CLOSED-HEAD DRUM WITH LINER, AND METHOD FOR PRODUCING THE SAME

Abstract

A closed-head drum and inliner for storing and transporting liquid or free-flowing filling materials is disclosed. In order to improve the use of liners in closed-head drums, and to facilitate the handling for the users such as the filling and emptying operators, so as to allow the closed-head drum with liner to be handled in the same or similar way as a closed-head drum without a liner, the disclosed technology can enable the liner to abut, attach to, adhere to, and/or to adhesively and/or detachably bonded to inner surfaces of the drum by virtue of a vacuum being created in the space between the inner surfaces of the drum and the outer surface of the liner.

Claims

1. A closed-head drum comprising: a drum body; a first bung connector and a second bung connector; a liner comprising a plurality of liner connectors including: a first liner connector configured to attach the liner to the first bung connector, and a second liner connector configured to attach the liner to the second bung connector; a first bung closure configured to releasably seal the first bung connector, the first bung closure including: a first closure configured to interface with the first bung connector, and a first sealing ring configured to interface with a first sealing portion of the first bung connector to thereby form a first seal when the first bung closure is in a first closed configuration; and a second bung closure configured to releasably seal the second bung connector, the second bung closure including: a second closure configured to interface with the second bung connector, a second sealing ring configured to interface with a second sealing portion of the second bung connector to thereby form a second seal when the second bung closure is in a second closed configuration, and a third sealing ring configured to interface with at least a portion of the second bung connector to thereby seal an interior of the drum body.

2. The closed-head drum of claim 1, wherein the first bung connector and the second bung connector are located on an end wall of the drum body.

3. The closed-head drum of claim 1, wherein: the second bung closure further comprises a flange ring; and the flange ring comprises the third sealing ring.

4. The closed-head drum of claim 1, wherein the third sealing ring is configured to seal an intermediate volume between an exterior liner surface of the liner and one or more interior wall surfaces of the drum body.

5. The closed-head drum of claim 1, wherein the second bung closure comprises one or more adapter rings and a ring nut.

6. The closed-head drum of claim 5, wherein the second bung closure further comprises a safety cap at least partially covering a top of the ring nut, the safety cap comprising a cap opening at least partially aligned with openings of the one or more adapter rings and the ring nut, respectively, such that a passage is formed, the passage configured to permit the second bung closure to interface with the second bung connector when the second bung closure is in the second closed configuration.

7. The closed-head drum of claim 6, wherein: the second bung closure is configured to seal the passage extending through the one or more adapter rings of the second bung closure when the second bung closure is in the second closed configuration; and the ring nut is configured to unscrew from the second bung connector to thereby permit the one or more adapter rings, and the second bung closure when the second bung closure is in the second closed configuration, to be liftable outwardly from the interior of the drum body.

8. The closed-head drum of claim 6, wherein the one or more adapter rings is configured to, when lifted outwardly from the interior of the drum body with the second bung closure, define an annular gap between the third sealing ring and the at least a portion of the second bung connector to thereby permit air to be extracted therethrough from an intermediate volume between an exterior liner surface and one or more interior wall surfaces of the drum body.

9. The closed-head drum of claim 8, wherein the one or more adapter rings is further configured to move, with the second bung closure, in an inward direction toward the interior of the drum body to close the annular gap between the third sealing ring and the at least a portion of the second bung connector, thereby preventing air to move between the intermediate volume and an exterior of the drum body.

10. A drum system comprising: the closed-head drum of claim 8; a vacuum pump; a vacuum attachment in fluid communication with the vacuum pump, the vacuum attachment comprising a vacuum sealing ring configured to form a seal with the second bung connector; and a pulling tool configured to lift the one or more adapter rings conjointly with the second bung closure, the pulling tool being at least partially disposed within the vacuum attachment.

