JP6600331B2 - Magnetic powder concentration measuring method of magnetic powder liquid, magnetic powder concentration measuring device of magnetic powder liquid - Google Patents

Description

  The present invention relates to a magnetic powder concentration measuring method for measuring a magnetic powder concentration of a magnetic powder liquid used for magnetic particle inspection, and a magnetic powder concentration measuring apparatus for the magnetic powder liquid.

  As one of the nondestructive inspection techniques, a magnetic particle flaw detection method using a magnetic powder liquid is known. In such a magnetic particle flaw detection method, since the magnetic powder liquid is generally used repeatedly, the magnetic powder is gradually lost by adhering to the object to be inspected, whereby the magnetic powder concentration of the magnetic powder liquid gradually increases. It will drop to. Further, when shot powder or the like generated in the previous process is mixed, it may hinder the detection of scratches. Therefore, in order to detect the scratches on the test object with high accuracy, the magnetic powder concentration of the magnetic powder liquid is periodically measured, for example, supplemented with magnetic powder or replaced with a new magnetic powder liquid. Must be maintained within an appropriate range.

  As an example of a method for measuring the magnetic powder concentration of a magnetic powder liquid, a measuring method using a precipitation meter defined in JIS standards is well known. This is a measurement method in which the magnetic powder solution is placed in a precipitation meter and allowed to stand for 30 minutes, and then the scale of the precipitation amount of the magnetic powder is directly read. However, the measuring method using a precipitation meter needs to be left for 30 minutes, so that it takes a long time to measure, and depending on the type of magnetic powder, the magnetic powder cannot be precipitated in 30 minutes. Furthermore, since the measuring method using a precipitation meter is a method of visually reading the scale, there is a problem that high-precision measurement is difficult and variation tends to occur depending on the measurer.

  As a conventional technique for solving such a problem, for example, a container containing a magnetic powder solution is inserted into an air-core coil, a change in inductance generated at that time is detected as a voltage value, and the magnetic powder is detected from the voltage value. A method for measuring the magnetic powder concentration of a liquid is known (see, for example, Patent Document 1).

JP 2009-058286 A

  However, in the above prior art, there is a possibility that metals other than magnetic powder (iron powder) such as nonmagnetic metals mixed in the process of magnetic particle flaw detection may be measured as magnetic powder, so the magnetic powder concentration of the magnetic powder liquid is highly accurate. Measurement may not be possible.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a magnetic powder concentration measuring method and a magnetic powder concentration measuring apparatus for magnetic powder liquid that can measure the magnetic powder concentration of the magnetic powder liquid with high accuracy. is there.

<First Aspect of the Present Invention>
According to a first aspect of the present invention, a predetermined amount of magnetic powder to be measured is placed in a container formed of a non-magnetic material, and a magnetic field is generated from the outside of the container to the magnetic powder in the container. The magnetic powder in the liquid is accumulated, and the portion of the container where the magnetic powder is accumulated is inserted into the search coil or moved in the vicinity of the search coil. It is a magnetic powder concentration measurement method of a magnetic powder liquid which integrates a voltage, measures the magnetic flux amount, and calculates the magnetic powder concentration of the magnetic powder liquid in the container based on the measured magnetic flux amount.

  By generating a magnetic field in the magnetic powder liquid in the container from the outside of the container and accumulating the magnetic powder in the magnetic powder liquid, it is possible to eliminate nonmagnetic materials that can be contained in the magnetic powder liquid. And by measuring the magnetic flux amount of the accumulated magnetic powder with a search coil, metals other than magnetic powder (iron powder) such as nonmagnetic metals mixed in the process of magnetic particle flaw detection are also measured as magnetic powder. The fear can be reduced.

  Thereby, according to the 1st aspect of this invention, the effect that the magnetic-powder density | concentration of a magnetic-powder liquid can be measured with high precision is acquired.

