WO2014188891A1 - Dryness measurement device and piping for wet steam - Google Patents

Abstract

The present invention addresses the problem of suppressing the heat loss that occurs when the dryness of wet steam is measured using light and measuring dryness with high accuracy. The present invention is provided with a light introduction unit (11) for causing light to pass through a light entry opening (A1) provided in piping (30) through which wet steam (SA) under measurement flows; a light reception unit (12) for receiving, from a light exit opening (A2) provided in the piping (30), light that has passed through or been reflected by the wet steam (SA) and outputting a detection signal (Sd); a dryness determining unit (13) for referring to the detection signal (Sd) and determining the dryness of the wet steam (SA); and heat loss compensation devices (20, 21, 22) for compensating for the heat loss of the light entry opening (A1), the light exit opening (A2), or both.

Description

Dryness measuring device and piping for wet steam

The present invention relates to a wet steam measuring device and a wet steam pipe.

After water reaches the boiling point, it becomes wet steam in which water vapor gas (gas phase part: saturated steam) and water droplets (liquid phase part: saturated water) are mixed. Here, the weight ratio of the water vapor gas to the wet steam is referred to as “dryness”. 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, the invention described in Patent Document 1 utilizes the fact that there is no change in the total enthalpy before and after the pressure control valve provided in the pipe, and based on the wet steam flow and pressure before and after the pressure control valve, the saturated steam table It is related with the technique which calculates | requires saturated water enthalpy and saturated vapor | steam enthalpy using, and calculates dryness.

The invention described in Patent Document 2 allows light of a plurality of wavelengths to pass through wet steam from a broadband light source, detects light of a plurality of wavelengths that has passed through the wet steam with an optical detector, and provides dry steam for each wavelength of light. Determining the intensity ratio of the intensity of the detected light to the intensity of the light as it passes through, calculating a scaled intensity ratio by successively applying a scaling factor to the intensity ratio, and for each of the scaling factors, Calculate the residual, determine the minimum residual of the multiple residuals, determine the droplet size distribution by calculating the number density of droplets corresponding to the minimum residual, and based on the droplet size distribution The present invention relates to a technique for determining the steam weight ratio.

JP-A-8-312908 JP 2012-103254 A

Here, the technique disclosed in Patent Document 1 has a long time constant of a sensor that detects the flow rate and pressure of wet steam, and changes the state of the wet steam to be measured from a two-phase state to a gas phase state. Since it is necessary to stabilize the measurement object in the gas phase, there is a problem that it takes time to measure the dryness, and it is not suitable for measuring the dryness in a transient state until the wet steam is stabilized. For this reason, the inventor of the present application has studied the improvement of the technique for measuring the dryness of the wet steam by passing light through the wet steam as described in Patent Document 2.

However, in the technology that measures the dryness of the wet steam by light, heat loss occurs in the light incident part and emission part to the pipe through which the wet steam circulates, resulting in condensation of the wet steam and stagnation of the liquid phase, There was a problem that the dryness of wet steam could not be measured accurately.

Therefore, an object of the present invention is to measure the dryness with high accuracy by suppressing heat loss that occurs when measuring the dryness of wet steam by light.

The inventor of the present application diligently studied a technique for measuring the dryness of wet steam using light. Specifically, the present invention provides the following means to overcome the above problems and solve the above problems. I came up with it.

(1) The dryness measuring apparatus according to the present invention transmits a light incident portion through which light enters from an incident opening provided in a pipe through which wet steam to be measured flows, and transmits the wet steam from an injection opening provided in the pipe. Alternatively, the light receiving unit that receives the reflected light and outputs a detection signal, the dryness specifying unit that specifies the dryness of the wet steam with reference to the detection signal, and the heat of at least one of the entrance opening and the exit opening And a heat loss compensator for compensating for the loss.

The present invention may have the following configuration as desired.
(2) In the above (1), the heat loss compensator includes a heat generation unit and a power supply unit, and the power supply unit generates electric power that can generate heat to compensate the heat loss in the heat generation unit. Supply.

(3) In the above (2), the heat generating part is a rubber heater in which a heating wire is laid.

(4) The rubber heater is provided around at least one of the entrance opening and the exit opening.

(5) In the above (3), the rubber heater is provided around at least one of the light incident part and the light receiving part.

(6) In the above (2), the heat generating portion is a transparent conductive film, and is provided on at least one opening surface of the entrance opening and the exit opening.

(7) In any one of the above (2) to (6), a temperature sensor is provided on at least one of the entrance opening and the exit opening, and the power supply unit is based on a detection signal of the temperature sensor. Electric power is supplied to the heat generating part so that the temperature of the opening surface is equal to or higher than the temperature of the wet steam.

