AU2007216888B2 - Valve Control Mechanism for Aerosol Canister - Google Patents

Description

Regulation 3.2 ORIGINAL AUSTRALIA Patents Act 1990 PROVISIONAL SPECIFICATION Invention Title: VALVE CONTROL MECHANISM FOR AEROSOL CANISTER The invention is described in the following statement: 1 -2 VALVE CONTROL MECHANISM FOR AEROSOL CANISTER FIELD OF INVENTION The present invention relates to valves for aerosol cans. A particular application of the invention relates to valves for aerosol cans for the 5 inflation of borehole plugs, however the invention is not restricted in its scope to such an application. BACKGROUND Typically explosive charges for mining and other excavation activities, are placed in boreholes. Frequently such charges are supported at some point 10 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. Examples of arrangements that have been proposed in the past as disclosed in patent specifications AU199230436, AU199893295, 15 AU200010114 and AU200111113, In some cases, inflation is by means of an aerosol canister connected into or located in the bag and arranged so as to discharge its pressurised contents during the descent of the bag down the borehole. One form of valve control that has been proposed in the past is disclosed in AU200126422. The arrangement 20 disclosed in the specification relies upon the use of a latchable valve actuator which is resiliently defornable to enable engagement with a latch member to engage and retain the valve of an aerosol can in the open position. The difficulty with this arrangement is that the actuator is formed of a plastics material the resilient characteristics of which are temperature sensitive. In use 25 the actuator will be subjected to significant extremes of ambient temperature. Under hot conditions the resilience of the plastic weakens which affects the capacity of the watchable member to remain in the latched condition while under -3 cold conditions the degree of resilience is affected such that the latchable actuator become brittle and rather that being resiliently deformed it will break or crack. A common problem experienced with such arrangements is that in some 5 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 10 an object of the present invention to address or at least ameliorate some of the above disadvantages. The discussion throughout this specification, of the background and prior art to the invention is intended only to facilitate an understanding of the present invention. - It should be appreciated that the discussion is not an 15 acknowledgement or admission that any of the material referred to was part of the common general knowledge in Australia and the world as at the priority date of the application. BRIEF DESCRIPTION OF INVENTION Throughout the specification, unless the context requires otherwise, the word 20 "comprise" or variations such as "comprises" or "comprising", will be understood to imply the incluion of a stated integer or group of integers but not the exclusion of any other integer or group of Integers. According to one aspect the invention resides in an aerosol canister control mechanism for Inflation of a borehole plug; said aerosol canister having one end 25 upon which the control mechanism is to be mounted in use, the one end having a discharge nozzle mounted to the upper end, the discharge nozzle associated with a valve which is biased to a closed position, the discharge nozzle having an outlet, whereby displacement of the discharge nozzle in a direction towards the one end to a discharging state will open the valve to permit the contents of the -4 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 control member mounted to the body for slidable movement wherein in use the control member is positioned to be transverse to 5 the to the canister and the slidable movement of the control member is transverse to the canister, the control member being slidable between a retracted position at which it is not engaged with the discharge nozzle to cause the valve to open and a discharging position at which it is in engagement with the discharge nozzle to displace said discharge nozzle and cause the discharge 10 nozzle to adopt the discharging state, the control member being retained in the body by a retaining means which is able to retain the control member in either the retracted position or the discharging position. According to a preferred feature of the invention the one end has a rim surrounding the discharge nozzle and the body is configured to be able to be 15 attached to the rim to at least partially surround the discharge nozzle. According to a preferred feature of the invention said body comprises a hollow body formed as a cap-like element which is intended in use to be attached to said rim of said canister. According to a preferred feature of the invention said control member is 20 provided with a wedge formation having an inclined leading face rising from a first lower level to raised level; and an intermediate face which is an extension of the leading edge but Is generally parallel to the direction of slidable movement, the intermediate face having at least one first engagement element along its length, the body having at least one second engagement element, said 25 first and second engagement elements being inter-engagable to resist relative movement between the control member and the body. According to a preferred feature of the invention the inter-engagement between first and second engagement elements permits said slidable movement in a direction away from the retracted position only.

