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

Definitions

• the invention relates to a guiding device for conveying a web threading tail in a fiber web machine, the guiding device including at least one guide plate and an air channel as well as openings arranged on the wall limiting the air channel for forming air blows which follow the travel direction of the web threading tail and are directed to the surface of the guide plate facing the web threading tail and thereby conveying the web threading tail, and the guide plate being adapted as an integral part of the air channel and the openings being formed in the base material of the guide plate.
• the invention also relates to a fiber web machine.
• the guiding device is a pipe constituting an air channel with openings arranged on its wall for forming air blows. So called blow plates also exist, the operation of which is also based on air blows .
• Blow pipes alone are mainly used only for guiding the web threading tail approximately. Instead, a blow plate is provided with a guide plate, on which a vacuum effect is created by air blows by means of a so called Coanda effect.
• the web threading tail tends to follow the surface of the guide plate while air blows following the travel direction of the web threading tail simultaneously convey the web threading tail forward.
• the openings open up to a shoulder which is arranged between the air channel and the blow plate.
• air blows are oriented substantially parallel to the blow plate. In operation, air blows create a vacuum effect, however, at the same time, significant friction is generated as the web threading tail passes the shoulder. Then a major part of the transfer force of air blows is lost.
• the web threading tail is detached from the surface of the guide plate, whereby compensating air is later- ally conveyed between the web threading tail and the guide plate. As the web threading tail is forwarded further, more and more compensating air is absorbed.
• the object of the invention is to provide a novel device for conveying a web threading tail in a fiber web machine, having a simpler and lower construction than before and providing a threading efficiency higher than before with a smaller air volume and/or a lower pressure level than earlier.
• Another object of the invention is to provide a novel fiber web machine in which the conveying of a web threading tail is smoother and more reliable as well as modifiable in a more versatile way than heretofore.
• the characteristic features of this device according to the invention are that the angle ⁇ between the blow direction of the openings and the guide plate is 5 - 30°, more advantageously 10 - 20°, and the distance of the openings from the front edge of the guide plate is 10 - 50 mm, more advantageously 10 - 25 mm.
• the guiding device according to the invention is provided with small openings, such as holes or slits, in a very small angle relative to the plane surface of the guide plate.
• small openings such as holes or slits
• pressurized air flowing from an opening that opens up to the plane surface is already almost in a correct direction, that is, following the transport direction of the web threading tail.
• Another remarkable feature is the location of openings in the initial part of the guide plate together with a straight support surface.
• a place is created, in which the air flow takes hold of the web threading tail, at one position of a slit nozzle or a row of holes extending crosswise over the plane surface.
• the web threading tail is maintained in control and the air blow following the plane surface conveys the web threading tail further, simultaneously reducing harmful lateral movements and other migration and thereby calming down the travel of the web threading tail.
• the openings open up to the guide plate instead of a shoulder, the friction phenomenon which has caused problems earlier is avoided.
• access of compensating air between the web threading tail and the guide plate is avoided.
• an air blow forwards the web-like material faster than before.
• the present force can be achieved with an air volume smaller than before or at a pressure level lower than earlier. Since the guide plate is a part of the air channel, the manufacture of the guiding device is easier. At the same time, the construction of the guiding device becomes light and low, yet rigid.
• Figure 1 is a lateral view showing, in principle, a part of a position of a fiber web machine in which several guiding devices according to the invention are used for conveying a web threading tail,
• Figure 2a is an oblique front view of a first embodiment of the guiding device according to the invention
• Figure 2b is an oblique bottom view of the guiding device of
• Figure 3a is a horizontal sectional view of the guiding device of Figure 2a
• Figure 3b is an enlargement of a part of Figure 3a
• Figure 4 is a lateral view showing, in principle, a part of another position of a fiber web machine in which several guiding devices according to the invention are used for conveying a web threading tail,
• Figure 5 is an oblique rear view of a second embodiment of the guiding device according to the invention with some of the guide plates removed,
• Figure 6 shows a third embodiment of the guiding device according to the invention.
• Figure 1 is a lateral view of a size press 10 of a fiber web machine.
• Fiber web machines include, for example, paper and board machines. Size pressing is here based on the film transfer technology. A starch-containing solution is applied to the surface of the rolls 11 and 12 as a thin film, which is transferred to the fiber web in the roll nip. The fiber web is brought to size pressing from the dryer section preceding it, and after size pressing, the fiber web is here led to an addi- tional dryer section via air driers 13 and 14. In the exemplifying embodiment, when starting the tail threading procedure, the fiber web is transported down to broke treatment at the end of the dryer section.
