JP2948692B2 - Apparatus and method for measuring crushability of granular material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for measuring the pulverizability of a granular material capable of automatically and extremely quickly and accurately measuring the pulverizability of the granular material, and a method for measuring the pulverizability using the apparatus. is there.

[0002]

2. Description of the Related Art For example, coal used as a fuel in a thermal power plant or the like is often pulverized to a certain particle size, and it is necessary to accurately measure and evaluate the pulverizability of coal. For this reason, JIS M 8801 uses a hard glove crushing index (HG
It specifies a value called I). However, in order to measure this HGI by the method specified in the above JIS, one time
It requires 30 to 40 minutes, and cannot be applied to continuous measurement because it takes a lot of time for measurement. In addition, the operation is complicated and automation is difficult.

[0003]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned conventional problems and corrects the crushability of granular materials such as coal in a shorter time than the HGI measurement method specified in JIS. Completed to provide a grindability measuring device and a grindability measuring method for granular materials that can be measured automatically and can obtain measured values that are in good agreement with HGI measured by the method specified in JIS It was done.

[0004]

The above object is achieved by providing a fixed roll and a movable roll opposite to each other below a chute for supplying a granular material, and a stress measuring device for detecting a force applied to the movable roll. In addition, the present invention can be solved by an apparatus for measuring the crushability of a granular material, which comprises an integral arithmetic processing unit for obtaining crushability from the integrated value of the output.
Further, the above-mentioned problem is to perform a stress measurement of the granular material pulverized between a fixed roll and a movable roll rotating at a constant speed while supplying the granular material to the chute of the pulverizability measuring device,
The problem can be solved by a method for measuring the pulverizability of a granular material, wherein the pulverizability is obtained from the integrated value of the output of the stress measuring device.

[0005] In addition, as the granular material whose pulverizability is measured by the apparatus and method of the present invention, inorganic particles represented by minerals such as coal, feldspar and pottery stone and ceramics such as synthetic mullite and alumina can be used. In addition, organic particles such as synthetic resins and foods can also be mentioned. Hereinafter, the present invention will be described in more detail with reference to an example of the illustrated apparatus for measuring the grindability of coal particles.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIG. 1, reference numeral 1 denotes a frame, 2 denotes a frame of a feeder provided on the side of the frame, 3 denotes a feeder of a granular material as an object to be measured provided on the upper portion of the frame 2, and 4 denotes a granular material. A chute that can continuously supply the body at a constant speed.

The granular material preferably has a particle size of about 0.1 to 30 mm and is continuously supplied from the end of the feeder 3 to the upper end of the chute 4 at a constant speed. Supplied to The chute 4 is made of metal such as stainless steel and wear-resistant steel, ceramics such as silicon carbide and alumina, so as not to be worn or deformed by the collision of the granular material supplied from the feeder 3.
Further, a metal surface coated with an organic material or an inorganic material, an elastic material such as rubber, or the like can be used. The angle and position of the chute 4 are set so that the granular material rolls down from the lower end between the rolls with little resistance.

A fixed roll 6 having a shaft 5 fixed to the frame 1 and a movable roll 7 are provided on the frame 1 below the chute 4 so as to face each other in the horizontal direction. In the embodiment, the fixed roll 6 is driven by a motor (not shown) in the direction of the arrow, while the movable roll 7 is fixed to the tip of an L-shaped arm 8 by a shaft 9. In the embodiment, the driven roll has no driving source. Although a roll is used, the movable roll 7 may be actively driven to make the fixed roll 6 a driven roll, or both rolls may be driven.

The diameter of the fixed roll 6 is 400 mm in the embodiment, but can be appropriately selected depending on the size of the granular material as the object to be measured. The fixed roll 6 ensures that the granular material supplied from the chute 4 bites into the gap with the movable roll 7.
The diameter of the fixed roll 6 and the movable roll 7 is preferably about 5 to 5000 times the diameter of the granular material. The gap between the fixed roll 6 and the movable roll 7 is 1 / 1.4 to 1/10 times, particularly preferably 1 / 2.7 to 1 / 4.5 times, the diameter of the granular material. 20 μm or less. The surface of these rolls may be smooth, may be in a state of having irregularities by sandblasting or the like, or may be in a state of having grooves. As the material of the roll, a wear-resistant metal such as S45C, a metal surface having a wear-resistant coating such as vanadium, a ceramic such as silicon carbide, silicon nitride, and alumina can be used. Furthermore, the rotation speed of the roll is 0.3 to 60
A rpm is preferred, and the granules may be rotated only when supplied between the rolls, or may be constantly rotated. However, it is necessary that the rotational speed does not fluctuate during the measurement.

