EP2844029B1 - Heating device and method for operating a heating device - Google Patents

Description

The invention relates to a heating device and a method for operating a heating device.

From the EP 1448024 A1 It is known in a heating device having a plurality of independent and separate long heating elements, divide them into three heating elements. A first and a second heating element are connected via an excess temperature fuse in the form of a so-called rod controller to a power supply. The overtemperature fuse switches off the two heating elements in the event of an overtemperature. Such an excess temperature may be about 500 ° C to 600 ° C and considered a threat to a cooktop plate made of glass ceramic. A third heating element is connected directly to a power supply without monitoring by the over-temperature fuse and without interposing the over-temperature fuse. The electrical power of the third heating element is significantly lower than that of the first second heating element du.

From the US 5,171,973 It is known to interconnect two or three heating elements in such a heater together. One of the heating elements is a so-called halogen heater, which ensures a special fast glow or a visible heating operation. In this case, in the case that only two heating elements are operated, these two heating elements each operated the same, so either both with a monitoring by an overtemperature fuse or both without such.

Task and solution

The invention has for its object to provide an aforementioned heating device and a method for their operation, with which problems of the prior art can be solved and it is particularly possible, an accelerated operation on the one hand and a holding operation in conjunction with to enable a so-called energy regulator on the other hand.

This object is achieved by a heating device with the features of claim 1 and a method having the features of claim 12. Advantageous and preferred embodiments of the invention are the subject matter of further claims and are explained in more detail below. Some of the features are described only for the heater or only for the method. However, they should be able to apply independently for both the heater and for the procedure independently.

It is envisaged that the heating device is provided for a hotplate in a hob or over her such a hotplate is formed. The heater has a plurality of independent and separate long or elongated heating elements, for example according to the EP 590315 A which are arranged in loops and / or spirally and / or meandering and / or substantially along concentric circles on a support of the heating device. The carrier has at least one central region in the middle or around a center and an outer region which adjoins an outer edge. The width of the central region and the width of the outer region may be approximately equal, and preferably the central region may be somewhat wider, for example 10% to 30% or even to 40%. The heating elements extend in an intermeshing manner on the carrier and cover its essential area. This is from the aforementioned EP 590315 A known.

The heater or the carrier is overlapped by an over-temperature fuse or it is located above it. It can detect the temperature above the heating device or at least the reaching of a certain temperature, namely the so-called excess temperature at the heating device. Then the excess temperature fuse can act on the heater so that their heating power is lowered and the temperature goes back again. At least a first heating element is connected via this excess temperature fuse to a power supply for switching off the first heating element in the event of an excess temperature. A second heating element, preferably only the second heating element, is connected to a power supply without the interposition of this or another over-temperature fuse.

According to the invention, the second heating element is arranged both in the central area and in the outer area on the carrier, advantageously distributed in each case, wherein it has at least one turn in each of the two areas or rotates once. Thus, in simple terms, the second heating element is provided in an outer area of the heater and in an inner area of the heater and not only outside or inside only. Thus, both a mentioned holding operation with low power and an additional increased power in the parboiling operation can be better achieved.

In an advantageous embodiment of the invention, it is provided that in two areas in which the second heating element extends, the carrier is circular. The central area lies within an inner radius range of up to 50% or 60% of the radius. The outer area just adjoins it on the outside and thus lies in an outer radius area over 40% or 50% of the radius. Then the second heating element extends in two areas, so to speak, inside and outside.

In an alternative embodiment, an intermediate region is provided between the central region and the outer region, in which also the second heating element extends with at least one turn. Although the width of the three areas may be approximately equal, advantageously the width of the central area is greater. Again, the carrier may be circular, wherein the central region in an inner radius range up to 40% to 50% or even up to 60% of the radius. The intermediate area adjoins the central area on the outside in an intermediate radius range of 40% or 50% to 70% or 80% of the radius. Adjoining the outside, in turn, is the outer area, which lies in an outer radius area over 70% or 80% of the radius.

In a modification of the invention, the carriers may not be circular in the two aforementioned alternatives, but oblong oval or approximately rectangular. Then, the information for the widths or radii of the two or three areas applies accordingly, the percentages are then not based on the radius of a circular shape, but are based on the narrowest half width of the entire heater.

