JPH0382952A - Measuring method and apparatus of sound velocity and viscosity of liquid by surface wave - Google Patents

Abstract

PURPOSE:To measure the sound velocity and viscosity of a liquid with high accuracy by operating the supersonic speed and viscosity of said liquid according to a plurality of specific formulae based on the variance obtained when the distance between a sensor and a reflecting plate is changed. CONSTITUTION:The supersonic speed Va is obtained according to an equation I (Vs: speed of the surface wave, DELTAt: delay time difference at the moving time, DELTAh: moving height) on the basis of a variance DELTA obtained by changing the distance between a sensor 2 and a reflecting plate 3. Thereafter, a bulk modulus kappaof the liquid is operated according to an equation Va=(kappa/rho)<1/2> on the basis of the supersonic speed Va. Then, after measuring a transmission loss alpha of the surface wave per a unit length, the viscosity eta of the liquid is operated by the use of the bulk modulus kappa according to an equation II (P: power flow per a unit width without perturbation, rho: density of a liquid, V1<2> (i=1, 2, 3): particle speed component at the surface, Vs: transmission speed of the surface wave). Accordingly, the sound velocity and viscosity of the liquid can be measured.

Description

DETAILED DESCRIPTION OF THE INVENTION C. Field of Industrial Application The present invention relates to a method and apparatus for measuring the sound velocity and viscosity of a liquid using surface waves.

[Prior art] Methods for measuring acoustic properties such as sound velocity and viscosity of liquids are as follows:
It has been studied for a long time and many things have been put into practical use.

Viscometers that have been put into practical use so far include capillary viscometers that use the flow of fluid in a capillary, rotational and vibrational viscometers that measure viscous resistance, and bubble viscometers that use rising bubbles and falling balls. There are falling body viscometers, etc.

In addition, the pulse method that measures the propagation time of ultrasonic pulses, the continuous wave method that uses continuous wave interference, and the optical measurement method that uses light are used to measure the sound velocity of liquids.

These methods for measuring the sound velocity and viscosity of liquids are applied to various liquid manufacturing apparatuses, and are used to stabilize, improve, and inspect liquid quality.

Furthermore, recently, a method of performing the above measurement using surface waves has been proposed. This surface wave is transmitted through a transducer (I D T
; Inter Digital Transdus
er) is known to be excited. Such a surface wave has three displacement components: a component tJ in the traveling direction, a component U2 parallel to the surface and perpendicular to the traveling direction, and a component U3 in the depth direction of the substrate.

Up until now, only piezoelectric substrates on which SH mode surface waves with very small U3 components propagate have been used as surface wave substrates used for such purposes. Surface waves in the SH mode, which have very small U and components, propagate without radiating their energy even when placed in a liquid. However, if the liquid has viscosity, this wave will combine with the U, , U, components, causing a velocity delay or attenuation, so it can be used as a liquid viscometer. Then, the viscosity is determined by the general formula (1) derived from the perturbation theory below.

The above equation is the surface wave propagation loss α [db/
mml. However, P: power flow per unit width in non-perturbed state, ρ: density of liquid, η: viscosity of liquid, V
i (i = 1, 2.3): particle velocity component at the surface, ■l
is the propagation velocity of the surface wave, and is the bulk modulus of the liquid.

The first term on the right side of the above equation represents attenuation due to energy radiation due to viscosity into the liquid, and the second term represents attenuation due to ultrasonic radiation. According to this equation (1), the viscosity of the liquid can be determined by using the surface waves in the SH mode.

[Problems to be Solved by the Invention] However, these methods only measure either viscosity or sound velocity, and cannot measure both at the same time.

In addition, the liquid to be measured was extracted as a large amount of sample, which required time and effort to perform measurements, and it was not possible to perform real-time measurements during the liquid manufacturing stage. .

In addition, those that measure viscosity using surface waves only use piezoelectric substrates with very small U components;
The second term on the right side of the above formula (11) was omitted and was determined by an approximate formula.

