US4700117A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Centrifuge overspeed protection and imbalance detection system
Assignee: Beckman Coulter Inc
•
Filing: 1985-05-31
•
Granted: 1987-10-13
•
Expires: 2005-05-31
Abstract
Abstract A centrifuge overspeed protection and imbalance detection system is structured to provide a method for detecting rotor imbalance and rotor overspeed. The system has a single transducer to provide real-time data necessary to detect rotor imbalance and control motor speed. Motor speed is controlled by synthesis of a drive frequency signal for driving the inverter motor control. The drive frequency signal may be inhibited to provide slow acceleration or deceleration, or to shut the motor off by providing a zero slip frequency. Motor control is responsive to a Rotor Identification circuit and operator programming, as well as a closed loop response to the real time tach signal. Imbalance detection is provided by counting tach pulses in each of a plurality of intervals, detecting deviations in tach pulse rate and sounding an alarm when the irregularity of tach pulse signals exceeds the limits of a predetermined standard deviation.
Inventors
- 👤 Robert H. Giebeler
- 👤 Christopher W. Parkes
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 10:26
CPC Classifications
H; H02; H02H; H02H7/00; H02H7/08; H02H7/093; B; B04; B04B; B04B13/00; B04B13/003; B04B9/00; B04B9/14; B04B9/146; Y; Y10; Y10S; Y10S388/00; Y10S388/907; Y10S388/912
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
103 words
A method for high speed centrifuge rotor imbalance detection, the steps of which comprising: deriving a tach signal frequency which corresponds to the actual speed of a centrifuge rotor when said rotor is in balance and deviates therefrom when said rotor is out of balance; determining the tach frequency signal derived for a plurality of discrete intervals; calculating by means of a central processing unit any differences between the frequencies computed for each of the discrete intervals and deriving therefrom a deviation frequency signal; measuring the deviation frequency signal derived against a predetermined standard, thereby detecting the presence of high speed rotor imbalance.
Claim 2
Independent Claim
103 words
A method for high speed centrifuge rotor imbalance detection, the steps of which comprising: deriving a tach signal frequency which corresponds to the actual speed of a centrifuge rotor when said rotor is in balance and deviates therefrom when said rotor is out of balance; determining the tach frequency signal derived for a plurality of discrete intervals; calculating by means of a central processing unit any differences between the frequencies computed for each of the discrete intervals and deriving therefrom a deviation frequency signal; measuring the deviation frequency signal derived against a predetermined standard, thereby detecting the presence of high speed rotor imbalance.
Claim 3
Independent Claim
153 words
A system for the detection of high speed centrifuge rotor imbalance, comprising: means for sensing true rotor speed when said rotor is in balance and generating a rotor tach signal having a frequency proportional thereto; means for measuring the frequency of the rotor tach signal at a plurality of sampling intervals; means for generating a dynamic reference frequency, said dynamic reference frequency being a reference frequency derived according to expected rotor operating conditions when the rotor is in proper balance; said dynamic reference frequency changing with time as rotor speed and acceleration change; comparing means for comparing the frequency of the rotor tach signal sampled at each of a plurality of intervals to the dynamic reference frequency and deriving a deviation frequency; and means for processing the deviation frequency and determining whether said deviation frequency exceeds a predetermined range, whereby centrifuge rotor imbalance is detected when said deviation frequency exceeds said predetermined range.
Claim 4
Independent Claim
153 words
A system for the detection of high speed centrifuge rotor imbalance, comprising: means for sensing true rotor speed when said rotor is in balance and generating a rotor tach signal having a frequency proportional thereto; means for measuring the frequency of the rotor tach signal at a plurality of sampling intervals; means for generating a dynamic reference frequency, said dynamic reference frequency being a reference frequency derived according to expected rotor operating conditions when the rotor is in proper balance; said dynamic reference frequency changing with time as rotor speed and acceleration change; comparing means for comparing the frequency of the rotor tach signal sampled at each of a plurality of intervals to the dynamic reference frequency and deriving a deviation frequency; and means for processing the deviation frequency and determining whether said deviation frequency exceeds a predetermined range, whereby centrifuge rotor imbalance is detected when said deviation frequency exceeds said predetermined range.
Claim 5
Dependent Claim
79 words
In determining irregularities in the operation of said centrifuge, the steps of which comprise: deriving a tach signal during the operation of said centrifuge; determining the frequency of said tach signal during a plurality of discrete intervals; detecting any differences between any of the frequencies determined for each of the discrete intervals and an expected frequency; and, comparing said detected difference against a known standard thereby detecting the existence of irregularity in the operation of said high speed centrifuge.
Claim 6
Dependent Claim
79 words
In determining irregularities in the operation of said centrifuge, the steps of which comprise: deriving a tach signal during the operation of said centrifuge; determining the frequency of said tach signal during a plurality of discrete intervals; detecting any differences between any of the frequencies determined for each of the discrete intervals and an expected frequency; and, comparing said detected difference against a known standard thereby detecting the existence of irregularity in the operation of said high speed centrifuge.
