VACUUM APPARATUS AND METHOD

Abstract

Disclosed is a vacuum apparatus for applying a vacuum to a reinforcement lay-up during in composite manufacture, and a method of use. The vacuum apparatus comprises a vacuum port component (100) having body portion (102) defining a contact surface (104) and an internal cavity. A vacuum port (108) for connection to a vacuum pump is oriented away from the contact surface communicates with the internal cavity. The vacuum port component can be connected to vacuum component (200) body portion also defining a contact surface and an internal cavity (207), and further comprising a plurality of inlet apertures or slots (206) extending therethrough and in communication with the vacuum component internal cavity.

Claims

1. A vacuum apparatus for applying a vacuum to a reinforcement lay-up during in composite manufacture; comprising a vacuum port component having a vacuum port component body portion defining a contact surface and an internal cavity, the vacuum port component further comprising a vacuum port oriented away from the contact surface and in communication with the vacuum port component internal cavity; a vacuum component having a vacuum component body portion defining a contact surface and an internal cavity; wherein the vacuum component contact surface comprises a plurality of inlet apertures or one or more inlet slots extending therethrough and in communication with the vacuum component internal cavity; the vacuum port component and the vacuum component being connected or connectable to one another to place the respective internal cavities in fluid communication with one another and to provide a contiguous vacuum apparatus contact surface.

2. The vacuum apparatus of claim 1, wherein the vacuum port component contact surface comprises a plurality of inlet apertures or one or more inlet slots extending therethrough and in communication with the vacuum port component internal cavity.

3. The vacuum apparatus of claim 1, wherein each contact surface is generally planar, and the vacuum port component and the vacuum component are connectable such that the respective contact surfaces are coplanar.

4. The vacuum apparatus of claim 1, wherein the vacuum port component and the vacuum component are connectable via a connection arrangement, the connection arrangement having a channel therethrough, and by which the respective internal cavities are placed in fluid communication when the vacuum port component and the vacuum component are connected to one another.

5. The vacuum apparatus of claim 4, wherein each of the vacuum port component and the vacuum component may comprise a connector sub-arrangement, having one or more connectors, and being connectable to another connector sub-arrangement to form the connection arrangement.

6. The vacuum apparatus of claim 1, wherein the vacuum port and vacuum components are connectable to one another to provide a substantially gas-tight seal; or wherein the connection arrangement self-seals in use, due to thermal expansion and/or dimensional changes when a vacuum is applied.

7. (canceled)

8. (canceled)

9. The vacuum apparatus of claim 1, wherein vacuum port component body portion and/or the vacuum component body portion is elongate.

10. The vacuum apparatus of claim 1, at least one said contact surface comprises one or more additional material layer applied thereto.

11. The vacuum apparatus of claim 10, wherein the one or more additional material layers comprises a semi-permeable membrane.

12. (canceled)

13. The vacuum apparatus of claim 1, wherein the contact surface of the vacuum component comprises a plurality of apertures, and wherein the plurality of apertures is evenly distributed across the contact surface.

14. The vacuum apparatus of claim 1, wherein the contact surface of the vacuum component comprises a plurality of apertures, wherein the apertures have a number density that varies across the contact surface.

15. The vacuum apparatus of claim 1, comprising one or more flow adjusting inserts for insertion into the internal cavity of a said body portion or connector sub-arrangement.

16. The vacuum apparatus of claim 1, comprising: multiple connection arrangements and wherein the vacuum port component and/or the vacuum component comprises more than one connection sub-arrangement; more than one vacuum component; and/or more than one vacuum port component; and one or more further connecting pieces; each connecting piece placing the internal cavities of any two vacuum components or vacuum port components connected thereto in fluid communication with one another.

17. (canceled)

18. (canceled)

19. (canceled)

20. The vacuum apparatus of claim 16, in the form of a kit of parts.

21. The vacuum apparatus of claim 20, comprising: one or more two-way, three-way, and/or four-way vacuum port components, with connector sub-arrangements extending in two, three or four corresponding directions, each having channels which communicate with one another and with the vacuum port of the said vacuum port component; and/or one or more two-way, three-way, and/or four-way connecting pieces, with connector sub-arrangements extending in two, three or four corresponding directions, each having channels which communicate with one another; and/or one or more end caps, for blocking connector sub-arrangements not in use; and/or one or more flow adjusting inserts, for insertion in a said connector sub-arrangement or a said internal cavity.

