DE102009047945A1 - Method for producing a shaped mirror, shaped mirror and parabolic trough for solar collectors - Google Patents

Abstract

The method according to the invention relates to the production of a shaped mirror (F) which has a surface (2) which is curved in a predetermined manner. The method comprises the steps of: forming a shaped body (1) in which at least a part of its surface reproduces the predetermined curved surface, applying a glass layer (3) over the entire surface and without gaps to the predetermined curved surface of the shaped body, wherein the glass layer has a surface opposite the bearing surface to the molded body, on which a mirror coating (4) is arranged, and application of a carrier layer (5) to the mirror coating, the carrier layer being connected to the mirror coating and, after separating the shaped mirror from the molded body, the maintains predetermined curvature. The method also relates to the use of a mirrored metal layer instead of the glass layer for reflection. The invention also relates to a shaped mirror produced by means of the method, as well as a parabolic trough for a solar thermal power plant which uses the shaped mirror.

Description

The present invention relates to a method for producing a shaping mirror, in particular for bundling irradiated sunlight, a shaped mirror produced by the method, and a parabolic trough which uses the shaping mirror.

Mirrors and mirror elements, which have a predetermined three-dimensional shape and in particular are designed as a concave mirror, are used in many areas for reflection and guidance of visible and invisible light. One application is, for example, the formation of concave mirrors or mirror elements, by means of which sunlight is reflected and concentrated at predetermined locations. More specifically, this application relates to the formation of parabolic mirrors which are assembled into so-called parabolic troughs. In this case, according to a parabolic shape, curved mirrors or mirror elements are arranged on a correspondingly designed carrier device such that the parabolic trough is formed and the concentrated sunlight reflected by the parabolic trough is focused on a focal line of the parabolic trough on an absorber tube which runs along the focal line.

Such an arrangement serves as an energy source of a solar thermal power plant, wherein the parabolic mirrors or mirror elements of the parabolic trough serve as a reflector for the incident sunlight. The absorber tube is flowed through by a heat transfer fluid, wherein in the course of flow of the heat transfer fluid through the absorber tubes of the entire parabolic trough the heat transfer fluid is heated so that directly or via a heat exchanger steam can be generated, by means of which a turbine is driven, which in turn one with the Turbine connected generator can provide power to provide electrical power.

The parabolic mirrors and the associated absorber tube arranged in the focal line form a solar collector, and a plurality of solar collectors forms the parabolic trough, wherein a plurality of parabolic trough rows are arranged for the solar thermal power plant depending on the expected and intended performance.

The parabolic troughs and in particular the parabolic mirrors or mirror elements are precise optical devices which have to be aligned less than a millimeter in order that the incident sunlight can be bundled as well as possible in the absorber tube for heating the heat transfer fluid. In order to obtain the efficiency of a parabolic mirror or a parabolic trough at a high value, it is necessary on the one hand to align the parabolic troughs very closely to the sun and track according to the changing position of the sun, and on the other hand to observe the exact parabolic shape (curvature) of the parabolic mirrors or mirror elements.

In general, parabolic curved individual mirrors (mirror parts, mirror elements) are assembled into a larger parabolic mirror (parabolic mirror). The individual curved mirror elements are arranged on a steel girder construction as a carrier and fastening device.

The production of bent glass as a basis for the production of parabolic mirrors or parabolic curved mirror elements is very expensive and requires large amounts of energy, since in general by means of a gas burner, the glass must be heated to about 600 C. The facilities required for this have a large footprint and also cause significant costs.

A bending operation for producing the bent glass essentially involves heating, bending the glass and cooling, which requires a longer time of production, which may be more than 16 hours.

Furthermore, the glass required is very heavy and therefore cumbersome in manufacturing, handling and assembly. A mirror having a thickness of, for example, about 4 mm and an area of about 2 m ² comprises a mass of 25 kg, including the corresponding fasteners, for placing the mirror on a suspension device.

It is also necessary in the production, the so-called ripple (kielne unevenness in the glass surface or small differences in the thickness of the glass) to keep very low, otherwise the reflection of the incident sunlight on the absorber tube at the expense of the overall efficiency of the solar panels and thus of the solar thermal power plant is deteriorated. In particular, the handling of such a glass in the manufacture and assembly on site in a solar thermal power plant formed a potential hazard to the staff by fragmentation in the event of glass breakage.

With regard to the mirroring of the glass, it is necessary to carry out the further measures for applying the silvering to one of the sides of the glass under clean-room conditions. The treatment takes place in several steps with special chemical substances, which are partly poisonous and expensive, whereby during the production accumulating waste and wastewater are generally very expensive to dispose of.

The production of a curved glass mirror is therefore complicated and requires a qualified staff, so on the one hand high labor costs incurred and on the other hand in the entire production process, the possibility of producing rejects is relatively large.

Furthermore, as a result of the high weight of the curved glass mirror up to the site of shipping and transport and installation at the site very expensive and expensive.

On the other hand, the object of the present invention is to provide a method for producing a shaped mirror having a predetermined curvature such that both the production of the shaped mirror and the handling of the finished shaped mirror are considerably simplified.

