WO2008031645A1

WO2008031645A1 - A safety device for a gas-cooking appliance

Info

Publication number: WO2008031645A1
Application number: PCT/EP2007/056445
Authority: WO
Inventors: Alessandro Coppola; Adriano Fardin
Original assignee: Alessandro Coppola; Adriano Fardin
Priority date: 2006-09-14
Filing date: 2007-06-27
Publication date: 2008-03-20
Also published as: EP2069689A1

Abstract

The present invention relates to a safety device (100) for a gas-cooking appliance (101) comprising sensor means (5) for detecting the presence of at least a piece of cookware on at least burner (3) of said cooking appliance. The gas cooking appliance comprises also a control unit (70) that receives from said sensor means at least a detection signal (201) that is indicative of the presence of said piece of cookware. The control unit controls the operation of gas regulating means (4) for enabling/disabling the gas flow in said gas-cooking appliance.

Description

A SAFETY DEVICE FOR A GAS-COOKING APPLIANCE

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DESCRIPTION

The present invention relates to gas-cooking appliances. More particularly, the present invention relates to an improved safety device for gas-cooking appliances. Domestic accidents occur quite often in everyday life. As is reported by the Italian Central Statistics Office, in Italy there are almost four million accidents per year, due to minor or major risks concerning the domestic environment.

A large percentage of these accidents relates to the use of gas-cooking appliances. More particularly, many of these accidents derive from forgetting to turn off the gas burners on gas- cooking surfaces.

Given these facts, manufacturers of gas-cooking appliances have developed several kinds of safety devices for gas-cooking appliances.

A known safety device comprises a series of thermocouples, each of which is operatively coupled to a burner of the gas-cooking appliance. The burner flame heats the probe of the thermocouple, which generates a signal enabling the opening of a valve that controls the gas flow. In the case the flame were to be extinguished, the probe (no longer heated), immediately closes said valve, thereby blocking the gas flow.

Another known safety device works in combination with a safety valve of the gas-cooking appliance. If the burner flame goes out, the valve immediately interrupts the gas flow. The presence of a control device, including a microchip, enables to newly light on the burner in an automatic way, without any need to press any knob again.

Other known safety devices comprise a timer, which can be set at a desired cooking time. As the set cooking time elapses, the gas burner is automatically turned off.

Other known safety devices comprise a pushbutton. In case of emergency, said pushbutton enables all the gas burners to be turned off simultaneously or enables to block any exit of gas from the burners, thereby blocking the operation of the gas-cooking appliance. Finally, other known safety devices provide for a warning light, which remains lit up on the cooking surface until the burner rings and hubs cool down, once the gas has been turned off. Safety devices of the known type have drawbacks.

Very often, relatively poor performances in terms of safety are offered, since known safety devices often need the intervention of the user to block the gas flow. Further, the operation mode of many traditional devices does not fully consider the user's needs during the cooking activity. Thus, the presence of the safety device may be quite uncomfortable for the user, during the normal cooking activity, and determine a remarkable limitation of the flexibility of use of the gas cooking appliance, on which the safety device is installed.

Other disadvantages reside in that the traditional safety devices are often relatively cumbersome, relatively expensive to manufacture and are difficulty installable on gas-cooking appliances that already in used.

Thus, it is an aim of the present invention to provide a safety device for gas-cooking appliances, which allows the overcoming of the drawbacks described above.

Within this aim, it is an aim of the present invention to provide a safety device, which is very reliable and ensures high performances in terms of safety.

Another object of the present invention is to provide a safety device, which does not reduce the comfort of the user during the normal cooking activity.

Another object of the present invention is to provide a safety device, which has a relatively small size and which is easy to install, even on cooking appliances already in use.

Another object of the present invention is to provide a safety device, which is quite easy to manufacture at industrial level, at competitive costs.

Therefore, the present invention provides a safety device for gas-cooking appliances according to the following claim 1.

The safety device, according to the present invention, basically provides an automatic control of the burners of the gas cooking appliance without any initial programming by the user. In particular, the gas flow to the burners of the gas-cooking appliance is controlled, on the base of signals that are indicative of the presence of pieces of cookware on the burners.