(8) The wet steam pipe of the present invention is a pipe through which wet steam to be measured flows, an incident window through which light enters, an exit window through which light transmitted or reflected by the wet steam is emitted, and the detection signal , A dryness specifying unit that specifies the dryness of the wet steam, and a heat loss compensator that compensates for heat loss that occurs in at least one of the entrance window and the exit window.

In addition, not only the said objective but obtaining the solution means which has the solution principle shown in embodiment mentioned later can be positioned as one of the other objectives of this invention.

According to the present invention, since heat loss caused when measuring the dryness of wet steam by light is effectively compensated, the above-mentioned condensation and liquid phase stagnation are suppressed, and the dryness is measured with high accuracy. It is possible.

The schematic cross section explaining the composition of the dryness measuring apparatus concerning Embodiment 1 of the present invention. The schematic plan view of the rubber sheet which concerns on Embodiment 1 of this invention. The schematic cross section explaining the structure of the dryness measuring apparatus which concerns on Embodiment 2 of this invention (The injection opening side is abbreviate | omitted). The schematic cross section explaining the structure of the dryness measuring apparatus which concerns on Embodiment 3 of this invention (The injection opening side is abbreviate | omitted). The schematic cross section explaining the structure of the dryness measuring apparatus which concerns on Embodiment 4 of this invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the embodiment described below is merely an example, and there is no intention to exclude various modifications and technical applications that are not explicitly described below. In other words, the present invention can be implemented with various modifications (combining the embodiments, etc.) without departing from the spirit of the present invention. In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals. The drawings are schematic and do not necessarily match actual dimensions and ratios. In some cases, the dimensional relationships and ratios may be different between the drawings.

(Definition)
The main terms used in this specification are defined as follows.
“Vapor”: In each embodiment, it means water vapor, but it is not limited to water vapor as long as it is a vapor of a substance that is in a two-phase state of a gas phase portion and a liquid phase portion.
“Dryness”: Refers to the weight ratio of the vapor phase portion and the liquid phase portion in the vapor. There is a relationship of dryness [%] = 100 [%] − wetness [%].
“Wet steam”: refers to steam having a dryness χ of 0 to 100%.
“Light intensity” (light intensity): A physical quantity indicating the intensity of light (electromagnetic wave), and there is no limitation on its name or unit. For example, these are physical quantities that are mutually different but can be converted into each other, such as radiation intensity, luminous intensity, and photon flux density.

(Embodiment 1)
The first embodiment relates to a dryness measuring apparatus that measures the dryness of wet steam using a light entrance opening and / or an exit opening having a structure like a sight glass provided in a wet steam pipe.

(Constitution)
In FIG. 1, the schematic cross section explaining the structure of the dryness measuring apparatus which concerns on Embodiment 1 of this invention is shown. As shown in FIG. 1, the wet steam pipe 30 according to the first embodiment is a fluid flow passage through which the wet steam SA to be measured flows, and has a structure as a sight glass for transmitting light into the pipe 30. Prepare. Specifically, an entrance opening A1 and an exit opening A2 are provided on the side wall of the pipe 30. The entrance opening A <b> 1 and the exit opening A <b> 2 are provided at positions facing the axis of the pipe 30. An incident side cylinder 31 is connected to the incident opening A1, and an emission side cylinder 32 is provided at the emission opening A2. Flange 31f and 32f are formed in the edge of entrance side tube 31 and exit side tube 32, respectively, and tempered glass 33 and 34 are being fixed by a screw and other fixing means, respectively. Although not shown, a known heat insulating material such as glass wool is laid on the outer peripheral surface of the wet steam pipe 30 excluding the vicinity of the incident opening A1 and the injection opening A2, and in the region of the wet steam pipe 30 where the heat insulating material is laid, The heat loss to the outside is controlled slightly. With these sight glass structures, light is incident from the outside of the tempered glass 33 forming the end face of the incident side tube 31 while the inside of the pipe 30 is kept airtight, and is transmitted through the wet steam SA flowing through the pipe 30. It is possible to inject outward from the tempered glass 34 forming the end face of the injection side tube 32.

The pipe 30, the incident side tube 31, the emission side tube 32, etc. are made of a durable metal such as carbon steel, stainless steel, or other special materials. Such a sight glass is also called a flow sight. It is installed in the middle of a pipeline, and it is marketed as an instrument to directly monitor the flow, stop, and flow rate / flow rate of fluid passing through the pipeline. Commercial products are available.

Next, the configuration of the dryness measuring apparatus 1a according to the first embodiment will be described. As shown in FIG. 1, the dryness measuring apparatus 1 a includes a light incident part 11, a light receiving part 12, a dryness specifying part 13, and a heat loss compensator (20, 21, 22).

