JP6527342B2 - Liquid measuring device - Google Patents

Description

  The present invention relates to a liquid measurement apparatus that measures a value related to the viscosity of a liquid.

  For example, Patent Document 1 discloses a capillary viscometer provided with a flow control chamber having a flow passage cross-sectional area larger than the flow passage cross-sectional area of the differential pressure detection capillary upstream of the differential pressure detection capillary. There is.

  Further, in Patent Document 2, a movable side connected to a rotating shaft, a plurality of deformation sides parallel to each other, a hinge connecting one end of each deformation side to the movable side, and a multiend of each deformation side are fixed portions There is disclosed a rotational viscometer using a rotary shaft holding mechanism provided with at least two parallel spring links consisting of hinges connected to.

  Further, according to Patent Document 3, a liquid to be treated prepared in advance in a stirring tank is extracted, and then a servomotor is driven to rotate the stirring blade at a predetermined rotation cycle, thereby rotating the stirring blade in one cycle. Stirring configured to calculate the current viscosity of the liquid to be treated stored in the stirring tank on the basis of the pressure difference between the highest pressure and the lowest pressure and the correlation equation previously derived by experiments in advance. A device viscosity measurement method is disclosed.

  Further, in Patent Document 4, a bimorph vibrator having a drive vibrator and a detection vibrator, an oscillator for applying a drive voltage to the drive vibrator, and a position between the drive voltage and an output voltage from the detection vibrator. A phase difference detector for detecting a phase difference, and a needle-like portion to be immersed in the fluid to be measured is disposed at the tip of the detection vibrator, and is adjusted in parallel with the output of the bimorph vibrator A vibratory viscometer to which a condenser is connected is disclosed.

  In Patent Document 5, a temporary impact is applied to the container to cause the liquid in the container to have an initial behavior, and the change over time of the behavior appears in the dielectric constant measuring means for measuring the dielectric constant of the liquid. A method of determining the type of liquid in a container for determining the type of the liquid by observing the change with time of the rate signal is disclosed, and in Patent Document 6, the method is installed in the vicinity of the liquid to be measured. A capacitance sensor for measuring a capacitance value of the liquid to be measured and obtaining a dielectric constant specific to the object to be measured from the capacitance, and generating a surface wave on the liquid to be measured The fluid viscosity estimating means for estimating the fluid viscosity of the liquid to be measured from the temporal attenuation characteristics of the oscillation of the surface wave, and the dielectric constant and the fluid viscosity estimated by the capacitance sensor The object to be measured based on the fluid viscosity estimated by the means Liquid product detection unit is disclosed of identifying a body thereof.

但し、ｕ（ｔ）は変位、ｆ（ｔ）は駆動信号である。 In Non-Patent Document 1, the vibration of the liquid surface can be represented by a mechanical vibration system model of a second-order linear differential equation as shown in Equation 1, and the mechanical resistance r, stiffness s and mass m in the mechanical vibration system model are It is described that the viscosity part in the liquid surface vibration, the surface tension, and the density of the sample liquid respectively correspond.

Here, u (t) is a displacement, and f (t) is a drive signal.

JP, 2013-44643, A JP 2012-132856 A JP 2009-268981A JP, 2009-204318, A Patent No. 4901523 JP, 2011-133342, A

Yohei Kawasaki et al., Proceedings of the 2008 Tohoku Electric Power Association Association Conference, page 59, 2008

  As a method of measuring the viscosity of a liquid, as described above, a method of measuring the magnitude of resistance when stirring a liquid, a method of measuring a time of passing through a thin tube, and the like are known. However, in any method, it is necessary to directly contact the object to be measured, and in the case of performing measurement again, it is necessary to clean the device. Therefore, when measuring the viscosity change of the liquid material over time, it is necessary to repeat the measurement and the washing, and there is a limit to shortening the measurement interval even if the change in viscosity is continuously measured.

  An object of the present invention is to provide a technique capable of performing viscosity measurement of a liquid easily and continuously. Another object of the present invention is to provide a technique capable of realizing viscosity measurement of a liquid with a compact device and measuring in a wide measurement range.

