CA2371202A1

CA2371202A1 - Synthetic-material container

Info

Publication number: CA2371202A1
Application number: CA002371202A
Authority: CA
Inventors: Dietmar Przytulla; Wilhelm Peter Meuleman
Original assignee: Individual
Current assignee: Mauser Werke GmbH; Wiva Verpakkingen BV
Priority date: 1999-04-22
Filing date: 2000-04-20
Publication date: 2000-11-02
Also published as: HUP0105361A3; ATE246124T1; PL350248A1; HUP0105361A2; BR0009880A; AU766998B2; MXPA01010192A; WO2000064756A1; ES2204585T3; US6971540B1; DE10081067D2; EP1171351A1; CZ20013745A3; EP1171351B1; KR20020010133A; IL145626A0; TR200102511T2; AU4554700A; NO20015139L; CZ294748B6

Abstract

The invention relates to a container (10), consisting of a thermoplastic synthetic material which comprises side walls and a flat upper and lower bas e, whereby the upper base has at least one fill and evacuation opening (14). Th e outer periphery of said upper base is equipped with a continuous handling an d transport ring (12). In order to more efficiently utilise hitherto unusable pallet storage areas, lying between the conventional round, plugged barrels in prior art, the container body has an approximately square cross-sectional surface with slightly convex side surfaces and slightly rounded corner areas . To counteract the tendency of the flat container walls to bulge as a result of this construction, the container body is equipped with reinforcing elements (22, 24) which run vertically and/or horizontally.

Description

MAUSER-WERKE GmbH P 01100 PCT
Wl~/A Square Drum (G 1057) Plastic Container Backctround of the Invention This invention relates to a large-volume container made from a thermoplastic material, with lateral walls, flat top and bottom panels of which the top panel is provided with at least one fill/drain hole, and with a continuous circumferential carrying and transport rim.
Large-volume containers of the type discussed are typically in the form of a cylindrical drum having a capacity (volumetric net content) of about 16 to 80 gallons and used for the storage and transportation of liquid bulk material. A commonly employed container design is the bung-type drum with a net capacity of about 58 gallons. When these conventional barrels and drums are stored or shipped in ISO containers, there remains wasted space between the round wall surfaces of neighboring drums.
It is the objective of this invention to introduce a comparable container whose salient feature consists in a modified configuration that permits better pallet-space utilization while its structural design is such as to minimize any inherent tendency to buckle.
Summary of the Invention According to the invention, this is accomplished by means of an approximately square cross-sectional shape of the drum body with slightly convex lateral surfaces and slightly radiused corners. Such a design results in a substantially improved utilization of pallet space. Compared to conventional, round drums, the essentially square drums according to this invention, when stacked side-by-side, leave significantly smaller gaps between them, thus permitting enhanced utilization of previously wasted carrier space (for instance in ISO
containers). In a practical implementation of this invention, the lateral walls of the drum are provided with reinforcing vertical and/or horizontal ribs which will substantially reduce the tendency of the flat lateral wall panels to bulge or buckle. This buckling tendency increases as a function of the internal pressure, building up due to the hydrostatic pressure of the liquid contents, the weight of stacked drums, or the like.
The reinforcing ribs may be in the form of molded-in U- or V-channels facing and protruding inward and/or outward.
In one design version of this invention, a sturdy drum body is obtained by means of continuous circumferential reinforcing elements in the form of enlarged annular wall profiles. These reinforcing annular wall profiles are preferably produced by an upset-stamping process during the blow-molding of the drum body. In order for the upset-stamping-produced reinforcing rings to retain roughly the same outer diameter as the remaining drum wall, they are configured as a continuous, circumferential, fairly flat V-shaped outward-facing indentation.
In another preferred design version, the corners of the drum body are provided with deep angular indentations in such fashion that in the appropriate horizontal plane the drum has a nearly circular cross section. This design as well results in a considerable reduction of the buckling tendency especially in the lower half of the drum, thus permitting high stacking loads.
The plastic container according to this invention further offers the following important features and advantages:
When configured as a bung-type drum, two bungs are provided in suitably recessed bung housings near the perimeter of the top panel of the drum.
In another design version, one central bung or screw cap, possibly protected in a recessed bung well, is positioned in the center of the top panel of the drum.
- The upper perimeter of the drum body is equipped with a continuous L-profile serving as the handling ring for typical barrel handling equipment.
- The reinforcing ribs are in the form of molded-in U- or V-shaped indentations or protrusions facing inward and/or outward.
In one form of implementation, the continuous, circumferential horizontal reinforcing elements are in the form of enlarged annular profiles molded into the drum wall.
The annular profiles are produced by an upset-stamping process during the blow-molding of the drum body.
- The upset-stamping annular profiles may be configured as continuous, relatively flat, outward-facing V-shaped indentations.
Other, preferred reinforcing elements are provided in the corners of the drum body in the form of deep angular indentations, in such fashion that in the horizontal plane concerned the drum body has a nearly circular cross section.
- For enhanced pressure resistance the flat side walls are provided with central, axially molded-in, rib-shaped profiles.
- Where only one continuous reinforcing element is provided, it is positioned in an area of the drum body extending from the mid-point to the lower third of the drum body and preferably at a level about 44% from the bottom panel of the drum. This further increases in advantageous fashion the resistance to a buckling of the flat drum wall sections, resulting in an improved overall stackability of the drums.

