CN108072056B

CN108072056B - Gas appliance

Info

Publication number: CN108072056B
Application number: CN201710265032.8A
Authority: CN
Inventors: F·克雷赫达·安杜埃萨; J·I·艾拉斯蒂·巴蒂奥拉
Original assignee: Coprecichina Co ltd; Copreci SCL
Current assignee: Coprecichina Co ltd; Copreci SCL
Priority date: 2016-11-16
Filing date: 2017-04-21
Publication date: 2020-10-30
Anticipated expiration: 2037-04-21
Also published as: KR102406763B1; ES2668231A1; ES2668231B1; KR20180055726A; CN108072056A

Abstract

A gas appliance. Gas appliance comprising at least one gas burner (10), a gas valve (20), the gas valve (20) comprising: a magnetic device; a main coil (33), the main coil (33) being connected to the thermocouple (60); and an auxiliary coil (34), the auxiliary coil (34) being connected to the magnetic means; and a manual actuator (40), the manual actuator (40) acting on the magnetic means to open the gas passage, the gas appliance (200) comprising a control unit (100) connected to the auxiliary coil (34) and an electric switch (70) connected to the control unit (100). By acting on the manual actuator (40), the electric switch (70) is activated and the control unit (100) applies a pulsating voltage to the auxiliary coil (34) to generate a current signal that enables the detection of the opening of the gas passage from the variation of the inductance of the auxiliary coil (34).

Description

Gas appliance

Technical Field

The present invention relates to gas appliances (gas appliances), and more particularly, to gas cookers.

Background

Gas appliances, in particular gas cookers, are known which comprise at least one gas burner and (for each gas burner) a gas valve having a gas inlet conduit and a gas outlet conduit, from which gas is supplied to the gas burner. The gas valve includes a solenoid valve for opening or closing a gas passage to a gas burner, the solenoid valve including a magnetic closure member (magnetic closure member), a magnetic core, a main coil electrically connected to a thermocouple disposed next to the gas burner and wound on the magnetic core. The gas valve also comprises a manual actuator acting on the magnetic closure member to open a gas passage through the solenoid valve when the manual actuator is axially operated. When acting on the manual actuator, the gas passage to the gas burner is opened and a flame can be ignited in said burner. As long as the flame remains active, heating the thermocouple with the flame causes an electromotive force to be generated in the main coil, which makes it possible to keep the magnetic closing member and the magnetic core attached to each other, and therefore the gas passage through the solenoid valve is open.

The known gas appliance also comprises means for very rapidly opening the gas passage through the solenoid valve. CN1439849A describes a gas appliance comprising at least one gas burner and a gas valve for each burner, said gas valve comprising a solenoid valve comprising magnetic means (magnetic means) for keeping open a gas passage to the burner (said magnetic means comprising a magnetic closure member and a magnetic core), a primary coil wound on the magnetic core and electrically connected to a thermocouple arranged next to the gas burner, and a secondary coil wound on the magnetic core. The gas valve also comprises a manual actuator acting on the magnetic closure member to open the gas passage when the manual actuator is axially moved. The gas appliance also comprises a control unit electrically connected to the auxiliary coil and an electric switch electrically connected to the control unit, said control unit providing, when the electric switch is activated, a current signal circulating through the auxiliary coil, said current signal enabling to keep the gas passage open.

In order to ignite a flame in the burner of a gas appliance, the user must press the manual actuator to open the gas passage in the solenoid valve to the gas burner and activate the electric switch, so that the control unit provides a current signal to the auxiliary coil and keeps the gas passage open until the flame is ignited by the ignition means. After ignition of the flame, the main coil is a coil that makes it possible to keep the gas channel open by means of heating the thermocouple with the flame.

Disclosure of Invention

The invention aims to provide a gas appliance.

The gas appliance of the present invention comprises at least one gas burner and a gas valve for each burner, said gas valve comprising a solenoid valve comprising magnetic means for keeping open a gas passage to the burner (said magnetic means comprising a magnetic closure member and a magnetic core), a primary coil electrically connected to a thermocouple arranged next to the gas burner and wound on the magnetic core, and a secondary coil wound on the magnetic core. The gas valve further comprises a manual actuator which acts on the magnetic closure member to open the gas passage when the manual actuator is axially moved. The gas appliance also comprises a control unit electrically connected to the auxiliary coil and an electric switch electrically connected to the control unit, said control unit providing, when the electric switch is activated, a current signal circulating through the auxiliary coil, said current signal enabling to keep the gas passage open.

