SU57896A1 - Device for measuring natural potential differences along pipelines - Google Patents

Description

The greatest damage to pipelines by corrosion is usually due to the so-called electrolytic corrosion, Korii, a. metal particles are carried away by currents flowing from the pipes into the ground (corrosion in the anode zones).

The most common method of determining such zones along oil pipelines is currently the method of measuring natural earth currents using the Schlumberge method. The essence of this method is reduced to simple measurements of potential differences across the surface of the earth along the pipeline. However, it is known that in addition to the currents flowing through the pipeline, there are many other sources of emf in the earth. (Effects of electrofiltration, diffusion, etc.). Sources of these create anomalies of the type of type. a) they cover vast areas, on the contrary, they are very narrowly localized. In either case, the anomalies caused by natural currents are not distinguishable from the positive anomalies created by currents emerging from the pipe. This is

the first source of unreliability of measurements by the Schlumberger method. Besides, at present all USSR oil pipelines must be subjected to cathodic protection. In this case, to design and implement monitoring and protection, it is necessary to know the distribution of the potential along the pipe itself. It is quite clear that the method of measuring natural earth currents in the form in which it was proposed by Schlumberger cannot provide an answer to this question. This is the second disadvantage of this method. In the Schlumberger method, it is difficult to distinguish narrowly localized outputs (point sources) from sources of a linear type of small length, etc.

The proposed invention aims at eliminating the aforementioned deficiencies, for the h & a measure of potential along the pipeline, made with the help of electrodes that are propelled inside the pipeline. For the e-voro, the device for measuring the potential is made, according to the invention, in the form of a projectile moving along the pipeline with the medium flowing inside and carrying the electrodes, a voltmeter and a recording device.

In this case, one electrode is mounted directly on the screen, and the second is connected with it by means of a cable and pressed against the surface of the pipe by a spring, and the rollers associated with it, pressed by a spring to the internal surface of the pipeline, are used to drive the recording device.

In addition, in order to realize the possibility of moving the projectile along the pipeline by the medium flowing inside it, the projectile body is provided with sealing rings.

The drawing shows a schematic of the proposed device inside the pipeline.

The device consists of an armature (1) connecting pipe, an armored connecting cable (2) and a spring contact (3). Cylinder 1 is a hollow body of much smaller diameter than the internal diameter of the pipeline. On it, a sealing ring 4 is fixed, which turns cylinder J into a piston moving under the pressure of oil flowing through the pipeline. An axis 6 is mounted inside the cylinder, on which two holders 6 with rollers 7 are seated freely at their ends. The holders 6 are provided with springs that press the rollers until they are tightly in contact with the inner wall of the pipeline. As the rollers rotate, the two 8 to 9 recording devices located inside the cylinder are set in motion. On one of them, a photosensitive paper is screwed up, gradually rewinding as the entire device moves along the pipeline to the second drum. Above the sealing ring there are two elastic metal rods 10, which are electrodes closed at one end of the winding of the frame mounted inside the cylinder / voltmeter (not shown in the drawing). The arrow of the voltmeter is located in close proximity to one of the drums 8 or 9 with paper and is equipped with

at its end is a recess in which the luminous composition of a constant action is placed.

In the lower part of the cylinder / there are tides P, which play the role of a load, orienting the device when moving in the vertical direction.

The clamp 3 consists of two spring-loaded contacts (electrodes) connected via an armored cable 2 to the second end of the winding of the millivoltmeter frame.

Such a device through an auxiliary branch with valves is introduced into the pipeline being investigated and moves along with the pumped oil from one station to another. Having removed it from the tube at the second station and into the paper from the drum and having rolled it, the operator obtains the potential gradient curve.

Before the first start-up of the device, the pipeline must be cleaned with a scraper.

The subject matter of the invention.

Claims (4)

1. A device for measuring natural potential differences along pipelines using electrodes pushed inside the pipeline, characterized in that they are made as a projectile, moved along the pipeline by medium flowing inside it and carrying electrodes, a voltmeter and a recording device. 2. The form of the device according to claim 1, characterized in that one electrode is mounted directly to the device, and the second is connected with it by means of a cable and is pulled to the surface of the pipeline by a spring. 3. The form of the device according to claim 1, characterized in that, in order to move the projectile along the pipeline by the medium flowing inside it, the housing is equipped with sealing rings. 4. The form of the device according to claim 1, characterized in that for; the recorder drive is applied associated with it, rollers 7, pressed against the internal surface of the pipeline by a spring. 4 in.