JPH01297519A - Liquid thermometer - Google Patents

Abstract

PURPOSE:To execute the measurement with high sensitivity by immersing a photoconductive body into an enclosed container, filling the inside of the enclosed container with a liquid and detecting a temperature variation of the outside of the container as an output variation of a photodetector by a refractive index variation of the liquid in the container. CONSTITUTION:A plate 11 to which an incident light part 10a of a photoconductive medium 10 and a light receiving part 10b are fixed is joined with a screw to a flange part 12a of a container 12 through an elastic member 13. In this plate 11, a hole 14 is pierced in advance, and from this hole 14, a reference liquid 15 is injected into the container 12, and after the container 12 is filled entirely with the liquid 15, the hole 14 is closed up tightly by a blank plug. In this case, as for the liquid 15, a water solution which is not deteriorated in a room temperature area, has photoabsorption sensitivity against incident light wavelength, and in which a substance of a wavelength area is dissolved is used. In such a state, a temperature variation of the outside of the container is detected as an output variation of a photodetector 22 by a refractive index variation of the liquid 15 in the container. In such a way, the measurement can be executed with high sensitivity.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a liquid thermometer, more particularly to measuring the temperature of a reaction solution, and particularly to a device for controlling the temperature of a reaction solution in an industrial plant.

Liangrai 1st Ward Conventionally, liquid-filled glass thermometers, thermocouple thermometers, resistance thermometers, crystal resonator thermometers, etc. have been used to measure temperature in the normal temperature range (5° C. to 40° C.).

In addition, acidic solutions, alkaline solutions, barred solvents, and the like are generally used as reaction solutions in industrial plants, and highly accurate liquid temperature control in the room temperature range is required for these liquids.

When using a conventional thermometer to control the temperature of the liquid mentioned above, for example, a thermometer made of liquid-filled glass cannot be automatically measured;
It has the disadvantage that it cannot be used in hydrofluoric acid, and since the thermometer is made of metal, it has the disadvantage of being corroded by acid and alkaline solutions. Also, since resistance thermometers require a current to flow through them, there are explosion-proof problems with organic solvents.
Quartz crystal thermometers could not operate in liquids.

Furthermore, the present applicant previously proposed a liquid concentration meter as shown in FIG. This seepage is known as an evanescent wave (part A).

If the wavelength of the light is the absorption wavelength of the solid content (for example, dye) contained in the liquid, this seeped light will be absorbed by the dissolved substance. Therefore, the amount of light propagating within the fiber 1 depends on the substance concentration, and the substance concentration can be determined by detecting the fiber output light amount. Further, as shown in FIG. 9, when the refractive index of the liquid changes, the reflection angle 0 of the fiber propagating light shown in FIG. 8 changes, and the amount of propagating light changes.

Furthermore, as shown in FIG. 10, the refractive index of the liquid has temperature dependence. Namely, 1. Usually, as the temperature increases, the liquid density decreases, and therefore the liquid refractive index decreases. Therefore, when the liquid temperature changes, the liquid refractive index changes and the amount of light propagating through the fiber changes. Conversely, the liquid temperature can be determined by detecting the amount of fiber output light. The present invention is constructed using such a principle.

l-Part of the present invention was made in view of the above-mentioned circumstances,
Especially acidic and alkaline corrosive solutions.

The purpose of this invention is to provide a thermometer that has excellent wave resistance, explosion resistance, and high sensitivity for solutions containing flammable organic solvents.

In order to achieve the above object, the present invention provides a photoconductive medium having a curvature such that one end is in contact with an incident light source and the other end is in contact with a light receiving element, and a sealed container in which the photoconductive medium is immersed. , the sealed container is fully filled with liquid, and a temperature change outside the container is detected as a change in the refractive index of the liquid in the container or a change in the output of the light receiving element due to a change in the refractive index and absorption coefficient of the liquid in the container. It is characterized by this. Hereinafter, the present invention will be explained based on examples.

FIG. 1 is a partial perspective view for explaining one embodiment of the present invention, and FIG. 2 is a cross-sectional configuration diagram.

