JP4958123B2 - Powder inspection method - Google Patents

Description

  The present invention relates to a powder inspection method in which a glass plate is brought into contact with powder and the color of the surface of the powder is measured with a colorimeter through the glass plate in order to control the quality of the powder.

Conventionally, in order to control the quality of powder, an inspection method for measuring the color and inspecting whether or not it has a prescribed color has been performed.
For example, the standard value of L ^* , a ^* , b ^* in the LAB color system is determined, the color of the powder to be managed is measured with a colorimeter, and each value of L ^* , a ^* , b ^* is determined. A method of comparing with the reference value and making a pass / fail judgment based on the difference is adopted for powder quality control.

Such powder quality control has been studied to be applied to material management of cement composition used for the production of concrete products. For example, Patent Document 1 listed below discloses fly ash selection and fly ash selection. It is described that the color of ash is measured to determine the amount of ash used.
Patent Document 2 below describes that the color of a fine aggregate is measured and the moisture content is determined based on the obtained brightness value.

By the way, the color measurement by the colorimeter is usually carried out by defining a circular region having a diameter of several centimeters on the surface of the object to be measured by a light shielding cylinder. Concavities and convexities are likely to be formed in the region, and when the same powder is measured multiple times, the formation state of the concavities and convexities is different each time, so that stable measurement is difficult. It has been known.
And in the following Patent Document 3, a fixed amount of powder to be measured is put into a cylindrical container, and the powder is uniformly filled by applying vibration to the container using a dedicated vibration device. Although described, in such a method, not only a dedicated vibration device is required but also a mixed powder containing two or more kinds of components having different specific gravity is used to measure the color of the mixed powder. This may result in the measurement of the color of the light specific gravity component without being made.
On the other hand, Patent Document 2 described above describes that stable data can be easily obtained by bringing a glass plate into contact with the powder surface and performing colorimetry through the glass plate (paragraph). [0017]).

JP 2002-14039 A JP-A-10-59755 JP-A-7-270287

Conventionally, when measuring the color of a powder, it has been considered to perform stable measurement as described above, but a method for performing highly reproducible measurement has not been established so far, and it has been performed multiple times. Therefore, it is difficult to reduce the labor required for the powder inspection, such as the need for measurement.
The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a powder inspection method capable of reducing labor required for inspection as compared with conventional inspection methods.

As a result of intensive studies to solve the above-mentioned problems, the inventors of the present invention disclosed, for example, the invention described in Patent Document 2 without a special treatment for adjusting the condition of the powder, for example, in a piled state. Since the glass plate is pressed against the powder and the color is measured through the glass plate, it is difficult to equalize the contact state between the glass plate and the powder in the measurement region, and the color measurement value It was found that there was a variation in.
And the simple method of equalizing the contact state of a glass plate and powder was examined, and it came to complete this invention.

That is, the present invention according to the inspection method of the powder, the powder inside opening is formed in the housing can be a powder container in the upper part, so that the state rises upward beyond the opening An accommodating step of accommodating the powder in
A scraping step of cutting the powder along the edge of the opening to produce a flat surface formed by the powder inside the opening;
A cylindrical main body, and one end of the cylindrical main body is formed to be attachable to a colorimeter, and an opening for defining a measurement region by the colorimeter is formed at the other end of the cylindrical main body. Using a target mask that is formed and whose opening is covered with a glass plate, the other end is brought into contact with the flat surface, and then the powder is placed below the flat surface at the other end. Pressing down to a predetermined depth to the side, passing the glass plate against the pressed powder surface, and measuring the color of the powder surface with a colorimeter, and
In the accommodation step and the scraping step, the powder forming the flat surface is in a state of being accommodated in a natural state,
The diameter of the opening of the powder container is larger than the other end and equal to or less than the one end,
In the measurement step, the powder is pushed down below the flat surface by pushing down the other end to a depth at which the outer periphery of the one end contacts the opening edge of the powder container . .

In the conventional powder inspection method, for example, as described in FIG. 2 of the above-mentioned Patent Document 2, a glass plate is pressed against a piled powder to measure the color. In the plane where the powder and the powder come into contact, there is a possibility that a portion where the powder is strongly compressed by the glass plate and a portion where the powder is hardly compressed are formed.
In some cases, air may be interposed between the glass plate and a region that is not in contact with the powder may be formed.

