Partially-premixed gas burner appliance

Abstract

Partially-premixed gas burner appliance (10), comprising a combustion chamber (11), a fan (17) and a gas modulator (20). The fan (17) is configured to provide an air flow to the combustion chamber (11) and is assigned to an air inlet port (11A) of the combustion chamber or to an air duct (18) configured to provide the air to the air inlet port. An air flow restriction element (19) is assigned to the air inlet port (11A) or to the air duct (18). The air flow restriction element (19) is configured to provide a pressure drop so that the pressure downstream of the air flow restriction element (19) is lower than the pressure upstream of the same. The gas modulator (20) is configured to provide a gas flow to the combustion chamber (11), wherein a first portion of the air provided by the fan (17) is premixed with the gas flow before the gas is combusted, and wherein a second portion of the air provided by the fan (17) is mixed with the gas while the gas is combusted. The gas modulator (20) is a pneumatic gas control valve, wherein the pneumatic gas control valve has a main gas valve (22), a safety gas valve (23), a servo gas valve (24) and gas outlet pres-sure regulator (25). The gas outlet pressure regulator (25), namely a first chamber (33) of the same in which a pressure is present that influences the nominal-value of the gas outlet pressure of the pneumatic gas control valve, is connected to the air inlet port (11A) or to the air duct (18) upstream of the air flow restriction element (19) such that the gas outlet pressure provided by the pneumatic gas control valve de-pends on the air pressure upstream of the air flow restriction element (19).

1 . A partially-premixed gas burner appliance, comprising:
 a combustion chamber,   a fan configured to provide an air flow to the combustion chamber,
 wherein the fan is assigned to an air inlet port of the combustion chamber or to an air duct configured to provide the air to the air inlet port, 
   an air flow restriction element assigned to the air inlet port of the combustion chamber or to the air duct and configured to provide a pressure drop so that the pressure downstream of the air flow restriction element is lower than the pressure upstream of the air flow restriction element,   a gas modulator being configured to provide a gas flow to the combustion chamber,
 wherein a first portion of the air provided by the fan is premixed with the gas flow before the gas is combusted, 
 wherein a second portion of the air provided by the fan is mixed with the gas while the gas is combusted, 
 wherein the gas modulator is a pneumatic gas control valve having a main gas valve, a safety gas valve, a servo gas valve, and a gas outlet pressure regulator,
 wherein the gas outlet pressure regulator, namely a first chamber of the gas outlet pressure regulator in which a pressure is present that influences the nominal-value of the gas outlet pressure of the pneumatic gas control valve, is connected to the air inlet port or to the air duct upstream of the air flow restriction element such that the gas outlet pressure provided by the pneumatic gas control valve depends on the air pressure provided by the fan upstream of the air flow restriction element. 
 
   
     
     
         2 . The partially-premixed gas burner appliance as claimed in  claim 1 , wherein the first chamber of the gas outlet pressure regulator of the pneumatic gas control valve is connected to the air inlet port of the combustion chamber or to the air duct through a pipe or duct. 
     
     
         3 . The partially-premixed gas burner appliance as claimed in  claim 1 ,
 wherein the gas outlet pressure regulator of the pneumatic gas control valve comprises a diaphragm,   wherein the first chamber of the gas outlet pressure regulator is positioned on a first side of the diaphragm such that the pressure present within the first chamber acts on the first side of the diaphragm,   wherein a second chamber of the gas outlet pressure regulator is positioned on a second side of the diaphragm, wherein the second chamber of the gas outlet pressure regulator is connected to a gas outlet chamber of the pneumatic gas control valve such that the gas outlet pressure present within the second chamber acts on the second side of the diaphragm.   
     
     
         4 . The partially-premixed gas burner appliance as claimed in  claim 3 ,
 wherein the gas outlet pressure regulator comprises a first spring, wherein a spring force provided by the first spring acts on the first side of the diaphragm   wherein the gas outlet pressure regulator comprises a second spring, wherein a spring force provided by the second spring acts on the second side of staid the diaphragm,   wherein the gas outlet pressure regulator comprises a presetting unit being configured to act on the first spring and to adapt the respective spring force acting on the first side of the diaphragm.   
     
