EP0887462A2 - Machine to manufacture a material web - Google Patents

Abstract

This drying machine manufactures a paper or card web. It novel design is intended for smooth, uninterrupted start-up. It has two rows of heated drying cylinders, one above the other. Each row includes a conveyor belt, meandering between the cylinders and return rollers associated with that row. The web passes around upper and lower drying cylinders in alternation, being unsupported between them. Nozzles (37) jet air against the direction of the web, assisting lacing of the drying machine. A new feature is the additional guidance unit (47, 49) on the opposite side of the web to the first nozzle unit. The gas stream (51) it produces, runs with the web.

Description

The invention relates to a machine for manufacturing a material web, especially paper or Cardboard web, according to the preamble of claim 1.

Machines of the type mentioned here are known (EP 0 479 748 B1). They include a dryer section, which has a two-tier dryer group. The Drying group includes several, on top and one a lower row of drying cylinders, around the one material web, together with one Conveyor belt is guided. In the area between the The material web becomes a drying cylinder row in one led free train, that is, the material web is not supported by a conveyor belt. A known machine also includes one of the flyover a threading strip, also known as a ribbon serving nozzle device, the Gas flow against the direction of travel of the material web passed.

In the event of a web break or when the machine is started up for the production of the material web first the threading strip from the one Press section exiting material web cut off and threaded it through the dryer section. This is generally done at full speed the web production machine. Leadership and stabilization are therefore required of the threading strip so that this on the one hand not wrapped around one of the drying cylinders and on the other hand, safely in the transfer area between the upper and lower row of drying cylinders can be transferred. To do this a nozzle device in the known machine used in the area of the opening nip a drying cylinder, that is, arranged in the outlet area and is the web of material from the drying cylinder decreases, so that this at the -in the direction seen the material web- following Drying cylinders of the other row are transferred can. It turned out to be disadvantageous that the transfer of the threading strip is not in in all cases safely, so that a threading process frequently canceled and cleaning the Drying section must be carried out, resulting in a Machine can come to a standstill.

It is therefore an object of the invention to provide a machine to create a safe threading of the material web or the threading strip can be guaranteed.

To solve this task, a machine is proposed the features mentioned in claim 1 having. This is indicated by an that opposite the first nozzle device Guide device arranged on the material web side, which comprises at least one second nozzle device, whose gas flow essentially in the direction of Material web runs. The opposite of the running direction the material flow directed gas stream the first Nozzle device prevents the material web sticks to a drying cylinder and is wound on this. The leadership facility guides and stabilizes the threading strip, being by in the direction of the web of material directed gas flow of the second nozzle device the threading strip is worn and therefore securely on those following in the direction of travel of the material web Drying cylinder of the other drying cylinder series can be transferred. Through the exclusively directed in the direction of travel of the material web Gas flow of the second nozzle device can continue to twist the threading strip can be prevented safely.

An embodiment of the machine is preferred, which is characterized in that the first Nozzle device is attached to a scraper, and that the surface facing the material web of the scraper and that facing the material web Surface of the guide device essentially run parallel to each other. The scraper and the Management facility limit an even Gap through which the web of material passes becomes. The material web is therefore on both sides performed so that this in the desired manner on the subsequent drying cylinders are placed can.

Furthermore, an embodiment of the machine preferred, in which a cutting device is provided is for tearing off a threading strip from the web of material. It is provided that the cutting device on at least one essentially across the width of the material web extending crossbar is arranged. The functional reliability the cutting device can in particular can be increased in that the traverse -in Direction of travel of the material web seen - aligned is arranged behind the scraper. This covers the Traverse in such a way that a deposit of material web scraps that when transferring the material web fall off from this, can be safely prevented. It also ensures that the cutting device concealed behind the traverse when threading is arranged so that it is a threading process not prevented. By arranging the Cutting device immediately behind the scraper can finally be a particularly compact design of the machine.

Further embodiments result from the others Subclaims.

Figur 1

einen Teil einer Trockenpartie in schematischer Seitenansicht;

Figur 2

einen Ausschnitt aus einem weiteren Ausführungsbeispiel der Trockenpartie und

Figur 3

eine schematische Seitenansicht eines Teils eines dritten Ausführungsbeispiels der Trockenpartie.

