JPH01162129A - Attenuation coefficient measuring apparatus - Google Patents

Abstract

PURPOSE:To measure viscous resistance without directly applying an external force to an object to be measured, by a method wherein a carrier having a container housing the object being measured fixed thereon is turned as a whole by a specified angle against an energization thereof and then, kept vibrating freely. CONSTITUTION:A container 50 housing an object to be measured is placed on a carrying plate 21 to be fixed securely in place and a carrier 20 is turned as whole by a specified angle against the energization of a rotary energizer 30 and then, kept vibrating freely. As a result, the vibration turns to an damping vibration and the amplitude or rotational cycle thereof is detected with a detector 40. Then, a data processing of a logarithmic attenuation factor, namely, attenuation coefficient of a detection thereof, for example, with a microcomputer thereby calculating viscous resistance of the object being measured.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an attenuation coefficient measuring device, and particularly to one suitable for measuring viscous resistance of semi-solid or semi-liquid materials such as yogurt.

[Prior art and problems to be solved by the invention] There are four types of conventional devices for measuring viscous resistance, that is, viscosity meters, such as capillary viscometer, rotational viscometer, and vibrational viscometer. To the best of the inventor's knowledge, there is no suitable solid or semi-liquid material that easily loses its original shape when external force is applied, such as yogurt. In other words, a capillary viscometer cannot be used with this type of product because it does not cause capillary phenomenon, whereas a rotational viscometer fills the space between a movable outer cylinder and a fixed inner cylinder with the object and applies rotation at a constant angular velocity to the movable outer cylinder. In order to measure the force couple caused by viscous resistance, the object breaks at the contact surface between the inner and outer cylinders and the object, and only a couple force different from that caused by the original viscous resistance can be expected. In this case, a vibrator is placed inside the object housed in a container, vibrated vertically, and the damping coefficient of the vibration is measured, which results in the object being crushed by the vibrator, which is also not the original purpose. It was not expected to obtain a viscous resistance value.

[Means for Solving the Problems] The present invention aims to solve the above-mentioned conventional problems, and includes storing a semi-solid or semi-liquid substance such as yogurt in a container, and By applying forced rotational vibration and determining the vibration damping rate from the damping process, it is possible to calculate the viscous resistance.

The present invention will be explained with reference to FIGS. 1 to 7, which correspond to embodiments. In the figures, 10 is a support device, 20 is a stage, and 3
0 is a rotation urging device, and 40 is a detector. Support device 10
The support arms 13.
13 is fixed horizontally, and the support arm 13 is provided with a pair of upper and lower pivot bearings 14 and 14. Also, the loading table 20
The support shaft 22 supports the center of the lower surface of the mounting plate 21 on which the container 50 containing the object to be measured is placed.
has an opening 23.23 through which the support arm 13 is inserted, and a pair of upper and lower pivot pins 24.2 are inserted into this opening 23.
The zero-rotation biasing device 30 has a pivot pin 24, 24 which is supported by the pivot-shaped bearings 23, 23, respectively, and is rotatable with minimal frictional braking during rotation. The support shaft 2 is connected to the lower end of the shaft 22.
2 to apply damped rotational vibration. Furthermore, the detector 40 detects and outputs the rotation amplitude or rotation period of the support shaft 22.

Here, the principle of the present invention will be explained with reference also to FIGS. 8 and 9.

In Fig. 8, J is the inertia coefficient of inertial body 1 (Kg*cm・s2)
, C is the viscous resistance coefficient (Kg fist cm/rad/s)k for the rotational movement of the inertial body 1 by the dashpot 2
Spring constant of spring 3 (Kg * cta/rad)
Using these, if we show a typical example of rotational motion with one degree of freedom, we get Jd2θ/dt2+Cdθ/dt+ kθ=M(t)・
−(1).

The damped free vibration equation J (
The general solution of θ=O to d2θ, 7dt2) +C(dθ/dt)+ is given as follows. That is, θ=C+
esIt +C2es2t-(2) where c, , c2 are arbitrary constants, and Sl.

S2 is the solution to the equation %. That is, 51.2 = -(C/2J)± (C/2J)2- (k/J)Here, the form of equation (2) differs depending on whether Sl,2 is a real number or a complex number. , (C/2J) < (k/J), it becomes a damped vibration. That is, Sl, 2 = -(C/2J) ±jrC] ding - (C/2J) 2, and since it includes an imaginary number, the solution includes 6jdt, and eJ'
=cos a+ iS:! From the relationship Ia, θ= e-(C/2J)t(C1' cos q t + C2'
gin q t) However, C1'=CI +C2, C2'=j (C+ -C2)
becomes.

