JP5253420B2 - Solar concentrator - Google Patents

Description

  The subject of the present invention is called the “first image focus”, so to speak a focusing lens such as a collector, which itself has a focal length and an image focal plane, the rays of the received sun rays, said lens moving with the orbit of the sun It is a solar concentrator of the type provided with the said condensing line. Such a lens is said to be “linear” and its focal point is a straight line.

  In view of changes in the direction of the sun's rays in the daily and seasonal paths, known solar concentrators use expensive parabolic mirrors or are included in swivels or complex and fragile motor devices Either.

  The present invention proposes to provide a simple and effective solution to remedy these drawbacks.

For this purpose, the present invention provides that the converging lens forms one of the walls of the chamber defined by two pairs of side walls, a bottom wall and a front wall formed by the lenses, and each pair of side walls is mutually connected. Parallel, perpendicular to the other,
The sidewall and bottom wall inside the chamber are reflective;
The depth p between the front wall and the bottom wall is smaller than the focal length f of the lens,
After multiple reflections, the fully reflected light beam is symmetric with respect to the first image focal plane with respect to the bottom wall and is symmetric with respect to the image focal plane with respect to the bottom wall and is located within the chamber. It is concentrated on a straight line called “final image focal point” belonging to “near image focal plane distance”,
The concentrator includes a movable photoreceiver maintained within the focused light beam or at least a position that divides the light beam by servo-controlling movement of the receiver to movement of the light beam. Providing a solar concentrator of the type described above.

  In a preferred embodiment, the front and bottom walls of the chamber are perpendicular to the side walls, in other words, the chamber takes the form of a right-angled parallelepiped.

In this particular case, the chamber depth p satisfies the following relationship:
p = 0.5 * (f + e + b)
Where e is the penetration thickness of the lens in the chamber, and b is the distance or effective operating distance between the lens and the near image focal plane.
The concentrator includes a movable light receiver that is maintained within the concentrated light beam, or at least at a position that divides the light beam by servo-controlling movement of the light receiver to movement of the light beam. .

  Thus, the structure of the concentrator according to the invention makes it possible to follow the orbit of the sun by servo-controlling the position of the photoreceiver in the chamber rather than the orientation of the chamber on this orbit. Yes. Judging from this, on the one hand, the servo control means is significantly lighter when the entire chamber needs to be moved, and on the other hand, the movable element (the light receiver) is protected from external media by the chamber. The

  In fact, the light receiver is suitable for movement in the near image focal plane of the lens or in a plane parallel to the near image focal plane.

  The servo control that can be used is within the normal capabilities of those skilled in the art. They can in particular apply the same principles as those implemented in the known concentrators. In the absence of solar radiation, or in the absence of sufficient radiation, the receiver remains temporarily stationary in the chamber and re-establishes for focused light when the radiation has recovered to a sufficient level. Can be arranged.

  In one possible embodiment, a flux meter is provided that is suitable for sending a signal received by the light receiver to a drive means to control the speed and direction of movement of the light receiver.

  For an optimal receiver position, i.e., receiving all concentrated rays, the center of the receiver is one of the focal planes of the near image in the range from + k to -k. Should be located inside the area acting on the side. The median k of the region satisfies the following relationship.

ここで、ｒは、この断面が円である場合、またはこの断面が円でない場合は前記受光器の前記セクションに内接する円の半径である場合、前記受光器の横軸断面の半径である。“前記受光器の中心”との表現は、前記最終像焦面に平行な直線を意味することが理解されるならば、前記円の中心を通る。
ｓｉｎ［Ａｔａｎ］はｓｉｎｕｓ［ａｒｃ ｔａｎｇｅｎｔ］を表している。
ｄは、前記レンズの光軸と前記レンズの端の間の距離であり、前記光軸を含む平面であり、前記チャンバの底面に垂直であり、前記最終像焦面に直角である。

Where r is the radius of the horizontal cross section of the receiver if the cross section is a circle, or if the cross section is not a circle, the radius of the circle inscribed in the section of the receiver. If it is understood that the expression “center of the light receiver” means a straight line parallel to the final image focal plane, it passes through the center of the circle.
sin [Atan] represents sinus [arc tangent].
d is the distance between the optical axis of the lens and the end of the lens, is a plane containing the optical axis, is perpendicular to the bottom surface of the chamber, and is perpendicular to the final image focal plane.