22. (canceled)

23. (canceled)

24. A method of applying a vacuum to a reinforcement lay-up in a vacuum bag; the method comprising; providing a reinforcement lay-up on a mould; providing a vacuum apparatus according to claim 1; connecting the vacuum port component to the vacuum component to place the respective internal cavities in fluid communication with one another; placing the contact surfaces of the vacuum port component and the vacuum component against the reinforcement material; coupling the vacuum port of the vacuum apparatus to a vacuum system through an aperture in a vacuum bag; sealing the vacuum bag to the mould around the reinforcement lay-up; and applying a vacuum to the reinforcement lay-up using the vacuum system, via the plurality of inlet apertures, or the one or more slots.

25. The method of claim 24, comprising laying up multiple plies of a dry reinforcement material on the mould.

26. (canceled)

27. (canceled)

28. (canceled)

29. A method of making a composite article, comprising applying a vacuum to a reinforcement lay-up in a vacuum bag in accordance with the method of claim 1, and infusing the reinforcement lay-up with a matrix material, while applying a vacuum via the vacuum apparatus.

30. The method of claim 29, comprising removing excess matrix material from the reinforcement lay-up, using the vacuum apparatus.

31. The method of claim 29, comprising preventing resin from entering at least a part of the vacuum apparatus, using semi-permeable membrane material applied to one or more said contact surfaces.

32. (canceled)

Description

DESCRIPTION OF THE DRAWINGS

[0161] Example embodiments will now be described with reference to the following drawings in which:

[0162] FIG. 1 is a schematic cross sectional side view of a typical resin infusion set-up, for vacuum assisted through the thickness resin transfer;

[0163] FIGS. 2a and 2b show perspective top and underside views of a vacuum apparatus;

[0164] FIGS. 2c and 2d show perspective top and underside views of a vacuum port component of another vacuum apparatus, having connection sub-arrangements;

[0165] FIG. 2e shows a four-way connecting piece of the vacuum apparatus;

[0166] FIGS. 3a and 3b show perspective views of an elongate vacuum component of the vacuum apparatus;

[0167] FIGS. 4a and 4b show perspective close up views of alternative elongate vacuum component, viewed showing the contact surfaces upward;

[0168] FIG. 5 shows a perspective view of an end cap of the vacuum apparatus;

[0169] FIG. 6 shows a perspective view of a linear vacuum port component of the vacuum apparatus;

[0170] FIG. 7 shows a perspective view of a linear connecting piece of the vacuum apparatus;

[0171] FIG. 8 shows a perspective view of a portion of a reinforcement lay-up and a vacuum apparatus against the reinforcement lay-up;

[0172] FIG. 9 shows perspective top and underside views of an alternative linear connector;

[0173] FIG. 10 shows a perspective underside view of alternative linear vacuum port component;

[0174] FIG. 11 shows a perspective view of an alternative end cap;

[0175] FIGS. 12a and 12c shows portions of a further vacuum apparatus against an edge of a reinforcement lay-up;

[0176] FIG. 12b shows a cross sectional view through the apparatus of FIG. 12a;

[0177] FIG. 12d shows a corner (two way) vacuum port component of the vacuum apparatus of FIGS. 12a-12c;

[0178] FIGS. 13a and 13b show, respectively, a vacuum apparatus and the vacuum apparatus placed against a reinforcement lay-up;

[0179] FIG. 14 shows the contact surface of a vacuum component of vacuum apparatus, configured to selectively apply a vacuum;

[0180] FIGS. 15a-c show flow adjusting inserts for a vacuum apparatus; and

[0181] FIGS. 16a and 16b show cross sectional views of vacuum apparatus having alternative key formations.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS

[0182] FIGS. 2a and 2b show perspective top and bottom view of a vacuum apparatus 100 for applying a vacuum to a reinforcement lay-up, such as a dry carbon fibre fabric lay-up, during VARTM.

[0183] The vacuum apparatus, a vacuum port component 100, has a body 102 with a planar contact surface 104 for placement on the surface of a reinforcement lay-up. The contact surface has a plurality of inlet apertures 106 therethrough, which extend into an internal cavity within the body (not visible in FIGS. 2a and 2b). On the opposite side of the body, oriented away from the contact surface 104, is a vacuum port 108, which is also connected to the internal cavity. In alternative embodiments (not shown) the contact surface has one or more slots across and/or around the contact surface.

