Driving device for an agitator shaft

Claim 1

A DRIVE ARRANGEMENT FOR DRIVING AN AGITATOR IN A PRESSURE VESSEL COMPRISING, IN COMBINATION, A PRESSURE VESSEL ADAPTED TO CONTAIN A FLUID UNDER PRESSURE DIFFERING FROM ATMOSPHERIC PRESSURE; A PRESSURE CHAMBER PROJECTING FROM SAID PRESSURE VESSEL CONNECTED THERETO; PASSAGE MEANS AT ONE END OF SAID PRESSURE CHAMBER AND PROVIDING COMMUNICATION BETWEEN SAID PRESSURE CHAMBER AND SAID PRESSURE VESSEL; CLOSURE MEANS AT THE OTHER END OF SAID PRESSURE CHAMBER FOR CLOSING SAID OTHER END THEREOF AND BEING FORMED WITH AN APERTURE ALIGNED ALONG A COMMON AXIS WITH SAID PASSAGE MEANS AND HAVING NORMAL TO SAID AXIS A PREDETERMINED CROSS SECTION SMALLER THAN THE CROSS SECTION OF SAID PASSAGE MEANS; A DRIVE SHAFT COAXIAL WITH SAID COMMON AXIS AND HAVING A LARGE DIAMETER PORTION EXTENDING FROM THE INTERIOR OF SAID PRESSURE VESSEL THROUGH SAID PASSAGE MEANS INTO SAID PRESSURE CHAMBER AND A SMALL DIAMETER SHAFT PORTION OF A DIAMETER SUBSTANTIALLY SMALLER THAN SAID LARGE DIAMETER SHAFT PORTION AND OF A CROSS SECTION SMALLER THAN SAID PREDETERMINED CROSS