AU2017232216B2 - Dosing Apparatus - Google Patents

Abstract

Abstract An embodiment of the invention relates to a dosing apparatus 10 that is adapted to permit selective displacement of a spear 22 between an extended condition and a retracted condition. In the extended condition, the dosing apparatus 10 permits delivery of substances into the pipeline; in the retracted condition the spear 22 is located within the dosing apparatus 22 permitting selectively closing or opening of the valve 16 for either removing the dosing apparatus 10 from the valve means 14 or moving the spear 22 into the extended condition for delivery of substances into the pipeline 12. The dosing apparatus comprises means for impeding expulsion of the delivery means from the retention chamber and means to permit adjustment of the distance between the retention chamber and a distal end of the delivery means. Fig 1

Description

DOSING APPARATUS

TECHNICAL FIELD [0001] The present invention relates to delivery systems and methods for delivery of substances either in particulate, fluideous or gaseous state.

[0002] The invention has been devised particularly, although not necessarily solely, in relation to dosing apparatus including dosing spears for delivering substances either in particulate, fluideous or gaseous state into, for example pipelines or tanks.

BACKGROUND ART [0003] The following discussion of the background art is intended to facilitate an understanding of the present invention only. The discussion is not an acknowledgement or admission that any of the material referred to is or was part of the common general knowledge as at the priority date of the application.

[0004] It is common usage to deliver on a periodical basis substances into pipelines or tanks. For example, bodies of water that are stored in tanks or transported through pipelines require addition of particular substances into the water for maintaining the water in good condition. To add these substances to the water inside tanks and pipelines dosing spears have been developed that permit delivery of the substances into the water. In particular, dosing spears have been developed that connect with valve means such as ball valves. These particular type of spears are adapted to be inserted into the valve means in order to access the interior of a tank or a pipeline to permit delivery of the substances.

[0005] Moreover, on occasion samples of, for example, water contained in tanks or pipelines may need to be taken to conduct analysis to confirm the good condition of the waters stored in the tank or that flows through the pipeline. Taken the samples may be done with spears adapted to collect and retrieve samples from the interior of tanks or pipelines [0006] Typically, spears consist of an elongated conduit adapted to be inserted through that valves means that are fluidly connected to tanks or pipelines. The

2017232216 23 Jan 2019 elongated conduit comprises a distal end for insertion into the tank or pipeline to deliver the particular substance into, for example, the water contained in the tank or pipeline. The elongated conduit comprises also a proximal end adapted to be operatively connected to the source of the particular substance to be delivered into the tank of pipeline.

[0007] For delivering the substance into the tank or pipeline, the valve means (such as a ball valve) is opened and the distal end of the spear is inserted into the tank or pipeline for delivery of the substances. After delivery of the substance, the spear is extracted and the valve closed.

[0008] Conventional spears pose a serious safety hazard because while the valve is in the open condition during insertion or retrieval of the spear into or from, for example, a pipeline the spear may be expulsed causing serious injury to the operator. Expulsion of the conduit of the spear may occur due to internal pressure within the tank or pipeline.

[0009] It is against this background that the present invention has been developed.

SUMMARY OF INVENTION [0010] According to a first aspect of the invention there is provided a dosing apparatus for providing and/or collecting one or more substances to and from a cavity comprising a space to which the dosing apparatus is linked, the dosing apparatus comprising delivery means, a retention chamber adapted to receive the delivery means and to permit selective displacement of the delivery means within the retention chamber between an extended condition and a retracted condition, and means for impeding expulsion of the delivery means from the retention chamber.

[0011] Preferably, the cavity comprises a tank or pipeline.

[0012] Preferably, the delivery means comprises a spear having a passage traversing the spear from a distal end of the spear to a proximal end of the spear.

2017232216 23 Jan 2019 [0013] Preferably, the proximal end of the spear is adapted for permitting fluidly connecting the spear to a substance source to permit delivery of the substance into the cavity through the passage of the spear.