[0184] The vacuum port is shown (schematically) as having a neck portion configured to extend through an aperture in a vacuum bag in use, and to connect to a vacuum line or hose. Typically, a neck with barb connections would be used but friction fittings or press fit connectors are also possible.

[0185] The surface area of the contact surface 104 over which the apertures 106 are distributed is considerably larger than the footprint of a conventional nozzle of a vacuum connector (in the example shown the length and width being around five times as wide as a vacuum nozzle normally used with a vacuum port of similar size to port 108). This provides for more effective application of a vacuum to (and in some circumstances removal of excess resin from) a reinforcement lay-up. Not only is the vacuum pressure more broadly distributed, but in embodiments the contact surface 104 may extend over an area which might otherwise require the provision of more than one vacuum port.

[0186] Extending from the contact surface 104 are key formations 110

[0187] A semi-permeable membrane 107 is affixed to the contact surface 104. The semi-permeable membrane 107 and body portion 104 are shown in an “exploded view” in FIG. 2a, and the membrane is omitted from FIG. 2b for clarity. The membrane 107 is substantially the same size and configuration as the contact surface and so extends across the apertures 106. In use, the semi-permeable membrane allows passage of gas, for example during evacuation of a vacuum bag and/or gas displaced or evolved during infusion, but substantially prevents passage of matrix material. Thus, the semi-permeable membrane prevents ingress of the matrix material into the internal cavity.

[0188] A semi-permeable membrane may be applied to any contact surface disclosed herein having apertures or slots therein, for this purpose.

[0189] FIGS. 2c and 2d show a vacuum port component 100a which includes connector sub-arrangements in the form of connectors 112 for connection to further components to effectively extend the size of the contact surface presented by the vacuum apparatus, as described in further detail below. The connectors 112 are male connectors for insertion into corresponding female connectors. The male connectors 112 include channels 114 therethrough, which communicate with the internal cavity within the body portion 102a.

[0190] In the embodiment shown, two male connectors are shown extending in each direction from the body 102a. In alternative embodiments, female connectors (recesses or plugs) may be provided, or a connection arrangement comprising a single connector on each side may be used. Locating pins may also be provided as part the connector sub-arrangement, to assist in alignment of connected components.

[0191] The vacuum port component 100a is adapted for connection to one or more further vacuum components and part of vacuum apparatus (examples as described below) and to provide a common vacuum port 108a.

[0192] FIG. 2e shows a connecting piece 100b of the vacuum apparatus, which is analogous to the vacuum port component 100a, but lacks a vacuum port. The connecting piece 2e may be used to connect between vacuum components in a region of vacuum apparatus which does not require a port—thereby obviating the need for corresponding connection to a vacuum system.

[0193] The connecting piece 100b (FIG. 2e) is a 4-way connecting piece. Other arrangements such as 2-way (corner or straight), and 3-way (T-piece, triangular) and the like are also possible.

[0194] FIG. 3a shows a vacuum component 200 with an elongate body portion. The contact surface 204 (FIG. 3b) has an elongated slot 206 therethrough. The slot extends to an internal cavity 207 (also elongate, in this embodiment) extending along and within the body 202. The vacuum component (and indeed other parts of the vacuum apparatus) can be of a flexible material such as silicon rubber or similar so as to conform to the geometry of the reinforcement lay-up.

[0195] The portion of the cavity 207 at the end 209 of the body is adapted to receive a male connector (not shown) and is thus configured in this region to function as a female connector 213.

[0196] FIGS. 4a and 4b show views of the underside of alternative embodiments of elongate vacuum component 200a and 200b. The bodies of the vacuum components 200a and 200b each have two internal cavities 207a, 207b. These vacuum components 200a, 200b are thus configured to be coupled to a vacuum port component such as the vacuum port component 100a or the connecting piece 100b, shown in FIGS. 2c, 2d and 2e.

[0197] The vacuum apparatus 200a has a contact surface 204a has a plurality of apertures 206a therethrough, which communicate with the internal cavities 207a. The vacuum component 200b has an elongate slot 206b communicating with each respective elongate cavity 207b.

[0198] Elongate vacuum component body portions as disclosed herein may conveniently made by extrusion of a plastics material. In addition, in use they may be readily cut to a required length.

[0199] As discussed above the vacuum apparatus disclosed herein may be of modular construction, for example from a kit of standard components, such as those described with reference to FIGS. 5-7.

[0200] FIG. 5 shows an end cap 220. The end cap has a “blank” male connector 222 to plug in and couple to the end of the cavity 207 at the end 209 of the vacuum component body 202. The connector 222 lacks a central channel and so acts as a terminating piece for such modular vacuum apparatus.

