JP3132586B2 - Vibration level detector - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vibrating level detecting device provided for detecting a change in the level of a granular material or a liquid contained in a container or the like.

[0002]

2. Description of the Related Art FIG. 6 is a side sectional view showing a state in which a conventional vibration type level detecting device is fixed to a container 6 containing an object to be detected. The vibrating level detecting device includes a sensing unit that protrudes from a main body 50 of the vibrating level detecting device to a granular material, a liquid, or the like, which is a detection target stored in the container 6.
22a are configured to make contact. The sensing unit 22a is composed of a rod-shaped vibrating body 22 together with a detecting unit 22b housed inside the cylindrical portion 24 of the main body 50, and the vibrating body 22 has a protruding end of the cylindrical portion 24 substantially at the center. Membrane plate provided in the section
Supported by 23. The membrane plate 23 is provided so as to close the projecting end of the cylindrical portion 24 projecting into the container 6. This vibration type level detecting device is fixed to the container 6 containing the object to be detected by screwing a nut 25 into a threaded portion 24a formed in the cylindrical portion 24.

[0003] A piezoelectric element 26 for excitation and a piezoelectric element 27 for vibration reception are provided on a detection part 22 b of the vibrating body 22. The excitation piezoelectric element 26 vibrates the vibrating body 22, and the vibration receiving piezoelectric element 27 converts a vibration state of the vibrating body 22 by the excitation piezoelectric element 26 into an electric signal. This electric signal is amplified by an amplifier circuit housed in the main body 50, and then applied to the excitation piezoelectric element 26 via an output circuit. In this way, the vibrating body 22 is configured so that the vibration continues at the natural frequency.

[0004] When a granular material or the like to be detected comes into contact with the sensing portion 22a of the vibrating body 22 and resistance is given to the vibration of the vibrating body 22, the vibration of the sensing portion 22a is attenuated or stopped. The vibration state of the sensing unit 22a is converted into an electric signal by the vibration receiving piezoelectric element 27 attached to the detection unit 22b, and is detected by a detection circuit provided in the main body 50. In this manner, the conventional vibration-type level detection device detects a change in the vibration state of the detection unit 22b and determines whether or not the detection target exists around the sensing unit 22a of the vibration-type level detection device. It is to detect.

[0005]

As described above, in the conventional vibration type level detecting device, whether or not an object to be detected has reached a predetermined level is disposed inside the cylindrical portion 24 of the main body 50. The detection unit 22b detects the change based on the change in the vibration state of the detection unit 22b.
It is based on the premise that the vibration mode of a changes in the same manner as the vibration mode of the detection unit 22b.

However, when the granular material or the like is firmly filled with a large pressure and the vibration of the sensing unit 22a is strongly restrained by the granular material or the like to be detected and is forcibly stopped, the vibration member 22 In some cases, only the detection unit 22b does not stop and causes self-excited vibration. For this reason, the conventional vibration type level detection device may output erroneous data that the detected object has not reached the predetermined level even though the detected object is in contact with the sensing unit 22a. there were. SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned problems and to provide a vibration-type level detection device which has high detection accuracy and can handle various containers and is easy to handle.

[0007]

A vibration type level detecting apparatus according to the present invention comprises a base fixed to the outside of a container or the like for accommodating an object to be detected, and an obstruction led out from the base to the inside of the container or the like. A vibrating body having a substantially central portion supported by the portion, wherein an inner portion disposed inside the closed portion is formed in a flat plate shape, and an outer portion protruding from the cylindrical portion is substantially formed. A vibrating body formed in a cylindrical shape, vibrating means provided on an inner portion of the vibrating body, and vibrating means for vibrating the vibrating body; and a vibrating body provided on a distal end of an outer portion of the vibrating body. Vibration detecting means for detecting the state.

[0008]

According to the vibration level detecting device of the present invention, a diaphragm supported by the tip of a closed portion protruding into a container or the like for storing an object to be detected is disposed inside the closed portion of the vibrating plate. The vibrating unit provided in the vibrating unit vibrates. When the object to be detected comes into contact with the sensing part disposed outside the closed part of the diaphragm, the vibration at the tip of the sensing part of the diaphragm is attenuated or stopped, and the change of attenuation or stop of the vibration is detected by the diaphragm. It is detected by vibration detection means provided at the tip of the section, for example, an acceleration sensing element.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the vibration type level detecting device according to the present invention will be described with reference to the drawings. FIG. 1 is a side sectional view of a vibration type level detecting device according to an embodiment of the present invention, FIG. 2 is a plan sectional view of the vibration type level detecting device of FIG. 1, and FIG. FIG. 4 is a side sectional view showing the vicinity of the body 2, FIG. 4 is a plan sectional view showing the vicinity of the vibrating body 2 of FIG. 3, and FIG. 5 is a block diagram of an electric circuit in the vibration level detecting device of FIG.