11. The closed-head drum of claim 8, wherein when at least a partial vacuum exists in the intermediate volume: at least a portion of the exterior liner surface abuts the one or more interior wall surfaces; the first bung closure is configured to be removeable from the first bung connector without disturbing the at least partial vacuum in the intermediate volume; and the second bung closure is configured to be removeable from the second bung connector without disturbing the at least partial vacuum in the intermediate volume.

12. The closed-head drum of claim 1, wherein at least a portion of the liner is configured to adhesively bond to one or more interior wall surfaces of the drum body upon thermal activation.

13. A liner configured to insert into a closed-head drum, the liner comprising: a liner wall; and a plurality of liner connectors including: a first liner connector configured to attach the liner to a first bung connector of a drum body, and a second liner connector configured to attach the liner to a second bung connector of the drum body.

14. The liner of claim 13, wherein: a first radially inward annular surface of the first liner connector is configured to permanently attach to an interior surface of the liner; a second radially inward annular surface of the second liner connector is configured to permanently attach to the interior surface of the liner; and all edges of the liner are separated from an interior of the liner, thereby preventing a material located within the interior of the liner from contacting the edges.

15. The liner of claim 13, wherein at least a portion of an exterior liner surface of the liner is configured to adhesively bond to one or more interior wall surfaces of the drum body upon thermal activation.

16. A method comprising: providing a drum body comprising a plurality of bung connectors; providing a liner including: a first liner connector portion having a first free end, and a second liner connector portion; rolling the liner to form a roll; inserting the roll through one of the plurality of bung connectors of the drum body; attaching the first free end of the first liner connector portion to a first bung connector of the plurality of bung connectors; introducing, via the first bung connector, a fluid into an interior of the liner until the second liner connector portion at least partially extends outwardly through a second bung connector of the plurality of bung connectors; cutting away at least some of the second liner connector portion extending through the second bung connector to thereby form a second free end; welding the second free end to the second bung connector; fluidly connecting a vacuum attachment to the first bung connector; extracting air from an intermediate volume between an exterior liner surface of the liner and one or more interior wall surfaces of the drum body via an annular gap between the first liner connector portion and the first bung connector; and attaching the first liner connector portion to the first bung connector to seal the intermediate volume between the exterior liner surface of the liner and the one or more interior wall surfaces of the drum body.

17. The method of claim 16, further comprising placing a safety cap on the first bung connector.

18. The method of claim 16, further comprising providing heat to the liner to thereby cause at least some of the exterior liner surface of the liner to adhere to at least some of the one or more interior wall surfaces of the drum body.

19. The method of claim 16, further comprising removing the liner from the drum body by at least: at least partially separating the first liner connector portion from the first bung connector; and introducing a fluid via the annular gap between the first liner connector portion and the first bung connector and into the intermediate volume to separate the liner from the drum body.

20. The method of claim 19, further comprising: cutting the liner proximate the second free end to thereby separate the liner from the second bung connector; and removing the liner from the drum body via one of the plurality of bung connectors.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0041] The invention will be explained and described in more detail hereunder by means of an exemplary embodiment schematically illustrated in the drawings in which:

[0042] FIG. 1 shows a closed-head drum according to the invention having an inserted liner in a perspective view;

[0043] FIG. 2 shows the inserted liner for the closed-head drum according to FIG. 1 in a side view;

[0044] FIG. 3 shows the rolled-up liner prior to being inserted into the closed-head drum in a side view;

[0045] FIG. 4 shows a sectional part-view about the upper region of the plastics-material closed-head drum having a 2 bung connector and a welded liner connector;

[0046] FIG. 5 shows a sectional part-view of a ventilation and gassing bung connector having an unscrewed bung plug; and

[0047] FIG. 6 shows a further sectional part-view about the region of the ventilation and gassing bung plug, having a vacuum bell jar placed thereon.

DETAILED DESCRIPTION

[0048] As a preferred exemplary embodiment a closed-head drum from thermoplastic plastics material, which is equipped with an inserted liner 22 composed of a thin-walled plastics-material film, is identified by the reference sign 10 in FIG. 1. As mentioned, the invention could likewise be applied to other plastics-material containers such as canisters, small drums, lidded drums having bung lids, or pallet containers.

