Safety System for a Liquid Fuel Tank

Abstract

A fuel tank system includes a fill tube in communication with a tank; and a sealing device in the fill tube. A vent valve is mounted on the tank, the vent valve being open during a filling operation of the tank with a fuel and during periods of normal use of the tank. A vent pipe has a first end connected to the tank and with a second end in communication with the fill tube. The vent pipe is configured to allow vapors to escape from the tank without creating a substantial over pressure inside the tank so that the filling operation takes place without pressure in the tank, and the vent valve is open during the filling operation without pressure in the tank.

1 . A fuel tank system comprising: 
 a fill tube in communication with a tank;    a sealing device in said fill tube;    a vent valve mounted on said tank, said vent valve being open during a filling operation of said tank with a fuel and during periods of normal use of said tank; and    a vent pipe with a first end connected to said tank and with a second end in communication with said fill tube,    wherein said vent pipe is configured to allow vapors to escape from said tank without creating a substantial over pressure inside said tank so that said filling operation takes place without pressure in said tank, and said vent valve being open during said filling operation without pressure in said tank.    
   
   
       2 . The system according to  claim 1 , further comprising a canister in communication with said vent valve.  
   
   
       3 . The system according to  claim 2 , wherein said canister comprises a material that absorbs fuel vapors.  
   
   
       4 . The system according to  claim 1 , wherein said fill tube is in communication with a lower half portion of said tank.  
   
   
       5 . The system according to  claim 1 , wherein said fill tube defines an upper orifice configured to receive a nozzle spout during said filling operation.  
   
   
       6 . The system according to  claim 1 , wherein the sealing device is made of a flexible elastomer material.  
   
   
       7 . The system according to  claim 5 , wherein said sealing device comprises at least one lip configured to seal said fill tube from an outside environment during said filling operation.  
   
   
       8 . The system according to  claim 7 , wherein said at least one lip is flexible.  
   
   
       9 . The system according to  claim 7 , wherein said at least one lip is circular.  
   
   
       10 . The system according to  claim 7 , wherein said sealing device comprises an obturator located between said tank and said at least one lip, wherein said obturator is configured to open under pressure when an end of said nozzle spout comes into contact with said obturator.  
   
   
       11 . The system according to  claim 7 , wherein said sealing device comprises a plurality of flexible lips.  
   
   
       12 . The system according to  claim 1 , wherein said vent valve is a float valve.  
   
   
       13 . The system according to  claim 12 , wherein said float valve closes when said fuel reaches a predetermined level in said tank.  
   
   
       14 . The system according to  claim 1 , wherein said vent valve is closed when said tank is inclined beyond a predetermined limit.  
   
   
       15 . The system according to  claim 14 , wherein said vent valve is closed when said tank is upside down.  
   
   
       16 . The system according to  claim 15 , wherein said vent valve is closed during a transient movement of the fuel, the magnitude of said movement exceeding a predetermined value.  
   
   
       17 . The system according to  claim 1 , wherein said second end of said vent pipe is in communication with the fill tube at a location between said tank and said sealing device.  
   
   
       18 . The system according to  claim 1 , wherein said fill tube comprises a guide member configured to guide a nozzle spout through said sealing device.  
   
   
       19 . The system according to  claim 1 , wherein said vent valve consists essentially of one moving device configured to open and close said vent valve.  
   
   
       20 . The system according to  claim 1 , wherein said vent valve consists essentially of one float valve.  
   
   
       21 . The system according to  claim 12 , wherein said float valve consists essentially of one sliding device configured to follow a level of fuel in said tank as soon as said level reaches a bottom rest position of said one sliding device.