WO2018135130A1

WO2018135130A1 - Dryness measurement device and method for measuring dryness

Info

Publication number: WO2018135130A1
Application number: PCT/JP2017/042054
Authority: WO
Inventors: 泰明松儀; 康博五所尾; 志功田邉
Original assignee: アズビル株式会社
Priority date: 2017-01-23
Filing date: 2017-11-22
Publication date: 2018-07-26
Also published as: JP2018119796A

Abstract

A dryness measurement device is provided with: an inspection light emission unit 11 for emitting inspection light having a wavelength that is absorbed by a saturated liquid; a reference light emission unit 113 for emitting first and second reference lights not readily absorbed by the saturated liquid in comparison with the inspection light; an inspection tube 21 for circulating wet steam through the inside thereof, the inspection light and the first and second reference lights passing through the inspection tube 21; a light-receiving unit 12 for receiving the inspection light and the first and second reference lights passed through the inspection tube 21; an absorbance calculation unit 301 for calculating the absorbance of the wet steam with respect to the inspection light and the first and second reference lights on the basis of the inspection light and the first and second reference lights received by the light-receiving unit 12; a correction unit 302 for correcting the absorbance of the wet steam with respect to the inspection light using the absorbance of the wet steam with respect to the first and second reference lights; and a dryness specifying unit 303 for specifying the dryness of the wet steam on the basis of the corrected value of the absorbance of the wet steam with respect to the inspection light.

Description

Dryness measuring device and dryness measuring method

The present invention relates to a measurement technique, and relates to a dryness measuring apparatus and a dryness measuring method.

After the water reaches the boiling point, it becomes wet steam in which water vapor gas (gas phase portion) and water droplets (liquid phase portion) are mixed. Here, the mass ratio of the water vapor gas to the wet steam is referred to as “dryness”. Alternatively, dryness is also defined as the ratio of the difference between the specific enthalpy of wet steam and the specific enthalpy of saturated liquid to the specific enthalpy of latent heat.

For example, if water vapor gas and water droplets are present in half, the dryness is 0.5. Moreover, when there is no water droplet and only water vapor gas is present, the dryness is 1.0. From the viewpoints of effectively utilizing the sensible heat and latent heat possessed by wet steam in heat exchangers, etc., and preventing corrosion of turbine blades in steam turbines, the wet steam dryness is controlled. It is desired to be in a state close to 1.0. Therefore, various methods for measuring the dryness have been proposed.

For example, Patent Document 1 uses a saturated steam table based on the wet steam flow rate and pressure before and after the pressure control valve, using the fact that there is no change in the total enthalpy before and after the pressure control valve provided in the pipe. A technique for calculating dryness by obtaining saturated water enthalpy and saturated steam enthalpy is disclosed. However, since the technique disclosed in Patent Document 1 needs to change the wet vapor of the measurement object from the two-phase state to the gas phase state and further stabilize the measurement object in the gas phase state, measurement of dryness There is a problem that it takes time. On the other hand, Patent Document 2 discloses a technique for optically measuring the dryness. Patent Document 3 discloses a technique for measuring dryness using two lights having different wavelengths.

JP-A-8-312908 Japanese Unexamined Patent Publication No. 2016-57203 Japanese Unexamined Patent Publication No. 2016-85059

Further improvement of the conventional dryness measuring device is desired. Accordingly, an object of the present invention is to provide a dryness measuring apparatus and a dryness measuring method capable of accurately measuring the dryness.

According to the aspect of the present invention, the inspection light emitting unit that emits inspection light having at least a wavelength that is absorbed by the saturated liquid, and the first and second reference lights that are less likely to be absorbed by the saturated liquid than the inspection light are emitted. A reference light emitting unit, an inspection tube for flowing wet steam therein, an inspection tube through which the inspection light and the first and second reference light pass, an inspection light that has passed through the inside of the inspection tube, and the first and second Based on the light receiving unit that receives the reference light, the inspection light received by the light receiving unit, and the first and second reference light, the absorbance of the wet steam by each of the inspection light and the first and second reference light is calculated. Based on a correction value for correcting the absorbance of the wet steam by the first and second reference lights, and a correction value for the absorbance of the wet steam by the test light. A dryness specifying section for specifying the dryness of the Measuring device is provided.

In the dryness measuring apparatus, the inspection tube may include a window through which the inspection light and the first and second reference lights pass.

In the dryness measuring apparatus, the correction value of the absorbance of the wet steam by the inspection light is determined so that the inspection light and the second reference light have a wavelength difference between the first reference light and the second reference light from the absorbance of the wet steam by the inspection light. A value obtained by multiplying the first coefficient which is the ratio of the wavelength difference of the reference light by the absorbance of the wet steam by the first reference light, and a second coefficient corresponding to a value obtained by subtracting the first coefficient from 1 It may correspond to a value obtained by subtracting the value obtained by multiplying the absorbance of the wet steam by the reference light of 2. Here, the equivalent includes the same thing. The calculation order is not limited.

