Injection box for a pultrusion system for producing fibre-reinforced plastic profiles, in particular plastic rods

Abstract

An injection box for a pultrusion system, the injection box comprising: a housing which has at least one fibre supply opening for supplying fibres, in particular glass fibres, carbon fibres or aramid fibres; an injection connection provided on the housing for injecting a liquid matrix material; and a delivery opening for delivering the fibres impregnated with the matrix material to a curing tool; wherein the output opening has a substantially circular cross-section.

Claims

1. An injection box (10) for a pultrusion system (12), wherein the injection box (10) comprises: a housing (18) with at least one fibre supply opening (18A) for supplying fibres (14); an injection connection (20) provided on the housing (18) for injecting a liquid matrix material (22); and a delivery opening (18B) for delivering the fibres (14) impregnated with the matrix material (22) to a curing tool (24); characterized in that the delivery opening (18B) has a substantially circular cross-section.

2. The injection box (10) for a pultrusion system (12) according to claim 1, wherein the delivery opening (18B) is provided directly on the housing (18) or on a calibration attachment which is able to be connected to the housing (18).

3. The injection box (10) according to claim 1, wherein the fibre supply opening (18A) also has a substantially circular cross-section.

4. The injection box (10) according to claim 3, wherein the diameter of the fibre supply opening (18A) is greater than the diameter of the delivery opening (18B).

5. The injection box (10) according to claim 4, wherein a cross-section of a cavity in the housing of the injection box (10) decreases substantially continuously from the fibre supply opening to the delivery opening (18B).

6. The injection box (10) according to claim 4, wherein a cross-section of a cavity in the housing of the injection box increases from the fibre supply opening (18A) up to an intermediate position in the housing, and decreases from the intermediate position to the delivery opening (18B).

7. The injection box (10) according to claim 6, wherein the intermediate position corresponds to the position of the injection connection (20).

8. The injection box (10) according to claim 1, wherein in the housing (18) of the injection box (10) a first plurality of cavities is provided substantially orthogonally to the direction of movement of the fibres (14).

9. The injection box (10) according to claim 1, wherein on the housing (18) a second plurality of injection connections (20) is provided.

10. The injection box (10) according to claim 9, wherein the first plurality is equal to the second plurality, wherein an injection connection (20) is assigned to each cavity.

11. A pultrusion system (12) for producing fibre-reinforced plastic rods (40), comprising the injection box (10) according to claim 1.

12. The pultrusion system (12) according to claim 11, further comprising a winding device (30), which is designed to wind winding fibres (38) and/or a winding band onto the fibres (14), impregnated with the matrix material (22), after their exit from the delivery opening (18B) of the injection box (10).

13. The pultrusion system (12) according to claim 12, wherein the winding device (30) is arranged in the direction of movement of the fibres (14) before the curing tool (24).

14. The pultrusion system (12) according to claim 12, wherein the winding device (30) is designed to receive at least one spool (36) with winding fibres (38), wherein the winding fibres (38) are provided as a twisted roving.

15. The pultrusion system (12) according to claim 12, wherein the winding fibres (38) and the fibres (14) impregnated with the matrix material (22) are made from the same fibre material.

16. The pultrusion system (12) according to claim 12, wherein the winding device (30) is designed to wind different types of winding fibres (38) adjacent to one another onto the fibres (14) impregnated with the matrix material (22) after their exit from the delivery opening (18B) of the injection box (10).

17. The pultrusion system (12) according to claim 11, wherein the winding device (30) comprises at least one rotary arm (34), which is able to be driven for rotation about a rotation axis which runs through the delivery opening (18B) of the injection box (10) and substantially parallel to the direction of movement (P) of the fibres (14) impregnated with the matrix material (22).

18. The pultrusion system (12) according to claim 11, further comprising a pre-forming unit (16) arranged in the direction of movement of the fibres (14) before the fibre supply opening (18A), which pre-forming unit is designed to apply liquid matrix material (22) onto the fibres (14) before their entry into the injection box (10).

