Method of operating a dual circuit gas burner, control unit, dual circuit gas burner and gas stove

Abstract

A method of operating a dual circuit gas burner including an inner burner ring and an outer burner ring surrounding the inner burner ring; the method including: opening a gas flow to the outer burner ring while maintaining a gas flow to the inner burner ring closed during a predetermined period of time.

Claims

1.-12. (canceled)

13. A method of operating a dual circuit gas burner, the method comprising opening a gas flow to an outer burner ring of the dual circuit gas burner while maintaining a gas flow to an inner burner ring of the dual circuit gas burner closed during a predetermined period of time.

14. The method according to claim 13, further comprising opening a gas flow to the inner burner ring at an inner burner opening time which is the predetermined period of time later than an outer burner opening time at which the gas flow to the outer burner ring is opened.

15. The method according to claim 14, wherein at the inner burner opening time, the outer burner ring is at a maximum opening state or at a predetermined intermediate opening state.

16. The method according to claim 13, further comprising varying the gas flow to the outer burner ring during the predetermined period of time.

17. The method according to claim 16, wherein the gas flow to the outer burner ring during the predetermined period of time is varied by: increasing the gas flow to the outer burner ring during a first portion of the predetermined period of time; and decreasing the gas flow to the outer burner ring during a second portion of the predetermined period of time which is subsequent to the first portion.

18. A control unit for adjusting a gas flow to a dual circuit gas burner, the control unit comprising a gas valve unit, said gas valve unit comprising: an adjustable outer burner outlet designed to adjustably provide an outer burner ring of the dual circuit gas burner with gas; and an adjustable inner burner outlet designed to adjustably provide an inner burner ring of the dual circuit gas burner with gas; wherein the gas valve unit is designed to open the adjustable outer burner outlet to provide the outer burner ring with a gas flow while maintaining the adjustable inner burner outlet closed during a predetermined period of time.

19. The control unit according to claim 18, designed to operate according to a method as set forth in claim 13.

20. The control unit according to claim 18, further comprising a control knob which is rotatable by a user, wherein the adjustable outer burner outlet and the adjustable inner burner outlet are designed to adjust their gas outlets to the outer and inner burner rings as a function of a position of the control knob.

21. The control unit according to claim 20, wherein the gas valve unit is configured to vary a total gas flow to the inner burner ring and the outer burner ring smoothly upon rotation of the control knob.

22. The control unit according to claim 20, wherein the predetermined period of time is defined by a duration at which the control knob is maintained in a position corresponding to opening the adjustable outer burner outlet while maintaining the adjustable inner burner outlet closed.

23. A dual circuit gas burner for a gas stove, the dual circuit gas burner comprising: a control unit comprising a gas valve unit, said gas valve unit comprising an adjustable outer burner outlet and an adjustable inner burner outlet; an inner burner ring connected to the adjustable inner burner outlet of the gas valve unit and designed to receive gas in accordance with an opening state of the adjustable inner burner outlet; and an outer burner ring connected to the adjustable outer burner outlet and designed to receive gas in accordance with an opening state of the adjustable inner burner outlet, wherein the gas valve unit is designed to open the adjustable outer burner outlet to provide the outer burner ring with a gas flow while maintaining the adjustable inner burner outlet closed during a predetermined period of time.

24. The dual circuit gas burner according to claim 23, wherein the control unit comprises a control knob which is rotatable by a user, wherein the adjustable outer burner outlet and the adjustable inner burner outlet are designed to adjust their gas outlets to the outer and inner burner rings as a function of a position of the control knob.

25. The dual circuit gas burner according to claim 24, wherein the gas valve unit is configured to vary a total gas flow to the inner burner ring and the outer burner ring smoothly upon rotation of the control knob.

26. The dual circuit gas burner according to claim 24, wherein the predetermined period of time is defined by a duration at which the control knob is maintained in a position corresponding to opening the adjustable outer burner outlet while maintaining the adjustable inner burner outlet closed.

