JPH07248315A - Density measuring device - Google Patents

Abstract

PURPOSE:To provide a density measuring device with which any calibration falls into disuse, whereby it becomes simplified in the case where an automatic measurement of fluid density for hours, and simultaneously it is able to perform such a density measurement as high in reliability accurately and speedily. CONSTITUTION:This density measuring device consists of a coupler being in contact with a test specimen fluid 1 subject to density measurements and attached with an ultrasonic vibrator 3 and a temperature sensor 4, an ultrasonic generator 5 being connected to the ultrasonic vibrator 3 and the sensor 4, and a computing element 6 being connected to those of vibrator 3 and sensor 3, and in this constitution, the extent of density in the test specimen fluid 1 is operated and measured by the computing element 6 from a degree of ultrasonic reflected wave strength out of a boundary between the coupler 2 and the specimen fluid 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a density measuring device suitable for measuring the density of seawater and the density of liquid in a tank.

[0002]

2. Description of the Related Art Conventionally, as a density measuring device for measuring the density of seawater and the density of liquid in a tank, there is a vibration densitometer for guiding a sample fluid into a measuring cell and measuring the density from its vibration period. Requires calibration, and therefore, when performing automatic measurement for a long time, the number of moving parts becomes large and the device becomes complicated, and there is also a problem that measurement cannot be done without sampling and measurement under high pressure environment. There is also an inconvenience that the measurement time becomes long due to the sampling.

[0003]

SUMMARY OF THE INVENTION The present invention has been proposed in view of the above circumstances and does not require calibration, which simplifies the device when performing automatic measurement of fluid density for a long time. An object of the present invention is to provide a density measuring device capable of accurately and quickly performing highly reliable density measurement.

[0004]

Therefore, according to the present invention, a coupler, which is in contact with a test fluid whose density is to be measured, is provided with an ultrasonic oscillator and a temperature sensor, and is connected to the ultrasonic oscillator. Comprising an ultrasonic oscillator and an arithmetic unit connected to the ultrasonic oscillator and the temperature sensor, and calculating and measuring the density of the test fluid from the ultrasonic reflected wave intensity from the boundary between the coupler and the test fluid. Is characterized by.

[0005]

In the density measuring apparatus of the present invention, the ultrasonic wave intensity at the boundary between the coupler and the fluid under test is E _i , the reflected wave intensity is E _R , the density is ρ, the sound velocity is c, and the acoustic impedance of the coupler is [rho ₁ c _1, provided when試流body acoustic impedance and [rho ₂ c _2, these relationships E _R = (ρ ₂ c
It is expressed by ₂ −ρ ₁ c ₁ ) / (ρ ₁ c ₁ + ρ ₂ c ₂ ) · E _i , and ρ ₁ c ₁ has temperature characteristics, and the propagation length of the reflected wave also has temperature dependence. Therefore, it is possible to calculate and measure the density ρ _{2 of the} sample fluid by sending the ultrasonic reflected wave intensity and the sample fluid temperature from the ultrasonic oscillator and the temperature sensor to the calculator, and calculating with the above equation. .

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the density measuring device of the present invention will be described with reference to the drawings. FIG. 1 shows the device, FIG. 1A is a schematic diagram thereof, and FIG. FIG. 2 is an enlarged view of a portion, FIG. 2 is a diagram showing the relationship between temperature T and the coupler acoustic impedance ρ ₁ c _{1 in} the same device, and FIG. 3 is a diagram showing the relationship between temperature T and the test fluid propagation length l _{2 in} the same device. 4 is an explanatory diagram of an application example of the present apparatus to seawater density measurement, and FIG. 5 is an explanatory diagram of an application example of the present apparatus to fermentation liquid density measurement in an ethanol fermentation tank.