A data storage device in which the dryness measuring device stores a first coefficient that is a ratio of a wavelength difference between the inspection light and the second reference light to a wavelength difference between the first reference light and the second reference light. Furthermore, you may provide.

The dryness measuring apparatus may further include a data storage device that stores a second coefficient corresponding to a value obtained by subtracting the first coefficient from 1.

In the dryness measuring apparatus, the correction value of the absorbance of the wet steam by the inspection light includes saturated water flowing through the inside of the inspection tube by the first reference light and the second reference light from the absorbance of the wet steam by the inspection light. The first coefficient, which is the ratio of the difference in absorbance of the gas that does not contain saturated water flowing through the inside of the test tube due to the test light and the second reference light, to the difference in absorbance of the gas that is not present, is the wet steam by the first reference light. Even if it corresponds to a value obtained by subtracting the value obtained by multiplying the absorbance by the second coefficient corresponding to the value obtained by subtracting the first coefficient from 1 and the value obtained by multiplying the absorbance of the wet vapor by the second reference light. Good. Here, the equivalent includes the same thing. The calculation order is not limited.

The dryness measuring device described above is configured so that the inside of the inspection tube by the inspection light and the second reference light with respect to the difference in absorbance of the gas not containing saturated water flowing through the inside of the inspection tube by the first reference light and the second reference light You may further provide the data storage device which preserve | saves the 1st coefficient which is a ratio of the difference of the light absorbency of the gas which does not contain the flowing saturated water.

Further, according to the aspect of the present invention, the inspection light having at least a wavelength that is absorbed by the saturated liquid is emitted to the wet steam, and the first and second reference lights that are less likely to be absorbed by the saturated liquid than the inspection light. , The inspection light passing through the wet steam, receiving the first and second reference lights, the received inspection light, the inspection light based on the first and second reference lights, Calculating the absorbance of the wet steam by each of the first and second reference lights, correcting the absorbance of the wet steam by the test light with the absorbance of the wet steam by the first and second reference lights, A method of measuring dryness is provided, including identifying the dryness of the wet steam based on a correction value of the absorbance of the wet steam by light.

In the dryness measurement method described above, wet steam may flow inside the inspection tube, and the inspection tube may include a window through which the inspection light and the first and second reference lights pass.

In the dryness measurement method, the correction value of the absorbance of the wet vapor by the inspection light is determined so that the inspection light and the first reference light with respect to the wavelength difference between the first reference light and the second reference light are determined from the absorbance of the wet vapor by the inspection light. A value obtained by multiplying the first coefficient which is the ratio of the wavelength difference of the two reference lights by the absorbance of the wet steam by the first reference light, and a second coefficient corresponding to a value obtained by subtracting the first coefficient from 1 It may correspond to a value obtained by subtracting the value obtained by multiplying the absorbance of the wet steam by the second reference light. Here, the equivalent includes the same thing. The calculation order is not limited.

In the dryness measurement method described above, the correction value of the wet steam absorbance due to the inspection light is the saturated water flowing in the test tube due to the first reference light and the second reference light based on the wet steam absorbance due to the inspection light. The first coefficient which is the ratio of the difference in absorbance of the gas not containing saturated water flowing through the inside of the test tube by the test light and the second reference light to the difference in absorbance of the gas not containing the wet steam by the first reference light Corresponding to the value obtained by subtracting the value obtained by multiplying the absorbance of the second reference light by the second coefficient corresponding to the value obtained by subtracting the first coefficient from 1 and the value obtained by multiplying the absorbance of the wet vapor by the second reference light. Also good. Here, the equivalent includes the same thing. The calculation order is not limited.

According to the present invention, it is possible to provide a dryness measuring device and a dryness measuring method capable of accurately measuring the dryness.

It is a schematic diagram of the dryness measuring apparatus which concerns on 1st Embodiment. It is a graph which shows the state change of the water in the standard atmospheric pressure which concerns on 1st Embodiment. It is a graph which shows the absorption spectrum of the saturated vapor | steam and saturated liquid which concern on 1st Embodiment. It is a graph which shows the absorption spectrum of the saturated vapor | steam and saturated liquid which concern on 1st Embodiment, and the relationship of a dryness. It is a graph which shows the absorption spectrum of the saturated vapor | steam and saturated liquid which concern on 1st Embodiment, and the relationship of a dryness. It is a typical graph which shows the relationship between the wavelength of light at the time of flowing wet steam through the test | inspection tube which concerns on 1st Embodiment, and a light absorbency. It is a typical graph which shows the relationship between the wavelength of light and the light absorbency at the time of flowing the gas which does not contain saturated water to the test tube which concerns on 2nd Embodiment. It is a graph which shows the relationship between the temperature of the test tube which concerns on Example 1, and received light intensity. It is a graph which shows the relationship between the temperature of the test tube which concerns on Example 2, and the measured dryness. It is a schematic diagram of the dryness measuring apparatus which concerns on other embodiment.

