FR2613273A1 - Method and plant for manufacturing isothermal sandwich panels - Google Patents

Abstract

This method consists in producing each sandwich panel by "moulding" between a lower bed 20a and an upper bed 20b, the lower bed being coated with a first resin layer, with a layer of insulating material and with a second resin layer, and the upper bed then being laid flat on this assembly, which is then hot pressed. Application to the manufacture of sandwich panels including a core produced from an insulating material, sandwiched between two facing walls made of laminated material, such as polyester.

Description

PROCESS AND PLANT FOR MANUFACTURE
ISOTHERMIC SANDWICH PANELS
The subject of the present invention is a method and an installation for the manufacture of isothermal panels comprising a core, made of an insulating material such as polyurethane, sandwiched between two facings in a laminated material such as polyester.

 Such panels can be produced individually in molds inside which is poured, on the fiberglass, the resin intended to form the facings.

In order to reduce manufacturing costs, it has been proposed by the
FR-70 29132, to make each facing by "molding" on a table.

In this process, the resin and possibly a textile reinforcement are placed on a table, and covered with the insulating material in plates and the assembly is then passed through an oven, in order to accelerate the polymerization and the bonding of the insulating plates with the polyester facing, by heating and applying pressure. In the oven, pressure is applied by means of rollers acting on the plates of insulating material, which leaves marks on them. Furthermore, this method allows only one facing face to be produced at a time and requires the recovery of the assembly for the production of the other facing face.

 By FR-73 17424, it was also proposed, in an installation similar to that of FR-70 29132, to continuously manufacture on a parallel track, a facing sheet, and to apply it, after turning over, against the upper face of the insulating material, so as to obtain the complete sandwich panel. Such a manufacturing process poses enormous production problems, in particular with regard to the inversion of the facing sheet and its connection to the insulating material.

 The object of the present invention is to remedy these drawbacks and to provide a method and a manufacturing installation which make it possible to avoid the drawbacks described above and which in particular allow the manufacture of a sandwich panel during the same manufacturing cycle, without the need for rework.

 To this end, the process which it relates to consists in producing each sandwich panel by "molding" between a lower marble and an upper marble, the lower marble being coated with a first layer of resin, with a layer of insulating material and of a second layer of resin and the upper marble then being laid flat on this assembly, which is then hot pressed.

 Preferably, to facilitate the release of the finished panels, each marble is previously coated with a release agent such as a wax or the like.

 In the case where it is desired that one of the facings or each of them is provided, upon demolding, with a finishing plaster, according to another characteristic of the invention, before the application operation of resin, each marble concerned is covered with a finishing coating such as a gelcoat.

 Finally, to improve the mechanical strength of the resin, according to yet another characteristic of the invention, before its application to a marble, the resin is mixed with chopped glass fiber.

 Furthermore, if necessary, the resin, whether or not provided with chopped glass fibers, is reinforced by a textile sheet, woven or not, made of glass fibers or not, deposited on the marble immediately after the application of the resin.

 The installation for the implementation of this process comprises two parallel paths intended for the circulation of the marbles which act as molds, the downstream end of the first corresponding to the upstream end of the second, a first way of preparing the marbles along which are arranged cleaning stations and preparation stations such as release agent application stations and finishing plaster for panel facing, and a second path on which the marbles flow in direction opposite to the first and along which are arranged at least two devices for applying resin optionally mixed with chopped glass fiber, a station for depositing isothermal plates, possibly equipped with inserts and assembly keys, located between the two aforementioned resin application devices, a tunnel oven located downstream of the second resin application station to ensure pressure polymerization of the resin in front constitute the facings of the panels, and finally a demoulding station located at the downstream end of the second track, while between the downstream ends of the first track and upstream of the second are provided transfer means intended to transfer, the first way to the second, one out of two of the marbles prepared and that other means of transfer by turning are provided, between these two ways, at a location located between the second resin application station and the tunnel furnace fitted the second way, and allowing the removal, upstream of the tunnel kiln, of each marble turned over on one of the marbles transferred without turning and already coated with the different layers which should constitute a panel.

