KR101963732B1 - Fluid Level Measuring Ultrasonic Transducer - Google Patents

Fluid Level Measuring Ultrasonic Transducer Download PDF

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Publication number
KR101963732B1
KR101963732B1 KR1020160032156A KR20160032156A KR101963732B1 KR 101963732 B1 KR101963732 B1 KR 101963732B1 KR 1020160032156 A KR1020160032156 A KR 1020160032156A KR 20160032156 A KR20160032156 A KR 20160032156A KR 101963732 B1 KR101963732 B1 KR 101963732B1
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KR
South Korea
Prior art keywords
housing
piezoelectric transducer
housing part
lower housing
liquid
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Application number
KR1020160032156A
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Korean (ko)
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KR20170108374A (en
Inventor
이덕규
김영민
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(주)동일기연
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Priority to KR1020160032156A priority Critical patent/KR101963732B1/en
Priority to PCT/KR2017/002851 priority patent/WO2017160102A1/en
Publication of KR20170108374A publication Critical patent/KR20170108374A/en
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Publication of KR101963732B1 publication Critical patent/KR101963732B1/en

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
    • G01F23/00—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
    • G01F23/00—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm
    • G01F23/04—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm by dip members, e.g. dip-sticks
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
    • G01F23/00—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm
    • G01F23/22—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm by measuring physical variables, other than linear dimensions, pressure or weight, dependent on the level to be measured, e.g. by difference of heat transfer of steam or water
    • G01F23/26—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm by measuring physical variables, other than linear dimensions, pressure or weight, dependent on the level to be measured, e.g. by difference of heat transfer of steam or water by measuring variations of capacity or inductance of capacitors or inductors arising from the presence of liquid or fluent solid material in the electric or electromagnetic fields

Abstract

The present invention relates to a transducer for generating ultrasonic waves for measuring the level of liquid in a tank and detecting a reflected wave reflected from the surface of the liquid. The transducer comprises a combination of an upper housing 110 and a lower housing 120, A housing part (100) for forming the housing part (100); A piezoelectric transducer (200) attached to an inner space of the housing part (100) and generating an ultrasonic wave according to an electrical signal and receiving a reflected wave returned from the liquid surface to generate an electric signal; And a terminal 300 connected to the piezoelectric transducer 200 at one side and to the outside of the housing 100 at the other side to transmit and receive an electrical signal between the external circuit and the piezoelectric transducer 200 The upper housing 110 and the lower housing 120 are sealed to each other to maintain watertightness and the gap between the housing part 100 and the terminal 300 is filled with the chemical resistant insulating filler 330, So that the liquid can not penetrate into the housing part 100.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a liquid level measuring ultrasonic transducer,

The present invention relates to an ultrasonic transducer for measuring the level of a liquid (for example, fuel, oil, organic matter, etc.), and is characterized in that the ultrasonic transducer is combined with a completely sealed structure so that liquid does not flow into the housing portion where the piezoelectric transducer is mounted do.

Ultrasonic transducers are used in liquid level measurement devices inside liquid tanks. Generally, liquid tanks are equipped with a sensing structure to measure the level of liquid stored therein. The liquid level sensing device includes an ultrasonic sensor and an electric control device, and an ultrasonic transducer used as an ultrasonic sensor is disposed in the form of being attached to the bottom of the tank or mounted inside the tank.

When the ultrasonic transducer is attached to the bottom of the tank, the ultrasonic wave transmittance is lowered due to the reflected wave generated at the outer wall of the tank bottom, and the reception sensitivity is lowered. Also, when the level of the liquid level in the tank is low, reflected waves from the outer wall of the tank and reflected waves from the liquid surface are superimposed on each other, resulting in poor measurement accuracy, which may limit the measurable level range. In order to solve such a problem, JP 2004-333256 proposes a method of changing the resonance frequency of the ultrasonic transducer to seven steps to find the highest transmittance frequency, and driving the ultrasonic transducer at the frequency. However, even if an optimum driving frequency with a high transmittance is used, the reflected wave caused by the outer wall of the tank is not completely removed.