• a web threading tail 15 is cut from the fiber web and the forwarding of the tail is started with, for example, a vacuum belt conveyor.
• the web threading tail 15 of Figure 1 is brought to the lead roll 16 by some means wherefrom the web threading tail 15 is fast and reliably transported via the size press 10 and air dryers 13 and 14, using equipment composed of several guiding devices according to the invention.
• the roll nip has been opened by moving the upper roll 12, and the air dryers 13 and 14 have also been moved to an open position, for enabling tail threading.
• a guiding device according to the invention can also be located, for example, at the tail threading of coating stations and calenders, which can be long and include confined spaces. The guiding device can thus be used in the other sections of a fiber web machine as well. During the production, at least some of the guiding devices are moved to a rest position.
• a fiber web machine thus includes one of more guiding devices 17 for conveying a web threading tail.
• One guiding device 17 according to the invention is shown in Figures 2a and 2b.
• the guiding device 17 includes at least one guide plate 18 and an air channel 19 as well as openings 21 arranged on the wall 20 limiting the air channel 19, for forming air blows which follow the travel direction of the web threading tail 21 and are directed to the surface 22 of the guide plate 18 facing the web threading tail.
• the air blows both keep the web threading tail in control and transport it forward.
• the air blows combined with the surface of the guide plate provide a vacuum effect, whereby the web threading tail tends to follow the guide plate.
• the air blows push the web threading tail forward.
• the guide plate 18 is adapted as an integral part of the air channel 19 and the openings 21 are formed in the base material of the guide plate 18.
• the construction of the guiding device is extremely simple and low.
• openings arranged in an inclination open up to the plane surface, thus preventing access of compensating air between the web threading tail and the guide plate. Consequently, the volume of air conveyed along with the web threading tail is a fraction compared to prior art, and tail threading can thus be successfully performed even via confined spaces.
• the guiding device 17 fits, for example, between the rolls 11 and 12 and the subsequent air dryers 13 and 14 of Figure 1.
• the guide plate 18 is a substantially straight plane surface.
• the guide plate is planar and straight from the beginning to the end.
• a guide can be used for deviating the web threading tail.
• the purpose is to detach the web threading tail and simultaneously change its direction.
• a planar guide plate is also simple to manufacture. In particular, onwards from the compensating air openings, over the blow openings, a substantially straight portion of 150 mm is pro- vided without angles or evident protrusions. The planarity of the guide plate is ⁇ 2 mm and any deviations are small over the entire distance.
• a part of the air channel 19 is composed of an open profile 23, which is hermetically fastened, at the position of the openings 21, to the surface 24 of the guide plate 18 which is opposite to the surface 22 facing the web threading tail.
• Figure 2b has a U profile while Figure 5 has a V profile. Both are advantageously standard profiles, which further simplifies the manufacture.
• the profiles are advantageously fas- tened to the bottom surface of the guide plate by welding. Then the profiles additionally stiffen the guide plate, thus making separate frame constructions redundant.
• plastic profiles can be fastened by gluing, in which case it may be necessary to use separate support constructions .
• two functional guide plates have been formed from one plate component.
• the thickness of the sheet material is 3 mm and the sheet material is stainless steel.
• the guiding device can be manufactured in the following way, for example. A suitable piece is cut from a sheet material by laser cutting, for example, and the edges of the guide plate are bent as reinforcements. Subsequently, using a shank end mill, for example, an incision 25 is machined to that surface 24 of the guide plate 18 which is opposite to the surface 22 facing the web threading tail, in which incision an opening 21 is formed with the same shank end mill, for example.
• FIG. 3b shows in more detail the incision 25, which can extend from one edge of the guide plate 18 to the other or it can be machined at the position of the openings only. After this, the leading edges of the guide plates are formed.
• the incision and the openings can also be machined before bending the guide plate edges. It is also possible to utilize composite materials, plastics, wood materials, metal, or their combinations .
• the thickness of the material can be in the range of 2 to 10 mm for a construction composed of one or more layers; for example, two sheets set on top of each other, in which case the splice joint gap of the lower sheets replaces the groove milled for bores.
• a chamber 27 which turns away from the surface 22 facing the web threading tail is provided at the leading edge 26 of the guide plate 18, in the travel direction of the web threading tail . This ensures that the web threading tail is reliably guided onto the guide plate.
• a gap 28 from which the air of the previous air blow can be discharged with- out causing the web threading tail to enter the gap is also simultaneously created between two successive guide plates.
