FR3035813A1 - METHOD FOR MANUFACTURING CONSTRUCTIVE ELEMENTS BASED ON BAMBOO - Google Patents

Abstract

The present invention relates to a method of manufacturing a construction element comprising the following steps: - splicing of bamboo rods so as to obtain at least one continuous bamboo rod, - introduction of said continuous bamboo rod into a die (17) - transverse positioning of said bamboo rod relative to the die (17), - introduction of a binder between the bamboo rods, and / or between the bamboo rods and the die (17), so as to form a continuous beam, substantially of the section of that of the die (17), - sawing of said beam The present invention further relates to a specially designed installation for implementing the method according to the invention.

Description

The present invention relates to a continuous process for manufacturing bamboo-based construction elements.

In a previous patent application, No. FR 9669188, the applicant describes a constructive building construction element, based on bamboo rods and binder. Such a constructive element makes it possible, in particular, to build lightweight, insulating buildings and from a rapidly renewable raw material.

The manual manufacture of such constructive elements is a long and difficult implementation. Said application proposes a method of manufacturing such a constructive element by coextrusion and sawing. However, the Applicant has found that the implementation of such a process poses great problems, especially because the bamboo stalks, as harvested, are not rectilinear tubes of constant diameter. Moreover, the distribution of bamboo rods and binder in the building element is very random, which does not allow to obtain reliable binding bamboo rods between them. Finally the appearance of the bricks obtained is not satisfactory, revealing bamboo stems, as well as gaps between the bamboo stems. The present invention aims to overcome at least some of these disadvantages. For this purpose it proposes a method of manufacturing a construction element comprising the following steps: abutment of bamboo rods so as to obtain at least one continuous bamboo rod, - introduction of said continuous bamboo rod into a die, - positioning transverse of said bamboo rod relative to the die, 3035813 2 - introduction of a binder between the bamboo rods, and / or between the bamboo rods and the die, so as to form a continuous beam, substantially of the section that of the die, - sawing of said beam 5 Thanks to these provisions, it becomes possible to manufacture building elements based bamboo rods by a continuous process, which allows to consider a reduction of the labor costs of ooor and / or improvement of production rates. By "transverse positioning of the rod" is meant a positioning in the transverse plane of the rod which advances in the longitudinal direction. Indeed, the rod, which advances in the longitudinal direction, must arrive in the die with a correct positioning in the transverse plane of the die, to allow the other rods in particular to take their respective place.

According to other features, said method may further comprise an external calibration step of bamboo stems before the abutting step, so that the continuous bamboo stems obtained are continuous calibrated bamboo stems, said calibration step comprising a step of measuring diameter and straightness, where appropriate a straightening step, a step of sawing, so as to separate the rods of different diameters, and a sorting step, so as to gather the rods of similar diameters ; such a complementary step makes it possible to have calibrated bamboo rods of similar diameter and acceptable straightness for the manufacture of constructive elements; the step of joining two bamboo rods may comprise an internal calibration step of the ends of said bamboo rods; two bamboo stems, a step of introducing a trunnion into one of the ends and a step of fitting the second bamboo stalk on the trunnion, thus forming the abutment; such arrangements allow a reliable and resistant abutment, by simple means, in the internal calibration step of the ends, can be added a surfacing step ends, to obtain a seal of better quality between two butted rods.

The present invention also relates to an installation for manufacturing a constructive element by coextrusion through a die. This installation is particular in that it comprises: a feeding module made of bamboo rods, a butting module configured capable of assembling end-to-end bamboo rods, so as to form continuous bamboo rods, a die, of internal section the section of the constructive element to be manufactured, a transverse positioning means, configured to position the bamboo rods transversely relative to the die, a binder introduction means between the rods at the level of the die, and between the rods and the die, means for propelling the rods and the constructive element downstream of the installation, 15 - a cutting module, configured to cut the construction element downstream of the Faculty. The term coextrusion is used here to describe the fact that bamboo stems and binder enter a die, and the constructive element comes out at the other end. This term does not imply any input pressure here as may be the case for coextrusions of plastics for example. Thanks to these provisions, it becomes possible to manufacture constructive elements by a continuous process, and thus reduce the labor-free times required, while improving the reliability and reproducibility of the constructive elements obtained.