This is because it was assumed that the U3 component was very small, but it had a problem that caused an error.

In addition, methods for effectively utilizing the U3 component and specific EDT
This was due to the fact that the structure was not presented.

The present invention has been made in view of the above problems, and includes:
The first object of the present invention is to provide a method for measuring the sound velocity and viscosity of a liquid using surface waves, which can measure the sound velocity and viscosity of a liquid with high precision.

In addition, it is possible to simultaneously measure the sound velocity and viscosity of a liquid in real time, and this measurement can be performed with only a small amount of liquid, improving work efficiency. The second purpose is to provide a liquid sound velocity/viscosity measuring device using the present invention.

[Means for Solving the Problems] In order to achieve the above object, the method for measuring the sound velocity and viscosity of a liquid using surface waves of the present invention uses surface waves and ultrasonic waves provided in the liquid 1 as an object to be measured. - A method for measuring the sound velocity and viscosity of a liquid using surface waves, which uses a sensor 2 that receives waves and a reflector 3 to measure the sound velocity and viscosity of a liquid based on the propagation characteristics of surface waves and ultrasonic waves in the liquid, the method comprising: Based on the amount of change Δ obtained by moving the ultrasonic waves emitted from the sensor, the ultrasonic velocity Va is determined.Vg: velocity of surface wave, Δt: delay time difference obtained during movement, Δh: amount of movement.

After determining the ultrasonic velocity Va, calculate the bulk elastic modulus of the liquid as Va - "77T using the following formula. After this, after measuring the propagation loss α of the surface wave per unit length, The viscosity of the liquid is determined by the following formula using the bulk modulus, η. However, P: Power flow per unit width when no perturbation ρ: Density of the liquid, Vi (i=1.2.3): Particle velocity at the surface Component, V8: Propagation speed of surface wave.

The bulk modulus κ is then measured.

Further, the sound velocity and viscosity measurement device for liquid using surface waves according to claim 2 is provided in a piezoelectric substrate 2a that is provided in a liquid I as an object to be measured and is formed of a material having a large radiation component in the depth direction of the substrate. , wave transmitting electrodes 2c and 2g that are provided on the piezoelectric substrate and emit into the liquid, wave receiving electrodes 2d, 2e, 2f, 2h, and 2i that receive the waves, and a wave transmitting electrode 2 that is empty. a reflecting plate 3 provided in the liquid to reflect the ultrasonic waves emitted from the sensor; a Z-axis moving means 6 for moving the ultrasonic waves emitted from the sensor; and a Z-axis moving means 6 for moving the ultrasonic waves emitted from the sensor; Calculating the sound speed Va from the difference in the detection signal t of the liquid detected by the sensor,
The present invention is characterized by comprising an analysis device 5 which calculates the bulk modulus of the liquid from this result and calculates the viscosity η using the bulk modulus of the liquid.

[Function] According to the method according to claim 1, the ultrasonic velocity Va of the liquid 1
can be easily determined based on the amount of change Δ(Δh, Δt) obtained by moving the ultrasonic waves emitted from the sensor.

Next, the bulk modulus K of the liquid is determined by the ultrasonic velocity Va, and then the viscosity of the liquid is determined using this bulk modulus K of the liquid, so the viscosity of the liquid can be measured with high precision. .

According to the device according to claim 2, since the sensor 2 uses the piezoelectric substrate 2a which has a large U component with respect to the liquid, the detection signal t when the sensor 2 moves is large and the amount of change thereof is large. Large and accurate measurements can be made.

Furthermore, the sensor 2 itself can be miniaturized and measurement can be performed using a small amount of liquid 1.

Further, the sensor 2 can be moved with high accuracy because the distance between it and the reflecting plate 3 is accurately moved by the Z-axis moving means 6.

In addition, the analysis device 5 only obtains the amount of change Δ when the sensor 2 is moved by the Z-axis moving means 6, and calculates the sound velocity Va of the liquid 1 and the bulk elastic modulus of the liquid 1 based on this sound velocity Va.
A series of arithmetic operations can be automatically performed to obtain the viscosity η of a liquid with a bulk modulus K of .

