An induction hob with an axial fan deflector 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 second heating element (40) mounted spaced apart within the housing (10); and an axial fan (50) located under the first heating element (20), which accelerates the ambient air supplied from the ventilation opening (14) and cools via a first air flow path (f1) proceeding from the air outlet towards the first heating element (20). The induction hob further comprises a deflector plate (64) that pressurizes the air flow at the air outlet of the axial fan (50) by forming a second air flow path (f2) at an angle with the first air flow (f1 ), radially directing the air flow rate towards the second heating element (40), and the power of the axial fan (50) is adjusted to cool the second heating element (40) solely with the air flow rate of the second air flow (f2).

Description

[0001] AN INDUCTION HOB WITH AN AXIAL FAN DEFLECTOR PLATE

[0002] TECHNICAL FIELD

[0003] The present invention relates to an induction hob where the cooling system comprises an axial fan, particularly where the air conveyed by the axial fan is directed into a guidance channel.

[0004] STATE OF THE ART

[0005] In induction hobs, the IGBT elements used are exposed to high currents and voltages during power switching operations. This situation leads to energy losses due to their electrical resistance and causes them to heat up. Heating can affect the performance of IGBT elements and can even cause serious malfunctions in case of overheating. Therefore, effective cooling of the IGBT elements is necessary. Ferrite materials are used in the coils that constitute the basic principle of induction hobs. Ferrite materials have a high ability to direct magnetic fields and can exhibit these properties up to a certain temperature (up to the saturation temperature). As a result, reaching the saturation temperature of these materials adversely affects the operation of the system. Therefore, cooling of the coils in hobs is necessary. Increasing the air flow rate supplied to the coil will prevent the ferrite material from reaching its saturation temperature. In this way, the ferrite material does not exceed its working temperature before reaching the saturation temperature, and unwanted changes in its magnetic properties do not occur. This situation increases the lifespan and performance of induction hobs.

[0006] In induction hobs, cooling fans are used to provide direct air flow to the coils and IGBT elements. Generally, axial fans are preferred. Axial fans create air flow in parallel, generating air movement in a large volume, and they generally move air by pushing it in a single direction. This is a factor that limits ability to direct the air flow as needed.

[0007] WO2011154373A1 relates to an induction heating cooker comprising more than one induction coil, providing the cooking container of ferromagnetic feature placed thereon to be heated by the magnetic field it generates, an upper plate disposed above the induction coils, produced from a material like glass or ceramic, more than one circuit board providing the induction coils to be energized, more than one switching element like IGBT or diode bridge connected to the circuit boards carrying high value electric current and overheated due to the effect of the current, and a lower plate disposed at the underside of the upper plate, where on the circuit boards are arranged horizontally side by side at intervals, an axial type fan disposed in an opening arranged on the lower plate, and a heat sink disposed over the opening to be concentric with the fan and surrounding the fan.

[0008] BRIEF DESCRIPTION OF THE INVENTION

[0009] The object of the invention is to increase the cooling performance by pressurizing the air in the axial cooling fan found in induction hobs and directing it to the rear coils.

[0010] In order to achieve the above objective, the invention comprises 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; and an axial fan located under the first heating element, which accelerates the ambient air supplied from the ventilation opening and cools via a first air flow path proceeding from the air outlet towards the first heating element. The induction hob further comprises a deflector plate that pressurizes the air flow at the air outlet of the axial fan by forming a second air flow path at an angle with the first air flow, radially directing the air flow rate towards the second heating element, and the power of the axial fan is adjusted to cool the second heating element solely with the air flow rate of the second air flow. In this way, it is possible to cool multiple heating elements with a single axial fan. By eliminating the need for a separate axial fan for the second heating element, it becomes possible to achieve a more compact structure for the induction hob housing. In addition, by positioning the noise-producing axial fan, for example, at the rear part of the housing away from the user, the noise reaching the user during use is reduced.

[0011] Preferably, the ventilation opening is provided in the base plate of the housing so that it remains under the axial fan air intake. In this way, during the operation of the hob, it becomes possible for the axial fan to draw ambient air directly from the air inlet by being placed parallel to the base. In this case, the air inlet path is shortened, and the efficiency of the axial fan increases.

[0012] Preferably, the ventilation opening is coaxially aligned with a first coil of the first heating element and the axial fan. In this way, the first air path of the axial fan is shortened, and the cooling air is delivered to the coil of the first heating element by minimizing the pressure loss. Preferably, the deflector plate is arranged to partially cover the axial fan outlet from above. Simply by placing an upper shield on the axial fan housing, a compact construction is provided. In addition, cooling air can be taken radially in the second air flow path at a strong flow rate from the axial fan.