In an advantageous embodiment, the largest area of the carrier is covered with heating elements. Advantageously, it is covered by at least 10% or 20% of the radius to 100% of the radius, in particular to a maximum of 95%, with at least one heating element. A distance of the heating elements or two adjacent turns of the heating elements may be in the range of a few mm, for example 2 mm to 5 mm or even 8 mm. Advantageously, this distance is substantially equal for the entire heater.

It can be provided that an outermost turn of the heating device is not formed by the second heating element, but for example by the first heating element or a third. Furthermore, it can be provided that a second outermost turn of all heating elements or the heating device is formed by the second heating element. Thus, it is also the outermost turn of the second heating element.

It may be provided that at most a third-innermost turn of the heating elements or the heating device is formed by the second heating element as its innermost turn. Advantageously, it is only a fourth-innermost turn, so that no turn of the second heating element is provided around a center of the heater, but advantageously only the first heating element.

In an advantageous embodiment of the invention it is provided that the second heating element is arranged substantially double parallel to each other on the carrier in so-called double turns. Between two double turns of the second heating element, in particular between the two outermost double turns of the second heating element, at least one turn, preferably at least one double turn, of another heating element or of the first heating element is provided. This ensures that no two double turns of the second heating element run directly next to one another, because otherwise an excessively large annular region of the heating device or on the support would be covered only by the second heating element and this could mean an undesirably high power concentration without over-temperature protection. Advantageously, the second heating element is arranged only in double turns on the carrier. This can also apply to other heating elements. Between two double turns of the second heating element, two or four turns of another heating element, which may be the first heating element, but under certain circumstances also a third heating element, always run in an advantageous manner.

The heater may be formed as a two-circuit heater and have three heating elements, in which case advantageously also the three aforementioned areas are provided as a central region, intermediate region and outer region. A first heating element may be provided above all in the central area and not in the outer area. A third heating element can be provided, especially in the outer area and advantageously not in the central area. A second heating element runs just as described above in all three areas.

In an advantageous embodiment of the invention, the excess temperature fuse is a so-called rod controller with an elongated thermo-mechanical expansion element. Such rod controller are known for example from the DE 3333645 A or DE 3423086 A , At a certain temperature, a switch is triggered by the thermo-mechanical expansion element and thus the first heating element, under certain circumstances, the aforementioned third heating element, off.

It can be provided that the power of the second heating element at a mains voltage of 230 volts is a maximum of 1200 watts, preferably 1000 watts. Its area performance can advantageously be less than 2.5 W / cm ² .

Thus, according to the invention, the second heating element is operated without the interposition of the excess temperature fuse and also without monitoring by the excess temperature fuse. In a holding operation of the hotplate or the heating device, the second heating element operated alone without the overtemperature fuse. In a normal cooking operation, the second heating element may be switched on as needed, but does not have to. During a warm-up operation, all heating elements of the heating device are operated, in particular in the case of a two-circuit heater in two-circuit operation. Then, the second heating element for a particularly large parboiling performance has the advantage that at too high a temperature the over-temperature fuse to protect a glass ceramic cooktop panel responds and a first and possibly a third heating element for safety reasons off. However, in order for the electrical power not to return to zero directly thereafter, but at the same time a smaller power can not be generated by the deactivated heating elements without changing the power level set by an operator, the second heating element can continue to operate. Its area performance is relatively low due to the large distribution, which is advantageously just less than 2.5 W / cm ² . If then the temperature has dropped below the cooktop panel again so far that the excess temperature fuse releases the first and the third heating element again or turns back on, they can work again in addition and with very high overall performance.

These and other features will become apparent from the claims but also from the description and drawings, wherein the individual features each alone or more in the form of sub-combinations in an embodiment of the invention and in other fields be realized and advantageous and protectable Represent embodiments for which protection is claimed here. The subdivision of the application into intermediate headings and individual sections does not limit the general validity of the statements made thereunder.

