Classifications

• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
  • G01R27/00—Arrangements for measuring resistance, reactance, impedance, or electric characteristics derived therefrom
  • G01R27/02—Measuring real or complex resistance, reactance, impedance, or other two-pole characteristics derived therefrom, e.g. time constant
  • G01R27/26—Measuring inductance or capacitance; Measuring quality factor, e.g. by using the resonance method; Measuring loss factor; Measuring dielectric constants ; Measuring impedance or related variables
  • G01R27/2617—Measuring dielectric properties, e.g. constants
  • G01R27/2635—Sample holders, electrodes or excitation arrangements, e.g. sensors or measuring cells
  • G01R27/2676—Probes

Definitions

• the present invention relates to a liquid concentration meter, particularly to a concentration meter for measuring the concentration of an aqueous electrolyte solution containing ions.
• aqueous solutions of electrolytes such as caustic soda Na ⁇ and hydrochloric acid are used for chemical treatment and cleaning. Is used. These electrolyte aqueous solutions are required to have a relatively high concentration of 0.1 wt% to several wt% or several tens wt%, and have a strong chemical reaction of acids, alkalis, etc. There are many things that need to be handled with care, such as danger, and it is also necessary to supply a specified concentration at such a high concentration over a long period of time, as in a mass production factory. I have.
• the densitometer therefor there is a conductivity meter at concentrations ranging from ppm order to about LWT%, conductivity meter, no current flows polarization with a concentration of over about 1 1% or 4 is generated From that, on
• an electromagnetic concentration meter is used. Used.
• An electromagnetic densitometer measures conductivity by immersing a transformer consisting of two superimposed annular coils for transmission and detection in a sample solution and using the electromagnetic induction current flowing in the solution passing through the through-hole.
• concentration measurement range is up to several tens of Wt%, and online concentration measurement is possible, there is a problem that it is large, unwieldy, and expensive. .
• An object of the present invention is to provide an inexpensive densitometer that is capable of on-line concentration measurement, and that is small, easy to handle, and inexpensive to solve the above-mentioned problems of the prior art. . Disclosure of the invention
• a coil and a high-frequency oscillation circuit including the coil as an oscillating element are mounted on a detection end of a concentration detector immersed in a sample solution which is an aqueous electrolyte solution, and the detector is provided in the sample solution. It is configured to measure the concentration of the sample liquid by detecting a change in the oscillation state of the high-frequency oscillation circuit when immersed in the sample.
• the concentration meter according to the present invention is configured such that the coil is formed in a flat spiral shape, and is integrated with a high-frequency oscillation circuit by a resin to form a detection end of a concentration detector immersed in a sample solution.
• the flat spiral coil is placed parallel to the end face of the detection end of the concentration detector immersed in the sample liquid, or the detection end of the concentration detector immersed in the sample liquid. It is arranged so as to protrude vertically from the end face. Further, the flat spiral coil is formed by being densely wound or coarsely wound depending on the purpose of use.
• the concentration meter Since the concentration meter according to the present invention is configured as described above, if the detection end is immersed in the aqueous electrolyte solution to be measured, the conductive aqueous electrolyte solution is electromagnetically coupled to the coil and the detector is connected to the detector. Oscillation circuit inside Since this influences the oscillation conditions, the current supplied to the oscillation circuit changes according to the conductivity of the aqueous electrolyte solution and thus the concentration. Since the electrolyte aqueous solution around the detection end is considered to affect the volume, the detector is immersed to a predetermined depth, and the liquid exists within a predetermined distance around the detection end. If the conductor such as metal is kept away from the range, the influence of the aqueous electrolyte solution on the oscillation conditions of the oscillation circuit is stabilized, and the accuracy of the concentration measurement can be improved.
