SI8511483A - Radiant heater for cooking devices - Google Patents

Abstract

Radiant heater (11) for heating the cooker Glass ceramic tile contains electric heaters resistances of two types: dark emitters (25) in shape conventional helix-wound heating resistors low temperature wires and bright emitters (20) with high radiant temperature in the bright area, which may be formed e.g. with halogen lamps. Dark emitters (25) can be turned on before light radiators (20) to reduce the high on the one hand turn on current and in turn build regulation simpler and less complicated for the user. Alternatively to halogen light emitters can be they also use molybdenum disilicide (MoSi2). Control circuits with clock speed are proposed active power control and multi-stroke devices switches

Description

Radiant heater for cooking appliances

The invention relates to a radiant heater for cooking appliances with a glass ceramic plate, with electric light-emitting heating elements operating at elevated temperatures above 1500 K (about 1200 ° C), and whose radiation spectrum extends significantly into the field of view.

Such radiant heaters have become known e.g. from British Patent 1 273 023. These, as light-emitting heating elements, are halogen lamps, which radiate their energy in the visible and infrared region and thus radiate through the glass ceramic panel. Due to the low thermal mass, the heating times are quite short and the operator also has good control over the function due to the light radiation. However, the ability to regulate in the lower power range is difficult, requiring partly the inclusion of power diodes. Furthermore, the switching currents are often very high because the resistivity materials of light emitters have a relatively high positive temperature coefficient. The ability to regulate presupposes a greater number of light emitters that co-decide the cost of a radiant heater.

It is an object of the invention to create radiant heaters that take advantage of the good regulation ability and cost-effectiveness of the benefits of light emitters.

According to the invention, a radiator heater comprises at least one radiator zone with at least one bright radiator with a dark radiant heating element operating at temperatures below 1500 K (about 1200 ° C), which can be switched on simultaneously and / or alternately with the bright radiator.

While light emitters are preferably halogen glow emitters that can be formed as a stretched or bent tube, a molybdenum disilicide (M0SI2) -based material can also be used that can achieve, without encapsulation in the silica glass, a halogen filament lamp field of vision. The resistive material mentioned above, which is commercially available under the KanthalSuper label and has a glassy structure, has a very high switching current because its resistance at low temperatures is very low. In this case, it is advantageous to have at least one dark emitter connected in series to the boiling and baking start time, especially in the upper boiling range and in the baking range, whereas, preferably, only the dark radiators, impulse-heated under the given conditions, are included in the lower boom range. zv taktu

- 3 active power control unit. As long as the resistance of the light emitter is still low, the dark emitter acts as a barrier, whose share in the overall resistance decreases with increasing resistance of the light emitter as it is heated. This will automatically shift the power from the dark emitter to the bright emitter while reducing the starting current to an acceptable value. Preferably, two dark emitters may be provided, which are connected in front of a bright emitter in parallel, but which, in the area of the power of continuing cooking, when connected to the heating itself, bind in series.

The dark emitter is preferably conventional heater wires, most commonly mounted in a helix shape and consisting of iron-chromium-aluminum material. Materials that are on sale under the name Kanthal-A may be used. Its annealing temperatures should preferably be kept below 1500 K (approximately 1200 ° C) and lie normally at a maximum value of 1350 K (approximately 1100 ° C). They also radiate relatively brightly, but their power output is still within a fairly long range, while here, as light emitters, the designated heating elements can reach the most commonly permissible maximum temperatures, which lie well above the aforementioned temperature limits and reach or exceed in part 2000 K (approx. 1700 ° C). It may also be the case that, in the down-regulated state, the given temperature limits are also partially stepped.

Particularly preferred is the arrangement in which the dark radiators are arranged in the center region of the radiator heater, which is surrounded by the annular region in which the radiators are bright.

- 4 This visibly limits the cooking zone on the glass ceramic hob. Ideal would be a circular light emitter that encircles the heating price with dark emitters. This is possible with molybdenum disilicide heating elements that can be distributed e.g. in the form of a meander in such an annular region, however, it is technically difficult to manufacture halogen radiators in this form with a sufficient lifetime. Because of this, straight light emitters can be polygonal, e.g. in triangular or quadrangular shape arranged around the dark emitter area.

In contrast, if an even distribution of light emitters across the entire cooking surface is desired, preferably, light emitters extending perpendicularly through the heating region of the circular radiator heater may be equipped with dark emitters, with the light emitters preferably located in the area of the gap or the deepening of the plane carrying the dark radiators. This allows the height of the radiator heater to be kept low, since halogen radiators generally have a larger diameter than conventional dark radiator helixes, so that they can be better maintained in one plane by gaps.

The dark emitters can then be attached to the insulating beams of ribbon or plate form with partial insertion, the insulating beams being placed between the light emitters parallel to them. Filing can be carried out in the usual manner, preferably as described in German patent application 27 29 929, with the heating screws being fastened in the insulating material only. over a portion of its length and / or extent before its final hardening.

Although they have tightly closed bright radiators, e.g. halogen emitters, most often their own reflective layer on their quartz glass jacket, have a significantly improved degree of effect if the insulating body is provided with a reflective layer on its surface, e.g. with a layer of titanium dioxide.

Although the use of light emitters no longer warms as much as the glass ceramic plate, especially if it consists of material that is well permeable to a specific area of radiation, the temperature limit should be envisaged due to the risk of thermal damage to the glass ceramics. A rod temperature sensor can be used for this. It can be installed mainly in the area of the dark emitter, because the maximum mounting height is available there. Preferably, if it is positioned parallel to the light emitter, it captures, on the one hand, the temperature of the dark emitter, but is also affected laterally by the light emitter and does not increase the installation height significantly. The temperature limiter can be bound to disconnect the dark radiators and leave the bright radiators as residual power. This ensures that the risk of the glass ceramic plate overheating is low and that the switch contacts of the temperature limiter do not have to switch on the bright emitter with its relatively high switching current.