[0049] For the application, or use, respectively, with hazardous filling materials the closed-head drum 10 meets particular testing criteria and is provided with a corresponding official certification. The closed-head drum 10 in a mostly used volumetric size of 220 I is particularly suitable for chemical products as well as for foodstuffs. The main components of said closed-head drum 10 are a cylindrical drum wall 12, a disk-shaped lower base 14, and a disk-shaped upper base 16 in which two identically-sized bung connectors 18, 20 which are closable by means of a bung closure are disposed. Closed-head drums of this type have a height of approx. 935 mm and a diameter of approx. 581 mm, are preferably produced by the blow-molding method, and are typically composed of HDPE plastics material. The drum weight is approx. 8.2 kg. Modern drums are composed of three layers, wherein only a thin external layer (20%) is dyed blue and a thin ultrapure inner layer (20%) is composed of new material, while the central support layer (60%) is composed of recycled granules, that is to say from used regenerated plastics material.

[0050] In the case of the closed-head drum 10 according to the invention, the one bung connector is configured as a filling and retrieval bung connector 18, and the other bung connector is configured as a ventilation and aeration bung connector 20. Both bung connectors are configured as 2 bung connectors having a BCS 706 screw fitting.

[0051] A filling and retrieval connector 24 and a ventilation and aeration connector 26 of the liner 22 are fastened so as to be correspondingly assigned in said drum bung connector.

[0052] The liner 22 is illustrated in a side view in FIG. 2. The shape of said liner 22 is adapted to the internal wall of the drum and is composed of a cylindrical liner wall 30, a disk-shaped liner upper base 32, and a disk-shaped liner lower base 34. The liner connector 24, which in terms of the diameter is configured so as to be somewhat larger and longer, for the liner connector 26 of the closed-head drum is disposed at the corresponding position in the upper base 32 of the liner 22, and the somewhat smaller and shorter liner connector 26 for the ventilation and aeration bung connector 20 of the closed-head drum 10 is disposed opposite thereto. An adapter ring 28 which is inserted into the ventilation and aeration bung connector 20 is welded to the shorter liner connector 26.

[0053] The flexible liner connectors 18, 20 herein are produced from the same film material having the same barrier properties as the film material of the flexible liner 22, so as to preclude any disadvantageous diffusion processes that penetrate the plastics material. In the case of a multi-layered asymmetrical film construction of the liner film it is important that the same film material, or the same external film layer, respectively are welded to one another in the annular welding of the welded flange periphery of the liner connectors to the liner wall.

[0054] The liner 22 for a filling volume of 220 l has a height of approx. 930 mm and a diameter of approx. 580 mm. The diameter for the smaller liner connector 26 is approx. 25 mm, and approx. 58 mm for the liner connector 26 that is configured so as to be larger and longer.

[0055] The liner per se, by virtue of the thin-walled configuration thereof, is not dimensionally stable but very flexible, compliant, and adaptable. The wall thickness of the multi-layered liner composite film is approx. 100 m to 300 m, preferably approx. 150 m. At an area weight of approx. 100 to 150 g/m.sup.2 a material weight of approx. 0.15 to 0.3 kg results for a 220 I liner bag. The wafer-thin composite layers herein can be composed of various materials such as, for example, HDPE/LDPE/EVOH/PET/PA/PP or SiOx, having layers of adhesion promoters disposed therebetween, and/or be provided with a glass-fiber or woven-fabric reinforcement. Depending on the specific application, the composite film is equipped with barrier layers, for example in relation to the diffusion of hydrocarbons, oxygen, aromatic substances, or water vapor, and is optionally provided with an antiseptic antibacterial coating or a silver-containing or aluminum-containing vapor-deposited metallized film.