[0201] FIG. 6 shows a “straight line” linear vacuum port component 300 having a body portion 302, and male connectors 310 on opposite sides of the body 302, each having channels 314 therethrough, communicating with each other and a central cavity (not visible). The body 302 also includes a vacuum port 308 oriented away from the contact surface, having a neck 309 with a barbed hose connector 316. The top of the body 318 in use functions as a flange has an annular channel 320 therein, extending around the neck 309, which receives an O-ring 322, for sealing against an inside of a vacuum bag in use, in a manner well known in the art.

[0202] The vacuum port component 300 is configured to be coupled to the ends of elongate vacuum components 202.

[0203] FIG. 7 shows a linear connecting piece 300a, which is analogous to the vacuum port component 300, but lacks a vacuum port.

[0204] It should be noted that in the embodiment shown, the component 300 and connecting piece 300a each have male connectors 310, 310a having slot plugs 311, 311a on their undersides for blocking the ends of the slots 206. Accordingly, the contact surfaces of these connectors 300, 300a are not provided with slots or inlet apertures. Such slots or apertures may optionally be present in alternative embodiments.

[0205] FIG. 8 shows a portion of an assembled modular vacuum apparatus 350, with a contiguous contact surface, formed from co-planar contact surfaces of its component parts against a reinforcement lay-up 401 (in the embodiment shown, running along the top of an elongate stringer mandrel, with a reinforcing web component embedded in the reinforcement lay-up). The apparatus 350 includes multiple elongate vacuum components 202, an end cap 220, a linear connecting piece 300a, and a linear vacuum port component 300.

[0206] By connecting the neck 309 of the port 308 to a vacuum system, via a vacuum line (not shown) within a vacuum bag, a vacuum may be applied to the lay-up 401 along the entire length of the stringer via a single vacuum port 308. The apparatus 350 replaces at least two further vacuum ports which would be required in a conventional VATRM setup and in addition more evenly and effectively applies the vacuum, preventing dryness in the areas between conventional extraction points that would have either wise be induced by areas of low pressure a phenomenon commonly referred to as “vacuum lock-off”. The risk of vacuum lock-of can be further reduced by the provision of semi-permeable membrane along the contact surface(s) as disclosed herein.

[0207] With reference to FIGS. 9 to 12 further components of a kit for assembling modular vacuum apparatus compatible with the 4-way connecting piece 100b and 4-way connecting vacuum port component 100a, and the corresponding elongate vacuum components 200a and 200b, described above with reference to FIGS. 2c-2e and 4a and 4b.

[0208] FIG. 9 shows perspective top and underside views of a linear connecting piece 400. The connecting piece has a body 402 with an array of inlet apertures 406 on a contact surface 404 thereof. The connecting piece 400 has a pair of male connectors 412 at each end, having channels 414 through to an internal cavity in the body 402, which can be plugged into the “female” ends of the channels 207a or 207b. The contact surface 404 also has key formations 410.

[0209] Whilst the connecting piece shown could also be considered to constitute a “vacuum component”, its principal function is to connect adjacent larger vacuum components and so in the context of the vacuum apparatus with which it is compatible, can be regarded as a connecting piece.

[0210] FIG. 10 shows a corresponding linear vacuum port component 400a, where features in common with those of the connecting piece 400 are provided with like reference numerals having a suffix “a”. The vacuum port component 400a further comprises a vacuum port 408a communicating with the internal cavity thereof.

[0211] FIG. 11 shows an end cap 420, with male connectors 422.

[0212] FIG. 12a shows a portion of a vacuum apparatus 500 with elongate vacuum component body portions 502, adapted to be placed against a clean edge of a reinforcement lay-up. As shown in the cross section of FIG. 12b, the vacuum components 502 have an internal cavity 507, and a contact surface 504 for placement against a clean edge 651 of a reinforcement lay up 650, perpendicular to the orientation of the plies. The edge 651 may need to be trimmed, in use. The edge 604 could be interfaced with a common permeable or semi-permeable additional material layer, as disclosed herein, for preventing ingress of resin, or providing a suitable surface finish and/or facilitating removal of the apparatus 500 after infusion.

[0213] The vacuum apparatus 500 includes corner connecting pieces 520, having male connectors 522 extending in this embodiment at right angles to one another (FIG. 12b), which can be coupled to corresponding elongate vacuum components 502. Corresponding linear connecting pieces are also contemplated.

