WO2014096482A1 - Device for securing rotating mirrors for solar radiation concentration - Google Patents

Abstract

The invention relates to a device formed by a connection part between consecutive modules of shafts of longitudinal mirrors, said connection part resting on an adjustment part in turn resting on the base part which is embedded in the foundation. The connection part is a hollow cylinder having inscribed therein the torsion prism of the first module, followed longitudinally by the second prism, also inscribed, as well as two identical diametrical plates having a thickness that matches that of the substrate of the mirror on the shaft, and a symmetrical prism in the other half-space of the cylinder, all formed in the connection part, ensuring the same rotation for consecutive modules which are balanced for rotation by means of a counterweight included in the connection part.

Description

 ROTATING MIRROR HOLDING DEVICE FOR

 SOLAR RADIATION CONCENTRATION

DESCRIPTION

Technical sector

 The invention falls within the field of solar power plants that require concentration of the original radiation, which in this case is reflected by a series of longitudinal mirrors whose longest axes are horizontal or slightly inclined, and orientable in a transverse direction by turning around a longitudinal axis, which virtually coincides with a straight surface of the mirror.

The invention is framed in the so-called solar field, which is the set of mirrors with their frames and corresponding focusing elements, to reflect the solar radiation directly from the sun on a receiver of appropriate material, either thermal, or photovoltaic; and the mirrors in question are aligned parallel to each other, forming what is called a Fresnel reflection device. Background of the invention

 The invention has an immediate background, particularly in patent ES2345427 B2, which deals with a concentrating device for solar radiation, with longitudinal mirrors, rotating around its longest axis, these axes being parallel to each other and parallel in turn to the face. activates the receiver in its longitudinal direction. The first inventor of said patent is the same who signs the present application.

In the aforementioned document several other antecedents of this type of assembly are analyzed, which are simply described here, since they refer to the configuration of the mirror field, but none addresses in constructive detail the devices that hold the mirrors, at the same time as They allow them to rotate freely on their axis of rotation. Classical patents include WO 99/42765, BE 1 013 565 A3 and BE 1 013 566 A3; and as more recent patents WO 2009/029277 A2 and 2009/023063 A2; and other noteworthy patents are WO 2006/000834 A1, WO 02/12799 A2, WO 02/12799 A2 and EP2161516 A1. Like other direct antecedents, of which the applicant is also an inventor, it is worth mentioning patents ES2346629 and ES2356221, this being The last one is dedicated to solar tracking in its daytime trajectory, maintaining the focus of the radiation reflected on the receiver, but without providing data on the supports of the mirror axes. Technical problem to solve

 To correctly approach the sun with the longitudinal Fresnel reflection systems, it is imperative that the mirrors rotate around an axis that, as anticipated, coincides with a longitudinal line on the specifically specular surface. But in turn the mirrors are made by successive longitudinal modules, which must virtually share the shaft, which in turn must have a real mechanical support for the assembly to rotate.

Therefore, the problem to be solved is to provide mirrors with axes and axes with supports, which meet the movement requirements of the mirror and its axis, in the successive modules that constitute it. Note that the mirrors can be several hundred meters, and the modules 10 m long or so, so it requires several devices that support the modules at their ends, and in turn give continuity to the axis, which logically can not have a light of several hundred meters, and you need intermediate supports, which make up a device that meets the requirements presented.

Description of the invention

 The invention comprises a base piece or foot of the support, topped off by a semi-cylindrical adjustment piece of semicircular section, on which rests the connecting piece, which is circular cylindrical, within which the components are assembled. following elements:

 torsion prism of the module prior to the support considered, counting said modules in the sense of their assembly, this prism being square or rectangular, with an internal hollow; and the base of the mirror being jointly and severally attached to it by one of the faces of the prism, which we call the upper face;

