, reversed live and neutral wire connections are a low-probability event. Considering the probabilities: the live and neutral wire identification circuit fails on first use; the live and neutral wires are reversed in the household circuit; the stove is filled with water while operating; there is no ground wire; the circuit breaker's leakage protection is malfunctioning; the liquid sensor is malfunctioning; the live and neutral wire identification and liquid sensor of control unit 10 are damaged but the heating function is normal; the user touches the stove directly with their hand while it is filled with water without disconnecting the power. The probability of all these events occurring simultaneously is almost zero. If any one of these issues is resolved, electric shock can be ensured, making it quite safe. The accompanying drawings of this application only show one structure utilizing grounding protection, but based on the grounding isolation concept of this embodiment, those skilled in the art can make various variations depending on the structure of the heating unit, the furnace structure, etc. For example, when the heating element bracket 501 is made of ceramic material and has no ventilation holes, and Figure 6 The zero-electrode cover 503 shown at the bottom is unnecessary; only the upper zero-electrode cover is required. When the area between the inner furnace chamber and the heating unit is made of insulating material, such as... Figure 7 As shown, the bottom of the inner furnace chamber is a glass plate 301, and the zero-pole cover 503 structure is completely unnecessary. Figure 5 Figure 6 The structure shown is as follows: Figure 7 As shown, only baffles of a certain height need to be installed on the inner and outer rings of the heating unit disc. With this structure, when the furnace chamber is filled with conductive liquid, one side of the glass plate 301 in the inner furnace chamber comes into contact with a 220V voltage. However, since the glass plate is not conductive, there is no safety hazard. Furthermore... Figure 1The conical heaters installed in the inner furnace can all be designed with reasonable grounding isolation protection based on the properties of the materials of the inner and outer furnace chambers.

[0045] In summary, the core idea of ​​the grounding isolation protection in this embodiment is as follows: the control unit must have neutral and live wire identification to ensure that grounding does not become live; a suitable neutral shield is set so that when the conductive liquid immerses the heating unit, all conductive parts of the stove that can be touched by the human body are at the same voltage as the neutral wire; sufficient insulation or electrical clearance must be maintained between the neutral shield and the conductive parts that can be touched by the human body; the neutral shield must not affect the heat transfer of the heating unit. All structures that can be easily conceived based on the above ideas are within the protection scope of this application.

[0046] The difference between this embodiment and Embodiment 1 is that the leakage protection under extreme conditions is further enhanced. Everything else is exactly the same as Embodiment 1. Unless there is a conflict, the structure and solution in Embodiment 1 can be adopted in this embodiment.

[0047] Example 3

[0048] Figures 1 to 3 The inner furnace chamber shown is made of an infrared-transmitting material such as high-temperature resistant glass, but the inner furnace chamber 3 can also be made of a material such as... Figure 4 , Figure 7 and Figure 10 The combined structure shown. (As shown in the example) Figure 4 As shown, the inner furnace chamber 3 includes a glass sheet 301 and a surrounding edge 302. A ventilation hole is formed in the center of the glass sheet. The glass sheet and the surrounding edge are assembled together to form an inner furnace chamber with the glass sheet as the bottom and the surrounding edge as the wall. The heating unit 5 is located below the glass sheet. This type of inner furnace chamber has a simpler manufacturing process and lower cost. It is made of microcrystalline glass. Figure 1 The bowl shape shown is larger than Figure 4 The glass flat plate shown is more complex.

[0049] Combination air cookers utilize air convection and thermal radiation for heating, and with controllable temperature, food can be placed directly in the inner chamber or on the burner opening for direct heating without relying on cookware. They can achieve some of the functions of an air fryer, oven, and grill. However... Figures 1 to 4 The internal furnace structure shown can perform functions such as simmering, baking, stewing, and grilling, but like the simmering and grilling functions of an electric ceramic stove, it has limitations. Figure 1 The inner furnace cone surface shown and Figure 4 The glass plate 301 shown relies on heat radiation to heat food, so it cannot be shielded. Grease, seasonings, and other contaminants will fall onto it, causing smoke and scorching, making smokeless grilling impossible and extremely difficult to clean. Excessive residue can also hinder heat radiation transmission. Electric ceramic stoves suffer from the same problem; while they can grill, they are not ideal due to the aforementioned drawbacks. Figure 10The diagram shows a relatively ideal structure for a barbecue-style combined air fryer. The inner furnace chamber 3 includes a glass tube 303 and a bottom cover 304. A ventilation hole is formed in the center of the bottom cover. The glass tube and bottom cover are assembled together to form the inner furnace chamber, with the bottom cover as the bottom and the glass tube as the wall. The heating unit is arranged around the glass tube. Both the heating unit and the glass tube for transmitting heat radiation are located on the side. In the diagram, the inclined surface extending from the furnace ring 18 acts like an eaves, shielding the glass tube 303 from rain, preventing food falling onto the side walls during grilling. During grilling, a drip tray 22 can be placed in the inner furnace chamber to collect any spilled oil, water, or other contaminants. Water can also be added to the drip tray 22 to completely prevent scorching and smoke from spilled grease, achieving smokeless grilling. After grilling, the drip tray can be removed, leaving the inside of the stove clean. Figure 10 The glass tube shown can also be replaced by multiple glass sheets assembled into a polyhedron, and such deformations are all within the protection scope of this application.

