AU2006201659B2 - Variable Discharge Valve Control Mechanism - Google Patents

Description

2006 19:50 Wallington-Dummer Sydney No.5056 P. 4 P/00/009 Regulation 3-2

AUSTRALIA

Patents Act 1990 COMPLETE SPECIFICATION Invention Title: VARIABLE DISCHARGE VALVE CONTROL MECHANISM The invention is described in the following statement, including the best method of performing it known to us: Our Ref: 062003 COMS ID No: SBMI-03364679 Received by IP Australia: Time 19:01 Date 2006-04-20 23 Jul 2008 17:02 Wrayd Bunburyj Fax 97914133 p.

0 -2- "Variable Discharge Valve Control Mechanism" Field of the Invention The present invention relates to valves for aerosol cans and, more particularly, to 'kn release valves for aerosol cans provided with selectable flow rates for the 5 inflation of bore hole plugs.

IN Background Typically, explosive charges for mining and other excavation activities, are placed in boreholes and frequently such charges are supported at some point below the surface, that is at some desired depth in the borehole. Inflatable plugs in the form of gas tight bags are used for this purpose. The plug is lowered to a desired depth and inflated such that it becomes firmly engaged with the sides of the borehole.

Typically, inflation is by means of an aerosol canister associated with the bag and arranged so as to discharge its pressurised contents into the bag during the descent of the bag down the borehole.

A common problem experienced with such arrangements is that in some situations the bag can inflate too quickly. For example, because aerosol gasses are temperature sensitive, on a hot day the gas passes from the canister at an accelerated rate, causing the plug to lodge at a point higher than intended.

Alternatively, inflation may be so slow that the bag needs to be retained at a desired level by means of an attached line for an undesirably long period.

It is an object of the present Invention to address or at least ameliorate some of the above disadvantages.

COMS ID No: ARCS-199474 Received by IP Australia: Time 18:15 Date 2008-07-23 23 Jul 2000 17:02 Wra j Bunbur j Fax 23 ul208 7:2 raj unurj ax97914133 P.S 0 0 Disclosure of the Invention ci Throughout this specification and claims, unless the context requires otherwise, N- the word "comprise" or variations such as "comprises" or "comprising", wili be understood to imply the inclusion of a stated integer or group of integers but not the exclusion of any other integer or group of integers.

VaO o According to one aspect the invention resides in ,an aerosol canister control 0 upon which the control mechanism is in use to be mounted, the one end having a discharge nozzle, the discharge nozzle having an outlet, the discharge nozzle associated with a valve, whereby displacement of the discharge nozzle to a discharging state will open the valve to -permit the contents of the canister to escape through the outlet, said control mechanism comprising a body which is adapted to be mounted to the one end, the control mechanism further comprising a first member supported by the body for axial slidable movement wherein in use the first member is positioned to be generally coaxial with to the canister and the discharge nozzle and the slidable movement of the first member is generally parallel to the central axis of the canister, wherein in use on the body being supported on the one end Ihe first member is axially movable between a first position at which the discharge nozzle is closed and a second position at which the first member has caused said displacement of the discharge nozzle, the first member adapted to cooperate with the outlet to receive the contents of the canister when the discharge nozzle has been displaced, the first member further supported from the body to be rotatable about its central axis, the first member being formed with at least one first orifice positioned to be capable of being aligned to be able to communicate with the outlet on said rotation of the first member to a discharging position, a first retention means provided between the first member and. the body adapted to retain the first member in its discharging position.

According to a preferred feature of the invention the first member is biased to its first position.

COMS ID No: ARCS-199474 Received by IP Australia: Time 18:15 Date 2005-07-23 23 Jul 2008 17:02 Wra j Elunbur j Fax 23 ul200 1:0 Wr~jBuburg ax97914133 p. 7 00 c-i According to a preferred feature of the invention there are a plurality of first 3 orifices each of a differing diamerters and dimensioned according to desired flow rate required for the respective discharge state, each orifice associates with a (N different discharging position of the first member.