  However, if an acceptable result can be obtained economically acceptable, for example if performance loss is offset by greatly reducing the cost of the concentrator, the center of the receiver is in this optimum region. It is also possible to arrange them outside.

  The converging lens may take various forms provided to concentrate the sun rays along a straight line. Thus, the converging lens may be planoconvex, biconvex, or converging meniscus.

  Preferably, and not exclusively, the converging lens may be a Fresnel lens in that it reduces the lens footprint and weight. A Fresnel lens also has the advantage that it absorbs less light than other lenses.

  In the case of a plano-convex Fresnel lens, i.e. a lens having a plane and a serrated surface, the lenses are preferably aligned so that the plane faces the outside of the chamber.

  This orientation has the advantage of facing the surface of the lens that is most likely to trap dirt inside the chamber, and the flat and outer surfaces are clearly easy to clean. For the same reason, when the Fresnel lens is biconvex, that is, a lens having a smooth convex surface and a sawtooth surface, the lens preferably has its convex surface facing the outside of the chamber. Would be matched.

  In another embodiment, the lens may be a converging meniscus lens, that is, a lens having a convex surface and a concave surface. Such a lens would need to be matched so that its convex surface faces the outside of the chamber.

  The light receiver is advantageously a heat pipe coated with a material, the heat absorption coefficient of which is greater than the heat release coefficient.

  In a particular embodiment of the invention, more specifically for the purpose of a solar power plant, the heat pipe is included in the pipe under vacuum to limit the heat loss and takes the form of a plastic as possible. .

  The heat pipe is advantageously connected to an extraction exchanger provided with a heat transport fluid, such as hot water or other fluid, to heat the device or to make use of the heat obtained to produce solar cooling Is done.

  In another embodiment, the light receiver is an extraction exchanger provided with a heat transport fluid.

  In yet another embodiment, the light receiver may be a photovoltaic cell light receiver.

  In a preferred embodiment, the receiver can occupy two positions: a working position that receives a predetermined thermal energy and a retracting position that receives a lower heat energy than the working position, and the risk of overheating, e.g. heat If the carrier fluid is no longer circulating in the extraction exchanger, the retracting means can move the light receiver from its working position to its retracted position.

  The light receiver is connected to a Stirling engine, i.e. an engine that takes advantage of the temperature difference between a heat source and a cold source, which are specifically intended to generate electricity.

Preferably, the surface of the lens is treated to reduce its degradation capacity over time, the degradation being mainly outside on the dirt and / or inside on the deposition of metal particles ejected from the reflective surface. Happens at. Such a treatment consists of a non-stick surface treatment that increases wettability, obtained by application of a thin layer of a compound based on SiO _x (such as SiO ₂ ) and / or like a TiO ₂ type photocatalytic compound. It consists of a coating that makes it possible to reduce the deposition of different contaminants.

  It also provides protection against aging of the lens material and is obtained by depositing on the outer surface of the lens of a conventional anti-glare optical layer. Such anti-glare treatment has the advantage of reducing the reflection of the light beam by the lens, which receives a specific incidence.

  The same applies to the reflective walls of the chamber and is advantageously treated to reduce the resolution capacity over time.

  Considering reflective walls, as a variant, they are made of reflective panels that can be removed for cleaning purposes, replacing or complete the chamber with flat packing for moving or transport purposes.

  The present invention will be further understood by reading the following description with reference to the accompanying drawings.

FIG. 3 is a cutaway perspective view of an embodiment of a chamber according to the present invention. Fig. 4 illustrates various types of lenses that can be utilized by the present invention with identification of thickness e. Fig. 4 illustrates various types of lenses that can be utilized by the present invention with identification of thickness e. Fig. 4 illustrates various types of lenses that can be utilized by the present invention with identification of thickness e. FIG. 4 is a diagram of one embodiment of a chamber according to the present invention illustrating the effect of the effective distance b in the depth direction of the chamber. FIG. 4 is a diagram of one embodiment of a chamber according to the present invention illustrating the effect of the effective distance b in the depth direction of the chamber. FIG. 4 is a diagram of one embodiment of a chamber according to the present invention illustrating the effect of the effective distance b in the depth direction of the chamber. FIG. 2 is a diagram of an embodiment of a chamber according to the invention, represented by a cross section of a plane perpendicular to the overall direction of the lens, illustrating the path of solar rays along two different incidences. FIG. 2 is a diagram of an embodiment of a chamber according to the invention represented by a cross-section of a plane perpendicular to the overall direction of the lens and illustrating the path of the sun rays along two different incidents. The parameter k and the optimum position area of the receiver are illustrated. Fig. 5b is the largest scale diagram of the final image focal region of Fig. 5a. 1 illustrates one embodiment of a drive mechanism for the heat pipe.

