JP2009281729A - System and method for diagnosing attached state of ultrasonic sensor, and ultrasonic type level switch and ultrasonic type level gage using the system and method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a system and a method for diagnosing the attached state of an ultrasonic sensor which improve measuring stability by improving the capability of detecting a function of self-diagnosing the attached state of the ultrasonic sensor, and also an ultrasonic type level switch and an ultrasonic level gage which utilize the system and the method. <P>SOLUTION: An operation of self-diagnosing the attached state of the ultrasonic sensor is performed in such a manner that a received wave changeover switch SW-R is made to operate by a CPU and the ultrasonic sensor 21 and the ultrasonic sensor 22 which are provided adjacently to a tank are made to operate as a sensor for transmission and a sensor for reception. In the case that a reverberation echo in a prescribed time range cannot be detected by the ultrasonic sensor 22 after the driving of the ultrasonic sensor 21 is started, either of the two ultrasonic sensors is determined to be disengaged, and when the reverberation echo can be detected, the attached state of the two ultrasonic sensors is determined to be favorable. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  TECHNICAL FIELD The present invention relates to an ultrasonic sensor mounting state diagnosis system and method installed on an outer surface of a tank, etc., an ultrasonic liquid level switch and an ultrasonic liquid level gauge using the system, and more particularly to mounting of an ultrasonic sensor. The present invention relates to a system and method with improved self-diagnosis function detection capability, and an ultrasonic liquid level switch and ultrasonic liquid level meter with improved self-diagnosis function detection capability with respect to attachment of an ultrasonic sensor.

  In agricultural fields such as factories and horticultural horticulture, A heavy oil is burned as a heat source, and it is widely used for generating steam and warm air for heating. These heat sources are required to operate stably at low cost for a long period of time, so that A heavy oil can be selected and installed as appropriate depending on consumption, from small tanks of about 1.9 kL installed outdoors to large tanks of 20 kL, etc. Has been. These tanks meet the installation requirements stipulated by the Fire Service Law, and floats and balance weights are connected to the A heavy oil with a rope via a pulley at the top of the tank as a level gauge to check the remaining amount of the A heavy oil. There are many fishing bottle drop-type liquid level gauges.

  However, the above-described liquid level gauge is a mechanical type, and unless the operating parts are constantly greased, there is a drawback that friction is increased and an accurate liquid level cannot be displayed. In addition, when trying to increase the delivery efficiency of A heavy oil, someone has to check the remaining amount visually, the compatibility with telemetry monitoring etc. is low, there is a sudden change in weather conditions, a sudden increase in production of products, etc. In general planned delivery and on-call delivery by an end user, A heavy oil is cut off, and an economic loss may occur.

  As other methods to check the remaining amount, various attempts have been made, such as a liquid level meter using aerial ultrasonic waves from the upper surface, a hydrometer that measures the water head pressure with a pressure gauge, and continuously measures the remaining amount of liquid, The upper surface of the A heavy oil tank is provided with a downward slope from the center of the tank to the periphery for the purpose of making it difficult for rain to enter the tank. In order to remove the drain efficiently, some small tanks have a funnel shape at the bottom center. For these reasons, it is difficult to perform additional work on the tank in operation, such as an additional work on the tank is required for the aerial ultrasonic method from the top surface, and the bottom drain is necessary for the pressure method. There are problems such as high processing costs even in tanks.

In addition, the consumption of heavy fuel oil A is never checked for the remaining liquid level in minutes, and is usually managed on a daily basis, and it is sufficient to manage on a time basis at the shortest. An ultrasonic sensor is installed on the outer surface of the tank to satisfy the balance of surface, cost, and installation, and the presence of liquid is measured by emitting ultrasonic waves from the side and measuring the ultrasonic propagation time to the opposite tank inner wall. An ultrasonic liquid level switch has been devised (see, for example, Patent Document 1).
Japanese Patent Laid-Open No. 08-136320

  There are two types of ultrasonic liquid level switches: reflective type and transmissive type, but the reflective type is advantageous in terms of installation and cost. In order to stably operate the reflective ultrasonic liquid level switch, ultrasonic waves can be emitted at right angles to the opposite tank wall surface when there is liquid in the tank, and the reflected echo on the opposite tank wall surface can be reliably captured. In order to prevent erroneous determination, it is desirable to take a margin so that the duration of the reverberation wave is less than half of the tank diameter in terms of distance when there is no liquid in the tank.