It is also possible to use light emitters in special binding to start cooking, as is known for other hobs from German published but not yet approved patent application 31 44 631, which we refer to here. There is a temperature switch equipped with the appropriate temperature for the start of cooking the set temperature and with such a large switch delay that after a single switch-off

- 6 does not switch on normally when the heater is operating. After a certain start-up phase, the radiant heater switches off, thus providing an automatic circuit for starting cooking.

By combining light and dark radiators, the control and control of the radiant heater is significantly improved. When used in a clocked power control device that supplies radiant energy to the heater in single power pulses with different relative switching durations, the power control device can be equipped with an additional switch which is manually operated via the adjusting shaft of the power control device, which is preferably contained in a pre-mounted switch and which switches on at least one bright emitter in the upper power range, especially when adjusting the power of the power steering device with one hundred percent relative switching duration. The light emitter here is therefore only included in the upper power range and is used for rapid heating, for which it is particularly well used. Its full turn-on duration remains short, so this relatively expensive widget with a limited lifespan is saved. In addition, switching on and off the bright radiator is a priority, due to the increased switching current, reducing the life span of frequent switching off, and thus the uncertainty of the operator due to changing illumination and dimming of the heating zone and reduced network load and reduced interference. Most of these advantages can also be achieved if, in the middle and lower power ranges, the sequential coupling of light and dark emitters by means of a power control device is provided in voltage.

Preferably, it is also possible to control the power of a radiant heater with multiple light emitters and at least one dark emitter through a multi-stroke circuit, preferably a seven-stroke circuit, in the parallel, single and sequential connection of the radiators. Most of the intermediate stages also include bright emitters, so that there is still visible control for the user, but with a smaller number of bright emitters a better degree of power is possible, especially in the lower power range.

In order to provide good optical insulation or good optical thermal insulation. a light image of the radiant heater in the cooking appliance may be provided in the edge region of the radiation shielding.

This may be formed by an annular insulating cover diaphragm, which is pressed against the cooking surface on the edge and which, because it consists of relatively denser but temperature resistant insulation material, is cut with relatively sharp edges. If it extends slightly beyond the actual inwardly insulated but less solid material, then it determines the optical effect of the cooking field itself and prevents the hob from looking torn due to its sharp internal restriction.

The radiation shielding may consist of, in addition to, or instead of a light-absorbing aperture or an overlay. reflective layers at the terminal ends of the light emitter. This prevents light from penetrating the ends of the light emitter into the area of the cooking appliance, which lies outside the hobs and illuminates the bottom of the glass ceramics in this area as well, most often unevenly, which can interfere with the optimum, which could also lead to unwanted heating. cooking appliances.

- 8 Radiation shielding may also be provided as an overlay for the terminal end of the light-reflecting heating element, which may be part of the insulation and, in particular, part of the cover aperture. Particularly preferred is a combination of these measures.

Radiation screening and related measures can also be used as a priority for a light emitter heater without the use of dark emitters.

These and further features of the preferred further embodiments of the invention are also apparent from the description and the drawing, whereby the individual characteristics can be realized in the embodiment of the invention each time for themselves or more together in the form of sub-combinations. Embodiments of the invention are shown in the drawing and will be explained in further detail. The drawing shows:

FIG. 1 is a vertical partial cross-section through a glass ceramic plate with a radiant heater underneath, FIG. 2 is a schematic diagram of a radiant heater, FIG. 3 is a schematic diagram of a variant of FIG. 4 to 8 further variants, each with an index a denoting a vertical cross-section through the radiator heater and with an index b the plan, FIG. 9 is a sectional view through a detail of a variant; FIG. 10 is a schematic diagram of a radiation heater in FIG. 11 shows an associated switch circuit with a clockwise power control device, FIG. 12 to 15 electrical switches of radiant heaters with associated power control devices,

- 9 fig. 16 and 17 each of the four radiators provided in the one radiator provided by a conventional seven-stroke switch not shown in six different power stages (a to f); FIG. 18 and 19 are a side sectional view and a plan view of a radiant heater with a temperature controller, FIG. 20 The circuit of a temperature-controlled radiant heater, FIG. 21 and 24 are vertical partial cross sections through two variants of the radiant heater according to the invention, FIG. 22 and 25 are a partial plan of these radiant heaters and the like. 23 and 26 vertical partial cross-sections along the cross-sections III and

VI, looking in the direction of the arrow.

In the embodiments shown, as well as in the following, FIG. 1, there are the following components; In the flat sheet cup 12 there is insulation 13, on which a ring 14 of slightly more solid insulation material is placed in the edge region, such as layer 13, and which fits on the underside of the glass ceramic plate. The radiant heater 11 heats through this glass ceramic hob 15 on the cooking vessel 16 thereon. A temperature limiter 17 with a rod temperature sensor 18 extends beyond the heated area of the radiant heater and contains switches 19 affecting supply in its outside of the bowl 12. with the flow of the radiant heater and eventually disconnect the partial heating elements.

These elements will be given the same reference numbers in the other embodiments and will not be re-described.

