AU2010201306A1 - A Plug - Google Patents

Description

AUSTRALIA Patents Act 1990 COMPLETE SPECIFICATION Standard Patent Applicant(s): Ian McKay Invention Title: A Plug The following statement is a full description of this invention, including the best method for performing it known to me/us: -2 A PLUG Field of the Invention 5 The present invention relates to a plug, and in particular, but not exclusively, to a plug that may be used in filling a tubular member or hole with a flowable substance where the member or hole is inclined so that the flowable substance would otherwise flow out by action of gravity. 10 Background of the Invention In mining and civil engineering it is sometimes necessary to fill a tubular member or hole with a flowable substance such as grout. For example grout may be injected into a tubular member inserted into an up hole to assist in 15 anchoring the tubular member in the up hole. In order to prevent or at least minimise the outflow of grout from the tubular member/hole a greater proportion of the active component(s) of the grout or, a thickener, is added to the grout. However this increases the cost of the grout itself and also leads to higher maintenance and downtime due to increased occurrences of clogging and 20 blocking of pumps and other machines used in the delivery of the grout. Summary of the Invention In one aspect the present invention provides a plug comprising: 25 a plug body provided with a first hole and an air bleed passage each extending between opposite ends of the body; and, a valve coupled to the body and arranged to allow material to flow in one direction only through the first hole. 30 The valve may be a self closing valve and configured to allow the material to pass through the plug body into a hole or tubular member into which the plug is inserted and to substantially prevent a back flow of the material through the first hole. 35 The valve may comprise (a) a flap of a resilient material coupled to the plug body; or (b) a flap of material resiliently coupled to the plug body. 22373671 (GHMatters) 1/04/10 -3 The plug may comprise a projection to which the flap is coupled. The projection may be integrally formed with the plug body. 5 The plug may comprise an inflatable portion coupled to the plug body, and in fluidal communication with the first hole and the second hole. In a second aspect the invention provides a plug comprising: a plug body having a first hole and an air bleed passage each extending 10 between opposite ends of the plug body; a valve coupled to the plug body and arranged to selectively open and close the first hole; and, an inflatable portion coupled to the plug body and in fluidal communication with at least the first hole. 15 The inflatable portion may be capable of increasing in length upon inflation. The inflatable portion may additionally or alternately be capable of increasing in width upon inflation. 20 The inflatable portion may comprise a side wall and an end wall extending across the side wall at an end distant the plug body. The end wall may be frangible wherein the end wall is configured to break or 25 rupture after at least partial inflation of the inflatable portion. The inflatable portion may be formed integrally with the plug body. The end wall may be provided with an opening for receiving a conduit. 30 In one embodiment the plug may comprise an opening formed in the end wall, and a conduit that extends through the second hole and through the opening in the end wall. 35 The plug may comprise a rigid liner inserted in the first hole. The plug body may be formed with a progressively decreasing outer diameter in 22373671 (GHMatters) 1/04110 -4 an axial direction toward an in-hole end of the plug. An outer circumferential surface of the plug body may comprise a plurality of axially spaced radially extending ribs wherein successive ribs have a 5 progressively decreasing maximum outer diameter in the direction of decreasing outer diameter of the plug body. Each rib may be formed with a first circumferential surface of constant diameter. 10 Each rib may be additionally formed with first inclined circumferential surface extending from the first circumferential surface of constant diameter in a direction toward the central longitudinal axis of the plug body. 15 Each rib may also comprise a second circumferential surface of constant diameter extending from the first inclined surface. Each rib may also be formed with a second inclined circumferential surface extending from the second circumferential surface in a direction radially away 20 from the central longitudinal axis toward a first circumferential surface of constant diameter of an adjacent rib. The plug body may be provided with a radially extending flange at a larger diameter end of the body. 25 The air bleed passage may comprise a groove or channel formed on an outer surface of the plug body. Alternately the air bleed passage comprises a second hole extending through 30 the plug body. In a third aspect the invention provides a method of filling a hole or tubular member with a flowable substance, the method comprising: inserting a plug according to the first or second aspects of the invention 35 into the hole or tubular member; passing a conduit into the first hole in the body; delivering a flowable substance through the conduit into the hole or 22373671 (GHMatters) 1/04110 tubular member; opening the valve by either pushing the conduit through the valve or by action of pressure of the flowable substance; withdrawing the conduit; 5 bleeding air from the hole or tubular member