JP2000283828A - Level gage - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance an accuracy of measuring by providing a magnetic element- inserted detector in a cylinder in which a liquid can flow in and out, providing a magnet-embedded float on a liquid level of a periphery of the element in a point contact state, and calculating data from a twisting vibration of the element. SOLUTION: An outer cylinder 2 is disposed at a suitable space at an outside of an inner cylinder 1. Both the cylinders 1, 2 are all porous tubes. A rod-like magnetic element 3a for constituting a magnetostrictive line along a central axis in the cylinder 1 is inserted into a magnetostrictive detector 3. A magnet is embedded in a float 4, and the floats 4 of the number decided so that, when the floats 4 are floated in the cylinder 1, the floats 4 are brought into point contact with the element 3a as a center in a gap with the cylinder 1, are inserted in the cylinder 1. In the case of measuring a level of the river, water of the river at a level flows in and out of the cylinders 1, 2, and the floats 4 are floated at the level in the cylinder 1 centering around the element 3a in a point contact state. The detector 3 detects a twisting vibration of the element 3a from the magnets of the floats 4 by an axial magnetic field, and converts it into a signal. A calculator 5 calculates based on the signal to obtain level measured data.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid level gauge using a magnetostrictive detector.

[0002]

2. Description of the Related Art Conventionally, as a liquid level meter for measuring the water level of a river or measuring the liquid level of a liquid contained in a tank through which liquid can flow in and out, there is a liquid level gauge using a magnetostrictive detector.

FIG. 4 shows a configuration example of such a conventional liquid level gauge.

As shown in the figure, a magnetostriction detector 40 is provided on a central axis line in a cylindrical body 21 as shown in the figure, and a donut shape which moves up and down in accordance with a liquid level around the magnetostriction line of the magnetostriction detector 40. Is provided, and a magnet 23 is embedded in a peripheral surface of a hole provided in the center of the float 22.

When the magnetostrictive detector 40 gives a current pulse as shown by an arrow A to the magnetostrictive wire 41 as shown in FIG. 5, a magnetic field 42 in the circumferential direction is generated in the magnetostrictive wire 41. on the other hand,
When the magnet 43 is disposed near the magnetostrictive wire 41, the magnet 4
An axial magnetic field 44 is applied only to the portion where 3 is disposed, and an oblique magnetic field is generated in the magnetostrictive line 41 as shown by a broken line. Therefore, torsional waves are generated only in this portion of the magnetostrictive wire 41. This phenomenon is called the weedemann effect.

The instantaneous torsional vibration generated as described above propagates in the magnetostrictive wire at a constant speed as torsional mode ultrasonic waves 45 in the solid. By detecting the torsional vibration propagating in the magnetostrictive wire with a detection coil (not shown) provided at one end of the magnetostrictive wire 41, the time from the moment when the pulse current is supplied to the detection of the torsional vibration is converted to a voltage or current analog output. Alternatively, by outputting as a digital signal counted by the counter, the position with respect to the magnetostrictive line 41 can be detected. In this case, the time from the moment when the pulse current flows to the time when the torsional vibration is detected is proportional to the distance between the magnet 43 and the detection coil.

Therefore, by utilizing the principle of such a magnetostrictive detector, the position of the magnet 23 embedded in the donut-shaped float 22 which moves up and down according to the liquid level is detected, whereby the liquid level can be measured. It becomes possible.

[0008]

However, in a conventional liquid level meter using a magnetostrictive detector, a magnet 43 is buried in a peripheral surface of a hole formed in the center of a donut-shaped float 22 to form a magnetostrictive wire 41. To apply an axial magnetic field to the float 22
Since the device itself is moved up and down about the magnetostrictive wire 41, a gap is required between a hole provided at the center of the float 22 and the rod 40 a containing the magnetostrictive wire 41.

For this reason, when the liquid level gauge is used, for example, as a water level gauge for a river, if dust or the like enters the gap between the hole provided in the center of the float 22 and the rod 40a, the gap may become an eye. It becomes clogged and float 22
Cannot move up and down, making it impossible to measure the water level.

When the float 22 is used as a liquid level gauge for measuring the liquid level of a liquid contained in a tank capable of supplying and discharging the liquid, the float 22 is always set at the center of the magnetostrictive line 41 of the magnetostrictive detector 40. Magnetostrictive wire 4 in tank to move up and down
1 must be inserted vertically.

However, depending on the shape and structure of the tank,
Not only can the rod 40a of the magnetostriction detector 40 be inserted vertically but also some must be inserted obliquely downward. In such a case, the inclination of the rod 40a restricts the movement of the float 22. , The liquid level in the tank cannot be measured.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and is not affected by the liquid level measurement environment, and is capable of measuring the liquid level with high accuracy even when the applicable range is expanded. It is an object of the present invention to provide a liquid level gauge utilizing the method.

