Method and apparatus for detecting and controlling imbalance conditions in a centrifuge system

• US 6,635,007 B2
• Filed: 07/17/2001
• Issued: 10/21/2003
• Est. Priority Date: 07/17/2000
• Status: Active Grant

• Current Assignee: Thermo IEC, Inc. (Thermo Fisher Scientific Incorporated)
• Original Assignee: Thermo IEC, Inc. (Thermo Fisher Scientific Incorporated)
• Inventors: McMahon, Dara, Evans, Robert R. III
• Primary Examiner(s): Cooley, Charles E.
• Application Number:
  US09/908,458
• Publication Number:
  US 20020077239A1
• Time in Patent Office: 826 Days
• Field of Search: 494/1, 494/7, 494/9, 494/10, 494/11, 494/12, 494/16, 494/20, 494/37, 494/82, 494/84, 210/85, 210/144, 318/460, 318/470, 745/74, 324/162, 73/66, 734/57, 734/60, 734/62, 68/231, 682/33, 68/120.6
• US Class Current: 494/7
• CPC Class Codes: B04B 13/00 Control arrangements specially designed for centrifuges; Programme control of centrifuges control arrangements for feed, charge, or discharge B04B11/00
• CPC Class Codes: B04B 9/146 Unbalance detection devices
• CPC Class Codes: G01H 1/003 of rotating machines G01H1/10 takes precedence

Abstract

A method and apparatus for controlling a centrifuge system, the centrifuge system including a rotor and a motor operatively coupled to the rotor, the apparatus including an accelerometer coupled to the centrifuge system so as to measure an acceleration of at least a portion of the centrifuge system during operation of the centrifuge system to provide an acceleration signal, a filter that receives the acceleration signal and provides a filtered acceleration signal, and a controller that receives the displacement signal and controls the centrifuge system in response to the displacement signal.

Claims

1. An apparatus for controlling a centrifuge system, the centrifuge system including a rotor and a motor operatively coupled to the rotor, the apparatus comprising:

an accelerometer coupled to the centrifuge system so as to measure an acceleration of at least a portion of the centrifuge system during operation of the centrifuge system to provide an acceleration signal;

an integrator that receives the acceleration signal and integrates the acceleration signal to provide a displacement signal that represents a displacement of at least one of the motor and the rotor of the centrifuge system; and

a controller that receives the displacement signal and controls the centrifuge system in response to the displacement signal.

2. The apparatus of claim 1, wherein the controller receives the acceleration signal and compares the acceleration signal with a reference signal and provides a control signal when a magnitude of the acceleration signal is larger than a magnitude of the reference signal.

3. The apparatus of claim 2, wherein the centrifuge system is shut down in response to the control signal.

4. The apparatus of claim 2, wherein a rotational speed of the rotor is reduced in response to the control signal.

5. The apparatus of claim 2, wherein the acceleration signal is a voltage.

6. The apparatus of claim 2, wherein the acceleration signal is a current.

7. The apparatus of claim 1, wherein the acceleration is in a radial direction, perpendicular to an axis of rotation of rotor.

8. The apparatus of claim 1, wherein the acceleration is in a longitudinal direction, along an axis of rotation of the rotor.

9. The apparatus of claim 1, wherein the acceleration is in a direction generally perpendicular to an axis of rotation of the motor.

10. The apparatus of claim 1, wherein the acceleration is a result of an imbalance condition in the rotor.

11. The apparatus of claim 10, wherein the acceleration is caused by vibrations of the rotor having range of frequencies when the rotor is spinning and wherein the apparatus further comprises means for determining a range of frequencies that the accelerometer will sense.

12. The apparatus of claim 1, wherein the accelerometer is an integrated circuit.

13. The apparatus of claim 1, wherein the accelerometer is a monolithic integrated circuit.

14. The apparatus of claim 1, further comprising a filter that receives the acceleration signal from the accelerometer and provides a filtered acceleration signal to the controller.

15. The apparatus of claim 14, wherein the filter comprises a high-pass filter.

16. The apparatus of claim 14, wherein the filter comprises a bandpass filter.

17. The apparatus of claim 14, wherein the filter comprises a low-pass filter.

18. The apparatus of claim 1, wherein the integrator integrates the acceleration signal to provide a velocity signal and then integrates the velocity signal to provide the displacement signal.

19. The apparatus of claim 1, wherein the integrator includes an operational amplifier and a capacitor.

20. The apparatus of claim 1, wherein the displacement signal is a voltage.

21. The apparatus of claim 1, wherein the displacement signal is a current.

22. An apparatus for controlling a centrifuge system, the centrifuge system including a rotor and a motor operatively coupled to the rotor, the apparatus comprising:

means for measuring an acceleration of at least a portion of the centrifuge system during the operation of the centrifuge system to provide an acceleration signal;

a filter including an integrator that receives the acceleration signal and integrates the acceleration signal to provide a displacement signal that represents a displacement of at least one of the motor and the rotor of the centrifuge system; and

means for controlling the centrifuge system in response to the displacement signal.

23. The apparatus of claim 22, wherein the filter includes means for providing a filtered acceleration signal to the means for controlling.

24. A method of controlling a centrifuge system, the centrifuge system including a rotor and a motor operatively coupled to the rotor, the method comprising the steps of:

measuring an acceleration of at least a portion of the centrifuge system during operation of the centrifuge system to provide an acceleration signal;

integrating the acceleration signal to provide a displacement signal that represents a displacement of at least one of the motor and the rotor of the centrifuge system; and

controlling the centrifuge system in response to the displacement signal.

25. The method of claim 24, wherein the step of controlling the centrifuge system further comprises comparing the acceleration signal with a reference signal and providing a control signal when a magnitude of the acceleration signal is larger than a magnitude of the reference signal.

26. The method of claim 25, wherein the control signal shuts off the centrifuge system.

27. The method of claim 25, wherein the centrifuge system responds to the control signal to reduce a rotational speed of the rotor.

28. The method of claim 24, wherein the step of integrating further includes integrating the acceleration signal to provide a velocity signal and then integrating the velocity signal to provide the displacement signal.

29. The method of claim 26, wherein the acceleration is caused by vibrations of the rotor having a range of frequencies and wherein the method further comprises the step of determining a range of frequencies that will be sensed when measuring the acceleration.

30. The method of claim 29 wherein the step of determining a range of frequencies includes filtering the range of frequencies to provide a filtered acceleration signal.

31. The method of claim 30, wherein the step of filtering the range of frequencies includes high-pass filtering the range of frequencies.

32. The method of claim 30, wherein the step of filtering the range of frequencies including band-pass filtering the range of frequencies.

33. The method of claim 30, wherein the step of filtering the range of frequencies includes low-pass filtering the range of frequencies.