Method for the manufacture of a bung barrel with a side wall, bottom and cover.

The invention relates to a method for producing a bung barrel by way of blow molding, wherein the barrel sidewall, barrel bottom and barrel top are integrally molded from thermoplastic material, wherein the barrel top, at least one bunghole is fitted with bung hole collar and wherein in the region of the transition between the barrel sidewall and the barrel top for manipulation purposes an L-ring is disposed. L ring means that the ring has an inverted L-shaped cross section in upright bung barrel, whose L-foot points outwards. L-legs and L-foot may be connected at right angles or at a different angle to each other. The L-ring may be molded in the blow-molding or pre-formed and welded.

Tight head drums which are made in the manner described, are used as containers for various purposes and for the storage and transport of a wide variety of liquid substances. The practice requires increasingly tight head drums, which can be as completely emptied with little remaining in the bung barrel residual amount. For the purpose of emptying such a plugged vessel is brought into a Entleerungskippstellung Angled Faßachse or asked to speak with vertical Faßachse upside. The last-mentioned position is referred to in the invention as inverted, emptying position. It is at least taken at the end of emptying process. In general, two bung holes are provided, one. For the filling, one for the emptying The filling can also be done through both bung holes. Emptying through a defined bunghole. It is understood that the evacuation is carried out so that the leakage of the liquid air can penetrate into the plugged vessel. The bung barrel can be to also equipped with appropriate facilities. The bunghole collar is externally usually provided with a thread for screwing on a closure cap.

Within the known measures of which the invention is based (GB-A-2201936, DE-U-86 28 811) the bunghole and bunghole collar are formed in the blow molding. The bunghole collar can be configured as a protuberance that is formed during the blow molding and the top head is cut off after molding, so as to form from the hat-shaped protuberance of the bung hole collar. Both during the emptying of a bung barrel by a Enleerungskippstellung as well as during emptying of a bung barrel on the inverted, emptying position is a troublesome large residual amount in the bung barrels produced by the known methods. A full evacuation by mere expiry, after which in a prepared by the known measures plugged vessel one disturbing large amount of liquid to be emptied no longer exists, is not possible. If such a bung barrel can be reused, are filled esp. With another liquid substance, the remaining quantity must be laboriously removed and discarded. The cleaning of Faßinnenraumes is difficult when there is still a disturbingly large residual amount in Faßinnenraum.

The invention has for its object to provide a method of the kind described in the introduction with which a spigoted barrel can be manufactured in a simple manner, wherein in the inverted, emptying position, a full emptying without disturbing residual amount is possible.

To achieve this object, the invention teaches that the bunghole is arranged in a lowest in the inverted, emptying position area of ​​the barrel top, that the bung hole collar is inserted in the form of a pre-formed component in the blow that the component is welded with the blow molding of the barrel top and that the bunghole is without a surrounding formed only after the removal of the bung barrel by drilling. The preformed component generally consists of a thermoplastic plastic material which is easily weldable to your plastic from which the barrel sidewall, barrel bottom and the barrel top which are constructed. Preferably the process is carried out so that a welding flange provided with a bung hole collar on this welding flange is welded to the barrel top. According to a preferred embodiment of the invention is a bunghole, matches the diameter of the inner diameter of the bunghole collar, formed by drilling. but also it will not interfere when the inside diameter of the bung-hole collar is slightly larger or slightly smaller than the borehole diameter. A method for manufacturing a bung barrel, in which the bung is disposed in a deepest position in the inverted, emptying the region of the barrel top, is generally known (US-A-4767021). - The invention is based on the realization that in the area between the barrel top and bunghole collar for Faßinnenraum out of rheological reasons the bunghole surrounding, more or less pronounced bulge occurs when, the bunghole collar by means of a protuberance is formed as described above, or when the bung hole collar is formed from the thermo-plasticized tubing from which the barrel is blown, this more or less pronounced ridge has not been recognized, little noticed or taken as not interfere in purchase. The bead actually interferes little when the bunghole connected to the barrel casing and the plugged vessel is brought to discharging to Entleerungskippstellung. However, modern practice requires the full emptying on the inverted, emptying position. Then, the peripheral bead forms a wall, behind which, depending on the bead thickness is a very significant, disturbing large residual amount of liquid to be emptied accumulates and accumulates. A full emptying is not possible in such a case. According to the invention, such a peripheral bead is avoided because the bung hole is formed by drilling. The term drilling is intended to express that the hole is cut. These can be operated with a conventional drill, a correspondingly guided mechanical knife, a laser beam used as a knife or the like.

Specifically, frames are made of the invention several possibilities for further development and design of the inventive method. Thus, an embodiment is characterized in that the deepest in inverted, emptying position area of ​​the barrel top is placed in the center of the barrel top. Another embodiment is characterized in that the deepest position in inverted, emptying the region of the barrel top is formed as a circumferential shallow groove at the edge of the barrel top. But there is also the possibility to conduct the process so that the barrel top is formed as an inclined plane, and the well is located in the deepest in inverted, emptying position area of ​​the inclined plane.