     
         5 . The partially-premixed gas burner appliance as claimed in  claim 4 , wherein the presetting unit is configured to adapt the nominal-value of the gas outlet pressure of the pneumatic gas control valve. 
     
     
         6 . The partially-premixed gas burner appliance as claimed in  claim 3 ,
 wherein the main gas valve of the pneumatic gas control valve comprises a diaphragm and a springer,
 wherein the gas outlet pressure provided by the pneumatic gas control valve and a spring force provided by the spring of the main gas valve act on a first side of the diaphragm of the main gas valve to close the main gas valve, 
 wherein a servo gas chamber is positioned on a second side of the diaphragm of the main gas valve, wherein a servo gas pressure being present within the servo gas chamber acts on the second side of the diaphragm of the main gas valve to open the main gas valve, 
 wherein the servo gas chamber is connected to the servo gas valve of the pneumatic gas control valve and to the gas out-let pressure regulator of the pneumatic gas control valve. 
   
     
     
         7 . The partially-premixed gas burner appliance as claimed in  claim 6 , wherein the servo gas chamber is connected to the gas outlet pressure regulator through a pressure relief valve integrated in the diaphragm of the gas outlet pressure regulator. 
     
     
         8 . The partially-premixed gas burner appliance as claimed in  claim 1 ,
 wherein a gas burner rod having at least two segments is positioned within the combustion chamber,   wherein the combustion chamber comprises for each segment of the gas burner rod at least one individual gas inlet port,   wherein the pneumatic gas control valve provides a gas flow to each of the individual gas inlet ports of the combustion chamber.   
     
     
         9 . The partially-premixed gas burner appliance as claimed in  claim 8 , wherein a shut off valve is assigned to at least one of the individual gas inlet ports to selectively open or close the respective gas inlet port thereby selectively operating the respective segment of the gas burner rod. 
     
     
         10 . The partially-premixed gas burner appliance as claimed in  claim 1 , wherein the pneumatic gas control valve is configured to be used in a fully-premixed gas burner appliance. 
     
     
         11 . The partially-premixed gas burner appliance as claimed in claim, wherein the gas outlet pressure regulator of the pneumatic gas control valve comprises a diaphragm,
 the first chamber of the gas outlet pressure regulator is positioned on a first side of the diaphragm such that the pressure present within the first chamber acts on the first side of the diaphragm,   a second chamber of the gas outlet pressure regulator is positioned on a second side of the diaphragm, wherein the second chamber of the gas outlet pressure regulator is connected to a gas outlet chamber of the pneumatic gas control valve such that the gas outlet pressure present within the second chamber acts on the second side of the diaphragm.   
     
     
         12 . The partially-premixed gas burner appliance as claimed in  claim 4 , wherein
 the main gas valve of the pneumatic gas control valve comprises a diaphragm and a spring,
 wherein the gas outlet pressure provided by the pneumatic gas control valve and a spring force provided by the spring of the main gas valve act on a first side of the diaphragm of the main gas valve to close the main gas valve, 
 wherein a servo gas chamber is positioned on a second side of the diaphragm of the main gas valve, wherein a servo gas pressure being present within the servo gas chamber acts on the second side of the diaphragm of the main gas valve to open the main gas valve, 
 wherein the servo gas chamber is connected to the servo gas valve of the pneumatic gas control valve and to the gas out-let pressure regulator of the pneumatic gas control valve. 
   
     
     
         13 . The partially-premixed gas burner appliance as claimed in  claim 5 , wherein
 the main gas valve of the pneumatic gas control valve comprises a diaphragm and a spring,
 wherein the gas outlet pressure provided by the pneumatic gas control valve and a spring force provided by the spring of the main gas valve act on a first side of the diaphragm of the main gas valve to close the main gas valve, 
 wherein a servo gas chamber is positioned on a second side of the diaphragm of the main gas valve, wherein a servo gas pressure being present within the servo gas chamber acts on the second side of the diaphragm of the main gas valve to open the main gas valve, 
 wherein the servo gas chamber is connected to the servo gas valve of the pneumatic gas control valve and to the gas out-let pressure regulator of the pneumatic gas control valve.