JP2006214930A - Viscosity measuring device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a falling ball type viscosity measuring device that measures liquid in a large range from high viscosity to low viscosity and can accurately measure it not only when it has the terminal velocity of a falling ball but also when it does not reach the terminal velocity. <P>SOLUTION: The falling ball type viscosity measuring device comprises a measuring pipe 1 for passing the liquid; the falling ball moving in the measuring pipe 1; at least one ultrasonic sensor 3 disposed in the outer periphery of the measuring pipe 1; and a means 4 for inputting and calculating an output of the ultrasonic sensor 3. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a viscosity measuring device, and more particularly to a falling ball type viscosity measuring device. In particular, the present invention relates to a viscosity measuring apparatus that is highly useful in measuring the viscosity of high-pressure liquids such as fuel oils and lubricating oils.

  Conventionally, for measuring viscosity of fuel oil and lubricating oil of diesel engine, gasoline engine, etc., and for measuring viscosity of other liquids, rotary type, cup type, falling ball (falling weight) type, mechanical vibration type, narrow tube type, etc. Liquid viscosity measuring devices using various methods have been developed.

Specifically, a vibration viscometer that measures the viscoelasticity of a liquid using a vibration sensor is frequently used. For example, a configuration as shown in FIG. The vibrating body 52 to which the vibrator 53 and the vibration sensor 54 are attached is immersed in a liquid, and a vibrating voltage is applied to the vibrator 53 to vibrate the vibrating body 52 at the resonance frequency (f ₁ ). The phase difference (P ₁ ) between the vibrator 53 and the vibration sensor 54 when vibrating at (f ₁ ) is detected, and the phase difference (P ₁ ) between the vibrator 53 and the vibration sensor 54 and the previously measured viscosity ( A method for measuring the viscosity (η) of a liquid based on the relationship with η) has been proposed (for example, see Patent Document 1).

Moreover, a drop weight type viscometer as illustrated in FIG. 14 can be given. Reference numeral 61 denotes a measuring tube set vertically, and 62 denotes a cylindrical drop weight inserted into the measuring tube. A passage detector 64a that detects the passage of the falling weight 26 from the outside of the measuring tube and transmits a signal when the falling weight 62 falls inside the measuring tube 61 by being separated by a distance L between the upper portion and the lower portion in the middle of the measuring tube 61. , And 64b are installed. These passage detectors typically applied various non-contact detection principles such as detectors using magnetic principles, detectors using electromagnetic principles, and detectors using optical principles. (For example, refer to Patent Document 2).
Japanese Patent Laid-Open No. 11-173967 JP 05-72104 A

  However, all of the above viscometers are for the purpose of measuring liquids under normal pressure conditions. When the object to be measured is a high-pressure liquid, the specifications of the viscometer in terms of structure and measurement accuracy are required. May not match. In particular, with the relatively simple viscosity measuring method as described above, it has been difficult to obtain high measurement accuracy under high pressure conditions.

  There is also a method of extracting the high-pressure liquid and measuring the viscosity under normal pressure, but the viscosity under high-pressure conditions is significantly different from the viscosity under normal pressure, so the measurement accuracy under high-pressure conditions actually used is high. There is a strong demand for viscosity measurement.

  Furthermore, for the falling ball (falling weight) type viscometer, the falling speed of the falling ball (falling weight) is accelerated at the beginning of dropping, and then the acceleration decreases due to the drag of the liquid and becomes constant (end speed). The drop time (fall distance) until it becomes depends on the viscosity (pressure) of the liquid. Therefore, it is necessary to correct the measurement result in consideration of such behavior, but it is difficult to accurately measure the behavior and it is difficult to obtain high measurement accuracy.

  In recent years, attempts have been made to improve the measurement accuracy by measuring the viscosity after reaching the end speed using the behavior of a falling ball (falling weight) that reaches the end speed. In addition, it was difficult to confirm that the viscometer was long, and when the drop time to the terminal speed was long, the viscometer might be long, so that practical application was difficult.

  In addition, when measuring a falling ball using a transmissive or reflective optical sensor, it is necessary to provide a transmissive window on the measuring tube. However, the strength of the transmissive window itself or the mounting structure is also limited by the pressure limit of the liquid to be measured. There is a limit to this, and the application is limited. For example, when sapphire having a window diameter of several millimeters to several tens of millimeters and a thickness of several millimeters to several tens of millimeters is used, the upper limit pressure is about 0.4 GPa. In particular, with respect to the seal portion of the window, it is difficult to ensure higher pressure resistance.

  Accordingly, the object of the present invention is to meet such demands, measure in a wide range from high viscosity to low viscosity, and not only when it has a falling ball end speed but also when it does not reach the end speed. An object of the present invention is to provide a falling ball viscosity measuring apparatus capable of measuring. In particular, when a high-pressure liquid is a target, it is possible to perform highly accurate measurement that has not been conventionally performed.

  As a result of intensive studies, the present inventor has found that the above object can be achieved by the following viscosity measuring apparatus, and has completed the present invention.

  The present invention is a falling ball type viscosity measuring device, a measuring tube through which a liquid passes, a falling ball moving in the measuring tube, at least one ultrasonic sensor provided on an outer peripheral portion of the measuring tube, And means for inputting and calculating the output of the ultrasonic sensor.

  As described above, in the falling ball type viscosity measuring device, it is preferable to select a measurement method that does not require the use of a member that needs to take pressure resistance, corrosion resistance, etc. into the measurement tube, It is necessary to select a measurement method that can ensure a predetermined measurement accuracy even under high pressure conditions. The present inventor uses a falling ball type measurement method in viscosity measurement, particularly viscosity measurement of a high-pressure liquid, and detects the position and behavior of a falling ball moving in a measuring tube with an ultrasonic sensor, thereby achieving high accuracy and high versatility. It was found that it can be secured.

