Patent Description:
Cooking appliances with burners, each of which having associated therewith a thermocouple connected to a respective electromagnetic valve are known in the state of the art, such that when the thermocouple detects the presence of flame in the burner, it generates a thermoelectric current which is capable of keeping the electromagnetic valve energized at a given time, allowing the passage of gas to the corresponding burner.

<CIT> furthermore describes electric circuits in which a MOSFET is arranged between the thermocouple and the electromagnetic valve, said MOSFET acting like a switch, such that depending on pre-established parameters, the MOSFET can open the circuit preventing the passage of current to the electromagnetic valve, and therefore causing the electromagnetic valve to close the passage of gas to the burner regardless of the presence of flame in the corresponding burner.

Moreover, powering thermoelectric circuits of this type with power supplies including transformers for galvanically isolating said thermoelectric circuits is also known, as described in <CIT>.

<CIT> discloses a switch off control for gas heating points of a cooking appliance connected to AC mains with a switch for an electrical device, the gas heating points being each secured by means of a thermocouple which, when the respective gas heating point is in operation, current is passed through a winding of an electromagnet which keeps the valve open allowing gas to pass through. The control further includes a charging circuit controlled by a rectifying semiconductor circuit with a capacitor. The capacitor is charged via the semiconductor circuit when the switch is opened, briefly energising the winding of the electromagnet against the current direction of the thermocouple by means of this charging. The circuit makes it possible to switch off the gas heating points by means of program switches used for electric heating points.

<CIT> discloses a control device for gas appliances including a timing function, for example for enabling setting and/or detection of a time interval for supplying gas to a respective burner. The control device comprises a circuit arrangement including a first control module including a switching circuit electrically connected between an electromagnet and a thermoelectric generator of a safety valve of a gas tap, a second control module including a control circuit that comprises a wireless communication circuit electrically connected to the control circuit and configured for exchange of signals in wireless mode with a remote electronic programing device, a third control module centralizing the functions of timing and driving the switching circuit, and a power supply module including power supply means. The power supply module is designed to be installed in a position remote from the first control module. The second and third control modules are installed in a position remote from the other modules. The first control module which is the one to be associated to the gas tap, may be simplified from the structural standpoint since it is no longer indispensable for it to be mechanically fixed to the body of a corresponding tap.

The object of the invention is to provide a thermoelectric assembly for powering a plurality of electromagnetic valves of a cooking appliance, each electromagnetic valve being configured for closing the passage of gas to a corresponding burner of the cooking appliance, as defined in the claims.

The thermoelectric assembly according to the invention comprises a main current circuit associated with a respective electromagnetic valve, the main current circuit comprising a thermocouple configured for detecting flame in the corresponding burner, a cable connected to the thermocouple and configured for electrically connecting said thermocouple with the corresponding electromagnetic valve, and a transistor connected to the cable and configured for de-energizing the electromagnetic valve.

The main current circuit comprises a connection module comprising a power supply connected to the transistor, input terminals configured for being connected to an external energy source, a rectifier configured for transforming the alternating current of the external energy source into direct current, and a resistive block connected between one of the input terminals and the rectifier and configured for minimizing the current circulating through the power supply to a value that ensures a galvanic isolation.

A thermoelectric assembly having a main current circuit with a basic and simple power supply is thereby obtained, without having to include a transformer in said power supply for obtaining the required galvanic isolation. The power supply will thus be simpler and more cost-effective, and is therefore integrated in the main current circuit, particularly in the connection module together with the transistor. A main current circuit that is compact, simple, and can be readily connected to the external energy source is thereby obtained.

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

<FIG> shows a thermoelectric assembly <NUM> according to the invention suitable for powering a plurality of electromagnetic valves <NUM> and <NUM>' of a cooking appliance (not depicted in the drawings), each electromagnetic valve <NUM> and <NUM>' being configured for closing the passage of gas to a corresponding burner (not depicted in the drawings) of the cooking appliance.