When the manual actuator is moved axially, the electric switch is activated and a control unit applies a pulsating voltage to the auxiliary coil to generate a current signal, the control unit detecting the opening of the gas passage according to a change in the inductance value in the auxiliary coil.

Clause 1. a gas appliance comprising at least one gas burner (10) and a gas valve (20) for each burner (10), said gas valve (20) comprising a solenoid valve (30) and a manual actuator (40), said solenoid valve comprising: -magnetic means (31, 32) for keeping open a gas passage (21) to the burner (10), said magnetic means (31, 32) comprising a magnetic closing member (31) and a magnetic core (32); a primary coil (33), the primary coil (33) being electrically connected to a thermocouple (60) arranged next to a burner (10) and wound on the magnetic core (32); -an auxiliary coil (34), the auxiliary coil (34) being wound on the magnetic core (32), the manual actuator (40) acting on the magnetic closing member (31) to open the gas channel (21) upon axial movement of the manual actuator (40), the gas appliance (200) further comprising a control unit (100) electrically connected to the auxiliary coil (34) and an electric switch (70) electrically connected to the control unit (100), the control unit (100) providing, when the electric switch (70) is activated, a current signal (i) circulating through the auxiliary coil (34), the current signal (i) enabling to keep the gas channel (21) open, characterized in that, when the manual actuator (40) is axially moved, the electric switch (70) is activated and the control unit (100) applies a pulsating voltage (Vp) to the auxiliary coil (34), to generate said current signal (i), said control unit (100) detecting the opening of said gas channel (21) as a function of the variation of the inductance value in said auxiliary coil (34).

Clause 2. the gas appliance of clause 1, wherein the pulsating voltage (Vp) overlaps the current signal (i).

Clause 3. the gas appliance according to clause 1, wherein the change in the inductance value in the auxiliary coil (34) is detected by checking the evolution of a current signal (i) circulating through the auxiliary coil (34).

Clause 4. the gas appliance according to clause 3, wherein the current signal (i) is checked after each electrical pulse of the pulsating voltage (Vp).

Clause 5. the gas appliance according to clause 4, wherein the pulsating voltage (Vp) has a duration (t), the current signal (i) being checked at a time (t1) after each electrical pulse, the control unit detecting that the gas channel (21) is open because the checked current signal (i) changes from a value (Ic) greater than a reference current (Ir) to a value (Ia) less than the reference current (Ir) between successive electrical pulses due to a change in the inductance value in the auxiliary coil (34).

Clause 6. the gas appliance according to clause 4, wherein the pulsating voltage (Vp) has a duration (t), the current signal (i) being checked at a time (t1) after each electric pulse, the control unit (100) detecting that the gas channel (21) is open because the checked current signal (i) decreases in successive pulses to a value (Ia) corresponding to the open position of the gas channel (21) due to a change in the inductance value in the auxiliary coil (34).

Clause 7. the gas appliance of clause 5 or 6, wherein the pulsed voltage (Vp) is applied for a time (t) of between about 5 seconds and about 10 seconds.

Clause 8. the gas appliance according to any one of clauses 1 to 6, wherein, when the control unit (100) detects a change in the inductance value in the secondary coil (34), the control unit (100) acts on a spark generator (50) to generate a spark train (spark train) (51) for igniting a flame in the burner (10) until the end of the time (t) of the pulsating voltage (Vp).

Clause 9. the gas appliance according to any one of clauses 1 to 6, wherein the primary coil (33) is electrically connected to the control unit (100) by an electrical connection (72), the control unit (100) acting on a spark generator (50) to generate a spark train (51) for igniting a flame in the burner (10) when the control unit (100) detects a change in the inductance value in the secondary coil (34), and the control unit (100) stopping acting on the spark generator (50) when the electromotive force generated by the thermocouple (60) in the primary coil (33) as the flame heats up reaches a predetermined threshold voltage value (Vt).

