Flaw detection system for railroad rails and the like

• US 4,487,071 A
• Filed: 09/22/1982
• Issued: 12/11/1984
• Est. Priority Date: 09/22/1982
• Status: Expired due to Term

• Current Assignee: Dapco Industries, Inc. (Westinghouse Air Brake Technologies Corporation)
• Original Assignee: Dapco Industries, Inc. (Westinghouse Air Brake Technologies Corporation)
• Inventors: Pagano, Dominick A., Morris, Kevin S.
• Primary Examiner(s): Gill, James J.
• Application Number:
  US06/421,472
• Time in Patent Office: 811 Days
• Field of Search: 73/609, 73/610, 73/611, 73/612, 73/615, 73/625, 73/631, 73/636
• US Class Current: 73/612
• CPC Class Codes: G01N 2291/0421 Longitudinal waves
• CPC Class Codes: G01N 2291/0422 Shear waves, transverse waves, horizontally polarised waves
• CPC Class Codes: G01N 2291/044 Internal reflections (echoes), e.g. on walls or defects
• CPC Class Codes: G01N 2291/2623 Rails; Railroads
• CPC Class Codes: G01N 2291/267 Welds
• CPC Class Codes: G01N 29/07 by measuring propagation velocity or propagation time of acoustic waves
• CPC Class Codes: G01N 29/2493 Wheel shaped probes
• CPC Class Codes: G01N 29/34 Generating the ultrasonic, sonic or infrasonic waves , e.g. electronic circuits specially adapted therefor
• CPC Class Codes: G01N 29/40 by amplitude filtering, e.g. by applying a threshold or by gain control

Abstract

Rail testing apparatus, particularly useful at the point of manufacture, for detecting flaws in railroad rails. A number of transducers transmit ultrasonic sound waves into a rail under test and receive the associated echo signals. The apparatus advantageously divides the rail into a plurality of measured rail segments and the amount of amplification applied to the associated echo signals may be varied over each rail segment, thus providing the ability to selectively increase or decrease the sensitivity of the testing apparatus. The amplified echo signals are selectively applied to detection apparatus with a positive and negative gating scheme to increase system accuracy and reliability.

Claims

1. Apparatus for detecting flaws in a railroad rail, the apparatus comprising;

means for transmitting ultrasonic signals into the railroad rail and for receiving associated echo signals from within the railroad rail;

distance measuring means for measuring the length of the railroad rail;

micro-processor means for dividing the railroad rail into a plurality of rail segments, said micro-processor means being responsive to operator-supplied data and to said distance measuring means for determining a length of each of said rail segments;

means for selectably applying predetermined amounts amplification to said associated echo signals received from within each of said plurality of rail segments; and

means responsive to said selectably amplified echo signals for providing indications of flaws within the railroad rail.

2. Apparatus in accordance with claim 1 wherein there is further included means for selectively applying said amplified echo signals from said supplying means to said providing means.

3. Apparatus in accordance with claim 2 wherein said selectively applying means includes positive gating means and negative gating means, said positive gating means for applying unexpected echo signals to said providing means and said negative gating means for applying expected echo signals to said providing means.

4. Apparatus in accordance with claim 3 wherein said providing means includes means responsive to the presence of unexpected echo signals for generating a signal indicative of a flaw within the railroad rail and means responsive to the absence of an expected echo signal for generating a signal indicative of signal loss from the railroad rail.

5. Apparatus in accordance with claim 1 wherein said micro-processor means further includes means responsive to operator supplied input data for setting the amount of amplification provided to said associated echo signals for each of said plurality of measured rail segments.

6. Apparatus for detecting flaws in a railroad rail, the apparatus comprising;

means for transmitting ultrasonic signals into the railroad rail and for receiving associated echo signals reflected from within the railroad rail;

distance measuring means for measuring the length of the railroad rail;

micro-processor means responsive to operator provided input data and to said distance measuring means for dividing the railroad rail into a plurality of predetermined measured rail segments and for applying predeterminable amounts of amplification to said associated echo signals received from said predetermined measured rail segments of the railroad rail;

means responsive to said amplified echo signals for providing indications for flaws within the railroad rail; and

means for selectively transferring said amplified echo signals from said supplying means to said providing means.

7. Apparatus in accordance with claim 6 wherein said selectively transferring means includes positive gating means and negative gating means, said positive gating means for applying unexpected echo signals to said providing means and said negative gating means for applying expected echo signals to said providing means,

8. Apparatus in accordance with claim 7 wherein said providing means includes means responsive to the presence of unexpected echo signals for generating a signal indicative of a flaw within the railroad rail and means responsive to the absence of expected echo signals for generating a signal indicative of signal loss from the railroad rail.