Bladeless fan and air frying furnace end

Abstract

The utility model provides a bladeless fan and an air fryer end, and aims to solve the problems that a hot air fan used on the air fryer end in the prior art is unreasonable in design, insufficient in air inlet flow, low in air outlet pressure and incapable of providing enough air for a cooking cavity, so that the cooking efficiency is low. A bladeless fan comprises a shell, a fan air outlet is formed in the circumferential direction of the upper portion of the shell, and a fan air inlet is formed in the middle of the lower portion of the shell. The inclined air duct is communicated with the fan air inlet and the fan air outlet, and the inclined air duct extends from bottom to top and inclines from the middle to the periphery; and the blades are arranged in the inclined air duct in the circumferential direction of the inclined air duct, and the height of each blade is gradually decreased from the middle of the inclined air duct to the periphery of the inclined air duct. According to the utility model, the output high-pressure air flow can overcome the resistance of the downstream pipeline, the filter screen and the cavity, so that the air with enough volume can be conveyed into a target cavity.

Description

Technical Field

[0001] This utility model belongs to the field of air fryer head technology, specifically relating to a bladeless fan and an air fryer head. Background Technology

[0002] When an air fryer is working, a motor inside the air fryer head drives a hot air fan. The hot air fan blows the heat emitted by the heating element into the cooking cavity as hot air, thus heating the food inside. However, the hot air fan structure used in existing air fryer heads is poorly designed, mainly due to the following problems:

[0003] 1. Insufficient central air intake: The small air intake cross-sectional area in the center of the fan creates a low-pressure vortex zone, resulting in insufficient air intake flow.

[0004] 2. Inappropriate blade design: When the motor drives the hot air fan to rotate, the motor's mechanical energy cannot be effectively converted into the kinetic and pressure energy of the air. The air pressure blown out from the fan outlet is low, resulting in low air pressure. This makes it impossible to provide enough air into the cooking cavity, which in turn leads to low heating efficiency.

[0005] Because of the aforementioned problems with the heating fan in existing air fryers, improvements to the existing heating fan are necessary. Utility Model Content

[0006] This invention provides a bladeless fan and an air fryer head, aiming to solve the problems of unreasonable design of the hot fan used in the existing air fryer head, which has insufficient air intake flow, low air pressure and inability to provide enough air into the cooking cavity, resulting in low cooking efficiency.

[0007] To solve the above-mentioned technical problems, the technical solution adopted by this utility model is as follows:

[0008] In a first aspect, this utility model provides a bladeless fan, comprising:

[0009] The housing has a fan outlet circumferentially arranged around the upper part of the housing, and a fan inlet is arranged in the middle of the lower part of the housing;

[0010] An inclined air duct connects the fan inlet and the fan outlet. The inclined air duct extends from bottom to top and slopes from the center to the periphery. The upper side of the inclined air duct has an upper top wall, and the lower side has a lower bottom wall. The upper side of the inclined air duct is defined by the upper top wall, and the lower side is defined by the lower bottom wall. The distance between the upper top wall and the lower bottom wall gradually decreases from the center to the periphery.

[0011] Several blades are evenly distributed around the inclined air duct in the circumference of the inclined air duct. The upper end of each blade is connected to the upper top wall of the housing, and the lower end of each blade is connected to the lower bottom wall of the housing. The height of each blade gradually decreases from the middle to the outer edge of the inclined air duct. The several blades divide the inclined air duct into several sub-inclined air ducts, and the several blades divide the fan outlet into several sub-fan outlets.

[0012] A further embodiment: The bottom wall of the housing extends in a funnel shape from the fan inlet to the fan outlet.

[0013] Based on the above technical solution: the horn-shaped structure enables the inclined air duct and blades to guide the airflow to accelerate smoothly, reduce flow separation losses, and at the same time enhance the radial pushing effect of centrifugal force on the airflow, further increasing energy conversion efficiency, so that the mechanical energy output by the motor to the fan can be more efficiently converted into the pressure energy of the output air.