  As seen in FIG. 1, in this embodiment of the invention, the chamber 1 is a right-angled planar hexahedron consisting of a linear converging lens 2, a back or bottom wall 3 and a front wall with side walls 4a to 4d. The side walls 4a to 4d of the chamber 1 and the inner surface of the bottom wall 3 are reflective and the other is covered with a reflective film or lined with a removable reflective wall.

  The side wall 4b includes a slot as shown in 5 in which the heat pipe 6 can slide in a plane parallel to the entire surface of the lens 2, and the heat pipe allows this sliding movement on the opposite side of the slot. Supported by appropriate means (not shown).

  The heat pipe 6 is covered with a material having a heat dispersion coefficient lower than its heat absorption coefficient in order to limit the loss as much as possible. Extraction converter 7, which is fed with liquid that is cold on 7a and warm on 7b, releases heat from the heat pipe for proper exploitation.

  The chamber 1 is extended by a housing 8 for the extraction exchanger 7 (the beginning of which is shown in FIG. 1 by a dotted line) and a drive mechanism (see FIG. 6) not shown in FIG. The housing 8 has similar right-angled sections like the chamber and can be connected close to them to avoid the ingress of rainwater and dust. In order to slow down the aging of the plastic pipes 9a and 9b, it can be advantageously made opaque (FIG. 6).

  The lens 2 of the chamber 1 is exposed to solar rays along an incident that varies with time, season, etc., and two such different incidents are illustrated by lines R and R '.

  Returning to the optical axis plane, FIG. 4a represents the chamber 1 without the heat pipe 6 or the extraction exchanger 7 for clarity of expression, the lens 2 comprising a plano-convex Fresnel lens 2, It can be seen that the plane faces the outside of the chamber. The thickness of the lens in the figure is likewise exaggerated for clarity. The lens 2 has an optical axis AA in which the focal length f is larger than the depth p of the chamber 1, and has an image focal plane PFI exceeding the bottom 3 of the chamber 1.

As described above, the depth p of the chamber must satisfy the following relationship:
p = 0.5 * (f + e + b)

  This relation is explained by referring to FIGS. 2a to 2c and 3a to 3b.

2a, 2b and 2c each form one of the chamber walls,
Plano-convex lens 2a, in this case a Fresnel lens.
A biconvex lens 2b and a meniscus lens 2c
And the beginning of the side walls 4a and 4c can be seen.

  In the case of the Fresnel lens 2a, the plane of the lens coincides with the plane FF passing through the adjacent ends of the side walls 4a to 4d, and the penetration thickness e is the most protruding portion of the plane FF and the lens in the chamber. The distance between the planes TT that is the tangential direction.

  In the case of the biconvex lens 2b, one of the convex surfaces of the lens protrudes outside the chamber 1, and the other convex surface protrudes toward the inside of the chamber. The penetration thickness e is a tangential direction of a median surface of the lens, that is, a plane that coincides with a plane FF that passes through the adjacent ends of the side walls 4a to 4d, and a most protruding portion of the lens inside the chamber. The distance between the planes TT.

  In the case of the meniscus lens 2c, neither part of the lens penetrates into the chamber (away from the fixed lens), so that the thickness e is greater or less than zero.

  As can be seen from FIGS. 3a and 3b, the lens has been designated 2a to 2c to indicate that it can be any one of the lens types 2a, 2b and 2c illustrated in FIGS. 2a to 2c. It is represented schematically in the form of a simple rectangle. The parameters required to determine the depth of the chamber are shown.

  3a and 3b, it can be seen that the lenses 2a to 2c have a distance that determines the image focal plane PFI, a thickness e and a focal length f.

  In the case of FIG. 3a, the distance that needs to be adjusted for the receiver, in other words, the heat pipe 6 in the embodiment of FIG. 1, and its support opposite to the slot 5, the lens, and therefore the Considering the thermal sensitivity of the lens material, an effective distance b1 is provided.