Clause 10. the gas appliance according to clause 9, wherein the control unit (100) stops applying the pulsating voltage (Vp) to the auxiliary coil (34) when the electromotive force generated by the thermocouple (60) in the main coil (33) reaches the threshold voltage value (Vt).

Clause 11. the gas appliance according to clause 10, wherein, when the electromotive force generated by the thermocouple (60) in the primary coil (33) falls from a rated voltage value (Vn) to a minimum threshold voltage value (Vtm), the control unit (100) applies the pulsating voltage (Vp) to the secondary coil (34) for a time (t '), the control unit (100) acting on the spark generator (50) to generate a spark train (51) for igniting a flame in the burner (10), until the end of the time (t') of the pulsating signal (Vp), the electromotive force generated by the thermocouple (60) in the primary coil (33) restores the rated voltage value (Vn).

Clause 12. the gas appliance according to clause 10, wherein, when the electromotive force generated by the thermocouple (60) in the primary coil (33) falls from a rated voltage value (Vn) to a minimum threshold voltage value (Vtm), the control unit (100) applies the pulsating voltage (Vp) to the secondary coil (34) for a time (t '), the control unit (100) acts on the spark generator (50) to generate a spark train (51) for igniting a flame in the burner (10) until the end of the time (t ') of the pulsating signal (Vp) so as to reach the rated voltage value (Vn), and when the electromotive force generated by the thermocouple (60) falls to a minimum voltage value (Vm), the control unit (100) then applies a voltage (V ') having a polarity opposite to that of the pulsating voltage (Vp) to the secondary coil (34), to close said gas channel (21).

When the manual actuator is pressed, the user cannot determine that the gas passage in the solenoid valve is open because the user does not fully press the manual actuator, or because the gas valve has some problem preventing the manual actuator from being fully pressed. In this case, even when the electric switch is activated so that the control unit supplies the current signal to the auxiliary coil, if the gas channel is not open, the auxiliary coil cannot keep the gas channel open, and the main coil cannot keep the gas channel open since there is no flame in the gas burner.

The gas appliance of the present invention detects the opening of the gas passage according to the change in the inductance value in the auxiliary coil when or after the manual actuator is pressed to activate the electric switch, and the control unit applies a pulsating voltage to the auxiliary coil using a signal from the electric switch to generate a current signal. In this way, if the magnetic closing member is in contact with the magnetic core when the manual actuator is pressed, the auxiliary coil will have a first inductance value and thus the current signal will have a first value. If the magnetic closing member is not in contact with the magnetic core when the manual actuator is pressed, the auxiliary coil will have a second inductance value different from said first inductance value and said current signal will have a second value different from said first value. Therefore, the control unit of the gas appliance detects whether the gas passage is open or not in a simple manner.

These and other advantages and features of the invention will become apparent in view of the drawings and detailed description of the invention.

Drawings

Fig. 1 shows an overall solution of an embodiment of a gas appliance according to the invention.

Fig. 2 shows a partial version of the gas valve of the gas appliance of fig. 1, in which the manual actuator is not actuated and the gas passage of the solenoid valve is closed.

Fig. 3 shows a partial version of the gas valve of the gas appliance of fig. 1, in which the manual actuator is actuated and the gas passage of the solenoid valve is open.

Fig. 4a shows a diagram of a signal of a pulsating voltage applied to an auxiliary coil by a control unit of the gas appliance of fig. 1.

Fig. 4b shows a graph of the current signal generated by the pulsating voltage of fig. 4a when the magnetic devices are in contact, the signal of the pulsating voltage being in phase with the current signal.

Fig. 4c shows a diagram of the current signal generated by the pulsating voltage of fig. 4a when the magnetic means are disengaged, the signal of the pulsating voltage being in phase with the current signal.

Fig. 5 shows a diagram of a sequence for igniting the burner of the gas appliance of fig. 1, wherein the gas appliance does not comprise flame detection.

Fig. 6 shows a diagram of a sequence for igniting a burner of the gas appliance of fig. 1, wherein the gas appliance comprises a flame detection.

Fig. 7 shows a diagram of a sequence for re-igniting the gas burner of the gas appliance of fig. 1.

Fig. 8 shows a diagram of a sequence for re-igniting the gas burner of the gas appliance of fig. 1 and subsequently closing the gas channel.

