An internal gear pump consists of an inner rotor and an outer rotor. Both inner and outer rotors rotate in the same direction.
Because the number of teeth and the center of each are different, the volume of the gap between the rotors varies. As a result the pump intakes and discharges liquid. The simple structure allows for a compact design.
The internal gear pump is able to feed a high viscous liquid and take a high pressure. Feeding of lubricating oil or hydraulic oil is a typical application. In addition to regular products, there are WO versions to spray or transfer bunker oil an PL versions to transfer chemical materials such as isocyanate.
The 3FA pump is for large capacity and mid pressure hydraulic and lubrication applications. Since this pump is relatively small, there are many cases that the pump is integrated into a machine. The rotation direction is clockwise, opposite to types 1A, 1HG and 2A.