AU2012201674A1

AU2012201674A1 - Support arm, cylindrical-parabolic solar collector support and method of producing said arm

Info

Publication number: AU2012201674A1
Application number: AU2012201674A
Authority: AU
Inventors: Miguel Domingo Osle; Jorge Vazquez Ingelmo
Original assignee: Sener Ingenieria y Sistemas SA
Current assignee: Sener Ingenieria y Sistemas SA
Priority date: 2005-09-19
Filing date: 2012-03-21
Publication date: 2012-04-12
Anticipated expiration: 2026-07-18
Also published as: AU2012201674B2; AU2012201674C1; AU2012201674B9

Abstract

The invention relates to a support arm for a cylindrical-parabolic collector, which is intended to be coupled to a central body (1) of the collector in the form of a bracket in a direction that is substantially perpendicular to a focal line (2) of the collector. The 5 inventive arm takes the form of a wedge comprising: a first side (10) which is provided with support devices (11) for supporting at least one mirror (3), a second side (20), and a third side (30) which is provided with support devices (31) such that the arm is supported by the central body (1). The arm is formed by at least one press-formed plate such as to obtain a resistant structure that provides stiffness and a carrying 10 capacity by means of a plurality of ribs (42) which form a lattice comprising a plurality of laminar segments (41) between said ribs.

Description

Australian Patents Act 1990- Regulation 3.2A ORIGINAL COMPLETE SPECIFICATION STANDARD PATENT Invention Title: "SUPPORT ARM, CYLINDRICAL-PARABOLIC SOLAR COLLECTOR SUPPORT AND METHOD OF PRODUCING SAID ARM" The following statement is a full description of this invention, including the best method of performing it known to us: C \NRPonbl\DCC\PL\V4224481 I DOC 1 SUPPORT ARM, CYLINDRICAL-PARABOLIC SOLAR COLLECTOR SUPPORT AND METHOD OF MANUFACTURING THE ARM Field of the Invention 5 The invention relates to a component and to a method for manufacturing said component used in thermal solar plants, in which a fluid (air, water vapor, oil or salts) is heated by means of optical concentration. This fluid moves a turbine or in turn heats another fluid which is responsible for carrying out this task. Nevertheless, the collectors which will be described can also be used in combination with photovoltaic panels. 10 Background of the Invention Cylindrical-parabolic solar collector plants are found within the different types of thermal solar plants. In these types of plants the thermal fluid traverses a straight pipe located in the actual focus of an extruded parabola. This parabola, the longitudinal axis of which can be oriented in a north-south or east-west direction, is in turn able to rotate 15 on a single axis to optimize the incident radiation in the opening area of the collector. Normally the dimensions of a collector of this type are usually around 100-150 meters in state-of-the-art collectors. These collectors, which move by means of a hydraulic mechanism, are formed in turn from several segments the length of which is about 12 meters. 20 Several methods for manufacturing the arms in the state of the art can be pointed out: 1. Arms made based on welded tubes: Until now, the arms on which the mirrors are supported have been made from tubes welded to one another forming a small lattice. However this manufacturing 25 method, providing a light and strong structure in the end, creates two fundamental drawbacks: - The manual labor associated to the cutting and welding of the tubes makes the end product considerably more expensive. - The precision finally obtained at the support points of the mirrors is not enough to 30 directly support the mirrors. To that end it is necessary to use intermediate metal parts secured to the arm by means of guides which are finally adjusted to the desired position with the aid of a tool. This operation also has its impact on the final cost of the part. 2. Other alternatives: 35 There are other alternatives for manufacturing arms for supporting the mirrors of 2 cylindrical-parabolic collectors which can be emphasized: - Using fiber panels, sandwich panels or the like for generating very light and sufficiently resistant structures. - Using continuous structures which prevent using arms. 5 The arms must also fulfill a series of characteristics: 1. Geometric characteristics: There are different arrangements of the bars for forming the arm depending on the loads for which the collector is sized, the position of the latter within the field and the measurements of the central case and of the original parabola forming the mirrors. 10 2. Physical characteristics: The following can be emphasized among the most important: - Weight of the arms: Between 10-14 kg/part. - Superficial treatment: Hot galvanizing. - Types of profiles used: normally a tubular profile having a thin wall (thickness 1-2 15 mm). The field collector, i.e. the set of all collectors collecting solar radiation in order to heat the oil, is a fundamental part in these types of stations. The collectors in which the mirrors are supported are made based on a metal structure, normally galvanized steel, and must fulfill the following requirements: 20 - On one hand they must provide enough precision to position the mirrors such that they concentrate all the radiation on the geometric focus of the theoretical parabola. - On the other hand, and given the large dimensions which these stations usually have, the metal structure must be inexpensive, simple to manufacture and long lasting. 25 Throughout the history of these plants, different types of structures capable of satisfying, to a greater or lesser extent, these requirements have been developed. Two types of support structures can fundamentally be distinguished between. - Collectors made based on what could be called "spatial structure". In these collectors, the support structure forms a continuous whole extending through the 30 entire rear part of the parabola. In these types of structures there is no distinction between central body and arms, all forming a monoblock assembly. - Collectors formed by a central body and arms supporting the mirrors. In these types of collectors the structure can be separated into two parts. On one hand is the central body fundamentally supporting the bending and torsion loads. This central 35 body can be made based on a welded tube or by means of a framework of bars.

