EP0654224A2 - Device for treating a strip of filter material - Google Patents

Abstract

The invention relates to a device for treating at least one strip of filter material for the tobacco-processing industry, which is extracted from a stock and which is fed to a stretching stage having a stretching means which is followed by an applicator stage with an applicator means for applying application fluid, etching the filter material, onto the strip, which applicator stage, in turn, is followed by a gathering stage having a gathering means reducing the width of the strip. The purpose of the invention is to achieve a further possibility for the treatment of filter material. In the solution according to the invention, the stretching stage, the applicator stage and the gathering stage form at least approximately the shape of a U or V. The advantage attainable by means of the invention is an improvement in the tow yield along with a constant pull resistance of the filter sticks produced from the treated material. Moreover, a reduction in the dimensions of a corresponding treatment apparatus is achieved. <IMAGE>

Description

The invention relates to an arrangement for processing at least one strip of filter material for the tobacco processing industry, which is taken from a supply and fed to a stretching section with a stretching device, which is followed by an application section with an application device for applying application liquid that dissolves the filter material onto the strip, which in turn a shirring section with a shirring device reducing the width of the strip is arranged downstream.

To produce filter rods for the tobacco processing industry, a strip of filter material, so-called filter tow, of interconnected fibers, e.g. B. from cellulose acetate, continuously from a supply, for. B. from a bale, peeled, spread, stretched, with a solvent, e.g. B. triazetine, sprayed, gathered laterally, a nozzle charged with blown air and then fed to a funnel, from which the prepared and compressed filter strip is fed to a filter rod machine. In the filter strand machine, the strip formed into a filter strand is continuously covered with a covering material strip with further compression, after which filter rods are cut off from the covered filter strand.
Proven processing devices of the type described above are manufactured and sold by the applicant under the designations AF 1, AF 2 and AF 3. Proven filter rod machines of the type described are built and sold by the applicant under the designations KDF 2 and KDF 3. The problem underlying the invention is to create a further advantageous processing arrangement for filter tow.

The solution according to the invention is that the stretching section, the application section and the gathering section form at least approximately the shape of a U or a V.

According to a preferred independent inventive development of the invention, the stretching section, which advantageously comprises at least two pairs of stretching rolls with different peripheral speeds, can have a length of 800 mm to 1200 mm, preferably 1000 mm. It has surprisingly been found that such a length gives optimal values with regard to the tow yield (tow amount per unit length with constant tensile resistance in the finished filter rod).
According to a further advantageous embodiment of the invention, the width of the filter strip in the stretching section and the application section can preferably be 120 mm to 150 mm. With such a small width, two or more filter tow strips simultaneously drawn off from bales and guided in parallel can be prepared relatively easily, for which purpose the same processing devices can predominantly be used. If the filter strand machine is then designed to process two filter tow strips simultaneously to encased filter strands (so-called two-strand machine), the production performance of a treatment plant can be increased significantly without major additional mechanical expenditure.

In an advantageous development of the invention, the stretching section can be arranged at least approximately vertically or with a predominantly vertical component with a preferred conveying of the strip from top to bottom. The Application device can be arranged in the preferably at least approximately horizontally arranged application section and can be designed as a spray device spraying the filter tow from both sides after releasing it from stretching with finely divided liquid such as triazetin to dissolve the filter tow fibers. According to a preferred embodiment of the invention, the gathering section can be arranged at least approximately vertically or with a predominantly vertical component with a preferred conveying direction of the filter tow strip from bottom to top. The gathering section and stretching section can have at least approximately the same length. If the stretching section as well as the application section and the gathering section are arranged in the form of a V, the stretching section can form one leg of the V, preferably with a strip conveyor running from top to bottom, while the application section and the immediately following gathering section, with the opposite conveying direction, form the other leg of the V form.