  In addition, the reflective ultrasonic liquid level switch is equipped with a transmission / reception ultrasonic sensor on the side of the tank wall. When there is liquid, the reflected echo from the tank facing wall can be recognized, and the drive reverberation echo length when there is no liquid is present. It must be attenuated below the reflected echo detection level at the time.

By the way, in the reflection type ultrasonic liquid level switch, since the ultrasonic sensor is attached to the tank wall surface, there is a problem that the liquid level cannot be detected when the ultrasonic sensor falls off the tank wall surface.
For this reason, having a self-diagnosis function to determine whether the ultrasonic sensor is attached or not is important for stable operation as a liquid level detector. The diagnosis method is based on the presence or absence of liquid in the tank. It is necessary to use an unrecognized determination method, and it is conceivable to determine the attachment state of the ultrasonic sensor by monitoring the duration of the reverberation echo of the ultrasonic sensor.
When a transmission / reception type ultrasonic sensor is used, the reverberation echo is when the ultrasonic sensor falls off <with the ultrasonic sensor mounting liquid in the tank <with no ultrasonic sensor mounting part liquid, but the reverberation echo is the tank steel plate thickness and tank shape Since it changes depending on the driving conditions of the ultrasonic sensor, it has been difficult to stably and steadily detect the drop of the ultrasonic sensor.

  Also, for example, in the agricultural field such as horticulture, it is used as a heat source only when the outside air temperature is lowered, and depending on the crop, there is no fuel consumption and tank level fluctuations for about half a year before and after summer. Disappear. If the remaining fuel level in the tank falls below the level detector mounting position and enters the non-heating period, it will be in the absence of liquid for about half a year. It was difficult to ensure the stability of the self-diagnosis function.

  The above measures the liquid level propagation delay time of the ultrasonic echo transmitted to the liquid part interface in the tank not only from the ultrasonic liquid level switch but also from the ultrasonic sensor installed at the tank bottom. There was a similar problem in the ultrasonic liquid level gauge to be measured.

  The present invention has been made in view of the above circumstances, and an ultrasonic sensor mounting state diagnostic system that improves measurement stability by improving the self-diagnosis function detection capability of the mounting state of an ultrasonic sensor. In addition to improving the measurement stability of the ultrasonic sensor by applying the system and method to an ultrasonic liquid level switch and an ultrasonic liquid level gauge, An ultrasonic liquid level gauge is provided for an ultrasonic liquid level switch that is improved in maintainability by clearly indicating pass / fail.

  According to the first aspect of the present invention, an ultrasonic sensor for transmission is provided in a container that contains a liquid, an ultrasonic sensor for reception is provided adjacent to the ultrasonic sensor for transmission, and the ultrasonic wave for transmission is provided. By receiving the propagation of the ultrasonic wave emitted from the sensor by the receiving ultrasonic sensor, it is determined whether or not the ultrasonic wave is propagated, and from the presence or absence of the ultrasonic wave propagation, the transmission ultrasonic sensor and the receiving wave are detected. It is characterized by diagnosing the mounting state of the ultrasonic sensor.

  According to a second aspect of the present invention, in the ultrasonic liquid level switch, an ultrasonic sensor for transmitting and receiving is installed on a side surface outside the tank, and the presence or absence of liquid in the tank is determined based on the presence or absence of reflection echo from the tank facing wall surface. Propagation of ultrasonic waves by providing an ultrasonic sensor for reception in close proximity to the ultrasonic sensor for combined use and receiving the propagation of ultrasonic waves emitted from the ultrasonic sensor for combined transmission and reception by the ultrasonic sensor for reception The presence / absence of the ultrasonic wave is discriminated, and the mounting state of the ultrasonic sensor for transmission and reception and the ultrasonic sensor for reception is diagnosed from the presence or absence of propagation of the ultrasonic wave.

  According to a third aspect of the invention, in the second aspect of the invention, the transmitting / receiving ultrasonic sensor and the receiving ultrasonic sensor are integrally formed.