  That is, it is possible to form a measurement system having a pressure-resistant structure for a high-pressure liquid by a combination of the falling ball measurement method and the ultrasonic sensor. In addition, the falling ball speed of the falling ball is calculated from the output of the ultrasonic sensor and the viscosity is converted, and the “speed detection error factor” in viscosity measurement such as fluttering of the falling ball (including rotation) described later is calculated from the output characteristics of the ultrasonic sensor. By performing the correction calculation, high accuracy can be ensured. Furthermore, even if the falling velocity does not reach the end velocity of the falling ball in the measuring tube, it is possible to measure the viscosity with high accuracy by calculating the falling velocity change along the falling point and estimating the terminating velocity.

  As a result, the liquid is measured in a wide range from a high viscosity to a low viscosity with a pressure-resistant structure measurement system, and not only when it has a falling ball end velocity but also when it does not reach the end velocity. It has become possible to provide a falling ball type viscosity measuring apparatus capable of measuring with high accuracy. The high-pressure liquid here refers to a liquid having a pressure of about 0.1 MPa to several GPa, such as the fuel oil and lubricating oil exemplified above.

  The present invention is the above-described viscosity measuring apparatus, characterized in that at least one of the ultrasonic sensors is arranged at the bottom of the measuring tube.

  When the object is irradiated with ultrasonic waves, the time for the reflected wave to reach the receiving unit varies depending on the distance from the object, and the intensity of the reflected wave also changes if the irradiated ultrasonic wave spreads. Further, in the measurement from the side surface of the measurement tube, there is a limit to the measurement range of a single ultrasonic sensor. The present invention performs measurement from the bottom of the measurement tube and measures the falling ball moving along the ultrasonic irradiation center axis, thereby enabling long-time measurement from the top to the bottom of the measurement tube, and determining the termination velocity and The terminal speed itself can be easily measured or estimated. Therefore, it has become possible to provide a falling ball type viscosity measuring apparatus capable of measuring with high accuracy in a state having a pressure-resistant structure measuring system.

  The present invention is the above-described viscosity measuring apparatus, wherein the ultrasonic sensor is a multi-element type sensor, and an element is arranged along a pipe line of the measuring tube.

  In the falling ball type viscosity measuring method, it is ideal to detect the falling ball speed in a state where the terminal velocity is reached. However, since the moving speed of the falling ball changes depending on the position of the measuring tube and the viscosity of the liquid, it is unclear whether the terminal velocity has been reached at the measuring point or whether such a state can occur in the measuring tube. Therefore, by using the multi-element type ultrasonic sensor and arranging the elements along the pipe line of the measurement tube, it is possible to detect the falling ball velocity at any position of the measurement tube, and the state where the terminal velocity has been reached. It is possible to detect the position or the terminal speed itself. In addition, it has become possible to provide a falling ball type viscosity measuring apparatus capable of measuring accurately not only when the falling ball has a terminal velocity but also when the falling velocity does not reach the terminal velocity.

  The present invention is a viscosity measuring apparatus using a plurality of ultrasonic sensors, in which the direction of a sound wave transmitted by one ultrasonic sensor intersects the direction of a sound wave transmitted by at least one other ultrasonic sensor. As described above, the plurality of ultrasonic sensors are arranged.

  In the falling ball type viscosity measuring method, it is ideal that the falling ball ideally falls along the central axis of the measuring tube in a state close to a stationary state. However, in reality, the position of the falling ball is displaced from the central axis and the falling ball is fluttered. As a result, the falling speed may be affected and a measurement error may occur. The detection of the falling state of a falling ball from different angles using multiple ultrasonic sensors has been found to be able to accurately grasp this phenomenon. By comparing each sensor output and correcting these factors, This makes it possible to measure the viscosity with high accuracy.

  The present invention is the above-described viscosity measuring apparatus, wherein at least one of the ultrasonic sensors is movable along a pipe line of the measuring tube.

  As described above, the moving speed of the falling ball changes depending on the position of the measuring tube and the viscosity of the liquid, so it is determined whether or not the terminal velocity has been reached by a single ultrasonic sensor provided on the side surface of the measuring tube. Can be difficult. According to the present invention, it is possible to detect the falling ball velocity at an arbitrary position of the measuring tube by moving at least one ultrasonic sensor along the pipe line of the measuring tube, and the terminal velocity has been reached. The position or end velocity itself can be detected. In addition, it has become possible to provide a falling ball type viscosity measuring apparatus capable of measuring accurately not only when the falling ball has a terminal velocity but also when the falling velocity does not reach the terminal velocity.

  The present invention is the above-described viscosity measuring apparatus, characterized by comprising means for inputting an output of the ultrasonic sensor and creating an output pattern using a time function or position function, or time or position as a parameter.

  In the falling ball type viscosity measurement method, as described above, the position of the falling ball is likely to be displaced from the central axis and the falling ball is fluttered. Further, the generation of a rotational moment of the falling ball itself may cause the falling ball to fluctuate, resulting in a measurement error (hereinafter referred to as “speed detection error factor”). In particular, such a speed detection error factor is likely to occur under high pressure conditions. The present inventor uses a time function or a position function created by calculating an output of an ultrasonic sensor, or an output pattern using the time or position as a parameter (hereinafter referred to as “output pattern etc.”) for detecting a falling ball speed. As a result, it was found that the speed changes due to the change in the falling ball speed and the error factor of the speed detection. By calculating and correcting the error factor of the speed detection from the output pattern etc., the accuracy can be improved. It has become possible to provide a high falling ball viscosity measuring device. A specific analysis method will be described later.

