RU2293981C1 - Electromagnetic probe for in-tube flaw detection of tube wall material - Google Patents

Abstract

FIELD: in-tube flaw detection of tube wall material.

SUBSTANCE: electromagnetic probe for in-tube flaw detection of tube wall material contains onboard power source, connected serially: fixed frequency generator, commutator, matrix panoramic inductive vortex-current transformer, consisting of n superimposed inductance coils, and detector, and also rope with communication cable, while introduced to probe is ribbon of elastic material, provided with fringe on one end, while n superimposed inductance coils of matrix transformer are positioned in cross-section of hollow cylindrical frame with even step along circle of its external generating surface, frame being made of dielectric material, while external working surfaces of superimposed coils are made flush with upper generatrix cylindrical surface of frame and ribbon is fastened to these surfaces of frame and coils with its fringe directed outside, making the probe look like a wire brush, fringe is made with even height, elements of blocks of generator, commutator and detector are made on electronic board, positioned in the hollow of cylindrical frame, which is filled with sealing compound, for power source a separate compartment is provided in the hollow of frame, rope is rigidly connected to end of frame, and communication cable is connected to output of detector.

EFFECT: decreased dimensions of probe, production of stable signal at probe output, and also realization of continuous in-tube flaw detection of tube wall of both ferromagnetic and non ferromagnetic material.

2 dwg

Description

The invention relates to a control and measuring technique, namely, in-line inspection of the material of the wall of the drill and casing pipes of the bottom holes, and can be used in the production of such pipes.

Known self-propelled installations of the type "Crowler" containing a panoramic radiation emitter, battery, generator, detector block, electric drive, etc. [Prospectus of the company JME (England) Crowlers, Representative office of the company in Russia LLC "Russian-British Enterprise" Spectrum NTD ", prospectus attached].

The disadvantages of the known installations are the high environmental hazard for staff and the environment, since the used isotopes emit a radioactive field, the complexity and not the safety of the service, it is possible to control only welds of large diameter pipes.

Known electromagnetic probes containing matrix inductance-eddy current converters, the inductors of which are made in the form of groups oriented to each other perpendicularly [see A.S. USSR No. 1350594, 1987, BI No. 41] or oriented plane-parallel to the object under study [Patent No. 2172268, 2001, BI No. 23].

The functionality of these probes is limited in that they control a flat surface of extended dimensions and are not suitable for use in flaw detection of medium-diameter pipes, such as drill and casing pipes. The need for quality control of the material of such pipes in their manufacture is due to the fact that the wells can be both vertical and inclined, therefore, during the operation of pipe assemblies, large bending loads arise, which can lead to pipe rupture at the site of its defect, undetected due to the lack of operation control.

The closest technical solution to the proposed one is panoramic magnetic “Crawler”, containing a generator, a block of detectors, and controls for “Crowler” and information processing [V.F. Muzhitsky, V.P. Kurozaev, A.S. Bakunov, etc. New magnetic and eddy current means of non-destructive testing and technical diagnostics // Control. Diagnostics. - 1999. No. 5. - C.5-9].

The disadvantage of this "Crowler" is the limited functionality of the control welds on pipes of large diameter of a ferromagnetic material.

The essence of the invention lies in the fact that in an electromagnetic probe for in-line inspection of material of a pipe wall material containing an on-board power supply, a fixed frequency generator, a commutator, a panoramic panoramic inductor-eddy current converter consisting of n overhead inductance coils, and a detector, as well as a cable with a communication cable, a ribbon of elastic material is introduced, provided with a fringe on one of the sides, and n overhead inductors of the matrix transducer are placed in a cross section of a hollow cylindrical frame with equal pitch around the circumference of its outer forming surface, the frame is made of dielectric material, while the outer working surfaces of the overlay coils are flush with the forming outer cylindrical surface of the frame and a fringed ribbon is fixed on their surface, giving the probe the appearance of a household "ruff", the fringe is made of the same height, the elements of the blocks of the generator, switch and detector are made on a printed circuit board located in the cavity of qilin Drum frame, which is filled with a sealing compound, a separate compartment is provided for the battery in the cavity of the frame, the cable is rigidly attached to the end of the frame of the probe, and the communication cable is connected to the output of the detector.

The technical advantage of the proposed probe is its small size due to the derivation of secondary signal conversion means from its design, but obtaining a stable signal at the probe output, as well as continuous (throughout the body) in-line flaw detection of the pipe wall of both ferromagnetic and non-ferromagnetic material when the probe moves inside pipes.

Figure 1 shows the placement of the probe in the pipe in the context; figure 2 is a cross section along aa of figure 1.