According to other features, said transverse positioning means may comprise a perforated plate, each hole being configured to pass a continuous bamboo rod, constituting a simple and robust means of transverse positioning; such a solution makes it possible to guarantee the distribution of the rods in the transverse plane, as for example in the case illustrated in FIG. 2, three rods aligned on an upper line, three rods aligned on an intermediate line, and three rods aligned on a lower line; The transverse positioning of all these rods is thus guaranteed, said perforated plate may furthermore comprise apertures configured to introduce the binder between the rods at the level of the die, thus improving the distribution of the binder between the rods. binder introduction means may comprise at least one binder sheet, for example of bioplastic material, in particular based on bamboo waste, means for introducing said sheet into the die so as to position it on one side of the binder; the constructive element, and a heating means of said sheet at its entry into the die, so as to make it formable; such arrangements make it possible to obtain the presence of binder all around the construction element, and to give it a smooth and continuous appearance, said die may comprise a movable formwork, configured so as to accompany the construction element in training course in the die, thus allowing sufficient time for the binder to take, and drying sufficiently to maintain its own weight and that of the rods, said propulsion means may comprise a means of thrust at the level of the finger-jointing module , thus making it possible to avoid gripping the constructive element during drying, which could damage the surface thereof, said installation may furthermore comprise a selection line comprising a means for measuring the diameter and the straightness such as a camera, a laser or a probe, a straightening means, and a cutting means. The advantage of the present invention lies mainly in the fact that it becomes possible to manufacture bamboo rod construction elements by a continuous process, with a reliable binder distribution, and an improved exterior appearance. The present invention will be better understood on reading the following detailed description with reference to the appended figures, in which: FIG. 1 is a schematic view of a selection line according to the invention, FIG. perspective view of a coextrusion line according to a first embodiment of the invention; FIG. 3 is a top view of the coextrusion line of FIG. 2, with the addition of an option according to a second embodiment, FIG. 4 is a schematic view in sequence of a splicing module of the coextrusion line of FIG. Figure 5 is a top view of a coextrusion line according to a third embodiment. The bamboo stalks, as they can be harvested, are not rectilinear and have a variation in their diameter, as well as defects in straightness. They can be first dried, before being used in the form of what we will call raw bamboo stalks 1.

The raw bamboo rods 1 are introduced into a selection line 2 comprising a measuring means 3 of the diameter and straightness such as a camera, a laser or a probe, a straightening module 4, as well as a means cutter 5 such as a saw or a knife. The straightening module 4 may comprise a heating means 6 and / or a mechanical straightening means 7. In some cases, it may be sufficient to heat to obtain a straightening of the bamboo tube, in other cases it may be sufficient to mechanical straightening 7 may be necessary, combined or not with a heating, comprising for example two jaws intended to be positioned on either side of the bamboo tube at the level of its defect of rectitude, and to lean the against each other, so as to straighten the bamboo tube. In most cases, a combination of heating and mechanical straightening is provided. When the measuring means 3 detects a straightness defect exceeding a first predetermined threshold, the rod is cut just before and immediately after the fault. For example, an elbow exceeding 30 ° over a length of 20mm can be eliminated by cutting before and after the elbow; we get a drop of 20mm, corresponding to the elbow.

When the measuring means 3 detects a straightness error exceeding a second predetermined threshold, but not exceeding said first predetermined threshold, the straightening module 4 is actuated. The defect zone is then heated and / or dechlorinated, and behind the selection line is obtained a defect-free rod. The second threshold may for example be 1 °, and it can be considered then that a straightness defect smaller than 10 is acceptable. When the measuring means 3 detects a too large diameter variation, the rod is cut off. At the output of the selection line 2 there is obtained a piece of rod of the initial diameter, and a second piece of rod of a second diameter. The system can be configured to differentiate between a change in diameter, treated as indicated above, and a defect of the type of a node, with a very localized oversize, that can be missed, or that can be cut, using a knife around the stem as a cylindrical pencil. The trajectory of the knife is then adjustable according to the diameter of the rod. Any other means of removing the localized allowance may of course also be used. The rods at the exit of the selection line 2 are called calibrated bamboo rods 8, and arranged by bundles of rods of similar diameter. The lengths of these rods can be very different. Below a minimum length, for example 50 mm, the rods are thrown as waste, or reused as trunnions 15, see below, or crushed for transformation into bioplastics. Above a maximum length, the stems are cut, even in the absence of a straightness defect or a change of diameter. The maximum length will depend on the size of the downstream machine, or the size of a container, for transportation. It can be for example 6 meters, or 12 meters. For the same bundle, outer diameters between 20 and 25mm, between 25 and 30mm, between 30 and 35, between 35 and 40mm, between 40 and 45, and between 45 and 50mm may for example be provided respectively. Lower ranges and a higher number of bundle types can also be provided. The skilled person will make the necessary choices, depending on the needs of the downstream process. The selection module comprises, downstream of the cutting means 5, means for orienting the calibrated bamboo rod 8 which has just been cut to the bundle corresponding to its outer diameter class.