Detailed Description

Fig. 1 shows an overall solution of an embodiment of a gas appliance 200 according to the invention. Fig. 2 shows a partial version of the gas valve 20 of the gas appliance 200 of fig. 1, wherein the manual actuator 40 is not actuated and the gas channel 21 of the solenoid valve 30 is closed. Fig. 3 shows a partial version of the gas valve 20 of the gas appliance 200 of fig. 1, in which the manual actuator 40 is actuated and the gas channel 21 of the solenoid valve 30 is open. Fig. 4a shows a graph of the signal of the pulsating voltage Vp applied to the auxiliary coil 34 by the control unit 100 of the gas appliance 200 of fig. 1, fig. 4b shows a graph of the current signal i generated by the pulsating voltage Vp when the

magnetic means

31, 32 are in contact, the signal of the pulsating voltage Vp being in phase with the current signal i, and fig. 4c shows a graph of the current signal i generated by the pulsating voltage Vp when the

magnetic means

31, 32 are separated, the signal of the pulsating voltage Vp being in phase with the current signal i.

The embodiment of the gas appliance 200 of the illustrated invention comprises a gas burner 10 with ignition of a flame and a container thereon, and a gas valve 20 for said burner 10. The gas valve 20 comprises a gas inlet conduit 22 feeding said gas valve 20 from a supply (not shown in the figures) and a gas outlet conduit 23 fluidly connected to the gas burner 10 and enabling feeding of gas to the gas burner 10. The gas valve 20 comprises a solenoid valve 30, said solenoid valve 30 comprising, in a conventional manner, magnetic means 31, 32 enabling to keep open the gas passage 21 towards the gas burner 10 and a main coil 33. The magnetic means 31, 32 include a magnetic closing member 31 and a magnetic core 32, and the main coil 33 is electrically connected to the thermocouple 60 disposed next to the burner 10 and wound on the magnetic core 32. The solenoid valve 30 also comprises a second coil, which is an auxiliary coil 34, wound on the magnetic core 32, similarly to the main coil 33.

The gas valve 20 further comprises a manual actuator 40, said manual actuator 40 being coupled to the magnetic closure member 31 in this embodiment of the gas appliance 200. When the manual actuator 40 is not actuated, the magnetic closing member 31 closes the gas passage 21, for example, with the aid of a spring (not shown in the drawings). When the manual actuator 40 is axially pressed and moved by acting on the manual actuator 40, it acts on the magnetic closing member 31, moving it, and the gas passage 21 opens when overcoming the force of the spring.

The gas valve 20 comprises a rotary member (not shown in the figures) arranged in the gas flow inside said gas valve 20, between the solenoid valve 30 and the gas outlet conduit 23, to which a manual actuator 40 is coupled, said rotary member enabling the regulation of the gas flow towards the gas burner 10. In the conventional gas valve having the magnetic device and the main coil, when a user wants to ignite a flame in the gas burner, they press the manual actuator to open a gas passage in the electromagnetic valve toward the gas burner, and then rotate the gas actuator by means of the rotating member so that a flow of gas is supplied to the gas burner. By using some ignition means, the user ignites the flame in the burner while continuously pressing the manual actuator, and after a certain time they can stop actuating the manual actuator, since after igniting the flame, by heating the thermocouple with the flame, the main coil will be the coil that enables keeping the gas channel open by means of the electromotive force generated (fem, below) (since said fem generates a magnetic field that enables keeping the magnetic means in contact and making the gas channel open). However, this way of igniting the flame in a gas burner is slow, since the fem produced gradually increases until a voltage value is reached which is sufficient to keep the magnetic means in contact.

As described above, the gas appliance 200 includes the auxiliary coil 34. The gas appliance 200 further comprises a control unit 100 electrically connected to the auxiliary coil 34 and an electric switch 70 further electrically connected to the control unit 100. In this embodiment of the gas appliance 200, the electrical switch 70 is arranged such that when the manual actuator 40 is axially moved, it closes the electrical switch 70, an activation signal 71 reaching the control unit 100. When the control unit 100 is activated by means of the activation signal 71, said control unit 100 provides a current signal i circulating through the auxiliary coil 34. This current signal i makes it possible to quickly keep the gas channel 21 open, so that the user can release the manual actuator 40 earlier. Since the current signal immediately circulates through the auxiliary coil, a magnetic field is rapidly generated which makes it possible to keep the

magnetic means

31, 32 attached to each other, the magnetic core 32 attracting the magnetic closing member 31 and thus opening the gas channel 21. The flame ignition operation is carried out as described above, producing fem in the main coil which eventually keeps the gas channel 21 open. Finally, the present invention relates to assisting in the rapid ignition of a flame in a gas burner 10.

