Abstract: What is claimed is an inspection device for in-tube monitoring of main pipelines by the method of ultrasonic wall thickness metering realized in a device traveling inside the pipeline and performing measurements, acquisition of measurement data and their interpretation. The device comprises a probing pulse generator, an ultrasonic transducer, an amplifier, a comparator with an analog input, a digital timer, a processor and a data storage module, and a controlled reference voltage source connected in series. The output of said reference voltage source is connected to the reference voltage input of the comparator, said reference voltage source being capable of setting at least two different voltages at its output.

Abstract: The claimed method of in-tube inspection of a pipeline is effected by passing through the pipeline an inspection pig carrying monitoring transducers responsive to the diagnostic parameters of the pipeline, means for measuring, processing and storage of the measurements data by periodic interrogation of the monitoring transducers during the travel of the inspection pig and processing and storage of the measurement data. The method is characterized in that during the travel of the pig with a period not less than the cycle time of the monitoring transducers the velocity of the inspection pig is determined, and the cycle time of the monitoring transducers is set as a function of at least two values of the pig velocity determined during its travel. The period of determining the inspection pig velocity makes 200-2000 cycles of interrogation of the monitoring transducers. The cycle of interrogation of the monitoring transducers is given a value from a number of discrete values in a series of at least 3.

Abstract: A method of in-tube ultrasonic inspection of pipelines is carried out by passing inside the pipeline a scanning pig, emitting ultrasonic probing pulses towards the pipe wall and receiving the reflected ultrasonic pulses. The received pulses are amplified using an amplification factor which is increased depending on the time elapsed from the moment of emitting the probing pulse. The threshold values of the pulse amplitudes are also varied depending on time. Digital values of the pulse amplitudes and the time elapsed from the moment of emitting the probing pulse and corresponding to each value of the amplitude are obtained. The method allows for compensation for the effect of ultrasound attenuation in the material on the amplitudes of the reflected pulses and, in this manner, to increase the accuracy of determining the geometrical parameters of the flaws, a probability of their detection and efficiency of estimation of their danger.

Abstract: What is claimed is an inspection device for in-tube monitoring of main pipelines by the method of ultrasonic wall thickness metering realized in a device traveling inside the pipeline and performing measurements, acquisition of measurement data and their interpretation. The device comprises a probing pulse generator, an ultrasonic transducer, an amplifier, a comparator with an analog input, a digital timer, a processor and a data storage module, and a controlled reference voltage source connected in series. The output of said reference voltage source is connected to the reference voltage input of the comparator, said reference voltage source being capable of setting at least two different voltages at its output.

Abstract: The claimed method of in-tube inspection of a pipeline is effected by passing through the pipeline an inspection pig carrying monitoring transducers responsive to the diagnostic parameters of the pipeline, means for measuring, processing and storage of the measurements data by periodic interrogation of the monitoring transducers during the travel of the inspection pig and processing and storage of the measurement data. The method is characterized in that during the travel of the pig with a period not less than the cycle time of the monitoring transducers the velocity of the inspection pig is determined, and the cycle time of the monitoring transducers is set as a function of at least two values of the pig velocity determined during its travel. The period of determining the inspection pig velocity makes 200-2000 cycles of interrogation of the monitoring transducers. The cycle of interrogation of the monitoring transducers is given a value from a number of discrete values in a series of at least 3.

Abstract: The method for preparing cross-linked vinylaromatic polymers containing nitro groups having the general formula ##STR1## where R' is H, NO.sub.2, COOH, SO.sub.3 H, P(O)(OH).sub.2, or P(O)H(OH), m is from 60 to 99 and n is from 40 to 1, consists in treatment of the starting cross-linked polymers having the general formula ##STR2## where R is H, COOH, SO.sub.3 H, P(O)(OH).sub.2, or P(O)(OH), m is from 60 to 99 and n is from 40 to 1, with a mixture of an alkali metal nitrate and an acid agent, at a temperature from -5.degree. to 95.degree. C. The quantity of the alkali metal nitrate in the nitrating mixture is from 0.1 to 8 moles per mole of the starting cross-linked polymer.The method provides conditions for preparing cross-linked vinylaromatic polymers, containing nitro groups, having higher mechanical strength, high osmotic stability, and their volume in an ion-exchange column changes insignificantly as acid media are changed for alkaline, and vice versa.