through the air bleed passage while delivering the flowable substance into the hole or tubular member; and, operating the closure to prevent flow of the flowable substance out of the hole or tubular member through the first hole in the body. 10 Bleeding air may comprise installing a bleed tube in the hole which extends to and is in fluid communication with the air bleed passage in the plug. Installing the bleed tube may comprise installing the bleed tube in the hole prior 15 to inserting the plug into the hole or tubular member. Brief Description of the Drawings An embodiment of the present invention will now be described by way of 20 example only with reference to the accompanying drawings in which: Figure 1 is a cross section view of one embodiment of the plug; Figure 2 is a plan view of an upper face of the plug shown in Figure 1; 25 Figure 3 is an enlarged view of detail X shown in Figure 1; Figure 4a is a cross section view of a second embodiment of a plug in accordance with the present invention; 30 Figure 4b is an end view of the plug shown in Figure 4a; Figure 4c is an elevation view of the plug along plane AA shown in Figure 4a; 35 Figure 4d is a cross section view of an insert incorporated in the plug shown in Figures 4a - 4c; 2237367_1 (GHMatters) 1/04110 -6 Figure 5 is a cross section view of the plug shown in Figures 4a - 4c with an inflated portion of the plug in a deflated state; Figure 6 shows the plug of Figure 5 in a partially inflated state; 5 Figure 7 is a plan view of the plug inflated to an extent where an inflatable portion of the plug bursts; Figure 8 is a schematic representation of a split pin in a hole formed in a body 10 of rock and into which embodiments of the plug can be inserted; Figure 9 illustrates a method of use of the first embodiment of the plug; and, Figures 10 - 12 illustrate a method of use of the second embodiment of the 15 plug. Detailed Description of Preferred Embodiments Referring to Figures 1 and 2 of the accompanying drawings, an embodiment of 20 a plug 1 0A in accordance with the present invention comprises a plug body 12 in which is formed a first hole 14 and an air bleed passage 15. The first hole 14 and passage 15 extend in an axial direction between opposite ends of body 12. A valve 16 is coupled to or otherwise supported by body 12 and is located near an end 18 of the hole 14. 25 The plug body 12 is in a general form of a solid cylinder having an outer circumferential surface 20 with a planar radial surface 22 at an in-hole end of the body 12. The end 18 of the hole 14 opens onto the surface 22. An opposite end of the body 12 is also formed with a planar radial surface 24 about 30 which a circumferential flange 24a is provided. The flange 24a extends radially from the outer circumferential surface 20 of the body 12. The body 12 is tapered to decrease in outer diameter in a direction from the flange 24 to the surface 22. 35 The hole 14 is formed in an axial direction in the body 12 opening at the end 18 onto the surface 22 and at an opposite end 26 onto the surface 24. The hole 14 is shown as being radially offset from a longitudinal axis of the body 12 2237367_1 (GHMatters) 1/04/10 -7 however this is not an essential requirement and it is possible in an alternate embodiment for the hole 14 to be coaxial with the longitudinal axis of the body 12. 5 The air bleed passage 15 extends between opposite ends of plug body 12 and more specifically opens onto the surfaces 22 and 24 to provide a bleed path for air when flowable substance is injected into a hole or tubular member through the plug body 12. 10 The valve 16 is in the form of a flap valve which is coupled to the body 12 by a projection 33 extending from the surface 22. The projection 33 may comprise an integrally formed post or "T" piece. The flap valve 16 operates as a one way valve allowing material to flow through the first hole 12 in the direction from the flange 24 to the surface 22, while substantially preventing a back flow of the 15 material. The flap valve comprises a flap 35 as configured to overlie the first hole 12 but can be displaced from this position to allow flow of material through the hole 12. Figure 1 depicts in cross hatching the flap 35 in a closed position in which it lies on the surface 22 and covers the hole 12, and an open position shown in phantom line where the flap 35 is displaced or pushed upwardly from 20 the hole 12. This displacement may typically occur by the insertion of a hose through the hole 12 through which material is injected into a hole or tubular member closed by the plug 10. Alternately the pressure of the material may by itself open the valve 16. 25 The flap may be either made of a resilient material such as rubber so as to naturally spring back to the closed position when the flow of material through the hole 12 has ceased and/or the hose used to inject the material is withdrawn from the hole 12. Alternately, the flap may be made of any material and resiliently coupled or otherwise biased so as to return to the closed position. 