JP2002013967A - Ultrasonic water level gauge and method for measuring water level by ultrasonic - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ultrasonic water level gauge and a method for measuring water level by ultrasonic capable of precisely measuring water level without correcting differences of temperature, atmospheric pressure, wind or the like. SOLUTION: The ultrasonic water level gauge comprises an ultrasonic transmitter-receiver 1, a timer means 4a for measuring time until transmitted ultrasonic is received after reflected at an object, a controlling means 4b for controlling sensitivity of the ultrasonic receiver 1b, a calculating means 4c for calculating a distance to the reflecting object based upon the measured result and reflecting bodies 6, 7, 8 made of cylindrical hollow pipes placed at a plurality of positions whose distances from the ultrasonic transmitter 1a are known. Ultrasonic is transmitted toward a water surface and echo pulse reflected at each reflected body 6, 7, 8 is received for measuring time. By measuring at a plurality of patterns having different receiving sensitivities, a highly precise measurement is possible without receiving influences of temperature, atmospheric pressure or wind.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for measuring a water level such as a tide level and a wave height using an ultrasonic wave, and a measuring method.

[0002]

2. Description of the Related Art In a port or the like, a water level such as a tide level and a wave height is constantly measured and used as data for weather observation or used to prevent an unexpected disaster. In general, many instruments such as foos type tide gauges and hydraulic tide gauges have been used for tide level observation.In recent years, airborne ultrasonic wave height gauges have been installed in front of quays, etc. Observation of long-period waves such as vibrations is increasing. This is because a water level gauge using airborne ultrasonic waves has a feature that it can catch a rapidly changing water level fluctuation.

[0003] The principle is that an ultrasonic transmitter / receiver in which an ultrasonic transmitter and a receiver are integrated is installed about several meters above the water surface, and the ultrasonic wave is transmitted from the ultrasonic transmitter / receiver to the water surface. It receives the ultrasonic wave reflected by, measures the time required during the time, and detects the position of the water surface. Since the position of the ultrasonic transceiver is fixed, a water level such as a changing tide level can be measured. Further, since the measuring instruments are installed not on the water but on the ground, they are easy to handle, and can perform 24-hour measurement and real-time calibration measurement.

However, since the speed of the ultrasonic wave varies depending on the temperature, even if the time from transmission to reception is the same,
The water level will vary depending on the temperature. So, usually,
A thermometer is installed at the measurement site, the temperature at the time of measurement is measured, and the temperature is corrected by a calculation formula. This method assumes that the temperature in the ultrasonic signal path is constant, but in fact, near the sea surface,
Since it is a boundary between air and water, the temperature gradient is considered to be large, and the accuracy of correction is not reliable.

In addition, not only the temperature but also the atmospheric pressure affects the measurement. To improve the measurement accuracy, it is necessary to measure and correct both the temperature and the atmospheric pressure, and the correction becomes very complicated. In addition, the water surface is not stationary like a mirror surface, but also has waves and swells, and also ripples due to wind, and the way of reflection is different depending on these, and stable measurement is difficult. Furthermore, there are fluctuations due to the wind. Since the wind has a component in the XYZ directions and constantly fluctuates, this measurement is almost impossible as a practical matter.
The manufacturing cost of the device is very high.

In order to solve the above problem, it is good to increase the sensitivity of receiving the ultrasonic wave reflected on the water surface. However, in this case, the influence of noise increases, and it is difficult to accurately recognize the water surface. Conversely, if the sensitivity is low, there is a problem that the echo pulse cannot be received.

[0007]

SUMMARY OF THE INVENTION The present invention has been conceived in view of the above facts, and does not require correction of temperature, air pressure and wind, and furthermore, an ultrasonic type water level meter capable of measuring water level with high accuracy. And a method for measuring a water level by ultrasonic waves.

[0008]

In order to achieve the above object, an ultrasonic water level meter according to the present invention comprises an ultrasonic transmitter and an ultrasonic wave transmitted from the ultrasonic transmitter which is reflected by an object. An ultrasonic receiver, a time measuring means for measuring a time from transmission to reception, an arithmetic means for calculating a distance to a reflecting object based on the measurement result, and a plurality of distances known from the ultrasonic transmitter. And a plurality of reflectors arranged at locations.

[0009] Alternatively, an ultrasonic transmitter, an ultrasonic receiver for receiving an ultrasonic wave transmitted by the ultrasonic transmitter reflected by an object, and a time measuring means for measuring a time from transmission to reception. Output / sensitivity adjusting means capable of adjusting at least one of the output of the transmitted ultrasonic wave and the sensitivity of the ultrasonic receiver; a calculating means for calculating a distance to the reflecting object based on the reception result; And one or more reflectors arranged at one or more locations at known distances.

