SECTION III. TECHNICAL PRINCIPLES OF OPERATION
1-12. Technical Principles of Operation.
a. General. The filter/separator is a static device which is installed in a fuel system to remove water and solid
contaminants from the fuel. The filter/separator is normally installed between the fuel system pump and the fuel
dispensing equipment. Thus, fuel is pushed through the filter/separator by pump action.
b. Sinplified Principles of Operation. Fuel enters through the inlet connection and passes through the filter center
tube and passes towards the outside of the element. Upon reaching the exterior of the element the fuel passes through
the layers of plated paper, cotton knit and screen. The water droplets, being heavier than fuel, fall to the bottom of the
tank. As water collects in the tank, the water level rises. Clean fuel floats on top of this water. The point at which the
fuel and water meet is known as the interface. The liquid level gage gives a visual indication of this interface. Manual
controls permit the discharge of the separated water and prevents the flow of fuel out of the filter/separator.