[0056] In terms of construction, the liner connectors 24, 26, by way of a radially inwardly pointing welded flange periphery are welded from the internal side to the liner wall of the liner upper base 32 and thereafter are rolled from the inside to the outside in such a manner that all existing film cutting edges are covered in relation to filling-material contact and no film cutting edge, neither the film cutting edge on the welded flange periphery of the welded liner connectors 24, 26 nor the film cutting edge on the internal-side delimitation of the passage openings in the liner wall, comes into contact with the filled liquid filling material. On account thereof, the full barrier properties are fully preserved even in the case of long transportation and storage periods of the closed-head drums, and any damage to sensitive filling materials caused by diffusion is avoided.

[0057] In order for the particular liner to be implemented, it is in any case important that the annular welding of the two welded flange peripheries of the liner to the internal wall of the liner upper base in terms of production technology has been performed prior to the complete and final welding of the blanks of the multi-layered liner film for the closed liner body, otherwise welding of the film connectors from the inside to the internal wall of the liner upper base is no longer.

[0058] In order for the liner 22 from a flexible thin-walled multi-layered film to be able to be incorporated in the drum interior, said liner 22 is rolled up so as to form a slim rod-shaped roll 36, as can be seen in FIG. 3. Here, at the upper end the smaller liner connector 26 protrudes with the welded-on adapter ring 28, while the larger liner connector 24 is also rolled up and is not visible here. As an important feature pertaining to the blank of the liner, the liner connector 24 having the larger diameter, prior to insertion into the closed-head drum 10, has a length of at least double the diameter of said liner connector 24, and at the free end thereof is welded shut or is closed in a gas tight manner, respectively.

[0059] The liner roll 36 is guided through the ventilation and aeration bung connector 20 of the closed-head drum 10, and the adapter ring 28 is fastened in the bung connector 20 as will be explained in more detail hereunder. Once the adapter ring 28 has been fastened in the ventilation and gassing bung connector 20, compressed air is slowly blown through the hollow adapter ring 28 in the smaller liner connector 26 into the liner such that the latter unfolds and is completely inflated until the opposite larger liner connector 24, still welded shut, in a self-acting manner pokes from below out of the associated filling and retrieval bung connector 18 of the closed-head drum 10.

[0060] The upper region of the closed-head drum 10 having the filling and retrieval bung connector 18 for a BCS 706 standard closure is illustrated in FIG. 4. The 2 bung connector 18, like the bung connector 20 embodied in the same manner, has an internal thread that is configured as a coarse thread; a sealing bed 38, which tapers in terms of diameter, for the sealing ring sitting on the 2 bung plug 44 is situated directly below the internal thread. The filling and retrieval bung connector 18 below the internal thread has a connector neck 40, reduced in terms of diameter, having an annular internal surface 42 as a weld bed surface for the 2 liner connector to be welded therein. The annular internal surface 42 in the connector neck 40 as a weld bed surface is configured so as to be smoothed. The smoothing performed for calibrating the internal surface 42 is performed, for example, by means of a honing tool, a reamer, or a scraper, expediently in an overhead positioning of the drum, wherein peeled plastic-material particle droppings can be suctioned downward; optionally, compressed air is simultaneously blown into the drum body through the other bung connector 20 such that it is in any case precluded that peeled plastics-material particles can make their way into the drum body.

[0061] When the liner 22 is inserted into the closed-head drum 10 and is inflated in such a manner that the liner connector 24, still welded shut, pokes out of the bung connector 18, the liner connector 24 is pulled so as to be taut, is cut open at the top, and inverted over the bung connector 18. The liner connector 24, by means of an expansion welding method, in the radial direction is then welded tightly to the annular internal surface 42 (weld bed surface) and is cut off for an exact fit such that a commercially available 2 bung plug 44 can be screw-fitted and by means of the sealing ring thereof can seal in relation to the sealing bed 38 disposed at the lower end of the internal thread, or the seal counter bearing directly above the weld bed surface, respectively. Apart from calibrating the weld bed surface, no measures or adaptations whatsoever are performed on the standard closed-head drum 10. The advantageous handling of the user-friendly closed-head drum having a liner according to the present invention is very substantially implemented by the particular constructive design embodiment and functional mode of the insert for the aeration and ventilation bung connector 20.