According to the invention, the actual stretching section can be preceded by a pre-stretching section, the conveying direction of the filter tow strip, which preferably runs from top to bottom, can have a vertical and a horizontal component. In the course of the stretching section, a conditioning device for conditioning the filter tow strip to a constant relative humidity, preferably a drying device, can be arranged in an advantageous, independent inventive rank of the invention. B. can be designed as an infrared heater.
The beginning of the stretching section can be a preferably non-drivable pair of rolls, the rolls of which can be pressed against one another with controllable force, while at the end of the stretching section the first pair of rolls of the actual stretching section can be arranged. The direction of the filter tow strip reversing roller pairs of stretching and application section can each z. B. existing metal roller with a grooved surface and a counter roller with an elastic surface. A pneumatic spreading nozzle can be arranged upstream of the stretching section, from which blown air emerges for spreading the filter tow fibers. According to a further embodiment of the invention, the application device can be provided with a charging device for applying electrostatic charges to the filter tow strip. This improves the separation of the fibers of the filter tow strip and makes spraying more uniform, especially when the droplets of the dissolving liquid receive charges with opposite polarity to the charges on the filter tow strip. The application device can advantageously be followed by a discharge device designed as an ionization device. According to the invention, the above-mentioned conditioning device, preferably in the form of a drying device, can be controlled by a control arrangement in order to achieve a constant relative humidity in the filter tow strip, to which a measurement signal can be fed from a moisture measurement device. The measuring device can be a device for detecting a field strength resulting from electrostatic charges on the filter tow strip. The electrostatic charge can e.g. B. generated by the stretching of the filter tow strip.

Significant advantages are associated with the invention. The tow yield can be increased considerably and a filter tow saving of several percent with the same tensile resistance of the filter rods produced with the processed filter tow can be achieved - The dimensions of the processing plant can be reduced; In addition, the "depth" of the system can be reduced to such an extent that several filter tow strips can be processed simultaneously.

The invention is explained in more detail using exemplary embodiments.

Figur 1

eine Aufbereitungsanordnung gemäß der Erfindung mit einer U-förmigen Anordnung von Reckstrecke, Auftragstrecke und Raffstrecke,

Figur 2

eine Variante der Aufbereitungsanordnung gemäß Figur 1 mit einer V-förmigen Anordnung von Reckstrecke , Auftragstrecke und Raffstrecke.

Show it:

Figure 1

a preparation arrangement according to the invention with a U-shaped arrangement of stretching section, application section and gathering section,

Figure 2

a variant of the processing arrangement according to Figure 1 with a V-shaped arrangement of stretching section, application section and gathering section.

According to FIG. 1, the processing arrangement for a strip 2 of filter tow, eg. B. cellulose acetate, with coherent fibers the following main assemblies:
A draw-off section 3 for a section 2a of the strip 2, a stretching section 4 for a section 2b of the strip 2, a stretching section 6 for a section 2c of the strip 2, an application section 7 for a section 2d of the strip 2, a gathering section 8 for a section 2e of the strip 2, a feed section 9 for feeding a section 2f to the inlet device 11 of a filter rod machine 12, shown schematically, e.g. B. of the type known in the tobacco processing industry KDF 2 or KDF 3 of the applicant.

The draw-off section 3, in which the filter material strip 2a is conveyed along the arrow 5, has one or more spreader nozzles 16 which receive compressed air from a compressed air source 17. The compressed air serves to spread the filter tow fabric conveyed in the direction of arrow 5 in section 2a. A - controllable - spreader nozzle is described in US-A-4,259,769.

