JP2006317251A - Device for measuring magnetic material concentration - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To perform self-compensation of a zero point against a disturbance; to detect a magnetic material concentration continuously in a maintenance-free state; and to discharge easily and surely a solid material such as the magnetic material deposited near a coil. <P>SOLUTION: This device is provided with oscillation circuits 11, 12 equipped with coils 9, 10 wherein, when detecting a frequency by one oscillation circuit 11, 12 in the covered state by a rotator 7 so as not to be affected by a fluid 2, an oscillation frequency is detected by the other oscillation circuit 11, 12 in the uncovered state by the rotator 7 so as to be affected by the fluid; a superposing circuit 13 for determining the frequency difference between each frequency detected by both oscillation circuits 11, 12; an F/V converter 14 for determining the peak difference of the frequency difference from the frequency difference of the preceding time and the frequency difference of this time from the superposing circuit 13; and a signal processing circuit 15 for determining the magnetic material concentration from the peak difference determined by the F/V converter 14. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a magnetic substance concentration measuring apparatus.

  For example, in a prime mover such as an engine having a reciprocating component such as a piston, the piston and the cylinder are worn by sliding between the piston and the cylinder, and a magnetic material such as iron powder is generated. Thus, when such a magnetic material is generated, the magnetic material flows along with the oil flowing through the piping from the engine, so the concentration of the magnetic material contained in the fluid in the piping is measured appropriately. Therefore, it is necessary to accurately grasp the wear state of the equipment.

  Patent Documents 1 and 2 are prior art documents that measure the concentration of a magnetic substance accompanying a fluid such as oil. Patent Document 1 discloses a reference signal generation circuit that outputs a reference signal having a constant frequency, a detection signal generation circuit that outputs a frequency as a detection signal, a reference signal from the reference signal generation circuit, and a detection signal from the detection signal generation circuit. A signal processing circuit that outputs an electric signal including the difference frequency signal is provided, and the concentration of the magnetic substance is detected by a change in the electric signal including the frequency.

In Patent Document 2, the iron content of the used lubricant is continuously monitored, the actual wear amount to be compared with the allowable wear amount is specified based on the iron content, and the actual wear amount exceeds the allowable wear amount. In the event of an alarm, an alarm is issued.
Registered Utility Model No. 2579413 JP 2002-276323 A

  The techniques of Patent Documents 1 and 2 measure the concentration of magnetic material in a stable measurement environment with little change in temperature and vibration, and in the environment where there is no need to consider the accumulation of solid materials such as magnetic material in the measuring device. Is possible. However, in order to continuously and highly sensitively measure the magnetic substance concentration in a fluid such as drain oil that has flowed out of the device, irregular vibrations of the device, rapid temperature changes, solid deposits in the fluid, It is necessary for the magnetic substance concentration measuring device to have a function of self-compensating the zero point against disturbances such as regular electromagnetic noise and unstable fluid flow rate and discharging solid substances such as magnetic substances.

  However, in Patent Document 1, when the temperature change of a device or the like is large, a difference in temperature change occurs between the reference signal generation circuit and the detection signal generation circuit, the zero point shifts, and due to irregular vibration of the device The zero point is also shifted, and furthermore, the zero point is also shifted by the aging of each part. However, since there is no means for correcting the zero point, the zero point cannot be corrected.

  In addition, since there is no correction means for shifting the zero point due to the aging of each part, it is difficult to detect the magnetic substance concentration continuously without maintenance over a long period of time.

  Further, when a solid substance such as a magnetic substance accumulates in the vicinity of the detection signal generating circuit, since there is no means for removing the solid substance, the detection accuracy is high and the magnetic substance concentration cannot be detected accurately.

  In view of the above circumstances, the present invention can self-compensate the zero point for various disturbances, enables maintenance-free continuous detection of the magnetic substance concentration over a long period of time, and deposits in the vicinity of the coil. It is an object of the present invention to provide a magnetic substance concentration measuring apparatus that can easily and surely discharge a solid substance such as a magnetic substance.

  In the magnetic substance concentration measuring device of the present invention, when the frequency is detected by making the shielding body that blocks the flow of the fluid face the coil with one oscillation circuit, the shielding body faces the coil in the other oscillation circuit. The frequency is detected from the difference between the previous frequency and the current frequency obtained by the two oscillation circuits and the means for obtaining the difference between the frequencies detected by the two oscillation circuits. Means for obtaining the difference between the difference peaks and means for obtaining the magnetic substance concentration from the difference in the frequency difference peaks obtained by the means are provided.