  In order to solve the above problems, according to a first aspect of the present invention, there is provided a liquid measurement apparatus for measuring a value related to viscosity of a liquid, wherein the inlet through which the liquid flows and the liquid are A container having an outlet for outflow or an inlet / outlet for outflow of the liquid, an oscillating mechanism for applying vibration to the surface of the liquid in the container, and an adjacent to the container, Provided is a liquid substance measuring device having a capacitance sensor that outputs a signal according to a change in capacitance, and a measurement value generation unit that generates a measurement value based on the signal from the capacitance sensor.

  The measurement value generation unit generates the measurement value while all or part of the liquid substance in the container is replaced via the inlet and the outlet, or via the inlet and outlet. It is also good. The vibrating mechanism may be a container vibrating mechanism that vibrates the container. Alternatively, the vibration mechanism may be a mechanism that drops the liquid substance onto the surface from the inlet. Alternatively, the vibration mechanism may be a mechanism that temporally changes the flow rate at the inflow or the outflow of the liquid substance. Alternatively, the vibration mechanism may be a mechanism that generates a pulsating flow in the inflow or outflow of the liquid material.

  The measurement value generation unit may generate, as the measurement value, a value obtained by integrating an alternating current component of the signal for a predetermined cycle. Alternatively, the measurement value generation unit may generate the amplitude of the signal as the measurement value.

  Note that the above summary of the invention does not enumerate all the necessary features of the present invention. In addition, a subcombination of these feature groups can also be an invention.

FIG. 1 is a conceptual view showing an overview of a liquid substance measuring device 100. FIG. It is the graph which showed the time change of the signal in point a of FIG. 1 in the liquid substance from which viscosity differs. It is the correlation diagram which showed the relationship between the value of integral signal, and a viscosity. It is a graph which shows the measured value about some liquid substances.

  Hereinafter, the present invention will be described through the embodiments of the invention, but the following embodiments do not limit the invention according to the claims. Moreover, not all combinations of features described in the embodiments are essential to the solution of the invention.

  FIG. 1 is a conceptual view showing an outline of a liquid substance measuring apparatus 100. As shown in FIG. The liquid measurement apparatus 100 measures a value related to the viscosity of the liquid 200. The liquid substance measuring apparatus 100 has a housing 102, and has a container holder 104, a container 106, an excitation mechanism 112, a capacitance sensor 116, and a measurement value generation unit 120 inside the housing 102.

  The housing 102 is a base of the liquid substance measuring device 100, fixed against displacement and movement to be described later, and functions as an entity that provides a ground potential. For this reason, the housing 102 has a mass that does not move by vibration, and is preferably a conductor. Further, in the measurement of the capacitance by the capacitance sensor 116, it is preferable to minimize the influence of the disturbance electric field. From this point of view, it is preferable that the entire casing 102 be made of a conductor, and that the whole of the liquid measurement apparatus 100 be enclosed. An electrical shield can be configured by the housing 102 made of a conductor, and the measurement accuracy of the capacitance by the capacitance sensor 116 can be improved.

  The container holder 104 holds the container 106 and transmits the vibration from the vibration mechanism 112 to the container 106. The container holder 104 needs to have a freedom of movement at least in the vertical direction with respect to the casing 102 from the necessity of transmitting vibration to the container 106, and preferably has freedom in right and left and back and forth. When the capacitance sensor 116 described later is disposed outside the container holder 104, the container holder 104 needs to be made of a dielectric so that the capacitance can be measured through the container holder 104. If the container holder 104 does not affect the volume measurement, the material of the container holder 104 is not particularly limited. In the case where vibration is directly applied to the container 106 or in the case where vibration is applied to the surface 202 of the liquid 200 by a method other than vibration of the container 106, the container holder 104 is not essential.

