AU2012203275A1 - A duct assembly - Google Patents

Abstract

A duct assembly (10) to deliver a flowable substance under pressure into a port (422) of a substance receiving fitting (413) includes a tube (11) having a terminal end to engage with the port and through which the substance is to be delivered to the port. The tube (11) has a first length (12) and a second length (13). The second length (13) provides the terminal end. A securing device (15) is slidingly engaged with the tube (11) and adapted to engage the fitting (413) to inhibit relative movement between the terminal end and the port (422) during delivery of the substance. The securing device (15) is slideable along the tube (11) from an inactive position spaced from the terminal end and not to be engaged with the fitting (413), and an active position spaced from the inactive position towards the terminal end and to engage the fitting (413) to retain the terminal end engaged with the port (422). A user manipulated portion (18) is operatively associated with the securing device (15) so that a user may manipulate the securing device (15) to move the securing device (15) between the active and inactive positions.

Description

S&F Ref: P037728 AUSTRALIA PATENTS ACT 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT Name and Address DYWIDAG-Systems International Pty Limited, of Applicant: an Australian company, ACN 093 424 349, of 25 Pacific Highway, Bennett's Green, New South Wales, 2290, Australia Actual Inventor(s): Andrew Simon BOYCHUK Address for Service: Spruson & Ferguson St Martins Tower Level 35 31 Market Street Sydney NSW 2000 (CCN 3710000177) Invention Title: A duct assembly Associated Provisional Application Details: [33] Country: [31] Appl'n No(s): [32] Application Date: AU 2011902199 03 Jun 2011 The following statement is a full description of this invention, including the best method of performing it known to me/us: 584 5c(6336470_1) A DUCT ASSEMBLY Technical Field [0001] The present invention relates to strata control in civil engineering and mining operations and in particular relates to the installation of rock bolts (in the form of cable bolts) for securing the roof or wall of a mine, tunnel or other ground excavation. More particularly, the present. invention relates to an apparatus to deliver a flowable substance such as grout to a rock bolt for the post-grouting of a bolt. Background of the Invention [0002] To secure the roof and/or walls of underground mines, tunnels and other ground excavations, rock bolts in the form of long flexible cable bolts (otherwise referred to as strand bolts) are often utilised. In one form of installation, each cable bolt is fixed into a bore hole drilled into a rock face with both a two-component resin and cement grout. A resin cartridge containing the two-component resin is first inserted into the bore hole, followed by the cable bolt which is driven into the hole to puncture the resin cartridge. The cable bolt is rotated to mix the resin and form a point anchor securing the leading end of the cable bolt in the bore hole once the resin has set. The cable bolt is then pre-tensioned with a hydraulic jack and the trailing end of the cable bolt secured to the rock face at the opening of the bore hole utilising a barrel and wedge assembly that engages a bearing plate washer located against the rock face. A cement grout is then injected into the annular cavity between the cable bolt and the wall of the bore hole both to provide a degree of corrosion protection to the cable bolt and to provide for compressive load transfer between the wall of the bore hole and the cable bolt. [0003] Various different arrangements for injecting grout into the annular cavity have previously been proposed. In one cement grouting method, a grout tube is inserted into the bore hole only a short distance, such that the grout injected into the grout tube is pushed up through the annular cavity from adjacent the bore hole opening. To evacuate air from the bore hole while the cement grout is being pumped from the bottom, a breather tube (typically in the form of a small diameter plastic tube) is located in the annular cavity extending toward the top of the bore hole. The bore hole must also be sealed at the rock face to ensure that the injected grout is pumped toward the top of the bore hole rather than merely escaping out through the bore hole opening. The breather tube is also subject to damage during installation, and requires a relatively large annular cavity between the cable bolt and bore hole wall for location of the breather tube.

2 [0004] In an alternate cement grouting method, the grout tube extends from the bore hole opening to adjacent the top of the bore hole, such that grout injected through the grout tube flows down through the full length of the bore hole. Utilising this method, no breather tube is required and there is no need to seal the bore hole opening in the rock face. A large diameter bore hole is required to be drilled into the rock to house the grout tube in the annular cavity between the cable bolt and bore hole wall. Such a relatively large diameter hole is generally, however, not desired for anchoring the top portion of the cable bolt with resin as the annular cavity between the cable bolt and the bore hole should be as small as possible to achieve the best fixation of the cable bolt. A smaller annular cavity is also desired for effective load transfer between the cable bolt and bore hole wall via the cement grout. [0005] A particular disadvantage of some previous known methods and apparatus for delivering grout is that the grout is delivered axially through the barrel and wedge assembly. This requires the cable to be longitudinally hollow. This reduces the strength of the cable. Object of the Invention [0006] It is the object of the present invention to overcome or at least ameliorate one or more of the above disadvantages. Summary of the Invention [0007] The present invention provides a duct assembly to deliver a flowable substance under pressure into a port of a substance receiving fitting, the assembly including: a tube having a terminal end to engage with the port and through which the substance is to be delivered to the port, the tube having a first length and a second length, the second length providing said terminal end; a securing device slidingly engaged with the tube and adapted to engage the fitting to inhibit relative movement between the terminal end and the port during delivery of the substance, the securing device being slideable along the tube from an inactive position spaced from the terminal end and not to be engaged with the fitting, and an active position spaced from the inactive position towards the terminal end and to engage the fitting to retain the terminal end engaged with the port; and a user manipulated portion operatively associated with the securing device so that a user may manipulate the securing device to move the securing device between the active and inactive positions.

