| 摘要 |
<p>A method for closing thermoplastics film tubes, closed at one side and filled with sensitive material in dust form, to form a bag involves (a) gathering the open end, (b) deforming the obtained closure region while softening using hot pressing or ultrasound, (c) sealing by ultrasonic welding in the obtained stable, tensile stress-relieved closure region, while plasticizing along a separating line and (d) separating the bag. A method for closing plastics film tubes, closed at one side and filled with sensitive material in dust form, where at least the open end has a coating of thermoplastics (A) (at least on the inside), to form a bag involves: (a) gathering the open end to form a loose closure region; (b) deforming this region while softening (A) using hot pressing or ultrasound, to form a dimensionally stable, tensile stress-relieved closure region; (c) sealing the bag by ultrasonic welding in this region while plasticizing (A) along a separating line, where plasticization causes dust to be melted and bonded within the plastics structure; and (d) separating the bag. Independent claims are included for: (1) corresponding bag closure apparatus, having (i)pressing punch(es) (1) and ultrasonic sonotrode(s) (2) movable toward each other, the punch being a negative image of the sonotrode surface and the punch and/or sonotrode having an exchangeable surface, (ii) a holder for the open end of the bag, (iii) a device for gathering and applying pressure in the region betewen the punch and sonotrode and (iv) sonotrode-anvil combination(s), obtainable by exchanging the surface of the punch and/or sonotrode; and (2) apparatus for closing and separating a thermoplastics tube, filled via a filling pipe, closed at one end and having the open end fixed to a tube reservoir fixed above the filling pipe, comprising (i) at least two mold parts located at opposite sides of the open tube end, at least one of which is a sonotrode (2) and at least one of which is has an exchangeable surface, (ii) devices for applying pressure and (iii) sonotrode-anvil combination(s), obtainable by exchanging the surface of a mold part.</p> |
