EP2312212B1 - Gas hotplate with dual circuit burner - Google Patents

Description

The invention relates to a gas hob with a gas burner, which comprises an internal burner and at least one external burner, and a gas supply unit according to the preamble of one of the independent claims 1 or 6.

The gas burner of the generic gas hob has an internal burner and an external burner, which are supplied separately from each other with gas. Such gas burners are also referred to as two-circuit burners. A gas supply unit, which usually comprises a mechanically or electrically actuable gas valve, controls the gas flow to the internal burner and the external burner of the gas burner in dependence on the specification by an operator by means of a suitable operating element. As a control element is, for example, a mechanically operable rotary knob, but also an electronic user interface, such as a plus / minus button or a touch slider into consideration.

Compared to conventional gas burners with only one burner ring, the ratio between the highest possible burner output and the lowest possible burner output is considerably greater for a dual-circuit burner. For this purpose, in the two-circuit burner, a first power range is defined with low burner power, in which only the gas flow to the internal burner is open. Usually, within the first power range, the gas flow to the internal burner can be varied between a minimum value and a maximum value.

In a second power range of the two-circuit burner, the gas flow is opened to the outer burner. Within the second power range, burner power adjustment is usually accomplished by varying the gas flow to the outside burner between a minimum and a maximum value. The gas flow to the internal burner is set to the maximum value.

From the WO 2008/141916 A2 For example, a gas hob is known which has a gas burner comprising an internal burner and an external burner. A gas supply unit designed as a gas tap is embodied such that in a first power range of the gas burner the gas flow to the internal burner is at least temporarily open and the gas flow to the outside burner is interrupted. In a second power range of the gas burner, the gas flow is continuously opened to both the inner burner and the outer burner and is varied between a minimum value and a maximum value for adjusting the burner output.

In generic gas hobs of the prior art, the transition from the first power range to the second power range of the Gas burner to a power leap. For the operator of the gas hob, this power jump occurs unexpectedly, as it is neither traceable or predictable based on the deflection of a mechanical control element, nor on the basis of the switching stages of an electronic user interface.

The present invention has for its object to provide a generic gas hob available, which has a continuous performance as possible.

A first solution of this object according to the invention provides that the gas supply unit is designed such that in the second power range of the gas burner for adjusting the burner output, the gas flow to the internal burner is additionally varied between a minimum value and a maximum value. This adjusts the burner output in the second power range both via the internal burner and via the external burner. This enables a particularly differentiated setting of the burner output, in particular with a small burner output within the second power range.

Thus, at the smallest burner output within the second power range, the gas flow to the inner burner is smaller than at the largest burner output within the first power range. For example, at the smallest burner power within the second power range, the gas flow to the internal burner may be set to a minimum value. At the same time, if the gas flow to the outside burner is also set to a minimum value, the total power of the gas burner is only slightly higher than the maximum burner power within the first power range, if the gas flow to the internal burner is at a maximum and the gas flow to the outside burner is interrupted.

With an average burner power within the second power range, the gas flow to the internal burner is set to the maximum value. The same applies to a high burner output within the second power range. The adjustability of the gas flow to the internal burner is only within the second power range used to minimize the smallest burner power within the second power range.

In addition, the gas supply unit may be designed such that, at least at a certain burner power within the second power range of the gas burner, in particular at the smallest burner power within the second power range, the gas flow to the outer burner is timed. By cycling the gas flow, the average power of the gas burner averaged over time can be further reduced. This can be used within the second power range of the gas burner to set the minimum power to a particularly small value.

For adjusting the burner output within the second power range, the clock ratio between the switch-on time and the switch-off time of the gas flow to the external burner is variable.

According to the invention, the object mentioned at the outset is likewise achieved in that the gas supply unit is designed such that the gas flow to the outer burner is timed at least at the smallest burner output within the second power range of the gas burner. The average power of the gas burner, averaged over time, can be set to particularly low values by cycling the outer burner. The internal burner burns continuously and can be set to a constant power value.

At a medium and / or high burner power within the second power range, the gas flow to the outer burner is continuously opened. A clocking of the outer burner is thus only at low burner power within the second power range.

At least at the lowest burner power within the second power range, the open gas flow to the outer burner is set to the minimum value. The lowest power level within the second power range of the gas burner provides that the gas flow is clocked to the outer burner and also on the Minimum value is set. By changing the duty cycle between on and off time of the outer burner while the burner power can be varied. The next power stage provides that the outer burner burns continuously with a minimum value of the gas flow. To further increase the power output, the gas flow to the outer burner can be increased stepwise up to a maximum value.

Within the second power range, the gas flow to the internal burner is continuously opened. The flames on the inner burner can then be used, for example, to ignite the outer burner when it is operated in clock mode.

