T-Rotor Pumps

 A-Ryung Trochiod Rotor Pump (T-Pump)

T-Rotor pump is as internal gear pump in which a couple of rotors
inner rolling movement along the trochoid curves forming a space
from where a charging and discharging forces are produced.
Outer rotor makes rotating movement with inner rotor that has less
gear than itself by one tooth and they are pivoted together so that
rotate about the same axis. Above picture shows rotor movement.