GB1387045A - Centrifuges - Google Patents

Abstract

1387045 Preventing vibration of centrifuge rotor IVAN SORVALL INC 25 May 1972 [28 June 1971] 24793/72 Heading B2P [Also in Divisions E2 and F2] A centrifuge comprises a frame (12), Fig. 1 (not shown), a vertical rotatable drive shaft 32 supported on the frame, a rotor (71), 73, a rotor shaft 52 having one end portion 51 pivotally connected to the drive shaft and rotated thereby and the other end portion 53 operably pivotally connected to the rotor, and an articulating connection 57, 89 provided between the rotor and the drive shaft and movable in a horizontal plane relative to the vertical axis of the drive shaft when the rotor shaft 52 moves pivotally and the centre of gravity of the spinning rotor moves to become aligned with the axis of rotation of the drive shaft. The drive shaft 32 is mounted in bearings 34 in a housing 16 which is supported by a resilient rubber cushion 21 on a mounting ring 13 bolted to the frame. A power shaft 11 is driven by an electric motor, a turbine, a belt and pulley combination, or gearing, and is connected to the shaft 32 by a resilient coupling 24-28. The upper end of shaft 32 terminates in an enlarged crown 41 having a skirt 42 defining a chamber 43 in which a slide block 57 is horizontally movably mounted on a ball thrust bearing 56 and is retained against undue free movement between the latter and a friction ring 58 by a spring washer 59 engaged below a flange 45 formed on a clamp ring 44 threadably connected to crown 41. Clamp ring 44 may be provided with radially and vertically extending slots (61), Fig. 4 (not shown), within which centrifugal locking levers 62 are pivotally mounted on pins 63 and above a predetermined speed bear upon friction ring 58 to cause the latter to lock sliding-block 57 in an immovable position. The hub 73 of the rotor (71) has a recess 77 which accommodates a bearing block 78 retained by a clamp ring 82 having a flange 84 upon which rests a spring washer 86 which supports a friction ring 87. A universal hollow ball joint 89 slidably engages bearing surfaces 79, 81 on the bearing block and a seat 88 on the ring 87. The ball joint is integrally formed with a tapered sleeve 91 which is secured within a collar 92 on the sliding block 57 by a nut 93. The rotor shaft 52 has square ball ends 51, 53 which are pivotally accommodated in square-shaped apertures in inserts 47, 76 secured in annular recesses 46, 74 in crown 41 and hub 73 respectively. In operation, during the start-up or slowing down period, any imbalance of the rotor causes the geometric centre of the rotor and of the hub 73 to depart from the axis of rotation of the drive shaft 32, this being permitted by the sliding action of the block 57 and the pivoting action of the shaft 52. Consequently, the combined centre of gravity of the rotor and hub is brought into alignment with the axis of rotation of the shaft 32 thereby preventing vibration of the rotor, when the rotor attains a predetermined speed the levers 62 lock the sliding block 57 securely between the friction ring 58 and the bearing 56.