WO2019167660A1 - Dispositif de détection de position de niveau de liquide - Google Patents

Dispositif de détection de position de niveau de liquide Download PDF

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Publication number
WO2019167660A1
WO2019167660A1 PCT/JP2019/005488 JP2019005488W WO2019167660A1 WO 2019167660 A1 WO2019167660 A1 WO 2019167660A1 JP 2019005488 W JP2019005488 W JP 2019005488W WO 2019167660 A1 WO2019167660 A1 WO 2019167660A1
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WIPO (PCT)
Prior art keywords
wave
transmission
surface portion
main surface
reception unit
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PCT/JP2019/005488
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English (en)
Japanese (ja)
Inventor
えみい 粉川
雅博 渡辺
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日本精機株式会社
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Application filed by 日本精機株式会社 filed Critical 日本精機株式会社
Priority to JP2020503385A priority Critical patent/JP7076072B2/ja
Publication of WO2019167660A1 publication Critical patent/WO2019167660A1/fr

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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
    • 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
    • G01F23/28—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 the variations of parameters of electromagnetic or acoustic waves applied directly to the liquid or fluent solid material
    • G01F23/296—Acoustic waves

Definitions

  • the present invention relates to a liquid level position detection device.
  • the speed of sound of a surface wave propagating through a portion of a propagating body in a liquid is slower than the speed of sound of a surface wave propagating through a portion exposed from the liquid.
  • the thing which detects the liquid level position of a liquid using this is disclosed.
  • the surface wave propagating through the propagating body is attenuated and the S / N ratio (Signal-Noise ratio) is deteriorated.
  • the detection accuracy may deteriorate.
  • the present invention has been made in view of the above circumstances, and an object of the present invention is to provide a liquid surface position detection device with high liquid surface position detection accuracy.
  • a liquid surface position detection device is A propagating body in which a ratio of a portion immersed in the liquid changes according to a liquid surface position; A first transmission / reception unit for generating a first surface wave in the propagation body and receiving a second surface wave; A second transmission / reception unit for generating the second surface wave in the propagating body and receiving the first surface wave; The liquid level position is detected based on at least one of the propagation time of the first surface wave received by the second wave transmitting / receiving unit and the propagation time of the second surface wave received by the first wave transmitting / receiving unit.
  • the propagator is A first main surface portion and a second main surface portion, which are in reverse relation to each other; And connecting the first main surface portion and the second main surface portion, and a bottom surface portion having a curved shape in a side view,
  • the first transmitting / receiving unit generates the first surface wave propagating through the first main surface unit
  • the second transmission / reception unit receives the first surface wave that has propagated through the first main surface portion and the bottom surface portion and the second main surface portion
  • the second wave transmitting / receiving unit generates the second surface wave propagating through the second main surface part
  • the first wave transmitting / receiving unit receives the second surface wave that has propagated through the second main surface portion and the bottom surface portion and the first main surface portion.
  • FIG. 1 It is a schematic block diagram of the liquid level position detection apparatus which concerns on 1st Embodiment of this invention.
  • (A) is a front view of the propagating body and vibrator according to the first embodiment, and (b) is a side view of the propagating body and vibrator according to the first embodiment. It is a schematic diagram for demonstrating a 1st surface wave and a 2nd surface wave. It is a flowchart which shows an example of a liquid level position detection process.
  • (A) is a front view of the propagating body and vibrator according to the second embodiment,
  • (b) is a side view of the propagating body and vibrator according to the second embodiment, and (c) It is a top view at the vibrator side of the propagating body according to the second embodiment.
  • FIG. 1 It is a schematic diagram for demonstrating a 3rd surface wave and a 4th surface wave.
  • A is a schematic diagram of the waveform for mainly explaining an internal propagation wave
  • (b) is a schematic diagram of the waveform by the propagation body which concerns on 2nd Embodiment. It is a flowchart which shows an example of a liquid level position detection process.
  • the liquid surface position detection device 100 is a device that detects the position of the liquid surface 91 of the liquid 90 put in the container 80. As the amount of the liquid 90 increases or decreases, the liquid level 91 also moves up and down.
  • the liquid level position detection apparatus 100 includes a propagation body 10, a vibrator 20, a transmission / reception circuit 30, and a control unit 40.
  • the propagating body 10 propagates a surface wave and is made of a synthetic resin such as PPS (polyphenylene sulfide).
  • the propagating body 10 has a strip shape that is long in the vertical direction.
  • the outer surface of the propagating body 10 includes an upper surface facing the vibrator 20, a bottom surface opposite to the upper surface, two main surfaces that connect the upper surface and the bottom surface, and have a reverse relationship with each other, and an upper surface and a bottom surface that are connected to each other. It is mainly composed of six sides, which are the two side surfaces that are in the relationship.
  • the propagating body 10 includes a main surface portion 11 (an example of a first main surface portion) including one of two main surfaces, and a main surface portion 12 (second main surface) including the other.
  • An example of the surface portion a side surface portion 13 including one of the two side surfaces, a side surface portion 14 including the other, a contact portion 15 including the upper surface and contacting the vibrator 20, and a bottom surface portion 16 including the bottom surface.
  • the surface wave propagates through the propagating body 10, but reaches the same depth as the wavelength of the surface wave from the surface of the propagating body 10 during propagation.
  • the main surface portion 11 and the main surface portion 12 are portions including not only the main surface of the propagation body 10 but also the depth. The same applies to the contact portion 15 and the bottom surface portion 16.
  • the main surface portion 11 hangs from one end of the contact portion 15 in a side view.