This solution is a combination of a decreasing exponential curve and a harmonic curve, as shown in Figure 9, e-(C/2J)t and -6
-(C/2J)t It becomes a damped vibration that oscillates while decreasing.

In addition, when (C/2J)2 > (k, /J), 3
1 and S2 are both negative real numbers, so 6SIt.

Both eS2t form an exponential curve that decreases. Also (C/
2J) When 2 = (k/J), Sl.

S2 = -(C/2J), which is an equal root of real numbers and is also non-periodic.

However, even if the damping is a little smaller than this, it will still be vibration, so as a state at the boundary between vibration and no period, (C/ 2 J) 2
= (k/m) = The critical damping constant Ce of the state in an2 is: Ce=2Jω.

(an is the resonant frequency).

In the damped free vibration state as shown in FIG. 9, the torsion width ratio of successive vibrations is taken, the n-th amplitude is an, and the n+1-th amplitude after one period (T=2π/q) is a7. 1
Then, an / al*l += e (C/ 2
J) T= 6('CO/JQ) = constant, and it is a constant value no matter what peak of vibration is taken. In other words, the amplitude decreases in a geometric progression.

Taking the logarithm of this ratio, δ=log (an/anal) = πC/J
It becomes q.

The attenuation coefficient a measuring device according to the present invention calculates this δ, that is, the logarithmic attenuation rate, from the measurement data, and thereby allows the viscous drag coefficient C to be calculated, C= (δJ/π)・When C is found from q= (δJ/π)・(k/J)−(C/2J)2, it becomes C=2δ k/(4π2+62).

Therefore, the inertia coefficients Jo and J when nothing is placed on the plate 21 and when the container 50 is placed on the plate 21.
l, the spring constant k can be made common and known, and the influence of friction on rotational vibration can be minimized, the swinging rotation of the support shaft 22 is detected by the detector 40, and the logarithmic damping rate is determined from the detected value. By determining δ, the viscous drag coefficients Co and C under the above two conditions can be obtained, and from the difference between both values, the container 50
The viscous drag coefficient of the object within is calculated.

Here, the inertia rate JO and spring constant ko of the entire system when nothing is placed on the mounting plate 21 are calculated using an additional mass whose inertia rate J2 is known as follows.

That is, in general, the resonant frequency ωn of a rotational motion meter is an =
It is expressed as "JTi has completed".

The resonant frequency ωn1 without any additional mass is ωnl''A
Fuwa T The resonant frequency ωn2 in a state where there is an additional mass is expressed as ωn2=pressure]goTgogoT. Therefore, from the above two equations, ωn12/ω1122=(JO+J2)/j.

Therefore, Jo = (iJ++2/ (Q)I112-ω1
122) ) to XJ2 = (an 12 *ωnz2/(ωn12-ωnz2))
It becomes XJ2.

In addition, the rotation period T of the stage 20 is measured, and from T=2π/q Q= (k/J)-(C/2J)2 =2π/T,
It is also possible to determine the viscous drag coefficient C. That is, from these two equations, C=2J (k/J)-(2π/T)2.

Of course, the above calculation can be easily performed using a data processing device using a microcomputer or the like.

[Operation] Next, the operation will be explained. The container 50 containing the object to be measured is placed on the mounting plate Jl and fixed so as not to shift, and the entire mounting plate 20 is rotated by a predetermined angle against the biasing force of the rotational biasing device 30. Let it be free and vibrate freely. This vibration then becomes a damped vibration as described above, and the detector 40 detects its amplitude or rotation period. Then, by redata processing the logarithmic attenuation rate, that is, the attenuation coefficient, of this detected value using, for example, a microcomputer, the viscous resistance of the object to be measured is calculated.

[Example] Embodiments of the present invention will be described below based on the drawings.

In the figure, 10 is a support device, 20 is a stage, 30 is a rotation urging device, and 40 is a detector.

The support device 10 has a thick long column-shaped support 12 erected at one corner of a substantially triangular base 11, and screws 15 for leveling adjustment are provided at each corner.

Miki support arms 13, 13 are horizontally fixed to the column 12, and bearings 14 are provided at the tips of the arms, respectively. This bearing 14 has a conical depression in the center.
In the upper support arm 13, the recess is directed upward, and in the lower support arm 13, the recess is directed downward. Note that the support arm may be made of one tree, or may be made of three or more trees.

The stage 20 is composed of a thin disc-shaped stage plate 21 and a support shaft 22 attached to the center of the lower surface of the stage plate 21 .