  Further, in the magnetic substance concentration measuring apparatus of the present invention, when the frequency is detected by positioning the shielding body that blocks the flow of fluid in the coil by one oscillation circuit, the other oscillation circuit causes the shielding body to Two oscillation circuits that detect the frequency without being located in the coil, means for obtaining the difference between the frequencies detected by both oscillation circuits, the difference between the previous frequency obtained by the means and the current frequency Means for obtaining a peak difference of the frequency difference from the difference and means for obtaining the magnetic substance concentration from the difference of the peak of the frequency difference obtained by the means are provided.

  In the magnetic substance concentration measuring apparatus of the present invention, the shield is an eccentric rotating body installed in the fluid circulation space, and the shield is a rectilinear body installed in the fluid circulation space, The shielding body is a non-magnetic body, and the driving source of the shielding body is a means that does not use electromagnetic force. By driving the shielding body, solid matter deposited in the vicinity of the coil in the fluid circulation space is discharged. It is configured.

  In the present invention, the frequency is detected with one oscillating circuit facing the coil, or positioned in the coil, and the other oscillating circuit does not face the coil with the shielding. Alternatively, the frequency is detected without positioning the shield in the coil, and then the frequency difference is obtained. Subsequently, the difference between the previous frequency difference and the current frequency difference is the peak difference of the frequency difference. The magnetic substance concentration is obtained from the peak difference of the frequency difference.

According to the magnetic substance concentration measuring apparatus according to claims 1 to 7 of the present invention, various excellent effects can be obtained as follows.
I) By measuring the peak difference between the previous frequency difference and the current frequency difference, the difference between the two measurement results affected by disturbances such as magnetic noise, electromagnetic wave noise, temperature change, and electrical noise. Therefore, the disturbance is canceled out and the zero point is automatically corrected. Therefore, even when the zero point is shifted, self-correction can be performed.
II) By rotating or reciprocating linearly moving the shield, it is possible to eliminate the accumulation of solid substances such as a magnetic substance that is close to the coil in the fluid circulation space.
III) As described above, the magnetic substance concentration can be continuously measured with high accuracy even in a severe environment with disturbance.

Embodiments of the present invention will be described below with reference to the accompanying drawings.
FIGS. 1-10 is the 1st example of the form which implements this invention. In FIG. 1, 1 is a conduit through which drain oil 2 from a prime mover such as an engine flows, 3 is a conduit branched from a middle portion of the conduit 1, and 4 is a magnetic body provided at the lower end of the conduit 3. Two chambers 5 and 5 for detecting the concentration are connected to the lower end of the chamber 4 and connected to the downstream side in the drain oil flow direction of the connecting portion of the conduit 3 in the conduit 1. It is. Thus, the chamber 4 has a cylindrical shape on the side surface, and the ducts 3 and 5 are provided so as to face the tangential direction with respect to the outer periphery of the chamber 4.

  As shown in FIG. 2, each chamber 4 is provided with a shaft 6 that can be driven through the chamber 4 in the axial direction of the cylinder, and is fixed to the shaft 6 in each chamber 4. The rotating body 7 is accommodated. The shaft 6 and the rotating body 7 are nonmagnetic materials, and the rotating body 7 is eccentric with respect to the shaft 6. For the rotation of the shaft 6 and the rotating body 7, a driving source that does not use electromagnetic force, such as a motor using air pressure, hydraulic pressure, or ultrasonic waves, is used. As described above, the reason why the drive source that does not use electromagnetic force is used is that if a drive source that uses electromagnetic force such as an electric motor is used, the coil described later is affected, and the detection accuracy of the magnetic substance concentration is lowered. It is.

  In the gap 8 formed between the left and right chambers 4, coils 9 and 10 are arranged on the top and bottom with respect to the shaft 6, and oscillation circuits 11 and 12 are connected to the coils 9 and 10. ing.

  The rotating body 7 and the coils 9 and 10 are such that when the rotating body 7 rotates and the side with a large amount of eccentricity with respect to the shaft 6 is positioned downward as shown by the solid line in FIGS. It faces the coil 10 and does not face the coil 9, and the rotating body 7 rotates, and the side with a large eccentricity with respect to the shaft 6 is positioned upward as shown by the phantom lines in FIGS. 1 and 2. In this case, the rotating body 7 is formed to face the coil 9 and not to face the coil 10. Thus, on the side where the rotating body 7 is located in the chamber 4, the fluid 2 is prevented from flowing by the rotating body 7, and the fluid 2 in the chamber 4 is a portion where the rotating body 7 is not located. Has been distributed.

