MEMBRANELESS LAMINATOR GROUP AND RELATIVE METHOD FOR MAKING LAMINATED PANELS OF DIFFERENT SIZES, IN PARTICULAR PHOTOVOLTAIC PANELS

Abstract

Membraneless laminator group (10) for making laminated panels comprising: one sealed lamination chamber (11) comprising a heated support and abutment base (12) for at least one panel; a movable cover (13) for opening and closing the chamber (11); a heated rigid plane (15) movable inside the chamber between a raised position spaced from the panel and a lowered position it presses the panel; wherein the surface of the plane (15) facing the panel is equipped with a thermal cover arranged loosely between the plane and the panel. When the plane (15) is in the raised position, the thermal cover engages the panel so as to transfer heat without acting by compression. When the plane is in the lowered position the thermal cover is in compressed configuration so that the compression is transferred against the panel and possible local thickness variations of the panel are compensated.

Claims

1. Membraneless laminator group (10) for making laminated panels, in particular photovoltaic panels, comprising at least one sealed lamination chamber (11) fed in succession by at least one multi-layer panel (17) and by a pump unit (30) for the selective evacuation of the air present in said lamination chamber (11); said lamination chamber (11) comprising a support and abutment base, (12), electrically heated, for said at least one multi-layer panel (17); a movable cover (13) for opening and closing said lamination chamber (11); means for the selective feeding (14) of said at least one multi-layer panel (17) into said lamination chamber (11); an electrically heated rigid plane (15) movable inside said chamber between a raised position spaced from said at least one multi-layer panel (17) and a lowered position wherein it acts in compression against said at least one multi-layer panel (17); means for controlling the motion of said movable rigid plane (15), characterized in that it comprises a thermal cover (52) loosely associated with the surface of said movable rigid plane (15) facing said at least one multi-layer panel (17), so that before said movable rigid plane (15) reaches said lowered position said thermal cover (52) contacts, at least partially, said at least one multi-layer panel (17) so as to transfer heat without acting by compression.

2. Group according to claim 1 characterized in that said thermal cover (52) is at least partially deformable so that, when said movable rigid plane (15) is in said lowered position, said thermal cover (52) can on one side transfer compression against said at least one multi-layer panel (17) and on the other side absorb and compensate for possible local thickness variations of said at least one multi-layer panel (17) and prevent, therefore, its breakage during the compression step.

3. Group according to claim 2 characterized in that said thermal cover (52) is of the multilayer type comprising an outer layer (50) made of plastic material which is high temperature resistant and has high non-stick properties and at least an inner silicon layer (51).

4. Group according to claim 3 characterized in that said outer layer (50) of said thermal cover (52) is made as a Teflon tape laterally constrained to said surface of said movable rigid plane (15) facing said at least one multi-layer panel (17) only laterally so as to obtain a loose cavity when said rigid plane (15) is in said raised position.

5. Group according to claim 1 characterized in that it comprises at least two inner silicon layers; heating means interposed between said inner silicon layers being provided.

6. Group according to claim 1 characterized in that said means for controlling the motion of said movable rigid plane (15) comprise a plurality of pistons (18) acting mechanically on said rigid plane (15) to control the motion thereof and to impart a controlled compression to said at least one multi-layer panel (17).

7. Group according to claim 6 characterized in that said pistons (18) are housed above said movable cover (13) and connected to said rigid plane (15) through suitable holes (19).

8. Group according to claim 1 characterized in that it comprises at least one post-polymerization chamber (22) downstream of said lamination chamber (11), said at least one post-polymerization chamber (22) being of the heated type and subjected to atmospheric pressure.

9. Group according to claim 1, wherein the base (12) and the movable cover (13) of the laminator group (10) each have respective cavities that act as vacuum tanks, at least one additional pump for producing a vacuum, preferably operating continuously, being connected to the cavities of the movable cover (13) through at least one flexible pipe to allow the movement of the latter, the additional pump also being connected to the cavities of the base (12) through at least one rigid pipe.