Embodiments of the present invention will be described below. In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals. However, the drawings are schematic. Therefore, specific dimensions and the like should be determined in light of the following description. Moreover, it is a matter of course that portions having different dimensional relationships and ratios are included between the drawings.

(First embodiment)
As shown in FIG. 1, the dryness measuring apparatus according to the first embodiment absorbs the inspection light emitting unit 11 that emits inspection light having at least a wavelength absorbed by the saturated liquid, and the saturated liquid as compared with the inspection light. A reference light emitting unit 113 that emits first and second reference light that is difficult to be generated, and a test tube 21 that allows wet steam to flow therein, and a test tube 21 through which the test light and the first and second reference light pass. And a light receiving unit 12 that receives the inspection light passing through the inside of the inspection tube 21 and the first and second reference lights.

The dryness measuring device further calculates the absorbance of the wet vapor by each of the inspection light and the first and second reference lights based on the inspection light and the first and second reference lights received by the light receiving unit 12. Based on the absorbance calculation unit 301, the correction unit 302 that corrects the absorbance of the wet vapor by the first and second reference lights with the absorbance of the wet vapor by the inspection light, and the correction value of the absorbance of the wet vapor by the inspection light A dryness specifying unit 303 for specifying the dryness of the steam. The absorbance calculation unit 301, the correction unit 302, and the dryness specification unit 303 are included in, for example, a central processing unit (CPU) 300.

The test tube 21 can pass wet steam in which saturated steam and saturated liquid are combined. As shown in FIG. 2, under standard atmospheric pressure, water reaches a boiling point (100 ° C.), and then water as droplets and steam are mixed to form wet steam in a coexisting state. When the pressure is constant, since the latent heat of wet steam changes due to heating and cooling, the saturation temperature is constant. Here, as given by the following equation (1), the mass ratio of saturated steam to the total amount of wet steam is referred to as “dryness”.
Therefore, the dryness of the saturated steam is 1, and the dryness of the saturated liquid is 0.
z = m _vapor / (m _vapor + m _water ) (1)
z represents the degree of dryness, m _vapor represents the mass of saturated vapor, and m _water represents the mass of saturated liquid.

Here, the mass of the saturated vapor is proportional to the absorbance of the saturated vapor. Further, the mass of the saturated liquid is proportional to the absorbance of the saturated liquid. Therefore, the following equation (2) is derived from the above equation (1).
z = m _vapor / (m _vapor + m _water )
= a _vapor / (a _vapor + k × a _water ) (2)
a _vapor represents the absorbance of the saturated vapor, a _water represents the absorbance of the saturated liquid, and k represents the molar extinction coefficient ratio given by the following equation (3).
k = e _vapor / e _water (3)
e _vapor represents the extinction coefficient of saturated vapor, and e _water represents the extinction coefficient of saturated liquid.

The absorbance As of the wet steam is given by the sum of the absorbance of the saturated steam and the absorbance of the saturated liquid, as given by the following equation (4).
As = a _vapor + a _water (4)
Further, the absorbance of the wet vapor is given by the logarithm of the ratio of the light intensity of the light after passing through the wet steam to the light intensity of the light before passing through the wet steam as given by the following equation (5). .
As = -ln (I _steam1 / I _steam0 ) (5)
I _steam0 represents the light intensity of light before the wet steam is transmitted or when there is no wet steam, and I _steam1 represents the light intensity of the light after transmitted through the wet steam.

As shown in FIG. 3, the absorption spectra of the saturated vapor and the saturated liquid are different. When the dryness changes, the absorption spectrum of the saturated liquid changes. For example, as the dryness changes from 0 to 1, the content of the saturated liquid in the wet steam decreases, so the absorbance As of the wet steam at the peak wavelength of the absorption spectrum of the saturated liquid also decreases as shown in FIG. To do. The wavelength at the peak of the absorption spectrum of the saturated liquid is around 1880 nm. In wet steam, since the volume of saturated steam is much larger than the volume of saturated liquid, the absorbance of saturated steam can be regarded as constant if the pressure is constant.

The dryness of the wet steam is also given by the following equation (6) derived from the above equations (2), (4), and (5).
z = 1 / (1-k + (k / a _vapor ) × A _S ) (6)
The molar extinction coefficient ratio k is a constant. As described above, the absorbance a _Vapor saturated steam can be considered a constant under constant pressure, the absorbance a _Vapor saturated steam can be derived from the pressure of the wet steam. Therefore, by measuring the absorbance A _S of wet steam, it is possible to calculate the dryness fraction z of wet steam from (6).

