Rotary piston pump with slotted pistons - has piston rotors with plates having different thermal expansion coefficient

摘要

The rotary piston pump has two vane-type pistons rotating about parallel oppositely displaced axes in which the pistons (18, 20) have open slots (30) at the outer circumferences of the piston wings. The slots each carry a sealing plate (32) are made of a material of a lower thermal expansion than that of the piston wings. The plates are axially movable in the slots but held radially firm. ADVANTAGE - Rotary piston pump in which the sealing gap between the pistons and the pump housing is kept small.