DE102015108968A1 - Method, applicator and machine for producing a filter strand of the tobacco processing industry - Google Patents

Abstract

The invention relates to a method for producing a filter strand of the tobacco-processing industry, in which a filter material strip (12) of the tobacco processing industry spread, sprayed in the expanded state with a liquid additive (20) by at least one application nozzle (22) and then to a filter strand wherein additive (20) is pumped from an additive reservoir (38) through an inlet (30) to the at least one application nozzle (22), and sprayed additive (20) that is not received by the filter material strip (12) through a return (34) to the additive reservoir (38) is returned, and a corresponding applicator (10, 100, 102) and a machine of the tobacco processing industry. According to the invention, an inlet volume flow (v. Inlet) of the admixture (20) in the inlet (30) and a return volume flow (v. Return) of the admixture (20) in the return (34) are determined and a differential volume flow (v Diff) of the admixture (20) is determined as the difference between inlet volume flow (ν inlet) and return flow volume (ν return), which is used as a control variable of a volume flow control (50) of the additive application and a predetermined or predeterminable Target volumetric flow (ν.

Description

The invention relates to a method for producing a filter strand of the tobacco processing industry, in which a strip of filter material spread the tobacco industry, sprayed in the expanded state with a liquid additive through at least one applicator nozzle and then formed into a filter strand, said additive from an additive reservoir in an inlet to the at least one application nozzle is pumped and sprayed additive, which is not absorbed by the strip of filter material, is returned by a return to the additive reservoir, and a corresponding applicator and a machine of the tobacco processing industry.

In the production of filter strands for the tobacco processing industry, a strip of filter material, usually a filter tow, which is usually made of cellulose acetate, withdrawn as a quasi-endless strip from a supply and treated. The filter tow consists of a web of loosely adhering threads that are pulled apart to form a broad and flat web. This propagation takes place by means of a spreader nozzle. After stretching and spreading, the web is fed an additive which is mostly liquid and consists, for example, of a plasticizer, such as triacetin, in finely divided form. The softener droplets dissolve the filaments so that when they are combined into a round filter strand and wrapped with a filter paper strip, they permanently adhere to one another in a filter rod machine.

In the application of additive to the strip of filter material, the uniformity of the order is of great importance, since the amount of applied additive affects the filtration properties of the filters thus produced. Therefore, it must be ensured that the amount of plasticizer or additive contained in each filter remains constant over the time of production or within predetermined tolerances.

Out DE 199 59 034 A1 It is known to spray filter tow with a transverse to the direction of movement of the filter tow row of nozzles with an additive or a plasticizer. Here, the individual nozzles are controlled by upstream, the density of the filter tow in the sections concerned sensors.

When using application nozzles, a constant pressure in the supply line to the application nozzle is alternatively used, so that the desired fine distribution of the droplets of the additive remains ensured. In order to be able to control the amount of additive introduced into the strip of filter material, is in DE 10 2005 015 877 A1 For example, discloses a device in which by a constant delivery pressure of the additive or plasticizer by means of spray nozzles uniform application of the plasticizer is achieved on the applied filter tow. Plasticizer not absorbed by the filter tow is collected in a catch basin or drip pan. It is also a cover plate disclosed by means of which the application surface can be increased or reduced by moving the cover plate.

In order to check that the amount of additive in the individual filters remains constant over the production time, individual filters are usually taken randomly and weighed, whereby several hours can pass between the samples. In EP 1 935 261 B1 a closer control is proposed by filling a calibrated container with a well-defined quantity of additive, removing it from the additive and applying it to filter material strips by means of a rotating brush which receives additive and sprays finely divided by rapid rotation. Unaccumulated additive is returned to the container. Electronic sensors give signals when the level falls below an upper level and falls below a lower level. After falling below the upper level level, a count of the produced filter is started and stopped after falling below the lower level level, so that it is known exactly how many filters the known volume of additive has been used. From this, the average amount of additive per filter produced is determined for this measurement. After falling below the lower filling level, the volume is replenished and another measurement is started, so that there is a cyclical monitoring of the amount of additive in the filters produced.

