WO2013041454A1

WO2013041454A1 - Gas cooking appliance and method associated with said gas cooking appliance

Info

Publication number: WO2013041454A1
Application number: PCT/EP2012/068045
Authority: WO
Inventors: Jesús Ignacio ERRASTI BADIOLA; Amaia Salbide Mutiloa
Original assignee: Coprecitec SL
Current assignee: Coprecitec SL
Priority date: 2011-09-20
Filing date: 2012-09-14
Publication date: 2013-03-28
Anticipated expiration: 2014-03-20
Also published as: ES2399893A2; ES2399893R1; ES2399893B1; EP2758715B1; EP2758715A1; ES2571378T3

Abstract

Gas cooking appliance comprising a plurality of burners, each burner being associated to at least one actuator and a thermocouple (4). The actuator opens or closes the corresponding burner when a user acts on said actuator. The thermocouple (4) generates an electrical signal when it detects a flame in the corresponding burner. The cooking appliance also comprises at least one main valve that comprises a safety system that comprises a magnetic unit (5). Said magnetic unit is controlled according to the signals of the thermocouples (4), it being supplied directly and sequentially by the thermocouples (4) whose burners has been opened by acting the corresponding actuator.

Description

D E S C R I P T I O N

"Gas cooking appliance and method associated with said gas cooking appliance"

TECHNICAL FIELD This invention relates to gas cooking appliances, and in particular to gas cooking appliances that comprise a plurality of burners with a associated thermocouple.

PRIOR ART

Gas cooking appliances that comprise safety valves supplied by thermocouples for their use in gas burners are known. The thermocouple keeps the safety valve open for as long as there is a flame. In the event that the flame goes out, the safety valve closes, thereby cutting off the supply of gas. The safety unit formed by the safety valve and the thermocouple creates an intrinsically safe device, as any type of fault in said safety unit causes the safety valve to close, cutting off the gas supply as a result.

Gas appliances that comprise a plurality of burners with a thermocouple and a associated regulation valve, and which also comprise a main valve that requires an electrical signal to keep said valve in the open position are also known.

ES2336402 A1 thus discloses a gas cooking appliance that comprises four burners, each one of which is connected to a thermocouple in order to detect the presence of a flame, as well as an actuator and a regulation valve. Said appliance also comprises a main valve suitable for blocking the supply of gas to the various regulation valves and which is supplied in order to keep it in its open position by an electrical signal generated in a control unit. BRIEF DISCLOSURE OF THE INVENTION

It is the object of this invention to provide a gas cooking appliance and a method associated with said gas cooking appliance, as described in the claims.

The gas cooking appliance of the invention comprises a plurality of burners where each burner is associated to at least one actuator and a thermocouple. The actuator opens or closes the corresponding burner when a user acts on said actuator. The thermocouple generates an electrical signal when it detects a flame in the corresponding burner.

The cooking appliance also comprises at least one main valve that comprises a safety system that comprises a magnetic unit. Said magnetic unit is controlled according to the signals of the thermocouples, where it is supplied directly and sequentially by the thermocouples whose burners have been opened by acting on the corresponding actuator.

Thanks to the gas cooking appliance of the invention a cooking appliance with an economical safety system is achieved due to the fact that the cooking appliance is able to manage the electrical signals of the different thermocouples in order to supply a single magnetic unit. In addition, the cost of the regulation valves of each burner is also reduced significantly, as it is not necessary for said valves to comprise a magnetic unit in order to comply with the corresponding safety regulation. Similarly, the maintenance of said valves is also made easier due to the fact that as they are simpler valves, the risk of them becoming faulty is also reduced.

These and other advantages and characteristics of the invention will be made evident in the light of the drawings and the detailed description thereof. DESCRIPTION OF THE DRAWINGS

Figure 1 shows, partially, perspective view of a gas cooking appliance.

Figure 2 schematically shows an embodiment of the invention that may be implemented in the cooking appliance of Figure 1.