19. The pultrusion system (12) according to claim 18, wherein the pre-forming unit (16) is designed to apply the liquid matrix material (22) in a pressureless or pressurized manner onto the fibres (14).

20. A fibre-reinforced plastic profile comprising plastic rod (40), wherein said plastic rod is produced by pultrusion using the pultrusion system (12) according to claim 11.

Description

[0031] Embodiments of the invention will be explained below as non-restrictive examples with the aid of the figures. There are shown herein:

[0032] FIG. 1 a conventional injection box as part of a pultrusion system, shown in a diagrammatic side view, of the prior art;

[0033] FIG. 2a-d diagrammatic cross-sectional views of four injection boxes according to the invention, with differently configured cavities;

[0034] FIG. 3 a diagrammatic top view onto an injection box according to the invention with four adjacent cavities and respectively assigned pre-forming units and calibration attachments;

[0035] FIG. 4 a diagrammatic side view of a pultrusion system according to the invention;

[0036] FIG. 5a a perspective view of a winding device of the pultrusion system according to the invention;

[0037] FIG. 5b a diagrammatic side view of the fibres, impregnated with the matrix material, after delivery from the delivery opening of the injection box in the region of the winding device;

[0038] FIG. 6a a cross-sectional view through a fibre-reinforced plastic profile according to the invention with fibres arranged centrally along a longitudinal centre axis of the plastic matrix for a use as reinforcement rod with incorporated optical communication line;

[0039] FIG. 6b a cross-sectional view through a fibre-reinforced plastic profile according to the invention with fibres distributed uniformly over a cross-section of the plastic matrix for a use as a reinforcement rod with incorporated electric heating; and

[0040] FIG. 6c a cross-sectional view through a fibre-reinforced plastic profile according to the invention with fibres distributed in substantially concentric rings over a cross-section of the plastic matrix for a use as a reinforcement rod with an incorporated coaxial cable.

[0041] FIG. 1 shows a conventional injection box 10 in a pultrusion system 12 of the prior art in a diagrammatic side view. From a frame, not illustrated on the left in the figure, with fibre rolls, rovings 14 of endless fibres are drawn via a pre-forming unit 16 into the injection box 10. The pre-forming unit 16 can be e.g. a plate with parallel rows of holes through which the rovings 14 run in order to be drawn from there in a parallel manner and at uniform predetermined distances through a fibre supply opening 18A into a housing 18 of the injection box 10.

[0042] The drawing function is exerted by a drawing unit, a so-called puller, which is likewise not illustrated on the right in the figure. The direction of movement of the fibre rovings 14 is from left to right in FIG. 1, as is indicated by arrows P.

[0043] On one side of the housing 18, an injection connection 20 is provided for injecting a liquid matrix material 22. In the interior of the housing 18 of the injection box 10, the rovings 14 are therefore acted upon pressure with the liquid matrix material 22 and are impregnated. The impregnated rovings 14 are drawn out from the injection box 10 through a delivery opening 18B on the right-hand side of the housing 18 in FIG. 1, and enter into a subsequent curing tool 24, which is generally a heat chamber. The cured fibre-reinforced plastic profiles leave the curing tool 24 on the right-hand side in FIG. 1, as is indicated by the further arrow P.

[0044] The fibre supply opening 18A and the delivery opening 18B are configured so as to be slit-shaped in such conventional injection boxes 10, as vertical slits in the case shown in the side view of FIG. 1. In numerous other applications of the prior art, the slits are oriented horizontally.

[0045] FIG. 2a-d show diagrammatic cross-sectional views of four injection boxes 10 according to the invention, with differently configured cavities 18C. In all the cases which are shown, both the fibre supply opening 18A arranged on the left in the figures, and also the delivery opening 18B arranged on the right have a substantially circular cross-section, wherein the diameter of the fibre supply opening 18A is greater than that of the delivery opening 18B.

