GB1108694A - Vacuum centrifuge - Google Patents

Abstract

1,108,694. Centrifugal separators. M. CHRIST. 9 June, 1965 [10 June, 1964], No. 19394/65. Heading B2P. [Also in Division F2] The shaft 7 of a centrifuge rotor which rotates in an evacuated chamber 1 is sealed where it passes through the chamber wall by means of an oil-lubricated gland 9 to which oil is supplied from a tank 11 via pipe 10, oil leaking from the gland being automatically returned to the tank 11: The centrifuge may be of the ultracentrifuge type having a rotor speed of 60,000 r.p.m. The chamber 1 is closed by a removable cover 2 and is evacuated through a pipe 4 by means of a vacuum pump 5. During centrifugation oil leaking from the gland enters a chamber 12 and flows by gravity through a pipe 13 into a tank 14 which is connected by a pipe 15 to a tank 16 itself adapted to be connected via a pipe 17 to the tank 11 upon operation of an electromagnetically operated valve 18 which during centrifugation is normally closed. During centrifugation the chamber 12 and the interior of the tanks 14, 16 are under vacuum. When the vacuum pump 5 is shut upon termination of centrifugation an electromagnetically operated valve 19 opens to admit air in the chamber 1. The air forces the leakage oil which has accumulated in the tank 14 into the tank 16. After a slight delay, the valve 18 in the line 17 opens for the oil to flow from the tank 16 back into the tank 11. The delayed opening of the valve 18 may be achieved by means of a time-lag relay, Fig. 2 (not shown) incorporated in a circuit comprising the valves 18, 19, and their associated electromagnets. Alternatively, the switch 22 operating the electromagnet associated with the valve 18, Fig. 3, is connected in series with a battery B and a switch S which is supported on a bracket 23 fixed to the wall of the chamber 1 and is normally held open during centrifugation. A manuallyoperated switch 28 in series with the battery B and with the switch S is closed during centrifugation but is adapted to be opened when centrifugation stops to prevent the battery from running down when the cover 2 is removed. The switch 28 is opened only when after centrifugation. a certain time has elapsed after the opening of the cover 2, during which time the switch 22 will have caused the valve 18 to open so as to transfer the leakage oil from tank 16 to tank 11. In a modification. the centrifuge drive unit is disposed above the chamber 1 and the drive shaft is provided with a centrifuging plate which conveys leakage oil to a chamber similar to chamber 12 and thence to a tank corresponding to tank 14.