The coextrusion line 9 comprises a feed module 10 configured to supply the line with calibrated bamboo rods 8, from bundles of calibrated bamboo rods 8. If, for example, it is desired to manufacture construction elements comprising thirty-five rods. calibrated bamboo 8 diameter 20 to 25mm, it is necessary to configure the supply module 10 able to feed thirty rods in parallel. This involves in this case thirty feed tanks, each fed continuously. The coextrusion line 9 further comprises a butting module 11, configured capable of assembling end to end, thus abut, two calibrated bamboo rods 8 10 of similar diameter. This splicing module 11 comprises for each line of calibrated bamboo rods 8 (thirty in the example above), an internal calibration means 12 of calibrated bamboo rod ends 8, a trunnion feed means 13 , and an abutment means 14, by engaging a pin 15 in one end of each of the two rods to be abutted.

The pin 15 may be bamboo, and may be hollow. It can come for example from a calibrated bamboo rod of smaller diameter, and of length too small to be retained for the butting. The butting module 11, illustrated schematically and sequentially in more detail in FIG. 4, may for example be configured to detect the end 20 of a calibrated bamboo rod 8 engaged in the coextrusion line 9 (step A), perform the internal calibration of said end (step B), receive the module of feeding a new calibrated bamboo rod 8, performing the internal calibration of the downstream end of said calibrated bamboo rod 8 (step C), receiving a journal 15 of the journal feeding means 13, inserting said journal 15 into the upstream end of the downstream rod (step D), then fit the upstream rod on said pin 15 (step E) until the downstream rod and the upstream rod are touching. It can be provided glue the pin 15 to improve the strength of the assembly, and can be added a heating means, for example by microwave, to accelerate the drying of the glue. It is also possible, in addition to the internal calibration (steps B and C), to plan the end, in order to improve the abutment, for example by means of a radial knife 28 placed on the forest. used for internal calibration.

Robotic means, known to those skilled in the art, make it possible to carry out these operations automatically. It is also possible to perform the internal calibration of calibrated bamboo rod ends 8 at the level of the selection line 2. It is also possible to add an end-fitting module to the selection line 2, and thus to to abut several calibrated bamboo rods 8 so as to form calibrated bamboo rods 8 of identical length, for example 6 or 12 meters, according to for example the containers provided for their transport. It can then be provided that the bundles are automatically poured into feed tanks 10, each provided for a diameter class, for their abutment, then sawing to the expected length of 6 or 12 meters for example, and then stored in a bundle where are then stored bamboo rods calibrated 8 at a time of similar diameter, but also of constant length. Such an arrangement at the level of the selection line 2 not only makes it easier to transport the bundles, but also to dimension the butting of the splicing module 11 of the coextrusion line 9 in relation to a fixed length and no longer in relation to the smaller length of rod. It is also possible, at the level of the selection line 2, to prepare the ends of the rods, with an internal calibration at each end, or even with a pin 15 already engaged on one of the ends, to simplify the process at the level of the coextrusion line 9. Thus, the combination of the feed module 10 and the splicing module 11 makes it possible to have a plurality of continuous calibrated bamboo rods 8, that is to say that the splicing is done as and as a measure, for a continuous supply of the coextrusion module 16 disposed downstream. The coextrusion module 16 comprises a die 17, having the desired internal section as external section for the constructive elements to produce. The coextrusion module 16 comprises a transverse positioning means 18 for the calibrated bamboo rods 8. This transverse positioning means 18 may be, for example, a perforated plate 18 having a hole 19 for each line of calibrated bamboo rods 8, diameter slightly greater than the maximum diameter possible for the calibrated bamboo rods 8 taken into account, so as to allow said rods to pass through the hole 19, and to be positioned transversely by this hole 19. The transverse positioning means 18 can also be a vibrator, especially when one seeks to obtain a contiguous arrangement of the bamboo rods 8 calibrated relative to each other. Such a vibrator can replace the hole plate 18, or be added to it, in particular be located between the plate with holes 18 and the die 17. According to a particular embodiment of the invention shown in Figs. 2 and 3, the abutment modules 11 may be arranged on superimposed levels, for example vertically aligned. This facilitates the arrangement of the power modules 10 one above the other, for easy access to each line of continuous bamboo rods. The continuous bamboo rods are then directed to each of the transverse positions at the die inlet 17, by elastic deformation of the continuous bamboo rods. Drawing 15 of FIGS. 2 and 3 illustrates an angle of inclination, and therefore a deformation, very exaggerated, to facilitate the clarity of the drawing; in fact the splicing module 11 may be disposed several meters from the die 17, thus allowing deformation of the rods quite acceptable. Fitting modules 11 may also be arranged, contrary to what is shown in FIG. 3, as seen from above they are each positioned opposite the transverse position imposed in the die 17, so that there is only elastic deformation of continuous bamboo rods in the vertical plane. The coextrusion module 16 further comprises a binder supply means configured to introduce the binder into the die 17 so as to distribute it between the calibrated bamboo rods 8 and between said rods and the walls of the die. 17. Such a binder supply means may for example comprise binder holes 20 in the perforated plate 18, or in the die 17, in the vicinity of the transverse positioning means 18, and a binder pumping means 30. through these binder holes 20. The arrangements to provide for such a binder pumping means are well known to those skilled in the art, and do not require a more detailed description here.