[0046] In the embodiment of FIG. 2a according to the invention, the cavity 18C narrows in the interior of the injection box in the form of a continuous truncated cone from the fibre supply opening 18A to the delivery opening 18B.

[0047] In the embodiment of FIG. 2b according to the invention, the cavity 18C narrows in the interior of the injection box in the form of three truncated cones, arranged one behind the other, with different opening angles from the fibre supply opening 18A to the delivery opening 18B.

[0048] In the embodiment of FIG. 2c according to the invention, the cavity 18C narrows in the interior of the injection box 10 in the form of five truncated cones, arranged one behind the other, with differing opening angles from the fibre supply opening 18A to the delivery opening 18B.

[0049] In the embodiment of FIG. 2d according to the invention, a cross-section of the cavity 18C in the housing of the injection box 10 increases from the fibre supply opening 18A up to an intermediate position in the housing, and decreases from the intermediate position to the delivery opening 18B. The cavity 18C therefore has a pear-shaped appearance. Expediently, in this case the injection connection 20, which is not shown in the figures, is arranged at the height of the intermediate position on the housing 18, i.e. in the region of the greatest cross-section of the cavity 18C.

[0050] FIG. 3 shows a diagrammatic top view onto an injection box 10 according to the invention with four adjacent cavities 18C as in the embodiment shown in FIG. 2b. Before each cavity 18C a pre-forming unit 16 is arranged, behind each cavity 18C a respectively associated calibration attachment 18D is mounted on the injection box 10, at the rear downstream end of which the substantially circular delivery opening 18B is situated.

[0051] In the embodiment shown in FIG. 3, each cavity 18C is provided with its own injection connection 20. The four injection connections 20 are supplied through a shared injection box supply line 26 with liquid matrix material 22 from a matrix material tank.

[0052] From the same tank, not illustrated in the figure, matrix material 22 can also be directed via a pre-forming unit supply line 28 to the four pre-forming units 16, in order to drip down there onto the fibre rovings 14, before they are drawn into the injection box 10. In this way, the rovings 14 can be acted upon all around with liquid matrix material 22, before they are compressed in the respective cavity 18C of the injection box 10. Therefore, it is ensured that the rovings 14 are not only wetted by matrix material 22 on their exposed outer side, but over their entire circumference, which improves the complete as possible impregnating of the rovings 14 with matrix material 22.

[0053] In the embodiment shown in FIG. 3, the through-duct of each calibration attachment 18D, the cross-section of which corresponds to that of the delivery opening 18B, is illustrated to be considerably smaller than the cross-section at the rear downstream end of the cavity 18C. Each calibration attachment 18D can be exchanged for a different calibration attachment 18D with a different through-duct, for example with a through-duct, the cross-section of which corresponds to that at the rear downstream end of the cavity 18C, or an even larger through-duct. Hereby, reinforcement rods or other fibre-reinforced plastic profiles with different cross-sections can be produced.

[0054] FIG. 4 shows a diagrammatic side view of a pultrusion system 12 according to the invention, in which an injection box 10 according to the invention in accordance with the embodiment shown in FIG. 2a comes into use without an upstream pre-forming unit and without a calibration attachment.

[0055] In this pultrusion system 12 according to the invention, a winding device 30 is arranged between the delivery opening 18B, provided directly on the housing 18, of the injection box 10 and the curing tool 24. The winding device 30 is illustrated isolated in perspective in FIG. 5a. It comprises a drive unit 32, which drives a rotary arm 34 via a belt drive about a rotation axis which runs through the delivery opening 18B of the injection box 10 and substantially parallel to the direction of movement of the fibres 14 which are impregnated with the matrix material 22. At one end of the rotary arm 34 a spool 36 is mounted, on which a twisted roving 38 is wound.