C:V4RPonbrlJ\DCAX LUL )5IX L UUL-/I J110 3 Arms are fastened to this central body which are responsible for supporting the parabolic mirrors. Embodiments of the invention relate to these arms, to the central body and to the method for manufacturing said arms. 5 Summary of the Invention A first aspect of the invention relates to a support arm for a cylindrical-parabolic collector configured to be coupled to a central body of the collector in the form of a bracket in a direction that is substantially perpendicular to a focal line of the collector, said arm 10 having a wedge shape having: a first side provided with support means for supporting at least one mirror; a second side; a third side provided with support means so that the arm is supported by the central body; 15 said arm being characterized in that it comprises: at least one press-formed plate formed to obtain a resistant structure in order to provide stiffness and carrying capacity by means of a plurality of ribs forming a lattice having a plurality laminar segments between said ribs. 20 The plate can be galvanized. In the arm of the invention the plate can be galvanized. The plate can also have a thickness comprised between 1-2.5 mm. The thickness of the plate can preferably be comprised between 1.2-2 mm. In the arm of an embodiment of the invention the support means of a mirror can be 25 separated a distance a, and: the first side can have a length comprised between 2.1-3.2a; the second side can have a length comprised between 2.3-3.4a; the third side can have a length comprised between 0.8-1.2a; the end support means can be at a distance comprised between 0-0.6a of the 30 ends of the first side. Additionally, in the arm of an embodiment of the invention, the adjacent support means of two mirrors can be at a distance comprised between 0.4-0.6a. The support means of the arm of an embodiment of the invention can comprise four seats of the mirror.

CNRPortbn)CLAXL\3252,I1. UUt*1 I /lZU 4 In addition, in the arm of an embodiment of the invention, the support means can comprise two fixings to the central body configured to allow disassembling the arm from the central body, it being possible for said fixings to be located in: a first vertex at which the first side and the third side converge; 5 a second vertex at which the second side and the third side converge. The arm of an embodiment of the invention can further optionally comprise at least one cavity in the laminar segment for lightening. Likewise, in the arm of an embodiment of the invention the first side can be concave curved in order to have a shape adapted to the semi-parabolic shape of the at 10 least one mirror. The second side of the arm can likewise be convex curved in order to reach an optimal strength/weight ratio. The third side of the arm can also be concave curved, having a prominent concavity for lightening. 15 In the arm of an embodiment of the invention, the plurality of ribs can form a lattice having a framework selected among triangular, trapezoidal and combinations thereof. A second embodiment of the invention relates to a support for a cylindrical parabolic collector which can comprise at least one arm as described above and a tube shaped central body formed from a planar plate for: 20 providing torsional stiffness; minimizing the number of fixings to the arm; facilitating the assembly/disassembly of the arm. A third embodiment of the invention relates to a method for manufacturing an arm according to that described above, said process comprising: 25 a) cutting a plan of an arm in a planar plate for obtaining an initial shape; b) press-forming the initial shape in order to form a resistant structure to provide stiffness and carrying capacity by means of a plurality of ribs forming a lattice having a plurality of laminar segments between said ribs to obtain a final shape. The method can further comprise: 30 c) punching the final shape in order to place the support means. The method can also additionally comprise: d) punching the final shape in order to place the support means.

C: WPorblDCC\AXLU252817_1.DOC-26/ i/2f10 4a The method for manufacturing the arms of an embodiment of the invention has the following advantages: - The number of operations necessary in order to arrive at the end product from the raw material is not high, said operations further being very easily automated, which 5 translates into a lower cost. - Mass producing these types of parts results is higher quality and a greater 5 repetitiveness of the features of the end product by reducing the number of rejections. - The need to adjust the supports is eliminated since the part with the support points is manufactured according to the required precision, reducing the assembly cost. 5 Brief Description of the Drawings A series of drawings will be very briefly described below aiding to better understand the invention and which are specifically related to an embodiment of said invention, presented as non-limiting example thereof Figure 1 is a scheme showing a cylindrical-parabolic collector. 10 Figure 2 is a side view showing a cylindrical-parabolic collector according to the invention. Figure 3 is a view of an arm of the invention in which the geometry of the arm is indicated. Figures 4A, 4B and 4C show three alternative designs of an arm according to 15 the invention. Figure 5 is a perspective view of a portion of a collector in which a plurality of arms supporting a plurality of mirrors is shown, said arms being connected to a central body. Description of a Preferred Embodiment of the Invention 20 More than 200,000 arms may be necessary in a commercial solar plant. This huge quantity of necessary units forces the process by means of which these elements are manufactured to be extremely simple in order to lower costs without loosing the capacity of these elements to absorb loads and to provide suitable stiffness and precision. 25 To that end the arms, which are coupled to the central body 1 of the collector in the form of a bracket in a direction that is substantially perpendicular to the focal line 2 of said collector, have a wedge shape having a first side 10 having the support means 11 for supporting the mirrors 3, a second side 20 and a third side 30 having the support means 31 so that the arm is supported by the central body 1. In the invention, the arm 30 is formed from at least one press-formed plate formed to obtain a resistant structure in order to provide stiffness and carrying capacity by means of a plurality of ribs 42 forming a lattice having a plurality of laminar segments 41 between said ribs 42. These laminar segments can have cavities 43 made in order to lighten the weight of the arm. The invention also relates to manufacturing parts from a press-formed plate. 35 This process starts from a planar plate with a thickness of between 1 mm and 2 mm.

