JPS5950935B2 - Magnetic particle liquid dispersion device for magnetic particle flaw detection - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetic particle liquid dispersing device for magnetic particle flaw detection that scatters magnetic particle liquid in which magnetic particles are suspended onto the surface of an object to be inspected.

Magnetic particle testing is widely used to inspect linear defects occurring in ferromagnetic materials, intermediate products, finished products, and the like.

An example of a magnetic particle flaw detection apparatus to which the present invention is applied will be briefly described below. FIG. 1 is a perspective view of a magnetic particle flaw detection device equipped with a magnetic powder liquid dispersion device 1. As shown in FIG. The magnetizing device 2 includes an electromagnet consisting of an iron core 3 and a coil 4, and a power supply device (not shown) that supplies an alternating current of several hundred amperes to the coil 4. In front of and adjacent to the magnetizing device 2, a magnetic powder liquid dispersing device 1 is provided. To explain the method of detecting flaws in a long rectangular steel piece S using the magnetic particle flaw detection device configured as described above, while the rectangular steel piece S is moving forward in the direction of arrow A, magnetic particles are sprayed onto the upper surface of the rectangular steel piece S by the magnetic particle spraying device 1. Spray the liquid.

The square steel piece S sprinkled with the magnetic powder liquid further advances to the magnetization device 2.
and is magnetized here. If there is a linear defect F along the longitudinal direction of the square steel piece on or near the upper surface of the square steel piece S, lines of magnetic force cross the defect F, and a magnetic pole is generated at the defect portion. Then, the magnetic particles in the magnetic powder liquid dispersed in advance as described above are attracted to the magnetic poles, and a magnetic particle pattern indicating the defect F is formed. Fig. 2 shows an example of a conventional magnetic powder liquid dispersion device, in which a box-shaped main body 5 is attached to the bottom, and a plurality of dispersion nozzles 6 are installed in the width direction of the object to be inspected (perpendicular to the plane of the paper in Fig. 2). A gutter 7 is arranged in the main body 5 and extends in the width direction.

The magnetic powder liquid is supplied to the gutter 7 from the supply pipe 8, overflows from the gutter 7, and is sprayed onto the surface of the object S to be inspected through the spray nozzle 6. Incidentally, in order to detect defects with high accuracy, it is necessary to spray the magnetic powder liquid in an appropriate amount and uniformly, but in the conventional device as described above, the magnetic powder liquid is not uniformly dispersed. This is because the amount of spraying is relatively small (for example, about 41/min), and it is difficult to make such a small flow of magnetic powder liquid uniformly overflow from the gutter 7 along the width direction. That is, as the magnetic powder liquid moves away from the position where it flows into the gutter 7, the amount overflowing from the gutter 7 increases. There are various types of magnetic powder spraying devices with structures other than those described above, but all of them have the problem of not being able to uniformly spray the magnetic powder solution in an appropriate amount.

Therefore, the present invention solves the above-mentioned problems in magnetic particle dispersing devices, and provides a magnetic particle dispersing device for magnetic particle flaw detection that is simple in structure and capable of uniformly dispersing an appropriate amount of magnetic particle liquid. This is what I am trying to do.

Hereinafter, the present invention will be described in detail based on preferred embodiments with reference to the drawings.

3 and 4 show an example of the device of the present invention, and the magnetic powder spraying device is mainly composed of a main body 11, a magnetic powder supply pipe 18, a gutter 19, and a spraying nozzle 23.

The main body 11 has a channel 12 that spreads out in a fan shape toward the front and is inclined.
and is surrounded by a rear wall 15.

A shallow bowl-shaped recess 16 is located in the center of the flow path 12 near the rear end.
The edge 17 of the recess 16 is shaped like a semicircle projecting forward from the rear wall 15. In the main body 11 configured as described above, for example, the width of the flow path 12 is about 45° to 90°, and the inclination is about 1 to 10°,
Appropriately, the diameter of the recess 16 is about 40 to 60% of the magnetic powder liquid scattering width, and the depth is about 10 to 20% of the diameter of the recess 16.
The magnetic powder liquid supply pipe 18 opens directly above the recess 16, and supplies magnetic powder liquid sent at a constant flow rate to the recess 16 by a pump (not shown).