• the coil in a flat spiral shape and arranging it at the detection end, the facing area between the coil and the sample solution increases, and high-accuracy concentration measurement becomes possible. Even if the coil is formed in a ring shape, the same operation and effect as those of a flat spiral coil can be achieved.
• FIG. 1 is a schematic configuration diagram showing an appearance of an embodiment of a densitometer according to the present invention.
• FIG. 2 is a block diagram showing a circuit configuration of a signal processing circuit for density detection in an embodiment of the densitometer according to the present invention.
• FIG. 3 is a conceptual structure diagram showing a structure of a sensor according to the embodiment of the present invention.
• FIGS. 4A and 4B are an internal structural view and an external perspective view, respectively, showing an enlarged tip portion for illustrating the configuration of another embodiment of the sensor in the densitometer according to the present invention.
• FIGS. 5A and 5B are an internal structure diagram and an external perspective view, respectively, showing an enlarged tip portion for illustrating the configuration of still another embodiment of the sensor in the densitometer according to the present invention.
• FIG. 4 is an explanatory diagram for explaining a winding state of a sensor oscillation coil in the concentration meter according to the present invention.
• 7A and 7B are explanatory diagrams each showing a modified example of the sensor oscillation coil in the concentration meter according to the present invention.
• FIGS. 8A and 8B are perspective views showing a modification of the sensor according to the embodiment of the present invention.
• FIG. 9 is a perspective view showing a modification of the pointing / adjusting unit.
• 10A to 10E are characteristic diagrams showing measurement examples using the densitometer of the present invention.
• FIG. 1 is a schematic configuration diagram showing the appearance of a densitometer according to an embodiment of the present invention.
• 1 is a meter
• 2 is a power lamp
• 3 is a power switch
• 4 is a span volume
• 5 is a zero-adjustment volume
• 6 is a sensor as a concentration detector
• 7 is a lead wire
• 8 is a measurement.
• the aqueous electrolyte solution to be used such as hydrochloric acid or cassette.
• the zero point is adjusted using the zero adjustment volume 5 in the air.
• the sensor 6 is immersed or pressed against a standard solution having a standard conductivity or a calibration plate, and span adjustment is performed using a span volume unit 4.
• the sensor 6 is immersed in the electrolyte aqueous solution 8 at a depth of, for example, 4 O mm or more, and the liquid exists within a range of, for example, 30 to 40 mm around the tip thereof, and Dip so that a conductor such as metal does not come close to the area.
• FIG. 2 is a block diagram showing a circuit configuration of a signal processing circuit for density detection in the present embodiment, where 11 denotes, for example, several MHz to several tens of MHz.
• An oscillation circuit having an oscillation frequency on the order of z, 12 is a coil, which is a circuit element of the oscillation circuit, is disposed inside the tip of the sensor 6, and 13 and 13 'are for power supply.
• a lead line for transmitting a measurement signal, 14 is a detection circuit for detecting the oscillation state of the oscillation circuit 11, 15 is a comparison circuit for comparing the detected voltage signal with the reference voltage ref, 1
• FIG. 6 is a stabilized DC power supply that supplies a DC power supply to the detection circuit 14 and a reference voltage to the comparison circuit 15, and 17 is a zero-adjustment volume for adjusting the reference voltage to perform zero adjustment (Fig. 1 5) and 18 are span volumes (4 in Fig. 1) for adjusting the signal level of the comparison result to perform span adjustment, 19 is a DC amplifier, and 20 is for displaying the measurement results. It's a night.
• the detection circuit 14 Is done.
• the detection voltage is, for example, a comparison circuit composed of a differential amplifier.
• the circuit form of the oscillation circuit 11 is from several MHz to several tens M As long as oscillation at a high frequency of Hz is possible, any type such as a Colpitts type or a tray type may be used, and the temperature of the electrolyte aqueous solution 8 to be measured is not only room temperature but also 100%. Some of them reach several tens of degrees, and it is necessary to perform temperature compensation to ensure the measurement accuracy. Therefore, the oscillation circuit 11 is well known to other circuits as well. Temperature compensation circuit is attached.