6 This plate is subjected to successive die-cutting and matrix actions giving it shape in order to achieve the required consistency of the final part. The definitive housings or support means 11 for placing the mirrors 3 can be carried out on the press-formed part during the manufacture process. This allows achieving the required precision for the definitive 5 anchoring of the mirrors 3 in positioning these housings or support means 11. The fundamental operations comprised in the method are therefore: - Cutting a planar plate with suitable thickness in order to obtain a desired initial shape. - Performing successive press-forming/die-cutting operations for forming the planar 10 plate to the desired shape with a series of ridges or ribs 42 providing the required strength and stiffness. - The holes or support means 11 supporting the mirrors 3 and the support means 31 anchoring the arm to the central body 1 of the collector are positioned by means of punching or an equivalent operation with enough precision so that additional 15 adjustment operations do not have to be carried out. In an embodiment of the invention the design of the collector with press-formed arms is optimal in terms of performance and cost if a tube formed from a welded plate is used as a central body 1. Plates with thicknesses comprised between 1.2 mm and 2 mm can be chosen for the arms depending on the wind loads which the specific collector will 20 undergo due to its position in the field. Throughout this specification and the claims which follow, unless the context requires otherwise, the word "comprise", and variations such as "comprises" and "comprising", will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers 25 or steps. The reference in this specification to any prior publication (or information derived from it), or to any matter which is known, is not, and should not be taken as an acknowledgment or admission or any form of suggestion that that prior publication (or information derived from it) or known matter forms part of the common general knowledge 30 in the field of endeavour to which this specification relates.

Claims

1. A support arm for a cylindrical-parabolic solar collector configured to be coupled to a central body of the collector in the form of a bracket in a direction that is substantially 5 perpendicular to a focal line of the collector, said arm having a wedge shape having: a first side provided with support means for supporting at least one mirror; a second side; a third side provided with support means so that the arm is supported by the central body; 10 said arm being characterized in that it comprises: at least one press-formed plate formed to obtain a resistant structure in order to provide stiffness and a carrying capacity by means of a plurality of ribs forming a lattice having a plurality laminar segments between said ribs. 15

2. The arm of claim 1, characterized in that the plate is galvanized.

3. The arm of any of claims 1-2, characterized in that the plate has a thickness comprised between 1-2.5 mm. 20

4. The arm of claim 3, characterized in that the plate has a thickness comprised between 1.2-2 mm.

5. The arm of any of claims 1-4, characterized in that the support means comprises 25 four seats of the mirror.

6. The arm of any of claims 1-5, characterized in that the support means comprise two fixings to the central body configured to allow disassembling the arm from the central body, said fixings being located in: 30 a first vertex at which the first side and the third side converge; a second vertex at which the second side and the third side converge.

7. The arm of any of claims 1-6, characterized in that it further comprises at least one cavity in the laminar segment for lightening. C \NRPonbrDCC\AXLU2521_ .DOC-26111/2010 8

8. The arm of any of claims 1-7, characterized in that the first side is concave curved in order to have a shape adapted to the semi-parabolic shape of the at least one mirror. 5

9. The arm of any of claims 1-8, characterized in that the second side is convex curved in order to reach an optimal strength/weight ratio.

10. The arm of any of claims 1-9, characterized in that the third side is concave curved having a prominent concavity for lightening. 10

11. The arm of any of claims 1-10, characterized in that the plurality of ribs forms a lattice having a framework selected from triangular, trapezoidal and combinations thereof.

12. A support for a cylindrical-parabolic solar collector characterized in that it 15 comprises at least one arm according to any of the claims 1-11 and a tube shaped central body formed from a planar plate for: providing torsional stiffness; minimizing the number of fixings to the arm; facilitating the assembly/disassembly of the arm. 20

13. A method for manufacturing an arm according to claims 1-11, characterized in that it comprises: a) cutting a plan of an arm in a planar plate for obtaining an initial shape; b) press-forming the initial shape in order to form a resistant structure to 25 provide stiffness and carrying capacity by means of a plurality of ribs forming a lattice having a plurality of laminar segments between said ribs to obtain a final shape.

14. The method of claim 13, characterized in that it further comprises: 30 c) punching the final shape in order to place the support means.

15. The method of any of claims 13-14, characterized in that it further comprises: d) punching the final shape in order to place the support means. C :NRPorbWlDCC\AXLU2317_ 1.U-0/ I 1/-"1" 9

16. A support arm for a cylindrical-parabolic solar collector substantially as hereinbefore described with reference to the accompanying drawings.