JP2014059117A - Reflection mirror for heliostat, heliostat and method of producing reflection mirror for heliostat - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a reflection mirror for a heliostat having an improved durability as compared to the conventional reflection mirror for a heliostat.SOLUTION: A reflection mirror 10 for a heliostat includes: a reflection mirror 18 with a protective layer which has a reflection layer 14 formed on substantially the whole surface on a back surface of a transparent substrate 12 and has a protective layer 16 formed on substantially the whole surface on the reflection layer 14; and a protective plate 22 having non-gas permeability and non-water permeability which overlaps substantially the whole surface of the back surface of the reflection mirror 18 with the protective layer and is adhered to substantially the whole surface of the back surface of the reflection mirror 18 with the protective layer with an adhesive 20. The reflection mirror 18 with the protective layer, for example, can be configured with an ordinary silver mirror offered commercially.

Description

  The present invention relates to a heliostat reflector and a heliostat using the heliostat reflector, which has improved durability compared to the conventional one. The present invention also relates to a method of manufacturing the heliostat reflector.

  A heliostat is a device that supports a reflecting mirror so that it can be displaced following the movement of the sun, and sends sunlight reflected by the reflecting mirror to a predetermined target position. A solar condensing device that uses a plurality of heliostats to condense on a predetermined condensing target is used for solar thermal power generation, solar lighting, and the like.

  Heliostat reflectors may be composed of silver mirrors to obtain high reflectivity. A silver mirror is generally configured by sequentially laminating a silver layer and a protective layer (for example, a copper layer + a coating layer) on the back surface of a glass substrate. Since heliostats are usually used in harsh outdoor environments with high temperatures, if the reflector is composed of a silver mirror, the silver layer may corrode and deteriorate during use, and the reflectivity may decrease. . Therefore, silver mirrors used in heliostats are required to have a high degree of durability.

  As a silver mirror used in a heliostat or the like, a silver mirror with improved durability is described in Patent Document 1 below. This silver mirror “puts the glass substrate in the exhaust chamber so that it substantially removes oxygen from the surface of the glass substrate and substantially protects the surface from impurities and contaminants. The substrate surface is enriched with silicon atoms, and silver atoms are coated on the silicon-enriched surface of the glass substrate in the exhaust chamber, thereby providing sufficient strength and durability to withstand degradation caused by terrestrial environmental conditions. It provides a bond between a silicon atom and a silver atom having a structure ”(claim 1). In Patent Document 1, “copper and impurities from the copper layer, and further impurities from the paint layer, etc., accelerate the deterioration of the silver layer” coated on the silver layer ”(page 4, lower right column, item 6). Based on the knowledge of ˜8 lines), as a countermeasure, “a copper or paint layer having a harmful effect on the silver layer is not used. For example, as shown in FIG. Layer 51 can be laminated, so that the silver layer is sandwiched between glass substrate 42 and glass layer 51 "(page 7, lower left column, line 16 to the lower right column, first line). Propose that.

JP 61-266334 A (FIG. 16) Japanese Patent Laying-Open No. 2011-197668 (FIG. 6)