The invention is explained below with reference to the drawing. Show it:

Figure 1

part of a dryer section in a schematic side view;

Figure 2

a section of a further embodiment of the dryer section and

Figure 3

is a schematic side view of part of a third embodiment of the dryer section.

The machine described below is general can be used for the production of material webs. By way of example only, it is assumed that it is a machine for producing a Paper web, i.e. around a paper manufacturing machine, acts.

Figure 1 shows schematically a section of a Dryer section 1 of the paper making machine, namely part of a two-tier dryer group 3, which has several drying cylinders, one of which here only the drying cylinders 5 to 15 are shown are. The axes of rotation of the drying cylinders 5, 7, 9 lie in an imaginary first level E1 and that of the drying cylinder 11, 13, 15 in an imaginary second level E2. The dotted lines Levels E1 and E2 run parallel at a distance to each other. The drying cylinders 5, 7, 9 of the top row is also called a dryer or -felt designated conveyor belt 17 assigned to the the drying cylinders 5, 7, 9 of the top row and these associated deflection rollers 19, 21, 23 meandering circulates. Another conveyor belt 25 rotates the drying cylinders 11, 13, 15 of the lower ones Row and associated guide rollers, of which in Figure 1 only the deflection rollers 27 and 29 are shown meandering.

One generally referred to below as material web 31 Paper web passes through dryer group 3 from left to right (see arrow 33) and will alternately around a drying cylinder of the lower one Row and around a drying cylinder of the top Row led. In the area between the rows of drying cylinders the material web 31 in one free train led, that is the material web is supported by neither of the two conveyor belts. The Drying cylinders of drying group 3 is in each case a scraper 35 assigned in the discharge area of the Drying cylinder is arranged, that is in the area in which the material web 31 from the drying cylinder expires. The scrapers 35 are identical trained so that in the following only the drying cylinder 11 assigned scraper 35 described becomes. The scraper 35 lies on the surface of the Drying cylinder 11 and prevents a web break committee around the drying cylinder 11 wraps. It also serves as one Ribbon designated threading strip, the edge area the web of material 31 when the papermaking machine starts up from the material web 31 is separated, to the drying cylinder 5 of the upper Convict row. The scraper 35 runs So - depending on its function - over the entire Width of the drying cylinder 11 or only a partial area, who is preferably on the leader's side Machine lies. There are two on the scraper 35 here Nozzle devices 37 and 39 attached. The first Nozzle device 37 comprises a blow pipe from which a gas flow 41 emerges that is essentially counter the running direction of the material web 31 directed is. The nozzle device 39 also has a blowpipe from which a substantially in Direction of the material web 31 directed gas flow 43 exits.

On the opposite side of the web with the drying cylinders 11, 13, 15 of the lower ones Row interacting scraper 35 is one Guide device 45 arranged. This includes in this embodiment two nozzle devices 47 and 49, each having a blowpipe the one running in the running direction of the material web 31 Gas stream 51 exits. The leadership facility 45 is designed as a baffle, the Material web 31 facing and preferably one acute angle with this or the web running direction enclosing surface 53 substantially parallel to that facing the material web 31 Surface 55 of the scraper 35 runs. This makes a more uniform, that is, -in Direction of travel of the material web 31 seen the same wide gap between the scraper 35 and the guide device 45 formed by the web of material 31 with the aid of the nozzle devices 37, 39, 47, 49 is performed safely. The material web 31 practically carried by the gas flows, with a web twisting preferably completely, at least be prevented as far as possible can. Those used for the transfer, in the direction of travel the gas streams 43, 51 running in the material web account for the largest share of the total volume of all the for the transfer of the material web / Threading strip used gas flows.