  • the main surface portion 12 hangs from the other end of the contact portion 15.
  • the bottom surface portion 16 connects the main surface portion 11 and the main surface portion 12 on the side opposite to the contact portion 15 and has a U-shaped smooth curved surface that protrudes downward.
  • the bottom surface portion 16 formed in this way reduces loss due to leakage when a first surface wave W1 and a second surface wave W2 described later propagate to the bottom surface portion 16.
  • the propagating body 10 is fixed by being sandwiched between fixing members 81 and 82 provided on the container 80 by the side surface portion 13 and the side surface portion 14.
  • the fixing method is arbitrary.
  • the propagating body 10 is arranged such that the lower end of the bottom surface portion 16 is separated from the bottom surface of the container 80 by a length d.
  • the length along the vertical direction from the upper end of the contact portion 15 to the liquid surface 91 in the propagation body 10 (the length of the first portion 10a where the propagation body 10 is not immersed in the liquid 90) L1 and the bottom surface
  • the length along the vertical direction from the lower end of the portion 16 to the liquid level 91 (the length of the second portion 10b where the propagation body 10 is immersed in the liquid 90) L2 varies depending on the increase or decrease of the liquid 90. .
  • the vibrator 20 is, for example, a transverse wave transducer and includes a piezoelectric element mounted on a circuit board. The vibrator 20 is pressed against the contact portion 15 of the propagating body 10 to generate surface waves on the main surface portion 11 and the main surface portion 12 of the propagating body 10.
  • first surface wave W1 the surface wave generated by the vibrator 20 on the main surface portion 11
  • second surface wave W2 the surface wave generated on the main surface portion 12
  • first surface wave W1 and the second surface wave W2 may be simply referred to as surface waves without being distinguished.
  • the vibrator 20 generates the first surface wave W1 in the propagating body 10 and generates the first surface wave receiving and receiving unit 21 that receives the second surface wave W2, and the propagating body 10 generates the second surface wave W2 and And a second transmission / reception unit 22 that receives the surface wave W1.
  • the first transmission / reception unit 21 vibrates by an electrical signal supplied from the transmission / reception circuit 30.
  • the vibration of the first transmitting / receiving unit 21 is transmitted to the propagation body 10, and the first surface wave W ⁇ b> 1 is generated at the upper end of the main surface part 11.
  • the generated first surface wave W ⁇ b> 1 propagates toward the lower end of the main surface portion 11, propagates along the bottom surface portion 16 having a smooth curved surface as described above, and then Propagate towards the top.
  • the first surface wave W1 that has reached the upper end of the main surface portion 12 causes the second wave transmitting / receiving portion 22 to vibrate.
  • the second transmission / reception unit 22 converts this vibration into an electric signal and supplies it to the transmission / reception circuit 30.
  • the second transmission / reception unit 22 vibrates by the electric signal supplied from the transmission / reception circuit 30.
  • the vibration of the second transmission / reception unit 22 is transmitted to the propagation body 10, and the second surface wave W ⁇ b> 2 is generated at the upper end of the main surface portion 12.
  • the generated second surface wave W2 propagates toward the lower end of the main surface portion 12, propagates along the bottom surface portion 16 having a smooth curved surface as described above, and then Propagate towards the top.
  • the second surface wave W2 that has reached the upper end of the main surface part 11 vibrates the first wave transmitting / receiving part 21.
  • the first transmission / reception unit 21 converts this vibration into an electric signal and supplies it to the transmission / reception circuit 30.
  • the generation of the first surface wave W1 in the propagation body 10 by the first transmitting / receiving unit 21 is also expressed as transmitting the first surface wave W1.
  • the generation of the second surface wave W2 in the propagation body 10 by the second transmitting / receiving unit 22 is also expressed as transmitting the second surface wave W2.
  • the first surface wave W1 and the second surface wave W2 are pulses (ultrasonic pulses) of ultrasonic waves (for example, a sound wave of 20 KHz or higher).
  • the first surface wave W1 and the second surface wave W2 are Rayleigh waves.
  • the vibrator 20 may include an ultrasonic contact medium that is interposed between the piezoelectric element and the propagating body 10 and that efficiently transmits vibration.
  • the transmission / reception circuit 30 is connected to the vibrator 20.
  • the transmission / reception circuit 30 supplies an electric signal for generating an ultrasonic pulse as a surface wave to the vibrator 20 to vibrate the vibrator 20.
  • the transmission / reception circuit 30 receives an electrical signal supplied from the transducer 20 as an ultrasonic reception circuit, and amplifies and converts the received electrical signal.
  • the transmission / reception circuit 30 supplies an electric signal for transmission of the first surface wave W1 to the first transmission / reception unit 21 to vibrate the first transmission / reception unit 21. Further, it receives an electrical signal supplied from the second transmitting / receiving unit 22 that has received the first surface wave W1, and amplifies and converts the received electrical signal. In addition, the transmission / reception circuit 30 supplies an electric signal for transmission of the second surface wave W ⁇ b> 2 to the second transmission / reception unit 22 to vibrate the second transmission / reception unit 22. Further, it receives an electrical signal supplied from the first transmitting / receiving unit 21 that has received the second surface wave W2, and amplifies and converts the received electrical signal.
  • the control unit 40 includes a microcomputer including a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), a timer, a D / A (digital / analog) converter, an A / D ( An analog / digital converter is included.
  • the control unit 40 is connected to the transmission / reception circuit 30.
  • the control unit 40 controls the transmission / reception circuit 30 to supply an electrical signal from the transmission / reception circuit 30 to each of the first transmission / reception unit 21 and the second transmission / reception unit 22 of the vibrator 20.
