US5651667A
Expired / Lapsed
US
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Cryopump synchronous motor load monitor
Assignee: Azenta Inc
•
Filing: 1994-01-18
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Granted: 1997-07-29
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Expires: 2014-01-18
Abstract
Abstract An apparatus and method for monitoring the torque load condition of a cryopump motor includes a power transducer for monitoring the electrical power input to the cryopump motor. A preferred embodiment of the power transducer includes a Hall-effect multiplier which measures the instantaneous and average electrical power input to the cryopump motor to determine torque load. Another preferred embodiment includes a power transducer which measures the Power Factor of the electrical power input to the cryopump motor to determine torque load. The Power Factor transducer includes a phase detector which detects the phase difference between the input voltage and the input current applied to the cryopump motor.
Inventors
- 👤 William T. Sand
- 👤 Martin Stein
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 21:41
CPC Classifications
B; B01; B01D; B01D8/00; F; F25; F25B; F25B9/00; F25B9/14; G; G01; G01L; G01L3/00; F25B2309/00; F25B2309/14; F25B2309/1428; Y; Y02; Y02P; Y02P70/00; Y02P70/10
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
51 words
A method for monitoring and detecting internal degradation of a cryogenic refrigerator, comprising the steps of monitoring the electrical power input to a motor which drives a displacer of the cryogenic refrigerator, and relating the power input to the internal degradation including mechanical wear and refrigerant contamination of the cryogenic refrigerator.
Claim 2
Independent Claim
51 words
A method for monitoring and detecting internal degradation of a cryogenic refrigerator, comprising the steps of monitoring the electrical power input to a motor which drives a displacer of the cryogenic refrigerator, and relating the power input to the internal degradation including mechanical wear and refrigerant contamination of the cryogenic refrigerator.
Claim 3
Dependent Claim
31 words
The method of claim 1 wherein the monitoring step includes measuring the electrical power input to the cryopump and displaying the power input to show instantaneous power consumption of the motor.
Claim 4
Dependent Claim
26 words
The method of claim 1 wherein the monitoring step includes measuring the electrical power input to the motor and displaying the power input averaged over time.
Claim 5
Dependent Claim
66 words
The method of claim 3 wherein the monitoring step includes measuring the maximum average of the electrical power, measuring the minimum average of the electrical power, and subtracting the minimum average of the electrical power from the maximum average of the electrical power to determine a torque load on the motor which is insensitive to an operating voltage and a temperature of windings of the motor.
Claim 6
Dependent Claim
22 words
The method of claim 1 wherein the monitoring step includes measuring a power factor of the power input to the cryopump motor.
Claim 7
Dependent Claim
58 words
A cryopump, comprising: a displacer for moving a working fluid through a regenerator; a motor for driving the displacer; a torque monitoring device for generating a torque signal indicative of a torque generated by the motor; and a display device for providing a visual display of the torque generated by the motor in response to the torque signal.
Claim 8
Dependent Claim
58 words
A cryopump, comprising: a displacer for moving a working fluid through a regenerator; a motor for driving the displacer; a torque monitoring device for generating a torque signal indicative of a torque generated by the motor; and a display device for providing a visual display of the torque generated by the motor in response to the torque signal.
Claim 9
Dependent Claim
38 words
A cryopump as claimed in claim 6, further comprising an audible alarm device for generating an audible signal to a user in response to the torque signal being indicative of the torque exceeding a threshold level of torque.
Claim 10
Dependent Claim
45 words
A cryopump comprising: a displacer for moving a working fluid through a regenerator; a motor for driving the displacer; and a torque monitoring device for generating a peak torque signal indicative of a peak torque generated by the motor during duty cycles of the displacer.
Claim 11
Dependent Claim
45 words
A cryopump comprising: a displacer for moving a working fluid through a regenerator; a motor for driving the displacer; and a torque monitoring device for generating a peak torque signal indicative of a peak torque generated by the motor during duty cycles of the displacer.
Claim 12
Dependent Claim
31 words
A cryopump as claimed in claim 8, further comprising a display device for providing a display of the peak torque during the duty cycles in response to the peak torque signal.
Claim 13
Dependent Claim
27 words
A cryopump as claimed in claim 9, further comprising an alarm for generating an audible signal in response to the peak torque signal exceeding a predetermined threshold.
Claim 14
Dependent Claim
26 words
A cryopump as claimed in claim 8, further comprising a display device for indicating contamination of the working fluid in response to the peak torque signal.
Claim 15
Dependent Claim
37 words
A cryopump as claimed in claim 8, further comprising an alarm for generating an audible signal indicating levels of working fluid contamination of the working fluid in response to the peak torque signal exceeding a threshold value.
Claim 16
Dependent Claim
30 words
A cryopump as claimed in claim 8, wherein the torque monitoring device comprises a power transducer for generating a transducer signal indicative of an electrical power input to the motor.
Claim 17
Dependent Claim
39 words
A cryopump as claimed in claim 13, wherein the torque monitoring device further comprises a low pass filter for filtering the transducer signal to produce a low pass filtered signal representative of average electrical power input to the motor.
Claim 18
Dependent Claim
47 words
A cryopump as claimed in claim 14, wherein the torque monitoring device further comprises a maximum signal detector for detecting the peak torque of the motor for each duty cycle in response to the low pass filtered signal and a synchronizing signal indicative of the duty cycles.
Claim 19
Dependent Claim
42 words
A cryopump as claimed in claim 15, wherein the torque monitoring device further comprises a minimum signal detector for detecting a minimum torque of the motor for each duty cycle in response to the low pass filtered signal and the synchronizing signal.
Claim 20
Dependent Claim
30 words
A cryopump as claimed in claim 16, further comprising an averaging circuit for producing average of the torque produced by the motor in response to the low pass filtered signal.
Claim 21
Dependent Claim
35 words
A cryopump as claimed in claim 17, further comprising a reset circuit for resetting the maximum signal detector and the minimum signal detector in response to the synchronizing signal to begin a new comparison cycle.
Claim 22
Dependent Claim
23 words
A cryogenic refrigerator as claimed in claim 8, wherein the torque monitoring device monitors the torque by measuring power consumed by the motor.
Claim 23
Independent Claim
121 words
A method for detecting refrigerant contamination in a cryopump including a displacer for moving a refrigerant through a regenerator, a motor, a crosshead for converting rotary motion of the motor into linear motion for driving the displacer, and a torque monitoring device for detecting torque generated by the motor, the method comprising: monitoring the torque of the motor during a current duty cycle of the displacer; comparing the monitored torque to the torque generated by the motor during a previous duty cycle of the displacer; and generating signal to a user indicating the presence of contamination in the refrigerant in response to the comparison of the torque generated by the motor during the present duty cycle and the previous duty cycle.
Claim 24
Independent Claim
121 words
A method for detecting refrigerant contamination in a cryopump including a displacer for moving a refrigerant through a regenerator, a motor, a crosshead for converting rotary motion of the motor into linear motion for driving the displacer, and a torque monitoring device for detecting torque generated by the motor, the method comprising: monitoring the torque of the motor during a current duty cycle of the displacer; comparing the monitored torque to the torque generated by the motor during a previous duty cycle of the displacer; and generating signal to a user indicating the presence of contamination in the refrigerant in response to the comparison of the torque generated by the motor during the present duty cycle and the previous duty cycle.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2000-07-28 | 2001-01-27 | 2001-07-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2004-07-28 | 2005-01-27 | 2005-07-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2008-07-28 | 2009-01-27 | 2009-07-29 | $7700.00 | Window Closed / Lapsed |