27. A gas stove, comprising: a dual circuit gas burner comprising a control unit, said control unit comprising a gas valve unit which comprises an adjustable outer burner outlet and an adjustable inner burner outlet, an inner burner ring connected to the adjustable inner burner outlet of the gas valve unit and designed to receive gas in accordance with an opening state of the adjustable inner burner outlet, and an outer burner ring connected to the adjustable outer burner outlet and designed to receive gas in accordance with an opening state of the adjustable inner burner outlet, wherein the gas valve unit is designed to open the adjustable outer burner outlet to provide the outer burner ring with a gas flow while maintaining the adjustable inner burner outlet closed during a predetermined period of time; and a plate having an upper surface on which the dual circuit gas burner is mounted.

28. The gas stove according to claim 27, wherein the control unit comprises a control knob which is rotatable by a user, wherein the adjustable outer burner outlet and the adjustable inner burner outlet are designed to adjust their gas outlets to the outer and inner burner rings as a function of a position of the control knob.

29. The gas stove according to claim 28, wherein the gas valve unit is configured to vary a total gas flow to the inner burner ring and the outer burner ring smoothly upon rotation of the control knob.

30. The gas stove according to claim 28, wherein the predetermined period of time is defined by a duration at which the control knob is maintained in a position corresponding to opening the adjustable outer burner outlet while maintaining the adjustable inner burner outlet closed.

Description

[0052] Further embodiments, features and advantages of the present invention will become apparent from the subsequent description and dependent claims, taken in conjunction with the accompanying drawings, in which:

[0053] FIG. 1 shows a gas stove according to an embodiment;

[0054] FIG. 2 shows a dual circuit gas burner according to an embodiment;

[0055] FIG. 3 shows a control unit according to an embodiment;

[0056] FIG. 4 shows an operation of a gas burner known from the prior art;

[0057] FIG. 5 shows a method of operating a dual circuit gas burner according to an embodiment;

[0058] FIG. 6 shows an operation of a gas burner according to a first example;

[0059] FIG. 7 shows an operation of a gas burner according to a second example; and

[0060] FIG. 8 shows an operation of a gas burner according to a third example.

[0061] In the Figures, like reference numerals designate like or functionally equivalent elements, unless otherwise indicated.

[0062] FIG. 1 shows a gas stove 100 viewed from above. The gas stove 100 includes a plate 101 with an upper surface 102. Four dual circuit gas burners 1 are arranged on the upper surface 102. The gas burners 1 are different in size but their operation is identical. The upper surface 102 further has four control knobs 103 arranged thereon, which can be rotated by a user to adjust the gas flow to the respective gas burners 1, as will be explained further below.

[0063] FIG. 2 shows an example of a dual circuit gas burner 1 for the gas stove 100 of FIG. 1. The gas burner 1 shown in FIG. 2 includes an outer burner ring 2 having a circular shape. Outer gas outlet openings 3 are arranged along an outer perimeter of the outer burner ring 2 such as to emit flames radially outwards. The gas burner 1 of FIG. 2 further includes an inner burner ring 4 having a circular shape. Inner gas outlet openings 5 are arranged along an outer perimeter of the inner burner ring 4 such as to emit flames radially outwards.

[0064] FIG. 3 shows a control unit 20 for adjusting a gas flow to the gas burner 1. The control unit 20 includes a gas valve unit 14. The gas valve unit 14 comprises a main gas line 6 providing gas or a gas mixture to the gas burner 1. A main gas valve 7 is arranged in the main gas line 6. A branch line 8 to the outer burner ring 2 and a branch line 9 to the inner burner ring 4 branch off from the main gas line 6 downstream of the main gas valve 7. In each of the branch lines 8, 9 there is an on/off valve 10, which can be designed as a solenoid valve, for example, as well as 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 the external burner 2 or to the internal burner 4 can be adjusted steplessly or in several stages.

[0065] The control valves 11 can, for example, each be driven by a stepper 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 ring 2 or to the inner burner ring 4 is completely interrupted and reopened at predetermined times. This can be done, for example, by opening and closing the on/off valve 10 or by opening and closing the control valve 11 in the corresponding branch line 8, 9.