According to the invention, this object is achieved by a method for producing a shaped mirror having the features specified in claim 1, with a shaped mirror having the features specified in claim 13, as well as with a parabolic trough having the shaping mirror.

According to a first aspect, the method according to the invention relates to the production of a shaping mirror which has a predetermined curved surface. The method comprises the steps of forming a shaped article in which at least part of its surface reflects the predetermined curved surface, applying in full-surface and gap-free manner a glass layer to the predetermined curved surface of the molded article, the glass layer having a surface opposite to the surface Support surface to the molded body, on which a mirror coating is arranged, and applying a carrier layer on the mirror coating, wherein the carrier layer is connected to the mirror coating and after separating the mold mirror of the molded body maintains the predetermined curvature.

By means of the abovementioned process according to the invention, the production of a shaping mirror is considerably simplified. The moldings serving as the basis molding is formed in a precise manner, and thus it takes the approximately full-surface and gap-free applied to the molding glass, which is formed substantially as a thin glass layer, the shape and thus the predetermined curvature of the molding , By using the glass layer produced as a flat thin layer, the residual ripple of the glass is considerably reduced and reduced to almost zero in comparison with the bent glass produced with the complex production process. Thus, the efficiency of a solar collector equipped with the inventive mirrors of a solar thermal power plant can be increased, at the same time a uniform heating of the heat transfer fluid is ensured in the absorber tube in the focal line of the solar trough. In the case of using a thermal oil as a heat transfer fluid local heating in the absorber tube and thus the risk of deterioration of the thermal oil is avoided.

With the use of the thin glass layer, the reflection of the mirror can be improved, and reduce manufacturing costs, in particular by eliminating a warm bending process. The shaping of the shaped mirror by means of the shaped body, to which the thin glass layer including the mirroring and then the support layer are applied, also allows simplified operations in the production of the mold level or parts thereof (molded mirror parts), so that no great demands are placed on a specialist and at the same time the risk of producing waste is reduced.

The shaping mirror comprises the carrier layer permanently ensuring the predetermined curvature. Compared to known designs of a curved mirror depending on the size of the mold mirror or parts of the mold mirror results in a significant reduction in weight, in some cases the weight achieved in connection with the inventive method is less than half the weight of known designs of curved mirrors.

The lower weight also leads to a facilitated and therefore cost-effective transport of the mold mirror or molded mirror parts, and also facilitates the assembly of the parts at the installation of the mold mirror, for example, at the site of a solar thermal power plant. The reduced weight thus also allows the consideration of sites of solar thermal power plants with the inventive mirrors on buildings without significant measures to secure and reinforce the building are required.

In the subclaims advantageous embodiments of the present invention are given, which relate to various aspects of the invention.

According to the method, the carrier layer may consist of a plastic material, and in particular of a GfK composite material consists. As a result, a strength is achieved with low weight.

The thickness of the glass layer may be in a range of 2 mm to 3 mm, so that the path of irradiated light through the glass layer is small.

Furthermore, in the method, the step of applying a carrier layer comprises the step of applying the carrier layer in a plurality of individual layers. In this case, at least one of the individual layers of the carrier layer can not completely cover the surface of the glass layer curved in a predetermined manner. In this way, material can be saved while stability.

In the case of the shaping mirror, the surface of the shaped body which is curved in a predetermined manner at least partially follows the course of a parabola, so that a parabolic mirror is formed which is suitable for a solar thermal power plant.

The shaped body for carrying out the method may be designed such that the surface of the shaped body curved in a predetermined manner reproduces at least part of the shape of a parabolic trough. The mold mirror can be formed in this way in parts, whereby the handling is facilitated.

Furthermore, the individual layers of the carrier layer can be applied to the silvering by lamination. At least one of the individual layers of the carrier layer applied directly to the silvering can be applied over the whole surface and the surface of the glass layer can be completely covered, and at least one of the further individual layers of the carrier layer can not completely cover the surface of the previously applied single layer of the carrier layer, thus saving material and a Reduction of weight can be achieved.

In the method, the step of applying the carrier layer to the mirror coating may include incorporating fasteners into the carrier layer so that the forming mirror can be easily attached to carrier devices in conjunction with the carrier layer.

According to a second aspect of the present invention, the method of manufacturing a mold mirror having a predetermined curved surface comprises the steps of: forming a molded article having at least two frame members, the shape of the frame elements reflecting the predetermined curved surface of the molding game pattern; Applying a metal layer to the shaped body, wherein the metal layer has a surface adjacent to the shaped body, on which a mirror coating is arranged, and applying at least two carrier elements to the metal layer, wherein the carrier elements are connected to the metal layer and after separating the mold mirror from the shaped body maintain the predetermined curvature. Here, the thickness of the metal layer may be in a range of 1 mm to 3 mm.

With the use of a metal layer for the formation of the reflection surface, a further weight reduction and in particular a reduction of the production costs can be achieved. It also simplifies the steps required to make the mold mirror, so that high-quality manufacturing is ensured even with simple tools and on average trained personnel.

