Method and line for the high-speed packaging of filter bags containing an infusion product

Abstract

A method and a line for the high-speed packaging of filter bags (1) containing an infusion product comprises at least three successive operating steps whereby: the filter bags (1) are wrapped in a continuous protective tubular envelope (2) by sealing a continuous V-shaped folded strip (3) along a longitudinal sealing line (5) and transversal sealing lines (6); the tubular envelope (2) is cut into lengths; and the filter bags (1), individually wrapped in respective envelopes (2), are placed in cartons. In the method and line (26) according to the invention, 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 same transversal seal (6).

Description

BRIEF DESCRIPTION OF THE DRAWINGS

The advantageous aspects of the invention are more apparent from the detailed description which follows, with reference to the accompanying drawings which illustrate preferred embodiments of the invention provided merely by way of example without restricting the scope of the inventive concept, and in which:

FIG. 1 is an elevation view of an automatic machine equipped with a packaging line according to the invention;

FIG. 2 is an elevation view of a part of the machine of FIG. 1 and shows a packaging line integrated in the machine;

FIG. 3 shows the packaging line of FIG. 2 in a plan view from above;

FIG. 4 is an assembly view of a wrapped filter bag made by the machine illustrated in the drawings listed above.

Claims

1. 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).

2. The method according to claim 1, wherein the step of making the seals (5; 6) is followed 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.

3. The method according to claim 2, wherein the feeding step comprises a step of slowing down the filter bags (1) so that, at a predetermined position, the speed of the filter bags (1) is synchronized with that of the continuous target strip (3) of material.

4. The method according to claim 3, wherein the step of slowing down the filter bags (1) is performed by at least one pair of bilateral spring pins (9) transversal to the wings (4) of the folded V-shaped strip (3), designed to oppose each other in a direction transversal to the strip (3) and having, interposed between them, said continuous strip (3) of material from which the envelopes (2) are made.

5. The method according to claim 4, wherein the slowing down step is performed at least by locally narrowing the end edges (10) of the folded wings (4) of the continuous strip (3) of material from which the envelopes (2) are made.

6. The method according to claim 5, wherein the local narrowing is accomplished by contact between two disc-shaped members (11) mounted tangent to each other on one end of each of the spring pins (9), with the continuous strip (3) of material from which the envelopes (2) are made passing between them.

7. The method according to claim 2, wherein the feeding step is performed while holding the filter bag (1) by its head (12) and keeping the filter bag (1) in a flat condition firmly in the same plane as the head (12).

8. The method according to claim 7, wherein the filter bag (1) is kept firmly in the flat condition by jets of air under pressure blown onto it by nozzles (13) mounted on two parallel shoulders (14) between which at least the bottom portion (15) of the filter bag (1) passes.

9. The method according to claim 1, comprising a step of gradually squeezing the filter bags (1) in order to redistribute the infusion product inside each filter bag (1), moving at least a part of it away from the bottom portion (15) of the filter bag (1).

10. The method according to claim 9, wherein the squeezing step is performed by a plurality of roller pairs (16) positioned one after the other, the rollers (16) of each pair being mounted on each side of the strip (3) of material from which the envelopes (2) are made; the spacing between the rollers (16) of each pair gradually decreasing from one pair of rollers (16) to the next in the feed direction (17) of the strip (3) of material from which the envelopes (2) are made.

11. The method according to claim 10, wherein the rollers (16) have a rigid structure.

12. The method according to claim, wherein the squeezing step precedes the step of heat sealing the continuous strip (3) of material from which the envelopes (2) are made.

13. The method according to claim 1, comprising, prior to the step of cartoning the filter bags (1), a step of synchronizing the feed speed of the filter bags (1) with cartoning means (18), said synchronizing step being designed to maintain a continuous flow of filter bags (1) fed to the cartoning means (18).

14. The method according to claim 13, wherein the step of synchronizing the speed is performed by two continuous conveyor belts (19, 20) having conveyor sections (21, 22) placed face to face and in contact with each other, the filter bags (1) passing between the conveyor sections (21, 22) being accelerated or decelerated according to their instantaneous speed and relative to the instantaneous position of the cartoning means (18) located further on in the feed direction (17) of the strip (3) of material from which the envelopes (2) are made.