In the embodiment of FIG. 1 and 2, there are three bright emitters 20, which are formed as flat halogen lamps containing a tungsten filament contained in a quartz glass tube in a halogen atmosphere and supported by intermediate supports. Such emitters are described in British Patent 1 73 023, to which we refer. Their filament operates at temperatures of the order of 2400 K (2700 ° C) and produces, in addition to the fraction of infrared light, a high proportion of visible light in the white region. The glass ceramic plate 15 is adapted to at least partially transmit this spectral region, while some of the heat is stopped in the glass ceramic plate and is emitted therefrom by contact, etc. to the hob 16. Light emitters 20 have connectors 21 on each side, extending beyond the edge 22 of the sheet metal 12 to the outside and connected therewith to the corresponding connection conductors. The three light emitters 20 extend their edges through the edge 14 and are located with their radiant region within the heated surface 23 of the circular radiator heater, which is formed in the cup interior of the radiant heater. The three radiant radiators extend in parallel and at the same distance across the heated area. Into it are insulated material consisting of striped insulating supports 24, on which the conventional convex heating elements 25 are fastened to the upper side. The dark radiators 25 consist of heating screws made of resistive wire, e.g. Iron-chromium-aluminum alloys used up to temperatures up to about 1500 K (1200 ° C). They are embedded in part into the surface of the insulating supports 24, with the lower part of their bends being spaced at intervals or even the entire length into the insulating carrier prior to its curing. Alternatively, other installation options are also available, e.g. through metal needles, putty and the like.

The strip insulating supports 24 can be positioned between the gaps 26 in which the bright radiators are installed so that the entire heating is approximately one plane, although the bright radiators have a larger outer diameter than the heating screws. In the dotted line drawings, the indicated dark emitters 25 form two dark-emitting heating zones 27 between the three light emitters 20 and may also form one more dark-emitting heating zone 27 on either side of the external light emitters, although this is not always necessary. The heating screws are laid on zipper-shaped insulation supports and their connecting ends are guided outward from the radiator heater in the usual, non-visible manner through the insulating plugs.

In FIG. 3 shows a radiant heater 11 in which it occupies a darkening heating zone 27, which may also be divided into several individually switched heating resistors, a relatively large central area of circular shape, which is surrounded by a circular ring shaped reflective heating zone 28. It houses two bright halogen lamps 20, the radiating area of which is approximately semicircular, while the connecting ends are formed opposite each other and aligned and projected through the edge 14 outwards. The temperature sensor 18 is diametrically and substantially parallel to the connecting ends so as to capture the temperature of the darkening heating zone 27 as best as possible and is less influenced by light emitters.

The embodiments of FIG. 4 to 8 each comprise dark emitters already described on the insulating support 24. 4, two light emitters 20 are mounted on either side of the central, rectangular darkening heating zone 27, so that a rectangular heating field is provided, which is located in the radiant heater on both sides slightly flattened and in the rest with a circularly bounded edge. From the heaters, the circular section-shaped free areas 29 are affected by the light emitters 20 before the edge 14 screens them. The rod temperature sensor 18 of the temperature limiter 17 extends in one direction parallel to the heating zone 27 to one of the light emitters 20 via the heated area 23 and receives from below the radiation of the dark emitters 25 and from the light emitters 20.

FIG. 5 shows an embodiment in which the four bright radiators 20 are arranged parallel to each other in the form of straight bars. Between them, on each of the insulating strips 24, are mounted dark emitters 25, which are connected in series with each other by a connection that runs under the light emitter 20. Each insulating carrier 24 carries two helixes running parallel to each other in parallel. The light emitters are positioned in the gaps 26 between the insulation supports 24 and the temperature sensor 18 of the temperature limiter 17 runs diagonally diagonally across the light emitters and areas of dark emitters.

FIG. 6 shows an embodiment in which four straight, square, square shaped radiant radiators 20 are arranged so that their radiant regions lie within the heated area 23 of the circular radiator heater. The adjacent light emitters are so displaced in height that they intersect in the area of the connecting ends and can thus be connected. The rectangular, preferably square, encircled center region is shaped as a zone of 27 dark radiators and is equipped in a zigzag pattern with conventional heater resistors. The light emitters form the heating zone of the light emitters 28, which surrounds the heating zone 27 of the dark emitters.

In FIG. 7 shows a comparable arrangement in which the three straight bar light emitters 20 are arranged in a right-angled triangle in the same way as in FIG. 6.

The triangular center zone enclosed by them is a heating zone of 27 dark emitters, in which a helix of 25 dark emitters in the form of a spiral is installed. Under light emitters 20, a titanium dioxide coating 59 is applied to the insulating layer 13 to allow a good reflection of the light emitters.

FIG. 8 shows an embodiment in which the light and dark emitters are mounted as in FIG. 4. However, in the center of the heating zone 27 of the dark radiators, a temperature sensor 30 in the form of a circular, flat touch probe, which is mounted in the center, through the radiant heaters through the projecting sleeve 31 from below, and is pressed spring up against the glass ceramic plate. The probe dose 30 is filled with expansion fluid and is connected via a capillary tube 32 with the expansion expansion dose in the temperature sensor not shown. It senses the temperature of the underside of the glass ceramic hob and also receives a feedback from there from the cookware. This is intended for temperature control depending on the temperature and on the value set on the temperature controller, while the existing temperature limiter 17 is also permanently adjusted and switched off only in case of overheating. Its temperature sensor 18 runs diagonally, but due to temperature sensor 30 slightly out-of-center via the heated zone 29. The sensor 30 could also be positioned in the edge region 29, since an even better assembly at the bottom of the cooker 16 is possible there.

FIG. 9 shows the arrangement of the dark emitters 25 on an insulating support 24 having, at places where the light emitter 20 and the temperature limiter 18 of the temperature limiter are mounted, recesses also containing dark emitters such that they pass under the light emitters and the temperature sensor, however, they reduce the mounting height.

FIG. 10 and 11 show the arrangement in which the heating zone of the 27 dark radiators is annularly surrounded by the heating zone of 28 bright radiators. In this embodiment, the light emitter 20a is formed as a meander-shaped strip or wire of molybdenum disilicide-based resistive material, which is mounted in the basic form of a dotted-dotted annular heating zone 28 from light emitters.