The present invention further includes a mold mirror having a metal layer which has a predetermined curved shape and wherein one of the surfaces of the metal layer has a mirror finish, at least two support members applied to and fixed to the other surface of the metal layer the shaping mirror can be produced by means of the method described above according to the second aspect of the invention.

The present invention also includes a mold mirror having a glass layer which has a curved shape in a predetermined manner and wherein one of the surfaces of the glass layer has a mirror finish and a support layer applied to and fixed to the mirror surface. In this case, the shaping mirror can be produced by means of the abovementioned method according to the invention in accordance with the first aspect. According to a use of the shaping mirror, a parabolic trough according to the invention for solar collectors of a solar thermal power plant can have at least one of the above-described shaping mirrors.

The invention will be described below with reference to embodiments with reference to the figures. Show it:

1 a simplified schematic representation of a shaped body according to a first embodiment of the present invention,

2 a schematic representation of the application of a glass layer on the molding according to 1 .

3 a schematic representation of the molding according to 1 in which the entire surface of the glass layer is applied,

4 a schematic representation of the molding according to 1 including the full-surface glass layer, wherein a carrier layer is applied to the glass layer,

5 a schematic representation of the molding according to 1 and with the glass layer and the complete carrier layer according to 4 .

6 a schematic representation of the shaped body including the glass layer according to 3 wherein the carrier layer is applied in multiple layers,

7 a schematic representation of two molded mirror parts, which are composed to form an entire shape mirror,

8th a schematic representation of the molding according to 1 and the glass layer and the carrier layer, on which support elements are arranged,

9 a schematic representation of molded mirror parts with support elements according to 8th .

10 a schematic representation of a solar collector in the form of a parabolic trough, which is formed from mirror elements,

11 a simplified schematic representation of a shaped body according to a second embodiment of the present invention, and

12 a schematic representation of a shaped game gel according to the second embodiment.

First embodiment

Hereinafter, the method of manufacturing a mold mirror according to a first embodiment of the present invention will be described with reference to FIGS 1 to 5 described.

1 shows in a simplified perspective view of the arrangement of a shaped body 1 which serves as the basis for the production of the mold mirror. The molded body 1 is formed such that at least one side of the shaped body 1 a curved surface 2 having a predetermined curvature. The predetermined curved surface 2 has a curvature which is the negative shape of the desired curvature of the mold level F to be produced (see, for example, US Pat 7 . 9 and 10 ) having. For the application of the shape mirror F to form a parabolic trough, for example, a solar thermal power plant follows the curvature of the desired parabolic shape. The predetermined curvature is thus that of a parabola. However, the invention is not limited to the formation of a parabolic shape. Rather, any shapes can be formed.

On the molding 1 with the predetermined curved surface 2 is shown in 2 applied a first layer. The first layer consists of a glass layer 3 which are so on the curved surface 2 of the molding 1 is applied, that it rests there approximately over the entire surface and gap-free and thus the curved in a predetermined manner surface 2 exactly follows. The glass layer 3 , which is preferably made of thin glass, is placed on the curved surface 2 applied, in which the glass layer is cold (at room temperature) corresponding to the curved surface 2 is bent. In the method according to the invention for producing the shaping mirror F, it is not necessary in this bending process to use the preferably thin and largely flat glass layer in the original state 3 to heat to adjust the glass layer 3 to the shape of the molding 1 ,

On the molding 1 During manufacture, it rests directly on the molding 3 Glass layer held by, for example, holding elements 1a be used. The holding elements 1a attach and hold preferably the glass layer 3 at the edge areas of the same, so that the glass layer 3 takes the desired predetermined shape. There is also the option of the glass layer 3 by means of a negative pressure on the molding 1 to fix. For this purpose, at different points on the curved in a predetermined manner surface of the molding 1 openings 1b arranged, which are connected to a negative pressure generating means (not shown) and wherein the glass layer 3 on the molding 1 is sucked in and thus the glass layer 3 abuts the entire surface and the predetermined shape of the molding follows, which is maintained during further processing.

The thickness (thickness) of the glass layer is in a range of about 2 mm to 3 mm, and is preferably 2.2 mm to 2.5 mm. With this glass thickness, the path that generally light rays and in particular sun rays must travel through the material of the glass when using the mold mirror F, for example, in a solar thermal power plant decreases from about 8 mm or more in known versions of curved mirrors to about 4 , 4 mm to 5 mm. The efficiency of the entire mirror assembly can be increased.

On one side (surface) of the thin glass layer 3 that are not attached to the molding 1 is applied, ie on a first surface 31 across from the support surface (a second surface 32 ) of the glass layer 3 to the molded body 1 , is a mirroring 4 applied. For this purpose, the first surface 31 for receiving the mirroring 4 prepared in a similar manner, ie substantially cleaned and polished, and the mirroring 4 Essentially consists of a thin metallization layer on the first surface 31 the glass layer 3 is applied and on its back (the then exposed surface of the mirror coating 4 ) receives a protective finish.

