JPS6365898B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus for measuring water temperature in a predetermined depth underwater using ultrasonic waves.

This invention utilizes the phenomenon that an ultrasonic beam emitted into water generates a volume reverberant echo proportional to the sound wave intensity at that point. That is, the ultrasonic wave is focused on a predetermined focal point, and a strong level volumetric reverberant echo is generated and received at that point.

This will be explained below with reference to the drawings.

In Figure 1, 1 is the transducer 3 and the focal length is
This is an ultrasonic transducer consisting of an ultrasonic lens 4 set at l ₁ . 2 has a vibrator 5 and a focal length of l ₂
This is an ultrasonic transducer consisting of an ultrasonic lens 6 set at (l ₁ ). The ultrasonic transducers 1 and 2 are mounted, for example, at the same horizontal position on the bottom of the ship with an appropriate interval between them. If ultrasonic waves of different frequencies are used, they may be placed at the same location, but if they are of the same frequency, it is better to space them slightly apart to prevent interference.

Now, when an ultrasonic pulse is transmitted from the above-mentioned transducer 1, and immediately after that it enters the reception state, a volume reverberation echo from the focal point _F1 , which has a higher level than the volume reverberation echo level of each point sequentially obtained, is generated. is received (see FIG. 2a), and the time t ₁ from transmission to reception is determined from the received signal. That is, in seawater,
The speed of sound v at T°C is determined by the experimental formula as v(T)=1448.6+4.618T, so 2l ₁ =(1448.6+4.618T)t ₁ ...(1).

Similarly, ultrasonic pulses are transmitted from the transducer 2,
If t ₂ is the time until the volume reverberation echo is received from focal point F ₂ (see Figure 2 b), then 2l ₂ = (1448.6 + 4.618T) t ₂ ...(2), and the above From equations (1) and (2), 2(l ₂ - l ₁ ) = (1448.6 + 4.618T) (t ₂ - t ₁ ) If we rearrange this regarding T, we get T = 1/4.618 {2(l ₂ - l ₁ )／t ₂ −t ₁ −1448.6}…
...(3), and the depth at this time is L=1/2 (l ₁ + l ₂ ) ...(4).

FIG. 3 shows an example of a circuit that embodies the water temperature measuring method described above. In the figure, 7 is a transducer 1,
2 is a transmission trigger generation circuit which sends out a transmission trigger pulse to excite signal 2, and 8 and 9 are transmission/reception switching circuits. Reference numerals 10 and 11 are amplification and detection circuits that amplify and detect the volume reverberation echoes received by the transducers 1 and 2, respectively. 12 and 13 are the amplification and detection circuits 10
This is a detection circuit that slices, detects, and shapes signals based on volume reverberation echoes from each of the high-level focal points F ₁ and F ₂ among the signals obtained in steps F 1 and F 2 . 14 and 15 are timers that measure the time (t ₁ , t ₂ in FIG. 2) from the generation of the transmission trigger pulse from the transmission trigger generation circuit 7 to the extraction of the shaped signal obtained by each detection circuit 12 and 13. be. 16 calculates the water temperature by calculating equations (3) and (4) based on the measurement time data t ₁ , t ₂ obtained by the timers 14 and 15 and the preset focal length data l ₁ , l ₂ . This is an arithmetic circuit that calculates T and depth L. In the above, the water temperature T is derived from the fact that since l ₂ - _{l 1} is a very small distance, the water temperature is considered to be constant, that is, the speed of sound is constant within that very small distance.

As described above, according to the present invention, the water temperature at a predetermined depth underwater, which could not be measured conventionally, can be remotely measured using an extremely simple method and configuration.

It is known that the speed of sound increases by 1.75 m/s per 100 m of depth, so if the above increase is taken into account as the speed of sound at the depth L, more accurate water temperature measurement becomes possible.

Further, as a method of concentrating the ultrasonic waves at one point, it is possible to achieve this not only by using an ultrasonic lens but also by arranging a large number of transducers and adjusting the delay amount of each one, for example. FIG. 4 is a configuration diagram showing an example thereof. In the figure, 17 is a phase setting circuit in which the amount of delay phase of each vibrator 19(1) to 19(n) is set so that the directivity directions set by adjacent vibrators all intersect at one point (focal point). be. The setting amount is variable, and the focal length can be changed by changing the setting amount. A delay circuit 18 provides a predetermined delay to each vibrator based on the amount set by the phase setting circuit 17. 19(1)
to 19(n) is a group of vibrators arranged in a line.

In another embodiment, the delay means is not necessary if the arrangement position of the transducer is adjusted in advance by the ultrasonic propagation distance corresponding to the delay amount (for example, in an arc shape).

[Brief explanation of drawings]

FIG. 1 shows a transducer used in the present invention. FIG. 2 is a signal waveform diagram showing the state of transmission and reception by the transducer shown in FIG. 1 above.
FIG. 3 is a circuit diagram showing one embodiment of the present invention. FIG. 4 shows another embodiment of the transducer.

Claims (1)

[Claims] 1. A first transducer having a first sonic focal length; a second transducer having a second sonic focal length; and receiving waves by the first transducer. a first detection circuit that detects a volume reverberant echo generated at a first acoustic focal length that is received by a second transducer; a second detection circuit that detects ultrasonic waves; a first clock that measures the time from when the first transducer transmits the ultrasonic wave to when the first detection circuit detects the ultrasonic wave; a second clock that measures the time from the time of sound wave transmission to the time of detection in the second detection circuit; and the measurement time obtained by the first and second clocks and the first and second sound wave focal lengths; Based on the above first,
An ultrasonic water thermometer comprising an arithmetic circuit that calculates the water temperature at a depth near the middle of the second acoustic wave focal length. 2 In the first and second transducers, a plurality of transducers are arranged in a line, and a delay phase amount is set for each transducer so that the directivity directions set by each adjacent transducer all intersect at one point. The ultrasonic water temperature according to claim 1, characterized in that the transmitter/receiver is configured such that the first and second acoustic wave focal lengths are obtained by varying the delay phase amount. Total.