[0014] Preferably, the retention chamber comprises a passage traversing the retention chamber from a distal end of the chamber to a proximal end of the retention chamber.

[0015] Preferably, the proximal end of the retention chamber is adapted for permitting fluidly connecting the retention chamber to the cavity to permit delivery of the substance into the space through the passage of the spear.

[0016] Preferably, the means for impeding expulsion of the spear from the retention chamber comprises a first section of the spear and a second section of the retention chamber; wherein the first and second sections are adapted to engage each other to impede movement of the spear with respect to the retention chamber.

[0017] Preferably, the first section of the delivery means comprises a first stepped section surrounding the spear.

[0018] Preferably, the first stepped section is defined by an increased diameter of the distal end of the spear when compared to the diameter of the section of the spear that extends beyond the distal end and comprises the proximal end of the spear.

[0019] Preferably, the second section of the retention chamber comprises a second stepped section surrounding the inner periphery of the passage of the retention chamber.

[0020] Preferably, the passage of the retention chamber comprises a proximal section and a distal section extending from the proximal section; the proximal section being of reduced diameter when compared to the diameter of the distal section defining the inner stepped section.

[0021] Preferably, the retention chamber comprises a seal assembly to impede fluid exiting the proximal section of the retention chamber.

2017232216 23 Jan 2019 [0022] Preferably, the proximal section of the retention chamber comprises a pair of grooves arranged in a spaced apart relationship with respect to each other and each groove surrounds the inner periphery of the passage of the retention chamber, each groove being adapted to receive an O-ring to define the seal assembly.

[0023] Preferably, the dosing apparatus is adapted to be fluidly connected to the cavity via the valve means.

[0024] Preferably, the distal section of the retention chamber comprises a stepped section having a threaded end for releasably attaching the dosing apparatus to the valve means.

[0025] Preferably, the dosing apparatus is adapted to permit adjustment of the distance between the retention chamber and the distal end of the spear.

[0026] Preferably, the proximal section of the retention chamber comprises an end portion being adapted to receive retention means for sealing off the retention chamber at its proximal section.

[0027] Preferably, the retention means are adapted to maintain the spear at a particular location along the retention chamber for setting the depth that the distal end of the spear is inserted in the pipeline.

[0028] Preferably, the retention means further comprises a stopping nut adapted to be secured at particular locations along the spear to secure the spear at the particular locations within the space, and a retention nut adapted to be secured to a proximal end of the retention chamber.

[0029] Preferably, the stopping nut comprises a shaft collar clamp adapted to releasably secure the stopping nut to the spear.

[0030] According to a second aspect of the invention there is provided a dosing apparatus for providing and/or collecting one or more substances to and from a cavity comprising a space to which the dosing apparatus is linked, comprising delivery means, a retention chamber adapted to receive the delivery means and to permit selective displacement of the delivery means within the retention chamber between an extended

2017232216 23 Jan 2019 condition and a retracted condition, and means to permit adjustment of the distance between the retention chamber and a distal end of the delivery means.

[0031] Preferably, the cavity comprises a tank or pipeline.

[0032] Preferably, the delivery means comprises a spear having a passage traversing the spear from a distal end of the spear to a proximal end of the spear.

[0033] Preferably, a proximal section of the retention chamber comprises an end portion being adapted to receive retention means for sealing off the retention chamber at its proximal section.

[0034] Preferably, the retention means are adapted to maintain the spear at a particular location along the retention chamber for setting the depth that the distal end of the spear is inserted in the cavity.

[0035] Preferably, the retention means further comprises a stopping nut adapted to be secured at particular locations along the spear to secure the spear at the particular locations within the cavity, and a retention nut adapted to be secured to a proximal end of the retention chamber.

[0036] Preferably, the stopping nut comprises a shaft collar clamp adapted to releasably secure the stopping nut to the spear.

[0037] Preferably, the dosing apparatus further comprises means for impeding expulsion of the delivery means from the retention chamber.