Therefore, according to the above-mentioned device, only one sensor 2 is used, and immediately after this sensor moves in the liquid
The sound velocity Va and the viscosity η can be determined simultaneously.

[Example] FIG. 1 is a schematic diagram showing a first example of a liquid sound velocity/viscosity measuring device using surface waves of the present invention.

Reference numeral 1 denotes a liquid as an object to be measured, and a sensor 2 is provided in the liquid 1 at a predetermined distance from a reflecting plate 3. The reflecting plate 3 is made of a reflective material such as glass.

As shown in the perspective view of FIG. 2, the sensor 2 is called a TDT, and has comb-shaped interdigital electrodes 2c and 2d formed on a piezoelectric substrate 2a with a pattern spaced apart from them. It is. That is, surface wave delay line (SA W dela
y Hne ).

1 One of these interdigital electrodes 2C12d is a transmitting electrode for ultrasonic emission and surface wave excitation, and the other 2d is a receiving electrode for receiving waves. 2C is connected to the input device 4, and the wave receiving electrode 2d is connected to the analysis device 5.

The human power device 4 includes a high frequency oscillator 4a and a clock oscillator 4b.
, and a mixer 4c consisting of a gate circuit or the like which outputs a high frequency wave at a clock cycle by mixing these.

The analysis device 5 includes a processing device 5a that measures the speed of sound and viscosity in a liquid by performing operations to be described later, and a display section 5b that displays the measured values.

Note that the analysis device 5 may be configured to perform waveform observation using a synchroscope.

Further, the Z-axis moving means 6 is constituted by, for example, a Z-axis stage and moves the sensor 2 in the Z-axis direction (Δh described later), and the sensor 2 is fixed to the Z-axis moving means 6 via an arm 6a. Ru. This Z-axis moving means 6 is connected to the processing device 5.
The operation is controlled by a control signal 2 from a.

Here, the principle of measurement by this sensor 2 will be explained.

Surface acoustic waves are excited using the piezoelectric substrate 2a and the wave transmitting electrode 2c.

The piezoelectric substrate 2a of the present invention is made of lithium niobate ft1ri.
Among the surface waves propagating on the surface of bo3), lithium tantalate (LiTaO5), etc., a wave close to the Sol mode in which U3, U, and U2 both exist is used.

The surface waves (indicated by arrows in FIG. 1) on the surface of the piezoelectric substrate 2 made of LiNbO3, LiTaO5, crystal, etc., which have been cut in a specific manner, have displacement components of U, U, U3. For example, when changing the Lt of Y cut and the cut plane of the surface wave propagating in the X direction of the NbO3 substrate, the components of each displacement are the third
As shown in the figure.

The present inventor has developed a sensor 2 having such a piezoelectric substrate 2a.
When we experimented by putting it in liquid 1, we discovered the following characteristics.

l) The surface wave combines with the liquid l ultrasonic wave by the U3 component, radiates energy into the liquid l, and is attenuated.

2) If the liquid l has viscosity, it will combine with the U2 component and the surface waves will be attenuated.

The magnitude of the viscosity can be obtained by measuring the attenuation characteristic due to this U2 component, and the sound velocity can be obtained by measuring the propagation characteristic of the ultrasonic wave radiated into the liquid l.

Therefore, in the device having the configuration shown in FIG. 1, the surface wave excited from the transmitting electrode 2C propagates while emitting part of its energy as an ultrasonic wave through Moto conversion. It is detected by the electrode 2d. Also,
The emitted ultrasonic wave is reflected by a reflection plate 3 placed parallel to the piezoelectric substrate 2a, enters the piezoelectric substrate 2a again, is converted into a surface wave, and is received by the wave receiving electrode 2d. Therefore, two signals (high frequency pulses) with different delay times are received by the receiving electrode 2d and appear as electrical signals.

The measurements described later can be performed using this reception characteristic.

