Classifications

• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21G—CALENDERS; ACCESSORIES FOR PAPER-MAKING MACHINES
  • D21G9/00—Other accessories for paper-making machines
  • D21G9/0063—Devices for threading a web tail through a paper-making machine
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
  • B65H—HANDLING THIN OR FILAMENTARY MATERIAL, e.g. SHEETS, WEBS, CABLES
  • B65H20/00—Advancing webs
  • B65H20/10—Advancing webs by a feed band against which web is held by fluid pressure, e.g. suction or air blast
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
  • B65H—HANDLING THIN OR FILAMENTARY MATERIAL, e.g. SHEETS, WEBS, CABLES
  • B65H2301/00—Handling processes for sheets or webs
  • B65H2301/50—Auxiliary process performed during handling process
  • B65H2301/52—Auxiliary process performed during handling process for starting
  • B65H2301/522—Threading web into machine
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
  • B65H—HANDLING THIN OR FILAMENTARY MATERIAL, e.g. SHEETS, WEBS, CABLES
  • B65H2406/00—Means using fluid
  • B65H2406/30—Suction means
  • B65H2406/32—Suction belts
  • B65H2406/322—Suction distributing means
  • B65H2406/3221—Suction distributing means for variable distribution in the direction of transport
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
  • B65H—HANDLING THIN OR FILAMENTARY MATERIAL, e.g. SHEETS, WEBS, CABLES
  • B65H2801/00—Application field
  • B65H2801/84—Paper-making machines

