JPH06160155A - Ultrasonic sensor - Google Patents

Abstract

PURPOSE:To solve the accumulation of bubbles at the lower face section of a ultrasonic sensor, suppress the attenuation of ultrasonic waves, improve the propagation state of ultrasonic waves, and allow accurate measurement. CONSTITUTION:A ultrasonic sensor 1 is constituted of a sensor main body section 3 and a sensor cover 4 covering the sensor main body section 3, the bottom face section 11 of the sensor cover 4 is formed into a slant face, water (or an antifreezing solution) for ultrasonic propagation is sealed between the sensor cover 4 and the sensor main body section 3, and an organism repellent paint is coated on the surface of the sensor cover 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic sensor,
In particular, the present invention relates to an ultrasonic sensor suitable for preventing bubbles from staying on the lower surface of the sensor.

[0002]

2. Description of the Related Art Conventionally, for example, when measuring the distance to a precipitate containing organic components that has settled at the bottom of a settling tank, ultrasonic waves are emitted to the precipitate and reflected by the ultrasonic wave. Based on the above, an ultrasonic interface level meter that measures the distance to the precipitate is used. FIG. 6 shows an ultrasonic sensor 50 to be used by connecting it to an ultrasonic interface level meter, which usually has a disk-shaped piezoelectric ceramic 51 built-in, and the sensor surface is covered and protected with resin or metal. It has a structure in which the lower surface portion 52 from which ultrasonic waves are radiated is formed into a flat surface. At the time of measurement, as shown in FIG. 7, the lower surface portion 52 of the ultrasonic sensor 50 is placed horizontally in the liquid of the settling tank 54 in which the precipitate 53 is stored, and the measurement is performed.

[0003]

However, the above-mentioned prior art has the following problems. Air bubbles are constantly generated in the liquid in the settling tank 54, and when the measurement target is a precipitate containing organic matter such as activated sludge, bacteria in the liquid in the settling tank 54 are A large amount of gas may be generated when the organic components are decomposed, and the generated gas amount may reach 2 liters per 1 square meter in 1 hour. However, since the lower surface portion 52 of the ultrasonic sensor 50 is formed to be a flat surface and the lower surface portion 52 is horizontally arranged in the liquid, air bubbles K generated from the liquid in the settling tank 54 and bacteria can remove organic substances. As a result of the bubbles K generated during decomposition accumulating in the lower surface portion 52 of the ultrasonic sensor 50 to form a bubble pool, there is a problem that the ultrasonic waves are greatly attenuated. In the settling tank 54 containing organic matter, snails, worms, and algae that feed on organic matter easily propagate, so that the settling tank 5
Each part in 4 will be covered, but these creatures
Since it easily adheres to the surface of the ultrasonic sensor 50 arranged in the settling tank 54, there is a problem that the propagation state of the ultrasonic wave emitted from the ultrasonic sensor 50 is deteriorated and the measurement is hindered.

[0004]

SUMMARY OF THE INVENTION The present invention is to solve the above-mentioned problems.
An object of the present invention is to provide an ultrasonic sensor capable of performing accurate measurement by suppressing the accumulation of bubbles in the lower surface of the ultrasonic sensor, suppressing the attenuation of ultrasonic waves, and improving the propagation state of ultrasonic waves.

[0005]

In order to achieve the above object, the present invention provides an ultrasonic wave for radiating ultrasonic waves to a precipitate deposited on the bottom of a liquid in a settling tank and detecting ultrasonic waves reflected from the precipitate. The sensor includes a sensor main body that radiates ultrasonic waves and a sensor cover that is disposed outside the sensor main body. The bottom surface of the sensor cover is formed as an inclined surface, and the sensor cover is provided. A liquid for ultrasonic wave propagation is enclosed between the sensor main body and the sensor main body, and a bio-repellent paint is applied to the surface of the sensor cover.

[0006]

According to the ultrasonic sensor of the present invention, the sensor cover is disposed outside the sensor body, and the bottom surface of the sensor cover is formed into an inclined surface so that the space between the sensor cover and the sensor body is increased. Since a liquid for ultrasonic wave propagation is sealed in and the surface of the sensor cover is coated with bio-repellent paint, air bubbles generated in the liquid in the settling tank or from the precipitate are generated from the inclined bottom surface of the sensor cover. It is possible to allow the air to escape along the outer wall portion, and thereby to prevent the problem that the ultrasonic waves are greatly attenuated due to the accumulation of bubbles on the lower surface of the sensor as in the conventional case. Also, because the structure of the sensor cover is coated with a bio-repellent paint, snails, insects, algae, etc. that have propagated with organic matter as food in the sedimentation tank adhere to the surface of the sensor as in the past. It is possible to surely prevent a problem or the like that deteriorates the propagation state of sound waves and hinders measurement. As a result, the distance to the sediment can be accurately measured in a stable state for a long time even in a sedimentation tank in which bubbles are often generated.