The inspection light emitting unit 11 shown in FIG. 1 emits inspection light including a wavelength band that is absorbed by the saturated liquid. The inspection light is, for example, near infrared light having a wavelength region of 800 nm to 2500 nm. The wavelength band of the inspection light and the wavelength bands of the first and second reference lights may partially overlap. As shown in FIG. 5, the inspection light may have the peak wavelength of the absorption spectrum of the saturated liquid as the center wavelength. In the wavelength region, the absorption spectra of the saturated vapor and the saturated liquid overlap. A light emitting diode or the like can be used for the inspection light emitting unit 11 shown in FIG.

The first and second reference lights emitted from the reference light emitting unit 113 have different wavelengths. The wavelength of the second reference light is longer than the wavelength of the first reference light. For example, the wavelength of the inspection light may be between the first and second reference lights. Alternatively, the wavelengths of the first and second reference lights may be longer than the wavelength of the inspection light. Alternatively, the wavelengths of the first and second reference lights may be shorter than the wavelength of the inspection light. As shown in FIG. 5, each of the first and second reference lights has a wavelength that is difficult to be absorbed by wet steam in the entire range of dryness. The wavelength band that is difficult to be absorbed by the wet steam is, for example, less than 1300 nm and near 1600 nm to 1800 nm.

The reference light emitting unit 113 illustrated in FIG. 1 may include a first reference light emitting unit 111 that emits first reference light and a second reference light emitting unit 112 that emits second reference light. Good. For the first reference light emitting unit 111 and the second reference light emitting unit 112, a light emitting diode or the like can be used.

The inspection optical waveguide 30 for propagating the inspection light is arranged facing the inspection light emitting unit 11. A first reference optical waveguide 130 that propagates the first reference light is disposed facing the first reference light emitting unit 111. In addition, a second reference optical waveguide 230 that propagates the second reference light is disposed facing the second reference light emitting unit 112. The multiplexer 14 is connected to the inspection optical waveguide 30, the first reference optical waveguide 130, and the second reference optical waveguide 230. A multiplexer optical waveguide 31 for propagating the inspection light combined with the multiplexer 14 and the first and second reference lights into the inspection tube 21 is connected to the multiplexer 14.

For example, light-transmitting

windows

121A and 121B are provided on the side wall of the test tube 21. The window 121A provided in the inspection tube 21 and the window 121B are opposed to each other. The

windows

121A and 121B are made of heat resistant glass such as quartz glass or sapphire glass. The heat resistant test tube 21 provided with the

windows

121A and 121B is, for example, a sight glass. The multiplexed optical waveguide 31 is connected to the outer surface of a window 121A provided in the test tube 21, for example. A collimator lens may be disposed between the end of the multiplexed optical waveguide 31 and the outer surface of the window 121A.

The inspection light emitted from the end of the combined optical waveguide 31 is absorbed by the saturated liquid contained in the wet steam inside the inspection tube 21. As described above, the saturated liquid contained in the wet steam decreases as the dryness approaches from 0 to 1. Therefore, as the dryness of the wet steam in the test tube 21 approaches 0 to 1, the absorbance of the wet steam with respect to the test light tends to decrease.

The inspection light emitted from the end portion of the combined optical waveguide 31 and a part of the first and second reference lights are reflected, scattered, and refracted by the laminar flow or wave flow of the saturated liquid inside the inspection tube 21. Can be equal. Therefore, the inspection light and the first and second reference lights can be attenuated by reflection, scattering, refraction, and the like.

In addition, the

windows

121A and 121B may be deteriorated or dirty. Examples of deterioration of the

windows

121A and 121B include white discoloration, blue discoloration, and latent scratches. As an example of the stain | pollution | contamination adhering to

window

121A, 121B, the rust which scattered inside the test tube 21 is mentioned. Deterioration and contamination of the

windows

121A and 121B may worsen over time. The inspection light emitted from the end portion of the multiplexed optical waveguide 31 and the first and second reference lights can be attenuated due to deterioration or contamination of the

windows

121A and 121B.

According to the knowledge found by the present inventors, the light attenuation due to deterioration and dirt of the

windows

121A and 121B depends on the wavelength of light, and the light attenuation due to deterioration and dirt of the

windows

121A and 121B and the light. The wavelength of is generally in a linear relationship. When the wavelength of the second reference light is longer than the wavelength of the first reference light, for example, the attenuation of the first reference light due to deterioration or contamination of the

windows

121A and 121B is the first attenuation due to deterioration or contamination of the windows 121A and 121B. 2 is greater than the attenuation of the reference light.