<Second Aspect of the Present Invention>
According to a second aspect of the present invention, in the first aspect of the present invention described above, a plurality of magnetic powder samples having different magnetic powder concentrations and having different magnetic powder concentrations are used. Measure the amount of magnetic flux in the part where the magnetic powder is accumulated in advance, create in advance a calibration curve showing the relationship between the amount of magnetic flux and the magnetic powder concentration, and specify the magnetic powder concentration of the magnetic powder liquid to be measured from the calibration curve This is a magnetic powder concentration measuring method of the magnetic powder liquid.
According to the 2nd aspect of this invention, the magnetic powder density | concentration of the magnetic powder liquid used as a measuring object can be immediately identified from a calibration curve by producing beforehand the calibration curve which shows the relationship between magnetic flux amount and magnetic powder concentration.

<Third Aspect of the Present Invention>
A third aspect of the present invention is a container made of a non-magnetic material and containing a magnetic powder liquid to be measured, and a magnetic field generated in the magnetic powder liquid by generating a magnetic field from the outside of the container to the magnetic powder liquid in the container. A magnetic field generator for integrating the body, a search coil through which the container is inserted or moved in the vicinity, a magnetometer for measuring the amount of magnetic flux by integrating an electromotive voltage generated in the search coil, and the magnetic flux And an arithmetic processing unit configured to calculate a magnetic powder concentration of the magnetic powder liquid in the container based on an amount of magnetic flux measured by a meter.
According to the third aspect of the present invention, in the magnetic powder concentration measuring apparatus for magnetic powder liquid, the same effects as those of the first aspect of the present invention described above can be obtained.

<Fourth aspect of the present invention>
According to a fourth aspect of the present invention, in the third aspect of the present invention described above, the arithmetic processing unit uses the plurality of magnetic powder liquid samples having different magnetic powder concentrations with known magnetic powder concentrations. For each of the samples, the magnetic flux amount of the portion where the magnetic powder is accumulated is measured in advance, a calibration curve indicating the relationship between the magnetic flux amount and the magnetic powder concentration is prepared in advance, and the magnetic powder concentration of the magnetic powder liquid to be measured Is a magnetic powder concentration measuring device of a magnetic powder liquid, which is configured to identify from the calibration curve.
According to the fourth aspect of the present invention, in the magnetic powder concentration measuring apparatus of the magnetic powder liquid, the same effects as those of the second aspect of the present invention described above can be obtained.

  ADVANTAGE OF THE INVENTION According to this invention, the magnetic-powder-concentration measuring method of the magnetic-powder liquid which can measure the magnetic-powder density of a magnetic-powder liquid with high precision, and the magnetic-powder-concentration measuring apparatus of a magnetic-powder liquid can be provided.

The perspective view which illustrated the composition of the magnetic-powder concentration measuring device of the magnetic-powder liquid concerning the present invention. The front view which illustrated the principal part of the magnetic-powder concentration measuring apparatus of the magnetic-powder liquid which concerns on this invention. The front view which illustrated the principal part of the magnetic-powder concentration measuring apparatus of the magnetic-powder liquid which concerns on this invention. The front view which illustrated other Examples of the magnetic-powder concentration measuring apparatus of the magnetic-powder liquid which concerns on this invention. The front view which illustrated other Examples of the magnetic-powder concentration measuring apparatus of the magnetic-powder liquid which concerns on this invention. The graph which illustrated the calibration curve which shows the relationship between magnetic flux amount and magnetic powder density | concentration.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
In addition, this invention is not specifically limited to the Example demonstrated below, It cannot be overemphasized that a various deformation | transformation is possible within the range of the invention described in the claim.

The configuration of the magnetic powder concentration measuring device for magnetic powder according to the present invention will be described with reference to FIGS.
FIG. 1 is a perspective view illustrating the configuration of a magnetic powder concentration measuring apparatus for magnetic powder liquid according to the present invention. FIG.2 and FIG.3 is the front view which illustrated the principal part of the magnetic-powder concentration measuring apparatus of the magnetic-powder liquid which concerns on this invention. 4 and 5 are front views illustrating another embodiment of the magnetic powder concentration measuring apparatus of the magnetic powder liquid according to the present invention.

  The magnetic powder concentration measuring apparatus for magnetic powder according to the present invention includes a container 11, a permanent magnet 31, a search coil 32, a magnetometer 33, and an arithmetic processing unit 34.

  The container 11 is a container in which the magnetic powder liquid 20 to be measured is placed. More specifically, the container 11 is made of a nonmagnetic material such as glass or plastic.