30 The outer circumferential surface 20 of the plug 10 is formed with a plurality of axially spaced radially extending ribs 37. The ribs have progressively decreasing maximum outer diameter in the direction along the plug body from the flange 24a to the surface 22. Each rib is formed with a first circumferential 35 surface 39 of constant diameter, a contiguous first inclined circumferential surface 41 extending from the surface 39 in a direction toward the central longitudinal axis of the plug body 12, a second circumferential surface 43 of 22373671 (GHMatters) 1104110 -8 constant diameter (the diameter being less than the diameter of the surface 39), and a contiguous second inclined circumferential surface 45 which extends radially away from the central longitudinal axis of the plug body 12 toward the first circumferential surface of constant diameter of an adjacent rib 37. In this 5 particular embodiment the second inclined circumferential surface 45 lies in a radial plane, i.e. perpendicular to a longitudinal axis of body 12. In one embodiment, the length of each rib 37 may be in the order of 3mm with the radial distance between the first and second circumferential surfaces 39 and 43 in the order of 0.75mm. The angle of inclination of the surface 41 may be 10 between 30 and 60 degrees. Figures 4a - 7 depict a second embodiment of the plug 10B. In the description of the embodiment of the plug 1 OB, the same reference numbers will be used for the same or equivalent features of the plug 10, but with the addition of the 15 letter "B". The plug 10B comprises a plug body 12B in which is formed a first hole 14B extending in the axial direction and opening onto a planar surface 22B at one end of the plug body. An opposite end 24B of the plug body 12B is formed with 20 a surface 24B planar and a radially extending flange 24aB. An air bleed passage 15B also extends axially through the body 12B opening onto the surfaces 22B and 24B. The plug body 12B is also generally tapered so as to reduce in diameter in a direction from the surface 24B to the surface 22B. However a portion 13 of the body 12B which leads to the surface 22B is formed 25 of a constant outer diameter. The plug 10B is also provided with a valve 16B having a plurality of (in this case four) leaves or flaps 35B that are hinged along one edge to either the surface 22B or an interior surface of the hole 14B. The flaps 35B are spaced apart to 30 form small radial gaps G therebetween. The valve 16B can be opened by: inserting a hose through the hole 14B to hinge the leaves or flaps 35B upwardly; or, fluid pressure of the material injected into hole 14B. When the hose is withdrawn, the leaves 35B are able to return to a position where they substantially close the hole 14B. 35 Substantive differences between the plug 1OB and the plug 1OA resides in the provision in the plug 1OB of an inflatable or expandable portion 75, and a rigid 22373671 (GHMatters) 1/04/10 -9 sleeve 17 lining the inside of hole 14B. The inflatable portion 75 is shown in Figures 4a and 5 in a collapsed or deflated state. In this configuration, the portion 75 has a first or minimum axial length 5 and a first or minimum diameter. The portion 75 can however be inflated as shown progressively in figures 6 and 7 so as to increase in one or both of length and diameter. The portion 75 is formed with a side wall 19, and an end wall 21 extending across the side wall 19 at an end distant the surface 22B. The end wall 21 is formed with an opening 23. The side wall 19 may be in the 10 form of a concertina which, when the portion 75 is uninflated, is in a collapsed state, and when the portion 75 is inflated, is in an extended state. The end wall 21 is constructed to be frangible so as to break or burst preferentially to the side wall 19 after the portion 15 has inflated or expanded 15 beyond a burst point, shown for example in Figure 7. This may be achieved by making the side wall 21 from the same but thinner material as a side wall 19, or providing lines of weakness and/or small perforations in the end wall 21. In one form of the plug 1 OB, the inflatable portion 75 is formed integrally with 20 the plug body 12B. That is, the portion 75 and body 12B may be moulded as a single piece. However it is envisaged that in an alternate embodiment, the expandable portion may be made separately from and subsequently attached to the body 12B. 25 The sleeve 17, being rigid, maintains its inner diameter when the plug 1OB is inserted into a hole or split pin. This enables easy insertion and retraction of a hose into the hole 14B, which may otherwise be difficult or impossible if the hole 14B was deformed by radial compression of the body 12B when inserted into a hole or split pin. 30 Prior to describing a method of use of the plugs a brief description of a typical split pin 32s is provided with reference to Figure 8. This figure depicts the split pin 32s in an up hole 32 formed in a back 36 of a tunnel 38. The split pin 32s is in the general form of a steel tube provided with a longitudinal slot 50 extending 35 along the whole of its length. The split pin 32s has a tapered end 52 that is initially inserted into hole 32 and thus is closest to a toe 40 of the hole 32 after full insertion of the split pin 32S. Near but slightly inboard of an opposite end of 2237367_1 (GHMatters) 1/04/10 -10 the split pin 32S is a ring flange 54. The ring flange 54 abuts with an end plate 56 that bears against the back 36 in the region surrounding the collar of the hole 32. 5 In Figure 8 (and subsequent Figures 9 to 12) for the sake of clarity hole 32 is shown as having a diameter greater than the diameter of the split pin 32S. However in practice the converse is true, with the split pin 32S having a slightly larger outer diameter than the inner diameter of the hole 32. When the split pin 32S is inserted into the hole 32, it is radially compressed and thereby exerts a 10 reactive radial force on the hole. The radial compression reduces the width of, but does not close, the longitudinal slot 50. As is most clearly apparent from Figure 10, a portion 58 of the split pin 32S extends from the back 36. The portion 58 includes a length of the slot 50 which provides a path for grout to leak from the hole 52. 