The filter tow strip reaches the pre-stretch section 4 via deflection rollers 18, 19, which is delimited on the one hand by a pair of rollers 21 with the rollers 22, 23 and on the other hand by a pair of rollers 24 with motor-driven rollers 26, 27 - the rollers 22, 23 are separated by the tow strip 2b towed, ie they run empty with more or less resistance. If necessary, they can be driven by a motor. They can also be pressed against one another in a manner known per se with controllable force. The filter tow is pre-stretched in the pre-stretching section in which the strip section 2b is conveyed obliquely downwards in the direction of the arrow 28. It passes through a conditioning device 29 which is designed as a controllable drying device 31. In the drying device 31 provided with infrared radiators, the filter tow is conditioned in a controlled manner to a predetermined, preferably constant, relative humidity (water). A suitable drying device 31 is sold under the name WEKO-HEAT dryer by HAUG GmbH & Co. KG, PO Box 200333, D-70771 Leinfelden-Echterdingen. A speed sensor 32 known per se, which detects the speed of the filter strip 2b directly or indirectly, for example in a known manner via the speed of the motor-driven roller pair 24, outputs a signal dependent on the speed of the strip section 2b to an input a of a control arrangement 33, which controls an electrical energy source 34 for the drying device 31 by means of a signal at an output d such that the heating power increases when the speed of the strip section 2b increases, and decreases when the speed decreases. The signals supplied to the inputs b and c of the control arrangement 33 will be explained later.
Downstream of the drying device 31 is a charging rod 37 for applying electrostatic charges to the filter tow strip. The rod sold by the aforementioned company HAUG with the type designation ALS A 030-500 can be used with the charger 38 AG-3 neg / 7612 and AG-3 pos / 7609. The electrostatic charges of high potential applied to the strip section 2b ensure good separation of the individual fibers of the filter tow strip still adhering to one another by means of electrostatic repulsion forces, which is advantageous for the subsequent application of solvent droplets to the filter tow strip. Details of the application of electrostatic charges can be found in US-A-3 817 211 and the US defensive publication 665,476, U.S. Official Gazette 860/3 dated March 18, 1969.

The actual stretching section 6 adjoins the pair of rolls 24, in which section 2c of the filter tow strip is conveyed vertically or with a vertical component according to arrow 36 from top to bottom. At the end of the stretching section 6 there is a further pair of rollers 39 made of motor-driven rollers 41, 42, the peripheral speeds of which are somewhat greater than the peripheral speeds of the rollers 26, 27, so that the elastic filter tow is stretched in a defined manner in section 2c. The roller pairs 24 and 39 thus form the actual stretching device. Rollers 26 and 41 have a rigid grooved surface each touching a resilient surface of rollers 27 and 42, respectively. Such roller configurations are known from the aforementioned filter tow processing devices AF 1, AF 2 and AF 3 from the applicant and z. Described, for example, in US-A-3 317 965 and US-A-3 255 506.
In a particularly advantageous embodiment of the invention, which has independent inventive rank, the length c of the stretching section can be between 800 mm and 1200 mm, preferably about 1000 mm. It has been shown that, surprisingly, a particularly good tow yield can be achieved in this length range.

The pair of rollers 39 is followed by a further pair of rollers 43 made of motor-driven rollers 44, 46, the peripheral speeds of which are lower than those of the rollers 41, 42, so that the filter tow relaxes slightly in section 2d when it is conveyed in accordance with arrow 49. The pair of rollers 43 again has a roller 44 with a rigid grooved surface which is in contact with the resilient surface of the roller 46. Limit the pairs of rollers 39 and 43 thus the at least approximately horizontally arranged application section 7, in which an application device 47 in the form of a spraying device 48 is arranged. The spraying device 48 can be designed as described in US Pat. No. 4,313,974 and sprays the section 2d of the filter tow strip, which is transported in the direction of the arrow 49, from both sides with fine droplets of a solvent for the filter tow material, e.g. B. Triazetin. The width of the filter tow strip in the stretching section 6 and the application section 7 is preferably between 120 mm and 150 mm. This is such a small width that it allows processing devices for two filter tow strips guided in parallel to be arranged one behind the other perpendicular to the plane of the drawing and thus to be used twice. The strips can then be processed into filter rods in a filter strand machine that processes two strands simultaneously.

Downstream of the application section is the gathering section 8, in which section 2e of the filter tow strip is conveyed vertically or with a predominantly vertical component (as shown) by a pair of rolls 51 with motor-driven rolls 52, 53 from bottom to top in the direction of arrow 54. The roller 52 again has a rigid grooved surface, the contact roller 53 has a resilient surface. In the area of section 2e, gathering devices in the form of wire loops 56a ... 56c are arranged which constantly reduce the width of the filter tow in section 2e. For this purpose, the wire loops have different, ie, decreasing, dimensions.
In the gathering section 8 there is a moisture measuring device 57 in the form of a measuring device 58 for the field strength, which is caused by electrostatic charges which are located on the filter tow strip. This electrostatic Charges originate from stretching in stretching section 6. Additional charges, as described with the aid of the charging rod 37, are not expedient when the field strength is detected as the moisture measurement value of the filter material. The field strength is a measure of the content of water in the fibers of the filter tow. A corresponding output signal is fed to a comparison element 59 and compared there with a setpoint value output by a setpoint generator 61. The output signal of the comparator 59 acts on the input b of the control arrangement 33, the input c of which receives a signal from a temperature sensor 62 on the drying device 31. The signals fed to the inputs b and c, together with the signal fed to the input a, control the energy supply of the drying device 31 in such a way that the relative humidity of the filter tow is kept constant. This advantageous development of the invention also has an independent inventive rank.

