Classifications

• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21F—PAPER-MAKING MACHINES; METHODS OF PRODUCING PAPER THEREON
  • D21F1/00—Wet end of machines for making continuous webs of paper
  • D21F1/36—Guiding mechanisms
  • D21F1/42—Jets
• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21F—PAPER-MAKING MACHINES; METHODS OF PRODUCING PAPER THEREON
  • D21F5/00—Dryer section of machines for making continuous webs of paper
  • D21F5/02—Drying on cylinders
  • D21F5/04—Drying on cylinders on two or more drying cylinders
  • D21F5/042—Drying on cylinders on two or more drying cylinders in combination with suction or blowing devices
• • 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

Definitions

• the present invention relates to a method and device for guiding a paper web or the like. In general, this concerns guiding the web with the aid of air jets.
• a paper web made from stock is a very long totality, which, in the various stages of papermaking, must be transported around, or between numerous rolls.
• the rolls are situated over the entire length of the paper machine, at both the wet and dry ends, and are especially numerous in the paper machine's drying section, in which the rolls, around which the paper web travels, are usually in two rows.
• the paper web breaks for one reason or another, or if some other disturbance occurs, the paper web must be fed again to travel through the machine.
• Most of the paper web coming from the wet end is led to the pulper and a powerful, sharp water jet, for example, is used to cut and thus separate from the web a so-called web-threading tail, which is then attempted to be threaded through the machine and, if this succeeds, the tail is widened so that finally the full-width web travels through the machine, and is reeled as completed paper after the drying section.
• Air jets are used for many purposes in paper machines. For example, air jets have been used to aid the separation of the paper web from a roll, while similarly air jets have also been used in many ways to guide the paper web.
• Finnish patent 114491 discloses an example of a solution using an air jet to guide a paper web travelling through a drying section, and particularly to guide it from one roll to another in the drying section for the purpose of threading a web- threading tail.
• the said patent describes a method for carrying a paper web, usually a web-threading tail, from one roll to another, over a route in which a felt does not support the tail.
• four air nozzles are generally used, two of which are located on one side of the web and two on the other. On each side of the web, one air nozzle blows air in a direction nearly opposite to the direction of travel of the web while another nozzle blows air in nearly the same direction as the direction of travel of the web. This is claimed to carry the web steadily to the next roll.
• the present invention is intended to create a method and device particularly for guiding the movement of a paper web simply and functionally.
• the intention is also particularly to position the web laterally in a sure manner.
• Figure 1 shows a side view of the general positioning of the invention for guiding a web
• Figure 2 shows a second embodiment of the invention as a view like that of Figure 1 ;
• Figure 3 shows one practical embodiment of the use of the invention in connection with a separation roll;
• Figure 4 shows the use of the embodiment of Figure 3 in a real operating environment.
• Figure 1 shows a general view of the operating principle of the device according to the invention.
• the web 1 no matter whether it is a paper web or some other web, arrives in the immediate vicinity of the device.
• the surface 2 is a suitable stop for the web 1.
• the surface 2 can be formed by, for example, the surface of a detaching blade.
• the surface 2 is at least as wide as the web being guided.
• Figure 1 shows that, under the surface 2, there is a duct 3, into which compressed air is led, running at essentially right angles to the direction of travel of the web 1.
• the air tries to leave the duct 3 through perforations or gaps 4 and 5.
• the air blown through these holes 4 and 5 is oriented in such a way that part of the airflow is oriented towards the arrival direction of the web 1 and part towards the departure direction of the web.
• the difference in the feed directions of the air fed from the duct 3 is less than 180 degrees. For reasons of clarity, in Figures 1 and 2 this difference is drawn to appear greater than it would be in a practical embodiment.
• the air jets (which are marked with arrows in the figures) from ducts 4 and 5 create a vacuum in the area between the blast points. This means in turn that the web tends to be pulled by the vacuum to move towards the surface 2 and possibly onto it thus sliding along the surface. In this way, the web also travels forward in a manner that is laterally both controllable and stable. Here the actual transportation of the web is not interfered with, but is handled using conventional technology.
• the positioning of the air-jet nozzles is very important in terms of the invention.
• the undisturbed transportation of the web in the manner shown by the invention cannot be achieved, if the ducts are formed ' with the aid of pipes that clearly rise above the surface 2. In such a case, the web would probably not travel at all along the surface between the air-jet nozzles.
• the nozzles are therefore placed directly on the surface 2, or in shoulders slightly below it, as described in the following.
• the relative strengths of the air jets can be easily controlled by adjusting the size of the flow ducts 4 and 5. Adjustment can also take place using a suitable control element, by means of which the cross-sectional area of at least one of the ducts 4 or 5 can be altered. Such control elements are not, however, drawn in the figures.
• Figure 2 shows the principle of a second embodiment. It differs from the first embodiment only in that air is fed to the ducts 4 and 5 from different feed ducts 3 and 6. Each duct 3 and 6 can be adjusted separately relative to the flow, for which reason it is also very easy to implement adjustment of the mutual strengths of the air jets discharging from the ducts 4 and 5.
• the shape of the surface is in no way restricted to that shown.
• the shape of the surface may even vary very greatly, according to its intended purpose.
• the essential factor is that there are no protrusions hindering movement in the area between the air jets, but instead the construction permits the web to move smoothly.
• the surface must not allow any substantial amount of air to pass through it, so as avoid endangering the creation of the vacuum.
• FIG. 3 shows the use of the principle according to the invention in connection with a detaching blade 7.
• the detaching blade surface 8 is positioned against the roll, from which it is wished to detach the web.
• the airflows fed by the air ducts 3 and 6 from holes 4 and 5 create a vacuum between them, so that the web detaching from the roll becomes guided by the vacuum.
• the holes 5 are located in a shoulder 11.
• the ducts 4 also terminate in a kind of shoulder 12.
• FIG. 4 shows a practical application, in which a detaching blade 7, which is attached to frame structures 10 suitable for this purpose, is detaching the web from a roll 9.
• the edge 8 of the blade lies against the surface of the roll 9.
• Compressed air fed to ducts 3 and 6 discharges from perforations at the points shown by the arrows.
• the vacuum sucks the web into its grip at about the point shown by the triangular arrow and the web is guided in a stable manner to the next location.
• the web travels in a known manner over very many rolls, so that there are numerous locations at which it must be guided.

Landscapes

• Paper (AREA)
• Advancing Webs (AREA)

Applications Claiming Priority (2)

Publications (2)

Family

ID=36950658

Family Applications (1)

Country Status (7)

Families Citing this family (6)

Citations (6)

Family Cites Families (7)

• 2006
  • 2006-08-25 FI FI20060757A patent/FI20060757L/fi not_active Application Discontinuation
• 2007
  • 2007-08-24 BR BRPI0715731-2A2A patent/BRPI0715731A2/pt not_active IP Right Cessation
  • 2007-08-24 EP EP07803699.3A patent/EP2057315A4/de not_active Withdrawn
  • 2007-08-24 US US12/310,349 patent/US20090242156A1/en not_active Abandoned
  • 2007-08-24 WO PCT/FI2007/000209 patent/WO2008023090A1/en active Application Filing
  • 2007-08-24 CN CNA2007800351415A patent/CN101517160A/zh active Pending
  • 2007-08-24 CA CA002661542A patent/CA2661542A1/en not_active Abandoned

Patent Citations (6)

Non-Patent Citations (1)

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