US 3393821 A
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M. A. J. VERLINDEN July 23, 1968 PRESSURE CONTAINER OR BARREL, MORE PARTICULARLY BEER BARREL 2 Sheets-Sheet 1 Filed Oct. 12, 1964 y 23, 1968 M. A. J. VERLINDEN 3,393,821
PRESSURE. CONTAINER 0R BARREL, MORE PARTICULARLY BEER BARREL Filed Oct. 12, 1964 2 Sheets-Sheet 2 FIG. 6
United States Patent 3,393,821 PRESSURE CONTAINER 0R BARREL, MORE PARTICULARLY BEER BARREL Marius Alphonsus Johannes Verlinden, Statenlaan 128, The Hague, Netherlands Filed Oct. 12, 1964, Ser. No. 403,258 Claims priority, application Belgium, Oct. 10, 1963, 638,460 4 Claims. (Cl. 220-5) ABSTRACT OF THE DISCLOSURE A pressure container having a spherical body of plastic material with a substantially uniform wall thickness and two ends parts mounted in direct contact on the spherical body to substantially enclose the same and confer an elongated barrel shape for the container, the end parts being in contact directly with the spherical body at spaced locations and defining a hollow space between the end parts and the spherical body at which there is mounted on the end parts annular rings which provide rolling surfaces for the container.
This invention relates to pressure containers and particularly beer barrels.
Beer barrels must be adapted to withstand an internal pressure of about 3 atmospheres. Such barrels have been made of wood, aluminum alloys or stainless steel.
All pressure barrels, and more particularly the beer barrels mentioned hereinafter, have disadvantages when they are made of the above materials.
A wooden barrel must firstly be very well built because leakages may occur between the staves as a result of tension or shrinkage etc. Also, wood is very sensitive to mildew, because it is an organic product, so that regular treatments are necessary. Also, wooden barrels which contain beer residues and which are not cleaned at the required intervals may result in mildewing on the inside and cleaning then has to be carried out very thoroughly. Finally, wooden barrels are very heavy and difl'icult to handle.
Aluminum barrels are subjected to corrosion both on the inside and the outside by the action of chemical products. The volume of an aluminum or aluminum alloy beer barrel may vary considerably if it is dented or battered. Every aluminum barrel has to be conditioned before filling.
Stainless steel barrels are heavy and very expensive and also undergo changes in volume if they are dented.
Therefore the various barrel making industries have tried to make a beer barrel of plastic material ever since the introduction of such materials.
In practice, four different plastic beer barrels are known and have been subjected to every possible examination in both the laboratory and practice.
The following conclusions have been drawn:
Without exception, all known barrels are made from high-density polyethylene (known as low-pressure polyethylene). Although theoretically various other plastics could be used and it is not impossible that in the future other types of plastics will be produced with the same characteristics as, if not better than, the above-described low-pressure polyethylene, it is doubtful whether it is possible to use in practice any plastics other than those in the polyolefin group, amongst which the present-known types include low-pressure and high-pressure polyethylene, and polypropylene. Because of their nature, the lowdensity polyethylenes can be completely ruled out for the manufacture of beer barrels. Technically it is possible to use low-density polyethylene (high-pressure polyethylene) for the manufacture of a beer barrel but the flexibility of the resultant product and the inadequate surface hardness and certain other features of the resultant product make it inadequate for the production of beer barrels.
Propylene is such a new material that it is still impossible to predict with certainly whether it will be suitable for the production of a plastic beer barrel. However, it cannot be definitely ruled out.
In practice, however, it is preferably the low-pressure homopolymer polyethylene or low-pressure copolymer or low-pressure copolymer polyethylene which has proved to be suitable for the production of a plastic beer barrel and also polyester reinforced by glass-fiber.
Another characteristic of all beer barrels hitherto made from polyethylene is that they are made by the blow method but are not reinforced at the ends or by top plates, etc.