In the present case, the preparation of the glass layer 3 at its first surface 31 and mirroring at the time of manufacture of the glass layer 3 be made, or it may be the preparation of the glass layer 3 and the mirroring, ie the application of the mirroring 4 on the first surface 31 the glass layer 3 also be made when the glass layer 3 already on the molding 1 arranged and attached. In general, the application of the mirror coating 4 with special processes under a protective atmosphere in the form of a very thin layer.

As it is in 4 shown is on the glass layer 3 on the side of the mirroring 4 ie on the mirroring 4 a carrier layer 5 applied, wherein the carrier layer 5 firmly with the glass layer 3 or the mirroring 4 connected is. The carrier layer 5 may for example consist of a plastic composite material. In particular, a GfK composite material (plastic matrix with glass fibers) may be provided. In particular, glass fiber mats can be applied (laminated) in conjunction with a two-component resin. As it is according to 4 is recognizable, follows the shape of the entire surface on the glass layer 3 and the mirroring 4 applied carrier layer 5 completely the predetermined curvature, and thus in the case of the application of the mold mirror F in a solar thermal power plant, the curvature of a parabola.

The full surface with the glass layer 3 and the mirroring 4 connected carrier layer 5 retains the predetermined curvature after curing and thus serves to support and support the glass layer attached thereto 3 with the mirroring 4 as a mirror element, so that the predetermined curvature of the formed shape mirror F is maintained during the life of the mold mirror F.

With the inherent stability of the carrier layer 5 the predetermined curvature and thus for example the parabolic shape are maintained.

The formation of the carrier layer 5 is not limited to the plastic composite material, but may also be formed, for example, from an epoxy foam. In this case, it is necessary that the layer thickness of the epoxy foam assumes a predetermined size, so that the required inherent stability of the carrier layer 5 is guaranteed and over a longer period of operation, for example, a solar trough for a solar thermal power plant, the parabolic shape and thus the support property for the mirrored glass layer 3 can be maintained.

In the 4 and 5 is the carrier layer 5 in the form of a layer (single layer, single layer), and it is the carrier layer 5 full surface with the glass layer 3 on the side of the mirroring 4 connected.

In a further embodiment, as shown in FIG 6 the carrier layer 5 consist of different individual layers, these different individual layers successively on the glass layer 3 or on the previous single layer of the carrier layer 5 can be applied.

Is the glass layer 3 including the mirroring 4 on the molding 1 with the predetermined shape or curvature 2 arranged and fixed and thus has the glass layer 3 assumed over the entire surface and gap-free, the predetermined curvature, then a first single layer 51 the carrier layer 5 directly on the mirroring 4 the glass layer 3 be applied. This covers the first single layer 51 the carrier layer 5 completely the surface of the glass layer 3 and the mirroring 4 , The first single position 51 thus already causes a carrier property for the glass layer 3 including the mirroring 4 and also protects the mirroring 4 from her back.

On the first single position 51 can be a second single layer 52 be applied, the second single layer 52 the same area and thus the total area of the glass layer 3 can cover, this being the total area of the first single layer 51 equivalent. Alternatively, the second single layer 52 take up only a part of the total area, that of the first single layer 51 is covered, wherein in the illustration according to 6 indicated is that the second single layer 52 in front of the right edge of the first single layer 51 ends. In the same way, a further single layer, such as a third single layer 53 the carrier layer 5 , the total area of the previous single location 52 or also a smaller area compared to that by the second single layer 52 Cover covered area. The third single position 53 preferably covers only a part of the second single layer 52 covered area. Thus, at least one of the individual layers of the carrier layer 5 not the entire surface of the glass layer ( 3 ) cover.

In 6 is a fourth single layer 54 shown, wherein the number of individual layers on the thickness (thickness) of the individual individual layers and thus on the stability of the entire arrangement of the mold mirror F or the relevant part of the mold mirror F depends. The in 6 shown part of the mold mirror is assembled with a similar further part of the mold mirror F to an entire mold mirror F, so that at the outer ends of the respective parts of the mold mirror F, the corresponding further individual layers not the entire surface of the glass layer 3 cover.

For applying the various other individual layers, such as the second to fourth single layer 52 to 54 the carrier layer 5 the glass layer preferably remains 3 including the mirroring 4 and some of the individual layers of the carrier layer 5 on the molding 1 so as to ensure that the formed mirror F or the formed parts of the mirror F exactly match the predetermined curvature 2 take over and comply with the molding. Is the strength of the carrier layer achieved with a single layer or a plurality of individual layers 5 sufficient to ensure the required stability of the mold mirror F, then the mold mirror F of the molded body 1 be solved.

7 shows in a simplified and schematic manner, the arrangement of two (preferably symmetrical) parts of the mold mirror F, which together, for example, give a parabolic trough on each of its sides. The two parts of the forming mirror F are in the range of a holder direction 6 with each other and with the holder device 6 connected. The attachment to the holder device 6 and the parts of the mold mirror F ensures each other that also comply with the items in their entire arrangement the desired curvature and thus, for example, the arrangement according to the course of a parabola.

