FIELD

[0001] The present invention relates to ducting formed at least partly of resin and fibre, and more particularly but not exclusively to such ducting configured for use in mines.

BACKGROUND

[0002] Significant quantities of ducting are employed in underground mines for the purposes of delivering to underground locations a flow of air.

[0003] Ducting is also provided to extract air from underground mine locations for the purposes of removing dangerous gases and dust.

[0004] Disadvantages of the abovementioned ducting including weight, cost and complexity of the construction.

[0005] The abovementioned ducting is difficult to install as it is reasonably heavy and may be very flexible making it difficult to handle. This problem is exacerbated since the ducting is usually secured to upper surfaces of mine cavities and tunnels

OBJECT

[0006] It is the object of the present invention to overcome or substantially ameliorate at least one of the above disadvantages.

SUMMARY

[0007] There is disclosed herein a duct including:

a tubular body formed of resin and spirally wound fibre, the body having a longitudinal axis surrounded by a longitudinally extending radially inner surface and a longitudinally extending radially outer surface; and at least one reinforcing rib adjacent and projecting from said inner surface or said outer surface, the rib having a longitudinal length, a transverse width and a depth, and wherein each rib is secured to the adjacent surface.

[0008] Preferably, each rib is formed of resin and fibre, the fibre running longitudinally of the rib.

[0009] Preferably, the rib has a major direction of extension longitudinally of the body. [0010] Preferably, each rib is generally parallel to said axis.

[001 1] In an alternative preferred form, each rib has a longitudinal and angular direction of extension so as to extend in a spiral manner spirally about said axis.

[0012] In one preferred form, each rib is fixed to said inner surface.

[0013] In an alternative preferred form, each rib is fixed to said outer surface.

[0014] Preferably, said rib is a first rib, and said duct includes a second rib, with the first rib being secured to said inner surface, and the second rib secured to said second surface.

[0015] Preferably, the first and second ribs are spirally wound about said axis so as to have opposite winding directions.

[0016] Preferably, said tubular body is a first tubular body, and said duct includes a second tubular body also formed of resin and carbon fibre with ribs located between the tubular bodies.

[0017] In a further preferred form, further reinforcing ribs are fixed to the second tubular body so that the second tubular body is located between a radially inner set of ribs and a radially outer set of ribs.

[0018] Preferably, said duct has a first longitudinal end and a second longitudinal end, with said first longitudinal end having a socket that is to receive the second longitudinal end of a like duct to provide for connection of the ducts with the socket to receive the second longitudinal end of the adjacent duct. [0019] Preferably, said duct further includes a layer at least substantially co-terminus with said inner and outer surfaces.

[0020] Preferably, said duct has a generally circular transverse cross-section. [0021] Preferably, said fibre is carbon fibre. η

[0022] In an alternative preferred form, said fibre is glass fibre.

[0023] In a still further alternative form, said fibre is a natural or synthetic fibre.

[0024] In yet a further preferred form, said fibre is ARAMID® fibre.

[0025] Preferably, said duct includes an outer most surface, and a handle secured to said outer most surface.

[0026] Preferably, said duct includes an insert located inwardly of said outer most surface and secured to the tubular body and to which the handle is secured.

BRIEF DESCRIPTION OF DRAWINGS

[0027] Preferred forms of the present invention will now be described by-way of example with reference to the accompanying drawings wherein:

[0028] Figure 1 is a schematic isometric view of a duct;

[0029] Figure 2 is a schematic sectioned elevation of a portion of the duct of Figure 1 sectioned along the line 2-2;

[0030] Figure 3 is an isometric view of a second duct; [0031] Figure 4 is a schematic isometric view of a third duct; [0032] Figure 5 is a schematic isometric view of a fourth duct; [0033] Figure 6 is a schematic isometric view of a fifth duct; [0034] Figure 7 is a schematic isometric view of a sixth duct; [0035] Figure 8 is a schematic isometric view of a seventh duct; [0036] Figure 9 is a schematic isometric view of a still further duct;

[0037] Figure 10 is a schematic sectioned end elevation of the duct of Figure 4 sectioned along the line 10-10;

[0038] Figure 11 is a schematic sectioned end elevation of a further duct;

[0039] Figure 12 is a schematic sectioned end elevation of a still further duct;

[0040] Figure 13 is a schematic isometric view of a duct of an alternative configuration.

[0041] Figure 14 is a schematic isometric view of a modification of a duct of Figure 9;

[0042] Figure 15 is a schematic isometric view of a further modification of the duct of Figure 9;

[0043] Figure 16 is a schematic isometric view of a modification of the ducts described with reference to Figures 1 to 15;

[0044] Figure 17 is a schematic sectioned side elevation of a modification of the previous ducts, this modification including a handle; and

[0045] Figure 18 is a schematic sectioned side elevation of a modification of the duct and handle of Figure 16.