When starting up the paper making machine or a web break becomes a threading strip from a cutting device, not shown the material web 31 cut off. The threading strip together with the conveyor belt 25 the lower row led around the drying cylinder 11 and depends on its scope. The conveyor belt 25 is before the threading strip from the Surface of the drying cylinder 11 is lifted, via the deflection roller 27 to the next drying cylinder 13 of the bottom row. The one on the Drying cylinder 11 sticking threading strips from that emerging from the nozzle device 37 Gas stream 41 detached from those from the nozzle devices 39, 47 and 49 exiting gas streams 43 respectively 51 through the transfer area between the drying cylinder rows and in the closing nip between the conveyor belt 17th and the drying cylinder 5 of the top row. The threading strip is between the conveyor belt 17 and the drying cylinder 5 around this led around. This also applies to the drying cylinders 5, 7, 9 the top row is the conveyor belt 17 each lifted from a drying cylinder and onto the transferred to the next drying cylinder in the same row, So here first from the drying cylinder 5 the drying cylinder 7.

As can be seen from Figure 1, is to transfer of the threading strip from a drying cylinder top row to a drying cylinder of the bottom Row, for example from the drying cylinder 5 to Drying cylinder 13, only a scraper 35 used, that detaches the threading strip as well this also in the area between the rows of drying cylinders leads and stabilizes. One on the opposite side of the web Transfer device in the sense of the guide device 45 is not provided here.

The deflecting rollers 19, 21, 23, 27, 29 of the drying group 3 are arranged symmetrically, that is, the axes of rotation of the deflection rollers 27, 29 of the lower Dryer cylinder rows are each in an imaginary arranged vertically in the plane also an axis of rotation of a drying cylinder the top row, here the drying cylinder 5 or drying cylinder 7. Furthermore the axes of rotation assigned to the top row Deflection rollers 19, 21, 23 each in an imaginary, arranged vertically, in the same plane an axis of rotation of a drying cylinder of the lower one Row lies. Of course, the scraper 35 and the guide device 45 also within a dryer group are used, the deflection rollers have an asymmetrical arrangement, which are offset to the drying cylinders. Independently of the arrangement of the guide rollers preferably provided that all drying cylinders a scraper 35 is assigned to dryer group 3, the both as a known cleaning scraper or can be designed as a transfer scraper. To a compact design of dryer group 3 too realize, the scraper 35 is preferably as transfer scraper because it is a more compact Has construction as a cleaning scraper and in particular is shorter.

The blowpipes of the nozzle devices 37, 39, 47, 49 can by means of a control unit, not shown are activated and deactivated individually, what is referred to as driving in the following becomes. It is also possible to use a scraper To control 35 arranged blowpipes together, several blowpipes, for example two to twenty blowguns, or all blowguns inside to control dryer group 3 together. The Blowpipes can also each have a separate air volume adjuster have and / or about each a separate solenoid valve can be controlled. Farther the blowguns can be delayed, so activated and deactivated in succession, preferably depending on the position of the free End of the threading strip within the dryer section, so that to guide and stabilize the amount of air required relative to the threading strip is low.

Figure 2 shows schematically a side view of a Part of an embodiment of the drying group 3. The same parts have the same reference numerals provided so that in this respect to the description of Figure 1 is referenced. The deflecting rollers 21 and 29 the upper and the lower row of drying cylinders are arranged asymmetrically here That is, the axis of rotation of the deflecting roller 21 is relative the one in an imaginary, vertical Plane axis of rotation of the drying cylinder 13 offset to the left, as well as the axis of rotation of the Deflection roller 29 compared to that shown in Figure 1 Position is shifted to the left. From the in a free train from the drying cylinder 5 to the Drying cylinder 13 and from this to the drying cylinder 7 guided material web 31 and the over Deflection roller 21 guided conveyor belt 17 is a limited space 57, also known as a pocket, one for severing a threading strip from the material web 31 serving cutting device 59 and the scraper 35 are arranged. The cutting device 59 is at a cross across the Width of the material web 31 extending traverse 61 arranged and can be moved on this. The traverse 61 becomes - in the running direction of the material web 31 seen - aligned behind the scraper 35 arranged. This completely covers the traverse 61 from, thereby advantageously depositing prevented from material scraps on the crossmember 61 becomes. In addition, the transfer process will not with special needs. Thus, on the one hand, a high level of functional reliability the cutting device 59 ensures will. On the other hand, by the arrangement the cutting device 59 in the free space 57 Length of dryer section 1 can be reduced. The Cutting device 59 shown here serves to a threading strip when starting the machine for threading the material web into one of the dryer groups subordinate assembly of the manufacturing machine provide. It is therefore preferred arranged at the end of dryer group 3.

