Device for sealing lengths of filter paper

Abstract

A device for sealing filter bags for products for infusion, where each filter bag is made from a flat web (1) of filter paper and has applied to it a tag (1b) and a tie string (1a) connecting the tag (1b) to the filter bag itself, comprises at least: a sealing sonotrode element (3) positioned so that it faces a first path (P) along which the flat web (1) is fed and so as to seal the string (1a), which is arranged according to a defined pattern, and the tags (1b) to each other and to the flat web (1) of filter paper'.; drive means (4) for imparting to the sealing sonotrode means (3) a defined motion towards and away from a sealing position; the drive means (4) in turn comprising first means (5) acted upon by the sealing sonotrode element (3) and designed to apply a predetermined force (F) to the sealing sonotrode element (3) itself; second means (6) for opposing the action of the first means (5), that is to say, for reducing its intensity, and third control means (7) for disabling the second means (6), during predetermined steps of passing the filter bag components under the sealing sonotrode element (3), so as to permit a predetermined sealing contact.

Dependencies are inferred from the claim text.