As shown in FIG. 1, the vibration type level detecting device of the present embodiment is attached to a container 6 for storing a granular material, a liquid, or the like as an object to be detected, and is disposed outside the container 6. It has a base 1 and a cylindrical portion 4 protruding into the container 6. The base 1 houses a weight 7 which is a heavy object for stabilizing vibration of the vibrating body 2 described later, a printed circuit board 15 having an electric circuit and the like for driving the vibrating level detecting device, and the like. ing. The base 1 is formed with a mounting screw portion 1a for mounting to a container 6 in which an object to be detected is stored, and the vibration type level detector uses a nut 5 screwed to the mounting screw portion 1a to rotate the container. 6 is fixed via a packing and a washer. The tubular portion 4 protruding from the base 1 to the inside of the container 6 is formed in a pipe shape, and a closing portion 3 is provided at the tip thereof. In this embodiment, the closing portion 3 and the cylindrical portion 4 are formed of stainless steel (SUS304 or SUS316).
A pipe formed of a titanium material, a Hastelloy material, a Monel metal material, an Inconel material, and a steel material (SS material, SC material, etc.) may be used. The diaphragm 2 which is a membrane plate formed at the tip of the closing portion 3 is welded to a support 2c at a substantially central portion of the vibrating body 2 so that the vibrating body 2 penetrates. By being welded to the portion 3, the vibrating body 2 is supported at substantially its center. A vibrating portion 2b disposed inside the cylindrical portion 4 of the vibrating body 2 has a lead titanate lead zirconate (PbTiO ₃ -Pb) for vibrating the vibrating body 2.
A vibration element 8 as a vibration means, which is a piezoelectric element containing ZrO ₃ ) as a main component, is attached to a side surface of the vibration section 2b.
The vibrating element 8 is electrically connected to an electric circuit provided inside the base 1 via a lead wire 11 passing through a through hole 2d formed in the support 2c of the vibrating body 2. Therefore, since the lead wire 11 is in contact with the edge of the through hole 2d,
The tension of the lead wire 11 is dispersed, and the tension of the lead wire 11 to the connecting portion between the vibrating element 8 and the lead wire 11 is reduced.

An acceleration sensing element 10, which is a vibration detecting means, is provided at a tip 9 provided at the tip of a sensing portion 2a projecting from the cylindrical portion 4 into the container 6. The two vibration directions are arranged in the same direction.
The signal from the acceleration sensing element 10 is transmitted through a lead 11 to an electric circuit provided on the base 1 through the inside of the sensing unit 2a.

In the base 1, the lead wire 11 is held by a rubber support substantially at the center of the weight 7 by crimping of a lead wire fixing bolt 13, and the printed board 15
Etc. are electrically connected. This printed circuit board 15
The vibrating body 2 is fixed to a vibration isolating rubber 14 fixed to the weight 7 so that the vibration of the vibrating body 2 is not transmitted to the printed circuit board 15. Reference numeral 12 denotes a terminal plate, which is provided with an input power supply terminal and an output terminal. This terminal board
The lead wire (not shown) connected to 12 is configured to be able to be led out from the electric wire grant 16.

FIG. 2 is a plan sectional view of the vibration type level detector shown in FIG. 1 as viewed from above. 1 and 2
As shown in FIG. 2, the vibrating body 2 is composed of a cylindrical sensing part 2a, a flat vibration part 2b, and a support part 2c having a flat cross section. 3 and 4 show enlarged views of the vibrating body 2. FIG. 3 and 4, the lead wire 11 is omitted. The vibrating body 2 is made of stainless steel (SUS304 or SUS31).
The pipe of 6) is integrally molded into a different shape. That is, the vibrating portion 2b is formed by press-forming to completely crush the pipe, which is a material, in the diameter direction, and the supporting portion 2c is formed by press-forming so that the cross section becomes flat. Also,
The sensing unit 2a is configured in a pipe shape so as not to be easily deformed or broken even when the object to be detected contacts. The acceleration sensing element 10 is fitted into a hole formed in the tip of the sensing portion 2a of the vibrating body 2 at the tip 9 of the sensing portion 2a.
The vibrating element 8 is fixed to the side surface. The vibrating body 2 is welded and fixed to the closing portion 3 at a substantially central welded portion 2e in the protruding direction as shown in FIGS.

