JP2005134359A - Method and instrument for measuring degrees of changes in component and property of aqueous solution - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve a problem wherein daily coping-with in a field is not able because expert knowledge, labors and time as in measurement of a COD value and a BOD value, detection of a contained substance by chemical analysis and instrumental analysis and the like are required for investigation of water pollution and a deterioration condition, and control of a factory waste liquid and various kinds of aqueous solutions used in a production field such as a water-soluble oil agent, in the conventional art, so as to be carried out daily by a worker having no expert knowledge in the field. <P>SOLUTION: An electrostatic capacity of a sensor is varied in response to a component and a property of a substance contained in water, when a capacitor type sensor having an outer surface coated with an insulation coating film is immersed into the aqueous solution, as shown in Figure. Pollution and a degree of deterioration of water, and a concentration of the aqueous solution is determined based on a numeral value of the electrostatic capacity therein. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method and apparatus for detecting the state of change in the component properties of water, and covers the outer surface of an electrode formed by inserting and electrically bonding two conductive plates having the same shape and area with an insulating film. Using a sensor with the above-mentioned structure, it is extremely easy to measure in real time for the determination of contamination and deterioration of factory effluent and household wastewater, contamination of water-soluble metal oils such as water-soluble cutting oil, determination of deterioration, and concentration control. It relates to a method and equipment.

Conventionally, detection of COD value and BOD value is generally used for measurement of water pollution and deterioration. Moreover, as a water quality test, generally, the purpose is to measure the content of a specific dissolved substance, and a dedicated measuring instrument or analyzer, or a method based on chemical analysis is used.
Some optically measure water quality easily and in real time. (For example, refer to Patent Document 1).

However, these methods are not a method for comprehensively determining the degree of contamination and deterioration of water and for anyone to carry out easily at the factory site. Also, there is no water quality measuring device like the present invention that utilizes capacitance at present.
Japanese Patent Laid-Open No. 11-37940

  In the modern age of material civilization, mass production and mass consumption are the most important propositions. However, on the other side, natural destruction and environmental pollution occur simultaneously. Both are exactly one side. Among them, water pollution is the environmental problem most familiar to us.

  And the measure is not to pollute the water and to recycle the sewage. In order not to pollute the water, it is necessary for the person using the water to always observe and control the degree of contamination of the water.

  However, at present, in order to manage irrigation water, a certain amount of knowledge and special equipment are required, and it is not easy for anyone. Therefore, at the current production site, workers cannot directly and appropriately perform concentration management and waste liquid treatment on the aqueous solution used.

  Various water-soluble solutions are used at the manufacturing site, but it is necessary to determine the degree of deterioration for proper concentration management and performance maintenance. However, at present, there is no appropriate means for simply performing on-site, and some PH meters, refractometers, etc. are used as a convenience, but there are many problems and they have not been widely used. . That is, the PH meter is subject to determination of acid and alkalinity, but the degree of contamination is greatly influenced by factors other than the PH value, and in the case of contamination and deterioration, the measurement resolution is low and inaccurate. The refractometer has some resolution for solutions but is not suitable for suspensions and emulsions.

  The present invention can be applied to all solutions such as solutions, suspensions, emulsions, etc., sufficiently satisfies the on-site requirements for water quality management, does not require special knowledge, and can be measured very easily in real time. is there.

  Generally, when different solids or solids and liquids come into contact, charge transfer occurs from one to the other at the contact surface, and one of them is positively charged with the other being negatively charged. Now, when two conductor plates with the same shape and area are inserted and bonded with an insulating plate, charges of opposite signs of the same polarity are induced on both conductor plates. If a dielectric is sandwiched between them, it becomes a single capacitor and induces a specific capacitance.

  Two conductor plates with the same shape and area are bonded by inserting an insulating plate, and the outer surface is covered with an insulating film to form a capacitor. When this is immersed in water, it dissolves or disperses in water. The capacitance that appears on the sensor changes sensitively depending on the composition and properties of the substance (experimental facts). By detecting this change in capacitance with a detector and displaying it digitally, the degree of difference in water quality can be detected.

  When measuring the concentration of an aqueous solution (emulsified liquid, suspension) using this sensor, it has been confirmed by experiments that the concentration and the indication of the sensor are in a generally proportional relationship. From this, if the inherent change rate is measured for the aqueous solution used, the corresponding concentration can be easily known from any measured value. In the case of waste liquid management, waste liquid management can be performed appropriately if a disposal standard value by this measuring device is determined in advance.

  However, when the polarity of the substance dissolved in the aqueous solution to be measured is high, the influence remains on the sensor and does not easily return to the reference value. Therefore, when a highly polar sample is measured, it is more reasonable to update the sensor. Therefore, the sensor is a disposable type and has a simple detachable structure.

  As described above, according to the present invention, determination of the concentration of the aqueous solution and subtle differences in water (aqueous solution, emulsion, suspension) can be easily measured in real time. The measurement example is shown below. FIG. 5 relates to various types of water, and shows measured values of purified water, tap water, and mineral water. Not only mineral water with different hardness but also subtle differences in tap water with different water sources are detected.

