摘要 |
A positive displacement pump (1) comprises a casing with a central body (2) and two closing lids (20), said central body (2) being provided with two cylindrical communicating chambers (22, 23), one suction pipe (I) and one discharge pipe (O), and two rotors (3, 4) revolvingly mounted in said chambers (22, 23) of the central body and supported by shafts (5, 6) revolvingly mounted in said closing lids (20). The two rotors comprise: a male rotor (3) comprising only protuberances (30), not cavities, and a female rotor (4) comprising only cavities (40), not teeth or protuberances. |