10. Group according to claim 9, wherein the sum of the volumes of the cavities of the movable cover (13) and of the base (12) and the volume of the lamination chamber (11) is preferably about 5/1.

11. Method for making laminated panels, in particular photovoltaic panels, through a group comprising the steps of: a) feeding at least one multi-layer panel (17) to a lamination chamber of the type with a rigid movable plane (15); b) evacuating the air from said chamber to make the vacuum; c) heating said multi-layer panel (17); d) pressing said at least one multi-layer panel (17) through said rigid movable plane (15); wherein the surface of said rigid movable plane (15) facing said at least one multi-layer panel is loosely associated with a thermal cover (52) that is at least partially deformable so that: said step c) of heating said multi-layer panel (17) comprises: the step of bringing said thermal cover (52) in at least partial contact with said at least one multi-layer panel (17) even before said rigid movable plane (15) reaches said lowered position so as to transfer heat to the multi-layer panel (17) without acting by compression; and, thereafter, the step of bringing the rigid movable plane (15) into contact with the multi-layer panel (17) so as to act on the latter only with the weight of the rigid movable plane (15) to allow the transfer of heat from the latter to the multi-layer panel (17); step d) of pressing said at least one multi-layer panel (17) that takes place with said thermal cover (52) in a compressed configuration, so that on one side compression is transmitted against said at least one multi-layer panel (17) and on the other side possible local thickness variations of said at least one multi-layer panel (17) are compensated and it is thus prevented from breaking during the compression step.

12. Method according to claim 11 also comprising the step e) of arranging said multi-layer panel (17) directly from said lamination chamber (11) to a post-polymerization chamber (22) of the heated type and subjected to atmospheric pressure.

Description

[0103] The characteristics and advantages of a laminator group according to the present invention will become clearer from the following description, given as an example and not for limiting purposes, referring to the attached schematic drawings, in which:

[0104] FIGS. 1-5 show an embodiment of the invention;

[0105] FIG. 6 shows the pumping system;

[0106] FIG. 7 shows the rigid plane exploded according to the present invention; and

[0107] FIGS. 8 and 9 show diagrams of the progression of the temperature measured in three points of the panel.

[0108] With reference to the figures, a laminator group according to the present invention is shown with 10.

[0109] Such a laminator group 10 is of the membrane-less type and comprises, in its most reduced form, at least one sealed lamination chamber 11 fed in succession with at least one multi-layer panel 17 and a pump unit 30 for the selective evacuation of the air present in the lamination chamber 11.

[0110] The term at least one lamination chamber 11 is meant to indicate that the present invention aims to comprise both multi-plane embodiments, and mono-plane ones fed simultaneously with a plurality of panels.

[0111] The lamination chamber 11 comprises a base 12, of the known type, which acts as support and abutment for the panels, and a movable cover 13 for opening and closing the lamination chamber 11.

[0112] The means for opening and closing the chamber are of the known type.

[0113] The means for the selective feeding 14 of the panels are also of the known type and are schematized in the form of belts.

[0114] According to the invention, inside the lamination chamber 11 there is, as compression member, a rigid movable plane 15 instead of the silicone membrane currently used in the vast majority of groups of this type.

[0115] Such a rigid movable plane 15, preferably made of aluminum, is movable between a raised position spaced from the panels and a lowered position in which it acts in compression against them.

[0116] Of course, means for controlling the motion of the rigid movable plane 15 and means for heating the lamination chamber 11 or the multi-layer panel 17 contained in it are provided.

[0117] Specifically, the first innovative characteristic of the invention was that of comprising the heating means, for example electrical resistances or equivalent 40, embedded inside said rigid movable plane 15.