The light receiving waveguide 51 into which the inspection light passing through the inside of the inspection tube 21 and the first and second reference lights enter is connected to the outer surface of the window 121B of the inspection tube 21. The end of the light receiving waveguide 51 is opposed to the end of the combined optical waveguide 31. Between the outer surface of the window 121B and the end of the light receiving waveguide 51, a lens that allows the inspection light and the first and second reference lights to enter the light receiving waveguide 51 may be disposed. The light receiving waveguide 51 guides the inspection light transmitted through the inside of the inspection tube 21 and the first and second reference lights to the light receiving unit 12. A light intensity detection element such as a photodiode can be used for the light receiving unit 12.

The inspection optical waveguide 30, the first reference optical waveguide 130, the second reference optical waveguide 230, the combined optical waveguide 31, and the light receiving waveguide 51 include polymethyl methacrylate resin (PMMA: Poly (methymethacrylate)). A single core optical fiber made of plastic such as glass and a single core optical fiber made of glass such as quartz glass can be used. However, if the inspection light and the first and second reference lights can be propagated, these can be used. It is not limited to.

The dryness measuring apparatus according to the first embodiment may further include a pressure sensor 16 that measures the pressure of the wet steam in the test tube 21. However, the pressure information may be obtained from upstream or downstream of the inspection tube 21.

The light receiving unit 12 and the pressure sensor 16 are connected to the CPU 300. A data storage device 400 is connected to the CPU 300. For example, the data storage device 400 stores a relational expression between the absorbance of the wet steam and the dryness of the wet steam as in the above formula (6).

The absorbance calculation unit 301 included in the CPU 300 receives from the light receiving unit 12 the measurement values of the inspection light transmitted through the wet steam inside the inspection tube 21 and the light intensity of the first and second reference lights. The absorbance calculation unit 301 specifies the absorbance A _Lx of the wet vapor in the test tube 21 by the test light based on the light intensity of the test light received by the light receiving unit 12. The light intensity of the inspection light before passing through the wet steam or when there is no wet steam in the inspection tube 21 may be a value measured in advance as a constant.

In addition, the absorbance calculation unit 301 specifies the absorbance A _L1 of the wet steam in the test tube 21 by the first reference light based on the light intensity of the first reference light received by the light receiving unit 12. Further, the absorbance calculation unit 301 specifies the absorbance A _L2 of the wet steam in the test tube 21 by the second reference light based on the light intensity of the second reference light received by the light receiving unit 12.

As shown in FIG. 6, the measurement value of the wet steam absorbance A _Lx by the inspection light is affected by the deterioration At _tx of the inspection light due to the deterioration of the

windows

121A and 121B and dirt. Therefore, the corrected absorbance _AbLx of the wet vapor due to the inspection light, excluding the influence of the attenuation degree _AtLx of the inspection light due to the deterioration or dirt of the

windows

121A and 121B, is given by the following equation (7).
A _bLx = A _Lx -A _tLx (7)

As described above, the first reference light has a wavelength that is difficult to be absorbed by water. Therefore, the measured value of the wet steam absorbance A _L1 by the first reference light is substantially the attenuation of the first reference light due to deterioration or contamination of the

windows

121A and 121B, as shown in the following equation (8). It can be regarded as the degree A _tL1 .
A _L1 = A _tL1 (8)

The second reference light also has a wavelength that is difficult to be absorbed by water. Therefore, the measured value of the wet steam absorbance A _L2 by the second reference light is substantially the attenuation of the second reference light due to deterioration or contamination of the

windows

121A and 121B, as shown in the following equation (9). It can be regarded as the degree _AtL2 .
A _L2 = A _tL2 (9)

As described above, since the light wavelength and the light attenuation due to the deterioration and dirt of the

windows

121A and 121B are in a linear relationship, the inspection light attenuation At _Lx due to the deterioration and dirt of the

windows

121A and 121B. Is expressed using a predetermined coefficient m _k and the first and second reference light attenuations A _tL1 and A _tL2 due to deterioration and contamination of the

windows

121A and 121B, as shown in the following equation (10). be able to.
A _tLx = m _k A _tL1 + (1-m _k ) A _tL2 (10)
From the above equations (7) to (10), the corrected absorbance _AbLx of the wet steam by the inspection light is given by the following equation (11).
_{_{A bLx = A Lx - [m}} k A L1 + (1-m k) A L2] (11)

When the wavelength of the inspection light is Lx, the wavelength of the first reference light is L1, and the wavelength of the second reference light is L2, the coefficient m _k is given by the following equation (12).
m _k = (Lx-L2) / (L1-L2) (12)

