Abstract: A method and device for testing the quality of a sheet-like element comprising a membrane are presented. The quality test is limited to a part-area of the sheet-like element. A useful material is fed to one side of the sheet-like element via an outlet orifice corresponding to the part are to be tested. The method can be used in the production of large-area membranes or membrane/electrode units (MEU) provided for use in fuel cells. The quality test can take place in a simple way even during production of these sheet-like elements. Faults during production can be detected at an early stage and the production parameters changed accordingly. In the case of testing an MEU for a fuel cell, fuel gas can be applied to one side of the MEU in a punctiform manner. Oxygen of the ambient atmosphere located on the other side can serve as an oxidation gas.

Abstract: A method for fabricating a plastic electrical insulator having a fiberglass-reinforced plastic core rod and a plurality of insulator discs disposed thereon. The insulator discs are formed of a plastic molding compound which is especially suited for outdoor use. In accordance with the invention, the insulator rod is disposed in, and passes through, a mold which, when closed, is filled with the plastic molding compound for forming the insulator discs. The separation plane of the mold is situated near the outermost edge of each disc. Subsequent insulator discs are individually formed so as to partially overlap a previously molded insulator disc.