The support shaft 22 is a hollow cylinder with two holes 23.2 in the middle.
3 is a provision. This aperture 23.23 is connected to the support arm 1
The opening is slightly wider than the cross-sectional area of the support arm 13 at a position corresponding to the support arm 13.13 so that the support arm 13.13 can be inserted therethrough with plenty of room. Further, mounting seats 25 and 26 are fitted into the upper and lower ends of the support shaft 22, respectively, and the upper mounting seat 25 is fixed to the mounting plate 21, and the rotational biasing device 30 is attached to the lower mounting seat 26. It is.

A spring 27 and a pin 24 are embedded in the upper mounting seat 25, and the spring 27 urges the pin 24 to protrude downward. A pin 24 is also fixed to the lower mounting seat 26 by protruding upward.

Then, the support arm 13.
The stage 20 is assembled to the support device so that the pins 24, 24 are engaged with the bearings 14, 14 of the support arm 13, respectively. That is, the tip of the pin 24 matches the top of the recess of the bearing 14 to form a so-called pivot bearing, and the combination is such that no friction occurs when the support shaft 22 is rotated. When the upper bearing 14 and the pin 24 are engaged, the spring 27 urges the pin 24 to protrude downward, and the reaction force of this urging force causes the lower pin 24 to push up the lower bearing 14. . Therefore, the support shaft 22 is sufficiently supported by only the bias from one side, and the upper and lower bearings 14 and the pin 24
It can be rotated horizontally using the line connecting the point of contact with the tip as the axis of rotation.

However, since the opening diameter of the aperture 23 is only slightly larger than the cross-sectional area of the support arm 13, the rotation angle of the support shaft 22 is limited. A rotation angle of about 5° was appropriate.

The rotation biasing device 30 is provided with a linear groove 31 on the lower end surface of the mounting seat 26 at the lower end of the support shaft 22, and a plate spring 33 sandwiched between a pair of liners 32 is fitted and fixed in this groove 31. 33 is supported at both ends by roller guides 34. The roller guide 34 has a roller holder 37 with a pair of built-in rollers 36 attached to a fixed base 35 erected on a base.
, 36 are formed with a groove 38 so as to create a gap between them.
The end of the leaf spring 33 is inserted into the groove 38.

Further, the roller holder 37 has a tip end portion 37a that holds the roller 36 in a tapered trapezoidal shape, and the fixing base 35 has a corresponding trapezoidal notch groove 35a. For this reason,
By fitting and fixing the tip portion 37a of the roller holder 37 into the notch groove 35a of the fixing base 35, the roller 36 can be easily positioned with respect to the leaf spring 33 without using a measuring instrument or the like.

Note that the depth of the groove 38 of the roller holder 37 is the same as that of the leaf spring 33.
It is sufficient that the tip of the leaf spring 33 does not touch the bottom of the groove in the shape S (Fig. 6) with no bending, that is, the leaf spring 33 is not bent on the support shaft 22.
This is because as the groove rotates, it bends away from the groove bottom as shown in FIG.

Further, the width of the groove 38, especially the opening portion, is slightly increased in consideration of the displacement in the width direction due to the deflection of the leaf spring 33.

Of course, since this @force biasing device M30 biases rotational force to the support shaft 22, it does not use a plate spring as in the illustrated example, but may be a helical spring or the like. However, it is necessary to use a shaft that has as little frictional resistance as possible to the rotation of the support shaft 22.

For example, a potentiometer can be used as the detector 40. In the illustrated example, an arm 41 is attached to the lower end surface of the mounting seat 26 on the lower side of the support shaft 22, and the arm 41 and the detector 40
The rotational displacement of the support shaft 22 can be extracted as an electric signal by connecting the support shaft 22 to the arm 42 with a pin. Of course, the detector 40 may be of any type, but like the rotational biasing device 30, it needs to have as little frictional resistance to the rotation of the support shaft 22 as possible.

In the figure, reference numeral 60 denotes an operating device, in which four pillars 61 are erected on the base 11, a disc-shaped holding plate 62 is fixed to the top of the pillars, and an operating panel 63 is rotatably placed on the holding plate g162. Something,
It is installed with the support shaft 22 inserted through the center. Hold 5
An angle scale 64 is carved on the side of each of the operation g162 and the operation fi63, so that the rotation angle of the operation fi63 can be displayed. Note that 65 in the figure is an operating lever. In addition, the support shaft 22 is loosely inserted into both the holding 5162 and the operation 5163, and there is no relation to the rotation of the support shaft 22.Although not shown in the figure, the operation 5163 is fixed in position with respect to the holding 5162 by an appropriate means. It is possible to do so.

