Rotary vane pump

Claim 1

A ROTARY PUMP COMPRISING: MEANS FORMING A GENERALLY HEMISPHERICAL CHAMBER INCLUDING A CENTRALLY APERTURED FLAT REAR WALL AND A CONCAVE HEMISPHERICAL FRONT WALL; A ROTATABLE DRIVE SHAFT EXTENDING INTO THE CHAMBER THROUGH THE REAR WALL APERTURE AND TERMINATING FORWARDLY IN A ROTOR HAVING A FORWARDLY DIRECTED CONVEX HEMISPHERICAL SURFACE AND A PAIR OF OPPOSITELY DIRECTED PIVOT PINS PROJECTING RADIALLY OF THE DRIVE SHAFT AXIS FROM SAID CONVEX SURFACE AND IN SLIDABLE SEALING CONTACT WITH SAID REAR WALL; AN IMPELLER INCLUDING A PAIR OF SEMI-ANNULAR VANES JOINED AT A HUB PORTION TO FORM A DIHEDRAL ANGLE BETWEEN THE VANES, THE HUB BEING ROCKABLY AND SEALABLY MOUNTED ON SAID PINS, THE OUTER AND INNER ARCUATE PERIMETERS OF THE VANES BEING IN SEALING RELATION WITH, RESPECTIVELY, SAID CONCAVE FRONT WALL AND SAID CONVEX SURFACE; MEANS FOR PIVOTING SAID IMPELLER ABOUT THE VERTEX OF SAID DIHEDRAL ANGLE DURING ROTATION OF SAID SHAFT, THE IMPELLER AND SAID PIVOTING MEANS DIVIDING SAID CHAMBER INTO A PLURALITY OF COMPARTMENTS OF CYCLICALLY VARYING VOLUMES; AND INLET AND OUTLET PORTS FORMED IN SAID CONCAVE FRONT WALL