The correction unit 302 illustrated in FIG. 1 calculates the corrected absorbance _AbLx of the wet steam by the inspection light using, for example, the above equation (11). The corrected absorbance A _bLx of the wet vapor by the inspection light is an inspection with respect to the wavelength difference (L1−L2) between the first reference light and the second reference light from the measured value A _Lx of the wet vapor absorbance by the inspection light. A value m _k A _L1 _obtained by multiplying the measurement value A _L1 of the absorbance of the wet vapor by the first reference light by the first coefficient m _k which is the ratio of the wavelength difference (Lx−L2) between the light and the second reference light. A value obtained by multiplying the measured value A _L2 of the wet steam absorbance by the second reference light by a second coefficient (1-m _k ) corresponding to a value _obtained by subtracting the first coefficient m _k from 1 (1-m _k ) corresponds to a value obtained by subtracting A _L2 . Note that the coefficient m _k may be a constant calculated in advance. At least one of the first coefficient m _k and the second coefficient (1−m _k ) may be stored in the data storage device 400.

The dryness specifying unit 303 receives the corrected absorbance _AbLx of wet steam from the correcting unit 302. Further, the dryness specifying unit 303 receives the measured value of the pressure of the wet steam in the test tube 21 from the pressure sensor 16.

Based on the measured value of the pressure of the wet steam in the test tube 21 received from the pressure sensor 16, the dryness specifying unit 303 calculates the absorbance a _vapor of saturated vapor depending on the pressure. Furthermore, the dryness of the identifying unit 303, for example, the (6) assigns the value of absorbance A _BLX of the corrected wet steam in the expression of the variable A _s, the value of absorbance a _Vapor saturated steam calculated in the variable a _Vapor By substituting, the dryness z of the wet steam in the inspection tube 21 is calculated. However, if the pressure is constant, the absorbance a _vapor of the saturated vapor can be regarded as constant. Therefore, if the pressure in the test tube 21 is constant, a constant may be used for the absorbance a _vapor of the saturated vapor. In this case, the dryness measuring apparatus according to the first embodiment may not include the pressure sensor 16.

Further, an input device 321, an output device 322, a program storage device 323, and a temporary storage device 324 are connected to the CPU 300. As the input device 321, a switch, a keyboard, and the like can be used. The relational expression stored in the data storage device 400 is input using the input device 321, for example. As the output device 322, an optical indicator, a digital indicator, a liquid crystal display device, or the like can be used.

The output device 322 outputs, for example, the dryness value of the wet steam inside the test tube 21 specified by the dryness specifying unit 303. The program storage device 323 stores a program for causing the CPU 300 to execute data transmission / reception between devices connected to the CPU 300. The temporary storage device 324 temporarily stores data in the calculation process of the CPU 300.

According to the dryness measuring apparatus according to the first embodiment described above, it is possible to accurately measure the dryness of the wet steam even if the light is attenuated by factors other than the light absorption by the wet steam. In addition, according to the dryness measuring apparatus according to the first embodiment, it is possible to accurately measure the dryness of the wet steam even if the light attenuation due to factors other than the light absorption by the wet steam changes with time. .

(Second Embodiment)
When a gas that does not contain saturated water flows in the inspection tube 21 shown in FIG. 1, the measured value of the gas absorbance A _Lx-0 by the inspection light is substantially as shown in the following equation (13). It can be regarded as the attenuation degree _AtLx of the inspection light due to deterioration or dirt of the

windows

121A and 121B. In addition, the gas which does not contain saturated water is air | atmosphere, for example.
A _Lx-0 = A _tLx (13)

In addition, when a gas not containing saturated water is caused to flow through the test tube 21, the measured value of the gas absorbance A _L1-0 by the first reference light is substantially the deterioration or dirt of the

windows

121A and 121B. _Can be regarded as the attenuation degree A _tL1 of the first reference light. Similarly, the measured value of the gas absorbance A _L2-0 by the second reference light can be _{substantially} regarded as the second reference light attenuation At _L2 due to deterioration or contamination of the

windows

121A and 121B. It is.

In this case, the relationship between the measured values A _Lx-0 , A _L1-0 , A _L2-0 of the _absorbance and the wavelengths Lx, L1, L2 is as shown in FIG. The coefficient m _k given by is also given by the following equation (14).
m _k = (A _LX-0 -A _L2-0 ) / (A _L1-0 -A _L2-0 ) (14)
Therefore, the correction unit 302 shown in FIG. 1 uses measured values A _Lx-0 , A _L1-0 , A _L2-0 obtained in advance by flowing a gas not containing saturated water into the test tube 21. The corrected absorbance _AbLx of the wet steam by the inspection light may be calculated by the above equation (11) using the coefficient m _k calculated in the above. At least one of the first coefficient m _k and the second coefficient (1−m _k ) may be stored in the data storage device 400.

