US3926039A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Pulsed ultrasonic flaw detector
Assignee: Individual
•
Filing: 1973-06-07
•
Granted: 1975-12-16
•
Expires: 1993-06-07
Abstract
Abstract The present invention relates to a Pulsed ultrasonic flaw detector designed to determine the location, size and character of internal defects in materials. An operational amplifier of the flaw detector includes a current generator circuit coupled to a capacitor that forms a control signal. The current generator has a controlled internal resistance and employs AC positive feedback provided by one of the amplifier stages of an operational amplifier. The output stage of the operational amplifier is coupled to the amplifier of the reflected signal receiver via an AC negative feedback circuit employed in one or several stages of this amplifier.
Inventors
- 👤 Oleg Nikolaevich Zhukov
- 👤 Moisei Davidovich Medvinsky
- 👤 Vladimir Izidorovich Ryk
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 22:51
CPC Classifications
G; G01; G01N; G01N29/00; G01N29/36; G01N29/40; G01N2291/00; G01N2291/02; G01N2291/028; G01N2291/0289; Y; Y10; Y10S; Y10S73/00; Y10S73/90
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
196 words
A pulsed ultrasonic flaw detector for testing materials, comprising an ultrasonic oscillator; a receiver for signals reflected from the internal defects in the material under test; a first amplifier for said receiver, including at least one stage for amplifying the signals introduced from said receiver; an AC negative feedback circuit in said one amplifier stage; an operational amplifier having therein a current generator circuit and at least two stages, including an output stage; said operational amplifier being connected to said first amplifier via said negative feedback circuit; said generator circuit having a controllable internal resistance and having applied thereto AC positive feedback furnished by one of said stages of said operational amplifier; in the latter, a capacitor coupled to said generator circuit and to said one stage thereof, said capacitor forming a signal to control said first amplifier, thereby compensating for the effect of the depth, at which the defects occur, on the amplitude of the signals reflected therefrom; an indicator connected to said first amplifier; a synchronizer connected to said oscillator, to said operational amplifier and to said indicator, in controlling relation thereto; and means for quickly discharging said capacitor which forms the control signal.
Claim 2
Dependent Claim
196 words
A pulsed ultrasonic flaw detector for testing materials, comprising an ultrasonic oscillator; a receiver for signals reflected from the internal defects in the material under test; a first amplifier for said receiver, including at least one stage for amplifying the signals introduced from said receiver; an AC negative feedback circuit in said one amplifier stage; an operational amplifier having therein a current generator circuit and at least two stages, including an output stage; said operational amplifier being connected to said first amplifier via said negative feedback circuit; said generator circuit having a controllable internal resistance and having applied thereto AC positive feedback furnished by one of said stages of said operational amplifier; in the latter, a capacitor coupled to said generator circuit and to said one stage thereof, said capacitor forming a signal to control said first amplifier, thereby compensating for the effect of the depth, at which the defects occur, on the amplitude of the signals reflected therefrom; an indicator connected to said first amplifier; a synchronizer connected to said oscillator, to said operational amplifier and to said indicator, in controlling relation thereto; and means for quickly discharging said capacitor which forms the control signal.
Claim 3
Dependent Claim
60 words
The ultrasonic flaw detector as defined in claim 1, wherein said current generator circuit and said one stage in said operational amplifier include transistors; the collector of one of said transistors, in said generator circuit, and the base of another one of said transistors, in said one operational amplifier stage, being connected to said capacitor which forms the control signal.
Claim 4
Dependent Claim
34 words
The ultrasonic flaw detector as defined in claim 2, further comprising an adjustable resistor included in the emitter circuit of said one transistor, allowing to control the internal resistance of said current generator circuit.
Claim 5
Dependent Claim
34 words
The ultrasonic flaw detector as defined in claim 2, further comprising a potentiometer included in the collector circuit of said other transistor, allowing to control the positive feedback applied to said current generator circuit.
Claim 6
Dependent Claim
100 words
The ultrasonic flaw detector as defined in claim 1, wherein said output stage of the operational amplifier and said one stage of the amplifier include transistors; a resistor included in said negative feedback circuit, serving as a load in the emitter circuit of one of said transistors, in said one stage of the amplifier; the collector of another one of said transistors, in said output stage, being connected in parallel with said resistor; and another capacitor connected to the emitter of said other transistor; a potentiometer which connects the base of said other transistor to control said negative feedback circuit.
Claim 7
Dependent Claim
91 words
The ultrasonic flaw detector as defined in claim 1, wherein said one amplifier stage includes a first transistor; said output stage includes a field-effect transistor; further comprising another capacitor included in said negative feedback circuit; the base of said first transistor being connected to the source of said field-effect transistor via said other capacitor; the drain of said field-effect transistor beiNg coupled to the collector of said first transistor; and a potentiometer connecting the gate of said field-effect transistor to said one operational amplifier stage, to control said negative feedback circuit.
References Cited (Backward Citations)
US3690153A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-12-15 | 1979-06-16 | 1979-12-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-12-15 | 1983-06-16 | 1983-12-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-12-15 | 1987-06-16 | 1987-12-16 | $7700.00 | Window Closed / Lapsed |