torsion prism of the module following the support considered, of characteristics equal to the previous prism, or first prism and extending in its extension; diametral plate arranged on both torsion prisms, the upper face of said plate coinciding with the horizontal diameter of the connecting piece, when the torsion prisms are in the reference position, which is the position of keeping the modules facing upwards. mirrors, said diametral plate having a thickness coinciding with that of the base plate or substrate of the mirror at its midpoint:

 symmetric diametral plate, of the same thickness as the diametral plate, and located above it in the reference position;

 symmetric prism, with a straight section equal to that of the aforementioned torsion prisms, located this symmetric prism above the diametral symmetric plate, in the reference position;

 the lengths of the symmetrical prism and the diametral plates being equal to the length of the connecting piece, with a clearance of plus or minus five percent;

leaving the torsion prisms, plus the diametral plates, plus the symmetrical prism, inscribed on the inner face of the connecting piece, and integral with it by its vertices, either by welding, or by adhesive, depending on the nature of the pieces, selected from metallic, plastic, fiberglass or other fibers and composites.

All the pieces inscribed in the connection piece and the connection piece itself are drilled in a vertical direction, measured in this direction in the reference position, at least by two sets of matching holes, each of said sets of holes being pierced by a pin that crosses from top to bottom, and that is attached by each end to the outer face of the connecting piece, by means of a tightening thread with its pressure washer.

At the top of at least one hole at each end, being in the reference position, a counterweight is located on the outer face of the connecting piece, said counterweight being also drilled, and held by the upper clamping thread of the corresponding pin , which therefore clings to the counterweight, which in turn presses on the outer face of the connecting piece. The mass of the counterweight and the distance from its center of mass to the axis of rotation of the system, which is the axis of the cylinder that constitutes the connecting piece, is such that its product equals the product of half the mass of the previous module mirror, including all the elements suspended with the torsion prism, and the prism itself, multiplied said mass by the perpendicular distance from the center of mass of that particular suspended mass, to the axis of rotation of the system, which coincides with the axis of rotation of the mirror.

Around the outer face of the connection piece a ring or flange is grounded, integral with the connection piece itself by welding or adhesive cord.

The connection piece rests and can rotate on the semicircular part of the adjustment part, which has a transverse groove in which the ring or flange flap is housed, said adjustment part containing rollers with longitudinal axis, on which the connection piece truly rests on its outer face, said rollers being able to rotate freely as the connection piece rotates on them.

In one of the interior vertices of the symmetrical prism is located a tube of diameter of the order of the millimeter, which constitutes the longitudinal collimation peephole of the axle support devices.

The adjustment piece is integral with the base piece or support foot, having on one side of its semicircular shape a support mechanism with rotation around a bolt embedded in the base piece, and which acts as the axis of the small turn that it is performed to adjust the height of the adjustment piece to the level given by the longitudinal collimation of the axes of the modules; said adjustment piece being supported on the base piece by the other end, by means of a screwed through rod, which crosses both pieces through vertical grooves, the rod being held by its ends when the height produced by the collimation of the axes, testified by a beam of laser light; complementing the lift by means of a pin nail that is located through the corresponding holes made in the vertical walls of the adjustment piece and the base piece. When the bending moment is very large in the support, which is largely absorbed by the connecting piece and the ring, the base piece is made of two pairs of legs, the counterweights are located in the center of the piece of connection, clinging to the zuncho ring, and the rollers are located outside the counterweights on each side, using a pin rod to fix the adjustment piece to the base, once the collimation is verified.

When the mechanical reaction in the supports allows it, or when it is decided by constructive simplification even at the risk of wear, the connecting piece slides, in its follow-up turn to the sun, on fixed raceways at the longitudinal ends of the adjustment piece, which clings to the base part by means of a pin rod, with no rollers in this variant.

There is another more elementary variant, for when the bending moment in the support is not very strong, which consists in that the connecting piece, the counterweight, the symmetrical prism, the diametral plates and the two torsion prisms are crossed and held by a only central pin rod, with no zuncho ring in this variant. Brief description of the drawings

 The figures, in general, are not to scale, since the relative sizes of the elements are very different; and its proportions must be violated so that the explanations are intelligible. Figure 1 shows a diagram, in straight section, of the solar device, corresponding to a Fresnel reflection assembly with rotating mirrors.

