JPH0328740A - Method for measuring viscosity of liquid and vibration type viscometer - Google Patents

Abstract

PURPOSE:To measure the viscosity of even low-viscosity liquid with high accuracy by transmitting vibration from an exciting means to an elastic body through an interme diate elastic body which has a smaller spring constant than the elastic body. CONSTITUTION:A spring supporting body 9 is provided on the lower end of a 1st upper vibration lever 4c fixed to a leaf spring 7, the external edge part of an intermedi ate leaf spring 10 is fixed to its external projection edge part 9a, and a 2nd upper vibration lever 4d is fixed in the center of reverse surface of the spring 10. The spring 10 is, for example, discoid and long punch holes 10a which are longer and longer as they are farther and farther from the center, shift in position alternately, and are bent while projecting it out side are formed concentrically. Consequently, the relation between the physical quantity rho.mu (rho: density, mu: viscosity) of the liquid 1 to be measured and the amplitude of the vibration of a vibrator 3 has superior linearly within a certain viscosity range. Further, the spring constant of the spring 7 is set to >=8 times as large as that of the spring 10. The spring constant of the spring 10 can be varied by varying the leaf spring thickness, so a measurement is taken over a wide range from high viscosity to low viscosity.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention particularly relates to a fluid viscosity measuring method and vibratory viscometer that utilize vibration to measure dryness of a fluid to be measured.

[Prior Art] Generally, in a vibratory viscometer, a vibrator installed at the lower end of a vibrating rod is immersed in the fluid to be measured, and a high-temperature wave having a predetermined vibration amplitude in the resonance region of an excitation device is applied to the vibrator through the vibrating rod. Accurate sinusoidal vibration is applied to detect the amplitude of the vibrator, which is attenuated by the viscous resistance of the fluid to be measured, while the amplitude value of the detected vibration is attenuated by a fluid with standard viscous resistance, such as a standard liquid. The viscosity of the fluid to be measured is determined by comparing the amplitude value after vibration damping of the vibrator.

As an example of the above-mentioned type of vibratory viscometer, there is one disclosed in Japanese Unexamined Patent Publication No. 51-15837, and this example will be described below with reference to FIG. 7 which shows its schematic configuration. will be introduced to.

That is, the reference numeral (1) shown in the figure is a high temperature fluid to be measured contained in a container (2);
) is immersed in a vibrator (3) provided at the lower end of a vibrating rod (4). The vibrating rod (4) is a lower vibrating rod (4a
) and an upper vibrating rod (4b), which are straightly joined by a joint (5). This is done so that when the vibrator (3) is damaged, it can be easily replaced with another vibrator.

The upper side of this upper vibrating rod (4b) is a storage case (
The guide member (8a) provided approximately at the vertical center of the
) is inserted into the guide hole (8b) of the coil spring 00), and the lower end of the coil spring 00) suspended from the lower side of the guide member (8a) is inserted into the collar-shaped spring receiver (9) provided on the upper vibrating rod (4b).
), this vibrating rod (4) is supported. Further, a brim-shaped reference plate (6) for displacement detection is provided on the protruding portion of the upper vibrating rod (4b) that protrudes upward from the guide member (8a), and this reference plate ( 6) At positions spaced apart from each other by a predetermined distance in the upper surface direction, zero eddy current displacement detection sensors for detecting displacement of the vibrating rod (4) are arranged. Furthermore, a disc-shaped vibration receiving plate (7) made of a permanent magnet or a ferromagnetic material is fixed to the upper end of the upper vibration rod (4b), and a predetermined position above the vibration receiving plate (7) is fixed to the upper end of the upper vibration rod (4b). Excitation coils 01) are arranged at spaced apart positions. The eddy current displacement detection sensor 02) is connected to the amplifier 03), and the excitation coil (II) is connected to the vibration control circuit 05) via lead wires, and these amplifiers 03) and the vibration control circuit 051 are all input to the arithmetic circuit Oa via lead wires.