[0038] According to a third aspect of the invention there is provided a dosing apparatus for providing and/or collecting one or more substances to and from a cavity comprising a space to which the dosing apparatus is linked, the dosing apparatus comprising delivery means having a distal end to be received in the cavity and a proximal end adapted to be fluidly connected to a fluid source and/or a sample collector, a retention chamber having a distal end adapted to be fluidly connected to the cavity and a proximal end adapted to receive the delivery means and the retention chamber being adapted to permit selective displacement of the delivery means within the retention chamber between an extended condition and a retracted condition, and means

2017232216 23 Jan 2019 to permit adjustment of the distance between the retention chamber and the distal end of the delivery means to releasably secure the distal end at particular locations with respect to the retention chamber for setting the depth at which the distal end of the delivery means is inserted in the cavity, wherein the proximal end of the retention chamber comprises the retention means to permit adjustment of the distance between the retention chamber and a distal end of the delivery means.

BRIEF DESCRIPTION OF THE DRAWINGS [0039] Further features of the present invention are more fully described in the following description of several non-limiting embodiments thereof. This description is included solely for the purposes of exemplifying the present invention. It should not be understood as a restriction on the broad summary, disclosure or description of the invention as set out above. The description will be made with reference to the accompanying drawings in which:

Figure 1 is a cross-sectional view of a particular arrangement of a dosing apparatus in accordance with an embodiment of the invention in opened condition connected to a pipeline via valve means.

Figure 2 is a cross-sectional view of the dosing apparatus shown in figure 1 in closed condition.

Figure 3 is a perspective view of the dosing apparatus shown in figure 3 removed from the valve means;

Figure 4 is a cross-sectional view of the retention chamber of the dosing apparatus shown in figure 3;

Figure 5 is a perspective view of the dosing apparatus in accordance to an embodiment of the invention operatively connected to valve means;

Figure 6 is a perspective view of a retention nut of the dosing apparatus shown in figure 5;

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Figure 7 is a perspective view of a detail of the distal end of the dosing apparatus shown in figure 3 operatively engaged to the valve means shown in figure 5;

Figure 8 is a cross-sectional view of the of the dosing apparatus in opened condition shown in figure 1 along the line 8-8’; and

Figure 9 is a cross-sectional view of the dosing apparatus in closed condition shown in figure 2 along the line 8-8’.

DESCRIPTION OF EMBODIMENT(S) [0040] Figures 1 and 2 shows a particular arrangement of a dosing apparatus 10 in operation. The dosing apparatus 10 is linked to the pipeline 12 (also referred to as cavity); in particular, the dosing apparatus 10 is connected to a pipeline 12 via means for controlling fluid flow such as valve means 14.

[0041] As shown in figures 1 and 2, the valve means 14 comprises a valve 16 such as a ball valve 16. The valve 16 comprises a body 18 having an aperture 20 traversing the body 18 of the valve 16. As will be described with reference to the method of operation of the dosing apparatus 10, in accordance with the present embodiment of the invention, the aperture 20 permits delivery of substances from the exterior into the interior of the pipeline 12 through the valve 16. In alternative arrangements, the aperture 20 permits extraction of samples of substances located in the pipeline 12.

[0042] As will be described with reference to one method of operation of the dosing apparatus 10, the dosing apparatus 10 is adapted to permit selective displacement of the spear 22 between an extended condition and a retracted condition. In the extended condition, the dosing apparatus 10 permits delivery of substances into the pipeline; in the retracted condition the spear 22 is located within the dosing apparatus 22 permitting selectively closing or opening of the valve 16 as will be described below for either removing the dosing apparatus 10 from the valve means 14 or moving the spear 22 into the extended condition for delivery of substances into the pipeline 12.

