High pressure drum cover

This invention relates to a drum cover and, more particularly, to a cover for a high pressure drum.

In one form of conventional shipping and storage container, a drum comprises a tubular container having an open end with a cylindrical connecting bead at the open end. The connecting bead may be provided by a metal connecting ring rolled onto the side wall or a plastic connecting ring molded directly to or otherwise adhered to the side wall. Alternatively, the side wall may be of molded plastic construction with an integral connecting bead.

The conventional drum includes a removable cover for closing the open end of the tubular side wall. A typical cover includes a central circular wall with a peripheral connecting flange receivable on the connecting bead so that the circular wall closes the open end of the container. A locking band secures the cover on the drum. While such a container may be used for storage purposes, often the containers must be lifted by lifting equipment. Advantageously, the drum should be designed to accommodate parrot beak drum lifting devices. If the cover is not of sufficient thickness, the drum may not pass a typical parrot beak test. Typically, such a cover includes circular channels or rings formed in the circular wall providing a corrugated or wave-like appearance.

When used in shipping applications, the containers are often designed to meet certain requirements. These requirements may comprise drop ratings, pressure ratings or the like. One such rating is a liquid U.N rating for Z1.2/50/S/USA/GBC. In this rating, the 1.2 refers to the specific gravity of the contents of the container. The numeral 50 refers to the kPA rating of the container. With such a rating, a container, such as a drum and cover, must be capable of passing a hydro test in which the contents of the drum is filled with pressurized water. A conventional drum cover when subjected to a hydro test might fail as the pressure causes expansion of the cover which may lift the peripheral connecting flange away from the connecting bead.

The present invention is directed to solving one or more of the problems discussed above in a novel and simple manner.

In accordance with the invention, there is provided a cover for use with a tubular container for satisfying high pressure requirements.

Broadly, in accordance with one aspect of the invention, there is disclosed a unitary cover for use with a tubular container having an open end with a cylindrical connecting bead at the open end. The unitary cover comprises a central circular wall. A concentric ring region surrounds the central circular wall. An annular flange comprises a downwardly opening U-shaped channel receivable on the cylindrical connecting bead. A cylindrical connecting wall connects an inner edge of the annular flange, inwardly of the U-shaped channel, to the connecting ring region.

It is a feature of the invention that the annular flange and the connecting wall have a greater wall thickness than the circular wall and the concentric ring region.

It is another feature of the invention that the concentric ring region comprises first and second concentric rings disposed between the connecting wall and the central circular wall to define a generally corrugated structure.

It is another feature of the invention that the concentric ring region is connected at a central portion of the connecting wall.

It is still another feature of the invention that the connecting wall extends downwardly from the concentric ring region to back up the drum open end.

There is disclosed in accordance with another aspect of the invention, a unitary cover for use with a tubular container having an open end with a cylindrical connecting bead at the open end. The unitary cover comprises a central circular wall. An expansion region surrounds the central circular wall. An annular flange has three concentric cylindrical walls defining an E-shaped wall. An outermost and middle cylindrical walls define a channel receivable on the cylindrical connecting bead. An innermost cylindrical wall defines a hinge and is connected to the expansion region.

It is a feature of the invention that the annular flange has a greater wall thickness than the circular wall and the expansion region.

It is another feature of the invention that the expansion region comprises first and second concentric rings disposed between the annular flange and the central circular wall to define a generally corrugated structure.

It is still another feature of the invention that the expansion region is connected at a central portion of the innermost cylindrical wall.

It is still another feature of the invention that the innermost cylindrical wall further comprises a downwardly extending backup wall extending downwardly from the expansion region to back up a drum open end.

It is yet another feature of the invention to provide a pair of bung openings in the central circular wall.

It is yet another feature of the invention that the annular flange is a diameter to be received on a tubular container having a connecting bead in the range of 14″ to 23″.

It is still another feature of the invention that the cover comprises a unitary wall element of synthetic resin.

Further features and advantages of the invention will be readily apparent from the specification and from the drawings.