The thermoelectric assembly <NUM> comprises a main current circuit <NUM> associated with a respective electromagnetic valve <NUM>. The main current circuit <NUM> comprises a thermocouple <NUM> configured for detecting flame in the corresponding burner, cables <NUM> and <NUM> connected to the thermocouple <NUM> and configured for electrically connecting said thermocouple <NUM> with the corresponding electromagnetic valve <NUM> through a connector <NUM>, a transistor <NUM> connected to one of the cables <NUM> and configured for de-energizing the electromagnetic valve <NUM>, and a connection module <NUM> comprising a power supply <NUM> connected to the transistor <NUM>.

The transistor <NUM> is a field-effect transistor, preferably a MOSFET type transistor. The transistor <NUM> comprises a port terminal 9a, a drain terminal 9b, and a source terminal 9c, said transistor <NUM> being connected to the power supply <NUM> through the port terminal 9a and source terminal 9c. The transistor <NUM> behaves like a switch. In particular, when it operates in the cut-off region conduction between the source terminal 9c and the drain terminal 9b does not occur, so it operates like an open switch regardless of whether or not the thermocouple <NUM> detects the presence of flame, and therefore the electromagnetic valve is kept de-energized, preventing the passage of gas to the corresponding burner. When the power supply <NUM> is connected to the external energy source <NUM>, it powers the transistor <NUM> which operates like a closed switch, the electromagnetic valve is kept energized as long as the thermocouple <NUM> detects flame in the burner and a thermoelectric current capable of keeping the electromagnetic valve energized is generated. The transistor <NUM> has two connection terminals <NUM> and <NUM>, each of which is connected to the cable <NUM> of the thermocouple <NUM>.

The power supply <NUM> comprises two input terminals <NUM> and <NUM> configured for being connected to the external energy source <NUM>, a rectifier <NUM> configured for transforming the alternating current of the external energy source <NUM> into direct current, and a resistive block <NUM> connected between one of the input terminals <NUM> and <NUM> and the rectifier <NUM>, the resistive block <NUM> being configured for minimizing the current circulating through the power supply <NUM> to a value equivalent to the galvanic isolation. The resistance of the resistive block <NUM> is about <NUM> megaohms.

In the embodiment shown in the drawings, the power supply <NUM> comprises two resistive blocks <NUM>, each of them connected to the corresponding input terminal <NUM> and <NUM>. Preferably, each resistive block <NUM> comprises at least two resistors 14a and 14b arranged such that they are connected in series. The resistance resulting from the two resistive blocks <NUM> is about <NUM> megaohms.

The power supply <NUM> further comprises capacitance filters <NUM> connected in parallel to one another and in parallel to the rectifier <NUM>, the capacitance filters <NUM> being configured for filtering or smoothing out ripple, resulting in a direct current whose voltage would virtually not vary over time. The power supply <NUM> further comprises a diode <NUM> connected in parallel to the rectifier <NUM> and to the capacitance filters <NUM>. In a preferred embodiment, the rectifier <NUM> is a diode bridge.

Moreover, the first input terminal <NUM> and the second input terminal <NUM> of the power supply <NUM> are configured for being connected with the external energy source <NUM>, providing a form-fitting connection with the external energy source <NUM>. This form-fitting connection is a simple and quick assembly/disassembly connection. In a preferred embodiment, the first input terminal <NUM> and the second input terminal <NUM> of the main current circuit <NUM> are configured for being connected, providing a male-female attachment.

The connection module <NUM> of the main current circuit <NUM>, shown in <FIG>, comprises a body <NUM> inside which there is housed the power supply <NUM> and the transistor <NUM>, with the input terminals <NUM> and <NUM> projecting from the body <NUM>. The body <NUM> is made of an insulating material and comprises a corresponding cover <NUM> which closes the housing where the power supply <NUM> and the transistor <NUM> are arranged.

In the embodiment shown in the drawings, the power supply <NUM> and the transistor <NUM> are assembled on a PCB (not depicted) housed inside the body <NUM>.