  Initially, for simplicity, it will be assumed that the receiver 6 is in the PFIR plane located at e + b1 from the plane FF, which is a specific case, as can be seen in light of FIGS. 5a and 5b. The bottom surface 3 of the chamber must likewise be equidistant from the PFIR plane and the PFI plane.

For b = _{b 1} (FIG. 3a), the distance between the PFIR and PFI is 2 * _{x 1.}

_{b = b 2, b 2>} b case ₁ (FIG. 3b), the distance between the PFIR and PFI is 2 * _{x 2.}

  The selection of b is within the skill of the artisan. That means that it depends on the footprint of the receiver 6 and is related to the material of the lens.

  As an example, in a 50 cm × 100 cm plano-convex Fresnel lens made of glass having a reflectance n = 1.5, a focal length f of 80 cm, a thickness e = 1.5, and an effective distance b = 15 cm, The depth p of the chamber 1 is equal to 0.5 (f + e + b) = 0.5 * (80 * 1.5 * 15) = 48.25 cm as a result of the following. Obviously, these values are given only to allow the reader to have a clear understanding of the principles of the invention. In fact, these values are other values and the depth of the chamber is even smaller with respect to the focal length.

  Returning to FIG. 4a, if there is no bottom surface of the chamber, the sun rays striking the lens 2 parallel to the ray R are concentrated on the first image focal plane in the image focal plane PFI. However, the reflective side walls, such as 4a, and the reflective bottom surface 3 of the chamber block the ray R and they are parallel to the image focal plane PFI and inside the chamber 1. Reflect them until they are focused on the image focus in the near image focal plane PFIR. In FIG. 4a, this final image focal plane is seen in the form of a cross section and hence dot I.

  FIG. 4b is similar to FIG. 4a, except that another direction of ray impact such as R 'is illustrated on the lens 2. FIG. As can be seen, after multiple reflections, these rays R ′ are concentrated on the final image focal plane which is also located in the plane PFIR, which is in cross section in FIG. It is therefore seen in the form of dot I ′.

  Thus, the final image focal planes of the ray R and the ray R ′ are located on two different lines, but are in the same plane PFIR, in order to represent it differently, the linear final image focal plane. Move in a translational manner in the plane PFIR according to the orbit of the sun.

  Considering the specific case, the heat pipe 6 located in the plane PFIR moves according to this translational movement of the linear final image focus. For this purpose, power means are provided to servo-control the movement of the heat pipe in the solar trajectory, more precisely in the ray trajectory concentrated towards the final image focus. This servo control takes into account the plane, season, time, etc. on which the chamber is shown.

  As indicated above, the heat pipe is further exposed to retraction means applied to avoid heating, if necessary, outside its effective position, in order to move it. For this purpose, the pull-in means moves the heat pipe from an effective position that receives predetermined heat energy to a pull-in position that receives energy lower than the heat energy received from the effective position.

  As can be seen from the example shown above, the present invention significantly reduces the distance required between the lens and the heat pipe. Without the present invention, in a given example, this distance is fe = 80-1.5 = 78.5 cm, which is only 48.25 cm with respect to the present invention and in the example considered above.

  Referring to FIG. 5 a, the chamber 1 is shown with a lens 2 and its bottom surface 3. Similarly, seen in this figure is a light receiver 6a that can be represented in the form of an electrical device (see FIG. 5b) that is a circular cross section of radius r, but not necessarily circular. If the light receiver is not a circular cross section, an inscribed circle is considered in the non-circular cross section. Similarly, what is identified in this figure is the distance d used to calculate the value k.

R ₁ and R ₂ indicate the sun rays that form the outer boundary of light rays that strike the lens 2 at zero incidence. The line bounded by R ₁ and R ₂ converges towards the plane PFI, but is blocked and reflected by the bottom surface 3 to converge with the rays concentrated towards the plane PFIR, which is said plane PFIR Intersect along the line seen at the intersection at I ″ corresponding to the final image focus. The concentrated rays delimit two intersecting surfaces having an angle α on either side of the final image focal plane I ″.