The binder can be a cement or the like, a thermoplastic or thermosetting polymer, or a bioplastic, which can for example be generated from bamboo waste. According to an embodiment shown in FIG. 3, the binder feed means may also include feeding a sheet 21 a few millimeters thick on one of the sides 22 of the periphery of the die 17. The sheet 21 may be plastic or bioplastic . Thanks to a heating means, it becomes deformable, and can adapt its internal shape to the bamboo rods, and its external shape to the die 17. This ensures the presence of binder on an entire face of the element constructive, and a perfect visual appearance or in any case significantly improved. By arranging such sheets 21 around the entire periphery of the die 17, a construction element completely surrounded by a binder is thus obtained, which makes it possible to obtain a smooth and continuous appearance.

According to an embodiment not shown, the coextrusion line 9 may comprise a means of feeding a section of bamboo wool. For example for a section of constructive element of 20 x 30cm, one can foresee a central section of 5 x 10cm, in which there is no bamboo stem provided, but instead of the bamboo wool, coming for example a roll of bamboo wool, which unfolds as and when, and which is introduced into the die through the plate with holes 18, by an opening provided for this purpose in the plate with holes. This opening may for example be arranged in the center of the plate with holes 18, so that the section of bamboo wool is surrounded by bamboo rods. Bamboo wool can also be replaced by another material, such as another mineral wool such as glass wool or rock wool. The die 17 of FIG. 2 is shown rectangular section. However, the section of the die 17 may have a different shape, in particular with one or more ribs on one side and one or more grooves on the opposite side, so as to facilitate assembly of the bricks side by side, at the one above, the other, as for example that shown in the document FR2 969 188.

According to a particular embodiment of the invention illustrated in FIG. 5, the die 17 may comprise a movable formwork 23. For example, each of the faces of the die 17 may consist of a plurality of plates 23 constituting a movable formwork, for example of wood or steel, hinged together, their 5 allowing to advance continuously with the constructive element being manufactured, then to fold back along a return strand of a chain 24, so as to allow a continuous advance of the plates 23. Such an embodiment can be particularly suitable for fast cement type binder, requiring several minutes of setting, before keeping its shape without being maintained. A drying tunnel 25 may be provided at the outlet of the die 17, if the type of binder and the manufacturing parameters make it useful or even necessary. After the coextrusion module 16 is a cutting module 26, which can be of any type suitable for cutting the constituent materials of the constructive element. This may be for example a circular saw, a band saw, a water jet cutter, a laser cutter, etc. The cutting module 26 is disposed on a carriage 27, allowing it to accompany the construction element. during the cutting operation, then, once the cut is over, to return to its initial position, to be ready for the next cut. The lengths obtained can be several meters to form beams for example 6 meters long, but can also be much smaller, to form bricks, for example 30 cm long. The coextrusion line 9 which has just been described thus makes it possible to obtain continuous manufacture of constructive elements from calibrated bamboo rods 8 prepared upstream on one or more selection lines. When one wants to start the continuous manufacture of constructive elements, it is necessary to select the die 17 corresponding to the shape and the section of the constructive element, to select the bundles of bamboo rods calibrated 8 according to the configuration defined by a designer ( few large rods, or rather many finer rods), and adjust parameters at the cutting module 26 so as to obtain constructive elements of the desired length.