The power supply <NUM> comprises an output terminal <NUM> projecting from the body <NUM>. The input terminals <NUM> and <NUM> and the output terminal <NUM> project towards the outside orthogonal to the cover <NUM>.

The connection module <NUM> of the main current circuit <NUM> may comprise an additional output terminal (not depicted) configured for connecting with a presence sensor for detecting the presence of utensils associated with the corresponding burner. Said additional output terminal will provide a form-fitting connection with the corresponding presence sensor.

The main current circuit <NUM> further comprises a discharge resistor <NUM> of the transistor, said discharge resistor <NUM> being connected in parallel to the transistor <NUM>, said discharge resistor <NUM> assuring the opening of the transistor <NUM> when said transistor <NUM> is no longer powered by the power supply <NUM>. The discharge resistor <NUM> is arranged such that it is housed in the body <NUM> of the connection module <NUM>. In particular, the discharge resistor <NUM> is assembled on the PCB together with the transistor <NUM> and the power supply <NUM>.

The main current circuit <NUM> also comprises a safety resistor <NUM> connected in series with the port 9a of the transistor <NUM>. Said safety resistor <NUM> limits the current that would go to the main current circuit <NUM> from the power supply <NUM> in the event of a short-circuit failure of the transistor <NUM>. The discharge resistor <NUM> is arranged such that it is housed in the body <NUM> of the connection module <NUM>. In particular, the discharge resistor <NUM> is assembled on the PCB together with the transistor <NUM> and the power supply <NUM>.

Moreover, an electromechanical switch <NUM> is arranged between the power supply <NUM> and the power supply external <NUM>.

In other embodiments not shown in the drawings, the switch <NUM> can be connected between the power supply <NUM> and the transistor <NUM>. In that case, the connection module <NUM> houses the switch <NUM> in the body <NUM>. In one embodiment, the switch <NUM> is assembled on the PCB housed inside the body <NUM>.

In both cases, when the switch <NUM> is closed and the power supply <NUM> is connected to the external energy source <NUM>, the power supply <NUM> powers the transistor <NUM> such that the transistor <NUM> allows current to pass therethrough. With the switch <NUM> closed, if the thermocouple <NUM> detects the presence of flame, it will generate a thermoelectric current that goes through the transistor <NUM> keeping the electromagnetic valve <NUM> such that it allows the passage of gas to the burner. When the thermocouple <NUM> does not detect any flame, and therefore no longer generate the thermoelectric current required for keeping the electromagnetic valve <NUM> energized, said electromagnetic valve <NUM> closes the passage of gas. When the corresponding signal is sent to the switch <NUM> from a non-depicted control so as to open said switch <NUM>, the transistor <NUM> is not powered, so it acts like an open switch, not allowing current to go from the thermocouple <NUM> to the electromagnetic valve <NUM>, the passage of gas is thereby closed. The transistor <NUM> therefore allows acting on the electromagnetic valve <NUM> de-energizing it when a previously defined parameter is achieved, said parameter not being the presence of flame in the burner <NUM>.

The thermoelectric assembly <NUM> further comprises at least one additional current circuit <NUM>' associated with a respective electromagnetic valve <NUM>', said additional current circuit <NUM>' being able to be connected to the main current circuit <NUM>. In the embodiment shown in the drawings, the thermoelectric assembly <NUM> comprises two additional current circuits <NUM>', each of them associated with a respective electromagnetic valve <NUM>'. Regardless of whether the thermoelectric assembly <NUM> includes one, two, or a plurality of additional current circuits, the features of each additional current circuit are similar and will be described below.

Each additional current circuit <NUM>' comprises a thermocouple <NUM>' configured for detecting flame in the corresponding burner, cables <NUM>' and <NUM>' connected to the corresponding thermocouple <NUM>' and configured for electrically connecting said thermocouple <NUM>' with the corresponding electromagnetic valve <NUM>' through a connector <NUM>', and a transistor <NUM>' connected to the corresponding cable <NUM>' and configured for de-energizing the electromagnetic valve <NUM>' to which it is connected.