However, the user himself may find some situations in which they cannot determine that the gas passage 21 in the solenoid valve 30 is open, either because they do not fully press the manual actuator 40, ensuring that the

means

31, 32 are in contact and thus ensuring that the gas passage 21 is open, or because the gas valve 20 has some problem (such as dirt, wear, etc.) preventing the manual actuator 40 from being fully pressed. In this case, even when the electric switch 70 is activated so that the control unit 100 provides the current signal i to the auxiliary coil 34, if the gas channel 21 is not opened and the

magnetic means

31, 32 are not in contact, the auxiliary coil 34 cannot generate a magnetic field capable of attracting the

magnetic means

31, 32 and opening the gas channel 21. Since the flame cannot be ignited in the gas burner 10, the main coil 33 does not generate fem and also cannot keep the gas channel 21 open.

However, the gas appliance 200 of the present invention detects the opening of the gas passage 21 according to the change in the inductance value in the auxiliary coil 34. By acting on the manual actuator 40 and after activating the electric switch 70, the control unit 100 is activated by the activation signal 71 from the electric switch 70 and applies the pulsating voltage Vp to the auxiliary coil 34 to generate the current signal i. In this way, if the magnetic closing member 31 is in contact with the magnetic core 32 when the manual actuator 40 is pressed, the auxiliary coil 34 will have a first inductance value and thus the current signal i will have a first value. If the magnetic closing member 31 is not in contact with the magnetic core 32 when the manual actuator 40 is pressed, the auxiliary coil 34 will have a second inductance value different from said first inductance value and the current signal i will have a second value different from said first value. Therefore, the control unit 100 of the gas appliance 200 knows whether the gas channel 21 is open before making any other decision.

As shown in fig. 4, in this embodiment of the gas appliance 200, the signal of the pulsating voltage Vp overlaps the current signal i (i.e., they are in phase). The pulsating voltage Vp signal is an electric pulse square wave signal (square signal) having a continuous pulsating voltage value Vp exceeding a positive continuous voltage value. The pulsating voltage Vp has a frequency comprised between 10Hz and 1kHz, in a preferred embodiment a pulsating voltage Vp of 20Hz is used.

The variation of the inductance value in the auxiliary coil 34 when passing from the condition in which the manual actuator 40 is not actuated to the condition in which said manual actuator 40 is actuated to open the gas channel 21 is detected by the control unit 100, said control unit 100 checking the evolution of the value of the current signal i circulating through said auxiliary coil 34, said current signal i being checked after each electric pulse of the pulsating voltage Vp.

The pulsating voltage Vp is applied to the secondary coil 34 for a time t, at a sampling time t after each electrical pulse₁The current signal i is checked. When there is a variation of the inductance value in the auxiliary coil 34 through which the checked current signal i passes, the control unit 100 preferably detects the opening of the gas channel 21 between successive electrical pulses from a current value Ic greater than the reference current Ir to a current value Ia smaller than said reference current Ir. The value of the reference current Ir, which is a value clearly distinguishing the opening and closing conditions of the gas channel 21 and therefore the contact or separation conditions of said

magnetic means

31, 32, is a value predetermined by the manufacturer of the gas appliance 200 according to the characteristics of the auxiliary coil 34 and of the

magnetic means

31, 32.

Another way of detecting the opening of the gas channel 21 using the control unit 100 is at a sampling time t after each electrical pulse₁The value of the current signal i is checked, which decreases in successive pulses to a current value Ia corresponding to the open position of the gas channel 21.

The application time t of the pulsating voltage Vp may have a value of, for example, between about 5 seconds and about 10 seconds.

