EP0515389A1 - Stackable drum. - Google Patents

Abstract

A large stackable drum has a substantially cylindrical wall (30) and upper and lower faces (32, 34). In order to facilitate stacking, especially long-term stacking when stacking several barrels, an internal hydrostatic pressure which supports the wall of the barrel first accumulates in the empty upper space and in the middle of the barrel. filling the barrels located at the bottom of the stack, taking into account the elastic flexibility of the upper face (32) and / or the lower face (34) of the barrels. The reduced charge of the stack is then transmitted by the outer edge of the barrel or by the transport ring (38) to the wall (30) of the barrel, or the charge rests on the lower edge of the barrel or on the transport ring (40).

Description

 STACKABLE BARREL

The invention relates to a stackable drum, preferably a large-volume drum made of thermoplastic, e.g. PE (polyethylene), or steel, with a substantially cylindrical barrel wall and top and bottom barrel bottom, in which in the vicinity of at least the top barrel bottom on the outer barrel wall a circumferential gripping ring (handling ring) is provided and in which at least one of the two disc-shaped flat Barrel bottoms are connected to the barrel wall via a conical or arched cross section that is almost conical or curved in the axial direction to the outside via the barrel gripping ring.

Plastic sheet drums are generally known, the top and bottom flat barrel bottoms of which are connected to the cylindrical barrel wall via an obliquely conical or rounded ring part, e.g. from the German utility model G 87 05 916. Since the surrounding gripping rings usually also take over the function of roller tires in such barrels, they extend essentially in the radial direction from the outer barrel wall; there is also a comparatively large axial projection of the barrel bottoms in the axial direction outwards or a considerable spacing of the barrel bottoms over the obliquely conical ring part from the gripping rings projecting outwardly. An axial load on these gripping rings is - if at all - only possible to a very limited extent, since this would lead to the bending of the L-shaped rings protruding radially from the barrel wall and to buckling of the barrel walls. The gripping rings have no influence on the stackability of such drums.

When such drums are stacked, the stack load is taken up exclusively after deformation of the conical or arched ring pieces of the flat drum bottoms via a hydrostatic internal pressure build-up; the barrel jacket is not loaded in the axial direction directly or only after the handle ring has been deformed (cf. FIGS. 1 and 2). Since barrels are generally transported and stacked on pallets and these pallets usually do not have a flat support surface on the underside, but two or three parallel, spaced-apart floor boards, there are normally no uniform support forces on the stacking Upper floor of the stacked barrel.

Such a one-sided or uneven loading can easily lead to one-sided yielding of the lower barrel and thus increases the risk of the stacked barrels falling over to the side.

Furthermore, other large-volume sheet drums are generally known, in which the gripping rings are formed by an axial extension of the barrel wall or by retracted, recessed barrel bottoms. With such barrels, e.g. Even in the case of a conventional steel drum, the stack load is carried out exclusively by the rigid, rigid drum casing. These barrels therefore have a relatively thick barrel jacket, insofar as they are made of plastic, which allow little or no elastic axial deformation; A hydrostatic internal pressure is generally not built up in such a barrel. If an internal pressure nevertheless develops, the flat barrel bottoms bulge outward without being able to take over the function of partial stacking load support. In principle, it does not matter whether the barrel is empty or full, and whether the bung is tightly closed or open. A further disadvantage of such a drum is accordingly a correspondingly high empty or operating weight.

It is therefore an object of the present invention to improve the stackability of large-volume drums, and here in particular the long-term stacking method, while at the same time making it possible to save drum material and reduce drum empty weight.

This object is achieved according to the invention in that the height of the protrusion of at least one barrel bottom outwards via the assigned barrel gripping ring is one to five times the wall thickness of the barrel wall. This configuration ensures that when stacked Stacking barrels in the stacked barrel, which with a

Filler (for example liquid) is filled and tightly sealed gas-tight, in the upper residual gas space under the top panel and in the filler first an internal hydrostatic pressure between 0.1 and 0.3 bar due to the elastic flexibility of the top panel and / or bottom panel projecting outwards, preferably about 0.16 bar, is built up to be reproducible in a defined manner before a reduced stacking load is introduced into the outer barrel edge or handling ring.