[0062] As is illustrated in FIG. 5, the closure insert for the 2 aeration and ventilation bung connector 20 is composed of at least three parts. The latter are the internally hollow adapter ring 28 having an external radially projecting flange ring 46 which is disposed so as to be approximately centric, a ring nut 48 which encloses the sleeve-shaped adapter ring 28 above the flange ring 46 and which has an external thread and a central passage opening 50, and a safety cap 52 which externally and from above covers the upper part of the aeration and ventilation bung connector 20 and which has a central passage opening 54.

[0063] The hollow sleeve-shaped adapter ring 28 in the upper region of the passage opening thereof is equipped with an internal thread 56. The internal thread 56, conceived as a coarse thread, at the lower end is provided with a sealing bed 58 that is reduced in terms of the diameter.

[0064] A circumferential sealing ring 60 which is preferably configured as a rectangular flat seal and within the bung connector 20, as is the case in the opposite bung connector 18, seals in relation to the sealing bed at the lower end of the internal thread above the diameter-reduced connector neck, is disposed externally on the lower side of the flange ring 46 of the adapter ring 28. The upper side of the flange ring 46 of the adapter ring 28 is impinged from above by the ring nut 48 that encloses the upper region of the adapter ring 28, whose external thread 62, conceived as a coarse thread, engages in the internal thread of the bung connector 18 and presses the sealing ring 60 of the adapter flange ring 46 against the sealing bed (38) at the lower end of the internal thread of the connector 20. The tubular liner connector 26 below the flange ring 46 is welded radially from the outside to the annular-sleeve-type adapter ring 28.

[0065] A smaller bung plug 64 which by way of the sealing ring 66 thereof seals in relation to the sealing bed 58, reduced in terms of the diameter, of the internal thread 56 is screw-fittable from above into the internal thread 56, conceived as a coarse thread, of the adapter ring 28. When the liner 22 is inserted into the drum body and both liner bungs are fastened in the bung connectors of the drum, the ring nut 48 is firmly tightened so that the scaling ring 60 is pressed in a gas-tight manner against the sealing bed 58 in the bung connector 20, and the intermediate air space between the liner and the drum internal wall is closed in a completely air-tight manner. Thereafter, the safety cap 52 with the central passage opening 54 is placed from above onto the aeration and ventilation bung connector 20, wherein the latter is enclosed on the outside in its upper region. The safety cap 52 is preferably configured as a thin-walled plastics-material cap having a releasable or non-releasable snap-fit/latch-fit closure and serves for protecting the ring nut 48 for fixing the adapter ring 56 from unintentional or inexpert opening and for permitting only one access to the ventilation plug 386 which has to be able to be opened when filling and emptying the closed-head drum.

[0066] In the case of a further embodiment, the safety cap 52 is configured as a thin sheet-metal lid with a central passage opening 54, which is non-releasably clinch-fitted and which is additionally covered by a thin-walled closed plastics-material protective cap or seal cap, respectively, having a releasable snap-fit/latch-fit closure. The additional seal cap herein is provided as protection against dirt and rainwater and for unscrewing the bung plug can be easily removed, while the non-releasably placed sheet-metal lid with the passage opening in any case prevents any inadvertent or unauthorized unscrewing of the ring nut and can only be removed using a corresponding tool in the recycling operations.

[0067] In the case of this embodiment of the aeration and ventilation bung 20, a smaller 386 closure is thus inserted between the adapter internal thread and the bung-plug external thread between the bung-connector internal thread and the ring-nut external thread.