[0014] A further embodiment: each blade is arc-shaped, and the protrusion direction of several arc-shaped blades all points clockwise or all points counterclockwise.

[0015] Based on the above technical solution: the arc-shaped extended blades can form a continuous guide surface, making the contraction-acceleration flow channel more effective. The arc-shaped extended blades can also guide the airflow direction and effectively utilize the centrifugal force when the fan rotates to make the airflow flow out at the designed angle (usually the combined direction of radial and tangential). At the same time, the lift generated by the arc-shaped blade shape also helps to push the airflow and increase its energy, reducing flow separation and friction loss.

[0016] A further embodiment: the axial direction of the fan inlet is perpendicular to the radial direction of the fan outlet.

[0017] Based on the above technical solution: the vertical layout can adapt to the compact space of the air fryer head, so that the airflow is drawn upward from the bottom fan inlet, and then the airflow is turned to blow out circumferentially from the top fan outlet.

[0018] A further embodiment: the upper end of each blade is integrally formed with the upper top wall of the housing; the lower end of each blade is integrally formed with the lower bottom wall of the housing.

[0019] Based on the above technical solution: the one-piece molding design can increase the mechanical stability of the structure and avoid deformation caused by high-speed rotation.

[0020] A further option: the top wall of the shell is a circular plate.

[0021] A further option: the diameter of the fan inlet is 13.5mm to 23.5mm.

[0022] A further option: the height of the fan outlet is 5mm to 15mm.

[0023] A further option: the number of blades is 7 to 13.

[0024] Secondly, this utility model provides an air fryer head, comprising:

[0025] Stove head casing;

[0026] A bladeless fan as described in any of the solutions in the first aspect;

[0027] A bladeless fan cover is disposed inside the furnace head housing, and the bladeless fan cover is disposed on the upper side of the bladeless fan and covers the bladeless fan;

[0028] The hot air shroud is located on the lower side of the bladeless fan shroud and is sealed to the bladeless fan shroud.

[0029] An air guide section is located on the lower side of the bladeless fan. The air guide section and the inner wall of the bladeless fan cover form an air outlet channel for connecting the fan outlet and the cooking cavity. A ventilation hole is provided in the middle of the air guide section for connecting the fan inlet and the cooking cavity.

[0030] The heating element is suspended below the hot air shroud; and,

[0031] The motor is located on the upper side of the bladeless fan housing and is connected to drive the bladeless fan.

[0032] Based on the above technical solution: by placing the air guide below the bladeless fan and forming an air outlet channel between it and the inner wall of the bladeless fan housing, the air blown from the bladeless fan's outlet enters the cooking chamber through the annular air outlet channel, ensuring full contact with the food and thus more even heating. The bladeless fan draws air from the top of the cooking chamber through ventilation holes and a fan inlet, creating a circulation path of hot air between the cooking chamber and the bladeless fan. The hot air heats the food within the cooking chamber along this circulation path, resulting in more efficient cooking. The bladeless fan housing and the hot air cover are sealed together, ensuring better airtightness.

[0033] A further embodiment: The air guide includes:

[0034] A parallel extension is located on the lower side of the lower bottom wall of the housing and is arranged parallel to the lower bottom wall of the housing; and...

[0035] The airflow guide is located at the outer edge of the parallel extension and extends gradually downward from the inside out; the airflow guide and the inner sidewall of the bladeless fan cover form the air outlet channel.

[0036] Based on the above technical solution: the parallel extension is arranged parallel to the bottom wall of the housing, allowing the air blown from the fan outlet to smoothly enter the cooking cavity through the air outlet channel, avoiding turbulence caused by mutual interference between the fan outlet and the fan inlet, and making the airflow field more stable. An annular air outlet channel is formed between the air guide and the inner wall of the bladeless fan housing, thus creating an annular air curtain facing the cooking cavity, further improving the uniformity of heating.

[0037] A further solution: the width of the air outlet channel gradually decreases from the air inlet end to the air outlet end.