Fig. 5 shows a diagram of a sequence for igniting a burner 10 of a gas appliance (not shown in the figures) similar to the gas appliance 200 of fig. 1, but not including flame detection. The gas appliance comprises a spark generator 50 arranged next to the gas burner 10 and electrically connected to a control unit 100. When the gas appliance does not comprise any type of rapid actuation flame detection (for example, an ionization system or using fem generated by the main coil 33 with the control unit 100), the sequence of igniting a flame in the gas burner 10 starts with pressing and thus axially moving the manual actuator 40.

By pressing the manual actuator 40, the electrical switch 70 is first closed and the activation signal 71 reaches the control unit 100. When the control unit 100 is activated by means of the activation signal 71, said control unit 100 applies a pulsating voltage Vp to the auxiliary coil 34 for a time t₁The pulsating voltage Vp generates a current signal i that circulates through the auxiliary coil 34. When the manual actuator 40 is completely moved, the magnetic closing member 31 and the magnetic core 32 are in contact, and the inductance value of the auxiliary coil 34 is at time t_LAnd (6) changing. In this embodiment of the gas appliance 200, the user rotates the manual actuator 40 after pressing the manual actuator 40 so that gas can pass through the outlet duct 23 to the gas burner 10. At time t for detecting change in inductance value_LThe control unit 100 then acts on the spark generator 50 to generate a spark train 51 for igniting a flame in the gas burner 10, said spark train 51 having a duration from the instant t_LUntil the end of the time t of the pulsating voltage Vp. Once the flame is ignited in the gas burner 10, the thermocouple 60 is heated and fem is gradually generated in the main coil 33 until fem reaches a voltage value close to the nominal value Vn (and fem is always greater than the minimum threshold Vtm defined by the manufacturer of the gas appliance 200), this time coinciding with the application of the pulsed voltage Vp and the end of the spark train 51.

Fig. 6 shows a diagram of a sequence for igniting the burner 10 of the gas appliance 200 of fig. 1, wherein the gas appliance 200 comprises a flame detection and further comprises a spark generator 50 arranged next to the gas burner 10 and electrically connected to the control unit 100. The flame detection of the gas appliance 200 comprises an electrical connection 72 to the wires of the thermocouple 60 and main coil 33 assembly, so that fem generated by said main coil 33 allows sending an electrical signal to the control unit 100, said control unit 100 comprising means for detecting said signal (not shown in the figures). The sequence for igniting a flame in the gas burner 10 starts with pressing and thus axially moving the manual actuator 40.

By pressing the manual actuator 40, the electrical switch 70 is first closed and the activation signal 71 reaches the control unit 100. When the control unit 100 is activated by means of an activation signal71, the control unit 100 applies a pulsating voltage Vp to the auxiliary coil 34, which generates a current signal i that circulates through the auxiliary coil 34. When the manual actuator 40 is completely moved, the magnetic closing member 31 and the magnetic core 32 are in contact, and the inductance value of the auxiliary coil 34 is at time t_LAnd (6) changing. After pressing the manual actuator 40, the user rotates said manual actuator 40 so that the gas can go to the gas burner 10 through the outlet duct 23. At time t for detecting change in inductance value_LThe control unit 100 then acts on the spark generator 50 to generate a spark train 51 for igniting a flame in the gas burner 10. Once the flame is ignited in the gas burner 10, the thermocouple 60 is heated and fem is gradually generated in the main coil 33. When said fem reaches a predetermined threshold voltage value Vt, which is lower than the nominal voltage value Vn for normal operation of the main coil 33, the control unit 100 learns, by means of the electric signal reached by means of the electric connection 72, that said threshold voltage value Vt is sufficient to keep the gas channel 21 open, thus keeping the

magnetic means

31, 32 in contact and stopping acting on the spark generator 50. In this embodiment of the gas appliance 200, at the same time, the control unit 100 also stops applying the pulsating voltage Vp to the auxiliary coil 34. Therefore, the electric consumption is limited to realizing the threshold voltage value Vt in the primary coil 33.

Once the flame is ignited in the gas burner 10, cooking can be performed. However, problems may arise with respect to the flame of the burner 10. Fig. 7 shows a diagram of a sequence for re-igniting the gas burner 10 of the gas appliance 200 of fig. 1, wherein in said gas appliance 200 the control unit 100 is electrically connected to the main coil 33. If the case in which the flame of the gas burner 10 is extinguished, for example, by wind, or if the flame is not extinguished and wind, for example, diffuses the flame in the burner 10, resulting in failure to heat the thermocouple 60 or insufficient heating of the thermocouple 60, the effect is that fem and thus the rated voltage value Vn in the main coil 33 start to drop.

