Method for the production of a filter element

Abstract

A process for production of a filter element includes forming a cylinder by bending a flexible filter mat having a series of folds adjacent to one another at least in individual end areas on longitudinal end edges thereof such that the end areas overlap with end edges being aligned along a length of the cylinder, joining the end areas on an exterior of the cylinder along a junction seam, and reversing the cylinder inside out such that an annular filter element is formed with the junction seam on an interior thereof.

1 . A process for production of a filter element, comprising the steps of:
 forming a cylinder by bending a flexible filter mat having a series of folds adjacent to one another at least in individual end areas on longitudinal end edges thereof such that the end areas overlap with end edges being aligned along a length of the cylinder;   joining the end areas on an exterior of the cylinder along a junction seam; and   reversing the cylinder inside out such that an annular filter element is formed with the junction seam on an interior thereof.   
   
   
       2 . A process according to  claim 1  wherein
 after reversal of the cylinder, the annular filter element is placed within a fluid permeable support tube with tops of folds immediately adjacent the junction seam engaging an inner surface of the support tube.   
   
   
       3 . A process according to  claim 1  wherein
 inner surfaces of the cylinder are in contact as the end areas are joined by fusion to form a fusion seam.   
   
   
       4 . A process according to  claim 1  wherein
 the end areas extend directly from folds located on an exterior of the annular filter element after reversal of the cylinder.   
   
   
       5 . A process according to  claim 1  wherein
 the flexible mat comprises metal-free, plastic-supported filter mats.   
   
   
       6 . A process according to  claim 1  wherein
 dimensions are determined for the flexible filter mat allowing reversing of the cylinder after formation of an exterior fusion seam joining the end areas.   
   
   
       7 . A process according to  claim 1  wherein
 a retaining device with retaining elements is placed on the annular filter element to overlap folds adjacent to the junction seam on surfaces of those folds remote from the junction seam.   
   
   
       8 . A process according to  claim 7  wherein
 after reversal of the cylinder, the annular filter element is placed within a fluid permeable support tube with tops of folds immediately adjacent the junction seam engaging an inner surface of the support tube; and   the retaining elements project radially inwardly from the inner surface of the support tube.   
   
   
       9 . A process according to  claim 8  wherein
 the support tube is a transfer-molded plastic with the retaining elements integrated therein.   
   
   
       10 . A process according to  claim 7  wherein
 the retaining elements are legs of a U-shaped clamping element that is inserted onto the surfaces of those folds.