[0038] Based on the above technical solution: the tapered air outlet channel can play a secondary pressurization role, so that the airflow is accelerated and pressurized again after flowing out of the fan outlet, further increasing the air pressure of the airflow flowing out from the air outlet end of the air outlet channel, thereby forming a negative pressure on the inner and outer sides of the air outlet end of the air outlet channel, so that the airflow can fully absorb the heat around the heating tube and participate in the hot air circulation.

[0039] A further solution: The outer end of the guide section is provided with several connecting parts, one end of each connecting part is connected to the guide section, and the other end of each connecting part is connected to the hot air hood. The several connecting parts divide the air outlet end of the air outlet channel into several channel air outlets.

[0040] Based on the above technical solution: the above configuration facilitates the connection between the air guide and the hot air cover, thereby suspending it under the bladeless fan.

[0041] A further embodiment: the heating element includes a first heating element located on the inner side and a second heating element located on the outer side of the first heating element, and the air outlet end of the air outlet channel faces between the first heating element and the second heating element.

[0042] Based on the above technical solution: the air outlet end of the air outlet channel faces the middle of the first heating element and the second heating element. Due to the high air pressure at the air outlet end of the air outlet channel, a negative pressure is formed on both the inner and outer sides of the air outlet end of the air outlet channel. This can draw away the hot air near the first heating element and the second heating element, so that the heat emitted by the heating element can participate more fully in the hot air circulation. It can also avoid the problem of heat accumulating near the heating element, which would cause the burner head temperature to be too high.

[0043] A further embodiment: the width of the air outlet channel at its air outlet end is 1.5mm to 5.5mm.

[0044] The beneficial effects of this utility model are as follows:

[0045] 1. This utility model features a fan outlet circumferentially located at the top of the housing and a fan inlet located in the center of the bottom of the housing, creating a structural layout where air enters from the bottom center and exits circumferentially from the top. By designing the distance between the top wall and bottom wall of the housing to gradually decrease from the center to the periphery, and by gradually decreasing the height of each blade from the center to the periphery of the inclined air duct, blades that are thicker in the center and thinner at the edges are formed. This design, combining thicker blades with thinner edges and an inclined air duct, creates a contraction-acceleration flow channel. The bladeless fan draws air in from the central fan inlet and compresses it at the outer fan outlet, increasing the air pressure and facilitating the supply of sufficient air into the cavity.

[0046] Furthermore, the centrifugal force generated by the rotation of a bladeless fan increases the mechanical energy of the air, effectively converting high-speed airflow into high-pressure airflow, creating a high-pressure airflow at the fan outlet. This high-pressure air overcomes the resistance of downstream pipes, filters, and the cavity itself, allowing sufficient volume of air to be delivered to the target cavity. When used as a heating fan in an air fryer, it delivers a sufficient volume of air into the cooking cavity, resulting in greater heat exchange with the food and improved cooking efficiency.

[0047] 2. This invention designs the blades with a thicker center and thinner periphery because the linear velocity is lower in the central region of blade rotation (near the blade root). To ensure sufficient air intake even in this low-velocity region, the blade height at this location needs to be increased, thereby increasing the effective airflow cross-sectional area. This avoids the problem of insufficient air intake in the central region due to low linear velocity and small cross-sectional area. Furthermore, the larger central intake area allows air to enter the inclined duct more smoothly and at a relatively lower velocity, reducing impact losses and intake vortices between the airflow and the blade leading edge, thus improving intake efficiency and resulting in higher exhaust air pressure. Attached Figure Description

[0048] To more clearly illustrate the technical solutions of the embodiments of this utility model, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this utility model and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0049] Figure 1 This is a schematic diagram of the structure of a bladeless fan according to this utility model.

[0050] Figure 2 This is a schematic cross-sectional view of a bladeless fan according to the present invention in the first direction.

[0051] Figure 3This is a cross-sectional view of the bladeless fan of this utility model from a second direction.

[0052] Figure 4 This is a cross-sectional structural diagram of an air fryer head according to the present invention.

[0053] Figure 5 yes Figure 4 A magnified structural diagram at point A.