[0007]

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

The structure of the ultrasonic sensor of this embodiment will be described with reference to FIGS. 1 to 4. The ultrasonic sensor 1 is a sensor connected to an ultrasonic interface level meter (see FIG. 5) via a signal line 2. The main body portion 3 and the sensor cover 4 mounted on the outer peripheral portion of the sensor main body portion 3 are roughly configured, and a biorepellent paint (not shown) is applied to the surface of the sensor cover. When measuring the distance to the precipitate 6 in the settling tank 5, the ultrasonic sensor 1 is arranged in the liquid 7 in a dipped state. The sensor body 3 is composed of a large-diameter first cylindrical portion 9 that houses the piezoelectric ceramics 8 and the like, and a small-diameter second cylindrical portion 10 that houses the signal line 2 and the like connected to the ultrasonic interface level meter. There is. In this case, as the bio-repellent paint, there are various ones such as a composition containing an organic copper complex as an active ingredient.

The sensor cover 4 is formed in a substantially cylindrical member, and the bottom surface portion 11 of the cylindrical member is processed into an inclined state having a predetermined angle with respect to the upper surface portion of the cylindrical member. Yes, the first cover portion 12 that covers the first cylindrical portion 9 of the sensor body portion 3 and the second cylindrical portion 1 of the sensor body portion 3
And a second cover portion 13 that covers 0.
Inside the first cover portion 12 of the sensor cover 4, the first cylindrical portion 9 of the sensor main body portion 3 is housed, and water (or antifreeze liquid) W is pre-injected into the space below the first cylindrical portion 9. The lower end portion of the second cylindrical portion 10 of the sensor body 3 is housed inside the second cover portion 13 of the sensor cover 4. An O-ring 13 is inserted between the first cover portion 12 and the second cover portion 13 of the sensor cover 4 in order to improve the sealing property.

Next, the structure of the ultrasonic interface level meter of the present embodiment will be described with reference to FIG. 5. The ultrasonic interface level meter has a transmission pulse generator 15 for generating ultrasonic transmission pulses to the ultrasonic sensor 1. An amplification unit 16 for amplifying the detection signal of the ultrasonic sensor 1, a waveform shaping unit 17 for waveform shaping the amplified signal, a detection unit 18 for detecting the waveform shaping signal, and a sediment 6 in the sedimentation tank 5. A time measurement unit 19 that measures the time from the emission of ultrasonic waves to the reflection and return of the ultrasonic waves, a calculation unit 20 that measures the distance to the precipitate 6 in the settling tank 5 based on the measurement time, and a measurement result. The display unit 21 for displaying, the output unit 22 for outputting the measurement result, and the operation unit 23.

Next, the operation of this embodiment constructed as described above will be described with reference to FIG.

When the distance to the precipitate 6 in the settling tank 5 is measured by the ultrasonic sensor 1, as shown in FIG. 4, the inside of the sensor cover 4 of the ultrasonic sensor 1 connected to the ultrasonic interface level meter. Water (or antifreeze liquid) W is injected into the liquid, the ultrasonic sensor 1 is placed in a state of being immersed in the liquid in the settling tank 5, and ultrasonic transmission pulses are supplied from the ultrasonic interface level meter to the ultrasonic sensor 1. By doing so, ultrasonic waves are emitted downward from the bottom surface portion 11 of the ultrasonic sensor 1 in the settling tank 5, and measurement is started.

At the time of the measurement, the liquid 7 in the settling tank 5
A large number of bubbles K are generated from the precipitates 6 and rise in the liquid. The ultrasonic sensor 1 is equipped with a sensor cover 4 coated with a bio-repellent paint, and the bottom surface of the sensor cover 4 is attached. Since 11 is formed in an inclined state, a large number of bubbles K reaching the bottom surface portion 11 of the ultrasonic sensor 1 are
Go up further along the slope of (see arrow Y1),
Finally, it reaches the outside of the sensor cover 4 of the ultrasonic sensor 1 and disappears on the liquid surface. That is, it is possible to prevent a phenomenon in which air bubbles are accumulated below the ultrasonic sensor 1.

