EP0515389B2 - Stackable drum - Google Patents

Abstract

The invention concerns a large-capacity stackable drum with a substantially cylindrical side wall (3) and top and bottom ends (32, 34). To improve the stackability in particular the long-term stackability an internal hydrostatic pressure which supports the side wall is initially produced, when stacking several drums one on top of the other, in the gas space above the content and in the contents, of the drums stacked underneath, by virtue of the elastic flexibility of the top (32) and/or the bottom (34) of the drum, until a reduced stacking load acting through the top rim or grip ring (38) of the drum into the drumwall (30) is produced or support provided through the bottom rim or grip ring (40).

Description

The invention relates to a stackable barrel, preferably a large volume barrel made of thermoplastic Plastic, e.g. PE (polyethylene), or steel, with im essential cylindrical barrel wall and top and underside barrel bottom, in the near range at least the upper barrel bottom on the outer barrel wall a circumferential gripping ring (handling ring) is provided and at least one of the two disc-shaped ones flat barrel bottoms over a cross-sectional view almost conical or curved in the axial direction to the outside over the barrel gripping ring protruding ring piece with the Barrel wall is connected.

Plastic sheet drums are generally known, the Flat and barrel bottoms on the top and bottom on an incline conical or rounded ring part with the cylindrical barrel walls are connected, e.g. from the German utility model DE-U-87 05 916. Since at such barrels mostly the surrounding hand rims also take over the function of roller tires they are essentially in the radial direction from the outer barrel wall from; continues to exist comparatively large axial projection of the barrel bottoms in Axial direction outwards or a considerable one Spacing the barrel bottoms over the obliquely conical Ring part of these outwardly projecting hand rims. An axial load on these handrims is - if at all - only possible to a very limited extent, as this will cause the radially from the barrel wall to bend protruding L-shaped rings and dents in the Barrel walls would lead. On the stackability Such barrels have no influence on the hand rims. Another such plastic barrel with top and lower grip ring and protruding conically connecting to the top and bottom of the barrel Ring parts are known from FR-A-2 585 330. When stacking such barrels, the Stack load absorption only after deformation of the conical or arched ring pieces of the flat Drum bottoms via a hydrostatic internal pressure build-up; the The barrel casing is not directly or only loaded after deformation of the handling ring (see Figures 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 is normally no uniform support force on the top floor of the stacked barrel when stacked.
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.

In addition, other large-volume sheet drums are generally known, where the gripping rings by an axial extension of the barrel wall or by retracted, recessed barrel bottoms are trained. With such barrels, e.g. even with one usual steel drum, the stack load is carried out exclusively through the rigid stiff barrel jacket. These barrels therefore have - if they are made of plastic - a relatively thick Barrel jacket with little or no elastic axial deformation allows; a hydrostatic internal pressure is such Barrel not usually built up. Provided nevertheless forms an internal pressure, so the flat barrel bottoms bulge outward unhindered without the function of a partial To be able to take over stack load support. It is here in the Principle regardless of whether the barrel is empty or filled, and the The bung is tightly closed or open. Another disadvantage Such a barrel is therefore a correspondingly high one Empty or operating weight.

It is therefore an object of the present invention to improve the stackability of large-volume drums and, in particular, the long-term stacking behavior while at the same time enabling a drum material saving and a drum empty weight reduction.

This object is achieved according to the invention by the features of patent claims 1.
This configuration ensures that when stacking barrels on top of each other in the stacked barrel, which is filled with a filler (e.g. liquid) and is sealed gas-tight, in the upper residual gas space under the top shelf and in the filler initially by elastic compliance of the conical or arched protruding to the outside Ring part of the top plate and / or bottom plate an internal hydrostatic pressure between 0.1 and 0.3 bar, preferably about 0.16 bar, is built up in a defined, reproducible manner if there is a reduced introduction of stacking loads into the outer barrel edge via the handling ring.

Due to the inventive design of the barrel nearby the barrel end surface from the barrel jacket integrally molded upper Barrel ring and / or lower barrel ring, which is essentially a represent 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 in the axial direction protrude outward, being conical ring-shaped Outside areas are connected to the barrel jacket is very advantageous a stack load in the substantially axially Barrel wall trained vertical barrel gripping rings with radial flange edge protruding outwards only after a pronounced defined internal pressure build-up within the barrel. Doing so So first a defined hydrostatic internal pressure is built up and only after a radial preload is the axial Load introduction into the barrel jacket via the hand rims, whereby due to the axial connection of the hand rims with selective loading the acting stack load on a wider circumferential part the barrel wall is distributed. Due to the prevailing internal pressure the risk of denting the barrel jacket becomes one shifted higher axial load. This means that such Barrels can take a much higher stacking load and at the same time a risk of overturning is significantly reduced. This also makes it possible, e.g. given predeterminable Load for the stacked barrel with about 900 kg with a triple drum stack of e.g. 220 1-barrels that the Wall thickness of the barrel wall and thus the empty barrel weight accordingly can be reduced. In the case of a steel barrel, the Use of a steel sheet from e.g. 0.9 mm compared to one previous steel sheet with a wall thickness of 1.0 mm possible.