[0054] Figure 6 This is a schematic diagram of the structure connecting the air guide section and the hot air hood.

[0055] Figure 7 This is a structural schematic diagram from the bottom of the air fryer head.

[0056] Explanation of the labels in the diagram:

[0057] 1-Shell; 11-Top wall of the shell; 12-Bottom wall of the shell; 13-Inclined air duct; 14-Blade; 15-Fan air inlet; 16-Fan air outlet; 2-Hot air cover; 21-Bladeless fan cover; 22-Suspension device; 23-Sealing ring; 3-Motor cover; 31-Cooling fan; 32-Motor; 4-Air guide; 41-Parallel extension; 42-Flow guide; 43-Ventilation hole; 44-Connecting part; 5-Heating element; 51-First heating element; 52-Second heating element; 6-Air outlet channel; 61-Channel air outlet. Detailed Implementation

[0058] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. It should be understood that the specific embodiments described herein are merely for explaining the present utility model and are not intended to limit the present utility model. All other embodiments obtained by those skilled in the art based on the embodiments of the present utility model without creative effort are within the protection scope of the present utility model.

[0059] Example 1:

[0060] like Figures 1 to 3 As shown, this embodiment provides a bladeless fan, including:

[0061] The housing 1 has a fan outlet 16 circumferentially arranged around the upper part of the housing 1, and a fan inlet 15 is arranged in the middle of the lower part of the housing 1.

[0062] An inclined air duct 13 connects the fan inlet 15 and the fan outlet 16. The inclined air duct 13 extends from bottom to top and from the center to the periphery, with the periphery being the outer edge along the radial direction. The upper side of the inclined air duct 13 is provided with an upper top wall 11 of the housing, and the lower side of the inclined air duct 13 is provided with a lower bottom wall 12 of the housing. The upper side of the inclined air duct 13 is defined by the upper top wall 11 of the housing, and the lower side is defined by the lower bottom wall 12 of the housing. The distance between the upper top wall 11 and the lower bottom wall 12 of the housing gradually decreases from the center to the periphery.

[0063] Several blades 14 are evenly distributed around the inclined air duct 13. The upper end of each blade 14 is connected to the upper top wall 11 of the housing, and the lower end of each blade 14 is connected to the lower bottom wall 12 of the housing. The height of each blade 14 gradually decreases from the middle to the outer edge of the inclined air duct 13. The several blades 14 divide the inclined air duct 13 into several sub-inclined air ducts 13, and the several blades 14 divide the fan outlet 16 into several sub-fan outlets 16.

[0064] In some specific implementations, such as Figures 1 to 3 As shown, the lower bottom wall 12 of the housing extends in a funnel shape from the fan inlet 15 to the fan outlet 16, thereby making the transition of the inclined air duct 13 from the fan inlet 15 to the fan outlet 16 smoother. When the airflow flows from the fan inlet 15 to the fan outlet 16, the funnel-shaped structure allows the inclined air duct 13 to guide the airflow to accelerate smoothly.

[0065] The top wall 11 of the shell is preferably circular. This allows the top wall 11 to be positioned closer to the top wall of the hot air hood 2 when it is located inside the air fryer head, which not only provides pressurization but also reduces the space it occupies.

[0066] In some specific implementations, such as Figures 1 to 3 As shown, each blade 14 is arc-shaped, and the protruding direction of several arc-shaped blades 14 all points clockwise or all points counterclockwise. Specifically, the arc-shaped structure or arc angle of the blades 14 can be set according to the rotation direction of the motor 32 or the actual application. The arc-shaped extended blades 14 can form a continuous guide surface, thereby guiding the airflow direction, so that the airflow flows out at the designed angle (usually the combined direction of radial and tangential) under the action of centrifugal force when the fan rotates.

[0067] In some specific embodiments, the axial direction of the fan inlet 15 is perpendicular to the radial direction of the fan outlet 16. That is, the air outlet direction of the fan outlet 16 is spatially perpendicular to the axis of the fan inlet 15. This causes airflow to be drawn upward from the bottom fan inlet 15, and then the airflow is redirected to be blown out circumferentially from the upper fan outlet 16. When used on an air fryer head, the airflow enters the cooking chamber from the fan outlet 16, and then flows back from the cooking chamber to the fan inlet 15, thus forming a predetermined airflow circulation path.