Within the second power range, the opened gas flow to the internal burner is set to a constant value, preferably to a maximum value. The power control in the second power range then takes place completely by means of the outer burner.

For adjusting the burner power within the second power range, the duty cycle between on-time and off-time of the outer burner is variable. The burner averaged over time can be adjusted in this way.

In both o. G. Solutions of the object set out, it is advantageous if in the first power range of the gas burner, the opened gas flow is varied to the internal burner between a minimum value and a maximum value. In the first power range, the power setting thus takes place by adjusting the flame size on the internal burner.

Alternatively or additionally, the gas supply unit may be designed such that a low-power region of the gas burner is provided, in which the gas flow to the internal burner is timed and the gas flow to the external burner is interrupted. It is possible to perform the first power range of the gas burner as a low power range. The power setting then takes place in the first power range exclusively by changing the clock ratio between the on-time and off time of the gas burner, while the flame size is set to a constant value during the switch-on. Of the Low-power range can also be provided in addition to the first power range of the gas burner. In this case, in the first power range, the burner output is adjusted by varying the gas flow to the constantly burning internal burner. Even lower performance of the gas burner are achieved in the low power range by the inner burner is clocked at the lowest flame.

For adjusting the burner output within the low power range, the duty cycle between on time and off time of the indoor burner is variable.

Within the low power range, the gas flow to the internal burner is set to the minimum value.

Figur 1

einen Zweikreisbrenner mit einem Innenbrenner und einem Außenbrenner,

Figur 2

eine Gasversorgungsschaltung,

Figur 3

die Leistungskennlinie des Gasbrenners gemäß dem Stand der Technik,

Figur 4

die Leistungskennlinie des Gasbrenners in einer erfindungsgemäßen Gaskochstelle,

Figur 5

die Leistungsstufen des Gasbrenners gemäß einer ersten Ausführung der Erfindung,

Figur 6

die Leistungsstufen des Gasbrenners gemäß einer zweiten Ausführung der Erfindung.

Further advantages and details of the invention will be explained in more detail with reference to the embodiments illustrated in the schematic figures. It shows

FIG. 1

a dual-circuit burner with an internal burner and an external burner,

FIG. 2

a gas supply circuit,

FIG. 3

the performance characteristic of the gas burner according to the prior art,

FIG. 4

the performance characteristic of the gas burner in a gas hob according to the invention,

FIG. 5

the performance levels of the gas burner according to a first embodiment of the invention,

FIG. 6

the performance levels of the gas burner according to a second embodiment of the invention.

In FIG. 1 is shown as a two-circuit burner gas burner 1 is shown. The gas burner 1 comprises an outer burner 2 with gas outlet openings 3 and an inner burner 4 with gas outlet openings 5. The outer burner 2 and the inner burner 4 can be supplied with gas independently of each other.

A gas supply unit 14 provided for this purpose is in FIG. 2 shown. The gas supply unit 14 comprises a main gas line 6, in which a main gas valve 7 is arranged. From the main gas line 6 branches off behind the main gas valve 7, a branch line 8 to the outer burner 2 and a branch line 9 to the inner burner 4 from. In each of the branch lines 8, 9 is an open-close valve 10, which may be embodied for example as a solenoid valve, and a control valve 11. With the control valve 11, the opening cross section of the respective branch line 8, 9 and thus the size of the gas flow to External burner 2 or the internal burner 4 are continuously or multi-stage set. The control valves 11 can be driven, for example, by means of a respective stepping motor. In addition to adjusting the opening cross section in each of the branch lines 8, 9, it is also possible to clock the gas flow in the branch lines 8 and / or 9. This means that the gas flow to the outer burner 2 and to the inner burner 4 is intermittently completely interrupted and reopened. This can be done, for example, by periodically opening and closing the on-off valve 10 or by periodically opening and closing the control valve 11 in the corresponding branch line 8, 9. The control of the main gas valve 7 and the open-close valves 10 and the control valves 11 by means of a preferably electronic control 12, which is connected via control lines 13 to the valves 7, 10, 11.

In FIG. 3 the performance curve of a gas burner 1 in a gas hob of the prior art is shown. Plotted on the right-hand side of the diagram are the power levels that can be selected by an operator at an appropriate user interface. As a user interface, for example, a latched rotary knob, plus / minus buttons or a slider into consideration. The power output of the gas burner 1 is plotted on the vertical axis of the diagram. The power curve comprises three areas, a low power area 20, a first power region 21 and a second power region 22.