[0066] Accordingly, the valves 10, 11 of the branch line 8 to the outer burner ring 2 allow to adjustably provide the outer burner ring 2 with gas. This gas is provided through an adjustable outer burner outlet 16 located on the branch line 8 downstream of the valve 11. Further, the valves 10, 11 of the branch line 9 to the inner burner ring 4 allow to adjustably provide the inner burner ring 4 with gas. This gas is provided through an adjustable inner burner outlet 15 located on the branch line 9 downstream of the valve 11.

[0067] The main gas valve 7 as well as the on/off valves 10 and the control valves 11 are controlled by means of a preferably electronic control unit 12, which is connected to the valves 7, 10, 11 via control lines 13. The electronic control unit 12 can be coupled to the control knob 103 and send a control signal through the control lines 13 as a function of the position of the control knob 103 set by the user, thereby selecting the gas flow to the outer and inner burner 2, 4.

[0068] FIG. 4 shows an example of an operation of a gas burner 1 in the prior art. FIG. 4 comprises three parts: (a), (b) and (c), wherein part (a) represents the power (in kW) of the outer burner ring 2, part (b) represents the power (in kW) of the inner burner ring 4, and part (c) represents the total power (in kW) of the gas burner 1, namely an addition of the power of both burner rings 2, 4. The power output by the burner 1 and the burner rings 2, 4 is proportional to the gas flow provided to the burner 1 and burner rings 2, 4.

[0069] The horizontal axis of FIG. 4 shows an evolution of the operation of the gas burner 1 as the control knob 103 is rotated. On the leftmost point of FIG. 4, the gas burner 1 is OFF, which indicates that no gas is reaching the inner or outer burner 2, 4. Upon rotating the control knob 103, the gas burner 1 is turned on. Upon turning on the gas burner 1, the inner burner ring 4 is provided with gas and continuously maintained with gas while the outer burner ring 2 is provided with gas. In other words, a gas flow to the inner burner ring 4 is open at all times while the gas flow to the outer burner ring 2 is open. When the gas flow to the outer burner ring 2 is open, the gas flow to the inner burner ring 4 is at its maximum Max (b).

[0070] In zone Z1 of FIG. 4, through rotation of the control knob 103, the gas flow to the outer gas burner 2 is increased until the outer burner ring 2 reaches its maximum Max (a). The total power of the gas burner 1 is maximum Max (c) when the outer burner ring 2 reaches its maximum Max (a).

[0071] In zone Z2 of FIG. 4, rotating the control knob 103 further will decrease the gas flow to the outer burner ring 2 until the outer burner ring 2 is turned off. The gas burner 1 is then at its intermediate operation state Int. To decrease the power of the gas burner 1 even further, in zone Z3, the outer burner ring 2 is kept off, while the power to the inner burner ring 4 is reduced until the gas burner 1 reaches its minimum power Min.

[0072] In the operation of the gas burner 1 known from the prior art and shown in FIG. 4, the gas flow to the inner burner ring 4 is always open when the gas flow to the outer burner ring 2 is open. The inner burner ring 4 can however disturb the secondary air flow to the outer burner ring 2. As a result, there is a risk that the flame at the outer burner ring 2 is extinguished due to the lack of secondary air.

[0073] To overcome this problem, the gas burner 1 is advantageously operated according to the operation method shown in FIG. 5.

[0074] In detail, according to step S1 of FIG. 5, a gas flow to the outer burner ring 2 is opened while maintaining a gas flow to the inner burner ring 4 closed during a predetermined period of time. This is achieved by keeping the valves 10, 11 of the branch line 9 to the inner burner ring 4 closed while opening the valves 10, 11 of the branch line 8 to the outer burner ring 2. Advantageously, it is prevented that the inner burner ring 4 interferes with the secondary air to the outer burner ring 2.

[0075] Optionally, in a step S2 shown in FIG. 6, the gas flow to the inner burner ring 4 is opened after the predetermined period of time has elapsed since the gas flow to the outer gas burner ring 2 was opened. This is achieved by opening the valves 10, 11 of the branch line 9 to the inner burner ring 4 while keeping the valves 10, 11 of the branch line 8 to the outer burner ring 2 open.

