Nitrogen Blanketing System

Abstract

A nitrogen blanket system for small fuel tanks is disclosed that includes tank empty-space pressure control for sealed tanks that can hold pressure. The system includes a fuel tank storing some volume of fuel, such as diesel fuel. The remaining empty volume is filled with nitrogen by the disclosed system. The nitrogen blankets the liquid fuel and fills the remaining space in the fuel tank to prevent the accumulation of moisture and thereby prevent corrosion within the fuel tank.

What is claimed is: 
     
         1 . A nitrogen blanketing system for a fuel tank, the system comprising:
 a nitrogen generator;   a pressure-sensing switch in fluid communication with the nitrogen generator;   a conduit for providing a fluid path between the pressure-sensing switch and the fuel tank; and   a differential switch in fluid communication with the fuel tank via the conduit;   wherein the pressure-sensing switch is configured to close to prevent nitrogen from flowing from the nitrogen generator to the fuel tank if atmospheric pressure in the fuel tank is above a first predetermined level, and configured to open to allow nitrogen to flow from the nitrogen generator to the fuel tank if atmospheric pressure in the fuel tank is below the first predetermined level; and   wherein the differential switch is configured to open to allow nitrogen to escape from the fuel tank via the conduit if atmospheric pressure in the fuel tank is above a second predetermined level, and configured to close to prevent nitrogen from escaping from the fuel tank via the conduit if atmospheric pressure in the fuel tank is below the second predetermined level.   
     
     
         2 . The system of  claim 1 , further comprising:
 a dispenser in fluid communication with the tank via the conduit.   
     
     
         3 . The system of  claim 2 , wherein the dispenser is configured to dispense a volatile corrosion inhibitor into the tank while nitrogen is flowing in the conduit towards the tank. 
     
     
         4 . The system of  claim 1 , further comprising:
 a pressure vacuum valve in fluid communication with the tank via the conduit while the differential switch is open.   
     
     
         5 . The system of  claim 1 , further comprising:
 a buffer tank in fluid communication with the nitrogen generator and the pressure-sensing switch.   
     
     
         6 . A system, comprising:
 a nitrogen blanketing system for a fuel tank, the system comprising:
 a nitrogen generator; 
 a pressure-sensing switch in fluid communication with the nitrogen generator; 
 a conduit for providing a fluid path between the pressure-sensing switch and the fuel tank; and 
 a differential switch in fluid communication with the fuel tank via the conduit; 
 wherein the pressure-sensing switch is configured to close to prevent nitrogen from flowing from the nitrogen generator to the fuel tank if atmospheric pressure in the fuel tank is above a first predetermined level, and configured to open to allow nitrogen to flow from the nitrogen generator to the fuel tank if atmospheric pressure in the fuel tank is below the first predetermined level; and 
 wherein the differential switch is configured to open to allow nitrogen to escape from the fuel tank via the conduit if atmospheric pressure in the fuel tank is above a second predetermined level, and configured to close to prevent nitrogen from escaping from the fuel tank via the conduit if atmospheric pressure in the fuel tank is below the second predetermined level; and 
   a nitrogen vending station comprising:
 an air hose in fluid communication with the nitrogen generator; and 
 a user-operable valve for controlling the flow of nitrogen from the air hose. 
   
     
     
         7 . The system of  claim 6 , wherein the nitrogen vending station further comprises:
 a payment system configured to prohibit nitrogen from flowing from the nitrogen generator through the air hose unless a payment has been made via the payment system.   
     
     
         8 . The system of  claim 7 , further comprising:
 an override switch to override the payment system and allow nitrogen to flow from the nitrogen generator through the air hose without a payment having first been made via the payment system.   
     
     
         9 . A system, comprising:
 a fuel tank configured to store liquid fuel;   a nitrogen generator;   a pressure-sensing switch in fluid communication with the nitrogen generator;   a conduit for providing a fluid path between the pressure-sensing switch and the fuel tank; and   a differential switch in fluid communication with the fuel tank via the conduit;   wherein the conduit extends along the bottom of the fuel tank and includes a plurality of apertures for dispensing nitrogen from the nitrogen generator such that the nitrogen is dispensed into liquid fuel if liquid fuel is present in the fuel tank.   
     
     
         10 . The system of  claim 9 , wherein the pressure-sensing switch is configured to close to prevent nitrogen from flowing from the nitrogen generator to the fuel tank if atmospheric pressure in the fuel tank is above a first predetermined level, and configured to open to allow nitrogen to flow from the nitrogen generator to the fuel tank if atmospheric pressure in the fuel tank is below the first predetermined level. 
     
     
         11 . The system of  claim 9 , wherein the differential switch is configured to open to allow nitrogen to escape from the fuel tank via the conduit if atmospheric pressure in the fuel tank is above a second predetermined level, and configured to close to prevent nitrogen from escaping from the fuel tank via the conduit if atmospheric pressure in the fuel tank is below the second predetermined level. 
     
     
         12 . The system of  claim 11 , further comprising:
 a pressure vacuum valve in fluid communication with the tank via the conduit while the differential switch is open.   
     
     
         13 . The system of  claim 9 , further comprising:
 a buffer tank in fluid communication with the nitrogen generator and the pressure-sensing switch.   
     
     
         14 . The system of  claim 9 , further comprising:
 a dispenser in fluid communication with the tank via the conduit.   
     
     
         15 . The system of  claim 14 , wherein the dispenser is configured to dispense a volatile corrosion inhibitor into the tank while nitrogen is flowing in the conduit towards the tank. 
     
     
         16 . The system of  claim 9 , further comprising:
 an agitator for agitating liquid fuel stored in the fuel tank while nitrogen is flowing from the conduit into the fuel tank.