JP5907586B2 - Pressure-resistant container sensor for measuring dielectric characteristics and method for changing measurement conditions - Google Patents

Description

  The present invention relates to a small pressure vessel sensor for measuring dielectric characteristics of various fluids such as food and a method for changing the dielectric characteristics measurement conditions.

  Since substances have inherent dielectric properties, they can exhibit dielectric polarization when placed in an electric field, and can know capacitance, dielectric constant, dielectric loss, dielectric relaxation, and the like. These characteristics directly reflect the state of motion of atomic groups and molecules. Therefore, measuring the dielectric characteristics is an effective means for detecting the molecular state of the constituent component in the measurement sample and its change.

  Since the measurement of dielectric properties is an effective means that can be directly measured under nondestructive conditions, it has been widely applied in the fields of food, medicine, chemistry, and the like. Application examples include the moisture content and the state of deterioration of edible oil (for example, Patent Document 1), the quality control of seasonings such as sauces from a macroscopic viewpoint, and the monitoring of the number of cells at the fermentation site. Can be mentioned. In the medical field, a method for non-invasively measuring blood glucose level from the skin has been devised (Patent Document 2). It is also applied to the measurement of alcohol content in mixed fuel.

  In the extraction of food materials and functional substances from natural products, it is necessary to select an appropriate solvent for the target solute. Conventionally, extraction processes using solubility parameters as an indicator of dissolution behavior have been studied. ing. The solubility parameter is defined by the latent heat of vaporization, and it is empirically known that the closer the solubility parameter value between the solute and the solvent is, the higher the compatibility is, and it is used as a guideline for judging the solubility. However, it is difficult to fit between materials having high hydrogen bonding properties.

  On the other hand, it is possible to actually measure the overall dielectric characteristics of each substance in an electric field, not only in a single phase but also in a mixed phase. When measuring the change in dielectric properties, when a dielectric (measurement sample) is inserted in an electric field region where the electrode surface area (S) and the distance between electrodes (d) are constant, the dielectric constant (ε) and the electric capacity (C) Is represented by C = ε (S / d). Therefore, since the electric capacity (C) can be easily measured by using an impedance analyzer or an LCR meter, a change in dielectric constant of the measurement sample can be measured as a change in electric capacity. Further, since it is reported that the smaller the dielectric constant difference between the solute and the solvent is, the higher the mixing property is, like the solubility parameter, it is possible to select an appropriate solvent by measuring the electric capacity.

  In this way, measuring the dielectric properties of various fluids such as foods has the great advantage of being able to directly observe these physical changes and properties in a non-destructive manner. From this point of view, there is a tendency that the measuring apparatus is enlarged and the structure needs to be changed depending on the properties of the fluid to be measured. For this reason, there has been a demand for the development of a highly versatile measuring instrument for simply measuring the dielectric properties of a wide range of fluids.

JP 2005-515436 A JP 2010-188135 A

  The present invention is widely applied to various fluids such as food (gas, liquid, various fluids such as supercritical fluid under high temperature and high pressure, and samples dissolved in fluid), and easily measures dielectric properties in a small space. It is an object of the present invention to provide a highly versatile measuring instrument and a suitable configuration thereof.

  In order to achieve the above object, as a result of intensive studies, the present inventors have developed a small pressure vessel sensor for measuring dielectric characteristics having the following configuration. The following (1) to (5) correspond to the respective symbols in FIG.

  A cylindrical cylindrical pressure vessel (2) serving as an electrode and an upper and lower pressure vessel lid (1), and a columnar or cylindrical electrode (3) serving as a pair of pressure vessel electrodes is disposed in parallel at the center of the vessel. A pressure-resistant container for measuring dielectric characteristics, characterized in that the columnar or cylindrical electrode (3) is installed via (4) and is led to the outside of the pressure-resistant container via a conducting wire (5). sensor.

  Further, the present inventors have further developed the following present invention for simply (easily) changing the dielectric structure measuring pressure vessel sensor and a new configuration of the dielectric characteristics measuring pressure vessel sensor.

(I) In the pressure-resistant container sensor for measuring dielectric characteristics, the cylindrical or cylindrical electrode (3) and the pressure-resistant container electrodes (1), (2) in the center of the container are made of the same material, and both electrodes A dielectric container container for measuring dielectric characteristics, characterized in that an interval between both electrodes is fixed by an insulative insulator (4).
(II) The dielectric property measurement condition of the sensor according to (I), wherein only the shape of the columnar or cylindrical electrode (3) at the center of the container is changed. Simple change method.
(III) The method according to (II), wherein only the diameter of the cylindrical portion of the columnar or cylindrical electrode at the center of the container is changed.

  According to the present invention, in a pressure-resistant container sensor for measuring dielectric properties, which can easily measure dielectric properties of fluids in a wide range of phases such as gases, liquids, and supercritical fluids in a small space, the counter electrode is made of the same material. By doing so, it is possible to easily change the volume of the electric field, the distance between the electrodes, the electrode surface area, etc. (that is, the conditions for measuring the dielectric properties) simply by changing the shape such as the diameter of the columnar or cylindrical electrode at the center of the container.

Sectional drawing of an example of the pressure-resistant container sensor for dielectric property measurement is shown. The structural example of this invention is shown. The left side shows a cylindrical electrode whose diameter is larger than that of FIG. 1, and the right side shows an example of application of the cylindrical electrode to a pressure vessel.