  The present invention is a viscosity measuring apparatus using a plurality of ultrasonic sensors or a multi-element ultrasonic sensor, and outputs an output of the ultrasonic sensor using a time function or a position function, or a time or position as a parameter. It is characterized by having means for creating a pattern and means for comparing two or more time functions or position functions or output patterns.

  As described above, it has been found that the output pattern and the like change depending on the speed detection error factor as the falling ball speed changes. However, for example, the measurement may take a long time under high pressure conditions, and the error factor of the speed detection itself may change at this time. In addition, as described above, the terminal speed may not be determined based on information of only one ultrasonic sensor related to one region of the measurement tube. Therefore, by comparing multiple output patterns of different ultrasonic sensors, analyzing the error factor of the speed detection from the difference and calculating / correcting it, more accurate fall speed is detected, The position at which the terminal speed is reached and the terminal speed can be detected from the relationship between the drop speed and the position. Therefore, more accurate viscosity measurement was possible.

  The present invention is the above-described viscosity measuring apparatus, characterized in that the measuring tube is inclined and at least one ultrasonic sensor is disposed on the lower outer side surface of the measuring tube.

  As described above, the falling ball flutter is an error factor in detecting the falling speed. However, these error factors can be greatly reduced once the drop reference line or reference plane is determined. In other words, the measurement error is reduced by detecting the behavior of the falling ball by the ultrasonic sensor provided on the outer peripheral lower side surface of the measuring tube by dropping the measuring tube along the inner surface of the measuring tube with the measuring tube inclined. It became possible to measure the viscosity more accurately.

  As described above, according to the present invention, accurate measurement of liquid viscosity, which has been difficult in the past, can be performed in a wide range from high viscosity to low viscosity with a measurement system having a simple pressure-resistant structure. It became possible to do. In particular, under high-pressure conditions, there is a high utility in that measurement can be performed with the same accuracy even in a pressure-resistant structure. Also, it is possible to provide a falling ball viscosity measuring device that can accurately measure by creating an output pattern of an ultrasonic sensor, comparing and examining the relationship with error factors of speed detection, and calculating / correcting. It has become possible.

  In particular, by moving a single ultrasonic sensor to enable measurement at an arbitrary position on the side surface of the measurement tube, or by appropriately arranging a plurality of ultrasonic sensors or multi-element ultrasonic sensors, The behavior such as speed or flicker can be grasped more accurately, and the viscosity can be measured with higher accuracy.

  In addition, it is possible to accurately measure the viscosity not only when the terminal velocity of the falling ball is reached but also when the terminal velocity is not reached, which has been difficult in the past.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

<Basic configuration example (first configuration example)>
FIG. 1 illustrates a basic configuration of a viscosity measuring apparatus according to the present invention. A measuring section comprising a measuring tube 1 having a flow path through which a liquid to be measured passes, a falling ball 2 moving in the measuring tube 1, and an ultrasonic sensor 3 provided on the outer periphery of the measuring tube 1, A viscosity measuring device is formed by means (calculation unit) 4 for inputting and calculating the output of the ultrasonic sensor 3. Further, FIG. 1 illustrates a configuration having a plunger 5 provided at the uppermost part of the measuring tube 1 and fixing the falling ball 2 and a contact 6 for detecting that the falling ball 2 has reached the lowermost part of the measuring tube 1. Needless to say, the present invention is not limited to such a configuration.

Here, since the viscosity is influenced by the environmental temperature at the time of measurement due to its characteristics, the viscosity measuring device is preferably used under conditions where the change in the ambient temperature is small. When there is a possibility that the environmental temperature changes, it is preferable to provide means (not shown) for detecting the liquid temperature in the vicinity of the ultrasonic sensor 3. By inputting the detected temperature data to the calculation unit 4 and correcting the measurement data as described later, accurate viscosity measurement can be performed. The specific viscosity value targeted by the present application is not particularly limited, but 10 ⁻³ to 10 ⁸ Pa · s is suitable under high pressure conditions.

  The measuring tube 1 is not particularly limited as long as it is usually a pressure resistant material, but from the viewpoint of strength, workability of the inner tube, uniformity of the inner surface, etc. A reinforcing pipe into which a ceramic inner pipe is inserted is suitable. Moreover, although the magnitude | size of the measuring tube 1 changes with use conditions, such as a measurement object and a liquid pressure, generally it uses the tubular body which has an internal diameter of several mm-several tens mm, and has a length of several tens mm-several hundreds mm. Can do.

  The size of the falling ball 2 is not particularly limited, but a sphere having a diameter of about 50 to 80% of the inner diameter of the measuring tube 1 can be usually used. The material is not particularly limited as long as it has a specific gravity capable of obtaining a predetermined falling speed with respect to the high-pressure liquid. However, metal, glass, ceramics, etc. are used because of spherical workability and lubricity. Is preferred. Further, by using an iron ball, a steel ball, or the like, it is possible to adopt a method for facilitating fixing before dropping or detecting after dropping, as will be described later.

  Regarding the ultrasonic sensor 3, as an element constituting the sensor, an electromagnetic vibrator using Lorentz force, a vibrator using a piezoelectric effect of piezoelectric ceramic, or the like can be used. In FIG. 1, the transmission unit and the reception unit are illustrated as an integrated member from the viewpoint of convenience of mounting the sensor, but the present invention is not limited to this, and it is also possible to use a combination of separate bodies. .

  In addition, a method of irradiating the falling ball 2 with the ultrasonic wave from the transmitting unit and receiving the reflected wave (reflection type), and a method of detecting the block by the falling ball 2 by always irradiating the receiving unit with the ultrasonic wave from the transmitting unit (transmission type). However, in order to detect the behavior of the falling ball 2, the reflection type as shown in FIG. 1 is preferable. It is possible to detect changes in the falling ball over time, such as whether or not the falling ball 2 is in an accelerated state, whether or not there is a flicker, by a reflected wave more accurately than the transmission type.