The light incident part 11 is a means for entering light of a predetermined wavelength into the incident side tube 31 from the entrance opening A1, that is, from the outside of the tempered glass 31, and even if it is a self-light emitting means for generating light itself, It may be a light guiding means for introducing light emitted from the light emitting means. For example, a light emitting diode, a super luminescent diode, a semiconductor laser, a laser oscillator, a fluorescent discharge tube, a low pressure mercury lamp, a xenon lamp, a halogen lamp, a metal halide lamp, an ultraviolet light source, an infrared light source, and a light bulb are used as the self-light emitting means. Although it is possible, it is not limited to the above as long as it can generate light having a stable wavelength and intensity. As the light guiding means, a plastic optical fiber made of polymethyl methacrylate resin (PMMA: Poly (methymethacrylate)), a glass optical fiber made of quartz glass, or the like can be used. The present invention is not limited to this as long as it has a function of propagating light emitted from the means.

The light receiving unit 12 is a light sensing unit that transmits the wet steam SA, receives the light emitted from the emission opening A2, that is, the emission side tube 32 through the tempered glass 32, and outputs a detection signal Sd. As the light receiving unit 12, for example, a photoelectric conversion element such as a photodiode or a phototransistor can be used. However, the light receiving unit 12 is limited to this as long as it can output a light reception signal Sd according to the intensity of light transmitted through the wet steam. Not.

The dryness specifying unit 13 is a calculation means for specifying the dryness χ of the wet steam SA by an arbitrary calculation method with reference to the detection signal Sd. The dryness specifying unit 13 is functionally realized by the computer device executing a predetermined software program for specifying the dryness. The computer device is, for example, a general-purpose computer including an input device, an output device, a program storage device, a temporary storage device, and a storage device, and the configuration thereof is not limited.

The calculation method of the dryness of the wet steam executed by the dryness specifying unit 13 can apply various known methods, and the calculation method is not limited. For example, the dryness specifying unit 13 refers to the light reception signal Sd, calculates the intensity of light transmitted through the wet steam SA, or a physical quantity related to the intensity of the light, and then stores the light intensity stored in advance in the storage device. Alternatively, a relationship table between physical quantities related to light intensity and dryness χ is referred to. Then, the dryness χ corresponding to the light intensity indicated by the light reception signal Sd or the physical quantity related to the light intensity is read and output as a measured value of the dryness χ. Instead of the relationship table, the dryness χ may be calculated based on a relational expression indicating the relationship between the light intensity or a physical quantity related to the light intensity and the dryness χ. In addition, the dryness specifying unit 13 may calculate the dryness χ while mutually referring to the light intensity obtained for each of the plurality of wavelengths of light or the physical quantity related to the light intensity.

The heat loss compensator is a means for compensating for heat loss that occurs in the entrance aperture A1 and the exit aperture A2. In the first embodiment, the heat loss compensator includes heat generating units (21, 22) and a power supply unit 20, and the heat generating units are specifically rubber heaters 21 and 22.

The rubber heater 21 is provided on the outer wall of the incident side tube 31 and heats the incident side tube 31 to compensate for heat loss generated on the incident opening A1 side. The rubber heater 22 is provided on the outer wall of the injection side tube 32 and heats the injection side tube 32 to compensate for heat loss generated on the injection opening A2 side. Hereinafter, the structure of the rubber heater 21 on the incident opening A1 side will be described, but the same applies to the rubber heater 22 on the injection opening A2 side.

FIG. 2 shows a plan view of the rubber heater 21. As shown in FIG. 2, the rubber heater 21 has a long rectangular shape in a belt shape, and is configured by laying a heating element 213 inside the rubber sheet 210. Hook fasteners 214 and 215 are attached to the end of the rubber sheet 210.

The rubber sheet 210 is an insulator having flexibility and constant thermal conductivity, and is made of, for example, silicon rubber. The material of the rubber sheet 210 is not limited to silicon rubber, and various materials can be applied as long as they satisfy flexibility, thermal conductivity, insulation, and durability. The rubber heater 21 is configured by sandwiching a heating element 213 between two rubber sheets 210 processed into a planar shape and bonding them with an adhesive or an adhesive film selected according to the operating temperature.

The heating element 213 is a linear or planar heating means that has lead wires 211 and 212 attached to both ends and generates heat when power is supplied from the lead wires 211 and 212. As the heating element 213, a general electrothermal material capable of converting current into heat quantity can be applied, and for example, carbon or nickel alloy resistance wire can be applied.