Downstream of the pair of deflecting rollers 51 is the feed section 9, in which section 2f of the filter tow strip is conveyed in the direction of arrow 62 and is freed of adhering electrostatic charges which are disadvantageous for further processing by means of a discharge device 63. It is an ionizing device in the form of ring electrodes 64a, 64b, as it is sold by the aforementioned company HAUG under the type designation EI-RE 014-200 with the power pack 66 under the type designation EN-7/7703.
In the feed section 9 there is also a driven deflection roller 67 with a rounded groove 68 on the circumference rotating at the filter tow speed and a so-called stuffing nozzle 69, known per se, to which compressed air is supplied from an appealing compressed air source 71. 72 is an inlet funnel and 12 the filter rod machine.
The stretching section 6, application section 7 and gathering section 8 form at least approximately a U, the inclination of the gathering section in the direction of the stretching section being even greater than shown.

Mode of operation of the processing arrangement according to FIG. 1:

A filter tow strip 2 is pulled off the bale 1 and first spread out in section 2a.
In section 2b, the filter strip is first pre-stretched by the roller pairs 21 and 24, its relative humidity (water) being kept at a constant value by the drying device 31. In section 2c, the fibers of the filter tow strip are stretched by the rollers of the roller pairs 24 and 39 rotating at different peripheral speeds, with the roller pair 39 being the greater peripheral speed Has. In section 2d, the fibers of the filter tow strip are relaxed by the rollers of the roller pairs 39 and 43 rotating at different speeds because the roller pair 43 has a lower peripheral speed than the roller pair 39. e.g. B. Triazetin.
In section 2e, the filter tow strip, which is conveyed by the roller pairs 51 and 43, is gathered by the wire loops 56a ... 56c, the width of which decreases in each case, ie the width perpendicular to the plane of the drawing is reduced. At the same time, the moisture is detected by the measuring device 58 and a corresponding measuring signal is sent to the control arrangement 33 for the drying device 31.
In section 2f the filter material is passed through the ionizer 64a, 64b freed of its electrostatic charges and, after deflection on the roller 68, fed to the funnel 72 and the inlet 11 of the filter rod machine 12 via the stuffing nozzle 69.

In the variant according to FIG. 2, the stretching section 6 forms one leg of a V, while the application section 7 and the gathering section 8 form the other leg. As in FIG. 1, the stretching section 6 is formed by the two motor-driven roller pairs 24 and 39. Their length c is also preferably between 800 mm and 1200 mm, advantageously 1000 mm.
The application device 47 has a spraying device 48 which contains rapidly rotating rotors 50 which spray the supplied solution liquid in the form of thin spray threads 55 onto the filter tow 2d. Such application devices are sold by Weitmann & Konrad GmbH & Co. KG, Postfach 200252, D-70771 Leinfelden-Echterdingen, under the name WEKO-ROTORENBEFEUCHTUNG für MATERIALBAHNEN. For reasons of space, only spraying from one side is shown. However, spraying from both sides is also possible with the aforementioned spraying devices.
The shirring section 8 directly adjoins the application section 7 with its wire loops 56a ... 56c, which ends at the pair of rollers 51.
The plant sections upstream of the stretching section 6 and those downstream of the application section 7 and the gathering section 8 can be designed as described in FIG. 1.