  The container 106 holds the liquid 200 inside. The liquid 200 is an object of viscosity measurement. The container 106 needs to have chemical stability and mechanical strength that can hold the liquid 200. Also, the container 106 needs to be a dielectric because it is necessary to measure the capacitance through the container 106. The container 106 has an inlet 108 through which the liquid 200 flows and an outlet 110 through which the liquid 200 flows out. Here, although the example which has the inlet 108 and the outlet 110 separately is shown, the inlet 108 and the outlet 110 may be replaced with one inlet and outlet which the liquid 200 flows in and out. The container 106 may be provided with a pressure adjusting port for adjusting the pressure inside the container. For example, an opening for equalizing the pressure outside the container and the pressure inside the container may be provided as a pressure adjustment port. In this case, the opening can be provided with a filter that prevents the mixing of dust and the like. In addition, the opening for pressure control and the outlet / inlet of the liquid 200 can also be used.

  The vibration mechanism 112 applies vibration to the surface 202 of the liquid 200 inside the container 106. As the vibration mechanism 112, a container vibration mechanism for vibrating the container 106 can be exemplified. As the container vibrating mechanism, a known vibration generating mechanism can be used in addition to the mechanism using an eccentric cam as shown in FIG. In the vibrating mechanism 112 (eccentric cam) shown in FIG. 1, the speed controller 114 can change the vibration cycle.

  As the vibration mechanism 112, a mechanism that drips the liquid 200 onto the surface 202 from the inlet 108 can be exemplified in addition to the container vibration mechanism described above. In this case, it is not necessary to vibrate the container 106 itself, and the entire apparatus can be miniaturized as well as the container 106. In addition, as the vibration mechanism 112, a mechanism that temporally changes the flow rate at the inflow or the outflow of the liquid 200 can be exemplified. Also in this case, the apparatus can be miniaturized as in the mechanism for dropping the liquid material 200. In addition, as the vibration mechanism 112, a mechanism that generates a pulsating flow in the inflow or outflow of the liquid 200 can be illustrated. Similarly, the device can be miniaturized.

  The capacitance sensor 116 is disposed adjacent to the container 106 and outputs a signal according to the change in capacitance. When the surface 202 of the liquid 200 present inside the container 106 is waved by vibration, a change in capacitance according to the state of the surface wave, for example, the wave height occurs. The capacitance sensor 116 detects this change in capacitance, and the signal output from the capacitance sensor 116 reflects the wave (wave height) of the surface 202 of the liquid 200. The vibration of the liquid surface can be modeled as a second-order linear differential equation with viscosity, surface tension and density as parameters, as described in relation to the number 1 in the background art column, and the surface tension and density change Under non-conditions, the vibration of the liquid surface will depend on the viscosity part. Therefore, if the vibration of the surface 202 of the liquid 200 is measured by the change in capacitance, it is possible to estimate the viscosity portion. The ground electrode 118 can be disposed on the back of the capacitance sensor 116. By arranging the ground electrode 118, the stray capacitance of the capacitive sensor 116 can be stabilized, and the influence of the stray capacitance included in the output signal from the capacitive sensor 116 can be reduced.

  The measurement value generation unit 120 generates a measurement value based on the signal from the capacitive sensor 116. In the present embodiment, a measurement value generation unit 120 including a capacitance-frequency conversion circuit 122, a frequency-voltage conversion circuit 124, a band pass filter 126, and an integration circuit 128 is illustrated as the measurement value generation unit 120. The said measured value production | generation part 120 is an example to the last, and is not restricted to this.

  The capacitance-frequency conversion circuit 122 is a circuit that outputs a change in capacitance as a change in frequency. A general LC resonant circuit and a NOT logic circuit can be appropriately combined and configured. The change value of the capacitance converted to the frequency is converted to a voltage by the frequency-voltage conversion circuit 124. The signal converted into the voltage has its DC component removed through the band pass filter 126, and the integration circuit 128 outputs a value obtained by integrating the AC component for a predetermined period. The band pass filter 126 can remove the influence of stray capacitance and the like, and can extract a signal resulting from the vibration of the surface 202. The integration circuit 128 efficiently extracts a minute signal or properly extracts a signal including a plurality of frequencies. The output of the integration circuit 128 can be displayed on the display unit 130.

  In the liquid substance measurement device 100 of the present embodiment, all or part of the liquid substance 200 in the container 106 is subjected to measurement value generation while being replaced via the inlet 108 and the outlet 110 or via the inlet and outlet. A measurement value is generated by unit 120. Therefore, the viscosity of the liquid 200 can be continuously measured without washing the container 106 or the like.