Characterized by simplicity in terms of process technology is an embodiment of the method, wherein the preformed component is inserted into the blow mold to surround the blow hole formed during the blow molding, which is made smaller than that corresponding to the inside diameter of the bunghole collar, and that the region of the barrel top is removed between the blowhole and bunghole collar only after the removal of the bung barrel by drilling. Also in this way the bunghole is without a surrounding formed.

As already mentioned a bung barrel is generally provided with two bungholes. The second bung is arranged in the manufactured by the inventive bung barrel outside the deepest in inverted, emptying position region of the barrel top. According to the invention the second bunghole is expediently designed as a hole and welded the bunghole collar with a weld. When preparing a bung barrel with two bung holes, it is recommended that the pre-formed components for both bung holes into the blow mold are inserted. In the present invention also provides a method, the special importance is belongs, and which is characterized in that the bung-hole is placed in a deep in the inverted, emptying position area of ​​the barrel top, that the bunghole is without a surrounding only after the removal of the bung barrel formed by drilling, that the bunghole collar is sealed with an extension which protrudes into the Faßinnenraum and their external diameter is fitted in the hole diameter in the barrel top and that full evacuation holes are located in the extension.

In the following the invention is explained in detail by way of in each case only one exemplary embodiment illustrative drawings. Shown in a schematic representation<dl id="dl0001"><dt>Fig. 1</dt><dd>an axial section through an inventively produced bung barrel, </dd><dt>FIG. 2</dt><dd>in comparison with FIG. 1 greatly enlarged scale the detail AA from the subject matter of FIG. 1,</dd><dt>Fig. 3</dt><dd>In the left part of the further enlarged detail BB from the article of Fig. 2 and in the right part, a corresponding representation of a known embodiment,</dd><dt>Fig. 4</dt><dd>corresponding to Fig. 1, another embodiment of a bung barrel according to the invention.</dd><dt>Fig. 5</dt><dd>corresponding to FIG. 1 a further embodiment,</dd><dt>Fig. 6</dt><dd>the side view of yet another embodiment, partially in vertical section,</dd><dt>Fig. 7</dt><dd>the enlarged section A from the object according to FIG. 6 and</dd><dt>Fig. 8</dt><dd>a plan view of the article of Fig. 7.</dd></dl>

The bung barrel illustrated in Figures 1 to 5 has a barrel sidewall 1, a barrel bottom and a barrel top 3. 2 the bung barrel has been formed in one piece by means of blow molding of thermoplastic material. The barrel top 3 has in the exemplary embodiment two bungs 4 with bunghole collar 5. arranged in the transition area between the barrel sidewall 1 and barrel top 3 is an L-ring 6 for manipulation purposes. In particular, from a comparative Betrachung of FIGS. 1 and 2 takes it that the bunghole 4 is designed as a borehole, which is disposed in a deepest position in the inverted, emptying the region of the barrel top third In the inverted, emptying position would be upside down in Figs. 1 and 4 and 5 barrels of vertical axis shown. The bunghole collar 5 is designed as a pre-formed component with weld. 7 The preformed member is welded from the outside with the welding flange 7 to the barrel top third It may also consist of plastic and has an inner diameter as closely as possible matches the hole diameter. - Through the borehole and the design described the formation of a bead is avoided, which occurs when the bung-hole collar 5 is formed during the blow-molding from the thermoplasticized hose which is inflated in the blow mold to the bung barrel 1, 2, 3, or when the bunghole collar 5 is made as a protuberance in the blow molding. Reference is made to FIG. 3. In FIG. 3 the left can be seen as an enlargement of the subject of FIG. 2, the embodiment of the invention, in which Fig. 3 right the bead 8. As described in the known embodiments already explained, makes this bead 8 in the inverted, emptying position as if a dam who holds a disturbing amount of the emptied liquid substance.

In the embodiment of FIG. 1 is the deepest in inverted, emptying position area of ​​the barrel top 3 is in the center of the barrel top 3. In the embodiment of FIG. 4, the configuration is devised such that the deepest in inverted, emptying position area of ​​the barrel top 3 as a circumferential groove 9 am edge of the barrel top is performed. 3 In Fig. 5 it can be seen that the barrel top is designed as an inclined plane 3 and that the left bung 4 is arranged in the deepest position in inverted, emptying the region of the inclined plane. In the embodiment, the bung barrel 1, 2, 3 and a second bunghole has always 4. The second bunghole 4 is designed as a borehole and the bunghole collar 5 is welded as a pre-formed component with a weld. 7

The embodiment according to FIGS. 6 to 8 differs from the embodiment according to FIGS. 1 to 5 characterized in that the bung-hole collar 5, which is a pre-formed component, an outwardly projecting welding flange does not have. The arrangement is rather made so that the bunghole collar 5 an extension 5a has, projecting into the Faßinnenraum and their outer diameter in the borehole diameter and thus fit in the diameter of the bunghole 4. The bunghole collar 5 is welded to the extension 5a in the barrel top. 3 In the extension 5a full emptying holes 5b are arranged. The barrel top 3 has, based on the emptying of the tilted or 180 ° C twisted barrel, a lowest point and the deepest the bunghole 4 of the bung hole collar. 5 Full draining holes means that as it faßinnenraumseitig in the extended bunghole collar 5a these holes are arranged 5b that touch the inner surface of the barrel top. 3 Reference is made particularly to Figs. 7, which shows that a very complete emptying is possible.