Patent ID: 7434374

Claim:
A method for the high-speed packaging of pre-formed filter bags ( 1 ) containing metered quantities of an infusion product, comprising at least three steps, in the first of which the filter bags ( 1 ) are wrapped in a protective tubular envelope ( 2 ) formed by a longitudinal seal ( 5 ) and a transversal seal ( 6 ) making a flattened tube from a continuous strip ( 3 ) of envelope ( 2 ) material folded into a V shape with wings ( 4 ) between which the filter bags ( 1 ) are suitably placed at regular intervals from each other; in the second step, the tube being cut into predetermined lengths, each containing one filter bag ( 1 ) wrapped in an envelope ( 2 ); and in the third step the filter bags ( 1 ), wrapped in the envelopes ( 2 ), being placed in cartons; wherein the transversal seal ( 6 ) is made in two successive steps as the continuous folded strip ( 3 ) moves through two separate consecutive sealing stations ( 7 , 8 ), the first station ( 7 ) making a part of the transversal seal ( 6 ) and the second station ( 8 ) completing the rest of the same transversal seal ( 6 ); the step of making the seals ( 5 ; 6 ) being preceded by a feeding step in which the filter bags ( 1 ) are released between the wings ( 4 ) of the continuous strip ( 3 ), said feeding step being implemented by releasing the filter bags ( 1 ) in a direction substantially tangential to the strip ( 3 ) and at a speed higher than the speed at which the strip ( 3 ) advances; said feeding step being performed while holding the filter bag ( 1 ) by a respective head ( 12 ) and keeping the filter bag ( 1 ) in a flat condition firmly in the same plane as the head ( 12 ) by jets of air under pressure blown onto the filter bag by nozzles ( 13 ) mounted on two parallel shoulders ( 14 ) between which at least the bottom portion ( 15 ) of the filter bag ( 1 ) passes.