Scroll pump

These pumps are seen in many applications and have a higher capacity then double row type. Fluid enters the pump and is screwed by the idler shafts along the outer edge to the discharge port. Axial thrust of the idlers is absorbed by the integral thrust collar of the driven shaft. The axial thrust of the driven shaft is absorbed by the thrust bearing.
The scroll sit in a replaceable insert which is sealed to the outer casing by o-rings.source(arab-training.com)