Due to the design of the barrel according to the invention with the barrel barrel and / or lower barrel ring formed in one piece from the barrel jacket in the vicinity of the barrel end surface, which essentially represent an axial extension of the barrel jacket, and with a flat top and a flat underbody opposite the axial end faces of the carrying and transport rings protrude outward in the axial direction, where they are connected to the barrel casing by means of conical annular outer regions, stacking load absorption is very advantageously carried out in the vertical barrel gripping rings which are essentially axially formed to the barrel wall and which project radially outward Flange edge only after a defined internal pressure build-up inside the barrel. In this case, a defined hydrostatic internal pressure is initially built up and only after a radial prestressing does the axial load introduction into the barrel jacket take place via the gripping rings, whereby due to the axial connection of the gripping rings with selective loading, the stack load acting on a wider one Circumferential part of the barrel wall is distributed. Due to the prevailing internal pressure, the risk of the barrel casing buckling is also shifted towards a higher axial load. This means that such drums can take up a significantly higher stacking load and at the same time the risk of overturning is considerably reduced. Furthermore, it is possible in this way, for example, given a predicted load for the stacked drum with about 900 kg in a triple drum stack of, for example, 220 1 drums, that the wall thickness of the drum wall and thus the empty drum weight are reduced accordingly can. In the case of a steel barrel, this makes it possible to use a steel sheet of, for example, 0.9 mm compared to a previous steel sheet with a wall thickness of 1.0 mm. For example, the wall thickness of a plastic drum can be reduced from 3.8 mm to 3.3 mm to 3.2 mm. This advantageously results in a reduction in the operating weight of an empty drum from, for example, 9.0 kg to approximately 8.5 kg and a material saving in the plastic raw material.

Due to the additionally stabilizing internal pressure that they use, the barrels according to the invention have a much more favorable long-term stacking behavior than other known plastic barrels. Due to the axial pressurization of the barrel bottoms and their support on the respective pallet bottoms, the barrel jacket only has to bear a reduced stacking load.

The invention is explained and described in more detail below on the basis of exemplary embodiments schematically illustrated in the drawings.

Show it:

FIG. 1 shows a known plastic drum with an upper floor protruding high above the outer gripping ring,

FIG. 2 the known plastic drum shown in FIG. 1 in the stacked load case,

FIG. 3 another known drum with an upper gripping ring protruding far beyond the top surface,

FIG. 4 shows the known barrel shown in FIG. 3 in the case of a load being stacked below,

FIG. 5 shows a plastic bung barrel according to the invention,

FIG. 6 the plastic drum shown in FIG. 5 in the case of a load stacked underneath,

FIG. 7 shows a section of a barrel according to the invention in the state of increasing load,

FIG. 8 the drum shown in FIG. 7 in the final state of a stacked load,

Figure 9 shows another lid barrel according to the invention and

Figure 10 shows the lid barrel shown in Fig. 9 in the stacked load case. In Figure 1, the reference number 10 of the barrel jacket of a generally known, relatively thin-walled plastic barrel is referred to, in which the top 12 of the barrel is connected to the barrel jacket 10 via an obliquely conical ring piece 14. In the transition area from the conical ring bag 14 into the barrel jacket 10, a circumferential L-shaped upper gripping ring 16 is arranged. The barrel is filled with a liquid (filling material) 18 approximately up to the height of the gripping ring 16, a gas space 20 remaining free below the upper floor 12 projecting high above the outer gripping ring 16.

In the case of the load shown in FIG. 2 for this known drum, an internal pressure build-up takes place in the gas space 20 and the filled-in liquid 18 by lowering the top plate 12. Normally, an axial load on the gripping ring 16 is not provided. However, as soon as there is an axial load on the gripping ring with increasing load or deformation of the top surface - this usually does not take place evenly in the practice, but e.g. due to a narrow pallet underbody, mostly partially or one-sided - this cannot absorb axial forces or transmit them into the barrel wall, but bends outwards or downwards and in this area leads to premature bulges 22 of the barrel jacket and thus to an increased risk of overturning corresponding drum stack. After relief, this handling ring is no longer safe and manageable.

Another already known drum made of comparatively thick-walled plastic is shown in FIG. Here, the upper gripping ring 24 extends far in the axial direction in extension of the barrel wall 28 beyond the barrel top 26.

As can be seen from FIG. 4, in this drum an axial stacking load can only be introduced via the upper end face of the gripping ring and can be absorbed by the drum wall 28. In the event of excessive loading, a radial expansion of the gripping ring 24 and compression of the barrel body can occur due to elastic deformation. As a result, when an internal pressure builds up, the barrel top plate 26 (and barrel underbody) bulges outwards without external resistance (no support from a stacking load) . Such barrels made of thick

REPLACEMENT LEAF Wall-mounted plastic is expensive because it requires a lot of material and has a high operating weight.