In the diagram viewed from left to right, the adjustment range of the gas burner 1 begins with the low-power region 20, in which the gas flow to the inner burner 4 is timed and the gas flow to the outer burner 2 is interrupted. The different power levels within the low power range 20 are achieved by varying the duty cycle between on time and off time of the indoor burner 4. During the switch-on time of the internal burner 4, the gas flow to the internal burner 4 is set to a minimum value. The minimum value of the gas flow is such that the flames on the internal burner 4 are as small as possible without extinguishing by themselves.

In the first power range 21, the gas flow to the inner burner 4 is continuously opened, while the gas flow to the outer burner 2 is still closed. The different power levels within the first power range 21 are achieved by gradually increasing the gas flow to the internal burner 4 from the minimum value to a maximum value.

In the area of the transition from the first power range 21 to the second power range 22, the outer burner 2 is switched on. The different power levels within the second power range 22 are achieved by varying the gas flow to the outer burner 2 between a minimum value and a maximum value. In gas cooking stations of the prior art burn in the second power range 22, the flames on the outer burner 2 continuously and the gas flow to the inner burner 4 is set constant to the maximum value.

A disadvantage of this performance characteristic of a gas hob of the prior art is that in the region 15 of the transition from the first power region 21 to the second power region 22, a jump in performance arises that may be surprising for the operator of the gas hob. In addition, there is no possibility in region 15 of setting the power output of the gas burner 1 to an intermediate value.

FIG. 4 shows the performance curve of the gas burner 1 of a gas hob according to the invention, in which in the region of the transition between the first power region 21 and the second power region 22, the power curve is continuous and beyond, in comparison to the curve according to FIG. 3 , in this area an intermediate level exists.

The operation of the gas hobs according to the invention is described below with reference to the FIGS. 5 and 6 explained. In these diagrams, the power levels of the gas burner 1 are illustrated by a bar chart. Analogous to the FIGS. 3 and 4 On the right axis, the power levels selectable by the operator with the user interface are plotted, and the power output of the gas burner 1 is plotted on the vertical axis. In the second power region 22 of the gas burner 1, the beams are divided into a lower portion and an upper portion. In this case, the lower section of each bar represents the output of the internal burner 4, the upper section of the bar the output of the external burner 2. A longitudinally dashed bar means that the relevant gas burner 1 is operated in a time-clocked mode. The height of the bar here reflects the power output of the gas burner 1 during its switch-on time. The average power of the gas burner 1, averaged over time, is indicated by a horizontal bar in the area of the relevant bar.

FIG. 5 describes a first preferred embodiment of the invention with reference to the power levels of the gas burner 1. Analogously to the prior art, in the low-power region 20 of the inner burner 4 is operated in timed-clock mode. In the first power range 21, the gas flow to the continuously burning internal burner 4 is gradually increased. In the second power range 22 of the outer burner 2 is switched on and the gas flow to the outer burner 2 increases gradually.

According to the invention, in the first stage 16 of the second power range 22, the gas flow to the internal burner 4 is set to a smaller value than in the remaining stages of the second power range 22. In the present embodiment, the gas flow to the internal burner 4 in the stage 16 is set to a minimum value. Of the Gas flow to the outer burner 2 is also set to a minimum value in the stage 16. In this way, in the stage 16, a total output of the gas burner 1 is achieved, which is greater than the maximum power within the first power range 21 and less than the total power of the gas burner 1 in the power stage 17, in which the gas flow to the internal burner 4 to a Maximum value is set and the gas flow to the outer burner 2 to a minimum value.

FIG. 6 illustrates the second embodiment of the invention, in which in the power stage 16 a comparable overall performance of the gas burner 1 is achieved as in the embodiment according to FIG. 5 in the power stage 16. In the power stage 16a, the gas flow to the internal burner 4 is set to a maximum value. At the same time, the gas flow to the outer burner 2 is set to a minimum value and moreover clocked in time. The cycle ratio between the on-time and the off-time of the outer burner is such that the total output of the gas burner 1 in the power stage 16a is between the highest power in the first power range 21 and the total power of the gas burner 1 in the next higher power level 17.

In both embodiments of the invention, a continuous transition between the first power region 21 and the second power region 22 is ensured with regard to the power output of the gas burner 1. The power difference between the highest power in the first power range 21 and the lowest power in the second power range 22 substantially corresponds to the power difference between two levels within the second power range 22.

An alternative variant of the invention provides to combine the two embodiments of the invention described above and thus to allow both a clocking of the gas flow to the outer burner 2 and a variation of the gas flow to the inner burner 4 in the second power range of the gas burner. It is possible either to clock either the gas flow to the outer burner 2 or to vary the gas flow to the inner burner 4. It is also possible to simultaneously clock the gas flow to the outer burner 2 and to vary the gas flow to the inner burner 4.