The wall thickness of a plastic barrel can be, for example, from 3.8 mm can be reduced to 3.3 mm to 3.2 mm. This results in advantageously reducing the operating weight an empty barrel of e.g. 9.0 kg to approx. 8.5 kg and material savings of the plastic raw material.

The barrels according to the invention additionally show through their exploited stabilizing internal pressure a much cheaper Long-term stacking behavior than other known plastic drums on. Due to the axial pressurization of the barrel bottoms and their The barrel jacket needs support on the respective pallet bases only carry a reduced stacking load.

The invention is described below with reference to the drawings schematically illustrated embodiments and described.

Figur 1

ein bekanntes Kunststoff-Faß mit hoch über den äußeren Greifring hinausstehendem Oberboden,

Figur 2

das in Fig. 1 dargestellte bekannte Kunststoff-Faß im untergestapelten Belastungsfalle,

Figur 3

ein anderes bekanntes Faß mit weit über den Oberboden überstehenden oberem Greifring,

Figur 4

das in Fig. 3 dargestellte bekannte Faß im untergestapelten Belastungsfalle,

Figur 5

ein erfindungsgemäßes Kunststoff-Spundfaß,

Figur 6

das in Fig. 5 dargestellte Kunststoff-Faß im untergestapelten Belastungsfalle,

Figur 7

einen Ausschnitt eines erfindungsgemäßen Fasses im Zustand steigender Belastung,

Figur 8

das in Fig. 7 dargestellte Faß im Endzustand einer untergestapelten Belastung,

Figur 9

ein weiteres erfindungsgemäßes Deckelfaß und

Figur 10

das in Fig. 9 dargestellte Deckelfaß im untergestapelten Belastungsfalle.

Show it:

Figure 1

a well-known plastic drum with an upper floor protruding high above the outer gripping ring,

Figure 2

the known plastic barrel shown in Fig. 1 in the stacked load case,

Figure 3

another well-known barrel with an upper gripping ring protruding far above the top surface,

Figure 4

the known barrel shown in Fig. 3 in the stacked load case,

Figure 5

a plastic bung barrel according to the invention,

Figure 6

the plastic drum shown in Fig. 5 in the stacked load case,

Figure 7

a section of a barrel according to the invention in the state of increasing load,

Figure 8

7 in the final state of a stacked load,

Figure 9

another lid barrel according to the invention and

Figure 10

the lid barrel shown in Fig. 9 in the stacked load case.

In FIG. 1 , the reference number 10 denotes the barrel jacket of a generally known, comparatively thin-walled plastic barrel, in which the top bottom 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 piece 14 into the barrel casing 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, which projects high above the outer gripping ring 16.

In the case of the load shown in FIG. 2 for this known barrel, an internal pressure build-up takes place in the gas space 20 and the filled-in liquid 18 by lowering the top plate 12. An axial load on the gripping ring 16 is normally not provided. However, as soon as there is an axial load on the gripping ring with increasing load or deformation of the top plate - in practice, this does not usually take place evenly, but usually, for example, partially or unilaterally through a narrow pallet underfloor board - 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 thereby to an increased risk of the corresponding barrel stack falling over. 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. If the load is excessive, elastic deformation of the gripping ring 24 and compression of the barrel body can occur due to elastic deformation. As a result, when an internal pressure is built up, the barrel top 26 (and barrel bottom) bulges outwards without external resistance (no stack load being applied). Such drums made of thick-walled plastic are expensive because of the material and have 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 . In the edge region of the flat, flat top floor 32, a molded-in filling / emptying bung 36 is arranged. 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. It is important here that in the drum according to the invention the upper or lower drum base 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 base 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 case of loading of the barrel according to the invention is shown schematically by a pallet 56 placed on it, which exerts a compressive force on the barrel with a stacking load P _s . Due to the protruding barrel bottom design, a defined, reproducible internal pressure P _i 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 32 with the beginning of elastic deformation of the conical lid-ring piece 42, an additional stabilizing compressive force in the radial surface direction - illustrated by arrow 58 - acts on the barrel jacket 30 from the inside in the connection area 60 between the barrel casing 30 or the upper gripping ring 38 and the cover ring piece 42. In the case of a larger load, for example two stacked barrels (FIG. 8), a substantial part of the compression force is exerted in the axial direction on the end edge 48 of the upper gripping ring 38 Barrel wall initiated.
Due to the prevailing internal pressure P _i and the additionally stabilizing pressure force from the cover ring piece 42 - both of which counteract a buckling 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 stacking load, as a result of which material fatigue, aging or decreasing long-term stiffness with loss of strength as with conventional plastic barrels does not occur at all or only very much 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 peripheral region of the barrel cover 62. The drum cover 62 is supported with its lower peripheral flange 64 on a jacket flange 66 projecting from the outer drum wall 30. 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 and tightly closed on the barrel opening or barrel wall in a gas-tight and liquid-tight manner.