• FIG. 3 is a conceptual structural diagram showing a configuration of one embodiment of the sensor 6 in the concentration meter according to the present invention.
• Reference numeral 61 denotes, for example, a cylindrical body of vinyl chloride, and an oscillation circuit 11 is housed at the tip, that is, at the detection end, so that the oscillation coil 12 is located at the tip of the cylinder.
• Numeral 62 denotes a liquid-contacting part made of a front plate of vinyl chloride of the same material adhered to the tip of the cylindrical body 61, so that the inside of the cylindrical body 61 is sealed at least in a liquid-tight manner. It is sealed.
• 63 is a cable fixing device for fixing a shielded wire, and 64 is a shielded wire.
• the cylindrical body 61 has a diameter of about 20 to 40 O mm and a length of 200 to 100 O mm, and the tip is immersed in an aqueous electrolyte solution 8 to be measured.
• the rear end is gripped by the operator or attached to a holder for continuous measurement.
• the lead wires 13 and 13 ′ are formed by a shield wire that is continuous with the shield wire 64, and are fixed to the rear end of the sensor 6 by the cable fixture 63, and Even if an external force is applied to the wire 6 4, it is prevented from affecting the inside.
• the oscillation circuit 11 A temperature sensor is provided in close proximity to the sensor, and its detection output is taken out via a shielded wire 64 and transmitted to the comparison circuit 15 to increase the measurement accuracy by adjusting the concentration value to compensate. be able to.
• the oscillation circuit 11 is made of, for example, a compact printed circuit or an integrated circuit, and is further strengthened by being molded into the cylindrical body 61 with epoxy casting resin or the like.
• the oscillation coil 12 may have any shape and structure as long as the coil 12 can be electromagnetically coupled to the electrolyte aqueous solution 8 to be measured.
• FIGS. 4A and 4B are an internal structural view and an external perspective view, respectively, showing an enlarged tip portion for illustrating the configuration of another embodiment of the sensor 6 in the densitometer according to the present invention.
• 1 1 ′ and 1 2 ′ are an oscillation circuit and a coil equivalent to the oscillation circuit 11 and the coil 12 constituting the detection end in FIGS. 2 and 3, respectively.
• the oscillating circuit 11 ' is composed of, for example, a compact printed circuit board or an integrated circuit in the form of a flat plate, and the coil 12' is, for example, a flat spiral having an outermost diameter of about 10 to 3 O mm. As shown in FIG.
• the coil is formed at one end of the plate-like oscillation circuit 11 ′, in parallel with the edge thereof, and with respect to the plate surface of the oscillation circuit 11 ′. They are joined with orthogonal directions.
• the oscillation circuit 11 ′ and the coil 12 ′ are molded and integrated with an epoxy casting resin 65 or the like to constitute a detection end of the sensor 6.
• the flat spiral coil 12 ′ is disposed so as to face the surface of the liquid contact portion 62 of the sensor 6.
• the sensor 6 of the present embodiment configured as described above has a wide area and a very close proximity between the oscillation coil 12 ′ and the sample solution which is the aqueous electrolyte solution 8 (FIG. 1) to be measured. Since they face each other, the electromagnetic coupling between them is good, and the accuracy of the concentration measurement is therefore high. Can be increased.
• FIGS. 5A and 5B are an internal structural view and an external perspective view, respectively, showing an enlarged tip portion for showing the configuration of still another embodiment of the sensor 6 in the densitometer according to the present invention.
• reference numerals 1 1 "and 1 2" denote oscillation circuits and coils equivalent to the oscillation circuit 11 and the coil 12 constituting the detection end in FIGS. 2 and 3, respectively.
• the oscillating circuit 11 is formed, for example, in a flat plate shape from a compact printed circuit or an integrated circuit
• the coil 12 is formed, for example, from 10 to 10 mm in outermost diameter. It is formed into a flat spiral coil of about 3 Omm, and as shown in Fig.
• the oscillation circuit 11 "and the coil 12" are molded by epoxy casting resin 6 or the like to form the detection end of the sensor 6 as shown in Fig. 5B.
• the plate-shaped spiral coil 12 " is molded and integrated so as to protrude from the end face of the cylindrical sensor 6, thereby forming a liquid contact part 6 2 '.