FIG. 4 is a block diagram showing the internal configuration of the processing device 5. As shown in FIG.

The Z-direction movement amount setting means 51 sets the movement amount Δh of the Z-axis movement means 6 in the Z-axis direction (height direction), and outputs a movement operation signal a of the Z-axis movement means 6 during the operation described below. .

The data input means 52 receives the detection signal t (Tl, tl, t2) from the receiving electrode 2d, and outputs it to the subsequent stage after A/D conversion. The maximum value of these detection signals t is supplied to the subsequent stage by a sample hold circuit and a peak value extraction circuit (not shown) for digital processing at the subsequent stage. Further, this detection signal Tl is transmitted to the wave transmitting/receiving electrode 2c.

The delay time of a surface wave generated between 2d and tl.

t2 is a delay time of a wave mode-converted to an ultrasonic wave.

The data storage means 53 temporarily stores and holds the detection signal tl before moving the Z-axis moving means 6. Z for this
A detection signal t2 when the axis moving means 6 is moved by Δh is also stored.

5 Δ directly above means 54 calculates Δ to 2 t 1 based on the detection signals tl and t2. − Calculate the delay time difference Δt using t 2 . Incidentally, the detection signal t2 is obtained when the Z-axis moving means 6 moves during the operation described later.

The sonic velocity calculation means 56 calculates the ultrasonic velocity (hereinafter abbreviated as sonic velocity) Va in the liquid based on the data stored in the parameter storage means 55 using the following equation (2), and outputs it to the data output means 59.

(2) Here, ■8 is the speed of the surface wave propagating on the surface of the piezoelectric substrate 2a in the liquid l, and is determined from the distance between the transmitting electrode 2C and the receiving electrode 2d at the time of manufacturing the sensor 2. Vs=L/Tl
This is a fixed value that can be easily obtained from the relationship (L: propagation distance, T1: delay time of surface wave). Although this fixed value varies depending on the type and properties of the liquid, it can always be determined for each case from T1. This ■6 is the parameter storage means 55
is stored in

This formula (2) is unique to the present inventor, and this new means (formula (2) and movement control in the Z direction) makes it possible to use this new method (formula (2) and movement control in the Z direction), which has not been strictly considered when calculating the speed of sound. The speed of sound can be determined accurately without depending on the radiation angle θ of the sensor 2, which did not occur.

The bulk modulus calculating means 57 calculates the bulk elastic modulus of the liquid from the following equation (3) based on the calculated values V and a of the sound velocity calculating means 56.

Va=r (3) The viscosity calculating means 58 calculates the viscosity n of the liquid from the calculated value of the bulk modulus calculating means 57 using the above formula (1), and outputs it to the data outputting means 59.

The data output means 59 outputs the analog measurement waveform, sound velocity, viscosity data, etc. to the display section 5b via the A/D.

Next, the operation of the above configuration will be explained using the flowchart of FIG.

First, the sensor 2 having the above configuration is provided in the liquid 1, and the data input means 52 detects the delay characteristic t of the liquid 1 using the detection signal t.
Measure as SI) 1. ) and stored in the pig storage means 53.

Next, measure the surface wave propagation loss α per unit length (SF3).

Next, the Z-direction movement amount setting means 51 sets the Z-axis movement means 6.
is moved in the force direction by Δh (SF3). As a result, the sensor 2 is moved in the direction of the U3 component, and the delay characteristic changes.

Here, since the movement of the sensor 2 can be controlled with high precision by the Z-axis moving means 6, the delay characteristic can be measured with high precision.

Next, the sensor 2 measures the detection signal t2 (SF3
).

Then, the calculation means 54 calculates Δ as the detection signal t2 and
The difference Δ from the detection signal ti stored in the data storage means 53
Calculate t (delay time difference) (SF3).

Next, the sonic velocity calculation means 56 calculates the sonic velocity Va of the liquid l using the above equation (2) (S l?5). Among the necessary parameters, △t uses the calculation output value of the calculation means for Δ, Δh uses the value of the Z-direction movement amount minus setting means 51, and ■ is stored in the parameter storage means 55. Use the value.

