JPH06138025A - Method for measuring mixed ratio of object to be measured and its device - Google Patents

Abstract

PURPOSE:To provide a method for measuring a mixed ratio of an object to be measured and its device capable of measuring the mixed ratio of at least a substance in the case where exact measurement is made possible at a low cost, for instance, an optical branching device such as an optical coupler is utilized and a plurality of substances are mixed, particularly, in the case where their temperature is unstable. CONSTITUTION:A branching ratio is measured with an optical branching device 10, at the time the temperature of an object to be measured is measured with a thermocouple 60, its signal is transmitted to a mixed ratio calculation device 200 through a temperature measurment device 62. In the mixed calculation device 200 a mixed ratio of an oil part in an object to be measured obtained from a branching ratio obtained with the optical branching device 10 is compared with the known temperature coefficient of the branching ratio of the optical branching device 10 on the basis of a measured result of the temperature obtained with the thermocouple 60, corrected, thereby and a quantity of oil is calculated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention utilizes an optical branching device such as an optical fiber coupler to measure the mixing ratio of at least one substance when a plurality of substances are mixed. The present invention relates to a method and an apparatus for measuring a mixing ratio of a substance to be measured, and in particular, in the case where a plurality of substances are mixed, as in the case of measuring the amount of oil in a wax during a petroleum refining process, The present invention relates to a mixing ratio measuring method and device for measuring a mixing ratio of substances when the temperature is unstable. Further, the present invention can be used even when there is a danger of explosion due to fire, such as the case where the environment to be measured uses an organic solvent, a method for measuring the mixing ratio of an object to be measured having an explosion-proof characteristic. And the device.

[0002]

2. Description of the Related Art Conventionally, for example, in order to measure the amount of oil in a wax, a certain amount of a sample is dissolved in a certain amount of a solvent, methyl ethyl ketone, and then, as specified in JIS K2235, A very complicated process of cooling the temperature to −32 ° C., filtering the deposited wax, finally evaporating the solvent in the filtrate to measure the amount of residual oil, and calculating the amount of oil was required.

On the other hand, the inventors of the present invention have disclosed in Japanese Unexamined Patent Publication No. 4-1.
As described in Japanese Patent No. 34250, a method and a device for measuring a mixing ratio of an object to be measured, which can measure the amount of oil in a simple and instantaneous manner, have been proposed. The method and apparatus will be briefly described with reference to FIG.

The object mixing ratio measuring device 1 has an optical branching device 10 such as an optical fiber coupler. The optical branching device 10 is attached to a housing 14 preferably made of silica, which is the same material as the optical fiber, and a measuring probe 20 is configured. The sample S, which is the object to be measured, that is, wax at a temperature of, for example, about 40 ° C., which is maintained in a fluid state, is injected into the housing 14 through the upper opening, whereby at least the optical coupling portion 12 of the optical branching device 10. The outer circumference of is covered with the object to be measured S.

In this state, when the signal light (light intensity P ₀ ) is incident on the first optical fiber f ₁ by the light emitting device 30 such as a light emitting diode which emits light of the wavelength (λ ₁ ), In the optical coupling part 12, a part or all of the signal light moves to the second optical fiber f ₂ depending on the optical refractive index of the substance existing around the optical coupling part 12. From the output ports of the first and / or second optical fibers f ₁ and f ₂ , the light intensity P
Emit at ₁ and P ₂ .

The first and / or the second optical fiber f ₁ ,
The light emitted from the output port of f ₂ is arranged corresponding to the output ports of the first and second optical fibers f ₁ and f ₂ ,
The light is received by light receivers 31 and 32 such as photodiodes. The signals obtained by the light receivers 31 and 32 are transmitted to signal processing means (not shown), and the branching ratio is calculated by the signal processing means.

There is a correlation between the amount of oil in the wax and the optical refractive index, and the branching ratio of the optical branching device 10 depends on the optical refractive index of the substance existing around the optical coupling portion 12. Depends on.