  The pressure-resistant container of the pressure-resistant container sensor for measuring dielectric characteristics is composed of a cylindrical shape and lids that are upper and lower nuts. One of the characteristics is that the container itself plays a role as an electrode by using a metal material such as stainless steel. As a result, it is not necessary to install a plate electrode or a cylinder-type electrode that has been conventionally used in the pressure vessel, and the size of the vessel and the simplicity of the design are realized. In particular, by using a material having high corrosion resistance and high heat resistance such as SUS316 as a material, it can be applied to a severe reaction field such as a supercritical fluid. The columnar or cylindrical electrode inside the container that forms a pair with this is installed in parallel with the cylindrical pressure-resistant container via an insulator.

  The dielectric property measuring pressure vessel sensor measures the dielectric properties of the target fluid between the counter electrodes. In the present invention, the columnar or cylindrical electrode is made of the same material as the pressure vessel electrode and both. Since the distance between the two electrodes is fixed by an insulator in close contact with the electrodes, the volume of the electric field, the distance between the electrodes, and the electrodes can be easily changed by changing the shape of the columnar or cylindrical electrode, particularly the diameter of the body portion. The surface area and the like can be easily changed, that is, the dielectric property measurement conditions can be easily changed.

  The container volume is about 20 to 30 mL, and the thickness of the cylinder is about 6 mm. Thereby, it is small and can hold | maintain high pressure | voltage resistance. The outer surface of the pressure vessel is preferably coated with an insulating material having excellent heat resistance and chemical resistance, such as polytetrafluoroethylene (PTFE), in order to protect it from external electrical interference. The columnar or cylindrical electrode is guided to the outside of the pressure vessel through a lead wire such as Pt covered with an insulator such as Teflon (registered trademark) resin.

  The purpose of such a dielectric property measurement container is to place a fluid and measurement sample in a pump or the like under a suitable temperature condition with a heater or oven, etc., and achieve a suitable pressure condition with a back pressure valve or regulator. Measure the dielectric properties. For example, the dielectric characteristics are measured by connecting an LCR meter or an impedance analyzer to the dielectric characteristics of the dielectric in the low frequency to high frequency range of 10 Hz to 100 MHz.

  The fluid to be measured includes all solvents such as water, methanol, ethanol, acetone, n-hexane, phenol, chloroform, dichloromethane, acetonitrile, carbon dioxide, mixed solvents thereof, and supercritical fluids thereof. With respect to the solute component, polar components such as hydrocarbon compounds such as terpenoids and fatty acids, polyphenols, and carbohydrates are mainly targeted. In addition, the food itself composed of these solvents and solutes is also an object to be measured, and is characterized by being able to measure fluids having various viscosities.

  Examples of the present invention will be described below, but the present invention is not limited to these examples.

  FIG. 1 shows a cross-sectional view of an example of the configuration of a dielectric container measuring pressure vessel sensor for simply measuring dielectric characteristics in a small space. In FIG. 1, a metallic cylindrical pressure vessel (2) and upper and lower pressure vessel lids (1) constitute a pressure vessel electrode, and a columnar or cylindrical electrode (3 ) Are installed in parallel via an insulator (4), and a pair of columnar or cylindrical electrodes (3) are led to the outside of the pressure vessel via a lead (5) in an insulated state. The surface of the pressure vessel is provided with an insulating coating (6).

  Next, as an example of the present invention, FIG. 4 shows a case in which a cylindrical electrode having a body diameter larger than that in FIG. 1 is used. In this example, the cylindrical electrode (right side) and the pressure vessel electrode at the center of the container are made of the same material, and the interval between the two electrodes is fixed by an insulator that is in close contact with both electrodes. The volume of the electric field, the distance between the electrodes, and the electrode surface area can be easily changed from the conditions shown in FIG.

  The present invention is summarized as follows.

  It is an object of the present invention to provide a versatile measuring instrument that can be widely applied to various fluids such as foods and simply measure dielectric properties in a small space, and to provide a suitable configuration thereof. To do.

  And it has a metallic cylindrical pressure vessel and an upper and lower pressure vessel lid to be an electrode, and a columnar or cylindrical electrode to be a pair of pressure vessel electrodes is installed in parallel with this via an insulator in the center of the vessel In the pressure-resistant container sensor for measuring dielectric properties, the columnar or cylindrical electrode is led to the outside of the pressure-resistant container through a conducting wire, and the pressure-resistant container electrode is the same as the columnar or cylindrical electrode in the center of the container. A material is provided that has an interval between the electrodes fixed by an insulator that is in close contact with the electrodes. The dielectric property measurement conditions can be easily changed by changing only the shape of the columnar or cylindrical electrode at the center of the container.

Claims (1)

A cylindrical pressure vessel electrode and an upper and lower pressure vessel lid are provided, and a columnar or cylindrical electrode that is a pair of the cylindrical pressure vessel electrode is installed in parallel through an insulator at the center of the vessel. In the pressure-resistant container sensor for measuring dielectric properties, the container volume of the pressure-resistant container sensor is 20 to 30 mL and the wall thickness of the cylindrical pressure-resistant container electrode is 6 mm. food columnar or cylindrical electrodes and the cylindrical pressure vessel electrode of the central part which is made of stainless steel, and, characterized by spacing that is fixed, between the two electrodes by adhesion is an insulator to the electrodes small pressure vessel sensors for dielectric property measurement.

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