[0068] In order for the functioning mode of the closed-head drum 10 according to the invention to be highlighted, it is illustrated in FIG. 6 how a vacuum bell jar 70 having a scaling ring 72 is placed onto the aeration and ventilation bung 20 in order for the intermediate air space between the liner surface and the drum internal wall to be vacuumed. A rod-shaped pulling tool 74 which can be moved up and down, as is indicated by a double arrow, is disposed centrically in the vacuum bell jar 70. The pulling tool 74 at the bottom latches into the bung plug 64 that is tightly screw-fitted into the adapter ring 28. When the ring nut 48 is released or unscrewed, the bung plug 64 together with the adapter ring 28, is slightly lifted by means of the pulling tool 74, such that the seal 60 on the flange ring 46 of the adapter ring 28 is somewhat lifted from the sealing bed 38 in the bung connector 20 and releases an annular gap 76 through which the interfering intermediate air is fully extracted from the intermediate air space between the liner and the drum internal wall. Upon completion of this procedure, the ring nut 48 is screw-fitted and firmly tightened in order for the vacuum to be permanently preserved. On account thereof, the adapter ring 28 by way of the lower sealing ring 60 is tightly pressed onto the sealing bed 38 in the bung connector 20. Thereafter, a safety cap 52 with a centric passage opening 54, which permits free access to the bung plug 64 for the filling and emptying operators, is also placed onto the 2 bung connector 20. The safety cap 52 is intended to prevent any inadvertent releasing or unscrewing of the ring nut and the associated loss of the vacuum. A usual thin plastics-material snap-fit lid for protection against dirt and rainwater can also be snap-fitted over the safety cap 52, or onto the 2 bung connector 20, respectively.

[0069] In the case of the present invention, the liner 22 bears in a fully planar manner like a second skin on the internal surface closed-head drum 10, so as to be adapted to the shape thereof. A substantial advantage of such a second-skin liner lies in that the film bag does not as has been usual to date require such a high tear resistance in relation to wobbling when filling, or in the back-and-forth sloshing of the liquid filling material in transportation movements, since no movement whatsoever of the liner film material occurs herein, because the latter bears firmly and permanently on the internal side of the closed-head drum 10, or is adhesively bonded thereto so as to be detachable, respectively. As a result, it is also possible to use lower-cost tear-sensitive film materials having high barrier properties than previously.

[0070] The present invention does not represent a complicated new construction of a closed-head drum but, in the case of a standard closed-head drum having a liner, rather in a phenomenal manner enables vacuuming of the harmful intermediate air between the liner and the drum internal wall directly after the insertion of the liner, on the one hand, and ventilating the drum interior when filling or aerating the drum interior through one and the same bung connector when removing the filling material, on the other hand. Since this solution is conceived for a known closed-head drum type having two 2 bungs, as is widely commercially used, not only newly produced closed-head drums but all other used closed-head drums of this type existing in the market can also be provided with a new liner and be rendered useful for re-use. [0071] 10 Plastics-material closed-head drum [0072] 12 Cylindrical drum wall (10) [0073] 14 Disk-shaped lower base [0074] 16 Disk-shaped upper base 68 Passage opening (28) [0075] 18 Filling and retrieval bung connector (10) [0076] 20 Degassing and gassing bung connector (10) [0077] 22 Liner (film bag) [0078] 24 Filling and retrieval liner connector (22) [0079] 26 Degassing and gassing liner connector (22) [0080] 28 Adapter ring (26) [0081] 30 Cylindrical internal wall (22) [0082] 32 Disk-shaped liner upper base (22) [0083] 34 Disk-shaped liner lower base (22) [0084] 36 Liner roll (22) [0085] 38 Sealing bed (18) [0086] 40 Connector neck (18) [0087] 42 Weld bed internal surface (40) [0088] 44 2 bung plug (18) [0089] 46 Flange ring (28) [0090] 48 Ring nut [0091] 50 Passage opening (48) [0092] 52 Safety cap [0093] 54 Passage opening (52) [0094] 56 Internal thread (28) [0095] 58 Sealing bed (56) [0096] 60 Sealing ring (46) [0097] 62 External thread (48) [0098] 64 bung plug [0099] 66 Sealing ring (64) [0100] 70 Vacuum bell jar [0101] 72 Sealing ring (70) [0102] 74 Pulling tool (70) [0103] 76 Annular gap