Stagnant Fuel Thermal Insulation System

Abstract

A method and apparatus comprising a structure. The structure is configured to be placed around a fluid line in a container that is configured to hold a fluid. The structure is further configured to reduce a flow of the fluid within a volume of the structure such that the fluid in the volume insulates the fluid line.

1 . An apparatus comprising:
 a structure configured to be placed around a fluid line in a container that is configured to hold a fluid, wherein the structure is configured to reduce a flow of the fluid within a volume of the structure such that the fluid in the volume insulates the fluid line.   
     
     
         2 . The apparatus of  claim 1 , wherein the structure is configured to retain the fluid within the volume of the structure when the structure is at least partially immersed in the fluid in the container and wherein retained fluid within the volume of the structure flows out of the volume of the structure as a level of the fluid in the container lowers in a manner that results in less of the volume of the structure being filled with the fluid. 
     
     
         3 . The apparatus of  claim 1  further comprising:
 a retaining system configured to hold the structure around the fluid line. 
 
     
     
         4 . The apparatus of  claim 3 , wherein the retaining system comprises:
 a cover configured to hold the structure around the fluid line.   
     
     
         5 . The apparatus of  claim 3 , wherein the retaining system comprises:
 a number of clamps configured to reduce movement of the structure along the fluid line.   
     
     
         6 . The apparatus of  claim 1 , wherein the flow of the fluid that is reduced is caused by a convective current through the fluid in the container. 
     
     
         7 . The apparatus of  claim 1 , wherein the structure comprises:
 a porous material defining the volume, wherein the porous material is configured to reduce the flow of the fluid.   
     
     
         8 . The apparatus of  claim 7 , wherein the porous material takes a form of a foam. 
     
     
         9 . The apparatus of  claim 8 , wherein the foam has about 45 cells per inch and a porosity of about 93 percent. 
     
     
         10 . The apparatus of  claim 8 , wherein the foam has a thickness of about 0.2 inches. 
     
     
         11 . The apparatus of  claim 1 , wherein the structure comprises:
 a tube configured to be placed around the fluid line.   
     
     
         12 . The apparatus of  claim 1 , wherein the fluid line is configured to carry a hydraulic fluid, the container is a fuel tank, and the fluid in the container is fuel. 
     
     
         13 . The apparatus of  claim 1 , wherein the structure is configured to maintain a desired temperature for the fluid line when the fluid in the container has a temperature of about minus 40 degrees Fahrenheit. 
     
     
         14 . The apparatus of  claim 1  further comprising:
 the container; and 
 the fluid line. 
 
     
     
         15 . The apparatus of  claim 1 , wherein the fluid line and the container are located in a platform selected from one of a mobile platform, a stationary platform, a land-based structure, an aquatic-based structure, a space-based structure, an aircraft, an unmanned aerial vehicle, a helicopter, a submarine, a bus, a personnel carrier, a tank, a train, an automobile, a spacecraft, a space station, a satellite, a surface ship, a power plant, a dam, a manufacturing facility, a piece of equipment, and a building. 
     
     
         16 . A fluid line insulation system for an aircraft comprising:
 a structure configured to be placed around a fluid line in a fuel tank of the aircraft that is configured to hold fuel, wherein the structure is configured to reduce a flow of the fuel in a volume within the structure such that a transfer of heat between a fluid in the fluid line and the fuel in the fuel tank outside of the structure is reduced.   
     
     
         17 . The fluid line insulation system of  claim 16 , wherein the structure is a foam and further comprising:
 a retaining system configured to hold the foam around the fluid line.   
     
     
         18 . A method for insulating a fluid line, the method comprising:
 positioning a structure around the fluid line, wherein the structure is configured to retain a fluid within a volume of the structure; and   reducing a flow of the fluid within the volume of the structure such that the fluid within the volume of the structure insulates the fluid line.   
     
     
         19 . The method of  claim 18 , wherein the structure and the fluid line are located in a fuel tank and wherein the structure is configured to contact the fluid line when positioned around the fluid line. 
     
     
         20 . The method of  claim 19 , wherein the fuel tank is in an aircraft.