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 barrel barrel 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 protrusion, so that the internal pressure P _i has built up in the barrel and axial compressive forces from the upper gripping ring 38 via the cover flange 64 and the jacket flange 66 in the axial direction the barrel jacket 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.

Due to the large contact diameter (same diameter of the Gripping ring 38) there is a better compression force distribution in the Barrel wall, less overall deformation and greater lateral stability.

The barrel gripping rings could, for example, in a modification of the invention also as separate prefabricated ring pieces on the outer Barrel jacket put on, shrunk on, glued on and / or welded on be.

Furthermore, the barrel design according to the invention could also be realized in a bung barrel by prefabricating the entire top floor and / or bottom floor 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 on the outer drum wall in the vicinity of the corresponding drum bottom and at least one drum bottom projecting beyond the drum gripping ring in the axial direction is achieved functionally by stacking one on top of the other of barrels in the lower gas-tight barrels in the remaining residual gas space and in the filler or the liquid, initially by means of elastic compliance of the top and / or bottom, 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 an improved stacking behavior, in particular long-term stacking behavior, can be achieved. If the circumferential gripping ring, which is formed in the axial direction in the extension of the barrel wall, is subjected to punctual loading, the stacking load which occurs is advantageously distributed over a larger peripheral region of the barrel wall.

Claims (7)

1. A large-volume, stackable barrel having a substantially cylindrical barrel wall (30) and upper and lower barrel heads (32,34), wherein in the vicinity of at least the upper barrel head (32) there is an encircling grab ring (38) (handling ring) provided on the outer barrel wall (30) and wherein at least one of the two disc-shaped barrel heads (32,34) is connected to the barrel wall (30) via an annular portion (42,44) which - when viewed in cross-section - projects outwards beyond the upper end-edge of the grab ring (38) in the axial direction in a substantially conical or convex manner, the height of the projection (52, 54) of at least one barrel head (32, 34) beyond the grab ring (38, 40) being one to five times the wall thickness of the barrel head (32, 34), an inner pressure build-up taking place through deformation of the conical or convex annuar portion(s) when the barrel is loaded in the full state by a stack, characterised in that one of the outwards projecting annular portions (42, 44) of the upper head (32) or of the barrel lower head (34) is resiliently deformable to such an extent that a supporting hydrostatic pressure between 0.1 and 0.3 bar, preferably approximately 0.16 bar, can firstly be built up in the barrel interior when the stack load can be transmitted into the outer barrel wall (30) via the outer grab ring (38, 40) which is substantially in the axial extension of the barrel wall (30).
2. A barrel in accordance with Claim 1, characterised in that a resiliently deformable annular portion (42) is solely provided at the upper barrel head (2) and an upper barrel grab ring (38) is provided in the extension of the substantially cylindrical barrel wall (30), and the lower head (34) is constructed flush with the lower barrel grab ring (40) or becomes the barrel wall (30) in a substantially direct manner.
3. A barrel in accordance with Claim 1 or 2, characterised in that the height of the projection (52) of the upper barrel head (32) beyond the upper barrel grab ring (18) is approximately three to four times the wall thickness of the barrel wall (30) or barrel upper head (32).
4. A barrel in accordance with Claim 1, characterised in that the height of the projection (52) of the upper head (32) beyond the upper barrel grab ring (38) is approximately three times the barrel wall thickness (30) and the height of the projection of the lower head (34) beyond the lower barrel grab ring (40) is approximately one to two times the barrel wall thickness (30).
5. A barrel in accordance with Claim 1, 2, 3 or 4, characterised in that the substantially conical annular portion (42, 44) which determines the height of the projection (52, 54) of the barrel head (32, 34) beyond the barrel grab ring (38, 40) is in the form of a resiliently deformable crumple zone, e.g. with encircling annular groove profiles.
6. A barrel in accordance with Claim 1, 2, 3, 4 or 5, characterised in that the grab ring (38) is formed by an annular portion (75) extending substantially in the axial direction in the extension of the barrel wall (30) and having a flange edge (74) directed radially outwards, a free space (46) - wedge-shaped when viewed in cross-section - being formed between the inner surface of the annular portion (75) of the grab ring (38) and the conical annular portion (42, 44) of the barrel head (32, 34).
7. A barrel in accordance with any one of the preceding Claims 1 to 6, characterised in that the upper edge of the plug (36) is level with or flush with the outer surface of the upper barrel head (32) or is sunk in slightly lower.

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