WO2025093508A1 - Closure flange sealing collar for reconditioned drums - Google Patents

Abstract

A sealing collar for a reconditioned container having a closure flange replaces an original sealing gasket which has been lost or destroyed in the reconditioning process. The collar comprises an end wall with (a) a radially inner portion matching a surface profile of a flange curl of the closure flange, and (b) a radially outer portion which diverges from the flange curl surface profile and extends radially outward beyond the outer diameter thereof. An annular outer side wall and the radially outer portion of the end wall together define an enlarged volume occupied by a sealing gasket. When the collar is crimped over the flange curl, the sealing gasket is compressed to seal between a flange pocket neck and the flange curl outside diameter.

Description

CLOSURE FLANGE SEALING COLLAR FOR RECONDITIONED DRUMS

[0001] Steel industrial packaging containers such as drums or pails can be reconditioned for re-use (often multiple times) by burning the container in a specially designed oven to remove residue, decontaminate the container, and provide a suitable substrate for painting or lining. During this reconditioning process the original gaskets that are compressed between the container closure plug-receiving closure flanges and the flange pockets in the container are also burned out and therefore the closure flanges no longer provide a leakproof seal. To re-seal the container closure flanges, the cover or lid containing them is typically cut off or otherwise removed from the container, and replaced with a new cover or lid, fitted with new closure flanges and gaskets.

[0002] During the original fabrication of the container, one or more flange pockets are press-formed to extend outwardly of the container lid or cover (and/or are similarly formed in another portion of the container wall), for reception of the closure flanges. An open-ended circular neck is formed extending further outward at the center of each flange pocket, this neck tapering slightly from its base towards its open end. The closure flange has an internally threaded, generally tubular body for reception of a container closure plug. At a bottom end of this body is a radially outwardly extending base plate, with a non-circular outer edge. For example, the Applicant’s Tri-Sure (RTM) closure flanges have base plates of a characteristic octagonal shape. The flange pocket has a corresponding shape in plan, whereby when the closure flange body is fitted through the flange pocket neck from what will be the inside of the container towards the outside, the base plate is snugly received in the flange pocket and prevents the closure flange from turning as the closure plug is screwed in or unscrewed. A gasket is fitted around the closure flange body to rest against the closure flange’s base plate before the closure flange is assembled with the flange pocket. To retain the closure flange in the flange pocket, a thin-walled outer end portion of the closure flange body is curled over the open end of the flange pocket neck, to form the so-called flange curl. This also draws the base plate into the flange pocket and compresses the gasket into the tapering gap between the inside of the flange pocket neck and the closure flange body, to form a fluid-tight seal. It is this seal that is lost when the gasket is destroyed during the container reconditioning process. [0003] US design patents D704,313 S and D706,909 S disclose closure flange sealing collars designed to be placed externally over the closure flange curl and flange pocket neck of a reconditioned container, to act as a replacement for the burned-out closure flange gasket. There is thus no need to remove the container cover or lid and replace the closure flanges. These closure flange sealing collars comprise a cylindrical side wall housing a flow-in gasket, i.e. a low-profile gasket which is applied in liquid form to the inner circumference of the closure flange sealing collar’s side wall and cured in situ. The side wall has an internal diameter approximately equal to the outside diameter of the flange curl, to provide a close sliding fit thereover. The flow-in gasket extends around the inner circumference of the side wall over a limited portion of the height of the side wall, specifically selected so that the cured gasket lies below the bottom edge of the flange curl when the closure flange sealing collar is seated over the flange curl. Therefore, in this position, the flow-in gasket is intended to lie with precision in a target zone, close to and opposite the junction or gap between the bottom edge of the flange curl and the underlying flange pocket neck. The closure flange sealing collar is formed of a malleable metal so that it can then be crimped in place beneath the flange curl. This presses the flow-in gasket inward, to bridge the junction, or enter the gap, between the flange curl bottom edge and the flange pocket neck. It is thereby possible to restore a fluid-tight seal between the closure flange and the flange pocket.