  Furthermore, in order to effectively use ultrasonic energy and improve detection sensitivity, it is preferable to adopt a method (focusing method) in which ultrasonic waves are emitted from the transmitting unit so that the reflected wave is focused on the receiving unit. In the experiment of the present inventor, high accuracy could be ensured by using the focus type ultrasonic sensor 3.

  When the position at which the falling ball 2 reaches the terminal speed can be estimated in advance, it is preferable that the ultrasonic sensor 3 is installed at a lower position than that position. However, since the terminal speed can be calculated from the output pattern or the like of the ultrasonic sensor 3 under a predetermined condition even when the position to be the terminal speed is unknown, the sphere is used for calculating the terminal speed. It is preferable to use the falling speed at a location close to the bottom as long as it is not affected by the above. When various liquids need to be measured, it is preferable to provide a guide (not shown) that can change the installation position of the ultrasonic sensor 3 on the outer periphery of the measurement tube 1. Further, as in a configuration example described later, it is possible to use a plurality of ultrasonic sensors and multi-element sensors, or to move the sensors along the measurement tube 1 using a moving mechanism.

  The calculation unit 4 has a function (write data) for continuously receiving and sequentially writing the output of the ultrasonic sensor 3, and a data input function for receiving an input from the operation unit of the viscosity measuring apparatus or an input from a transmission means such as temperature data. The reference output data of the ultrasonic sensor 3 when a liquid having a known viscosity obtained in advance is detected, the correlation between the falling speed and the viscosity (regardless of how the data is stored, such as function data or a table to be compared) Functions to store data, creation of output patterns using write data or stored data, comparison of multiple output patterns, correction of output patterns, etc. Built-in functions. It is also preferable to incorporate a function for correcting the environmental temperature in calculating the viscosity and a function for correcting variations in output characteristics among a plurality of ultrasonic sensors.

The measurement is operated and processed as exemplified below.
(1) At the time of measurement, the liquid is preferably in a stopped state, and the introduction of the liquid is stopped for a predetermined time before the measurement. As a stopping method, it can be performed by blocking with a solenoid valve provided in a flow path connected to the measuring tube 1 (not shown).
(2) A voltage is applied to the plunger 5 and the falling ball 2 is fixed by an electromagnet. At this time, by reducing the fixed portion of the falling ball 2 (for example, the front end portion of the electromagnet), it is possible to reduce the occurrence of a moment different from the falling direction acting on the falling ball 2 away from the fixed portion.
(3) When the liquid becomes stable, the voltage applied to the plunger 5 is turned off, and the falling ball 2 starts to fall. As the falling ball 2 falls, the output of the ultrasonic sensor 3 increases and eventually decreases.
(4) When the falling ball 2 reaches the lowermost part of the measuring tube 1, the falling ball 2 comes into contact with the contact 6 to which a voltage is applied in advance. At this time, since the surface potential of the contact 6 changes, it can be detected that the falling ball 2 has reached the lowermost part of the measuring tube 1, and one measurement cycle is completed.
(5) The liquid stopped state by the electromagnetic valve of (1) above is canceled, and the liquid to be measured next is introduced into the measuring tube 1 to be in a stable state. When sufficient accuracy cannot be obtained in the above one measurement cycle, (1) to (4) after repeating (1) to (4) or after introducing the same liquid into the measurement tube 1 again. By repeating the above and calculating an average value or a deviation value, it is possible to ensure viscosity measurement with a desired accuracy.

  The liquid is preferably introduced from the lower part of the measuring tube 1. When the above steps (1) to (4) are completed, the falling ball 2 can be transferred to the upper part of the measuring tube 1 by introducing a liquid, and the voltage is applied to the plunger 5 again (2). The falling ball 2 can be fixed to the plunger 5 as shown in FIG. By performing these operations automatically, the functionality of the apparatus can be improved.

At this time, it is preferable to input the output of the ultrasonic sensor 3 to the calculation unit 4 and create an output pattern using a time function or time as a parameter. Specifically, the former is calculated using time as a parameter based on the continuous output of the ultrasonic sensor 3 (normally a multidimensional function, but may be approximated to a quadratic or cubic function for convenience of calculation processing. The output function is preferable. As the latter, as illustrated in FIG. 2, a correlation is created as a pattern with time on the horizontal axis and the output of the ultrasonic sensor 3 on the vertical axis, and created as output / time data on the pattern. it can. At this time, it is possible to create an output pattern or the like based on the output itself of the ultrasonic sensor 3, that is, the echo height h, but the output of the ultrasonic sensor 3 on the inner surface of the measurement tube in the installed state. The height h ₀ of the echo (when no ball is present) is obtained, the echo height h when the falling ball 2 passes is standardized to obtain the echo height ratio H (H = h / h ₀ ), and based on this It is preferable to create an output pattern or the like.

From such an output pattern or the like, the falling speed v of the falling ball 2 can be calculated, and the amount of change (that is, acceleration) α of the falling ball speed can be calculated and corrected by the error factor of the speed detection described above. That is, based on data such as output patterns of a plurality of liquids having known viscosities, the height Hm and the half-time width T of the pattern shown in FIG. 2A and the time half of the center line M shown in FIG. Judgment whether or not the falling velocity v or the terminal velocity v ₀ of the falling ball 2 has been reached due to the difference in the magnitudes of the values Ta and Tb before and after the value range, or analyzing and calculating the error factor of the velocity detection Is possible.