Definitions

• the invention relates to a device for guiding a material web strip in a running direction with a housing in which a Unterchristerzeugungseinrich- device is arranged.
• a paper web During its production and processing, a paper web must be guided through various processing devices, including a dryer section, a press section, a calender and optionally a spreading or a sizing device. This is often done in this way that at the edge of the paper web a strip of material web having a width of the order of 200 to 300 mm is cut and this strip first passes through the processing device. As soon as this material strip has reached the point where it can be pulled onto it, the paper web is cut to width so that it can pass through the corresponding processing device in full width.
• an air-permeable belt usually runs around a housing on which the material web lies.
• the tape is supported on a plate provided with holes or slots.
• a negative pressure is generated, so that the web strip is sucked on the other side of the tape.
• the invention has for its object to guide a strip of material safely.
• the holding force which is composed of surface area and negative pressure, is in many cases still too low to securely hold the material web strip in total.
• this unstable situation only lasts for a short time, because the web of material continues to run and then covers the next or next chambers in the running direction, so that the negative pressure located there also acts on the web of material.
• the holding force acting on the material web strip is thus constructed in sections.
• a first vacuum chamber in the direction of travel of the material web strip has a larger number of suction devices than a vacuum chamber arranged behind it in the direction of travel of the material web strip.
• This makes it possible to generate a higher negative pressure in the first vacuum chamber, as long as the web of material web has not yet completely covered this vacuum chamber.
• the highest negative pressure occurs when the first vacuum chamber is completely covered by the material web strip. After the material web strip is stabilized in this way over the first vacuum chamber, a lower negative pressure is sufficient to transport the web strip to the end of the device. Since the vacuum chambers are gradually covered and then act with full negative pressure on the web strip, the holding force on the air-permeable belt at the end of the device is very large. Slippage of the material web strip is reduced or even prevented.
• the ineursenaug sensoryen are designed as suction nozzles.
• Suction nozzles are easy to install. They are supplied with compressed air, so that even the energy required for sucking energy can be provided in a simple manner.
• a boundary wall is filled with suction in the first vacuum chamber.
• this wall for example the bottom of the vacuum chamber, is completely or at least almost completely covered with suction devices.
• the suction devices are not only the openings through which the suction air is sucked out of the vacuum chamber, but also the elements that surround the suction openings. By having one accordingly large number of suction devices provides, which are distributed over the boundary wall, the negative pressure can be generated so to speak flat.
• the vacuum chambers preferably have a guide side along which the material web strip runs and a bottom opposite the guide side, the suction devices acting through the bottom.
• This embodiment has the advantage that the contaminants are sucked towards the bottom and can then be removed by the suction devices. In the long term practically no dirt can accumulate in the vacuum chamber. This applies regardless of whether the device is operated so that the web strip is guided in the direction of gravity above or below it. It is important in this context that the air flow can be sucked so to speak straight from the dirt causing side in the opposite side.
• the guide side and the bottom are parallel to each other.
• the vacuum chambers thus have a constant height in the direction of travel. This simplifies the production.
• the guide side and the bottom have a spacing in the range of 5 to 35 mm, in particular in the range of 10 to 20 mm.
• the volume of the vacuum chamber on the one hand kept so small that you with an acceptable cost can generate sufficient negative pressure relatively quickly.
• the suction means are arranged symmetrically with respect to a central axis which is parallel to the running direction.
• the negative pressure relative to the central axis can be generated symmetrically, which also contributes to a stabilization of the material web strip on the air-permeable belt. If you have only one suction device, such as a suction nozzle in the vacuum chamber, then this ⁇ augdüse is divided by the central axis. If you have two suction nozzles in the vacuum chamber, then these are arranged symmetrically on both sides of the central axis.
• At least two adjacent vacuum chambers are separated by a partition, which at least partially encloses an angle to the direction of rotation, which is greater than 95 ° or less than 85 °.
• the partition extends at least in sections at an angle ⁇ 90 ° to the direction.
• the partition has two legs which are inclined in opposite directions to the running direction. Preferably, these two legs are inclined in the direction of travel. This in turn results in symmetrical conditions, which has a favorable effect on the stabilization of the material web strip.
• the legs collide in a V-shape.