[0118] In order to avoid the classic problems of the rigid plane, highlighted earlier with reference to the presence of pointed projections on the upper face of the panel, the surface of the rigid movable plane 15 facing the multi-layer panel 17 is loosely associated with a soft thermal cover 52, i.e. that is at least partially deformable, so that: [0119] when the rigid movable plane 15 is in position of maximum lift it does not affect the de-aeration step; [0120] even before the rigid movable plane 15 reaches the lowered position, the thermal cover 52 is in contact, at least partially, with the multi-layer panel 17 so as to transfer heat to the latter without acting by compression; [0121] when the rigid plane is in lowered position acting on the panel only with its own weight so as to transfer heat faster since the rigid plane is electrically heated;when the rigid movable plane 15 is in lowered position and pressed against the panel, the thermal cover 52 is in compressed configuration so that on one side it transmits the compression against the multi-layer panel 17 and on the other side it compensates possible local thickness variations of the multi-layer panel 17 preventing it from breaking.

[0122] In FIGS. 3 and 7, such a thermal cover 52 is visible in schematized form.

[0123] Preferably, the thermal cover 52 is of the multi-layer type comprising an outer layer 50 made in the form of a mat or belt made of Teflon or plastic material resistant to high temperatures (up to 300 C.) with high non-stick properties and at least one inner silicone layer 51.

[0124] Again preferably, the outer layer 50 of the thermal cover 52 is constrained to the surface of the rigid movable plane 15 facing the panel only laterally or perimetrically so as to make a loose cavity when the rigid movable plane 15 is in raised position.

[0125] In such an embodiment, advantageously, between the silicone layers 51 it is possible to arrange heating means, such as electrical resistances 53 for example as alternatives or in addition to those embedded in the rigid movable plane 15.

[0126] FIGS. 4 and 7 indeed show how the rigid movable plane 15 is formed from two metal sheets 41, 42 inside which the electrical resistances 40 are housed.

[0127] Advantageously, in order to provide greater specific power and compensate for the higher dissipations of heat on the edges of the multi-layer panel 17 in formation, the laminator group 10 is equipped with suitable heating electrical resistances (not represented in the attached figures) or similar localized heating devices divided into independently activatable areas inside the rigid movable plane 15.

[0128] In particular, the aforementioned heating electrical resistances or the alternative heating devices identify, in the lamination chamber 11, distinct heating areas, like for example the central area, the perimeter bands and the corner areas.

[0129] On the upper metal sheet 41 of the rigid movable plane 15 it is possible to see the connection seats with the relative mechanical movement means.

[0130] In this way, and thanks to the concurrent effect of the thermal cover the aforementioned butterfly curvature is avoided without having to use lifting feet of the panel that, once it has entered inside the mold, would come into contact with the heated lower plane. For the composition of the layers of the photovoltaic multi-layer panel 17 reference should be made to the initial part of the present application.

[0131] The means for controlling the motion of the rigid movable plane 15 are of the mechanical type.

[0132] Of course, such means for controlling the motion of the rigid movable plane 15 can be independent from the heating means of the chamber. Although in the example shown the heating means are presented associated or embedded in the rigid plane, it is absolutely possible to use other heating methods.

[0133] For example, in the post-polymerization chambers 22 infrared lamps can be used, acting both from below and from above in the chamber.

[0134] As shown in FIGS. 1-5, the movement means comprise a plurality of pistons 18 acting mechanically on the rigid movable plane 15 to control the motion thereof and to impose a controlled compression on the panel 17. In such an embodiment the pistons 18 are housed above the movable cover 13 and connected to the rigid movable plane 15 through suitable holes 19.

[0135] Such an arrangement is extremely advantageous because, together with the absence of the lifting feet, it makes it possible to reduce the volume of air inside the chamber and, therefore, makes the relative emptying easier.

[0136] Advantageously, the pistons 18 are equipped with a control system, preferably programmable electronic, capable of differentiating individually or in predetermined groups and, therefore areas, the pressure to be exerted on the multi-layer panel 17 in formation. Preferably, the control system is set so as to differentiate the pressure exerted on the multi-layer panel 17 in formation, between a central area and a perimeter area, in particular circumscribing the central area.

[0137] Advantageously, the Applicant has devised a suitable pump unit with vacuum tanks connected to the chamber 11 for a first, almost instantaneous, evacuation, joined to a vane or screw pump in series with a Roots pump.

