Plate filter insert - has concertina-folded sheet material where outer edges are held in place against frame to prevent leakage of unfiltered air

摘要

In plate filter insert with concertina-folded sheet material gas filter incorporates a sheet of concertina-folded material located within a frame. Strip of material of unalterable length extends over the entire length of one surface of the concertina-folded filter material. Peaks of filter material and the strip with which they are in contact are connected. Strip material and the stiffness of the folds together prevent the strip bending vertical to the filter plane. USE/ADVANTAGE - Arrangement ensures that the filter material is inserted square within the frame so that the outer edges are held in place against the frame to prevent leakage of unfiltered air around the sides to the filtered side. A suitable frame assembly with concertina-folded filter material (3) incorporates a strip (14) of non-extending material on the back (15) of the filter insert. Some of the filter peaks (15) are joined to the strip (14). The stiffness of the folds (16) in a direction vertical to the filter plane ensures that the strip (14) cannot be dislodged. The strip is made of a pliable material and bears a coating on the face in contact with the filter material with which it is joined.