In contrast, the present invention has the object to further improve the monitoring of the entry of additive in the filter material strip.

This object is achieved by a process for producing a filter rod of the tobacco processing industry, in which a strip of filter material of the tobacco processing industry spread, sprayed in the expanded state with a liquid additive through at least one application nozzle and then formed into a filter strand, wherein additives from an additive reservoir is pumped through an inlet to the at least one application nozzle and sprayed additive, which is not absorbed by the strip of filter material, by a return to Is returned additive reservoir, solved, which is further developed in that an inlet volume flow ν. _Intake of the additive in the inlet and a return flow ν. _returns of the additive are determined in the return and a differential flow ν. _Diff of the additive as the difference between inlet volume flow ν. _Intake and return flow ν. _returns is determined, which is used as a controlled variable of a volume flow control of the additive application and to a predetermined or predeterminable desired volume flow ν. _Should is regulated.

The invention is based on the recognition that the transition from the introduced amount of additive, for example plasticizer, in particular triacetin, to a volume flow of the introduced additive allows a qualitative leap from a cyclic monitoring to a continuous monitoring. To capture the amount of additive introduced had always been integrated over a certain amount of additives, so that only an average entry per filter over a certain measurement period was detected. On the other hand, the volume flow is detected instantaneously or continuously, so that an individual measurement result can be assigned to each individual filtered filter rod. As in the prior art, the additive is used in a cycle by being conveyed from the additive reservoir through the inlet to the applicator nozzle, and additives that have not been taken up by the filter material strip are collected and returned by a return to the additive reservoir. The additive taken up and removed by the filter material strip forms a volumetric flow which, in the case of equilibrium, represents the difference between the inlet volumetric flow and the return volumetric flow.

For volumetric flow control, a setpoint volumetric flow is used as the setpoint for the controlled variable, namely the differential volumetric flow. Absolute values of the filling level in the collecting container or in the additive reservoir or intermediately stored containers are of no importance in the first place.

An advantageous further development provides that in addition a level control in a arranged before or in return level container with the control target of a vanishing time derivative ḣ _Soll = 0 of the time course of a level in the level tank takes place, with a control of the inlet flow rate ν. _Intake and / or the return flow rate ν. _returns he follows. For this second regulation, it is also not on the absolute value of the level in the level tank on, but only on the change in level height with time, which should disappear. So it depends on the constancy of the filling level, not on the actual value of the filling level. Characterized in that the level in the level tank is constant, it is ensured that the differential volume flow, which is the control variable of the volume flow control, exactly corresponds to the volume flow of the removed with the filter material strip additive.

Even in the case that the level changes, can be from the change in the level height, ie the first time derivative of the level height, a correction for the controlled variable differential flow ν. _Diff Determine the flow control and thus adapt the scheme to this.

For controlling the return flow rate ν. _returns is preferably a proportional valve in the return or a pump speed of a return pump in the return adjusted. This has the advantage that the inlet can be operated at a constant pumping speed or at a constant pumping pressure in order to ensure the most uniform atomization or atomization of the additive in the at least one application nozzle. Therefore, for the level control, the control of the volume flow in the return is more appropriate than that in the inlet. In other cases, where a good atomization is ensured even with different inlet flow rates, and the inlet flow rate can be controlled for this purpose. This is usually the case within certain tolerance ranges.

In an advantageous development, a control of a quantity of additive introduced into the strip of filter material takes place by means of a sheet, which is at least partially insertable into a spray cone produced by the at least one application nozzle. With a reduction of the application surface by inserting the sheet into the spray cone of the at least one application nozzle, the amount of additive, which is not absorbed and thus must be recycled, increased. The return flow increases accordingly, or the level in the level tank increases. When pulling out the sheet, it is the other way around. Accordingly, the control of the return flow rate through the level height control, possibly also the control of the inlet flow rate, to adapt to reach the control target of the constant level height.