According to a preferred feature of the invention the control member is provided with a bearing surface which is adapted to slidably engage with the outer end of the discharge nozzle, the bearing surface having at least one portion positioned to be engaged with the discharge nozzle when the control member is at its 5 discharging position to cause said discharge. According to a preferred feature of the invention the intermediate face is provided with a single first engagement element. According to a preferred feature of the invention the intermediate face is provided with a plurality of first engagement elements and each first 10 engagement element is associated with one of said portions, the degree of discharge from the nozzle of the valve effected by each portion being different. According to a preferred feature of the invention the engagement of the intermediate face with the body causes relative movement of the bearing surface towards the one end of the canister to cause movement of the 15 discharge nozzle to open the valve. According to a preferred feature of the invention the control member is resiliently urged into contact with the second engagement element. According to a preferred feature of the invention the biasing is effected at least partially by a spring. 20 According to a preferred feature of the invention the biasing is effected at least partially by the biasing applied to the valve.. According to a preferred feature of the invention the discharge nozzle has its outlet at its outer end and the outer end is slidably engaged by the bearing surface and said bearing surface closing the outer end when the control 25 member is in the retracted position, the bearing surface having a single portion having an aperture positioned to cooperate with the discharge nozzle when the -6 portion is located proximate the discharge nozzle to provide a flow path for the fluid flowing from the discharge nozzle. According to a preferred feature of the invention the discharge nozzle has its outlet at its outer end and the outer end is slidably engaged by the bearing surface and 5 said bearing surface closing the outer end when the control member is in the retracted position, each portion having an aperture positioned to cooperate with the discharge nozzle when each portion is located proximate the discharge nozzle to provide a flow path for the fluid flowing from the discharge nozzle, each aperture being dimensioned according to desired flow rate required for the respective 10 discharge state. According to a preferred feature of the invention the bearing surface is defined within an elongate slot shaped recess formed in the control member wherein the longitudinal axis of the slot is parallel to the axis of the control member. According to a preferred feature of the invention the apertures are located at 15 spaced intervals along the recess. According to a preferred feature of the invention said control member is provided with at least two wedge formations, and the body is provided with two sets of second engagement elements wherein the bearing surface is located between the wedge formations. 20 According to a preferred feature of the invention the wedge formation is provided with an end face which is at the end of the intermediate face remote form the leading face, the end face configured to prevent slidable movement of the control member when engaged thereby. According to a preferred feature of the invention a single first engagement element 25 is provided on each wedge formation to cooperate with one second engagement element.