Or, an ultrasonic transmitter, an ultrasonic receiver for receiving an ultrasonic wave transmitted from the ultrasonic transmitter reflected by an object, and a time measuring means for measuring a time from transmission to reception. The ultrasonic receiver measures the echo pulse received and calculates the time when the output reaches a predetermined ratio with respect to the maximum output of the echo pulse as the reception time of the echo pulse,
It is characterized by having arithmetic means for calculating the distance to the reflecting object based on the calculation result, and one or more reflectors arranged at one or more locations where the distance from the ultrasonic transmitter is known.

Or, an ultrasonic transmitter, an ultrasonic receiver for receiving an ultrasonic wave transmitted from the ultrasonic transmitter reflected by an object, and a time measuring means for measuring a time from transmission to reception. Calculating means for calculating the rise time of the echo pulse from a plurality of points on the echo pulse received by the ultrasonic receiver and calculating the distance to the reflecting object based on the calculation result; and the distance from the ultrasonic transmitter is known. And one or more reflectors arranged at one or more locations.

Or, an ultrasonic transmitter, an ultrasonic receiver for receiving an ultrasonic wave transmitted from the ultrasonic transmitter reflected by an object, and a time measuring means for measuring a time from transmission to reception. Output / sensitivity adjusting means capable of adjusting at least one of the output of the transmitted ultrasonic wave and the sensitivity of the ultrasonic receiver, and calculating the rise time of the echo pulse from a plurality of points on the echo pulse received by the ultrasonic receiver. And a calculating means for calculating the distance to the reflective object based on the calculation result, and a plurality of reflectors arranged at a plurality of locations at a known distance from the ultrasonic transmitter.

[0013] The reflector may be a circular hollow pipe, or the ultrasonic transmitter and the ultrasonic receiver may be an ultrasonic transmitter and receiver integrally formed in a donut shape. A conical reflector may be provided on the outside, and the angle between the reflection surface of the reflector and the center axis of the ultrasonic transceiver may be set to approximately 45 °.

According to the method of measuring the water level by ultrasonic waves of the present invention, an ultrasonic pulse is transmitted from above the water surface toward the water surface, and one or more distances from the ultrasonic transmitter that are arranged above the water surface and are known from the ultrasonic transmitter are known. A method of measuring the water level by reflecting the echo pulse reflected by the reflector and the water surface as the object to be measured, reflected by the water surface and each reflector, and measuring the time from transmission to reception by the reception. In addition, at least one of the transmission output and the reception sensitivity of the ultrasonic wave is changed, and the measurement is repeated a plurality of times. Calculate the rise time of the echo pulse from a plurality of points on the echo pulse,
The distance to the reflection object may be calculated based on the calculation result.

Alternatively, an ultrasonic transmitter transmits an ultrasonic pulse from above the water surface toward the water surface, and one or more reflectors arranged above the water surface and having a known distance from the ultrasonic transmitter. A method of measuring the water level by receiving the echo pulse reflected by the water surface as the object to be measured, reflected by the water surface and each reflector, and measuring the time from transmission to reception by each echo pulse, By transmitting the ultrasonic pulse a plurality of times while shifting the time, receiving an echo pulse corresponding to the transmitted pulse in each time, obtaining a difference between an echo pulse of one time and an output of a corresponding echo pulse of another time. It is characterized by specifying echo pulses from the water surface.

Note that a series of echo pulses received each time may be regarded as one echo pulse curve, and the difference between one echo pulse curve and another echo pulse curve may be obtained. One round and another round may be adjacent but not necessarily adjacent.

[0017]

Embodiments of the present invention will be described below with reference to the drawings. 1A and 1B are views showing a state in which an ultrasonic water level gauge of the present invention is installed, wherein FIG. 1A is a side view and FIG. 1B is a front view. In FIG. 1, reference numeral 1 denotes an ultrasonic transmitter / receiver, which includes an ultrasonic transmitter 1a, an ultrasonic receiver 1b for receiving an echo pulse which is reflected when an emitted ultrasonic wave hits an object, and an ultrasonic transmitter. Output / sensitivity adjusting means 1c capable of adjusting at least one of the output of the ultrasonic wave transmitted by the detector 1a and the sensitivity of the ultrasonic receiver 1b. The ultrasonic transceiver 1 is fixed in the air, for example, at the tip of a beam 3 that extends horizontally from a quay 2 of a port or the like. The two dotted lines that open in a fan shape in the figure indicate the propagation range of the transmitted ultrasonic waves.