In two advantageous alternatives, which can also be used alternately, depending on the machine operation, it is provided that the volume flow control at least in temporal sections dynamic machine behavior continuously and / or at least in temporal sections constant machine behavior is operated time-discrete. Dynamic machine behavior means, for example, starting and stopping the machine. In these time periods, the engine speed changes very much, as does the engine temperature. Therefore, the order conditions for the additive change quite quickly, so that a continuous control of the flow rate is advantageous. Especially in these times of dynamic machine behavior, the regulation according to the invention via volume flows is clearly superior to the regulation of volumes because of their speed. In time sections of constant machine behavior, ie approximately constant machine speed and other conditions, the control effort can be reduced by the volume flow control is operated time-discrete.

Advantageously, a machine speed and the difference volume flow ν. _Diff and optionally a predetermined filter rod length an amount of additive per filter or per filter length or length unit calculated in the filter strand. The unit of length is, for example, cm of the filter strand.

Further preferably, insufficiently sprayed filters which had been sprayed at a point in time at which the differential volume flow was discharged are discharged ν. _Diff beyond a predetermined or predeterminable tolerance value from the desired volume flow ν. _Should has deviated or the calculated amount of additive per filter or per filter length or unit length in the filter strand over a predetermined or predeterminable tolerance value deviates from a desired amount.

The volume flow control is advantageously adapted so that the desired volume flow of the additive is proportional to the machine speed. This ensures that the amount of added in the filter material strip additive is independent of the machine speed.

The object of the invention is also based on an applicator for applying a liquid additive to a spreading filter material strip of the tobacco industry, comprising at least one application nozzle, a Zusatzmittelvorratsbehälter, an inlet and an inlet pump, by means of the additive from the additive reservoir through the inlet to at least one Order nozzle is pumped or pumped, and a return, by means of which not included in the filter material strip additive is traceable into the additive reservoir, solved, which is further developed by an inlet-measuring device for measuring an inlet flow rate ν. _Intake the additive in the inlet and a return measuring device for measuring a return flow rate ν. _returns the additive in the return are included as well as a volume flow control device which is formed a differential volume flow ν. _Diff of the additive as the difference between inlet volume flow ν. _Intake and return flow ν. _returns to be determined and used as a control variable for a volume flow control of the additive application and to a predetermined or predeterminable desired volume flow ν. _Should to regulate.

By means of the applicator according to the invention, the features, advantages and properties of the method according to the invention described above are realized in the same way. The volumetric flow control device is preferably a controller with continuous behavior, for example a P, PI, PD or PID controller. The controller can be analog or digital.

In addition, a fill level container arranged in front of or in the return, which is designed in particular as a collecting trough, and a fill height control device which is designed to additionally control the feed volume flow ν. _Intake and / or the return flow rate ν. _returns with a control target of a vanishing time derivative (ḣ _set = 0) to control a time course of a level height in the level tank. The filling height control device is a corresponding preferably continuous and linear regulator.

In an advantageous development, a controllable proportional valve and / or a controllable return pump is or are arranged in the return.

Also advantageously, a sheet is included, which is at least partially inserted into a spray cone generated by the at least one application nozzle to control an amount of registered in the filter material strip additive.

The inlet measuring device and / or the return measuring device is or are advantageously designed as a volume flow measuring device or as a speed measuring device for a pump.

The applicator is preferably designed and configured to carry out a method according to the invention described above.

The object underlying the invention is finally by a machine of the tobacco-processing industry with a previously solved inventive applicator described.

The machine also has the same features, advantages and properties due to the applicator according to the invention contained therein, as the subject invention described above.

Preferably, a discharge device is provided for discharging filter rods cut to length from the filter rod, by means of which filter rods can be removed which are insufficiently sprayed.

Further features of the invention will become apparent from the description of embodiments according to the invention together with the claims and the accompanying drawings. Embodiments of the invention may satisfy individual features or a combination of several features.