  The oscillation waves W1 and W2 having the frequencies f1 and f2 from the oscillation circuits 11 and 12 are respectively supplied to the superposition circuit 13. The superposition circuit 13 transmits the oscillation waves by superimposing the oscillation waves W1 and W2. The difference between the frequencies f1 and f2 | f1-f2 | (the beat period due to the resonance phenomenon of the oscillation waves W1 and W2) is obtained, and the data signal D1 of the rectangular wave W3 obtained by converting the beat period is output. It has become. Thus, the coils 9, 10, the oscillation circuits 11, 12, and the superposition circuit 13 form a heterodyne oscillation circuit.

  The data signal D1 of the rectangular wave W3 from the superposition circuit 13 can be given to an F / V converter (frequency-voltage converter) 14 that converts a frequency into a voltage signal, and is smoothed by the F / V converter 14. Thus, it is converted into a DC voltage corresponding to the frequency. In the F / V converter 14, the peak difference voltage signal Δf between the DC voltage when the rotating body 7 faces the coil 9 and the DC voltage when the rotating body 7 faces the coil 10 is obtained. The difference voltage signal Δf can be obtained and supplied to the signal processing circuit 15 as the detection value D2. Further, the signal processing circuit 15 can obtain the magnetic substance concentration from the detected value D2 of the difference signal data.

Next, the operation of the above-described embodiment will be described with reference to FIGS.
Part of the drain oil 2 discharged from the prime mover and fed to the pipeline 1 is introduced from the pipeline 1 to the pipeline 3, returns to the pipeline 1 from the pipeline 5 through the chamber 4, and enters the pipeline 3. It joins with the drain oil 2 that has not been introduced and is fed downstream. Thus, when measuring the concentration of the magnetic substance contained in the drain oil 2, the rotating body 7 is rotated via the shaft 6 by a driving source (not shown). , 10 are alternately opposed to the left and right rotating bodies 7 at regular intervals, and the coils 9, 10 facing the rotating body 7 are not affected by the magnetic body, and the coils 10 not facing the rotating body 7. , 9 are affected by the magnetic material. Further, by the rotation of the rotating body 7, the solid matter such as a magnetic body deposited in the vicinity of the coils 9 and 10 is removed and fed together with the drain oil 2 and the downstream pipe 5.

  1 and 2, when the rotating body 7 faces the coil 10 and does not face the coil 9, the drain oil 2 flows in the chamber 4 through the vicinity of the coil 9. The influence of the magnetic substance contained in the drain oil 2 is given from the coil 9 to the oscillation circuit 11, and from the oscillation circuit 11, the influence of the magnetic substance is included, and magnetic noise, electromagnetic wave noise, temperature change, electrical An oscillation wave W1 having a frequency f1 including disturbances such as noise is oscillated and applied to the superposition circuit 13 (see FIG. 3). At the same time, the oscillation circuit 12 oscillates an oscillation wave W2 having a frequency f2 that does not include the influence of a magnetic substance and includes disturbances such as magnetic noise, electromagnetic wave noise, temperature change, and electrical noise, and is a superposition circuit. 13 (see FIG. 4).

  In the superposition circuit 13, the oscillation waves W 1 and W 2 having the frequencies f 1 and f 2 are superposed to each other, whereby the difference between the frequencies f 1 and f 2 | f 1 −f 2 | (the period of beat due to the resonance phenomenon of both oscillation waves) 5) is obtained, and the period of beat is converted to obtain a rectangular wave W4 (see FIG. 6). The rectangular wave W4 is supplied to the F / V converter 14 and smoothed, and the frequency difference | f1− It is converted into a DC signal V (see FIG. 7) corresponding to f2 |. Note that the voltage increases as the frequency difference | f1-f2 | increases.

  Similarly, when the rotating body 7 rotates and the rotating body 7 faces the coil 9 and does not face the coil 10 as shown by the phantom lines in FIGS. 1 and 2, the drain oil 2 flows into the chamber 4. Since it flows through the position near the coil 10 inside, the influence of the magnetic substance contained in the drain oil 2 is given from the coil 10 to the oscillation circuit 12, and from the oscillation circuit 12, the influence of the magnetic substance is included. An oscillation wave W2 having a frequency f2 including disturbances such as magnetic noise, electromagnetic wave noise, temperature change, and electrical noise is oscillated and applied to the superposition circuit 13 (see FIG. 4). At the same time, the oscillation circuit 11 oscillates an oscillating wave W1 having a frequency f1 that does not include the influence of a magnetic substance and includes disturbances such as magnetic noise, electromagnetic wave noise, temperature change, and electrical noise. 13 (see FIG. 3).