The sonic velocity Va of the liquid determined by the sonic velocity calculating means 56 is sent to the data outputting means 59.

Based on the sound velocity Va obtained here, the bulk elastic modulus calculating means 57 calculates the bulk elastic modulus of the liquid 1 using the above equation (3) (SF3).

Next, the viscosity calculation means 58 calculates the viscosity η of the liquid l using the above equation [11] (SF3).

Since the propagation loss α of the surface wave per unit length and the bulk modulus K of the liquid have already been obtained, the equation (1
), the loss due to the U3 component of the second term on the right side can be accurately determined, and the viscosity η can be determined with high precision. This viscosity n is sent to the data output means 59.

The data output means 59 outputs a measured waveform of the detection signal t;
The sound velocity Va sent out from the sound speed calculation means 56 and the viscosity η sent out from the viscosity calculation means 58 are outputted to the display section 5b.

Next, FIGS. 6(a) and 6(b) are diagrams showing a specific installation example of this device.

FIG. 6(a) is a front sectional view of a storage tank 60 that constitutes a part of the liquid 1 manufacturing apparatus, and is an example in which the sensor 2 is installed in this storage tank 60.

In the figure, reference numeral 61 has a reflector 3 on the bottom, a Z-axis moving means 6 on the top, and an opening 6 on the side for inflowing the liquid.
This is a storage case in which 2 is provided.

Further, the sensor 2 is fixed to the lower part of the Z-axis moving means 6.

FIG. 6(b) is a plan cross-sectional view of the delivery pipe 71 in the process of manufacturing the liquid 1. A branch path 72 is provided at an intermediate position, and the sensor 2 and the reflector plate 3 are provided in this branch path 72 portion. It is something that The sensor 2 is a Z-axis moving means 6 (not shown)
It is freely movable in the vertical direction.

In these specific configurations, the main parts (Figure 1)
Since the sensor 2 portion is formed to be approximately 1 cm2, the amount of liquid required for detection by this sensor 2 is approximately 2 to 3 cm3.
The sensor 2 and the peripheral devices of the sensor 2 can be miniaturized, and can be easily installed in a liquid manufacturing apparatus.

In the above-described embodiment, the movement in the Z-axis direction was performed on the sensor 2 side, but it is also possible to configure the reflection plate 3 to move in the Z-axis direction and to fix the sensor 2. Even in this case, the same effects as those of the above-mentioned embodiment can be obtained.

Next, FIG. 7(a) is a perspective view showing a second embodiment of the present invention.

This embodiment differs from the first embodiment in the sensor, and the other components are the same as in the first embodiment, and their explanations will be omitted.

This sensor 22 has a piezoelectric substrate 2a similar to that of the previous embodiment.
Use. A transmitting electrode 2 is provided at the center of the piezoelectric substrate 2a.
Provide c. Further, two receiving electrodes 2e and 2f are provided on the left and right sides of the transmitting electrode 2c, respectively. The receiving electrode 2e is provided at a distance L1 from the transmitting electrode 2c, and the receiving electrode 2f is provided at a distance L2 from the transmitting electrode 2c (LL<L2).
.

By using such a sensor 22, the propagation loss α(
a=α2−αl) can be easily obtained.

Next, FIG. 7(b) is a perspective view showing a second embodiment of the present invention.

This embodiment is a modification of the second embodiment.

This sensor 23 has a piezoelectric substrate 2a similar to that of the previous embodiment.
Use. A wave transmitting electrode 2g is provided at the end of this piezoelectric substrate 2a. Furthermore, there are two receiving electrodes 2 at the center and at the other end.
h and 2i are provided respectively. The receiving electrode 2e is provided at a distance LL from the transmitting electrode 2c, and the receiving electrode 21 is provided at a distance L2 from the transmitting electrode 2c.