According to a preferred feature of the invention the first member is associated IND with a bearing member which is received between the first member and the o discharge nozzle, the bearing member being rotatable within the first member but being fixed relative to the body, wherein outlet is located within a chamber

IN

o defined within the bearing member said chamber having a duct which opens to the exterior of the bearing member, said at least one orifice communicating with the duct on said rotation of the first member to the respective discharging position.

According to a preferred feature of the invention the duct is radially disposed relative to the central axis.

According to a preferred feature of the invention the body is adapted to be sealingly fixed into an opening in the wall of a closure plug which is inflatable, wherein the first member is located to the exterior of the closure plug and the at least one first orifices open into the interior of the closure plug, According to a preferred feature of the invention the body has an annular flange which is intended in use to be fixed to the portion of the wall surrounding the opening.

According to a preferred feature of the invention the body is generally tubular and the first member is concentrically received wvithin the body.

According to another aspect the invention resides in an aerosol canister for inflation of a borehole plug having a control mechanism of the form as claimed at any one of the preceding claims applied thereto and positioned to cooperate with the discharge nozzle.

COMS ID No: ARCS-199474 Received by IP Australia: Time 18:15 Date 2008-07-23 23 Jul 2000 17:02 Wray Eunburyj Fax 97914133 p.8 00 According to another aspect the invention resides in an inflatable borehole plug Z containing a canister of the form as described above wherein the at least one first orifice opens into the interior of the borehole plug.

According to another aspect the invention resides in an inflatable borehole plug containing an aerosol canister having an aerosol canister control mechanism of NO the form as described above mounted to it, said aerosol canister control O mechanism mounted to the wall of the borehole plug wherein the at least one O first orifice opens into the interior of the borehole plug and the first member is to othe exterior of the borehole plug..

The invention will be more fully understood in the light of the following description of several specific embodiments.

Brief Description of the Drawings Embodiments of the present invention will now be described with reference to the accompanying drawings wherein: Figure 1 is a sectioned side view of a valve control mechanism according to a first preferred embediment of the invention shown in a first deactivated state, Figure 2A is a sectioned view of a typical aerosol gas release valve, Figure 2 is a part sectioned end view of the valve control mechanism of Fig. 1, Figure 3 is a further view of the valve control mechanism of Fig 1 shown in a second activated state.

Figure 4 is a part sectioned side view of a valve control mechanism according to a second preferred embodiment of the invention shown in a first non-activated state, COMS ID No: ARCS-199474 Received by IP Australia: Time 18:15 Date 2008-07-23 23 Jul 2000 17:02 Wrayj Bunburyd Fax 97914133 p.9 00 o-6- C Figure 5 is a further view of the valve control mechanism of Pig. 4 shown in a Z second activated state, 1, A Figures 6A to 6C show forms of a discharge valve component of the second preferred embodiment.

V. 5 Figure 7 is a sectioned side view of a further example of a valve control o mechanism according to the first preferred embodiment when in a non- O discharging state, cA Figure 7A is a sectioned end view of the valve control mechanism of Fig.

7,Figure 8 is a sectioned side view of the valve control mechanism of Figs. 7 and 7A when in a discharging state, Figure 9 is a perspective view of the valve control mechanism of Figs. 7, 7A and 8, Figure 10 is a first side view of a further preferred embodiment of a valve control mechanism according to the invention, Figure 11 is a second side view of the valve control mechanism of Fig. Figure 12 is a part sectioned view of the valve control mechanism of Figs. 10 and 11 when in a non-discharging state with a first one of a plurality of discharge rates selected, Figure 13 is a part sectioned view of the valve control mechanism of Figs. 10 and 11 when in a non-discharging state with a second one of a plurality of discharge rates selected, Figure 14 is a part sectioned view of the valve control mechanism of Figs. 10 and 11 when in a discharging state.

