JPS60131436A - Measuring device of water temperature - Google Patents

Abstract

PURPOSE:To measure water temperature speedily over a wide range with an ultrasonic wave by utilizing the fixed relation among the propagation speed of the ultrasonic wave, refraction in water, and water temperature. CONSTITUTION:The 1st ultrasonic wave transmitter and receiver 1 sends an ultrasonic wave S1 downward vertically and receives a reflected wave from the bottom of water in the direction to detect the echo time, and the 2nd ultrasonic wave transmitter and receiver 2 sends an ultrasonic wave S2 slantingly at a specific angle to a horizontal plane and receives a reflected wave from the bottom of water in the direction to detect the echo time. Further, the surface layer temperature on the water surface is measured by a temperature detecting element 3. Said echo time data and surface layer temperature are inputted to an arithmetic circuit 4, which utilizes the specific correlation among the underwater propagation speed of the ultrasonic waves, refractive index, and water temperature to calculate the water temperature near the bottom of the water, which is displayed on a display device 5.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an underwater water temperature measuring device, and more particularly to a device that indirectly measures the water temperature near the bottom of the water by utilizing the relationship between the propagation velocity and refraction of ultrasonic waves in the water and the water temperature.

When measuring the water temperature in the sea, especially near the seabed, for ocean measurement and exploration of fishery resources, conventional methods have involved lowering a thermometer to the desired depth and directly measuring the seawater source. However, such means have the disadvantage that they can only measure the temperature in the vicinity of the temperature measuring element, and that it is difficult to quickly know the distribution or change of temperature over a wide range.

In view of the above drawbacks, this invention focuses on the fact that there is a certain relationship between the propagation speed and refraction of ultrasonic waves in water and water temperature, and uses ultrasonic waves to quickly and The purpose of this invention is to provide an underwater water temperature measuring device that can measure water temperature over a wide range.

This invention emits ultrasonic waves vertically downward from the horizontal plane,
A first ultrasonic transducer receives waves reflected from the bottom in this direction, and a second ultrasonic transducer emits ultrasonic waves in a direction inclined at a certain angle with respect to the horizontal plane and receives waves reflected from the bottom in this direction. The reverberation time obtained from the transducer, the temperature measuring element that measures the surface temperature of the water surface, the first and second ultrasonic transducers, and the temperature information from the temperature measuring element are input, and from these the temperature information is input into the water. It is characterized by being comprised of an arithmetic circuit that calculates the water temperature near the water bottom based on a certain correlation between the propagation velocity and refractive index of the ultrasonic wave and the water temperature, and a display device that displays the calculated water temperature value. .

This invention will be explained below with reference to Examples.

FIG. 1 is a detailed explanatory diagram of the present invention, and FIG. 2 is an explanatory diagram of the operation of the embodiment.

□1 The underwater water temperature measuring device A of the present invention is installed on the bottom of a ship V, and emits ultrasonic waves S1 vertically downward with respect to the horizontal plane W.
a first ultrasonic transducer 1 that emits and receives sound waves reflected from the water bottom in this direction; and a first ultrasonic transducer 1 that emits ultrasonic waves S2 in a direction inclined at a constant angle θ1 (for example, θ1-45°) with respect to the water surface W. , a second ultrasonic transducer 2 that receives bottom-reflected sound waves in this direction, a temperature measuring element 3 that measures the surface temperature of the water surface W, and the first and second transducers 1.2. The reverberation times t1 and tz of the respective ultrasonic waves sl and s2 and the temperature information TCC) from the temperature measuring element are manually input, and from these, the propagation velocity of the ultrasonic waves in water is 01.02, and a constant relationship between the refractive index and the water temperature is calculated. It is comprised of an arithmetic circuit 4 that calculates the water temperature near the water bottom W] 3 from a correlation, and a display device 5, for example, a digital display device, that displays the water temperature value calculated by the arithmetic circuit 4.

In the above embodiment, the first and second ultrasonic transducers 1
．． In order to improve measurement accuracy, both of 2 are preferably directional, and for example, the transmitters of ultrasonic transducers 1 and 2 use pencil beam transducers. .

Further, a thermistor or the like is used as the temperature measuring element.

Next, the operation of this invention will be explained.

First, when the first and second transducers 1.2 are activated,
Reverberation time t1 of the ultrasonic wave from the water bottom WB in each case
．． tz (seconds) is input to the arithmetic circuit 4, and at the same time, the surface water temperature T (:C) is also input.