The hook-and- loop fasteners 214 and 215 have a function of generating an adhesive force when they are brought into contact with each other, and can be detachably locked at a portion to which each hook-and-loop fastener is attached. For example, one of the hook-and- loop fasteners 214 and 215 is a surface raised in a hook shape, and the other is a surface raised in a loop shape. The hook-and-loop fastener 214 is attached with the raised surface facing the surface side at the end of the surface of the rubber sheet 210. The hook-and-loop fastener 215 is attached at the end of the back surface of the rubber sheet 210 with the raised surface facing the back surface. The hook-and- loop fasteners 214 and 215 are optional configurations, and instead of the hook-and-loop fastener, the rubber sheet 210 is fastened from the outside with a string-like member or a band-like member, or the end of the rubber sheet 210 is bonded with an adhesive or the like. The rubber heater 21 may be attached to the incident side tube 33.

The rubber heater 21 is processed so as to have a width d1 in the longitudinal direction of the band and a width d2 in the width direction of the band. The width d1 in the longitudinal direction is such that when the rubber sheet 210 is wound around the outer periphery of the incident side tube 31, the hook-and- loop fasteners 214 and 215 are not loosened while the inner surface of the rubber sheet is in contact with the outer peripheral surface of the incident side tube 31. Adjust the length so that they can touch each other. The width d2 in the short direction is adjusted to correspond to the height of the outer periphery of the incident side tube 31, that is, the width from the outer wall of the pipe 30 to the rear surface of the flange 31f. When the shapes of the incident side cylinder 31 and the emission side cylinder 32 are different, the width d1 and the width d2 of the rubber heater 22 are adjusted so that the rubber heater 22 matches the shape of the emission side cylinder 32.

Referring back to FIG. 1, the power supply unit 20 is configured to be able to supply power that can generate heat that compensates for heat loss in the heat generating unit. Specifically, the power supply unit 20 is connected to the lead wires 211 and 212 from the rubber heater 21, and applies a predetermined voltage between the lead wires, whereby the heating power D <b> 1 is generated from the heating element 213 of the rubber heater 21. Can be supplied. The power supply unit 20 is connected to the lead wires 211 and 212 from the rubber heater 22, and can apply a predetermined voltage between the lead wires to supply the heating power D <b> 2 to the heating element 213 of the rubber heater 22. It has become. The power supplied by the power supply unit 20 is set to such an amount that the heat generation unit (rubber heaters 21 and 22) generates a heat quantity that can compensate for heat loss that occurs near the entrance opening A1 and the exit opening A2. Such electric power is, for example, near the entrance opening A1 (specifically, the inner wall surface of the tempered glass 33 and the entrance side tube 31) or near the exit opening A2 (specifically, the tempered glass 34 and the exit side tube 32). It can be obtained by experimentally specifying electric power that does not condense the wet steam SA on the inner wall surface or stagnate the liquid phase.

(Function)
Next, the operation of the first embodiment will be described.
When the wet steam SA is supplied to the wet steam measurement pipe 30, the power supply unit 20 supplies the heating powers D1 and D2 to the rubber heaters 21 and 22 that are the heat generating parts. In the rubber heaters 21 and 22, the heating element 213 receives the heating power and generates heat, and the heat is transmitted to the incident side tube 31 and the emission side tube 32. A heat insulating material cannot be provided in the vicinity of the entrance opening A1 and the exit opening A2, in particular, outside the tempered glass 33 and the tempered glass 34. Therefore, a slight heat loss occurs, but the amount of heat sufficient to compensate for the heat loss is rubber. Supplied from heaters 21 and 22. As a result, the phenomenon that aggregation occurs in the wet steam SA or the liquid phase stagnates is suppressed.

At the time of measurement, light is irradiated from the light incident part 11 into the incident side tube 31 through the tempered glass 33 toward the wet steam SA flowing inside the wet steam pipe 30. Light that has passed through the wet steam SA flowing through the center of the wet steam pipe 30 from the inside of the incident side pipe 31 enters the emission side pipe 32 on the opposite side of the pipe 30 and is emitted through the tempered glass 34. The emitted light is received by the light receiving unit 12 and outputs a light reception signal Sd corresponding to the intensity of the light transmitted through the wet steam SA or a physical quantity related to the intensity of the light.

The dryness specifying unit 13 refers to the received light reception signal Sd and specifies the dryness χ by a predetermined calculation method. The specified dryness χ is output to an output device provided in the dryness specifying unit 13. This output form may be output information display, printing, or data transmission.

(effect)
According to the first embodiment described above, when the wet steam pipe 30 is provided with a measurement structure as a sight glass, the power supply unit 20 performs heating to compensate for the amount of heat lost near the entrance opening A1 and the exit opening A2. Electric power D1 and D2 are supplied, and rubber heaters 21 and 22 provided on the outer circumferences of the incident side cylinder 31 and the emission side cylinder 32 compensate for heat loss. Therefore, it can suppress that wet steam SA condenses near a sight glass, or a liquid phase stagnates, and can prevent the deterioration of the precision of dryness measurement.