(1) The magnitude of the drop speed v is correlated with the half-time width T. That is, when the drop speed v is large, the half-time width T is small because the detection speed of the ultrasonic sensor 3 comes out in a short time, and vice versa when the drop speed v is small. From this, as shown in FIG. 2C, the terminal speed (for example, v ₀₁ , v ₀₂ , v ₀₃ ) and the half-value width (for example, T ₀₁ , T ₀₃ ) such as output patterns of a plurality of liquids having known viscosities. ₀₂ , T ₀₃ ), the correlation between the two (which can also be expressed by a correlation function) is obtained in advance, and the drop velocity v corresponding to the half-time width Tx of the subject can be obtained.

(2) Also, the magnitude of the drop velocity v can be estimated in advance by determining the relationship between the echo height ratio H in the ultrasonic sensor 3 and the position of the falling ball 2. That is, as shown in FIG. 2D, the echo height ratio H in a state where the falling ball 2 is suspended from the top of the measuring tube 2 at a fixed position under the condition where there is no high-pressure liquid is obtained in advance. An output pattern having a horizontal axis at a position such as) is created. At this time, the output pattern, etc., by normalizing the echo height ratio H _0, for example, as 1.0 at irradiation center axis M ₀ of the ultrasonic wave, such as variations in the output and the angular distribution of the ultrasonic sensor 3 itself The influence can be ignored. Further, in the measurement method according to the present invention, particularly when the focus type ultrasonic sensor 3 is used, the influence of the measurement method having a wide viewing angle such as the difference of the medium through which the ultrasonic wave is transmitted and the refraction of the sound wave is almost due to the diffusion of the sound wave. Since it can be ignored, highly accurate estimation is possible.

(2-1) Specifically, when an output pattern or the like having the time of FIG. 2 (A) as a parameter is obtained by an ultrasonic sensor having an output pattern or the like having the position of FIG. 2 (E) as a parameter, For example, by obtaining the half-value width G (representing the distance between two half-value points) in FIG. 2E and dividing by the half-value width T (representing the time between two half-value points) in FIG. falling speed v of the irradiation center axis M ₀ can be determined. That is, the output value in both output patterns created based on the standardized echo height ratio H corresponds to the measured value of the falling ball 2 at the same position at the same time. For example, the point P in FIG. Figure 2 (E) P 'in, _{since t 2} and _g 2, _{t n} and _{g n} are the corresponding similarly, it is possible to calculate the speed by a distance G which has moved during the time T.

(2-2) Further, by extending the technical idea of (2-1), it is possible to track the change in the drop velocity v. Specifically, the time t ₁ , t ₂ , t ₃ in FIG. 2 (A) corresponding to the echo height ratio H at the subdivided positions g ₁ , g ₂ , g ₃ . ₂ is calculated and v ₂₁ = (g ₂ −g ₁ ) / (t ₂ −t ₁ ), v ₃₂ = (g ₃ −g ₂ ) / (t ₃ −t ₂ ). By tracking the change as shown in (F), it is possible to estimate the terminal velocity v ₀ described later.

(3) Whether or not the terminal speed v ₀ has been reached has a correlation with values before and after the center line M of the half-time width T in FIG. 2A (Ta and Tb). That is, in the acceleration state, the time after the center time of the detection region of the ultrasonic sensor 3 is shorter than that before the center time, and when the terminal speed is reached, both times are substantially the same. Therefore, it is possible to determine whether or not the terminal speed v ₀ has been reached by calculating Ta and Tb in the output pattern or the like.

(4) Whether or not the terminal velocity v ₀ has been reached is correlated with the front and rear areas Sa and Sb in FIG. That is, in the acceleration state, the amount of the reflected wave is smaller after the center time of the detection area of the ultrasonic sensor 3 than before the center time, and when the terminal speed is reached, both times are substantially the same. Accordingly, it is possible to determine whether or not the terminal speed v ₀ has been reached by calculating Sa and Sb in the output pattern or the like.

  (5) Regarding the fluttering of the falling ball 2, the closer the falling ball 2 is to the ultrasonic sensor 3, the stronger the reflected wave is, and the farther the reflected ball is, the weaker the reflected wave is. It can be inferred that an output pattern or the like to which a noise-like component is added as exemplified in FIG. Accordingly, a plurality of output patterns and the like are obtained in advance using a liquid having a known viscosity. For example, the output pattern and the like are standardized with the output of the peak P being 1.0, and a plurality of points ( For example, when the standard function is a quadratic function, the coefficient of the standard function is determined by calculating using data of 3 points and 4 points if the standard function is 3), and the output pattern is approximated to the standard function. Thus, it is possible to correct the flutter of the falling ball 2. At this time, it is possible to improve the correction accuracy by setting a threshold value for the deviation value from the standard function among the measurement values of the subject and not using the measurement result when the threshold value is exceeded. By using the corrected output pattern or the like for the calculation of the falling ball velocity in (1) above, a highly accurate viscosity measurement value can be obtained.

<Second configuration example>
FIG. 3 illustrates a second configuration example of the viscosity measuring apparatus according to the present invention. At least one ultrasonic sensor 3 is arranged at the bottom of the measuring tube 1. That is, the ultrasonic wave irradiated from the ultrasonic sensor 3 normally propagates in the sound axis direction and spreads in the radial direction. When the falling ball 2 moves near the sound axis of the probe attached to the bottom surface, the echo from the falling surface can capture the movement information.