In US 6,993,967, an ultrasonic transducer is mounted inside a fuel tank of a vehicle, in which all components including the piezoelectric transducer and the epoxy are exposed to the fuel. In this case, the fuel penetrates into the polymeric material and the adhesive agent, and the adhesion between the piezoelectric conversion element and the instrument can be deteriorated in the long term. If the adhesion between the piezoelectric conversion element and the instrument is decreased, the driving reverberation waveform increases, And ultrasound transmission and reception may become impossible.

Another example (US Pat. No. 7,861,587 B2) relates to a level sensor packaged with an electronic component (ASIC), in which a packaging technique is used to provide a seal from the liquid, but the housing (packaging) This is disadvantageous in terms of long-term durability, because if the housing is plastic or polymer, it can not prevent liquid penetration 100%. Especially, when the liquid is gasoline, it is reported that the penetration is very high. The penetration rate of gasoline fuel to polyphenylene sulfide (PPS), which is known to have the highest durability against gasoline, is CE10 (gasoline 90% + ethanol 10%) , And 0.1 to 0.3 (g-mm / m 2 -day), respectively.

Therefore, recently, a high long-term durability reliability is demanded for a vehicle component, and therefore measures against the infiltration of liquids are urgently needed.

It is an object of the present invention to provide an ultrasonic transducer mounted inside a liquid tank and having a sealing structure in which penetration of liquid is completely blocked.

Technical features of the present invention are as follows.

The present invention relates to a transducer for generating ultrasonic waves for measuring the level of liquid in a tank and detecting a reflected wave reflected from the surface of the liquid. The transducer comprises a combination of an upper housing 110 and a lower housing 120, A housing part (100) for forming the housing part (100); A piezoelectric transducer (200) attached to an inner space of the housing part (100) and generating an ultrasonic wave according to an electrical signal and receiving a reflected wave returned from the liquid surface to generate an electric signal; And a terminal 300 connected to the piezoelectric transducer 200 at one side and to the outside of the housing 100 at the other side to transmit and receive an electrical signal between the external circuit and the piezoelectric transducer 200 The upper housing 110 and the lower housing 120 are sealed to each other to maintain watertightness and the gap between the housing part 100 and the terminal 300 is filled with the chemical resistant insulating filler 330, So that the liquid can not penetrate into the housing part 100.

According to the configuration of the present invention, the following technical effect can be achieved.

First, a metal or a ceramic is used as the material of the housing part 100 of the ultrasonic transducer for measuring the liquid level, and a gap space between the housing part 100 and the terminal 300 is filled with an insulating filler 330 So that the ultrasonic transducer mounted inside the housing part 100 is protected from the penetration of the liquid, and the ultrasonic transducer mounted inside the housing part 100 is exposed to the liquid It is possible to secure high durability even in a structure used as a mold.

Second, by filling the damping material 400 in the housing part 100, it is possible to control the vibration of the piezoelectric transducer element 200 and reduce the reverberation time in receiving the reflected wave, thereby increasing the measurement accuracy.

Third, the thickness of the ultrasonic wave emitting surface of the housing part 100 to which the piezoelectric transducer 200 is attached can be optimized according to the driving frequency, thereby ensuring a high level of measurement accuracy.

1 is an assembled cross-sectional view of an ultrasonic transducer according to a specific embodiment of the present invention.
2 is a diagram illustrating an example of attachment of a lower housing 120 and a piezoelectric transducer 200 of an ultrasonic transducer according to a specific embodiment of the present invention.
3 is an exploded view and assembled view of a lower housing 120 of an ultrasonic transducer according to a specific embodiment of the present invention.
4 is a detailed assembly view of the lower housing 120 and terminal 300 joints of the ultrasonic transducer according to a specific embodiment of the present invention.
5 is an assembled sectional view of an ultrasonic transducer according to another embodiment of the present invention, showing that the lower housing 120 can be manufactured in various forms.
6 is a detailed assembly view of the lower housing 120 and the terminal 300 joint of the ultrasonic transducer according to another embodiment of the present invention.
7 is an assembled sectional view of an ultrasonic transducer according to another embodiment of the present invention in which the terminal 300 is mounted on the upper housing 110 and the piezoelectric transducer 200 is attached to the lower housing 120 / RTI >

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings.

