Device for Controlling the Delivery of a Combustible Gas to a Burner Apparatus

Abstract

A device for controlling the delivery of a combustible gas to a burner apparatus is provided. The device includes a main pipe for delivery of the gas in which are disposed first and second servovalves in cascade with each other, with respect to the direction of flow of the gas. The servovalves include respective valve seats associated with corresponding shut-off means with diaphragm control for the opening of the seats. The first and second servovalves include respective first and second control solenoid valves with electromagnetic operating means to control the opening/closing of the corresponding servovalve. The solenoid valves are arranged to act to open/close the pipes of respective servo-assisted control circuits, so as to control indirectly, by way of the diaphragm control, the respective shut-off means of the corresponding servovalve the pipes of the control circuit placing the main pipe in fluid communication with respective control chambers of the servovalves.

1 . A device for controlling the delivery of a combustible gas to a burner apparatus, comprising a main pipe for delivery of the gas in which are disposed a first and a second servovalve, respectively in cascade with each other, with respect to the direction of flow of the gas, said servovalves including respective valve seats associated with corresponding shut-off means with diaphragm control for the opening of said seats in opposition to respective resilient return means,
 said first and second servovalves comprising a respective first and second control solenoid valve with electromagnetic operating means for controlling the opening/closure of the corresponding servovalve, said solenoid valves being arranged to act for opening/closing pipes of respective servo-assisted control circuits, so as to control indirectly, by way of the diaphragm control, the respective shut-off means of the corresponding servovalve, the pipes of the control circuit placing the main pipe in fluid communication with respective control chambers, of the servovalves, one side of the diaphragms of said diaphragm controls being subjected to pressure existing in the respective control chamber, wherein intake pipes of the respective control circuits, capable of picking up a pressure signal to be transmitted to the corresponding control chamber, are both respectively connected, in fluid communication, with the main pipe, upstream of the first servovalve.   
   
   
       2 . A device according to  claim 1 , wherein the control circuit of the first servovalve comprises a first discharge pipe of the corresponding first control chamber which is connected, in fluid communication, with a section of the main pipe lying between the valve seats of the respective servovalves. 
   
   
       3 . A device according to  claim 1 , wherein from the portion of main pipe extending between the valve seats of the respective servovalves there extends a pilot pipe for supplying gas to a pilot burner. 
   
   
       4 . A device according to,  claim 1  wherein said solenoid valves are disposed in cascade with each other, along a first common portion of intake pipe connected at one end thereof with a section of the main pipe upstream of the first servovalve. 
   
   
       5 . A device according to  claim 4 , wherein a second portion of the intake pipe, capable of connecting the first control chamber with the main pipe, extends between a section of said first common portion of intake pipe, lying between said control solenoid valves, and the first control chamber. 
   
   
       6 . A device according to  claim 1 , wherein the control circuits of the first and second servovalves comprise a respective first and second discharge pipe of the corresponding first and second control chamber, which are connected, in fluid communication, with a section of the main pipe downstream of the second servovalve. 
   
   
       7 . A device according to  claim 6 , wherein said solenoid valves are disposed in cascade with each other, along a first common portion of intake pipe connected at one end thereof with a section of the main pipe upstream of the first servovalve. 
   
   
       8 . A device according to  claim 7 , wherein from said first common portion of intake pipe there extends, at a section lying between said control solenoid valves, a pilot pipe for supplying gas to a pilot burner. 
   
   
       9 . A device according to  claim 1 , comprising a pressure regulator with diaphragm control disposed in the portion of pipe of the control circuit of the second servovalve, which extends between the corresponding control chamber of said second servovalve and a section of the main pipe downstream of the second servovalve. 
   
   
       10 . A device according to  claim 9 , wherein said pressure regulator comprises actuating means operationally connected to the shut-off means of said regulator for controlling in modulation the displacement of said shut-off means and consequently modulating the pressure controlled by said regulator. 
   
   
       11 . A device according to  claim 10 , wherein an electromagnetic operating means is provided for controlling said actuating means. 
   
   
       12 . A device according to  claim 11 , wherein a reversible electric motor, of the stepping type, is provided for controlling the displacement of the shut-off means of said diaphragm pressure regulator. 
   
   
       13 . A device according to  claim 2 , wherein from the portion of main pipe extending between the valve seats of the respective servovalves there extends a pilot pipe for supplying gas to a pilot burner. 
   
   
       14 . A device according to  claim 2 , wherein said solenoid valves are disposed in cascade with each other, along a first common portion of intake pipe connected at one end thereof with a section of the main pipe upstream of the first servovalve. 
   
   
       15 . A device according to  claim 3 , wherein said solenoid valves are disposed in cascade with each other, along a first common portion of intake pipe connected at one end thereof with a section of the main pipe upstream of the first servovalve. 
   
   
       16 . A device according to  claim 13 , wherein said solenoid valves are disposed in cascade with each other, along a first common portion of intake pipe connected at one end thereof with a section of the main pipe upstream of the first servovalve. 
   
   
       17 . A device according to  claim 2 , comprising a pressure regulator with diaphragm control disposed in the portion of pipe of the control circuit of the second servovalve, which extends between the corresponding control chamber of said second servovalve and a section of the main pipe downstream of the second servovalve. 
   
   
       18 . A device according to  claim 3 , comprising a pressure regulator with diaphragm control disposed in the portion of pipe of the control circuit of the second servovalve, which extends between the corresponding control chamber of said second servovalve and a section of the main pipe downstream of the second servovalve. 
   
   
       19 . A device according to  claim 4 , comprising a pressure regulator with diaphragm control disposed in the portion of pipe of the control circuit of the second servovalve, which extends between the corresponding control chamber of said second servovalve and a section of the main pipe downstream of the second servovalve. 
   
   
       20 . A device according to  claim 5 , comprising a pressure regulator with diaphragm control disposed in the portion of pipe of the control circuit of the second servovalve, which extends between the corresponding control chamber of said second servovalve and a section of the main pipe downstream of the second servovalve.