According to the first embodiment, since the rubber heaters 21 and 22 are applied as the heat generating portions, it is easy to process into a shape suitable for the shapes of the incident side tube 31 and the emission side tube 32.

(Embodiment 2)
Embodiment 2 of the present invention relates to a heat generating portion applied to a light incident portion having a form like an optical fiber.

(Constitution)
In FIG. 3, the structure of the dryness measuring apparatus 1b in this Embodiment 2 is shown. As shown in FIG. 3, the wet steam pipe 30 according to the second embodiment has a structure in which a head portion of an optical fiber can be inserted into the incident opening A1 instead of the incident side tube. 11b differs from the first embodiment in that it has an optical fiber structure.

In addition, about the injection | emission opening A2, it is possible to set it as the light reception structure by the side of the injection | emission opening A2 of the said Embodiment 1. FIG. In the case where a light receiving means such as an optical probe is provided in the exit aperture A2, a structure corresponding to an optical fiber similar to the entrance aperture A1 side may be adopted.

The dryness measuring apparatus 1b in the second embodiment is different from the first embodiment in the structure of the light incident part 11b and the structure of the heat generating part applied to the light incident part 11b, and the other structures are the same as in the above embodiment. is there. In FIG. 3, a schematic cross section near the entrance opening A1 including the light entrance portion 11b is shown, and the configuration on the exit opening A2 side is omitted.

As shown in FIG. 3, the light incident portion 11 b is means for causing light of a predetermined wavelength to enter the wet steam pipe 30 from the incident opening A <b> 1, and includes an optical fiber head 110, a condensing lens 111, and an optical fiber cable 112. , A light emitting unit 113, and a light emitting power supply unit 114. A rubber heater 21b is provided.

The light emitting power supply unit 114 is a driving unit that supplies predetermined power to the light emitting unit 113 to cause the light emitting unit 113 to emit light with a light amount sufficient to measure the dryness of wet steam. The power supplied to the light emitting unit 113 is an amount of power corresponding to the specification of the light emitting unit 113. When power is supplied with alternating current, power is further supplied with a frequency and voltage waveform according to the specifications of the light emitting unit 113.

The light emitting unit 113 is a self-light emitting means for generating light itself. For example, a light emitting diode, a super luminescent diode, a semiconductor laser, a laser oscillator, a fluorescent discharge tube, a low pressure mercury lamp, a xenon lamp, a halogen lamp, a metal halide lamp, an ultraviolet ray A light source, an infrared light source, a light bulb, and the like can be used, but are not limited to the above as long as they can generate light having a stable wavelength and intensity.

The optical fiber cable 112 is a light guiding unit that transmits light output from the light emitting unit 113. As the optical fiber cable 112, for example, a plastic optical fiber made of polymethyl methacrylate resin (PMMA: Poly (methyl methacrylate)), a glass optical fiber made of quartz glass, or the like can be used. However, the present invention is not limited to this as long as it has a function of propagating light.

The optical fiber head 110 is a container that houses the tip of the optical fiber cable 112 for a predetermined length, and includes a condenser lens 111 at the tip. The optical fiber head 110 blocks external light, connects the internal optical fiber cable 112 and the condenser lens 111 optically without loss, and connects the optical fiber cable 112 and the condenser lens 111 physically and chemically. To protect. For this reason, the optical fiber head 110 is preferably made of a chemically stable material having mechanical strength such as metal or resin.

As shown in FIG. 3, in the second embodiment, the entrance opening A1 of the wet steam pipe 30 has a diameter that matches the tip diameter of the optical fiber head 110, and the tip of the optical fiber head 110 is the entrance opening A1. It is being fixed in the state inserted in the piping 30. The optical fiber head 110 may protrude from the entrance opening A1 to the back of the pipe 30 within a range that does not affect the flow of the wet steam SA.

In the second embodiment, a rubber heater 21b and a power supply unit 20 (not shown) are provided as a heat loss compensation device that compensates for heat loss generated in the incident aperture A1. The power supply unit 20 is the same as the power supply unit 20 in the first embodiment, and a description thereof will be omitted.

The rubber heater 21b is a heat generating portion provided so as to cover the outer periphery in the vicinity of the tip of the optical fiber head 110, and the detailed structure except for the overall dimensions has been described with reference to FIG. The same as the rubber heater 21. That is, as described in the first embodiment, the rubber heater 21b has a structure in which the heating element 213 is provided inside a rubber sheet having a long rectangular band shape, and supplies power to the heating element 213. Lead wires 211 and 212 are provided, and the lead wires 211 and 212 are connected to the power supply unit. Surface fasteners 214 and 215 are attached to the end of the rubber heater 21b. The rubber fastener 21b is attached to the optical fiber head 110 by winding the surface fasteners 214 and 215 around the outer periphery of the optical fiber head 110. The outer periphery of 110 can be tightly fixed. In FIG. 3, the heating element 213 and the hook-and- loop fasteners 214 and 215 are not shown.