DESCRIPTION OF EMBODIMENTS

[0046] In the accompanying drawings there is schematically depicted a duct 10. Preferably the duct 10 is designed to be used in a ventilation system in an underground mine. [0047] The duct 10 includes a tubular body 11 formed of carbon fibre and resin. Typically the body 11 would be formed about a mandrel, with the carbon fibre spirally wound around the mandrel and impregnated with resin. Once formed, the body 11 can then be removed from the mandrel.

[0048] The tubular body 1 1 has a radially outer longitudinally extending surface 12 and a radially inner longitudinally extending surface 13, and is preferably of a circular transverse cross-section. A 50mm wid ribbon of woven fibre may be wound so as to be applied to the surfaces 12 and 13.

[0049] Adjacent and fixed to the surface 12 so as to extend therefrom is a plurality of ribs 14, each rib having a longitudinal length extending substantially the entire longitudinal length of the body 11 , a depth 15 (perpendicular to the surface 12) and a width 16. In this embodiment, the ribs 14 are generally parallel and parallel to the longitudinal axis 17 of the body 1 1 , and arguably spaced about the axis 17. When the duct 10 is generally cylindrical, the depth 15 is substantially radial. Preferably, the depth 15 is 0.5mm to 10mm. Preferably, the width 16 is 5mm to 50mm.

[0050] Preferably, each of the ribs 14 is formed of carbon fibre impregnated with resin, and is secured to the surface 12 by the resin.

[0051] The abovementioned ribs 14 increase the bending resistance of the duct 10 about an axis generally transverse of the axis 17, while also inhibiting crushing of the duct 10.

[0052] In the embodiment of Figure 3, the rib or ribs 14 are spirally wound around the axis 17. If there is more than one rib 14, then the ribs 14 are parallel. Accordingly each rib 14 extends angularly about the axis 17 as well as longitudinally relative to the axis 17. Again, the ribs 14 aid in stiffening the duct 10.

[0053] In the embodiment of Figure 4, the ribs 14 including a first set of ribs 18 and a second set of ribs 19. The set 18 may consist of one or more ribs 18 wound about the axis 17. The ribs 18 are wound in a predetermined direction about the axis 17. The set of ribs 19 may include one or more ribs 19 and are wound in the opposite direction to the direction of each of the ribs 18. Accordingly the ribs 18 and 19 intersect. [0054] Both sets of ribs 18 and 19 are formed of carbon fibre and resin and are secured to the outer surface 12.

[0055] Each of the ribs 18 and 19 are spirally wound relative to the axis 17 so as to extend angularly about and longitudinally of the axis 17.

[0056] In the embodiment of Figure 5, the duct 10 is similar to the duct 10 of Figure 4, however a further tubular body 20 is formed over the ribs 18 and 19, the tubular body 20 being formed of wound carbon fibre impregnated with resin. Part of the duct 10 has been removed to expose the

[0057] Fixed to the outer surface 21 of the tubular body 20, is a further rib or ribs 22 wound about the axis 17 in a spiral manner. Accordingly the ribs 22 extend both longitudinally and angularly relative to the axis 17. The ribs 22 are preferably formed of resin impregnated carbon fibre ribbon.

[0058] The embodiment of Figure 6 is a modification of the embodiment of Figure 2. In this embodiment overlaying the ribs 14 is a further tubular body 23. The tubular body 23 is formed of resin impregnated carbon fibre wound about the axis 17. Accordingly the tubular body 23 is also fixed to the ribs 14. In Figure 6, part of the ribs have been removed to expose the surface 12 and part of the tubular body 23 has been removed to expose the ribs 14.

[0059] The embodiment of Figure 7 is a modification of the embodiment of Figure 4. In this embodiment, the sets of ribs 18 and 19 are located on the internal surface 13. The ribs 18 and 19 would be wound about a mandrel and the axis 17, and then the tubular body 20 formed over the ribs 18 and 19.

[0060] The embodiment of Figure 8 is a modification of the embodiment of Figure 5. In this embodiment, the tubular body 1 1 has the ribs 14 as described with reference to Figure 1 , with the further tubular body 20 formed over the ribs 14. The ribs 18 and 19 are then formed over the outer surface 21 of the tubular body 20. Part of the duct 10 has been removed to expose the ribs 14 and body 20. [0061] In the embodiment of Figure 1 1, the duct 10 is a modification of the duct 10 of Figure 4. However in this embodiment there is a further outer tubular body 25 formed over the ribs 18 and 19. Again the tubular body 25 would be formed of carbon fibre wound about the axis 17, and is preferably formed of at least two layers, with the carbon fibre wound in opposite directions about the axis 17.