LIST OF REFERENCE NUMBERS

1

gas burner

2

external burner

3

Gas outlet openings

4

internal burner

5

Gas outlet openings

6

Main gas line

7

Main gas valve

8th

Branch line to the outside burner

9

Branch line to the internal burner

10

On-off valve

11

control valve

12

control

13

control lines

14

Gas supply unit

15

Area

16a

power stage

17

power stage

20

Low-power range

21

first performance range

22

second power range

Claims (15)

1. Gas hotplate having a gas burner (1) which comprises an inner burner (4) and at least one outer burner (2), and a gas supply unit (14) which is designed such that

   - in a first power range (21) of the gas burner (1) the gas flow to the inner burner (4) is at least temporarily open and the gas flow to the outer burner (2) is interrupted, and that

   - in a second power range (22) of the gas burner (1) the gas flow to the inner burner is continuously open and the gas flow to the outer burner is at least temporarily open and the open gas flow to the outer burner (2) is varied to adjust the burner power between a minimum value and a maximum value,

   in the second power range (22) of the gas burner (1) the gas flow to the inner burner (4) is additionally also varied between a minimum value and a maximum value to adjust the burner power, and that
   the second power range (22) comprises a first power stage (16) and a second power stage (17);
   characterised in that
   the first power range (21) and the second power range (22) merge into one another, and that
   in the first stage (16) the gas flow to the inner burner (4) is adjusted to a smaller value than in other stages of the second power range (22), such that in the first power stage (16) a power output of the gas burner (1) is achieved overall which is greater than a greatest power within the first power range (21) and smaller than an overall power of the gas burner (1) in the second power stage (17).
2. Gas hotplate according to claim 1, characterised in that at the smallest burner power within the second power range (22) the gas flow to the inner burner (4) is smaller than at the greatest burner power within the first power range (21).
3. Gas hotplate according to claim 1 or 2, characterised in that at a mean burner power within the second power range (22) the gas flow to the inner burner (4) is adjusted to the maximum value.
4. Gas hotplate according to one of claims 1 to 3, characterised in that the gas supply unit (14) is designed such that at least at a certain burner power within the second power range (22) of the gas burner (1), in particular at the smallest burner power within the second power range (22), the gas flow to the outer burner (2) is timed.
5. Gas hotplate according to claim 4, characterised in that to adjust the burner power within the second power range (22) the clock ratio between on time and off time of the gas flow to the outer burner (2) is variable.
6. Gas hotplate having a gas burner (1), which comprises an inner burner (4) and at least one outer burner, and a gas supply unit (14) which is designed such that

   - in a first power range (21) of the gas burner (1) the gas flow to the inner burner (4) is at least temporarily open and the gas flow to the outer burner (2) is interrupted, and that

   - in a second power range (22) of the gas burner (1) the gas flow to the outer burner is at least temporarily open and the open gas flow to the outer burner (2) is varied to adjust the burner power between a minimum value and a maximum value,

   characterised in that the gas supply unit (14) is designed such that at least at the smallest burner power within the second power range (22) of the gas burner (1) the gas flow to the outer burner (2) is timed.
7. Gas hotplate according to claim 6, characterised in that at a mean and/or at a high burner power within the second power range (22) the gas flow to the outer burner (2) is continuously open.
8. Gas hotplate according to claim 6 or 7, characterised in that at least at the smallest burner power within the second power range (22) the open gas flow to the outer burner (2) is adjusted to the minimum value.
9. Gas hotplate according to one of claims 6 to 8, characterised in that within the second power range (22) the gas flow to the inner burner (4) is continuously open.
10. Gas hotplate according to one of claims 6 to 9, characterised in that within the second power range (22) the open gas flow to the inner burner (4) is adjusted to a constant value, preferably to a maximum value.
11. Gas hotplate according to one of claims 6 to 10, characterised in that to adjust the burner power within the second power range (22) the clock ratio between on time and off time of the outer burner (2) is variable.
12. Gas hotplate according to one of claims 1 to 11, characterised in that in the first power range (21) of the gas burner (1) the open gas flow to the inner burner (4) is varied between a minimum value and a maximum value.
13. Gas hotplate according to one of claims 1 to 12, characterised in that the gas supply unit (14) is designed such that a low-power range of the gas burner (1) is provided, in which the gas flow to the inner burner (4) is timed and the gas flow to the outer burner (2) is interrupted.
14. Gas hotplate according to one of claims 1 to 13, characterised in that to adjust the burner power within the low-power range (20) the clock ratio between on time and off time of the inner burner (4) is variable.
15. Gas hotplate according to one of claims 1 to 14, characterised in that within the low-power range (20) the gas flow to the inner burner (4) is set to the minimum value.

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