  According to a fourth aspect of the present invention, there is provided an ultrasonic liquid level meter for measuring a liquid level based on a reception timing of an ultrasonic liquid level echo transmitted to a liquid surface by installing a transmission / reception ultrasonic sensor on a bottom portion outside the tank. In the above, the reception ultrasonic sensor is provided in the proximity of the transmission / reception ultrasonic sensor, and the propagation of the ultrasonic wave emitted from the transmission / reception ultrasonic sensor is received by the reception ultrasonic sensor, It is characterized in that the presence / absence of ultrasonic wave propagation is discriminated, and the mounting state of the ultrasonic sensor for transmission / reception and the ultrasonic wave sensor for reception is diagnosed from the presence / absence of the ultrasonic wave propagation.

  The invention of claim 5 is the invention of claim 4, wherein the transmitting / receiving ultrasonic sensor is installed at the bottom of the bottom outside the tank, and the receiving ultrasonic sensor has a curved surface at the bottom outside the tank. The liquid level is detected by receiving the ultrasonic level ultrasonic wave emitted from the ultrasonic sensor for transmission / reception with the ultrasonic sensor for reception.

  According to a sixth aspect of the present invention, in the fourth or fifth aspect of the invention, the transmitting / receiving ultrasonic sensor and the receiving ultrasonic sensor are integrally formed.

  According to a seventh aspect of the present invention, there is provided a step of transmitting ultrasonic waves from an ultrasonic sensor provided in a container that contains a liquid, and an ultrasonic sensor for reception provided adjacent to the ultrasonic sensor from the ultrasonic sensor. Receiving the propagation of the emitted ultrasonic wave, determining the presence or absence of the propagation of the ultrasonic wave, and diagnosing the attachment state of the ultrasonic sensor and the receiving ultrasonic sensor from the presence or absence of the propagation of the ultrasonic wave. It is characterized by having.

  According to the ultrasonic sensor attachment diagnostic system and method according to the present invention, the reception ultrasonic sensor monitors the ultrasonic output of the drive ultrasonic sensor, whereby the attachment state of the ultrasonic sensor can be determined stably. Further, according to the ultrasonic liquid level switch according to the present invention using this, the ultrasonic output of the driving ultrasonic sensor is monitored by the reception ultrasonic sensor, so that the ultrasonic wave is detected regardless of the presence or absence of liquid in the tank. Since the sensor mounting state can be determined stably, the operational stability can be improved. In particular, when a liquid-free situation has continued for a long time, it has been difficult to determine whether or not the product has been stable, but this can be solved.

  In addition, according to the ultrasonic level gauge according to the present invention, the same effect as the ultrasonic level switch described above can be obtained, and since the reverberation echo of the reception ultrasonic sensor is small, the minimum detection distance can be shortened. Become.

  Hereinafter, the ultrasonic sensor system according to the present invention will be described first with respect to an embodiment applied to the ultrasonic liquid level switch of the A heavy oil tank. However, the ultrasonic type liquid level switch is limited to the liquid type and tank shape. Not a thing. An ultrasonic liquid level meter that detects the liquid level based on the reception timing of the ultrasonic wave level reflection echo transmitted to the liquid interface will be described later.

  The present invention is realized by adding a switching circuit and one ultrasonic sensor of the same type to an ultrasonic liquid level switch using a transmission / reception ultrasonic sensor and adding a control algorithm of CPU software. .

  FIG. 1 is a diagram showing a case where an ultrasonic liquid level switch according to an embodiment of the present invention is provided in a small A heavy oil tank. A float 8 floats on the liquid level 30 of the A heavy oil liquid 2, and a liquid level gauge including an upper pulley 6, a connecting wire 7, and a weight / display pointer 9 is provided. As the liquid level 30 moves up and down, the pointer 9 also moves up and down, and the remaining amount of liquid can be read according to which position of the remaining amount scale 10 the pointer 9 is on. The tank structure is a structure in which flat steel plates are rolled and upper and lower funnel steel plates are welded, and a drain valve 4 is provided at the center of the weld line 5 and the lower steel plate. The upper steel plate is provided with an inspection port 3.