  6, FIG. 7, FIG. 8, and FIG. 9 are measured values for an aqueous solution, a translucent aqueous solution, an emulsion, and a suspension, respectively. That is, FIG. 6 shows the relationship between the concentration of ascorbic acid and the measured value (sensor indication value). As can be seen from the figure, it has been confirmed by experiments that the concentration and the sensor indication value are in a directly proportional relationship. Therefore, the concentration can be easily determined by the calibration curve. FIG. 7 shows the relationship between concentration and measured value for a commercial household detergent (shampoo). FIG. 8 shows the relationship between concentration and measured value for commercial milk. FIG. 9 shows the relationship between the concentration of milk powder (coffee creep) and the measured values. In either case, Japanese Pharmacopoeia purified water was used as the solvent.

  In this way, since any solution can be considered that the indicated value is proportional to the concentration, it is possible to easily determine the concentration and manage the irrigation water by making a calibration curve for the used solution.

  FIG. 9 shows the results of measurement of a nearby aqueous solution for reference. As described above, since one aspect of each characteristic can be digitized and displayed for any aqueous solution, the application range as a measuring instrument is extremely wide.

  A feature of the present invention is the structure of the sensor. That is, two electrode plates of equal size made of electrical conductors are bonded via an insulating plate (dielectric) to form a capacitor-like electrode pair, and the entire outer surface thereof is covered with an insulating film to form a sensor. The sensor is usually attached to the sensor holder, but the connection is completely waterproof.

  When this sensor is immersed in water, the capacitance changes according to the component properties of the substance contained in the water. This change is detected by a capacitance measuring instrument, and the contamination of water and the degree of deterioration are determined or the concentration of the aqueous solution is managed. The capacitance that appears in the sensor varies depending on the contact area of the sensor with water. Therefore, the measurement is performed by immersing the entire sensor electrode in water.

  When the disposable sensor according to claim 2 is used, when the entire sensor is immersed in the liquid, water enters from the insertion portion to the measurement portion, and measurement becomes impossible. Therefore, it is necessary to perform measurement by immersing a part of the sensor while keeping the contact area with water constant. However, it is difficult to keep the sensor and water immersion area constant in freehand. In this case, the sample is filled in a measurement container having a certain depth corresponding to the sensor, and the tip of the sensor is attached to the bottom surface of the container for measurement.

  FIG. 1 is a block diagram of the entire present invention. In FIG. 1, reference numeral 1 denotes a sensor electrode, and its capacitance changes depending on the change in the component properties of the liquid. Reference numeral 2 denotes a holder for holding the sensor electrode. Reference numeral 4 denotes a detection unit that detects capacitance induced in the sensor electrode, and the display unit 5 and the power supply unit 6 are integrated, and are connected to the sensor electrode holder by the connection cable 3.

  FIG. 2 is a plan view of the sensor electrode, and FIG. 3 is a sectional view thereof. Reference numeral 7 is a conductor plate, which is formed of two electrodes having the same shape and size, and is bonded via an insulating plate 8, and its outer surface is covered with an insulating film 9 to form an integral structure, thereby forming a capacitor-like sensor. Yes. Reference numeral 10 denotes a lead for electrode connection.

  FIG. 4 shows a container for measurement when a disposable sensor is used. The container has a double structure. Reference numeral 11 denotes an inner cup which is integrated with the outer cup 12. The inner cup is a container with a certain depth set according to the area of the sensor. It always fills and uses the sample and keeps the liquid level constant. The outer cup temporarily stores the liquid overflowing from the inner cup. By using a container having such a structure, an accurate measurement value can be expected.

    Processing fluids containing water such as water-soluble cutting oils and water glycol hydraulic fluids are widely used at metal processing sites, but contamination and deterioration of the fluids adversely affect processing performance, machine operation and maintenance. Therefore, these liquids need to be replenished and renewed in a timely manner, but at present there are no measuring instruments that can easily determine the degree of contamination deterioration of these liquids at the site, and at the factory site, such as the present invention, water quality that is compatible with the field. There is a high demand for judging devices.

It is a block diagram of the measuring device by this invention. It is sectional drawing of a sensor electrode. It is a top view of a sensor electrode. FIG. 3 is a structural diagram of a measuring cup. These are measured values for purified water, tap water, and natural water. It is the relationship between the concentration of ascorbic acid and the sensor reading. This is the relationship between the detergent concentration and the sensor reading. It is the relationship between the density | concentration of commercially available milk, and a sensor indication value. It is the relationship between the density | concentration of milk powder and a sensor indication value. It is a measured value of a nearby aqueous solution.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Sensor electrode 2 Sensor electrode holder 3 Connection cable 4 Detection part 5 Display part 6 Power supply 7 Conductor board 8 Insulation board 9 Insulation film 10 Lead conducting wire 11 Inner cup 12 Outer cup

Claims (2)

    Capacitor-type electrode pairs in which an insulating plate is inserted and the outer surfaces of the electrode plates adhered and fixed to each other are covered with an insulating film are used as sensors. When this sensor electrode is immersed in water (solution, suspension), Due to the difference in properties, the capacitance induced in the sensor electrode changes. This capacitance can be measured to determine the degree of change in water quality. Based on such experimental facts, a measuring method and a measuring instrument for determining deterioration / contamination level of water, concentration of aqueous solution, etc., characterized by using a sensor electrode having the above structure.     When a highly polar substance is contained in the measurement aqueous solution, it strongly adsorbs on the sensor surface, and its influence appears in the subsequent measurement. In this case, it is necessary to update the sensor electrode. Therefore, it is a disposable sensor electrode that is easily removable.

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