US3950985A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of and apparatus for monitoring the durability of components of thermal power plants
Assignee: BBC Brown Boveri AG Switzerland
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Filing: 1974-03-25
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Granted: 1976-04-20
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Expires: 1994-03-25
Abstract
Abstract A method for monitoring the durability i.e. the service life of components of a thermal plant where, in functional relation to thermal as well as mechanical stresses, hours eqivalent to those of actual operation of such component at a given correlated mechanical and thermal stress value are counted. The correlated mechanical and thermal stress generated within the component and simulated by an equivalent electrical signal such as a voltage, is compared with a stress, likewise simulated by an electrical signal which at the relevant temperature of the component corresponds to a constant service life assigned by design specification, and the difference between the two electrical signals thus produced is correlated in a non-linear manner to a factor by which the period of actual operation is weighted and integrated, thus arriving at equivalent hours of operation.
Inventors
- 👤 Kurt Buchwald
- 👤 Ludwig Busse
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 12:11
CPC Classifications
G; G07; G07C; G07C3/00; G01; G01K; G01K3/00; G01K3/02; G01K3/04
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
204 words
A method for monitoring the service life of components of a thermal power plant by counting hours equivalent to those of actual operation of the component at a given correlated mechanical and thermal stress value which comprises the steps of a. determining from a constant service life graph the effect of a change in stress for a given temperature relative to a reference service life, b. measuring the temperature of the component, c. determining from the measured temperature the corresponding stress which would give the reference service life, d. measuring the temperature difference between two points in the component corresponding to the thermal stress, e. calculating from the measured temperature difference and known essential mechanical parameters of operation a correlated stress, f. comparing the respective stress values produced by steps c) and e) to g. the difference therebetween, determining from said stress difference and from the effect of the change in stress produced by step a) a weighted factor, h. utilizing said weighted factor to modify the actual measured time, and i. integrating said modified measured time to provide an equivalent time which corresponds to the hours equivalent of that portion of useful life which has been consumed relative to said reference service life.
Claim 2
Independent Claim
204 words
A method for monitoring the service life of components of a thermal power plant by counting hours equivalent to those of actual operation of the component at a given correlated mechanical and thermal stress value which comprises the steps of a. determining from a constant service life graph the effect of a change in stress for a given temperature relative to a reference service life, b. measuring the temperature of the component, c. determining from the measured temperature the corresponding stress which would give the reference service life, d. measuring the temperature difference between two points in the component corresponding to the thermal stress, e. calculating from the measured temperature difference and known essential mechanical parameters of operation a correlated stress, f. comparing the respective stress values produced by steps c) and e) to g. the difference therebetween, determining from said stress difference and from the effect of the change in stress produced by step a) a weighted factor, h. utilizing said weighted factor to modify the actual measured time, and i. integrating said modified measured time to provide an equivalent time which corresponds to the hours equivalent of that portion of useful life which has been consumed relative to said reference service life.
Claim 3
Dependent Claim
37 words
The method as defined in claim 1 wherein the reference service life plotted as a function of temperature is represented by the stress of constant service life based on the design characteristic of the thermal power plant.
Claim 4
Dependent Claim
43 words
The method as defined in claim 1 wherein the component of the thermal power plant being monitored is the rotor element of a turbine and wherein the mechanical parameters of operation involved in calculation of said correlation stress are pressure and centifugal force.
Claim 5
Dependent Claim
294 words
Apparatus for monitoring the service life of components of a thermal power plant by counting hours equivalent to those of actual operation of the component at a given correlated mechanical and thermal stress value comprising: a first thermo-responsive element which measures the temperature at a point on the surface of the component under examination, means connecting the output from said first thermo-responsive element to an electronic function generator through a first buffer amplifier, said function generator producing at its output a first signal representative of a stress for that temperature corresponding to a designed reference service life, a second thermo-responsive element which measures the temperature at a point internally of said component and which is counter-connected with said first thermo-responsive element so as to produce a direct measurement of the temperature difference between said points and which is representative of the thermal stress, means connecting the temperature difference output signal from said counter-connected first and second thermo-responsive elements to an electronic device through a second buffer amplifier, said device combining said temperature difference signal with a known mechanical stress factor to produce at its output a second signal, means for comparing said first and second signals to produce a signal corresponding to the difference therebetween, a pulse generator driven by said difference signal Δσ and which produces pulses at a repetition rate proportional to a base frequency f o when Δσ=0 and which produces pulses at a repetition rate proportional to ##EQU8## when Δσ is not equal to zero, wherein K represents the stress difference corresponding to one decade of service life, and a counter driven by the output from said pulse generator which totalizes the pulses which represents the equivalent hours of operation of the component relative to the designed reference service life.
Claim 6
Dependent Claim
294 words
Apparatus for monitoring the service life of components of a thermal power plant by counting hours equivalent to those of actual operation of the component at a given correlated mechanical and thermal stress value comprising: a first thermo-responsive element which measures the temperature at a point on the surface of the component under examination, means connecting the output from said first thermo-responsive element to an electronic function generator through a first buffer amplifier, said function generator producing at its output a first signal representative of a stress for that temperature corresponding to a designed reference service life, a second thermo-responsive element which measures the temperature at a point internally of said component and which is counter-connected with said first thermo-responsive element so as to produce a direct measurement of the temperature difference between said points and which is representative of the thermal stress, means connecting the temperature difference output signal from said counter-connected first and second thermo-responsive elements to an electronic device through a second buffer amplifier, said device combining said temperature difference signal with a known mechanical stress factor to produce at its output a second signal, means for comparing said first and second signals to produce a signal corresponding to the difference therebetween, a pulse generator driven by said difference signal Δσ and which produces pulses at a repetition rate proportional to a base frequency f o when Δσ=0 and which produces pulses at a repetition rate proportional to ##EQU8## when Δσ is not equal to zero, wherein K represents the stress difference corresponding to one decade of service life, and a counter driven by the output from said pulse generator which totalizes the pulses which represents the equivalent hours of operation of the component relative to the designed reference service life.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-04-20 | 1979-10-20 | 1980-04-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-04-20 | 1983-10-20 | 1984-04-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-04-20 | 1987-10-20 | 1988-04-20 | $7700.00 | Window Closed / Lapsed |