[0004] These closure flange sealing collars however suffer from several problems. The final position of the bottom edge of the flange curl can be quite variable, as can the size of the gap (if any) left between the bottom edge of the flange curl and the flange pocket neck. This is so even for a nominally standard closure flange, with not only variability as between different container manufacturers, but also quite large production tolerances for a given manufacturer. The closure flange sealing collar can sometimes therefore fail to establish an effective seal when crimped. Moreover, the material of the flow-in gasket may suffer from compression set and/or creep relaxation, whereby the seal can fail over time. Still further, the volume of the original gasket may prevent the closure flange from being drawn fully into the flange pocket when the flange curl is formed. This is acceptable when the original gasket is in place because it will hold the closure flange firmly in position. However, when the original gasket is burned out during reconditioning, the closure flange can become loose in the flange pocket. The closure flange sealing collar may then fail to establish a seal when crimped, or an initial seal may be broken later, when the closure flange shifts during handling of the container or in a drop test. Finally, the flow-in gasket is available in a limited range of materials and is not chemically compatible with a broad range of container contents.

[0005] Some or all of these problems are addressed by the present invention, which provides a sealing collar for a reconditioned container having a closure flange, the sealing a collar comprising: an end wall with a radially inner portion profiled to substantially match a surface profile of a flange curl of the closure flange; an annular outer side wall depending from the end wall; and a sealing gasket within the annular outer side wall; characterized in that: the end wall comprises a radially outer portion which diverges from the flange curl surface profile and extends radially outward beyond the outer diameter of the flange curl surface profile whereby the end wall radially outer portion and the annular outer side wall together define an enlarged volume occupied by the sealing gasket. Compared to US design patents D704,313 S and D706,909 S, the replacement sealing gasket is therefore less accurately targeted on the junction or gap between the bottom edge of the flange curl and the underlying flange pocket neck when the closure flange sealing collar is seated on the flange curl, which might be expected to result in poorer sealing performance. However, the larger outer diameter allows the gasket to be compressed sufficient to provide a seal between the flange pocket neck and the flange curl outside diameter when the closure flange sealing collar is crimped into place over the flange curl. Accurate targeting is therefore no longer as necessary, and the closure flange sealing collar can achieve effective seals against a wider variety of flange curl and flange pocket neck geometries. Moreover, the increased bulk of the gasket provides a greater margin of elastic residual stress energizing the gasket in the crimped-on closure flange sealing collar, whereby the gasket is less prone to compression set and creep relaxation. Still further, the enlarged volume of the gasket causes it to push down on the flange pocket neck and push up against the flange curl as the closure flange sealing collar is crimped into place. The closure flange’s base plate is thereby pulled fully home into the flange pocket, eliminating any looseness that might otherwise arise from the absence of the original flange gasket, to provide a more reliable seal. Finally, a wider variety of gasket materials may be used, including not only flow-in gaskets, but also, for example, lathe cut gaskets originally of generally rectangular cross- section, in any suitable material chemically compatible with the container contents.

[0006] The annular outer side wall of the closure flange sealing collar may taper in internal diameter, in a direction from a free bottom edge towards where the annular outer side wall joins the end wall. The internal taper may be used to retain the annular, resilient sealing gasket within the sealing collar as a friction fit. The closure flange sealing collar including the sealing gasket may therefore be supplied to the customer as a complete subassembly, ready to be seated over a flange curl and then crimped to form an annular seal between the flange curl and the flange pocket neck. Alternatively, the sealing gasket may readily be removed from the remainder of the closure flange sealing collar (or may be delivered to the customer as a separate component). The sealing gasket may therefore be fitted about the flange curl as a first step, and the remainder of the sealing collar then seated over the sealing gasket and flange curl, ready for crimping. The internal taper of the annular outer side wall may aid placement of the remainder of the sealing collar over the sealing gasket and flange curl.

[0007] The annular outer side wall of the closure flange sealing collar may comprise a reinforcing band at or near to its lower edge. This may serve to increase the hoop strength of the annular outer side wall, and/or to control or eliminate undesirable wrinkling or buckling of the annular outer side wall as it is crimped into its final position in use.