In the in 7 example shown, each part of the mold mirror F, for example, the individual layers 51 . 52 and 53 the carrier layer 5 on. While the first single position 51 in the same way as it is in 6 is shown, the entire surface of the glass layer 3 and the mirroring 4 covering, are the second and third single layer 52 and 53 the respective parts of the mold mirror F applied on their outer sides such that not the entire surface of the glass layer 3 is covered. In this way, the formation of a respective single layer of the carrier layer 5 be made such that on the one hand, a saving of material is possible, and on the other hand, the mechanical stability of the entire mold mirror F and compliance with the predetermined curvature (for example, a curvature corresponding to a parabola) is ensured.

The in 7 Shaped mirror shown may preferably at a rotational axis 7 in the area of the holder device 6 be rotated or pivoted to allow tracking in accordance with the changing position of the sun.

Furthermore, in 7 above the forming mirror F an absorber tube 8th shown that flows through a fluid heat transfer medium, such as a thermal oil or a correspondingly treated water. The absorber tube 8th is arranged at the dividing line of the parabolic trough, consisting of the shaping mirror F, and the sun rays reflected by the shaping mirror F in a predetermined manner become in the focal line and thus on the absorber tube 8th bundled, so that in the absorber tube 8th flowing heat transfer medium is heated. When using the mold mirror F in a parabolic trough of a solar thermal power plant thus the collectors from the mold mirrors F in conjunction with solar radiation is the primary heat source. The heat transfer to a steam generator by means of the fluid heat transfer medium in the absorber tubes (for example, the absorber tube 8th ) flows.

In the figures described above, the carrier layer is 5 indicated as a (also consisting of several individual layers) layer, on the one hand, the relatively thin glass layer 3 with the mirroring 4 protects, and on the other hand ensures that the desired shape (the predetermined curvature) of the mold mirror F is also observed long term. This ensures a consistently high efficiency of the solar collectors or parabolic trough of the solar thermal power plant, or in other applications consistent predetermined mirror properties.

8th shows in the same way as 5 the arrangement of the molding 1 on which the thin glass layer 3 including their mirroring 4 is applied. On the glass layer 3 and in particular the mirror coating arranged thereon 4 is the carrier layer 5 formed, wherein in the illustration of 8th to simplify the carrier layer 5 is formed as a single layer.

In the formation of the carrier layer 5 was taken into account that the shape of the mirror F or the part of the mirror F, which is on the molding 1 is generated, depending on the situation of installation at the site requires more support elements. 8th shows such a support element 9 , which is designed as a substantially flat metal structure, preferably made of steel or light metal. In the presentation of the 8th lies the substantially planar support element 9 in the paper plane. To reduce the weight of the carrier element 9 has the carrier element 9 at predetermined Make recesses, taking the stability of the support element 9 is guaranteed.

In the application of the carrier layer 5 on the glass layer 3 are preferably in the carrier layer 5 fasteners 10 installed so that by means of these fasteners 10 which are provided in a predetermined required number, the support member 9 with the shaping mirror F and in particular the carrier layer 5 can be connected stable and detachable. In the case of application of the support elements 9 in conjunction with those on the carrier layer 5 arranged fasteners 10 an overall stability of the mold level F or a part of the mold level F is ensured, since both the carrier layer 5 as well as the respective carrier elements 9 contribute to the stability of the entire shape mirror F.

The schematic representation in 9 shows in a similar way as in 7 the formation of an entire shape mirror F of two preferably symmetrical parts of the forming mirror F, which in conjunction with the holder device 6 connected to each other.

The two interconnected parts of the mold mirror F are essentially parts as they are in 8th are shown, wherein on the carrier layer 5 by means of the fastening elements 10 the carrier elements 9 are arranged. In the present case, ie in the case of the shaped mirror F according to FIG 9 For example, two individual layers in the form of a first single layer 51 and a second single layer 52 the carrier layer 5 provided, and in the second single position 52 are the fasteners 10 installed, where the support elements 9 can be arranged. It is not necessary that the support elements 9 each follow the entire arc shape of the mold mirror F, since the stability of the entire arrangement, ie the mold mirror F or the parts of the mold mirror F by the connection of the support elements 9 with the carrier layer 5 is sufficiently ensured. Indicates the carrier layer 5 several individual layers, then the fasteners 10 arranged in at least one of the individual layers.

In the same way as in the representation of 7 the entire shaping mirror F is rotatable in connection with the axis of rotation 7 , or pivoting, so that a tracking to the changing position of the sun is guaranteed. Likewise is in 9 the absorber tube 8th indicated in the present case in the application of the mold level in a parabolic trough of a solar thermal power plant flows through the fluid heat transfer medium.

The entire arrangement of the shaping mirror F or the parabolic trough formed from at least two shaped mirror parts 9 ensures compliance with the predetermined curvature, and in particular the curvature with the course of a parabola, so that even with a longer operating time and thus a longer residence time of the arrangement outdoors the predetermined curvature of the mirror surface (the glass layer 3 in conjunction with the mirroring 4 ) is safely maintained. Deterioration of the efficiency of the entire parabolic trough by a curvature that changes during the life of the assembly is thus avoided. Furthermore, the above-described arrangement of the entire mold level F or the parts of the mold level F for corresponding personnel is easy to handle, especially with regard to shipping and installation of the parts of the mold mirror F. This is the illustration in 10 referenced, in which a parabolic trough is indicated in a simplified and schematic representation, which consists of two parts of the mold mirror F, as for example in the 7 and 9 are arranged.