Reference numeral 10 denotes a photoconductive medium having a curvature having an incident light part 10a and a light receiving part 10b, 11 a flat plate to which the photoconductive medium is bonded and fixed with an adhesive or the like, and 12 a container in which the photoconductive medium is immersed, with a flange part 12a. have. The photoconductive medium 1
A flat plate 1 on which the incident light section 10a and the light receiving section 10b of 0 are fixed.
1 connects the flange portion 12 of the container 12 via the elastic member 13
It is connected to a by screws or the like. A hole 14 is pre-drilled in the flat plate 11, and a reference liquid 15 is injected into the container 12 through the hole 14, and the container 12 is filled with the reference liquid 1.
After filling up with step 5, it is sealed with a blind stopper 16. Incidentally, the elastic member 13 is caused by the reference liquid 15 due to an increase in the environmental temperature.
20 is a flat plate having a light emitting element 21 and a light receiving element 22 fixed to the flat plate 11 in correspondence with the incident light part 10a and the light receiving part 10b of the photoconductive medium 1°. It is fixed to the flat plate 11 via a sealing member such as an O-ring 23.

FIG. 3 is a cross-sectional configuration diagram for explaining another embodiment of the present invention. The same reference numbers are given. Therefore, in the case of this embodiment, the flat plate 20 includes:
Optical fibers 24 and 25 connected to a distant light source and a light receiving element (not shown) are fixed corresponding to the incident light part 10a and the light receiving part 10b of the photoconductive medium 1o fixed to the flat plate 11. Similar to the embodiment shown in FIGS. 1 and 2, it is fixed to the flat plate 11 via a sealing member such as an O-ring 23. Therefore, this embodiment is especially excellent in explosion-proof properties since it does not include any electrical circuits.

As the reference liquid 15, an aqueous solution is used in which a substance that does not deteriorate at room temperature and has a wavelength band having light absorption sensitivity to the wavelength of incident light is dissolved.

The reason for this is to prevent light leaking from the photoconductive medium from being reflected within the container and returning to the photoconductive medium,
Alternatively, if the container is transparent, this is to remove disturbance light such as light incident from outside the container. The closer the refractive index of the aqueous solution is to the refractive index of the photoconductive medium, the better the sensitivity to changes in the refractive index of the aqueous solution will be, but the amount of propagated light will be reduced.

FIG. 4 is a diagram showing relative power to liquid refractive index. The refractive index of the photoconductive medium (fiber) is 1°457, and in the region where the liquid refractive index is 1.43 or more, the amount of output change with respect to the change in refractive index increases.

However, when it becomes 1.455 or more, the output value becomes small,
S/N deteriorates. From this experimental result, we can determine that the liquid refractive index is N
Letting NF be the refractive index of a photoconductive medium, it can be seen that Np -0,04<NL<NF O,01 is desirable. In other words, the region A in FIG. 4 has high sensitivity to refractive index fluctuations and has sufficient output.

Note that the refractive index indicates a value of No''.

Further, as the container 12, polyethylene, polypropylene, tetrafluoroethylene polymer (PTFE), a copolymer of tetrafluoroethylene and hexafluoropropylene (F E
A resin molded product containing a large amount of methyl groups and perfluoroalkyl groups such as P) is used.

Furthermore, if a member whose metal surface is coated with these resins is used, it will have excellent liquid resistance even if the liquid to be tested is acidic or alkaline. Furthermore, if the liquid to be tested contains an organic solvent, the liquid resistance will be good if glass or metal is used as the container 12. The substance dissolved in the reference liquid 15 is preferably one that ionizes in solution, such as transition metals and dyes. Furthermore.

By thinning the wall thickness of the container 12 and reducing its capacity to reduce the amount of reference solution, responsiveness to changes in liquid temperature can be improved.If a container whose metal is coated with resin is used, responsiveness can be improved. can be increased.

The material of the photoconductive medium is preferably glass or resin, and the shape may be a U-shape, a hemisphere, or a spheroid.

Below, an example will be shown in which an aqueous alcohol solution containing HCQ as a catalyst was used as the reaction solution in the production of ultrafine particles by the metal alkylate method, and the solution was used when the reaction was carried out while controlling the liquid temperature.

1-Suitable photoconductive medium: Molded product of polymethylpentene (trade name TPX, Mitsui Toatsu Chemical, refractive index No. = 1.463), cross section 1 m x 1 m corner, length ioms 1 radius of curvature 5 ■ Flat plate: Polypropylene adhesive for photoconductive medium to flat plate: XB5052, Ciba Geigy Container: Polypropylene (depth 13I, cross section 81B
l, 5 m, inner thickness 0.3 mm) Reference liquid: Dissolved substance... Phthalocyanine blue〇, 5 wt% Refractive index -1'Jo = 1.433 Light source H56Qnm wavelength LED Light receiving element: Si photodiode light source, light receiving element was coupled with a photoconductive medium through an optical fiber.