By using such a sensor 23, the propagation loss α can be easily obtained as in the above embodiment, and
Since both the receiving electrodes 2h and 2i are arranged in the same direction when viewed from the transmitting electrode 2g, the ultrasonic waves of the U and component components radiated in the same direction are each received and propagated. This makes it possible to improve the measurement accuracy of loss α.

As a specific application example of the present invention, in addition to the above-mentioned various liquid manufacturing devices, it can be used as a monitor of proteins in blood, etc. Even in this case, since only a small amount of sample is required, the present invention can be used. The effect can be used effectively.

(Actual measurement example) Next, an actual measurement example using the above embodiment will be shown l) Regarding the toilet sensor Sensor used: sensor 22 in Fig. 7(a) Material of substrate 2a of sensor 22: 36°Y X L I N bOs.

3 Ll; 5mm.

L2+10mm.

Frequency of high frequency oscillator 4a: 30M! (z　.

Liquid: Glycerin aqueous solution.

Liquid amount: 4-5 cc.

2) Measurement of sound velocity Procedure for determining the sound velocity Va using equation (2) above (Fig. 8(a)
) is the input waveform input to the wave transmitting electrode 2c, and FIG. figure(
c) is the waveform of the same wave receiving electrode after being moved in the Z direction. ) 1) Obtain tl from the waveform before the Z-axis moving means 6 moves. This tl is obtained based on the input wave and the leading shoulder position portion of the underwater propagation wave response 1.

2) Obtain t2 from the input wave and the underwater propagation wave response 2 after moving by Δh (moving the distance between the sensor 2 and the reflecting plate 3 closer by 1 mm compared to before the movement) using the Z-axis moving means 6.

4 3) Obtain TI from the input wave and surface wave response (before and after movement, either is fine).

4) Find V, (surface wave velocity) from TI and L (distance between transmitting and receiving electrodes). (V, =L/TI)5)Δt=
Find tl-t2.

6) Find the speed of sound from Δt, Vs, and Δh using equation (2) above.

*Measurement results (note: difference is within 2%) Here, the sound speed of water (nominal value) is 150 at 23° to 27°.
0 m/s, the measuring method of the present invention was able to obtain measurement accuracy equivalent to that of the conventional method, and was also able to perform measurement more easily than the conventional method.

Incidentally, FIG. 9 shows the sound velocity measurement results according to the conventional method and the present invention.

3) Measurement of surface wave propagation loss α, which is a prerequisite for obtaining liquid viscosity 1) Regarding the nominal values of water and glycerin aqueous solution 2) 36
"YX LiNb0. Particle velocity component normalized to the power of the substrate V + / JP = 0.171 X 10-"x
J ωV 2/ f P = 0.304 x 10-
'x JωV 3 /f P = 0.107 X 1
0-'X Jω3) Comparison of measured value and calculated value
It shows. The calculated values used were those shown in 1) and 2) above.

In this way, the measured values were obtained that were close to the calculated values with high precision.

As a result, the viscosity of the liquid is 1, (
lυ5cp (glycerin solution υ%)...Reference value 6,
7 (I cp (glycerin solution 50%). Thus, the viscosity of the 50% solution shows a relatively good value at the nominal value of 6.05 cp.

FIG. 10 shows the characteristic of viscosity change versus propagation loss α, and according to the method of the present invention, the value was very close to the perturbation solution, and the viscosity could be measured accurately.

[Effect of the Invention J] According to the method for measuring liquid sound velocity and viscosity using surface waves according to claim 1, the sound velocity and viscosity of a liquid can be measured with high accuracy.

According to the liquid sound velocity/viscosity measurement device using surface waves according to claim 2, the sound velocity and viscosity of the liquid can be measured simultaneously with one sensor.
Moreover, it has the effect of being able to be measured in real time.

Furthermore, since this sensor can be miniaturized, it does not take up much space at the location where it is applied, and only a supplementary amount of liquid is required for measurement.