Brief description of the drawings

Fig. 1

eine schematische Darstellung eines Trägers für eine erfindungsgemäße Heizeinrichtung mit Aufteilung in drei Radiusbereiche,

Fig. 2

eine Heizeinrichtung mit dem Träger aus Fig. 1 und mit drei Heizelementen belegt, wobei nur ein innerstes Heizelement aktiv ist,

Fig. 3

die Heizeinrichtung aus Fig. 2 in einem anderen Betriebszustand mit allen drei Heizelementen aktiviert,

Fig. 4

eine Abwandlung des Trägers aus Fig. 1 mit einer Aufteilung in zwei Radiusbereiche,

Fig. 5

eine Darstellung eines Schaltschemas für eine Ansteuerung mit einem Aufsetzschalter für die Heizeinrichtung aus Fig. 3 und

Fig. 6

einen schematisch dargestellten Energieregler mit Beschreibung seiner Drehwinkelbereiche.

Embodiments of the invention are shown schematically in the drawings and are explained in more detail below. In the drawings show:

Fig. 1

a schematic representation of a support for a heating device according to the invention with division into three radius ranges,

Fig. 2

a heater with the carrier off Fig. 1 and occupied by three heating elements, with only one innermost heating element being active,

Fig. 3

the heater off Fig. 2 activated in a different operating state with all three heating elements,

Fig. 4

a modification of the carrier Fig. 1 with a division into two radius ranges,

Fig. 5

an illustration of a circuit diagram for a drive with a Aufsetzschalter for the heater off Fig. 3 and

Fig. 6

a schematically illustrated energy regulator with description of its rotation angle ranges.

Detailed description of the embodiments

In the Fig. 1 is a carrier 10 for an electric heater 11 accordingly Fig. 2 shown, which is circular in shape with a peripheral support edge 10 a and one in the Fig. 2 centrally shown central support elevation 10b. The flat surface of the carrier 10 within the carrier rim 10a is divided into three radius regions, namely a central region I, an intermediate region II and an outer region III. The central region I has a radius r ₁ and a width b ₁ . The intermediate region II extends with a width b ₂ between the radii r ₁ and r ₂ . The outer region III extends with a width of b ₃ between the radii of r ₂ and r ₃ . It can be seen that the radius r _{1 has} almost 50% of the total radius of the carrier 10 or within the carrier rim 10a. The radius r ₂ is about 75% and the radius r ₃ almost 100% within the support edge 10 a. The width b _{1 of} the central area I is thus slightly larger than that of the other areas II and III, wherein the area required for the support elevation 10b is taken into account.

In the Fig. 2 is shown how a rod controller 13 is arranged with a switch housing 14 and a long sensor 15 on the carrier 10 and the heater 11. The elongated straight sensor 15 extends to the support elevation 10b and is placed there in a known manner and optionally attached with a clamp. In addition to the rod controller 13 or its switch housing 14, a connection region 17 is provided with a plurality of terminal lugs or plug connections as electrical contacting to the heating elements.

The heating elements of the heating device 11 run on the carrier 10. When shown in solid black, a first heating element 20, which runs in the inner two regions I and II, In particular, the three innermost turns in the central region I forms. It is connected to a terminal lug 17 ', which is connected to the rod controller 13 and the rod controller 13 is looped into its power supply. It is also on.

A second heating element 22 extends in three double turns. The innermost double turn runs in the central region I, and indeed quasi embedded in the middle of the first heating element 20. The middle double turn extends radially outward on the first heating element 20 adjacent in the intermediate region II. The third and outermost double turn of the second heating element 22 extends relatively far outside on the support 10 in the outer region III. Radially outside thereof, only a single turn of a third heating element 24 is provided, which extends in the outer region III and in the transition to the intermediate region II. The third heating element 24 here has only a double turn and the outermost single turn on. As described above for the first heating element 20, the third heating element 24 is connected via the terminal lug 17 'with looped rod controller 13 as an over-temperature fuse to a power supply.

It can be seen at the connection region 17 that the three heating elements 20, 22 and 24 can each be switched on or controlled separately. The electrical connections to the second heating element 22 pass the rod regulator 13 or the corresponding connection lug 17 '.

Along the course of the sensor 15, the passage between the three areas I, II and III is again represented by the circled vertical lines.

In operation here is in Fig. 2 only the first heating element 20. Since the entire heater 11 is designed as a so-called two-circuit heater, the first heating element 20 forms in single-circuit operation, the first circle or the small diameter, the diameter can be considered here as a hotplate with about 140 mm , When operating as a single circuit according to Fig. 2 the heating power of the first heating element 20 at 230 volts is about 1200 watts. The second heating element 22 and the third heating element 24 are turned off in this case.