On the other hand, the ultrasonic wave radiated from the bottom surface portion 11 of the ultrasonic sensor 1 propagates in the water (or antifreeze liquid) W in the sensor cover 4 and is attenuated because there is no bubble accumulation below the sensor cover 4. After reaching the precipitate 6 in the settling tank 5 (see arrow Y2), the ultrasonic waves reflected by the precipitate 6 return to the ultrasonic sensor 1. This allows
The ultrasonic interface level meter can accurately measure the distance to the precipitate 6. Also, at the time of the measurement,
Since the surface of the sensor cover 4 of the ultrasonic sensor 1 is coated with bio-repellent paint, snails, insects, algae, etc. that have propagated in the settling tank 5 with organic matter as food adhere to the sensor cover 4. The phenomenon can be reliably prevented.

As described above, according to this embodiment, the sensor cover 4 coated with the bio-repellent paint is attached to the outer peripheral portion of the ultrasonic sensor 1, and the bottom surface portion 11 of the sensor cover 4 is formed into the inclined surface. Due to the formed structure, there is a problem that air bubbles are accumulated on the lower surface of the sensor and ultrasonic waves are greatly attenuated as in the past, and snails, insects, algae, etc. propagated in the settling tank 5 with organic matter as food. It is possible to reliably prevent problems such as adhered to the surface of the sensor and deteriorating the propagation state of ultrasonic waves and hindering measurement. As a result, the distance to the precipitate 6 can be accurately measured in a stable state for a long time even in the settling tank 5 where many bubbles are generated.

[0016]

As described above, according to the ultrasonic sensor of the present invention, the sensor cover is arranged outside the sensor main body, and the bottom surface of the sensor cover is formed into an inclined surface. Since it has a structure in which a liquid for ultrasonic wave propagation is enclosed between the sensor main body and the sensor main body, air bubbles generated from the liquid in the settling tank or from the precipitate are guided along the outer wall of the sensor cover from the inclined bottom surface of the sensor cover. As a result, it is possible to prevent the problem that air bubbles are accumulated on the lower surface of the sensor and the ultrasonic waves are greatly attenuated as in the past, and in addition, a biorepellent paint is applied to the surface of the sensor cover. Due to this structure, snails, worms, algae, etc. that propagated in the settling tank with organic matter as food adhered to the sensor surface and deteriorated the ultrasonic wave propagation state, which hindered measurement. It is possible to reliably prevent problems, etc. Therefore, even in a sedimentation tank where a large amount of air bubbles are generated, the distance to the sediment can be accurately measured in a stable state for a long time, which is a remarkable effect. be able to.

[Brief description of drawings]

FIG. 1 is a front view of a sensor cover according to an embodiment of the present invention.

FIG. 2 shows the sensor cover of the present embodiment, which is taken along line AA of FIG.
It is arrow sectional drawing which follows the line.

3 is a plan view of the sensor cover according to the present embodiment as viewed in the direction of arrow B in FIG. 1. FIG.

FIG. 4 is a schematic diagram showing a measurement state by an ultrasonic sensor in the precipitation tank of this embodiment.

FIG. 5 is a block diagram of an ultrasonic interface level meter of the present embodiment.

FIG. 6 is a schematic diagram of a conventional ultrasonic sensor.

FIG. 7 is a schematic view showing a measurement state by an ultrasonic sensor in a settling tank of a conventional example.

[Explanation of symbols]

 1 Ultrasonic Sensor 3 Sensor Body 4 Sensor Cover 5 Sedimentation Tank 6 Sediment 7 Liquid 8 Piezoelectric Ceramics 11 Bottom Surface K Bubble W Water or Antifreeze

Claims (1)

[Claims] 1. An ultrasonic sensor for radiating ultrasonic waves to a sediment deposited on the bottom of a liquid in a sedimentation tank and detecting ultrasonic waves reflected from the sediment, a sensor main body emitting ultrasonic waves, and the sensor. A sensor cover arranged outside the main body, wherein the bottom surface of the sensor cover is formed into an inclined surface, and a liquid for ultrasonic wave propagation is provided between the sensor cover and the sensor main body. An ultrasonic sensor characterized in that a biological repellent paint is applied to the surface of the sensor cover.