  Since the reflecting mirror described in FIG. 16 of Patent Document 1 has a structure in which a thin glass layer (51) is directly laminated on a silver layer (50), the thin glass layer (51) is vacuum-deposited in a vacuum chamber. There is a problem that the manufacturing cost becomes high. In addition, since it takes a long time to form a thick glass layer by vacuum evaporation or the like, the thin glass layer (51) must inevitably be quite thin from the viewpoint of work efficiency, and the strength is weak. was there. In a relatively small heliostat having a reflector area of, for example, 2 square meters or less, the reflector may be fixed to the reflector mounting structure (metal frame, etc.) of the heliostat with an adhesive (for example, The reflecting mirror described in FIG. 16 of Patent Document 1) is obtained by bonding the thin glass layer (51) to the reflecting mirror mounting structure of the heliostat with an adhesive. When receiving stress from the mounting structure, the thin glass layer (51) was easily cracked due to insufficient strength and peeled off from the reflecting mirror. As a result, the reflecting mirror could fall off the heliostat. In the technique described in Patent Document 2, when a reflector having a protective layer on the back surface of the reflective layer is bonded to the reflector mounting structure of the heliostat with an adhesive, “the protective layer and the mirror structure are caused by temperature fluctuation, mechanical stimulation, etc. Based on the knowledge that the adhesive structure with the body is weak and the mirror is peeled off from the mirror structure ”(2nd page, 0004 stage), the solution is“ the mirror 3 is on the surface side of the transparent glass substrate 3a. A reflective layer 3b made of silver or the like is formed, and a cross-sectional structure having a transparent protective film 3c is formed on the reflective layer 3b, and substantially the entire surface of the support plate 4 is bonded to the back surface of the mirror 3. Adhesion is strong because the object to be bonded is the hard transparent glass substrate 3b ”(4th page, 0025, FIG. 6) (that is, the reflective layer is formed on the front surface side of the substrate). Use a surface mirror) It is draft. However, in this structure described in Patent Document 2, since the surface of the reflective layer (3b) is only covered with the transparent protective film (3c), when the reflective layer (3b) is composed of a silver layer, the reflective layer ( The durability (weather resistance) of 3b) is low, and the silver layer corrodes and deteriorates during use, and it is expected that the reflectivity rapidly decreases with time.

  The present invention is intended to solve the above-described problems in the prior art, and to provide a heliostat reflecting mirror having improved durability compared to the conventional one, and a heliostat using this heliostat reflecting mirror. is there. Another object of the present invention is to provide a method for manufacturing the reflector for the heliostat.

  The heliostat reflector according to the present invention includes a reflector with a protective layer in which a reflective layer is formed on the back surface of a transparent substrate and a protective layer is formed on the reflective layer, and an adhesive on the back surface of the reflector with the protective layer. A non-breathable and non-water-permeable protective plate. According to the inventor's weather resistance experiment (described later) using a reflector for heliostats according to the present invention in which a glass plate is bonded to the back surface of a normal silver mirror as a protective plate, the degradation of the reflective layer due to corrosion is suppressed. It has been found that sufficient durability (weather resistance) can be obtained as a reflecting mirror for a stat. It is presumed that the protective plate made of the glass plate sufficiently blocks moisture and oxygen in the environment and suppresses the corrosion of the reflective layer. The same effect can be expected when a plate made of another inorganic material such as a ceramic plate, a metal plate, a ceramic coated metal plate, or a resin plate having high weather resistance such as PMMA is used as the protective plate. Therefore, a reflector having a special structure such as a reflector having a bond between silicon atoms and silver atoms described in FIG. 16 of Patent Document 1 is not necessary, and a commercially available protective layer is provided. It can be made of an inexpensive material using a reflector. If the transparent substrate and the protective plate are made of the same material (for example, glass), the thermal expansion coefficient of the transparent substrate and the protective plate can be made equal or nearly equal, and the curvature of the reflective layer that occurs when the thermal expansion coefficients differ greatly In addition, the deterioration of the adhesive due to the stress between the two plates can be suppressed. Moreover, since there is a protective layer between the reflective layer and the adhesive layer, direct contact between the reflective layer and the adhesive is prevented, and deterioration of the reflective layer due to the adhesive can be suppressed.

  Further, according to the reflector for heliostats of the present invention, the reflective layer is covered and protected by the protective layer before the protective plate is adhered, and the adhesion between the reflective mirror with the protective layer and the protective plate is performed in a non-vacuum atmosphere. Since it can be performed (for example, in an air atmosphere), it is not necessary to form a glass layer in the vacuum chamber unlike the reflecting mirror described in FIG. 16 of Patent Document 1, and the manufacturing cost can be reduced. Moreover, in order to prevent corrosion of the silver layer (50) exposed to the surrounding environment before forming the thin glass layer (51), the reflecting mirror described in Patent Document 1 It is necessary to perform the formation and the formation of the thin glass layer (51) in a continuous process. On the other hand, according to the reflector for heliostats of the present invention, since the reflective layer is covered and protected by the protective layer before the protective plate is adhered, the production of the reflective mirror with the protective layer and the adhesion of the protective plate are performed. Need not be performed in a continuous process. Therefore, the protective plate can be bonded to a reflecting mirror with a protective layer purchased from the outside.

