Detection of dynamic unbalances of centrifuges

• US 4,491,019 A
• Filed: 12/16/1982
• Issued: 01/01/1985
• Est. Priority Date: 12/24/1981
• Status: Expired due to Fees

• Current Assignee: Kontron Instruments Holding, N.V.
• Original Assignee: Kontron Holding AG (Roche Holding AG)
• Inventors: Wicki, Gerhard, Naff, Rolf
• Primary Examiner(s): NOT, DEFINED
• Application Number:
  US06/450,217
• Time in Patent Office: 747 Days
• Field of Search: 73/462, 73/660, 73/457, 338/32 H, 340/683, 494/7
• US Class Current: 73/457
• CPC Class Codes: B04B 9/146 Unbalance detection devices

Abstract

In accordance with the invention, a magnetic field sensor is disposed on a stationary part of a centrifuge near an annular member of a rotor and is adapted to detect those variations in a gap which exists between the annular member and the sensor. The variations in the gap arising from deflection and/or precession of the rotor axis.

Claims

1. An apparatus for detecting imbalance of a centrifuge comprising:

(a) a centrifuge having;

(i) a stationary portion;

(ii) a magnetic field sensor means disposed on the stationary portion;

(iii) a rotor means disposed above said stationary portion;

(iv) a rotor shaft rotatably connecting the rotor means with the stationary portion, the rotor shaft rotating with said rotor means; and

(v) an annular member fixedly attached to the rotor means for rotation therewith and having an annular end surface positioned in a plane generally perpendicular to the longitudinal axis of the rotor shaft, said annular end surface located and disposed at a predetermined distance above the sensor means thereby forming a predetermined gap between the sensor means and the annular end surface, wherein the sensor means generates a signal when the dimension of the gap between the annular end surface and sensor means is altered due to imbalance of the centrifuge; and

(b) electronic circuit means for processing the signal from the sensor means so as to activate an alarm signal upon imbalance of the centrifuge.

2. The apparatus of claim 1 wherein the annular member is a coaxial flange-like member made of soft iron.

3. The apparatus of claim 2 wherein the sensor means is a magnetic-field-dependent resistance or a Hall generator.

4. The apparatus of claim 3 wherein the sensor means is a magnetic-field-dependent resistance.

5. The apparatus of claim 3 wherein the sensor means is a Hall generator.

6. The apparatus of claim 2 wherein the sensor is a differential sensor having two magnetic-field-dependent resistances disposed on a permanent magnet.

7. The apparatus of claim 1 wherein the rotor means includes a rotor.

8. The apparatus of claim 1 wherein the rotor means includes

(i) a rotor disposed above the stationary portion;

and

(ii) an adapter having a portion disposed within the rotor for rotation therewith, and the annular member is fixedly attached to the adapter.

9. The apparatus of claim 1 wherein the rotor means includes

(i) a rotor disposed above the stationary portion;

and

(ii) an adapter having a portion disposed within the rotor for rotation therewith, and the annular member forms an integral flange with said adapter.

10. The apparatus of claim 1 wherein the rotor means includes a rotor and the annular member is fixedly attached to the rotor for rotation therewith.

11. The apparatus of claim 1 wherein the centrifuge is an ultracentrifuge.