[0013]

According to the present invention, in order to achieve the above object, a plant operation training apparatus is constituted by the following means.

According to a first aspect of the present invention, there is provided a cylindrical body provided with a hole through which liquid can flow in and out, and a rod-shaped magnetic body forming a magnetostrictive line along the axial direction in the cylindrical body. The inserted magnetostrictive detector and the magnetic body in the cylinder are provided so as to be floated on the liquid surface of a peripheral portion centered on the magnetic body, and the portions that are in contact with each other are formed into a curved surface in a point contact or line contact state. A plurality of floats having magnets embedded therein, and the magnetostriction detector electrically detects the floating position of the float from torsional vibration of the magnetic body due to an axial magnetic field given by the magnet of the float, And arithmetic means for performing arithmetic processing on the data and outputting the result as liquid level measurement data.

According to a second aspect of the present invention, in the liquid level gauge according to the first aspect, the float is formed in a spherical shape.

According to a third aspect of the present invention, in the liquid level gauge according to the first aspect of the present invention, the cylinder is constituted by a perforated tube.

In the liquid level gauge according to the present invention, a plurality of floats each having a magnet embedded on the liquid surface in the cylinder constitute a magnetostrictive wire of the magnetostrictive detector. The magnetic body 3a and the float 4, which constitute a magnetostrictive line even when dust or the like enters the cylindrical body, are floated around the rod-shaped magnetic body so that they can move back and forth and left and right in point contact with each other. The liquid level can always be measured with high accuracy by the magnetostrictive detector without clogging during the period. In addition, the liquid level can be measured without installing a liquid level gauge so that the rod-shaped magnetic material constituting the magnetostrictive wire of the magnetostrictive detector is perpendicular to the liquid level, so that the applicable range can be expanded. it can.

[0018]

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

FIG. 1 is a sectional view showing a first embodiment of a liquid level gauge according to the present invention.

In FIG. 1, 1 is an inner cylinder, 2 is this inner cylinder 1
The inner cylinder 1 and the outer cylinder 2 are each constituted by a perforated tube.

Reference numeral 3 denotes a magnetostrictive detector in which a rod-shaped magnetic body 3a constituting a magnetostrictive line is inserted into the inner cylinder 1 along the center axis thereof. The principle of the magnetostrictive detector 3 is shown in FIG. Since this is the same as described above, the description is omitted here.

On the other hand, reference numeral 4 denotes a plurality of spherical floats floating on the liquid surface which penetrates into the inner cylinder 1, and when these floats 4 are floated on the liquid surface, the magnetostrictive lines of the magnetostrictive detector 3 Are inserted into the gap around the magnetic body 3a constituting the center and the inner peripheral surface of the inner cylinder 1 in such a number as to be in point contact with each other.

As shown in FIG. 2A, the float 4 is formed by covering a magnet 4a with a material having a specific gravity smaller than that of a liquid and transmitting magnetic lines of force, for example, a plastic material so as to be entirely spherical. is there.

The shape of the float 4 is not limited to a spherical shape, but may be a rhombic shape as shown in FIG. 2B, a cylindrical shape as shown in FIG. The shape may be elliptical as shown in FIG.

In this case, regardless of the shape, a curved surface is formed at least at a portion to be brought into contact with an adjacent float, and the position of the center of gravity is appropriately determined in consideration of the shape of the magnet 4a and the buried position. When the float is floated on the liquid surface, the float is brought into a point contact or a line contact state with the curved surface of the adjacent float.

In FIG. 2, the magnet 4a is buried inside the flow and inside. However, if the position of the center of gravity is determined in consideration of the buried position, a part of the magnet may be exposed.

Next, the operation of the liquid level meter thus configured will be described.

Now, consider a case where a liquid level gauge is installed as a water level gauge at an appropriate measuring point in a river to measure the water level of the river. Since the inner cylinder 1 and the outer cylinder 2 are constituted by perforated pipes, water flows into and out of each cylinder while maintaining a level corresponding to the river water level. At this time, a plurality of floats 4 are floating on the water surface in the inner cylinder 1 in a point contact state with each other about a rod-shaped magnetic body 3 a constituting the magnetostrictive line of the magnetostrictive detector 3.

In this case, each float 4 not only moves up and down according to the water level, but also alternately moves back and forth and right and left according to the flow of water. One of the floats 4 forms the magnetostrictive line of the magnetostrictive detector 3. In contact with the magnetic material 3a.

Therefore, the magnetostrictive detector 3 does not show torsional vibration generated by the axial magnetic field applied to the magnetic body 3a constituting the magnetostrictive wire from the magnet 4a embedded in the float 4 according to the principle described with reference to FIG. Water level measurement data can be obtained by detecting with a detection coil, converting this into an electric signal, and performing a predetermined calculation in the calculation unit 5 to obtain the position of the float.