Preferably, the safety device, according to the present invention, ensures a gas supply to a burner, only if a piece of cookware is positioned on the burner itself.

Preferably, when a piece of cookware is removed from the burner, the safety device, according to the present invention, provides for the burner to remain lit for a predefined first time interval before the gas supply is turned off.

Preferably, the safety device, according to the present invention, determines the blocking of the gas supply when a piece of cookware is left on the burner for a period longer than a predefined second time interval.

The safety device, according to the present invention, can be easily applied to all commercially available gas-cooking appliances, even when they are already in use. To this aim, a simple installation procedure can be adopted.

As it will be better illustrated in the following, the safety device, according to the present invention, has a simple structure, which can be easily manufactured at industrial level.

Further features and advantages of the safety device, according to the present invention, will become apparent from the following description of preferred embodiments, taken in conjunction with the drawings, in which:

Fig. 1 represents a schematic cross-sectional view of a portion of a gas-cooking appliance comprising the safety device, according to the present invention; and

Fig. 2 represents a schematic cross-sectional view of a gas-cooking appliance comprising the safety device, according to the present invention; and

Fig. 3 represents a schematic view of the structure of the safety device, according to the present invention.

Referring now to the cited figures, the safety device 100, according to the present invention comprises sensor means 5 for detecting the presence of at least a piece of cookware 102 on at least a burner 3 of a gas cooking appliance 101.

The sensor means 5 comprise one or more sensors, each of which is associated to a single burner 3 of the cooking appliance 101. Alternatively, a plurality of sensors 5 can be associated to each burner 3. The sensors 5 are preferably positioned in proximity of the burner 3 and they can detect the presence of the piece of cookware 102, without being in contact with it.

Moreover, each sensor 5 works independently from the remaining ones that are present on the cooking surface.

Preferably, the sensors 5 are optical-fiber sensors of the glass type with direct-reflection detection. These sensors make it possible to detect any solid (even a transparent one) up to the maximum distance of 200 mm and they are not subjected to interference phenomena due to the presence of the flame, and to resist temperatures of between -40⁰C and 290⁰C, as well as splashes of oil and the like. The optical-fiber sensor 5 is operatively connected to at least an optical- fibre amplifier 51, which may be provided with an adjustable flow-rate running from 0 to 300 mm. The optical- fibre amplifier 51 may be also be provided with a display (not shown), so as to visualize the detection signal 201 that is provided in output by the amplifier 51.

The safety device 100 comprises also a control unit 70, which receives from the sensor means

5 at least a detection signal 201 that is indicative of the presence of the piece of cookware 102.

On the base of the detection signal 201, the control unit 70 generates a control signal 202 for controlling the operation of gas regulating means 4, which enables/disables the gas flow 1 in the gas-cooking appliance 101.

Preferably, the control unit 70 is arranged, so as to generate a control signal 202A for enabling the gas flow 1 in the gas-cooking appliance 101.

In order to disable the gas flow 1, the control unit 70 stops generating the enabling control signal 202A or, in alternative, it may generate a disabling control signal 202B.

In any case, the control unit 70 is preferably arranged to enable the gas flow 1 , only when the piece of cookware 102 is positioned on the burner 3.

The control unit 70 is also arranged for providing certain delay functionalities for what concerning the control of the gas flow 1 in the gas-cooking appliance 102.

In particular, the control unit 70 disables the gas flow 1 after a predefined first time interval, which starts running when the piece of cookware 102 is removed from the burner 3.

Similarly, the control unit 70 disables the gas flow in the gas-cooking appliance 101, when the piece of cookware 102 remains on the burner 3 for a period longer than a predefined second time interval.

The first and second time intervals are preferably predefined on the base of the functionalities provided by the gas cooking appliance 101 and/or on the base of normal cooking times. These time intervals are set during the installation of the safety device 100. Preferably, the first time interval cannot be modified by the user, so as to increase the safety level of the safety device

100. Instead, the second time interval might be modified by the user, according to the needs of the cooking activity.

In its industrial realisation, the control unit 70 may comprise one or more electronic boards or, preferably, a microprocessor or a digital signal processor.