-7 According to a preferred feature of the invention a plurality of first engagement elements are provided on each wedge formation to cooperate with one second engagement element. According to another aspect the invention resides in an aerosol canister for inflation 5 of a borehole plug having a control mechanism of the form as described above applied thereto and positioned to cooperate with the discharge nozzle. The invention will be more fully understood in the light of the following description of several specific embodiment. BRIEF DESCRIPTION OF THE DRAWINGS 10 The description is made with reference to the accompanying drawings of which: Figure 1 is an upper isometric view of a valve control mechanism according to the first embodiment shown in a deactivated state; Figure 2 is a lower isometric view of the body of the valve control mechanism according to the first embodiment with the control in a deactivated state; 15 Figure 3 is an upper isometric view of the control member of the a valve control according to the first embodiment; Figure 4 a lower isometric view of the control member of the a valve control according to the first embodiment; Figure 5 is an isometric view of an aerosol canister with the valve control 20 mechanism according to the first embodiment applied thereto; Figure 6 is a sectional elevation of a of a valve control mechanism according to the second embodiment shown in its deactivated state; Figure 7 is a sectional elevation of a of a valve control mechanism according to the second embodiment shown in its activated state; and -8 Figure 8 is an upper isometric view of a valve control mechanism according to the second embodiment shown in a deactivated state, DETAILED DESCRIPTION OF SPECIFIC EMBODIMENT The first embodiment of the invention as shown at Figures 1 to 5 comprises a 5 valve control mechanism which is intended to be mounted to an aerosol canister to control the discharge from the discharge nozzle. The valve mechanism system comprises a body 12 in the form of a hollow cap which is configured to be able to be rigidly mounted to the upper rim of an aerosol canister 10. The aerosol canister10 in this embodiment is provided with a standard aerosol gas 10 release valve (not shown) retained in the upper end wall of the body of the canister 14. The upper end wall of the canister is provided with a rim (not shown) which surrounds the release valve The release valve comprises a generally tubular nozzle open at its upper end and associated with a valve element accommodated within the end wall which 15 cooperates with a valve seat provided at the outlet of the canister in the upper end wall. The valve and nozzle are urged upwardly into a limiting position by a spring within the canister at which the valve cooperates with the valve seat to close the valve seat and in so doing define a deactivated stale. When the nozzle is depressed downwards against the action of the spring the valve 20 member disengages form the valve seat, thereby allowing the contents of the canister, which comprises a pressurized or liquefied gas or the like, to pass through the open upper end of the nozzle. The body 12 supports a control member 14 which is slidable across the body wherein the slidable movement is to be perpendicular to the discharge nozzle. 25 The body is formed with a skirt 16 having an open face whereby the outer edge of the open face is configured to be able to be fixed to the rim of the aerosol canister to be retained thereby. The inner end of the skirt is provided with a pair of raised portions 18 and 20 which are located at diametrically opposed positions and which are formed with transverse openings which are aligned and 30 are intended to slidably receive the control member. The transverse openings -9 are associated with an inverted channel formation across the interior of body which slid ably receives the control member and the lower edge of each side of the channel is formed with opposed protrusions which serve to retain the control member in position within the body 5 The control member is formed as elongate element which is configured to be receivable in the transverse openings. The outermost end of the control member is formed with a manipulation element 22 which is intended to be engaged by the operator to cause slid able movement of the control member across the body. The engagement of the control member within the transverse openings and the inverted 10 channel is such that the control member is capable of movement towards and away from the open face of the skirt. A suitable biasing means (not shown) is provided between the control member and the body to bias the control member to a position most remote from the open face. As shown at Figure 3 the upper face of the control member is formed with a pair of 15 wedge formations 24 and 26 which are at spaced positions along the control member and which are positioned to be engagable with pawl elements (not shown) on the raised portions 18 and 20 of the body. Each wedge portion is provided with an inclined leading face 28 which extends from a lower position to a raised position, an intermediate face 30 extending from the upper end of the leading face and 20 which is parallel to the axis of the control member and an end face 32 which extends upwardly from the intermediate face. The intermediate face is formed with a pair of notches 34 and 36 at spaced intervals along its length. The pawl elements on the body will be caused to bear on the wedge formations as a result of the resilient biasing between the control member and the body. 25 In use the control member is positioned in the transverse opening in the body such that the pawl elements are engaged with the lower most portions of the leading face 28. For convenience operation of a pawl element of the raised portion 20 will be described in relation to the wedge formations distal from the manipulation element, but it will be appreciated that a pawl element of the raised portion 18 will 30 operate similarly in relation to the wedge formations proximal to the manipulation element. On manipulation of the control member by application of force to the manipulation element 22 the pawl element is caused to move over the leading face -10 and onto the intermediate face 30 and then into engagement with the most adjacent notch 34. With an application of some additional force applied to the manipulation element the pawl element will be forced into engagement with the second notch 36. When at this position the end face 32 is engaged with the body to 5 prevent further displacement of the control member. The notches are configured such that when the pawl element becomes engaged with the notch it is not possible for the control member to return to its earlier position but the control member can be moved into the body. The lower face of the control member is formed with an elongate recess 39. In use 10 the outer end of the nozzle is located with in the recess and will move along the recess with relative movement between the control member and the body. The recess is provided with a pair of apertures 38 and 40 where one aperture 38 is associated with one of the notches 34 and the other aperture 40 is associated with the other notch 36 such that when the pawl element is engaged with a notch the 