Gear Pump

Simple Gear Pump

There are several variations of 

gear pumps. The simple gear

pump shown in Figure 14

consists of two spur gears

meshing together and revolving in

opposite directions within a

casing. Only a few thousandths

of an inch clearance exists

between the case and the gear

faces and teeth extremities

Simple Gear Pump

. Any

liquid that fills the space bounded

by two successive gear teeth and

the case must follow along with

the teeth as they revolve. When

the gear teeth mesh with the teeth

of the other gear, the space

between the teeth is reduced, and

the entrapped liquid is forced out

the pump discharge pipe. As the

gears revolve and the teeth disengage, the space again opens on the suction side of the

pump, trapping new quantities of liquid and carrying it around the pump case to the

discharge. As liquid is carried away from the suction side, a lower pressure is created,

which draws liquid in through the suction line.