The gas regulating means 4 preferably comprise one or more solenoid gas valves, having a

230-Vac input voltage, at a frequency of 50/60 Hz. Each of said gas valves 4 is arranged, so as to control the gas flow 1 of a single burner 3. To this aim, each gas valve 4 is positioned, so as to intercept the gas-supply pipe 11 that connects each burner 3 with its regulating knob 2.

Since solenoid gas valves are used, the control signals 202 generated by the control unit 70 are advantageously current signals.

The enabling current signals 202A determine the energization of the solenoids (not shown) for the direct opening of the solenoid gas valves 4 and the consequent enabling of the gas flow.

The simple termination of the deliver of the energising current signals 202A or the deliver of opposite current signals 202B determine the de-energization of said solenoids, thereby disabling the gas flow. Power supply means 80 are preferably used for supplying electric power 81 to the safety device 100. In particular, a 220- Vac power supply having one or more 12/24-Vdc outputs may be advantageously adopted for feeding the various components of the safety device 100. Switching means 6, such as an electrical switch, are advantageously provided for controlling the supply of electric power to the gas-cooking appliance 101 and to the safety device 100. The operation of the safety device 100, according to the present invention, is simple and effective.

If the switch 6 is in the ON condition, a light beam of the optical-fibre sensor 5 detects the piece of cookware 102 and transmits a light signal to the optical- fibre amplifier 51. The latter sends the detection signal 201 to the control unit 70, which, in turn, generates a control signal 202A to determine the opening of the solenoid gas valve 4, enabling the supply of the gas 1. Otherwise, if the light beam of the optical- fibre sensor 5 does not detect any piece of cookware 102 (or the switch 6 is in the OFF condition), the control unit 70 does not receive any signal 201. Therefore, it does not generate any control signal 202A to determine the opening of the solenoid gas valve 4, which automatically remains or turns in its normal condition of turned off, preventing the supply of the gas 1.

This mode of operation is advantageous since it ensure maximum safety. Of course, alternative operation modes are possible.

For example, if the light beam of the optical-fibre sensor 5 does not detect any piece of cookware 102, the control unit 70 may receive in input a signal 201, which indicates that no piece of cookware is present. Therefore, a control signal 202B may be generated to keep or turn the solenoid gas valve 4 in its normal off condition, preventing the supply of the gas 1. As a further alternative, the operation mode of the safety device 100 might be also dual with respect to that one described, with the gas valves 4 normally open and the gas flow 1 enabled in normal operating conditions.

As briefly illustrated above, the control unit 70 provides timing functionalities for what concerning the turning the solenoid gas valve 4 to the off condition.

Timing of the solenoid gas valve 4 is necessary to guarantee that the burner 3 remains lit for a pre-set first time interval, when the piece of cookware 102 is shortly removed from the burner 3 (for example, to transfer the contents of the container). The first time interval described above may be expressed as a fraction of a minute and it is preferably not modifiable by the user. Should the cooking container 102 no longer be put back on the burner 3, when the first time interval elapses, the control unit 70 sends a closing signal 202 to the solenoid gas valve 4, with consequent turning-off of the gas 1.

Another reason for which timing of the solenoid gas valve 4 is preferable is to enable blocking of supply of the gas 1 in the case where the cooking container 102 is left on the burner for a time longer than the pre-set second interval. The second time interval described above may correspond to a maximum cooking time (e.g. expressed in hours) and it might preferably be modifiable by the user.

The safety device 101 can be easily installed. The installation may occur either during the manufacturing process of the gas cooking appliance or even when the gas-cooking appliance is already in use. The following simple procedure may be adopted.

A first step consists in interrupting the pipes 11 for supply of the gas 1 from the knobs 2 to the burners 3. For each supply pipe 11, a solenoid gas valve 4 is inserted, with a 230- Vac input voltage, a frequency of 50/60 Hz, and attachments suitable to match with the section of the supply pipes 11.

A second step consists in making a hole on the top part of the cooking surface of the gas cooking appliance 101, which is located in the proximity of each burner 3. Housed in each hole is one optical- fibre sensor 5.