The calculation process in the calculation circuit 4 is performed using the following logic.

That is, in general, the underwater propagation speed of sound waves changes depending on salinity and pressure, but when the water depth is shallower than 200 to 300 m, the amount is small and can be ignored. Therefore, the speed of sound C (m/s) at the depth H (m) underwater is equal to the water temperature T
CC), then from the empirical formula 0=1449.22+4
．． 6233T-5, a5sbx162ze+'1.605
'i8X'lδ vehicle, it can be expressed as a function of water temperature F (T>).

By the way, changes in water temperature in water are usually extremely complicated, and the function described in "2" becomes even more complicated if water depth is considered as a variable. However, to simplify the explanation, the water temperature in water T0 is shown in Figure 2. The water temperature in the upper layer is T1'rQs, the water temperature in the lower layer is T2[(E), and the underwater sound speed at water temperatures T1 and T2 is 01(m/'1). .

02 (m/s), the relationship with the reverberation time t1 of the first ultrasonic transducer 1 is as follows, and the relationship with the reverberation time t2 of the second ultrasonic transducer 2 is as follows. ......■ (However, 02□ indicates the refraction angle of the ultrasonic wave S2 in the ice temperature change layer t).

On the other hand, the refraction angle θ of the ultrasonic wave in the water-induced change layer.

There is a relationship between θ and the sound speeds a1 and 'c2 based on Snell's formula.

□ In the above □ formulas ■, ■, and ■, tl and tz are known from the first and second ultrasonic wave transmitters 1 and 2, and C1 is also known and can be calculated from the temperature Tte near the water surface. Treat it as
Furthermore, θ1 is the angle of the second ultrasonic transducer 2 and can be treated as a constant, so the unknowns are C2, θ2 +'
The number of H is three, which matches the number of equations, so the above equation can be solved as simultaneous equations.

For example, if you solve for C2, From type 0 Substitute ■°, ■゛ into the 0 formula, Therefore, I will make a hail.

If C2 is calculated by solving this, the water temperature T20 at the water depth (H/2~H) is F (T2) -02-1449,,22-4,623
3T2+5.4585 X l02T2 and 1. F(
By solving T2)=O, the water temperature T(O) at the bottom of the water can be found.There are two solutions for F(T2), but if you solve it using the bisection method, you can reduce the range of solutions to a realistic one, for example, O"0~ It can be limited to 50°C, etc.

The above theoretical formula is for a simplified two-layer model, and in reality, the propagation path of the sound wave becomes non-linear due to the complex distribution of water temperature as shown in FIG. Therefore, the value obtained using the above theoretical formula is a relative value to the average water temperature near the water surface near the water surface. Various correction values are obtained by comparison with the stored water temperature, and based on these, various corrections are made in the arithmetic circuit 4, and finally the bottom water temperature T2TC1 is displayed on the display.

Since this invention is configured as described above, by simply setting the depression angle and directivity of two types of ultrasonic transducers and measuring the surface water temperature, the bottom water temperature in the water area can be measured. It is also possible to measure water temperature continuously from a moving ship, making it possible to easily measure bottom water temperatures over a wide range of areas in a short period of time.

[Brief explanation of drawings]

FIG. 1 is a detailed explanatory diagram of the present invention, and FIG. 2 is an explanatory diagram of the operation of the embodiment. A... Underwater water temperature measuring device, V... Ship, W...
Horizontal plane, Sj, s2... Ultrasonic wave, 1... First ultrasonic transducer, 2... Second ultrasonic transducer, 3.
...Thermometer element, 4... Arithmetic circuit, 5... Display device.

Claims (1)

[Claims] (1) A first ultrasonic transducer that emits ultrasonic waves perpendicularly downward to the horizontal plane and receives reflected waves from the bottom in this direction, and a first ultrasonic transducer that emits ultrasonic waves in a direction inclined at a certain angle to the horizontal plane. a second ultrasonic transducer that receives waves reflected from the water bottom in this direction; a thermometer that measures the surface temperature of the water surface; and respective echoes obtained from the first and second ultrasonic transducers. The time and temperature information from the thermometer are manually input, and a calculation circuit that calculates the water temperature near the water bottom based on a certain correlation between the propagation velocity of ultrasonic waves in the water, the refractive index, and the water temperature, and the calculated water temperature value are displayed. 1. An underwater water temperature measuring device comprising: a display device for measuring water temperature;