The present invention relates to a transducer for generating ultrasonic waves for measuring the level of liquid in a tank and detecting reflected waves reflected from the surface of the liquid.

As shown in FIG. 1, the housing unit 100 includes an upper housing 110 and a lower housing 120 to form an inner space.

The piezoelectric transducer 200 is mounted in the inner space. In some cases, a driving circuit for operating the piezoelectric transducer 200 and a circuit for sending and receiving the measurement result to the outside may be incorporated.

The upper housing 110 and the lower housing 120 may be made of the same material and may be made of a metal material or a ceramic material. When the upper housing 110 and the lower housing 120 are made of a metal material, the upper housing 110 and the lower housing 120 may be brazed or soldered when they are made of a ceramic material so that the upper housing 110 and the lower housing 120 are sealed together along the rims which are in contact with each other by welding, brazing or soldering. Quot;) < / RTI > manner. In addition, the upper housing 110 and the lower housing 120 may be formed as a single body from the beginning, rather than being assembled by dividing into various bodies as shown in the sectional structure shown in FIG.

The upper housing 110 and the lower housing 120 are made of metal or ceramic and have excellent chemical resistance and are sealed by welding, brazing, or soldering, Can be prevented from flowing into the inside of the housing part (100).

The specific shapes of the upper housing 110 and the lower housing 120 constituting the housing part 100 may be various shapes such as a circular shape, an elliptical shape, a square in which edges are smoothly processed, and the like. 1, a flange may be formed on the rim where the upper housing 110 and the lower housing 120 are in contact with each other so that mutual surface contact can be established.

The thickness of the upper housing 110 and the lower housing 120 constituting the housing part 100 may be 0.03 to 3.0 mm, depending on the frequency.

The portion of the ultrasonic wave emitting surface 130 of the lower housing 120 to which the piezoelectric transducer 200 is attached is formed in a shape and a size corresponding to the piezoelectric transducer 200 as shown in FIGS. The depth of the ultrasonic wave radiating surface 130 is 0.5 to 5.0 mm, and the thickness of the lower housing 120 is 0.03 to 3 mm.
When the lower housing 120 is provided with a depressed step corresponding to the shape and size of the piezoelectric transducing element 200, the piezoelectric transducing element 200 is attached so as to be accommodated in the depressed portion, The structural strength of the housing 120 increases and displacement of the piezoelectric transducer 200 is reduced even if vibration is transmitted from the outside, so that the low frequency vibration noise can be minimized.

The piezoelectric transducer 200 is attached to the inner space of the housing 100 and generates ultrasonic waves in response to an electrical signal and receives reflected waves returned from the liquid surface to generate an electrical signal.

Such a piezoelectric transducer 200 can be selected among a variety of products that have been developed and commercialized at present. The size of the piezoelectric transducer 200 generally increases as the required measurement liquid level becomes larger, and the thickness becomes thicker. However, when a high level of measurement precision is required, it is advantageous to use a high frequency ultrasonic wave in order to increase the resolution. It is advantageous to have a thickness of 1 mm or less. In a specific embodiment of the present invention, 4 mm.

In order to generate ultrasonic waves, an external signal must be applied to the piezoelectric transducer. In order to sense the reflected wave reflected from the surface of the liquid, an electric signal generated from the piezoelectric transducer 200 must be transmitted to the outside. For this purpose, as shown in FIG. 2, a wire 320 for transmitting and receiving an electrical signal is drawn from the upper surface and the lower surface of the piezoelectric transducer 200 and connected to the upper portion of the terminal 300 by soldering or wire bonding.

That is, one side of the terminal 300 is connected to the piezoelectric transducer 200 through the electric signal line and the other side is protruded to the outside of the lower housing 120 to transmit and receive an electric signal between the external circuit and the piezoelectric transducer 200 And two terminals may be required as shown in FIG. 2, and a separate terminal for communication may be added.