Specifically, as shown in FIG. 3A, an ultrasonic sensor 3 is disposed at the bottom of the measuring tube 1 and an ultrasonic wave that increases as the falling ball 2 falls is detected. it can detect the terminal velocity v _0. For example, as shown in FIG. 3B, the echo height ratio H increases as the falling ball 2 falls, and the path length difference ΔL (time difference ΔT × sound velocity c) between the bottom surface echo and the spherical echo decreases. The drop speed v at that point is obtained by time differentiation of the path difference, and the terminal speed v ₀ can be estimated from the tendency of the speed. However, the sound velocity c of the liquid is required for calculating the drop velocity v, and the value is used when it can be estimated, and when it is unknown, the side surface of the measuring tube 1 at a position (known value) from the bottom surface is used. It is also possible to obtain a sound velocity c of the liquid from the difference in reflection time from the falling ball 2 and the bottom surface when the falling ball 2 passes on the sound axis at that position by attaching a focus type ultrasonic sensor 3 ′ to the surface. .

  Since the moving speed v can always be measured based on the same surface of the falling ball 2 by the at least one ultrasonic sensor 3, it is possible to configure a measuring apparatus with very high measurement accuracy. Further, according to the configuration of FIG. 3B, an unprecedented technical effect that the sound speed of the liquid can be measured simultaneously with the measurement of the viscosity can be obtained. In particular, it is difficult to actually measure the speed of sound under high pressure conditions, which is one of the excellent technical effects of this configuration.

<Third configuration example>
Next, another configuration of the viscosity measuring apparatus according to the present invention is illustrated in FIG. A plurality of ultrasonic sensors 31, 32, and 33 are arranged along the pipe line of the measuring tube 1, and a function surface or accuracy surface that is limited in the case of one ultrasonic sensor described in the basic configuration. Can be complemented and compensated by using a plurality of ultrasonic sensors.

  Specifically, as shown in FIG. 4, the position at which the terminal speed is reached, the confirmation of the terminal speed, and the error in the speed detection are detected by arranging in the vicinity of the terminal speed area to be estimated and distributed in the area. The presence / absence of the influence of the factor and the degree of the influence can be detected. At the time of measurement, the following processing is performed on the output pattern of each ultrasonic sensor. As a premise, it is assumed that the output characteristics of each ultrasonic sensor are equivalent and do not vary between sensors, or are corrected. Further, the accuracy can be further improved by normalizing the outputs of these ultrasonic sensors as described above.

(1) The terminal velocity can be estimated or calculated from the falling velocities v ₁ , v ₂ , v ₃ detected by a plurality of ultrasonic sensors. In other words, the drop velocities v ₁ , v ₂ , and v ₃ from the half-value widths T ₁ , T ₂ , and T ₃ in the output patterns and the like of each of the plurality of ultrasonic sensors are used using the characteristics shown in FIG. Can be obtained. If it is not equivalent as shown by the solid line in FIG. 5A, the terminal velocity v _{0 is} obtained by calculating the correlation between the position of each sensor and the falling velocity, with the vertical position of the measuring tube 1 as the horizontal axis. Can be estimated. As shown by a broken line in FIG. 5A, the drop velocities detected by the ultrasonic sensors 33 and 32 (or 31 may be equivalent) located below the measurement tube 1 are equivalent (v ₃ ′ = v ₂ ′). = V ₀ ), the value is set as the terminal speed.
Alternatively, as shown in FIG. 5 (B), the position of the measuring tube 1 in the vertical direction is taken as the horizontal axis, and the correlation between each sensor position and the half widths T ₁ , T ₂ , T ₃ is obtained, By calculating the value width T ₀ and using the characteristics shown in FIG. 2C, it is possible to estimate the terminal speed.
Further, before and after the half-width center line M, if Ta ₁ and Tb ₁ are equivalent, T ₁ is based on T _1. If Ta ₁ and Tb ₁ are not equivalent and Ta ₂ and Tb ₂ are equivalent, T ₂ Based on the above, if both are not equivalent and Ta ₃ and Tb ₃ are equivalent, the terminal speed can be estimated based on T ₃ .

(2) Regarding the fluttering of the falling ball 2, if the heights H ₁ , H ₂ and H ₃ at the sensor outputs are different, it can be inferred that there is fluttering. Therefore, it is possible to correct the flutter of the falling ball 2 by approximating the output pattern or the like to a standard function based on the average value of each height or the average value obtained by excluding the value most deviating from the average value. Become.
Alternatively, if there are a large number of sensor outputs that reach the terminal speed, the average value can be used as the standard output pattern.
By using the output pattern and the like corrected in this way for the calculation of the falling ball speed in (1) above, it is possible to obtain a highly accurate viscosity measurement value.

<Fourth configuration example>
In the above configuration, as illustrated in FIG. 6, the direction of the sound wave transmitted by at least one of the plurality of ultrasonic sensors (31 to 35) is different from that of the other ultrasonic sensors. By arranging so as to intersect the direction of the sound wave transmitted by (31 to 33), it becomes possible to configure a more accurate measurement system (fourth configuration example).

  That is, by detecting the falling state of the falling ball 2 from different angles with the plurality of ultrasonic sensors 31 to 35, it is possible to grasp the flickering of the falling ball 2 two-dimensionally. By correcting these factors, errors in viscosity measurement can be greatly reduced. In particular, when the falling ball 2 at the same position is simultaneously detected from different angles by the ultrasonic sensors 32 and 34 and 33 and 35, it is possible to obtain information on the falling speed and error factors that cannot be grasped by detection in one direction. It becomes possible.

Specifically, the output patterns (A) to (E) of the ultrasonic sensors 31 to 35 as exemplified in FIG. That is, assuming the following conditions, the terminal speed v ₀ can be calculated and corrected as in (1) to (3).
The heights H _{31 to} H ₃₃ in (A) to (C) are set to substantially the same value.
(A) is greater than the half-width _{T 31} is _T 32 _{through T 35,} and _{Tb 31} is greater than _{Ta 31} for before and after the half-width.
(B) and (C) have substantially the same half width T ₃₂ or T ₃₃ .
In (D), the height H ₃₄ is higher than H ₃₂ or H ₃₃ , and the peak P ₃₄ is shifted backward from the center line M.
In (E), the height H ₃₅ is smaller than H _{31 to} H ₃₃ and H ₃₄ .

