Drum for chemical or electrolytic surface treatment of batches of mass produced components in aqueous solutions is made of two different grades of polyethylene with different molecular weights

摘要

The drum shell (3) as a self-contained unit is made of a polyethylene with a molecular weight differing from that of the polyethylene used for the two end walls (6) constituting complementary elements rigidly attached to the shell. Preferred Features: The polyethylene used for the shell (3) has a higher molecular weight than the polyethylene used for two end walls (6). The polyethylene used for the shell is an ultrahigh molecular polyethylene with a mol mass from 1000000 to 8000000 g.mol-1 , while the material of the end walls is a high molecular polyethylene with a mol mass from 300000 to 800000 g.mol-1. The shell (3) consists of several sections formed by plate-shaped rectangular, generally plane perforated elements welded to one another along their edges. Alternatively it is formed from a single plate element of ultrahigh polyethylene which is divided into sections and provided with edge welds. The end walls are attached to the shell by friction or extrusion welding processes, with use of ultrahigh molecular polyethylene respectively as a truncated friction cone or an added welding material. As a further alternative, the end walls can be attached to the shell by means of screws. The drum (1) is provided with tumbler bars (4). The drum lid (2) can incorporate one or more tumbler bars.