The width d1 in the longitudinal direction of the rubber heater 21b is such that when the rubber heater 21b is wound around the outer periphery of the optical fiber head 110, the inner surface of the rubber sheet is in contact with the outer peripheral surface of the optical fiber head 110 without looseness. The length is adjusted such that 214 and 215 can be brought into contact with each other. The width in the short direction of the rubber heater 21b is adjusted so that an area capable of transmitting a sufficient amount of heat to the optical fiber head 110 can be supplied.

(Function)
Next, the operation of the second embodiment will be described.
When the wet steam SA is supplied to the wet steam measurement pipe 30, the power supply unit 20 supplies the heating power D1 to the rubber heater 21b, which is a heat generating part. In the rubber heater 21b, the heating element 213 receives the heating power and generates heat, and the heat is transmitted to the optical fiber head 110. For this reason, although a heat insulating material cannot be provided in the vicinity of the incident aperture A1, a slight heat loss occurs. However, an amount of heat sufficient to compensate for the heat loss is supplied from the rubber heater 21b. Therefore, it is possible to prevent the wet steam SA from condensing near the tip of the optical fiber head 110 and the liquid phase from stagnation, and it is possible to prevent deterioration in accuracy of dryness measurement.

(effect)
According to the second embodiment described above, when the light incident portion has an optical fiber structure, the power supply portion 20 supplies the heating power D1 that compensates for the amount of heat lost near the entrance opening A1, and the outer periphery of the optical fiber head 110 is supplied. Since the provided rubber heater 21b compensates for heat loss, it is possible to prevent the wet steam SA from condensing in the vicinity of the incident aperture A1 and the liquid phase from stagnation, and it is possible to prevent deterioration in accuracy of dryness measurement.

(Embodiment 3)
Embodiment 3 of the present invention relates to a modified example of the heat generating portion in which a transparent conductive film is provided in an incident opening.

(Constitution)
In FIG. 4, the schematic cross section explaining the structure of the dryness measuring apparatus which concerns on Embodiment 3 of this invention is shown. As shown in FIG. 4, the wet steam pipe 30 applied in the third embodiment has the same sight glass structure as in the first embodiment. For the sake of simplicity, FIG. 4 shows only the structure on the incident aperture A1 side, and omits the structure on the exit aperture A2 side. On the exit aperture A2 side, a structure similar to that on the entrance aperture A1 side may be provided.

As shown in FIG. 4, the dryness measuring apparatus 1 c according to the third embodiment is a transparent film heater 21 c and a power supply unit 20 (not shown) as a heat loss compensator that compensates for heat loss generated in the incident aperture A <b> 1. Is provided. The power supply unit 20 is the same as the power supply unit 20 in the first embodiment, and a description thereof will be omitted.

The transparent film heater 21c is a transparent conductive film that rises to a predetermined temperature and maintains the temperature when a predetermined voltage is applied through the lead wires 211 and 212, and generates heat having a predetermined sheet resistance. Part. The sheet resistance range may be any resistance value suitable for heat generation in relation to the applied voltage, and is not limited, but is, for example, in the range of several thousand Ω / □ to several tens of Ω / □. The transparent conductive film has a layer structure in which a transparent conductive material layer is formed on a substrate and a protective layer is formed thereon. The base material is a resin film (for example, PET, PPS, PI film, etc.) that has optical transparency and can be bonded to the tempered glass 33. As the transparent conductive material layer, a conductive material that is light transmissive and has a certain sheet resistance can be applied. For example, a self-assembled film made of carbon nanotubes (CNT), ITO, or nano-sized metal (Ag, etc.), a film in which a metal (for example, Ag, etc.) that adjusts resistance is scattered on ITO, etc. can be applied. Further, the transparent film heater 21c may be a film obtained by patterning a large number of resistance lines having a fine width on a substrate. The transparent film heater 21c is bonded to the tempered glass 33 with an adhesive or an adhesive film. The transparent film heater 21 c is shaped to a size adapted to the size of the tempered glass 33.

(Function)
Next, the operation of the third embodiment will be described.
When the wet steam SA is supplied to the wet steam measurement pipe 30, the power supply unit 20 supplies the heating power D <b> 1 via the lead lines 211 and 212 to the transparent film heater 21 c that is a heat generating part. The transparent film heater 21c generates heat by receiving the supply of the heating power D1, thereby heating the surface of the tempered glass 33 to a temperature that is the same as or slightly higher than the temperature of the wet steam SA in the pipe 30, for example, 170 ° C. As a result, an amount of heat sufficient to compensate for the heat loss generated on the incident aperture A1 side is generated. Therefore, it is possible to prevent the wet steam SA from condensing near the back surface of the tempered glass or the liquid phase from stagnation, and it is possible to prevent deterioration in accuracy of dryness measurement.