[0068] In some specific implementations, such as Figures 1 to 3 As shown, the upper end of each blade 14 is preferably integrally formed with the upper top wall 11 of the housing; the lower end of each blade 14 is preferably integrally formed with the lower bottom wall 12 of the housing. The integral forming configuration can increase the mechanical stability of the structure and avoid deformation of the blade 14 caused by high-speed rotation.

[0069] In some specific implementations, such as Figures 1 to 3 As shown, the preferred diameter of the fan inlet 15 is 13.5mm to 23.5mm. The relationship between the diameter of the fan inlet 15 and the average airflow velocity in the cavity (which can be a cooking cavity) is shown in Table 1. As can be seen from Table 1, increasing the diameter of the fan inlet 15, i.e. increasing the air intake cross-sectional area, can increase the average airflow velocity in the cavity. The diameter of the fan inlet 15 can be set according to actual needs.

[0070] Table 1

[0071] Fan inlet diameter d 13.5mm 18.5mm 23.5mm Average airflow velocity within the cavity 2.75m / s 2.89m / s 2.98m / s

[0072] In some specific implementations, such as Figures 1 to 3 As shown, the preferred height of the fan outlet 16 is 5mm to 15mm. The relationship between the diameter of the fan outlet 16 and the average airflow velocity within the cavity (which can be a cooking cavity) is shown in Table 2. Table 2 shows that as the diameter of the fan outlet 16 increases, the average airflow velocity within the cavity first increases and then decreases. The diameter of the fan outlet 16 can be set according to actual needs.

[0073] Table 2

[0074] Fan outlet height h 5mm 7mm 10mm 12mm 15mm Average airflow velocity within the cavity 2.9m / s 3.1m / s 3.5m / s 4.2m / s 3.6m / s

[0075] In some specific implementations, such as Figures 1 to 3As shown, the number of blades 14 is preferably 7 to 13. Table 3 shows the relationship between the number of blades 14 and the average airflow velocity within the cavity (which can be a cooking cavity). Table 3 shows that as the number of blades 14 increases, the average airflow velocity within the cavity first increases and then decreases, reaching its maximum when the number of blades 14 is 11. The number of blades 14 can be set according to actual needs.

[0076] Table 3

[0077] Number of leaves 7 9 11 13 Average airflow velocity within the cavity 3.2m / s 4.5m / s 4.9m / s 3.4m / s Example

[0078] like Figures 1 to 7 As shown, this embodiment provides an air fryer head, including:

[0079] Stove head shell 1;

[0080] A bladeless fan as described in any of the embodiments in Example 1; and,

[0081] A bladeless fan cover 21 is disposed inside the burner head housing 1, and the bladeless fan cover 21 covers the upper side of the bladeless fan and covers the bladeless fan.

[0082] The hot air cover 2 is located on the lower side of the bladeless fan cover 21 and is sealed to the bladeless fan cover 21.

[0083] The air guide section 4 is located on the lower side of the bladeless fan. The air guide section 4 and the inner side wall of the bladeless fan cover 21 form an air outlet channel 6 for connecting the fan air outlet 16 and the cooking cavity. The middle part of the air guide section 4 is provided with a ventilation hole 43 for connecting the fan air inlet 15 and the cooking cavity. The air guide section 4 can be specifically configured to be integrally formed with the hot air cover 2 or fixedly connected.

[0084] The heating element 5 is suspended on the lower side of the hot air hood 2, and preferably located on the lower side of the air guide 4; specifically, it can be suspended on the hot air hood 2 by a suspension device 22. The suspension device 22 is widely used in existing technology and will not be described in detail in this embodiment; and,

[0085] Motor 32 is located on the upper side of the bladeless fan housing 21 and is connected to drive the bladeless fan. The output shaft of motor 32 passes through the bladeless fan housing 21 and is fixedly connected to the top wall 11 of the bladeless fan housing.

