Now for a closer look at some of the systems and components mentioned earlier in the program. Where model year design differences exist they will also be pointed out.
Letโs begin with the component that supplies and pressurizes the fuel: The Transfer Pump.
The positive displacement vane type transfer pump consists of a stationary liner and four spring loaded blades. Since the inside diameter of the liner is eccentric to the rotor axis, inlet and discharge cavities are formed by the blades as they rotate. (Figure 4-46).
As a blade passes over the inlet slot it enlarges the inlet volume, creating suction. The cavity between this and the second blade fills with fuel until the second blade passes the end of the inlet slot. (Figure 4-47). This volume of fuel is carried around until the leading blade uncovers the end of the discharge slot as shown in the next illustration.
As the leading blade continues to pass over the discharge slot it is followed by the second blade which pushes the captive volume of fuel ahead of it. Since the blades are moving into a decreasing volume in the liner, the captive fuel is squeezed out through the discharge slot by the following blade as shown in Figure 4-48.
This sequence takes place four times every revolution of the rotor, producing a continuous discharge.