[0050] Figure 10 The structure shown, which places the heating unit 5 on the side, is only useful in this application when combined with a composite heating method of forced convection heating. If an electric ceramic stove only uses radiant heating, such a structure will result in very uneven heating of the cookware and make it unusable.

[0051] Where there is no conflict, the structures of the first two embodiments and this embodiment can be used in combination, and will not be described in detail here.

[0052] The above embodiments do not exhaust all structures and methods. All combinations of the above solutions, as well as any solutions that can be easily conceived through this utility model, are within the protection scope of this utility model.

Claims

1. A composite air cooker, comprising a shell, a heating unit (5), a control unit (10), a cooling fan (11), and a temperature sensing element (12), characterized in that: It also includes an outer furnace chamber (4), an inner furnace chamber (3), a motor (9), a fan blade (6), a fan blade shell (7), and a guide vane (8); the outer furnace chamber includes a cavity with one end open, made of heat-insulating material; the inner furnace chamber is a space for heating cookware; the inner furnace chamber includes an infrared transmission component; ventilation holes are provided at the bottom of the inner furnace chamber; the inner furnace chamber and the outer furnace chamber, after assembly, form a hollow interlayer that is connected vertically; the heating unit (5) is disposed in the hollow interlayer; the power terminal of the heating unit passes through the outer furnace chamber and is connected to the control unit; the temperature sensing element The temperature sensing element is connected to the control unit and is installed in the hollow sandwich or inner furnace chamber; the fan blade shell is used to constrain the airflow direction and is assembled on the inner or outer furnace chamber, or integrated with the inner or outer furnace chamber; the fan blade is installed in the fan blade shell, the shaft of the motor passes through the outer furnace chamber wall and is connected to the fan blade, and the motor is connected to the control unit; the air guide is installed at the air outlet of the fan blade or on the inner wall of the fan blade shell; the control unit (10) controls the working status of the heating unit and the motor according to the user settings or working conditions.

2. The composite air cooker according to claim 1, characterized in that: It also includes a liquid sensing device (13), which is installed at one or more locations in the inner furnace or the bottom of the hollow jacket. It uses changes in capacitance or resistance to sense whether liquid has entered the furnace. The liquid sensing device is connected to the control unit (10), and the control unit controls the working status of the heating unit (5) and the motor (9) according to the signal from the liquid sensing device.

3. A composite air cooker according to claim 1 or 2, characterized in that: The heating unit includes an electric heating element (502), a heating element bracket (501), and a neutral electrode cover (503); the electric heating element is mounted on the heating element bracket, the neutral electrode cover is disposed around the electric heating element, the neutral electrode cover is provided with ventilation holes, the neutral electrode cover is connected to the neutral wire, and the neutral electrode cover is electrically isolated from the easily accessible conductive parts of the composite air stove; the control unit also includes a neutral and live wire detection circuit for detecting whether the neutral and live wires are reversed.

4. A composite air cooker according to claim 1, characterized in that: It also includes a reflector (16), which is disposed in the inner furnace or the outer furnace to adjust the local radiation intensity.

5. A composite air cooker according to claim 1, characterized in that: It also includes a drain pipe (17) which is located at the bottom of the outer furnace chamber (4).

6. A composite air cooker according to claim 1, characterized in that: It also includes a pot inspection device, which includes a furnace ring (18), a switch (19), and a push rod (20); one end of the push rod is connected to the furnace ring, and the other end is connected to the switch. The switch is connected to the control unit, and the control unit controls the working status of the heating unit and the motor according to the switch signal.

7. A composite air cooker according to claim 1, characterized in that: The inner furnace chamber (3) includes a glass sheet (301) and a surrounding edge (302); a ventilation hole is opened in the center of the glass sheet, and the glass sheet and the surrounding edge are assembled together to form an inner furnace chamber with the glass sheet as the bottom and the surrounding edge as the wall, and the heating unit (5) is located below the glass sheet.

8. A composite air cooker according to claim 1, characterized in that: The inner furnace chamber (3) includes a glass tube (303) and a bottom cover (304); the bottom cover has a ventilation hole in the center, and the glass tube and the bottom cover are assembled together to form an inner furnace chamber with the bottom cover as the bottom and the glass tube as the wall, and the heating unit is arranged around the glass tube.

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