If a length L of the parts of the forming mirror F and a width B is selected in a predetermined manner, then it is possible to ship the parts of the forming mirror F in a simple way in a shipping container with standard dimensions. In this case, the length may be, for example, 15 m and the width B of a mirror part 3 m. Compared with the weight (mass) of known arrangements with curved mirrors, which is partly about 5000 kg, with the shaping mirror F according to the present invention a mass of about 1500 kg to 2500 kg is achieved. This greatly simplifies handling during shipping as well as assembly, whereby simpler equipment such as hoists can be used.

In the schematic representation of the parabolic trough in 10 it can be seen from two parts of the shaped mirror F that the entire arrangement by means of the carrier elements 9 and the holder device 6 can be attached to the location of the application, provided that it is ensured that the parabolic trough of the solar movement can be tracked throughout the day.

Is an arrangement of the mold mirror F or the parts of the mold mirror F as shown in FIG 7 before, in which the carrier elements 9 as they are in 9 are shown are not provided, then are in the carrier layer 5 and in particular in, for example, the outer carrier layer (third carrier layer 53 in 7 ) corresponding fastening elements provided by means of which the parts of the mold mirror F can be assembled and fixed to form the parabolic trough.

The arrangement of the mold mirror F according to the present invention and the above description thus connects the thin glass layer 3 on which a mirror coating 4 is applied, with the (for example, multi-layer) running carrier layer 5 , wherein the carrier layer 5 the glass layer 3 and the mirroring 4 protects and holds in the form, ie with the predetermined curvature, by the predetermined curvature 2 of the molding 1 is predetermined. Any number of shapes can be used here. The above description shows as an example the application in a parabolic trough for a solar thermal power plant, wherein the predetermined curvature 2 of the shaped body of a parabola follows. Furthermore, the shaping mirror F may be formed as a single piece and thus the single solar collector of the parabolic trough may be formed in one piece, or the shaped mirror F may consist of a plurality of parts of the shaping mirror F to form a predetermined mirror surface, such as a parabolic trough , This arrangement is in 10 shown using the parabolic trough as an example.

It has the mirror glass of the glass layer 3 with the mirroring 4 and the carrier layer 5 essentially the same coefficient of expansion, so that with temperature differences only low stresses at the transition between the curved surface of the glass layer 3 and the carrier layer 5 arise. The glass layer 3 with the mirroring 4 is fixed to the carrier layer 5 (and in the case of the multilayer backing layer 5 with the first carrier layer 51 ) and fully connected.

The low thickness of the glass layer 3 has the advantage that before the application of the glass layer 3 on the molding 1 for determining the predetermined curvature 2 the glass layer 3 does not have to be pre-bent. The bending process can be cold in connection with the simple application of the glass layer 3 on the molding 1 respectively.

The carrier layer 5 , even in its multilayer design according to, for example, the 6 and 7 , may have UV protection. In particular, the plastic composite material, for example of GfK composite material (glass fiber reinforced plastic) or an epoxy foam may have a UV protection. By using the UV protection, the material properties can be retained longer, so that the service life of the carrier layer 5 can be extended. The overall arrangement has a high strength with low material cost and a high long-term stability.

The entire assembly has sufficient flexibility, and is characterized by a low vibration. Furthermore, a secure transport of the mold mirror F or parts of the mold mirror F is guaranteed because the glass layer 3 firmly with the carrier layer 5 is connected and thus there is little probability that the glass layer 3 can be damaged.

The low weight and thereby facilitated handling of the mold level or parts also allow the reduction of freight costs.

With the elimination of the separate bending process for the glass layer 3 and the simplified and secure bending of the glass layer 3 when cold, the cost of production is significantly reduced, also with regard to the possibility of using an average qualified staff and the use of simpler facilities. In particular, the production of the mold level F according to the method described above can be carried out under normal air conditions, so that no special clean room conditions are required. In the case of the application of a glass fiber fabric for the formation of the carrier layer 5 required plastic materials such as resin and hardener require no special storage conditions and there are no polluted wastewater in the production. The simplified production process also produces very little rejects, even if the manufacturing process is performed by a simple staff.

At the location of the formation of the mold level F, for example in the form of a parabolic trough, only a light device is needed to mount the entire assembly on site. At the same time a simple assembly is ensured in particular by the significantly lower weight. Also due to the low weight are smaller or weaker foundations required, and it is necessary for the tracking of the mirror to the changing day in the sun's position, only a small amount of energy, and smaller and thus cheaper drives can be used.

The entire structure of the mold mirror F required in conjunction with the carrier layer formed from a plastic composite material 5 no further preservation.

It further simplifies the production of the mold mirror, as the curved in a predetermined manner surface 2 of the molding 1 is such that after fixing the glass layer 3 and the application of the carrier layer 5 the entire arrangement of the mold mirror F slightly from the molding 1 can be separated. After curing of the carrier layer 5 is the shape mirror F in terms of shaping and its Handling stable and can be further processed easily.