 Advantageously, the polymerization tunnel oven is equipped with pressing means making it possible to press the returned upper marble in the direction of the unreturned lower marble. In this case, the tunnel oven can be constituted by a heating press.

 It is also possible to provide, if desired, upstream of each resin application device, a station for depositing a textile sheet, woven or not, made of glass fibers or the like.

 By this arrangement, all the marbles are prepared on the same production route and no take-back operation is necessary.

 In addition, as it is the assembly of the two upper marbles and of the different layers of a panel which is passed through the heating press, there is no longer any risk of marking or deterioration of the insulating core of the panel. .

Anyway, the invention will be well understood and other characteristics thereof will be highlighted with the aid of the description which follows with reference to the appended schematic drawing illustrating by way of nonlimiting example, a form of preferred embodiment of the manufacturing installation according to the invention
Figure 1 is a diagram of this installation;
Figures 2 to 10 are, on an enlarged scale, perspective views showing the detail of each of the stations of the installation
Figure 11 is a diagram of the device for moving the marbles at the press entry station.

 As shown in particular in FIG. 1, the installation for the manufacture of sandwich panels 16 according to the invention essentially consists of thirteen stations, namely twelve work stations (1 to 6 and 8 to 13) distributed along two parallel and equal length manufacturing tracks, on which circulate marbles 20 each of which constitutes a half-mold for a panel, and a station 7 for transfer, without turning, from one manufacturing track to another, the together constituting a kind of U.

 It is also planned at the level of the station 13, two other stations 14,15 offset laterally and whose role will be explained below.

 Each of these stations 1 to 13 consists essentially of a table Ia, I3a provided with means for advancing a marble 20 placed on it. These advancement means are of the type known per se and are represented in the drawing by lines transverse 19; they can be formed, for example, by rotating rollers.

 The marbles 20 are used for molding the laminated material facings of the sandwich panels 16 and are intended to be placed on each side of the insulating core of these as will be seen below.

 As can be seen in Figure 2, the first station 1 is a marble cleaning station 20; these are brought to the table 1a of this station by means of a turning device 21 formed by a plurality of rotating arms 22 provided with suction cups 24 and which will be described later.

 This turning device 21 is articulated on an axis 23 disposed midway between the tables la, 13a of the two extreme positions 1 and 13 of the installation, parallel to these, and by pivoting about its axis 23, takes a marble 20 on table 13a of workstation 13 and brings it by turning it over on table 1a of workstation 1.

 As shown in FIG. 2, the table 1a of the work station 1 is provided with transverse recesses 1b located in correspondence with the arms 22, so that the latter do not protrude relative to the surface of this table when they have just deposited a marble 20 and do not hinder the subsequent movement of this marble.

 At this station 1, the marble 20 which has just been deposited is advanced until it comes into contact with a limit stop Ic and it remains in place on the table la for the duration of the cleaning, which consists in removing and peeling off any trace of material which may remain from the previous mold release.

 Once the marble 20 has been cleaned, the limit stop lc is retracted and the marble 20 is engaged on the following work station 2. This station comprises, at its upstream end, in the direction of advance 90 of the marbles 20, a brushing device 27 consisting of a rotating brush extending transversely to the direction 90, and which perfects the cleaning of the marbles carried out at station 1.

 At this station 2, two operators 25 cover the marble 20 with a layer of wax or the like intended to facilitate demolding, and place bibs 26 thereon intended to delimit the dimensions of the panel which will be manufactured subsequently.

 The station 3, visible in FIG. 3, comprises, near its upstream end, a device 30 for applying a spray coating, this coating having to constitute the finishing layer of the external face of the panel facings which will be molded on this marble. This device 30 comprises in particular a gun 31 supplied with coating and animated, in a manner known per se, with a transverse movement back and forth relative to the table 3a of this station.

 This pistol 31 therefore covers the entire marble surface 20 as it progresses on the table 3a.