Each transistor <NUM>' of the respective additional current circuit <NUM>' has the same features and operates in the same manner as the transistor <NUM> of the main current circuit <NUM>, so what has been described above is applicable to the transistors of the additional current circuits. The features of the thermocouple <NUM>' of each additional current circuit <NUM>' are similar to those of thermocouple <NUM>. Similarly, the features of the cables <NUM>' and <NUM>' for connecting the thermocouple <NUM>' to the electromagnetic valve <NUM>' in the additional current circuit <NUM>' are similar to those of the cables <NUM> and <NUM> of the main current circuit <NUM>, so what is described above in relation to these elements for the main current circuit is applicable to the additional current circuits.

Each additional current circuit <NUM>' comprises a connection module <NUM>' housing the corresponding transistor <NUM>', each connection module <NUM>' comprising an input terminal <NUM>' connected to the corresponding transistor <NUM>'. In particular, the input terminal <NUM>' is connected to the port 9a' of the respective transistor <NUM>'. The connection module <NUM>' of each additional current circuit <NUM>', shown in <FIG> and <FIG>, comprises an output terminal <NUM>'. Each input terminal <NUM>' of the corresponding additional current circuit <NUM>' is configured for being connected to the output terminal <NUM> of the connection module <NUM> of the main current circuit <NUM> or to the output terminal <NUM>' of another connection module <NUM>' of the additional current circuit <NUM>'.

In the embodiment shown in the drawings, one of the additional current circuits <NUM>' (hereinafter, first additional current circuit <NUM>') is connected to the main current circuit <NUM> through respective connection modules <NUM> and <NUM>'. In particular, the input terminal <NUM>' of the connection module <NUM>' of the first additional current circuit <NUM>' is connected to the output terminal <NUM> of the main current circuit <NUM> as shown in <FIG>. Furthermore, both additional current circuits <NUM>' and <NUM>" are connected to one another through respective connection modules <NUM>'. In particular, the input terminal <NUM>' of the connection module <NUM>' of another additional current circuit <NUM>" (hereinafter, second additional current circuit <NUM>") is connected to the output terminal <NUM>' of the connection module <NUM>' of the first additional current circuit <NUM>'.

The output terminal <NUM> of the connection module <NUM> of the main current circuit <NUM> and the input terminal <NUM>' of the connection module <NUM>' of an additional current circuit <NUM>' are configured for being connected, providing a form-fitting connection. This form-fitting connection is a simple and quick assembly/disassembly connection. In a preferred embodiment, the output terminal <NUM> of the connection module <NUM> of the main current circuit <NUM> and the input terminal <NUM>' of the connection module <NUM>' of the first additional current circuit <NUM>' are configured for being connected, providing a male-female attachment.

Moreover, the output terminal <NUM>' of the connection module <NUM>' of the first additional current circuit <NUM>' and the input terminal <NUM>' of the connection module <NUM>' of the second additional current circuit <NUM>' are configured for being connected, providing a form-fitting connection. This form-fitting connection is a simple and quick assembly/disassembly connection. In a preferred embodiment, the output terminal <NUM>' of the connection module <NUM>' of the first additional current circuit <NUM> and the input terminal <NUM>' of the connection module <NUM>' of the second additional current circuit <NUM>' are configured for being connected, providing a male-female attachment.

The connection module <NUM>' of each additional current circuit <NUM>' comprises a body <NUM>' inside which there is housed the respective transistor <NUM>', with the input terminal <NUM>' and the respective output terminal <NUM>' projecting towards the outside of the respective body <NUM>'. Each body <NUM>' is made of an insulating material. Each body <NUM>' comprises a corresponding cover <NUM>' which closes the corresponding housing. In the embodiment shown in the drawings, the input terminal <NUM>' and the output terminal <NUM>' of the connection module <NUM>' of the corresponding additional current circuit <NUM>' project towards the outside orthogonal to the cover <NUM>'.

