Measuring and testing – Vibration – By mechanical waves
Patent
1985-11-22
1987-05-05
Levy, Stewart J.
Measuring and testing
Vibration
By mechanical waves
G01N 2904
Patent
active
046622241
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
The invention relates to the inspection of the rails of railroad tracks, and more particularly to a process for the automatic recognition of discontinuities or irregularities and especially the fished joints of the rails of railroad tracks, as well as to a device for the implementation of such a process.
The stresses and dynamic overloads to which the track is subjected cause the development of internal faults in the rail, such as oval flaws, horizontal, transverse or longitudinal cracks, star-shaped cracks, etc.
It is important to be able to detect these faults on the track using a non-destructive method, in order to be able to change defective sections of rail in time while distinguishing as far as possible between faults and joints or other discontinuities that can occur in the rails.
The most widely used method of non-destructive testing of the internal state of rails on the track is the sounding of the rail by ultrasonics. This technique consists in placing in contact with the rail head transmitting, receiving or transmitting-receiving probes, the orientation of which is adapted to the type of fault being looked for.
In general, light instruments employed by an operator or heavy instruments carried in rail cars are used.
In the first case, the operator sounds one or two lines of rail simultaneously using ultrasonic instruments adapted to this technique. A probe is placed in contact with the running surface of each rail. The operator advances slowly, at a speed of about 3 km/h, and checks all the ultrasonic detections on the screen of the instrument. He therefore has to analyse the results displayed by the instrument and correlate them with the rail. In fact not every ultrasonic detection is necessarily associated with an internal fault. For example the fishing holes in the rails appear very clearly on the instrument but must not be considered as faults. Another example is that relating to the detection of the ends of rails when these are fished. The rail, in this case, behaves like a rail with a vertical break through its full height. In this case the ultrasonic instrument indicates sounding anomalies. The operator can easily see the difference between a broken rail and the end of a rail when it is fished. He interprets the results of the ultrasonic sounding in order to sort certain data, helped by the fact that he can see the rail.
On the other hand, in the second case, when the detection equipment is carried in a sounding rail car, this analysis is made very difficult because of the speed at which the machine moves (which can be of the order of 30 to 50 km/h). It became necessary in this case to develop a process which enables the real faults in the rail to be distinguished from all the detections made by the instruments in order to sort the results automatically.
SUMMARY OF THE INVENTION
The purpose of the present invention is to enable the automatic detection and distinguishing of fished joints from the cracks present in the rails of railroad tracks by means of a detection equipment carried in a vehicle able to move at a relatively high speed.
The invention therefore relates to a process for the automatic detection and recognition of discontinuities and especially the fished joints of the rails of railroad tracks, on the track and continuously, by means of beams of ultrasonic waves, enabling the fished joints to be distinguished from the faults in the rail by carrying out an automatic sorting of the detection signals.
The invention also relates to a device for the implementation of such a process, able to be used on the track at relatively high speeds, in the order of 30 to 50 km/h.
More particularly, the process according to the invention enables the detection of any discontinuity or irregularity, and the automatic distinction between a fished joint connecting two rails, a welded and cracked joint, and a rail having a known fished fault.
The process according to the present invention, for the automatic recognition and detection of discontinuities and especially of
REFERENCES:
patent: 2893239 (1959-07-01), Renaut
patent: 4457178 (1984-07-01), Turbe et al.
patent: 4487071 (1984-12-01), Pagano et al.
patent: 4594897 (1986-06-01), Bantz
Chapman, Jr. John E.
Levy Stewart J.
Matix Industries
Societe Nationale Des Chemins De Fer Francais
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