An induction HOB with a diffuser plate

Abstract

The invention relates to an induction hob comprising a housing (10) with a ventilation opening (14); an induction first heating element (20) and a second heating element (40) mounted spaced apart within the housing (10); at least one fan (50) arranged to convey the cooling air it produces by accelerating the ambient air supplied from the ventilation opening (14) via a first air flow path (f1) directed towards the first heating element (20) and at least one second air flow path (f2) directed towards the second heating element (40). The induction hob has a diffuser element (70) has a base plate (74) over which the cooling air progressing in the second air flow path (f2) received via an inlet (72) is carried and which extends at least partially under the second heating element (40), and at least one fin (a-e) on the base plate (74) that directs the cooling air supplied from the inlet (72) to radially expand over the base plate (74).

Description

[0001] AN INDUCTION HOB WITH A DIFFUSER PLATE

[0002] TECHNICAL FIELD

[0003] The present invention relates to an induction hob wherein the cooling system includes a fan, particularly to an induction hob in which the air conveyed by the fan passes through an air flow corridor to be delivered to an induction heating element.

[0004] STATE OF THE ART

[0005] In induction hobs, there are coil elements mounted spaced apart on a carrier element. A cooling fan is used to provide direct air flow to the coils and IGBT elements, as with other electronic components. The cooling fan accelerates the ambient air it takes from the outside and usually passes it through a heat sink. Due to the geometry of the heat sink, the cooling air is not evenly distributed to the outlet parts. Therefore, the cooling air is not evenly distributed in the coils; while successful cooling is provided in some ferrite materials located under the coil, high temperatures occur in some areas due to the inability to provide equal distribution. This negatively affects the efficiency and lifespan of the hob.

[0006] WO2021112776 describes an induction hob with a cooling system. The induction hob includes a housing; an induction element connected to an electronic device located at a base of the housing; and a magnetically permeable planar upper plate covering the housing in a way that limits an air channel with a predetermined channel height within a magnetic field distance that provides the cooking effect between the induction element and the upper plate. Additionally, an axial fan is located at the base of the housing, which, when energized, is arranged to distribute the air flow path created in the air channel towards the induction element by directly striking the upper plate from a lower wall due to its rotational speed.

[0007] BRIEF DESCRIPTION OF THE INVENTION

[0008] The object of the invention is to increase the cooling efficiency of the heating element in an induction hob where ambient air is drawn in, pressurized with a fan, and delivered to a distant heating element. To achieve the aforementioned objective, the invention relates to an induction hob comprising a housing with a ventilation opening; an induction first heating element and a second heating element mounted spaced apart within the housing; at least one fan arranged to convey the cooling air it produces by accelerating the ambient air supplied from the ventilation opening via a first air flow path directed towards the first heating element and at least one second air flow path directed towards the second heating element. The induction hob has a diffuser element including a base plate over which the cooling air progressing in the second air flow path received via an inlet is carried and which extends at least partially under the second heating element, and at least one fin on the base plate that directs the cooling air supplied from the inlet to radially expand over the base plate. The fin helps to evenly distribute the cooling air under the second heating element. Surprisingly, it has been found that the use of fins in the air corridor between the base plate and the second heating element eliminates vortex formation that reduces the energy of the cooling air, thereby increasing cooling efficiency.

[0009] Preferably, multiple fins in the diffuser element are arranged adjacent to each other to form expanding channels from the narrow part facing the inlet. The expanding guiding channels reduce the resistance of the cooling air, allowing the fan to operate more efficiently. This reduces energy consumption and offers a cooling system that requires lower power.

[0010] Preferably, the fins are in a triangular-like geometric form erected from one edge on the base plate. This form provides rapid evacuation of the cooling air from the corridor formed between the fins and helps direct the air upward toward the second heating element.

[0011] Preferably, the fins include a front wall extending parallel to the second air flow path. In this way, the cooling air at the inlet is entirely directed to the inlet without significant pressure loss and then distributed at an angle over the base plate.

[0012] Preferably, the deviation angle of the fins relative to the second air flow path is adjusted to increase from end to end. In this way, the channel outlets expand and open, making it possible to cool the second heating element with fewer fins.

