Device and method for controlling a fuel-oxidizer mixture in a premix gas burner

Abstract

A method for controlling a fuel-oxidizer mixture in a premix gas burner includes: receiving a flame signal representing the presence of a flame deriving from the combustion of a fuel of a first predetermined type or a second predetermined type inside a combustion cell; accessing fuel data representing the fact that the gas fuel belongs to the first type or the second type; generating drive signals to control a gas flow regulating valve that supplies gas to the burner and to control a rotation speed of a fan configured to take in oxidative air; sending the drive signals to the gas flow regulating valve and to a motor connected to the fan. A memory unit contains first regulation data and second regulation data and is programmed to generate the drive signals based on the first regulation data or on the second regulation data, depending on the fuel data.

What is claimed is: 
     
         1 . A method for controlling a fuel-oxidizer mixture in a premix gas burner comprising the following steps performed by a processor:
 receiving a flame signal, representing the presence of a flame deriving from the combustion of a fuel belonging to a first predetermined type or a second predetermined type inside a combustion cell of the burner   accessing fuel data, representing the fact that the gas fuel belongs to the first type or the second type;   generating drive signals, to control a gas flow regulating valve that supplies gas to the burner and to control a rotation speed of a fan configured to take in oxidative air; and   sending the drive signals to the gas flow regulating valve and to a motor connected to the fan;   wherein the processor has access to a memory unit containing first regulation data and second regulation data different from the first regulation data and is programmed to generate the drive signals based on the first regulation data or, alternatively, on the second regulation data depending on the fuel data.   
     
     
         2 . The method according to  claim 1 , wherein the step of receiving the flame signal comprises the following steps:
 receiving a first flame signal, representing the presence of a flame deriving from the combustion of a fuel of the first type; and   receiving a second flame signal, representing the presence of a flame deriving from the combustion of a fuel of the second type;   wherein the processor generates the drive signals based on the first flame signal and/or on the second flame signal.   
     
     
         3 . The method according to  claim 2 , wherein the method comprises a step of processing the first flame signal and the second flame signal to derive the fuel data representing a presence of fuel of the first type and/or a presence of fuel of the second type. 
     
     
         4 . The method according to  claim 3 , wherein the fuel data represent a quantity of fuel of the first type and/or a quantity of fuel of the second type. 
     
     
         5 . The method according to  claim 4 , wherein, if the quantity of the first fuel is greater than a first value, the processor performs the following steps:
 deriving a quantitative ratio between the fuel and the oxidizer based on the first flame signal; and   comparing the derived quantitative ratio with an ideal quantitative ratio, and wherein the processor generates the drive signals based on the comparison between the derived quantitative ratio and the ideal quantitative ratio.   
     
     
         6 . The method according to  claim 5 , comprising a step of receiving at least one temperature signal representing a temperature inside a combustion cell of the burner and wherein the processor derives the quantitative ratio between the fuel and the oxidizer based also on the temperature signal. 
     
     
         7 . The method according to  claim 2 , wherein the processor calculates, for the first and/or the second flame signal a first and/or a second value of signal intensity, and wherein the processor compares the first and/or the second intensity value with reference data that represent:
 an association between the first intensity value and the quantity of fuel of the first type; and/or   an association between the second intensity value and the quantity of fuel of the second type.   
     
     
         8 . The method according to  claim 2 , comprising the following steps:
 receiving a flow rate signal, identifying a gas flow rate detected by a gas flow sensor;   determining a gas flow rate as a function of the flow rate signal;   comparing the quantity of fuel of the first type and/or the quantity of fuel of the second type, calculated on the basis of the first and the second flame signal with the gas flow rate calculated on the basis of the flow rate signal; and   performing a diagnostic test on the gas flow sensor based on the comparison.   
     
     
         9 . The method according to  claim 2 , wherein the fuel of the first type comprises hydrogen and wherein the first flame signal represents:
 an electromagnetic wave in the ultraviolet field or at least one temperature in the combustion cell; and   wherein the fuel of the second type comprises methane and/or LPG and the second flame signal representative of a direct current due to ionization of an electrode or of the flame impedance.   
     