[0086] Specifically, the air blown out of the bladeless fan outlet 16 enters the cooking chamber on the lower side through the annular air outlet 6, and then flows back to the fan inlet 15 of the bladeless fan through the ventilation hole 43, thus forming a hot air circulation path, which can cook food more efficiently.

[0087] The upper side of the bladeless fan cover 21 is also provided with a motor cover 3. The motor cover 3, the bladeless fan cover 21, and the hot air cover 2 form a cooling fan 31 mounting cavity. The cooling fan 31 is provided in the cooling fan 31 mounting cavity. The motor 32 is fixed on the motor cover 3, and the cooling fan 31 and the bladeless fan are coaxially arranged.

[0088] The air guide 4 includes:

[0089] The parallel extension 41 is located on the lower side of the lower bottom wall 12 of the housing and is arranged parallel to the lower bottom wall 12 of the housing; and,

[0090] The airflow guide 42 is located on the outer edge of the parallel extension 41, and the airflow guide 42 extends from the inside out and gradually downwards; the airflow guide 42 and the inner sidewall of the bladeless fan cover 21 form the air outlet channel 6.

[0091] The air outlet channel 6 is tapered in width, meaning its width gradually decreases from the air inlet to the air outlet. Specifically, the distance between the guide section 42 and the inner wall of the bladeless fan housing 21 gradually decreases along the airflow direction, thereby providing a secondary pressurization effect.

[0092] In some specific embodiments, the lower outer edge of the bladeless fan housing 21 is folded outward to form an annular connecting portion, thereby facilitating connection with the hot air shroud 2. A sealing ring 23 is provided between the annular connecting portion and the hot air shroud 2, thereby ensuring a sealed connection between the bladeless fan housing 21 and the hot air shroud 2. The bladeless fan housing 21 specifically includes an upper top wall and an inner side wall extending downward around the upper top wall.

[0093] In some specific implementations, such as Figure 6 and Figure 7 As shown, a plurality of connecting portions 44 are provided around the outer end of the air guide portion 42. One end of each connecting portion 44 is connected to the air guide portion 42, and the other end of each connecting portion 44 is connected to the hot air hood 2. The plurality of connecting portions 44 divide the air outlet end of the air outlet channel 6 into a plurality of arc-shaped channel air outlets 61. The connecting portion 44 is specifically a connecting piece or a connecting rib. Furthermore, the connecting portion 44, the air guide portion 4, and the hot air hood 2 are integrally formed.

[0094] The heating element 5 includes a first heating element 51 located on the inner side and a second heating element 52 located on the outer side of the first heating element 51. The air outlet end of the air outlet channel 6 faces between the first heating element 51 and the second heating element 52. The first heating element 51 and the second heating element 52 are integrally formed, and the second heating element 52 surrounds the outer side of the first heating element 51. With the air outlet end of the air outlet channel 6 facing the middle of the first heating element 51 and the second heating element 52, due to the high air pressure at the air outlet end of the air outlet channel 6, a negative pressure is formed on both the inner and outer sides of the air outlet end of the air outlet channel 6, i.e., around the heating element 5. This allows the high-pressure airflow to draw away the hot air near the first heating element 51 and the second heating element 52 and participate in the hot air circulation, thus avoiding the problem of heat accumulation near the heating element 5 and causing the burner head temperature to be too high.

[0095] In some specific implementations, such as Figures 4 to 7 As shown, the upper top wall 11 of the housing is located near the upper top wall of the bladeless fan cover 21, and the parallel extension 41 is located near the lower bottom wall 12 of the housing, thereby forming a sealed pressurization chamber to prevent high-pressure airflow from flowing back, thus improving the static pressure output stability of the bladeless fan.

[0096] In some specific embodiments, in order to further ensure that the airflow in the cooking cavity flows back evenly to the fan inlet 15 of the bladeless fan, the axis of the ventilation hole 43 coincides with the axis of the fan inlet 15, and the diameter of the ventilation hole 43 is larger than the diameter of the fan inlet 15.