In the second embodiment, the corrected absorbance _AbLx of the wet steam by the inspection light is obtained by _{calculating the} saturated water by the first reference light and the second reference light from the measured value A _Lx of the wet steam absorbance by the inspection light. Difference in absorbance (A _Lx-0 -A _L2-0 ) of the gas not containing saturated water due to the inspection light and the second reference light to the difference in absorbance (A _L1-0 -A _L2-0 ) of the gas not containing A value m _k A _L1 _obtained by multiplying the measured value A _L1 of the wet steam absorbance by the first reference light by the first coefficient m _k , which is the ratio of 1, and a value _obtained by subtracting the first coefficient m _k from 1 This value is equivalent to a value obtained by subtracting (1−m _k ) A _L2 _obtained by multiplying the second coefficient (1−m _k ) by the measured value A _L2 of the wet steam absorbance by the second reference light.

The wavelengths of the inspection light and the first and second reference lights are not single and may have a predetermined bandwidth. In this case, as shown in the above equation (12), rather than using the coefficient m _k calculated based on the wavelength, as shown in the above equation (14), it is based on the absorbance of the gas not containing saturated water. By using the coefficient m _k calculated in this way, it is possible to accurately correct the absorbance of the wet vapor due to the inspection light.

Example 1
In the case where there are no white burns in the

windows

121A and 121B of the inspection tube 21 shown in FIG. 1, the air was passed through the inspection tube 21, and the received light intensity of the inspection light and the first and second reference light was measured. Next, in each of a state in which wet steam is passed through the inspection tube 21 to strongly cool the inspection tube 21, a state in which the inspection tube 21 is lightly cooled, a state in which the inspection tube 21 is at room temperature, and a state in which the inspection tube 21 is heated. The received light intensity of the inspection light and the first and second reference lights was measured.

In addition, when there were white discoloration in the

windows

121A and 121B of the inspection tube 21, the atmosphere was passed through the inspection tube 21, and the received light intensity of the inspection light and the first and second reference light was measured. Next, in each of a state in which wet steam is passed through the inspection tube 21 to strongly cool the inspection tube 21, a state in which the inspection tube 21 is lightly cooled, a state in which the inspection tube 21 is at room temperature, and a state in which the inspection tube 21 is heated. The received light intensity of the inspection light and the first and second reference lights was measured.

The lower the temperature of the test tube 21, the lower the dryness, and the higher the temperature of the test tube 21, the higher the dryness. When the inspection light and the first and second reference light received intensities are normalized to 100% when the atmosphere flows through the inspection tube 21 when the

windows

121A and 121B of the inspection tube 21 do not have white discoloration. FIG. 8 is a graph plotting the received light intensity of the inspection light and the first and second reference lights.

If there are white discoloration in the

windows

121A and 121B of the test tube 21 shown in FIG. 1, particularly when the atmosphere or wet steam having a high dryness flows through the test tube 21, the test light and the first and second reference lights. It was confirmed that the received light intensity decreased.

(Example 2)
Using the dryness measuring apparatus including the correction unit described in the second embodiment, the dryness is measured when there are no white burns and when there are white burns in the

windows

121A and 121B of the test tube 21 shown in FIG. did. As a result, as shown in FIG. 9, even when the

windows

121A and 121B had white discoloration, the dryness was almost the same as when there was no white discoloration.

Next, without using the second reference light, a value obtained by subtracting the absorbance of the wet vapor due to the first reference light from the absorbance of the wet vapor due to the inspection light is used as a correction value for the absorbance of the wet vapor due to the inspection light. The dryness which concerns on a comparative example was measured. As a result, as shown in FIG. 9, it was confirmed that when the window 121 </ b> A, 121 </ b> B has white discoloration, an error occurs when the dryness increases.

(Other embodiments)
Although the present invention has been described by the embodiments as described above, it should not be understood that the description and drawings constituting a part of this disclosure limit the present invention. From this disclosure, various alternative embodiments, examples and operational techniques should be apparent to those skilled in the art.

For example, as shown in FIG. 10, in the dryness measuring apparatus, a window 121 in which both the end of the combined optical waveguide 31 and the end of the light receiving waveguide 51 are provided on one side wall of the test tube 21. May be arranged in parallel. In this case, the reflecting plate 131 is disposed on the side wall inside the test tube 21 facing the end of the combined optical waveguide 31 and the end of the light receiving waveguide 51. The inspection light and the first and second reference light emitted from the end of the combined optical waveguide 31 travel through the inspection tube 21, are reflected by the reflection plate 131, and enter the light receiving waveguide 51. Here, the angles of the inspection light and the first and second reference light emitted from the end portion of the combined optical waveguide 31 are determined by the light transmitting window 121 provided in the inspection tube 21 and the first and first light beams. 2 below the critical angle at which the reference light is totally reflected, and below the critical angle at which the inspection light and the first and second reference light are totally reflected at the surface of the laminar flow or the wavy flow of the saturated liquid inside the inspection tube 21 There is no particular limitation.