DETAILED DISCLOSURE OF THE INVENTION

The gas cooking appliance of the invention comprises a plurality of burners 1 and a regulation valve (not shown in the figures) associated to each burner 1 and suitable for opening, closing and/or adjusting the gas flow of said burner 1 . The cooking appliance 100 also comprises a main valve (not shown in the figures) where the gas flow that passes through each regulation valve passes through the main valve first of all. As a result, if the main valve is closed, no gas passes through to the regulation valves and, therefore, to the burners 1. Said main valve comprises a safety system that comprises a magnetic unit 5.

Thanks to the gas cooking appliance 100 and the method of the invention, the safety regulations relating to gas cooking appliances are met in a reliable and economical manner, as the apparatus operates with a single magnetic unit, considerably reducing the cost of the appliance. The regulation valves are also simpler, as they do not comprise the magnetic unit, thereby reducing the risk of them becoming faulty, which also reduces the maintenance of the gas cooking appliance.

Figure 1 shows an example of a gas cooking appliance that comprises four burners 1 . The cooking appliance also comprises an actuator 2 and a thermocouple 4 (shown schematically in Figure 2) associated to each burner 1 . The actuator 2 opens or closes the corresponding regulation valve, which in turn opens or closes the corresponding burner 1 when a user acts on said actuator 2. The thermocouple 4 generates an electrical signal when it detects a flame in the burner 1 . The magnetic unit 5 of the invention comprises a first coil 10, which is supplied by said electrical signal, in such a way that the magnetic unit 5 is supplied directly and sequentially by the thermocouples 4 whose burners 1 have been opened by acting on the corresponding actuator 2. The magnetic unit 5 also comprises a second coil 11 for detecting the state (open/closed) of the main valve.

In order to open one of the burners 1 the user must act on the corresponding actuator 2, which, as stated above, opens the regulation valve and, therefore, the burner 1. However, in order for gas to reach the regulation valve the main valve must be opened first of all, and to achieve this the gas cooking appliance 100 of the invention comprises, in this embodiment, pulsing means (not shown in the figures), which open said main valve manually. When the actuator 2 is acted on, ignition means 9 are also activated and light the corresponding burner 1 thanks to a spark plug, not shown in the figures, disposed close to the burner 1. The user must keep said pulsing means actuated for a sufficient period of time so that the electrical signal generated in the corresponding thermocouple 4 may supply by itself the magnetic unit 5. In a preferred embodiment of the invention, the cooking apparatus 100 comprises display means, not shown in the figures, which notify the user, for example, that they can stop acting on the pulsing means.

When one burner 1 has been opened, in order to open another burner 1 , its gas flow must be opened by opening the corresponding regulation valve, and in order to achieve this, the corresponding actuator 2 must be acted on. When said actuator 2 is acted on, the ignition means 9 are also activated and generate the necessary sparks in the spark plugs in order to light the burners 1. In this case, as there is already one burner 1 open, the main valve is already open and it is not necessary to act on the pulsing means.

To switch off the gas cooking appliance 100 of the invention all the regulation valves that are open must be closed, the corresponding actuator 2 being acted on for this purpose. As a result, the thermocouples 4 that were supplying the first coil 10 of the magnetic unit 5 stop supplying said magnetic unit 5 and the main valve is closed automatically. In this embodiment, it is not necessary to incorporate specific means to force the closure of the main valve, although said alternative is not ruled out as it may, in an emergency, be especially advantageous to obtain a single means that switches off the entire cooking appliance 100. By incorporating said specific means, unnecessary risks may be avoided, such as ignition another burner instead of putting out the one that had been intended to be put out, etc. These types of errors are usually very common in emergency situations (e.g., the spilling of burning oil on the hob of the cooking apparatus, etc), due to the nerves of the moment. Said means would also remove the need to spend time on selecting the actuator 2 of the required burner 1 , which in the event of an emergency could be dangerously high due to the nerves of the moment.