  • the first surface wave W1 is generated on the main surface portion 11 and the second surface wave W2 is generated on the main surface portion 12.
  • control unit 40 receives electrical signals from each of the first transmission / reception unit 21 and the second transmission / reception unit 22 of the vibrator 20 that are amplified and converted by the transmission / reception circuit 30, and based on the received electrical signals.
  • the liquid level position is detected as will be described later.
  • control unit 40 can exchange data with an external device 60 outside the liquid level position detection device 100. The configuration of the liquid surface position detection device 100 has been described above.
  • the operation of the liquid level position detection apparatus 100 will be described focusing on the liquid level position detection process (see FIG. 4) executed by the control unit 40.
  • the CPU of the control unit 40 executes the liquid surface position detection process using the RAM as a main memory, according to a program stored in the ROM, and using various data stored in the ROM.
  • the control unit 40 starts the liquid surface position detection process based on a command from the external device 60.
  • the generated first surface wave W ⁇ b> 1 propagates toward the lower end of the main surface portion 11, propagates along the bottom surface portion 16 having a smooth curved surface, and then toward the upper end of the main surface portion 12.
  • the first surface wave W1 that has reached the upper end of the main surface portion 12 causes the second wave transmitting / receiving portion 22 to vibrate.
  • the second transmission / reception unit 22 converts this vibration into an electric signal and supplies it to the transmission / reception circuit 30.
  • the transmission / reception circuit 30 amplifies and converts the supplied electric signal and supplies it to the control unit 40.
  • this amplified and converted electrical signal (that is, the first surface wave W1 that reaches the second transmitting / receiving unit 22 through propagation to the bottom surface part 16 shows vibrations generated by the second transmitting / receiving unit 22).
  • the electric signal is referred to as a first propagation wave signal.
  • the first surface wave W1 transmitted from the first wave transmitting / receiving unit 21 reaches the second wave transmitting / receiving unit 22 while the first portion 10a in contact with the gas and the second portion in contact with the liquid 90. It propagates across the boundary with 10b twice.
  • the control unit 40 sets a timer to an initial value of 0 in order to measure a period from when the process of step S1 is performed until the first propagation wave signal is received (step S2).
  • the period is a period from the timing at which the first transmitting / receiving unit 21 generates the first surface wave W1 to the timing at which the second transmitting / receiving unit 22 receives the first surface wave W1, and in short, the first transmitting / receiving wave. It is the propagation time of the first surface wave W1 from the unit 21 to the second transmission / reception unit 22 (hereinafter referred to as the first propagation time).
  • the control unit 40 determines whether or not the first propagation wave signal is received from the transmission / reception circuit 30 (step S3). This determination can be performed by an appropriate method. For example, the control unit 40 acquires the electric signal supplied from the second transmission / reception unit 22 and amplified and converted by the transmission / reception circuit 30. A value based on the voltage (for example, the voltage value, the average value of the square of the voltage value in a predetermined period, the change of the voltage value or the average value, the amplitude of the electrical signal, etc.) is equal to or greater than a threshold value stored in the ROM in advance. It is determined whether or not.
  • the control unit 40 acquires the electric signal supplied from the second transmission / reception unit 22 and amplified and converted by the transmission / reception circuit 30.
  • a value based on the voltage for example, the voltage value, the average value of the square of the voltage value in a predetermined period, the change of the voltage value or the average value, the amplitude of the electrical signal, etc.
  • the first propagation wave signal may be measured in advance by an experiment, and the threshold value may be determined based on the measurement result.
  • step S3 When the first propagation wave signal has not been received yet (step S3; No), the control unit 40 updates the timer value of the timer by +1 (step S4), and executes the process of step S3 again. As a result, the control unit 40 keeps timing until the first propagation wave signal is received.
  • the control unit 40 stores the current timer value as the first propagation time, for example, in the RAM (step S5).
  • control unit 40 vibrates the second transmission / reception unit 22 via the transmission / reception circuit 30 to generate the second surface wave W2 at the upper end of the main surface unit 12 (step S6).
  • the generated second surface wave W ⁇ b> 2 propagates toward the lower end of the main surface portion 12, propagates along the bottom surface portion 16 having a smooth curved surface, and then toward the upper end of the main surface portion 11. Propagate.
  • the second surface wave W2 that has reached the upper end of the main surface part 11 vibrates the first wave transmitting / receiving part 21.
  • the first transmission / reception unit 21 converts this vibration into an electric signal and supplies it to the transmission / reception circuit 30.
  • the transmission / reception circuit 30 amplifies and converts the supplied electric signal and supplies it to the control unit 40.
  • this amplified and converted electrical signal (that is, the second surface wave W2 that reaches the first transmission / reception unit 21 through propagation to the bottom surface part 16 shows vibration generated in the first transmission / reception unit 21).
  • Electrical signal is referred to as a second propagation wave signal.
  • the second surface wave W2 transmitted from the second transmitting / receiving unit 22 reaches the first transmitting / receiving unit 21 while the first portion 10a contacting the gas and the second portion contacting the liquid 90. It propagates across the boundary with 10b twice.
  • the control unit 40 sets a timer to an initial value of 0 in order to measure a period from when the process of step S6 is performed until the second propagation wave signal is received (step S7).
  • the period is a period from the timing at which the second transmitting / receiving unit 22 generates the second surface wave W2 to the timing at which the first transmitting / receiving unit 21 receives the second surface wave W2, in short, the second transmitting / receiving wave.
  • This is the propagation time of the second surface wave W2 from the unit 22 to the first transmission / reception unit 21 (hereinafter referred to as the second propagation time).