Detailed Description of Preferred Embodiments COMS ID No: ARCS-199474 Received by IP Australia: Time 18:15 Date 2008-07-23 23 Jul 2008 17:03 Wras Bunburj Fax 97914133 00 -7o CFirst Preferred Embodiment With reference to Figs 1 and 2, in a first preferred embodiment of the invention a Cvalve system 10 comprises a support structure 12 in the form of a hollow cap attached to the upper rim of an aerosol canister 14. Aerosol canister 14 in this embodiment is provided with a standard aerosol gas release valve 16, retained in Ithe end wall 17 of canister 14.

O

IRelease valve 16, as shown in Fig. 1A, comprises a generally cylindrical, partially ohollow nozzle 18, open at its upper end 20, and urged upwardly into a limiting position by a spring 22 when in a deactivated state. When nozzle 18 is depressed vertically downwards, an orifice 19 passes below the level of seal 23 thereby allowing pressurized gas 24 to pass through orifice 19 and eject from open end Referring again to Figs, 1 and 2, support structure 12 li3 adapted to retain a sliding control member 26 and an intermediate member 25 in pairs of opposing slots 11 and 13 respectively in the sides of support structure 12. Intermediate member 25 and sliding control member 26 are disposed at right angles one to the other and normal to the axis of canister 14. They are so arranged that sliding control member 26 slides over the upper surface 28 of the intermediate member and conversely, so that intermediate member 25 may slide under sliding control member 26, as indicated by arrow A and B in Figs 1 and 2 respectively.

Intermediate member 25 and sliding control member 26 are biased upwardly, for example by a spring (not shown), so that the lower surface of intermediate member 25 is just clear of nozzle 18; the upward movement of sliding control member 26 being limited by the upper limits of slots 11.

As best seen in Fig. 2, intermediate member 25 comprises an elongate bar provided with a plurality of orifices, three in the example of Fig. 2) 27A, 27D and 27C, each of which is adapted to engage with the outer end 20 of nozzle 16 but which have a gradation of outlet openings in the upper surface 28 of intermediate member 25. Each gradated opening of orifices 27A to 27C may be calibrated for a desired rate of flow and length of time of exhaustion of gas from canister Ils.

COMS ID No: ARCS-199474 Received by IP Australia: Time 18:15 Date 2008-07-23 23 Jul 2000 17:03 Wra j Bunbur!j Fax 23 ul200 1:03 Wr~j unur~ Fx714133 P.11 0 (N intermediate member 25 may be slid laterally to select any one of the three SZ orifices 27A to 1 7C to align with nozzle 18. Positive locations may be provided, for example by detent. grooves (not shown) in upper surface 28 of sliding control member 25, adapted to engage With a suitable projection downwardly (not shown) from sliding control member 26.

IND As best seen in Fig. 1, sliding control member 26 is provided with 'wedge o formations 30A and 30B, rising from a first lower level to an upper' level, at which IND detent areas are provided with detent notches 31A and 31B along the upper o edges. Detent notches 31A and 31B are arranged to retain said sliding control member 26 in the position shown in Fig. 3..

Comparing now Figs. I and 3, it will be understood that when sliding control member 25 is driven from the position shown in Fig. 1 in the direction of arrow A to that shown in Fig. 3, its underside is progressively driven downwardly and consequently, intermediate member 25 will be driven downwardly to firstly engage and then depress nozzle 18 thus releasing gas 24 from canister 14.

Sliding control member 26* is provided with orifice 34 arranged, such that when detent formations 31A and 31}3 engage the upper edges of slots 11 of support structure 12, as shown in Pig. 3, orifice 34 is aligned with the selected orifice 27A, B orC.

A further example of a valve control mechanism according to this first preferred embodiment is shown in Figs. 7, 8 and S in which like features are numbered alike, and in which the support structure 12 comprises a base ring 40 with opposing pairs of vertical posts, each pair bridged by a cross member 42 and 4 respectively, to provide opposing slots 11 analogous to the slots 11 depicted in Figs. I and 3.