On the ground, a ground station 4 is installed, in which a timer 4a for measuring the time from transmission of an ultrasonic wave to reception of an echo pulse, and driving of an ultrasonic transmitter 1a and an ultrasonic receiver 1b. Control means 4b for the entire apparatus such as control
And a calculating means 4c for calculating the distance to the reflecting object from the measurement result. The ground station 4 uses a computer such as a personal computer for its main part.

Reflectors 6, 7, 8 are arranged between the ultrasonic transceiver 1 and the water surface 5 at known distances L1, L2, L3. For these reflectors 6, 7, 8 circular hollow pipes are used. As a reflector, a plate-shaped reflector has a higher echo intensity. However, when a plate-shaped reflector is used, the plate surface must be accurately directed to the ultrasonic transmitter / receiver 1 and is slightly inclined. If this occurs, the echo will not return to the ultrasonic receiver 1b, and reception will not be possible. Further, since the reflectors 6, 7, and 8 project in a horizontal direction from the quay 2 or the struts, the reflectors become cantilevered beams. Measurement cannot be performed. On the other hand, when a circular hollow pipe is used, the problem of orientation as in the case of a plate does not occur, and the bending can be reduced even in a cantilever structure, and stable measurement can be performed.

In the embodiment of the present invention, the reflectors 6, 7, 8 and three reflectors are used.
2, L3 can be set accurately. FIG.
As shown in (a), the lengths may be different,
As shown in FIG. 1B, the ultrasonic transceiver 1 is arranged so as not to be linearly overlapped with the ultrasonic transmitter / receiver 1, so that the echo can be reliably received. However, an echo from a reflector of about 1 m or less from the ultrasonic transmitter / receiver 1 is referred to as a short-range sound field, and the pressure of the sound wave is disturbed. In addition, any of the reflectors must be within the propagation range of the ultrasonic wave transmitted from the ultrasonic transceiver 1 (the range between the two dotted lines in FIG. 1).

Further, the inner and outer diameters of the pipes of the reflectors 6, 7, and 8 do not need to be all the same, and the outer diameter and the inner diameter may be different. In general, the strength of the echo pulse decreases as the distance from the ultrasonic transceiver 1 increases. For example, if the inner and outer diameters of the reflectors 6, 7, 8 are increased as the distance increases, the intensity of all echo pulses can be made substantially the same. Conversely, when the inner and outer diameters of the reflectors 6, 7, 8 are the same, the closer the reflectors 6, 7, 8 and the water surface 5, the lower the intensity of the echo pulse. On the other hand, since the echo pulse from the water surface 5 is basically constant, if the inner and outer diameters of the reflectors 6, 7, 8 are the same, the echo pulse from the reflector 8 closest to the water surface 5 and the water pulse 5 This makes it easier to distinguish the echo pulse from the signal.

The accuracy of the measurement can be improved if the reflector used for such a purpose is placed as far away from the ultrasonic transmitter / receiver 1 as possible and near the water surface.
However, if it is installed near the water surface and the tide level changes,
It will be submerged. Therefore, in the present invention, a plurality of reflectors 6, 7, 8 are provided. Even if the lower reflectors 7 and 8 are submerged, if the upper reflector 6 is not submerged, the measurement can be performed based on this.

Next, a method for measuring the height of the water surface 5 with the ultrasonic water level meter of the present invention will be described. When an ultrasonic pulse is transmitted from the ultrasonic transmitter 1a shown in FIG.
The transmitted ultrasonic pulse is reflected by the reflectors 6, 7, 8 and the water surface 5.
And is reflected by the ultrasonic receiver 1b as an echo pulse.
Come back to.

FIG. 2A shows a waveform a of a pulse transmitted from the ultrasonic transmitter 1a and a waveform 6 of an echo pulse reflected by the reflectors 6, 7, and 8 and received by the ultrasonic receiver 1b.
FIG. 6 is a diagram showing waveforms 5 a of echo pulses reflected at a, 7 a and 8 a and a water surface 5. The vertical axis represents pulse intensity, and the horizontal axis represents time. The time on the horizontal axis can be easily converted to distance by multiplying by the speed of sound.