[0013] Preferably, a side wall joins at the front edge of the deflector plate and peripherally surrounds the propeller of the axial fan. In this way, the radial air outlet and partially axial air outlet of the axial fan are limited by the housing formed by the side wall and the deflector plate. The axial and radial direction of the air flow is simply achieved with the housing of the axial fan.

[0014] Preferably, a fan outlet is provided on the side wall, adjusted to face the second heating element and covered from above by the deflector plate. The fan outlet, by partially blocking and pressurizing the axial air in the axial direction with the deflector, allows it to be limited and directed towards the second heating element. In this case, it is ensured that the air is accelerated to reach the second heating element.

[0015] Preferably, the fan outlet is in the form of a nozzle extending radially outward from the side wall. With the nozzle, it is possible to deliver the air in the second air flow path radially without dispersion.

[0016] Preferably, a mounting bracket carries the propeller of the axial fan and is attached from its opposite ends to the upper edge of the side wall. Thus, the side wall both limits the axial fan in the radial direction and carries the axial fan propeller to provide a compact structure.

[0017] Preferably, it includes a circuit board extending between the first heating element and the second heating element and includes a heat sink block located on the circuit board over which the second air flow path passes entirely. In this way, both the second heating element and the circuit board between it and the first heating element are cooled with the second air flow path directed radially by the axial fan. The need for a separate radial fan to cool the electronic circuit board is eliminated.

[0018] Preferably, the heat sink block includes at least one tunnel in a channel structure extending in the direction of the second air flow path provided on it. In this way, the heat transfer efficiency of the heat sink block is increased, and the cooling air proceeding in the second air flow path is enabled to perform more forced heat transfer with the heat sink block. Preferably, the heat sink block is made of a single-piece aluminum. In this way, both high heat transfer efficiency is obtained, and suitable channels are easily formed for the passage over the second air flow path.

[0019] Preferably, it includes a diffuser element located in the second air flow path, distributing the second air flow path under the second heating element. The diffuser element helps to distribute homogeneously under the second heating element the part of the cooling air supplied from the air opening and blown from the axial fan that is radially deflected through the second air flow path. In this way, the cooling efficiency of the second heating element is increased.

[0020] Preferably, the diffuser element includes a hump provided adjacent to an inlet portion close to the second heating element, deflecting the second air flow path upwards. The hump increases the cooling efficiency for the second heating element by deflecting the radial second air flow path upward towards the base of the heating element.

[0021] Preferably, the diffuser element includes fins arranged at an angle to each other, expanding from an inlet portion towards the center of the second heating element. The fins ensure that the cooling air coming in the radial direction completely reaches the base of the second heating element.

[0022] Preferably, the diffuser element is a base plate provided spaced apart under the second heater to limit a third air flow path. The base plate prevents the cooling air coming in the second air flow path from dispersing into the housing, causing it to accumulate at the base of the second heating element and rise, for example, from the middle of the coil.

[0023] BRIEF DESCRIPTION OF THE FIGURES

[0024] Figure 1 is a perspective assembly view of a representative embodiment of the induction hob with an axial fan.

[0025] Figure 2 is an exploded view of the induction hob shown in Figure 1 with the axial fan disassembled.

[0026] Figure 3 is a perspective view of the cooling assembly of the induction hob with the axial fan removed. Figure 4 is a top view of the induction hob given in Figure 3 with the axial fan assembled.

[0027] Figure 5 is a perspective view of a representative embodiment of an aluminum passive heat sink used in the induction hob according to the invention.

[0028] DETAILED DESCRIPTION OF THE INVENTION

[0029] In this detailed description, the development subject to the invention is explained with references to examples in a way that will not constitute any limitation and only to better explain the subject.

[0030] In Figure 1 , a representative embodiment of the induction hob according to the invention is shown in perspective with the housing (10) in the form of a metal tray open at the top and the ceramic glass top plate removed. The induction hob’s housing (10) includes 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 a side edge (11) in the form of a flat strip surrounding the periphery of the base plate (12) perpendicularly. The top plate (not shown) is placed flat over 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 a corresponding flat first coil (24) and a second coil (44) wound concentrically in a hexagonal ring shape. The first and second coils (24, 44) are fixed to the base plate (12) at intervals from each other with circular frames (22, 42) on which they are seated. The electronic circuit board (80) extends under the frames (22, 42). A high heat-producing IGBT circuit is located on the upper wall (82) of the circuit board (80). A prismatic heat sink block (30) made of aluminum is placed close to the side edge (11 ) of the base plate (12) extending between the frames (22, 42) on the upper wall (82) of the circuit board (80) to provide heat conduction.

