EP2221544B1 - Safety device for a gas appliance with a safety electro-valve - Google Patents

Description

The present invention relates to a safety device of a gas appliance.

It is particularly aimed at a safety device of a gas appliance comprising a safety solenoid valve.

It also relates to a gas cooking appliance comprising such a safety device.

In general, gas appliances, for example gas cooking appliances, comprise a safety solenoid valve adapted to pass (solenoid valve open) or to cut the passage (closed solenoid valve) of a gas flow.

Thus, in general, when the gas appliance is not in operation, the safety solenoid valve is closed, thus cutting the passage of the gas flow, and when the gas appliance is put into operation, the safety solenoid valve opens after checking that there is no malfunction in the gas appliance that may affect the safety of the appliance.

In addition, when the gas appliance is in operation and a situation likely to endanger the safety of the appliance or users is detected, the safety solenoid valve is closed to ensure the safety of the appliance. gas appliance and users.

For example, the safety solenoid valve could be disposed between a gas supply device and a gas burner of the apparatus. Thus, for example, in the event of a malfunction of the gas burner, the safety solenoid valve must be closed in order to cut the passage of the gas.

The document EP 0 441 364 describes a solenoid valve capable of closing the gas supply to the burners. The solenoid valve is controlled by a command from a microprocessor.

The figure 1 schematically represents a safety solenoid valve 1 of the state of the art which is controlled by a switch I1. This switch I1 is controlled by a control signal A.

Control means 3 generate the control signal A which controls the switch I1 which will in turn control the safety solenoid valve 1.

When the solenoid valve 1 must not pass gas (for example, when a malfunction is detected or when the gas appliance is not used), the control means 3 generate a control signal such that I1 switch is positioned in an open state so as not to supply the solenoid valve 1. Thus, the solenoid valve 1 is closed and does not let the gas.

When the safety solenoid valve 1 must let the gas through (for example when the user is using the gas appliance and there is no detected malfunction), the control means 3 generate a signal of control such that the switch I1 is positioned in the closed state so as to supply the safety solenoid valve 1. Thus, the safety solenoid valve 1 is open and lets the gas pass.

In the case where there is a failure in the control of the safety solenoid valve 1 of such a device, either at the level of the switching means, control means or the like, the opening of the safety solenoid valve 1 could be mistakenly controlled when a malfunction is present, or the closing of the safety solenoid valve 1 may not be controlled when a malfunction is present. Both of these situations are detrimental to the safety of the gas appliance and may endanger the safety of users.

The present invention aims to solve the aforementioned drawbacks and to provide a safety device of a gas appliance with a low risk of failure.

For this purpose, the present invention aims a safety device of a gas apparatus comprising a safety solenoid valve and a first switching means adapted to control the opening of the solenoid valve when in a closed state and the closure of the safety solenoid valve when it is in an open state, the positioning of said switching means in said open and closed states being a function of a first control signal. the safety device further comprising at least second and third switching means adapted to control the opening of the safety solenoid valve when in a closed state and the closing of the safety solenoid valve when they are in an open state, said at least second and third switching means being connected in series with the first switching means, and the positioning of said at least second and third switching means in said open and closed states being respectively a function of at least one second and third control signal.

According to the invention, the security device comprises processing means adapted to generate said third control signal as a function of a dynamic type signal, to detect an anomaly in at least one parameter of said dynamic type signal, and to set at a first predefined value said generated third control signal, when an abnormality in said at least one parameter is detected.

The series arrangement of said at least three switching means implies that said at least three control signals must respectively control the switching means at the same time, so that they are positioned in a closed state so that the solenoid valve security is open.

Indeed, if one of the three switching means does not control the opening of the safety solenoid valve, the safety solenoid valve remains closed.

In addition, when the safety solenoid valve is open, the positioning of at least one switching means in the open state is sufficient to close the safety solenoid valve.

With this series arrangement of the switching means and the implementation of the separate control signals for the positioning of the switching means, said at least second and third switching means constitute a redundancy of the first switching means in the control of the switching means. the opening and closing of the safety solenoid valve.

Therefore, it is possible to control the opening and closing of the safety solenoid valve, even if there is a malfunction in the control of two switching means.

Thus, this safety device meets the IEC 60335-1 standard which is the standard established by the European Committee for Standardization for household appliances. This standard requires the existence of at least duplicate security measures, ie at least two malfunctions may be present without compromising the safety of the appliance and the user.