In FIG. 1, an ultrasonic transducer 3 and a temperature sensor 4 such as a thermocouple are attached to a coupler 2 which is in contact with a test fluid 1 such as seawater or a fermented liquid whose density is to be measured. An ultrasonic oscillator 5 is connected to the vibrator 3, and the ultrasonic vibrator 3 and the temperature sensor 4 are both connected to a calculator 6. In such a device, the ultrasonic wave emitted from the ultrasonic oscillator 5 propagates through the coupler 2 and at the boundary in contact with the test fluid 1, the coupler 2 and the test fluid 1
The intensity E _{R of the} reflected wave is represented by the following equation in accordance with the difference in acoustic impedance between the two. E _R = (ρ ₂ c ₂ −ρ ₁ c ₁ ) / (ρ ₁ c ₁ + ρ ₂ c ₂ ) · E _i where ρ: density, c: speed of sound, ρ ₁ c ₁ : acoustic impedance of coupler 2 ( Known), ρ ₂ c ₂ : acoustic impedance (unknown) of the fluid under test 1, E _i : incident wave intensity at the boundary. In this equation, if E _i is always constant, E _R is detected by the ultrasonic transducer 3 so that ρ ₂ c
You can decide ₂ . However, figure out the temperature characteristics of ρ ₁ c ₁ as shown in Fig. 2. Also, the sound velocity c ₂ of the test fluid 1 is as shown in FIG.
Reflected wave from end face I of coupler 2 shown in (B) and end face II
From the time interval Δt with the reflected wave from and the distance l ₂ between the end face I and the end face II, c ₂ = 2l ₂ / Δt. Incidentally distance l ₂ is c ₂ by because it has a temperature-dependent advance to understand the temperature dependence of l ₂ as shown in FIG. 3, employs a l ₂ corresponding to the temperature measured by the temperature sensor 4 The estimation accuracy of is improved. Then, the density ρ _{2 of the} sample fluid 1 can be automatically estimated by sending these measured values from the ultrasonic transducer 3 and the temperature sensor 4 to the calculator 6 and calculating them by the above equation.

Next, an example of application to seawater density measurement will be described with reference to FIG. 4. In FIG. 4A, a density measuring device 7 corresponding to part B in FIG. 1 is introduced into seawater 1'with a pressure sensor, The density from the shallow sea area to the deep sea area as shown in Fig. 4 (B) is obtained by measuring and calculating the ultrasonic reflected wave intensity and seawater temperature for each depth while changing the cable length. The profile can be acquired accurately and quickly. Further, an example of application to the measurement of the fermented liquid density in the ethanol fermentation tank will be described with reference to FIG. 5. In FIG. 5, the fermentation is performed by opening the valve 9 and operating the induction pump 11 to remove the suspension such as yeast by the filter 10. The liquid is introduced into the coupler 2, the ultrasonic reflected wave intensity and the fermentation liquid temperature are measured and calculated to perform the density measurement, thereby accurately and quickly acquiring the density, that is, the concentration of the ethanol fermentation liquid in the ethanol fermentation tank 8. can do.

Thus, according to such a density measuring apparatus, the coupler 2 in which the temperature dependence of the acoustic impedance is known and the ultrasonic wave propagates is brought into contact with the fluid under test 1, and the ultrasonic transducer 3 and the temperature attached to the fluid are tested. Since the fluid density is calculated and measured by measuring the ultrasonic reflected wave intensity and the fluid temperature from the sensor 4, the fluid in a high-pressure environment, which was difficult for the vibration densitometer, without a preliminary procedure such as calibration with a simple device. Accurately and quickly realize the density measurement of fluids, which contributes to the high accuracy and speed of long-term automatic measurement of fluid density, from laboratory-level physical property evaluations to actual equipment measurements and ocean surveys. it can.

[0010]

In summary, according to the present invention, a coupler which is in contact with a fluid to be measured for density and which is provided with an ultrasonic vibrator and a temperature sensor, and an ultrasonic oscillator connected to the ultrasonic vibrator are provided. And a calculator connected to the ultrasonic transducer and the temperature sensor, and calibrates by calculating and measuring the density of the test fluid from the ultrasonic reflected wave intensity from the boundary between the coupler and the test fluid. Is unnecessary, therefore the device becomes simple when performing automatic measurement of the fluid density for a long time, and a density measuring device that can perform highly reliable and accurate density measurement is obtained.
The present invention is extremely useful in industry.

[Brief description of drawings]

1A and 1B show an embodiment of a density measuring device of the present invention. FIG. 1A is a schematic diagram of the device, and FIG. 1B is B of FIG. 1A.
It is an enlarged view of a part.

FIG. 2 is a diagram showing a relationship between temperature T and coupler acoustic impedance ρ ₁ c _{1 in} the same apparatus.

FIG. 3 is a temperature T and a sample fluid propagation length l ₂ in the same apparatus.
It is a diagram of the relationship of.

FIG. 4 is an explanatory diagram of an example of application of this device to seawater density measurement.

FIG. 5 is an explanatory diagram of an application example of the present apparatus for measuring the density of a fermented liquid in an ethanol fermentation tank.

[Explanation of symbols]

 1 Test Fluid 2 Coupler 3 Ultrasonic Transducer 4 Temperature Sensor 5 Ultrasonic Oscillator 6 Computing Unit

Claims (1)

[Claims] 1. A coupler which is in contact with a sample fluid whose density is to be measured and which is provided with an ultrasonic oscillator and a temperature sensor, an ultrasonic oscillator connected to the ultrasonic oscillator, and the ultrasonic oscillator. And a calculator connected to the temperature sensor, which calculates and measures the density of the test fluid from the intensity of the ultrasonic wave reflected from the boundary between the coupler and the test fluid.