[0008] The reinforcing band may comprise a radially inwardly directed lip. The radially inwardly directed lip may serve to retain the sealing gasket in the closure flange sealing collar, both prior to use and during crimping of the sealing collar onto the flange curl and flange pocket neck. [0009] The reinforcing band may comprise a curled edge. This may be used to conceal any sharp edges of the annular outer side wall, and may also allow the annular outer side wall to remain crimpable as required.

[0010] The end wall radially inner portion may provide a sealing land positioned for co-operation with a closure plug sealing gasket. Thus, the end wall radially inner portion may extend downwardly and radially inwardly over the flange curl in use, to cover the portion of the flange curl that would normally provide the sealing land for the closure plug gasket. The closure flange sealing collar may thus be used to refurbish a closure flange in which this original sealing land has been damaged. [0011] Alternatively, the end wall radially inner portion may terminate radially outward of the closure flange’s plug sealing land. This allows the closure plug and its sealing gasket to co-operate with the closure flange’s original plug sealing land in the ordinary way.

[0012] The end wall radially outer portion may extend radially outward from the flange curl surface profile substantially from a point where the outer edge of the flange curl surface profile becomes vertical. Thus, the end wall can center the closure flange sealing collar over the flange curl and prevent extrusion of the gasket. Yet the gasket can still have sufficient volume to make a reliable seal against the lip of the flange curl and to push down on the closure flange pocket neck and push up against the flange curl as the closure flange sealing collar is crimped into place.

[0013] The present invention also provides a method for refurbishing a container having a closure flange with a flange curl curled over a flange pocket neck, the method comprising: providing a closure flange sealing collar comprising: an end wall with a radially inner portion profiled to substantially match a surface profile of the flange curl; an annular outer side wall depending from the end wall; and a sealing gasket within the annular outer side wall; placing the closure flange sealing collar over the flange curl and flange pocket neck; and crimping at least a portion of the annular outer side wall; characterized in that: the end wall comprises a radially outer portion which diverges from the flange curl surface profile and extends radially outward beyond the outer diameter of the flange curl surface profile whereby the end wall radially outer portion and the annular outer side wall together define an enlarged volume occupied by the sealing gasket and the crimping of the annular outer side wall causes the sealing gasket to form a fluid-tight seal between an outer diameter of the flange curl and the flange pocket neck.

[0014] A lower portion of the annular outer side wall may be crimped, and an upper portion of the annular outer side wall may remain substantially uncrimped. [0015] The invention and some of its optional features and advantages are further described below with reference to illustrative embodiments shown in the drawings, in which:

FIG. 1 on the left-hand side is a schematic radial cross-section through a prior art closure flange sealing collar; and on the right-hand side is a schematic radial cross section showing this closure flange sealing collar placed over the curl of a reconditioned container closure flange, prior to attempted securing and sealing by crimping;

FIG. 2 is a cross-sectional view showing a closure flange sealing collar corresponding to that of FIG. 1, crimped into place;

FIG. 3 is a top perspective view of one example of a closure flange sealing collar and its gasket, embodying the present invention;

FIG. 4 is a bottom perspective view of the closure flange sealing collar and gasket of FIG. 3;

FIG. 5 is a vertical cross-section on a diameter, through the closure flange sealing collar and gasket of FIGs. 3 and 4;

FIG. 6 is a side view showing the closure flange sealing collar and gasket of FIGs. 3-5 crimped onto a closure flange of a container, and a closure plug screwed into the closure flange;

FIG. 7 is a cross-sectional view on a diameter of the closure flange sealing collar and gasket of FIGs. 3-5 crimped onto a closure flange of a container, without a closure plug in place;

FIG. 8 corresponds to FIG. 7, but shows the closure plug screwed into the closure flange; FIG. 9 corresponds to FIG. 5, but shows a second embodiment of the invention; FIG. 10 corresponds to FIG. 5, but shows a third embodiment of the invention; FIG. 11 corresponds to FIG. 5, but shows a fourth embodiment of the invention; FIG. 12 is a cross-sectional view on a diameter, showing the closure flange sealing collar and gasket of FIG. 9 crimped onto a closure flange of a container;

FIG. 13 corresponds to FIG. 12, but shows a closure plug screwed into the closure flange;

FIG. 14 is a side view showing the closure flange sealing collar and gasket of FIG. 10 crimped onto a closure flange of a container, and a closure plug screwed into the closure flange;

FIG. 15 is a cross-sectional view on a diameter, showing the closure flange sealing collar and gasket of FIG. 10 crimped onto a closure flange of a container, and a closure plug screwed into the closure flange; and

FIG. 16 is a cross-sectional view on a diameter, showing the closure flange sealing collar and gasket of FIG. 11 crimped onto a closure flange of a container, and a closure plug screwed into the closure flange.