The connection module <NUM>' of each additional current circuit <NUM>' may comprise an additional output terminal (not depicted) configured for connecting with a presence sensor for detecting the presence of utensils associated with the corresponding burner. Said additional output terminal will provide a form-fitting connection with the corresponding presence sensor.

Each additional current circuit <NUM>' further comprises a discharge resistor <NUM>' of the transistor <NUM>', said discharge resistor <NUM>' being connected in parallel to the transistor <NUM>' and configured for assuring the opening of the transistor <NUM>' when said transistor <NUM>' is no longer powered by the power supply <NUM>. The discharge resistor <NUM>' is arranged such that it is housed in the body <NUM>' of the connection module <NUM>'. In particular, the discharge resistor <NUM>' is assembled on the PCB together with the transistor <NUM>'.

Each additional current circuit <NUM>' comprises a safety resistor <NUM> connected in series with the port 9a' of the transistor <NUM>' and configured for limiting the current that would go to the additional current circuit <NUM>' from the power supply <NUM> in the event of a short-circuit failure of the corresponding transistor <NUM>'. The discharge resistor <NUM>' is arranged such that it is housed in the body <NUM>' of the respective connection module <NUM>'. In particular, the discharge resistor <NUM>' is assembled on the PCB together with the respective transistor <NUM>'.

Each additional current circuit <NUM>' further comprises a diode <NUM>' connected between the discharge resistor <NUM>' and the safety resistor <NUM>, and in parallel to the transistor <NUM>'.

In the embodiment shown in the drawings, the output terminal <NUM>' of the connection module <NUM>' of the corresponding additional current circuit <NUM>' is connected between the discharge resistor <NUM>' of the additional current circuit <NUM>' and the safety resistor <NUM>' of the respective additional current circuit <NUM>'.

In other embodiments that are not shown, the thermoelectric assembly may comprise a single additional current circuit or a plurality of additional current circuits that can be connected to one another through respective connection modules, the single additional current circuit or a circuit of the plurality of additional current circuits being arranged such that it is connected to the main current circuit. A thermoelectric assembly in which the circuits associated with the thermocouples can be quickly coupled to one another is thereby obtained, with the power supply being integrated in one of said circuits. A modular solution that can be scaled according to needs and readily detachable from one another is thereby provided. The features of the single additional current circuit or of each of the additional current circuits of the plurality of additional current circuits are those described for the two additional current circuits of the embodiment shown in the drawings.

Claim 1:
Thermoelectric assembly for powering a plurality of electromagnetic valves (<NUM>, <NUM>') of a cooking appliance, each electromagnetic valve (<NUM>, <NUM>') being configured for closing the passage of gas to a corresponding burner of the cooking appliance, the thermoelectric assembly (<NUM>) comprising a main current circuit (<NUM>) associated with a respective electromagnetic valve (<NUM>), the main current circuit (<NUM>) comprising a thermocouple (<NUM>) configured for detecting flame in the corresponding burner, a cable (<NUM>) connected to the thermocouple (<NUM>) and configured for electrically connecting said thermocouple (<NUM>) with the corresponding electromagnetic valve (<NUM>), a transistor (<NUM>) connected to the cable (<NUM>) and configured for de-energizing the electromagnetic valve (<NUM>), and a connection module (<NUM>) comprising a power supply (<NUM>) connected to the transistor (<NUM>), the power supply (<NUM>) comprising input terminals (<NUM>,<NUM>) configured for being connected to an external energy source (<NUM>), and a rectifier (<NUM>) configured for transforming the alternating current of the external energy source (<NUM>) into direct current, characterized in that the connection module (<NUM>) further comprises a resistive block (<NUM>) connected between one of the input terminals (<NUM>, <NUM>) of the power supply (<NUM>) and the rectifier (<NUM>), the resistive block (<NUM>) being configured for minimizing the current circulating through the power supply (<NUM>) to a value that ensures a galvanic isolation that otherwise would have been provided by a transformer.