As shown in FIG. 5, the output value of the aqueous alcohol solution containing HCQ with respect to the liquid temperature shows that the output changes by 10% for a change in liquid temperature of 0.1° C., indicating that it has sufficient sensitivity. In addition, the container 12 has excellent acid resistance and is resistant to flammable alcohol solutions since the light source, light receiving element, and photoconductive medium are connected using optical fibers.

This made it possible to create an explosion-proof thermometer.

Furthermore, when a substance whose absorption coefficient depends on temperature is used as the substance dissolved in the reference liquid 15, the amount of light propagating within the photoconductive medium changes depending on the temperature. At this time, if a material whose absorption coefficient decreases as the temperature rises is used, as shown in Figure 6, the amount of light increases as the temperature rises, and as mentioned earlier, the refractive index also decreases. It is also possible to measure with higher sensitivity. Next, as a dissolved substance in the reference liquid 15 in the container 12, BiV4.
0. An example using lCaO will be shown.

EXAMPLE An example will be shown in which an aqueous alcohol solution containing HCQ as a catalyst was used as the reaction solution in the production of ultrafine particles by the metal alkylate method, and the reaction was carried out while controlling the temperature of the solution.

Photoconductive medium: Molded product of polymethylpentene (trade name TPX, Mitsui Toatsu Chemical, refractive index 1'Jo = 1.463), cross section 11 m x 1 + nm corner, length 10 mm, radius of curvature m Flat plate: Polypropylene light Adhesive material for conducting medium to flat plate: XB5052, Ciba Geigy Container: Made of polypropylene, depth 1.3 rrn, cross section 8 nu x 1, 5 m + inner thickness 0.3 m Reference liquid:
Dissolved material trade...B x V 04・0.1. Ca02w
t% Refractive index: ND=1.433 Light source: White light source with a 530 nm filter Light receiving element: Si photodiode The light source and the light receiving element were coupled to a photoconductive medium through an optical fiber. Further, the spectral characteristics of V and O5 are shown in FIG.

Effects As is clear from the above explanation, according to the present invention, the parts estimate cost can be reduced because it is made of inexpensive materials.

[Brief explanation of the drawing]

FIG. 1 is a partial perspective view for explaining one embodiment of the present invention, FIG. 2 is a cross-sectional configuration diagram, and FIG. 3 is a cross-sectional configuration diagram for explaining another embodiment of the present invention. Figure 4 is a diagram showing the rate of change of liquid refractive index and relative output, Figure 5 is a diagram showing the temperature of the test liquid and rate of change of relative output, and Figure 6 is a diagram showing the reference liquid temperature and relative output. FIG. 7 is a diagram showing the spectral characteristics of V and Ol, FIG. 8 is a diagram showing the principle of the present invention,
FIG. 9 is a diagram showing the refractive index of the liquid and the rate of change in relative direction;
FIG. 10 is a diagram showing the liquid temperature and the rate of change of the liquid refractive index. 10... Photoconductive medium, 10a... Incident light section, 10b
... Light receiving part, 11 ... Flat plate, 12 ... Container, 13
... elastic member, 14 ... hole, 15 ... reference liquid,
2o... Flat plate, 21... Light emitting element, 22... Light receiving element, 24.25... Optical fiber.

Claims (1)

[Scope of Claims] 1. A photoconductive medium having a curvature such that one end is in contact with an incident light source and the other end is in contact with a light-receiving element, a closed container in which the photoconductor is immersed, and the closed container is full. 1. A liquid thermometer, characterized in that the temperature change outside the container is detected as a change in the output of a light-receiving element due to a change in the refractive index of the liquid inside the container. 2. A photoconductive medium with a curvature such that one end is in contact with the incident light source and the other end is in contact with the light receiving element, a sealed container in which the photoconductive medium is immersed, and a liquid filled in the sealed container. 1. A liquid thermometer, which detects a temperature change outside the container as a change in the output of a light-receiving element due to a change in the refractive index and absorption coefficient of the liquid inside the container. 3. The refractive index of the photoconductive medium and the liquid in the container is N_F, N
3. The liquid thermometer according to claim 1, wherein the liquid refractive index is within the range of N_F-0.04≦N_L≦N_F-0.01, where _L.