In the embodiment shown in Figure 2 the dryer group 3 is after commissioning the paper making machine or after one Web break the complete material web 31 in the Drying group 3 to the drying cylinder 13 of the lower one Row led. The material web 31 runs together with the conveyor belt 25 from the drying cylinder 13 from. This places on the scraper 35 attached nozzle device 37 or their Gas flow 41 ensures that the web of material is not adhere to the outer surface of the drying cylinder 13 remains, but together with the conveyor belt 25 expires. The deflecting roller 29 over which the conveyor belt 25 is carried out in the in FIG illustrated embodiment positioned such that the conveyor belt 25 only in the transfer area between the lower and the upper Row of drying cylinders separated from the material web 31 becomes. This shortens the free move, so that overall improved leadership is achieved becomes. In the area of free movement, the Cutting device 59 a threading strip from the Material web 31 cut off around the drying cylinder 7 and on through the rest of the dryer section led and then the subsequent assembly is fed. On the cutting device 59 opposite side of the web here is one Guide device 45 arranged, the first Material web 31 and then the separated one Entry strips and the remaining web securely to the Drying cylinder 7 transferred and stabilized in the process.

In another embodiment, the Cutting device 59 - seen directly in the direction of web travel another assembly of the manufacturing machine for example a treatment facility downstream, that is, the cutting device 59 is arranged at the end of the dryer section, so that the threading strip respectively the material web after passing the cutting device 59 led out of the dryer section and is transferred to the subsequent assembly.

Figure 3 shows a on a greatly enlarged scale Part of a dryer section 1, namely a drying cylinder 13 and a deflecting roller 29 of a drying group 3 '. Parts that correspond to those in FIGS and 2 match, have the same reference numerals provided so that in this respect on their description with reference to Figures 1 and 2. in the The following is just the construction of a scraper 35 'explained in more detail. This lies on the scope of the drying cylinder 13 and serves on the one hand one at the start of the paper making machine around the drying cylinder 13 threading strips on the guide roller 29 and on Direction of a drying cylinder, not shown respectively. On the other hand, the scraper 35 ' a winding of material scraps and scrap after a train ride. There are several on the scraper 35 ' here a total of three nozzle devices 37 ', 39 'and 63 attached. The first nozzle device 37 '- seen in the direction of travel of the material web 31 - is the foremost nozzle device and comprises one blow pipe having at least one single nozzle, from which a gas flow indicated by an arrow 41 exits. Through the bundled blowing with the inexpensive single nozzle to a limited Area of the drying cylinder can be the material web can be removed particularly well from its scope. A wedge-shaped cover can be assigned to the individual nozzle that shields the gas stream 41 or conducts, so that this exactly at the desired location on the drying cylinder. The gas flow 41 is opposite to the running direction the material web 31 directed and includes the surface 55 facing the material web 31 of the scraper 35 'an angle α in the range from -10 ° to 30 °, but preferably in the range of -5 ° to 15 °. With a negative angle denotes a direction of the gas flow 41 which is against the surface 55 of the scraper 35 'directed is. The gas flow 41 hits the surface of the Drying cylinder 13 and peels the threading strip when this is on the surface of the drying cylinder 13 sticks.

The subsequent nozzle device, viewed in the direction of web travel 63 has a slot nozzle Blower pipe from which a gas stream 65 emerges. The gas stream 65 closes with the surface 55 of the scraper 35 'an angle β which is in the range is from 140 ° to 180 °, preferably in the range from 155 ° to 175 ° is selected. The gas flow 65 is therefore essentially in the running direction of the material web 31 directed. Through the slot nozzle generates a preferably even gas curtain, so that twisting the web of material, respectively of the threading strip can be safely avoided can.

