SU815643A1 - Method checking current distribution in an underground pipe line - Google Patents

Description

one

The invention relates to electrical measuring equipment and is intended for use in solving the problem of detecting and localizing damage in large trunk pipelines. A known method for measuring current in an underground pipeline provides for a qualitative assessment of the current distribution in terms of the protective potential measured at the Drainage points and on the control and measurement columns, relative to the copper-sulphate reference electrode, and also on the total current of the cathodic station 1.

However, the known method is characterized by low measurement accuracy, since the final results largely depend on the correctness of the choice of the place to install the copper sulphate electrode compared to the pipeline axis, on the soil condition-I of the insulation coating of the pipeline, on the input resistance of the measuring device and on other difficult factors to consider.

The closest technical solution to the invention is a method of controlling the distribution of current in

underground pipeline based

on repeated measurement of the magnetic field strength of the current in the process of progress along the pipeline 2.

However, in the practical method of measuring the method, the magnetic field is measured by a magnetometer that is installed on the earth above the pipeline discretely with a task in steps. The magnitude of the magnetic field strength is dependent on the strength of the current in the pipeline, on its depth, on the location of the pipeline relative to adjacent underground mechanical structures, which is associated with large errors in the final results.

 The purpose of the invention is to improve the accuracy of control.

The goal is achieved by the fact that in the method of controlling the distribution of current in an underground pipeline, based on the repeated measurement and magnetic field strength in the process of moving along the pipeline, the magnetic field strength is measured near the internal wall of the pipeline; - at points spaced around the cross-sections, equal to the distance from the axis of the pipeline.

FIG. 1 shows a kostructive solution for the implementation of the proposed method {in FIG. 2 is a functional diagram implementing the method of the measuring device. The overall equipment layout (Fig. 1) provides for the location of the measuring device 1 in the centralizer 2 connected by a towing cable 3 to the treatment plant 4. To center the measuring device 1 in the pipeline 5, the wheels 6 are fixed to the centralizer 2. In the measuring device 1 (Fig 2) magnetically sensitive sensors 7, amplifiers 8, a registering device 9, a time stamp generator 10, a tape drive mechanism 11 are installed. Sensors 7 are located at a predetermined distance from the inner surface of the pipe circumferentially with equal intervals. The tape mechanism is synchronized with the speed of advancement of the measuring device 1 by means of a resolver 12 placed in the drive of one of the centralizer wheels, and the resolver receiver 13, on the shaft of which the tape recorder is mounted.

The current distribution is monitored as follows.

When the measuring device 1 advances along the pipeline 5, the magnetic field strength is measured by magnetically sensitive sensors 7. The signals from the outputs of sensors 7 through amplifiers 8 are fed to the input of the recording device 9. At the same time, pulses from the generator 10 of time stamps are supplied to the recording device 9. Synchronization of the tape-testing mechanism 11 with the speed of advancement of the measuring device 1 allows to obtain a complete picture of the distribution of the modulus of the magnetic field of the current along pipe-i wire 5 and to make a conclusion about the distribution of the controlled current itself.

The location of the magnetically sensitive sensors inside the pipeline reduces the effect of interference from neighboring communications on the measurement accuracy ..

In this connection, it is possible to detect very weak field distortions in the places of defects in the insulation coating of the pipeline. The continuous and high rate of advancement of the measuring device inside the pipeline creates prerequisites for improving the performance of the measurements.

Claims (2)

1. Kotik V..G. Cathode protection of pipelines. M., Nedra, 1964. 2. Scritsky P.P. Contactless 0 magnetometric measurement method currents on underground pipelines. Corrosion and protection in the petroleum industry, 1970, 1. W / 3 M s 1 Fm.2