The invention will be described below without limiting the general inventive idea by means of embodiments with reference to the drawings, reference being expressly made to the drawings with respect to all in the text unspecified details of the invention. Show it:

1 a schematic representation of an applicator according to the invention,

2 a further embodiment of an applicator according to the invention and

3 a further example of an applicator according to the invention in a schematic representation.

In the drawings, the same or similar elements and / or parts are provided with the same reference numerals, so that apart from a new idea each.

1 shows an applicator according to the invention 10 in a schematic representation, wherein the control devices are omitted for reasons of clarity. It is a section of a machine, not shown, of the tobacco-processing industry, in which an already spread filter material strip 12 by means of two pairs of rollers 16 . 18 in a conveying direction 14 is encouraged. Between the roller pairs 16 and 18 becomes the filter material strip 12 , for example, a cellulose acetate tow, via an applicator nozzle 22 carried away, which also has a series of juxtaposed applicator nozzles 22 that can be a spray cone 21 from a liquid additive formed into a spray 20 towards the filter material strip 12 , so upwards, gives up. The additive may, for example, be a plasticizer, for example triacetin. With the reference number 24 is a volume flow of the additive 20 referred to, with the filter material strip 12 from the applicator 10 is removed. This removed additive volume flow 24 is ideally sized so that per unit length of the filter material strip 12 the same amount of additives 20 is available.

The application nozzle 22 is in an upwardly substantially closed container with a drip pan 26 arranged in the additive 20 not from the filter material strip 12 is recorded, is caught. This results in a level 28 in the tub 26 ,

At the bottom of the 1 is an additive reservoir 38 shown a supply of additives 20 has and with two lines, namely an inlet 30 and a return 34 , connected in the form of dip tubes in the additive 20 in the additive reservoir 38 are immersed.

The feed 30 is with an inlet measuring device 32 and a means not shown for pumping additive 20 from the additive reservoir 38 to the application nozzle 22 Mistake. The return 34 is with a return flow measuring device 36 Mistake. In the inlet measuring device 32 it may also be a measuring device which determines, for example, the rotational speed of the pump, not shown. In this way is also the inlet flow rate of additives 20 determined.

In the 1 illustrated applicator 10 thus already provides all the information that is necessary for a volume flow control according to the invention.

Concrete embodiments of the scheme are in the 2 and 3 shown schematically in more detail.

2 shows an applicator according to the invention 100 In many details similar to the applicator 10 out 1 is constructed. In addition, the applicator includes 100 out 2 another slidable sheet metal 60 , with which the application surface can be reduced by the fact that the sheet metal 60 in the spray cone 21 is pushed in and thus covers part of the spray cone before this part of the additive 20 the filter tow or the filter material strip 12 can reach.

At the bottom of the 2 is a volume flow control 50 shown, which is a flow control device 52 that includes in her Input receives a prepared input signal. This is generated as follows. The inlet measuring device 32 and the return measuring device 36 each give a signal that a measured inlet flow rate ν. _Intake or a return flow ν. _returns equivalent. These signals are transmitted over data lines 51 . 53 , which can also be signal lines, a difference images 54 supplied, which from the two volume flows a differential volume flow ν. _Diff forms. This difference signal is transmitted via another data line 55 another difference pictures 56 fed, this difference signal ν. _Diff from a volume flow setpoint signal ν. _Should withdraws. The result of the regulation is via a control line 58 to an unillustrated control device for the displaceable sheet metal 60 forwarded, which is moved accordingly, so that the application surface of the additive 20 on the filter material strip 12 enlarged or reduced.

A second control loop is in the form of a filling height control 70 in the right part of the 2 shown. A signal about the level 28 in the drip tray 26 , which in this case as a level container 71 is differentiated over time and over a data line 78 to a difference picture 74 , which subtracts this time-derived signal from a signal related to the target level-height change ḣ _target , which is set to 0. A level control device 72 the filling level control 70 uses this signal to over a control line 76 a proportional valve 80 in the return 34 to open or narrow when the level 28 is not constant. Alternatively, the signal for the level 28 also in the difference pictures 74 be compared with a time-delayed signal to produce in this way the time derivative of the level.

