US3901071A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Ultrasonic thickness gauge
Assignee: LFE Corp
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Filing: 1973-09-25
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Granted: 1975-08-26
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Expires: 1993-09-25
Abstract
Abstract Ultrasonic probes are positioned around the circumference of a pipe to monitor the pipe thickness by the time interval between echoes from the outer and inner surfaces of the pipe. A multiplexing system operates the probes sequentially and a signal averaging circuit provides a signal indicative of the average pipe thickness which may be used in a control loop to maintain constant average pipe thickness in a pipe extrusion system.
Inventors
- 👤 Earl N Hansen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 06:01
CPC Classifications
G; G01; G01B; G01B17/00; G01B17/02; Y; Y10; Y10S; Y10S73/00; Y10S73/901
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
183 words
Gauging apparatus for measuring material thickness ultrasonically comprising: a. a plurality of at least three ultrasonic probes; b. a like plurality of pulsers connected to excite the respective ones of said probes; c. a single receiviNg channel connected to the mixed output of said probes for receiving the echoes from all of said probes; d. a single echo separator connected to the output of said receiving channel for selecting front and back interface echoes; e. a separation converter connected to the output of said echo separator for converting the time lapses between said front and back interface echoes to an analog voltage; f. an averager with input connections representative of respective ones of said plurality of probes connected to the output of said separation converter for averaging the analog voltages derived from the echo separations of at least three of said plurality of ultrasonic probes; g. multiplexing means for sequentially exciting said probes and sequentially transferring said analog voltages to the input of said averager; and h. single display means for indicating the average thickness of a material responsive to said analog voltages.
Claim 2
Dependent Claim
183 words
Gauging apparatus for measuring material thickness ultrasonically comprising: a. a plurality of at least three ultrasonic probes; b. a like plurality of pulsers connected to excite the respective ones of said probes; c. a single receiviNg channel connected to the mixed output of said probes for receiving the echoes from all of said probes; d. a single echo separator connected to the output of said receiving channel for selecting front and back interface echoes; e. a separation converter connected to the output of said echo separator for converting the time lapses between said front and back interface echoes to an analog voltage; f. an averager with input connections representative of respective ones of said plurality of probes connected to the output of said separation converter for averaging the analog voltages derived from the echo separations of at least three of said plurality of ultrasonic probes; g. multiplexing means for sequentially exciting said probes and sequentially transferring said analog voltages to the input of said averager; and h. single display means for indicating the average thickness of a material responsive to said analog voltages.
Claim 3
Dependent Claim
63 words
Gauging apparatus according to claim 1 wherein said receiving channel is provided with first and second signal outputs one of which may be inverted with respect to the other and said echo separator comprises detection means connected to said first signal output for detecting a front interface echo and detection means connected to said second signal output for detecting a back interface echo.
Claim 4
Dependent Claim
30 words
Gauging apparatus according to claim 1 wherein said separation converter comprises a ramp generator and means to initiate and terminate generation of a voltage ramp responsive to said echo separator.
Claim 5
Dependent Claim
47 words
Apparatus according to claim 1 in which said multiplexing means comprises a register having at least two sequentially-activated output terminals coupled to each of said pulsers only one of which terminals is connected to enable transfer of an analog voltage to the respective input of said averager.
Claim 6
Dependent Claim
26 words
Apparatus according to claim 1 wherein said display means is a digital display and further comprising an alarm to indicate deviations in excess of tolerance limits.
Claim 7
Dependent Claim
95 words
An ultrasonic thickness gauge comprising: a. a plurality of ultrasonic probes; b. means to pulse said probes; c. a single automatic gain controlled receiver for amplifying echoes received by all of said probes; d. means to detect the time intervals between received echoes from the respective probes; e. means to convert said time intervals into respective analog voltages; f. means to average said respective analog voltages; and, g. multiplexing means for sequencing the pulsing of said probes and simultaneously coupling the output of said means to convert to sequential inputs of said means to average.
Claim 8
Dependent Claim
95 words
An ultrasonic thickness gauge comprising: a. a plurality of ultrasonic probes; b. means to pulse said probes; c. a single automatic gain controlled receiver for amplifying echoes received by all of said probes; d. means to detect the time intervals between received echoes from the respective probes; e. means to convert said time intervals into respective analog voltages; f. means to average said respective analog voltages; and, g. multiplexing means for sequencing the pulsing of said probes and simultaneously coupling the output of said means to convert to sequential inputs of said means to average.
Claim 9
Dependent Claim
70 words
An ultrasonic thickness gauge according to claim 6 wherein said multiplexing means has an output register with two consecutive counting terminals connected to enable pulsing of a respective probe during two consecutive counts and with only the second of said counting terminals connected to enable the output of said means to convert, whereby the gain of said receiver becomes stabilized before an output is applied to said means to average.
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) | 1978-08-25 | 1979-02-24 | 1979-08-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-08-25 | 1983-02-24 | 1983-08-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-08-25 | 1987-02-24 | 1987-08-26 | $7700.00 | Window Closed / Lapsed |