JPH08215039A - Cooking apparatus with glass-ceramic cooking surface - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve unstable condition at the time when it is started by a method wherein existence of flame is monitored through a flame monitoring device by means of a controller and when the flame is not detected, a glow ignition tool is continuously worked and the switch of the glow ignition tool is turned off after a specified time passes. SOLUTION: A glow ignition tool 5 is heated by the passage of electric current through an electronic controller 6 by operating a working nob 7 and after a solenoid valve 4 is opened, a breeze device 2 is ignited. Then, after a specified time has passed, a question signal is transmitted to a flame monitoring device 8 from the electronic controller 6 so as to detect existence of a gas flame by the breeze device 2. As the result, when existence of the flame is detected, the switch of the glow ignition tool 5 is turned off. On the other hand, when no existence of the flame is detected, the glow ignition tool 5 is continuously worked. In addition, the solenoid valve 4 is simultaneously closed to stop urgently a cooking tool with a glass ceramic cooking face 1.

Description

Detailed Description of the Invention

[0001]

The present invention relates to a glass-ceramic cooking surface, one or more gas radiant burners each having a gas supply device with a solenoid valve, an incandescent igniter, a flame monitoring device, and an incandescent igniter. A cookware with a glass-ceramic cooking surface having an on / off switch, as well as a control for actuating and monitoring the burner.

[0002]

2. Description of the Related Art Cooking utensils of the type mentioned above are known, for example, from German Patent Publication No. 40 03 799. In the configuration described here, the gas burner is ignited by an incandescent or glow igniter and the ionization section is monitored for the presence of a gas flame. As soon as a gas flame is detected, the incandescent igniter is switched off by the control device.

A monitoring device of this kind has the advantage that the incandescent igniter is switched off shortly after the ignition of the flame and thus eliminates its unnecessary heating. However,
Such a structure has the disadvantage that the gas flame does not always steadily burn at the start of combustion after ignition and after detection by the ionization section. Stable combustion characteristics are largely determined by the gas mixture used. If the combustion characteristics of the gas flame are not stable and the gas flame is extinguished again, the device must detect the extinction of the flame and start a new start procedure. For safety reasons, if the number of re-ignition attempts within a given period is very low, the performance of the ignition mechanism components cannot be expected to be stable and will be temporarily interrupted.

[0004]

In order to eliminate this kind of difficulty, the object of the invention is to keep the instability at the start of the burner operating the incandescent igniter for an unnecessarily long time. It is to solve without any.

[0005]

In order to achieve this object of the invention, the features set forth in claim 1 are proposed.

The basic idea of the proposed method for achieving the object of the present invention is that, after a first predetermined time period has passed, statistically with respect to the flame of the gas to be checked for its presence by the flame detection device. It is taken into account that the burner can be expected to operate in a stable manner. If there is a flame, the incandescent igniter is switched off, and if there is no flame, the gas flame is checked again for a predetermined period of time corresponding to the specified safety time. If the gas flame is still absent, it is assumed to be in failure and the cookware is switched to a so-called emergency stop routine due to failure, shutting down all burners, not just the failed burner.

The proposed structure severely limits the number of restart attempts performed by the controller, which reduces the delay time it causes. As a result, the cookware is stable in start-up when operating with gas mixtures of varying quality.

According to the present invention, there is provided a control device which outputs a period of 5 seconds as the first predetermined time and outputs a period of 10 seconds as the second predetermined time. It will be appreciated that according to the invention, these periods can be varied.

According to the development of the invention, the control unit is preferably realized by a microprocessor, but instead of this, an ASIC. A
n-ionized compartments can be used.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 shows a glass-ceramic cooking surface 1 under which a fleece device 2 is arranged. The gas is supplied via the gas conduit 3 and the solenoid valve 4. The incandescent or glow igniter 5 is controlled by an electronic control unit 6. The electronic control unit 6 is also connected to the solenoid valve 4. The electronic controller receives commands from a conventional actuation knob 7 located on the hob of the cooker. The ionization section 8 is also electrically connected to the electronic control unit 6, which serves the purpose of flame monitoring.

The operation mode of the device is as follows. That is, after energizing the knob 7, a current is supplied to the incandescent igniter 5 to heat it, the solenoid valve 4 is opened, and then the fleece device is ignited. After activating the incandescent igniter, a predetermined time elapses, in this case, after 5 seconds elapses, the control device 6 detects the presence or absence of the gas flame based on the state of the fleece device. An inquiry signal is sent to the detection device 8. When the flame monitoring device 8 detects a flame, the control device 6 switches off the incandescent igniter 5. On the other hand, when it is detected that there is no flame, the incandescent igniter continues to operate, and after a predetermined time has elapsed, in this case, after 5 seconds, the control device sends a new inquiry signal to the flame monitoring device. Send to 8. The incandescent igniter is switched off at this time. If a flame is detected, the solenoid valve 4 remains open, but if no flame is detected, the valve is closed and all burners of the cookware have an emergency stop due to a failure and the signal is It is output to a buzzer or a display (not shown).

First, the operating mode of a known cooking appliance control system, in which the incandescent igniter is switched off when a flame signal is detected, will be described with reference to FIGS. 2a, 2b and 2c.

FIG. 2a shows the operating states of the structural units of the cooking utensil along the time axis. If the operating voltage is present and the operating knob is activated, the cookware fan is switched on first and the incandescent igniter switch is switched on after the waiting time determined by the device has elapsed. Turn on, then after preheat time, turn on solenoid valve for gas flow. After a predetermined time, ignition of flame is started and a flame signal is detected. The flame signal is intermittent at first. In each case, the switch of the igniter is temporarily switched off and on again until the continuously generated flame signal indicates that the flame is steadily burning. The incandescent igniter is finally switched off.