[0016] Referring to FIG. 1, there is shown a portion of a wall 10 of a steel industrial packaging container, such as the lid or end wall of a pail or drum. A flange pocket 12 is press-formed to extend outwardly of the container wall 10, for reception of a closure flange 14. A tapering, open-ended circular neck 16 is formed extending further outward at the center of the flange pocket 12. The closure flange 14 has an internally threaded generally tubular body 18 for reception of a container closure plug (not shown in FIG. 1). At a bottom end of the body 18 is a radially outwardly extending base plate 20, with a non-circular (e.g. octagonal) outer edge. The flange pocket 12 has a corresponding shape in plan, whereby when the closure flange body 18 is fitted through the flange pocket neck 16 as shown in FIG. 1, the closure flange’s base plate 20 fits into the flange pocket 12 and prevents the closure flange 14 from turning as the closure plug is screwed in or unscrewed. To retain the closure flange 14 in the flange pocket 12, a thin-walled outer end portion of the closure flange body 18 is curled over the open end of the flange pocket neck 16, to form the flange curl 22. The container has been subjected to a reconditioning process. Thus FIG. 1 also shows the tapering gap 24 between the inside of the flange pocket neck 16 and the closure flange body 18, which originally housed a sealing gasket, now destroyed and lost because of the container reconditioning process.

[0017] FIG. 1 also shows a known closure flange sealing collar 30, as disclosed for example in U.S. design patents D704,313 S and D706,909 S, fitted over the flange curl 22 but prior to being crimped into its final, fully installed, shape and position. This sealing collar 30 is punched and press-formed from corrosion-resistant steel sheet and is shaped to have a cylindrical outer side wall 32. An end wall 34 of the sealing collar 30 curves radially inward from an upper end of the side wall 32. The curved profile of the end wall 34 matches the shape of the flange curl 22. A low-profile flow-in gasket 36 extends around the inner circumference of the side wall 32 over a limited portion of the height of the side wall 32, specifically selected so that the cured gasket 36 lies immediately below the bottom edge of the flange curl 22 when the closure flange sealing collar 30 is seated over the flange curl 22. Therefore, in this position, the flow-in gasket 36 is intended to lie with precision in a target zone, close to and opposite the junction or gap 26 between the bottom edge of the flange curl 22 and the underlying flange pocket neck 16. Crimping the closure flange sealing collar 30 onto the flange curl 22 and flange pocket neck 16 may therefore press the flow-in gasket 36 inward, to infiltrate the junction or gap 26, as shown in FIG. 2. It is thereby possible to restore a fluid-tight seal between the closure flange 14 and the flange pocket 12.