 Stations 4 and 5, visible in Figures 3 and 4, simply serve as transfer stations between station 3 and station 6, and allow, for example, to stop the plate 20 on one of stations 4 or 5 when the extension 5 or 6 is not free and is still occupied by another floor.

 At the upstream end of the table 6a of the station 6 is provided a roll 35 of woven glass fiber arranged transversely to the direction of advance 90.

 This roller 35 makes it possible to place fabric on the marble 20 which will constitute the reinforcement of a first facing of the sandwich panel.

 At the downstream end of each of the work stations 2, 3, 4, 5, 5 and 6 are provided, as for work station 1, limit stops 2c, 3c, 4c, 5c, 6c respectively which control the 'stopping a marble 20 on the corresponding table respectively 2a, 3a, 4a, 5a, 6a and which retracts when the marble must pass to the next station.

 It will be noted that only one marble 20 out of two, that is to say the so-called lower marbles 20a, pass from station 5 to station 6. The other marbles, which will be called upper marbles 20b, pass directly from station 5 to station 9 as we will see later.

 The station 7 is used to transfer a plate 20a from the first production line, which includes the stations there 6, to the second production line, which includes the stations 8 to 13.

 This station 7 comprises a table 7a which is mounted movable transversely, from a position 17a (on the left in FIG. 1) to a position 17b (on the right in FIG. 1) on rails 17 extending from the first track of manufacturing per second.

 Two end stops 17c are provided at the ends of these rails 17 to limit the transverse movement of the table 7a in one direction or the other.

 The table 7a also includes, at each of its ends, an end of travel stop respectively 7c, 7d for the plate 20 placed on it.

The operation of the transfer station 7 is as follows
After erasing the limit stop 6c, the plate 20a which was at station 6 is transferred to the table 7a of the station which is then at position 17a. When this plate 20a comes into abutment against the end of travel stop 7c, its transfer is stopped and the transfer of the table 7a from one production line to another is triggered.

 The table 7a therefore moves on the rails 17 until it arrives in its position 17b and in abutment against the end of travel stop 17c.

 At this time, the transfer of this marble 20a from table 7a to table Sa of the next station can be triggered.

 The limit stop 7d serves to indicate that a marble 20a has been completely transferred from the work station 7 to the work station 8 and makes it possible to control the movement of the table 7a from its position 17b to its position 17a, so that 'A new transfer of marble from station 6 to station 8 can be carried out.

 Station 8 includes two devices 40,41 for spreading the resin and cut glass fiber threads intended for the production of facings.

 Each device 40, 41 includes a gun 40a, 41a, capable of projecting the mixture of resin and fiberglass yarns onto the marble 20a placed on the table, which is mounted on this device so as to be movable transversely to the direction in advance (arrow 90).

 The transverse displacement of each gun 40a, 41a combined with the longitudinal displacement of the marbles 20a allows a uniform covering of the surface of these.

 Between the two devices 40, 41 is also provided a roll 45 of fiberglass fabric arranged transversely to the direction of advance.

 At station 8, each lower marble 20a is therefore first of all covered, by means of the device 40, with a first layer of polyester resin or the like mixed with strands cut from fiberglass and intended to constitute the first facing then , manually, of insulating plates 44 (cf. FIG. 4), which can be provided with means for joining together and, optionally, inserts, and with a second layer of polyester resin and glass fibers at means of the device 41, after possible interposition of a sheet of glass fibers by means of the roller 45, so as to constitute the second facing of the sandwich panel.

 It goes without saying that the speed of passage of each plate 20a at station 8 will be adjusted so as to allow these different operations.

 It will also be noted that the poses of glass fiber fabrics provided for in stations 6 and 8 can, if necessary, be eliminated (cf.

Figure 4), since the devices 40 and 41 make it possible to project strands of glass fibers simultaneously with the spraying of resin.

 The station 8 is also provided, like the stations 1 to 6, with a limit stop 8c.

 The station 9 is provided with a table 9a able to move vertically upwards and downwards.