Brief Description of the Drawings The following describes and explains this invention in more detail with reference to examples schematically illustrated in the attached drawings in which:
Fig. 1 ~ is a top view of a square drum-type container according to this invention;
Fig. 2 is a side view of a different drum according to this invention, with a partially cross-sectional representation of the upper and lower segments;
Fig. 3 is a cross section through the body of a square drum-type container according to this invention, showing a circular footprint for comparison;
Fig. 4 is a side view of a modified drum according to this invention, with a partially cross-sectional representation of the upper and lower segments;
Fig. 5 is a top view of a preferred embodiment of the invention;
Fig. 6 is a side view of the container of Fig. 5, with a partially cross-sectional representation of the upper and lower segments;
Fig. 7 shows a diagonal cross section of the drum of Fig. 6;
Fig. 8 illustrates the handling of a drum lying sideways;
Fig. 9 illustrates the handling of a tipped drum; and Fig. 10 is a top view of four palletized drums according to this invention.
Detailed Description of the Invention Fig-1 shows a large-volume, blow-molded container 10 in the form of a bung-type thermoplastic drum having a volumetric capacity of about 66 gallons and equipped around its upper drum wall with a continuous L-profile 12 serving as the handling ring. Two bungs 14, protectively mounted in recessed bung wells 16, are located on opposite sides of the top of the drum.
This top view illustrates the inventive design, whereby the drum body has an approximately square cross section, with slightly convex sides and radiused corners.
Fia. 22 illustrates a design version with a central bung 14 set in a bung well 16. In place of an off-center or central bung, one can provide a larger, screw cap-equipped fill/drain opening (with a diameter for instance of 6" or 10"). A screw cap-equipped drum of that type is ideally suited as a reusable container for viscous, pasty or granular bulk material (= Square Drum HOT). In the left half of the illustration, the bottom of the bung-type drum features a continuous, circumferential base ring 18 (= floor-rolling rim), while the right half of the illustration shows a different design without a base ring.
Fi4. 3 shows a cross section through the wall of a square drum according to this invention and, for comparison, a circle of the same circumferential dimension. The circle is indicative of the tendency of a drum to bulge when filled with a liquid. The internal pressure that builds up inside the drum would cause the flat walls to bulge outwards while pulling in the corners, taking on the shape of the least structural stress, that being a circle. To counteract this tendency which would negatively affect the drum according to this invention, the drum is provided with a special, continuous horizontal reinforcement as shown in Fig. 4. In the left half of the illustration, the reinforcing element is a circumferential annular profile 22. In the right half of the illustration the reinforcing element is in the form of inward corner indentations 24. The reinforcing element (annular profile 22 or corner indentation 24) is provided at a level of preferably 44% from the drum bottom, i.e. at the point where the square drum is exposed to maximum buckling pressure. The circumferential annular profile 22 is configured as a shallow V-shaped, continuous indentation 20 in such fashion that the diameter of the annular profile 22 is roughly the same as that of the remaining drum body. Alternatively, the annular profile 22 can stick out slightly so that barrels standing next to one another touch each other by way of the profile.
In the top view of the top of the drum in Fig. 5, the four angular corner indentations 24, outlined by the round dashed lines, are clearly visible. These indentations 24 are thickest in the corner areas, transitioning into the flat surfaces of the side walls in between. In a preferred design version, the drum has a nearly circular cross section in the horizontal plane of maximum continuous indentation. The ratio between the short radius (toward the center of the flat side walls) and the long radius (in the corners) in a square drum is between 1.05 and 1.34 and preferably about 1.22.
Fia. 66 shows the axial indentations 26 (axial ribs) in the middle of the side walls of the square drum, serving to reinforce and stabilize the filled drum against any buckling or bulging when subjected to stacked loads. In this particular design -- in contrast to a conventional square container such as a thin-walled canister -- it is the flat side walls that support the axial stack load while the corner indentations 24 prevent any excessive radial bulging.
Fiq. 7 shows a diagonal cross section. In this case, the container with the angled indentations 24 and smaller corners has the largest overall cross section. It is evident from this illustration how much more volumetric capacity (10%) is obtainable when compared to a cylindrical drum.
Fia. 8 shows a drum according to this invention firmly lying in a sideways position 30. Without an external force, the drum will not roll away in an uncontrolled fashion, yet the rounded corners allow it to be rolled and moved.