In the Fig. 3 is in itself the representation of Fig. 2 repeated. Here, the second heating element 22 is shown filled corrugated and the third heating element 24 is not marked for distinction. In Fig. 3 all three heating elements 20, 22 and 24 are in operation. In this two-circuit operation, the diameter is about 230 mm. The total electrical power is then at a supply voltage of 230 volts 3200 watts, all three heating elements are therefore parallel connected. The second heating element 22 and the third heating element 24 have a heating power of about 1000 watts each.

With the known function of the rod controller 13 it can be seen that at an excess temperature, the first heating element 20 and the third heating element 24 are switched off by the rod controller 13. However, the second heating element 22 may be operated at a higher power without such over-temperature protection due to the wide-spread or exploded distribution. This can be increased overall in a desired operation with very high power or high parboiling power as a boost operation power generation. Furthermore, theoretically, due to the relatively low power of the second heating element, which is less than the above-mentioned 2.5 W / cm ^{2 in} terms of its total heated surface, a low continuous power could be achieved per se. Operation with a large pot may be available. For this purpose, the second heating element would have to be advantageously controlled electronically.

Furthermore, as an alternative, the unprotected power of the second heating element 22 can also be switched out, in particular if the heating operation is not present, and a power of a maximum of 2200 watts remains. At a minimum power release via a power controller or energy regulator, for example, according to the DE 102008014805 A1 or DE 2625716 A , of 6% this results in 132 watts as a total output. Although this is relatively little, but may be sufficient for a holding operation at the hotplate in two-circuit operation with full area.

In the Fig. 5 is a circuit diagram for the heater 11 according to the invention together with the usual energy regulator as a power control device 25, as is known and especially with a power control device according to the DE 2625716 A together with additional switches or Aufsetzschalter 26 can be realized. It controls via the so-called duty cycle ED according to the DE 19736308 A1 the on and off times of the heating elements or the clock ratio the energy supply. Shown dashed lines is a Aufsetzschalter 26 which is additionally placed on such a dash-dotted line power control device 25 and is rotated by the same rotary shaft. In addition to power adjustment via the power controller 25, the override switch 26 may switch on or off the second heater 22 shown below.

The Fig. 6 shows the adjustment options for the heating device 11 according to the invention according to the inventive method. From the zero position at 0 ° or at OFF can to the left be rotated counterclockwise, resulting in the so-called single-circuit operation. In this case, only the first heating element 20 is operated and therefore this single-circuit operation is for the invention largely without interest.

Turning from the zero position at 0 ° at OFF to the right in a clockwise direction, this leads to the two-circuit operation with the heating elements 20 and 24. At 45 ° a detent is provided with a detent position, which corresponds to a maximum power. Here, a value for ED of 100% for the heating elements 20 and 24 is provided and the second heating element 22 is also switched on the Aufsetzschalter 26. Consequently, the heating elements 20 and 24 are actually turned on as default permanently, only the excess temperature fuse switches them over the rod controller 13 from reaching its switching point. Then, however, the second heating element 22 continues to operate as previously explained.

If it is rotated further to the right, the value for ED becomes lower until it reaches the lowest value at an angle of about 167 °, namely ED = 6%, whereby this position can be determined by a detent and / or a stop. Furthermore, the second heating element 22 is switched off at an angle greater than 45 ° via the Aufsetzschalter 26, so that it is just ever operated only at the maximum power. At the position of 167 °, at 6% power of the heating elements 20 and 24, which together have 2200 watts, a low power of 132 watts is present, which is advantageous for an aforementioned holding operation.

In the Fig. 4 is as a modification of the presentation Fig. 1 a heating device 111 according to the invention is shown with a carrier 110, wherein the surface of the carrier 110 is divided only into a central region I 'and an outer region II'. The central region I 'extends to a radius of r ₁ and has a width of b ₁ . The outer region II 'extends from the radius r ₁ to a radius r ₂ and has a width of b ₂ . Here, the above said applies accordingly, the second heating element 22 of Fig. 2 and 3 could be in the central area I 'and the outside area II'. A first heating element and possibly also a third heating element could be divided into the central area I 'and the outer area II'.