[0138] In FIG. 6 reference numeral 30 indicates the group where it is possible to see the flange 16 for connecting to a respective flange (not shown) of the chamber 11, the vacuum tanks 31, the vane or screw pump in series with a Roots pump 32, 33.

[0139] Moreover, instead of the outer vacuum tanks 31 volumes that are already present could be used for the same purpose for constructive reasons in the structure of the laminator thus further reducing the elements of the lamination group.

[0140] In particular, it is possible to exploit respective cavities defined in the structures of the base 12 and of the movable cover 13 of the laminator group 10 as vacuum tanks, with clear benefits in terms of compactness and total bulk of the group itself. An additional pump (not illustrated) for producing a vacuum, preferably operating continuously is connected to the cavities of the movable cover 13 through a flexible pipe to allow the vertical movement of the latter. The additional pump is also connected to the cavities of the base 12 through a rigid pipe. In this way, it is possible to ensure that the predetermined level of vacuum is reached in very quick time.

[0141] In accordance with such a solution, when the vacuum cycle starts, the cavities are placed in fluid communication with the main vacuum chamber, almost instantaneously reaching a depression equal to the ratio between the total volume of the aforementioned cavities and the volume of the lamination chamber.

[0142] The aforementioned ratio between the sum of the volumes of the cavities according to the movable cover 13 and to the base 12 and the volume of the lamination chamber is preferably about 5/1 for which reason in the main vacuum chamber a pressure of about 200 mbar is reached instantaneously.

[0143] Totally theoretically, the group could be made up of just the chamber 11 and the relative pumping and heating system.

[0144] Indeed, once the compression of the panel has been obtained, the subsequent post-polymerization steps could be carried out in the heated chamber 11 and open at atmospheric pressure.

[0145] However, as known, to increase production it is suitable to foresee at least one separate post-polymerization chamber 22 downstream of the lamination chamber 11.

[0146] In an innovative manner according to the invention, the post-polymerization chamber 22 is of the heated type and subjected to atmospheric pressure.

[0147] Unlike the prior art it foresees the operation of pressure also in such post-polymerization chambers.

[0148] It is extremely easy to understand the operation of the laminator group of the present invention described above in its structural components.

[0149] Indeed, the method for making laminated panels, in particular photovoltaic panels, through a group as described earlier comprises the steps of:

a) feeding at least one multi-layer panel 17 to a lamination chamber of the type having a rigid movable plane 15;
b) evacuating the air from the chamber to make the vacuum;
c) heating the multi-layer panel 17;
d) pressing the multi-layer panel 17 through the rigid movable plane 15.

[0150] Since, as described earlier, the surface of the rigid movable plane 15 facing the panel is loosely associated with the thermal cover 52, the step c) of heating the panel comprises the sub-step of bringing the thermal cover 52 into at least partial contact with the multi-layer panel 17 even before the rigid movable plane 15 reaches the lowered position so as to transfer heat to the multi-layer panel 17 without acting by compression. Again thanks to the presence of the thermal cover 52, the step d) of pressing said at least one multi-layer panel 17 takes place with the thermal cover 52 in compressed configuration so that, on one side it transfers the compression against the multi-layer panel and, on the other side, it compensates possible local thickness variations of the multi-layer panel 17 preventing it from breaking.

[0151] The subsequent post-polymerization step is carried out at atmospheric pressure feeding the multi-layer panel 17 directly from the lamination chamber 11 to a post-polymerization chamber 22 open at atmospheric pressure. The multi-layer panel 17 obtained with the laminator group 10 and the method described is recognizable because it is qualitatively better in terms of absence of the aforementioned defects.

[0152] It has thus been seen that a laminator group according to the present invention achieves the purposes highlighted earlier, also making it possible to make multi-layer panels of different shape and surfaces characteristics without requiring any specific setting as the type of multi-layer panel changes.

[0153] The laminator group of the present invention thus conceived can undergo numerous modifications and variants, all of which are covered by the same inventive concept; moreover, all of the details can be replaced by technically equivalent elements.