On the other hand, according to the present invention, a flat surface made of powder is formed by the abrasion process, and after bringing the glass plate into contact with the flat surface, the powder is further moved downward from the flat surface with the glass plate. Press down to measure the color on the powder surface.
In addition, the powder forming the flat surface before being pushed down by the glass plate is in a natural state.
The “natural state” means, for example, a state in which no substantial pressure operation or the like is performed on the powder, and without performing an operation to increase the bulk density such as applying pressure or vibration, It means a state obtained by allowing powder to be stored in a powder container by natural fall.
In addition, if it is from the state accommodated by natural fall to the extent that the bulk density becomes 1.1 times, it can be regarded as a substantially natural state, and if it is 1.05 times or less, it is more clearly natural. It can be regarded as a state.
For example, in the case of cement powder, when the true specific gravity is 2.8 to 3.3 and the Blaine specific surface area is 3000 to 4500 cm ² / g, the powder is “natural” if the bulk density is 1.05 g / cm ³ or less. It can be regarded as “the state”.

In this way, the surface in contact with the glass plate is a flat surface, and color measurement is performed on the powder that is in a natural state, so that variation occurs in the surface where the glass plate and the powder are in contact with each other. The risk of occurrence can be suppressed as compared with the conventional method.
That is, the contact state between the glass plate and the powder in the color measurement region can be made uniform.
In addition, by setting the depth at which the glass plate is pushed down to a predetermined depth, variations when performing multiple measurements can be suppressed.
That is, according to the present invention, it is possible to provide a powder inspection method capable of reducing labor required for inspection as compared with a conventional inspection method.

The schematic process drawing which shows the inspection method of the powder of one embodiment. The schematic process drawing which shows the inspection method of the powder of other embodiments. The schematic process drawing which shows the inspection method of the powder of other embodiments. The schematic process drawing which shows the inspection method of the powder of other embodiments.

Hereinafter, an embodiment of the present invention will be described by giving an example of measuring the color of cement powder as a powder inspection method.
First, devices used will be described with reference to the drawings.
In addition, in FIG. 1, the partial notch sectional drawing of the powder container 1 used for the inspection method of the powder which concerns on this embodiment, and the front view of the colorimetry apparatus 2 are shown, and the color of the cement powder C is measured by these. The procedure to do is shown.

The color measuring device 2 is composed of a colorimeter 20 and a target mask 21 with a glass plate, and measures the color of the object to be measured in a state where the colorimeter 20 and the target mask 21 with a glass plate are connected. Shaped to get.
The colorimeter 20 usually has a light source for irradiating measurement light to the object to be measured, and is a circular measurement window for irradiating light from the light source and capturing reflected light from the object to be measured. 20a.
The target mask 21 with a glass plate is composed of a cylindrical main body 22 serving as a light-shielding cylinder and a glass plate 23 that is in contact with the object to be measured.
More specifically, the cylindrical main body 22 is formed in a cylindrical shape whose diameter decreases from one end 22a to the other end 22b, and has a truncated cone shape as a whole.
And the said target mask 21 with a glass plate can be mounted | worn with the colorimeter 20 by connecting the said one end part 22a used as a large diameter side to the said measurement window 20a, and the said other end part 22b used as a small diameter side. Is formed with a circular opening smaller than the measurement window 20a.
The glass plate 23 is formed in a disk shape that is slightly larger than the opening of the other end 22b, and is attached to the cylindrical main body 22 so as to cover the opening from the outside.
Therefore, the colorimetric device 2 irradiates the measuring light from the colorimeter 20 with the target mask 21 with glass plate attached to the colorimeter 20 and from the opening provided at the tip thereof, The object to be measured is irradiated with light through the glass plate 23 covering the opening, and the light reflected from the surface of the object to be measured is taken into the cylindrical main body 22 through the glass plate 23 so that the color can be measured. It is configured.