  In the superposition circuit 13, the difference between the frequencies f 1 and f 2 | f 1 −f 2 | Waveform W3 (see FIG. 5) is obtained, and the beat cycle is converted to obtain a rectangular wave W4 (see FIG. 6). The rectangular wave W4 is given to the F / V converter 14. Smoothed and converted to a DC signal V (see FIG. 7) corresponding to the frequency difference | f1-f2 |.

  In the F / V converter 14, the difference | f 1 −f 2 | between the frequencies f 1 and f 2 when the rotating body 7 faces the coil 10 and the frequency f 1 when the rotating body 7 faces the coil 9. , F2 difference | f1−f2 | is obtained as a difference in peak | f1−f2 | − | f1−f2 | = Δf (see FIG. 8). And is supplied to the signal processing circuit 15 as the detection value D2. Note that | f1-f2 | in the previous absolute value symbol of | f1-f2 |-| f1-f2 | and | f1-f2 | in the subsequent absolute value symbol are the coil 9 facing the rotating body 7. , 10 are different from each other, and the specific numerical values are different.

  The chart of FIG. 8 is shown by shortening the time axis which is the horizontal axis, and the upper dotted line A indicates the frequency difference | f1-f2 | when the rotating body 7 faces the coil 9. The lower dotted line B shows the frequency difference | f1-f2 | when the rotating body 7 faces the coil 10. Further, X1, X2, X3... Xn indicate peaks of the frequency difference | f1-f2 | when the rotating body 7 faces the coil 9, and Y1, Y2, Y3. The peak of the frequency difference | f1−f2 | when the body 7 faces the coil 10 is shown.

  Further, since the relationship between the detection value D2 and the magnetic substance concentration has been clarified in advance (see FIG. 9), the signal processing circuit 15 obtains the magnetic substance concentration C (see FIG. 10) based on the detection value D2. The magnetic substance concentration C is sent to and displayed on a magnetic substance concentration display (not shown). The magnetic substance concentration C shown in the graph of FIG. 10 shows a case where the change with time is small.

  In the illustrated example, the rotating body 7 is rotated so that the rotating body 7 is alternately opposed to the coils 9 and 10 and is not opposed to the coils 10 and 9. Therefore, the difference | f1-f2 | between the frequencies f1 and f2 repeats the magnitude. As a result, disturbances such as magnetic noise, electromagnetic wave noise, temperature change, and electrical noise are measured by measuring a change in the difference | f1-f2 | between the frequencies f1 and f2 as a peak difference (variation Δf in FIG. 8). Thus, the difference between the two measurement results that are affected by is compensated for the disturbance, and the zero point is automatically corrected (self-correction). Therefore, even when the zero point is shifted, self-correction can be performed. Further, by rotating the rotating body 7, it is possible to eliminate the accumulation of solid substances such as magnetic bodies in the vicinity of the coils 9 and 10. Thereby, the magnetic substance concentration can be continuously measured with high accuracy even in a severe environment with the above-mentioned disturbance, and the concentration of the magnetic substance of the drain oil of the equipment such as the prime mover can be measured.

  11 and 12 show a second example of an embodiment for carrying out the present invention. In the illustrated example, the extension of the axis of the pipes 3 and 5 passes through the center of the chamber 4 and the embodiment shown in FIGS. 1 and 2 except that the number of the rotating bodies 7 is one. The configuration is the same as the example. In the figure, the same reference numerals as those shown in FIGS. 1 and 2 are given the same reference numerals. Thus, even with such a configuration, the magnetic substance concentration can be obtained in the same manner as in the case shown in FIGS. 1 and 2, and the same operational effects as in the examples of FIGS. 1 and 2 can be obtained.

  FIG. 13 shows a third example of an embodiment for carrying out the present invention. In the first example and the second example of the embodiment, by rotating the rotating body 7, the coils 9 and 10 which are affected by the magnetic body contained in the drain oil 2 and the coils 10 and 9 which are not received are alternately arranged. In the illustrated example, the linearly moving body 17 is moved up and down with respect to the inside of the pipe line 18 around which the coils 9 and 10 are wound by the actuator 16 such as a fluid pressure cylinder. The coils 9 and 10 that are affected by the magnetic material and the coils 10 and 9 that are not affected are alternately selected by the rectilinear body 17.