[0013] Preferably, the deviation angle of the fins relative to the second air flow path is adjusted between 10-60 degrees. It has been found that the mentioned angle ranges help to make the cooling air flow profile laminar and eliminate vortices. Preferably, the induction hob includes a heat sink with cooling walls extending transversely parallel to each other through which the second air flow path passes between corresponding ends where the fins engage. In this case, the cooling air coming to the fins is directed in the direction of the second air flow path by the heat sink channels before the inlet.

[0014] Preferably, the induction hob includes a second heating element comprising a frame containing ferrite and a second coil wound on the frame. In this way, a second induction heating element is obtained and cooled by the cooling air conveyed by the fan during or after operation.

[0015] Preferably, the diffuser element includes a peripheral edge provided on the periphery of the base plate in a way that limits the inlet. The peripheral edge allows the cooling air taken from the inlet to be circumferentially limited and ensures that all of the cooling air is used in cooling the second heating element.

[0016] Preferably, the fan is a single axial fan, and the ventilation opening is provided on the base plate of the housing so that it remains under the air inlet of the axial fan, and includes a deflector plate adapted to the fan housing to form the second air flow path in the radial direction of the axial fan. In this way, it becomes possible to cool both the first heating element and the second heating element with a single fan.

[0017] Preferably, the diffuser element includes a protrusion provided adjacent to the inlet portion, which deflects the second air flow path upward toward the second heating element. The protrusion directs the cooling air upward toward the coil of the second heating element as it progresses over the base plate in the second air flow path by orienting upward. In this way, cooling efficiency is increased.

[0018] Preferably, the base plate and the fins are made of plastic injection in an integrated structure. The integrated structure facilitates easy production and increases product life by preventing deformation of the fins over time.

[0019] BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 is a perspective assembly view of the representative construction of the induction hob with an axial fan according to the invention. Figure 2 is an exploded view of the induction hob shown in Figure 1 with the axial fan disassembled.

[0021] Figure 3 is a perspective view of the diffuser element of the induction hob connected to the fan housing in a representative construction.

[0022] Figure 4 is a top view of the diffuser element given in Figure 3 with the fan mounted on the fan housing.

[0023] DETAILED DESCRIPTION OF THE INVENTION

[0024] In this detailed description, the development subject to the invention is described with references to examples, solely to better explain the subject without any limitation.

[0025] In Figure 1 , a representative construction of the induction hob according to the invention is shown in perspective with an open-top metal tray-shaped housing (10) with its ceramic glass top plate removed. In the housing (10) of the induction hob, there is a first heating element (20) and a second heating element (40) controlled by a single circuit board (80). The housing (10) has a flat and planar base plate (12) and flat strip-shaped side edges (11 ) surrounding the perimeter of the base plate (12) perpendicularly. The top plate (not shown) is placed flatly on top of the side edges (11 ). The first and second heating elements (20, 40) have the same structure and provide heating by induction. For this purpose, the first heating element and the second heating element (20, 40) include respective flat first coil (24) and second coil (44), which are wound in interleaved hexagonal rings. The first and second coils (24, 44) are fixed at a distance from each other to the base plate (12) with circular frames (22, 42) on which they are mounted. The electronic circuit board (80) extends under the frames (22, 42). An IGBT circuit that generates high heat is located on the upper wall of the circuit board (80). A prismatic heat sink (30) made of aluminum is placed in a way that it provides heat conduction, extending between the frames (22, 42) on the upper wall (82) of the circuit board (80), close to the side edge (11 ) of the base plate (12).

[0026] In Figure 2, the components on the induction hob are shown exploded. A ventilation opening (14) is provided on the base plate (12) of the housing (10) concentric with the center of the first coil (24) adjacent to the corner. The ventilation opening (14) is in the form of a circular grille and allows the external ambient air to pass into the housing (10). A fan housing (60) sits on the base plate (12) concentrically with the ventilation opening (14) via a circular side wall (62). The fan housing (60) has a deflector plate (64) on the side wall (62) that covers half of the fan outlet surrounded by the upper edge of the side wall (62). The deflector plate (64), together with the side wall (62) in the form of a circular strip, forms a structure similar to a radial fan casing with a partially open top surface. On the side of the side wall (62) facing the second heating element (40), an extension with a partially rectangular cross-section is made to form a nozzle-shaped fan outlet (66). The fan outlet (66) is connected via a flat bridge element (68) facing the inlet (72) of an opposing diffuser element (70). The diffuser element (70) and the fan housing (60) are produced as a monoblock by plastic injection molding. An aluminum monoblock heat sink (30) extending along its length is mounted on the bridge element (68) and has a rectangular prismatic structure. The heat sink (30) is adjacent to the fan outlet (66) at one end and to the inlet (72) of the diffuser element (70) at the other end.