About the said colorimeter 20, what is marketed can be used as a "color meter", a "color difference meter", etc., for example, what has C light source, D65 light source, etc. as said light source, The said glass plate attached Examples of the target mask 21 include those that allow the colorimeter to perform a measurement with a viewing angle of 2 degrees.
As this colorimeter 20, what can measure the colorimetric data based on JISZ8729 (2004) can be normally used.
More specifically, a CIE (1976) L ^* a ^* b ^* color space called CIELAB, CIELV, etc., a value (L ^* ) indicating the lightness in the CIE (1976) L ^* u ^* v ^* color space, Can measure the hue and saturation values (a ^* , b ^* , u ^* , v ^* ), XYZ color system, Hunter, Munsell, etc. In particular, the L ^* value of CIELAB and CIEUV is particularly useful for quality control of cement powder and the like, and those capable of measuring this L ^* value are suitable.

The powder container 1 in the present embodiment is a bottomed container having an opening 1x in the upper part, and has a circular shape inside by a substantially circular bottom surface 11 and a peripheral side wall 12 erected from the peripheral edge of the bottom surface 11. A columnar storage space is formed.
The peripheral side wall 12 has the same height from the bottom surface to the upper edge 12a in the entire circumference, and the upper edge 12a is positioned on the same plane.
That is, the upper edge 12a of the peripheral side wall 12 has the same circular shape as the bottom surface 11 on the same plane, and defines the opening 1x in the circular shape.
The powder container 1 has a diameter such that the opening 1x is larger in diameter than the other end 22b of the cylindrical main body 22 of the target mask 21 with glass plate and less than or equal to one end 22a. When the target mask 21 with glass plate is inserted into the accommodation space from the opening 1x, the tapered outer peripheral surface of the cylindrical main body 22 is brought into contact with the opening edge of the glass plate 23 to a certain depth. It is formed so that it can be stopped.

  The measurement of the color of the cement powder using the powder container 1 and the color measuring device 2 is performed so that the powder container 1 is in a state where it rises upward beyond the opening 1x. An accommodating step for accommodating the powder C, and scraping along the edge of the opening 1x (the upper edge 12a of the peripheral side wall 12) to form a flat surface FS formed by the cement powder C inside the opening 1x After performing the scraping process to produce, it implements by making the glass plate 23 of the said target mask 21 with a glass plate with which the colorimeter 20 was mounted | worn contact | abut to the said flat surface FS.

  More specifically, after the glass plate 23 is brought into contact with the flat surface FS, the calorimeter 20 is further moved from the upper side to the lower side so as to push down the cement powder C with the glass plate 23, and the opening 1x. When the glass plate 23 is stopped at a predetermined depth (for example, 5 mm to 30 mm depth) by bringing the outer peripheral surface of the target mask 21 into contact, color measurement is performed by the colorimeter 20.

Accordingly, it is possible to suppress the presence of air or the like on the contact surface between the glass plate 23 and the cement powder C pushed downward from the flat surface FS by the glass plate 23, thereby suppressing contact unevenness. obtain.
In the powder inspection method according to the present embodiment, the cement powder C forming the flat surface FS is accommodated in the powder container 1 in a natural state before the glass plate 23 is entered. is important.
Thereby, the contact pressure between the glass plate 23 and the cement powder C can be adjusted by the depth of penetration of the glass plate 23.
That is, in order to obtain a more stable measurement result, it is important that the cement powder C forming the flat surface FS is accommodated in the powder container 1 in a natural state before the glass plate 23 is entered. is there.

  More specifically, when the cement powder C is stored in the powder container 1 in the storing step, the cement powder C is pressurized from above so as to push in, or the powder container 1 is vibrated to fill the cement powder C. When the operation of increasing the density is performed, when measuring another cement powder, it is practically impossible to store the cement powder in the powder container 1 under the same pressure state as this time. Later, when the glass plate is brought into contact, the state of contact between the cement powder C and another cement powder will be different.

  The same applies to the scraping step, and forming the flat surface FS in a certain condition is an important factor in measuring with little variation.

In order to store the cement powder C in the powder container 1 in such a state, for example, the cement powder C is naturally dropped from the upper part of the opening 1x, or a wire mesh for breaking up the aggregates as necessary. And a method of removing the excess cement powder C without pressurizing the cement powder C in the scraping step.
Further, this scraping step is performed, for example, by bringing a flat member B such as a blade or a spatula into contact with the powder container 1 from above in a state where the surface thereof is vertically oriented, It can be carried out by moving along the upper edge 12a of the peripheral side wall 12 forming the opening 1x, and is flattened by removing the cement powder raised above the opening 1x by the flat plate member B. The surface FS can be formed.

