relief (by-pass)
valve seal cap
o-ring
washer
spring
relief (by-pass) valve
relief (by-pass) valve cap
gasket
adjusting screw
hex nut
Figure 11.2: Relief Valve
11.3 Float and Valve Seat Assembly
The cavity formed by the inside of the body of the pumping unit is the air separator. Product,
with some trapped air and vapor, is pumped into the air separator chamber. The air rises to the
top and is pushed out through a tube that is connected to the bottom face plate on the dispenser.
The float and valve seat assembly is located inside the air separator chamber.
The function of the float and valve assembly is to shut off the flow from the air separator chamber
to the suction side of the pump when there is no product in the air separator chamber. When
product is in the air separator chamber it causes the float to rise, opens the valve seat, and allows
product to return to the suction side of the pump.
11.4 Air Separation
The air separation of the pumping unit is accomplished in the following manner: product is directed
into one end of a cylindrical chamber in the pumping unit. The product then starts to swirl along
the chamber and discharges out the other end. Through the centrifugal force on the product, air
being lighter than gasoline, the air goes to the center of the swirling product. The air is collected
by a tube at the end of the cylindrical chamber and then discharged into the air separation
chamber through a small hole. Both product and air exit the small hole. The product is returned
to the suction side of the pump when the product in the chamber becomes high enough to lift
the float assembly.
11.5 Testing the Suction Pumping System
A vacuum gauge and a pressure gauge are required to properly test and accurately diagnose
problems with the suction pump.
186 WM048523 Rev 08 01/2019
11 Suction Pumps
To Next Page
Loading...