3 [0008] Preferably, the second length extends at least partly laterally from said first length. [0009] Preferably, the assembly further includes a retaining portion extending between the user manipulated portion and tube and operable to cause relative displacement therebetween to aid in retaining the securing device engaged with the fitting. [0010] Preferably, said user manipulated portion is an elongated rod extending generally parallel to said first length. [0011] Preferably, said securing device includes a first portion at least partly surrounding the first length so that the first length is retained therein but slidable relative thereto, and a second portion to generally encompass the fitting. [0012] Preferably, said first length has a coupling end with a coupling providing for securing to the first length a hose via which the substance is to be delivered to the tube. [0013] Also disclosed is a method of delivering grout to a roof bolt having a longitudinal axis, the bolt having a grout delivery port extending at least partly laterally relative to said axis, said method including the steps of: providing a source of grout under pressure; moving the grout in a first direction, the first direction having a major direction component generally parallel to said axis; and redirecting the grout from said first direction to said port in a further direction, said further direction being at least partly lateral relative to said axis. [0014] Preferably, said first direction is substantially parallel to said axis, and said further direction is generally perpendicular to said axis. Brief Description of the Drawings [0015] A preferred form of the present invention will now be described by way of example with reference to the accompanying drawings wherein: [0016] Figure 1 is a schematic bottom isometric view of a cable bolt assembly; [0017] Figure 2 is a schematic top isometric view of the cable bolt of Figure 1; 4 [0018] Figure 3 is a schematic bottom isometric view of a modification of the cable bolt of Figure 1; [0019] Figure 4 is a schematic top isometric view of the cable bolt of Figure 3; [0020] Figure 5 is a schematic side elevation of the cable bolt of Figures 1 and 2 located in a bore hole; [0021] Figure 6 is a schematic parts sectioned side elevation of the cable bolt of Figure 1; [0022] Figure 7 is a schematic isometric view of a fitting of the cable bolt of Figure 1; [0023] Figure 8 is a schematic bottom isometric view of the fitting of Figure 7; [0024] Figure 9 is a further schematic sectioned side elevation of the cable bolt of Figure 1; [0025] Figure 10 is a schematic bottom isometric view of a duct assembly to deliver grout under pressure to the cable bolt of Figures 1 to 9; [0026] Figure 11 is a schematic top isometric view of the assembly of Figure 10; [0027] Figure 12 is a schematic bottom isometric view of the cable bolt assembly and duct delivery assembly of Figure 10 in a disengaged position; [0028] Figure 13 is a schematic top isometric view of the cable bolt assembly and duct assembly as shown in Figure 12; [0029] Figure 14 is a schematic isometric view of the securing device of the duct assembly of Figure 10; [0030] Figure 15 is a schematic isometric view of the duct assembly of Figure 10; and [0031] Figure 16 is a schematic parts sectioned side elevation of the duct assembly and cable bolt shown in Figures 1 to 13.

5 Detailed Description of the Preferred Embodiment [0032] A cable bolt assembly 400 is shown in Figures 1 to 4. The assembly 400 includes a cable 410 extending along a longitudinal axis L between a cable leading end 410a and a cable trailing end 41 Ob, as well as a post-grouting apparatus 411. The apparatus 411 includes an elongated sleeve 412, a load bearing grout delivery fitting 413 and a seal 414. Engaged with the fitting 413 are wedges 415. The sleeve 412 includes a longitudinally extending tube 416 secured to the fitting 413 so as to extend longitudinally therefrom toward the end 410a and a sheath 417. Received within the tube 416 and extending therefrom is the sheath 417. As is illustrated in the Figures, the sheath 417 has an outer diameter enabling it to be received within the end extremity of the tube 416, but to surround the cable 410 while still providing a longitudinally extending annular passage 418 between the inner surface of the sheath 417 and the outer surface of the cable 40. If required, the sheath 417 may include corrugations 419 extending angularly about the axis L. [0033] The tube 416 would be typically formed of metal and fixed to the fitting 413. The sheath 417 would be secured to the end extremity of the tube 416 by an adhesive and/or an interference fit therewith. [0034] The tube 416 is sized so as to surround the cable 410 and to provide an annular longitudinally extending passage 420 between the cable 410 and the interior surface of the tube 416. [0035] The fitting 413 includes an end annular cavity 418 that communicates with the passage 420 that in turn communications with the cavity 418. The cable 410 extends through the cavity 418. Extending laterally from the cavity 413 is a grout port 422. [0036] The fitting 413 further includes a longitudinally extending passage 423 through which the cable 410 passes, with the passage 423 increasing in diameter past the wedges 415. The internal surfaces of the passage 423 adjacent the wedges 415 have an inclination relative to the axis L so as to match the external surfaces of the wedges 415. As best seen in Figure 19, the wedges 415 surround the cable 410. The passage 423 extends inwardly of the fitting 413 from the fitting trailing face 430.