[0018] However, the final position of the bottom edge of the flange curl 22 can be quite variable, as can the size of the gap 26 (if any) left between the bottom edge of the flange curl 22 and the flange pocket neck 16. The flange sealing collar 30 can sometimes therefore fail to establish an effective seal when crimped. Moreover, the material of the flow-in gasket 36 may suffer from compression set and/or creep relaxation, whereby an initially leakproof seal can fail over time. Still further, the volume of the now lost original gasket may have prevented the closure flange 14 from being drawn fully into the flange pocket 12 when the flange curl 22 was formed, whereby a gap 28 exists between the closure flange base plate 20 and the adjacent top wall of the flange pocket 12, as indicated in FIG. 1. After reconditioning of the container, the closure flange 14 can therefore become loose in the flange pocket 12. The flange sealing collar 30 may then fail to establish a seal when crimped, or an initial seal may be broken later, when the closure flange 14 shifts during handling of the container or in a drop test. Finally, the flow-in gasket 36 is available in a limited range of materials and is not chemically compatible with a broad range of container contents. [0019] FIGs. 3-8 show a sealing collar 130 which constitutes a first illustrative embodiment of the invention, and its use in sealing a closure flange of a reconditioned container. The closure flange sealing collar 130 comprises an end wall 134 with a radially inner portion 134a having a curved profile which may substantially match a complementary portion of the surface profile of the closure flange curl 22. The end wall radially inner portion 134a extends from a central circular aperture 110, radially outward towards the outer diameter of the flange curl 22. A radially outer portion 134b of the sealing collar end wall 134 diverges from the flange curl surface profile and extends radially outward of the radially inner portion 134a, to beyond the outer diameter of the flange curl 22. An annular outer side wall 132 of the sealing collar 130 depends from the radially outer portion 134b of the end wall, whereby the radially outer portion 134b of the end wall and the annular outer side wall 132 together define an enlarged volume (compare e.g. FIGs. 3-5 and prior art F1G.1) occupied by an annular, resilient sealing gasket 136.

[0020] FIG. 6 shows the sealing collar 130 crimped onto the flange curl (obscured by the sealing collar 130 in this view) and flange pocket neck 16 of a reconditioned container. FIG. 7 is a vertical cross-section on a diameter, through the resulting assembly, without a closure plug in place, and FIG. 8 is a corresponding view with a closure plug 40 in place. As shown in these Figures, a lower portion 132a of the sealing collar’s annular outer side wall 132 has been crimped radially inwardly, whereby a lower portion 136a of the sealing gasket 136 is compressed and deformed radially inward and presses radially inwardly and downwardly against the outer surface of the flange pocket neck 16. A fluid-tight seal is thereby produced between the sealing collar’s annular outer side wall 132 and the flange pocket neck 16. This crimping of the lower portion 132a of the sealing collar’s annular outer side wall 132 also squeezes the sealing gasket 136 upward beneath the rim 22a of the flange curl 22 and substantially hydrostatically compresses an upper portion 136b of the sealing gasket 136, which is trapped between the radially outwardly facing surface of the flange curl 22, the sealing collar end wall radially outer portion 134b, and a relatively non-crimped upper portion 132b of the sealing collar’s annular outer side wall 132. The upper portion 136b of the sealing gasket is thereby energized to form a fluid-tight seal between the sealing collar 130 and the outside diameter of the flange curl 22. [0021] Crimping of the sealing collar’s annular outer side wall lower portion 132a may cause a small portion of the sealing gasket 136 to migrate into any gap 26 between the bottom edge of the flange curl 22 and the underlying flange pocket neck 16. However, such migration is not necessary to form an effective seal, and much of the sealing gasket 136 remains outside this gap. The replacement sealing gasket 136 is therefore less accurately targeted on the junction or gap 26 between the bottom edge 22a of the flange curl and the underlying flange pocket neck 16 when the closure flange sealing collar 130 is seated on the flange curl 22 than the flow-in gasket 36 of the prior art. The closure flange sealing collar 130 can therefore achieve effective seals against a wider variety of flange curl 22 and flange pocket neck 16 geometries.

[0022] Moreover, the increased bulk of the gasket 136 provides a greater margin of elastic residual stress energizing the gasket 136 in the crimped-on closure flange sealing collar 130, whereby the gasket 136 is less prone to compression set and creep relaxation. Still further, in the crimped sealing collar 130, the sealing gasket 136 is pushed down on the flange pocket neck 16 and pushed up against the flange curl 22. The closure flange 14’s base plate 20 is thereby pulled fully home into the flange pocket 12, eliminating any looseness that might otherwise arise from the absence of the original flange sealing gasket, to provide a more reliable seal. Finally, a wider variety of gasket materials may be used, including not only flow-in gaskets, but also, for example, lathe cut gaskets originally of generally rectangular radial cross-section, in any suitable material chemically compatible with the container contents.