Therefore, according to this method, when the intensity of the light from the light emitter 30 is kept constant, the difference in the mixing ratio of the measured objects flowed to the measuring probe 20 to cover the optical coupling portion 12. That is, that is, the branching ratio becomes a different value due to the difference in the mixing amount of the oil component in the wax.

The signal processing means is input with the wavelength branching characteristic of the measuring probe 20 with respect to the known amount of oil in the wax, and this wavelength branching characteristic and the unknown measured object are input to the optical branching device 10. The branching ratio obtained in the case of introduction is compared, and the mixing ratio of oil in the measured object is obtained.

As described above, according to the method for measuring the mixing ratio of the objects to be measured, the optical branching device 1 such as an optical fiber coupler is used.
0 is used to bring the object S to be measured into contact with the optical coupling portion 12 of the optical branching device 10, the branching ratio in one wavelength region at that time is measured, and the measurement result is known to the known optical branching device 10. By comparing with the branching characteristics, the mixing ratio of at least one substance when a plurality of substances are mixed can be measured.

This measuring object mixing ratio measuring method and apparatus are
Since the optical fiber coupler forming the optical branching device 10 is a dielectric material, it has an explosion-proof property, and is extremely effective for use during a petroleum refining process.

[0012]

However, this measuring system substantially measures the optical refractive index of the object to be measured, and since the refractive index of the substance depends on the temperature, the optical branching is performed. The branching characteristic of the container 10 depends on the temperature, as shown in FIG. Therefore, when the temperature of the object to be measured cannot be kept constant, the measurement result includes a large error, which has a drawback that the practicality is reduced.

In order to keep the temperature of the object under measurement constant, FIG.
As shown in Figure 2, it may be possible to install ancillary equipment to keep the temperature constant. That is, the measurement probe 20 including the optical branching device 10 is surrounded, a housing 50 is further provided, the heat medium 52 is accommodated in a space defined between the measurement probe 20 and the housing 50, and This heat medium 5
The temperature of 2 is measured by the temperature measuring means 54, and the cooling means 56
By controlling the heating means 58 with the temperature control means 60, the temperature of the object to be measured S is maintained at a constant temperature. However, in this method, there is a problem that the device is complicated, the size is increased, and the cost is increased.

Accordingly, it is an object of the present invention, especially when a plurality of substances are mixed, which utilizes an optical branching device such as an optical fiber coupler, which enables accurate measurement at low cost, It is an object of the present invention to provide a method and an apparatus for measuring a mixing ratio of an object to be measured, which can measure the mixing ratio of at least one substance when the temperature of the substance is unstable.

Still another object of the present invention is to provide a method for measuring the mixing ratio of an object to be measured, which has a simple structure and does not require any auxiliary equipment for keeping the object to be measured at a constant temperature while maintaining the explosion-proof function. And to provide a device.

[0016]

The above objects are achieved by the method and apparatus for measuring the mixing ratio of an object to be measured according to the present invention.
In summary, the present invention is to contact an object to be measured with an optical coupling part of an optical branching device, measure a branching ratio at that time, and compare the measurement result with a known branching ratio characteristic of the optical branching device. According to the method of measuring the mixing ratio of the measured object, the temperature of the measured object is measured, and the measured mixing ratio of the measured object is compared with the known temperature characteristic of the optical branching device with respect to the measured object. A method for measuring a mixture ratio of an object to be measured, the method comprising:

Such a measuring method includes a light emitting device that emits light,
An optical branching device composed of an optical waveguide having an optical coupling part,
A means for surrounding at least the optical coupling part of the optical branching device, a means for contacting an object to be measured with the optical coupling part, a light receiver for detecting the light branched by the optical branching device, and an object to be measured. A temperature measuring means for measuring a temperature and a signal obtained by the light receiver are processed to calculate a branching ratio, a temperature signal from the temperature measuring means is processed to calculate a temperature, and this value is calculated as It is preferably carried out in a mixing ratio measuring device for a measured object characterized by having a signal processing means for obtaining a mixing ratio of the measured object by comparing with a known temperature branching ratio characteristic of a branching device. obtain.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The method and apparatus for measuring the mixing ratio of the object to be measured according to the present invention will be described below in more detail with reference to the drawings.