A third important feature is that all plastic beer barrels hitherto manufactured have simply been copied from existing wooden or other (metal) barrels so that no manufacturer has allowed for the special demands made of a plastic beer barrel.
Before delving more deeply into this important point of differentiation, reference will be made to other known plastic beer barrels.
The first known beer barrel has the typical shape of a wooden barrel and is a copy thereof. The two ends are outwardly curved but at their ends they have a bent recess intended to form what might be termed a grip edge. Beer residues can collect in the cavity. Economically the barrel has a relatively unfavorable shape resulting in beer residue which makes it also difficult to clean. Apart from this, the barrel contracts or expands because of the normal thermal expansion of the synthetic material depending upon the temperature of the liquid or the temperature of the ambient medium. This is unacceptable as regards standardization of quality. The barrel and therefore its contents vary. This barrel also has a ring and a bung closure of different materials. Thus, the barrel is not homogeneous entirely and leakage may occur because of the different thermal properties. There was fitted a plate and a ring to try to obviate this but practice has shown that barrels made in this way can leak.
A second plastic barrel is of the traditional shape but has welded ends. The barrel has a flat end, which is very poor as a gripping edge and although it is made of plastic material it is very heavy because of the use of a solid end. Moreover because of the abrupt transition from the curvature of the body to the flat end, the barrel has an unequal wall thickness and the same disadvantage of deformation in the event of thermal expansion.
A third plastic barrel is a modification of the last mentioned barrel, and has inwardly curved ends and welded ends or edges. Apart from the normal deformation due to thermal expansion, the pressure of the CO may cause the blown barrel ends to curve out, resulting in an appreciable change of volume. Also, iron or steel tubes are provided to save material in the plastic parts forming the ends and integrally welded to the barrel body. Because of the difference between the coeflicients of expansion of the plastic and the steel, the latter expanding much more, stresses and cracks may occur in the plastic material so that the barrel becomes quite unusable. In this case as well beer residues remain in the barrel.
Lastly, there is a plastic beer barrel which has no welded ends nor roll edges while the roll bands are formed by bending the barrel body and are produced during the blowing process so that there are still beer residues in the barrel, and the latter does not roll satisfactorily. Moreover the ends are not protected and there is also the same objection as regards changes in shape and hence volume.
The object of the present invention is to obviate these disadvantages and the invention is based on the discovery that various articles subject to high pressures on both the inside and outside can retain a spherical shape imparted to them despite thermal expansions and contractions. The spherical shape is the only one which gives this advantage.
A pressure container and more particularly a beer barrel based on this spherical shape and constructed entirely of plastic has none of the disadvantages of the wooden, aluminum, steel or known plastic Containers.
In order that the invention may be more readily understood, the barrel according to the invention, will be described hereinbelow by way of nonlimitative example, with reference to the appended drawing, wherein:
FIGS. 1 to 4 show a first embodiment of a barrel and FIGS. to 8 show advantageous variations thereof.
This pressure container is characterized essentially in that it comprises a body 1 of spherical shape produced by a blowing, pressing, injection moulding, casting, centrifugation operation and having a substantially uniform thickness and two identical end parts 2 made in the form of spherical segments and connected to the spherical body so that the resultant assembly has the shape of a sphere internally while externally it has the conventional shape of a barrel.
The body 1 and the two end parts 2 are constituted of plastic material.
Each end part 2 is so shaped as to comprise a peripheral rim 3 and supporting elements or legs 4 for resting on the ground or a base, so that such ends form protective casings while the ribs 3 serve as grips and rolling surfaces.
The ribs 3 also increase the strength, particularly on dropping.
In order to give the container high elasticity so that it can appropriately absorb shocks and also to make the article as light as possible, hollow prefabricated sheaths or tubes 5 of the same plastic material as the ends are included therein during manufacture.
The polyethylene of the end is very initimately connected to the tubes of the same material and gives a very lightweight unbreakable and sealing-tight system.