The arm 8 to which the movable roll 7 is attached is made of a material having sufficient strength so as not to bend. The arm 8 is pivotally mounted on the frame 1 by a horizontal shaft 10 and supplied from the chute 4. The reaction force when the granular material passes between the fixed roll 6 and the movable roll 7 causes the shaft 10 to move.
Slightly displaced about. To detect this displacement, the other end 11 of the arm 8 faces a U-shaped pressure receiving jig 12. A stress measuring device 13 such as a load cell is provided between the end 11 of the arm 8 and the pressure receiving jig 12, and detects a stress applied to the arm 8 as an electric signal. The stress measuring device 13 is not limited to a load cell. 14 is a column for preventing the arm 8 from rolling, 15 is an electric jack for adjusting the height of the pressure receiving jig 12, and 16 is to keep the end 11 of the arm 8 in contact with the pressure receiving jig 12 at all times. The pressure receiving jig 12, the electric jack 15, and the spring 16 adjust the roll interval and mechanically correct the zero point of the load cell 13.

Reference numeral 17 denotes a discharge chute provided with a vibrator 18. Although not shown, the fixed roll 6 and the movable roll 7 are provided with, for example, a metal brush or the like for removing pulverized matter attached to the roll surface. Further, as shown in the measurement principle diagram of FIG. Convert to

Next, the method of using the above-mentioned apparatus for measuring the pulverizability of the granular material will be described. First, coal left indoors was pulverized by a roll crusher and a disk pulverizer, and nine types of pulverizability measurement samples having a particle size of 1000 to 1190 μm were prepared by a vibrating sieve. The HGI of each of these samples was determined by the JIS method, and then 3 g of each sample was sampled, and the grindability was measured by the apparatus shown in FIG. The size of the fixed roll 6 and the movable roll 7 is set to 400 mm, the roll interval is set to 0.37 mm, and the number of rotations of the roll is set to 1 rpm. HGI was determined from the average stress integrated value of by the conversion formula. The output of the stress measuring device 13 at this time is as shown in FIG. 4, and the granular material is pulverized one by one between rolls.
It can be seen that the integrated value of the stress from the start of grinding to the end of grinding can be obtained individually. Thus, it was confirmed that there was a high correlation between the HGI determined by the method of the example and the HGI determined by the JIS method, as shown in FIG.

If the measurement conditions such as the particle size of the granular material, the roll interval, the number of rotations of the roll, the roll diameter, and the method of charging the sample are changed, the correlation shown in FIG. 3 is changed. The conversion formula may be corrected from the relational expression and input to the integral operation processing unit 20.

In the above embodiment, the measurement was carried out by dropping the granules one by one. However, before the pulverization of one granule was completed between the rolls, another granule was put between the rolls. You may. In this case, the output of the stress measuring device 13 is as shown in FIG. 5, but the same high correlation as in FIG. 3 can be obtained, and the value approximated to the HGI obtained by the JIS method is automatically calculated. Can be measured. In this case, it is necessary to keep the charging speed of the granular material constant. The granules for measurement do not need to be dried in advance, but the same high correlation as in FIG. 3 could be obtained even when the granules were dried.

In the above embodiment, the measured weight was 3 g. However, the larger the amount, the more preferable the standard deviation of the obtained HGI is. Table 1 shows the method of the present invention for coal particles when the sample to be measured is only one spherical granular material, when only one irregular-shaped granular material is used, and when it is composed of many granular materials. The standard deviation of HGI obtained from the above and the standard deviation of HGI obtained from the peak value are shown.

[0016]

[Table 1]

From Table 1 above, in the case of irregular shaped granules, the HGI obtained from the integrated value of the stress between the start and completion of the milling of the granules between the rolls is the peak value of the stress at the time of the milling. It is clear that the accuracy is much higher than the HGI obtained from Also, it can be seen that the greater the weight of the sample composed of a large number of granular materials for obtaining the magnitude of the average stress integrated value per unit weight, the higher the accuracy of the obtained HGI. When the granular material is nearly spherical, relatively high accuracy can be obtained even if the HGI is determined from the peak value of the stress during grinding.