[0062] In Figure 13, there is schematically depicted a modification of the duct 10. In this embodiment, the duct 10 is of a rectangular transverse cross-section and has a structure similar to the duct of Figure 4. Accordingly it should be appreciated that the duct 10 can have any desired transverse cross-section including oval, square, rectangular and octagonal.

[0063] In the embodiment of Figures 14 and 15, the duct 10 includes a layer 30 of sheet material. The layer 30 in one embodiment prevents air passing transversely through the duct wall. The layer 30 is preferably a suspension layer aiding to bridge the ribs 14. For example the layer 30 may be of sheet material. In particular the layer 30 may have a carrier layer that is woven or non- woven and may include plastics material. Typically the layer 30 would be a composite film adhesive layer that would include a resin. The sheet material may be felt, tissue or light weight fibreglass cloth impregnated with resin, or may be a resin coating. The layer 30 may also assist in stiffening the duct 10 and/or aid in the manufacture of the duct 10.

Preferably, the layer 10 is at least substantially co-terminus with respect to the surfaces 12 and 13.

[0064] In respect of the previously described embodiments and with reference to Figure 9, preferably the ducting is formed with a socket end 24 that would engage an end portion 26 of the next adjacent duct 10 to provide for coupling of like ducts 10. Preferably, the carbon fibre forming the tubular bodies 1 1, 20 and 23 is formed of wound carbon fibre having a fire retardant property. Preferably, the ribs 14, 18, 19 and 22 are also formed of carbon fibre having fire retardant properties.

[0065] In Figure 16, there is schematically depicted a modification of the duct 10. More particularly but not exclusively the duct 10 of Figure 16 is a modification of the duct of Figure 3. In this embodiment the rib 14 is wound so as not to have a constant pitch. In.particular the rib 14 adjacent the ends of the duct 10 may have a smaller pitch relative the pitch of the rib 14 adjacent central portion of the duct 10. More particularly in respect of this embodiment, it should be appreciated that the ribs of other embodiments may also be configured so as to not have a constant pitch, again a pitch that diminishes towards the end extremities of the duct 10.

[0066] In Figures 17 and 18, there is schematically depicted a handle assembly 31. The handle assembly 31 is a part of any one of the previously described ducts 10.

[0067] In the particular embodiment of Figure 17, the handle assembly 31 includes a handle 32 in the form of a flexible strap. The handle 32 is secured to the outer surface 33 of the duct 10 by means of bolts 34. The bolts 34 pass through washers 35 as well as end portions of the handle 32, to also pass through reinforcing patches 36 as well as one or more tubular bodies 37 (such as bodies 1 1, 20, 23, 25, 37 and 38). The bolts 34 threadably engage inserts 38 that are preferably metal. The inserts 38 are located between the tubular bodies 37 and in particular are located between ribs 39. The ribs 39 may be formed so as to extend in a similar manner to the previously described ribs 14, 18, 19 and 22. Preferably, reinforcing patches 40 are also applied to the tubular bodies 37 adjacent the insert 38. Preferably, the reinforcing patches 36 and 40 are of a fabric construction impregnated with resin.

[0068] In the embodiment of Figure 18, the handle assembly 31 has the bolts 34 threadably engage a nut portion 41 that includes a spacer portion 42 essentially extending between the tubular bodies 37. The handle may be configured so as not to protrude through the surface 13.

[0069] Preferably, each of the tubular bodies 1 1, 20, 23, 25 and 37 is formed of resin and carbon fibre, the carbon fibre is in ribbon form and is wound in a spiral manner and may include carbon fibre wound in opposite directions about the axis 17. Preferably each tubular body 1 1 , 20, 23, 25 and 37 is preferably formed of at least two layers, with the layers having opposite winding directions about the axis 17. In that respect, the spiral structure can have a desired winding angle and may include multiple layers and different angles. Preferably, the layers would be joined at opposite ends. In further embodiments, the ribs 14 of Figures 1 to 6 may be formed on the inner surface 13.

[0070] In the above preferred embodiments the ribs, such as the ribs 14, 18, 19, 22 and 39, when extending longitudinally and angularly, have a pitch of 5mm to 50mm. [0071] The above describe preferred embodiments are described as employing carbon fibre. In that regard it should be appreciated other fibres may be used. As further examples glass fibre and resin, natural fibres and resin, or ARAMID® fibre and resin could be used.

[0072] By providing the above duct 10 with the above described ribs, the duct 10 has particular advantages including increase resistance to bending and increase resistance to (hoop) crushing.

[0073] The above ribs are described as being formed of carbon fibre. However the ribs may also be formed of other fibres including glass fibre, natural fibres and ARAMID® fibres, again impregnated with resin.