[0027] An impeller (56) mounted on its rotation axis is placed together with a motor (54) to the side wall (62) of the fan housing (60). The motor (54) and the impeller (56) rotatably connected to it are fixed at their center to a mounting bracket (52) in the form of a plastic bridge. The mounting bracket (52) is locked onto the upper edge of the side wall (62) from its opposite ends. When the axial fan (50) is mounted on the fan housing (60), its impeller (56) rotates and creates low pressure at the ventilation opening (14), drawing external ambient air into the housing (10). Since the rotation axis of the axial fan (50) is perpendicular to the base plate (12), the ambient air passes through the axial fan (50) and reaches the first heating element (20) directly from the open part of the side wall (62).

[0028] The diffuser element (70) has a base plate (74) similar to a truncated circle with raised peripheral edges (75). The base plate (74) extends at a distance under the coil (44) of the second heating element (40), forming an air passage corridor.

[0029] In Figure 3, the fan housing (60) and the associated diffuser element (70), which form the air guide channel inside the housing (10), are shown in perspective. The fan housing (60) is in the form of a radial fan casing with a half-circle cut from the top, providing the axial fan (50) outlet. Next to the axial air flow path (f 1 ) perpendicular to the base plate (12) above the axial fan (50), the pressurized air is radially discharged in the part covered by the deflector plate (64) through the nozzle-shaped fan outlet (66), providing an air flow in the direction of the second air flow path (f2). The second air flow path (f2) is adjacent and parallel to the side edge (11 ) of the housing (10). When the pressurized air is discharged from the fan outlet (66), it passes over the bridge element (68) and is taken into the diffuser element (70) having an inlet (72) of equal width to the fan outlet (66), passing through a protrusion (73) and gaining an upward velocity vector. As shown from above in Figure 4, the air passing through the protrusion (73) is passed between angled fins (a-e) that are adjacent and expanding, and distributed over the flat and planar base plate (74) to form a largely homogeneous and laminar third air flow path (f3). Here, some of the fins (b-e) are bent at an angle from a front wall (722) extending perpendicular to the inlet (72), forming an air corridor that expands at an angle from one end at the inlet (72) to the other end over the base plate (74). The first fin (a) divides into two the air corridor formed by the adjacent fin (b) reaching the inlet (72). In this way, similar to the opening fingers of a hand, the fins (a-e) define multiple adjacent air channels where the narrow air channel expands. A wider adjacent corridor structure is obtained in the middle, with the corridor remaining in the middle of the fins (a-e) having the widest end. The end tips of the fins (a-e) are aligned equally in the transverse direction. Additionally, the fins (a-e) have a triangular-like form with long edges extending on the base plate (74). The fins (a-e) are flat and planar and are integrated with the base plate (74).

[0030] When the axial fan (50) is operated, the motor (54) attached to the mounting bracket (52) rotates the impeller (56) in the direction perpendicular to the base plate (12), and the air drawn from the ventilation opening (14) passes through the open part of the side wall (62) of the fan housing (60) directly towards the first heating element (20), cooling the first coil (24) on the frame (22). In the part covered by the deflector plate (64) on the side wall (62), the air pressure increases in the enclosed volume formed with the adjacent side wall (62) portion, and is radially discharged from the fan outlet (66). The air flow in the blowing direction of the axial fan (50) forms the first air flow path (f1), and the radial air flow forms the second air flow path (f2) perpendicular to the first air flow path (f1). The air discharged from the fan outlet (66) follows the second air flow path (f2) and passes over the heat sink (30) from a front wall (31) adjacent to the fan outlet (66) to a rear wall (33) at the opposite end.