Figure 2 shows the three-dimensional scheme of a receiver-mirror assembly in the assembly according to the parallel, arranged north of the parallel in the northern hemisphere.

Figure 3 shows a cross-section of a mirror, although instead of a torsion prism, the mirror is supported by a solid semi-cylinder, which can act as a torsion box, but does not have the ideal moment of inertia to reduce deformations of the module by flexion. Figure 4 shows a cross-section of a mirror that has been provided with a torsion prism, which gives the mirror module greater rigidity when it rotates.

Figure 5 shows a longitudinal section of the connection piece with its internal elements and its support in the adjustment piece.

Figure 6 schematically shows the straight section of the connection piece with its associated elements.

Figure 7 shows the connection of the adjustment piece in the base piece, and the reception of the connection piece in the adjustment piece.

Figure 8 shows a longitudinal section of the connection piece and its support in the adjustment piece, and of this one adjusted to the base part, when the base part has two pairs of legs, having omitted part of the complete information given in the Figure 5, for the sake of clarity in the explanation of this assembly variant of the invention, although logically all the elements already mentioned are logically inside the connection piece.

Figure 9 shows a longitudinal section of the connection piece and its support in the adjustment piece, and of it adjusted to the base part, using a sliding raceway, instead of rollers, on the face of the part of adjustment on which the connection piece rests.

Figure 10 shows a longitudinal diagram of the connecting piece with a single central pin rod gripping all its internal elements plus the counterweight, with no ring in this variant.

Preferred embodiment of the invention

 In order to facilitate the understanding of the figures of the invention, and of their embodiments, the relevant elements thereof are listed below:

 1. Solar radiation receiver,

 2. Active surface or face of the receiver (1), where concentrated solar radiation is absorbed.

 3. Center point of the segment that represents the active face (2) of the receiver (1), in a plane perpendicular to the axes.

4. Direct solar radiation. Longitudinal mirror that reflects the original solar radiation on the receiver (1), and that is closer to the receiver.

Solar radiation reflected by the mirrors (7).

Generic mirrors that reflect solar radiation (4) on the receiver (1). There is a plurality of parallel mirrors in all of them, which reflect the radiation on the same receiver (1).

Staffs or tall pillars that keep the radiation receiver and its internal elements in its height and position.

Low pillars that keep the axes of the mirrors in their height and position, generically represented by (7).

Longitudinal axis of a generic mirror (7), around which it rotates to acquire the precise transverse inclination for solar focusing.

Rotating connection, thanks to the device, of the abutment (9) with the axis (10) of rotation of the generic mirror (7). It is the fundamental object of this invention.

Firm holding part of the receiver (1) to the staff (8).

Transverse bracing cables of the pillars or rods (8).

Upper cross member for stiffening the receivers (1).

Interior elements of the receiver (1), either thermal, or photovoltaic. They are not relevant to the invention.

Ground.

Normal line to a mirror, which is the bisector of the angle of reflection.

Rotation axis of a specific mirror, figure 3, which coincides with the center point of the mirror itself.

Substrate or mirror holder.

Torsion bar, which in this case is a solid semi-cylinder, because it corresponds to the previous state of the art, which in this invention is replaced by a true prism.

Reflected ray that goes from the right end of a given mirror, figure 3, to the center point of the receiver surface, 3.

Reflected ray that goes from the left end of a given mirror, figure 3, to the central point of the receiver surface, 3.

Reflected ray that goes from the central point of a given mirror, figure 3, to the central point of the receiver surface, 3.

Substrate or base of the mirror that is supported by the torsion prism (26) of that module at its midpoint, that is, under the axis. 25. Mirror mirror surface at its midpoint, that is, on the axis.