6 [0037] The leading portion of the fitting 413 is arcuate in configuration so as to provide an end (leading) face 424 that bears against the bearing plate washer 425. The cavity 418 extends upwardly of the fitting 413 from the face 424. [0038] Surrounding the passage 423 is an annular slot 426 within which there is located an annular resilient seal 427 that engages the external peripheral surface of the cable 410 to aid in sealingly connecting the fitting 413 and cable 410. [0039] In operation of the above cable bolt assembly 400, the bore hole 200 is drilled into the rock face 201. A resin cartridge 203 containing a 2-component resin is then inserted into the bore hole 200, followed by the cable bolt assembly 400. The leading end 41 Oa engages the cartridge 203 to move it longitudinally of the bore hole 200. The cable bolt assembly 400 is mounted on the dolly of a regular cable bolt insertion equipment, with the drive head 428 engaged and driven by the dolly. The cable leading end 410a thus compresses the resin cartridge 203 against the hole blind end, rupturing the frangible casing of the cartridge 423 and allowing the 2-component resin to mix. As the cable 410 is thrust further towards the bore hole blind end the resin flows down over the leading region of the cable 410. Spiral wire 429 acts to pump the resin towards the bore hole blind end as the cable 410 is rotated about the axis L. [0040] The fitting 413 and wedges 415 rotate with the cable 410 to minimise damage to the seal 427. The plate 425 may or may not rotate with the cable 410. [0041] Once the resin has been mixed and rotation of the cable 410 ceased, the resin is allowed to cure thereby anchoring the leading region of the cable 410 within the bore hole 200. [0042] Once the resin has cured, the post-grouting apparatus 411, bearing plate washer 425 and wedges 415 are assembled onto the trailing region of the cable 410 if not already assembled. [0043] The cable 410 is then pre-tensioned by hydraulic cable tensioning equipment engaging the cable 410 adjacent the end 410b. While this is occurring the wedges 415 are driven further into the passage 423 so as to engage in a clamping manner the external surfaces of the cable 410 to securely connect the fitting 413 to the cable 410 which in turn compresses the washer 425 against the face 210.