When fem generated in the main coil 33 drops from the nominal voltage value Vn to the minimum threshold voltage value Vtm, the control unit 100 applies a pulsating voltage Vp to the auxiliary coil 34 to keep the

magnetic means

31, 32 in contact and the gas channel 21 open, and simultaneously acts on the spark generator 50 to generate the spark train 51 for a time t', which is also defined by the manufacturer of the gas appliance 200 in accordance with safety standards. If the problem concerns the extinguishing of the flame of the gas burner 10, the spark string 51 enables the flame to be reignited, the thermocouple 60 is heated again, and the nominal voltage value Vn of the main coil 33 at fem is restored, which enables the gas channel 21 to be kept open. Another way for assessing the flame-out condition of the gas burner 10 using the control unit 100 is to define in said control unit 100 a gradient in which the voltage value in the primary coil 33 decreases at a specific time, and a gradient (not shown in the figures) in which the voltage value in the primary coil 33 increases at a specific time, so that at the time defined to reach said values, the control unit 100 applies the pulsating voltage Vp on the secondary coil 34 and simultaneously on the spark generator 50, and stops acting respectively.

Fig. 8 shows a diagram of a sequence for re-igniting the gas burner 10 of the gas appliance 200 of fig. 1 and subsequently closing the gas channel 21, wherein in said gas appliance 200 the control unit 100 is electrically connected to the main coil 33. Unlike the above-described sequence of re-ignition, it may occur that the gas burner 10 cannot be re-ignited even if different attempts are made. In this case, and for safety reasons, it is advisable to close the gas channel 21 as soon as possible.

When fem generated in the main coil 33 drops from the nominal voltage value Vn to a minimum threshold voltage value Vtm defined by the manufacturer of the gas appliance 200, the control unit 100 applies a pulsating voltage Vp to the auxiliary coil 34 to keep the

magnetic means

31, 32 in contact and the gas channel 21 open, and simultaneously acts on the spark generator 50 to generate the spark train 51 for a time t'. If the problem relates to the extinguishing of the flame of the gas burner 10, but the spark string 51 does not enable the flame to be re-ignited, the nominal voltage value Vn of fem of the main coil 33 will continue to drop. When fem generated by thermocouple 60 reaches the minimum voltage value Vm, control unit 100 applies to auxiliary coil 34 a voltage V' having a polarity opposite to that of pulsating voltage Vp and having a value such that magnetic means 31, 32 can be separated, so that gas passage 21 is quickly closed and gas no longer reaches gas burner 10. When the control unit 100 applies the voltage V' to the auxiliary coil 34, the control unit 100 may simultaneously emit an audible and/or visual signal that enables an indication to the user that an abnormality has occurred, and in this case enables a notification to the user that the gas valve 20 must be closed by rotating the manual actuator 40 to the closed (OFF) position.

Also in this case, and as mentioned above, for the re-ignition sequence, the control unit 100 can evaluate the flame-out condition of the gas burner 10 by means of a gradient defining the voltage value in the main coil 33 to decrease at a certain time. If a certain gradient of voltage drop occurs after a certain time, the control unit 100 may interpret this as the spark string 51 failing to re-ignite the flame in the gas burner 10.

Claims

1. A gas appliance comprising at least one gas burner (10) and a gas valve (20) for each burner (10), the gas valve (20) comprising a solenoid valve (30) and a manual actuator (40), the solenoid valve (30) comprising: -magnetic means (31, 32) for keeping open a gas passage (21) to the burner (10), said magnetic means (31, 32) comprising a magnetic closing member (31) and a magnetic core (32); a primary coil (33), the primary coil (33) being electrically connected to a thermocouple (60) arranged next to the burner (10) and wound on the magnetic core (32); -an auxiliary coil (34), the auxiliary coil (34) being wound on the magnetic core (32), the manual actuator (40) acting on the magnetic closing member (31) to open the gas channel (21) when the manual actuator (40) is axially moved, the gas appliance (200) further comprising a control unit (100) electrically connected to the auxiliary coil (34) and an electric switch (70) electrically connected to the control unit (100), the control unit (100) providing, when the electric switch (70) is activated, a current signal (i) circulating through the auxiliary coil (34), the current signal (i) enabling to keep the gas channel (21) open, characterized in that, when the manual actuator (40) is axially moved, the electric switch (70) is activated and the control unit (100) applies a pulsating voltage (Vp) to the auxiliary coil (34), to generate said current signal (i), said control unit (100) detecting the opening of said gas channel (21) as a function of the variation of the inductance value in said auxiliary coil (34).