3 shows a further embodiment of an applicator according to the invention 102 that differ from the applicator 100 different in several points. So are in this embodiment both in the flow 30 as well as in the return 34 instead of volumetric flow measuring devices in each case pumps, namely an inlet pump 33 and a return pump 37 provided, the pumping speed in each case as a measure of the volume flow of the additive 20 in the inflow 30 and in the return 34 serves. In the return 34 is also an independent level tank 71 below the collection cheek 26 arranged, which allows a very accurate determination of level heights and level height changes due to a constriction. Also unlike 2 is in 3 for filling level control by means of the filling height control device 72 directly the pumping speed of the return pump 37 driven. The remaining details of the applicator 102 correspond to those of the previously described applicator 100 out 2

All mentioned features, including the drawings alone to be taken as well as individual features that are disclosed in combination with other features are considered alone and in combination as essential to the invention. Embodiments of the invention may be accomplished by individual features or a combination of several features. In the context of the invention, features which are identified by "particular" or "preferably" are to be understood as optional features.

LIST OF REFERENCE NUMBERS

10

applicator

12

Filter material strips

14

conveying direction

16, 18

roller pair

20

liquid additive

21

spray cones

22

application nozzle

24

removed additive volume flow

26

drip tray

28

level

30

Intake

32

Feed-measuring device

33

feed pump

34

returns

36

Return-measuring device

37

Return pump

38

Additive reservoir

50

Volume Flow Control

52

Flow control device

51, 53

data line

54, 56

difference images

58

control line

60

sliding sheet metal

70

Filling height control

71

level container

72

Füllhöhenregelvorrichtung

74

difference images

76

control line

78

data line

80

proportional valve

100

applicator

102

applicator

ν. _Intake

Intake volume flow

ν. _returns

Return flow

ν. _Diff

Differential flow rate (ν _inflow - ν _{return flow} )

ν. _Should

Set volume flow

ḣ _Soll

Target level altitude change

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 19959034 A1 [0004]
• DE 102005015877 A1 [0005]
• EP 1935261 B1 [0006]

Claims (15)