 26. Torsion prism of that mirror module.

 27. Diametral plate with thickness equal to that of substrate 24.

 28. Diametric symmetric plate.

29. Symmetric prism.

 30. Cylindrical connection piece.

 31. Adjustment piece, on which the connection piece 30 rests and rolls (turning).

32. Rollers of free rotation with fixed shafts in the adjustment piece, on which the connecting part rotates, 30.

33. Roller shafts 32.

 34. Torsion prism of the next module.

 35. Notch in both torsion prisms, 26 and 34, which also serves as a dilation space.

 36. Counterweight.

37. Pin rod.

 38. Head, fixed or threaded, of the pin shank, 37.

 39. Head pressure washer 38.

 40. Zunchado ring or fin.

 41. Notch in adjustment piece 31, where ring 40 is housed.

42. Head, threaded or fixed, of the pin shank, 37, opposite head 38.

 43. Head pressure washer 42.

 44. Welding bead, or adhesive bead, of union between each diametral plate and the connecting piece, 30,

 45. Longitudinal collimation sight glass.

46. Upper part of the base piece or support foot.

 47. Bolt that acts as an axis for the rotation of the adjustment piece, 31, when adjusted in height by longitudinal collimation.

 48. Drills to accommodate the through-pin for fixing the clamping height.

49. Slot to enable the best fit of the adjustment piece 30.

50. Through screw to fix the height of the adjustment piece, 30.

 51. Double plate, on both sides, of the adjustment piece 30, which hugs the upper part of the base piece 46.

 52. Legs of the base piece

 53. Cross stiffening arms

54. Foundation 55. Pin rod for fixing the counterweight 36 to the ring 40.

 56. Pin fixing rod of the adjustment piece 31 on the base piece, when it has two pairs of legs (58).

 57. Retaining tab of connection piece 30.

 58. Legs of the base piece when it has two pairs.

 59. Raceway in the adjusting part 31 on which the outer face of the connecting piece 30 slides.

 60. Central pin rod.

 61. Head of the central pin rod.

 62. Threaded or robbed closure of the central pin rod.

For the application of the invention and its materialization it is necessary to select the type of material to be used and, above all, to know what weight per unit of length the mirrors have. As for materials, common construction steel is selected for this application, due to its availability and good price. Its two characteristics involved in this application are its modulus of elasticity, E, which is worth 2, 1 - 10 ¹¹ N / m ² , and its specific weight p = 77 kN / m ³ . The prisms are defined by its side of the straight section, which is a square, and the thickness of its walls. Next to the square it will be identified by b, and the thickness will be taken as 0.03 b, which allows us to solve the problem of applying the invention analytically. Another essential parameter is the moment of inertia, I, that in the reference position, that is, with the mirrors facing the zenith, and with the assumption made on the thickness, it is necessary to

I = 0.0183 b ⁴ And the weight of the prism per unit length, w _p , always using the SI system of units, is

w _p = 9240- b ²

The arrow f of a recessed beam at its ends, of length L and which is subjected to a linear load w (N / m) is

f = w L ^4/384 EI

where the load w is the sum of the linear weight of the prism, plus the weight of the mirror and its supports. In this case we assume a silver mirror, on a rigid plastic plate 2 mm thick, with a density of 1 kg / dm ³ and a transparent glass cover of another 2 mm, with a density of 2.5 kg / dm ³ , to which is added the Weight of 4 triangular frames also of plastic, 10x25x2 cm, which gives a linear weight of 60 N / m, to which we must add w _p , which is still unknown, it depends on the prism that is needed.