Below, the effects of the vibrating type according to the viscosity described above will be explained. A predetermined power controlled by the six vibration control channels is supplied, and the vibrating coil (11) vibrates at a frequency in the resonance region. Due to this vibration, the vibration receiving plate (7) receives a sine wave vibration of a predetermined vibration amplitude.

The vibrations generated by the excitation are transmitted to the vibrator (3) through the vibrating rod (4). Next, the vibration of the vibrator (3) is damped by the viscous resistance of the fluid to be measured (1). Then, the damped amplitude of the vibration of the vibrator (3) is transmitted to the reference plate (6) through the vibrating rod (4),
Next, the amplitude of the vibration of the reference plate (6) is detected by an eddy current displacement detection sensor 02), and its output is input to an arithmetic circuit 04) via an amplifier 03).

On the other hand, the oscillator (3
) is vibrated in the air, and the amplitude value Ea of the vibration is input. Therefore, the amplitude value E of the measured vibration of the vibrator (3) in the fluid to be measured (1) manually applied from the human force value and the amplifier 03) by this calculation circuit 04) can be calculated using the following formula p ・u - K
(E/Ea-1)2 By substituting and calculating the density ρ and viscosity μ of the fluid to be measured.
The physical quantity ρ・μ, which is the product of

However, the English letter K shown in the above formula is a constant of the vibration system. What is obtained in this way is the physical quantity ρ・〃,
Of these physical quantities ρ and μ, the density ρ generally changes less depending on the measured fluid (1) than the viscosity μ, so changes in this physical quantity ρ and μ can be regarded as changes in the viscosity of the measured fluid (1). obtain.

However, as shown in 1984, No. 90 F Tetsu to Hagane, it is difficult to theoretically evaluate the resistance of mechanical impedance and the influence of vibrator slippage. Therefore, the values of the constants α and β are determined from the following equations ρ·μ−α (Ea/E−1)β.

[Problem to be solved by the invention]

Although the above-mentioned vibratory viscometer is useful to some extent, it still has the following problems from the viewpoint of viscosity measurement accuracy.

In other words, power is supplied to the excitation coil so that the vibration receiving plate vibrates at a frequency in the resonance region, but the impedance of the excitation coil changes in this region, and the vibration control circuit changes the supplied power. Even if controlled, this change in impedance causes a change in the power supplied to the excitation coil.

In other words, since the vibration amplitude of the vibration receiving plate changes, it is not possible to give the vibrator the high-accuracy sine wave vibration that is essential for this type of vibratory viscometer, and it is not always possible to measure the viscosity of the fluid being measured with high accuracy. The problem was that it was not possible.

In addition, in order to further reduce the influence of the impedance change mentioned above, it is not possible to use a coil spring with a small spring constant, so there is the problem that this cannot be applied especially when the fluid to be measured has a low viscosity. was occurring.

Therefore, an object of the present invention is to provide a fluid viscosity measuring method and a vibratory viscometer that can measure the viscosity of a fluid to be measured with high precision and can also be applied to measuring the viscosity of a low-viscosity fluid to be measured. .

[Means for Solving the Problems] The present invention has been made to solve the above-mentioned problems, and therefore, the gist of the method for measuring fluid viscosity according to the first aspect of the present invention is to A vibrator detachably fixed to the free end side of a vibrating rod supported by an elastic body excited by a means is immersed in the fluid to be measured, and the viscosity of the fluid to be measured is reduced by attenuating the amplitude of the vibration of the vibrator. In the viscosity measurement method of the fluid to be measured,
It is characterized in that the vibration from the vibration excitation means is transmitted to the elastic body through an intermediate elastic body having a spring constant smaller than that of the elastic body.

Further, the structure of the vibratory viscometer according to the second invention of the present invention,
A vibrator immersed in the fluid to be measured is provided at the free end of a straight vibrating rod supported by an elastic body, and an excitation means for vibrating the vibrator through the vibrating rod is provided at the other end. In the vibratory viscometer, the vibratory viscometer is provided with a displacement detection sensor that detects the amplitude of the vibration of the vibrator through the vibrating rod, in which the vibrating means is connected via an intermediate plate spring having a spring constant smaller than that of the elastic body. It is characterized in that the vibrating rod is integrated.

