Burner control systems and methods of operating a burner

Abstract

Burner control systems and methods of operating a burner are for a large boiler such as might be used in hospitals, hotels, offices or other large commercial or domestic premises.

1 . A burner control system for controlling operation of a burner, the system comprising a regulator system for controlling the proportion of air to fuel fed to the burner, wherein the control system is arranged to receive an input signal relating to measurement of at least one ambient variable selected from the group consisting of the ambient air pressure and the ambient air temperature, and the signal is used to trim the proportion of air to fuel fed to the burner. 
     
     
         2 . A burner control system according to  claim 1 , wherein the control system is arranged to provide an output signal for adjusting an air valve to alter the airflow to the burner by trimming the setting of the air valve according to the ambient air pressure and/or the ambient air temperature. 
     
     
         3 . A burner control system according to  claim 1 , further including a system for analysing exhaust gases emitted by the burner and trimming the proportion of air to fuel according to the analysis. 
     
     
         4 . A burner control system according to  claim 1 , wherein the system further includes a store for storing pairs of values of air and fuel valve settings for varying firing rates of the burner. 
     
     
         5 . A burner control system according to  claim 4 , wherein for each pair of values of air and fuel valve settings a respective value of air pressure of the airflow to the burner is arranged to be stored. 
     
     
         6 . A burner control system according to  claim 4 , wherein for each pair of values of air and fuel valve settings a respective value of fuel pressure of the fuel flow to the burner is arranged to be stored. 
     
     
         7 . A burner control system for controlling operation of a burner, wherein pairs of values of air and fuel valve settings are stored for varying firing rates of the burner, and in which for each pair of values of air and fuel valve settings at least one respective value selected from the group consisting of the respective value of the air pressure of the airflow to the burner and the respective value of the fuel pressure of the fuel flow to the burner, is arranged to be stored. 
     
     
         8 . A burner control system according to  claim 7 , wherein the control system is arranged to monitor the air pressure and/or the fuel pressure at a given firing rate and compare the monitored air pressure and/or fuel pressure with the stored air and/or fuel pressure value corresponding to that firing rate, or to an interpolated value if the firing rate is between those to which stored air and fuel valve settings relate, and to emit an output signal for shutting down the burner in the event that the compared values differ by more than a predetermined amount. 
     
     
         9 . A burner control system according to  claim 7 , further including a system for analysing exhaust gases emitted by the burner and trimming the proportion of air to fuel according to the analysis. 
     
     
         10 . A burner control system according to  claim 1 , further including a burner which is arranged to be controlled by the control system, a fuel valve for adjusting the flow of fuel to the burner and an air valve for adjusting the flow of air to the burner. 
     
     
         11 . A burner control system according to  claim 10 , further including a sensor for sensing ambient air pressure and/or a sensor for sensing ambient air temperature. 
     
     
         12 . A burner control system according to  claim 10 , further including a sensor for sensing the pressure in the airflow to the burner and/or a sensor for sensing the pressure in the fuel flow to the burner. 
     
     
         13 . A method of operating a burner in which a regulator system controls the proportion of air to fuel fed to the burner, comprising measuring at least one ambient variable selected from the group consisting of the ambient air pressure and the ambient air temperature, and the measurement is used to trim the proportion of air to fuel fed to the burner. 
     
     
         14 . A method according to  claim 13 , wherein an air valve is adjusted to alter the airflow to the burner and the setting of the air valve is trimmed according to at least one ambient variable selected from the group consisting of the ambient air pressure and the ambient air temperature. 
     
     
         15 . A method according to  claim 13 , in which exhaust gases emitted by the burner are analysed and the proportion of air to fuel trimmed according to the analysis. 
     
     
         16 . A method of operating a burner, comprising: controlling flows of air and fuel are controlled by air and fuel valves respectively; storing pairs of values of air and fuel valve settings are stored for varying firing rates of the burner; and storing for each pair of values of air and fuel valve settings at least one respective value selected from the group consisting of a respective value of air pressure of the airflow and a respective value of fuel pressure of the fuel flow. 
     
     
         17 . A burner control system according to  claim 7 , further including a burner arranged to be controlled by the control system, a fuel valve for adjusting the flow of fuel to the burner and an air valve for adjusting the flow of air to the burner.