A bung barrel according to the invention with a comparatively thin-walled, essentially cylindrical plastic barrel wall 30, top floor 32 and bottom floor 34 is shown in FIG. A molded-in filling / emptying bung 36 is arranged in the edge region of the flat, flat top floor 32. An upper gripping ring 38 and a lower gripping ring 40 are provided in the vicinity of the barrel wall 30. Barrel top 32 and barrel bottom 34 are connected to the barrel jacket via a conical ring piece 42, 44. This results in a circumferential free space 46 behind the gripping rings 38, 40 for engaging the claws of a corresponding drum gripper or a crane hook. A characteristic feature of the invention is that in the barrel according to the invention the upper or / and lower barrel bottom 32, 34 protrude beyond the end face 48, 50 of the respective gripping ring 38, 40. 5, the protrusion 52 of the upper drum base 32 over the upper gripping ring 38 and the protrusion 54 of the lower drum bottom 34 over the lower gripping ring 40 is approximately twice as much as the wall thickness of the drum wall 30.

In Figure 6, the load case of the barrel according to the invention is shown schematically by placing a pallet 56, which exerts a Stap ^r ellast Ps a compressive force to the barrel. Due to the barrel base design projecting by a certain amount, a defined, reproducible internal pressure P. of approximately 0.16 bar is built up inside the filled and tightly closed barrel, so that the axial loading of the barrel jacket 30 takes place only after radial prestressing. This advantageously gives a superposition of partially compensating axial and tangential tensile stresses and axial compressive forces.

Another positive effect is illustrated in FIGS. 7 and 8. When the load begins (FIG. 7) - for example due to a stacked barrel - and compression of the top surface 32 with the beginning of elastic deformation of the conical cover ring piece 42, an additional stabilizing compressive force acts in the radial surface direction - illustrated by arrow 58 - von inside on the barrel jacket 30 in the connection area 60 between the barrel jacket

30 or upper gripping ring 38 and the cover ring piece 42. In the case of a larger load, e.g. two stacked barrels (Fig. 8), a substantial part of the compression force is introduced into the barrel wall in the axial direction via the front edge 48 of the upper gripping ring 38.

Due to the prevailing internal pressure P. and the additionally stabilizing pressure force from the cover ring piece 42 - both of which counteract a denting or buckling of the barrel jacket inwards - the stacking property and in particular the long-term stacking behavior of the barrel according to the invention is considerably improved. Due to the internal pressure applied to the barrel bottoms and their support on the pallet bottoms, the barrel jacket only has to bear a significantly reduced stack load, which means that material fatigue, aging or decreasing long-term stiffness with loss of strength as with conventional plastic barrels does not occur at all or only much later.

Another embodiment of a barrel according to the invention is shown in the form of a lid barrel (wide-necked container) in FIG. 9 and FIG. 10. Here the upper gripping ring 38 is arranged in the circumferential area of the barrel cover 62. The drum cover 62. is supported with its lower U flange 64 on a projecting from the outer barrel wall 30 jacket flange 66. The upper edge of the barrel casing 30 engages in a U-shaped recess in the barrel cover 62, in which a sealing ring 68 is arranged. By means of a clamping ring 70 which simultaneously overlaps the cover flange 64 and the casing flange 66, the cover 62 can be prestressed in a gas- and liquid-tight manner on the barrel opening or barrel wall and can be firmly closed.

In the unloaded case (FIG. 9), the surface of the barrel cover 62 has a protrusion 52 of approximately three times the wall thickness of the cover or the barrel casing over the end edge 48 of the upper gripping ring 38. In the event of a load (FIG. 10), the cover 62 is pressed inwards by the height of the overhang, so that the internal pressure P. has built up in the barrel and axial compression forces from the upper gripping ring 38 via the cover flange 64 and the jacket flange 66 in Axial direction in the barrel casing 30 can be initiated. In the area 72 close to the flat lid surface, the conical ring part 42 has a defined crumple zone, for example formed by a circumferential groove profile, which improves the elasticity or resilience of the barrel lid in this area.

Here too, due to the internal overpressure, the barrel casing is stiffened, so that this lid barrel also has better stacking properties and improved long-term stacking behavior due to its special design.

Because of the large contact diameter (equal to the diameter of the gripping ring 38), there is a better distribution of the compressive force in the barrel wall, less overall deformation and greater side stability.

In a modification of the invention, the barrel gripping rings could, for example, also be attached, shrunk, glued or / and welded onto the outer barrel jacket as separate prefabricated ring pieces.