(Function) In the present invention, the method for measuring fluid viscosity and the vibratory viscometer are configured as described above, so that the vibrations transmitted to the elastic body by the vibrating means are transmitted to the intermediate elastic body provided on the vibrating rod. The spring constant of the intermediate elastic body can be changed regardless of that of the elastic body that supports the vibration rod, and this can be changed depending on the viscosity of the fluid to be measured. Therefore, even if the viscosity of the fluid to be measured is low, the amplitude of the vibration of this vibrator is attenuated by the viscous resistance of the fluid to be measured.

Moreover, there is no cause that changes the vibration of this intermediate elastic body, which corresponds to the change in impedance in conventional vibratory viscometers.

〔Example〕

One embodiment of the present invention is shown in the first diagram of its schematic structure.
Figure 3, which is a relationship diagram between the second factor in the plan view of the intermediate leaf spring, the frequency ratio and phase difference based on the damping coefficient ratio, and Figure 4 and Figure 4, which are explanatory diagrams of the measured viscosity of the fluid to be measured. This will be explained below based on FIG.

That is, the reference numeral (1) shown in FIG. 1 is a fluid to be measured contained in a container (2), and this fluid to be measured (1) has a vibrator (3) installed at the lower end of a vibrating rod (4). ) is immersed. The vibrating rod (4) consists of a lower vibrating rod (4a) and an upper vibrating rod (4b), which are straightly joined by a joint (5). This is done so that the damaged vibrator (3) can be easily replaced with another vibrator as in the prior art.

On the other hand, the upper vibrating rod (4b) consists of a connected body of two vibrating rods. Specifically, a first upper vibrating rod (4c) whose upper end is fixed to the center position of the lower surface of a leaf spring (7) whose outer edge is supported at the upper part of the storage case (8);
A spring support (9) having a protruding outer edge portion (9a) whose outer edge portion protrudes downward at the lower end of the first upper vibrating rod (4C).
The second upper vibrating rod (4d) has one end fixed to the center of the lower surface of the intermediate leaf spring 0■, the outer edge of which is fixed to the protruding outer edge (9a) of the second upper vibrating rod. (4
d) is provided with a brim-shaped reference plate (6).

The details of the intermediate leaf spring 0■ are as shown in FIG. It has a structure in which a pair of punched elongated holes (10a) are provided concentrically.

In addition, four through holes (10
b) is an attachment hole to the lower surface of the protruding outer edge (9a) of the spring support (9). That is, by changing the plate thickness or by setting the width and length of the punched elongated hole (10a), it is possible to easily obtain the intermediate plate spring 00) having the desired spring constant. Then, an excitation coil (
11), and an excitation device (1 1a) is disposed at two corresponding positions of the excitation coil (11), and the spring support (9) and the reference plate (6) are Optical displacement detection sensors 0 having the same structure were arranged at positions spaced apart from each other by a predetermined distance above. Next, the excitation coil 011 is connected to an amplifier (15a).
and a transmitter 05), and each of the optical displacement detection sensors 0η is manually input to the same calculation circuit 04) via a displacement meter 03).

Note that what is connected to the vibration device (Ila) via a lead wire is a power source 0(i) that operates this vibration device (lla).

The mode of action of the above embodiment will be explained below.
When lla) is activated, the leaf spring (7) vibrates via the vibration coil (11), then the first upper vibration rod (4c) vibrates, and then the vibration of the intermediate leaf spring 0ro) vibrates through the vibration coil (11). The vibration is transmitted sequentially through the vibrating rod (4d) and then through the lower vibrating rod (4a), and is transmitted to the vibrator (3). The amplitude of vibration between the first and second upper vibration rods (4c) and (4d) is measured by the optical displacement sensor 0, respectively.