[0097] In some specific implementations, such as Figures 4 to 7 As shown, the width of the air outlet channel 6 at its outlet end ranges from 1.5mm to 5.5mm. The relationship between the width of the outlet end and the average airflow velocity within the cavity is shown in Table 4. As the width of the outlet end increases, the average airflow velocity within the cavity first increases and then decreases, reaching its maximum when the outlet end width is 3.5mm. The width of the outlet end can be set according to specific requirements.

[0098] Table 4

[0099] Air outlet width w 1.5mm 3.5mm 5.5mm Average airflow velocity within the cavity 2.9m / s 4.4 m / s 3.1m / s

[0100] Working principle explanation:

[0101] First, leaf 14 is thicker in the middle and thinner on the outer side;

[0102] Design objective: To increase the intake cross-sectional area and optimize the intake flow distribution.

[0103] Working principle: According to the continuity equation: Q=A*V (flow rate = cross-sectional area * average velocity), it can be seen that the linear velocity is relatively low in the central region of blade 14 (near the blade root) (V=ω*r, where ω is the angular velocity and r is the radius). In order to draw in enough air even in the low linear velocity region (ensuring the total flow rate Q), the height of blade 14 at this location needs to be increased, thereby increasing the effective flow cross-sectional area A. This avoids the central region becoming an intake bottleneck due to low linear velocity and small cross-sectional area.

[0104] Effects: Reduced intake resistance / impact loss; the larger central intake area allows air to enter the inclined air duct 13 more smoothly and at a relatively low speed, reducing the impact loss of airflow with the leading edge of the blades 14 and the intake vortex, thus improving intake efficiency.

[0105] Second, the synergistic design of thick in the middle and thin on the outside (thickness variation of blade 14) + inclined air duct 13 (shape of blade 14 / inclination of air duct);

[0106] Design purpose: To form a contraction-acceleration flow channel to guide the airflow direction and use the centrifugal force of the bladeless fan during rotation to increase the air pressure.

[0107] Working Principle: Airflow moves from the root (thicker in the middle) of blade 14 to the tip (thinner on the outside), and the flow channel formed between blades 14 is constricted (cross-sectional area decreases). According to the continuity equation (Q=A*V=constant), the decrease in the cross-sectional area A of the flow channel inevitably leads to an increase in the flow velocity V. Centrifugal Force Work: When air flows inside the rotating fan, it is subjected to a strong centrifugal force, which points from the center of rotation to the outer edge. Blades 14 force the air to move outward along the inclined flow channel. In this process, the centrifugal force does positive work on the airflow, thereby increasing the mechanical energy (mainly kinetic and pressure energy) of the air, and thus increasing the pressure of the airflow discharged from the fan. In addition, the inclined blades 14 (forming the inclined air duct 13) not only provide the flow channel boundary, but more importantly, guide the direction of the airflow. The inclined blades 14 force the airflow to flow out at the designed angle (usually the combined direction of radial and tangential directions), and the lift generated by the shape of blades 14 also helps to propel the airflow and increase its energy, thus increasing the pressure of the airflow discharged from the fan.

[0108] Third, the gradually narrowing air outlet channel 6;

[0109] When the high-pressure airflow blown out of the fan outlet 16 passes through the tapered air outlet channel 6, it undergoes secondary pressurization, thereby blowing a sufficient amount of air into the cooking cavity, which can heat the food more thoroughly and improve heating efficiency.

[0110] This utility model is not limited to the above-mentioned optional embodiments. Under the premise of non-contradiction, the various solutions can be combined arbitrarily. Anyone can derive other forms of products under the guidance of this utility model. However, no matter what changes are made in their shape or structure, all technical solutions that fall within the scope of the claims of this utility model are within the protection scope of this utility model.