Claims (23)

Arrangement for processing at least one strip (2) of filter material for the tobacco processing industry, which is taken from a supply (1) and fed to a stretching section with a stretching device (24, 39), which has an application section (7) with an application device (48) for Applying application liquid which dissolves the filter material is arranged downstream of the strip (2d), which in turn is followed by a gathering section (8) with a gathering device (56a ... 56c) which reduces the width of the section (2e), characterized in that the stretching section, the application section and the gathering section form at least approximately the shape of a U or a V. Arrangement according to claim 1, characterized in that the length of the stretching section (6) with the stretching device (24, 39), which preferably comprises at least two pairs of rollers driven at different speeds, is between 800 mm and 1200 mm, preferably approximately 1000 mm. Arrangement according to claim 2, characterized in that the width of the strip (2c, 2d) in the stretching section (6) and application section (7) is between 120 to 150 mm. Arrangement according to one or more of the preceding claims, characterized in that the stretching section (6) is arranged at least approximately vertically or with a predominantly vertical component with a preferred conveying direction (36) of the strip (2c) from top to bottom. Arrangement according to one or more of the preceding claims, characterized in that with a V-shape of Stretching section (6) and application section (7) and shirring section (8) the stretching section with the conveying direction (36) directed from top to bottom forms one leg of the V, while the application section and the immediately adjacent shirring section with the conveying direction directed from bottom to top (47, 54) forms the other leg. Arrangement according to one or more of the claims according to one or more of the preceding claims, characterized in that the application device (47) in the application section (7) is designed as a spray device (48) which applies the application liquid in the form of finely divided droplets from both sides. Arrangement according to claim 6, characterized by a guidance of the strip (2d) in the area of the application section (7), in which the tension of the strip is reduced compared to the stretching section (6). Arrangement according to one or more of the preceding claims, characterized in that the gathering section (8) is arranged at least approximately vertically or with a predominantly vertical component with a preferred conveying direction (54) of the strip (2e) from bottom to top. Arrangement according to one or more of the preceding claims, characterized in that the stretching section (6) and the gathering section (7) have at least approximately the same lengths. Arrangement according to one or more of the preceding claims, characterized in that the stretching section (6) is preceded by a pre-stretching section (4). Arrangement according to Claim 10, characterized in that the strip (6b) has a conveying direction (28), preferably directed from top to bottom, in the stretching section (4) with a horizontal and a vertical conveying component. Arrangement according to claim 10 and / or 11, characterized in that a conditioning device (29) for conditioning the strip (2b) to at least approximately constant relative humidity is arranged in the course of the stretching section (4). Arrangement according to claim 12, characterized in that the conditioning device has a controllable drying device (31). Arrangement according to claim 13, characterized in that the drying device (31) has an infrared heater for drying the strip (2b). Arrangement according to one or more of the preceding claims, characterized in that the pre-stretching section (4) is provided by an upstream pair of rolls (21) and a further driven pair of rolls (24) which, seen in the conveying direction of the strip (2b), the first pair of rolls of the stretching section (6) is formed. Arrangement according to claim 15, characterized in that the upstream pair of rollers (21) is not driven. Arrangement according to one or more of the preceding claims, characterized in that at least one spreading nozzle (16) is arranged downstream of the supply (1) the air that spreads the strip (2a). Arrangement according to one or more of the preceding claims, characterized in that the roller pairs (24, 39, 43, 51) of stretching section (6), application section (7) and gathering section (8) each consist of a roll with a smooth elastic surface and a roll with a rigid grooved surface. Arrangement according to one or more of the preceding claims, characterized in that the application device (47) is preceded by a charging device (37) for applying electrostatic charges to the strip (2b). Arrangement according to claim 19, characterized in that the application section (7) is followed by a discharge device (64a, 64b) for removing the electrostatic charges on the strip (2f). Arrangement according to one or more of the preceding claims, characterized in that a moisture measuring device (57) is provided in the region of the conveyor path of the strip (2e), the output signal of which depends on the moisture of the strip being fed to a control arrangement (33) for the conditioning device (29) is. Arrangement according to claim 21, characterized in that the moisture measuring device (57) is a measuring device (58) for the size of a field strength resulting from electrostatic charge on the strip. Arrangement according to one or more of the preceding Claims, characterized by at least one removal device for the simultaneous removal of two or more strips of filter material from the supply and by processing devices for the simultaneous processing of two or more strips.

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