In the storing step, it is not necessary to make the interior of the powder container 1 all natural. For example, the cement powder C may be pressurized and filled near the bottom surface 11 of the powder container 1. The effect on the stability of the measurement results is low.
Therefore, the cement powder C at least from the flat surface FS to the depth at which the glass plate 23 is allowed to enter may be accommodated in a natural state, and pressure-filled in a place that does not affect such measurement. The case is also within the range intended as the powder inspection method of the present invention.

In order to obtain a stable measurement result, it is preferable to secure the depth of the cement powder C accommodated in this natural state to some extent.
For example, when a portion below the depth of penetration of the glass plate 23 is pressure-filled, the difference due to the pressure applied during the pressure-filling may affect the color measurement result.
For this reason, it is preferable that the cement powder C is accommodated in a natural state at a depth of 1.5 times or more, preferably 2 times or more the depth of penetration of the glass plate 23.

In this manner, the surface color of the cement powder C measured by the colorimeter 20 through the glass plate 23 is observed as a stable measurement result, with variations in data for each measurement being suppressed.
Therefore, according to the present invention, it is possible to omit an extra measurement in order to confirm the reliability of the measurement result and an averaging by performing a large number of measurements in order to reduce an error. The time required can be reduced.
In addition, it is possible to provide highly reliable data when measuring cement powders of different production lots and using each measurement result as a material for relative comparison.
In particular, since the L ^* value of CIELAB or CIEUV can be easily changed depending on the condition of the cement powder, the powder inspection method as in the present invention can be used, and the cement powder itself, fine aggregate, etc. It is useful as a management item when quality control of a cement composition mixed with the above powder is performed.

  In addition, in the above, the case where a bottomed container is used as a powder container is illustrated, but not limited to such a bottomed container, for example, if an opening is formed in the upper part, A cylindrical powder container 1 ′ as shown in FIG. 2 can also be used.

FIG. 2 shows a side view of a process using the cylindrical powder container 1 ′. For example, as shown in FIG. 2, cement powder C is deposited in a natural state to form the powder. A ridge higher than the body container 1 ′ is formed, and the powder container 1 ′ is inserted into the ridge of the cement powder C from above, and above the upper edge 12 a ′ of the peripheral side wall 12 ′. If the powder container 1 ′ is moved downward until the cement powder C reaches, and then a scraping process is performed in the same manner as the method illustrated in FIG. 1, the cement powder C in the natural state causes the inside of the opening 1x ′. Can form a flat surface.
And with respect to the point that a stable measurement result can be obtained by carrying out the measurement of the color by making the target mask with glass plate enter a predetermined depth with respect to this flat surface, The same.

Incidentally, as described above SL, 1 and 2, although the size of the accommodating space in the vertical direction illustrate the powder container 1, 1 'with no change, for example, a bottom of FIG. 1 Instead of the powder container 1, it is also possible to use a die cup-shaped powder container 1 ″ formed so that the accommodation space becomes narrower toward the bottom as shown in FIG. 4.
Further, in the examples shown in FIGS. 1 and 2, the colorimeter is mounted with a target mask with a glass plate, and the colorimeter and the glass plate are integrated, but as shown in FIG. The plate 23x is brought into contact with the flat surface FS after the abrasion process, the glass plate 23x is operated to push down the powder downward, and then the colorimeter 20 equipped with the light-shielding cylinder 22x not fitted with the glass plate. The method of inspecting the powder color by measuring the color of the powder by bringing the tip of the light shielding cylinder 22x into contact with the upper surface of the glass plate 23x is also within the range intended as the powder inspection method of the present invention.

  Furthermore, various improvements other than these can be added, and conventionally, technical matters useful when measuring the color of powder with a colorimeter are employed within a range where the effects of the present invention are not significantly impaired. Is possible.

  EXAMPLES Next, although an Example is given and this invention is demonstrated in more detail, this invention is not limited to these.

(Color measuring device)
As a colorimeter, a color difference meter “CR-400” manufactured by Konica Minolta was used, and a target mask “CR-A33f” with a glass plate was attached thereto to constitute a colorimeter.
The “CR-A33f” is formed in a shape that is reduced in diameter toward the front end portion to which the glass plate is attached, similar to the target mask with glass plate shown in FIG.

