Lobe pumps are similar to external gear pumps in operation in that fluid flows around the interior of the casing. ... As the lobes come out of mesh, they create expanding volume on the inlet side of the pump. Liquid flows into the cavity and is trapped by the lobes as they rotate.
Lobe Pumps are self-priming , valveless, positive displacement pumps. ... This vacuum draws the liquid into the pump chamber. With further rotation, the pumped medium is conveyed past the pump wall into the pressure area.
Lobe pumps are designed so the rotor does not touch any part of the housing. This allows the pump to run dry with only a small increase in temperature and without the risk of damage to any part of the unit.