| 摘要 |
An apparatus for packaging a substance in closed bags formed from two continuous ribbons of a thin fragile material in which the ribbons are sealed to each other as they pass downwardly between first and second pairs of horizontal nipping rollers. A bag open at the top is produced from a portion of the ribbons by sealing and is filled with a predetermined amount of the substance to be packaged. The top of the bag is subsequently sealed to close the bag after the ribbons have advanced downwardly a predetermined distance. These operations take place sequentially on successive portions of the ribbons as they advance toward the second pair of nipping rollers, forming a series of sealed bags. At least one of the first pair of nipping rollers has a generally smooth annular concave portion extending between the end portions thereof, while at least one of the second pair of nipping rollers has a generally cylindrical portion of reduced diameter extending between its end portions. Rotation of the rollers about their respective axes is controlled to advance the ribbons in a desired manner. The two ribbons approach the first pair of rollers generally horizontally from opposite sides. They pass over and partially around the rollers to the point of nipping engagement, from which they proceed downwardly toward the second set of rollers. The portions of the two ribbons above the first pair of rollers are tensioned away from those rollers to pull the ribbons into the concave portions, preforming the ribbons at that point and for a substantial distance therebelow into a generally tubular shape. A conduit for introducing the substance to be packaged into each of the open bags extends downwardly between the first pair of rollers.
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