     
         10 . The method according to  claim 1 , comprising a step of receiving a flow rate signal identifying a gas flow rate detected by a gas flow or pressure sensor and wherein the processor derives the fuel data also on the basis of the flow rate signal. 
     
     
         11 . The method according to  claim 1 , comprising a step of receiving at least one temperature signal representing a temperature inside a combustion cell of the burner and wherein the processor is able to confirm that the burner is on based on the flame signal and on the temperature signal. 
     
     
         12 . The method according to  claim 1 , wherein the fuel data are received by the processor through manual entry by a user from a user interface. 
     
     
         13 . A method for controlling a fuel-oxidizer mixture in a premix gas burner comprising the following steps performed by a processor:
 receiving a flame signal representing the presence of a flame deriving from the combustion of a fuel belonging to a first predetermined type or a second predetermined type inside a combustion cell of the burner;   accessing fuel data representing the fact that the gas fuel belongs to the first type or the second type;   generating drive signals to control a gas flow regulating valve that supplies gas to the burner and to control a rotation speed of a fan configured to take in oxidative air;   sending the drive signals to the gas flow regulating valve and to a motor connected to the fan; and   receiving a flow rate signal identifying a gas flow rate detected by a gas flow or pressure sensor;   wherein the processor derives the fuel data also on the basis of the flow rate signal.   
     
     
         14 . A method for controlling a fuel-oxidizer mixture in a premix gas burner comprising the following steps performed by a processor:
 receiving a flame signal representing the presence of a flame deriving from the combustion of a fuel belonging to a first predetermined type or a second predetermined type inside a combustion cell of the burner;   accessing fuel data representing the fact that the gas fuel belongs to the first type or the second type;   generating drive signals to control a gas flow regulating valve that supplies gas to the burner and to control a rotation speed of a fan configured to take in oxidative air;   sending the drive signals to the gas flow regulating valve and to a motor connected to the fan; and   receiving at least one temperature signal representing a temperature inside a combustion cell of the burner;   wherein the processor is configured to confirm that the burner is on based on the flame signal and on the temperature signal.   
     
     
         15 . A device for controlling a fuel-oxidizer mixture for a premix gas burner, comprising:
 an intake duct which defines a section for the admission of a fluid into the duct and includes an inlet for receiving the oxidizer, a mixing zone for receiving the fuel and allowing it to be mixed with the oxidizer, and an outlet for delivering the mixture to the burner;   an injection duct connected to the intake duct in the mixing zone to supply the fuel;   a gas regulating valve located along the injection duct;   a fan configured and adapted to rotate at a variable rotation speed and located in the intake duct to generate therein a flow of oxidizer in a direction of inflow oriented from the inlet to the delivery outlet;   a first flame sensor configured to detect a first flame signal representing the presence of a flame deriving from the combustion of a fuel of a first type inside a combustion cell of the burner;   a control unit including a processor programmed to receive a flame signal and to generate drive signals representing a position of the gas regulating valve and the rotation speed of the suction fan based on the flame signal; and   a second flame sensor configured to detect a second flame signal representing the presence of a flame deriving from the combustion of a fuel of a second type inside a combustion cell of the burner;   wherein the processor is programmed to receive fuel data representing the fact that the fuel is of the first type or of the second type; and   wherein the flame signal is defined by the signal of the first flame sensor and/or of the second flame sensor depending on the fuel data.   
     
     
         16 . The device according to  claim 15 , wherein the processor is configured to derive the fuel data, representing a quantity of fuel of the first type and/or a quantity of fuel of the second type, based on the first flame signal and on the second flame signal. 
     
     
         17 . The device according to  claim 16 , wherein the processor is programmed for:
 accessing a memory unit containing first regulation data and second regulation data, different from the first regulation data;   selecting one between the first regulation data and the second regulation data, based on the fuel data; and   generating the drive signals based on the regulation data selected.   
     
     
         18 . The device according to  claim 15 , comprising a user interface connected to the control unit and configured to allow a user to enter the fuel data manually.