[0043] In figure 1, the dosing apparatus 10 is fluidly communicated with the interior of the pipeline 12 permitting delivery of substances into the pipeline 12. In this particular condition, the valve 16 is open permitting the distal end 24 of the spear 22 to traverse

2017232216 23 Jan 2019 the body 18 of the valve 16 and to enter the pipeline 12 for delivery of substance into the pipeline 12 through the spear 22. As will be described with reference to the method of operation of the dosing apparatus 10, the dosing apparatus 10 is adapted to secure the spear 22 at particular locations within the pipeline 12; for example, the spear 22 may be moved into the pipeline 12 until the distal end 24 of the spear 22 reaches a particular location above the fluid level within the pipeline 12 as is shown in figure 1; alternatively, the distal end 24 of the spear 22 may be located under the fluid level by moving the spear 22 a longer distance than as in the case shown in figure 1.

[0044] In figure 2 the dosing apparatus 10 is not fluidly communicated with the interior of the pipeline and the valve 16 is closed not permitting fluid communication between the exterior of the pipeline 12 and the interior of the pipeline 12. In this particular condition, the distal end 24 of the spear 22 is located within the dosing apparatus 10 at a particular location that permits closing of the valve 16; in particular, the distal end 24 of the spear 22 is located within a retention chamber 26 of the spear 22.

[0045] Furthermore, as will be described with reference to the method of operation of the dosing apparatus 10, the dosing apparatus 10 is adapted to retain the spear 22 within the dosing apparatus 10 impeding unintentional withdrawal of the spear 22; for example, as described in the earlier section titled Background Art, conventional spears may be expulsed from the valve means 14 during either insertion of the conventional spear into the pipeline 12 or during extraction of the conventional spear from the pipeline 12 and the valve means 14.

[0046] Moreover, as will be described with reference to the method of operation of the dosing apparatus 10, the dosing apparatus 10 is adapted to set the depth that the distal end 24 of the spear 22 in inserted in the pipeline 12. For example, on occasions the distal end 24 of the spear 22 may be located above the water level of the body of water located in the pipeline 12 for delivery of the substances onto the upper surface of the body of water; or, alternatively, the distal end 24 of the spear 22 may be located within the body of water for, for example, obtaining samples of the body of water.

[0047] Referring now to figure 3; figure 3 depicts a particular arrangement of a dosing apparatus 10 in accordance with the present embodiment of the invention.

2017232216 23 Jan 2019 [0048] As shown in figure 3, the dosing apparatus 10 comprises a delivery means such as a spear 22 and a retention chamber 26 adapted to receive the spear 22 to allow sliding movement of the spear 22 within the retention chamber 26.

[0049] The spear 22 comprises a passage 28 extending from the distal end 24 of the spear 22 to the proximal end 30 of the spear 22. The passage 28 permits delivery of the substances into, for example, a tank or pipeline 12 during use of the dosing apparatus 10. For this, the proximal end 30 is adapted to be fluidly connected with a fluid source to permit transfer of the substance between the fluid source and the passage 28 of the spear 22 for delivery of the substance into the pipeline 12 while the spear 22 is in the extended condition so that the distal end 24 reaches into the pipeline as shown in figure 1. In the particular arrangement shown in the figures, the proximal end 30 comprise a threaded section 32 for permitting fluidly connecting the spear 22 to the fluid source.

[0050] Further, as was mentioned before, the dosing apparatus 10 is adapted to hinder expulsion of the spear 22 from the valve means 14. For this the spear 22 comprises means for impeding expulsion of the spear 22 during either insertion or extraction of the spear 22 to or from the pipeline 12.

[0051] In the particular arrangement shown in the figures, these means for impeding expulsion of the spear 22 comprises a stepped section 34 surrounding the spear 22. As shown in figure 3, the stepped section 34 is defined by the increased diameter of the distal end 24 of the spear 22 when comparted to the diameter of the particular section of the spear 22 that extends beyond the distal end 24 and ends in the proximal end 30 of the spear 22. As will be described below with reference to the retention chamber 26 of the dosing apparatus 10, the interior of the retention chamber 26 is adapted to receive the stepped section 34 to impede expulsion of the spear 22 from the retention chamber

26.

