JPS5954943A - Method for measuring amount of magnetic particle in fluid - Google Patents

Abstract

PURPOSE:To measure the amount of magnetic particles in a fluid, by piercing magnetic flux through a piezoelectric vibrator which is arranged in a fluid, attracting the magnetic particles, and measuring the natural oscillating frequency. CONSTITUTION:A piezoelectric vibrator 12 is fixed in a pipe 10, wherein a fluid including magnetic particles such as waste liquid is flowed. An electromagnet 14 is provided in a cover 16 in order to attract the magnetic particles on the surface of the piezoelectric vibrator. An exciting signal SM is supplied to an exciting power source circuit 22 from an operation control circuit 20, and the excitation of the electromagnet 14 is started. The natural oscillating frequency of the piezoelectric vibrator 12 is memorized. The natural oscillating frequency is changed in esponse to the amount of the magnetic particles attracted to the surface of the piezoelectric vibrator 12. The difference is computed by the operation control circuit 20. Thus the concentration of the magnetic particles included in the fluid is obtained and displayed on a display device 24.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for measuring the amount of magnetic particles contained in a fluid.・□It is important to measure the amount of magnetic particles contained in a fluid that can be magnetized in a magnetic field. For example, when removing magnetic suspended matter from wastewater using an electromagnetic filter to purify the wastewater, or when using an electromagnetic filter to remove iron powder from slurry to refine ceramic raw materials, etc. It is extremely effective in ensuring the quality of cleaning tube donation processing solutions. Furthermore, the same problem applies even when the fluid is gas, such as when removing magnetic dust contained in exhaust smoke.

However, conventional methods require a troublesome process of weighing magnetic particles trapped in fluids such as water, oil, and exhaust gas.

Therefore, according to the conventional measurement method, the number of questions and time required for measurement are wasted, and information representing the amount of magnetic flux in the fluid is lost. Because of the delay (U'), there has been a problem that the response may be delayed, especially in industrial processes.

This invention was made against the background of the above circumstances.
The purpose of the present invention is to provide a measuring method that can automatically and quickly measure the amount of magnetic particles contained in a fluid. shall be. :,
.

However, when a piezoelectric vibrator is disposed in a fluid, the piezoelectric □□actual□. 76. After adsorbing the magnetic particles in the fluid to a piezoelectric vibrator,

The natural frequency of the piezoelectric vibrator is detected, and the amount of magnetic particles contained in the fluid is calculated from a predetermined relationship between the natural frequency of the piezoelectric vibrator and the amount of magnetic particles contained in the fluid. The goal is to measure the amount of

In this way, the magnetized particles in the fluid are easily released into the fluid, so that the sampling work of magnetic particles and the cleaning work to remove the magnetic particles after measurement are completely eliminated. Furthermore, by detecting the natural frequency of the piezoelectric vibrator to which the magnetic particles are attracted, the amount of magnetic particles in the fluid is measured from a predetermined relationship, which requires tedious weighing work. do not. Therefore, the amount of magnetic particles in the fluid can be measured and determined automatically and quickly.

Hereinafter, one example of suitably implementing the method of the present invention will be explained.

In FIG. 1, a piezoelectric vibrator I2 (j1) is fixed in a pipe 10 through which a fluid containing magnetic particles such as waste liquid flows, and the magnetic particles are attracted to the surface of the piezoelectric vibrator 12. An electromagnet 14 is provided in a cover 16 fixed to the outside of the pipe 10.

The oscillation circuit 18 is connected to the electrodes of the piezoelectric vibrator 12, and oscillates at a frequency determined by the natural frequency of the piezoelectric vibrator 1.2, and also sends a signal SF of the snow frequency to the calculation control circuit 29. supply The arithmetic/control circuit 20 supplies an excitation signal SM to the excitation power supply circuit 22 at the start of a measurement cycle according to a pre-stored program, and at the same time causes the excitation power supply circuit 22 to supply constant excitation power to the electromagnet 14. Piezoelectric vibrator 1 at the start of measurement represented by signal SF
Then, when a certain period of time has elapsed from the start of the measurement cycle, the natural frequency of the piezoelectric vibrator 12 represented by the signal SF is stored, and from this, the amount of magnetic particles in the fluid is calculated. A signal S representing the amount of magnetic particles is determined.
C is output to the display device 24 to display the amount of magnetic particles.

FIG. 3 - As shown in detail, the piezoelectric vibrator 12 has a vibrating posture in which it performs bending vibration, and its center portion is attached to the fixed member 2.
6 is fixed to the inner wall surface of the pipe 10 so as to be able to vibrate. Then, the electromagnet I4 is fixed on the opposite side of the piezoelectric vibrator 1.2 by sandwiching the side wall of the pipe 10, and when the electromagnet 14 is excited, the electric flux formed by the electromagnet 14 is transferred to the piezoelectric vibrator 12. The magnetic particles in the fluid are absorbed onto the surface of both ends of the fluid by penetrating both ends (vibrating portions) of the fluid. That is, the electromagnet 14 consists of a coil 28 and its core 30, and the piping 10 of the core 30. On the side, pipes 10 are connected to both ends of the cloth vibrator 12. 3 chevron-shaped magnetic poles for concentrating magnetic flux are located opposite the wall.
2 is formed. Therefore, 5- magnetic flux is concentrated on the chevron-shaped magnetic pole 32, so much magnetic flux passes through both ends of the piezoelectric vibrator 120 near the chevron-shaped magnetic pole 32, and the magnetized magnetic particles are attracted in the direction of the magnetic flux, increasing efficiency. Magnetic particles are often attracted onto both ends of the material. Note that among the □ piping 10, at least the piezoelectric vibrator 12 and the core 30. The portion sandwiched between and the vicinity thereof is made of a so-called non-magnetic material such as copper, aluminum alloy, resin, etc. that can be magnetized very slightly, so that the magnetic flux is not short-circuited by the pipe 10.