Claims

1. A bladeless fan, characterized by, Comprising: a housing, a fan outlet being provided around the circumference of the upper part of the housing, a fan inlet being provided in the middle of the lower part of the housing; an inclined air duct, communicating the fan inlet and the fan outlet, the extension direction of the inclined air duct being inclined from lower to upper and from middle to periphery; the upper side of the inclined air duct being provided with a housing upper top wall, the lower side of the inclined air duct being provided with a housing lower bottom wall, the upper side of the inclined air duct being defined by the housing upper top wall, the lower side of the inclined air duct being defined by the housing lower bottom wall, and the spacing between the housing upper top wall and the housing lower bottom wall gradually decreasing from middle to periphery; and, a plurality of blades, being uniformly distributed in the inclined air duct around the circumference of the inclined air duct, the upper end of each blade being connected with the housing upper top wall, the lower end of each blade being connected with the housing lower bottom wall, and the height of each blade gradually decreasing from middle to periphery of the inclined air duct; the plurality of blades dividing the inclined air duct into a plurality of sub-inclined air ducts, and the plurality of blades dividing the fan outlet into a plurality of sub-fan outlets.

2. A bladeless fan as claimed in claim 1, wherein, The housing lower bottom wall extends in a trumpet shape from the fan inlet to the fan outlet.

3. A bladeless fan as claimed in claim 1, wherein, Each of the blades is arc-shaped, and the convex directions of the plurality of arc-shaped blades all point to the clockwise direction or all point to the counterclockwise direction.

4. A bladeless fan as described in claim 1, wherein, The axis direction of the fan inlet is perpendicular to the outlet radial space of the fan outlet.

5. A bladeless fan as described in claim 1, wherein, The upper end of each blade is integrally formed with the housing upper top wall; the lower end of each blade is integrally formed with the housing lower bottom wall.

6. A bladeless fan as described in claim 1, wherein, The housing upper top wall is a circular plate.

7. A bladeless fan as described in claim 1, wherein, The diameter of the fan inlet is 13.5mm-23.5mm.

8. A bladeless fan as described in claim 1, wherein, The height of the fan outlet is 5mm-15mm.

9. A bladeless fan as described in claim 1, wherein, The number of the blades is 7-13.

10. An air fryer head, characterized in that, Comprising: a burner housing; a bladeless fan as claimed in any one of claims 1 to 9; a bladeless fan cover, being provided in the burner housing, covering the upper side of the bladeless fan; a hot air cover, being located at the lower side of the bladeless fan cover and being sealingly connected with the bladeless fan cover; an air guide part, being located at the lower side of the bladeless fan, the air guide part and the inner side wall of the bladeless fan cover surrounding an outlet passage for communicating the fan outlet and the cooking cavity; the middle part of the air guide part being provided with a ventilation hole for communicating the fan inlet and the cooking cavity; a heating tube, being suspended at the lower side of the hot air cover; and a motor, being located at the upper side of the bladeless fan cover and drivingly connected with the bladeless fan.

11. A stovetop pizza oven head as claimed in claim 10, characterized in that, The air guide part comprises: a parallel extension part, being located at the lower side of the housing lower bottom wall and being provided in parallel with the housing lower bottom wall; and a flow guide part, being located at the outer edge of the parallel extension part and gradually extending from inside to outside and downward; the flow guide part and the inner side wall of the bladeless fan cover surrounding the outlet passage.

12. A stovetop air fryer head as claimed in claim 10 or 11, wherein, The width of the outlet passage gradually decreases from the inlet end of the outlet passage to the outlet end of the outlet passage.

13. The air fryer head of claim 11, wherein, A plurality of connecting portions are arranged around the outer end of the flow guide portion, one end of each of the connecting portions is connected to the flow guide portion, the other end of each of the connecting portions is connected to the hot air cover, and the plurality of connecting portions divide the air outlet end of the air outlet channel into a plurality of channel air outlet openings.

14. The air fryer head of claim 10, wherein, The heating tube comprises a first heating tube located at the inner side and a second heating tube located at the outer side of the first heating tube, and the air outlet end of the air outlet channel faces between the first heating tube and the second heating tube.

15. The air fryer head of claim 10, wherein, The width of the air outlet end of the air outlet channel is 1.5mm-5.5mm.

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