The operation of this embodiment of the vibration type level detecting device according to the present invention configured as described above will be described. In this vibration type level detecting device, the vibrating body 2 vibrates with the welded portion 2e of the closed portion 3 and the support portion 2c as a node when excited by the vibration element 8. Since the weight 7 as a heavy object is provided inside the base 1, the vibration of the vibrating body 2 is stabilized. Therefore, even if the structure, material, and mass of the container 6 or the like to which the vibration type level detecting device of the present embodiment is mounted are different, and even if the vibration level detecting device is mounted on the container 6 or the like by a method different from the above-described embodiment, The vibrator 2 vibrates stably in substantially the same vibration mode. The vibration mode of the vibrating body 2 is detected by an acceleration sensing element 10 provided at the tip 9 of the vibrating body 2 and is converted into an electric signal.

FIG. 5 shows a block diagram of an electric circuit housed in the base 1. The vibrating body 2 includes a vibrating element 8
The vibrating element 8 receives a signal from the amplifying circuit 17 for forcibly exciting the oscillating device to be in a vibrating state. The vibration state of the vibrating body 2 is converted into an electric signal by the acceleration sensing element 10 provided at the distal end portion 9 and input to the amplifier circuit 17. The signal input to the amplifying circuit 17 is amplified,
(Positive feedback loop). Therefore, the vibrating body 2
Self-oscillates and vibrates according to the natural frequency of the vibrating body 2.

The vibration mode of the vibrating body 2 is detected by a detection circuit 18 to which an electric signal from the acceleration sensing element 10 is input, and a detection signal is output by the detection circuit 18.
This detection signal is supplied to the acceleration sensing element provided at the tip 9.
Since it is based on the output signal from 10, the vibration mode of the tip 9 is accurately shown. As described above, when the vibrating body 2 is vibrating at the natural frequency, if the object to be detected, such as a granular material or a liquid, comes into contact with the sensing unit 2a of the vibrating body 2, the vibration of the vibrating body 2 is attenuated or Stop. The state where the vibration of the vibrating body 2 is attenuated or stopped is determined by the tip 9 of the sensing unit 2a of the vibrating body 2.
Remarkably and surely. For this reason, the change of the vibration mode of the vibrating body 2 is detected with high accuracy by the acceleration sensing element 10 provided at the tip 9 of the sensing unit 2a. The vibration mode detected by the acceleration sensing element 10 is
It is converted into an electric signal and transmitted to an electric circuit provided inside the base 1. As another embodiment, a detection signal from the detection circuit 18 of the vibration type level detection device in the above-described embodiment is input to the comparison circuit and compared with the reference vibration mode, and only when the value exceeds a predetermined value. You may comprise so that the signal which operates a relay may be output.

[0017]

As described above, according to the vibration type level detecting device of the present invention, since the acceleration sensing element as the vibration detecting means is provided at the tip of the sensing part of the vibrating body, the vibrating body depends on the object to be detected. Regardless of whether the vibration is attenuated or forcedly stopped, it is possible to reliably and accurately detect the presence of the detection target at a predetermined level or higher in various containers and the like. In addition, since the sensing part, support part, and detection part of the vibrating body can be easily formed with high precision by press-molding the pipe into different shapes suitable for each function, a high-precision vibration level suitable for mass production A detection device can be obtained.

[Brief description of the drawings]

FIG. 1 is a side sectional view showing a vibration type level detecting device according to an embodiment of the present invention.

FIG. 2 is a plan cross-sectional view of the vibration type level detecting device of FIG.

FIG. 3 is a side sectional view showing the vicinity of a vibrating body in the vibration type level detecting device of FIG. 1;

FIG. 4 is a plan cross-sectional view near the vibrating body of FIG. 3;

FIG. 5 is a block diagram of the vibration type level detecting device of FIG. 1;

FIG. 6 is a side sectional view showing a conventional vibration type level detecting device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Base part 2 Vibration body 2a Sensing part 2b Vibration part 3 Closure part 6 Container 8 Vibration element 9 Tip part 10 Acceleration sensing element

Claims (3)

(57) [Claims] A base fixed to the outside of a container or the like that stores an object to be detected, a vibrating body whose substantially central portion is supported by a closed portion led out from the base to the inside of the container or the like. A vibrating body in which an inner portion disposed inside the closing portion is formed in a flat plate shape, and an outer portion protruding from the closing portion is formed in a substantially cylindrical shape; A vibrating level, comprising: vibrating means provided to vibrate the vibrating body; and vibration detecting means provided at a tip of an outer portion of the vibrating body to detect a vibration state of the vibrating body. Detection device. 2. The vibration type level detecting device according to claim 1, wherein said inner portion and said outer portion of said vibrator are formed by pressing a cylindrical pipe into one piece. 3. The vibrating level detecting device according to claim 2, wherein said vibration detecting means comprises an acceleration detecting element for detecting an acceleration of a tip of an outer portion of said vibrating body.