Furthermore, the barrel design according to the invention could also be implemented in a bung barrel by prefabricating the entire upper floor and / or underbody with the respective gripping ring as a separate individual part (for example injection molding) and then welding it to the cylindrical barrel jacket. The increase in the stackability, in particular the long-term stackability, of large-volume drums with at least one circumferential drum gripping ring arranged in the vicinity of the corresponding drum bottom on the outer barrel wall and at least one barrel bottom projecting beyond the barrel gripping ring in the axial direction is achieved functionally that when stacking barrels in the lower gas-tight barrels in the remaining residual gas space and in the filler or the liquid, an internal hydrostatic pressure between 0.1 and 0.3 bar, preferably about 0.16 bar, is built up before vertical stacking load is introduced into the barrel wall via the outer barrel edge or gripping ring and thus improved stacking behavior, in particular long-term stacking behave is achievable. When the circumferential gripping ring, which is formed in the axial direction in the extension of the barrel wall, is subjected to selective loading, the stacking load which occurs is advantageously distributed over a larger peripheral region of the barrel wall.

Reference list

Stack load internal pressure

Claims

_ _PATENT REQUIREMENTS 1.) Large-volume, stackable barrel with an essentially cylindrical barrel wall and top and bottom barrel bottom, in which a peripheral gripping ring (handling ring) is provided in the vicinity of at least the top barrel bottom on the outer barrel wall and at least one of the two disk-shaped ones Barrel bottoms are connected to the barrel wall via an almost conical or curved ring piece projecting outwardly in the axial direction, characterized in that the height of the projection (52, 54) of at least one barrel bottom over the gripping ring (38, 40) is simple up to five times the wall thickness of the barrel wall (30) or the barrel bottom (32, 34), where at least one of the conically outwardly projecting ring pieces (42, 44) of the top tray (32) or / and the Bottom of the barrel (34) is elastically deformable to the extent that a support is initially provided inside the barrel The hydrostatic pressure can be built up before the stacking load can be introduced into the outer barrel wall (30) via the outer gripping ring (38, 40) or barrel rim. (Fig. 5,6) 2.) Barrel according to claim 1, d a d u r c h g e k e n.n z e i c h n e t that only on the upper barrel bottom (2) an elastically deformable ring piece (42) and in extension of the substantially cylindrical. The upper barrel gripping ring (38) is provided in front of the barrel wall (30), and the underbody (34) is flush with the lower barrel gripping ring (40) or essentially merges directly into the barrel wall (30). (Fig.7.8) 3.) Barrel according to claim 1 or 2, characterized in that at the level of the protrusion (52) of the upper barrel bottom (32) on the upper barrel gripping ring (18) about three to four times the wall thickness of the barrel wall (30) or the barrel top (32). 4.) Barrel according to claim 1, characterized in that the protrusion (52) of the upper base (32) over the upper barrel gripping ring (38) about three times and the protrusion of the lower tray (34) over the lower barrel gripping ring (40) is about one to two times the barrel wall thickness (30). 5.) Barrel according to claim 1, 2, 3 or 4, characterized in that the almost conical ring part (42,44), the height of the supernatant (52,54) of the barrel bottom (32,34) over the barrel gripping ring ( 38.40), as an elastically deformable crumple zone, for example is formed with circumferential ring groove profiles. (Fig. 10) 6.) Barrel according to claim 1, 2, 3, 4 or 5, characterized in that the gripping ring (38) by an essentially in the axial direction, in the extension of the barrel wall (30), running ring piece (75) with a radially outward-facing flange edge (74) is formed, with a cross-sectional wedge-shaped free space (46) between the inner surface of the ring piece (75) of the gripping ring (38) and the conical ring piece (42,44) of the barrel bottom (32,34) is trained. (Fig. 5, 6, 7, 8, 9, 10) 7.) Barrel according to one of the preceding claims 1 to 6, d a d u r c h g e k e n n z e i c h n e t that the upper edge of the bung (36) is the same height as or flush with the outer surface of the upper barrel bottom (32) or slightly recessed. (Fig. 5) 8.) Method for increasing the stackability, in particular the long-term stackability, of large-volume drums with at least one circumferential drum gripping ring arranged on the outer drum wall in the vicinity of the corresponding drum bottom and at least one axially over the drum gripping ring. Direction outwardly projecting barrel bottom, characterized in that when stacking barrels - In the lower gas-tight barrels in the remaining residual gas space (76) and in the filler or the liquid (18), first an internal hydrostatic pressure between 0 by elastic compliance of the top plate (32) and / or the bottom plate (34) , 1 and 0.3 bar, preferably about 0.16 bar, is built up before, - A vertical stack load is introduced via the outer barrel edge or gripping ring (38) into the barrel wall (30) and thus an improved stacking behavior, in particular long-term stacking behavior, can be achieved. 9.) Method according to claim 8, characterized in that when the circumferential gripping ring (38, 40) is subjected to selective loading, which is formed in the axial direction in an extension of the barrel wall (30), the stacking load that occurs occurs over a larger circumferential area of the barrel wall ( 10) is distributed.