[0052] Figure 4 shows a cross-section of the retention chamber 26. As shown in figure 4, the retention chamber 26 comprises a body 36 and a passage 38 traversing the body 36. The passage 38 is adapted to receive the spear 22 and permit sliding movement of the spear 22 between an extended condition (see figures 1 or 8) and a retracted condition (see figures 2 or 9).

2017232216 23 Jan 2019 [0053] As mentioned before, the interior of the retention chamber 26 is adapted to receive the stepped section 34 of the spear 22 to impede expulsion of the spear 22 from the retention chamber 26. For this the passage 38, traversing the retention chamber 26, is configured to define a stepped inner section 40 adapted to receive the stepped section 34 of the spear 22. During movement of the spear 22 from the extended condition (see figure 8) to the retracted condition (see figure 9), the stepped section 34 of the spear 22 approaches the stepped inner section 40; once the spear 22 is in the retracted condition, the stepped section 34 of the spear 22 and the inner stepped section 40 of the retention chamber 26 abuts each other. The fact that both stepped sections 34 and 40 abut each other impedes further reversing movement of the spear 22 and thus, the spear 22 is hindered from being expelled from the retention member 26 during handling of the spear during, for example, the process of delivering substances into the pipeline.

[0054] Further, as can be appreciated at figure 4, the passage 38 of the retention chamber 26 comprises a proximal section 42 and a distal section 44 extending from the proximal section 42. The proximal section 42 is of reduced diameter when compared to the diameter of the distal section 44. The proximal section 42 due to its reduced diameter forms the inner stepped section 40 which as mentioned before in conjunction with the stepped section defined by the distal end 24 of the spear 22 stops the spear 22 from being expulsed out of the retention chamber 26.

[0055] The retention chamber 26 comprises a seal assembly to impede fluid exiting the proximal section 42 of the retention chamber 26. For this, the proximal section 42 comprises a pair of grooves 46 arranged in a spaced apart relationship with respect to each other and each groove 46 surrounds the inner periphery of the passage 38 of the retention chamber 26. Each groove 46 is adapted to receive an O-ring. The pair of Orings defines the seal assembly impeding fluid from exiting the dosing apparatus 10 during operation of the dosing apparatus 10.

[0056] Furthermore, the proximal section 42 of the retention chamber 26 comprises an end portion 48 being adapted to receive retention means such as a retention nut 50 - see figure 6. In the particular arrangement shown in the figures, the end portion 48 comprises a thread for receiving the retention nut 50 for sealing off the proximal end of the retention chamber 26 as can be appreciated in, for example, figure 5.

2017232216 23 Jan 2019 [0057] The dosing apparatus 10 is adapted to be attached to means for controlling fluid flow such as a valve means 14. As can be appreciated in figures 1 and 2, during operation of the dosing apparatus 10, the dosing apparatus 10 is adapted to be fluidly connected to a pipeline 12 via the valve means 14. For this the distal section 44 of the retention chamber 26 comprises a stepped section 45 having a threaded end to permit attachment of the dosing apparatus 10 to the valve means 14.

[0058] Moreover, it was mentioned before that the spear 22 may be located in an extended condition in order to be able to reach into, for example, the interior of the pipeline 12 as shown in figure 1. In a particular arrangement of the present embodiment of the invention, the dosing apparatus 10 is adapted to permit adjustment of the distance between the retention chamber 26 and the distal end 24 of the spear 22.

[0059] Adjustment of this particular distance permits setting the depth that the distal end 24 of the spear 22 is inserted in the pipeline 12; this is particularly advantageous because the distal end 24 of the spear 22 may, for example; be located at a desired location within the pipeline 12 depending on the particular type of use that will be given to the spear 22. For example, on occasions the distal end 24 of the spear 22 may be located above the water level of the body of water located in the pipeline 12 for delivery of the substances onto the upper surface of the body of water; or, alternatively, the distal end 24 of the spear 22 may be located within the body of water for, for example, obtaining samples of the body of water.