(1) From the relationship between the output patterns of the ultrasonic sensors 31 to 33, etc. (A) to (C), it can be determined that the terminal speed has been reached at the position of the ultrasonic sensor 32. That is, it can be determined based on the half width T ₃₂ or T ₃₃ and the relationship between Ta ₃₁ and Tb ₃₁ . Accordingly, the terminal velocity v ₀ can be obtained from the correlation corresponding to FIG. 2C using the half width T ₃₂ or T ₃₃ (= T ₃₂ ) at this time.

(2) the output pattern, etc. in FIG. 7 (C) and (E), i.e., the height H ₃₅ from lower than other output pattern or the like, fluctuation occurs in falling ball 2, or the trajectory of (E) It shows that it is shifted from the center of the measuring tube 1. However, since there is no height variation in (A) to (C), it is possible to determine that there is no fluttering of the falling ball 2 and the trajectory is deviated from the center of the measuring tube 1. Thus, the correction of the terminal velocity v ₀ of the (1) can be determined to be unnecessary.

In the determinations of (1) and (2) above, when the terminal speeds stabilized in (B) and (C) have been reached, the half-value width T in (C) considered to be in a more stable state. It is preferable to determine the terminal velocity v ₀ using ₃₃ . Further, in the above assumption, the case where correction is unnecessary is illustrated, but when correction is necessary, correction with high accuracy can be performed by the method illustrated in Configuration Example 3.

<Fifth configuration example>
A fifth configuration example of the viscosity measuring apparatus according to the present invention is illustrated in FIG. The ultrasonic sensor 3 is a multi-element sensor, and elements (for example, 3a, 3b, 3c,...) Are arranged along the pipe line of the measuring tube 1. For example, it can be said that the ultrasonic sensor 3 is configured by using the ultrasonic sensors 31, 32, 33 in the third configuration example as one element. And accurate detection of the terminal speed can be performed.

  Specifically, in the ultrasonic sensor 3 composed of multiple elements arranged in the measuring tube 1 as shown in FIG. 8, for example, at the start of detection, the uppermost element 3a is operated and detected, and sequentially 3b, 3c,. By switching and detecting the operating element, the falling speed of the falling ball 2, that is, the terminal speed can be detected. At this time, even when liquids having different viscosities are measured, when the viscosity is high, the elements 3a, 3b, 3c,... Are operated in order, and when the viscosity is low, the elements 3a, 3c,. Operate by skipping the elements, or when the viscosity is high, the detection is completed only with the elements 3a, 3b, 3c, and when the viscosity is low, operate all the elements such as the elements 3a, 3b, 3c,. Can do. In this way, switching can be performed according to conditions such as liquid properties, required measurement accuracy or measurement time, and a highly versatile measuring apparatus can be configured.

<Sixth configuration example>
FIG. 9 illustrates a sixth configuration example of the viscosity measuring apparatus according to the present invention. The ultrasonic sensor 3 is movable along the pipe line of the measuring tube 1. For example, by moving the ultrasonic sensor 3 at the same speed as the falling ball 2 along the pipe of the measurement tube 1, it is possible to detect the terminal speed range and accurately detect the terminal speed. Further, by detecting the speed difference with the falling ball 2 by moving the ultrasonic sensor 3 along the pipe of the measuring tube 1 with several constant speed moving sections, it is possible to detect the terminal speed range and the terminal speed. It is possible to accurately detect.

Specifically, as shown in FIG. 9, the ultrasonic sensor 3 is arranged in the moving mechanism Z arranged in the measuring tube 1, and, for example, at the start of detection, the ultrasonic sensor 3 is arranged at the uppermost position to drop the ball. 2 detects sequentially 3b, in accordance with the fall 3c · · and falling ball 2 by detecting moving the ultrasonic sensor 3, the falling speed v clogging falling ball 2 can detect the terminal velocity v ₀ . At this time, it is possible to move at the same speed as the falling speed of the falling ball 2 more accurately by changing the moving speed up and down by a small width so that the output of the ultrasonic sensor 3 becomes maximum. Further, the moving speed of the ultrasonic sensor 3 can be calculated based on the amount of operation in the moving mechanism, such as the number of rotations when a servo motor is used.

  Even when liquids with different viscosities are measured, the moving speed of the ultrasonic sensor 3 is lowered when the viscosity is high, and the moving speed of the ultrasonic sensor 3 is raised when the viscosity is low. The movement conditions can be changed according to the measurement accuracy or the measurement time, which makes it possible to configure a highly versatile measurement apparatus.

<Seventh configuration example>
In the above configuration example, the case where the measurement tube 1 is arranged in the vertical direction has been described. However, deviation of the position of the falling ball from the central axis or fluttering of the falling ball, which is one of the error factors of the speed detection, can be greatly reduced if the reference line or reference plane of the fall is determined. That is, as illustrated in FIG. 10, it is preferable to place the measurement tube 1 in an inclined state and dispose at least one ultrasonic sensor on the lower outer peripheral surface of the measurement tube (seventh configuration example).

  Specifically, the measuring tube 1 is inclined and the falling ball 2 is dropped along the inner surface of the measuring tube 1. Similar to the above configuration example, the ultrasonic sensor 3 is provided on the outer peripheral surface of the measurement tube to detect the behavior of the falling ball 2. Here, since the lower surface of the inner surface of the measuring tube 1 is a reference, by disposing at least one ultrasonic sensor so that the surface of the falling ball 2 in contact with the lower surface can be detected, It becomes possible to detect with high accuracy in a state where the flutter is reduced.