Fi4. 99 shows how the drum, when tipped, can be rolled in its slanted position 32. In this slanted position even manual manipulation and rolling of the drum using the base rolling ring is entirely possible without much of an effort.
Fig. 10 shows four square drums set on a standard-34 pallet (45" x 45"), with maximum utilization of the space between the drums. Thus, when drums according to this invention are stacked in an ISO container, for instance when shipped by truck, about 10% more bulk material can be shipped in the same space and at the same cost of transportation.

MAUSER-WERKE GmbH P 01100 PCT
W~~/A Square Drum (G 1057) List of Reference Numbers Square drum container 12 L-ring 14 Bung 16 Bung well 18 Base ring Indentation 22 Annular profile 24 Angular indentation 26 Axial rib 28 Top-panel profile Firm sideways position 32 Slanted position 34 Pallet surface

Claims

1.) Container (10), made of a thermoplastic material, with side walls, flat top and bottom panels of which the top panel includes at least one fill/drain opening (14), and with a continuous circumferential carrying and transport rim (12), characterized in that the drum body has a nearly square cross section with slightly convex lateral surfaces and slightly radiused corners.

2.) Container as in claim 1, characterized in that the container body is provided with vertical and/or horizontal reinforcement elements.

3.) Container as in claim 1 or 2, characterized in that the reinforcing elements are in the form of rib-shaped indentations or protrusions.

4.) Container as in claim 1, 2 or 3, characterized in that the circumferential, horizontal reinforcing elements are enlarged annular profiles (22) formed into the container wall.

5.) Container as in claim 4, characterized in that the annular profiles (22) are produced from the container-wall material in an upset-stamping process during the blow-molding of the container body.

6.) Container as in claim 4 or 5, characterized in that the upset-stamping annular profiles (22) are in the form of a continuous circumferential, relatively shallow, outward facing, integrated V-shaped profile.

7.) Container as in one of the preceding claims 1 to 6, characterized in that only one circumferential reinforcing element is provided and is situated in the area of the lower half of the container body.

8.) Container as in one of the preceding claims 1 to 6, characterized in that the reinforcing element is provided in a certain elevational, horizontal plane in the corners of the container body by means of an approximately V-shaped, angular, inward-facing indentation (24).

9.) Container as claim 8, characterized in that at it deepest point as viewed in the horizontal plane, the indentation is of a crescent or partly circular configuration.

10.) Container as in claim 8 or 9, characterized in that in the area of the angular indentations (24) the container body displays a nearly circular cross section.

11.) Container as in claim 8, 9 or 10, characterized in that, viewed in the axial direction, the container body transitions from the vertical wall to the deepest point of the angular indentation (24) and back to the vertical wall in a conical or convex configuration.

12.) Container as in claim 8, 9, 10 or 11, characterized in that, from its deepest point in the corner area to the lateral center of the flat container wall, the angular indentations (24) extend along a progressively flatter line.

13.) Container as in one of the preceding claims 8 to 12, characterized in that, in the lateral center of the flat container walls, the angular indentations (24) are spaced apart a certain distance without transitioning into one another.

14.) Container as in one of the preceding claims 8 to 13, characterized in that the lateral center of the flat container wall is provided with an axially extending, molded-in reinforcing profile (26).

15.) Container as in one of the preceding claims 1 to 14, characterized in that the circumferential horizontal reinforcing element is situated in an elevational plane of between 30% and 50%, and preferably about 44% of the height of the container body as measured from the bottom panel of the container.

16.) Container as in one of the preceding claims 1 to 15, characterized in that the ratio between the short container radius and the long container radius in the square area of the container is between 1.05 and 1.35 and preferably about 1.22.

17.) Container as in one of the preceding claims 8 to 12, characterized in that the container top panel is provided with at least two molded-in, mutually parallel reinforcing ribs (28).

18.) Container as in one of the preceding claims 1 to 17, characterized in that the top panel is provided in its center with a fill/drain opening which is preferably recessed in a protective bung well and can be closed off by means of a screw-on cap (preferably 6" or 10" in diameter).

19.) Blow mold with two horizontally displaceable mold parts for producing by the blow-molding method a container per one of the preceding claims 1 to 17, characterized in that the blow mold includes a specially configured cavity which, with due allowance for shrinkage, corresponds to the outside dimensions of the square-drum container in accordance with at least one of the above patent claims.