Therefore, the spring constant of the intermediate leaf spring 0 is k, the total mass of the upper vibrating rod (4d), the lower vibrating rod (4a), and the vibrator (3) is m, and the fluid to be measured (1) is Assuming that the viscous resistance of is C, the equation of motion of this lower vibration system can be expressed by the following equation.

mXz +c X2 + k (x, +X2) =0
In the above formula, Each shows the acceleration.

Therefore, the amplitude Xl-. X2 is determined by measurement using an optical displacement sensor 02). Here, as X, X+ = x
+oS i n (ωt) constant amplitude χ1. If a sine wave vibration is given, X2 becomes Xz
=XzoS i n (ωt+δ), and the constant amplitude x2 is shifted in phase by δ. This results in a chordal wave vibration.

Next, by sequentially changing the angular velocity ω, a certain angular velocity value ω is obtained. When the vibrator (3) resonates, the vertical axis shows the phase difference (degrees), and the horizontal axis shows the frequency ratio (dimensionless number). is δ−π/
It becomes 2.

Therefore, while maintaining this resonance state, X. and ω are the amplitude of the oscillator (3) in a given gas as Ea, and the amplitude of the oscillator (3) in multiple types of standard viscosity liquids as En as the logarithm ffiogρ・μ on the vertical axis. When nog (Ea/E n -1) is plotted on the horizontal axis, the results are as shown in FIGS. 4 and 5.

According to these factors, the natural frequency differs depending on the thickness of the leaf spring, but all of them show excellent linearity in a certain viscosity range, so it is good to have excellent functions as a viscometer. be understood.

Furthermore, if the amplitude of any fluid to be measured is determined using these diagrams as a calibration diagram, the physical quantities ρ and μ of the lacquer body to be measured can be determined conversely.

Incidentally, these diagrams and the above equation ρ・μ−α(Ea/
E-1. ) ρ to find the constants α and β in this equation: ■ When the thickness of the vibrator (3) is 0.3 mm, α-10°
・94, β-1.72 ■ When the thickness of the vibrator (3) is 0.6 mm, α-102
・90 and β-1.64 can be obtained respectively. The physical quantities ρ and μ can be easily obtained from the measured amplitude by using a CPU or the like that inputs the data of the above-mentioned diagram.

By the way, as described above, it is necessary to apply extremely highly accurate sinusoidal vibration to the vibrator (3).

Regarding this point, in the conventional vibratory viscometer, the accuracy of sinusoidal vibration was ensured by the same vibration control path, but in the vibratory viscometer of the present invention, the vibration accuracy is ensured by the vibration device (lla). Even if it is not so good, the first upper vibration rod (4c)
A highly accurate sine wave vibration can be easily obtained by the leaf spring (7) supporting the .

However, if the spring constants of both leaf springs (7) and 00) are close to each other, the resonant frequencies of these leaf springs (7) and 00) will be the same, making measurement impossible.

According to the test results using molten slag, it was found that it is practically desirable to set the spring constant of the leaf spring (7) to a spring constant greater than eight times that of the intermediate leaf spring 0.

In other words, if the spring constants are made different, the leaf spring (7) can be vibrated almost without being affected by the resonance of the intermediate leaf spring 0.

In this way, since the intermediate plate spring 00) was used in this example, it does not require a large installation space unlike the coil springs used in conventional vibratory viscometers, and the spring constant is The thickness can be easily changed by changing the thickness, which not only makes it possible to make the viscometer more compact, but also allows it to be easily applied to measuring the viscosity of a wide range of measured fluids, from high to low viscosity. Became.

Incidentally, in the above-described embodiment, a disc-shaped intermediate plate spring 00) having a concentric curved punched long hole (10a) was used, but as shown in FIG. 6, which is a perspective view thereof, for example,
A belt-shaped leaf spring of a predetermined width is shaped into a so-called flat rhombus shape with a short vertical axis and a long horizontal axis, and a first upper vibration rod (4c) is attached to the upper part of the plate spring, and a second upper vibration rod (4c) is attached to the lower part of the plate spring. It is also possible to have a configuration in which upper vibrating rods (4d) are respectively attached.