 This table 9a can move between a maximum high position, determined by a high end stop 9b and in which it is at the same level as the table Sa of the previous station, and a low position determined by a low end stop 9b.

 This table 9a is also provided with an end of travel stop 9c at its downstream end in the direction of advance 90.

 Finally, there is provided in the central part of the table 9a a photoelectric cell 55 whose role will be explained later.

 As shown more particularly in Figure 5, midway between station 9 and station 5 is provided the pivot axis 63 of a turning device 61 similar to device 21 and having, like it, a plurality of arms 62, fitted with suction cups 64.

 This device 61 is intended to take from station 5 a lower marble 20b pending and to deposit it, from station 9, on a lower marble 20a already covered with two layers of resin and plates 44 of insulating material.

The transfer of the upper marble 20b from station 5 to station 9 is carried out as follows
When the lower plate 20a is in position on the table 9a of the station 9 (position detected by the end of travel stop 9c), the latter descends to its low end of travel stop 9b. Simultaneously, the turning device 61 grasps by its suction cups the upper marble 20b waiting at station 5 and by rotation of about 1800 brings it above the table 9, this device 61 stops when the underside of the marble 20b is horizontal.

 The table 9a then rises until the photoelectric cell 55 detects the meeting between the upper resin layer of the marble 20a and the lower face of the marble 20b.

 At this time, the suction at the suction cups 64 is cut and they therefore release the marble 20b which is then placed flat on the lower marble 20a covered with its different layers of resin and insulating plates.

 This arrangement makes it possible to obtain a uniform flat covering of the upper layer of resin by the upper marble 20b and therefore to avoid any creep thereof, which would occur if the upper marble 20b was placed on the lower marble 20a directly by the turning device 61, during the rotation thereof.

 Then, the turning device 61 pivots in the opposite direction so as to return to its initial position on the table 5 to be ready to receive another marble 20b, or to an intermediate position in the case where a marble 20a is still present on the Sa table, whether it is in station, or whether it is in transit on this one.

 The table 9a then rises to its upper stop 9b, so as to be at the same level as the other tables and to allow the panel during manufacture, sandwiched between the marbles 20a and 20b which it supports, to be able to go to the next station 10, which is constituted by a heating press, visible in FIGS. 5 and 3.

 The plates 10a of this press open by moving up the movable upper plate and the assembly constituted by the two marbles 20a, 20b, the resin layers and the insulating plates 44 is pushed inside of it. .

 Here, the drive system is constituted by a pusher 50 driven in the longitudinal direction by means of a chain system 51 and acting on the bottom plate 20a of the assembly (cf. FIG. 11).

 As emerges from the examination of FIGS. 5 and 6, as it enters the press, this assembly pushes, on the table lla of the next station II, that which was previously in the press. It is stopped when it reaches a limit stop 10c provided at the downstream end of the pesse 10. Within the press 10, the assembly is subjected to a pressure and to heating causing the resin layers to polymerize. deposited between the two marbles 20a and 20b and their connection with the insulating plates 44 placed between them, so as to obtain a sandwich panel 16.

 Of course, the metering of the resin and of the glass fibers as well as of the catalyst at the level of station 8 is carried out in such a way that the polymerization reaction takes place only when the assembly is in the press 10.

 The actuating cylinders (not visible in the drawing) of the movable upper plate of the press are arranged in lines parallel to the direction of movement of the assemblies constituted by the marbles 20a, 20b and their supply is controlled so that the cylinders arranged along the most central lines act before the others. This arrangement has the advantage of causing, with certainty, the elimination of any air bubble possibly trapped between a plate 20 and the panel 16 during manufacture.

 At the exit of the press 10, the assembly constituted by the marbles 20a, 20b and the sandwich panel 16 is transferred to the station 13 by passing over the various stations 11 and 12.

 These three stations 11, 12, 13 will each be fitted with a limit stop respectively llc, 12c and 13c at their downstream end, making it possible to stop the assembly each time it reaches the end of the station.

 At station 13, the various marbles 20a, 20b are removed and the finished sandwich panel 16 is unloaded.