2. Gas appliance according to claim 1, wherein the pulsating voltage (Vp) is in phase with the current signal (i).

3. Gas appliance according to claim 1, wherein the variation of the inductance value in the auxiliary coil (34) is detected by checking the evolution of the current signal (i) circulating through the auxiliary coil (34).

4. Gas appliance according to claim 3, wherein the current signal (i) is checked after each electrical pulse of the pulsating voltage (Vp).

5. Gas appliance according to claim 4, wherein the pulsating voltage (Vp) has a duration t, at a time (t) after each electric pulse₁) Checking said current signal (i), said control unit (100) detecting that said gas channel (21) is open, because the checked current signal (i) changes from a value (Ic) greater than a reference current (Ir) to a value (Ia) less than said reference current (Ir) between successive electrical pulses due to a variation in said inductance value in said auxiliary coil (34).

6. Gas appliance according to claim 4, wherein the pulsating voltage (Vp) has a duration t, at a time (t) after each electric pulse₁) -checking the current signal (i), the control unit (100) detecting that the gas channel (21) is open, because the checked current signal (i) decreases in successive pulses to a value (Ia) corresponding to the open position of the gas channel (21) due to the variation of the inductance value in the auxiliary coil (34).

7. Gas appliance according to claim 5 or 6, wherein said pulsating voltage (Vp) is applied for a time t between 5 and 10 seconds.

8. Gas appliance according to any one of claims 1 to 6, wherein, when said control unit (100) detects a variation of said inductance value in said auxiliary coil (34), said control unit (100) acts on a spark generator (50) to generate a spark train (51) for igniting a flame in said burner (10) until the end of time t of said pulsating voltage (Vp).

9. Gas appliance according to any one of claims 1 to 6, wherein said primary coil (33) is electrically connected to said control unit (100) by means of an electrical connection (72), said control unit (100) acting on a spark generator (50) to generate a spark train (51) for igniting a flame in said burner (10) when said control unit (100) detects a variation of said inductance value in said secondary coil (34), and said control unit (100) stopping acting on said spark generator (50) when the electromotive force generated by said thermocouple (60) in said primary coil (33) following the heating of said flame reaches a predetermined threshold voltage value (Vt).

10. Gas appliance according to claim 9, wherein the control unit (100) stops the application of said pulsating voltage (Vp) to the auxiliary coil (34) when the electromotive force generated by the thermocouple (60) in the primary coil (33) reaches said threshold voltage value (Vt).

11. Gas appliance according to claim 10, wherein, when the electromotive force generated by the thermocouple (60) in the primary coil (33) drops from a nominal voltage value (Vn) to a minimum threshold voltage value (Vtm), the control unit (100) applies the pulsating voltage (Vp) to the secondary coil (34) for a time t ', the control unit (100) acting on the spark generator (50) to generate a spark train (51) for igniting a flame in the burner (10), the electromotive force generated by the thermocouple (60) in the primary coil (33) restoring the nominal voltage value (Vn) until the end of the time t' of the pulsating voltage (Vp).

12. Gas appliance according to claim 10, wherein the control unit (100) applies the pulsating voltage (Vp) to the secondary coil (34) for a time t ' when the electromotive force generated by the thermocouple (60) in the primary coil (33) drops from a nominal voltage value (Vn) to a minimum threshold voltage value (Vtm), the control unit (100) acting on the spark generator (50) to generate a spark train (51) for igniting a flame in the burner (10) until the end of the time t ' of the pulsating voltage (Vp) in order to reach the nominal voltage value (Vn), and the control unit (100) then applies to the secondary coil (34) a voltage (V ') having a polarity opposite to that of the pulsating voltage (Vp) when the electromotive force generated by the thermocouple (60) drops to a minimum voltage value (Vm), to close said gas channel (21).