[0076] The control of the operation of the valves 10, 11 is performed by the control unit 12 in response to a position of the control knob 103.

[0077] FIG. 6 shows an example of an operation and power output of the gas burner 1. The structure of FIG. 6 is similar to that of FIG. 4, and in particular also includes three parts (a), (b) and (c) corresponding to the outer burner ring 2, the inner burner ring 4 and the entire gas burner 1. FIG. 6 further shows a time axis showing labels at which particular events occur, as will be detailed below.

[0078] As can be seen in FIG. 6, when the gas burner 1 is turned on at an outer burner opening time t.sub.1, only the gas flow to the outer gas ring 2 is opened, while the gas flow to the inner gas ring 4 remains closed. For a predetermined period of time T after the outer burner opening time t.sub.1, only the gas flow to the outer gas ring 2 is opened while the gas flow to the inner gas ring 4 remains closed. This corresponds to the state achieved through step S1 of FIG. 5 described above. During this predetermined period of time T, the gas flow to the outer burner ring 2 is varied: during a first portion T1, it is increased until it reaches its maximum Max (a), and during a second portion T2, it is decreased again.

[0079] At a time t.sub.2, the predetermined period of time T has elapsed, which corresponds to a user rotating the control knob 103 beyond a predetermined position. The time t.sub.2 marks the opening of the gas flow to the inner burner ring 4 and can be designated as the inner burner opening time t.sub.2. As a result, at and shortly after the inner burner opening time t.sub.2, the total power to the gas burner 1 increases again. Upon rotating the control knob 103 further, the gas flow to the outer burner ring 2 is decreased further while the gas flow to the inner burner ring 4 remains constant. This results in a decreasing power of the gas burner 1. The gas flow to the outer burner ring 2 decreases until it is entirely off (Int state in FIG. 6). Then, upon rotating the control knob 103 further, the gas flow to the inner burner ring 4 is reduced further until it reaches its minimum Min.

[0080] The operation of the gas burner 1 shown in FIG. 6 is a mere example and different operations are possible, as shown in FIGS. 7 and 8, for example.

[0081] In the example of FIG. 7, the inner burner ring 4 is opened at the time at which the gas flow to the outer burner ring 2 is maximum Max (a). As a result, the total maximum Max (c) output of the gas burner 1 is higher than in the example of FIG. 6, because the addition of the power of the inner burner ring 4 to power of the outer burner ring 2 occurs before the power of the outer burner ring 2 is decreased again. This results in a smoother operation curve as compared to the curve of FIG. 6.

[0082] The example of FIG. 8 is similar to the example of FIG. 6, wherein the power through the outer burner ring 2 is set such as to be the same as the power of opening the inner burner ring 4. This results in a smoother operation curve as compared to the curve of FIG. 6.

[0083] Although the present invention has been described in accordance with preferred embodiments, it is obvious for the person skilled in the art that modifications are possible in all embodiments. For example, the control unit 20 can be different from the control unit shown in FIG. 3. In particular, the control unit 20 may include only the valves 11 but not the valves 10.

REFERENCE NUMERALS

[0084] 1 dual circuit gas burner [0085] 2 outer burner ring [0086] 3 outer gas outlet opening [0087] 4 inner burner ring [0088] 5 inner gas outlet opening [0089] 6 main gas line [0090] 7 main gas valve [0091] 8, 9 branch line [0092] 10 on/off valve [0093] 11 control valve [0094] 12 control unit [0095] 13 control line [0096] 14 gas valve unit [0097] 15 adjustable inner burner outlet [0098] 16 adjustable outer burner outlet [0099] 20 control unit [0100] 100 gas stove [0101] 101 plate [0102] 102 upper surface [0103] 103 control knob [0104] t.sub.1 outer burner opening time [0105] t.sub.2 inner burner opening time [0106] T predetermined period of time [0107] T1 first portion [0108] T2 second portion [0109] S1, S2 method steps