To finish defining this application, it is established that the arrow corresponds to an angular deformation from an end that is equal to 2 millirads, which means f = (L / 2) 0.002 = L / 1000

By matching this expression to the general arrow, the equation is obtained

w _p + 60 = 0.384- E l / L ³

and setting L = 10 m, and using the values of I and w _p as a function of b, we arrive at the following bi-quadratic equation in b

1, 47-10 ⁶ b ⁴ - 9240 b ² -60 = 0 Whose solution is b ² = 0.01 and therefore b = 0.1 m; to which corresponds a linear load of the prism of 92 N / m, which added to that of the mirror gives 152 N / m. What matters to size the device is the size of the prism, which is 10 cm side and 3 mm thick. With the above-mentioned mirror, the diametral plates must be 2mm thick each. which leads to an inner radius of the connecting piece that is (6.2 ² + 3 ² ) ^{1 2} in cm, which gives 6.9 cm. Its thickness must be commensurate with the torque that has to support that support, which functions as recessed, because the piece does not allow the prism to rotate freely, being the bending moment M, in the support,

M = wL ^2/12 With 152 N / m and L = 10 m, is 1267 N m. With a diameter of 14 cm and a similar value in the length of the connecting cylinder, the tensions to be absorbed are 9000 N. Taking as a permissible value 1000 N / cm ² , 9 cm ² of straight section are needed in each semicircle, whose Length is 22 cm, so a minimum thickness of 0.4 cm would be required. The length of the connection piece can be of the order of its diameter, about 15 cm, for the absorption of the bending moment. As for the weight of the counterweight, it has to balance 152 N / m by 5 meters, and taking into account that the center of mass is approximately 2/2 of the axis of rotation, there is a torque of 38 N m. As the center of mass of the counterweight will be at a distance of about four times the radius, a weight of 38 / 0.28 remains, which gives 135 N, that is, about 13 kg. If lead is used as a counterweight, it would take just over a liter, 1, 20 dm ³ , which It corresponds to a box of 14X14X6 cm, which is of the order of size of the device itself.

To assemble it, the first prism would have to be placed inside the connecting cylinder, put the two diametral plates presented, insert the symmetrical prism, present the secondary or shaft extension prism, and finish fitting the diametral plates, after which fixed with welding, once the through rods have been put on, including the clamping of the weights. Once the assembly of the connection piece is completed, it must be located at the corresponding height, for which the collimator is provided, inside which the used laser beam must pass. When the collimation is fulfilled, the screw is tightened by gripping the adjustment piece to the base, and immediately passes the through nail from one side to the other of the plates (51) making these two pieces in solidarity, and resting the piece of connection on the rollers of the one of adjustment, what guarantees the functionality of the axis, extended a module after another.

Once the invention is clearly described, it is noted that the particular embodiments described above are subject to modifications in detail as long as they do not alter the fundamental principle and essence of the invention.