15 Figure 9 depicts one possible application of embodiments of the plug 1 0A. In Figure 9, an up hole 32 is shown formed in the back 36 of the tunnel 38. The hole 32 extends into a body of rock 38 and is formed with a toe 40 and a collar 42. A rock anchor in the form of split pin 32S is inserted into hole 32. 20 The hole 32 is to be filled with a flowable substance such as grout 44. In order to fill the hole 32 with the grout 44, an air bleed tube 48 is inserted into air bleed passage 15 and split pin 32S until it reaches the toe 40 and pulled back a short distance, for example 10 - 100mm. An opposite end of the bleed tube 48 is 25 then inserted into passage 15 in the plug 10A and the plug 10A is now inserted into the split pin 32S. The plug 10A is inserted with the surface 22 first. In order to fill the hole 32 and split pin 32S with the grout 44, a delivery conduit 46 is passed through the hole 14 in the body 12. Ideally, although not necessarily, the conduit 46 is inserted into the hole 14 so as to extend beyond the surface 30 22 and thus positively open the valve 16. In one specific embodiment the conduit 46 may be inserted until it reaches the toe 40, then pulled back a small distance of say 100 - 200mm. The grout is now be pumped into the split pin 32S and the hole 32. The plug body 12 blocks the length of the slot 50 in portion 58 of the split pin thereby preventing leaking of grout from this length of 35 the slot 50. When the split pin 32S and hole 32 have been filled with grout 44 conduit 46 is 22373671 (GHMatters) 1/04110 -11 withdrawn. During this process, flap 35 of the flap valve 16 will return to its closed position where it overlies the hole 14A preventing the out flow of grout 44 when the delivery pipe 46 is withdrawn from the plug 10A. 5 Figures 10 to 12 depict the method of use of the plug 1 OB which is substantially the same as that for plug 10 described above but with the following differences or variations. The breather tube 48 is be pre-inserted into the split pin 32S/hole 32 before the plug 1OB is inserted. The distal end of the breather tube is inserted until it hits the toe 40 of the hole 32 then retracted a small distance. An 10 end of the tube 48 closest the collar of the hole 32 is passed through the opening 23 in the inflatable portion 15 and subsequently passed into the hole 31B. Plug 10B is now inserted into the split pin with the inflatable portion 75 first. Plug 1 OB is held by a friction fit arising from its tapered outer circumferential surface 20. Prior to the grout being injected into the split pin 42 15 via a hose 46, a gap may exist between the side wall 19 of the inflatable portion 75 and an inside surface of the split pin 32S. Thus, the length of the slot 50 in the portion 58 of the split pin 32S is not sealed. However sealing is achieved by inflating the inflatable portion 75 by use of the grout that is to be injected into the split pin 32S and hole 32. This is accomplished by first inserting the hose 20 46 into the hole 14B to a position where it may physically open the valve 16B as shown in Figure 11, but resides within the confines of the inflatable portion 75. Next, grout is pumped through the hose 46 which initially has the effect inflating the inflatable portion 75 to increase its length and diameter as shown progressively in Figures 11 and 12. The inflation of the inflatable portion 75 25 now seals the length of the slot 50 in the portion 58. Continued pumping of grout through the hose 46 eventually causes the end wall 21 of the inflatable portion 75 to rupture so that the grout can now flow into the remainder of the split pin 32S and the hole 32. Once the hole 32 is filled, the hose 46 is withdrawn causing the closure 16B to close preventing a back flow of grout 30 through the hole 14B. As the hole 32 fills with grout air from inside the hole 32 is displaced and flow out of the hole 32 through the breather tube 48. The above described embodiments of the plug 1 0A and 1 OB provide a simple and effective manner for filling an hole or tubular element with a flowable 35 substance and preventing substantial outflow or leakage of the flowable substance. 2237367_1 (GHMatters) 1/04/10 -12 Now that embodiments of the invention have been described in detail it will be apparent to those skilled in the relevant arts that numerous modifications and variations may be made without departing from the basic inventive concepts. For example the air bleed passage 15 is depicted as a through hole passing 5 axially through the plug body 12. However this hole may be reconfigured as a groove or channel formed on the outer circumferential surface 30 of the body 12. The channel may be either: longitudinal, extending in the axial direction from the surface 22 to the face of the flange 24; or alternately, formed in a spiral path winding around the circumferential surface 20. 10 The body 12A, 12B may be made from numerous materials including but not limited to wood, rubber or plastics materials such as acetyl. While the present embodiment is depicted and described as being inserted into a split pin disposed in an up hole for the purpose of filling the up hole with grout it may be 15 used in other applications. For example instead of being inserted directly into an up-hole it may be inserted into a tube or spilt pin previously installed in an up hole; or used for in the filling of up holes with explosives or propellants. 22373671 (GHMatters) 1104/10

