Rotary pump

Claim 1

IN A ROTARY PUMP, A CLOSED CASING COMPRISING A BODY AND A COVER, THE BODY HAVING INLET AND OUTLET PASSAGES AND AN OPENING EXTENDING INTO INLET AND OUTLET PASSAGES, THE BODY BEING PROVIDED WITH INNER AND OUTER CONCENTRIC CYLINDRICAL WALLS DEFINING A WORKING SPACE, PARTITION MEANS FORMING AN INTEGRAL PART OF SAID BODY IN SAID WORKING SPACE AND SEPARATING THE INLET PASSAGE FROM THE OUTLET PASSAGE, AND DIVIDING THE OPENING TO PROVIDE TWO SEPARATE OPENINGS, A PISTON ADAPTED TO OPERATE IN SAID CASING, SAID PISTON HAVING INNER AND OUTER CYLINDERS, SAID OUTER CYLINDER OPERATING IN SAID WORKING SPACE AND DEFINING INNER AND OUTER PUMP CHAMBERS IN SAID WORKING SPACE, SAID PISTON HAVING AN END PLATE OUTSIDE THE WORKING SPACE, SAID OUTER CYLINDER BEING SLOTTED FOR MOVEMENT ABOUT THE PARTITION MEANS, A DRIVE SHAFT ROTATABLY JOURNALLED IN SAID CASING, AN ECCENTRIC MOUNTED ON SAID DRIVE SHAFT, SAID ECCENTRIC BEING ROTATABLY MOUNTED IN SAID INNER CYLINDER OF SAID PISTON AND SERVING TO TRANSMIT WORKING MOVEMENTS FROM THE DRIVE SHAFT TO THE PISTON AS THE SHAFT IS ROTATED, SAID SHAFT HAVING A COLLAR FOR ENGAGING THE PLATE ON THE PISTON, ANNULARLY CONTINUOUS RESILIENT SEALING MEANS DISPOSED BETWEEN THE ENDS OF THE INNER AND OUTER CONCENTRIC CYLINDRICAL WALLS AND SAID PLATE FOR ESTABLISHING A UNIFORM PRESSURE TYPE SEAL BETWEEN THE SAME, MEANS FOR APPLYING FORCE TO SAID SHAFT TO DRAW SAID PLATE TOWARDS THE ENDS OF THE INNER AND OUTER CYLINDRICAL WALLS AND CONTROL MEANS MOUNTED ON SAID END PLATE OF SAID PISTON AND ON THE COVER AND SERVING TO CAUSE CIRCULAR GYRATORY MOVEMENT OF SAID PISTON WITHOUT AXIAL ROTATION AS SAID PISTON IS MOVED BY ROTATION OF SAID DRIVE SHAFT.