Method for producing a filter rod of the tobacco-processing industry, in which a filter material strip ( 12 ) of the tobacco-processing industry, in the expanded state with a liquid additive ( 20 ) by at least one applicator nozzle ( 22 ) is sprayed and then formed into a filter strand, wherein additives ( 20 ) from an additive reservoir ( 38 ) by an inlet ( 30 ) to the at least one applicator nozzle ( 22 ) and sprayed additive ( 20 ) that is not from the filter material strip ( 12 ), by a return ( 34 ) to the additive reservoir ( 38 ), characterized in that a feed volume flow ( ν. _Intake ) of the additive ( 20 ) in the inflow ( 30 ) and a return volume flow ( ν. _returns ) of the additive ( 20 ) in the return ( 34 ) and a differential flow rate ( ν. _Diff ) of the additive ( 20 ) as difference between inflow volume flow ( ν. _Intake ) and return flow ( ν. _returns ), which is the controlled variable of a volumetric flow control ( 50 ) of the additive application is used and to a predetermined or predeterminable desired volume flow ( ν. _Should ) is regulated. A method according to claim 1, characterized in that in addition a level height control ( 70 ) in one before or in the return ( 34 ) arranged level container ( 71 ) with the control objective of a vanishing time derivation (ḣ _setpoint = 0) of the time course of a filling level height in the filling level container ( 71 ), wherein a control of the inlet volume flow ( ν. _Intake ) and / or the return flow rate ( ν. _returns ) he follows. A method according to claim 2, characterized in that for controlling the return flow rate ( ν. _returns ) a proportional valve ( 80 ) in the return ( 34 ) or a pumping speed of a return pump ( 37 ) in the return ( 34 ) is adjusted. Method according to one of claims 1 to 3, characterized in that a control of an amount of in the filter material strip ( 12 ) registered additive ( 20 ) by means of a sheet ( 60 ), which is in one of the at least one application nozzle ( 22 ) spray cone ( 21 ) is at least partially insertable. Method according to one of claims 1 to 4, characterized in that the volume flow control ( 50 ) is operated time-discretely, at least in temporal sections of dynamic machine behavior, continuously and / or at least in time sections of constant machine behavior. Method according to one of claims 1 to 5, characterized in that from a machine speed and the differential flow rate ( ν. _Diff ) and optionally a predetermined filter rod length an amount of additive ( 20 ) per filter or per filter length or unit of length in the filter strand. Method according to one of claims 1 to 6, characterized in that insufficiently sprayed filters are discharged, which were sprayed at a time at which the differential flow rate ( ν. _Diff ) beyond a predetermined or predeterminable tolerance value from the desired volume flow ( ν. _Should ) or the calculated amount of additive ( 20 ) per filter or per filter length or unit of length in the filter train over a predetermined or predeterminable tolerance value deviates from a desired amount. Applicator ( 10 . 100 . 102 ) for applying a liquid additive ( 20 ) on a spread filter material strip ( 12 ) of the tobacco processing industry comprising at least one applicator nozzle ( 22 ), an additive reservoir ( 38 ), a feed ( 30 ) and a feed pump ( 33 ), by means of the additive ( 20 ) from the additive reservoir ( 38 ) through the inlet ( 30 ) to at least one applicator nozzle ( 22 ) is pumpable or pumped, and a return ( 34 ), by means of which not in the filter material strip ( 12 ) ( 20 ) into the additive reservoir ( 38 ) is traceable, characterized in that an inlet measuring device ( 32 ) for measuring a feed volume flow ( ν. _Intake ) of the additive ( 20 ) in the inflow ( 30 ) and a return measuring device ( 36 ) for measuring a return flow rate ( ν. _returns ) of the additive ( 20 ) in the return ( 34 ) and a volume flow control device ( 52 ), which is designed to generate a differential volume flow ( ν. _Diff ) of the additive ( 20 ) as difference between inflow volume flow ( ν. _Intake ) and return flow ( ν. _returns ) and as a controlled variable for a volume flow control ( 50 ) of the additive application and to a predetermined or predeterminable nominal volume flow ( ν. _Should ). Applicator ( 10 . 100 . 102 ) according to claim 8, characterized in that additionally in front of or in the return ( 34 ) arranged level container ( 71 ), in particular as a collecting trough ( 26 ), and a filling height control device ( 72 ), which is designed to control the feed volume flow ( ν. _Intake ) and / or the return flow ( ν. _returns ) with a control target of a vanishing time derivative (ḣ _target = 0) of a time course of a level height in the level container ( 71 ) to control. Applicator ( 10 . 100 . 102 ) according to claim 8 or 9, characterized in that in the return ( 34 ) a controllable proportional valve ( 80 ) and / or a controllable return pump ( 37 ) is or are arranged. Applicator ( 10 . 100 . 102 ) according to one of claims 8 to 10, characterized in that a sheet ( 60 ) which is in one of the at least one application nozzle ( 22 ) spray cone ( 21 ) is at least partially insertable to a quantity of in the filter material strip ( 12 ) registered additive ( 20 ) to control. Applicator ( 10 . 100 . 102 ) according to one of claims 8 to 11, characterized in that the inlet measuring device ( 32 ) and / or the return measuring device ( 36 ) as a volume flow measuring device or as a speed measuring device for a pump ( 33 . 37 ) is or are formed. Applicator ( 10 . 100 . 102 ) according to one of claims 8 to 12, characterized in that it is designed and arranged to perform a method according to one of claims 1 to 7. Machine of the tobacco processing industry with an applicator ( 10 . 100 . 102 ) according to any one of claims 8 to 13. Machine according to claim 14, characterized in that a discharge device for discharging filter rods cut to length from the filter rod is included, by means of the filter rods are ausschleusbar, which are insufficiently sprayed.

Images