Claims (29)

1. A plug comprising: a plug body provided with a first hole and an air bleed passage each 5 extending between opposite ends of the body; and, a valve coupled to the body and arranged to allow material to flow in one direction only through the first hole.

2. The plug according to claim 1 wherein the valve is a self closing valve 10 and configured to allow the material to pass through the plug body into a hole or tubular member into which the plug is inserted and to substantially prevent a back flow of the material through the first hole.

3. The plug according to claim 1 or 2 wherein the valve comprises (a) a flap 15 of a resilient material coupled to the plug body; or (b) a flap of material resiliently coupled to the plug body.

4. The plug according to claim 3 comprising a projection to which the flap is coupled. 20

5. The plug according to claim 4 wherein the projection is integrally formed with the plug body.

6. The plug according to any one of claims 1 to 5 comprising an inflatable 25 portion coupled to the plug body, and in fluidal communication with the first hole and the second hole.

7. A plug comprising: a plug body having a first hole and an air bleed passage each extending 30 between opposite ends of the plug body; a valve coupled to the plug body and arranged to selectively open and close the first hole; and, an inflatable portion coupled to the plug body and in fluidal communication with at least the first hole. 35

8. The plug according to claim 6 or 7 wherein the inflatable portion is capable of increasing in length upon inflation. 22373671 (GHMatters) 1/04/10 - 14

9. The plug according to any one of claims 6 to 8 wherein the inflatable portion is capable of increasing in width upon inflation. 5

10. The plug according to any one of claims 6 to 9 wherein the inflatable portion comprises a side wall and an end wall extending across the side wall at an end distant the plug body.