15 nozzle is aligned with the respective aperture. The apertures are of different diameter. With movement of the control member into the body such that the pawl element engages with the intermediate face 30 and the control member is resiliently displaced towards the end face of the canister and because of the engagement of the bearing face with the nozzle the nozzle is depressed against the 20 biasing action retaining it in the closed position and the release valve is opened. When the pawl element engages with a notch the nozzle is able to discharge through the respective aperture and the rate of discharge is controlled by the dimensions of the respective aperture. In use, the control mechanism of this embodiment is attached to the canister and 25 the canister is located within a closed plastic or like bag (not shown) which is to comprise the borehole plug (not shown). The bore hole plug is intended to block the borehole prior to the insertion of an explosive charge into the borehole to provide a position within the borehole at which the explosive charge is to be located prior to detonation. 30 Prior to lowering the borehole plug into a borehole, the control mechanism of the embodiment is manipulated through the flexible sides of the still deflated -11 bag of the plug to move the control member from the retracted position to the discharge position where one of the apertures is located in alignment with the discharge nozzle. In this regard the user selects an aperture of the control member 14 according to the desired discharge rate. The rate of discharge will govern the 5 rate of inflation of the bag. When the borehole plug is inserted into the borehole it can be allowed to fall freely and the retention of the control member in one of its discharge states ensures that the discharge nozzle remains depressed so that discharge from the canister continues until it is exhausted and the rate of inflation will determine where the bore hole plug will be located within the borehole once 10 inserted into the bore hole. The selection of a discharge rate can be made after reference to a guide chart or the like where the discharge rates are determined form the ambient conditions such as the characteristics of the borehole and ambient temperature. The second embodiment as shown at Figs. 6, 7 and 8, comprises a further 15 preferred embodiment of a valve system for the release of pressurised gas from a canister 214 into a borehole plug (not shown), a discharge control mechanism 200, is attached to the upper rim 211 of the canister 214. The mechanism 200 includes a sliding control member 226 configured in a similar manner to that of control member 14 of the first embodiment described above. The sliding control member 20 226 has a flat underside 227, and an upperside arranged with leading and trailing wedge formations 230a and 230b, rising up to respective leading and trailing detent structures 231 a and 231 b which are provided with detent notches 232a and 232b respectively at their upper edges. The sliding control member 226 is retained in a support structure 212 which is in 25 the form of a cap 212 provided with a pair of slots 237 and 238 at opposite sides of the cap similar to the transverse openings as previously described. As shown in Figs. 6, 7 and 8, the cap 212 may comprises ring base 234 which is configured to be able to be attached to the rim 211 of the canister 214. The cap is provided with opposing pairs of support posts 235 and 236 rising from the ring base 234 where 30 each pair of support posts 235 and 236 is bridged by a cross member 231 and 233 respectively, to provide the slots 237 and 238 through which sliding control - 12 member 226 projects. The slots 237 and 238 are configured to allow sliding movement of sliding control member 226 between a retracted non-discharging state as shown in Fig. 6 and an advanced discharging state as shown in Fig. 7. The leading and trailing wedge formations 230a and 230b are resiliently biased into 5 contact with the cross members 231 and 233 of each of the slots 237 and 238 by the discharge nozzle 218 of the canister through an intermediate member 225 interposed between the nozzle 218 and the flat underside 227 of sliding control member 226. The inherent biasing force of the discharge nozzle will bias the intermediate member 225 against the sliding control member which is then biased 10 against the cross members. The separation of the detent notches 232a and 232b of leading and trailing detent structures 231a and 231b, is equal to the distance between the cross members 231 and 233. The lateral movement of sliding control member 226 through the opposing slots 237 and 238, between its retracted position shown in Fig. 6, and its advanced discharge position shown in Fig. 7 is 15 limited by a shoulder 241 at the leading end of the control member, and by the control tab 242 at the other end whereby the shoulder and control tab limit the degree of slidable movement of the sliding control member in either direction. Thus in its retracted state, the shoulder 241 of the sliding control member 226 abuts the outer edge of cross member 231, and when sliding control member 226 20 is fully advanced, the leading edge 244 of control tab 242 is in contact with the outer portion of support post 236. In this latter, advanced discharge state of sliding control member 226, the notches 232a and 232b engage with the outer and inner edges respectively of cross members 231 and 233 respectively. A discharge orifice 240 is formed through sliding control member 226 is located 25 midway between notches 232a and 232b. The position of the orifice is such that with the lateral movement of sliding control member 226 through the opposing slots 237 and 238 from the retracted position shown at Figure 6 to the advanced discharge position of Figure 7 the orifice is in alignment with the -13 discharge nozzle when the sliding control member is in its advanced discharge position as shown in Figure 7. The intermediate member 225 has the form of a short cylinder open at its lower end with a bore adapted to fit over the end of discharge nozzle 218, and 5 provided at its closed upper end with a central orifice 242 to allow passage of gas discharging from nozzle 218. To provide for varying rates of flow under different operating conditions, mechanisms may be fitted with any of a range of intermediate members, which have various sizes of orifice 242. Gas may be discharged from canister 214 by urging sliding control member 226 10 from its retracted position shown in Fig. 7 to its advanced position shown in Fig. 6. This movement of the sliding control member 226 forces the flat underside 227 of the control member 226 downwardly as the wedge formations 231a and 231 b are driven against the undersides of cross members 231 and 233. The underside 227 of control member 226 thus presses against intermediate 15 member 225 and consequently against the discharge nozzle 218, depressing it to release gas from the canister 214. The present invention is not to be limited in scope by the specific embodiment described herein. The embodiments is intended for the purpose of exemplification only. Functionally equivalent products, formulations and 20 methods are clearly within the scope of the invention as described herein.