Claims (15)

1. Heating device (11) for a cooking point in a hob, wherein the heating device has a plurality of independent and separate long heating elements (20, 22, 24) which are arranged on a support (10) of the heating device in loops and/or in a spiral manner and/or substantially along concentric circles, wherein the support has at least a central region (I) around the centre point and an outer region (III) adjoining an outer edge (10a), wherein the width of the central region (I) and of the outer region (III) is approximately equal, wherein the heating elements (20, 22, 24) run on the support (10) so as to engage one in the other and cover a significant area of said support, wherein an overtemperature protection means (13) engages over the heating device or the support for the purpose of detecting the temperature at the heating device, wherein at least a first heating element (20) is connected to an energy supply means (25, 26) by means of the overtemperature protection means (13) in order to switch off the first heating element (20) in the event of an overtemperature, wherein a second heating element (22) is connected to an energy supply means (25, 26) without interconnection of said overtemperature protection means or another overtemperature protection means,
   characterized in that
   the second heating element (22) is arranged on the support (10) in the central region (I) and in the outer region (III).
2. Heating device according to claim 1, characterized in that the support (100) is circular, and the central region (I') lies in an inner radius range (r₁) of up to 60% of the radius and the outer region (II') lies in an outer radius range (r₃) of over 60% of the radius.
3. Heating device according to claim 1, characterized in that an intermediate region (II) is provided between the central region (I) and the outer region (III), wherein the width of the central region (I), of the intermediate region (II) and of the outer region (III) is approximately equal, and wherein the second heating element (22) also runs in the intermediate region (II).
4. Heating device according to claim 3, characterized in that the support (10) is circular and the central region (I) lies in an inner radius range (r₁) of up to 40% of the radius, the intermediate region (II) lies in an intermediate radius range (r₂) of 40% to 70% of the radius and the outer region (III) lies in an outer radius range (r₃) of over 70% of the radius.
5. Heating device according to any of the preceding claims, characterized in that at least 10% of the radius up to a maximum of 100 %, in particular up to a maximum of 95%, of the radius of the support (10) is covered by at least one heating element (20, 22, 24).
6. Heating device according to any of the preceding claims, characterized in that a second-outermost turn of the heating elements is formed by the second heating element (22) as the outermost turn of said second heating element.
7. Heating device according to any of the preceding claims, characterized in that, at most, a third-innermost turn of the heating elements is formed by the second heating element (22), in particular a fourth-innermost turn.
8. Heating device according to any of the preceding claims, characterized in that the second heating element (22) is arranged on the support (10) substantially in duplicate parallel next to another in double turns, wherein at least one turn, preferably at least one double turn, of another heating element or of the first heating element (20) is provided between two double turns of the second heating element (22), in particular the two outermost double turns.
9. Heating device according to claim 8, characterized in that the second heating element (22) is arranged on the support (10) only in double turns, wherein preferably two or four turns of another heating element or of the first heating element (20) run between two double turns.
10. Heating device according to any of the preceding claims, characterized in that the overtemperature protection means is a rod-type thermostat (13) with a thermomechanical expansion element (15) and a switch which is tripped at a specific temperature by the thermomechanical expansion element.
11. Heating device according to any of the preceding claims, characterized in that the power of the second heating element (22) is at most 1200 watts during operation at a mains voltage of 230 volts.
12. Method for operating a heating device according to any of the preceding claims, characterized in that the second heating element (22) is operated without the interconnection of an overtemperature protection means (13) and without monitoring by the overtemperature protection means (13).
13. Method according to claim 12, characterized in that, in a keep-warm mode of the cooking point or of the heating device (11), the second heating element (22) is operated on its own, without overtemperature protection (13).
14. Method according to claim 12 or 13, characterized in that, in a normal cooking mode, the second heating element (22) and at least one further heating element or the first heating element (20) are operated together, and in particular connected in parallel with one another.
15. Method according to claim 12 or 13, characterized in that, in an initial cooking mode with a maximum power of the heating device (11), the second heating element (22) and at least one further heating element or the first heating element (20) are operated together, and in particular connected in parallel with one another, in order to increase the power generated.

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