In the embodiment of the present invention, since the diameters of the reflectors 6, 7, 8 are the same, the waveforms 6a, 7 of the echo pulses are formed.
a and 8a become lower gradually. On the other hand, since the height of the water surface 5 is almost constant, the intensity of the echo pulse 5a coming from the water surface 5 can be considered to be substantially constant. Therefore, the waveform 8a of the echo pulse from the reflector 8 depends on the intensity of the echo pulse.
Or the waveform 5a of the echo pulse from the water surface 5 can be easily identified.

The timing of receiving the echo pulse by the ultrasonic receiver 1b is 2.9 m / mm for a sound speed of 340 m / sec.
When the echo pulse is measured at this interval, measurement on the order of 1 mm is possible. If the distance from the ultrasonic transceiver 1 to the water surface 5 is 10 m, 0.1se
The entire measurement range can be measured at about c. In the first measurement, the measurement is performed at an interval of 2.94 μsec over the entire range. When the positions of the water surface 5, the reflectors 6, 7, and 8 can be grasped, the gates G1, G2, G
3, G4 is set, and only the inside of these gates will be measured from the next time.

FIG. 2A shows a case where the sensitivity of the ultrasonic receiver 1b is maximized. In this case, all of the waveforms 6a, 7a, 8a of the echo pulses from the reflectors 6, 7, 8 and the waveform 5a of the echo pulse from the water surface 5 are detected.

FIGS. 2B to 2D show how the sensitivity of the ultrasonic receiver 1b is gradually reduced.
In (b), the waveforms of the echo pulses of the reflectors 6, 7, 8 are 6
b, 7b, and 8b, and the waveform 5b of the echo pulse from the water surface 5 is also small. 2 (c) and 2 (d), the echo pulses from the reflectors 6, 7, 8 cannot be measured. The waveform of the echo pulse from the water surface 5 is also gradually reduced to 5c and 5d.

As described above, the sensitivity of the ultrasonic receiver 1b is set to a plurality of sensitivities and, for example, is changed to four patterns as in the embodiment, and (a) → (b) → (c) → (d) →
(A) The measurement is repeated as follows. If it takes 0.1 sec to measure one pattern as described above, 4
The pattern ends in 0.4 sec. Even if 0.1 sec is added as a processing time to this time, the entire sampling time is 0.5 sec, and the water level can be measured in a short cycle, and can be used not only for tide level measurement but also for wave height measurement.

As described above, by performing measurement of a plurality of patterns while changing the receiving sensitivity, it is possible to eliminate the influence of noise when the sensitivity is too high. If the sensitivity is too high and relatively strong echo pulses such as the water surface 5 and the nearest reflector 6 are saturated, the data is rejected, and data when all the echo pulses are not saturated is used. You can also.

Also, by synthesizing a plurality of patterns of echo pulses, it is possible to measure the water level under various conditions. For example, even when the water surface 5 rises and the bottom reflector 8 and the water surface 5 overlap, the water surface can be detected in the case of the pattern shown in FIG. 2C or 2D.
By superimposing on the images of (a) and (b), the water level can be measured.

As described above, by changing the reception sensitivity of the ultrasonic receiver 1b and measuring the echo pulses in a plurality of patterns, the water level can be reliably measured. Further, according to the measurement method of the present invention, even if there is a change in temperature, pressure, or wind,
There is no need to perform complicated correction. In other words, if echo pulses are measured in multiple patterns while changing the receiving sensitivity,
The echoes from the reflectors 6, 7, and 8 and the echoes from the water surface 5 can always be captured. Since the distances to the respective reflectors 6, 7, and 8 are known, the distance to the water surface 5 is proportional. This is because it can be easily calculated by a method such as distribution. The distance to the water surface 5 may be obtained by a proportional expression from each of the reflectors 6, 7, and 8, and an average may be calculated.
It may be determined only from the reflector 8 closest to the water surface.

In the above embodiment, the receiving sensitivity of the ultrasonic receiver 1b is changed, but the output of the ultrasonic transmitter 1a may be changed. However, changing the receiving sensitivity simplifies the configuration of the device.

FIG. 3 is a diagram for explaining the pulse measuring method of the present invention. In the present invention, the transmission pulse and each echo pulse are measured, but the specification of the reception timing of these pulses is not easy. For example, when the reception timing of the pulse 10 shown in FIG. 3A is set to the rising position 10a of the pulse 10 and to the intermediate position 10b of the pulse height, an error of T2−T1 = ΔT is obtained. appear.