The two nozzle devices 37 'and 63 are preferred arranged next to each other at a very short distance and are in the area of the front, edge of the scraper resting on the drying cylinder 13 35 '. On the opposite, the drying cylinder 13 facing away edge of the scraper 35 ' the nozzle device 39 'is arranged which is a blowpipe from which a gas stream 43 emerges. Of the Gas stream 43 serves to thread the streak of the lower row of drying cylinders to the upper row of drying cylinders to be transferred and is aligned in such a way that he was at an acute angle the material web 31 strikes. The gas stream 43 closes with an upper side 67 of the scraper 35 ' an angle δ in the range of 90 ° to 150 ° can be and which is preferably an angular range from 100 ° to 130 °. The top 67 of the scraper 35 'closes here with that of the material web 31 facing surface 55 of the scraper 35 'an angle µ, which is approximately 75 °. Possibly can also on the nozzle device 39 ' and / or the nozzle device 63 can be dispensed with. Their use depends on the material web properties, especially from their moisture.

By counter to the running direction of the material web 31 directed gas flow 41 of the nozzle device 37 ' the threading strip is removed from the surface of the Drying cylinder 13 peeled off and against the surface of the conveyor belt 25 before the Threading strip runs onto the scraper 35 '. Due to the essentially in the running direction of the material web 31 directed gas flows 65 and 43 will the threading strip in the transition area between the drying cylinder rows accelerated and tightened and finally to the subsequent drying cylinder guided. Above the web guide roller 29 can a guide device explained with reference to Figure 1 45 are provided, the gas flow essentially in the direction of travel of the material web runs. The material web 31 is thus on both sides supported by a gas stream, causing a particularly safe transfer is possible.

The orientation or setting of the Gas flows from the nozzle devices 37, 39, 47, 49, 63 takes place via a blow gun, not shown the clamping device fixing the nozzle devices. This enables a stepless angle adjustment the blowguns.

It is clear from everything that by means of the Figures 1 to 3 described, defined distribution the gas flows of the threading strips are particularly safe can be transferred and stabilized. This is first of all by means of the gas stream 41 Surface of the drying cylinder detached and in the area of free movement between the lower and the upper row of drying cylinders between the gas flow 43 of the nozzle device 39 or 39 'and the gas flow 51 of the guide device 45. By guiding the material web 31 between two Gas flows can be a low-interference transfer of the Threading strips are ensured. The for the threading of the threading strip Components are inexpensive and universal for any dryer sections can be used. Particularly advantageous is that existing dryer sections, which is a conventional conveyor belt guide with the scraper 35 or 35 ' and the guide device 45 can be retrofitted can.

Claims (7)

Machine for the production of a material web, in particular paper or cardboard web, with a dryer section which has at least one two-row dryer group, which comprises an upper and a lower row of heatable drying cylinders, each of which is assigned a conveyor belt, which the drying cylinders of a row and the drying cylinders assigned deflection rollers revolves in a meandering manner, the material web being alternately guided around a drying cylinder of the upper row and around a drying cylinder of the lower row and between the drying cylinder rows in a free pass, and with at least one first nozzle device serving to transfer a threading strip, the gas flow of which essentially counteracts the running direction of the material web, characterized by a guide device (45) arranged on the material web side opposite the first nozzle device (37; 37 ') and comprising at least one second nozzle device (47, 49), whose gas flow (51) runs essentially in the running direction of the material web (31). Machine according to Claim 1, characterized in that the first nozzle device (37; 37 ') is attached to a scraper (35; 35') and in that the surface (55) of the scraper (35; 35 'facing the material web (31) ) and the surface (53) of the guide device (45) facing the material web (31) run essentially parallel to one another. Machine according to claim 1 or 2, characterized in that the guide device (45) is designed as a guide plate. Machine according to one of the preceding claims, characterized in that the surface (55) of the scraper (35; 35 ') facing the material web (31) extends at an angle to the direction of web travel. Machine according to one of the preceding claims, characterized by a cutting device (59) for separating a threading strip from the material web (31). Machine according to claim 5, characterized in that the cutting device (59) is arranged on a traverse (61) which extends at least substantially transversely across the width of the material web (31). Machine according to claim 6, characterized in that the crossmember (61), viewed in the direction of travel of the material web (31), is arranged flush behind the scraper (35; 35 ').

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