  • the first propagation time and the second propagation time may be simply referred to as propagation time without being distinguished.
  • control unit 40 determines whether or not the second propagation wave signal is received from the transmission / reception circuit 30 (step S8). This determination is performed in the same manner as in step S3, and when the second propagation wave signal has not been received yet (step S8; No), the control unit 40 updates the timer value of the timer to +1 or the like ( Step S9), the process of step S8 is executed again. Thereby, the control unit 40 performs time measurement until the second propagation wave signal is received.
  • control unit 40 stores the current timer value as the second propagation time, for example, in the RAM (step S10).
  • control unit 40 specifies the position of the liquid surface 91 (liquid surface position) based on the first propagation time stored in step S5 and the second propagation time stored in step S10 (step S11). .
  • the relationship between the first propagation time, the second propagation time, and the position of the liquid level 91 is specified in advance by experiments or the like, and the specified relationship is stored in the ROM as a table or an arithmetic expression.
  • the control unit 40 specifies the liquid level position based on the table or arithmetic expression stored in the ROM, and the first propagation time and the second propagation time.
  • control part 40 uses the table for calculating a liquid level position based on 1st propagation time, or a computing equation, and says the liquid level position (henceforth a 1st liquid level position) based on 1st propagation time. ) And a liquid surface position based on the second propagation time (hereinafter referred to as the second liquid surface position) using a table or an arithmetic expression for identifying the liquid surface position based on the second propagation time. You may specify. That is, the control unit 40 may specify each of the first liquid level position and the second liquid level position. The average of the first liquid level position and the second liquid level position (simple average or weighted average) may be used as the liquid level position to be detected this time.
  • control unit 40 outputs the position of the liquid level 91 specified in step S11 to the external device 60 (step S12).
  • the external device 60 includes, for example, an image display such as an LCD (Liquid Crystal Display) or an OLED (Organic Light Emitting Diode), and displays the position of the liquid level 91 on the image display. This is the end of the description of the liquid surface position detection process.
  • the propagation speed of the surface wave propagating through the second portion 10b that contacts the liquid 90 (hereinafter referred to as the second sound velocity) is the first portion 10a that contacts the air. It is known that the velocity is slower than the propagation speed of the surface wave propagating through (hereinafter referred to as the first sound velocity). For this reason, the propagation time (first propagation time, second propagation time) measured by the timer becomes longer as the length L2 of the second portion 10b is longer. That is, the longer the liquid 90 is in the container 80 and the higher the position of the liquid level 91 from the bottom surface of the container 80, the longer the propagation time.
  • composition of the synthetic resin forming the propagating body 10 is not limited as long as the propagation time of the surface wave can be detected, but polyethylene, polystyrene, etc. are adopted in addition to PPS (polyphenylene sulfide). be able to. In addition, it is thought that PPS which can observe the propagation wave of a surface wave is suitable as the said synthetic resin.
  • the control unit 40 detects a propagation time in which the period becomes longer as the liquid contact portion (second portion 10b) becomes longer according to the position of the liquid surface 91 of the liquid 90, and the position of the liquid surface 91 is based on the detected propagation time. Is detected.
  • the position of the liquid level 91 is, for example, the length L2 of the second portion 10b where the propagating body 10 is immersed in the liquid 90, the height of the liquid level 91 from the bottom surface of the container 80, the length L2 or the height of the liquid level 91. What is necessary is just to represent with the value etc. according to.
  • the height of the liquid surface 91 from the bottom surface of the container 80 is the depth of the liquid 90, and is obtained by length L2 + length d (see FIG. 1).
  • the first surface wave W1 and the second surface wave W2 are reflected by the bottom surface portion 16. This causes leakage and loss.
  • the first surface wave W1 and the second surface wave W2 are not reflected by the bottom surface portion 16 and leakage does not occur. Since the attenuation of the surface wave Wr received by the child 20 is small, the S / N ratio can be improved. However, an unnecessary propagation wave U may be generated near the surface wave.
  • FIG. 7 (a) schematically shows an unnecessary propagation wave U.
  • FIG. Wd represents a surface wave sent from the vibrator 20 to the propagating body 10, and Wr represents a surface wave received by the vibrator 20.
  • control unit 40 may execute a liquid surface position detection process for simultaneously generating the first surface wave W1 and the second surface wave W2. At this time, the first and second propagation wave signals are superimposed and observed (received) as propagation wave signals.
  • the liquid surface position detection process will be described with reference to FIG.
  • control unit 40 vibrates the first transmission / reception unit 21 via the transmission / reception circuit 30 to generate the first surface wave W ⁇ b> 1 at the upper end of the main surface part 11.
  • the second transmission / reception unit 22 is vibrated to generate the second surface wave W2 at the upper end of the main surface part 12 (step S101).
  • the control unit 40 sets a timer to an initial value of 0 in order to measure a period from when the process of step S101 is performed until the propagation wave signal is received (step S102).
  • the first and second transmitting / receiving units 21, 22 is a period until the timing of receiving a propagation wave signal, that is, a propagation time.
  • the control unit 40 determines whether or not a propagation wave signal has been received from the transmission / reception circuit 30 (step S103). This determination is performed by the same method as in step S3 described above, and when the propagation wave signal has not been received yet (step S103; No), the control unit 40 updates the timer value of the timer by +1 or the like ( Step S104), the process of step S103 is executed again. Thereby, the control part 40 performs time measurement until a propagation wave signal is received.
  • control unit 40 When receiving the propagation wave signal (step S103; Yes), the control unit 40 stores the current timer value as the propagation time, for example, in the RAM (step S105).