Claims (20)

1. An aerosol canister control mechanism for inflation of a borehole plug; said aerosol canister having one end upon which the control mechanism is to be 5 mounted in use, the one end having a discharge nozzle mounted to the upper end, the discharge nozzle associated with a valve which is biased to a closed position, the discharge nozzle having an outlet, whereby displacement of the discharge nozzle in a direction towards the one end to a discharging state will open the valve to permit the contents of the canister to 10 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 control member mounted to the body for slidable movement wherein in use the control member is positioned to be transverse to the canister and the slidable movement of the control member is transverse to 15 the canister, the control member being slidable between a retracted position at which it is not engaged with the discharge nozzle to cause the valve to open and a discharging position at which it is in engagement with the discharge nozzle to displace said discharge nozzle and cause the discharge nozzle to adopt the discharging state, the control member being retained in 20 the body by a retaining means which is able to retain the control member in the retracted position and retain the control member in the discharging position.

2. An aerosol canister control mechanism as claimed at anyone of the - 15 preceding claims wherein said control member is provided with a wedge formation having an inclined leading face rising from a first lower level to raised level; and an intermediate face which an extension of the leading edge but is generally parallel to the to the direction of slidable movement, the intermediate 5 face having at least one first engagement element along its length, the body having at least one second engagement element, said first and second engagement elements being inter-engagable to resist relative movement between the control member and the body.

3. An aerosol canister control mechanism as claimed at claim 2 wherein the inter 10 engagement between the first and second engagement elements permit said slidable movement in a direction away from the retracted position only.

4. An aerosol canister control mechanism as claimed at claim 2 or 3 wherein the control member is provided with a bearing surface which is adapted to slidably engage with the outer end of the discharge nozzle, the bearing surface having 15 at least one portion positioned to be engaged with the discharge nozzle when the control member is at its discharging position to open the valve.

5. An aerosol canister control mechanism as claimed at 4 wherein the intermediate face is provided with a single first engagement element.

6- An aerosol canister control mechanism as claimed at claim 4 wherein the 20 intermediate face is provided with a plurality of first engagement elements and each first engagement element is associated with one of said portions, the degree of discharge from the nozzle of the valve effected by each portion being different.

7. An aerosol canister control mechanism as claimed at claim 4 or 6 wherein the 25 engagement of the intermediate face with the body causes relative movement of the bearing surface towards the one end of the canister to cause movement of the discharge nozzle to open the valve,

8. An aerosol canister control mechanism as claimed at claim 7 wherein the - 16 control member is resiliently urged into contact with the second engagement element.

9. An aerosol canister control mechanism as claimed at claim 8 wherein the biasing is effected at least partially by a spring. 5

10. An aerosol canister control mechanism as claimed at claim 8 wherein the biasing is effected at least partially by the biasing applied to the valve.

11. An aerosol canister control mechanism as claimed at claim 4 or 5 wherein the discharge nozzle has its outlet at its outer end and the outer end is slidably engaged by the bearing surface and said bearing surface closing 10 the outer end when the control member is in the retracted position, the bearing surface having a single portion having an aperture positioned to cooperate with the discharge nozzle when the portion is located proximate the discharge nozzle to provide a flow path for the fluid flowing from the discharge nozzle. 15

12. An aerosol canister control mechanism as claimed at anyone of claims 4, and 6 to 11 wherein the discharge nozzle has its outlet at its outer end and the outer end is slidably engaged by the bearing surface and wherein said bearing surface closes the outer end when the control member is in the retracted position, each portion having an aperture positioned to cooperate 20 with the discharge nozzle when each portion is located proximate the discharge nozzle to provide a flow path for the fluid flowing from the discharge nozzle, each aperture being dimensioned according to desired flow rate required for the respective discharge state.

13. An aerosol canister control mechanism as claimed at anyone of claims 4 25 and 6 to 12 wherein the bearing surface is defined within an elongate slot shaped recess formed in the control member wherein the longitudinal axis of the slot is parallel to the axis of the control member.

14. An aerosol canister control mechanism as claimed at claim 13 wherein the apertures are located at spaced intervals along the recess. - 17

15. An aerosol canister control mechanism as claimed at anyone of claims 4 and 6 to 14 wherein said control member is provided with at least two wedge formations, and the body is provided with two sets of second engagement elements wherein the bearing surface is located between the wedge 5 formations.

16. An aerosol canister control mechanism as claimed at anyone of claims 2 to 15 wherein the wedge formation is provided with an end face which is at the end of the intermediate face remote form the leading face, the end face configured to prevent slidable movement of the control member when 10 engaged thereby.

17. An aerosol canister control mechanism as claimed at anyone of claims 2 to 5 wherein a single first engagement element is provided on each wedge formation to cooperate with one second engagement element.

18. An aerosol canister control mechanism as claimed at anyone of claims 2 to 15 4 and 6 to 16 wherein a plurality of first engagement elements are provided on each wedge formation to cooperate with one second engagement element.

19. An aerosol canister control mechanism substantially as herein described with reference to the accompanying drawings.

20 20. An aerosol canister for inflation of a borehole plug having a control mechanism of the form as defined in anyone of claims 1 to 18 applied thereto and positioned to cooperate with the discharge nozzle.