Second embodiment

Hereinafter, the method of manufacturing a mold mirror according to a second embodiment of the present invention will be described with reference to FIGS 11 and 12 described.

11 shows in a simplified perspective view of the arrangement of a shaped body 40 according to the second embodiment, which is the basis for the production of the shaping mirror f (see 12 ) serves. In contrast to the molded body 1 according to the first embodiment, the molded body 40 is formed such that it does not have a smooth and predetermined curved surface ( 2 in 1 ) having. Rather, there is the molding 40 from at least two frame elements 41 Standing on a corresponding substructure unit 43 are arranged. The substructure unit 43 includes several sub-components 44 leading to a stable and the at least two frame members 41 supporting frame are composed. On the substructure unit 43 are preferably the perpendicular at least two frame elements 41 arranged parallel to each other. On her the substructure unit 43 opposite edges have the frame elements 41 a corresponding profile or the predetermined curvature.

The predetermined curved edges of the frame elements 41 have a curvature that the negative shape of the desired curvature of the mold level F to be produced (see, for example, the 7 . 9 and 10 ). For the application of the shape mirror F to form a parabolic trough, for example, a solar thermal power plant, the curvature of the desired parabolic shape follows. The predetermined curvature is thus that of a parabola. However, the invention is not limited to the formation of a parabolic shape. Rather, any shapes can be formed.

The representation in 11 shows as an example the arrangement of four frame elements 41 The invention is not limited to this number of frame elements 41 is fixed. The frame elements are to secure the parallel arrangement with a further stabilizing element 45 connected.

On the majority of substantially similar frame elements 41 For example, to form the shape-playing gel F, a metal layer is formed 30 applied, which is fixed during manufacture such that the metal layer 30 the shape of the frame elements 41 and thus the predetermined curvature takes. This is done in a similar way, as in the 2 and 3 in connection with the first embodiment with the application of the glass layer 3 is shown, wherein by the arrangement of the shaped body 40 in comparison to the shaped body 1 Retaining elements are used.

On the metal layer 30 (Back) are stabilized in the state of attachment to the above-described molded article 40 according to 12 at least two support elements 31 applied. The carrier elements 31 be on the back of the metal layer 30 , ie on the side facing away from the molding of the metal layer 30 secured by welding or preferably by gluing and permanently connected. Here, for example, a two-component adhesive can be used, which has a great long-term stability.

12 shows the arrangement of the metal layer 30 that of the shaped body 40 is detached and by the applied on the back at least two support elements 31 is held stable in the desired shape. The carrier element 31 thus serves on the one hand for shape retention, ie for obtaining the predetermined shape of the metal layer 30 of the shaped game gel F, as well as for providing means for attaching the shaped game gel to a substructure construction at the location of the insert. The representation in 12 schematically shows a shape game gel and also applies to mold mirror elements, if the mold mirror F for technical reasons (assembly, transport) is made in several parts.

According to 12 In the present example, the application of the forming mirror in a solar collector, the associated absorber tube 8th and a corresponding bracket 81 indicated. By means of the holder 81 becomes the absorber tube 8th held in the position of the focal line of the preferably parabolic solar collector, ie the mold mirror F.

On the in 12 shown metal layer 30 is on the upper side (front) in the figure, a reflective coating 32 arranged. The mirroring 32 is either as a reflective separate layer on the corresponding pretreated metal layer 30 applied, or it is the surface of the metal layer 30 polished so that the desired reflectance is achieved. The mirroring 32 is thus on the side of the metal layer 30 , which during fixing on the molding 40 in the course of production adjacent to the molding 40 is.

The metal layer 30 including the mirroring 32 may have a thickness (thickness) of about 1 mm to 3 mm. The metal layer 30 For example, may consist of a polished or coated aluminum plate or a corresponding steel plate. However, the invention is not limited to these materials. Instead of the metal layer 30 Also, a correspondingly thin plastic layer (plastic plate) can be used on the side that is on the molding 40 rests and thus to the molding 40 is adjacent, have a corresponding Verspiegelung.

The method for producing the shaping mirror F thus comprises the following measure and steps: forming a shaped body 40 with the at least two frame elements 41 , wherein the shape of the frame elements 41 which conveys a predetermined curved surface of the game play gel F, applying the metal layer 30 on the molding 40 where the metal layer 30 a surface adjacent to the molded body 40 has, on the the mirroring 32 is arranged, and applying the at least two support elements 31 on the metal layer 30 , wherein the carrier elements 31 with the metal layer 30 are connected and after separating the mold mirror F of the molded body 40 maintain the predetermined curvature. Here, the thickness of the metal layer used 30 preferably in a range of 1 mm to 3 mm.

With the arrangement and design of the mold mirror with the metal layer, the same results and advantages are achieved, as described in connection with the first embodiment.