The heating element 25 from the dark radiators occupying the heating zone 27 from the dark radiators is divided into two heating resistors 34,35 by a middle branch 33. A central radiator is pre-connected to a bright radiator 20a, which lies with its second pole at terminal 36 of pre-connected switch 37, while the heating resistor 35 is connected to the second terminal 33 of the pre-switch and the heating resistor 34 is connected via a temperature limiter 17 to the output pole 39 of the device for power control 40. Preparation for power control

40 is shown as a clock-working, thermally controlled power steering device with adjusting knob 41 and adjusting shaft 42 and comprising switch 43, preferably a skip switch operated from bimetal 44 heated by control heating 45. The control heating lies in parallel to the radiator heater resistances 11 and on and off with it. The power released, that is, the contribution of the relative switching duration of switch 43, is determined by the adjusting knob 41 and the adjusting shaft 42, which e.g. By adjusting the position of the bimetal relative to the switch 43, it defines the moment and the duration of the switching step by step. On the control side, a power switch 40 is mounted on the power control device 40, which comprises two of the control shaft 42 of the energy regulator controlled switch contacts 46,47, which can connect one pole 48 of the household network during the displayed position in which terminal 38 is contacted. to the position in which terminal 36 is connected to pole 48. In this position it connects contact 46 to conductor branch 49, which is split off from conductor branch 50 and runs between the heating resistor 34 and the temperature limiter 17 to contact 38.

This enables the following operating mode: When the power steering is turned on at full power (100% ED - relative switching time), the tact switch 43 of the power steering device is closed via the adjusting shaft 42 and does not even open when the bimetal is heated. 44 with control heating 45. Contact 47 of pre-switch 37 connects the light emitter 20a to pole 48 of the household network, while the second pole 51 of the household network is connected via a closed switch 43 and then a closed switch of temperature limiter 17 as well as bypass contact 46, conductor 49 and terminals 38 to both heating resistors 34.35 of the dark emitter, which, on the other hand, are connected to the bright emitter 22a via a center turn 33. In this position, therefore, both conventional heating resistors 34.35 are connected in parallel, but in series with the light emitter 20. The light emitter has a very low resistance in the cold state, so that the heat resistors 34.35 are used as impedances and keep the switching current low . As the temperature of the bright emitter 20a increases, its resistance increases and the resistance ratio of conventional heating resistors 34.35 will be lower. Thus, both heating zones 27,28 are heated, but with the dominance of the zone of 28 light emitters, which shows the user that rapid heating is taking place in the circular area covered.

If this activation is maintained, then all the power can be disconnected with the temperature limiter 17 before the glass ceramic plate overheats.

If it switches to a lower heating level, which can start at 100% or e.g. only at 70% ED, then the contact from terminal 36 to 38 is automatically shifted in pre-switch 37 and contact 46 is released. This switches the light emitter 20 off and the two 34.35 heating resistors in a row. In this lower power position, they are clocked and supplied with power, releasing the power setting to 100% only 70% of the total power as they lie in series. This makes it possible to adjust the particularly low power value to a repeatable size of 4%.

FIG. 12 shows a circuit in which the radiant heater 11 has a light emitter 20 and a dark emitter 25. Both are unilaterally locked via a temperature limiter 17 and a power control switch 40 corresponding to that of FIG. 11, halfway through the network 51.

The second light emitter connector 20 is connected to contact 36a of pre-switch 37a, which after installation and operation is identical to pre-switch 37 according to FIG. 11, which uses only one switch contact 47a, which is connected to the pole 48 and the other side of the dark emitter 25. In this embodiment, a light emitter is switched on at the start-up phase, that is, with the power regulator 40 connected to continuous operation. 20 in parallel to the conventional heating resistor 25 and both are controlled jointly by the temperature limiter 17. When setting the power below the maximum power setting, contact 47a opens and the dark emitter 25 is self-controlled in tact from the power control device. In the embodiment of FIG. 15, in the same embodiment of the radiator heater with resistors 20,25, the circuit in pre-connected switch 37a is made by switching the pole of the network 48 from the contact 36a to the contact 38a and connecting to the network therewith or only a light emitter 20 or a dark emitter 25, wherein there is also a power supply in tact, that is, the partial power is supplied only from the dark emitter 25. In the embodiments of FIG. 11, 12 and 15, therefore, the light emitter is connected only when operating at full power or. at the beginning of cooking or baking and partial power are supplied by dark radiators. This does not require the light emitter with its high switching current to be clocked, which in turn may confuse the operator.

The embodiment of FIG. 13 has the same power control device 40 with pre-connected switch 37a as FIG. 12 and is, with one exception, equally tied. The dark emitter 25 is divided in the radiator into two partial resistors 34,35, one of which is connected between the pole of the network 48 and the branch 50 coming from the pole of the network 51 via a power switch 43 and a temperature limiter 17, while the other connected between the pole of the network 48 and the illuminating emitter 20, between which a connecting conductor leads to contact 36a. Here, at full power setting (contact 47a is closed), the light emitter 20 and part of the heating resistor 34 are operated in parallel, while in the setting of partial power (contact 47a is open) the light emitter 20 is pre-coupled with a partial resistor 35, so that the light emitter in with its power and with light effect it stifles in the same tact.

This, on the one hand, saves the light emitter and reduces the load by clocking and, on the other, confuses the light effect, which dampens.

FIG. 14 has the same power control device 40 with pre-connected switch 37a, and the radiator heater 11 has a single light emitter 20 (or several light emitters in parallel or in series, which are tied together) and a dark emitter 25 to which the same applies. They are bound so that when the contact 47a is open and the tact switch 43 and the temperature limiter 17 are closed in series, so that the dark emitter 25 is used as a pre-emptor for the light emitter 20. This is the degree of partial power in which, as in Fig. . 13, the light emitter in the power and light effect suffocates while operating at the closed contact 47a, that is, to start cooking at full power, the light emitter 20 alone with full power.