In addition, it will be noted that the probability of the existence of a malfunction at the same time in the control of three switching means is very small.

Of course, the greater the number of switching means in series, the greater the probability of an incorrect command opening the safety solenoid valve is low. On the other hand, the larger the number of serial switching means, the higher the probability of failure of the switching means. Thus, the number of three switching means is a good compromise for obtaining a good security of the user's device.

In addition, the first predefined value to which the third control signal is attached is representative of the existence of an anomaly of the dynamic signal.

Advantageously, said processing means are adapted to compare the value of said at least one parameter with a predetermined value and to set said first predefined value to a value able to establish the third open state switching means when the value of said at least one parameter and said predetermined value are different.

Therefore, by detecting an anomaly in said at least one parameter, the value of the control signal is set to control closing of the safety solenoid valve (if it was open) or to avoid ordering by error opening the safety solenoid valve.

For example, said at least one parameter is the frequency of said dynamic type signal.

Thus, when said at least one parameter of the dynamic type signal is different from the predetermined value, there is an anomaly in the dynamic signal. Therefore, in order to avoid jeopardizing the safety of the gas appliance, the corresponding switching means is set to open state, and the solenoid valve is closed.

According to a preferred characteristic, said first, second and third control signals are of static type and said third control signal is generated by said processing means as a function of the dynamic type signal.

Therefore, the assembly formed by the second control signal and the second switching means represents a redundancy of the assembly formed by the first control signal and the first switching means.

In addition, the assembly formed by the third control signal and the third switching means represents not only a redundancy of the previous sets but also a means of checking an anomaly in the dynamic type signal.

Advantageously, first control means are adapted to generate said first control signal, and second control means are adapted to generate said dynamic type signal and said second control signal.

Thanks to this configuration, it is possible to avoid the erroneous command of the safety solenoid valve in case of malfunction of the two control means. Indeed, the dysfunction of the second control means is detected by the detection of an anomaly in at least one parameter of the dynamic type signal.

If one of the control means is faulty and a control signal is defective (control signal other than those generated by the faulty control means), it is also possible to avoid the erroneous command of the safety solenoid valve.

Therefore, it is avoided the opening of the safety solenoid valve by mistake or the omission of closing the safety solenoid valve.

According to a preferred characteristic, the safety device further comprises first and second control means adapted to generate the control signals.

There is thus a redundancy in the control means that generate the control signals controlling the opening or closing of the safety solenoid valve. Therefore, if there is a malfunction in one of the control means, there are at least second control means adapted to control the opening or closing of the safety solenoid valve.

According to a second aspect, the present invention relates to a gas appliance comprising a safety device according to the invention.

This gas appliance has advantages similar to those described above with reference to the safety device according to the invention.

The present invention finds particular application when the gas appliance is a gas boiler or a gas cooking appliance, such as a stove, a gas hob or a gas oven.

Other features and advantages of the invention will become apparent in the description below.

• la figure 1 représente un schéma fonctionnel de commande d'une électrovanne de l'art antérieur;
• la figure 2 représente schématiquement en vue de dessus un appareil à gaz comportant un dispositif de sécurité conforme à l'invention; et
• la figure 3 représente un schéma fonctionnel d'un dispositif de sécurité selon un mode de réalisation de l'invention.

In the accompanying drawings, given as non-limiting examples:

• the figure 1 represents a functional block diagram of a solenoid valve of the prior art;
• the figure 2 schematically represents a top view of a gas appliance comprising a safety device according to the invention; and
• the figure 3 represents a block diagram of a security device according to one embodiment of the invention.

We will first describe with reference to the figure 2 a type of gas appliance adapted to implement the present invention.

On the figure 2 a gas hob has been illustrated in an exploded schematic view to understand the context of the present invention.

Of course, all of these elements are integrated compactly in the gas hob.

The hob 11 comprises at least one gas burner 12, associated with an ignition means 13 located near the gas burner 12. This ignition means 13 is adapted to ignite the gas burner 12 when the latter is supplied with gas.

The hob 11 is supplied with gas through a supply line 14 which is connected to a gas source 15.

The safety device 10 according to the invention is disposed on the supply line 14. In particular, the safety solenoid valve 1 is mounted on the supply line 14 in order to allow the flow of gas to pass or cut.

The opening and closing of the safety solenoid valve 1 are controlled by means which will be described below.

We will describe with reference to the figure 3 a safety device 10 of a gas appliance comprising a safety solenoid valve 1.