In order for the terminals 300 to protrude to the outside through the lower housing 120, holes through which the terminals 300 pass through the lower housing 120 must be pierced. When the holes are perforated, There is a possibility that the liquid penetrates into the housing part 100 through the space between the hole of the housing part 120 and the terminal 300. [ Therefore, it is necessary to seal the gap space with the chemical-resistant insulating filler 330 so that the liquid can not penetrate into the housing part 100.

At this time, when the thickness of the lower housing 120 constituting the housing part 100 is thin, a sealing process is performed by inserting the insulating filler 330 having chemical resistance into the hole of the lower housing A terminal fitting tube 310 in the form of a flanged bushing having a flange at a hole of the lower housing 120 through which the terminal 300 passes can be first brazed or soldered soldering.

The chemical resistant insulating filler 330 inserted into the terminal fitting tube 310 is made of a glass tube in the form of a tube so that the terminal 300 can pass through the center as shown in FIG. 3 or 4, The glass tube is melted and fused while completely filling the gap space between the terminal 300 and the terminal fitting tube 310 in the heat treatment process.

A burring process may be carried out in the process of forming a hole in the lower housing 120 without separately joining the terminal fitting tube 310 to the terminal 300 Can be secured.

5, since the thickness of the lower housing 120 is thick enough to fit the terminal 300, it is possible to directly attach the chemical-resistant insulating filler to the hole of the lower housing 120 without installing the terminal- And the sealing member 330 is bonded by sealing.

In addition, in order to secure the inner space of the housing part 100, the upper housing 110 must be formed in a container shape.

The damping material 400 controls the vibration of the piezoelectric transducer 200 while filling the internal space of the housing part 100 composed of the upper housing 110 and the lower housing 120 to reduce the reverberation time It serves to increase accuracy.

The damping material 400 may be in the form of a soft silicone, a soft epoxy or a soft urethane and may be in the form of a foam. The damping material 400 may be in the form of a damping material 400 before the upper housing 110 and the lower housing 120 are joined Fill it.

6 shows a case where the lower housing 120 is electrically used as a (-) pole and a ground, and the piezoelectric transducer 200 is directly attached to the lower housing 120 made of metal by using a conductive adhesive The piezoelectric transducer 200 and the lower housing 120 are electrically connected to each other so that one of the two terminals 300 can be directly connected to the lower housing 120. In this case, only one insulator filler 330 having chemical resistance and one wire 320 for transmitting / receiving an electric signal are required, which may have many advantages in the manufacturing process.

7 shows the case where the terminal 300 and the ultrasonic wave emitting surface 130 are opposite to each other and the thickness of the upper housing 110 on which the terminal 300 is mounted is too thick to attach the terminal fitting tube 310 separately The terminals 300 can be mounted using the insulating filler 330 having chemical resistance.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is clearly understood that the same is by way of illustration and example only and is not to be taken by way of limitation, Addition or deletion of a technique, and limitation of a numerical value are included in the protection scope of the present invention.

100: housing part
110: upper housing
120: Lower housing
130: ultrasonic wave emitting surface
200: piezoelectric transducer
300: terminal
310: Terminal mounting tube
320: wire
330: Insulation filler
400: Damping material

Claims (9)

