Method and Controller for Operating a Gas Burner Appliance

Abstract

Method for operating a gas burner appliance ( 10 ), the gas burner appliance ( 10 ) comprising: a combustion chamber ( 11 ), a mixing device ( 23 ), a fan ( 14 ), a gas safety valve unit ( 19 ) assigned to the gas duct ( 16 ) having a first gas safety valve ( 19 a ) and a second gas safety valve ( 19 b ) positioned downstream of the first gas safety valve ( 19 a ), a gas flow modulator ( 18 ) assigned to the gas duct ( 16 ), and an electrical or electronic absolute pressure sensor ( 21 ) assigned to the gas duct ( 16 ) positioned downstream of the first gas safety valve ( 19 a ). The gas burner appliance ( 10 ) is operated to compensate for a fluctuating gas inlet pressure of the gas burner appliance by executing the following steps: Measure a first absolute pressure by the absolute pressure sensor ( 21 ) when at least the first gas safety valve ( 19 a ) of the gas safety valve unit ( 19 ) is closed. Measure a second absolute pressure by the absolute pressure sensor ( 21 ) when the gas safety valve unit ( 19 ) is opened. Determine a pressure difference between the first absolute pressure or a pressure depending on the first absolute pressure and the second absolute pressure or a pressure depending on the second absolute pressure. Operate the gas flow modulator ( 18 ) dependent from said pressure difference.

1 . A method for operating a gas burner appliance,
 the gas burner appliance comprising:   a combustion chamber being configured to combust a defined gas/air mixture,   a mixing device being configured to provide said gas/air mixture by mixing an airflow provided by an air duct with a gas flow provided by a gas duct,   a fan being configured provide the air flow or the flow of the gas/air mixture,   a gas safety valve unit assigned to the gas duct being configured to open or close the gas duct,
 the gas safety valve unit having a first gas safety valve and a second gas safety valve positioned downstream of the first gas safety valve, 
   a gas flow modulator assigned to the gas duct being configured to keep a mixing ratio of gas and air within the gas/air mixture at a defined value,   an electrical or electronic absolute pressure sensor assigned to the gas duct positioned downstream of the first gas safety valve,
 wherein the gas burner appliance is operated to compensate for a fluctuating gas inlet pressure of the gas burner appliance by executing the following steps: 
 measure a first absolute pressure by the absolute pressure sensor when at least the first gas safety valve of the gas safety valve unit is closed, 
 measure a second absolute pressure by the absolute pressure sensor when the gas safety valve unit is opened, determine a pressure difference between the first absolute pressure or a pressure depending on the first absolute pressure and the second absolute pressure or a pressure depending on the second absolute pressure, 
 operate the gas flow modulator dependent from said pressure difference. 
   
     
     
         2 . The method of  claim 1 , wherein
 the first absolute pressure is measured by the absolute pressure sensor when at least the first gas safety valve of the gas safety valve unit is closed and when the fan is stopped.   
     
     
         3 . The method of  claim 1 , wherein
 the first absolute pressure is measured by the absolute pressure sensor when at least the first gas safety valve of the gas safety valve unit is closed and when the fan is running, wherein the pressure depending on the first absolute pressure is determined from the measured first absolute pressure and from a fan speed.   
     
     
         4 . The method of  claim 3 , wherein
 the pressure depending on the first absolute pressure is determined from the measured first absolute pressure and from the fan speed on basis of a first characteristic curve.   
     
     
         5 . The method of  claim 1 , wherein
 the second absolute pressure is measured by the absolute pressure sensor when the gas safety valve unit is opened and when the fan is running.   
     
     
         6 . The method of  claim 1 , wherein
 the pressure difference is determined between the first absolute pressure or the pressure depending on the first absolute pressure and the second absolute pressure.   
     
     
         7 . The method of  claim 6 , wherein
 the pressure difference is adapted into an adapted pressure difference as a function of a fan speed,   the gas flow modulator is operated on basis of said adapted pressure difference to compensate for a fluctuating gas inlet pressure of the gas burner appliance.   
     