The safety solenoid valve 1 is controlled by means of the switching means I1, I2, I3.

In this embodiment, the switching means I1, I2, I3 are transistors used in switching, that is to say used as switches. So at the figure 2 the transistors I1, I2, I3 are shown as switches to facilitate understanding.

Nevertheless, the switching means I1, I2, I3 may be other than a transistor.

In this embodiment, the first I1 and second I2 switching means are respectively a bipolar transistor NPN type and the third switching means I3 is a bipolar transistor PNP type.

Of course, these three transistors may be of different type. For example, the three transistors I1, I2, I3 may be identical, PNP type or NPN type.

The switching means I1, I2, I3 are arranged in series with the safety solenoid valve 1. The set of switching means I1, I2, I3 and the safety solenoid valve 1 are supplied by a supply potential Vcc.

Thus, a first terminal I1a of a first switching means I1 is connected to a reference potential 4 (here the zero potential), a second terminal I1b of the first switching means I1 is connected to a first terminal I2a of a second switching means I2. A second terminal I2b of the second switching means I2 is connected to a first terminal 1a of the safety solenoid valve 1, a second terminal 1b of the safety solenoid valve 1 is connected to a first terminal I3a of a third switching means I3, and a second terminal I3b of the third switching means I3 is connected to a supply potential Vcc.

Of course the serial connection order of the switching means I1, I2, I3 and the safety solenoid valve 1 could be different.

In fact, this electrical diagram is a particular arrangement of the transistors with respect to the safety solenoid valve 1. In other embodiments, the three switching means I1, I2, I3 could be arranged upstream of the solenoid valve. security 1. Thus, the three switching means I1, I2, I3 would be connected to each other, one of the end switching means being connected to the supply potential Vcc and another of the end switching means being connected to the safety solenoid valve 1, the safety solenoid valve 1 being connected in turn to the reference potential 4.

The switching means I1, I2, I3 can be in an open state or in a closed state.

Thus, since the switching means I1, I2, I3 are arranged in series, when one of the switching means I1, I2, I3 is open, the safety solenoid valve 1 is not energized. Therefore, the safety solenoid valve 1 is closed and does not let gas into the supply line 14 to the burner 12.

On the contrary, the switching means I1, I2, I3 must be simultaneously in the closed state so that the safety solenoid valve 1 is energized and is open, thus allowing gas to flow into the supply line 14 to the burner 12.

First A, second B and third C control signals respectively control the first I1, second I2, and third I3 switching means.

The first A, second B and third C control signals are static type signals, i.e. they have a continuous value. In this example, the control signals A, B, C may have two possible values, a first predefined value and a second predefined value. The first predefined value is a value able to establish the corresponding switching means in open state and the second predefined value is a value able to establish the corresponding switching means in closed state.

In this example, the first and second predefined values of the control signals A, B, C may have a value of 0V or 5V.

By way of non-limiting example, the reference potential 4 has a value of 0V, and the supply potential Vcc has a value of 5V or 12V, 24V or 48V, this value being a function of the type of safety solenoid valve 1 .

Of course, the values of the control signals A, B, C able to control the switching means I1, I2, I3 are a function of the type of switching means. This is well known to those skilled in the art.

Thus, in this example, the first I1 and the second I2 switching means are bipolar transistors NPN type. Thus, the first predefined value is 0V (NPN transistor in open state), and the second predefined value is 5V (NPN transistor in closed state).

Note that in this example, the third switching means I3 is a bipolar transistor PNP type. Thus, the first predefined value is 5V (PNP transistor in open state), and the second predefined value is 0V (PNP transistor in closed state).

Here, when the control signals A, B, C have the first predefined value (here of 0V for the first A and second B control signals and 5V for the third control signal C) the switching means I1, I2, I3 corresponding are in open state. On the contrary, when the control signals A, B, C have the second predefined value (here of 5V for the first A and the second B control signals and 0V for the third control signal C) the switching means I1, I2, I3 corresponding are in closed condition.

In this example, the first control signal A is generated by first control means 3, and the second control signal B is generated by second control means 3A.

The third control signal C is generated by processing means 5 as a function of a dynamic type signal Cd which is generated by the second control means 3A (this will be described below).

Thus, in this architecture of the safety device 1, the second and third switching means I2 and I3, as well as the second control means 3A constitute a redundancy respectively of the first switching means I1 and the first control means 3. This redundancy allows to avoid an incorrect control of the safety solenoid valve 1 to ensure the safety of a gas appliance containing such a safety device 10, as well as a user of this gas appliance.