[0023] The sealing collar end wall radially outer portion 134b may be dimensioned to extend radially outward from the flange curl 22 substantially from the point where the outer edge of the flange curl 22 becomes vertical, when the not yet crimped sealing collar 130 is placed in position over the flange curl 22. The end wall radially inner portion 134a is thereby effective in centering the closure flange sealing collar 130 over the flange curl 22 and preventing extrusion of the gasket 136 during crimping. Yet the gasket 136 still has sufficient volume to make a reliable seal against the lip of the flange curl 22 and to push down on the closure flange pocket neck 16 and push up against the flange curl 22 as the closure flange sealing collar 130 is crimped into place.

[0024] FIGs. 7 and 8 show that the sealing collar end wall radially inner portion 134a curves inwardly and downwardly to terminate at or near to the upper end of the internal thread of the flange body 18 in use. It thereby covers and replaces the sealing land for the closure plug gasket 112 in the closure flange 14. A damaged plug gasket sealing land can thereby be refurbished using the sealing collar 130. It may in some cases be necessary to use a slightly undersized plug sealing gasket 112 to ensure that the closure plug 40 can be torqued fully home. FIGs. 9, 12, and 13 show an alternative embodiment which is generally like the previously described embodiment, except that the sealing collar 230 has a larger central aperture and the sealing collar end wall radially inner portion 234a therefore does not curve as far radially inwardly and downwardly. It instead terminates at an inner margin which is close to the apex of the flange curl 22 in use. When the sealing collar 230 is fitted to the closure flange 14 and flange pocket neck 16, the original sealing land 38 on the inner surface of the flange curl 22, above the closure flange body 18’s internal thread, remains exposed for sealing co-operation with the closure plug gasket 212. A standard-sized closure plug gasket 212 may therefore be used.

[0025] As shown in FIGs. 3, 4, 5 and 9, and in other embodiments, prior to crimping, the annular outer side wall 132, 232 of the sealing collar 130, 230 may taper inwardly from its free bottom edge toward its top edge where it joins the sealing collar end wall radially outer portion 134b, 234b. For example, the uncrimped sealing collar annular outer side wall 132, 232 may be substantially frustoconical. The sealing collar’s sealing gasket 136, 236 may have a substantially rectangular radial crosssection in relaxed form (being for example a lathe-cut gasket). Its outside diameter may be somewhere (e.g. approximately mid-way) between the minimum and maximum inside diameters of the uncrimped sealing collar annular outer side wall 132, 232. The gasket may therefore be pressed into and frictionally retained in the space defined by the sealing collar annular outer side wall 132, 232 and the end wall radially outer portion 134b, 234b; the upper end of the sealing gasket 136, 236 being slightly compressed in the process. The uncrimped sealing collar 130, 230 may therefore be delivered to the customer as a preassembly complete with the sealing gasket 136, 236 in place ready for use. This preassembly can then be seated over the flange curl 22 and flange pocket neck 16, ready to be crimped to form the final sealed assembly. In other cases, for example where the flange curl 22 is not as tightly curled over the flange pocket neck 16 (and is therefore “oversized”), it may be more effective to first remove the sealing gasket 136, 236 from the remainder of the uncrimped sealing collar 130, 230 (or have it delivered separately). The sealing gasket 136, 236 can then be fitted over the flange curl 22 on its own, and the remainder of the sealing collar 130, 230 seated over the sealing gasket 136, 236 as the next step, ready for final crimping.

[0026] FIGs. 10, 14, and 15 relate to a further embodiment, generally like the embodiment shown and described above with reference to FIGs. 3-8, but in which the annular outer side wall 332 of the sealing collar 330 comprises reinforcing band 316 at or near its lower edge. This enhances the hoop strength of the crimped-on sealing collar 330 and reduces or eliminates undesirable buckling or wrinkling of the annular outer side wall 332 as the sealing collar 330 is crimped into its final secured position. The reinforcing band 316 may for example comprise a radially inwardly directed lip, which can serve to retain the sealing gasket 336 in the remainder of the sealing collar 330 both prior to and during crimping. The reinforcing band 316 may comprise a curled edge. This leaves no exposed sharp edges at the lower end of the sealing collar 330. It also still allows the lower portion 332a of the sealing collar’s annular outer side wall 332 to be crimped about the flange curl 22 and flange pocket neck 16 as required, and may assist in preventing extrusion of the sealing gasket 336 during such crimping.

