JP5916994B2 - Pressure vessel sensor for dielectric property measurement - Google Patents

Description

  The present invention relates to a pressure vessel sensor for measuring dielectric properties of various fluids such as food. Specifically, the present invention relates to a highly versatile small pressure vessel sensor for easily measuring dielectric characteristics of various fluids such as foods in a small space.

  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. An object of the present invention is to provide a highly versatile measuring instrument for the purpose.

  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.

That is, the present invention is as follows. The following (1) to (5) correspond to the respective symbols in FIG.
(I) It has a metallic cylindrical pressure vessel (2) to be an electrode and an upper and lower pressure vessel lid (1), and a columnar or cylindrical electrode (3) to be a pair of pressure vessel electrodes is parallel to the center of the vessel. Dielectric property measurement, characterized in that the columnar or cylindrical electrode (3) is insulatively guided to the outside of the pressure vessel through a conductor (5). Pressure vessel sensor for use.
(II) The pressure-resistant container sensor for measuring dielectric properties according to (I), wherein the electrode is made of stainless steel having corrosion resistance and heat resistance.
(III) The pressure-resistant container sensor for measuring dielectric properties according to (I) or (II), wherein the container volume is 20 to 30 mL.

  According to the present invention, it is possible to easily measure dielectric properties of various fluids such as gases, liquids, supercritical fluids under high temperature and pressure, and fluids in a wide range of phases such as samples dissolved in the fluids in a small space. it can. And since the container sensor of the present invention is small, high pressure resistance is ensured and can be distributed, so it is continuously used in-line, such as a small sensor for quality control in a plant, monitoring of component separation operation, etc. It can be used as a highly versatile compact dielectric container for measuring dielectric characteristics.

Sectional drawing of an example of the pressure-resistant container sensor for dielectric property measurement of this invention is shown. An example of the pressure holding structure of the fluid passage and the lead-out conductor when the dielectric property of the fluid is measured using the pressure-resistant container sensor for dielectric property measurement of the present invention is shown.

  The pressure vessel of the present invention includes a cylindrical shape and lids that are upper and lower nuts. One of the features of the present invention is that the container itself serves as an electrode by using a metal (material) made of metal 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. About the material of this columnar or cylindrical electrode, it is preferable to use the same material as the pressure vessel electrode.

  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 led to the outside of the pressure vessel through a lead wire such as Pt covered with an insulator such as Teflon (registered trademark) resin. For example, the conductor is a 1/16 inch PEEK resin with a diameter that can be passed through an insulating and pressure-resistant tube, and the PEEK resin tube that covers the outside uses a stainless steel ferrule and is 1/16 inch female nut. And tighten to 1/16 inch union tee. With such a configuration, it is possible to prevent leakage of pressure in the conductive wire portion that communicates with the outside.

  The fluid outlet of the union tee can secure a fluid passage in an insulated state by fastening a PEEK resin tube having an inner diameter of 1/16 inch with a 1/16 inch female nut using a stainless steel ferrule. In addition, the fluid outlet portion of the pressure vessel electrode is insulated to the union tee by tightening the PEEK resin tube with the same material, for example, SUS316 ferrule and male nut, and the male nut portion leads the pressure vessel electrode to the outside. Can play a role.

  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.

  A cross-sectional view of a pressure-resistant container sensor for measuring dielectric characteristics, which is an example of the configuration of the present invention, is shown in FIG. 1, and an example of a pressure holding structure for fluid passages and lead wires is shown in FIG. 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).

  In FIG. 2, a lead wire (8) covered with an insulator is led to the outside of the pressure vessel as a lead wire, and this lead wire is insulated with PEEK resin having an inner diameter of 1/16 inch and inside the pressure tube (9), (12 The PEEK resin tube covering the outside is fastened to the 1/16 inch union tee (11) with a 1/16 inch female nut (10) using a ferrule (14) made of SUS316. The fluid outlet of the union tee is tightened with a 1/16 inch female nut with a PEEK resin tube having an inner diameter of 1/16 inch using a stainless steel ferrule, and the fluid outlet portion of the pressure vessel electrode is made of ferrule and male nut made of SUS316. The insulation to the union tee is given by tightening the PEEK resin tube in (13).

  The present invention is summarized as follows.

  The present invention can be 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 the fluid, etc.). An object is to provide a highly versatile measuring instrument for measurement.

  And it has a metallic cylindrical pressure vessel electrode and upper and lower pressure vessel lids, and a columnar or cylindrical electrode which is a pair of cylindrical pressure vessel electrodes is installed in parallel with this through an insulator in the center of the vessel The columnar or cylindrical electrode can measure dielectric properties of a wide range of fluids easily and in a small space by using a dielectric property measuring pressure vessel sensor that is led out of the pressure vessel through a lead wire in an insulated state.

Claims (1)

Corrosion-resistant and heat-resistant stainless steel cylindrical pressure-resistant container electrode and upper and lower pressure-resistant container lids, and a cylindrical or cylindrical electrode paired with the cylindrical pressure-resistant container electrode is parallel to the insulator at the center of the container The columnar or cylindrical electrode is made of stainless steel having corrosion resistance and heat resistance, and is led to the outside of the container in an insulated state through a conducting wire. The container volume of the pressure vessel sensor is 20 to 30 mL. A small pressure vessel sensor for measuring dielectric properties of food continuously used in-line, characterized in that the thickness of the cylindrical pressure vessel electrode is 6 mm.

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