For example, it may be possible to implement the selection line 2 as close as possible to the bamboo production site, in particular in South-East Asia, and then transport the bundles; it is then possible to provide the bundles with a maximum length of the length of a container, in particular 6m or 12m. We can then plan to implement the coextrusion line 9 closer to construction sites, especially in Europe or North America. Indeed binders, whether based on cement or a plastic material, can be found everywhere, and it may be advantageous not to add the weight of the binder to the bamboo for transport.

10 NOMENCLATURE 1. raw bamboo rod 2. selection line 5 3. measuring module 4. straightening module 5. cutting module 6. heating medium 7. straightening means 10 8. calibrated bamboo rod 9. coextrusion line 10. feed module 11. butting module 12. internal calibration means 15. 13. journal feed means 14. butting means 15. journal 16. coextrusion module 17. die 20 18. lateral positioning means 19. holes 20. binder holes 21. sheet 22. die side 25 23. mobile formwork, plates 24. chain 25. drying module

Claims (10)

REVENDICATIONS1. A method of manufacturing a construction element comprising the following steps: - splicing of bamboo rods so as to obtain at least one continuous bamboo rod, introduction of said continuous bamboo rod into a die (17), transverse positioning of said rod of bamboo with respect to the die (17), introduction of a binder between the bamboo stems, and / or between the bamboo stems and the die (17), so as to form a continuous beam, substantially of the section of that of the die (17), - sawing said beam. 2. Method according to the preceding claim, comprising a step of external calibration of bamboo rods before the abutting step, so that the continuous bamboo rods obtained are calibrated bamboo rods (8) continuous, said calibration step comprising a step of measuring diameter and straightness, if necessary a straightening step, a step of sawing, so as to separate the rods of different diameters, and a sorting step, so as to gather the rods of similar diameters. 3. Method according to one of the preceding claims, wherein the step of joining two bamboo rods comprises an internal calibration step of the ends of said two bamboo rods, a step of introduction of a pin (15). in one end and a step of fitting the second bamboo rod on the trunnion (15), thus forming the abutment. 4. Installation for the manufacture of a constructive element by coextrusion through a die, characterized in that it comprises: - a feeding module (10) in bamboo rods, 3035813 16 a butting module (11) , configured capable of assembling bamboo rods end to end, so as to form continuous bamboo rods, a die (17), of internal section the section of the constructive element to be manufactured, a transverse positioning means (18). ), configured to position the bamboo rods transversely with respect to the die (17), a binder introduction means between the rods at the die (17), and between the rods and the die (17), a means for propelling the rods and the construction element downstream of the installation; - a cutting module (26) configured to cut the construction element downstream of the die (17). 5. Installation according to the preceding claim, wherein said transverse positioning means comprises a perforated plate (18), each hole (19) being configured to pass a continuous bamboo rod. 6. Installation according to the preceding claim, wherein said perforated plate (18) further comprises openings configured to introduce the binder between the rods at the die (17). 7. Installation according to one of claims 4 to 6, wherein said means for introducing binder comprises at least one sheet (21) of binder, for example of bioplastic material, means for introducing said sheet (21). ) in the die (17) so as to position it on a face of the constructive element, and a heating means of said sheet (21) at its input into the die (17), so as to make it formable . 25 8. Installation according to one of claims 4 to 7, wherein said die (17) comprises a formwork (23) movable, configured to accompany the constructive element being formed in the die (17). 9. Installation according to one of claims 4 to 8, wherein said propulsion means comprises a thrust means at the butting module 30 (11). 3035813 17 10. Installation according to one of claims 4 to 9, further comprising a selection line (2) comprising a means (3) for measuring the diameter and straightness, a straightening module (4), and a means cutting (5).