• the sample solution is the electrolyte solution to be measured 8 ( (Fig. 1) is present and faces the aqueous electrolyte solution 8 in a wider area and closer to those of the other embodiments described above. Is further improved, so that a more accurate concentration measurement can be performed.
• the flat spiral coil 12 or 12 "shown in FIGS. 4A and 5A described above is formed by spirally winding a single conductive wire. It can also be formed by printing and wiring on a printed board using technology. Alternatively, for 1-2 ", a flat plate is preferable, and a plate with a distorted surface distorts the oscillation waveform to generate harmonics, which causes a reduction in detection sensitivity.
• FIGS. 6A and 6B are explanatory diagrams for explaining the winding mode of the flat spiral coil 12 ′ or 12 ′′ shown in FIG. 4A or 5A, respectively.
• spiral coil windings There are two types of spiral coil windings, as shown in FIG. 6A and densely wound as shown in FIG. 6A and coarsely wound as shown in FIG. 6B.
• the capacitance component that determines the oscillation frequency is determined by the oscillation circuit 1 1 ′ (1 1 )
• the positional relationship between it and the oscillating coil 12 '(1 2 ") are greatly restricted, and in practice, it cannot be reduced below a certain range. However, there are circumstances in which they can only have a limited range of values.
• FIGS. 7A and 7B show a sensor for a densitometer according to the present invention. It is explanatory drawing which shows the modification of a vibration coil.
• the coil of this modification is formed in a ring shape, and the ring-shaped coil portion can be formed in a flat plate shape (FIG. 7A) or a tubular shape (FIG. 7B).
• the coil of this example is equivalent to or more than the roughly wound coil shown in Fig. 6B. It has the advantage of high detection sensitivity and easy coil fabrication.
• the cylindrical body 61 and the liquid contact part 62 are formed, for example, by molding and covering or surrounding with vinyl chloride, epoxy resin, or the like.
• a more heat-resistant material can be used.
• the structure of the rear end of the sensor 6 is shown in a cylindrical shape (Fig. 1).
• deformations are required, for example, as shown in Figures 8A and 8B.
• the structure used for measurement attached to the side is shown, and a flange 68 is provided at the rear of the sensor 6 to seal the inside of the tank and also support the sensor itself.
• B in the middle of the piping
• the structure used to measure the concentration of the sample solution flowing in the pipe is shown.
• a screw portion 69 is formed by attaching a screw.
• FIG. Fig. 9 shows a case where a meter 1 and adjustment knobs 45 are arranged, but as shown in Fig. 9, it is intended to be attached to a control panel in an operation control room or the like in the manufacturing process. :.
• the front panel 10 of the measuring instrument box 9 is formed in a shape that protrudes in a flange shape, and the front panel 10 is provided with an integral mounting member.Instruction on the control panel surface
• the structure can be as follows.
• FIGS. 10A to 10E are characteristic diagrams showing measurement examples using the densitometer of the present invention.
• Fig. 1 OA shows the results of a wide range of measurements for various aqueous electrolyte solutions, and the maximum point appears in the middle concentration range for most of the sample solutions. It is shown that each of the sample liquids has a characteristic that monotonically increases in the range of 0 to 10 several wt%.
• Fig. 10B Fig. 10C, Fig. 10D and Fig. 10E show the characteristics of NaC1, HC1, ZnC12 and NaOH in the dilute concentration range, respectively. Is enlarged. Industrial applicability
• the present invention a compact, inexpensive densitometer capable of online measurement can be obtained.
• the metal electrode is not exposed at the detection end, and
• it since there is no through hole in the measurement part like an electromagnetic densitometer, it has a very simple shape and is easy to handle.

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• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Investigating Or Analyzing Materials By The Use Of Electric Means (AREA)
• Investigating Or Analyzing Materials By The Use Of Magnetic Means (AREA)

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Cited By (2)

Citations (3)

• 1993
  • 1993-12-14 TW TW82110565A patent/TW295621B/zh active
  • 1993-12-15 AU AU57145/94A patent/AU5714594A/en not_active Abandoned
  • 1993-12-15 WO PCT/JP1993/001816 patent/WO1994014056A1/ja active Application Filing

Patent Citations (3)

Non-Patent Citations (1)

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