15. The method according to claim 14, wherein the cartoning step follows a step of inspecting each filter bag (1), during which, if the latter conforms with specifications, an output signal is generated to enable the cartoning means (18) to carton the passing filter bag (1) or, if it does not conform with specifications, to inhibit cartoning so that the filter bag (1) is allowed to move past the cartoning means (18) towards a reject container further downstream.

16. A line for the high-speed packaging of pre-formed filter bags (1) containing metered quantities of an infusion product, comprising at least three consecutive working sections (23, 24, 25), in the first of which (23) 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 working section (24), the flattened tube being cut into predetermined lengths; and in the third working section (25) the filter bags (1), wrapped in the envelopes (2), being placed in cartons; wherein the first section (23) of the line (26) includes two separate and successive sealing units (27, 28) designed to make each transversal seal (6) on the continuous strip (3) in two consecutive steps, the first unit (27) making the first part of the seal and the second unit (28) completing it.

17. The line according to claim 16, wherein each sealer unit (27, 28) in the first working section (23) comprises a pair of sealing rollers (29) positioned on each side of and transversely to the strip (3) and pressing against each other.

18. The line according to claim 17, wherein each sealer unit (27, 28) in the first working section (23) is driven by an independent motor (30).

19. The line according to claim 18, wherein the drive motors (30) of the sealing units (27, 28) of the first working section (23) are driven in parallel with each other.

20. The line according to claim 17, comprising slowing means (9; 11, 52) designed to reduce the speed of the filter bags (1) fed above the strip (3) until they reach a predetermined position where they are synchronized with the speed of the continuous strip (3) of material from which the envelopes (2) are made.

21. The line according to claim 20, wherein the means for slowing down the filter bags (1) comprise at least one pair of bilateral spring pins (9) transversal to the wings of the folded V-shaped strip (3), said spring pins (9) opposing each other and have, interposed between them, the continuous strip (3) of material from which the envelopes (2) are made.

22. The line according to claim 21, wherein the spring pins (9) have at one end respective free turning disc-shaped members (11) tangent to each other and having, interposed between them, the continuous strip (3) of material from which the envelopes (2) are made.

23. The line according to claim 16, comprising means (13, 14) for keeping the filter bag (1) in a flat condition while the filter bag (1) is being fed above the continuous strip (3) of material from which the envelopes (2) are made, said means (14) being designed to keep the filter bag (1) firmly in the same plane as the head (12) which is in turn held by grippers (31) on a wheel (32) that operates in conjunction with the strip (3).

24. The line according to claim 23, wherein the means (13, 14) for keeping the filter bags firmly in the flat condition comprise two parallel shoulders (14), between which at least the bottom portion (15) of the filter bag (1) passes, and which comprise nozzles (13) that blow jets of air under pressure on the filter bag (1).

25. The line according to claim 24, wherein the shoulders (14) have the shape of a circular arc.

26. The line according to claim 16, comprising, upstream of the first working section (23), squeezing means (16) designed to redistribute the infusion product inside the filter bag (1), moving at least a part of it away from the bottom (15) of the filter bag (1), in such a way as to gradually reduce the thickness of the filter bag (1).

27. The line according to claim 26, wherein the squeezing means comprise a plurality of roller pairs (16) positioned one after the other on each side of the strip (3) of material from which the envelopes (2) are made; the spacing between the rollers (16) of each pair gradually decreasing from one pair of rollers (16) to the next in the feed direction (17) of the continuous strip (3) of material from which the envelopes (2) are made.

28. The line according to claim 27, wherein the rollers (16) have a rigid structure.

29. The line according to claim 16, comprising synchronizing means (19, 20) for synchronizing the feed speed of the filter bags (1) with cartoning means (18), in such a way as to maintain a continuous flow of filter bags (1) fed to the cartoning means (18).

30. The line according to claim 29, wherein the speed synchronizing means comprise two continuous conveyor belts (19, 20) having conveyor sections (21, 22) placed face to face and in contact with each other, the filter bags (1) passing between the conveyor sections (21, 22) being accelerated or decelerated according to their instantaneous speed and relative to the instantaneous position of the cartoning means (18) of a third section (25) located further on in the feed direction (17) of the strip (3) of material from which the envelopes (2) are made.