It can be seen that in particular in FIG. 12 to 15 each use the same control element consisting of a power control device 40 and a pre-connected switch 37a for as many different circuits as possible, so that not only different combinations of light and dark radiators but also other cooking appliances operate with the same control device, e.g. lite hobs or conventional radiators with a cooking start rate. Due to the compatibility of the different cooking options and the possibility of a puzzle system between the controls and the hobs, this is important. In most variants, only three connections are required between the control unit and the hob 11, and a radiant heater is used, which must take care of only a portion of the power as a light emitter without sacrificing the effect of a bright emitter and a fast heating time, and small additional power supply when disconnected. Most devices (especially Figs. 12 and 13) provide a simplified 3θ0 volt design and can be performed with low construction height.

FIG. 16 and 17 show two types of radiation heater arrangement, each having four heating resistors, and which is activated by a self-known, non-displayed seven-stroke switch connected to the radiation heater via four connection leads.

The letters a through f for individual partial images indicate the switching stages from full power (a) to minimum partial power (f). The predicted power of each heating resistor in watts is given each time by the partial figure a and the total power output from the circuit in addition to the figure. We explicitly refer to this. The heating resistors that are in operation each time are marked with a screwdriver, and the width of the screwdriver is indicated if they are operated due to the series connection with reduced power.

In FIG. 16 provides only one dark emitter 25 and three light emitters 20. At full power (a), all are in parallel connected in operation, while in stages b, c and dv there are three, two and one light emitters each with their intended power. At stage e, two bright emitters are connected in series to two parallel illuminator lights, while at the lowest position f of this circuit e a dark emitter is connected in series 25. This gives priority to having at least one bright emitter in all operating positions and that the operator can select the power level from the configuration and intensity light.

In addition, a standard seven-stroke switch can be used, as commercially available for other hobs.

FIG. 17 uses the same seven-stroke switch at the same switching stages, which are also apparent from the fully-fledged terminals. The difference is that only two light emitters 20 are used and for the dark emitter 25 two partial resistors 34.35. In addition, a diode 55 is provided which is bridged by switch 56 in positions a through e. This circuit operates accordingly in FIG. 16 except that none of the light emitters is included in power stage d, but only a conventional heating resistor 34. According to FIG. 16, only one of the light emitters 20 must be replaced by a resistor 34. In the lowest position f, switch 56 is unlocked and diode 55 halves the power once more, so that the minimum 93 watts rate is only about 5% of the total installed power, and s thus a possible degree of heat retention.

If the commercial conventional seven-stroke switch is not used, then the configuration of FIG. 17 creates a design with five independently-inclusive terminals, in which the diode is redundant, because then the low-power output of all four radiators can then be produced. There would also be a "dark" position d. The fact that dark radiators are used in addition to light emitters not only save on expensive light emitters and improved controllability, but also ensures that light emitters are not too strong due to light emitters and, especially in tact given power, the power surges are somewhat damped in their effect on the substance being cooked, which would be disruptive in the second case due to the small subsequent heat supply to the light emitters.

FIG. 18 and 19 show a radiator heater 11 of the type described above with two parallel illuminators 20 in position, spaced about half the diameter of the radiator heater, and containing each other in the remaining segment of the dark radiator circle 25. The straight tubes of the bright radiator extend from the edge to the edge of the radiator heater 11. The straight rod temperature sensor 18 of the temperature limiter 17 runs approximately centrally between the light emitters 20 and parallel to it through the central heating zone of the dark emitters 27.

For temperature control, in addition to the edge of the radiator heater, a temperature sensor 60 is mounted in the form of a flat touch probe filled with expansion fluid. It is pressed through a flexible latching mechanism 61 and therein is a pressure spring located on the underside over the edge of the heater 22 of the extending section 63 of the sheet of the conveying heat transfer element 64. This is mounted by means of a socket attachment 65 consisting of bent sheet metal tongues, at the upper edge of the can 12 and extends between the edge 22 and the underside of the hob 15 through a heated area 23, partially overlapping it in a lenticular, marginal region 66. The arrangement of the projections 67 provides increased strength there. In the inner region 66 and the edge region 22, the heat transfer element is placed flat on the hob and is heated from below by the radiation of the dark radiators in which it lies, in the same way as the hob 15, but also receives a certain but very limited fraction of radiation from of light emitters, so that, in the first place, the temperature of the dark emitters is important for temperature control and a certain feedback effect from the hob and from the hob. The temperature sensor is located in the outer area protected from high temperature and nevertheless has a good access through the heat transfer element. Preferably, the heat transfer element consists of a sheet of iron, which is on the side facing the cooking surface, clad with about the same strong aluminum layer and contains a very thin aluminum cladding on the opposite side. For further details of this sensor arrangement, we refer expressly to the second publication of European patent 00 21 107 and to the German utility model 81 09 131 (= British first publication 20 95 834).