In particular, with the use of a metal layer to form the reflection surface, a further weight reduction and, in particular, a reduction of the production costs can be achieved. It also simplifies the steps required to make the mold mirror, so that high-quality manufacturing is ensured even with simple tools and on average trained personnel.

modifications

The embodiment of the shaped mirror according to the second embodiment can also be modified in such a way that instead of the at least two support elements 31 in the manner as shown in connection with the first embodiment, a carrier layer preferably laminated in single layers (like the carrier layer 5 according to the 5 and 6 ) is applied. Again, the carrier layer is firmly connected to the metal layer and ensures the desired predetermined shape of the mold mirror. It can when using the metal layer 30 for the molded mirror, the same operations are applied to the mold mirror with the use of the glass layer 3 have been described above in connection with the first embodiment.

The present invention has been described above on the basis of exemplary embodiments in conjunction with the associated figures.

However, it should be understood by those skilled in the art that the structure of the present invention, as set forth in the foregoing descriptions, and the same reference numerals and description as well as the examples, are not to be interpreted as limiting. Also, the proportions given in the individual figures are shown schematically simplified for a better understanding. Thus, the invention is not limited to the illustrations given. Rather, all embodiments and variants are considered as belonging to the invention, which fall under the appended claims.

Claims (16)

A method for producing a shaped mirror (F), wherein the shaped mirror has a predetermined curved surface, comprising the steps of: - forming a shaped body ( 1 ), in which at least a part of its surface reproduces the surface curved in a predetermined manner, - application in a full-surface and gap-free manner of a glass layer ( 3 ) on the predetermined curved surface of the molding, wherein the glass layer has a surface ( 31 ) relative to the bearing surface to the molded body, on which a mirror coating ( 4 ), and - applying a carrier layer ( 5 ) to the mirror coating, wherein the carrier layer is connected to the mirror coating and after separating the mold mirror from the molded body maintains the predetermined curvature. Method according to claim 1, wherein the carrier layer ( 5 ) consists of a plastic material. Method according to claim 1, wherein the carrier layer ( 5 ) consists of a GfK composite material. Method according to claim 1, wherein the thickness of the glass layer ( 3 ) is in a range of 2 mm to 3 mm. Method according to one of claims 1 to 3, wherein the step of applying a carrier layer ( 5 ) the step of applying the carrier layer ( 5 ) in several individual layers ( 51 . 52 . 53 . 54 ). Method according to claim 5, wherein at least one of the individual layers ( 52 . 53 . 54 ) of the carrier layer ( 5 ) the predetermined curved surface ( 2 ) of the glass layer ( 3 ) not completely covered. Method according to one of claims 1 to 6, wherein the predetermined curved surface ( 2 ) of the shaped body ( 1 ) at least partially follows the course of a parabola. Method according to claim 7, wherein the shaped body ( 1 ) is formed such that the predetermined curved surface ( 2 ) of the shaped body reproduces at least part of the shape of a parabolic trough. Method according to claim 5 or 6, wherein the individual layers ( 51 . 52 . 53 . 54 ) of the carrier layer ( 5 ) by lamination to the mirror coating ( 4 ) are applied. Method according to claim 5, wherein at least those directly on the mirroring ( 4 ) applied single layer ( 51 ) of the carrier layer ( 5 ) is applied over the entire surface and the surface of the glass layer ( 3 ) is completely covered, and at least one of the further individual layers ( 52 . 53 . 54 ) of the carrier layer, the surface of the previously applied individual layer of the carrier layer ( 5 ) not completely covered. The method of claim 1, wherein the step of applying the carrier layer (10) 5 ) on the mirroring ( 4 ) the installation of fasteners ( 10 ) in the carrier layer ( 5 ). A method for producing a shaped mirror (F), wherein the shaped mirror has a predetermined curved surface, comprising the steps of: - forming a shaped body ( 40 ) with at least two frame elements ( 41 ), wherein the shape of the frame elements reproduces the predetermined curved surface of the shaped play gel, - applying a metal layer ( 30 ) on the shaped body, wherein the metal layer has a surface adjacent to the shaped body, on which a mirror coating ( 32 ), and - applying at least two carrier elements ( 31 ) on the metal layer, wherein the support elements are connected to the metal layer and after separating the mold mirror from the molded body maintain the predetermined curvature. Method according to claim 1, wherein the thickness of the metal layer ( 3 ) is in a range of 1 mm to 3 mm. Molding mirror comprising: a glass layer ( 3 ) having a curved shape in a predetermined manner, and wherein one of the surfaces of the glass layer is a mirror coating ( 4 ), a carrier layer ( 5 ), which are based on the mirroring ( 4 ) is applied and secured thereto, wherein the mold mirror is produced by a method according to the patent claims 1 to 11. Molding mirror comprising: a metal layer ( 30 ) having a curved shape in a predetermined manner and wherein one of the surfaces of the metal layer is a mirror coating ( 32 ), at least two support elements ( 31 ) applied to and fixed to the other surface of the metal layer, the molding mirror being manufactured by a method according to claims 12 and 13. Parabolic trough for solar collectors of a solar thermal power plant, wherein the parabolic trough has at least one shaped mirror (F) according to claims 1 to 15.

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