[0031] The heat sink (30) is a monoblock aluminum extrusion profile similar to a rectangle and has cooling walls obtained with an upper channel (32) and a lower tunnel (34) adjacent from both sides. Additionally, the upward-facing surface of the second tunnel (34) has a downward inclined extension (35). It has been determined that the described profile of the heat sink (30) effectively cools the heat sink (30) with the cooling air progressing in the second air flow direction, and does not disturb the flow profile during this time. The rear wall (31 ) of the heat sink (30) abuts the inlet (72) of the diffuser element (70). Indeed, each vertical edge of the profile of the first and second tunnels (32, 34) abuts a fin (b-e) from the front wall (722) corresponding to the inlet (72). In this way, air flow corridors extending along the second air flow path (f2) from the nozzle-shaped fan outlet (66) to the center of the base plate (74) and the subsequent third air flow path (f3) have been obtained. In this way, the transmission of the pressurized air partially conveyed radially by the axial fan (50) to the second cooling element (40) without vortex formation has been ensured. REFERENCE NUMERALS

[0032] 10 Housing 50 Fan

[0033] 11 Side edge 52 Mounting bracket

[0034] 12 Base plate 54 Motor

[0035] 14 Ventilation opening 56 Impeller

[0036] 16 Outlet hole 60 Fan housing

[0037] 20 First heating element 62 Side wall

[0038] 22 Frame 64 Deflector plate

[0039] 24 First coil 66 Fan outlet

[0040] 30 Heat sink 68 Bridge element

[0041] 31 Front wall 70 Diffuser element

[0042] 32 Upper channel 72 Inlet

[0043] 33 Rear wall 722 Front wall

[0044] 34 Lower tunnel 73 Protrusion

[0045] 35 Inclined extension 74 Base plate

[0046] 40 Second heating element 75 Peripheral edge

[0047] 42 Frame 80 Circuit board

[0048] 44 Second coil 82 Upper wall f1 First air flow path a-e Fins f2 Second air flow path f3 Third air flow path

Claims

CLAIMS1. An induction hob comprising a housing (10) with a ventilation opening (14); an induction first heating element (20) and a second heating element (40) mounted spaced apart within the housing (10); at least one fan (50) arranged to convey the cooling air it produces by accelerating the ambient air supplied from the ventilation opening (14) via a first air flow path (f1 ) directed towards the first heating element (20) and at least one second air flow path (f2) directed towards the second heating element (40); characterized in that a diffuser element (70) is having a base plate (74) over which the cooling air progressing in the second air flow path (f2) received via an inlet (72) is carried and which extends at least partially under the second heating element (40), and at least one fin (a-e) on the base plate (74) that directs the cooling air supplied from the inlet (72) to radially expand over the base plate (74).

2. An induction hob according to claim 1 , wherein multiple fins (a-e) in the diffuser element (70) are arranged adjacent to each other to form expanding channels from the narrow part facing the inlet (72).

3. An induction hob according to claim 2, wherein the fins (a-e) are in a triangular-like geometric form erected from one edge on the base plate (74).

4. An induction hob according to claims 2-3, wherein the fins (a-e) have a front wall (722) extending parallel to the second air flow path (f2).

5. An induction hob according to claims 2-5, wherein the deviation angle of the fins (a-e) relative to the second air flow path (f2) is adjusted to increase from end to end.

6. An induction hob according to claim 5, wherein the deviation angle is adjusted between 10-60 degrees.

7. An induction hob according to claims 2-6, wherein it includes a heat sink (30) with cooling walls (32) extending transversely parallel to each other through which the second air flow path (f2) passes between corresponding ends where the fins (b-e) engage.

8. An induction hob according to any of the preceding claims, wherein the second heating element includes a frame (42) containing ferrite and a second coil (44) wound on the frame (42).

9. An induction hob according to any of the preceding claims, wherein the diffuser element (70) includes a peripheral edge (75) provided on the periphery of the base plate (74) in a way that limits the inlet (72).

10. An induction hob according to any of the preceding claims, wherein the fan (50) is a single axial fan (50), and the ventilation opening (14) is provided on the base plate (12) of the housing (10) so that it remains under the air inlet of the axial fan (50), and includes a deflector plate (64) adapted to the fan housing (60) to form the second air flow path (f2) in the radial direction of the axial fan (50).

11. An induction hob according to any of the preceding claims, wherein the diffuser element (70) includes a protrusion (73) provided adjacent to the inlet portion (72), which deflects the second air flow path (f2) upward toward the second heating element (40).

12. An induction hob according to any of the preceding claims, wherein the base plate (74) and the fins (a-e) are made of plastic injection in an integrated structure.

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