Possible faults that might be present in the security device 10 are shown in dotted lines.

• défauts d1, d2, d3 concernant les moyens de commutation I1, I2, 13, par exemple un court-circuit d1, d2, d3 des moyens de commutation I1, I2, I3,
• défauts d4, d5, d6, d7 concernant les signaux de commande A, B, C ou le signal de type dynamique Cd, par exemple un court-circuit d4, d5, d6, d7 des signaux de commande A, B, C, ou du signal de type dynamique Cd à un potentiel fixe, par exemple le potentiel d'alimentation Vcc ou le potentiel de référence 4, ou
• un dysfonctionnement (non représenté à la figure 3) des moyens de contrôle 3, 3A.

Thus, the three main defects that may be present are:

• defects d1, d2, d3 concerning the switching means I1, I2, 13, for example a short-circuit d1, d2, d3 switching means I1, I2, I3,
• faults d4, d5, d6, d7 concerning the control signals A, B, C or the dynamic type signal Cd, for example a short-circuit d4, d5, d6, d7 of the control signals A, B, C, or a dynamic potential signal Cd at a fixed potential, for example the supply potential Vcc or the reference potential 4, or
• a malfunction (not shown in figure 3 ) control means 3, 3A.

The safety device 10 described makes it possible to avoid an erroneous command of the safety solenoid valve 1 in the presence of two of these faults at the same time.

Thus, for example, when a fault d1, d2, d3 concerning the switching means 11, 12, 13 is present in two of them, a third provides the opening or closing function of the safety solenoid valve 1 In the same way, when a fault d4, d5, d6 concerning the control signals A, B, C is present in two of them, the third control signal controls the switching means 11, 12, 13 corresponding to control the safety solenoid valve 1.

When a fault d1, d2, d3 concerning the switching means I1, I2, I3 is present in one of them and at the same time a fault d4, d5, d6 concerning the control signals A, B, C is present in one of them, a switching means and a control signal controls the safety solenoid valve 1.

Thus, for example if the first switching means I1 has a fault d1, and the second control signal B has a fault d5, the third switching means I3 and the third control signal C ensure the control of the safety solenoid valve. 1.

The detection of a fault concerning a malfunction in the second control means 3A is provided by the processing means 5.

As described above, the processing means 5 generate the third control signal C as a function of a dynamic type signal Cd.

In this embodiment, the first 3 and second 3A control means are respectively first 3 and second 3A microcontrollers, and the dynamic type signal Cd is a square type periodic signal generated by the second control means 3A when the Safety solenoid valve 1 must be open, that is to say that the switching means 11, 12, 13 must be closed at the same time.

When the safety solenoid valve 1 must be closed, that is to say that at least one of the switching means 11, 12, 13 must be open, the dynamic type signal Cd has a constant value.

Of course, in other embodiments, second control means 3A could generate other types of periodic signals, for example, sinusoidal or triangular.

In this example, when the dynamic type signal Cd is generated by the second microcontroller 3A and the second microcontroller 3A (control means in charge of generating the dynamic type signal Cd) does not exhibit a malfunction, the signal of the type Cd generated dynamics, being a digital signal, is a square periodic signal, the signal parameters having predetermined values.

In this example, the dynamic signal Cd has two levels, a first level or low level (here of 0V) and a second level or high level (here of 5V), the value of the frequency of the dynamic signal Cd is substantially 8kHz, may have a tolerance of +/- 1kHz, and the duty cycle is 50% with a tolerance of +/- 20%.

The processing means 5 are adapted to detect an anomaly in at least one of the parameters of the dynamic type signal Cd. In this example, the parameters are the frequency and the duty cycle.

When there is a malfunction in the second control means 3A, the dynamic type signal Cd has a constant value (zero frequency), or it is defective (frequency and / or duty cycle erroneous).

Here, this detection is implemented by comparing the value of said at least one parameter with a predetermined value for this parameter.

When the value of said at least one parameter for which the comparison is made is not substantially similar to the predetermined value for that at least one parameter, an abnormality in said at least one parameter is detected. Thus, the processing means 5 generate the third control signal C and set its value to a first predefined value able to establish the third switching means 13 in the open state.

When during this comparison, the value of said at least one parameter is substantially similar to the predetermined value for this at least one parameter, the processing means 5 generate the third signal of C command and set its value to a second preset value adapted to establish the third switch means I3 in closed state.