Referring to FIG. 1, there is shown a schematic configuration of an apparatus for carrying out the method for measuring a mixing ratio of an object to be measured according to the present invention. In the present embodiment, the description will be made assuming that the mixing ratio of the oil component in the wax is measured, but the present invention is not limited to this.

In this embodiment, the device 1 for measuring the mixing ratio of the object to be measured is used.
Has the same configuration as the device for measuring a mixing ratio of the object to be measured described with reference to FIG. 4, except that the measuring probe 20 is provided with temperature measuring means for measuring the temperature of the object to be measured S, such as a thermocouple 60 and The difference is that a temperature measurement unit 62 is provided. The temperature measuring means will be described later. or,
The optical branching device 10 may use a planar waveguide as a waveguide, but in this embodiment, a case of an optical fiber coupler using a generally used optical fiber will be described.

The optical branching device 10 is manufactured by using the _two optical fibers f ₁ and f ₂ by the stretch fusion method known to those skilled in the art. In this embodiment, the first and second optical fibers f ₁ and f
_Two shall be the same and a single mode fiber shall be used. That is, in the present embodiment, the two, namely, the first
And the second optical fibers f ₁ and f ₂ both have a core diameter of 5 to 10 μm and a clad diameter of 100 to 150 μm.
Is a single mode optical fiber having a cutoff wavelength of 1200 nm or less, and the optical coupling part 12 is pulled while heating these optical fibers f ₁ and f ₂ together to about 1500 ° C.
Has a diameter of 6 μm, and the length of the optical coupling portion 12 is about 60 m.
An optical branching device 10 having a length of m was manufactured.

The optical branching device 10 is attached to, for example, a housing 14 made of silica, which is preferably the same material as the optical fiber, to form a measuring probe 20.

According to the present embodiment, the sample S as the object to be measured, that is, the wax maintained at a flow state, that is, about 40 ° C. is injected into the housing 14 through the upper opening and the lower opening. Of the object to be measured S at least around the outer circumference of the optical coupling part 12 of the optical branching device 10.
Covered in.

According to the present invention, further, as shown in FIG. 1, a light generator 30 is provided, and a signal light (light intensity P ₀ ) having a wavelength λ ₁ is incident on the first optical fiber f _1. Excuse me. In practice, a white lamp light source is used as the light generator 30,
Good results were obtained by using light close to monochromatic light having a wavelength λ ₁ of 1310 nm in a monochromator.

In the optical coupling section 12, a part or all of this signal light is transferred to the second optical fiber f ₂ depending on the optical refractive index of the substance existing around the optical coupling section 12. Then, the light is emitted from the output ports of the first and / or second optical fibers f ₁ and f ₂ with light intensities P ₁ and P ₂ , respectively.

The first and / or the second optical fiber f ₁ ,
The light emitted from the output port of f ₂ is arranged in correspondence with the output ports of the first and second optical fibers f ₁ and f ₂ , and a light receiver 31 such as a photodiode of the light quantity measuring unit 100 is provided. And 32. The signals obtained by the light receivers 31 and 32 are signal processing means,
That is, it is transmitted to the mixing ratio calculating unit 200, and the branching ratio is calculated in this mixing ratio calculating unit 200.

