Abstract: A pulsed magnetic procedure and apparatus for measuring wall thickness. It is especially applicable to pipelines. It includes pulsing a magnetic reluctance coil that is located close to the wall, and measuring the inductance of the pulsed coil. Also the distance of the coil from the wall is accurately determined so that the inductance is a measure of the wall thickness.Apparatus may include the combination of an ultrasonic transducer mounted fixed relative to the magnetic pulse coil and arranged so that ultrasonic energy pulses are directed toward the wall. In this manner reflected ultrasonic pulses will provide a measure of the distance. In addition, by proper angle thereof, ultrasonic pulses may also determine the presence of any anomaly.

Abstract: An apparatus and method for making wall thickness measurements. It is particularly applicable to pipeline use. It uses a pulse-echo acoustic arrangement with a single piezoelectric transducer sending and receiving acoustic signals from both faces. It has a pair of reflectors, one for each face of the transducer so that acoustic energy is directed both normal to the wall and at an angle in order to simultaneously measure the wall thickness and find any anomaly such as pitting or the like. For pipeline use there may be a plurality of instruments situated around the periphery of a unit to scan the walls as it travels through the pipeline.

Abstract: A method of marking a pipeline location eliminates ambiguity in case there are leaks near the location of a marker. It employs a marker that emits two separate frequencies that are modulated by a third frequency lower than either of the other two. Detection of the marker on a pipeline pig is done by separating the two frequencies and demodulating the third. Then by determining the coincidence of all three for a predetermined number of consecutive cycles of the third frequency, the marker location will be positively identified.

Abstract: An acoustic type of pipeline marker that has combined with it, as a unitary structure, an acoustic signal detector for determining whether the marker is operating. The detector is only energized when it is desired to check whether the marker is emitting the desired acoustic signals into the pipeline. The detector provides a visual signal.

Abstract: A system employing a plurality of electronic oscillators for generating test signals at spaced locations remote from a selection point. The oscillators are coupled to a gathering line for petroleum products, each being located adjacent to an acoustic detector coupled to the line for signaling the presence of a leak within its range. A digital selector which manually generates a given number of pulses is located at the selection point. There is a binary counter at each oscillator to receive the pulses. And, there is also a binary encoder at each oscillator to determine which one will be energized, depending upon the number of pulses generated by the selector.

Abstract: A method and system for improving the pulse-echo type of testing to determine wall thicknesses. It is particularly applicable to pipes. There is a pulse directed transversely to the wall so that reflections from the inner and outer surfaces will indicate the thickness, and another pulse is directed at an angle to the wall with time spacing. The angled pulse path permits penetration so that the presence of an undesirable type of discontinuity will cause an additional reflection which distinguishes this type of discontinuity.

Abstract: A pivoted pointer or stylus is mounted for actuation by reciprocatory plunger action. It has a stop associated with the plunger to hold the stylus locked in a neutral position until the plunger is actuated. The stylus has a cam action surface for cooperating with another part of the stop after the stop has moved to release the stylus. The cam action causes pivotal movement of the stylus to indicate an event.

Abstract: An ultrasonic transducer that employs a piezoelectric crystal which is made of lead metaniobate so that it has good sensitivity while also having a low Q. The transducer includes a backing support for one face of the crystal which provides damping of the acoustic energy being generated in the reverse direction. The backing support includes an epoxy resin with heavy metal objects moulded therein.