As long as these planes are tangent to the receiver (position 6a in FIGS. 5a and 5b), or as a secant to the receiver (position 6a in FIGS. 5a and 5b), the receiver is concentrated. Receives all rays. However, if the receiver is located between these planes rather than those planes that are secant or tangent (position 6c in FIG. 5d), a portion of the concentrated rays, i.e. the rays The portions between the planes of R ₁ and R ₂ and the tangents T ₁ and T ₂ of the light receiver 6c do not hit the light receiver.

In this way, as seen in FIG. 5b, with respect to the receiver for occupying the optimum position, it passes through the center of the receiver and the final image focus I '' (receiver at position 6a). The line parallel to the line C _a , the line C _{b to the} receiver at position 6b) should be located on either side of the plane PFIR, in the region E between + k and −k, where k is The following relationship is satisfied.

ここで、ｒ、ｄ、及びｆは、上で定義されたものであり、前記受光器の中心は最終像焦点Ｉ’’ （上で述べた特別な場合）に一致することが可能な受光器である。

Where r, d and f are as defined above, and the center of the receiver can coincide with the final image focus I ″ (the special case described above). It is.

Line _Cc is outside the region E, and the position of the receiver as shown at 6c, however, does not exceed the scope of the present invention. For example, if it is less costly to position the receiver at 6c than 6a or 6b, this position is acceptable even if the receiver does not have to receive all of the concentrated rays. sell.

  In fact, the positions 6a, 6b and 6c are equally on the other side of the plane PFIR.

  FIG. 5b is further illustrated with respect to the light receiver 6a at 6a ′, which is generally outside of the light beam concentrated by the light receiver (in this case, the plane inside the concentrated light beam and bounding to this light beam). The effective position (which is tangent to) and the retracted position are shown. The position 6c can be taken into account to form a retracted position of the light receiver 6a.

  Referring to FIG. 6, reference numerals E1 and E8 respectively designate the internal space of the chamber 1 and the internal space of the housing separated by a partition 4b slotted at 5. As shown in FIG. 2, the exchanger 7 is located there, having a supply of cryogenic fluid on the heat pipes 6 and 7a and a discharge of hot fluid on 7b. More specifically, this supply and this discharge take place in fluid communication within the exchanger 7 via the respective pipes 9a and 9b connected to the nozzles 10a and 10b, respectively. The plastic pipes 9a and 9b are used to allow the heat pipe 6 to be moved.

  In order to obtain this movement, the heat pipe 6 is connected to a rotating shaft of a gear 13 that meshes with a rack 14 via a collar 11 provided with forks 12a, 12b, and the gear 13 is itself connected by a motor 15. It is driven to rotate.

  A flux meter is schematically shown as 16 and allows the signal to be sent to the motor means to control the direction and speed of rotation of the gear 13.

  Apparently, the invention is not limited to the illustrated embodiments. Thus, the lens and the bottom surface of the chamber need not be perpendicular to the wall of the chamber and need not be parallel to each other. Instead of incorporating a heat pipe, the chamber can contain two configurations as described for the heat exchanger, extraction exchanger provided with a linear capacitive coating with a photovoltaic cell, the heat pipe. In addition, juxtaposing several lenses forming the “sub-chamber” plane, common components, especially well-aligned sub-chambers with a common drive mechanism, limits the amount of component material utilized It is possible to reduce the number of servo controls with respect to the movement of the receiver.

DESCRIPTION OF SYMBOLS 1 Chamber 2 Converging lens 3 Bottom wall 4a, 4b, 4c, 4d Side wall 5 Slot 6 Heat pipe 7 Extraction exchange 8 Housing R, R 'light beam

Claims (18)