[0031] 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), centered 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 passage of ambient air into the housing (10). A fan bed (60) sits on the base plate (12) concentrically with the ventilation opening (14) via a circular side wall (62). The fan bed (60) has a deflector plate (64) that covers a fan outlet up to half, surrounding it from the upper edge of the side wall (62). The deflector plate (64) together with the circular strip-shaped side wall (62) forms a structure similar to a radial fan housing partially open at the top. A fan outlet (66) in the form of a nozzle is formed by partially making a rectangular section extension on the edge of the side wall (62) facing the second heating element (40). The fan outlet (66) is connected via a flat bridge element (68) facing the entrance (72) of an opposing diffuser element (70). The diffuser element (70) and the fan bed (60) are produced integrally by plastic injection. An aluminum monolithic heat sink block (30) extending lengthwise over the bridge element (68) is in the form of a rectangular prism. The heat sink block (30) is adjacent from one end to the fan outlet (66) and from the other end to the entrance (72) of the diffuser element (70).

[0032] A propeller (56) is placed together with a motor (54) on which it is mounted from the rotation axis onto the side wall (62) of the fan bed (60). The motor (54) and the propeller (56) connected to it rotatably are fixed to a mounting bracket (52) in the form of a plastic bridge from its center. The mounting bracket (52) sits locked from its opposite ends onto the upper edge of the side wall (62). When the axial fan (50) is mounted on the fan bed (60), its propeller (56) rotates, creating low pressure at the ventilation opening (14), drawing 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 reaches directly to the first heating element (20) by passing through the axial fan (50) from the open part of the side wall (62).

[0033] The diffuser element (70) has a base plate (74) in the form of a truncated circle with elevated peripheral edges (75). The base plate (74) extends spaced under the coil (44) of the second heating element (40) to form an air passage corridor.

[0034] In Figure 3, the fan bed (60) and the connected diffuser element (70) forming the air guidance channel inside the housing (10) are shown in perspective. The fan bed (60) is in a form similar to a radial fan housing with a half-circle cut from the top, providing the axial fan (50) outlet. In the part where the deflector plate (64) covers from above the axial fan (50), the air pressure increases in the closed volume formed with the adjacent side wall (62) part, and the air is taken radially out from the fan outlet (66). The air flow in the blowing direction of the axial fan (50) constitutes the first air flow path (f1), and the air flow in the radial direction constitutes the second air flow path (f2) perpendicular to the first air flow path (f1 ). 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) with an entrance (72) of equal width to the fan outlet (66), gaining an upward velocity vector by passing through a hump (73). As shown in Figure 4, the air passing through the hump (73) is distributed over the flat and planar base plate (74) to form a largely homogeneous and laminar third air flow path (f3) by passing between the angled fins (a-e) arranged adjacent and expanding to each other. When the axial fan (50) is operated, the motor (54) attached to the mounting bracket (52) rotates in a direction perpendicular to the base plate (12), turning the propeller (56), and the air drawn from the ventilation opening (14) passes directly towards the first heating element (20) from the open part of the side wall (62) of the fan bed (60), 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 closed volume formed with the adjacent side wall (62) part and is taken radially out from the fan outlet (66). The air flow in the blowing direction of the axial fan (50) constitutes the first air flow path (f1 ), and the air flow in the radial direction constitutes 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 entirely over the heat sink block (30) from a front wall (31) adjacent to the side edge (11) of the housing (10) to a rear wall (33) at the opposite end.

[0035] In Figure 5, the heat sink block (30) is shown representatively in perspective. The heat sink block (30) is a monoblock aluminum extrusion profile similar to a rectangle and includes a first tunnel (32) and a second tunnel (34) extending parallel to each other lengthwise. The first tunnel (32) is obtained by bending upward from the top a straight outer edge (37) adjacent and parallel to the side edge (11 ) of the housing (10), forming a w-like transverse cross-sectional form. Continuing from this, a second tunnel (34) in the form of an inverted w- like transverse cross-sectional form is located. An inner edge (36) opposite to the outer edge (37) has an inward-facing channel extending lengthwise. In addition, the upward-facing surface of the second tunnel (34) is in the form of a downward sloping extension (35). It has been determined that the profile of the heat sink block (30) described ensures that the cooling air proceeding in the second air flow direction cools the heat sink block (30) effectively and does not disturb the flow profile during this process. The rear wall (31) of the heat sink block (30) rests against the entrance (72) of the diffuser element (70). Even each vertical edge of the first and second tunnels (32, 34) abuts a corresponding fin (b-e) placed at the entrance (72). As shown in Figure 4, the gaps in the expanding part of the fins (a-e) distribute the third air flow path (f3) along the entrance of the base plate (74) by expanding it.