FIG. 18 shows a temperature controller 69 connected via a capillary tube 68 to a temperature sensor 60, the circuit and function of which will be explained on the basis of FIG. 20,

- 23, with reference to further details, referring explicitly to German third publication 28 50 389 (= British second publication 20 40 574). The temperature controller 69 includes an expansion box 70 connected to the capillary tube 68 to which an expansion space 71 is further connected, which is mounted in the air space parallel to the controller housing and is heated by the control heating 73. Double skip switch 72 (or two parallel skip switches) ) is operated from the expansion dose under simultaneous influence with the adjusting screw spindle 74. The pre-switching unit 75, which is mechanically mounted on the temperature controller 69 and through which the adjusting shaft 74 extends and is operated, contains a mechanical auxiliary switch 76, which is closed only at setting the maximum control temperature or. in her field. This further plugs in the two light emitters 20, which then, like the dark emitters 25, which are not affected by the additional switch 76, are switched on and off at a temperature controlled by contact 77. The second contact 78 of the temperature controller connects control heating only at temperature values close to but below the control temperature, but each time only with a dark emitter. This creates a clock-working temperature controller whose operation during the stroke is switched off during the heating phase and is only connected to the rated temperature, shortly before reaching that temperature automatically with the expansion member 70. allowing the specified temperature controller to deviate substantially from the nominal temperature due to its operation in clock speed. It's a regulator

- 24 is therefore particularly suitable for glass ceramic panels and especially for the described installation of the temperature sensor.

In the example shown, the temperature limiter 17 is included in the common supply of all the heaters and can therefore disconnect the total supply.

The arrangement of the temperature sensor described above and the installation of the light emitters described below cannot be used with priority only for radiant heaters with a combination of light and dark emitters, but also for radiant heaters containing only light emitters.

FIG. 21 to 23 show a radiant heater 11, which is located below the cooking surface 15, consisting of glass ceramics. This heats the hob 15 from below and thus forms a hob where the hobs can be heated.

The radiant heater 11 comprises an insulating support 24, which is shaped in a bowl and lies in a sheet metal cup. On the edge 22 of a high temperature resistant insulating support consisting of relatively well insulated material, a ring shaped shutter 114 is mounted with respect to a denser and more solid, but also temperature resistant and insulating material, with its internal insulating support 24 the corner protrudes slightly inwardly through the inner corner 80 of the edge 22. The overlay aperture rests with its upper face on the lower cooking surface 15 and is typically pressed against it by a spring force acting on the sheet metal cup 12.

- 25 Because normal material with high thermal insulation ability, which is not mechanically very rigid, is used for insulating support 24, special damage may occur in the edge area, which is particularly stressed during production and assembly, in the area of the unprotected inner corner 80 edge 22, which could lead to the use of light-emitting heating elements 22 as described in the following, to an optical image with a torn edge that would deviate from the basic shape (especially the circular shape) of the hob. This is prevented by a sharp limitation of the edge, especially at the inwardly projecting inner corner 81. The penetration of visible radiation through the recesses formed in the soft edge, and thus the conditioned illumination outside the cooking surface of the lying area of the entire cooking device 100, is thereby prevented. It further protects the overlay aperture 114 of the edge of the insulating body against other mechanical influences.

In the embodiment, there are provided two light-reflecting heating elements 20, which may also be referred to as high-temperature radiant heaters and consisting of, as described above, a high-temperature closed helix 83 enclosed in a silicon balloon 82, which emits radiation far in sight and operates at temperatures well above 1500 K (approximately 1200 ° C).

These are in the form of extended bars or soffits, which have a flat section 84 at their ends, from which the connecting ends 21 project and protrude there with the connecting leads. In the example, two illuminating radiators 20 are installed in parallel and with a spacing corresponding to about half the diameter of the radiator heater. Between them and between the edges 22 is the formed area of circular sections inside the radiator heater formed

- 26 of the heated area 23, dark radiant heating elements 25 are installed, consisting of heating screws of conventional resistive materials used for radiant heaters, e.g. made of iron-chromalumini j alloy, which can be used up to temperatures of approximately 1500 K (1200 ° C) without complete enclosure or a shielding gas atmosphere.

These heating screws are arranged generally helically in a shape adapted to the shape of the respective radiator zone of the dark emitter 27 and secured by partial insertion into the material of the insulating carrier, e.g. 27 29 929. Under the light emitter 20, the insulating support, in the distance from the light emitter 20, may take the form of a flat, curved groove 85, in order to achieve a directional reflection of the radiation. Light emitters and dark emitters are switched on with selector switches, controls or. power or temperature controls in parallel, sequentially or individually, with the light emitters included specifically in the cooking start area. in the higher power range because they can show their best there advantages of rapid heating with relatively low inertia.

FIG. 22 and 23 show that the ends of the light emitters 20 lie in the edge bores 86, which are adapted to the shape of the light emitter tube and narrow to the outer opening 87 formed to receive the flattened connecting end 84 of the light emitter. This flattened end stands here at right angles, so that in the marginal cavity 86,87 the light emitter is guided in the transverse and longitudinal directions. The edge outline is provided in FIG. 21 to 23 in edge 22 and is open upward. The overlay aperture 81 covers the opening of the edge cavity and thereby slides it upwards so that it is not visible from above. The part of the end sections 90 of the light emitter 20, comprising the flat section 84 and also the non-intruding tube of the light emitter, adjacent thereto, extends in part with the flat section 84 from the outer opening 87 and is electrically connected there. With these flattened or flat-pressed end sections 84, relatively large amount of light exits from the outside of the radiator heater 88 of the cooking appliance 100 and this would illuminate the interior of the glass-ceramic sink. As this is not only optically unattractive, it can also lead to the unacceptable heating of the outer region 88 and to the thermal compromise of the connecting conductors or switchgear, the end section and the particularly flattened section 84 are coated with light absorbent or light absorbent. reflecting layer 89, which also covers in particular the end faces 91 of section 84. This layer could work e.g. reflecting inwardly and acting outwards for the radiation affected here in black and would exist under given conditions from two layers placed over each other, e.g. deposited metal layers and layers of heat-resistant lacquer mounted over it, also used for painting hotplates. The layer 89 should cover at least an area extending from the outer opening 87 into the space 88, and further areas of the end section 90 may be covered in order to protect the edge-hole region 86,87 preferably from direct radiation. As a very desirable side effect, the temperature in section 84 may be lowered, which is highly desirable because the critical point of the halogen radiators is the temperature at the compressed site through which the conduit connection 21 is externally. If this temperature rises too high, it would be due to oxidation phenomena

- 28 the leakage of the lamp is compromised in the conductive position.