  The permanent magnet 31 as a “magnetic field generating unit” generates a magnetic field from the outside of the container 11 to the magnetic powder liquid 20 in the container 11 and accumulates the magnetic powder 21 in the magnetic powder liquid 20. More specifically, the permanent magnet 31 has a cylindrical shape as illustrated, and generates a magnetic field in the magnetic powder liquid 20 from the bottom surface side of the container 11. As the permanent magnet 31 “magnetic field generator”, not only the permanent magnet 31 as in the embodiment but also an electromagnet may be used, for example.

  In the search coil 32, the container 11 is inserted, or the container 11 moves in the vicinity. The search coil 32 is arranged so that the relative positional relationship with the permanent magnet 31 does not change so as not to detect the magnetic flux of the permanent magnet 31. More specifically, the search coil 32 has an inner diameter larger than the diameter of the container 11, and for example, as shown in FIGS. 2 and 3, the center of the search coil 32 and the center of the permanent magnet 31 substantially coincide with each other. , Fixed at a predetermined position above the permanent magnet 31. Alternatively, the search coil 32 may be fixedly disposed around the permanent magnet 31, for example, as shown in FIGS.

  The magnetometer 33 is a known measuring device that measures the amount of magnetic flux by integrating the electromotive voltage generated in the search coil 32. The arithmetic processing unit 34 is an arithmetic processing device such as a personal computer, for example, and is configured to calculate the magnetic powder concentration of the magnetic powder liquid 20 in the container 11 based on the amount of magnetic flux measured by the magnetometer 33.

  The magnetic powder concentration measuring method of the magnetic powder liquid according to the present invention will be described with reference to FIGS.

  First, a predetermined amount of the magnetic powder liquid 20 to be measured is put into the container 11, and a magnetic field is generated from the outside of the container 11 to the magnetic powder liquid 20 in the container 11 to accumulate the magnetic powder 21 in the magnetic powder liquid 20. More specifically, the container 11 containing a predetermined amount of the magnetic powder liquid 20 to be measured is placed on the upper surface of the permanent magnet 31. Thereby, a magnetic field acts on the magnetic powder liquid 20 from the bottom surface side of the container 11, and the magnetic powder 21 contained in the magnetic powder liquid 20 in the container 11 is accumulated on the inner bottom surface of the container 11 (FIGS. 2 and 4).

  Subsequently, the portion of the container 11 where the magnetic powder 21 is accumulated is inserted into the search coil 32, and the electromotive force generated in the search coil 32 at that time is integrated to measure the amount of magnetic flux. More specifically, in the embodiment shown in FIGS. 2 and 3, the container 11 is moved upward as shown by the symbol A to search the portion of the container 11 where the magnetic powder 21 is accumulated. The magnetic flux amount is measured by the magnetometer 33 through the coil 32. Alternatively, the portion of the container 11 where the magnetic powder 21 is accumulated may be moved in the vicinity of the search coil 32, and the electromotive force generated in the search coil 32 at that time may be integrated to measure the amount of magnetic flux. More specifically, in another embodiment shown in FIGS. 4 and 5, the part in which the magnetic powder 21 of the container 11 is accumulated by moving the container 11 upward as shown by the symbol B. Is moved in the vicinity of the search coil 32, and the magnetic flux amount is measured by the magnetometer 33.

  Based on the measured magnetic flux amount, the magnetic powder concentration of the magnetic powder liquid 20 in the container 11 is calculated. Hereinafter, an example of a method for calculating the magnetic particle concentration based on the measured magnetic flux amount will be described with reference to FIG. FIG. 6 is a graph illustrating a calibration curve CC showing the relationship between the magnetic flux amount and the magnetic powder concentration.