[Brief explanation of drawings]

7. Fig. 1 is a schematic diagram showing a first embodiment of the liquid sound velocity/viscosity measuring device using surface waves of the present invention, Fig. 2 is a perspective view showing a sensor of the device, and Fig. 3 is a piezoelectric substrate. Y c used for
A graph showing the components of each displacement when changing the cut plane of the surface wave propagating in the X direction of the LiNbO5 substrate of the U.T., FIG. 4 is a block diagram of the inside of the processing device of the same device, and FIG. A flowchart showing the operation of the above-mentioned apparatus, which is a liquid sound velocity/viscosity measurement method using surface waves, FIGS. 6(a) and 6(b)
) are a side sectional view and a plan sectional view showing a specific example of application of the device, FIG. 7(a) is a perspective view of a sensor showing a second embodiment of the device, and FIG. 7(b) is a perspective view of a sensor showing a second embodiment of the device. A perspective view of a sensor showing the third embodiment of the device, FIG. 8 is a diagram showing input and output waveforms before and after moving the reflector, FIG. 9 is a sound velocity measurement value according to the conventional method and the present invention, and FIG. , is a characteristic table of viscosity change-propagation loss α. i...liquid, 2,22.23--sensor, 2 a...
= Piezoelectric substrate, 2C, 2g-... Transmission electrode, 2d, 2e
. 2f, 2h, 2i... Receiving electrode, 3... Reflector, 4
... 8 input device, 4a... high frequency oscillator, 41]... clock oscillator, 4c... mixer, 5... analysis device, 5
a... Processing device, 5b... Display section, 6... Z-axis moving means, 6a... Arm, 51... Z-direction movement wind setting means, 52... Data input means, 53. . . . Data storage means, 54 . . . Δ7 calculation means, 55 . . . Parameter storage means, 56 .・・・
- Data output means, 60... storage tank, 61... storage casing, 62... opening, 71...- delivery pipe, 72...
Branch road.

Claims (1)

[Claims] 1. A sensor (2) for transmitting and receiving surface waves and a reflector (3) provided in a liquid (1) as an object to be measured.
A method for measuring the sound speed and viscosity of a liquid using a surface wave, which measures the sound speed and viscosity of a liquid based on the propagation characteristics of surface waves in the liquid, the method comprising: changing the sound speed and viscosity of a liquid by changing the distance between the sensor and the reflecting plate; Based on the quantity Δ, the ultrasonic velocity Va Va=√{4V_s^2(Δh)^2}/{V_s^2
(Δt)^2+4(Δh)^2} [m/s] However, V_
s: speed of surface wave, Δt: delay time difference obtained during movement, Δh: amount of movement. After determining the ultrasonic velocity Va, calculate the bulk elastic modulus of the liquid κ Va=√κ/ρ using the following formula, and then measure the surface wave propagation loss α per unit length. After determining the bulk elasticity modulus κ, the liquid viscosity η α=20logexp[1/4P{√ρωη/2(V_
1^2+V_2^2)+ρV_s√(κ/ρV_s^2
-κ)V_3^2}] where, P: power flow per unit width in unperturbed state, ρ: liquid density, Vi (i=1, 2, 3): particle velocity component at the surface, V_s: surface Wave propagation speed. A method for measuring the sound velocity and viscosity of a liquid using surface waves, which is characterized by measuring the sound velocity and viscosity of a liquid by calculating . 2. A piezoelectric substrate (2a) provided in a liquid (1) as an object to be measured and made of a material with a large radiation component in the depth direction of the substrate; Transmitting electrodes (2c, 2g) that emit ultrasonic waves;
Receiving electrodes (2d, 2e, 2f, 2h, 2
i); a reflecting plate (2) provided in the liquid and reflecting ultrasonic waves emitted from the sensor;
3); Z-axis moving means (6) for moving the distance between the sensor and the reflecting plate; and determining the sound velocity from the difference in the detection signal (t) of the liquid detected by the sensor by moving the Z-axis moving means. (Va), calculates the bulk modulus of elasticity (κ) of the liquid from this result, and calculates the viscosity (η) using the bulk modulus of the liquid; Liquid sound velocity and viscosity measurement device using surface waves.