Indication apparatus to indicate the output level of a pilot flame and method

Abstract

The present invention concerns an indication apparatus and corresponding method to indicate the output level of a pilot flame in a gas appliance provided with a thermocouple suitable to convert the energy generated by a pilot flame, which receives gas from a pilot valve, into electric voltage to power an electro valve of the pilot valve and to keep the latter open. The apparatus comprises a first and a second connector suitable to be coupled with a positive terminal and with a negative terminal of the thermocouple, a voltage measurement circuit connected to the first and the second connector, a lighting device configured to provide a light signal, a controller device coupled with the voltage measurement circuit and with the lighting device and configured to determine the switching on of the lighting device on the basis of the output supplied by the voltage measurement circuit to provide a user with an indication of when the voltage generated by the thermocouple is greater than or equal to a predefined value sufficient to power the electro valve.

1 . An indication apparatus to indicate the output level of a pilot flame in a gas appliance provided with a thermocouple suitable to convert the energy generated by a pilot flame, which receives gas from a pilot valve, into electric voltage to power an electro valve of the pilot valve and to keep the latter open, characterized in that said apparatus comprises:
 a first and a second connector suitable to be coupled with a positive terminal and with a negative terminal of the thermocouple;   a voltage measurement circuit connected to said first and second connectors and configured to calculate the difference in electric voltage at the heads of the terminals to determine the electric voltage generated by the thermocouple and to provide an output correlated to the difference in voltage calculated;   a lighting device configured to provide a light signal;   a controller device coupled with the voltage measurement circuit and with the lighting device and configured to determine the switching on of said lighting device on the basis of the output supplied by the voltage measurement circuit to provide a user with an indication of when the voltage generated by the thermocouple is greater than or equal to a predefined value sufficient to power the electro valve;   a battery connected to said controller device, and configured to power the latter and the voltage measurement circuit, and   a power circuit connected between said connectors and said lighting device, and comprising a capacitor configured to accumulate a quantity of electric charge supplied by the thermocouple at least sufficient to allow the switching on of said lighting device, said power circuit being configured to power the latter with the electric voltage supplied by said capacitor on the basis of commands received from said controller device in such a way as to switch on said lighting device in a flashing manner when the voltage generated by the thermocouple is greater than or equal to said predefined value.   
     
     
         2 . The indication apparatus of  claim 1 , wherein said power circuit comprises a second switch connected in series to said lighting device, which can be selectively activated/deactivated by said controller device in order to respectively allow/prevent the electric charge accumulated in said capacitor being discharged through said lighting device. 
     
     
         3 . The indication apparatus of  claim 2 , wherein said indication apparatus comprises a transformer configured to raise the electric voltage generated by the thermocouple and provided with a primary coil connected to the first and to the second connector, and with a secondary coil connected to the heads of said lighting device, wherein said capacitor is connected in parallel between said secondary coil and said lighting device, and is configured to accumulate the electric voltage supplied by said transformer. 
     
     
         4 . The indication apparatus of  claim 3 , wherein said power circuit comprises a first switch connected in series to said primary coil, which can be selectively activated/deactivated by said controller device in order to respectively allow/prevent the passage of current through it to provide the transformer with an alternating electric current. 
     
     
         5 . The indication apparatus as in any of  claim 1 , wherein said capacitor is connected to said battery by means of a resistor having a resistance value such as to prevent the switching on of said lighting device only by means of said battery. 
     
     
         6 . The indication apparatus of  claim 1 , wherein said voltage measurement circuit comprises an operational amplifier connectable by means of the first connector and the second connector to the positive and negative terminals of the thermocouple, and is configured to calculate the difference in electric voltage between the two terminals, and to supply said controller device with an output signal correlated to the difference in electric voltage calculated. 
     
     
         7 . The indication apparatus of  claim 1 , wherein said controller device is connected by means of a first circuit branch to said battery and by means of a second circuit branch to said power circuit, wherein said first branch and said second branch are connected in a common node. 
     
     
         8 . A gas appliance comprising a valve device configured to supply a flow of gas to a main burner and to a pilot burner, and provided with a pilot valve which can be driven manually with a manual drive device by means of which a user can take it to an open condition to allow the passage of the gas through it, and a electro valve configured to keep it in the open condition when it is powered with sufficient voltage, and with a thermocouple configured to convert the heat supplied by a pilot flame of the pilot burner into an electric voltage suitable to power the electro valve to keep the pilot valve open, characterized in that said gas appliance comprises the indication apparatus of  claim 1  connected to the terminals of said thermocouple. 
     
     
         9 . A method to indicate the output level of a pilot flame in a gas appliance provided with a thermocouple suitable to convert the energy generated by a pilot flame, which receives gas from a pilot valve, into an electric voltage suitable to power an electro valve of the pilot valve and to keep the latter open, characterized in that said method comprises:
 detecting an electric voltage at the terminals of the thermocouple by means of a voltage measurement circuit;   calculating the difference in electric voltage between the two terminals, and providing a controller device with an output signal correlated to the difference in electric voltage calculated in order to determine the electric voltage generated by the thermocouple;   comparing the electric voltage generated by the thermocouple with predefined reference values and, when said electric voltage is equal to or greater than a first predefined value, insufficient to power the electro valve, accumulating in a capacitor of a power circuit connected between said thermocouple and said lighting device a quantity of electric charge, supplied by said thermocouple, and suitable to switch on a lighting device;   keeping monitored said electric voltage generated by the thermocouple and said quantity of electric charge accumulated in the power circuit,   wherein the method provides to:   power said voltage measurement circuit and said controller device by means of a battery;   command, by means of said controller device, said power circuit in order to supply said lighting device with said quantity of accumulated electric charge so that it flashes, when the electric voltage generated by the thermocouple is greater than or equal to a second predefined value, sufficient to power the electro valve, and the quantity of electric charge accumulated is sufficient to switch on said lighting device.   
     
     
         10 . The method of  claim 9 , said method provides to accumulate said electric charge in said capacitor by means of a transformer connected between the thermocouple and the capacitor, wherein the method provides to selectively activate and/or deactivate a first switch connected in series to a primary coil of said transformer by means of said controller device in order to respectively allow and/or prevent the passage of current through it to provide the transformer with an alternating electric current when the voltage generated by the thermocouple is greater than or equal to the first predefined value. 
     
     
         11 . The method in of  claim 10 , wherein, in order to switch on the lighting device ( 22 ) with said quantity of accumulated electric charge, the method provides to activate a second switch, connected in series to said lighting device, by means of said controller device, to allow the electric charge accumulated in said capacitor to discharge through said lighting device and switch on the latter. 
     
     
         12 . The method  claim 10 , wherein said method provides to pre-charge said capacitor with a quantity of charge provided by said battery at the moment said battery is installed. 
     
     
         13 . The method of  claim 9 , further comprising powering said controller device by means of the power circuit with the energy supplied by said thermocouple, when, under normal working conditions, the electric voltage of said power circuit is greater than the electric voltage of said battery.