• the partition has two substantially straight sections so that it is easy to manufacture. As soon as the material web strip passes over the top of the "V" with its beginning, it is also subjected to negative pressure by the following vacuum chamber.
• the partition extends in the direction of both sides of the suction device.
• the incardiaug shark is thus positioned relatively close behind the partition, so that the negative pressure can act relatively early on the web strip, so almost immediately when the web has been passed over the partition wall. This results in conditions after only a short time, through which the material web strip can be stably guided.
• the partition wall is V-shaped, then the suction device is located, as it were, in the gusset of the "V".
• the housing preferably has an intermediate wall delimiting the vacuum chamber. This makes it possible to keep the volume of the vacuum chambers small. The smaller the volume, the faster the air in it can be sucked off and the negative pressure built up. The amount of negative pressure is thus not appreciably affected. You no longer have to empty the entire housing to create the vacuum.
• the intermediate wall is formed trough-shaped with inclined side walls.
• the inclined side walls contribute to a reduction in the volume. On the other hand, they also help to remove dirt particles or water, which penetrate into the vacuum chamber, to the suction devices out.
• the side walls are inclined in the direction of gravity to the suction towards.
• a compressed air supply line for the suction nozzles between the housing and the intermediate wall is arranged.
• This compressed air supply line is therefore in any case not visible within the device and does not bother. Also, the risk of it being damaged is reduced.
• a vacuum chamber has a volume of at most 2 1, in particular at most 1 1, on.
• One such a small volume can be sucked out relatively quickly, so that even webs of material running along the web, which, for example, have a speed of the order of magnitude of 1,800 m / min, can be kept stable very quickly.
• At least one vacuum chamber is divided into at least two compartments parallel to the running direction. This is preferably the first vacuum chamber in the direction of travel. If the material web strip is cut out of the material web, then it may happen that it does not come to rest exactly in the middle of the vacuum chamber. In this case, there is a risk that it does not completely cover the vacuum chamber, so that side air can still be sucked in, whereby the holding force is reduced. If you divide the vacuum chamber parallel to the running direction in at least two compartments, then the chance is great that at least one of these compartments is completely covered by the material web strip. At least in this compartment of the web strip is then held with full force.
• each compartment is limited in the direction of travel by a V-shaped partition wall. This results in the advantages that have been described above in connection with a vacuum chamber in general.
• the V-shaped partition does not create a dead zone when the web of material passes over the partition. Rather, when crossing the separation wall then acted upon by the negative pressure in two adjacent compartments in the direction.
• FIG. 1 is a perspective view of an apparatus for guiding a web strip in the open state
• FIG. 2 is a plan view of the device of FIG. 1,
• Fig. 3 is a section III-III of FIG. 2 and
• Fig. 4 is a sectional view through a suction nozzle.
• a device 1 for guiding a material web strip not shown in detail in a running direction 2 has a housing 3 which is provided at its front end with a deflection roller 4 and at its rear end with a deflection roller 5.
• a drive pin 6 is provided for the guide roller 5 at the rear end, to which a drive motor not shown in detail can be connected.
• an air-permeable belt is performed, which is not shown for reasons of clarity in the drawing.
• This band may be formed, for example, as a sieve.
• the housing 3 has a cover plate, also not shown, which is provided with openings, for example in the form of slots. The cover plate has been omitted in order to be able to present details of the interior of the device 1.
• the air-permeable tape lies on the cover plate.
• the web strip which is acted upon by the cover plate and the air-permeable belt with negative pressure and thus firmly trapped on the outside of the air-permeable belt.
• Each partition wall 13-17 has in plan view a V-shape, that is, two legs 18, 19, which extend at an angle of approximately 45 ° to the running direction 2.
• Each vacuum chamber 7-12 is provided with at least one suction device in the form of a suction nozzle 20a-20e, 21-25.
• the first suction chamber 7 in the running direction 2 has a larger number of suction nozzles 20a-20e than the vacuum chambers 8-12 located further back in the running direction 2.
• the first vacuum chamber 7 has five suction nozzles 20a-2oee. But it is also possible to provide the first vacuum chamber 7 only with three or four suction nozzles.
• the suction nozzles 20-25 are arranged in a bottom 26 of the vacuum chamber 7-12.
• the floor 26 is a grenzungswand, which is opposite to a guide side 27, along which the web strip is guided.
• On the guide side 27 is the air-permeable belt, on which the material web strip is located (not shown).
• the bottom 26 and the guide side 27 are parallel to each other with a distance in the range of 5 to 35 mm, preferably with a distance in the range of 10 to 20 mm.