11. The plug according to claim 10 wherein the end wall is frangible wherein 10 the end wall is configured to break or rupture after at least partial inflation of the inflatable portion.

12. The plug according to any one of claims 6 to 11 wherein the inflatable portion is formed integrally with the plug body. 15

13. The plug according to any one of claims 10 to 12 wherein the end wall is provided with an opening for receiving a conduit.

14. The plug according to any one of claims 10 to 12 comprising an opening 20 formed in the end wall, and a conduit that extends through the second hole and through the opening in the end wall.

15. The plug according to any one of claims 1 to 14 comprising a rigid liner inserted in the first hole. 25

16. The plug according to any one of claims 1 to 15 wherein the plug body is formed with a progressively decreasing outer diameter in an axial direction toward an in hole end of the plug. 30

17. The plug according to claim 16 wherein an outer circumferential surface of the plug body comprises a plurality of axially spaced radially extending ribs wherein successive ribs have a progressively decreasing maximum outer diameter in the direction of decreasing outer diameter of the plug body. 35

18. The plug according to claim 17 wherein each rib is formed with a first circumferential surface of constant diameter. 22373671 (GHMatters) 1/04/10 -15

19. The plug according to claim 18 wherein each rib is formed with first inclined circumferential surface extending from the first circumferential surface of constant diameter in a direction toward the central longitudinal axis of the plug body. 5

20. The plug according to claim 19 wherein each rib is formed with a second circumferential surface of constant diameter extending from the first inclined surface. 10

21. The plug according to claim 20 wherein each rib is formed with a second inclined circumferential surface extending from the second circumferential surface in a direction radially away from the central longitudinal axis toward a first circumferential surface of constant diameter of an adjacent rib. 15

22. The plug according to any one of claims 16 to 21 wherein the plug body is provided with a radially extending flange at a larger diameter end of the body.

23. The plug according to any one of claims 1 to 22 wherein the air bleed passage comprises a groove or channel formed on an outer surface of the plug 20 body.

24. The plug body according to any one of claims 1 to 22 wherein the air bleed passage comprises a second hole extending through the plug body.

25 25. A method of filling a hole or tubular member with a flowable substance, the method comprising: inserting a plug according to any one of claims 1 to 24 into the hole or tubular member; passing a conduit into the first hole in the body; 30 delivering a flowable substance through the conduit into the hole or tubular member; opening the valve by either pushing the conduit through the valve or by action of pressure of the flowable substance; withdrawing the conduit; 35 bleeding air from the hole or tubular member through the air bleed passage while delivering the flowable substance into the hole or tubular member; and, 2237367_1 (GHMatters) 1/04/10 - 16 operating the closure to prevent flow of the flowable substance out of the hole or tubular member through the first hole in the body.

26. The method according to claim 25 wherein bleeding air comprises 5 installing a bleed tube in the hole which extends to and is in fluid communication with the air bleed passage in the plug.

27. The method according to claim 26 wherein installing the bleed tube comprises installing the bleed tube in the hole prior to inserting the plug into the 10 hole or tubular member.

28. A plug substantially as herein described with reference to and as illustrated in the accompanying drawings. 15

29. A method of filling a hole or tubular member with a flowable substance, the method substantially as herein described with reference to and as illustrated in the accompanying drawings. 22373671 (GHMatters) 1/04110 -16 operating the closure to prevent flow of the flowable substance out of the hole or tubular member through the first hole in the body. 26. The method according to claim 25 wherein bleeding air comprises 5 installing a bleed tube in the hole which extends to and is in fluid communication with the air bleed passage in the plug. 26. The method according to claim 26 wherein installing the bleed tube comprises installing the bleed tube in the hole prior to inserting the plug 10 into the hole or tubular member. 27. A plug substantially as herein described with reference to and as illustrated in the accompanying drawings. 28. A method of filling a hole or tubular member with a flowable substance, the method substantially as herein described with reference to and as 15 illustrated in the accompanying drawings. 2237367_1 (GHMatters) 1/04/10