(Measurement target)
Prepare two types of powders (powder A and powder B) with different brightness, prepare mixed powders with the following 5 types of mixing ratio (mass ratio), and measure color (brightness) with the above colorimetric device It was targeted.
Mixed powder 1: (A: B) = 79: 21
Mixed powder 2: (A: B) = 74: 26
Mixed powder 3: (A: B) = 69: 31
Mixed powder 4 : (A: B) = 59: 41

(Powder container)
The powder container for containing the mixed powder is larger in diameter than the tip of the above-mentioned target mask “CR-A33f” with glass plate, and smaller than the diameter on the side attached to the color difference meter “CR-400”. A 100 ml graduated polycup having an opening (substantial volume 132 ml) was prepared.

(Example)
As an example of the present invention, the color of the mixed powder was measured as follows.
First, the mixed powder is accommodated in the polycup, and after the mixed powder is accommodated so as to rise above the upper opening, a spatula formed of a thin metal plate is placed on its side edge. The mixed powder was scraped by sliding left and right while being in contact with the opening edge of the polycup to form a flat surface of the mixed powder inside the opening of the polycup.
In this example, the mixed powder was accommodated in a natural state in a polycup without applying vibration when the mixed powder was accommodated or pressing the powder downward from above.
In addition, even when scraping with a spatula, the work was carried out so that the flat surface to be formed would not be pressed by the spatula.
Next, the glass plate of the target mask with a glass plate is brought into contact with the flat surface, and further, the target mask with the glass plate attached to the colorimeter is pressed down on the powder forming the flat surface, When the target mask with a glass plate was in close contact with the upper end of the polycup, the brightness of the mixed powder (CIELAB L ^* value) was measured.
In this example, it was confirmed that the powder had a bulk density of 0.97 to 0.99 g / cm ³ and was accommodated in the polycup, and was in a natural state.

(Comparative example)
During accommodation the mixed powder for the plastic cup, except for increasing the packing density of the mixed powder for the plastic cup was added vibration was measured above embodiments as well as the mixed powder lightness (CIELAB L ^* value) .
In this comparative example, it was confirmed that the powder had a bulk density of 1.11 to 1.15 g / cm ³ and was accommodated in the polycup.

The mixed powders 1 to 4 were each subjected to five measurements for each of the examples and comparative examples, and the standard deviation of the obtained five L ^* value data was determined.
The results are shown in Table 1 below.

As described above, according to the present invention, it can be seen that measurement with little variation is possible.
It can also be seen from the above results that it is not sufficient to simply perform the measurement with the surface flattened, and it is important to adjust the powder to a state in which it is housed in a natural state.

DESCRIPTION OF SYMBOLS 1 Powder container 1 'Powder container 1 "Powder container 1x Opening 2 Color measuring device 11 Bottom face 12 Peripheral side wall 12a Upper edge 20 Colorimeter 20a Measuring window 21 Target mask 22 with glass plate Cylindrical main body 22a One end 22b Other end 22x Shading cylinder 23 Glass plate 23x Glass plate B Flat member C Cement powder FS Flat surface

Claims (2)

It said powder therein are openings formed in the housing can be a powder container in the upper part, an accommodating step of accommodating the powder so that the state rises upward beyond the opening,
A scraping step of cutting the powder along the edge of the opening to produce a flat surface formed by the powder inside the opening;
A cylindrical main body, and one end of the cylindrical main body is formed to be attachable to a colorimeter, and an opening for defining a measurement region by the colorimeter is formed at the other end of the cylindrical main body. Using a target mask that is formed and whose opening is covered with a glass plate, the other end is brought into contact with the flat surface, and then the powder is placed below the flat surface at the other end. Pressing down to a predetermined depth to the side, passing the glass plate against the pressed powder surface, and measuring the color of the powder surface with a colorimeter, and
In the accommodation step and the scraping step, the powder forming the flat surface is in a state of being accommodated in a natural state,
The diameter of the opening of the powder container is larger than the other end and equal to or less than the one end,
In the measurement step, the powder is pushed down below the flat surface by pushing down the other end to a depth where the outer periphery of the one end contacts the opening edge of the powder container. Powder inspection method. The method for inspecting powder according to claim 1, wherein the L ^* value of CIELAB or CIEUV based on JIS Z8729 is measured by the colorimeter.

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