     
         8 . The method of  claim 1 , wherein
 the pressure difference is adapted into said adapted pressure difference on basis of a second characteristic curve.   
     
     
         9 . The method of  claim 1 , wherein
 for a start-up of the gas burner appliance the following steps are executed;
 measure the first absolute pressure when at least the first gas safety valve of the gas safety valve unit is closed, 
 then open the gas safety valve unit, run the fan at a defined fan speed, activate an ignition device and measure continuously or at a defined sampling rate the second absolute pressure while increasing the opening position of the gas flow modulator, 
 determine continuously or at the defined sampling rate the pressure difference, 
 adjust continuously or at the defined sampling rate the opening position of the gas flow modulator dependent from said pressure difference. 
   
     
     
         10 . The method of  claim 1 , wherein
 after a start-up of the gas burner appliance while a gas-air mixture is combusted the following steps are executed:
 adapt the first absolute pressure to compensate for fluctuating weather conditions, 
 measure continuously or at a defined sampling rate the second absolute pressure, 
 determine continuously or at the defined sampling rate the pressure difference, 
 adjust continuously or at the defined sampling rate the opening position of the gas flow modulator dependent from said pressure difference. 
   
     
     
         11 . The method of  claim 10 , wherein
 the first absolute pressure is adapted to compensate for fluctuating weather conditions on basis of an absolute pressure measured by an additional absolute pressure sensor not being assigned the gas duct.   
     
     
         12 . The method of  claim 10 , wherein
 the first absolute pressure is adapted to compensate for fluctuating weather conditions on basis of an absolute pressure received over the Internet.   
     
     
         13 . The method of  claim 10 , wherein
 the first absolute pressure is adapted to compensate for fluctuating weather conditions by executing the following steps:
 during the start-up of the gas burner appliance measure the first and second absolute pressure and determine a first difference from the same and use said difference as offset value, 
 after a start-up of the gas burner appliance determine continuously or at the defined sampling rate a second difference between the second absolute pressure and the offset value, filter said second difference by limiting the temporal gradient of said second difference to a maximum value and use the filtered second difference as adapted first absolute pressure. 
   
     
     
         14 . The method of  claim 1 , wherein
 after a start-up of the gas burner appliance while a gas-air mixture is combusted the following steps are executed:
 measure continuously or at a defined sampling rate the second absolute pressure, 
 determine continuously or at the defined sampling rate the pressure difference, 
 adjust continuously or at the defined sampling rate the opening position of the gas flow modulator dependent from said pressure difference, namely dependent from the temporal gradient of said pressure difference. 
   
     
     
         15 . A controller of a gas burner appliance for operating the gas burner appliance,
 wherein the controller is configured to compensate for a fluctuating gas inlet pressure of the gas burner appliance by executing the following steps:
 measure a first absolute pressure by the absolute pressure sensor when at least a first gas safety valve of a gas safety valve unit is closed, 
 measure a second absolute pressure by the absolute pressure sensor when the gas safety valve unit is opened, 
 determine a pressure difference between the first absolute pressure or a pressure depending on the first absolute pressure and the second absolute pressure or a pressure depending on the second absolute pressure, 
 operate a gas flow modulator dependent from said pressure difference. 
   
     
     
         16 . The controller of  claim 15 , wherein
 the controller is configured to operate the gas burner appliance according to the method of  claim 1 .   
     
     
         17 . The method of  claim 2 , wherein the second absolute pressure is measured by the absolute pressure sensor when the gas safety valve unit is opened and when the fan is running. 
     
     
         18 . The method of  claim 3 , wherein the second absolute pressure is measured by the absolute pressure sensor when the gas safety valve unit is opened and when the fan is running. 
     
     
         19 . The method of  claim 4 , wherein the second absolute pressure is measured by the absolute pressure sensor when the gas safety valve unit is opened and when the fan is running. 
     
     
         20 . The method of  claim 2 , wherein the pressure difference is determined between the first absolute pressure or the pressure depending on the first absolute pressure and the second absolute pressure.