7 [0044] Once pre-tensioning has been completed, a duct is connected to the port 422 for delivery of grout to the cavities 421, 420 and 418 for delivery to the annular end opening 431 at the end extremity of the sheath 417. The grout flows upwardly toward the resin now surrounding the end extremity of the cable 410, and then downwardly over the outer surfaces of the sheath 417 and tube 416. The grout is then allowed to set. [0045] Preferably, the port 422 extends generally perpendicular to the longitudinal axis L. However it should be appreciated that the port 422 need only have some lateral direction of extension relative to the axis L. [0046] It may also be advantageous to locate between the wedges 415 and seal 426 a backing ring that abuts the end extremity of the wedges 415 and the seal 416 to aid in supporting the seal 416 and to perhaps compress the seal 416 so as to urge it into sealing contact with the outer surface of the cable 410. [0047] If the cable bolt assembly 400 is to be installed in an assembled condition, preferably the wedges 415 would be partly driven into the fitting 414 so as to apply compression force to the cable 410 to retain the fitting 414 and wedges 415 secured to the cable 410. Just prior to installation the washer 425 would be placed on the fitting 414 and the cable bolt assembly 400 inserted. [0048] It may be advantageous to infuse or impregnate the cable 410 with a resin to inhibit longitudinal movement of liquid from the cavity 421 toward the wedges 415. In that regard it should be appreciated the cable 410 has internal longitudinal extending passages or recesses that would possibly duct liquid past the seal 412. [0049] In Figures 10 to 15 of the accompanying drawings there is schematically depicted a duct assembly 10. The assembly 10 is to deliver grout under pressure to a cable bolt. In one particular form, the assembly 10 is intended to deliver grout under pressure to the cable bolt 400 described with reference to Figures 1 to 9. In that regard it should be appreciated the assembly 10 is intended to deliver grout under pressure to any roof bolt having a port that extends at least partly laterally relative to the longitudinal axis of the cable bolt assembly. [0050] The assembly 10 includes a tube 11 having a generally linear first length 12 that is secured to a second length 13. In this embodiment the second length 13 extends generally 8 perpendicular to the length 12 and provides a terminal end that is inserted in the port 422. The other end of the length 12 is provided with a coupling 14 that is attached to a hose via which grout under pressure is delivered to the tube 12 for delivery to the second length 13 so that grout under pressure is delivered to the port 422. [0051] Slidably mounted on the tube 11 is a securing device 15 that includes a first portion 16 that substantially encompasses the tube 11 and is slidable therealong while being captively located with respect to the tube 11. The device 15 includes a second portion 17 that is generally circular in configuration and is to encompass the fitting 413. Preferably the portion 17 is slidable over the fitting 413 but is a close fit relative thereto. [0052] Fixed to the device 15 is a user manipulated portion in the form of a rod 18 that in this embodiment extends generally parallel to the tube 11 and is substantially co-extensive relative thereto. [0053] Extending between the tube 11 and rod 18 is a retaining portion 24 in the form of a band 19 that is slidable relative to both the tube 11 and rod 18, or is fixed to one of them. [0054] A user of the assembly 10 attaches a hose to the coupling 14 and then grips the tube 11 and rod 18 so as to manipulate the second length 13 and insert the second length 13 in the port 422. Thereafter the rod 18 is moved so that the device 15 slides along the tube 11. The fitting 413 is located so that the second portion 17 securely fixes the second length 13 (terminal end) in the port 422. Grout then flows in the direction 20. [0055] The second length 13 extends at least partly laterally relative to the first length 12, and axis L, that is at least partly laterally relative to the direction 20 that the grout flows. In this embodiment, the lateral flow is in the direction 21. [0056] The above described preferred embodiment, the securing device 15 may be flexible or rigid, but more preferably is formed of generally rigid material such as metal or plastics. The band 19 may also be formed of rigid or flexible material, but more preferably is formed of flexible material. [0057] In the above described preferred embodiment, the securing device 15 engages the tube 11 and fitting 413 to retain the second length 13 engaged with the port 422.

9 [0058] The retaining portion 24 is operatively associated with end portions 22 and 23 of the tube II and rod 18 to aid in retaining the securing device 15 fixed in the position shown in Figure 16, that is the securing device 15 maintaining the second length 13 engaged with the port 422. In this particular embodiment the retaining portion 24 is the band 19. Preferably the band 19 is changeable in operative length by operation of a buckle 25 so as to urge the end portions 22 and 23 together so that the securing device 15 is urged into a more secure contact with the fitting 413. In an alternative embodiment, the retaining portion 24 may be a mechanism that urges the end portion 22 and 23 apart again to urge the securing device 15 into secure engagement with the fitting 413. [0059] The above described preferred embodiment has a number of advantages including enabling an operator of the assembly 10 to stand on the ground level below the mine roof and still manipulate the second length 13 into engagement with the port 422. A still further advantage is once the securing device 15 is engaged with the fitting 413, the grout under pressure can then be delivered to the port 422 without the operator being present. The operator could move to the next assembly 10 to continue a similar operation while grout is being delivered to the previous cable bolt assembly 400. A future advantage is enabling the grout to pass longitudinally of the cable 410 adjacent the external peripheral surface of the cable 410 as opposed to internally of the cable. [0060] In operation of the assembly 10, when grout under pressure is applied to the tube 11, the device 15 inhibits relative movement between the tube 11 and fitting 413. [0061] When grouting has been completed, the rod 18 is again gripped and the device 15 is slidably moved along the tube 11 until the device 15 is removed from engagement with the fitting 413. The second length 13 can then be removed from within the port 422.

Claims (6)

1. 2. The duct assembly of claim 1, wherein said second length extends at least partly laterally from said first length.
2. 3. The assembly of either one of claims I and 2, further including a retaining portion extending between the user manipulated portion and tube and operable to cause relative displacement therebetween to aid in retaining the securing device engaged with the fitting.
3. 4. The assembly of either one of claims 2 and 3, wherein said user manipulated portion is an elongated rod extending generally parallel to said first length.
4. 5. The assembly of any one of claims I to 4, wherein said securing device includes a first portion at least partly surrounding the first length so that the first length is retained therein but slidable relative thereto, and a second portion to generally encompass the fitting.
5. 6. The assembly of any one of claims 1 to 5, wherein said first length has a coupling end with a coupling providing for securing to the first length a hose via which the substance is to be delivered to the tube. 11
6. 7. A duct assembly substantially as hereinbefore described with reference to the accompanying drawings. Dated 1 June 2012 DYWIDAG-Systems International Pty Limited Patent Attorneys for the Applicant/Nominated Person SPRUSON & FERGUSON