The gutter 19 is connected to the front edge 13 of the main body 11 so as to cross the channel 12, and both ends are closed with side plates 20. The lower part 21 of the gutter 19 narrows downward, and the bottom part 22 has a narrow flat bottom. Spraying nozzle 23
A plurality of rods are arranged on the bottom 22 of the gutter 19 along the longitudinal direction so as to face downward.

For example, the pitch between the spray nozzles 23 is 20 to 30 mm, and the nozzle inner diameter is about 6 to 10 mm. Next, the operation of the magnetic powder liquid dispersing device configured as above will be explained.

When the magnetic powder liquid is supplied from the magnetic powder liquid supply pipe 18 to the recess 16 of the main body 11 at an appropriate flow rate, the magnetic powder liquid collides with the magnetic powder liquid in the recess 6 to reduce the flow energy, and spreads toward the periphery to form the edge 17. It quietly overflows onto Gyeong Road 12.

The overflowing magnetic powder liquid spreads in the flow path 12, so the tip edge]
3, the flow rate decreases, and the liquid flows into the gutter 19 at a uniform depth and flow rate, and then flows down from the spray nozzle 23 onto the surface of the object S to be inspected. That is, a part of the magnetic powder liquid supplied to the recess 16 directly overflows from around the center of the semicircularly projecting edge 17 and flows down to the center of the channel 12, but in this case, the flow width There is a tendency for the liquid level at the center to be slightly high and to flow gradually lower with skirts to both sides.On the other hand, the remaining magnetic powder liquid collides with the rear wall 15 and overflows from near both ends of the semicircular bottom. Both side walls] 4 and 14 flow down, but the liquid level on the wall side is slightly higher in each of these flows,
There is a tendency for the flow rate to gradually decrease toward the center line of the flow path 12 in the flow direction. Due to the expansion and inclination of the flow path 12 at an appropriate level for the magnetic powder liquid described above, these flows sequentially merge below the flow path 12 and are adjusted to a mutually balanced liquid level. This creates a nearly uniform flow rate over the entire surface. Furthermore, the lower front end line 13 of this flow path 12
Since the length is similar to the length in the longitudinal direction of the gutter 19, the inflowing magnetic powder liquid is evenly supplied to the spray nozzle 23 without being biased in the gutter 19, and is sprayed on the object S to be inspected in an appropriate amount and uniformly. It is possible to perform magnetic particle flaw detection with high accuracy.

[Brief explanation of drawings]

Fig. 1 is a perspective view showing an example of a magnetic particle flaw detection device equipped with a conventional magnetic powder liquid dispersion device, Fig. 2 is a schematic sectional view showing an example of a conventional magnetic particle liquid dispersion device, and Fig. 3 is a magnetic particle liquid dispersion device of the present invention. FIG. 4 is a perspective view showing an example of a spraying device, and FIG. 4 is a schematic sectional view of the device shown in FIG. 3. DESCRIPTION OF SYMBOLS 1...magnetic powder liquid dispersion device, 2...magnetization device, 3...iron core, 4...coil, 5...
...Main body, 6...Spraying nozzle, 7...
... Gutter, 8 ... Supply pipe, 11 ... Main body, 12 ... Channel, 13 ... Front edge,
14...Side wall, 15...Rear wall, 16.
...Concavity, 17...Edge, 18...
・Supply pipe, 19...Gutter, 20...Side plate, 21...Lower, 22...Bottom, 23
...Scatter nozzle, S...Square steel piece, F.
·····defect.

Claims (1)

[Claims] 1. A main body having a flow path that widens toward the front and is inclined, and a recessed portion near the rear end of the flow path, a magnetic powder liquid supply pipe that opens directly above the recessed portion, and a flow path provided at the front end of the main body. A magnetic particle liquid dispersion device for magnetic particle flaw detection, comprising a gutter connected in a transverse manner, and a plurality of spraying nozzles extending downward and provided at the bottom of the gutter along the longitudinal direction thereof.