  The calibration curve CC shown in FIG. 6 is created in advance using a plurality of samples of the magnetic powder liquid 20 having known magnetic powder concentrations and different magnetic powder concentrations. In the graph illustrated in FIG. 6, the vertical axis represents the amount of magnetic flux in the portion where the magnetic powder 21 is accumulated, and the horizontal axis represents the magnetic powder concentration (gram / liter). More specifically, the magnetic flux amount PA to PC of the portion where the magnetic powder 21 is accumulated is measured in advance for each of the three magnetic powder liquid 20 samples having known magnetic powder concentrations but different magnetic powder concentrations. A calibration curve CC indicating the relationship between the PC and the known magnetic powder concentration is prepared in advance. And the magnetic powder density | concentration of the magnetic powder liquid 20 used as a measuring object is specified from the calibration curve CC. The procedure for creating the calibration curve CC and specifying the magnetic powder concentration of the magnetic powder liquid 20 to be measured from the calibration curve CC may be executed by the arithmetic processing unit 34, for example. Thus, by preparing in advance the calibration curve CC indicating the relationship between the magnetic flux amount and the magnetic powder concentration, the magnetic powder concentration of the magnetic powder liquid 20 to be measured can be immediately identified from the calibration curve CC.

  As described above, according to the present invention, a magnetic field is generated from the outside of the container 11 to the magnetic powder liquid 20 in the container 11 to accumulate the magnetic powder 21 in the magnetic powder liquid 20, thereby being included in the magnetic powder liquid 20. The possible nonmagnetic material can be eliminated. By measuring the amount of magnetic flux of the accumulated magnetic powder 21 with the search coil 32, for example, a metal other than magnetic powder (iron powder) such as non-magnetic metal mixed in the process of magnetic particle inspection is also measured as magnetic powder. It is possible to reduce the risk of being lost. Thereby, the effect that the magnetic powder concentration of the magnetic powder liquid 20 can be measured with high accuracy is obtained.

11 Container 20 Magnetic Powder 21 Magnetic Powder 31 Permanent Magnet 32 Search Coil 33 Magnetometer 34 Arithmetic Processing Unit

Claims (4)

Put a certain amount of magnetic powder to be measured into a container made of non-magnetic material,
Generating a magnetic field in the magnetic powder liquid in the container from the outside of the container to accumulate the magnetic powder in the magnetic powder liquid,
The portion of the container where the magnetic powder is accumulated is inserted into the search coil or moved in the vicinity of the search coil, and the amount of magnetic flux is measured by integrating the electromotive voltage generated at the search coil at that time. ,
A magnetic powder concentration measurement method for a magnetic powder liquid, wherein the magnetic powder concentration of the magnetic powder liquid in the container is calculated based on the measured magnetic flux amount. The magnetic powder concentration measuring method according to claim 1, wherein the magnetic powder is collected for each of the plurality of magnetic powder liquid samples using a plurality of magnetic powder liquid samples having different magnetic powder concentrations with known magnetic powder concentrations. The amount of magnetic flux of the part being measured is measured in advance, a calibration curve indicating the relationship between the amount of magnetic flux and the concentration of magnetic powder is created in advance,
A magnetic powder concentration measuring method of a magnetic powder liquid, wherein the magnetic powder concentration of the magnetic powder liquid to be measured is specified from the calibration curve. A container made of a non-magnetic material and containing a magnetic powder to be measured;
A magnetic field generating unit that accumulates magnetic powder in the magnetic powder liquid by generating a magnetic field from the outside of the container to the magnetic powder liquid in the container;
A search coil through which the container is inserted or moved in the vicinity;
A magnetometer that integrates the electromotive voltage generated in the search coil to measure the amount of magnetic flux;
A magnetic powder concentration measuring apparatus for a magnetic powder liquid, comprising: an arithmetic processing unit configured to calculate a magnetic powder concentration of the magnetic powder liquid in the container based on an amount of magnetic flux measured by the magnetometer. 4. The magnetic powder concentration measuring apparatus according to claim 3, wherein the arithmetic processing unit uses a plurality of magnetic powder liquid samples having known magnetic powder concentrations and different magnetic powder concentrations, for each of the plurality of magnetic powder liquid samples. Preliminarily measure the amount of magnetic flux in the portion where the magnetic powder is integrated, and create a calibration curve in advance showing the relationship between the amount of magnetic flux and the concentration of magnetic powder,
A magnetic powder concentration measuring apparatus for magnetic powder liquid, configured to identify the magnetic powder concentration of the magnetic powder liquid to be measured from the calibration curve.

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