  Here, the ultrasonic sensor unit 20 is provided on the side steel plate of the small A heavy oil tank 1, and by operating a control unit 31 connected to the ultrasonic sensor unit 20, the ultrasonic sensor unit 20 can be moved into the tank. The ultrasonic wave is emitted to the tank and the ultrasonic wave reflected by the inner wall of the tank is received to detect the installation state of the ultrasonic sensor unit 20 and the presence of the A heavy oil liquid at the position where the ultrasonic sensor unit 20 is mounted. Yes.

FIG. 4 shows an example of the sensor unit 20 of the ultrasonic liquid level switch according to the present invention.
Ultrasonic sensors 21 and 22 are pressed against a side steel plate of the A heavy oil tank 1 by a permanent magnet 23 via a wave spring 24. A sensor sheet 26 is provided between the steel plate and each of the ultrasonic sensors 21 and 22 in order to achieve acoustic coupling and thermal coupling. A sensor cable 25 is provided for connection to the control unit 31.
The sensor sheet 26 is obtained by dispersing inorganic fine powder in silicone rubber. The sensor unit 20 is integrated with a base plate 27 in order to secure the installation position of the ultrasonic sensors 21 and 22 and the installation workability. The base plate 27 is made of silicone rubber or NBR rubber and has appropriate flexibility.

FIG. 5 shows a circuit block diagram of an ultrasonic liquid level switch according to the present invention. Note that the circuit block diagram is the same even in an ultrasonic liquid level gauge except that the software processing of the CPU is different. Ultrasonic sensors 21 and 22 are attached to the A heavy oil tank 1 and connected to the control unit 31 by a sensor cable 25.
In FIG. 5, the ultrasonic sensors 21 and 22 are shown up and down for convenience, but the actual mounting direction is such that the two ultrasonic sensors 20 and 21 of the sensor unit 20 are arranged horizontally as shown in FIGS. Install as follows. This makes it easier for both sensors to receive ultrasonic echoes on the opposing wall surface.
Further, as will be described later, one ultrasonic sensor 21 is used as a transmission / reception sensor and the other ultrasonic sensor 22 is used as a reception sensor.

When the presence or absence of the liquid level 30 in the tank 1 is confirmed, the reception wave changeover switch SW-R is deactivated, and the ultrasonic sensor 21 is operated as a transmission / reception sensor. The drive circuit DRV is activated by the signal from the T terminal of the CPU, the ultrasonic sensor 21 is driven at the frequency of the tank steel plate pass band, and the ultrasonic echo reflected from the opposite wall surface of the tank is amplified and shaped by the amplifier circuit AMP. The delay time until arrival at the R terminal of the CPU is measured.
Further, the resistance value of the built-in thermistor THR of the ultrasonic sensor 21 is input to the CPU A / D terminal via the temperature conversion circuit and converted into a temperature value. The CPU calculates the distance to the opposing wall surface using the delay time measurement value, the temperature measurement value, and the ultrasonic wave propagation sound speed that the CPU has in advance. This operation is repeated a plurality of times, and it is determined whether the averaged distance value is within ± 20% of the tank diameter, for example. If the distance is within the determination range, it is determined that there is liquid.

In the self-diagnosis operation of the ultrasonic sensor attached state, the reception wave changeover switch SW-R is operated by the CPU, and the ultrasonic sensor 21 is operated as a transmission sensor and the ultrasonic sensor 22 is operated as a reception sensor.
FIG. 6 is a diagram illustrating the driving waveform of the ultrasonic sensor and the reception waveforms of the reflected echo and the reverberant echo under various conditions. In FIG. 6, in order to facilitate comparison of echo waveforms, the reception waveform of the reception sensor 22 during the transmission / reception operation of the ultrasonic sensor 21 when the SW-R is not in operation and the reception sensor 22 when the reception wave changeover switch SW-R is in operation. Is shown on the same chart.

FIG. 6A shows the reflected echo waveform and the reverberant echo waveform when both the ultrasonic sensors 21 and 22 are well acoustically coupled with the tank steel plate and there is liquid in the tank up to the position where the ultrasonic sensor unit is attached. . In this case, the reverberation echo is small for both the sensors 21 and 22, and the reflection echo is large and good.
As described above, by correcting the time from the driving of the sensor 21 until the reflection echo is obtained with the temperature measurement value, the distance to the tank opposing wall surface is calculated, and if this distance is within the determination range, there is liquid. Judgment can be made. It is also possible to determine this distance by the time until a reflected echo is obtained.