A stopper device 70 is attached to the upper surface of the operation panel 63 via an L-shaped metal fitting 66. This stopper device 70 includes a stopper bin 72 and a stopper bin 72 inside a case body 71.
A locking pin 73 is provided for use. Stopper pin 7
The stop pin 73 is urged by a spring 74 to protrude to the side opposite to the support shaft 22 and is disposed horizontally. It is biased upwardly and placed vertically. When the stopper pin 72 is pushed in the direction of the support shaft 22 and locked with the locking pin 73, the tip of the stopper pin 72 has a length that can engage with the plurality of pins 21a protruding from the lower surface of the loading plate 21. be.

Next, the operation and operation of the apparatus of this embodiment when measuring the viscosity of the object to be measured stored in the container 50 will be explained.

First, the stopper pin 72 of the stopper device 70 is fully pushed into the case body 71 so that it protrudes toward the lower surface side of the loading plate 21.
The operating device 60 is locked in this state with the locking pin 73.
The operation panel 63 is rotated by the operation lever 65, and the tip of the stopper pin 72 is brought into contact with one of the pins 21a on the lower surface of the loading plate 21.

Next, the container 50 containing the object to be measured, such as yogurt, is placed and fixed on the loading plate 21, and the operation panel 63 is further rotated by a predetermined angle, for example, 5 degrees. This can be confirmed by the provided angle scale 64. Moreover, this rotation angle of course differs depending on the object to be measured. Then, due to the contact between the stopper pin 72 and the pin 21a of the loading plate 21, the cutting table 2 consisting of the loading plate 21 and the support shaft 22
0 rotates together with the operating panel 63, and the leaf spring 33 of the rotational biasing device 30 deforms as shown in FIG.

In this state, the operation 5163 is fixed so as not to rotate, and the locking pin 73 is pulled down against the biasing force of the spring 76.
When the stopper pin 72 is released from the recess 75, the stopper pin 72 immediately moves in the direction opposite to the support shaft 22 due to the biasing force of the spring 74, and the contact between its tip and the bottle 21a is released.

Then, the stage 20 begins to rotate in the opposite direction to the previous rotation operation direction due to the elastic biasing force of the deformed leaf spring 33, and further rotates back and forth in accordance with the freely damped vibration of the leaf spring 33. An electric signal corresponding to the rotational displacement of the support shaft 22 is transmitted to the detector 40.
is output from. The vibration curve drawn by the output of the detector 40 at this time becomes a damped vibration curve as shown in FIG. Since the damped vibration curve is different from the damped vibration curve in a state where the container 50 is not placed on the stage 20. Therefore, if you collect vibration data in advance when nothing is placed on the stage 20, you can compare it with the vibration data when the container 50 is added as described above to determine the measurement target. Can calculate the viscous resistance of objects.

Note that the device of the present invention does not directly measure viscous resistance, but outputs damped vibration data, so the measurement target is not limited to viscous resistance.

[Effects of the Invention] Since the damping coefficient measuring device according to the present invention is as described above, it is possible to suppress the vibration by simply applying a slight forced vibration to the object to be measured, without directly applying an external force to the object. This has the effect of being able to measure the damping state and collect electrical measurement data from which viscous resistance can be calculated.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of an embodiment of the present invention, FIG. 2 is a front view of the same, FIG. 3 is a partial sectional view of the front of the same, FIG. 4 is a partial sectional view of the same side, and FIG. 5 is the same detector. FIGS. 6 and 7 are plan partial cross-sectional views of the rotational biasing device, and FIGS. 8 and 9 are explanatory diagrams showing the principle of the present invention. 10: Support device 11: Base 12: Support column 13: Support arm 14: Bearing
20: Loading table 21: Loading plate 22: Support shaft 23: Opening hole 24: Bin 30: Rotation biasing device 40: Detector

Claims (1)

[Claims] A support device includes a support arm horizontally fixed to a column erected on a base, and a pair of upper and lower pivot-shaped bearings provided on the support arm, and a support plate at the center of the lower surface on which a container containing the object to be measured is placed. is supported by a support shaft, and the support shaft is provided with a pair of upper and lower pivot pins at positions corresponding to the pivot-shaped bearings of the support arm, and the pivot pins are supported by the pivot-shaped bearings to be freely rotatable. It consists of a table, a rotational urging device that is linked to the support shaft and applies damped rotational vibration to the support shaft, and a detector that detects and outputs the rotational amplitude or rotation period of the support shaft. Attenuation coefficient measuring device