[0060] Adjustment of the distance between the distal end 24 of the spear 22 and the retention chamber 26 is accomplished via a stopping nut 52 shown in figures 3, 8 and 9. By securing the stopping nut 52 at a particular location along the proximal end 30 of the spear 22, the distal end 24 of the spear 22 may be located at a desired distance from the retention chamber 26 while the spear 22 is in the extended condition for insertion into the pipeline 12. In this manner, the distal end 24 may be located at particular locations within the pipeline 12, for example above or within the body of water contained in the pipeline 12.

[0061] In one particular arrangement, the stopping nut 52 may be a shaft collar clamp comprising a screw system for varying the internal diameter of the shaft collar clamp. By varying the diameter of the collar clamp, the stopping nut 52 may be selectively secured to the spear 22 and released from the spear 22.

2017232216 23 Jan 2019 [0062] In operation, the stopping nut 52 may be slid over the spear 22 and located at a particular location - the particular location is such that the distal end 24 of the spear 22 may be located at a particular depth within, for example, the pipeline 12. To secure the stopping nut 52 to the spear 22, the screw system of the collar clamp is tightened. To release the stopping nut 52 from the spear 22, the screw system of the collar clamp is loosened. In the particular arrangement shown in the figures, the retention nut 50 needs to be removed to gain access to the screw system of the shaft collar clamp.

[0063] During operation of the dosing apparatus 10, the depth at which the distal end 24 of the spear 22 is located inside the pipeline 12 may be adjusted via the screw system of the collar clamp. In particular, the retention nut 50 is removed from the retention chamber 26 to provide access to the collar shaft clamp for selectively tightening and loosening the screw system of the shaft collar clamp. This permits selectively securing and releasing the stopping nut 52 from and to the spear 22 to permit movement of the spear 22 with respect to the retention chamber 26 and subsequent fastening of the stopping nut 52 to the spear 22. In this manner, the depth at which the distal end 24 ofthe spear 22 may be located within the pipeline 12 may be adjusted.

[0064] The fact that the dosing apparatus 10 further comprises means for impeding expulsion ofthe delivery means (such as the spear 22) from the retention chamber 26 is particular advantageous because it permits removal of the retention nut 50 from the retention chamber 26 and loosening of the stopping nut 52 without the spear 22 becoming ejected from the retention chamber 26 due to for example internal pressure inside the pipeline 12.

[0065] In operation, the user presents the dosing apparatus 10 to the valve 16 to allow attachment of the dosing apparatus 10 to the pipeline 12. The dosing apparatus 10 is attached to the valve 16 having the spear 22 in the retracted condition and the valve 16 in closed condition as is shown in figure 9.

[0066] After attachment of the dosing apparatus 10 to the valve 16, the valve 16 may be opened. As mentioned before, the retention chamber 24 comprises a seal defined by O-rings 46 impeding, for example, fluid from the pipeline 12 exiting the retention chamber 26.

2017232216 23 Jan 2019 [0067] After opening of the valve 16, the spear 22 may be displaced from the retracted condition as shown in figure 2 to the extended condition as shown in figure 1 for delivery of substances into the pipelines 12. The spear 22 may be displaced by loosening the retention nut 50 for releasing the stopping nut 52 by loosening the screw system of the shaft collar clamp of the stopping nut 52. This permits movement of the spear 22 along the retention chamber 26 as was described earlier.

[0068] Once the delivery process of the substance has been completed, the spear 22 may be returned into the retracted condition to allow closing of the valve 16 and subsequent removal of the dosing apparatus 10 without posing a safety hazard to the operator.

[0069] Modifications and variations as would be apparent to a skilled addressee are deemed to be within the scope of the present invention.

[0070] Further, it should be appreciated that the scope of the invention is not limited to the scope of the embodiments disclosed.

[0071] Throughout this specification, unless the context requires otherwise, the word comprise or variations such as comprises or comprising, will 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.