The gas cooking appliance 100 of the invention also comprises an actuation switch 3, shown schematically in figure 2, associated to each burner 1 and which changes state when the user acts on the corresponding actuator 2. As a result, when the burner 1 has been opened by acting on the actuator 2, the corresponding actuation switch 3 changes the state and the cooking appliance 100 is able to differentiate if said burner 1 , which is associated to the actuator 2, is open or closed. To achieve this, the gas cooking appliance 100 comprises control means 7, shown schematically in figure 2, which detect the state of said actuation switches 3 and act on supply switches 6 that are associated to each thermocouple 4. Each supply switch 6 opens or closes the flow of current of the associated thermocouple 4, supplying the first coil 10 of the magnetic unit 5 when the flow of current is allowed. As a result, when the control means 7 detect, through the actuation switches 3, that one or more burners 1 are open, they act on the corresponding supply switches 6, permuting them sequentially with the result that the first coil 10 of the magnetic unit 5 is reached only by the electrical signal of a single thermocouple 4. The permuting interval of said supply switches 6 is the minimum that guarantees the supply of the first coil 10 of the magnetic unit 5 and ensures the detection of faults, such as an unwanted shutdown of a burner 1.

The gas cooking appliance 100 of the invention also comprises a current sensor 8 associated to the magnetic unit 5. Said current sensor 8, shown graphically in figure 2, detects the current I that reaches the first coil 10 of the magnetic unit 5 through the different thermocouples 4. If, for example, in the preferred embodiment of the invention, two burners are lit, the value of the detected current I will vary sequentially, as the supply switches 6 are permuted, between the electrical signal of the thermocouple 4 of the first burner 1 and the electrical signal of the thermocouple 4 of the second burner 1. As a result, the current I detected by the current sensor 8 is unique and is which supplies the first coil 10 of the magnetic unit 5.

When said current I, detected by the current sensor 8, is slightly smaller than a predefined minimum current IMIN, or the slope of said current I is higher than a predetermined value, it means that the flame of one of the burners 1 has been shutdown in an unwanted manner. In this case, in the preferred embodiment of the invention, the ignition means 9 are activated for a preset TSAFETY time in order to reignit the burners 1 before the main valve is closed definitely. In a second embodiment, in said reignition phase, only the burners 1 whose flames have been shutdown in an unwanted manner are lit, in other words, those burners 1 whose regulation valve is open (or the actuator 2 actuated) and the corresponding thermocouple 4 does not generate an electrical signal.

If at the end of said preset TSAFETY time or if the value of the current I detected by the current sensor 8 falls to an IOFF value, close to zero, the main valve closes, cutting off the gas flow.

In a third embodiment, when an unwanted shutdown of a burner occurs, the main valve closes without activating any reignition phase.

In the preferred embodiment of the invention, when the main valve is closed while some actuators 2 being acted, the control means 7 do not act on the supply switches 6 until all the burners 1 have been closed, the actuators 2 being acted on for this purpose. In this case, the display means (not shown in the figures) warn the user of the fault so that they can rectify the problem.

Additionally, in the preferred embodiment, when the main valve is closed either because the user has closed all the open burners 1 voluntarily by acting on the corresponding actuators 2, or because the flame of an open burner 1 has been shutdown in an involuntary and unwanted manner, the control means 7 send a temporary electrical signal (Γ) that supplies the second coil 1 1 of the magnetic unit 5 in order to detect the state of the main valve. The control means 7 read the voltage between the terminals of the second coil 11 and compare it with the voltage the coil 1 1 should have between the terminals if that the main valve were closed (the comparison can also be made in the event that the main valve is open). As a result, the control means 7 identify if the real state of the main valve coincides with the state that corresponds to it. If this is not the case, the control means 7 detect an operational fault in the cooking appliance 1 and the display means (not shown in the figures) warn the user of said fault so that they can take the necessary steps (eg, close the gas flow manually and notify the technical service). In this simple manner, the cooking appliance 1 is able to detect possible gas leaks in an easy, efficient and economical manner.

Claims

C L A I M S

Gas cooking appliance, comprising a plurality of burners (1), an actuator (2) associated to each burner (1), which opens or closes said burner (1) when a user acts on said actuator (2), a thermocouple (4) associated to each burner (1), which generates an electrical signal when it detects a flame in the burner (1), and at least one main valve that comprises a safety system, said safety system comprising a magnetic unit (5) that is controlled according to the signals of the thermocouples

(4), characterised in that said magnetic unit

(5) is supplied directly and sequentially by the thermocouples (4) whose burners (1) have been opened by acting on the corresponding actuator (2).