The present invention relates to a transducer for generating ultrasonic waves for measuring the level of liquid in a tank and detecting reflected waves reflected from the surface of the liquid,
A housing part 100 formed by combining the upper housing 110 and the lower housing 120 to form an inner space;
A piezoelectric transducer (200) attached to the inside of the lower housing (120) of the housing part (100) to generate an ultrasonic wave according to an electric signal and receive a reflected wave returned from the liquid surface to generate an electric signal;
The piezoelectric transducer 200 is mounted on the inside of the lower housing 120 of the housing part 100 and has one side connected to the piezoelectric transducer 200 and the other side projecting to the outside of the housing 100, 200 for transmitting and receiving an electrical signal; And
A damping material (400) for controlling the vibration of the piezoelectric transducer (200) while filling the internal space of the housing part (100) to increase the measurement accuracy by reducing the reverberation time upon receipt of reflected waves;
And,
Each of the upper housing 110 and the lower housing 120 is made of one unassembled body and the upper housing 110 and the lower housing 120 are sealed and bonded to maintain watertightness. is sealingly bonded by welding, brazing or soldering in the case of a ceramic material and sealingly joined by brazing or soldering in the case of a ceramic material,
A terminal fitting tube 310 in the form of a flanged bushing having a flange is brazed to the hole formed in the lower housing 120 of the housing part 100, Or a soldering process or a burring process is performed in the process of perforating a hole through which the terminal 300 passes,
The gap between the lower housing 120 of the housing part 100 and the terminal 300 is sealed with glass which is the chemical resistant insulating filler 330 so that the liquid can not penetrate into the housing part 100 ,
The portion of the ultrasonic wave emitting surface 130 of the lower housing 120 of the housing unit 100 to which the piezoelectric transducer 200 is attached is recessed in a shape and size corresponding to the piezoelectric transducer 200, The structural strength of the lower housing 120 is increased and the displacement of the piezoelectric transducer 200 due to the external vibration is reduced,
The damping material 400 is a soft silicone, a soft epoxy or a soft urethane,
The thickness of the ultrasonic radiation surface 130 of the housing part 100 to which the piezoelectric transducer 200 is attached is 0.03 to 3 mm,
Wherein the piezoelectric transducer (200) has a diameter of 1 to 20 mm and a thickness of 0.03 to 4 mm. The method of claim 1,
A driving circuit for operating the piezoelectric transducer (200) so that ultrasonic waves are transmitted and received inside the housing part (100), and a circuit for externally sending and receiving measurement results are incorporated Ultrasonic transducer.
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KR1020160032156A 2016-03-17 2016-03-17 Fluid Level Measuring Ultrasonic Transducer KR101963732B1 (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
KR1020160032156A KR101963732B1 (en) 2016-03-17 2016-03-17 Fluid Level Measuring Ultrasonic Transducer
PCT/KR2017/002851 WO2017160102A1 (en) 2016-03-17 2017-03-16 Fluid level measuring ultrasonic transducer

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
KR1020160032156A KR101963732B1 (en) 2016-03-17 2016-03-17 Fluid Level Measuring Ultrasonic Transducer

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KR20170108374A KR20170108374A (en) 2017-09-27
KR101963732B1 true KR101963732B1 (en) 2019-03-29

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Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2001159551A (en) * 1999-12-03 2001-06-12 Matsushita Electric Ind Co Ltd Support structure of ultrasonic vibrator and ultrasonic flow rate measuring device using it
JP2004294181A (en) * 2003-03-26 2004-10-21 Matsushita Electric Ind Co Ltd Ultrasonic oscillator and fluid flow measuring device using it

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE59510158D1 (en) * 1995-09-28 2002-05-16 Endress Hauser Gmbh Co ultrasound transducer
JP3596364B2 (en) * 1999-08-05 2004-12-02 松下電器産業株式会社 Ultrasonic transducer and ultrasonic flow measurement device
US7421895B1 (en) * 2005-04-21 2008-09-09 Caldwell Joseph W Fluid level measuring system
JP2008157850A (en) * 2006-12-26 2008-07-10 Matsushita Electric Ind Co Ltd Ultrasonic vibrator and manufacturing method thereof, and ultrasonic flow velocity flowmeter
DE102009046146A1 (en) * 2009-10-29 2011-05-12 Robert Bosch Gmbh Ultrasonic transducer for use in a fluid medium
DE102009046148A1 (en) * 2009-10-29 2011-05-05 Robert Bosch Gmbh Ultrasonic transducer for use in a fluid medium

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2001159551A (en) * 1999-12-03 2001-06-12 Matsushita Electric Ind Co Ltd Support structure of ultrasonic vibrator and ultrasonic flow rate measuring device using it
JP2004294181A (en) * 2003-03-26 2004-10-21 Matsushita Electric Ind Co Ltd Ultrasonic oscillator and fluid flow measuring device using it

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KR20170108374A (en) 2017-09-27

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