In this embodiment, in order to prevent such an error, the timing of the pulse is set to a position where the output reaches half the height of the pulse. In this way, as shown in pulses 11 and 12 in FIG. 3B, even if the rising slope of the pulse has a large or small gradient, the positions 11a and 12a where the output reaches 1/2 of the pulse height are This is because T becomes the same, and it can be determined that the pulses have the same timing, and an error in the reception timing due to the shape of the pulse can be eliminated.

However, when the pulse 13 is saturated as shown in FIG. 3 (c), the timing is measured by this method, and when the output is at the position 13a where the output reaches half of the pulse height, Assuming that the pulse is T3, the pulse is actually like a dotted line, and T4 corresponding to a half height 13b to the peak of the dotted line is an accurate time, and an error occurs.

Although the above error may be ignored, in the present invention, the reception sensitivity is changed and measurement is performed in a plurality of patterns. Therefore, it is assumed that the pattern is saturated as shown in FIG. Also, a pattern that does not reach saturation appears in a pattern in which the reception sensitivity is lowered, and the above problem can be solved.

In the above embodiment, since the time when the pulse height reaches 1/2 is set as the reception time of the pulse, the reception time corresponding to the shortest path is not detected. To detect the reception time corresponding to the shortest route,
It is necessary to specify the time at which the pulse starts to rise.
However, the rising portion of the pulse is easily affected by the contamination of noise, and the rising time cannot be specified from the pulse waveform in some cases.

Therefore, in the embodiment of the present invention, the calculating means 4
The following arithmetic processing is performed in c. It is assumed that the pulse draws a waveform like a pulse 15 shown in FIG. At this time, the calculating means 4c finds a point 15a at which the height of the pulse 15 reaches 25% and a point 15b at which the height of the pulse 15 reaches 50% on the waveform of the pulse 15. Then, a point 1 where a straight line 16 connecting these two points 15a and 15b intersects the time axis
7 is obtained, and the coordinate of this point 17 on the time axis is set as the rising time.

However, the method described above is based on FIG.
Strictly speaking, an error Δt occurs slightly with respect to the actual rise time 15c as shown in FIG. Therefore, a method shown in FIG. 4B has been devised as a method with higher accuracy. According to this method, the rising portion 18 in the first half of the pulse 15 has almost the same pattern of curves,
This is to take advantage of the fact that it can be complemented by the following curve. That is, first, as in the case of the straight line 16 described above,
Point 1 when the calculating means 4c reaches 25% of the height of the pulse 15
5a and a point 15b at which 50% is reached are obtained on the waveform of the pulse 15. Next, by inputting the points 15a and 15b into the equation of the curve given in advance, the curve 18 is specified, and the rise time can be obtained from the point 15c where the curve 18 and the time axis intersect. As the equation of the above-mentioned “predetermined curve”, it is possible to use the equation in some commercially available software.

The points 15a and 15b are defined as a point at which the height of the pulse 15 reaches 25% and a point at which the height reaches 50%.
In particular, it is not limited to a value of 25% or 50%,
Any numerical value may be used. Also, without being limited to two points,
A curve that can be obtained in advance by obtaining three or more points and obtaining a straight line 16 by the least square method or calculating an arc connecting the three points
It may be used instead of.

As described above, since the reflector 8 is located farthest from the ultrasonic transmitter 1a, the echo pulse is weakest among the three reflectors. On the other hand, the water surface 5
When the water surface is flat like a mirror surface, a strong echo pulse is reflected, but usually, since it varies variously from a ripple to a large swell,
The echo pulse reflected by the water surface 5 may be small. In general, when any one of the reflectors 6, 7, 8 and the water surface 5 are close to each other, whether the echo pulse is from the reflectors 6, 7, 8 or the echo pulse from the water surface 5 is determined. In some cases, the distinction becomes very difficult.

A method of determining the water surface 5 in such a case will be described with reference to FIGS. First, a fixed time interval (for example, 0.1 sec interval) in the ultrasonic transmitter 1a
, An ultrasonic pulse is transmitted a plurality of times, and a series of echo pulses reflected from the reflectors 6, 7, 8 and the water surface 5 are received by the ultrasonic receiver 1b. FIGS. 5 (a) to 5 (f) are diagrams showing a series of echo pulse curves A, B, C, D, E and F showing the echo pulses received in this manner.
The vertical axis is pulse intensity, and the horizontal axis is time (distance). Here, the transmission output and the reception sensitivity are kept constant.

In FIGS. 5A to 5F, l, m,
n is an echo pulse curve A, B, C, D,
Echo pulses from reflectors 6, 7, 8 appearing in E and F, and h1 to h6 indicate echo pulses from respective water surfaces 5.

