JPH039241A - Method for measuring bulk density of granule containing magnetic material - Google Patents

Abstract

PURPOSE:To automatically measure the bulk density of the granule containing the magnetic material on an on-line basis by finding the ratio of inductance values when different granules are charged in a winding coil. CONSTITUTION:A sample which is sampled is stored in a hopper 5 automatically from a process and while the discharge valve at the lower part of a detection coil 1 is closed, a charging panel 7 fitted to the discharge tube 6 of the hopper is opened under the command of a sequence controller 4, the sample is charged in the coil 1 through a hood 2; when the sample fills the coil, the valve 7 is closed with the signal of a scaling controller 9 and a value of inductance L1 of the coil 1 is read by an arithmetic unit 11 through a measuring circuit 10 and stored. Then at set time when the sample is charged exceeding the intermediate level of the hood 2, a value L2 of the coil 1 is read. Then the high density of the sample is found from L1 and L2 and supplied to a display device 12.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for measuring the bulk density of powder or granular material containing a magnetic material.

[Conventional technology]

Conventionally, the bulk density of a powder or granule is determined by an operator placing a sample of the powder or granule into a container with a certain volume, in excess or deficiency of the given volume (the bulk density of the entire sample and the mass of the container alone). Weigh the
The mass of the powder in the container was obtained from the difference in mass, and the mass was divided by the internal volume of the container.

In addition, as an online measurement method, a method has been proposed in which radiation is irradiated onto powder and granules, and the bulk density can be determined since the degree to which radiant energy is absorbed by the powder differs depending on the density of the granules. (Sensor Practical Handbook 9 Fuji Techno System Co., Ltd., p. 298-300).

[Problem to be solved by the invention]

However, in the above-mentioned method of placing a powder sample in a container with a fixed volume and measuring its mass, it is necessary to charge exactly the right amount into the container without pressing down on the powder or giving any vibration to the container. However, there is a problem in that it is extremely difficult to automate weighing under such conditions.

In addition, measurement methods using radiation require various health and safety controls when used because radiation is harmful to the human body, and the absorption rate of radiation varies depending on the composition of the substance to be measured. Therefore, there were problems such as differences in composition leading to errors.

This invention was made in view of these conventional problems, and the inductance when a granular material of known mass is charged into a winding coil and the inductance when a large amount of granular material is charged. The purpose of the present invention is to solve the above-mentioned problems by using a method of determining the ratio to the inductance.

[Means to solve the problem]

In order to achieve the above object, this invention charges a powder sample of a fixed mass containing a magnetic material into a winding coil, determines the inductance of the winding coil at that time, and then In this method, the inductance of the wire-wound coil is determined when a large amount of the powder sample is charged, and the bulk density of the powder sample is calculated from the ratio of the initial inductance to the subsequent inductance. .

[Effect]

When a material containing a magnetic material is inserted into a wire-wound coil, the inductance of the coil changes depending on its magnetic permeability. That is, the inductance changes depending on the mass of the magnetic material in the charged material and the strength of magnetic permeability caused by the properties of the magnetic material.

Now, if a sample containing a magnetic material is charged into a container in which a coil 1 is wound around a cylinder and a hood 2 is provided on top of the coil 1 as shown in Fig. 3, the sample will be charged as shown in Fig. 4. amount(
The inductance L of the coil 1 changes as V) increases. In the figure, a represents the volume when the sample reaches the middle level of the coil 1, b represents the level of the upper end of the coil 1, and C represents the volume when the sample reaches the middle level of the hood 2. When the sample reaches a certain level, the coil 1 will not be able to detect it.
The inductance does not change any further.

Now, the content of magnetic material in the sample is P, the mass of the sample is W,
Let the bulk density be ρ. Let Wl be the mass of the sample when it is near points a and b in Figure 4, and let L be the inductance of coil l at this time.

Approximately, L 1 = K + ・P−W, ・
...Represented by (1). Here, K1 is a constant.

Next, the inductance Lz of the coil 1 when the sample is loaded up to the middle level of the hood 2 is not affected by V in W=ρ・V, so it is approximately expressed as L z ”' K z ・P・ρ
......It is represented by (2). Here, K2 is a constant. Therefore, from equations (1) and (2), is derived, and if a constant mass is used as Wl, L+ and K2
By measuring , the bulk density ρ can be determined.

〔Example〕

Embodiments of the present invention will be described below with reference to FIG.

First, the sample automatically sampled from the process is
6i! Check that the sample discharge valve provided at the bottom of the zero-order detection coil 1 stored in the hopper 5 is in the closed state! After confirming this, the charging valve 7 attached to the discharge pipe 6 of the hopper 5 is opened according to a command from the sequence controller 4, and the sample is transferred to the hood 2.
It is inserted into the detection coil 1 through the. Here, the amount of sample charged is controlled to reach a constant mass by the weighing IIJ control device 9 which receives the signal from the weighing device 8, and when the mass reaches a constant mass, the amount of the sample charged is controlled by the sequence control device 4 according to the signal from the weighing control device 9. The charging valve 7 is closed. Then, the value of the inductance of the detection coil l at this time is read and stored by the arithmetic unit 11 through the measuring circuit 10.

The sequence controller 4 then opens the charging valve 7 again and closes the charging valve 7 when a preset time has been reached such that the sample has been loaded above the mid-level of the hood 2.

After that, the arithmetic unit 11 reads the inductance value L2 of the detection coil 1 again through the measuring circuit 10, and these two
The bulk density ρ of the sample is determined from the two inductance values LI and Lt as shown in equation (3) above, and the bulk density indicator 12
Output to. After that, the sequence control device 4 gives a command to open the sample loading valve 7 and sample discharge valve 3, and after discharging all the samples in the hopper 5, hood 2, and detection coil 1, both valves 7. Close and prepare for the next measurement.

FIG. 2 shows the relationship between the bulk density obtained by the method according to the invention as described above and the index approximately determined from the inductance ratio Lz/L. α of the index (LZ/LIXα) is a constant determined by a measuring device.

〔Effect of the invention〕

As explained above, according to the present invention, it is possible to automatically measure the bulk density of powder and granular materials containing magnetic materials online, which is dramatically more efficient than conventional methods, and also reduces radiation. Many benefits can be obtained, such as eliminating the need for various safety and health controls that would be required when using the system.

[Brief explanation of drawings]

Fig. 1 is a conceptual diagram of an embodiment according to the present invention, Fig. 2 is a diagram showing the relationship between the inductance ratio index and bulk density obtained by the embodiment, Fig. 3 is a conceptual diagram of a detection coil, and Fig. 4 4 is a diagram showing a change in inductance corresponding to the amount of a sample containing a magnetic material charged into the detection coil of FIG. 3. FIG. 1... Winding coil (detection coil).

Claims (1)

[Claims] (1) Load a fixed mass of powder sample containing a magnetic material into a winding coil, determine the inductance of the winding coil at that time, and then load a large amount of powder sample with the same composition as the above sample. Find the inductance of the wire-wound coil when it is connected,
A method for measuring the bulk density of a powder or granular material containing a magnetic material, characterized in that the bulk density of the powder or granular material sample is calculated based on a ratio between an initial inductance and a subsequent inductance.