[0036] REFERENCE NUMBERS

[0037] 10 Housing 40 Second heating element

[0038] 11 Side edge 42 Frame

[0039] 12 Base plate 50 Axial fan

[0040] 14 Ventilation opening 52 Mounting bracket

[0041] 16 Outlet hole 54 Motor

[0042] 20 First heating element 56 Propeller

[0043] 22 Frame 64 Deflector plate 24 First coil 66 Fan outlet

[0044] 30 Heat sink block 68 Bridge element

[0045] 31 Front wall 70 Diffuser element

[0046] 32 First tunnel 72 Entrance

[0047] 33 Rear wall 74 Base plate

[0048] 34 Second tunnel 75 Peripheral edge

[0049] 35 Inclined extension a-e Fin

[0050] 36 Inner edge 80 Circuit board

[0051] 37 Outer edge 82 Upper wall f1 First air flow path 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 second heating element (40) mounted spaced apart within the housing (10); an axial fan (50) located under the first heating element (20), which accelerates the ambient air supplied from the ventilation opening (14) and cools via a first air flow path (f1 ) proceeding from the air outlet towards the first heating element (20) characterized in that a deflector plate (64) that pressurizes the air flow at the air outlet of the axial fan (50) by forming a second air flow path (f2) at an angle with the first air flow (f1), radially directing the air flow rate towards the second heating element (40), and the power of the axial fan (50) is adjusted to cool the second heating element (40) solely with the air flow rate of the second air flow (f2).

2. An induction hob according to Claim 1 , wherein the ventilation opening (14) is provided in the base plate (12) of the housing (10) so that it remains under the air intake of the axial fan (50).

3. An induction hob according to Claim 2, wherein the ventilation opening (14) is coaxially aligned with a first coil (24) of the first heating element (20) and the axial fan (50).

4. An induction hob according to any of the preceding claims, wherein the deflector plate (64) is arranged to partially cover the axial fan (50) outlet from above.

5. An induction hob according to Claim 4, wherein a side wall (62) joins at the front edge of the deflector plate (64) and peripherally surrounds the propeller (56) of the axial fan (50).

6. An induction hob according to Claim 5, wherein a fan outlet (66) is provided on the side wall (62), adjusted to face the second heating element (40) and covered from above by the deflector plate (64).

7. An induction hob according to Claim 6, wherein the fan outlet (66) is in the form of a nozzle extending radially outward from the side wall (62).

8. An induction hob according to Claims 5-7, wherein a mounting bracket (52) is carrying the propeller (56) of the axial fan (50) and attached from its opposite ends to the upper edge of the side wall (62).

9. An induction hob according to any of the preceding claims, wherein a circuit board (80) is extending between the first heating element (20) and the second heating element (40), and has a heat sink block (30) located on the circuit board (80) over which the second air flow path (f2) passes entirely.

10. An induction hob according to Claim 9, wherein the heat sink block (30) has at least one tunnel (32, 34) in a channel structure extending in the direction of the second air flow path (f2) provided on it.

11. An induction hob according to Claims 9-10, wherein the heat sink block (30) is made of a single-piece aluminum.

12. An induction hob according to any of the preceding claims, wherein a diffuser element (70) is located in the second air flow path (f2), distributing the second air flow path (f2) under the second heating element (40).

13. An induction hob according to Claim 12, wherein the diffuser element (70) has a hump (73) provided adjacent to an inlet portion (72) close to the second heating element (40), deflecting the second air flow path (f2) upwards.

14. An induction hob according to Claims 12-13, wherein the diffuser element (70) has fins (a-e) arranged at an angle to each other, expanding from an inlet portion (72) towards the center of the second heating element (40).

15. An induction hob according to Claims 12-14, wherein the diffuser element (70) is a base plate (74) provided spaced apart under the second heater (40) to limit a third air flow path (f3).

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