SU1532806A1 - Device for monitoring the sectional area of steel ropes - Google Patents

Abstract

This invention relates to non-destructive testing. The purpose of the invention is to improve the accuracy and reduce the size of the device. For this, the magnetically sensitive elements 4 are placed symmetrically with respect to the longitudinal axis of the gap 2 between the permanent U-shaped magnets 1 at the outer surface of their middle part with the possibility of moving in the direction perpendicular to the axis of the gap 2. Installing the magnet 1 between element 4 and the cable 3 provides a significant increase sensitivity, since due to such an installation a magnetic bridge is formed, the magnetic flux of the magnetizing element is divided into flux through the rope and flux through the element. A small relative change in the magnetic flux through the cable leads to a significant change in the flux through the magnetically sensitive element. 1 hp ff, 1 ill.

Description

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the magnet 1 between the element 4 and the cable 3 provides a significant increase in sensitivity, since due to such an installation a magnetic bridge is formed, the magnetic flux of the magnetizing element is divided into the flow of

cut the rope and flow through the element. A small relative change in the magnetic flux through the rope leads to a significant change in the flux through the magnetosensitive element, t Cp. f-ly, 1 ill.

The invention relates to non-destructive testing and can be used to control changes in the cross-section f5 of steel ropes.

The purpose of the invention is to improve the accuracy by increasing the sensitivity of the magnetically sensitive element, eliminating the influence of the magnetic current of the magnetically sensitive element on the magnetization circuit and eliminating the influence of the rope (lay) geometry on the device and reducing the size of the device due to the operation of 25 in the optimal magnetic flux.

The drawing shows a diagram of the proposed device.

The device contains two U shaped magnets 1, facing each other with like poles forming a gap 2 for accommodating the controlled cable 3, and magnetically sensitive elements 4, made, for example, in the form of a coil with ferromagnetic core. The magnetically sensitive elements 4 are oriented with their sensitivity axis parallel to the longitudinal axis of the gap 2 and are installed symmetrically with respect to this axis at the outer surface of the middle part of the U-shaped magnets 1 with the ability to move in the direction perpendicular to the axis of the gap 2. The magnets 1 are made with pole pieces 5 equipped with non-ferromagnetic the 6E inserts and the coils of the magnetosensitive elements are connected to the recorder 7.

The device works as follows.

The distance between the magnetically sensitive elements 4 and the magnets 1 is pre-adjusted to

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transferring the magnitude of the magnetization of the core of the element 4 to the working area of the tesla-ampere characteristic. In practice, this distance is between 1 and 10 mm and depends on the area.

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core section and magnetization curve. So with the sizes of magnets 150x30x30 mm and induction В 1Тл, the cross section of the core of the element is 48 30 mm (30x1) and the length of the core 1 120 mm, the working distance is 6 mm. When working with a rope of d 42 mm, a section measurement in the range of 70-100% is provided with an accuracy of ± 1%. Due to the small distance between the middle part of magnet 1 and element 4, its core is in strong magnetic fields and therefore does not require shielding from weak external fields. If the cross section of the metal of the rope 3 placed between the inserts 6 corresponds to the nominal, then the coils of the elements 4 connected to the recorder 7 flow through the nominal current corresponding to 100% of the cross section.

Moving the rope 3 relative to the control device, the recorder 7 records the change in the current of the elements 4. The reduction in the metal cross section of the rope 3 leads to a decrease in the magnetic flux through it and to an increase in the magnetic flux through the element 4. Judging by the magnitude of the change (increase) in the current of the elements 4 rope section 3.

Calculations show that with a change in the magnetic flux through the cable 3 by 2%, the magnetic flux through the magnetically sensitive element 4 changes by 17%, which provides an increase in sensitivity several times in comparison with the known method of installing the magnetosensitive elements JTOB. In this case, the real sensitivity reaches 0.1%. This makes it possible to reduce the working induction and, therefore, the mass of the magnets 1 and the entire device.

Thus, the proposed device for controlling the cross section of steel ropes makes it possible to adjust the magnetic flux through the elements 4 (operating point) by moving them relative to the axis of the gap, eliminating the influence of the magnetic sensitive elements 4 on the geometry of the magnetizing flux of the rope 3, which is inevitable with the known methods installation, reducing the size and weight of the device by operating in the optimal magnetic flux, eliminating the influence of the geometry of the rope (stranding) on the operation of the elements 4.

Claims (2)

1. A device for controlling the cross section of steel cables, containing two P-shaped magnets facing each other with the same poles, forming A gap for placement of a controlled rope, and magnetically sensitive elements, characterized in that, in order to increase the accuracy and reduce the size of the device, the magnetically sensitive elements are oriented with their sensitivity axis parallel to the longitudinal axis of the gap and are installed symmetrically relative to this axis at the outer surface of the middle part of the U-shaped magnets movable in a direction perpendicular to the longitudinal axis of the gap. 2. A device according to claim 1, characterized in that the magnetically sensitive elements are made in the form of a coil with a ferromagnetic core.