The advantages of these containers may be summarized as follows:
(1) The shape does not change either by expansion, or contraction, while since any change of volume can be calculated in advance it remains within acceptable limits.
(2) As a result of the shape of the ends any high stresses in the event of impact forces may be resisted by these specially designed ends.
(3) The protection provided by the end parts in the form of spherical segments extends over a considerable part of the spherical body.
(4) The barrels can be readily placed one above the other and stacked as a result of the shape of the end parts.
(5) Because of the relatively high modulus of elasticity of the plastics used, impact forces will not result in any deformation or breakage resulting in any permanent and unacceptable changes of shape.
(6) The barrels can be completely emptied and leave no beer residue, and can readily be cleaned.
(7) There cannot be any dripping at the bung ring because of the absence of different materials.
(8) The barrels are very light and can be easily handled.
FIGURES 5-8 relate to the manufacture of a barrel made of polyester reinforced with glass-fiber. 1 and 1 designate the two hemispheres which are connected together for the obtention of the spherical body and 2 -2 are the end-pieces.
The pieces 1 1 are assembled by a gluing operation of joints shown in FIG. 17.
The joint for the sphere may occupy another position than represented. A characteristic of the pieces 2 2 is that a wall is formed of a flat extremity 57 to which is connected a substantially cylindrical portion 58 provided with a truncated portion 59 ending in a cylindrical portion 60.
The truncated portion 59 comes into contact in 61 and 62 with the half-sphere to which it is adhesively secured.
Each element 2 -2 is provided with a rolling ring 63 of plastic or rubber which is inserted and adhesively secured to portion around the periphery thereof.
The thickened portions 64 of the bung-holes are formed during a compression step or they may be constituted by separate elements.
The elements 2 -2 are provided with openings 65 which serve as a water outlet and also as gripping elements.
What I claim is:
1. A pressure container comprising a spherical body of plastic material having a substantially uniform wall thickness, and two end parts mounted in direct contact on said spherical body to substantially enclose the same, said two end parts having outer surfaces which define an elongated barrel shape for the container, said end parts having mating edges secured together along a great circle of the spherical body, each end part including an end cylindrical portion with an end flange disposed perpendicular to the axis of the cylindrical portion and defining an opening thereinto, a truncated cone portion extending in widening fashion from the cylindrical portion, said cone portion having an inner surface in direct engagement with the spherical body, and a second cylindrical portion extending from the cone portion and having one of said mating edges, said second cylindrical portion having an inner surface at said mating edge in direct engagement with the spherical body, the second cylindrical portion and the cone portion defining a hollow space with the spherical body, and annular rings on the second cylindrical portions of said end parts adjacent the junctions thereof with the cone portions such that the rings are supported on the end parts in the region of the hollow spaces which furnish flexibility for said rings.
2. A container as claimed in claim 1 wherein said spherical body is constituted by two joined hemispherical parts.
3. A container as claimed in claim 1 wherein said end cylindrical portions of the end parts are provided with inclined openings for the outlet of liquid between the outer surface of the spherical body and the inner surfaces of the cylindrical portions of the end parts.
4. A container as claimed in claim 1 wherein said end parts are also constituted of plastic material.
References Cited UNITED STATES PATENTS 1,909,028 5/1933 Waite.
2,033,268 3/1936 Widman.
2,250,749 7/ 1941 Cornelius.
2,519,375 8/1950 Jargstorif et al. 26489 2,620,963 12/1952 Hagopian 22914 X 2,744,043 5/1956 Ramberg 220 2,983,403 5/1961 Mauser 22066 X 3,138,507 6/1964 Wiltshire 22083 X 1,441,674 1/1923 Foster et al. 220 3,181,589 5/1965 Phelps 220-9 X-R 3,294,271 12/1966 Armbruster 2205 THERON E. CONDON, Primary Examiner.
G. E. LOWRANCE, Assistant Examiner.