Now, when the amount of transmitted light is P ₁ and the amount of branched light is P ₂ , the branching ratio (R) of the optical branching device 10 is R = −10 × log (P ₁ / P ₂ ) (dB = decibel) Is defined as

As described in detail in JP-A-4-134250, there is a correlation between the amount of oil in the wax and the optical refractive index, and the branching ratio of the optical branching device 10 depends on the optical coupling part. It depends on the optical refractive index of the substance existing around 12.

Therefore, according to the present invention, regardless of the intensity of the light from the light generator 30, due to the difference in the mixing ratio of the measured object S flown to the measuring probe 20 to cover the optical coupling portion 12. In the present embodiment, the branching ratio (R) has different values due to the difference in the amount of oil component mixed in the wax.

Further, the wavelength branching characteristic of the measuring probe 20 with respect to the mixing amount of the known substance, that is, the oil content in the wax in this embodiment is input to the mixing ratio calculating unit 200. The branching ratio obtained when an unknown measured object is introduced into the optical branching device 10 is compared, and the mixing ratio of oil in the measured object is obtained.

Further, as described above with reference to FIG. 6, there is a temperature characteristic between the amount of oil in the wax and the branching ratio of the optical branching device. Therefore, when the temperature of the measured object fluctuates. Cannot accurately measure the mixing ratio.

Therefore, according to the present invention, the branching ratio is measured by the optical branching device 10 and the temperature of the object to be measured at that time is measured by the thermocouple 60. Is transmitted to the mixing ratio calculation unit 200 via.

According to the present embodiment, in the mixing ratio calculation unit 200, the mixing ratio of the oil component in the measured object obtained from the branching ratio by the optical branching device 10 is based on the temperature measurement result by the thermocouple. Then, it is corrected by comparing with the known branching ratio temperature characteristic of the optical branching device 10, and the more accurate mixing ratio of the measured object, that is, the oil amount is calculated.

FIG. 2 shows a second embodiment of the present invention.

When a conductor such as a thermocouple 60 is used to measure the temperature of the object S to be measured as in the first embodiment, it is necessary to take explosion-proof measures when it is used in a field such as oil refining. There is. Therefore, in the second embodiment, a sensor 70 is used as a temperature measuring means by enclosing an optical branching device in a known substance 50 to form a temperature measuring probe. This sensor is explosion-proof and does not require any special explosion-proof measures.

The sensor 70 receives the signal light from the light generator 71, and the light emitted from the output port is arranged in the light quantity measuring unit 102 having the same structure as the light quantity measuring unit 100 described above. The light is received by light receivers 72 and 73 such as photodiodes. The light receiver 7
The signals obtained by 2 and 73 are transmitted to the mixing ratio calculation unit 200 as a temperature measurement signal.

In this embodiment, as in the first embodiment, the branching ratio is measured by the optical branching device 10, and the temperature of the object to be measured at that time is measured by the sensor 70 as described above. .

According to the present embodiment, the mixing ratio calculation unit 200 determines the mixing ratio of oil in the object to be measured, which is obtained from the branching ratio of the optical branching device 10, based on the temperature measurement result of the sensor 70. Then, it is corrected by comparing with the known branching ratio temperature characteristic of the optical branching device 10, and the more accurate mixing ratio of the measured object, that is, the oil amount is calculated.

FIG. 3 shows a third embodiment of the present invention.

In the measuring system of the second embodiment shown in FIG. 2, a light quantity measuring unit 100 for collecting information on the mixing ratio and a light quantity measuring unit 102 for temperature measurement are provided.
I needed at least two. In the third embodiment, the light amount measuring unit 100 is also used as the light amount measuring unit 102. Therefore, in this embodiment, the light quantity measuring unit 100 is used to measure the branching ratio of the optical branching devices 10 and 70 by means such as time division or frequency division.

In FIG. 3, the light sources 71 and 30 used for the temperature measurement and the branching ratio measurement are shown as a light source changeover switch S.
A mode in which the light quantity measurement unit 100 is shared is shown by switching at W, that is, by the time division method. The method for measuring the mixing ratio of the measurement object is the same as that in the second embodiment.