Second Preferred Embodiment With reference to Figs. 4 and 5, a support structure 112 is similarly attached to the upper rim of an aerosol canister 11.4. A control member 126 is slidably retained in support structure 112, passing through slots 111A and 111 B.The COMS ID No: ARCS-199474 Received by IP Australia: Time 18:15 Date 2008-07-23 23 Jul 2000 17:04 Wra j DunburH Fax 23 ul208 7:4 ra~ funurj ax97814133 p. 12 00 CAunderside of control member 126 is provided with a wedge structure 128 Z arranged so that when control member 126 is driven from the position shown in Fig. 4 to that shown in Fig. 5, wedge structure 128 causes discharge nozzle 118 to be depressed vertically downward.

The upper side of control member 126 is provided with a. plurality of detent IND grooves 131 for engagement with the upper inside edge of slot 111. By this o means, control member 126 and wedge structure 128, may be retained against IND the spring -biasing of nozzle lieu at any degree of depression of nozzle 118 o within the range provided by the form of wedge structure i28.

Control member 1.26 is further provided with elongate slot 130 arranged so that when wedge structure 128 depresses nozzle 118 sufficient for gas to flow from canister 114, the gas will pass through slot 130 and. thence through aperture 132 in support structure 112.

Aerosol canister 114 is in this embodiment provided with a modified nozzle 118 according to one of the preferred forms shown in Figs. 6A to 6C. In contrast to the typical valve nozzle described in the first preferred embodiment above, nozzle 1.18 is provided with at least one orifice which allows a rate of gas to pass from the canister depending on the degree of depression of the nozzle 118 relative to seal 123.1n a first preferred form of the orifice shown in Fig. 8A, an array of small holes 119 is arranged in a vertical line in the wall of nozzle 118.

The further nozzle 118 is then depressed relative to seal 123, the more holes wAil be available to pass gas 124 from the canister 114. It will be clear that the holes need not be all the same size, for example increasing in size from the smaller at the bottom of the array to the larger at the top, so that the flow of gas increases exponenially with depression of the nozzle.

In a further preferred form, the orifice in the wall of nozzle 118 may be in the form of a slot 120 as shown in Fig. 603. The flow of gas thus increases with the length of slot exposed to gas 124 below seal 123.

COMS ID No: ARCS-199474 Received by IP Australia: Time 18:15 Date 2008-07-23 23 Jul 2008 17:04 Wra~j Bunburtj Fax 97914133 p.13 00 (N In yet a further preferred form, the orifices may again take the form of small holes 3Z 119 but in this example arranged in a spiral formation as shown in Fig. 6C. This fonrnation allows for an increasing flow of gas for relatively small depressions of nozzle 118 Third Preferred Embodiment

IND

o With reference to Figs. 10 to 14 in a further embodiment of the invention, a valve control mechanism 200 is adapted for fixing into an opening 210 in the wall of the 0N borehole plug 212 (shown partially in Figs. 10 and 11) so that discharge of a CA pressurised gas from a canister 214 is discharged within the plug 212 from one of a plurality of discharge orifices 216 at a desired a discharge flow rate. In addition the operation of the valve mechanism of the canister 2i4 is effected through the discharge control member 218 which is supported to be exterior of the plug 212.

As shown in Figs. 10 and li the opening 210 in the wall of the plug 212 receives a tubular body 222 which is provided with peripheral flange 220 which is to the wall 212. As best seen in the sectioned side view of Fig. I A, integrally the tubular body includes a cylindrical housing 224. Two support posts 226 and 228 extend from the underside of flange 220 and integrally connect the flange 220 to a ring base 230 which in turn is adapted for snap-on attachment to the upper rim of an aerosol canister 214.

