Filter manufacturing apparatus

Abstract

The present invention relates to a filter manufacturing apparatus comprising: a feed path adapted to continuously feed a filter material along a longitudinal transport direction; a forming device connected to a terminating end of the feed path and adapted to form the filter material into a continuous filter body and to deliver the formed continuous filter body, the forming device including: a tubular element (8) adapted to allow the filter material to pass therethrough to form the filter tow material into the continuous filter body; and a steam generator (9) adapted to produce steam, the steam generator being in fluid communication with the tubular element to supply steam to the filter material; a drain channel (10) in fluid communication with the tubular element adapted to drain fluid from the tubular element; a valve adapted to open and close the drain channel so as to allow or block discharge of fluid from the tubular element.

Claims

1. A filter manufacturing apparatus comprising: a feed path adapted to continuously feed a filter material along a longitudinal transport direction; a forming device connected to a terminating end of the feed path and adapted to form the filter material into a continuous filter body and to deliver the formed continuous filter body, the forming device including: a tubular element adapted to allow the filter material to pass therethrough to form the filter tow material into the continuous filter body; and a steam generator adapted to produce steam, the steam generator being in fluid communication with the tubular element to supply steam to the filter material; a drain channel in fluid communication with the tubular element adapted to drain fluid from the tubular element; a valve adapted to open and close the drain channel so as to allow or block discharge of fluid from the tubular element.

2. The filter manufacturing apparatus according to claim 1, wherein the tubular element includes an inner peripheral surface adapted to be in contact with the filter material and wherein the drain channel has an end opened in the inner peripheral surface of the tubular element to drain condensed liquid from the interior of the tubular element.

3. The filter manufacturing apparatus according to claim 1, wherein the tubular element includes an inner peripheral surface adapted to be in contact with the filter material and a condensate chamber in fluid communication to the inner peripheral surface, and wherein the drain channel has an end opened in the condensate chamber to drain condensed liquid from the interior of the condensate chamber.

4. The filter manufacturing apparatus according to claim 1, wherein the drain channel includes a second end fluidly connected to a drain tank.

5. The filter manufacturing apparatus according to claim 1, wherein the valve is configured to open and close the drain channel at a predetermined frequency.

6. The filter manufacturing apparatus according to claim 1, wherein the forming device includes a pressure sensor apt to measure a pressure within the tubular element.

7. The filter manufacturing apparatus according to claim 1, wherein the tubular element comprises a plurality of separated tubular elements, the drain channel being in fluid communication with a first of the plurality of separated tubular elements in the longitudinal transport direction of the filter material.

8. The filter manufacturing apparatus according to claim 1, comprising: a plasticizer addition unit arranged upstream an inlet of the tubular element and adapted to spout a plasticizer to add the plasticizer to the filter material.

9. The filter manufacturing apparatus according to claim 1, wherein the tubular element comprises a tapered portion, so that its internal diameter decreases along the longitudinal transport direction.

Description

(1) The invention will be further described, by way of example only, with reference to the accompanying drawings in which:

(2) FIG. 1 is a schematic view of an apparatus for forming a filter according to the invention;

(3) FIG. 2 is a perspective view of a portion of the apparatus of FIG. 1;

(4) FIG. 3 is a further perspective view of a portion of the apparatus of FIG. 1;

(5) FIG. 4 is a schematic lateral view in section of an element of the apparatus of FIG. 1;

(6) FIG. 5 is a perspective view partially exploded of a different embodiment of the element of FIG. 4; and

(7) FIG. 6 is a perspective view partially exploded of the element of FIG. 5.

(8) Numeral 1 in FIG. 1 indicates an apparatus as a whole, for producing filter rods (not shown) or filters components, preferably for aerosol-generating articles.

(9) Apparatus 1 comprises a transport device 3 to transport along a transport or feeding direction filter material, for example cellulose acetate or filter tow. Further, the apparatus 1 includes an inlet unit 2 adapted to form a continuous stream or strip of filter material, moistened with a hardening fluid or plasticizer, such as triacetin. The filter material is fed to the inlet unit 2 by the transport device 3. The moistening of the filter material with plasticizer takes place in a plasticizer unit, not shown in the drawings and known in the art. The plasticizer unit is located upstream the inlet unit 2. Downstream the inlet unit 2, the apparatus includes a rod forming unit 4, arranged in series to the inlet unit 2 and adapted to receive the flow or band of filter material and to cause the hardening material to react to transform the filter material into a continuous axially rigid rod filter.

(10) Advantageously, the apparatus 1 further includes a wrapping unit 6, to wrap the hollow rod filter in a wrapping paper 90. Further, the apparatus may comprise a cutting unit 7, normally a rotating cutting head of known type, arranged downstream of the rod forming unit 4 and wrapping unit 6 and adapted to cut the hollow filter rod crosswise into filter segments (not shown). The desired length of the units in which the filter body is cut is for example obtained with the assistance of a measurer apparatus (also not shown). The cut units are made available in following processing steps or are buffered.

(11) Wrapping unit 6, transport device 3 and cutting unit 7 are known in the art and not further detailed below.

(12) The rod forming unit 4 comprises a tubular element 8, shown in an enlarged view in FIG. 4, adapted to receive the filter material saturated with hardening material, for example along the arrow 30 depicted in FIG. 4 which is the transport direction of the transport device 3, and to shape the filter material crosswise so as to transform it into a moist, generally cylindrical filter body and to advance the tow body in the feed direction of the mentioned arrow to the further components of the apparatus 1.

(13) Preferably the filter material is pushed inside the tubular element 8 along arrow 30 by means of a fluid jet, for example a pressurized air jet, generated by a pressurized fluid generator (not shown in the drawings).

(14) Tubular element 8 defines a through hole 20 through which the filter material can pass. Preferably, the through hole 20 comprises an inner surface 21 which compresses the filter material to form a substantially cylindrical rod-like shaped continuous strip of material. Further, preferably the tubular element 8 includes a steam generator 9 comprising one or more nozzles 11 which can emit steam in the interior of the tubular element 8, that is, in the through hole 20. The steam can harden the plasticizer present in the filter material and transform it into the substantially rigid filter rod or body.

(15) The apparatus 1 further comprises a drain channel 10 which is in fluid communication with the tubular element 8. The drain channel 10 is apt to drain fluid, such as water, which may condense inside the tubular element, so that the filter material flowing into the tubular element 8 does not get humid due to the fluid droplets. In the embodiment of FIG. 4, the drain channel 10 includes an aperture 12 in the inner surface 21 of the tubular element 8. The drain channel is opened and closed by means of a valve 40.

(16) Preferably, the apparatus 1 includes a central unit 100 is adapted to receive signals from the rod forming unit 4 and to command the opening and closing of valve 40. In the embodiment of FIGS. 5 and 6, the tubular element 8 is realized by a plurality of separated elements 16 disposed in series along the feeding direction of the filter material. The first of the separated element 16 in the direction of feed of the filter material is in fluid communication with a condensate chamber 15 which is connected to the portion of through hole 20 of the separated element 16. Preferably, one of the nozzles 11 to eject the steam is also realized in the first of the separated elements 16. In the chamber 15, the condensed fluid is collected. Then, the drain channel 10 departs from the chamber 15, for example from a bottom surface thereof, in order to drain the collected fluid. In this embodiment valve 40 is also present and has the same function as in the embodiment above described.