  Further, according to the heliostat reflecting mirror of the present invention, since the protective plate can be easily obtained with a thickness larger than that of the thin glass layer described in Patent Document 1, the protective plate can be obtained more easily than the thin glass layer described in Patent Document 1. The strength can be easily increased. Therefore, compared with the thing of patent document 1, durability can also be improved easily also in terms of mechanical strength. As a result, even when the protective plate is bonded to the heliostat reflector mounting structure with an adhesive, when the heliostat reflector receives stress from the reflector mounting structure, the protective plate Cracking due to insufficient strength can be prevented, and the heliostat reflector can be prevented from falling off the heliostat. Further, the rigidity of the heliostat reflector as a whole can be enhanced by adhering a protective plate to the reflector with the protective layer. Therefore, it is possible to suppress bending due to the weight of the heliostat reflector. Further, since the rigidity can be increased by the protective plate, the transparent substrate of the reflecting mirror with the protective layer can be made thin, and thereby the reflectance of the reflecting mirror with the protective layer can be increased.

  In the heliostat reflector according to the present invention, for example, the protective plate may cover substantially the entire surface of the protective layer. According to this, the protective layer can be substantially shielded from the outside air over the entire surface, and deterioration due to corrosion of the reflective layer can be suppressed.

  In the heliostat reflector according to the present invention, for example, the protective plate may be bonded to the protective layer over substantially the entire surface facing the protective layer. According to this, the adhesive strength between the reflecting mirror with the protective layer and the protective plate can be increased.

  In the reflector for heliostats according to the present invention, for example, the reflective layer may have a silver layer, and the protective layer may have a copper layer and a coating layer formed on the copper layer. According to this, as a reflecting mirror with a protective layer, a commercially available general silver mirror can be used at low cost.

  The heliostat according to the present invention includes a reflecting mirror for the heliostat according to the present invention, a reflecting mirror mounting structure bonded to the back surface of the reflecting mirror for the heliostat with an adhesive, and the reflecting mirror mounting structure for moving the sun. And a reflecting mirror support mechanism for following and supporting the displacement. As described above, the protective plate of the reflector for heliostats of the present invention can be easily obtained with a strength higher than that of the thin glass layer described in Patent Document 1. Therefore, according to the heliostat of the present invention, the heliostat When the reflector is subjected to stress from the reflector mounting structure, the protective plate is prevented from cracking due to insufficient strength at the location where the protective plate is adhered to the reflector mounting structure of the heliostat with an adhesive. It is possible to prevent the heliostat reflector from falling off the heliostat.

  The method for manufacturing a reflector for heliostats according to the present invention includes a step of preparing a reflector with a protective layer in which a reflective layer and a protective layer are sequentially formed on the back surface of a transparent substrate; And a step of adhering a protective plate having air permeability and water permeability with an adhesive. According to this, a reflector having a special structure such as a reflector having a bond between a silicon atom and a silver atom described in Patent Document 1 is not necessary, and a commercially available reflector with a protective layer is commercially available. Can be made of cheap material using a mirror. In addition, since the reflective layer of the reflective mirror with the protective layer is protected by the protective layer before bonding the reflective mirror with the protective layer and the protective plate, the adhesive between the reflective mirror with the protective layer and the protective plate is in a non-vacuum atmosphere ( For example, in an air atmosphere). Therefore, it is not necessary to form the glass layer in the vacuum chamber as in the technique described in Patent Document 1, and the manufacturing cost can be reduced.