If the transmission output from the ultrasonic transmitter 1a and the reception sensitivity of the ultrasonic receiver 1b are constant, the echo pulses from the reflectors 6, 7, and 8 shown in FIGS. The waveforms l, m, and n are almost always constant in each round.
On the other hand, since the water surface 5 is constantly changing, the waveforms h1 to h6 of the respective echo pulses are different from each other.

Therefore, as shown in FIGS. 6 (a) to 6 (e), the echo pulse curve A for a certain round and the round adjacent thereto is shown.
And B, B and C, C and D, D and E, and E and F. Then, the waveforms l, m, and n of the echo pulse almost overlap,
It can be seen that only the waveforms h1 to h6 of the echo pulse do not overlap.

FIGS. 7A to 7E show differences between adjacent echo pulse curves, that is, BA, CB, and D-.
It is the diagram which calculated C, ED, and FE. As can be seen from these figures, except for the echo pulse from the water surface 5,
It becomes almost 0, and new pulses h2-h1, h3-h2, h4-h3, h are applied only to the portion of the echo pulse from the water surface 5.
5-h4, h6-h5 are formed. Therefore, the timing at which these pulses are generated is determined by one of the pulse outputs described above.
/ 2 or 25% and 50% to determine the rising timing.

Since the waveforms h1 to h6 of the echo pulses from the water surface 5 shown in FIG. 5 have relatively large outputs, it is possible to detect the water surface 5 without using the above method. However, when the above method is used, even when the waveforms h1 to h6 of these echo pulses become substantially equal to the waveform n of the echo pulse from the reflector 8, the water surface 5 can be easily detected.

H (i) is defined as h (i) -h (i-1), where h (i) is the echo pulse from the water surface 5 measured at the i-th time.
If> 0, the water surface 5 tends to rise, and h (i) -h
If (i-1) <0, the water surface 5 is in a downward trend, and if this is used, the wave height and waveform of the water surface 5 can be obtained.

The method for specifying the water surface 5 described with reference to FIGS. 5, 6, and 7 can be applied to the method for measuring while changing the reception sensitivity described with reference to FIG. However, in this case, the waveforms of the adjacent echo pulse curves are inappropriate for obtaining the difference because the sensitivity of the ultrasonic receiver 1b has changed. Therefore, the difference from the echo pulse curve at the time of the previous measurement at the same sensitivity (although not necessarily limited to the previous time) is obtained.

The water level measurement method of the present invention can be applied to both wave height observation and tide level observation. However, in order to reproduce the waveform, it is desirable that sampling be performed at a high speed at intervals of 0.1 to 0.5 sec, and the observation accuracy is not required as high as that of a tide gauge. On the other hand, high accuracy is required for tide level observation, but the sampling interval may be about 5 seconds. Therefore, the level of the echo pulse is set as a reference and small-level echo pulses or saturated echo pulses are cut. It is also possible to measure.

FIG. 8 shows another embodiment of the ultrasonic transceiver. In the ultrasonic transceiver 20 shown in the figure, transmission and reception of ultrasonic waves are performed by the vibrator 21. The vibrator 21 has a vertically long donut shape or a hollow cylindrical shape, and vibrates in a radial direction like a respiratory motion. Ultrasonic waves are transmitted in the horizontal direction (outer peripheral direction) by the vibration of the vibrator 21. A conical reflector 22 is attached to the outside of the vibrator 21, and the ultrasonic wave transmitted from the transducer 21 travels in the horizontal direction, is reflected by the reflector 22, and is directed directly downward (water surface). Turn around. In the reception of the reflected signal, the path of the ultrasonic wave is the same, and only the direction is reversed.

The reflector 22 shown in FIG. 8 is open at an angle of 45 ° from the central axis of the vibrator 21. Therefore, the path length of the ultrasonic wave 21a emitted from the upper side of the vibrator 21 and the ultrasonic wave 21b emitted from the lower side of the vibrator 21 are the same, and the virtual measurement origin 23 can be concentrated at one point. As a result, the transmission pulse and the echo pulse are narrow,
The shape becomes very sharp, and the error can be reduced. Note that a protective umbrella 2 for blocking an ultrasonic signal transmitted and received directly without passing through the reflector 22 is provided at the lower end of the vibrator 21.
4 are provided.