The ring base 230 is flexibly connected, to a central discharge member 232 a radial array of flexible elements (not shown) or like means. The central discharge member 232 is seated on the discharge nozzle 234 of the canister 214.

The discharge selection control member 218 is rotatably mounted within the housing 224 of the tubular member 220, with its axis of rotation being coaxial with discharge nozzle 234. The lower end of the discharge selection control member 218 is formed with an annular skirt 242 which is received over a central discharge member 232, and is supported such that it is able to rotate about the COMS ID No: ARCS-199474 Received by IP Australia: Time 18:15 Date 2008-07-23 23 Jul 2000 17:04 Wra j Bunbur!j Fax 23 ul208 7:4 rag unurj ax97914133 p.14 0 (N central discharge member 232 which is prevented from rotation relative to the 3Z ring base by its connection to ring base 230 through the radial array of flexible elements. The control member 218 is mounted to be capable of for axial slidable movement within the housing 224.

The central discharge member 232 has a central bore 235 which is received over IND the discharge nozzle 234. The central bore is formed with an upper extension o 236 which ids offset from the central axis of the bore The central discharge member 232 also has a radial passage 238 which extends between the o extension 236 and an exit recess 240 at the outer face of central discharge member 232.

The lower skirt 242 of the discharge control member 218 is provided with at least two, but preferably three graded sized orifices 216A, 216B and 216C arranged at degree intervals around skirt 214 and at a position such that on rotation of the discharge control member one of the orifices can be sequentially aligned with the exit recess 240 It is the size of a particularly selected orifice 216A to 216C determines the discharge flow rate from canister 214 into the borehole plug 212 once discharge nozzle 234 has been activated. In this regard both the selection of a discharge rate and the activation of discharge nozzle 234 can both be effected by manipulation of the discharge control member 218. To control the rate of discharge the control member 218 can be rotated to bring a particular orifice into alignment with recess 240 (as shown in the views of Figs. 12 and 13). To deactivate discharge nozzle is effected by causing inward slidable movement of the of the discharge control member within the tubular body 222 which will through the central discharge member 232, force the discharge nozzle 234 into a discharging state. To facilitate manipulation of the discharge control member 218 its outer axial face is provided with a laminar finger grip 250.

The discharge control member 218 is further associated with a locking means (not shown) which is able to retain the discharge control member 218 in the depressed condition at which it will allow the discharge of the contents of the COMS ID No: ARCS-199474 Received by IP Australia: Time 18:15 Date 2008-07-23 23 Jul 2008 17:05 Wra j Bunbur j Fax 97914133 00 0 -12- 0 N canister through the extension 236 of the central bore, the radial passage 238, Z the recess 238 and one of the orifices 216. The locking means may comprise, for example a bayonet arrangement whereby on depression of the discharge Ncontrol member to the discharging state and the rotation of the discharge control member 218 to the desired discharge state to bring the desired orifice into alignment with the recess causes the discharge control member 218 to be N retained at that position.

0 N In Use (In use, the control mechanism of any one of the above described embodiments is attached to the canister which is contained within or fixed to the borehole plug (not shown). Prior to lowering the plug into a. borehole, the mechanism of the present invention can be manipulated through the flexible sides of the still deflated bag of the plug, or in the case of the Third Embodiment activated from the outside of the plug.

in the first embodiment described above, a user selects an appropriate orifice of intermediate member 25 for alignment with the discharge nozzle 18, and drives sliding control member 26 to the detent position.

For the second embodiment, a user drives the control member to a desired detent position within the range of detent positions provided.

For the third embodiment the control member is caused to rotate to the selected discharge orifice position and simultaneously depressed to lock the mechanism into a discharge state.

In each case the plug is then lowered into the borehole. The retention of the control member in the discharging state ensures that the discharge nozzle remains depressed so that discharge from the canister continues until it is exhausted.