  • control unit 40 specifies the position of the liquid level 91 (liquid level position) based on the propagation time stored in step S105 (step S106).
  • the relationship between the propagation time and the position of the liquid surface 91 is specified in advance by experiments or the like, and the specified relationship is stored in the ROM as a table or an arithmetic expression.
  • the control unit 40 specifies the liquid level position based on the table or arithmetic expression stored in the ROM and the propagation time.
  • control unit 40 outputs the position of the liquid level 91 specified in step S106 to the external device 60 (step S107).
  • the external device 60 displays the position of the liquid level 91 on the image display.
  • the amplitude of the surface wave Wr received by the vibrator 20 is increased. Therefore, the S / N ratio can be further improved.
  • the propagating body 210 according to the second embodiment includes the main surface portion 11 and the main surface portion 12, the side surface portion 13 and the side surface portion 14, the contact portion 15, and the bottom surface portion 16. .
  • the vibrator 220 according to the second embodiment includes the same as the first transmission / reception unit 21 and the second transmission / reception unit 22 as in the first embodiment.
  • a third transmission / reception unit 23 and a fourth transmission / reception unit 24 are provided.
  • the propagating body 210 has a concave portion 17 that is recessed from the contact portion 15 toward the bottom surface portion 16. As shown in FIG. 5B, the recess 17 is located between the main surface portion 11 and the second main surface portion 12 in a side view.
  • the concave portion 17 is a portion that is hollowed out in, for example, a rectangular parallelepiped shape from the contact portion 15 toward the bottom surface portion 16, and includes first to fourth inner side surface portions 17a to 17d and an inner bottom surface portion 17e.
  • the first inner side surface portion 17 a is located on the back side of the main surface portion 11.
  • the second inner side surface portion 17 b is located on the back side of the main surface portion 12.
  • the first inner side surface portion 17a and the second inner side surface portion 17b face each other.
  • the third inner side surface portion 17 c is located on the back side of the side surface portion 13.
  • the fourth inner side surface portion 17 d is located on the back side of the side surface portion 14.
  • the third inner side surface portion 17c and the fourth inner side surface portion 17d face each other.
  • the inner bottom surface portion 17e is located at the bottom of the concave portion 17, and has a rectangular shape in plan view as shown in FIG.
  • FIG. 7B schematically shows a state in which the detection wave D is generated by providing the propagation body 210 with the concave portion 17.
  • the detection wave D indicates a first detection wave D1 or a second detection wave D2 described later.
  • the third wave transmitting / receiving unit 23 generates a first detection wave D1 made of a surface wave or a plate wave in the propagation body 210 and receives the first detection wave D1 reflected by the inner bottom surface part 17e of the recess 17.
  • the fourth transmission / reception unit 24 generates a second detection wave D ⁇ b> 2 composed of a surface wave or a plate wave in the propagation body 210 and receives the second detection wave D ⁇ b> 2 reflected by the inner bottom surface part 17 e of the recess 17.
  • the third transmission / reception unit 23 vibrates by the electric signal supplied from the transmission / reception circuit 30.
  • the vibration of the third transmission / reception unit 23 is transmitted to the propagation body 210, and the first detection wave D1 is generated at the upper end of the first inner side surface portion 17a.
  • the generated first detection wave D1 propagates toward the lower end of the first inner side surface portion 17a, reflects off the inner bottom surface portion 17e, and then propagates toward the upper end of the first inner side surface portion 17a. .
  • the first detection wave D1 that has reached the upper end of the first inner side surface portion 17a vibrates the third transmission / reception unit 23.
  • the third transmission / reception unit 23 converts this vibration into an electric signal and supplies it to the transmission / reception circuit 30.
  • the fourth transmission / reception unit 24 vibrates by the electric signal supplied from the transmission / reception circuit 30.
  • the vibration of the fourth transmission / reception unit 24 is transmitted to the propagation body 210, and the second detection wave D2 is generated at the upper end of the second inner side surface portion 17b.
  • the generated second detection wave D2 propagates toward the lower end of the second inner side surface portion 17b, reflects off the inner bottom surface portion 17e, and then propagates toward the upper end of the second inner side surface portion 17b. .
  • the second detection wave D2 that has reached the upper end of the second inner side surface portion 17b vibrates the fourth transmission / reception unit 24.
  • the fourth transmission / reception unit 24 converts this vibration into an electric signal and supplies it to the transmission / reception circuit 30.
  • the first detection wave D1 received by the third transmission / reception unit 23 and the second detection wave D2 received by the fourth transmission / reception unit 24 depend on the temperature of the propagating body 210 regardless of the position of the liquid surface 91. Changes.
  • the temperature of the propagating body 210 is detected using at least one of the first detection wave D1 and the second detection wave D2, and the detected temperature is converted into a surface wave (the first surface wave W1 and the first detection wave D1). This is used for temperature correction when detecting the two surface waves W2). For this reason, it is not necessary to provide the temperature sensor which consists of the thermistor chip etc. which were provided in the conventional liquid level position detection apparatus.
  • the transmission / reception circuit 30 supplies the third transmission / reception unit 23 with the electrical signal for transmission of the first detection wave D1 to vibrate the third transmission / reception unit 23. Further, it receives an electrical signal supplied from the third transmitting / receiving unit 23 that has received the first detection wave D1, and amplifies and converts the received electrical signal. In addition, the transmission / reception circuit 30 supplies an electric signal for transmission of the second detection wave D2 to the fourth transmission / reception unit 24, and vibrates the fourth transmission / reception unit 24. Also, the electric signal supplied from the fourth transmitting / receiving unit 24 that has received the second detection wave D2 is received, and the received electric signal is amplified and converted.