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Claims (17)

1. A dosing apparatus for providing and/or collecting one or more substances to and from a cavity comprising a space to which the dosing apparatus is linked, the dosing apparatus comprising delivery means having a distal end to be received in the cavity and a proximal end adapted to be fluidly connected to a fluid source and/or a sample collector, a retention chamber having a distal end adapted to be fluidly connected to the cavity and a proximal end adapted to receive the delivery means and the retention chamber being adapted to permit selective displacement of the delivery means within the retention chamber between an extended condition and a retracted condition, and means to permit adjustment of the distance between the retention chamber and the distal end of the delivery means to releasably secure the distal end at particular locations with respect to the retention chamber for setting the depth at which the distal end of the delivery means is inserted in the cavity, wherein the proximal end of the retention chamber comprises the retention means to permit adjustment of the distance between the retention chamber and a distal end of the delivery means.

2. A dosing apparatus according to claim 1 wherein the cavity comprises a tank or pipeline.

3. A dosing apparatus according to claims 1 or 2 wherein the delivery means comprises a spear having a passage traversing the spear from a distal end of the spear defining the distal end of the delivery means to a proximal end of the spear defining the distal end of the delivery means.

4. A dosing apparatus according to any one of claims 1 to 3 wherein a proximal section of the retention chamber comprises an end portion being adapted to receive the retention means for sealing off the retention chamber at its proximal section.

5. A dosing apparatus according to claim 4 wherein the retention means further comprises a stopping nut adapted to be secured at particular locations along the spear to secure the distal end of the spear at the particular locations within the cavity, and a retention nut adapted to be secured to the proximal end of the retention chamber.

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6. A dosing apparatus according to claim 5 wherein the stopping nut comprises a shaft collar clamp adapted to releasably secure the stopping nut to the spear.

7. A dosing apparatus according to any one of claims 3 to 6 wherein the proximal end of the spear is adapted for permitting fluidly connecting the spear to a substance source to permit delivery of the substance into the cavity through the passage of the spear.

8. A dosing apparatus according to any one of claims 1 to 7 wherein the dosing apparatus further comprises means for impeding expulsion of the delivery means from the retention chamber.

9. A dosing apparatus according to claims 8 wherein the means for impeding expulsion of the delivery means from the retention chamber comprises a first section of the delivery means and a second section of the retention chamber; wherein the first section of the delivery means and the second section of the retention chamber are adapted to engage each other to impede movement of the delivery means with respect to the retention chamber.

10. A dosing apparatus according to claim 9 wherein the first section of the delivery means comprises a first stepped section surrounding at least partially the spear.

11. A dosing apparatus according to claim 10 wherein the first stepped section of the delivery means is defined by an increased diameter of the distal end of the delivery means when compared to the diameter of the section of the spear that extends from the distal end of the delivery means to the proximal end of the delivery means.

12. A dosing apparatus according to any one of claims 9 to 11 wherein the second section of the retention chamber comprises a second stepped section surrounding the inner periphery of the passage of the retention chamber.

13. A dosing apparatus according to claim 12 wherein the passage of the retention chamber comprises a proximal section and a distal section extending from the proximal section of the retention chamber; the second stepped section of the retention chamber being defined at the proximal section of the passage of the retention chamber.

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14. A dosing apparatus according to claim 13 wherein the retention chamber comprises a seal assembly to impede fluid exiting the proximal section of the passage of the retention chamber.

15. A dosing apparatus according to claim 14 wherein the proximal section of the passage of the retention chamber comprises a pair of grooves arranged in a spaced apart relationship with respect to each other, each groove surrounding the inner periphery of the passage of the retention chamber, each groove being adapted to receive an O-ring to define the seal assembly.

16. A dosing apparatus according to any one of claims 1 to 15 wherein the dosing apparatus is adapted to be fluidly connected to the cavity via valve means adapted to be attached to the cavity.

17. A dosing apparatus according to claim 16 wherein a distal section of the retention chamber comprises a stepped section having a threaded end for releasably attaching the dosing apparatus to the valve means.