Selection of a discharge rate may be made with reference to a guide chart, for COMS ID No: ARCS-199474 Received by IP Australia: Time 18:15 Date 2008-07-23 23 Jul 2000 17:05 Wrayj Bunburm Fax 97914133 p.16 00 0 -13- ClN example where input parameters may for example include characteristics of the 3 borehole and borehole plug, the estimated lowering time and ambient temperature.

The above describes only some embodiments of the present invention and modifications, obvious to those skilled in the art, can be made thereto without ND departing from the scope and spirit of the present invention.

0 0 0 ci COMS ID No: ARCS-199474 Received by IP Australia: Time 18:15 Date 2008-07-23

Claims (18)

1. An aerosol canister control mechanism for inflation of a borehole plug; said IC aerosol canister having one end upon which the control mechanism is in use to be mounted, the one end having a discharge nozzle, the discharge nozzle 0 having an outlet, the discharge nozzle associated with a valve, whereby o displacement of the discharge nozzle to a discharging state will open the valve oto permit the contents of the canister to escape through the oullet, said control ci mechanism comprising a body which is adapted to be mounted to the one end, the control mechanism further comprising a first member supported by the body for axial slidable movement wherein in use the first member is positioned to be generally coaxial with to the canister and the discharge nozzle and the slidable movement of the first member is generally parallel to the central axis of the canister, wherein in use on the body being supported on the one end the first member is axially movable between a first position at which the discharge nozzle is closed and a second position at which the first member has caused said displacement of the discharge nozzle, the first member adapted to cooperate with the outlet to receive the contents of the canister when the discharge nozzle has been displaced, the first member further supported from the body to be rotatable about its central axis, the first member being formed with at least one first orifice positioned to be capable of being aligned to be able to communicate with the outlet on said rotation of the first member to a discharging position, a first retention means provided between the first member and the body adapted to retain the first member in its discharging position.

2. An aerosol canister control mechanism as claimed at claim 1 wherein the first member is biased to its first position.

3. An aerosol canister control mechanism as claimed at claim 1 or 2 wherein there are a plurality of first orifices each of a differing diameters and COMS ID No: ARCS-199474 Received by IP Australia: Time 18:15 Date 2008-07-23 23 Jul 2008 17:06 Wra j Bunbur!j Fax 23 ul200 1:0 Wr~jBuburj ax97814133 0 (N dimensioned according to desired flow rate required for the respective 3Z discharge state, each orifice associates with a different discharging position of the first member.

4. An aerosol canister control mechanism as claimed at claim 1 or 2 or 3 wherein the first member is associated with a bearing member which is received IND between the first member and the discharge nozzle, the bearing member o being rotatable within the first member but being fixed relative to the body, IND wherein outlet is located within a chamber defined within the bearing member o said chamber having a duct which opens to the exterior of the bearing member, said at least one orifice communicating with the duct on said rotation of the first member to the respective discharging position.

An aerosol canister control mechanism as claimed at claim 4 wherein the duct is radially disposed relative to the central axis.

6. An aerosol canister control mechanism as claimed at any one of the preceding claims wherein the body is adapted to be sealingly fixed into an opening in the wall of a closure plug which is inflatable, wherein the first member is located to the exterior of the closure plug and the at least one first orifices open into the interior of the closure plug,

7. An aemosol canister control mechanism as claimed at claim 6 wherein the body has an annular flange which is intended in use to be fixed to the portion of the wall surrounding the opening.

8. An aerosol canister control mechanism as claimed at claim 1 wherein the body is generally tubular and the first member is concentrically received within the body.

9. An aerosol canister control mechanism substantially as herein described with reference to Figures 10 to 14 of the accompanying drawings. COMS ID No: ARCS-199474 Received by IP Australia: Time 18:15 Date 2008-07-23 23 Jul 2008 17:06 Wrat Bunburu Fax 97914133 p.19 00 o -16- 0 N

10.An aerosol canister for inflation of a borehole plug having a control Z mechanism of the form as claimed at any one of the preceding claims applied thereto and positioned to cooperate with the discharge nozzle.

11.An inflatable borehole plug containing a canister of the form as claimed at N 5 claim 10 wherein the at least one first orifice opens into the interior of the NO borehole plug. O I

12.An inflatable borehole plug containing an aerosol canister having an aerosol ocanister control mechanism of the form as claimed at claim 6 or 7 mounted to it, said aerosol canister control mechanism mounted to the wall of the borehole plug wherein the at least one first orifice opens into the interior of the borehole plug.

13.A borehole plug comprising an inflatable bladder an aerosol canister control mechanism sealingly fixed into the wall of the bladder, said aerosol canister control mechanism comprising a body which is mounted to one end, of an aerosol canister located within the bladder, the one end having a discharge nozzle, the discharge nozzle having an outlet, the discharge nozzle associated with a valve, whereby displacement of the discharge nozzle to a discharging state will open the valve to permit the contents of the canister to escape through the outlet into the interior of the bladder, the control mechanism having an activation means located to the exterior of the bladder, said activation means being adapted to cause said displacement of the discharge nozzle and to retain the discharge nozzle in the displaced state.

14.A borehole plug as claimed at claim 11 wherein the control mechanism is adapted to cause the discharge nozzle to deliver at differing rates.

15.A borehole plug as claimed at claim 11 or 12 wherein the control mechanism comprises an annular flange which is fixed to the region of the wall of the bladder surrounding an opening in which the control mechanism is received. COMS ID No: ARCS-199474 Received by IP Australia: Time 18:15 Date 2008-07-23 23 Jul 2008 17:OG Wra j Elunbur j Fax 23 ul208 1:0 Wa~Hunurj ax97814133 0 (N

16.A borehole plug as claimed at any one of claims 11 to 13 wherein said control 3Z mechanism comprising a body which is adapted to be mounted to the one end, the activation means comprising a first member supported by the body CA for axial slidable movement, wherein in use the first member is positioned to be generally coaxial with to the canister and the discharge nozzle and the slidable movement of the first member is generally parallel to the central axis IND of the discharge nozzle to the canister, wherein in use on the body being o supported on the one end the first member is axially movable between a first position at which the discharge nozzle is closed and a second position at which the first member has caused said displacement of the discharge, the first member further supported from the body to be rotatable about its central axis, the first member adapted to cooperate with the outlet to receive the contents of the canister when the discharge nozzle has been displaced, the first member being formed with at least one first orifice positioned to be capable of being aligned to be able to communicate with the outlet on said rotation of the first member, a first retention means provided between the first member and the body adapted to retain the first member in its first position and when the at least one first orifice is aligned with the outlet,.

17.A borehole plug as claimed at claim 14 wherein the first member is biased to its first position.

18.A borehole plug as claimed at claim 14 or 15 wherein there are a plurality of first orifices each of a differing diameters and dimensioned according to desired flow rate required for the respective discharge state. 19S.A borehole plug as claimed at claim 14 or 15 or 18 wherein the first member is associated with a bearing member which is received between the first member and the discharge nozzle, the bearing member being rotatable within the first member but being fixed relative to the body, wherein outlet is located within a chamber defined within the bearing member said chamber having a duct which opens to the exterior of the bearing member,, said at least one orifice communicating with the duct on said rotation of the first member. COMS ID No: ARCS-199474 Received by IP Australia: Time (I-Pm) 18:15 Date 2008-07-23 23 Jul 2008 17:07 Wray Eunburyj Fax 97914133 p. 2 1 0 -18- 0 18 (N 20.A borehole plug as claimed at claim 17 wherein the duct is radially disposed Z relative to the central axis. (N 21.A borehole plug substantially as herein described with reference to Figures to 14 of the accompanying drawings O (N (N COMS ID No: ARCS-199474 Received by IP Australia: Time 18:15 Date 2008-07-23