  • the control unit 40 drives and controls each of the third transmission / reception unit 23 and the fourth transmission / reception unit 24 via the transmission / reception circuit 30.
  • the control unit 40 receives electrical signals from each of the third transmission / reception unit 23 and the fourth transmission / reception unit 24 that are amplified and converted by the transmission / reception circuit 30, and based on the received electrical signals, Detect temperature.
  • the control unit 40 detects the propagation time of each of the first detection wave D1 and the second detection wave D2 by a method similar to the method described in the liquid level position detection process described above.
  • the propagation time of the first detection wave D1 is referred to as a first detection time
  • the propagation time of the second detection wave D2 is referred to as a second detection time.
  • the control unit 40 generates the first detection wave D1 by the third transmission / reception unit 23, and then the third transmission / reception unit 23 receives the first detection wave D1 after being reflected by the inner bottom surface part 17e. Is determined based on the timer value. Then, the specified time is stored in the RAM as the first detection time. Further, based on the timer value, the time from when the fourth transmission / reception unit 24 generates the second detection wave D2 to when the fourth transmission / reception unit 24 receives the second detection wave D2 after being reflected by the inner bottom surface portion 17e. To identify. Then, the specified time is stored in the RAM as the second detection time. The control unit 40 specifies (detects) the temperature of the propagating body 210 based on at least one of the first detection time and the second detection time obtained as described above.
  • the sound velocity of the first detection wave D1 and the second detection wave D2 changes depending on the temperature of the propagating body 210 regardless of the position of the liquid surface 91.
  • the first detection time and the second detection time also change depending on the temperature of the propagating body 210 regardless of the position of the liquid surface 91.
  • the relationship between the first detection time, the second detection time, and the temperature of the propagation body 210 is specified in advance by experiments, and the specified relationship is stored in the ROM as a table or an arithmetic expression.
  • the control unit 40 specifies the temperature of the propagating body 210 based on the table or arithmetic expression stored in the ROM and the first detection time and the second detection time.
  • the control unit 40 uses a table or an arithmetic expression for specifying the temperature of the propagating body 210 based on the first detection time, and uses the temperature of the propagating body 210 based on the first detection time (hereinafter referred to as the first temperature).
  • the temperature of the propagating body 210 based on the second detection time (hereinafter referred to as the second temperature) using a table or an arithmetic expression for identifying the temperature of the propagating body 210 based on the second detection time.
  • the control unit 40 may specify each of the first temperature and the second temperature.
  • the average of the first temperature and the second temperature (simple average or weighted average) may be used as the temperature to be detected this time.
  • the temperature that does not indicate the error value may be set as the temperature to be detected this time.
  • control part 40 performs temperature correction of 1st propagation time and 2nd propagation time based on the temperature of the propagation body 210 specified (detected) as mentioned above.
  • the speed of sound is temperature dependent and changes according to the temperature of the propagating body 210. That is, the first propagation time and the second propagation time also change according to the temperature of the propagation body 210. For this reason, in order to maintain the detection accuracy of the liquid surface position, the temperature correction is necessary.
  • a table configured by associating the temperature of the propagating body 210 with the correction amount and correction coefficient of the propagation time is stored in the ROM in advance, and the control unit 40 refers to the table and determines the specified propagation.
  • a correction amount or correction coefficient corresponding to the temperature of the body 210 may be acquired. And the control part 40 performs the calculation which adds / subtracts the acquired correction amount to each of 1st propagation time and 2nd propagation time, and the calculation which multiplies a correction coefficient, and is 1st propagation time and 2nd propagation time. Time temperature correction may be performed.
  • a table configured by associating the temperature of the propagating body 210 with the correction amount and correction coefficient of the liquid surface position is stored in advance in the ROM and specified based on the first propagation time and the second propagation time.
  • the liquid surface position may be corrected.
  • the control unit 40 is not limited to the table, and stores an expression (may be an approximate expression) representing the temperature dependence of the sound speed in the ROM, and the propagation time or the liquid surface position is stored using the expression.
  • the correction amount and the correction coefficient may be obtained.
  • the temperature correction method for the propagation time and the liquid surface position can be arbitrarily selected from known table construction methods and calculation methods.
  • the above temperature correction process includes the above-described liquid surface position detection process as long as the first detection wave D1 and the second detection wave D2 do not interfere with the first surface wave W1 and the second surface wave W2.
  • the generation timing of the first detection wave D1 and the second detection wave D2 may be made simultaneously with the generation timing of the first surface wave W1 and the second surface wave W2.
  • the temperature correction process may be executed as a process independent of the liquid surface position detection process.
  • the concave portion 17 is cut out in a rectangular parallelepiped shape and the inner bottom surface portion 17e is flat has been described, but the present invention is not limited to this.
  • the inner bottom surface portion 17e of the concave portion 17 may be formed in a U-shaped smooth curved surface that protrudes downward like the bottom surface portion 16 according to the first embodiment.
  • the fourth transmission / reception unit 24 receives the first detection wave D1 transmitted from the third transmission / reception unit 23 to the propagating body 210, and the fourth transmission / reception unit.
  • the liquid level position detection in addition to detecting the detailed position of the liquid level 91 (detecting the height of the liquid level 91 from the bottom surface of the container 80 as described above), what is the position of the liquid level 91. It also includes detecting to which stage the current position of the liquid level 91 belongs, divided into stages. Further, the image displayed on the external device 60 after the liquid level position is detected by the control unit 40 may not indicate the liquid level position itself, but may indicate the amount of the liquid 90 corresponding to the liquid level position.