[0054]

According to the present invention as described above,
An ultrasonic transmitter, an ultrasonic receiver that receives the ultrasonic wave transmitted by the ultrasonic transmitter being reflected by an object, a time measuring unit that measures the time from transmission to reception, and based on the measurement result. It is assumed that there are arithmetic means for calculating the distance to the reflecting object, and a plurality of reflectors arranged at a plurality of locations where the distance from the ultrasonic transmitter is known, so that echo pulses from the plurality of reflectors are measured. By doing so, the distance to the water surface can be accurately measured. Further, correction of temperature, pressure, and wind is not required. Further, since the reflectors are provided at a plurality of locations, even if the lower one is submerged, the measurement can be continued based on the upper one.

Further, if a control means is provided which is capable of adjusting at least one of the output of the transmitted ultrasonic wave and the sensitivity of the ultrasonic receiver, the output of the ultrasonic wave or the sensitivity of the ultrasonic receiver can be changed to provide a plurality of control units. By repeating the measurement twice, accurate measurement can be performed without the influence of the pulse reaching saturation or the influence of noise.

Alternatively, if the ultrasonic receiver measures the echo pulse received and calculates the time when the output reaches a predetermined ratio with respect to the maximum output of the echo pulse as the reception time of the echo pulse, It is possible to accurately detect the reception time of the echo pulse without being affected by the reception sensitivity or the like.

If the rising time of the echo pulse is calculated from a plurality of points on the echo pulse received by the ultrasonic receiver, the shortest path to the reflector can be detected, and more accurate measurement can be performed.

If the reflector is a circular hollow pipe, the orientation of the reflector and the intensity of the echo become irrelevant.
Mounting of the reflector becomes easy. In addition, even if the reflector has a cantilever structure, the amount of deflection at the tip can be reduced,
Stable measurement is possible without shaking due to wind or the like.

If there are a plurality of hollow pipes having the same diameter, the reflector closest to the water surface is farthest from the ultrasonic transceiver, so that the output of the echo pulse is small. The distinction becomes clear.

The ultrasonic pulse is transmitted a plurality of times while shifting the time, a series of echo pulses corresponding to the transmitted pulse is received each time, and an output of an echo pulse curve formed by a series of echo pulses of a certain time and another pulse are output. If the echo pulse from the water surface is specified by determining the difference from the output of the echo pulse curve, even when the reflector and the water surface are very close, and the echo pulse from the water surface is small,
The echo pulse from the water surface can be clearly grasped.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of an ultrasonic water level meter of the present invention;
(A) is a side view, (b) is a front view.

FIG. 2 is a diagram illustrating a method for measuring a water level with the apparatus of FIG.

FIG. 3 is a diagram illustrating pulse measurement timing.

FIG. 4 is a diagram illustrating a method for measuring a rise time of a pulse.

FIG. 5 is a diagram showing an echo pulse curve in which ultrasonic pulses are transmitted at regular time intervals and echoes from a plurality of reflectors and the water surface 5 are received.

FIG. 6 is a diagram showing adjacent ones of the echo pulse curves of FIG. 5 in an overlapping manner.

FIG. 7 is a diagram illustrating a difference between adjacent ones of the echo pulse curves of FIG. 5;

FIG. 8 is a diagram illustrating the configuration of another embodiment of the ultrasonic transceiver.

[Explanation of symbols]

 1a Ultrasonic Transmitter 1b Ultrasonic Receiver 1c Output / Sensitivity Adjusting Means 4a Timekeeping Means 4b Control Means 4c Calculation Means 5 Water Surface 6,7,8 Reflector 20 Ultrasonic Transmitter 21 Transducer 22 Reflector A, B, C , D, E, F echo pulse curve

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Norihiko Nagai 3-1-1 Nagase, Nagase, Yokosuka City, Kanagawa Prefecture (72) Inventor Yasunori Watanabe 2-131-5 Hayashi, Tokorozawa City, Saitama Prefecture No. In the Tokorozawa Plant of Kyowa Shoko Co., Ltd. (72) Masaaki Namama 2-131-5 Hayashi, Tokorozawa City, Saitama Prefecture Inside of the Tokorozawa Plant Kyowa Shoko Co., Ltd. 131-5 Kyowa Shoko Co., Ltd.Tokorozawa Plant (72) Inventor Toshihiro Takayama 2-131-5 Kobayashi, Tokorozawa City, Saitama Prefecture Kyowa Shoko Co., Ltd.Tokorozawa Plant (72) Inventor Michiru Kozono 2-131-5 Kyowa Shoko Co., Ltd. Tokorozawa Plant F-term (reference) 2F014 AA04 AA05 FB01

Claims (10)