Next, both the ultrasonic sensors 21 and 22 are well acoustically coupled to the tank steel plate, and the reflected echo waveform and the reverberant echo waveform when there is no liquid in the tank up to the position where the ultrasonic sensor unit is attached are shown in FIG. ). In this case, the reverberant echo becomes a little larger and reaches the time zone of the reflected echo slightly.
Accordingly, it can be determined that there is no liquid when a reflection echo having a predetermined size cannot be obtained within the time required for the ultrasonic wave to reciprocate to the tank facing wall.

  Next, although the ultrasonic sensor 22 is well acoustically coupled with the tank steel plate, FIG. 6C shows a reflected echo waveform and a reverberant echo waveform when the ultrasonic sensor 21 is detached from the tank. In this case, regardless of the presence or absence of liquid in the tank, the reception waveform of the ultrasonic sensor 21 is only self-reverberation, and the reception waveform of the ultrasonic sensor 22 has neither reverberation echo nor reflection echo. Therefore, compared with the case where only the ultrasonic sensor 21 is used as a transmission / reception sensor, it is possible to avoid erroneously determining that there is no liquid from only the presence of the reverberant echo of the ultrasonic sensor 21.

  Further, although the ultrasonic sensor 21 is well acoustically coupled with the tank steel plate, the reflected echo waveform and the reverberant echo waveform when the ultrasonic sensor 22 is detached from the tank and there is liquid in the tank are shown in FIG. ). The reception waveform of the ultrasonic sensor 21 has a small reverberation echo and a good reflection echo as in FIG. 6A, but the reception waveform of the ultrasonic sensor 22 has neither a reverberation echo nor a reflection echo.

  In this case, since the ultrasonic sensor 21 is acoustically coupled to the tank steel plate, it is possible to detect the presence or absence of liquid in the tank. However, the ultrasonic sensor 22 is detached from the tank for some reason. When the reflected echo cannot be detected from the ultrasonic sensor 21, it is difficult to determine whether there is no liquid or whether the ultrasonic sensor 21 has been removed from the tank. Therefore, it is necessary to confirm the mounting state of the sensor unit 20 in advance.

  From the above, the self-diagnosis operation of the sensor mounting state is performed by operating the reception wave changeover switch SW-R by the CPU to operate the ultrasonic sensor 21 as a transmission sensor and the ultrasonic sensor 22 as a reception sensor. After the start of driving, the sensor reverberation time range, specifically, the presence or absence of the reverberation echo of the ultrasonic sensor 22 after 50 to 100 μS can be confirmed, so that the sensor mounting state can be reliably determined. Specifically, when the reverberation echo in the predetermined time range cannot be detected by the ultrasonic sensor 22, it is determined that one of the two ultrasonic sensors is disconnected, and when the reverberation echo can be detected, both ultrasonic waves are detected. It is determined that the sensor mounting state is good.

  As described above, the ultrasonic wave transmitted from the transmitting ultrasonic sensor is monitored by the nearby receiving ultrasonic sensor, so that both ultrasonic sensors and the tank steel plate are stably coupled regardless of the presence or absence of liquid in the tank. Can be confirmed. Then, by switching the circuit, the transmitting ultrasonic sensor is operated as a transmission / reception sensor, and the presence or absence of liquid is confirmed by confirming the presence or absence of the reflection echo.

Next, the ultrasonic sensor mounting state diagnostic system according to the present invention was applied to an ultrasonic liquid level gauge that detects the liquid level based on the reception timing of the ultrasonic reflection echo transmitted to the liquid interface. The case will be described.
2 and 3 are examples of a bulk storage tank for LP, which is a sealed high-pressure vessel that can withstand internal pressure. The horizontal type of FIG. 2 and the vertical type of FIG. 3 have a liquid level 12 of LP gas inside, but the liquid type and tank shape are not limited as long as they are ultrasonic level gauges.