[0056] While the fibres 14, impregnated with matrix material 22, are drawn by the puller out from the delivery opening 18B of the injection box 10 and through an opening in the rotary arm 34 in the region of its rotation axis, they are immediately subsequently wound by the winding device 30 with the twisted roving 38. In the diagrammatic illustration of FIG. 5b, the direction of movement of the fibres 14, impregnated with matrix material, is indicated by a straight arrow P from left to right, the winding direction being indicated by a curved arrow U. As this winding still takes place before the curing tool 24, the matrix material with which the fibres 14 are impregnated is still damp and penetrates into the twisted roving 38 which, as it were, becomes saturated with matrix material.

[0057] As shown in FIG. 4, the overall arrangement of fibres 14 impregnated with matrix material 22 and subsequently wound with the twisted roving 38 is drawn by the puller into the curing tool 24 and is cured there to a firm fibre-reinforced plastic profile 40.

[0058] By providing a further spool 36 on the rotary arm 34, for example at the other end of the rotary arm 34, two twisted rovings 38, for example of different materials, can be wound adjacent to one another onto the fibres 14 which are impregnated with matrix material 22. If applicable, the winding device can also have several rotary arms 34, in order to carry further spools 36 with twisted rovings 38 and/or with a winding band, which are to be wound adjacent to one another or on one another onto the fibres 14 which are impregnated with matrix material 22. In particular a continuous winding with a winding band which is electrically insulating or is shielding electromagnetic waves can be of importance when the produced fibre-reinforced plastic profile is provided with electrically conductive fibres 14 in its interior and/or with electrically conductive rovings 14 on its outer surface for signal transmission or current conduction.

[0059] Such possibilities for use of a fibre-reinforced plastic profile 40 according to the invention will be described below with the aid of FIGS. 6a-c, wherein in these figures, for reasons of clarity, the winding fibres or respectively the winding band are omitted.

[0060] FIG. 6a shows a cross-sectional view through a fibre-reinforced plastic profile 40 according to the invention for a use as a reinforcement rod with incorporated optical communication line.

[0061] The fibre-reinforced plastic profile 40 in the form of a rod comprises a cured plastic matrix of matrix material 22, into which a roving, i.e. a bundle of glass fibres 14 is embedded. In the embodiment which is shown, the glass fibres 14 run substantially centrally along a longitudinal centre axis of the plastic matrix. Such a central arrangement of the fibres 14 can be achieved without difficulty during production by pultrusion. A decentralized embedding of the glass fibres 14 into the plastic matrix parallel to the longitudinal centre axis of the plastic profile is, however, likewise possible, for example by displacement of the pre-forming unit 16 which is used. The illustrated fibre-reinforced plastic rod 40 can be used as a reinforcement rod in the erecting of buildings and, owing to the light-conducting characteristics of the glass fibres 14, permits at the same time a use as a data line for optical communication. In the case of incomplete curing in the curing tool 24, the fibre-reinforced plastic profile 40 illustrated in FIG. 6a can, however, also be used as a current line, for example an overhead line. In this case, a winding with an electrically insulating winding band by the winding device 30 is particularly advantageous.

[0062] FIG. 6b shows a cross-sectional view through another fibre-reinforced plastic rod 40 according to the invention, in which carbon fibres 14 are distributed uniformly over a cross-section of the plastic matrix. Owing to the electrical conductivity of the carbon fibres 14, this fibre-reinforced plastic profile can be used as a reinforcement rod in the erecting of buildings and, at the same time, can be used as electric heating.

[0063] Finally, FIG. 6c shows a cross-sectional view through a further fibre-reinforced plastic profile 40 according to the invention, in which fibres 14 are distributed in the form of substantially concentric rings over a cross-section of the plastic matrix. Such an arrangement is particularly advantageous for a use according to the invention as a coaxial cable, wherein the central conductor can alsosimilarly to the glass fibre roving of FIG. 6arun along the longitudinal centre axis.