• the chamber also slightly guides the compensating air to the following air blow preventing the web threading tail from being absorbed in contact with the guide plate to chafe it.
• the radius of the chamfer is 15 mm and the chamfer turns down by 60°.
• the guiding device may include several successive guide plates, each provided with an air channel of its own including openings.
• one guiding device 17 incorporates four guide plates 18, which are fastened to the profiles and each other to form a self-supporting construction, here advantageously by means of a longitudinal air connection.
• the profiles distribute the air volume evenly to the openings.
• the profiles are connected to each other with a pipe or another closed profile.
• a functional manifold is provided, which simultaneously acts as a longitudinal reinforcement.
• the transverse profiles are hermetically fastened to the longitudinal profile by welding, after which the transverse profiles are welded to the guide plate, thus completing the guiding device.
• the pipe 29 is provided with a hole 30, and a hole 31 slightly larger than this has been made in the U profile.
• a hermetical weld 32 is provided in the junction of these holes.
• Another hermetical weld 33 is provided between the U profile and the guide plate 18.
• the air pressure led to the pipe 29 is distributed to the U profile and, via the openings 21, further to the surface 22 of the guide plate 18 facing the web threading tail, to form air blows.
• the guiding device can be bracketed directly from the longitudinal profile, for example, using a bracket 34 as shown in Figure 5, which can be fastened to different points in the longitudinal profile.
• the brackets can also be more than one in number.
• Air pressure is led to the manifold via a hose, for example, which allows moving and/or turning the guiding device from the rest position to the tail threading position and vice versa.
• the height of the guiding device 17 of Figure 2a is less than 50 mm with the manifold.
• Figure 6 shows a third embodiment of the guiding device in which articulation means 35 are provided between the guide plates 18 for changing the mutual angle of the guide plates 18.
• articulation means 35 are provided between the guide plates 18 for changing the mutual angle of the guide plates 18.
• four of the center-most guide plates are rigidly supported to each other to form a plane surface.
• one guide plate 18, turnably supported by the articulation means 35 is provided on the inlet side.
• two guide plates 18 are present.
• the articulation means ensure sufficient rigidity while the construction of the guiding device remains simple at the same time.
• the articu- lation means are lockable, which permits maintaining the desired position during the operation.
• the articulation means are additionally dismountable, which permits to manufacture an individual guiding device of one type, achieving in this way, if necessary, even long and configurable equip- ment, by combining the required number of guiding devices.
• Figure 6 shows longitudinal manifolds which are connected with a flexible hose for distributing air pressure to the air channels (not shown) . Flexible hoses enable to change the mutual angle between the guide plates equipped with articulation means.
• a fiber web machine may include one of more guiding devices for conveying a web threading tail in a fiber web machine.
• several guiding devices 17 are provided in succession such that versatile and reliably operating equipment is formed for conveying the web threading tail.
• the guiding devices are detached from each other so that an air blow that has lost its kinetic energy can be discharged prior to the following guiding device.
• the guiding device is arranged in connection with a restricted interval 36, such as between the rolls 11 and 12 of Figure 1. Despite the narrow gap, the web threading tail travels on the surface of the guide plate.
• Known guiding devices based on air blows are completely inoperable in such positions.
• there are in fact four device complexes comprising a total of twenty guiding devices.
• the guiding device operates even upside down, and the web threading tail can be reliably transferred from one apparatus to another.
• the web threading tail 15 is shifted three times from one apparatus to another.
• Figure 4 shows another arrangement in which the web threading tail turns the travel direction. Due to the reliable operation of the guiding device according to the invention, the web threading tail is maintained in control without fluttering, enabling the route proposed, which has also been tested in operation.
• the novel operation additionally enables to set up the guiding devices in an angle relative to each other.
• the incident angle a of the web threading tail, arriving from a preceding roll and the guiding device 17, is 0 - 15°.
• the web threading tail can arrive at the guiding device even in an angle, nevertheless remaining in control of the air blows .
• the incident angle a is approximately 13°.
• the angle between successive guide plates can be notably larger than the angle mentioned above .
• the openings 21 are formed in the base material of the guide plate 18 and the angle ⁇ between the blow direction of these openings 21 and the guide plate is 5 - 30°, more advantageously 10 - 20°.
• the angle ⁇ is 15°.
• the openings open up to the surface 22 of the guide plate facing the web threading tail, in which case harmful shoulders are avoided.
• the guide plate is smooth without any shoulders or other protrusions which would generate friction.
• air blows set in a suitable angle firstly create a sufficient vacuum effect and secondly, efficiently forward the web-like material .
• the distance of the openings 21 from the front edge of the guide plate is 10 - 50 mm, more advantageously 10 - 25 mm.