Cooking appliance according to claim 1 , comprising an actuation switch (3) associated to each burner (1) that changes its state when the user acts on the corresponding actuator (2).

Cooking appliance according to claim 2, also comprising control means (7) that detect the state of the actuation switches (3) and act on supply switches (6), each supply switch

(6) being associated to a thermocouple (4).

Cooking appliance according to claim 3, wherein the magnetic unit (5) comprises a first coil (10) that is supplied directly and sequentially by the thermocouples (4) whose burners (1) have been opened by acting on the corresponding actuator (2), and a second coil (11) that is supplied by the control means

(7).

Cooking appliance according to claim 4, wherein each supply switch (6) opens or closes the flow of current (I) of the associated thermocouple (4), supplying the first coil (10) of the magnetic unit (5) when the flow of current (I) is allowed.

Cooking appliance according to any of the preceding claims, comprising at least one current sensor (8) associated to the magnetic unit (5), said current sensor (8) detecting the current (I) that reaches said magnetic unit (5) through the different thermocouples (4).

Cooking appliance according to claim 6, also comprising at least one ignition means (9) to reignit the burner (1) when said current (I) is slightly smaller than a pre-defined minimum current (IMIN) or when the slope of the current (I) is higher than a predetermined value.

8. Method for implementing a safety system in a gas cooking appliance, said gas cooking appliance (100) comprising a plurality of burners (1), an actuator (2) associated to each burner (1), which opens or closes said burner (1) when a user acts on said actuator (2), a thermocouple (4) associated to each burner (1), which generates an electrical signal when it detects a flame in the burner (1), and at least one main valve that comprises a safety system, said safety system comprising a magnetic unit (5) that is controlled according to the signals of the thermocouples (4), characterised in that by means of said method, when there is more than one burner (1) open, the magnetic unit (5) is supplied directly and sequentially by the thermocouples (4) whose associated actuator (2) has been actuated.

9. Method according to claim 8, wherein the magnetic unit (5) comprises a first coil (10) that when it is supplied keeps the main valve open, and a second coil (11) in order to detect if said main valve is open or closed when said second coil (11) is supplied.

10. Method according to claim 9, wherein when the current (I) that supplies the first coil (10) of the magnetic unit (5) is slightly smaller than a pre-defined minimum current (IMIN) or when the slope of said current (I) is higher than a predetermined value, a reignition phase is performed where ignition means (9) reignit the burners (1 ).

1 1. Method according to claim 9, wherein when the current (I) that supplies the first coil (10) of the magnetic unit (5) is slightly smaller than a pre-defined minimum current (IMIN) or when the slope of said current (I) is higher than a predetermined value, a reignition phase is performed where ignition means (9) reignit the burners (1) whose corresponding actuator (2) is actuated.

12. Method according to claims 10 or 11 , wherein said reignition phase is performed for a preset TSAFETY time and wherein when said preset TSAFETY time has ended or if the value of the current (I) that supplies the coil (10) of the magnetic unit (5) falls to an IOFF value, the main valve is closed, avoiding the passage of the gas.

13. Method according to any of claims 9 to 12, wherein when the main valve is ordered to be closed, control means (7) comprised in the cooking appliance (100) supply the second coil (1 1) through a temporary electrical current (Γ).

14. Method according to the preceding claim, wherein when the second coil (1 1) is supplied through said temporary electrical current (Γ), the control means (7) interpret the voltage difference between the terminals of said second coil (11) in order to identify if the main valve is open or closed, acting as a result of this.

15. Method according to any of claims 9 to 12, wherein if the main valve has closed because sufficient current (I) has not reached the first coil (10) in order to supply the magnetic unit (5) with some of the actuators (2) being actuated, the cooking appliance (100) is inoperative until all the burners (1) are closed, the corresponding actuators (2) being acted on for this purpose.