RU2445613C1 - Method to diagnose technical condition of pipelines and device for its realisation - Google Patents

Abstract

FIELD: construction.

SUBSTANCE: device to diagnose technical condition of a pipeline, comprising a source of magnetic field and a receiver to receive a signal installed outside the pipeline as capable of displacement, at the same time in the pipeline there is an additional source of magnetic field capable of displacement. Besides, the additional source of magnetic field capable of displacement is made of a toroid with a source of magnetic field filled with liquid or gas.

EFFECT: increased accuracy of pipeline defects detection.

4 cl, 5 dwg

Description

The invention relates to the field of construction and can be used to diagnose the technical condition of pipelines and other steel hollow structures.

A known method and device for diagnosing the technical condition of the pipeline, which consists in the fact that the ultrasound source is moved inside the pipeline and a signal is received by the receiver, which determines the defects of the pipeline (RF Patent No. 2149394 from 09/07/99).

The disadvantage of this method and device is the low accuracy of determining defects in the pipeline.

A known method for determining a defect in the pipeline and a device for its implementation. The method consists in the fact that a torus is rolled through a pipeline with a liquid or gas flow and the flow pressure is measured behind the torus. By changing the pressure in the stream, the location of the fistula is determined. The device is made of a torus, sensors for measuring pressure in the flow and the distance that the torus has passed (RF Patent No. 2164321 of March 16, 1999).

The disadvantage of these method and device is that they can only be used to determine the location of fistulas.

A known method and device for diagnosing the technical condition of the pipeline by magnetic tomography, which consists in the fact that on the surface of the Earth parallel to the pipeline move the magnetic field source with a mechanism for determining changes in the magnetic field, which determine the defects in the wall of the pipeline. The device consists of a portable source of magnetic field and a signal receiver (Patents of the Russian Federation No. 2132904, No. 2290765 from 12/27/2001, No. 2042946).

The disadvantage of this method and device is the lack of sensitivity.

The objective of the invention is to increase the sensitivity of the diagnosis of pipelines.

The problem is solved by the combined use of a group of inventions.

An additional movement of the magnetic field source inside the pipeline with simultaneous mechanical force acting on the pipe wall makes it possible to increase sensitivity and find smaller defects.

The movement of the source of the magnetic field and the mechanism of action on the wall of the pipeline by the flow of liquid or gas by rolling the torus simplifies the method and design of the device.

Filling the torus with a fluid agent increases sensitivity.

Installing a magnetic field source in the pipeline with the ability to move it increases the sensitivity.

The implementation of the magnetic field source and the mechanism of action on the pipe wall in the form of a torus simplifies the design.

The implementation of the source of the magnetic field from a magnetic fluid or permanent magnets increases the sensitivity.

Making the diameter of the torus larger than the diameter of the pipe in which it rolls, improves sensitivity.

The drawings show:

figure 1 - device in the pipeline;

figure 2 - the device of the torus filled with magnetic fluid;

figure 3 - torus with magnets;

figure 4 - a torus with magnets placed in a magnetic fluid;

figure 5 - diagram of the device.

The device depicted in figure 1, is made of a pipeline 1 in which a torus 2 is installed, with a source 3 of a magnetic field.

The device shown in FIG. 2 is made of a torus 2, which is filled with magnetic fluid 4. In this case, the magnetic field source 3 is made of magnetic fluid 4.

The device shown in Fig. 3 is made of a torus 2, in which endless ribbons 5 are fixed with permanent magnets 6 mounted on them. Top 2 is filled with a fluid agent 7 (liquid, gas).

The device depicted in figure 4 is made of a torus 2 filled with magnetic fluid 4. On the inner surface of the torus 2 endless tapes 5 with permanent magnets 6 are fixed.

The device depicted in figure 5, is made of a torus 2 with a source 3 of a magnetic field. A torus 2 is installed in the pipeline 1. Above the pipeline 1 there is an autonomous receiver 8 for creating and receiving a magnetic field, for example, a mechanism for diagnosing the pipeline 1 by magnetic tomography.

The device shown in figures 1-5, operates as follows. In the pipeline 1, a torus 2 with a magnetic field source 3 is synchronously moved, and an autonomous receiver 8 for creating and receiving a magnetic field is moved over the pipe 1.

When the torus 2 rolls in the pipeline, the source of the magnetic field 3 creates a rotating magnetic field that passes through the steel wall of the pipeline 1. Defects in the wall of the pipeline distort the magnetic field.

Colloidal particles of a ferro or ferrimagnet have a constant magnetic moment. An external magnetic field orders the direction of the magnetic moments, which leads to the appearance of macroscopic magnetization. There are two mechanisms for disorienting the magnetic moments of colloidal particles. In a solid uniaxial particle, a thermal “transfer” of the magnetic moment occurs between two opposite directions of the axis of easy magnetization of the crystal. The second mechanism is due to Brownian (thermal) rotation of particles relative to the liquid base.