It is a figure which shows embodiment of the reflective mirror for heliostats of this invention, and is sectional drawing which showed typically the layer structure of this reflective mirror. It is a rear view which shows embodiment of the heliostat provided with the reflective mirror of FIG. FIG. 3 is a side view of the heliostat of FIG. 2. The line graph showing the experimental results of the weather resistance experiment with the heliostat reflector (silver mirror) according to the present invention and other silver mirrors shows the time-varying characteristics of the reflectance.

  Embodiments of the present invention will be described below. The heliostat reflector 10 shown in FIG. 1 is a reflective layer with a protective layer in which a reflective layer 14 is formed on substantially the entire back surface of the transparent substrate 12 and a protective layer 16 is formed on substantially the entire surface of the reflective layer 14. An adhesive such as an epoxy that covers substantially the entire back surface of the mirror 18 and the reflecting mirror 18 with the protective layer and has substantially no air permeability and water permeability on the entire back surface of the reflecting mirror 18 with the protective layer 20 is provided with a non-breathable and water-impermeable protective plate 22 bonded at 20. The transparent substrate 12 of the reflective mirror 18 with the protective layer is a transparent glass plate having an area of, for example, 2 square meters or less and a thickness of, for example, 4 mm. The reflecting mirror 18 with a protective layer can be comprised with the common silver mirror marketed, for example. For example, the protective plate 22 can be formed of a glass plate having a thickness of 1 mm. The outer edge surface (side surface) 23 of the reflecting mirror 10 for heliostat is substantially entirely sealed with a sealing material (for example, an epoxy-based sealing resin) 24 having air permeability and water permeability. The transparent substrate 12 is composed of a transparent glass substrate, for example. The reflective layer 14 is composed of, for example, a silver layer. The protective layer 16 is composed of, for example, a two-layer film of a copper layer 26 laminated on the reflective layer 14 and a coating layer 28 laminated on the copper layer 26. A heliostat reflector mounting structure 30 (for example, a metal frame such as aluminum) is bonded to the center of the front surface of the protective plate 22 on the back surface of the heliostat reflector 10 with an adhesive 32. Even if the bonding area between the reflecting mirror mounting structure 30 and the protection plate 22 is a part of the entire surface of the protection plate 22, if the protection plate 22 is thick and strong, the heliostat reflection mirror 10 is used as the reflection mirror. When stress is received from the mounting structure 30, the stress is prevented from concentrating on the adhesion region of the protective plate 22, and the protective plate 22 is prevented from cracking, and the heliostat reflector 10 is dropped from the heliostat. Is prevented.

The heliostat reflector 10 with the reflector mounting structure 30 in FIG. 1 can be manufactured, for example, by the following manufacturing process.

<< Process 1 >>
An ordinary silver mirror having the structure of the reflecting mirror 18 with the protective layer of FIG. 1 is prepared. In the normal silver mirror 18, the transparent substrate 12 is formed of a transparent glass substrate. A protective glass plate is prepared as a protective plate 22 that covers the entire back surface of the silver mirror 18.

<< Process 2 >>
An adhesive 20 is applied to the entire back surface of the silver mirror 18 to bond the protective glass plate 22.

<< Process 3 >>
Each layer 14, 26 sandwiched between the transparent glass substrate 12 and the protective glass plate 22 is formed by applying and curing an epoxy-based sealing material 24 on the entire periphery of the outer edge surface 23 of the laminated structure formed through the step 2. , 28 and 20 are sealed with a sealing material 24 to be shielded from the outside air. Instead of applying the sealing material 24 separately to the outer edge surface 23 of the laminated structure and sealing the outer edge surface 23, the protective glass plate 22 is protected when the adhesive glass 20 is adhered to the back surface of the silver mirror 18. The outer edge surface 23 can also be sealed by curing the adhesive 20 flowing out (extruding) from between the glass plate 22 and the silver mirror 18 to the outer edge surface 23 as it is or as needed.

<< Process 4 >>
A reflector mounting structure 30 made of metal or the like of heliostat is bonded with an adhesive 32 to the central portion of the surface of the protective plate 22 on the back surface of the reflector 10 for heliostat completed through the step 3.