[Claims] 1. An ultrasonic transmitter, an ultrasonic receiver for receiving an ultrasonic wave transmitted by the ultrasonic transmitter reflected by an object, and a time measuring means for measuring a time from transmission to reception.
An ultrasonic water level, comprising: arithmetic means for calculating a distance to a reflecting object based on a measurement result; and a plurality of reflectors arranged at a plurality of locations having a known distance from the ultrasonic transmitter. Total. 2. An ultrasonic transmitter, an ultrasonic receiver for receiving an ultrasonic wave transmitted by the ultrasonic transmitter reflected by an object, and a time measuring means for measuring a time from transmission to reception.
Output / sensitivity adjusting means capable of adjusting at least one of the output of the transmitted ultrasonic wave and the sensitivity of the ultrasonic receiver, and a calculating means for calculating the distance to the reflecting object based on the reception result,
An ultrasonic water level gauge, comprising: one or more reflectors arranged at one or more locations at a known distance from an ultrasonic transmitter. 3. An ultrasonic transmitter, an ultrasonic receiver for receiving an ultrasonic wave transmitted by the ultrasonic transmitter reflected by an object, and a time measuring means for measuring a time from transmission to reception.
The ultrasonic receiver measures the echo pulse received and calculates the time when the output reaches a predetermined ratio with respect to the maximum output of the echo pulse as the reception time of the echo pulse, and based on the calculation result, calculates the time until the reflection object. An ultrasonic water level meter, comprising: an arithmetic unit for calculating a distance; and one or more reflectors arranged at one or more locations where the distance from the ultrasonic transmitter is known. 4. An ultrasonic transmitter, an ultrasonic receiver for receiving an ultrasonic wave transmitted by the ultrasonic transmitter reflected by an object, and a time measuring means for measuring a time from transmission to reception.
Calculating means for calculating the rise time of the echo pulse from a plurality of points on the echo pulse received by the ultrasonic receiver and calculating the distance to the reflecting object based on the calculation result; and the distance from the ultrasonic transmitter is known. And an at least one reflector disposed at one or more locations. 5. An ultrasonic transmitter, an ultrasonic receiver for receiving an ultrasonic wave transmitted by the ultrasonic transmitter reflected by an object, and a time measuring means for measuring a time from transmission to reception. Output / sensitivity adjusting means capable of adjusting at least one of the output of the transmitted ultrasonic wave and the sensitivity of the ultrasonic receiver, and calculating the rise time of the echo pulse from a plurality of points on the echo pulse received by the ultrasonic receiver. , An arithmetic unit that calculates a distance to a reflective object based on the calculation result, and a plurality of reflectors arranged at a plurality of locations whose distance from the ultrasonic transmitter is known, an ultrasonic wave type having Water level gauge. 6. The ultrasonic water level gauge according to claim 1, wherein said reflector is a circular hollow pipe. 7. An ultrasonic transmitter / receiver wherein the ultrasonic transmitter and the ultrasonic receiver are integrally formed in a donut shape,
Outside the ultrasonic transceiver, a conical reflector is provided,
7. The ultrasonic type water level meter according to claim 1, wherein an angle between a reflection surface of the reflector and a central axis of the ultrasonic transceiver is substantially 45 degrees. 8. An ultrasonic pulse is transmitted from above the water surface toward the water surface, and one or two or more reflectors located above the water surface and having a known distance from the ultrasonic transmitter and an object to be measured. A method of receiving an echo pulse reflected by the water surface and reflected by the water surface and each reflector, measuring the time from transmission to reception by the reception, and measuring the water level, wherein the transmission output of the ultrasonic wave Water level measurement method using ultrasonic waves, wherein the measurement is repeated a plurality of times while changing at least one of the sensitivity and the reception sensitivity. 9. The water level measurement by ultrasonic waves according to claim 8, wherein a rise time of the echo pulse is calculated from a plurality of points on the echo pulse, and a distance to the reflecting object is calculated based on the calculation result. Method. 10. An ultrasonic pulse is transmitted from above the water surface toward the water surface, and one or more reflectors located above the water surface and having a known distance from the ultrasonic transmitter and an object to be measured. A method of receiving an echo pulse reflected by the water surface and reflected by the water surface and each reflector, measuring the time from transmission to reception by the reception, and measuring the water level, wherein the ultrasonic pulse is timed. Multiple times while shifting, receiving the echo pulse corresponding to the transmitted pulse in each time, calculating the difference between the echo pulse of one time and the output of the corresponding echo pulse of another time, the echo pulse from the water surface A method for measuring a water level by using an ultrasonic wave, comprising: