AU2005100094B4 - Valve System - Google Patents

Description

P/001009 Regulation 328 AUSTRALIA Patents Act 1990 COMPLETE SPECIFICATION FOR AN INNOVATION PATENT Invention Title: VALVE SYSTEM The invention is described in the following statement together with the best method of performing it known to us: Our Reference: 056001 -2 VALV SYSTEM The present invention relates to valves for aerosol cans and, more particularly, to variable release valves for 5 aerosol cans for the inflation of bore hole plugs. BACKGROUND Typically explosive charges for mining and other excavation activities, are placed in boreholes. Frequently 10 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 15 of the borehole. Typically, inflation is by means of an aerosol canister attached to the bag and arranged so as to discharge its pressurised contents during the descent of the bag down the borehole. 20 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 25 higher than intended. Alternatively, inflation may be so slow that the bag needs to be retained at a desired level - 3 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. 5 BRIEF DESCRIPTION OF INVENTION Accordingly, in a one broad form of the invention there is provided a variable control mechanism for gas flow from an aerosol canister for inflation of a borehole plug; said mechanism comprising a. first member providing variable 10 flow means between a gas retained in said canister and said plug, and a second member arranged to control said first body between a deactivated state and a plurality of activated states. Preferably, said mechanism further comprises a hollow 15 housing sealably engaged with an end of said canister; said housing slidably retaining said first member and said second member. Preferably, said first member is provided with at least three gradated orifices; each respective one of said 20 orifices providing one of said plurality of activated states; and wherein each of said at least three gradated orifices is selectively brought into coincidence with an outlet nozzle of said canister by sliding movement of said first member.

-4 Preferably, said second member is provided with cam structures adapted to provide downwardly compressive force to said first member, when said second member is slid from said deactivated state to an activated state, so as to 5 cause said first member to depress said outlet nozzle of said canister; thereby releasing said gas retained in said canister to pass through one of said at least three gradated orifices. Preferably, said second member is provided with an 10 orifice; said orifice arranged to coincide with one of said at least three gradated orifices of said first member in coincidence with said outlet nozzle, when said second member is in said activated state. Preferably, said first member and said second member 15 comprise generally elongate bodies slidably retained in respective pairs of opposite slots in said housing; said second member overlying said first member, and wherein said first member and said second member are disposed at right angles one to another. 20 Preferably, said first member is urged upwardly by resilient means against an underside of said second member such that upper surfaces of said second member are in contact with upper limits of said respective pairs of opposite slots retaining said second member.

-5 Preferably, said upper surfaces of said second member comprise a pair of upwardly projecting wedge shaped structures; each said wedge shaped structure rising to a plateau provided with a detent notch; said wedge shaped 5 structures and said detent notches spaced apart so as to engage with said upper limits of said respective pair of opposite slots retaining said second member when said second member is urged longitudinally from a said deactivated state to a said activated state. 10 Preferably, when said second member is slid longitudinally through said respective pair of opposite slots from said deactivated state to said activated state, said wedge shaped structures force said second member and said first member downwardly, such that said first member 15 engages and depresses said outlet nozzle so as to release said gas from said canister; said activated state maintained by engagement of said notches with said pair of opposite slots. In a further broad form of the invention there is 20 provided a variable control mechanism for gas flow from an aerosol canister for inflation of a borehole plug; said mechanism comprising a first member providing variable flow means between a gas retained in said canister and said plug, and a second member arranged to control said first - 6 body between a deactivated state and a plurality of activated states. Preferably, said mechanism further comprises a hollow housing sealably engaged with an end of said canister; said 5 housing slidably retaining said second member in a pair of opposing slots. Preferably, said first member comprises a generally cylindrical, partially hollow body closed at a lower end and open at an upper end; said body arranged for sliding 10 reciprocal motion through a sealing member in an end wall of said canister; said first member urged outwardly to a limiting position by resilient means when said first member is in said deactivated state. Preferably, said first member is provided with at 15 least one orifice in a wall of said partially hollow body; said at least one orifice positioned at a point preventing passage of gas from said canister through said at least one orifice when said first member is in said deactivated state. 20 Preferably, at least a proportion of said at least one orifice is exposed to said gas in said canister when said first member is urged inwardly from said deactivated state to said activated state; said variable flow of said gas from said canister a function of said proportion of said at least one orifice. Preferably, said at least one orifice comprises a slot aligned with said axis of said generally cylindrical, 5 partially hollow body. Preferably, said at least one orifice comprises a series of holes arranged in a line and aligned with said axis of said generally cylindrical, partially hollow body. Preferably, said at least one orifice comprises a 10 series of holes arranged as a portion of a helix. Preferably, said second member is provided along an underside of said member with a wedge shaped structure; said wedge shaped structure adapted to engage and depress said first member when said second member is urged to slide 15 longitudinally through said pair of opposing slots. Preferably, a portion of an upper surface of said second member is provided with a plurality of detent grooves adapted to engage with an upper limit of one of said pair of opposing slots so as to maintain a selected 20 degree of inward urging of said first member. In yet a further broad form of the invention there is provided a method for controlling a rate of inflation of a bore hole plug by control of a flow of gas from a canister attached to said plug; said method including the steps of: (a) determining the depth at which said bore hole plug is to be situated within said bore hole, 5 (b) estimating a time required for lowering said plug to said depth, (c) selecting a setting of a flow rate control mechanism attached to said canister. Preferably, said control mechanism comprises a first 10 member providing variable flow means between a gas retained in said canister and said plug, and a second member arranged to control said first body between a deactivated state and a plurality of activated states. 15 BRIEF DESCRIPTION OF DRAWINGS Embodiments of the present invention will now be described with reference to the accompanying drawings wherein: Figure 1 is a part sectioned side view of a valve 20 system according to a first preferred embodiment of the invention shown in a first deactivated state, Figure 1A is a sectioned view of a typical aerosol gas release valve, Figure 2 is a part sectioned end view of the valve system of Fig. 1, Figure 3 is a further view of the valve system of Fig. 1 shown in a second activated state. 5 Figure 4 is a part sectioned side view of a valve system according to a second preferred embodiment of the invention shown in a first non-activated state, Figure 5 i.s a further view of the valve system of Fig. 4 shown in a second activated state, 10 Figures 6A to 6C show forms of a valve component of the second preferred embodiment. DETAILED DESCRIPTION OF PREFERRED EMODIMlENTS 15 First Preferred Embodiment With reference to Figs. 1 and 2, in a first preferred embodiment of the invention a valve system 10 comprises a housing 12 sealably engaged to the top of an aerosol canister 14. Aerosol canister 14 in this embodiment is 20 provided with a standard aerosol gas release valve 16, retained in the end wall 17 of canister 14. Release valve 16, as shown in Fig. 1A, comprises a generally cylindrical, partially hollow nozzle 18, open at its upper end 20, urged upwardly into a limiting position 25 by a spring 22 when in a deactivated state. When nozzle 18 is depressed vertically downwards, an orifice 19 passes - 10 below the level of seal 23 thereby allowing pressurized gas 24 to pass through orifice 19 and eject from open end 20. Referring again to Figs. 1 and 2, housing 12 is adapted to retain first and second sliding members 25 and 5 26 in pairs of opposing slots 11 and 13 respectively. First member 25 and second member 26 are disposed at right angles one to the other and arranged so that second member 26 slides over the upper surface 28 of the first member 25, and conversely, so that the first member 25 may slide under 10 second member 26, as indicated by arrow A and B in Figs. 1 and 2 respectively. First and second members 25 and 26 are biased upwardly, for example by a spring (not shown), so that the lower surface of first member 25 is just clear of nozzle 18; the upward movement of second member 26 being 15 limited by the upper limits of slots 11. As best seen in Fig. 2, first member 25 is provided with a plurality of orifices, three in the example of Fig. 2) 27A, 27B and 27C, each of which is adapted to engage with the outer end 20 of nozzle 18 but which have a 20 gradation of outlet openings in the upper surface 28 of first 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 18. First member 25 may be slid laterally to select any one of the three 25 orifices 27A to 17C to align with nozzle 18. Positive locations may be provided, for example by detent grooves -- 11 - (not shown) in upper surface 28 of second member 25, adapted to engage with a suitable projection downwardly (not shown) from second member 26. As best seer. in Fig. 1, second member 26 is provided 5 with wedge formations 30A and 30SB, leading up to plateaus provided with decent notches 31A and 31B along its upper edge. Comparing now Figs. 1 and 3, it will be understood that when second member 26 is driven from the position shown in Fig. 1 in the direction of arrow A to that shown 10 in Fig. 3, first member 25 will be driven downwardly to firstly engage and then depress nozzle 18 thus releasing gas 24 from canister 14. Second member 26 is provided with orifice 34 arranged such that when detent formations 31A and 31B engage the wall sections of housing 12, as shown in 15 Fig. 3, orifice 34 is aligned with the selected orifice 27A, B or C. Second Preferred 1mbodiment With reference to Figs. 4 and 5, a housing 112 is again sealably engaged to the upper end of an aerosol 20 canister 114. A control member 126 is slidably retained in housing 112, passing through slots 1I1A and 111B. The underside of control member 126 is provided with a wedge structure 128 arranged so that when control member 126 is driven from the position shown in Fig. 4 to that 25 shown in Fig. 5, wedge structure 128 causes nozzle 118 to be depressed vertically downward.

- 12 The upper side of control member 126 is provided with a plurality of detent grooves 131 for engagement with the upper inside edge of slot 111A. By this means, control member 126 and wedge structure 128, may be retained against 5 the spring biasing of nozzle 118, at any degree of depression of nozzle 118 within the range provided by the form of wedge structure 128. CQntrol member 126 is further provided with elongate slot 130 arranged so that when wedge structure 128 10 depresses nozzle 118 sufficient for gas to flow from canister 114, the gas will pass through slot 130 and thence through aperture 132 in housing 112. Aerosol canister 114 is in this embodiment provided with a modified nozzle 118 according to one of the 15 preferred forms shown in Figs. 6A to 6C. In contrast to the typical valve nozzle described in the first preferred embodiment above, nozzle 118 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 20 nozzle 118 relative to seal 123. In a first preferred form of the orifice shown in Fig. 6A, 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 will be available to pass gas 124 25 from the canister 114. It will be clear that the holes need not be all the same size, for example increasing in size - 13 from the smaller at the bottom of the array to the larger at the top so that the flow of gas increases exponentially with depression of the nozzle. In a further preferred form, the orifice in the wall 5 of nozzle 118 may be in the form of a slot 120 as shown in Fig. 6B. The flow of gas thus increases with the length of slot exposed to gas 124 below seal 123. In yet a further preferred form, the orifices may again take the form of small holes 119 but in this example 10 arranged in a spiral formation as shown in Fig. 6C. This formation allows for an increasing flow of gas for relatively small depressions of nozzle 118. In Use In use, housing 12 (or 112) is attached to the 15 canister which is contained within the borehole plug (not shown). In the first embodiment described above, a user then selects an appropriate orifice of first member 25 for alignment with nozzle, 18, and drives second member 26 to the detent position. For the second embodiment, a user 20 drives the control member to a desired detent position. In each case the plug is then lowered into the borehole. The selection may be made with reference to a guide chart, for example where input arguments may include characteristics of the borehole, the estimated lowering 25 time and ambient temperature.

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

Claims (5)

1. A variable control mechanism for gas flow from an aerosol canister for inflation of a borehole plug; said mechanism comprising a first member providing 5 variable flow means between a gas retained in said canister and said plug, and a second member arranged to control said first body between a deactivated state and a plurality of activated states

2. The mechanism of claim 1 wherein said mechanism 10 further comprises a hollow housing sealably engaged with an end of said canister; said housing slidably retaining said first member and said second member.

3. The mechanism of claim 1 or 2 wherein said first member is provided with at least three gradated 15 orifices; each respective one of said orifices providing one of said plurality of activated states; and wherein each of said at least three gradated orifices is selectively brought into coincidence with an outlet nozzle of said canister by sliding movement 20 of said first member.

4. The mechanism of claim 3 wherein said second member is provided with cam structures adapted to provide downwardly compressive force to said first member, when said second member is slid from said deactivated - 16 state to an activated state, so as to cause said first member to depress said outlet nozzle of said canister; thereby releasing said gas retained in said canister to pass through one of said at least three gradated 5 orifices.

5. The mechanism of claim 3 or 4 wherein said second member is provided with an orifice; said orifice arranged to coincide with one of said at least three gradated orifices of said first member in coincidence 10 with said outlet nozzle, when said second member is in said activated state. DATED: 1. February 2005 15 MDORE MNAQMiNT PARTNERSHIP PTY LIMITED MTI PRODUCTS PTY LTD by their Patent Attorneys: WALLINGTON-DUMM!!R 20