(effect)
According to the third embodiment described above, the power supply unit 20 supplies power to compensate for the amount of heat lost near the entrance opening A1, and the transparent film heater 21c provided on the surface of the tempered glass 33 compensates for heat loss. In addition, it is possible to prevent the wet steam SA from condensing near the back surface of the tempered glass 33 and the liquid phase from stagnation, and it is possible to prevent deterioration in accuracy of dryness measurement.

Particularly, according to the third embodiment, since the transparent film heater 21c generates heat by covering the surface of the tempered glass where heat loss is likely to occur, heat loss at the opening surface can be compensated efficiently.

(Embodiment 4)
Embodiment 4 of the present invention relates to a dryness measuring apparatus in which a temperature sensor is provided on an opening surface of an incident opening.

(Constitution)
In FIG. 5, the structure of the dryness measuring apparatus 1d in this Embodiment 4 is shown. As shown in FIG. 5, the dryness measuring apparatus 1d according to the fourth embodiment includes the temperature sensor 23 on the surface of the tempered glass 33 on the incident opening A1 side. This is different from the first embodiment in that the temperature sensor 24 is provided on the surface of the tempered glass 34 on the injection opening A2 side. Since other configurations are the same as those in the first embodiment, description thereof is omitted.

The temperature sensor 23 is a detection unit that measures the surface temperature of the tempered glass 33 and outputs a detection signal S1 indicating the measured temperature to the power supply unit 20. The temperature sensor 24 is a detection unit that measures the surface temperature of the tempered glass 34 and outputs a detection signal S2 indicating the measured temperature to the power supply unit 20. The temperature sensors 23 and 24 are not limited in form as long as the temperature of the tempered glass surface can be measured. In order to measure the temperature of the glass surface and output a detection signal which is an electric signal, the temperature sensors 23 and 24 are contact type and electric type temperature detection means such as a resistance temperature detector (RTD), a linear resistor. A thermistor, a thermocouple, an IC temperature sensor, etc. can be applied. The temperature sensors 23 and 24 are preferably small so as not to block light when provided on the surface of the tempered glass.

In the fourth embodiment, the power supply unit 20 receives the detection signal S1 from the temperature sensor 23 and supplies the detection signal S1 to the rubber heater 21 so that the surface temperature of the tempered glass 33 is maintained near the temperature of the wet steam SA. The heating power D1 is controlled. Further, the power supply unit 20 receives the detection signal S2 from the temperature sensor 24, and controls the heating power D2 supplied to the rubber heater 22 so that the surface temperature of the tempered glass 34 is maintained near the temperature of the wet steam SA. Is configured to do.

(Function)
Next, the operation of the fourth embodiment will be described.
When the wet steam SA is supplied to the wet steam measurement pipe 30, the power supply unit 20 controls the heating power D <b> 1 supplied to the rubber heater 21 based on the detection signal S <b> 1 from the temperature sensor 23. The power supply unit 20 controls the heating of the power D2 supplied to the rubber heater 22 based on the detection signal S2 from the temperature sensor 24.

For example, when the surface temperature of the tempered glass is lower than the temperature of the wet steam SA, the power supply unit 20 supplies power by applying a predetermined voltage between the lead wires 211 and 212 of the rubber heater 21 (22), When the surface temperature of the tempered glass reaches the temperature of the wet steam SA, the power supply is stopped.

As a modification, the power supply unit 20 may change the heating power supplied to the rubber heater 21 (22) stepwise or gradually. For example, the power supply unit 20 gradually applies a voltage to be applied between the lead wires 211 and 212 of the rubber heater 21 (22) in accordance with the magnitude of the difference between the surface temperature of the tempered glass and the temperature of the wet steam SA. Alternatively, the heating power to be supplied may be controlled to gradually decrease and gradually decrease or gradually decrease. In this way, by gradually or gradually reducing the power supplied to the heat generating part, it is possible to prevent the measured value of the dryness from becoming inaccurate due to overheating of the tempered glass. .

(effect)
According to the fourth embodiment described above, the power supply unit 20 controls the power supplied to the rubber heater 21 (22) based on the detection signal S1 (S2) of the temperature sensor 23 (24). It is possible to supply the necessary and sufficient power to make up for the amount of heat lost.

Particularly, according to the fourth embodiment, since the heating temperature is suppressed from becoming higher than the temperature of the wet steam SA, it is possible to prevent the measurement value of the dryness from being inaccurate due to the influence of overheating.