 These various operations are carried out by means of a transporter device 70 extending between the stations 1,13,14 and 15 and by means of the turning device 21 described above and located between the stations 1 and 13.

 As shown in particular in FIGS. 6 and 7, the transfer device 70 consists of a gantry 71 extending between the stations 1 to 16 transversely to these and of a traveling crane 72 mounted movable on this gantry.

 The traveling crane 72 is itself provided with a gripping system consisting of a gripping plate 73 provided with suction cup 74. The gripping plate 73 is mounted on the traveling crane 72 so as to be movable in the vertical direction by means of arms articulated 75.

 End of travel stops respectively 81, 83, 84, 85 are provided on the gantry 71 at each station, respectively 1,13,14 and 15 to cause the ferry to stop at the level thereof when necessary.

 Upper and lower limit stops 86.87 respectively are also associated with the articulated arms 75.

The discharge cycle of the finished product is carried out as follows
The transporter 70 which, at the start of the cycle, bears against the stop 84 above the station 14, moves up to the top of the station 13 (stop 83). The gripping system 73,74 descends to the bottom stop 87 and takes, by suction from the suction cups 74, the upper marble 20b.

 The gripping system 73,74 then rises to its upper stop 86 and the traveling crane 72 moves to the stop 84. At this time, the traveling crane is located above the station 14, which is a station of waiting for the upper marbles. The gripping system descends again to the bottom stop 84 and deposits the upper marble 20b on the table of the station 14 (see Figure 6, arrow 100).

 The gripping system rises again and, by a new displacement of the overhead crane and of the gripping system similar to that described above, will take the finished sandwich panel 16 and deposit it at station 15 (Cf. arrow 91 in the figure 7).

 In the next step, the ferry returns to the top of station 13, picks up, in the same way as indicated above, the lower marble 20a, and transfers it to station 1 where it can be cleaned and reused for the manufacture of another sandwich panel 16 (see arrow 92 in FIG. 8).

 Then, the transporter returns to the top of station 14, takes up the top plate 20b which he had previously left on hold and puts it back on the table of station 13 (Cf. Arrow 93 in Figure 9).

 Finally, the upper marble 20b is gripped by the turning device 21 on the table 13a and is deposited by the latter, after turning, on the table 1a of the station 1 (see arrow 94 in FIG. 10).

 Thanks to this arrangement, one and the same face of each marble 20a, 20b is used each time.

 As is obvious, the present invention is not limited to the single embodiment described above by way of nonlimiting example, it embraces, on the contrary, all the embodiments using similar means or equivalent.

 Thus, for example, the transfer device by turning 21 could act inversely on the upper marbles 20b. Indeed, one could just as easily provide a rest position with its arms 22, carrying the suction cups 24 on their opposite face, erased in transverse recesses formed in the table 13.

Claims (17)