A third step consists in making a hole on the front control panel (near the knobs) for housing an ON/OFF electrical switch 6 of a type that is lit-up when in the ON position for greater visibility.

A fourth and last step regards electrical and electronic wiring. For electrical operation of the invention, it is advantageous to use an electrical box 7 of average dimensions for housing the power supply 80, the control unit 70 and the fibre-optic amplifier 51.

It has been proven that the safety device 100, according to the invention, allow to achieve the intended aims and objectives.

The safety device 100 has an extremely simple structure, which allows it to be easily manufactured and installed.

The safety device 100 does not limit at all the comfort in using the cooking appliance 101, on which it is installed.

In fact, it works substantially in an automatic manner (once the switching means 6 are activated), without the need of further user's interventions.

In addition, its main functionalities take into consideration the most common needs of user during the normal cooking activity.

Finally, it has been proven how the safety device 100 ensures a high level of reliability, in any kind of cooking conditions.

Claims

1. A safety device (100) for a gas-cooking appliance (101), characterized in that it comprises: sensor means (5) for detecting the presence of at least a piece of cookware on at least burner (3) of said cooking appliance; a control unit (70), which receives from said sensor means at least a detection signal (201) that is indicative of the presence of said piece of cookware, said control unit controlling the operation of gas regulating means (4) for enabling/disabling the gas flow in said gas-cooking appliance.

2. A safety device, according to claim 1, characterized in that said control unit generates at least a control signal (202) for controlling the operation of said gas regulating means.

3. A safety device, according to one or more of the previous claims, characterized in that said sensor means detect the presence of said piece of cookware, without being in contact with said piece of cookware.

4. A safety device, according to one or more of the previous claims, characterized in that said sensor means are positioned in proximity of said burner.

5. A safety device, according to one or more of the previous claims, characterized in that said sensor means comprise one or more sensors, each of said sensors being associated to each burner of said cooking appliance.

6. A safety device, according to claim 5, characterized in that each of said sensors works independently from the other sensors.

7. A safety device, according to one or more of the claims from 5 to 6, characterized in that said sensor means comprise at least an optical- fibre sensor.

8. A safety device, according to claim 7, characterized in that said optical- fibre sensor is operatively connected to at least an optical- fibre amplifier (51).

9. A safety device, according to one or more of the previous claims, characterized in that said control unit generates at least a control signal (202A) for enabling the gas flow in said gas-cooking appliance, when said piece of cookware is positioned on said burner.

10. A safety device, according to claim 9, characterized in that said control unit disables the gas flow in said gas-cooking appliance after a predefined first time interval elapses, said first time interval running since when said piece of cookware is removed from said burner.

11. A safety device, according to one or more of the claims from 9 to 10, characterized in that said control unit disables the gas flow in said gas-cooking appliance, when said piece of cookware remains on said burner for a period of time longer than predefined second time interval.

12. A safety device, according to one or more of the previous claims, characterized in that said gas regulating means comprise one or more solenoid gas valves.

13. A safety device, according to claim 10, characterized in that each of said solenoid gas valves intercepts the gas-supply pipe that connects each burner of said gas-cooking appliance with its regulating knob.

14. A safety device, according to one or more of the previous claims, characterized in that it comprises switching means (6) for controlling the supply of electric power (81) to said gas-cooking appliance.

15. A safety device, according to one or more of the previous claims, characterized in that it comprises power supply means (80) for supplying electric power to said control unit and/or said sensor means.

16. A gas-cooking appliance characterized in that it comprises a safety device according to one or more of the previous claims.

17. A procedure for arranging a safety device, according to one or more of the previous claims, on a gas-cooking appliance, characterized in that it comprises at least the following steps: inserting said gas regulating means in the pipes for supplying the gas to the burners of said cooking appliance; making one or more holes in portions of the cooking surface of said gas cooking appliance, which are located in the proximity of said burners, and housing said sensor means in said holes; making a hole on the front control panel for housing said switching means; arranging an electrical box (7) for containing at least said power supply means and said control unit.

18. A gas cooking appliance characterized in that it comprises at least a solenoid gas valve to regulate the gas flow to at least a burner of said gas cooking appliance.