PROCESS AND DEVICE FOR FOLDING BACK THE MEMBRANE OF A PRESSURE FILTER FOR SUSPENSIONS
A pressure filter for suspensions comprises a boiler-shaped outer shell (1) closed by a lid (11) which moves coaxially with the outer shell, a filter element (15) which projects from the lid, and a membrane (5) which can be folded back arranged coaxially between the outer shell and the filter element. The membrane folds back outside the outer shell when the filter is opened and folds back inside the outer shell when the filter is closed. When the filter is closed, a partial vacuum with respect to the ambient pressure is created and the membrane is deformed by external influences, thus preventing the formation of a single crease (21), which would project laterally above the edge of the outer shell (1), until the membrance forms a triple or multiple crease, which does not project laterally above the edge of the outer shell.