Table 2 shows the relationship between the maximum value / minimum value of the particle size distribution of the sample granular material and the standard deviation of HGI. It can be seen that when the maximum / minimum value is 1.4 or less, a highly accurate HGI can be obtained irrespective of the average particle size of a sample composed of many granular materials.

[0019]

[Table 2]

Table 3 shows the relationship between the value of the average particle diameter / roll interval of the granular material to be sampled and the standard deviation of HGI. The granular material was 3 g, and the particle diameter was adjusted so that the value of Table 3 with respect to the roll interval dimension was obtained. From Table 3, it can be seen that high precision HGI can be obtained when the particle diameter is in the range of 1.4 to 10 times the roll interval size, more preferably in the range of 2.7 to 4.5 times.

[0021]

[Table 3]

In the above embodiment, as shown in FIG. 1, the movable roll 7 was attached to the tip of the L-shaped arm 8 and the end 11 of the arm 8 was provided with a stress measuring device 13. However, the movable roll 7 may be attached to the vertical arm 8 as in the second embodiment shown in FIG. 6, and a stress measuring device 13 may be provided on the upper part of the arm 8, and furthermore, the third embodiment shown in FIG. Like movable roll 7
Is slidably mounted on the rail 8a, and the movable roll 7
May be directly detected by the stress measuring device 13.

[0023]

As described above, the present invention can be easily automated, and can measure the crushability of granular materials such as coal in a very short time with high accuracy, and can be measured by the JIS method. A value almost consistent with the HGI obtained can be obtained quickly. Therefore, the grindability measuring device and the grindability measuring method of the granular material of the present invention are also suitable for measuring the grindability of the granular material, and what contributes to the development of industry as solving the conventional problems. It is extremely large.

[Brief description of the drawings]

FIG. 1 is a front view showing a first embodiment of the present invention.

FIG. 2 is an operation principle diagram of the device of the first embodiment.

FIG. 3 is a graph showing a result measured by the apparatus of the example.

FIG. 4 is an output diagram of a stress measuring device when granular materials are dropped one by one.

FIG. 5 is an output diagram of a stress measuring device when a granular material is continuously dropped.

FIG. 6 is an operation principle diagram of the device of the second embodiment.

FIG. 7 is an operation principle diagram of the device of the third embodiment.

[Explanation of symbols]

 Reference Signs List 1 frame 2 base 3 feeder 4 chute 5 axis 6 fixed roll 7 movable roll 8 L-shaped arm 9 axis 10 axis 11 end 12 pressure receiving jig 13 stress measuring instrument 14 support column for preventing roll 15 electric jack 16 spring 17 Discharge chute 18 Vibrator 19 Amplifier 20 Integral processing unit

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁶ , DB name) G01N 3/00-3/62

Claims (6)

(57) [Claims] A fixed roll and a movable roll are provided opposite to each other below a chute for supplying a granular material, a stress measuring device for detecting a force applied to the movable roll, and crushability is determined from an integrated value of the output. An apparatus for measuring the pulverizability of a granular material, comprising: 2. A method for measuring the stress of a granular material pulverized between a fixed roll and a movable roll rotating at a constant speed while supplying the granular material to a chute of the granular material pulverizability measuring device according to claim 1. A method for measuring the crushability of the granular material, wherein the crushability is obtained from the integrated value of the output of the stress measuring device. 3. The method according to claim 1, wherein a stress when one granular material is pulverized between the fixed roll and the movable roll is integrated over time from the start to the completion of the pulverization, and the pulverizability is obtained from the integrated value. Item 4. The method for measuring the pulverizability of a granular material according to Item 2. 4. The method according to claim 1, wherein a plurality of granules having a total weight of a predetermined weight are successively pulverized between a fixed roll and a movable roll, and the stress is integrated over the whole number. 3. The method for measuring the pulverizability of a granular material according to claim 2, wherein the pulverizability is determined. 5. The method according to claim 4, wherein the maximum value / minimum value of the particle size distribution of the granular material is 1.4 or less. 6. The method according to claim 2, wherein the size of the granules is 1.4 to 10 times the size of the gap between the fixed roll and the movable roll.