In the ultrasonic liquid level gauge, in the case of the horizontal bulk storage tank 11 of FIG. 2, the sensor unit 20 is attached to the bottom of the bulk storage tank. At this time, the ultrasonic sensor 21 that is operated as a transmission / reception sensor for measuring the liquid level is directly below the horizontal bulk storage tank 11 (the lowest part in the 6 o'clock direction), and the reception ultrasonic sensor 22 is close to the circumferential direction of the bulk storage tank. Let it install.
In addition, in the vertical bulk storage tank 13 of FIG. 3, the ultrasonic sensor 21 is mounted directly below (the lowest part in the 6 o'clock direction) as in the horizontal bulk storage tank 11 of FIG. It is free as long as it is close to the sensor 21.
The ultrasonic sensors 21 and 22 may be integrated as a sensor unit 20 as shown in FIG. Reference numeral 31 denotes a control unit.

  In the ultrasonic liquid level gauge, the reflected echo on the tank facing wall of the ultrasonic sensor drive waveform and the reflected echo and reverberant echo received waveforms shown in FIG. Thus, the reception waveform of the reflection echo and the reverberation echo is almost the same as in the case of the ultrasonic liquid level switch.

The state shown in FIG. 6A is a normal operation state, and the sensor mounting state can be confirmed by confirming the reverberation echo of the ultrasonic sensor 22 as in the case of the ultrasonic liquid level switch.
That is, the ultrasonic sensor 22 is well acoustically coupled to the tank steel plate, but the reflected echo waveform and the reverberant echo waveform when the ultrasonic sensor 21 is detached from the tank are the same as those shown in FIG. The ultrasonic sensor 21 is well acoustically coupled to the tank steel plate, but the reflected echo waveform and the reverberant echo waveform when the ultrasonic sensor 22 is detached from the tank are the same as those shown in FIG.

  The measuring method of the distance to the liquid level by the ultrasonic liquid level gauge is not described in detail because a known method can be used. However, if the sensor mounting state can be confirmed, the reception wave changeover switch SW-R is switched to switch the supersonic level. By operating the acoustic wave sensor 21 as a transmission / reception sensor, the distance to the liquid level can be measured.

In the present embodiment, since the ultrasonic sensor 22 can operate as a reception sensor, the reverberation echo of the ultrasonic sensor 22 is smaller than that of the ultrasonic sensor 21 performing a transmission / reception combined operation. If the value is lower than the minimum detection distance, the minimum detection distance can be reduced by operating the reception wave selector switch SW-R.
This is because the ultrasonic sensors 21 and 22 are arranged on a curved surface, so that the ultrasonic waves from the ultrasonic sensor 21 for transmission are reflected by the liquid surface 30 and reach the ultrasonic sensor 22 for reception. This is due to the fact that the sensitivity of the reflected echo is ensured and the reverberation echo is reduced.

The ultrasonic sensor 21 for both transmission and reception and the ultrasonic sensor 22 for reception can be of the same specification, but the ultrasonic sensor 22 for reception is an ultrasonic wave transmitted by the ultrasonic sensor 21 for both transmission and reception. Any ultrasonic sensor can be used as long as it can monitor sound waves, and the ultrasonic sensors 21 and 22 can be provided with different specifications in consideration of downsizing and the like.
Furthermore, if the AMP circuit block can be realized at a lower cost than the reception wave changeover switch SW-R, the ultrasonic sensor 22 is connected to another port of the CPU via the AMP circuit, and the reception signals from the ultrasonic sensors 21 and 22 are processed in software. It is also possible to switch to

  As described above, in the ultrasonic level gauge according to the present invention, the ultrasonic wave transmitted by the transmission / reception type ultrasonic sensor is monitored by the nearby receiving ultrasonic sensor, so that both the ultrasonic sensor and the tank steel plate are acoustically coupled. In addition, it is possible to accurately measure the distance to the liquid interface by switching the circuit.