Claims

1 -Rotating mirror clamping device for concentration of solar radiation, applicable to a set of mirrors (7) slightly concave upwards, parallel to each other, of markedly longitudinal geometry, that is, with a length much greater than its width, each of them rotating around its axis of longitudinal symmetry (10), which in turn is the axis of the physical system with which the mirrors sit on the pillars (9) that, each certain length of length, are interlocked in the ground and each rigidly support its corresponding clamping device, characterized in that each device comprises a base piece or foot of the support, topped off by a semi-cylindrical adjustment piece of semicircular section, on which the piece rests of connection, which is of circular cylindrical form, within which the following elements are assembled, torsion prism of the module prior to the considered support, counted s said modules in the sense of their assembly, this prism having a square or rectangular section, with an internal hollow; and the base of the mirror being jointly and severally attached to it by one of the faces of the prism, which we call the upper face;  torsion prism of the module following the support considered, of characteristics equal to the previous prism, or first prism, and extending in its extension;  diametral plate arranged on both torsion prisms, the upper face of said plate coinciding with the horizontal diameter of the connecting piece, when the torsion prisms are in the reference position, which is the position of keeping the modules facing upwards. mirrors, said diametral plate having a thickness coinciding with that of the base plate or substrate of the mirror at its midpoint:  symmetric diametral plate, of the same thickness as the diametral plate, and located above it in the reference position; symmetric prism, with a straight section equal to that of the aforementioned torsion prisms, located this symmetric prism above the diametral symmetric plate, in the reference position; the lengths of the symmetrical prism and the diametral plates being equal to the length of the connecting piece, with a clearance of plus or minus five percent; leaving the torsion prisms, plus the diametral plates, plus the symmetrical prism, inscribed on the inner face of the connecting piece, and integral with it by its vertices, either by welding, or by adhesive, depending on the nature of the pieces, selected from metallic, plastic, fiberglass or other fibers and composites. 2 - Device for fastening rotating mirrors for concentration of solar radiation, according to claim one, characterized in that all the parts inscribed in the connection piece and the connection piece itself are drilled vertically, measured in this direction in the reference position , at least by two sets of coincident holes, each of said sets of holes being crossed by a pin that crosses from top to bottom, and that is attached by each end to the outer face of the connecting piece, by means of a tightening thread with your pressure washer 3 - Device for fastening rotating mirrors for concentration of solar radiation, according to any of the first and second claims, characterized in that a counterweight is placed on the top of at least one hole at each end, being in the reference position. the outer face of the connecting piece, said counterweight being also drilled, and gripped by the upper clamping thread of the corresponding pin, which therefore clings to the counterweight, which in turn presses on the outer face of the connecting piece; being the mass of the counterweight and the distance from its center of mass to the axis of rotation of the system, which is the axis of the cylinder that constitutes the connecting piece, such that its product equals the product of half the mass of the previous module of mirror, including all the elements suspended with the torsion prism, and the prism itself, multiplied said mass by the perpendicular distance from the center of mass of that particular suspended mass, to the axis of rotation of the system, which coincides with the axis of rotation of the mirror. 4 - Device for holding rotating mirrors for concentration of solar radiation, according to any of the preceding claims, characterized in that around the outer face of the connecting piece a ring or flange is threaded, integral with the connection piece itself by welding or adhesive bead. 5 - Device for securing rotating mirrors for concentration of solar radiation, according to any of the preceding claims, characterized in that the connection piece rests and can rotate on the semicircular part of the adjustment part, which has a transverse groove in the one that houses the ring or flange flap, said adjustment piece containing rollers with longitudinal axis, on which the connection piece really rests on its outer face, said rollers being able to rotate freely as the part of them rotates on them Connection. 6 - Device for securing rotating mirrors for concentration of solar radiation, according to previous claims, characterized in that in one of the inner vertices of the symmetrical prism a tube of diameter of the order of the millimeter is located, which constitutes the longitudinal collimation sight glass of axle lift devices. 7 - Device for holding rotating mirrors for concentration of solar radiation, according to previous claims, characterized in that the adjustment piece is integral with the base piece or support foot, having on one side of its semicircular shape a mechanism for lift with rotation around a bolt embedded in the base piece, and which acts as the axis of the small turn that is made to adjust the height of the adjustment piece to the level given by the longitudinal collimation of the axes of the modules; said adjustment piece being supported on the base piece by the other end, by means of a screwed through rod, which crosses both pieces through vertical grooves, the rod being held by its ends when the height produced by the collimation of the axes, testified by a beam of laser light; complementing the lift by means of a pin nail that is located through the corresponding holes made in the vertical walls of the adjustment piece and the base piece. 8 - Device for fastening rotating mirrors for concentration of solar radiation, according to any of the preceding claims, characterized in that the base piece is made of two pairs of legs, the counterweights are located in the center of the connecting piece, clinging to the zuncho ring, and the rollers are located outside the counterweights on each side, using a pin rod to fix the adjustment piece to the base, once the collimation is verified. 9 - Device for securing rotating mirrors for concentrating solar radiation, according to any of the preceding claims, characterized in that the connecting piece slides, in its sun-tracking turn, on fixed raceways at the longitudinal ends of the adjustment piece, which clings to the base part by means of a pin rod, with no rollers in this variant. 10 - Device for securing rotating mirrors for concentration of solar radiation, according to any of the preceding claims, characterized in that the connection piece, the counterweight, the symmetric prism, the diametral plates and the two torsion prisms are crossed and held by a single central pin rod, with no zuncho ring in this variant.