According to the third embodiment, a further simplified measuring device is realized.

In each of the above embodiments, the optical branching device 10 is described as a so-called 2 × 2 optical branching device having two optical input ports and two output ports, but the present invention is not limited to this. The present invention is not limited to this, and 3 × 3 optical branching devices, 4 × 4 optical branching devices, and n × m optical branching devices can also be used effectively. Further, the optical branching device 10 can be configured by a planar waveguide instead of an optical fiber coupler.

In each of the above-mentioned examples, the explanation has been made in connection with the measurement of the mixing ratio of the oil component in the wax, but the water content in the air and the change in the alcohol content in the alcoholic brewing process are also measured in the same manner. It has been confirmed that the substance can be obtained, and the present invention can be suitably used when measuring the mixing ratio of at least one substance when a plurality of substances are mixed.

[0045]

As described above, the method and apparatus for measuring the mixing ratio of the object to be measured according to the present invention, the object to be measured is brought into contact with the optical coupling part of the optical branching device, and the branching ratio at that time is measured. By comparing this measurement result with the known branching characteristics of the optical branching device, it is configured to estimate the mixing ratio of the object to be measured, and at that time, the temperature of the object to be measured is measured, and the temperature that has been investigated in advance. Since the mixing ratio is corrected and calculated according to the characteristics, accurate measurement is possible at low cost. In particular,
Even if the temperature of the substance is unstable, the mixing ratio of at least one substance can be measured. Furthermore, the present invention maintains the function of explosion-proof,
It is possible to accurately measure the mixing ratio of at least one substance without requiring any auxiliary equipment for keeping the object to be measured at a constant temperature.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a first embodiment of an apparatus for carrying out a method for measuring a mixing ratio of an object to be measured according to the present invention.

FIG. 2 is a schematic configuration diagram of a second embodiment of an apparatus for carrying out the mixing ratio measuring method for the object to be measured according to the present invention.

FIG. 3 is a schematic configuration diagram of a third embodiment of the apparatus for carrying out the method for measuring the mixing ratio of the measured objects according to the present invention.

FIG. 4 is a schematic configuration diagram of an apparatus for implementing a conventional method for measuring a mixing ratio of an object to be measured.

FIG. 5 is a schematic configuration diagram of an apparatus for implementing a conventional method for measuring a mixing ratio of an object to be measured.

FIG. 6 is a diagram showing a temperature characteristic of a branching ratio of an optical branching device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Measuring object mixture ratio measuring device 10 Optical branching device 12 Optical coupling part 14 Housing 20 Measuring probe 30 Light generator 31, 32 Light receiving device 60, 70 Temperature measuring means 100, 102 Light intensity measuring unit 200 Mixing ratio calculating unit

Claims (2)

[Claims] 1. An object to be measured is brought into contact with an optical coupling portion of an optical branching device, a branching ratio at that time is measured, and a result of the measurement is compared with a known branching ratio characteristic of the optical branching device. In the method of measuring the mixing ratio of the measured object, the temperature of the measured object is measured, and the measured mixing ratio of the measured object is corrected by comparing with the known temperature characteristic of the optical branching device for the measured object. A method for measuring a mixing ratio of an object to be measured, which comprises obtaining a mixing ratio of the object to be measured. 2. A light-emitting device that emits light, an optical branching device including an optical waveguide having an optical coupling part, and at least the optical coupling part of the optical branching device is surrounded, and the optical coupling part is measured. A means for contacting an object, a light receiver for detecting the light branched by the optical branching device, a temperature measuring means for measuring the temperature of the object to be measured, and a signal obtained by the light receiver for processing and branching. By calculating the ratio, processing the temperature signal from the temperature measuring means to calculate the temperature, and comparing this value with the known temperature branching ratio characteristic of the optical branching device,
And a signal processing means for obtaining the mixing ratio of the measured object.