It is a figure which shows the case where the ultrasonic type liquid level switch which concerns on one Embodiment of this invention is provided in the small A heavy oil tank. It is a figure which shows the case where the ultrasonic type liquid level gauge which concerns on one Embodiment of this invention is provided in the LP gas horizontal type bulk storage tank. It is a figure which shows the case where the ultrasonic type liquid level gauge which concerns on one Embodiment of this invention is provided in the LP gas tank type bulk storage tank. It is a figure which shows the sensor unit of the ultrasonic type liquid level switch and ultrasonic type liquid level system which concern on one Embodiment of this invention. 1 is a circuit block diagram of an ultrasonic liquid level switch and an ultrasonic liquid level gauge according to an embodiment of the present invention. It is a waveform which shows the example of reverberation and a reflective echo at the time of applying the ultrasonic sensor system which concerns on one Embodiment of this invention to an ultrasonic-type liquid level switch thru | or an ultrasonic liquid level meter.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Small A heavy oil tank, 2 ... A heavy oil liquid, 3 ... Inspection port, 4 ... Drain valve, 5 ... Welding wire, 6 ... Pulley, 7 ... Wire, 8 ... Float, 9 ... Weight and indication pointer, 10 ... Liquid level scale, 11 ... Horizontal bulk tank, 12 ... LP gas liquid level, 13 ... Vertical bulk tank, 20 ... Sensor unit, 21, 22 ... Ultrasonic sensor, 23 ... Permanent magnet, 24 ... Wave spring, 25 ... Sensor cable, 26 ... sensor sheet, 27 ... base plate, 30 ... liquid level, 31 ... control unit.

Claims (7)

  An ultrasonic sensor for transmission is provided in a container containing the liquid, and an ultrasonic sensor for reception is provided adjacent to the ultrasonic sensor for transmission, and an ultrasonic wave emitted from the ultrasonic sensor for transmission is provided. By receiving the propagation with a receiving ultrasonic sensor, it is determined whether or not the ultrasonic wave is propagated, and from the presence or absence of the ultrasonic wave propagation, the transmission ultrasonic sensor and the receiving ultrasonic sensor are attached. An ultrasonic sensor mounting state diagnosis system characterized by   In the ultrasonic liquid level switch that installs an ultrasonic sensor for transmission and reception on the side surface outside the tank and determines the presence or absence of liquid in the tank based on the presence or absence of reflection echo from the tank facing wall, close to the ultrasonic sensor for transmission and reception An ultrasonic sensor for reception is disposed and the ultrasonic wave emitted from the ultrasonic sensor for transmission / reception is received by the ultrasonic sensor for reception, thereby determining the presence / absence of ultrasonic wave propagation, An ultrasonic liquid level detection switch characterized by diagnosing the mounting state of an ultrasonic sensor for both transmission and reception and an ultrasonic sensor for reception from the presence or absence of ultrasonic propagation.   The ultrasonic liquid level gauge according to claim 2, wherein the transmission / reception ultrasonic sensor and the reception ultrasonic sensor are integrally formed.   In the ultrasonic liquid level meter that measures the liquid level based on the reception timing of the ultrasonic level echo transmitted to the liquid level by installing an ultrasonic sensor for transmission / reception on the bottom outside the tank, An ultrasonic sensor for reception is provided in close proximity to the ultrasonic sensor, and the propagation of the ultrasonic wave emitted from the ultrasonic sensor for transmission / reception is received by the ultrasonic sensor for reception, thereby confirming the presence / absence of the ultrasonic wave propagation. An ultrasonic liquid level gauge characterized by determining and diagnosing the mounting state of an ultrasonic sensor for both transmission and reception and an ultrasonic sensor for reception from the presence or absence of propagation of the ultrasonic wave.   The transmitting / receiving ultrasonic sensor is installed at the bottom of the bottom outside the tank, and the receiving ultrasonic sensor is disposed adjacent to the curved surface of the bottom outside the tank, and is emitted from the transmitting / receiving ultrasonic sensor. 5. The ultrasonic liquid level gauge according to claim 4, wherein the liquid level is detected by receiving an ultrasonic level echo with a receiving ultrasonic sensor.   6. The ultrasonic liquid level gauge according to claim 4, wherein the transmitting / receiving ultrasonic sensor and the receiving ultrasonic sensor are integrally formed.   A step of transmitting ultrasonic waves from an ultrasonic sensor provided in a container containing liquid; and a propagation of ultrasonic waves emitted from the ultrasonic sensor by a receiving ultrasonic sensor provided adjacent to the ultrasonic sensor. A step of receiving, a step of determining presence / absence of propagation of the ultrasonic wave, and a step of diagnosing the attachment state of the ultrasonic sensor and the ultrasonic sensor for reception from the presence / absence of propagation of the ultrasonic wave. Acoustic sensor mounting state diagnosis method.

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