  In the figure, 19 is a pipeline through which drain oil 2 to be introduced into the pipeline 18 is fed, 20 is introduced with drain oil 2 from the pipeline 19, and the pipeline 19 and the pipeline 18 communicate with each other. As described above, a casing 21 having a retracting gap 20a in which the rectilinear body 17 ascends is a conduit for discharging the drain oil 2 that is connected through the joint 22 and discharged from the conduit 18. In addition, the circuit for measuring the magnetic substance concentration is the same as the first example and the second example of the embodiment, and in the figure, the same reference numerals as shown in FIGS. 1, 2, 11, and 12 are used. Are given the same reference numerals.

  In the illustrated example, when the coil 9 is not affected by the magnetic material and the coil 10 is affected by the magnetic material, the rectilinear body 17 is brought into a state of being inserted into the coil 9. When the magnetic material is not affected to the coil 10 and the magnetic material is affected to the coil 9, the linearly moving body 17 is in a state as inserted into the coil 10. Thus, also in the illustrated example, the magnetic substance concentration can be measured in the same manner as in the first and second examples of the embodiment, and the same effect can be obtained.

  In the magnetic substance concentration measuring device of the present invention, the rotating body 7 can be continuously rotated or intermittently rotated so as to stop at a position facing the coils 9 and 10. In addition, the rectilinear body 17 may be continuously reciprocated so as not to stop at the positions of the coils 9 and 10 or may be intermittently reciprocated so as to stop at the positions of the coils 9 and 10. Of course, various changes can be made without departing from the scope of the present invention.

It is a sectional side view of the 1st example of embodiment of the magnetic substance concentration measuring apparatus of this invention. It is an II-II direction arrow line view of FIG. It is a chart which shows the oscillation wave of frequency f1. It is a chart which shows the oscillation wave of frequency f2. It is a graph which shows the waveform obtained by superimposing the oscillation wave of frequency f1, f2. 6 is a chart showing a rectangular wave obtained by converting the waveform of FIG. 5. It is the chart which converted the difference of the frequency obtained by smoothing a rectangular wave into a direct current signal. It is a graph which shows the difference of the peak of the difference of the frequency obtained by the difference of the coil which a rotary body opposes. It is a graph which shows the relationship between a detected value and a magnetic body density | concentration. It is a graph which shows the state of a change with time of a magnetic body concentration. It is a sectional side view of the 2nd example of an embodiment of a magnetic substance concentration measuring device of the present invention. It is a XII-XII direction arrow directional view of FIG. It is a sectional side view of the 3rd example of embodiment of the magnetic substance concentration measuring apparatus of this invention.

Explanation of symbols

4 rooms (fluid distribution space)
5 pipeline (fluid distribution space)
7 Rotating body (shield)
9 Coil 10 Coil 11 Oscillation circuit 12 Oscillation circuit 13 Overlay circuit (means)
14 F / V converter (means)
15 Signal processing circuit (means)
17 Straight body (shield)
18 Pipeline (fluid distribution space)
C Magnetic substance concentration f1 Frequency f2 Frequency Δf Fluctuation (Frequency difference peak difference)

Claims (7)

  In one oscillation circuit, when the frequency is detected by making the shield that blocks the flow of fluid face the coil, the other oscillation circuit detects the frequency without making the shield face the coil. , Two oscillation circuits, a means for obtaining a difference between the frequencies detected by both oscillation circuits, a means for obtaining a difference between the previous frequency difference obtained by the means and a difference between the current frequency and a peak difference of the frequency difference; A magnetic substance concentration measuring apparatus comprising means for obtaining a magnetic substance concentration from a difference in peak of a frequency difference obtained by said means.   When one of the oscillation circuits detects a frequency by positioning a shield that blocks the flow of fluid in the coil, the other oscillation circuit detects the frequency without positioning the shield in the coil. The two oscillation circuits, means for obtaining the difference between the frequencies detected by the two oscillation circuits, and means for obtaining the peak difference of the frequency difference from the previous frequency difference obtained by the means and the current frequency difference And a magnetic substance concentration measuring device comprising means for obtaining a magnetic substance concentration from a difference in peaks of frequency differences obtained by the means.   The magnetic substance concentration measuring apparatus according to claim 1, wherein the shield is an eccentric rotating body installed in the fluid circulation space.   3. The magnetic substance concentration measuring apparatus according to claim 2, wherein the shield is a straight body installed in the fluid circulation space.   The magnetic substance concentration measuring apparatus according to claim 1, wherein the shield is a non-magnetic substance.   6. The magnetic substance concentration measuring apparatus according to claim 1, wherein the driving source of the shield is a means that does not use electromagnetic force.   The magnetic substance concentration measuring device according to any one of claims 1 to 6, wherein solid substances deposited close to the coil in the fluid circulation space are discharged by driving the shield.

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