FIG. 2b shows that when the already existing flame is extinguished for some reason, a signal indicating that the flame is extinguished is output by the flame monitoring device and at the same time the igniter is switched on. . Furthermore, it can be seen from this figure that after the flame burns in a steady state, the igniter is finally switched off after a number of interruptions and the signal indicating that the flame has disappeared disappears. If the fault condition is of very short duration, the ignition procedure will successfully ignite it within a safe period, so that the solenoid valve will not be switched off and the valve will remain open.

Finally, FIG. 2c shows the case where ignition was not successful after a short fault condition. Similar to the state shown in FIG. 2b, after the flame is extinguished, a signal indicating that the flame is extinguished is generated, and at the same time, it can be seen that power is supplied to the incandescent igniter. After the safety period ts has elapsed, the solenoid valve is switched off and an emergency stop signal due to a failure is issued.

Next, the operation mode of the present invention will be described with reference to FIGS. 3 (a), 3 (b) and 3 (c).

After activating the button 7, the fan is first switched on, and after the waiting time has elapsed, the incandescent igniter 7 is switched on and then the solenoid valve is opened. After the time t1 has elapsed, the control device 6 is inspected to see if the flame monitoring device 8 has detected a gas flame. In the case of the present invention, if no flame is detected, at the end of time ts,
That is, power is continuously supplied to the incandescent igniter until the end of the safety period. In the meantime, the flame monitoring device 8 detects the flame signal,
At that time, the incandescent igniter 5 is switched off.

Reference is now made to FIG. 3b, which is similar to FIG. 2b, in a state of failure for a short time. It can be seen that after the flame has extinguished at time ta, and after a short time has passed, a signal indicating that the flame has extinguished is issued and at the same time the igniter is switched on. At time t1, after 5 seconds in this case, the fleece device is inspected to see if a flame is present. If the flame monitoring device 8 detects such a flame and no longer outputs a signal indicating that the flame is extinguished, the incandescent igniter is switched off at the end of the safety time ts. In this case, the solenoid valve remains open for the entire period. At time t1, the control device 6 newly inspects the flame monitoring device 8. If there is no signal that the flame is extinguished, then it is concluded that there is proper combustion flame and operation is working properly. At this time, the igniter is no longer operating.

Next, with reference to FIG. 3c, a fault condition similar to that of FIG. 2c in which the situation is not improved will be described. After the flame is extinguished, a signal indicating that the flame is extinguished is detected after a short period of time ta, and it can be seen that the incandescent igniter 5 is supplied with power. At time t1, the fleece device is inspected to see if there is a flame.
If there is no flame and there is a signal that the flame is extinguished, continue to power the igniter. After the safety period ts, the control device 6 again checks the flame monitoring device 8. There is a signal that the flame is extinguished as a sign that the flame is not present. The igniter is then switched off, the solenoid valve is closed, and the system is switched to a failure emergency stop routine. This routine outputs a signal to either the optical or acoustic display as an indication that the user is beginning a new rewind of the entire switching procedure, including button activation.

By comparing FIGS. 3a and 3b with FIGS. 2a and 2b, the device according to the invention ignites the igniter multiple times until a stable flame regime or pattern is obtained at the gas burner. It will be appreciated that rather than turning off or turning on the igniter, it does not "blink". Thus, the advantages of the invention described above are obtained.

[Brief description of drawings]

FIG. 1 is a schematic view of a cooking utensil including a control device.

FIG. 2 is a graph showing various ignition procedures for known cookware.

FIG. 3 is a graph showing various ignition procedures for a cookware according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Glass-ceramic cooking surface 2 Fleece device 3 Gas conduit 4 Solenoid valve 5 Glow igniter 6 Electronic control device 7 Operating knob 8 Flame monitoring device

Front page continuation (72) Inventors Christoph, Paul, Kalmar Rückelsdorf, Germany, Hohe, Linde, 4 (72) Inventors Gerhard, Becke Volkheim, Tannenwake, Germany, 4

Claims (5)

[Claims] 1. A glass-ceramic cooking surface, one or more gas radiant burners each having a gas supply with an electromagnetic valve, an incandescent igniter, a flame monitoring device, and an intermittent switch for the incandescent igniter, and a burner. In a cookware having a control device for operating and monitoring, the control device (6) turns on the gas after a predetermined time has elapsed after igniting the incandescent igniter (5) and switching on the solenoid valve (4). Ask the flame monitoring device (8) about the flame of, and if the flame is present, switch off the incandescent igniter, and if the flame is not present, after the scheduled time (safety time) has elapsed, reapply the flame monitoring device. Ask and switch off the incandescent igniter if a gas flame is present, and if no gas flame is present, perform an emergency stop due to the failure of the burner in question, glass Ceramic cooking surface with cooking utensils. 2. When a signal is received from the flame monitoring device (8) because the gas flame is extinguished, the control device (6) is
Cooking with glass-ceramic cooking surface according to claim 1, characterized in that at the start of ignition of the incandescent igniter (5), a new trial is carried out without switching off the solenoid valve (4) for the time being. Equipment. 3. The control device (6) generates a period of 5 seconds as the first predetermined time and a period of 10 seconds as the second predetermined time. Utensils with glass ceramic cooking surface. 4. Cookware with glass-ceramic cooking surface according to claim 1, characterized in that the control device (6) is in the form of a microprocessor. 5. Cookware with a glass-ceramic cooking surface according to claim 1, characterized in that an ionization section is provided as the flame monitoring device (8).