• This dimension refers to the straight portion of the guide plate excluding the chamfer.
• the novel design and the placement of openings enable to manufacture, on one hand, very short, and on the other hand, also very long guiding devices.
• the dimension of the guide plate 18 in the travel direction of the web-like material is 100 - 500 mm, more advantageously 200 - 400 mm.
• This dimension refers to the effective dimension obtainable with one air channel.
• the openings 21 are composed of holes 37.
• air blows are formed without separate nozzles. Holes are easy to machine with a shank end mill, for example, particularly when utilizing an incision.
• Plastic and plastic composite materials are also possible. According to the invention, relatively small, straight holes are used, having a 5 diameter of 1 - 3 mm, more advantageously 1.5 - 2.5 mm. Then air consumption remains moderate and pressure losses are small. In Figure 3b, the diameter of the hole 37 is 1.6 mm. In addition, separate nozzles are unnecessary.
• the distance between the holes is selected to suit each particular case. Generally, the distance between the holes is 10 - 50 mm, more advantageously 10 - 25 mm, such that the larger the holes, the further away they are from each other.
• the holes can be arranged 15 imbricately or slantwise, for example, for directing the vacuum effect in a desired way.
• the dimension of the center area is 200 mm and the holes are at a distance of 10 mm.
• the edge areas are 50 mm wide and the holes are at a distance of 25 mm.
• the middle openings of the guide plate can be larger than the openings in the edge areas (not shown) . In this way, an enhanced blow effect can be provided in
• the area of enhanced air blows can range from one third to two thirds of the blow width of the device, advantageously it is about a half of the blow width, however, less than the width of the web threading tail.
• a guiding device 17 equipped with an area of enhanced air blows is shown in Figure 2a, in which the web threading tail is illustrated with a dot-and-dash line.
• An area of enhanced air blows can also be formed with slits while the holes are in the edge areas, or vice versa.
• the openings can also be formed of slits, which can be worked with a laser. Slits create extremely uniform air blows and, in addition, the noise of air discharging from slits is lower compared to holes.
• the slit width can be 0.05 - 1 mm, more advantageously 0.1 - 0.5 mm. Slits can also be located in a straight line or suitably imbricately arranged, thus achieving a comprehensive and uniform air blow.
• the length of the slits depends mainly on case-specific requirements and the slit width. Discontinuous slits are longer than 5 mm, advantageously longer than 10 mm. A slit can also be continuous, having a width that is almost equal to the entire guiding device. In this case the slit width is approximately 200 - 300 mm, even as wide as 400 mm in particularly wide applications.
• the guiding device Due to the simple design and low friction, highly variable pressures can be applied in the guiding device.
• the guiding device, and particularly the openings are dimensioned in such a way that a pressure of 0.25 - 7, more advantageously 0.5 - 2 bar, can be applied. Then remarkable forces transferring the web threading tail can be achieved already at a low pressure.
• a high pressure can also be used, which can be utilized particularly for achieving a sufficient flow speed.
• the device can be used in fast fiber web machines as well.
• the dimensioning of the guiding device according to the invention can vary in different applications. However, openings opening up to the surface of the guide plate facing the web threading tail, with which earlier friction problems are avoided, are essential.
• the web threading tail can be reliably transferred from one device to another, which allows forming long equipment with a complex route.
• the guiding device according to the invention is also operable in fast fiber web machines with the production speed thereof exceeding 2000 meters per minute.
• An air blow arriving from the plane surface in a small angle provides a firm hold without the web threading tail contacting the guide plate.
• the web threading tail precisely follows the surface of the guide plate without fluttering and wandering.
• air blows can be formed even in a completely planar guide plate, obtaining optimal angles relative to the guide plate.
• the web threading tail can be controllably forwarded without the traditional friction problem.
• the construction of the guiding device is also remarkably simple and small in dimensions.
• the guiding device can be located in confined positions as well, with the bracketing remaining light.
• the web threading tail is kept in control for the entire duration of the threading procedure without the web threading tail floating irregu- larly somewhere in the vicinity of the guiding device.

Landscapes

• Paper (AREA)
• Registering, Tensioning, Guiding Webs, And Rollers Therefor (AREA)
• Treatment Of Fiber Materials (AREA)
• Braiding, Manufacturing Of Bobbin-Net Or Lace, And Manufacturing Of Nets By Knotting (AREA)
• Preliminary Treatment Of Fibers (AREA)

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Applications Claiming Priority (2)

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Citations (7)

• 2010
  • 2010-06-02 FI FI20105619A patent/FI123352B/fi active IP Right Review Request
• 2011
  • 2011-05-30 DE DE212011100105U patent/DE212011100105U1/de not_active Expired - Lifetime
  • 2011-05-30 CN CN2011900005236U patent/CN203200595U/zh not_active Expired - Lifetime
  • 2011-05-30 WO PCT/FI2011/050496 patent/WO2011151514A1/en active Application Filing

Patent Citations (7)

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