• the respective suction nozzle 21-25 is arranged so that it is relatively close to the partition wall 13-17, so that it is still surmounted in the direction 2 on both sides of the respective partition wall 13-17.
• the suction nozzle 21-25 is, so to speak, in the "gusset 11 of the" V ".
• the housing 3 has an intermediate wall 28, which delimits the vacuum chambers 7-12.
• the intermediate wall 28 has two inclined side walls 29, 30 which are inclined in the direction of the suction nozzles 20-25. If the device 1 is arranged as shown in FIG. 3, ie, the material web strip is guided in the direction of gravity above the housing 3, then dirt particles or water droplets entering the vacuum chambers 7 - 12 will pass through Side walls 29, 30 directed towards the suction nozzle 20-25 so that they can be easily removed ' . The same applies, however, in an operation "overhead", because even then creates an air flow, the dirt particles on the side walls 29, 30 and the bottom 26 ab vitamint.
• Fig. 4 shows schematically a suction nozzle 23 in section.
• the suction nozzle 23 has a compressed air inlet 31 through which compressed air can be injected.
• the suction nozzle 23 also has a suction inlet 32.
• the compressed air entering through the compressed air inlet 31 passes through a gap between the differently hatched parts of the suction nozzle 23 and then flows out through an outlet 33. It tears suction air, which has entered through the suction inlet 32, with.
• the suction nozzle 23 operates on the venturi principle.
• the volume of Unterdruckkairanern 7-12 is kept small. It is possible to configure the intermediate wall 28 such that each vacuum chamber 7-12 has a volume of approximately 2 l or less, for example 1 l.
• a compressed air supply line 34 is arranged in the housing 3 and between the intermediate wall 28 and the actual housing wall, so that the Druckluftver- sorgungs effet 34 does not interfere to the outside in appearance.
• the compressed air supply line 34 is connected in each case via a branch line 35 with the respective suction nozzles 20-25.
• a vacuum chamber 7-12 has a length in the direction of 2 of about 300 mm. At a web speed of 1,800 m / min, it takes about 1/100 second until a vacuum chamber 7-12 is covered by the web strip. Depending on the setting, a suction nozzle has a suction power of, for example, 4,500 l / min, so that about 1/5 second of approximately 0,75 l of air can be sucked out of each vacuum chamber 7-12. If the vacuum chamber 7-12 has a volume of 1 to 2 l, then the material web strip is reliably held as soon as it has run over a vacuum chamber 7-12. In order to build up the necessary negative pressure, it is not necessary to remove all the air from the vacuum chamber 7-12.
• the material web strip is simultaneously acted upon by a negative pressure in two adjacent vacuum chambers 7-12 when it is conveyed in running direction 2, as soon as he starts to cross a partition 13-17. This avoids dead zones. It is also helpful here that the suction nozzles 21 - 25 are arranged relatively close behind the dividing walls 13 - 17 so that the substance produced thereby can be arranged. Pressure can also act relatively quickly on the web strip.
• the suction nozzles 20-25 open at practically the level of the bottom 26. In any case, they are arranged so that air is sucked through the bottom. This has a significant advantage for the self-cleaning effect of the device. When fibers, dust or water accumulate in the vacuum chambers 7-12, these contaminants are sucked by the suction nozzles 20-25 and blown out on the bottom of the device 1.
• a zone i. a vacuum chamber 7-12 has a length of the order of 250 to 400 mm. Depending on how long you want to lead the web strip, then you have to switch more or less vacuum chambers 7-12 in a row.
• the first negative pressure chamber 7 in the running direction 2 for example, it is possible to generate a negative pressure of 28 mbar. In the subsequent vacuum chambers 8-12 then a negative pressure of 5 to 20 mbar is sufficient.
• the suction nozzles 20-25 are arranged symmetrically with respect to a central axis 36. Thus, if a vacuum chamber 8-12 has only one suction nozzle 21-25, then this suction nozzle 21-25 is divided by the central axis 36. If, as in the first vacuum chamber 7, more
• Suction nozzles 20a-20e are provided, then these sym- arranged metric to the central axis 36.
• pressure conditions can be realized in the vacuum chambers 7-12, which are also symmetrical to the central axis 36. A displacement of the material web strip by different pressures is virtually ruled out.
• each compartment is provided with its own suction nozzle 20-25, the first compartment of each row in the direction of running in turn having more suction nozzles than the downstream units.

Landscapes

• Physics & Mathematics (AREA)
• Fluid Mechanics (AREA)
• Advancing Webs (AREA)
• Registering, Tensioning, Guiding Webs, And Rollers Therefor (AREA)
• Replacement Of Web Rolls (AREA)
• Chutes (AREA)

Applications Claiming Priority (2)

Publications (2)

Family

ID=39620127

Family Applications (1)

Country Status (5)

Families Citing this family (1)

Family Cites Families (3)

• 2007
  • 2007-05-18 DE DE102007023215A patent/DE102007023215A1/de not_active Withdrawn
• 2008
  • 2008-04-25 CA CA2687551A patent/CA2687551C/fr active Active
  • 2008-04-25 AT AT08749731T patent/ATE478194T1/de active
  • 2008-04-25 EP EP08749731A patent/EP2147151B1/fr active Active
  • 2008-04-25 DE DE502008001169T patent/DE502008001169D1/de active Active
  • 2008-04-25 WO PCT/EP2008/055069 patent/WO2008141890A1/fr not_active Ceased

Non-Patent Citations (1)

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