Thus, it should be understood that the present invention includes various embodiments and the like.

The dryness measuring device according to the embodiment of the present invention is a visualization of the latent heat increase effect by the pressure reducing valve, dryness measurement to obtain the optimum boiler efficiency, wet loss measurement of the steam turbine, optimal dryness control of the heat exchanger, It can be used for the control of food production processes such as a noodle-making process and the control of chemical processes.

DESCRIPTION OF SYMBOLS 11 ... Inspection light emission part, 12 ... Light-receiving part, 14 ... Multiplexer, 16 ... Pressure sensor, 21 ... Inspection tube, 30 ... Inspection optical waveguide, 31 ... Combined optical waveguide, 51... Light receiving waveguide, 111... First reference light emitting unit, 112... Second reference light emitting unit, 113. , 121B ... window, 130 ... first reference optical waveguide, 131 ... reflector, 230 ... second reference optical waveguide, 300 ... central processing unit, 301 ... absorbance Calculation unit 302... Correction unit 303. Dryness specifying unit 321... Input device 322... Output device 323... Program storage device 324. ... Data storage devices

Claims

An inspection light emitter that emits inspection light having at least a wavelength absorbed by the saturated liquid;
A reference light emitter that emits first and second reference light that is less likely to be absorbed by the saturated liquid as compared to the inspection light;
An inspection tube for flowing wet steam therein, through which the inspection light and the first and second reference light pass;
A light receiving unit that receives the inspection light that has passed through the inspection tube, the first and second reference lights, and
Based on the inspection light and the first and second reference lights received by the light receiving unit, an absorbance calculation unit that calculates the absorbance of the wet steam by each of the inspection light and the first and second reference lights. When,
A correction unit that corrects the absorbance of the wet steam by the inspection light with the absorbance of the wet steam by the first and second reference lights;
Based on the correction value of the absorbance of the wet steam by the inspection light, a dryness specifying unit for specifying the dryness of the wet steam,
A dryness measuring device.
The dryness measuring apparatus according to claim 1, wherein the inspection tube includes a window through which the inspection light and the first and second reference lights pass.
The correction value of the absorbance of the wet steam by the inspection light is
From the absorbance of the wet vapor by the inspection light,
A first coefficient that is a ratio of a wavelength difference between the inspection light and the second reference light with respect to a wavelength difference between the first reference light and the second reference light is the wet steam by the first reference light. The value multiplied by the absorbance of
A value obtained by multiplying the absorbance of the wet steam by the second reference light by a second coefficient corresponding to a value obtained by subtracting the first coefficient from 1;
Equivalent to the value minus
The dryness measuring apparatus according to claim 1 or 2.
The dryness measuring apparatus according to claim 3, further comprising a data storage device for storing the first coefficient.
The dryness measuring apparatus according to claim 3 or 4, further comprising a data storage device for storing the second coefficient.
The correction value of the absorbance of the wet steam by the inspection light is
From the absorbance of the wet vapor by the inspection light,
Saturation flowing through the inspection tube by the inspection light and the second reference light with respect to a difference in absorbance of a gas not containing saturated water flowing through the inspection tube by the first reference light and the second reference light. A value obtained by multiplying the absorbance of the wet vapor by the first reference light by a first coefficient which is a ratio of the difference in absorbance of a gas not containing water;
A value obtained by multiplying the absorbance of the wet steam by the second reference light by a second coefficient corresponding to a value obtained by subtracting the first coefficient from 1;
Equivalent to the value minus
The dryness measuring apparatus according to claim 1 or 2.
The dryness measuring apparatus according to claim 6, further comprising a data storage device for storing the first coefficient.
The dryness measuring apparatus according to claim 6 or 7, further comprising a data storage device for storing the second coefficient.
Emitting test light having at least a wavelength absorbed by the saturated liquid to wet steam;
Emitting first and second reference light to the wet steam that is less likely to be absorbed by the saturated liquid compared to the inspection light;
Receiving the inspection light that has passed through the wet steam, the first and second reference lights;
Calculating the absorbance of the wet steam by each of the inspection light and the first and second reference lights based on the received inspection light and the first and second reference lights;
Correcting the absorbance of the wet vapor by the inspection light with the absorbance of the wet vapor by the first and second reference lights;
Identifying the wet steam dryness based on the correction value of the absorbance of the wet steam by the inspection light; and
Method for measuring dryness, including
The wet steam flows inside the test tube,
The inspection tube includes a window through which the inspection light and the first and second reference lights pass.
The dryness measuring method according to claim 9.