A condenser lens (2; 2a; 2b; 2c) having an image focal plane (PFI) called the “first image focal point” that is concentrated along the focal length f and a straight line as a condenser; A solar concentrator of the type comprising: a ray of sunlight (R; R ′; R ₁ ; R ₂ ), wherein the lens receives light and the concentrated rays move with the sun's orbit,
The converging lens (2; 2a; 2b; 2c) has two pairs of side walls (4a, 4c, and 4b, 4d), a bottom wall (3), and a front wall (2; 2a) formed by the lens. 2b; 2c) and one of the walls of the chamber (1) defined by each of the sidewalls (4a, 4c and 4b, 4d) being parallel to each other, One pair (4a, 4c) is perpendicular to the other pair (4b, 4d),
The side and bottom walls (4a to d, 3) inside the chamber are reflective,
The depth p between the front wall (2; 2a; 2b; 2c) and the bottom wall (3) is smaller than the focal length f of the lens,
After multiple reflections, the light rays that are sufficiently reflected are symmetric to the first image focus corresponding to the bottom wall (3) and to the image focal plane (PFI) associated with the bottom wall. Belongs to the symmetrical “near image focal plane” (PFIR) itself and is focused on a line called “ final image focus” (I; I ′; I ″) located inside the chamber;
The concentrator is maintained within the concentrated light beam or at least at the secant position of the light beam by means of servo-controlling the movement of the light receiver (6; 6a; 6b; 6c) to the movement of the light beam. Solar collector, characterized in that it includes a movable movable receiver (6; 6a; 6b; 6c) . Concentrator according to claim 1, characterized in that the chamber (1) is a right-angled parallelepiped and the depth p of the chamber satisfies the following relational expression for this purpose:
p = 0.5 * (f + e + b)
Here, e is the penetration thickness of the lens (2; 2a; 2b; 2c) in the chamber (1), and b is the lens (2; 2a; 2b; 2c) and the near-image focal plane ( PFIR) or the effective operating distance . The center of the light receiver (6; 6a; 6b; 6c) is located inside a region that operates in a range (E) ranging from + k to -k on either side of the near-image focal plane (PFIR). The collector according to claim 1, wherein k, which is an average up to the region, satisfies the following expression.

r is the radius of the cross section of the horizontal axis of the light receiver when the cross section is circular, or when the cross section is not circular, the circle is inscribed in the cross section of the light receiver. If “center of” means a straight line (C _a ; C _b ; C _c ) parallel to the final image focus (I; I ′; I ″), this is the center of the circle. Passing through.
sin [Atan] represents sinus [arc tangent].
d is the distance between the optical axis (AA ′) of the lens and the end of the lens, and is in a plane including the optical axis (AA ′), and the bottom surface (3) of the chamber Perpendicular to the final image focus (I; I ′; I ″).   4. The concentrator according to claim 1, wherein the converging lens is a planoconvex (2; 2a), a biconvex (2b), or a converging meniscus (2c).   The concentrator according to any one of claims 1 to 4, wherein the converging lens is a Fresnel lens (2; 2a).   Concentrator according to claim 4, characterized in that the converging lens is a plano-convex Fresnel lens (2; 2a) whose plane is aligned so as to face the outside of the chamber (1).   5. The concentrator according to claim 4, wherein the converging lens is a biconvex Fresnel lens that is aligned so that its convex smooth surface faces the outside of the chamber (1).   8. The light receiver (6; 6a; 6b; 6c) is a heat pipe coated with a material, the heat absorption coefficient of which is greater than the thermal diffusion coefficient. Concentrator.   The concentrator of claim 8, wherein the heat pipe is in the form of a pipe contained in the pipe under vacuum.   10. Concentrator according to claim 8 or 9, characterized in that the light receiver (6; 6a; 6b; 6c) is connected to an extraction converter (7) to which a heat transport fluid is applied.   The concentrator according to any one of claims 1 to 7, wherein the light receiver is a photovoltaic cell light receiver.   8. The concentrator according to claim 1, wherein the light receiver (6; 6a; 6b; 6c) is an extraction exchanger provided with a heat transport fluid.   13. The receiver according to claim 1, characterized in that it can occupy two positions: an operating position (6a) for receiving a predetermined thermal energy and a retracting position for receiving thermal energy lower than the operating position. The concentrator as described in any one of Claims.   14. The light collector according to claim 1, wherein the light receiver (6; 6a; 6b; 6c) is connected to a Stirling engine. Said lens (2; 2a; 2b; 2c ) and / or reflection wall of the chamber; surface of (3 4a-4d) is to be processed in order to reduce the degradation ability of the materials over time 15. A concentrator according to any one of the preceding claims, characterized in that it is characterized in that   Concentrator according to any one of the preceding claims, characterized in that the outer surface (2; 2a; 2b; 2c) of the lens comprises an antiglare treatment.   Concentrator according to any one of the preceding claims, characterized in that the reflective wall (3, 4a-4d) is made of a removable reflective panel.   2. A luminous flux meter (16) suitable for sending a signal to a driving means received by the light receiver for controlling the speed and direction of movement of the light receiver (6). The collector as described in any one of thru | or 16.

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