The embodiment of FIG. 24 to 26 corresponds to that of FIG. 21 to 23 except for the following differences: The overlay sheet 1l4a consists of a relatively thick ring having an almost square cross-section. Also, this extends with its inner corner 81 through the inner corner 80 of the edge 22 of the insulating carrier 24. The edge bores for the two end sections of the light emitter 20 are each divided into two sections, of which section 86a lies in the area of the insulating carrier 24, while section 86b in aperture region 114a is mounted. The same, mainly central, two-part division applies to the outer aperture 87, to the flattened section 84, so that by mounting the aperture 1l4a to the edge 22, the illuminating radiator 20 is securely fixed. Here, too, a flat section 84 protrudes, with most of its length from the outer opening 87 outwards. In this area there is overlap 92, which is formed as a nozzle on the overlay sheet 1l4a and partly surrounds the end section with a good upward spacing, on both sides and in the area of the front face. The screening of the front surface 91 is particularly important because the radiation there exits is particularly intense than from the light guide. The edges 93 of the overlap 92 surrounding the end section 84 extend in the example shown to the lower plane of the overlay aperture 1l4a and thereby to the center plane of the light emitter. However, this dividing plane can also be moved further upwards or preferably downwards with respect to the bright emitter to further cover the final section 90 with the edge 93. It is important that the spacing at which the end of the bright emitter is surrounded is possible from there. heat dissipation and overheating of the end is prevented.

- 29 Particularly preferred is the combination of both embodiments with overlay 92 and layer 89.

When constructing an overlay aperture with overlap 92, care must be taken to ensure that the special overlay 92 is as impermeable to light as possible, which can be accomplished, on the one hand, by a special thickening of the material, e.g. ceramic fiber made of aluminum, commonly known as Fiberfax, or with a light-tight coating or both. Since light opacity is also desirable for the overlay aperture, this purpose can also be achieved by appropriate coloration or selection of an absorbent binder. The material of the overlay orifice should be cemented with mineral binders to give a precise, optical edge of the hob to the defining corner. By arranging that only the flattened end portion extends through the outer opening 87, a large portion of the light exiting is already visible in the edge region 86. It would also be possible to project outwards the entire flattened section 84, although by extending it to the edge the possibility of reliable control of the halogen bulb, even against rotation, eg. important when the light emitter itself has a reflective layer on the outside or inside of its balloon 82. It is also advantageous that the installation according to the invention can save demanding end sockets. Due to the radiation conditions from the end sections of the light emitters 90, the edge 93 of the overlap 92 is particularly important because it retains the bulk of unwanted radiation. It would also be possible to create an overlay from the insulating material

- 30 of the carrier 24, provided that adequate thickening and light impermeability are ensured with sufficient ventilation of the end. However, it would also be possible to provide overlapping parts on the ring and insulating support, which are in e.g. they are so different in size that they overlap, but leave a sufficient gap for ventilation. This would create a labyrinth-like overlay that practically does not allow any light to escape. In practice, therefore, it may be envisaged, e.g. on the insulating support, the overlap in basic form in FIG. 25 shows the overlay 92, while the overlay sheet 114 is provided with a particular overlap formed by its edge and extends beyond the gap provided below.

PATENT APPLICATIONS

1. A radiator for cooking appliances with a hob, specially designed as a ceramic glass hob 15, with at least one electric light-emitting heating element 20,20a, operable at a temperature above 1500 K (about 1200 ° C) and having a radiation spectrum extends significantly into the field of vision, characterized in that the radiant heater (11), with the exception of at least one bright radiator (20,20a), has at least one heating zone (27) with a dark radiation operative at temperatures below 1500 K (ca. 1200 ° C). a heating element (25) which can be switched on simultaneously and / or alternately with a bright radiator (20,20a).

2. A radiant heater according to claim 1, characterized in that the light emitter (20a) consists of a resist material based on molybdenum disilicide (MoSi ₂ ).

Radiant heater according to claim 1 or 2, characterized in that at least one dark radiator (25) is connected in succession during operation of the light emitter (20,20a), provided especially only in the upper power range for cooking and baking. , whereas, preferably, only the dark radiators (25) are included in the lower power range for continued cooking, the pulse-controlled power control device (40) operating under the conditions under the given conditions.

Radiant heater according to one of the preceding claims, characterized in that two dark emitters (34,35) are provided which are pre-connected to the light emitter (20,20a) in parallel

- 32 bindings, which in turn are included in the sequence in the field of power to continue cooking.

Radiant heater according to one of the preceding claims, characterized in that the radiant heaters (25) are self-contained in the center portion of the radiant heater (11), which is surrounded by a annular region (28) in which the radiant radiator (20) is located. , 20a), preferably with straight light emitters (20) arranged in a polygonal shape around the dark-emitting heating zones (27).

Radiant heater according to one of the preceding claims, characterized in that, between the light emitters extending in a straight line through the preferably approximately circularly heated area (23) of the radiator heater (11) and preferably consisting of halogen lamps, they are arranged with dark emitters (25 ) heating zones (27) are provided, preferably with light emitters (20) located in the gap region (26) or recesses between the insulating supports (24) carrying the dark emitters (25).

Radiant heater according to one of the preceding claims, characterized in that the dark radiators (25) are secured by partial insertion on strip or plate shaped insulating supports (24), which are arranged in parallel between the bright radiators (20).