In medium-sized magnetic fields, thermal motion prevents the alignment of magnetic moments along the field. In a very strong field, all magnetic moments are oriented by the field, and the magnetization reaches a saturation state. In equilibrium, the magnetization of a liquid depends on the volume concentration of the magnetic material, the magnitude of the magnetic moment of the particle, the applied field, and the energy of the disordering thermal motion.

It is established that the rotation of the torus practically eliminates the energy of disordering thermal motion.

The concentration of the solid phase near the torus shell increases by almost an order of magnitude. This concentration depends on the speed of rotation of the torus.

In magnetic fluids, there is a certain polydispersity of the solid phase. Magnetization curves show a strong influence of the particle size of magnetite on the magnetic susceptibility and magnetic moment. The so-called magnetogranulometric method for determining the size of small magnetic particles is based on a comparison of experimental curves.

With the rotation of the torus, this effect practically disappears; small particles are located between large particles.

However, there is an optimal size of magnetic particles. This effective magnetite particle diameter was 11.7 nm.

The ratio of magnetization and density of the solid phase content has a significant effect on the magnetic properties of the liquid.

During rotation of the torus, magnetic particles are oriented so that they significantly increase the real moment of magnetite particles.

It was found that a sharp increase in the concentration of magnetite particles in the region of the shell practically does not change the total viscosity of the entire volume of magnetic fluid. Therefore, the force required to roll the torus remains virtually unchanged.

The torus provides the aggregation of magnetite particles, which form an additional shell constructed of aggregated particles.

When the torus rotates, the magnetic fluid becomes non-isotropic: the orientation of individual magnetic moments and, therefore, the particles themselves occurs if there is a connection between the moment of the particle and its crystallographic axis. This relationship is caused by intrinsic particle anisotropy, which is due to crystallographic magnetic anisotropy and particle non-sphericity. Assuming the first main reason, we recall that the energy of magnetic anisotropy is characterized by the work that must be expended in order to change the selected direction of the magnetic moment along the axis of easy magnetization. The degree of coupling of the magnetic moment with the axis, therefore, is determined by the energy of magnetic anisotropy in comparison with the energy of thermal motion.

The appearance of ordered aggregates in a fluid with increasing concentration leads to a deviation of the linear dependence of magnetization.

This ensures that a stronger magnetic field is created in the pipe wall, which allows smaller defects to be detected.

The detection of defects is also facilitated by the pressure of the torus on the wall of the pipeline 1, since the deformation of the pipeline from the internal load strongly distorts the magnetic field.

The appearance of aggregates of magnetic particles in a magnetic fluid, as well as an increase in the diameter of monodisperse particles, should qualitatively affect the magnetization curve.

Example

Diagnostics of the steel pipeline supplying drinking water. The diameter of the pipeline is 800 mm, the wall thickness is 14 mm.

Deposits of 50-100 mm thick formed in the pipeline. The length of the pipeline is 12 km. Initially, the pipeline was cleaned of deposits by treatment devices according to patent RU 2358186.

During cleaning, a chemical coating was formed on the surface of the pipeline by feeding it into water, which was used to purify sodium polyphosphate at a dose of 100 mg / L according to P ₂ O ₅ . After cleaning, a torus was installed in pipeline 1, the diameter of which was 10 mm larger than the inner diameter of pipeline 1, and the torus length was 1500 mm. A magnetic fluid was pumped into torus 2 under a pressure of 0.4 MPa.

Torus 2 was installed in pipeline 1. A compressed air pressure of 0.2 MPa was moved to the end of the pipeline at a speed of 4 kilometers per hour.

Simultaneously above the pipeline, a tomograph was produced by Scientific-Technical Center Transkor-K LLC. The tomograph was moved manually.

The following pipeline defects were identified:

- two through fistulas ⌀4 mm;

- ulcers 1-5 mm deep were revealed along the entire length of the pipeline.

It was decided to apply a layer of fiber-reinforced concrete 4 mm thick on the inner surface of the pipeline along the entire length of the pipeline.

Using the invention improves the accuracy of determining pipeline defects.

Claims (4)

1. A device for diagnosing the technical condition of the pipeline, including a source of magnetic field and a receiver for receiving a signal located outside the pipeline with the possibility of their movement, while the pipeline has an additional source of magnetic field with the possibility of its movement, characterized in that the additional source of magnetic field with the possibility its movement is made from a torus with a magnetic field source that is filled with liquid or gas. 2. The device according to claim 1, characterized in that the torus is filled with magnetic fluid. 3. The device according to claim 1, characterized in that endless ribbons with permanent magnets mounted on them are fixed inside the torus. 4. The device according to claim 1, characterized in that the torus is made of a larger diameter than the inner diameter of the pipeline through which it moves.

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