In addition, while the spring support (9) vibrates in a high-precision sine wave by the vibration of the temporary spring (7) by the vibration device, the plate is It has been found that the spring constant of the spring (7) is sufficiently larger than that of the intermediate leaf spring (10), and that the influence of the resonance of the intermediate leaf spring 00) on the vibration of the leaf spring (7) is negligibly small. In this case, it is also possible to omit the measurement of the vibration displacement X.

Further, although the present invention has been described with reference to an example using a plate spring, it is also possible to replace this with a coil spring. However, in the case of coil springs, while torsional vibration is applied to the vibrating rod, the vibrating rod may oscillate laterally when the vibrating rod moves upward, increasing measurement errors. The problem arises that the accuracy is slightly inferior.

The above-mentioned embodiment is only one specific example of the present invention, and therefore, the scope of the technical idea of the present invention is not limited by this embodiment, and further, the scope of the technical idea of the present invention can be modified without departing from the technical idea of the present invention. Design changes etc. can be made freely.

〔Effect of the invention〕

According to the present invention, there is no cause that changes the vibration of the intermediate elastic body, which corresponds to the change in impedance in conventional vibratory viscometers, and therefore highly accurate sinusoidal resonance vibration can be applied to the vibrator. It has become possible to measure the viscosity of the fluid being measured with extremely high accuracy.

In addition, this vibratory viscometer can match the viscosity of the fluid to be measured by changing the spring constant of the intermediate elastic body, regardless of that of the elastic body that supports the vibrating rod. Not only can it be used to measure viscosity, but it can also be used to measure the viscosity of low-viscosity fluids that cannot be measured with conventional vibratory viscometers. Became.

In this way, the viscosity of the fluid to be measured can be measured with high precision regardless of the viscosity level, so the versatility and economic effects are extremely large.

[Brief explanation of drawings]

Fig. 1 is a schematic structural explanatory diagram of a vibratory viscometer according to an embodiment of the present invention, Fig. 2 is a plan view of an intermediate plate according to an embodiment of the present invention, and Fig. 3 is a vibration due to the damping coefficient ratio. A relationship diagram between a number ratio and a phase difference, FIGS. 4 and 5 are explanatory diagrams of fluid viscosity measurement results, FIG. 6 is a perspective view of an intermediate leaf spring of another embodiment, and FIG. 7 is a conventional vibration diagram. FIG. 2 is a schematic explanatory diagram of the structure of a formula viscometer. (1) One fluid to be measured, (2) One container, (3) - Vibrator,
(4) One vibrating rod, (4a)-lower vibrating rod, (4bL-one upper vibrating rod, (4cL-first upper vibrating rod, (4d)-second upper vibrating rod, (6) one reference plate, (7 ) Temporary spring, (9)
One spring support, 0[1)--Intermediate leaf spring, (10a)-
- Single punched long hole, (I1) - Excitation coil, (lla) -
1-vibration device, 0-excitation 1-optical displacement detection sensor, 03)-1 displacement meter, 041-computation circuit, 05)-1 oscillator.

Claims (2)

[Claims] (1) A vibrator detachably fixed to the free end side of a vibrating rod supported by an elastic body excited by a vibrating means is immersed in the fluid to be measured, and the vibration amplitude is attenuated by the vibration amplitude of the vibrator. A fluid viscosity measuring method for measuring the viscosity of a fluid to be measured, characterized in that vibrations from an excitation means are transmitted to the resilient body via an intermediate resilient body having a spring constant smaller than that of the resilient body. A method for measuring the viscosity of fluids. (2) A vibrator immersed in the fluid to be measured is provided at the free end of a straight vibrating rod supported by an elastic body, and an excitation means for vibrating the vibrator through the vibrating rod is provided at the other end. In the vibratory viscometer, the vibration excitation means includes an intermediate plate spring having a spring constant smaller than that of the elastic body. A vibratory viscometer characterized in that the vibrating rod is integrally formed through a vibrating rod.