  Further, the inner surface of the measuring tube 1 is not cylindrical, and it is also possible to have a V-cut surface (see FIG. 10A) or a U-cut surface on the lower surface. However, if a V-shaped groove is dug in the inner surface of the measuring tube 1, stress concentration may occur under high pressure and the pressure vessel may be destroyed. As illustrated in FIG. 10B, the measuring tube 1 It is preferable to attach the guide rail 7 so that the falling ball 2 passes through the center.

  Attach to the pressure vessel with adhesive. When the contact with the falling ball 2 is performed at one point in the cross section of the measuring tube 1 (the locus of the drop is a single line), there is a possibility of causing a flutter at the time of dropping due to vibration or a position shift at the start of dropping. However, since the falling ball 2 can be supported by two points on the V-cut surface or the U-cut surface (the trajectory of falling is two lines), a stable falling state can be ensured and more accurate. It is possible to measure the viscosity.

<Other embodiments>
The above describes the viscosity measurement (volume modulus) of a liquid, particularly a high-pressure liquid, but as described in the second configuration example, the sound velocity of the liquid can be measured by using the configuration of the present invention. Also, the sound velocity of the high-pressure liquid can be measured by applying the fourth configuration example.

  Specifically, as illustrated in FIG. 11, consider a case in which the falling ball 2 is falling substantially at the center of the measuring tube 1. For example, as described below, the liquid sound velocity C when the center of the falling ball 2 is slightly shifted from the center of the measuring tube 1 is given by the following equation (1).

C (T ₁ + T ₂ ) ≈2 (D−d) = CT ₃ −2d (Expression 1)
Here, T ₁ represents a time difference between an echo on the inner surface of the measurement tube in the ultrasonic sensor 31 and an echo on the surface of the falling ball, and T ₂ represents an echo on the inner surface of the measurement tube in the ultrasonic sensor 32 and an echo on the surface of the falling ball. T ₃ is a round-trip propagation time in the liquid when a sound wave propagates through the inner diameter D of the tube and is reflected by the inner surface on the opposite side, in the absence of a sphere. Therefore,
_{C = 2d / (T 3 -T} 2 -T 1) ·· ( Equation 2)

Explanatory drawing which shows the fundamental structure (1st structural example) of the viscosity measuring apparatus which concerns on this invention. Explanatory drawing which illustrates schematically the output pattern etc. of an ultrasonic sensor in the viscosity measuring apparatus which concerns on this invention. Explanatory drawing which shows the 2nd structural example of the viscosity measuring apparatus which concerns on this invention. Explanatory drawing which shows the 3rd structural example of the viscosity measuring apparatus which concerns on this invention. Explanatory drawing which illustrates the correlation with the position of an ultrasonic sensor, a fall speed, or a half value width. Explanatory drawing which shows the 4th structural example of the viscosity measuring apparatus which concerns on this invention. Explanatory drawing which illustrates schematically the output pattern etc. of the ultrasonic sensor in a 4th structural example. Explanatory drawing which shows the 5th structural example of the viscosity measuring apparatus which concerns on this invention. Explanatory drawing which shows the 6th structural example of the viscosity measuring apparatus which concerns on this invention. Explanatory drawing which shows the 7th structural example of the viscosity measuring apparatus which concerns on this invention. BRIEF DESCRIPTION OF THE DRAWINGS Explanatory drawing which shows the outline of the sound speed measuring apparatus which used the structural example for this invention. Explanatory drawing which shows schematically the structure of the vibration type viscometer which concerns on a prior art. Explanatory drawing which shows schematically the structure of the falling weight type | formula viscosity meter which concerns on a prior art.

Explanation of symbols

1 Measurement tube 2 Falling ball 3 Ultrasonic sensor 4 Calculation means (calculation unit)
5 Plunger 6 Contact point v Falling speed v ₀ Ending speed H Echo height ratio T Half width (time half width)

Claims (8)

  A falling ball type viscosity measuring apparatus, a measuring tube through which a liquid passes, a falling ball moving in the measuring tube, at least one ultrasonic sensor provided on an outer peripheral portion of the measuring tube, and an ultrasonic sensor And a means for inputting and calculating an output.   The viscosity measuring apparatus according to claim 1, wherein at least one of the ultrasonic sensors is disposed at a bottom of the measuring tube.   The viscosity measuring apparatus according to claim 1, wherein the ultrasonic sensor is a multi-element sensor, and an element is disposed along a pipe line of the measuring tube.   A viscosity measuring device using a plurality of ultrasonic sensors, wherein the direction of the sound wave transmitted by one of the ultrasonic sensors intersects the direction of the sound wave transmitted by at least one other ultrasonic sensor, The viscosity measuring apparatus according to claim 1, wherein the plurality of ultrasonic sensors are arranged.   The viscosity measuring apparatus according to claim 1, wherein at least one of the ultrasonic sensors is movable along a pipe line of the measurement pipe.   6. The viscosity measuring apparatus according to claim 1, further comprising means for inputting an output of the ultrasonic sensor and creating an output pattern using a time function or a position function, or a time or position as a parameter. .   A viscosity measuring apparatus using a plurality of ultrasonic sensors or a multi-element ultrasonic sensor, and inputs an output of the ultrasonic sensor to create a time function or a position function, or an output pattern using time or position as a parameter. The viscosity measuring apparatus according to claim 1, further comprising: means and means for comparing two or more time functions, position functions, or output patterns. The viscosity measuring apparatus according to claim 1, wherein the measuring tube is inclined and at least one ultrasonic sensor is disposed on an outer peripheral lower surface of the measuring tube.

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