  • the propagation bodies 10 and 210 are made of synthetic resin, and it is preferable that the propagation time becomes longer as the second portion 10b (liquid contact portion) becomes longer according to the liquid surface position of the liquid 90, and propagates through the second portion 10b. It is preferable that the difference between the speed of the surface wave that travels and the speed of the surface wave that propagates through the first portion 10a (the portion exposed from the liquid 90) becomes more significant.
  • the propagating bodies 10 and 210 may be made of a metal such as aluminum, stainless steel, or steel as long as the liquid level position can be detected by the method described above.
  • the propagating bodies 10 and 210 may be arranged such that the longitudinal direction thereof is parallel to the normal direction of the liquid surface 91 and the longitudinal direction is inclined with respect to the normal direction of the liquid surface 91. Good. Further, a plurality of concave portions or convex portions extending along the traveling direction of the surface wave may be formed on the surface of the propagating bodies 10 and 210 where the surface wave propagates, and the concave and convex portions may be formed on this surface.
  • the type of the liquid 90 whose liquid level position is to be detected is not limited, and water, gasoline, cleaning liquid and the like are arbitrary. Further, the liquid surface 91 may be a gas other than air or a vacuum.
  • the container 80 may be a fuel tank mounted on a vehicle.
  • the liquid 90 becomes a fuel such as gasoline.
  • the propagating bodies 10 and 210 may be attached to, for example, a fuel pumping unit that is attached to the fuel tank and includes a fuel pump that extracts fuel from the fuel tank.
  • PPS polyphenylene sulfide
  • POM polyacetal
  • PBT polybutylene terephthalate
  • PPS examples include linear type, cross-linked type, and anti-cross-linked type. Further, there are those added with fillers (additive materials) such as glass fibers and inorganic fillers. PPS can be used. Surface wave or plate wave propagation state (for example, good S / N ratio, surface due to differences in linear type, cross-linked type, anti-cross-linked type, presence / absence of filler addition, type of filler, etc. The effect on the sound speed of waves or plate waves is considered to be small.
  • Surface waves may be other than Rayleigh waves.
  • the surface wave may be a sound wave having a lower frequency than the ultrasonic wave. Further, the surface wave may not be a pulse wave, and may be a burst wave, for example.
  • the plate wave may be a pulse wave or a burst wave.
  • the liquid surface position detection device 100 described above includes the propagation bodies 10 and 210 in which the ratio of the portion immersed in the liquid 90 changes according to the liquid surface position of the liquid 90 (the position of the liquid surface 91).
  • the first transmitting / receiving unit 21 that generates the first surface wave W1 in the bodies 10 and 210 and receives the second surface wave W2, and the second surface wave W2 in the propagation bodies 10 and 210 and the first surface wave W1
  • the second transmission / reception unit 22 to receive, the propagation time of the first surface wave W1 received by the second transmission / reception unit 22, and the propagation time of the second surface wave W2 received by the first transmission / reception unit 21 And a detection part (for example, control part 40) which detects a liquid level position based on.
  • the propagating bodies 10 and 210 connect the main surface portion 11 (first main surface portion) and the main surface portion 12 (second main surface portion), and the main surface portion 11 and the main surface portion 12, which are in reverse relation to each other, and are curved in a side view. And a bottom surface portion 16 having a shape.
  • the first transmission / reception unit 21 generates a first surface wave W1 propagating through the main surface part 11, and the second transmission / reception unit 22 is transmitted through the main surface part 11 through the bottom surface part 16 and the main surface part 12.
  • the second transmission / reception unit 22 generates a second surface wave W2 that propagates through the main surface portion 12, and the first transmission / reception unit 21 propagates through the main surface portion 12 through the bottom surface portion 16 and the main surface portion 11.
  • the bottom surface portion 16 having a curved shape in the side view is provided, loss due to leakage when the first surface wave W1 and the second surface wave W2 propagate to the bottom surface portion 16 can be reduced. The deterioration of the N ratio can be reduced. As a result, the detection accuracy of the liquid surface position can be improved. Further, since the liquid surface position is detected based on at least one of the propagation time of the first surface wave W1 and the propagation time of the second surface wave W2 received by the first transmission / reception unit 21, it is possible to superimpose noise. Even when the detection accuracy of one propagation time is inferior, the detection accuracy of the liquid level can be improved.
  • the propagation bodies 10 and 210 have the contact part 15 which contacts the 1st transmission / reception part 21 and the 2nd transmission / reception part 22, and the main surface part 11 is a contact part in side view.
  • the main surface portion 12 hangs down from the other end of the contact portion 15 in a side view.
  • the first wave transmitting / receiving unit 21 generates the first surface wave W1 propagating through the main surface part 11 via the contact part 15, and the second wave transmitting / receiving part 22 is transmitted through the contact part 15 to the main surface part 12. 2nd surface wave W2 which propagates is generated.
  • the first transmission / reception unit 21 is provided in contact with the first main surface portion 11, and the second transmission / reception unit 22 is provided in contact with the second main surface portion 12. May be adopted.
  • the first transmission / reception unit 21 and the second transmission / reception unit 22 may simultaneously generate the first surface wave W1 and the second surface wave W2 (the first surface wave W1 by the first transmission / reception unit 21). And the generation of the second surface wave W2 by the second transmission / reception unit 22 may be simultaneous).