[0214] FIG. 12c shows another portion of the vacuum apparatus 500, with a corner vacuum port component 540 shown connected to further vacuum components 502. The vacuum port component has a vacuum port 508 and orthogonal male connectors 542 (FIG. 12d). When the vacuum port component 540 connected to a body 502, the vacuum port 508 is oriented away from the contact surfaces 504, in this instance orthogonal thereto.

[0215] A complex reinforcement lay-up 650 is shown in FIG. 13a, which has been laid up on a tooling surface 660 over a series of metal stringer mandrels 670.

[0216] Ordinarily the reinforcement lay-up 650 would require at least two vacuum ports per stringer (i.e. 6 in total, in the example shown), each of which would require sealing against and though apertures in, a vacuum bag. Each vacuum port would also need to be connected to a vacuum system, which would necessarily therefore include a complex network of vacuum hoses extending to a vacuum pump.

[0217] FIG. 13b shows an assembled modular vacuum apparatus 500 for placement against the reinforcement lay-up 650 around its peripheral edges, and an assembled modular vacuum apparatus 600 for placement on the upper surfaces of the mandrels—as depicted in FIG. 13a. The apparatus 500 includes four elongate vacuum components 502, three corner connecting pieces 520 and a vacuum port component 540. The apparatus 600 includes thirteen lengths of the extruded vacuum components 200a, cut to appropriate lengths, interlinked by 4-way connecting pieces 100b. The terminal ends of the components 200a are capped by end caps 420. Centrally positioned in the apparatus 600 is a linear vacuum port component 400a.

[0218] It will be appreciated that the apparatus is likely in practice to be assembled in situ, with individual components, or groups of components being placed against the lay-up 650, before draping or positioning a vacuum bag (not shown) over the reinforcement lay-up and apparatuses 500, 600, with the vacuum ports 408, 508 extending through apertures in the bag, and sealed. Thus, the number of required vacuum port connections and vacuum lines is reduced from ten or more (including those required around the periphery), as in conventional vacuum bag setup, to just two vacuum ports.

[0219] Other configurations of vacuum apparatus are also possible. For example, the linear vacuum port component could be removed and a single, longer elongate body employed, with a 4-way vacuum port component 100b in place of a 4-way connecting piece 100a.

[0220] Modular apparatus such as vacuum apparatus 600, or indeed any vacuum apparatus described herein, may also be placed on generally contact surfaces of reinforcement lay-ups, such as for aircraft skins, and not only on ridges or edges as shown in FIG. 13.

[0221] Relatively complex vacuum apparatus, such as apparatus 600, which include a network of interconnected internal cavities, and having inlet slots or apertures extending over a relatively wide area of a reinforcement lay-up may benefit from some means for selectively adjusting flow through the inlet apertures and channels in some region(s) of the vacuum apparatus. Adjustment of flow may assist achieving complete infusion of all parts of the reinforcement material. Modifying the flow in this manner can be particularly beneficial for complex lay-ups such as shown in FIG. 13a and can reduce the amount of excess resin which needs to be extracted via the vacuum apparatus and ensure complete infusion of the reinforcement material by avoiding vacuum lock off phenomena.

[0222] Flow adjustment means may take the form of a variation of the number density of inlet apertures 706, as shown in FIG. 14. The number density of apertures could for example be tapered from a high density at one end or region of a contact surface 704, to a lower number density in another region.

[0223] FIGS. 15a-c show tubular flow adjusting inserts 800a, 800b and 800c, for insertion into the internal cavity, or female connector, of a vacuum apparatus. The outer diameter d of each insert forms an interference fit with the cavity or female connector, whereas the inner diameters i.sub.a, i.sub.b and i.sub.c vary to provide a desired degree of flow restriction downstream thereof (i.e. between the flow restrictor and the nearest vacuum port).

[0224] FIGS. 16a and 16b show cross sectional view of alternative key formations, extending from the contact surfaces 904, 904a of apparatuses 900, 900a. Key formations 910a take the form of a lip extending down from the contact surface 904a, running lengthwise along at least a part of the length of the vacuum apparatus 900a. Key formations 910 take the form of a cut-out extending into the contact surface 904, running lengthwise along at least a part of the length of the vacuum apparatus 900.

[0225] Whilst exemplary embodiments have been described herein, these should not be construed as limiting to the modifications and variations possible within the scope of the invention as disclosed herein and recited in the appended claims.