Claim 7
Dependent Claim
62 words
In a centrifuge a system for the detection of rotor imbalance comprising: signal generating means for generating an electrical signal having a frequency indicative of acutal rotor speed when the centrifuge rotor is in balance and which deviates therefrom when said rotor is out of balance; and means signalling the deviation of said frequency from an expected value by a predetermined amount.
Claim 8
Dependent Claim
62 words
In a centrifuge a system for the detection of rotor imbalance comprising: signal generating means for generating an electrical signal having a frequency indicative of acutal rotor speed when the centrifuge rotor is in balance and which deviates therefrom when said rotor is out of balance; and means signalling the deviation of said frequency from an expected value by a predetermined amount.
Claim 9
Dependent Claim
48 words
The system according to claim 4 for the further detection of rotor overspeed comprising: means comparing said frequency of said electrical signal against a frequency indicative of the maximum safe speed for said rotor and generating a signal indicating that said rotor has exceeded said maximum rotor speed.
Claim 10
Dependent Claim
126 words
In a centrifuge a system for the detection of rotor imbalance comprising: signal generating means for generating an electrical signal having a frequency indicative of actual rotor speed when the centrifuge rotor is in balance and which deviates therefrom when said rotor is out of balance; means for generating a reference signal having a frequency derived according to expected conditions when said rotor is in proper balance; comparison means for comparing the frequency of said electrical signal from said signal generting means with the frequency of said reference signal; and deviation signal generating means for generating an output signal when the frequency of said electrical signal deviates from the frequency of said reference signal by a predetermined amount whereby centrifuge rotor imbalance is detected and signalled.
Claim 11
Dependent Claim
126 words
In a centrifuge a system for the detection of rotor imbalance comprising: signal generating means for generating an electrical signal having a frequency indicative of actual rotor speed when the centrifuge rotor is in balance and which deviates therefrom when said rotor is out of balance; means for generating a reference signal having a frequency derived according to expected conditions when said rotor is in proper balance; comparison means for comparing the frequency of said electrical signal from said signal generting means with the frequency of said reference signal; and deviation signal generating means for generating an output signal when the frequency of said electrical signal deviates from the frequency of said reference signal by a predetermined amount whereby centrifuge rotor imbalance is detected and signalled.
Claim 12
Independent Claim
220 words
A system for the detection of centrifuge rotor overspeed and imbalance comprising: signal generating means for generating an electrical signal having a characteristic indicative of acutal rotor speed when the centrifuge rotor is in balance and which deviates therefrom when said rotor is out of balance said electrical signal also having a characteristic identifying the particular rotor present; means receiving said electrical signal and generating an output indicating the maximum speed for the identified rotor; means for generating an output signal when said electrical signal indicates that the actual rotor speed has exceeded the maximum speed for said identified rotor; means for measuring the speed indicating characteristic of said electrical signal at a plurality of sampling intervals; means for generating a dynamic reference characteristic, said dynamic reference characteristic being a reference characteristic derived according to expected rotor operating conditions when said rotor is in proper balance, said dynamic reference characteristic changing with time as rotor speed and acceleration change; comparing means for comparing the characteristic of said electrical signal sampled at each of a plurality of intervals to the dynamic reference characteristic and deriving a deviation characteristic; and means for processing the deviation characteristic and determining whether said deviation characteristic exceeds a predetermined range and generating an output signal when said range is exceeded whereby centrifuge rotor imbalance is detected.
Claim 13
Independent Claim
220 words
A system for the detection of centrifuge rotor overspeed and imbalance comprising: signal generating means for generating an electrical signal having a characteristic indicative of acutal rotor speed when the centrifuge rotor is in balance and which deviates therefrom when said rotor is out of balance said electrical signal also having a characteristic identifying the particular rotor present; means receiving said electrical signal and generating an output indicating the maximum speed for the identified rotor; means for generating an output signal when said electrical signal indicates that the actual rotor speed has exceeded the maximum speed for said identified rotor; means for measuring the speed indicating characteristic of said electrical signal at a plurality of sampling intervals; means for generating a dynamic reference characteristic, said dynamic reference characteristic being a reference characteristic derived according to expected rotor operating conditions when said rotor is in proper balance, said dynamic reference characteristic changing with time as rotor speed and acceleration change; comparing means for comparing the characteristic of said electrical signal sampled at each of a plurality of intervals to the dynamic reference characteristic and deriving a deviation characteristic; and means for processing the deviation characteristic and determining whether said deviation characteristic exceeds a predetermined range and generating an output signal when said range is exceeded whereby centrifuge rotor imbalance is detected.
Claim 14
Dependent Claim
12 words
The system according to claim 7 wherein said signal characteristic is frequency.
References Cited (Backward Citations)
US3982162A
Cited
US3746247A
Cited
US4419615A
Cited
US4491019A
Cited
US4601696A
Cited
US4551715A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1990-10-12 | 1991-04-13 | 1991-10-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-10-12 | 1995-04-13 | 1995-10-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-10-12 | 1999-04-13 | 1999-10-13 | $7700.00 | Window Closed / Lapsed |