This comparison is made taking into account a certain tolerance for the values of the parameters. The values of the tolerances for these parameters are given above by way of non-limiting example.

In addition, when a fault d7 concerning the dynamic type signal Cd, for example a short-circuit at the supply potential Vcc, is present, the processing means 5 generate the third control signal C and set its value to the first predefined value adapted to establish the third switching means 13 in open state.

Therefore, when a malfunction is present in the second control means 3A, closing the safety solenoid valve 1 is controlled, thus not jeopardizing the safety of a gas appliance containing such a safety device 10 and a user of such a gas appliance.

Thus, thanks to this architecture comprising two control means 3, 3A, the first control means 3 generating the first control signal A, and the second control means 3A generating the second control signal B and the dynamic signal Cd, when a malfunction is present in the first control means 3, and a second fault is present in the second B or the third C control signal, or in the second 12 or third 13 switching means, either the second 12 or the third switching means 13 provide control of the safety solenoid valve 1.

In addition, when a malfunction is present at the same time in the first 3 and second 3A control means, the closure of the safety solenoid valve 1 is controlled, following the detection of the malfunction of the second control means 3A through the signal dynamic type Cd and processing means 5.

Therefore, the presence of two defects does not jeopardize the safety of a gas appliance containing such a safety device 10 and a user of such a gas appliance.

In this example, the first 3 and second 3A control means are interconnected by a communication link 7. This communication link 7 is used for the communication between the control means 3, 3A, and can be used for example by the first control means 3 to communicate to the second control means 3A that they have a malfunction or they have detected a malfunction in other elements of the gas appliance, or vice versa.

Thus, thanks to the invention, it is possible to control the opening and closing of the safety solenoid valve, even when two faults concerning the switching means, the control signals and the control means are present at the same time. .

Thus, the opening of the safety solenoid valve by mistake or the omission of the closure of the safety solenoid valve is avoided, thereby ensuring the safety of an apparatus containing a safety device according to the invention and a safety device. user of such a device.

Thus, the security device may comprise a greater number of switching means and control means.

Furthermore, the safety device can be used in various gas appliances, for example in a gas oven, a gas hob or a boiler.

Claims (8)

1. Safety device (10) for a gas appliance, comprising a safety solenoid valve (1) and a first switching means (I1) able to control the opening of the safety solenoid valve (1) when it is in a closed state and the closure of the safety solenoid valve (1) when it is in an open state, the positioning of said switching means (I1) in said open and closed states being dependent on a first control signal (A), the safety device (10) further comprising at least second (12) and third (13) switching means able to control the opening of the safety solenoid valve (1) when they are in a closed state and the closure of the safety solenoid valve (1) when they are in an open state, said at least second (12) and third (13) switching means being connected in series with the first switching means (I1), and the positioning of said at least second (12) and third (13) switching means in said open and closed states being dependent respectively on at least a second (B) and a third (C) control signal, the safety device being characterised in that it further comprises processing means (5) able to generate said third control signal (C) according to a signal of the dynamic type (Cd), to detect an abnormality in at least one parameter of said dynamic signal (Cd), and to fix at a first predefined value said generated third control signal (C), when an abnormality in said at least one parameter is detected.
2. Safety device (10) according to claim 1, characterised in that said processing means (5) are able to compare the value of said at least one parameter with a predetermined value and to fix said first predefined value at a value able to establish said third switching means (13) in the open state when the value of said at least one parameter and said predetermined value are different.
3. Safety device (10) according to one of claims 1 or 2, characterised in that said at least one parameter is the frequency of said signal of the dynamic type (Cd).
4. Safety device (10) according to one of claims 1 to 3, characterised in that said first (A), second (B) and third (C) control signals are of the static type and said third control signal (C) is generated by said processing means (5) according to the dynamic signal (Cd).
5. Safety device (10) according to one of claims 1 to 4, characterised in that first control means (3) are able to generate said first control signal (A), and second control means (3A) are able to generate said signal of the dynamic type (Cd) and said second control signal (B).
6. Safety device (10) according to claim 1, characterised in that it further comprises first (3) and second (3A) control means able to generate said control signals (A, B, C) .
7. Safety device (10) according to one of claims 5 or 6, characterised in that said first (3) and second (3A) control means are connected together by a communication link (7).
8. Gas appliance comprising a safety device (10) according to one of claims 1 to 7.

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