- CLAIMS  1- Process for manufacturing isothermal sandwich panels, characterized in that it consists in making each sandwich panel by "molding" between a lower marble (20a) and an upper marble (20b), the lower marble being coated with a first layer of resin, a layer of insulating material and a second layer of resin and the upper marble then being laid flat on this assembly, which is then hot pressed.  2- A method according to claim 1, characterized in that each marble (20) is previously coated with a release agent such as a wax or the like.  3- A method according to claim 1 or 2, characterized in that, in the case where it is desired that one of the facings of the panel (16) or each of them is provided, upon demolding, a coating finishing, before the resin application operation, each marble (20) concerned is covered with a finishing coating such as a gelcoat.  4- Method according to any one of the preceding claims, characterized in that, before its application to a marble (20), the resin is mixed with chopped glass fiber.  5- Method according to any one of the preceding claims, characterized in that a woven or non-woven textile sheet, made of glass fibers or the like, is deposited on the lower marble (20a) or the panel (16) during fabrication before application, respectively, of the first and second layers of resin forming the facings of this panel.  6- Manufacturing method according to any one of the preceding claims, characterized in that, for laying flat upper marble (20b! On the lower marble (20c), it consists in bringing the upper marble (20b) au- above the lower marble (20a), so that the face of this marble (20b) which has been prepared is found horizontally and opposite the face of the lower marble coated with the different layers and to move the 'towards each other the opposite faces of the lower marble (20a) and the upper marble (20b) until they come into contact with each other.  7- Installation for the implementation of the method according to any one of claims 1 to 4, characterized in that it comprises two parallel paths intended for the circulation of the marbles (20) which act as molds, the downstream end of the first corresponding to the upstream end of the second, a first route for preparing the marbles (20) along which are arranged stations (1,2,3,4,5,6) for cleaning and preparation such as bib application stations, release agent and finishing plaster for panel facing, and a second channel (7,8,9,10,11,12, 13) on which the marbles (20) run in opposite direction to the first and along which are arranged at least two resin application devices (40,41) possibly mixed with chopped fiberglass, a station for depositing isothermal plates (44 ), possibly fitted with inserts and assembly keys, located between the two aforementioned devices of applica tion of resin, a tunnel oven (10) located downstream of the second resin application station (41) to ensure the pressure polymerization of the resin which should constitute the panel facings, and finally a demoulding station (13) located at the downstream end of the second track, while between the downstream ends of the first track and upstream of the second are provided transfer means (7) intended to transfer, from the first track to the second, a (20a ) on two of the marbles (20) prepared and that other means of transfer by inversion (61) are provided, between these two paths, at a location located between the second resin application station (41) and the oven tunnel (10) equipping the second track and allowing the deposit, upstream of the tunnel oven (10), of each marble turned (20b) on one of the marbles (20a) transferred without turning and already coated with the different layers to constitute a panel (16).  8- Installation according to claim 7, characterized in that the polymerization tunnel oven (10) is equipped with pressing means making it possible to press the upturned upper marble (20b) in the direction of the unreturned lower marble (20a).  9- Installation according to claim 8, characterized in that the tunnel oven is constituted by a heating press (10).  10- Installation according to claim 9, characterized in that the actuating cylinders of the movable upper plate (lova) of the heating press (10) are arranged in lines parallel to the direction of movement of the assemblies formed by the marbles (20a , 20b) and their supply is controlled so that the cylinders arranged along the most central lines act before the others.  11- Installation according to any one of the preceding claims, characterized in that, upstream of each resin application device (40,41), there is provided a station (35,45) for depositing a textile sheet , woven or not, of glass fibers or the like.  12- Installation according to any one of claims 7 to II, characterized in that there is provided an end of travel stop respectively (Ic to 13c) at the downstream end of each of the tables (I to 13) in the direction (22) in advance of the marbles (20).  13- Installation according to claim 12, characterized in that a limit stop (7c, 7d) is provided at each end of the table (7a), a first stop (7c) used to detect the arrival at the end table of a marble (20) on the first production track (position 17a of table 7a) and the second stop (7d) used to detect the arrival at the end of the table of this marble (20) on the second track manufacturing (position 17b of table 7a).  14- Installation according to any one of claims 7 to 13, characterized in that, for laying flat an upper marble (20b) on a lower marble (20a), the upper marble (20b) is supported by a turning device (61) and brought about by rotation of about 180 °, above the lower marble (20a) and in that the table (9a) of the lower marble (20a) goes up to that it comes into contact with the underside of the upper marble (20b).  15- Installation according to claim 14, characterized in that after the establishment of the upper marble (20b) on the lower marble (20a), the table (9a) returns to the same level as the other work tables.  16- Installation according to one of claims 7 to 15, characterized in that there is provided between the stations (13,1) a transporter device (70) provided with a traveling crane (72) and a turning device ( 21), and in that these two devices cooperate to transfer the lower marble (20a) and the upper marble (20b), one after the other from the station (13) to the station (1), the upper marble (20b ) being returned using the device (21).  17- Installation according to claim 16, characterized in that the marble (20b) is put on hold on a station (14) by means of the transporter (70) and in that it is again transferred to the station (13) , then on the station (1) by inversion using the device (21).