(Other variations)
The present invention is not limited to the above-described embodiment, and can be variously modified and applied.

(1) For example, in Embodiment 1 and Embodiment 4 described above, the rubber heater 21 (22) is provided as a heat generating part in both the incident side cylinder 31 on the incident opening A1 side and the emission side cylinder 32 on the emission opening A2 side. In the case of a structure with little heat loss in one of the openings, the heat generating portion on the opening side with little heat loss may be omitted.

(2) In Embodiment 2 and Embodiment 3 described above, only the structure of the heat generating portion on the incident opening A1 side is described, but when the heat loss from the exit opening A2 side is large, the heat generating portion can be provided, If the heat loss is small, the heat generating part may be omitted.

(3) In the above embodiment, an example of a specific dryness measurement method of the dryness measurement device has been described. However, the present invention is not limited to the above, and various dryness measurement methods can be applied. When measuring the dryness, it is possible to measure the pressure or / and temperature inside the pipe 30 and calculate and specify not only the intensity of light transmitted through the wet steam SA but also as a function of the pressure and temperature of the wet steam. It is.

(4) In the above embodiment, the dryness is calculated based on the intensity of light that passes through the wet steam SA or a physical quantity related to the intensity of light, but the intensity of light reflected by the wet steam SA or the light intensity You may comprise so that a dryness may be calculated based on the physical quantity relevant to intensity | strength. Since the intensity of light transmitted through the wet steam correlates with the intensity of light reflected by the wet steam, the dryness degree based on the intensity of light reflected by the wet steam is determined by a predetermined conversion calculation. It can be applied to properties. When the dryness is calculated based on the light reflected by the wet steam, the light incident part and the light receiving part are provided in the same opening to reduce heat loss from the pipe itself, It is possible to reduce the cost by providing only one location near the shared opening.

Industrial application fields

The dryness measuring device of the present invention can be applied to heavy and large industrial fields. In this field, since the dryness of the wet steam at the steam turbine outlet depends on the power generation efficiency, the flow rate at the turbine inlet can be controlled according to the load by accurately measuring the dryness at the turbine outlet. Heat loss can be reduced.

1a, 1b, 1c, 1d Wet steam measuring device 11, 11b Light incident unit 12 Light receiving unit 13 Dryness specifying unit 20 Power supply unit 21, 22, 21b Rubber heater 21c Transparent film heater 23, 24 Temperature sensor 30 Wet steam piping (pipe)
31 Incident side tube 32 Ejection side tube 31f, 32f Flange 33, 34 Tempered glass 110 Optical fiber head 111 Condensing lens 112 Optical fiber cable 113 Light emitting unit 114 Light emission power supply unit 210 Rubber sheet 211, 212 Lead wire 213 Heating element 214, 215 hook-and-loop fastener A1 entrance opening A2 exit opening SA wet steam D1, D2 supply power S1, S2, Sd detection signal

Claims (8)

1. A light incident part for allowing light to enter from an incident opening provided in a pipe through which wet steam to be measured flows;
   A light receiving unit that receives light transmitted through or reflected from the wet steam from an injection opening provided in the pipe and outputs a detection signal;
   A dryness specifying unit that specifies the dryness of the wet steam with reference to the detection signal;
   A heat loss compensator that compensates for heat loss of at least one of the entrance aperture and the exit aperture, and
   Dryness measuring device.
2. The heat loss compensator has a heat generating part and a power supply part,
   The power supply unit supplies power that can generate heat to compensate the heat loss to the heat generating unit.
   The dryness measuring apparatus according to claim 1.
3. The heating unit is a rubber heater in which a heating wire is laid.
   The dryness measuring apparatus according to claim 2.
4. The rubber heater is provided around at least one of the entrance opening and the exit opening.
   The dryness measuring apparatus according to claim 3.
5. The rubber heater is provided around at least one of the light incident part and the light receiving part.
   The dryness measuring apparatus according to claim 3.
6. The heat generating part is a transparent conductive film,
   Provided on at least one opening surface of the entrance opening and the exit opening,
   The dryness measuring apparatus according to claim 2.
7. A temperature sensor is provided on at least one of the entrance opening and the exit opening;
   The power supply unit supplies power to the heating unit such that the temperature of the opening surface is equal to or higher than the temperature of the wet steam based on a detection signal of the temperature sensor.
   The dryness measuring apparatus according to any one of claims 2 to 6.
8. A pipe through which wet steam to be measured flows,
   An incident window through which light is incident;
   An exit window for emitting light transmitted or reflected from the wet steam;
   A dryness specifying unit that specifies the dryness of the wet steam with reference to the detection signal;
   A heat loss compensator that compensates for heat loss that occurs in at least one of the entrance window and the exit window,
   Wet steam piping.

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