  • the propagating body 210 according to the second embodiment is recessed from the contact portion 15 toward the bottom surface portion 16, and has a recess 17 located between the main surface portion 11 and the main surface portion 12 in a side view. With this recess 17, the internal propagation wave U generated from the vibrator 220 to the propagation body 210 can be reduced or eliminated. Thereby, the detection error of liquid level position detection can be reduced.
  • the liquid level position detection apparatus applies a detection wave (at least one of the first detection wave D1 and the second detection wave D2) that is a surface wave or a plate wave to the propagating body 210.
  • a specific transmitting / receiving unit (at least one of the third transmitting / receiving unit 23 and the fourth transmitting / receiving unit 24) to be generated is further provided.
  • the specific transmission / reception unit generates a detection wave propagating through the inner side surface portion of the concave portion 17 via the contact portion 15 and receives the detection wave reflected by the inner bottom surface portion 17e of the concave portion 17 through the inner side surface portion.
  • the detection unit detects the temperature of the propagation body 210 based on the propagation time of the detection wave received by the specific transmission / reception unit. Since it did in this way, it is not necessary to provide the temperature sensor which consists of thermistor chips etc. which were provided in the conventional liquid level position detection apparatus, and reduction of a number of parts is possible.
  • the 1st transmission / reception part 21, the 2nd transmission / reception part 22, and the specific transmission / reception part may generate
  • the generation of the first surface wave W1 by the first transmission / reception unit 21, the generation of the second surface wave W2 by the second transmission / reception unit 22, and the generation of the detection wave by the specific transmission / reception unit may be simultaneous).
  • SYMBOLS 100 Liquid level position detection apparatus 10, 210 ... Propagation body 10a ... 1st part, 10b ... 2nd part 11 ... Main surface part (an example of 1st main surface part) 12 ... Main surface portion (an example of a second main surface portion) DESCRIPTION OF SYMBOLS 13, 14 ... Side surface part 15 ... Contact part 16 ... Bottom part 20, 220 ... Vibrator 21 ... 1st transmission / reception part, 22 ... 2nd transmission / reception part W1 ... 1st surface wave, W2 ... 2nd surface wave 23 ... 3rd transmission / reception part, 24 ... 4th transmission / reception part D1 ... 1st detection wave, D2 ... 2nd detection wave 30 ... Transmission / reception circuit 40 ... Control part

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  • Physics & Mathematics (AREA)
  • Acoustics & Sound (AREA)
  • Electromagnetism (AREA)
  • Thermal Sciences (AREA)
  • Fluid Mechanics (AREA)
  • General Physics & Mathematics (AREA)
  • Measurement Of Levels Of Liquids Or Fluent Solid Materials (AREA)

Abstract

La présente invention concerne un dispositif de détection de position de niveau de liquide ayant une bonne précision de détection de position de niveau de liquide. Le dispositif de détection de position de niveau de liquide est pourvu d'un corps de propagation 10 dans lequel le rapport d'une partie de celui-ci qui est immergée dans un liquide varie en fonction de la position du niveau du liquide, d'une première partie d'émission/réception 21, d'une seconde partie d'émission/réception 22 et d'une partie de détection pour détecter la position du niveau du liquide sur la base du temps de propagation d'une première onde de surface W1 et/ou d'une seconde onde de surface W2. Le corps de propagation 10 comporte une partie de surface inférieure 16 qui relie une partie de surface principale 11 et une partie de surface principale 12 et forme une surface incurvée en vue latérale. La première partie d'émission/réception 21 génère une première onde de surface W1 se propageant à travers la partie de surface principale 11, et la seconde partie d'émission/réception 22 reçoit la première onde de surface W1 se propageant à travers la partie de surface inférieure 16 et la partie de surface principale 12 par l'intermédiaire de la partie de surface principale 11. La seconde partie d'émission/réception 22 génère une seconde onde de surface W2 se propageant à travers la partie de surface principale 12, et la première partie d'émission/réception 21 reçoit la seconde onde de surface W2 se propageant à travers la partie de surface inférieure 16 et la partie de surface principale 11 par l'intermédiaire de la partie de surface principale 12.
PCT/JP2019/005488 2018-02-28 2019-02-15 Dispositif de détection de position de niveau de liquide WO2019167660A1 (fr)

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JP2020503385A JP7076072B2 (ja) 2018-02-28 2019-02-15 液面位置検出装置

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JP2018-034911 2018-02-28
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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4213337A (en) * 1977-09-13 1980-07-22 The Marconi Company Limited Liquid level sensing devices
US4920796A (en) * 1987-11-13 1990-05-01 Robert Bosch Gmbh Tank level meter
WO1990010849A1 (fr) * 1989-03-09 1990-09-20 Robert Bosch Gmbh Detecteur acoustique de niveau de fluide
JP2004028592A (ja) * 2002-06-21 2004-01-29 Nippon Soken Inc 液体計測装置
JP2004117301A (ja) * 2002-09-27 2004-04-15 Denso Corp 振動式液面検出器およびそれを用いた液面検出装置

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4213337A (en) * 1977-09-13 1980-07-22 The Marconi Company Limited Liquid level sensing devices
US4920796A (en) * 1987-11-13 1990-05-01 Robert Bosch Gmbh Tank level meter
WO1990010849A1 (fr) * 1989-03-09 1990-09-20 Robert Bosch Gmbh Detecteur acoustique de niveau de fluide
JP2004028592A (ja) * 2002-06-21 2004-01-29 Nippon Soken Inc 液体計測装置
JP2004117301A (ja) * 2002-09-27 2004-04-15 Denso Corp 振動式液面検出器およびそれを用いた液面検出装置

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JP7076072B2 (ja) 2022-05-27

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