The probe contains a power source 1, a variable frequency generator 2, a switch 3, a panoramic panoramic inductive-eddy current transducer with n inductors 4 inductance placed in the cross section of the hollow cylindrical frame 5 on its outer surface, detector 6. Technologically, in the body of the frame cross section 5 s with an equal step around the circumference of the section, holes are made in which the inductors 4 are embedded, so that their working surface is flush with the outer surface of the frame 5. Coils 4 in the holes of the frame 5 fixed by means of, for example, glue. The frame is made of rigid dielectric material. Inductors 4 are included in the oscillatory circuits and tuned to resonance to increase the metrological characteristics of the matrix Converter. The word panoramic should be understood as control coverage of the full cross section of the pipe.

On the outer surfaces of the coils 4 and the frame 5, a film 7 is attached with a fringe 8, for example, with glue facing the outside and having the same height. The film 7 with a fringe 8 is made of a dielectric, elastic and wear-resistant material such as lavsan and gives the probe the appearance of a household (economic) ruff. Such a film can be performed, for example, in the form of a stocking. Inside the cavity of the frame there is a compartment for accommodating the power source 1, which can be a battery, in the remaining cavity there is a printed circuit board 9 on which the elements of the generator 2, switch 3 and detector 6 are installed.

Thickness, as well as the chemical composition of the tested pipe, are assumed to be quasi-identical, respectively. The input of the generator 2 is connected to the output of the power source 1, and the output to the input of the switch 3. N outputs of the switch 3 are connected to n inputs of the matrix Converter, the output of which is connected to the input of the detector 6.

Generator 2 is designed to generate a voltage of a fixed variable frequency, the value of which is assigned based on the thickness of the pipe wall, which must be completely translucent, and the chemical composition of its material. For an approximate estimate of the penetration depth of the electromagnetic field of the overhead inductive-eddy current transducer into the control object, you can use the plane wave penetration formula δ (m):

where ω is the circular frequency of the drive excitation current; μ - absolute magnetic permeability, GN / m; σ is the specific electrical conductivity of the material of the test object, S / m

The switch 3 performs the function of switching the inputs of the converter with a frequency an order of magnitude and lower than the frequency of the generator 2 in order to exclude the mutual influence of n inductors 4. The detector 6 is designed to rectify the analog variable information signal into a constant signal to increase its noise immunity during transmission and the possibility of transmitting it over a long distance.

The cable 10 is mounted on one of the ends of the frame 5 of the probe and is designed to pull it inside the pipe by means of an electric drive mounted outside the pipe (not shown). The speed of pulling does not exceed 20 ... 30 m per minute. Since the probe is covered with a fringe of the same height, when pulling it in the pipe cavity, the gap between the inner surface of the pipe and the outer surface of the frame with coils 4 is always constant. Since individual pipes do not exceed the length of a railway carriage (12 m), the cable length can also be selected within 13 m. An electric cable 11 is connected to the output of the detector 6 to transmit an information signal, if necessary, to a secondary converter (also not shown) for further his analysis.

The work of the probe. The test pipe is mounted on a slipway and secured. A probe is placed at one of the ends of the pipe, while the cable and the connection cable of the probe are pulled through the cavity of the pipe to its opposite end. After warming up the probe elements, the power source includes a generator 2, which excites through the switch 3 alternately with the switching frequency the oscillatory circuits n of the inductance coils 4 of the matrix converter.

In accordance with this, each inductor 4 creates in the local zone a so-called primary electromagnetic field, which, penetrating the wall material of a ferromagnetic or non-ferromagnetic pipe, induces eddy currents in it. These currents excite the secondary electromagnetic field, which interacts with the primary field. According to the degree of interaction of the primary and secondary electromagnetic fields, the electrical signal at the output of this oscillating circuit changes. This signal is rectified in the detector 6 and enters the communication cable 11. By changing the rectified signal, the structure of the material (voids, foreign inclusions, etc.) is judged. If necessary, the signal is supplied to peripheral units for storing, recording and performing other functions.

The technical advantage of the proposed probe is its small size due to the derivation of secondary signal conversion means from its design, but the receipt of a stable signal at the probe output, as well as continuous (throughout the body) in-tube inspection of the pipe wall of both ferromagnetic and non-ferromagnetic material when the probe moves.

Claims (1)

An electromagnetic probe for in-pipe inspection of a pipe wall material, comprising an onboard power supply, a fixed frequency generator connected in series, a switch, a panoramic panoramic inductor-eddy current converter, consisting of n overhead inductance coils, and a detector, as well as a cable with a communication cable, characterized in that a ribbon of elastic material is introduced into the probe, provided on one side with a fringe, an overhead inductance coils of the matrix transducer are placed in cross section the hollow cylindrical frame with equal pitch around the circumference of its outer forming surface, the frame is made of dielectric material, while the outer working surfaces of the overlay coils are flush with the forming external cylindrical surface of the frame and a fringed tape is fixed on these surfaces of the frame and coils, giving the probe a look household ruff, the fringe is made of the same height, the elements of the generator blocks, the switch and the detector are made on a printed circuit board located in the cavity core frame, which is filled with a sealing compound, a separate compartment is provided for the power supply in the cavity of the frame, the cable is rigidly attached to the end of the frame, and the communication cable is connected to the output of the detector.

Images