[0027] The various alternative features and/or equivalent features of the different embodiments described above may be combined in any technically compatible way. For example, FIGs. 11, 14, and 16 show a further embodiment in which the sealing collar 430 employs a larger central aperture and “short” sealing collar end wall radially inner portion 434a similar to 234a of FIGs. 9, 12, and 13, whereby the original sealing land 38 is left exposed for co-operation with a full-sized, standard plug gasket 412 like the gasket 212 of Figure 13. However, the sealing collar 430 also employs an annular outer side wall 432 with a curled lower edge 416 like the annular outer side wall 332 with curled lower edge 316 of FIGs. 10, 14, and 15, rather than having a plain, non-curled lower edge as shown in FIGs. 6, 9, 12, and 13.

[0028] In any of the above-described embodiments, the sealing collar end wall and annular outer side wall may be formed in one piece, e. g. stamped and pressed from a suitable malleable sheet material, such as corrosion-resistant steel or another suitable metal. The sealing collar sealing gasket may be formed of any suitable elastomer, chosen for compatibility with the container contents, e.g. EPDM, nitrile rubber, or PTFE. Besides being pre-formed e.g. by separate molding, or lathe cutting from a tubular preform, the sealing collar sealing gasket may be formed in situ within the sealing collar, e.g. flow-in or insert molded.

Claims

1. A sealing collar for a reconditioned container provided with a closure flange, the sealing collar comprising: an end wall with a radially inner portion profiled to substantially match a surface profile of a flange curl of the closure flange; an annular outer side wall depending from the end wall; and a sealing gasket within the annular outer side wall; characterized in that: the end wall comprises a radially outer portion which diverges from the flange curl surface profile and extends radially outward beyond the outer diameter of the flange curl surface profile whereby the end wall radially outer portion and the annular outer side wall together define an enlarged volume occupied by the sealing gasket.

2. A sealing collar as claimed in claim 1, in which the annular outer side wall tapers in internal diameter, in a direction from a free bottom edge towards where the annular outer side wall joins the end wall.

3. A sealing collar as claimed in claim 2, in which the internal taper retains the sealing gasket within the sealing collar as a friction fit.

4. A sealing collar as claimed in any preceding claim, in which the annular outer side wall comprises a reinforcing band at or near to its lower edge.

5. A sealing collar as claimed in claim 4, in which the reinforcing band comprises a radially inwardly directed lip.

6. A sealing collar as claimed in claim 4, in which the reinforcing band comprises a curled edge.

7. A sealing collar as claimed in any preceding claim, in which the end wall radially inner portion provides a sealing land positioned for co-operation with a closure plug sealing gasket.

8. A sealing collar as claimed in any of claims 1-6, in which the end wall radially inner portion terminates radially outward of a plug sealing land on the closure flange.

9. A sealing collar as claimed in any preceding claim, in which the end wall radially outer portion extends radially outward from the flange curl surface profile substantially from a point where the outer edge of the flange curl surface profile becomes vertical.

10. A method for refurbishing a container having a closure flange with a flange curl curled over a flange pocket neck, the method comprising: providing a closure flange sealing collar comprising: an end wall with a radially inner portion profiled to substantially match a surface profile of the flange curl; an annular outer side wall depending from the end wall; and a sealing gasket within the annular outer side wall; placing the closure flange sealing collar over the flange curl and flange pocket neck; and crimping at least a portion of the annular outer side wall; characterized in that: the end wall comprises a radially outer portion which diverges from the flange curl surface profile and extends radially outward beyond the outer diameter of the flange curl surface profile whereby the end wall radially outer portion and the annular outer side wall together define an enlarged volume occupied by the sealing gasket and the crimping of the annular outer side wall causes the sealing gasket to form a fluid-tight seal between an outer diameter of the flange curl and the flange pocket neck.

11. A method for refurbishing a container as defined in claim 10, in which a lower portion of the annular outer side wall is crimped and an upper portion of the annular outer side wall remains substantially uncrimped.