In the apparatus configured as described above, at the same time that a measurement cycle is started by a timing signal (not shown), an excitation signal 8 is sent from the arithmetic control circuit 20 to the excitation power supply circuit 22.
M is supplied and excitation of the electromagnets 1 and 4 is started, and the natural frequency co of the piezoelectric vibrator 12 at this time is stored. Then, magnetic particles floating in the fluid begin to be attracted to the surface of the piezoelectric vibrator 12 according to the magnetic force of the electromagnet 14.

When a predetermined period of time has elapsed, the arithmetic and control circuit 20 stores the natural frequency f of the piezoelectric vibrator 12, and also records the natural frequency fo at the start of measurement and the elapsed period of time. The difference in frequency from the subsequent eigen-dynamic @f is calculated. Then, based on the difference in frequency, from the relationship between the magnetic particle concentration and the natural frequency difference D ('o f) shown in FIG.

A signal 8C representing the zero concentration of magnetic particles contained in the fluid is output to the display device 24, indicating the concentration of the magnetic particles, that is,
Since the natural vibration J of the piezoelectric vibrator 12 is reduced according to the mass of the magnetic particles adsorbed to it, a certain correspondence relationship between the natural frequency and the mass of the magnetic particles is determined in advance. Request and response □Relationship, relationship.

From this, the amount of magnetic particles is measured. It goes without saying that this correspondence relationship is determined for each type of magnetic particle. In addition, in the case of this embodiment, since the flow rate of the fluid that is constantly flowing into the pipe 10 is known in advance, the amount of magnetic particles contained in the fluid is equal to the concentration (amount of magnetic particles per unit volume). On the other hand, when the natural frequency "is detected after a certain period of time has elapsed after the start of the measurement cycle, the excitation signal SM output from the arithmetic control circuit 2.0 to the excitation power supply circuit 22 is stopped for a certain period of time. , the magnetic particles adsorbed on the piezoelectric vibrator 12 are released into the fluid and removed, and one measurement cycle is completed.

The above-mentioned measurement cycle is automatically repeated, and the amount of magnetic particles in the fluid can be measured quickly and continuously without the need for labor-intensive and time-consuming operations such as sampling, cleaning, and weighing. It is measured. Therefore, if the above measurement method is used in an industrial process, it is possible to quickly and continuously respond to the amount of magnetic particles in a fluid.

Hereinafter, an example in which the method of the present invention is implemented has been described based on the drawings, but the method of the present invention is also applicable to other embodiments.

For example, one or both ends of the piezoelectric vibrator 12 may be fixed in the pipe 10 by the fixing member 26, or the piezoelectric vibrator 12 may be disk-shaped and its outer periphery may be fixed to the fixing member. May be supported.

In the latter case, the vibration of the piezoelectric vibrator 12 is prevented from being affected by foreign matter entering the gap between the piezoelectric vibrator 12 and the pipe 10.

In the example described above, the natural frequency f
The amount of magnetic particles is measured by memorizing the natural frequency fo and calculating the difference between the natural frequency fo and the natural frequency after a certain period of time. From this relationship, the amount of magnetic particles can be measured only by the natural frequency f.

In the above-mentioned embodiment, the comparison piezoelectric vibration, the metal ring, the natural frequency fc of this comparative piezoelectric vibrator, and the piezoelectric vibrator 12
The amount of magnetic particles in the fluid may be determined by determining the difference between f and the natural frequency f after a certain period of time. In this case, if the piezoelectric vibrator for comparison has the same shape and mounting condition as the piezoelectric vibrator 12, and is placed in a position away from the electromagnet 14 in the piping 10, the effects of temperature and fluid viscosity on vibration can be compensated for. This has the advantage of providing high measurement accuracy.

It should be noted that the above-mentioned embodiment is merely one embodiment-9 of the present invention, and various modifications may be made to the present invention without departing from the spirit thereof.

Therefore, the sampling and cleaning work of magnetic particles can be completely eliminated, and by knowing the natural frequency of the piezoelectric vibrator to which the magnetic particles are adsorbed,
Since the amount of magnetic particles contained in the flow chair is determined from a certain relationship determined in advance, the amount of magnetic particles can be measured quickly and automatically without the need for troublesome weighing operations.

[Brief explanation of drawings]

FIG. 1 is a diagram illustrating the configuration of an apparatus in which the method of the present invention is implemented. FIG. 2 is a diagram showing a predetermined constant relationship used in the embodiment of FIG. 1. FIG. 3 is a diagram showing the main part of FIG. 1. 12: Piezoelectric vibrator 14: Electromagnet (magnet) 10-

Claims (1)

[Claims] A method for measuring the amount of magnetic particles contained in a fluid, comprising: arranging a piezoelectric vibrator in the fluid, and measuring magnetic flux passing through the piezoelectric vibrator. After the magnetic particles are attracted to the piezoelectric vibrator by a magnet forming a From the predetermined constant relationship with the quantity,
□Previous□A magnetic particle amount measurement method characterized by measuring the amount of magnetic particles contained in the fluid.