As described above, in the first embodiment, the inner cylinder 1
Floats 4 with magnets 4a embedded on the water surface inside
Is a rod-shaped magnetic body 3 constituting the magnetostrictive wire of the magnetostrictive detector 3
The magnetic material 3a and the float 4 constituting the magnetostrictive wire even if dust or the like enters the inner cylinder 1 made of a perforated tube because the floating material 4 is floated up and down and left and right in a point contact state with each other around the center a.
The water level can always be measured with high accuracy by the magnetostrictive detector 3 without clogging between the two.

In the above-described embodiment, the case of a double configuration of the inner cylinder 1 and the outer cylinder 2 has been described assuming a water level gauge used in a river, but the magnetostriction detector 3 is provided in one cylinder. The configuration may be provided.

FIG. 3 is a sectional view showing a second embodiment of the liquid level gauge according to the present invention, and the same parts as those in FIG.

In FIG. 3, reference numeral 11 denotes a tank containing a liquid 12 such as petroleum therein.
Represents liquid 1 through a liquid supply port and a liquid discharge port (not shown).
2 can be supplied and discharged. The upper opening of the tank 11 is closed by a round lid 13.

The liquid level gauge is inserted into the tank 11 through a hole provided in a part of the periphery of the lid 13 at a slant downward. The liquid level gauge includes a cylindrical body 10 formed of a perforated tube, a magnetostrictive detector 3 in which a rod-shaped magnetic body 3a constituting a magnetostrictive line is inserted along the center axis of the cylindrical body 10,
A plurality of spherical floats 4 floating above the liquid surface that enters the cylindrical body 10 are provided.

Here, the principle of the magnetostriction detector 3 is the same as that described with reference to FIG. 5, and the description is omitted here. The float 4 may have a shape shown in any of FIGS. 2A to 2D. However, when any of the floats floats on the liquid surface in the same manner as described above, the The contact portion with the floating float is formed on a curved surface in a point contact or line contact state.

In the liquid level gauge inserted into the tank 11 in such a state, in order to measure the liquid level, a magnetostrictive line is formed from the magnet 4a embedded in the float 4 as in the first embodiment. The torsional vibration generated by the axial magnetic field applied to the magnetic body 3a is detected by a detection coil (not shown), converted into an electric signal, and input to the arithmetic unit 5.

The arithmetic unit 5 receives a predetermined angle based on the angle of the liquid level gauge inserted into the tank 11 with respect to the liquid level and the distance data from the bottom of the tank 11 to the lower end of the cylinder 10. The liquid level measurement data can be obtained by calculating the float position by executing the calculation.

As described above, in the second embodiment, even when the liquid level gauge is inserted obliquely downward into the tank 11, the plurality of floats 4 having the magnets 4a embedded on the liquid level in the cylindrical body 10 are formed. Are floated so as to be able to move up and down in a state of point contact with each other about the magnetostrictive wire 3a of the magnetostrictive detector 3, so that the movement of the float 22 is not restricted by the inclination of the magnetostrictive wire 41.
The liquid level in the tank can always be measured with high accuracy.

[0040]

As described above, according to the present invention, a magnetostrictive detector which can measure a liquid level with high accuracy without being influenced by a liquid level measuring environment and which can be applied even when an application range is expanded. A liquid level gauge can be provided.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a first embodiment of a liquid level gauge according to the present invention.

FIGS. 2A to 2D are views showing floats having different shapes according to the embodiment; FIGS.

FIG. 3 is a sectional view showing a second embodiment of the liquid level gauge according to the present invention.

FIG. 4 is a sectional view showing a configuration of a liquid level gauge using a conventional magnetostriction detector.

FIG. 5 is a diagram illustrating the principle of a magnetostriction detector.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Inner cylinder 2 ... Outer cylinder 3 ... Magnetostrictive detector 3a ... Magnetostrictive wire 4 ... Float 4a ... Magnet 5 ... Calculation part 10 ... Cylindrical body 11 ... Tank 13 ... Lid

Claims (3)

[Claims] 1. A cylinder provided with a hole through which a liquid can flow in and out, and a magnetostriction detector having a rod-shaped magnetic material constituting a magnetostrictive line inserted in the cylinder along an axial direction thereof. ,
It is provided floating on the liquid surface of the peripheral part around the magnetic body in the cylindrical body, and the parts that come into contact with each other are formed into a curved surface that is in a point contact or line contact state, and the magnet is embedded. The float position of the float is electrically detected from the plurality of floats and the torsional vibration of the magnetic body due to the axial magnetic field given by the magnet of the float by the magnetostriction detector, and the floating position is arithmetically processed to measure the liquid level. A liquid level meter comprising: a calculation means for outputting data as data. 2. The liquid level gauge according to claim 1, wherein said float is formed in a spherical shape. 3. The liquid level gauge according to claim 1, wherein said cylindrical body is constituted by a perforated tube.