  2 and 3 show the overall configuration of the heliostat 34 on which the heliostat reflector 10 with the reflector mounting structure 30 of FIG. 1 is mounted. FIG. 2 shows the back and FIG. 3 shows the side. This heliostat 34 uses a pedestal platform. The heliostat 34 includes, as a reflector support mechanism 42, a foundation 38 installed on the ground 36 and a support column 40 installed vertically on the foundation 38. The reflecting mirror mounting structure 30 is supported on the upper end of the support column 40 so as to be rotatable in a three-dimensional direction, that is, an azimuth angle direction (a direction around the vertical axis) A and an elevation angle direction (a direction around the horizontal axis) B. . The reflector mounting structure 30 is obtained by the azimuth direction A and the elevation angle by an azimuth direction electric drive device and an elevation direction electric drive device (both not shown) disposed between the reflector mounting structure 30 and the column 40. It is driven to rotate independently in direction B. As a result, the heliostat reflecting mirror 10 that is integrally supported by the reflecting mirror mounting structure 30 reflects the sunlight and rotates in the azimuth direction A and the elevation direction B following the movement of the sun to reflect. Sent sunlight to a predetermined target position.

A weather resistance experiment performed on the heliostat reflector 10 of FIG. 1 and other reflectors will be described.

《Experimental conditions》
(1) Prepared reflectors:
The following samples were prepared as reflecting mirrors. Here, each sample used a normal silver mirror in which a silver layer was formed on the same type of transparent glass substrate by a silver drawing method, and a protective layer was formed on the silver layer. The protective layer is composed of a copper layer and a paint layer, and the paint layer is made of a coating containing an oxidation polymerization type alkyd resin, titanium oxide, ferric hydroxide (yellow iron oxide), and cobalt naphthenate. It was applied on top and dried.

-Sample 1a: Silver layer + protective layer-Sample 1b: Same structure as sample 1a-Sample 2a: Silver layer + protective layer + fluorine coating layer (fluorine paint on the entire protective layer and laminated structure
(Applied to the entire periphery of the outer edge surface and dried to seal the protective layer and the outer edge surface)
Sample 2b: Same structure as sample 2a Sample 3a: Silver layer + protective layer + epoxy resin layer (epoxy resin over and over the protective layer)
Apply to the entire outer edge of the structure and dry to seal the protective layer and outer edge)
・ Sample 3b: Same structure as sample 3a ・ Sample 4a: Silver layer + protective layer + protective glass plate (protective glass plate is completely protected with epoxy adhesive
Adhere to the surface and seal the entire protective layer. At this time, between the protective layer and the protective glass plate
Dry the epoxy adhesive that flows to the outer edge of the laminated structure to seal the outer edge.
Stop. Heliostat reflector according to the present invention)
Sample 4b: Same structure as sample 4a

(2) Experimental method:
Each sample is put into a high-temperature and high-humidity tester, the atmosphere inside the high-temperature and high-humidity tester is maintained at 85 degrees Celsius, and the humidity is 95%. The change in rate was measured by the direct measurement method defined in DJIS 5705. Since all the samples could not be put into the high-temperature and high-humidity tester at the same time due to the capacity limitation of the high-temperature and high-humidity tester, the experiment was conducted for each group in the following groups.
Group 1: Sample 1 (a, b, c, d)
Group 2: Sample 2 (a, b), 3 (a, b)
Group 3: Sample 4 (a, b)

"Experimental result"
FIG. 4 shows the temporal change characteristic of the reflectance of each sample obtained by the experiment.