8. Heater according to ^- one of the preceding claims, characterized in that the rod-like temperature sensor of the temperature limiter (17) is arranged preferably parallel to the clear sevalniku (20) additionally over the dark radiant heating zone (27).

Radiant heater according to one of the preceding claims, characterized in that the temperature radiator (17) disconnects the dark radiators (25), leaving the bright radiators (20,20a) as residual power.

Radiant heater according to any one of the preceding claims, characterized in that the temperature switch with a suitable start cooking temperature is set to a temperature and such a large switch delay that it does not switch on again after switching off the radiator (11) before being switched on before the bright radiator (20,20a).

Radiant heater according to one of the preceding claims, characterized in that the power control device (40) in operation is provided with an additional switch (37,37a) which can be manually operated via the adjusting shaft (42) of the control device which is preferably contained in a pre-connected switch and includes at least one bright emitter in the upper power range, especially when adjusting the power of the power steering device (40) with a 100% relative switch-on duration.

Radiant heater according to one of the preceding claims, characterized in that in the middle and lower power ranges, the sequential coupling of light and dark radiators (20,25) is provided with a power control device (40) with a voltage in tact.

Radiant heater according to one of the preceding claims, characterized in that the power of the radiant heater (11) with multiple light emitters (20) and at least one dark emitter (25,34,35) is controlled in parallel, single and sequential binding of the radiators via a multi-stroke circuit, preferably a seven-stroke circuit.

34 Radiant heater, in particular according to one of the preceding claims, characterized in that it is assigned a temperature sensor (60) of the temperature controller (69), which operates in a cycle with a regulated relative switching duration and is provided with a control in the given conditions heating (73), wherein the temperature regulator (69) regulates the dark emitters (25) and is assigned an additional switch (76), preferably in the form of a temperature controller (69) of a mounted pre-connected switch (75), which can be operated together by setting it and connecting a bright emitter at or near the highest control temperature.

Radiant heater according to claim 14, characterized in that all the light emitters (20) can be connected with an additional switch (76), and that preferably the light emitters (20) and the dark emitters (25) can be controlled in tact contacts (77) of the temperature controller (69).

Radiant heater, in particular according to one of the preceding claims, characterized in that the temperature sensor (60) is provided with a sheet-shaped heat transfer element (64) which covers a section of at least one dark in the edge region of the radiant heater (11). the radiator (25), which is positioned between it and the cooking surface (15) with contact with it, and that the temperature sensor, preferably formed as a touch probe (60), is filled with expansion fluid located outside the radiator heater (11) in thermal contact with by the heat transfer element (64).

- 35 17. A radiation heater, in particular according to one of the preceding claims, characterized in that it has a pre-radiation screen (89,92,93,114,1I4a) in the edge region of the radiant heater (11).

Radiant heater according to claim 17, characterized in that it shields the screen before radiation (89,92,93) of the final sections of the light emitter (20) against the area of the cooking device (100), which lies outside the radiator heater (11).

Radiant heater according to claim 17 or 18, characterized in that the edge (22) of the insulating body (24) of the radiant heater (11) is covered by a radiation screen, preferably formed as a substantially annular insulating overlay aperture (114, 1l4a). , facing the cooking surface (15), comprising a particularly overlapping aperture (1l4,1l4a) of higher-strength insulation material and, under the given conditions, a density than the insulating body (24) placed below it to be made of a high temperature-resistant thermal insulation masses equipped with mineral binders and projecting preferably at its preferably sharply circumscribed inner circumference (81) over the corresponding inner circumference (80) of the insulation body (24) and having a relatively low height especially in relation to the ring width.

Radiant heater according to one of the preceding claims, characterized in that at least one end portion of the light-reflecting heating element (20) which lies in the edge cavity is provided with a layer (89) which forms a radiation shielding and absorbs and / or reflects light, largely covering the face of the light emitter (91).

Radiant heater according to one of the preceding claims, characterized in that at least one end section (90) of the light-reflecting heating element (20) is surrounded upwards and at least partially laterally and in the region of the end face (91) of the end section (90) with an overlay (92) that connects to the edge cavity (86,87) and forms a radiation shield, the overlay (92) being preferably part of the thermal insulation (24,114,1I4a) of the radiator heater (11), at least a portion of the overlap (92) is provided on the overlay diaphragm (1l4a) and the overlapping orifice (1l4a) may comprise at least a portion of the edge bore (86b), the overlay (92) preferably facing the cooking surface (15) facing and in days conditions also part of the end section (90) of the light-emitting heating element (20), the circulating edge (93) and is open downwards.

Radiant heater according to one of the preceding claims, characterized in that the edge cavity (86,87) is provided in the edge (22) of the insulating body (24) and is preferably open upwards.

Radiant heater according to one of the preceding claims, characterized in that the overlay (92) surrounds at least a portion of the section of the light-emitting heating element (84) therein.

Radiant heater according to any one of the preceding claims, characterized in that the cross-sectional, particularly flattened section (84) extends at the end of the reflective heating element through an appropriately shaped slit to open an opening (87) of the edge bore (86).

For

19356-IX-85-MS

E.G.O. Electro-GerSte Blanc u. Fischer:

Claims (1)

SUMMARY Radiant heater for cooking appliances A glass ceramic hob heating radiator 11 contains electrical heating resistors of two types: dark radiators 25 in the form of a helix coiled winding resistor wire operating at a lower temperature, and bright radiators 20 with a high radiant temperature in the light region, which may be formed e.g. with halogen lamps. Dark emitters 25 can be switched on before bright emitters 20 to reduce high switching currents on the one hand and to make regulation easier and less complicated for the user. Alternatively to halogen light emitters, molybdenum disilicide (MoSi ₂ ) may also be used. Control circuits are proposed with active power control devices and multi-stroke switches. To this fig. 1