  Further, in the liquid substance measuring device 100 of the present embodiment, the wave on the surface 202 of the liquid substance 200 is measured by the change of the capacitance to estimate the viscosity. Since the change in capacitance can be properly measured even in a situation where the liquid surface is greatly wavy, the dynamic range of measurement of the liquid measurement apparatus 100 is considerably wide. In addition, since the capacitance is measured for the entire liquid 200, it is possible to comprehensively measure the entire liquid 200, not the local viscosity of the liquid 200.

  FIG. 2 is a graph showing the time change of the signal at point a in FIG. 1 in the liquid substance having different viscosity. In FIG. 2, the signals in the liquid having viscosities of 2048 cP, 741 cP, 349 cP, 139 cP and 42 cP are shown sequentially from the top. It can be seen from FIG. 2 that an AC signal corresponding to the vibration is generated, and it can be seen that the smaller the viscosity, the larger the signal amplitude. It can be inferred that the lower the viscosity, the higher the surface wave height on the surface of the liquid, which is reflected in the magnitude of the change in capacitance.

  FIG. 3 is a correlation diagram showing the relationship between the value of the integration signal (the output of the integration circuit 128) and the viscosity. As apparent from FIG. 3, it can be seen that there is a strong negative correlation between the viscosity and the integral signal. This means that the display of the display unit 130 can be displayed as viscosity if the apparatus is calibrated using the signal of the liquid having a known viscosity.

  FIG. 4 is a graph showing measurements for several liquids. Measured values are shown for water, sugar syrup, olive oil, pork and sauce. It can be said that it is possible to measure viscosity even with a sensory, but rather viscous liquid.

  As described above, in the embodiment, the present invention has been described as the liquid substance measuring apparatus, but the liquid substance measuring apparatus of the present invention may be understood as a liquid substance measuring method and a program for realizing such an apparatus or method or function. It is possible.

  Further, the technical scope of the present invention is not limited to the scope described in the above embodiment. It will be apparent to those skilled in the art that various changes or modifications can be added to the above embodiment. It is also apparent from the scope of the claims that the embodiments added with such alterations or improvements can be included in the technical scope of the present invention. For example, the measurement value generation unit 120 can also generate the amplitude of the signal as a measurement value.

  The order of execution of each process such as operations, procedures, steps and steps in the devices, systems, programs and methods shown in the claims, the specification, and the drawings is particularly “before”, “before”, etc. It should be noted that it can be realized in any order as long as the output of the previous process is not used in the later process. Even if it is described using “first”, “next” and the like for convenience regarding the operation flow in the claims, the specification and the drawings, it does not mean that it is essential to carry out in this order.

  DESCRIPTION OF SYMBOLS 100 ... Liquid substance measuring apparatus 102 Body: 104 Container holder 106 Container 108 Inflow port 110 Outlet 112 112 Excitation mechanism 114 Speed controller 116 Capacity sensor 118 Grounding electrode , 120: measured value generation unit, 122: capacitance-frequency conversion circuit, 124: frequency-voltage conversion circuit, 126: band pass filter, 128: integration circuit, 130: display unit, 200: liquid material, 202: surface.

Claims (3)

A liquid measuring device for measuring a value related to viscosity of a liquid, comprising
A container having an inlet through which the liquid flows and an outlet through which the liquid flows out;
An excitation mechanism for applying vibration to the surface of the liquid in the container;
A capacitive sensor disposed adjacent to the container and outputting a signal according to a change in electrical capacity;
A measurement value generator that generates a measurement value based on the signal from the capacitive sensor;
Have
A liquid measurement apparatus, wherein the vibration mechanism is a mechanism for dropping the liquid onto the surface from the inlet. The liquid measurement apparatus according to claim 1, wherein the measurement value generation unit generates a value obtained by integrating an alternating current component of the signal for a predetermined cycle as the measurement value. The liquid measurement apparatus according to claim 1, wherein the measurement value generation unit generates an amplitude of the signal as the measurement value.

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