《Experimental considerations》
According to FIG.
Sample 1 (a, b): The reflectance decreases rapidly with time.
Sample 2 (a, b): Similar to Sample 1, the reflectance decreases rapidly with time.
Sample 3 (a, b): The rate of change in reflectance is slower than that of samples 1 and 2, but the reflectance decreases with time.
Sample 4 (a, b) (reflector for heliostats according to the present invention): No decrease in reflectivity is observed compared to the start of the experiment. Therefore, the heliostat reflecting mirror 10 in which the protective glass plate 22 is bonded to the back surface of the normal silver mirror 18 is sufficient as the heliostat reflecting mirror because the protective glass plate 22 blocks the silver layer 14 and the protective layer 16 from the outside air. Durability (weather resistance) is obtained.

  In the above-described embodiment, the adhesive 20 is applied to the entire surface of the protective layer 16 and the protective glass plate 22 is adhered. However, the adhesive 20 is not limited to this and is applied only to the entire periphery of the peripheral edge of the protective layer 16. The protective glass plate 22 can also be adhered. In the above embodiment, the protective plate is made of a glass plate. However, the protective plate is not limited to this, and the protective plate is a plate made of another inorganic material such as a non-breathable and non-permeable ceramic plate, a metal plate, or a ceramic coated metal plate. Or it can also be comprised with the resin board which has air permeability and water-impermeable property, such as PMMA. Moreover, although the transparent substrate was comprised with the transparent glass substrate in the said embodiment, not only this but a transparent substrate can also be comprised with transparent resin plates, such as PMMA. Moreover, although the reflective layer was comprised with silver in the said embodiment, not only this but a reflective layer can also be comprised with metal materials, such as aluminum and chromium. In the above-described embodiment, the heliostat reflecting mirror is configured as a plane mirror. However, the heliostat reflecting mirror is not limited thereto, and the heliostat reflecting mirror may be configured as a reflecting mirror having a curvature. In this case, the transparent substrate and the protective plate can be constituted by plates having the same curvature. Further, in the above-described embodiment, one reflector 18 with a protective layer and one protective plate 22 are bonded, but instead of this, a plurality of small pieces of protection are provided on the front surface of one protective plate. The heliostat reflector of the present invention can also be configured by arranging the layered reflectors side by side.

  DESCRIPTION OF SYMBOLS 10 ... Reflector for heliostats, 12 ... Transparent substrate (transparent glass substrate), 14 ... Reflective layer (silver layer), 16 ... Protective layer, 18 ... Reflector with protective layer (silver mirror), 20 ... Adhesive, 22 ... Protective plate (glass plate), 26 ... copper layer, 28 ... paint layer, 30 ... reflector mounting structure, 34 ... heliostat, 42 ... reflector support mechanism

Claims (8)

A reflective mirror with a protective layer in which a reflective layer is formed on the back surface of the transparent substrate and a protective layer is formed on the reflective layer;
A heliostat reflector comprising: a non-breathable and non-breathable protective plate adhered to the back surface of the reflector with a protective layer with an adhesive.   The heliostat reflector according to claim 1, wherein the protective plate covers substantially the entire surface of the protective layer.   The heliostat reflector according to claim 1 or 2, wherein the protective plate is bonded to the protective layer over substantially the entire surface facing the protective layer.   The heliostat reflector according to any one of claims 1 to 3, wherein the reflective layer has a silver layer, and the protective layer has a copper layer and a coating layer formed on the copper layer.   The heliostat reflector according to any one of claims 1 to 4, wherein the protective plate includes at least one of a glass plate, a ceramic plate, a metal plate, a ceramic-coated metal plate, and a resin plate. Heliostat reflector according to any one of claims 1 to 5;
A reflector mounting structure bonded to the back surface of the heliostat reflector with an adhesive;
A heliostat comprising: a reflector support mechanism that supports the reflector attachment structure so as to be able to displace following the movement of the sun. Preparing a reflective mirror with a protective layer in which a reflective layer and a protective layer are sequentially formed on the back surface of the transparent substrate;
A method of manufacturing a reflector for heliostats, comprising: adhering a non-breathable and non-water-permeable protective plate on the protective layer of the reflective mirror with a protective layer with an adhesive.   The manufacturing method of the reflector for heliostats of Claim 7 which performs the said adhesion | attachment in a non-vacuum atmosphere.

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