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EP-4464483-B1 - BLOW LINE AND METHOD FOR TRANSPORTING FIBERS SUSPENDED IN STEAM AS WELL AS AN STAGE OF EXPANSION SET FOR SAID BLOW LINE

EP4464483B1EP 4464483 B1EP4464483 B1EP 4464483B1EP-4464483-B1

Inventors

  • MATTSSON, Marcus

Dates

Publication Date
20260513
Application Date
20230515

Claims (17)

  1. Blow line for transporting fibers in a duct, whereas the fibers are suspended in steam and are moving in the blow line (10) respectively the duct as a steam-fiber stream (6) with a higher pressure than the ambient pressure, said duct preferably arranged in a fiber processing plant, comprising at least one tube (5) with a bend (1) for guiding the steam-fiber stream (6) along a curve with a rotation angle (32) for separating steam (21) radially inward in the tube (5) from said steam-fiber stream (6) flowing radially outwards along the curve, said tube (5) comprising in direction of the flow an inlet (2) for the steam-fiber stream (6) before the curve of the bend (1) and an outlet (3) after the curve of the bend (1) for delivering a steam reduced steam-fiber stream, wherein an opening (4) for the separated steam (21) is arranged radially inwards in the wall of the tube (5), that the opening (4) is arranged in the direction of the flow with a determined distance (24) before the outlet (3), that the opening (4) is within the curve of the bend (1) and/or along the rotation angle (32) of the curve and that the plane of the permeable diameter of said opening (4) is essentially arranged parallel to the direction of the flow of the stream (6).
  2. Blow line according to claim 1, characterized in that the opening (4) is arranged in direction of the flow in the last third of the curve of the bend (1) or the rotation angle (32).
  3. Blow line according to any of the preceding claims, characterized in that the opening (4) is circular, oval, elliptic or a grove, preferably linear or bent.
  4. Blow line according to any of the preceding claims, characterized in that the cross section of the bend (1) is at least partially circular, oval, elliptic, trapezoidal or omega-shaped, wherein preferably the smallest or shortest length of the geometry is arranged radially inwards whereas the larger or longer length of the geometry is arranged radially outwards to enhance the separation by preparing the fibers more space radially outwards.
  5. Blow line according to any of the preceding claims, characterized in that at least the curve of the bend (1) and/or at least a part of the cross section is arranged as cast and/or has been cast out of cast iron.
  6. Blow line according to any of the preceding claims, characterized in that in direction of the flow before and/or after the bend (1) transition pieces (7, 8) and/or transition areas (8*) adjacent to the inlet (2) or the outlet (3) are arranged to connect the bend (1) with the blow line (10) or follow up transporting means, especially to adapt different cross sections and/or to adapt changes of the trajectory.
  7. Blow line according to any of the preceding claims, characterized in that the bend (1) is split or arranged along the direction of the flow in at least two parts, a shape (15) and a cover (16), which are preferably connected with a positive mechanical engagement, like bolts (16).
  8. Blow line according to claim 8 , characterized in that the cover (16) in view of the cross section perpendicular to the direction of the flow is essentially planar whereas the shape (15) is essentially arranging the permeable diameter for the steam-fiber stream.
  9. Blow line according to any of the preceding claims 8 or 9, characterized in that the geometry of the cross section of the shape (15) is a trapezoid, an omega-shape or a hemicycle, whereas the connection of the shape with the cover is forming the tube and whereas preferably by a trapezoidal shape the opposite surface to the smallest edge of a trapezoidal shape is arranged by the cover and/or the opening is in the smallest edge.
  10. Blow line according to any of the preceding claims 8 or 10, characterized in that the cover (16) is arranged as an interchangeable wear and tear part.
  11. Blow line according to any of the preceding claims, characterized in that the area of the opening (4) of the tube (5) is thickened, especially to receive a bore for the opening (4) and/or a basic part as a connector for the transfer of the steam (21) with other means.
  12. Blow line according to any of the preceding claims, characterized in that at the opening (4) a flange (29), a valve, a rinsing system for the opening and/or a replaceable sleeve for adjusting the diameter (30) of the opening is arranged, said valve is preferably implemented as on/off-valve, a full bore valve and/or an 100% open valve.
  13. Blow line according to any of the preceding claims, characterized in that the tube (5) and/or the bend (1) is integrally moulded and preferably including the flanges for the inlet, the outlet and/or the area of the opening.
  14. Blow line according to any of the preceding claims, characterized in that the tube (5) and/or the bend (1) have arranged a window to be covered by the cover (14) and that preferably at the cover (14) for such a window in the tube (5) and/or the bend (1) is arranged with an external protrusion (34) to be inserted in the window frame (35) as to avoid hindrances or turbulences especially in the direction of the flow at the end of such a window.
  15. Method for transporting fibers in a duct of a blow line, whereas the fibers are suspended in steam and are moving in the blow line (10) respectively the duct as a steam-fiber stream (6) in a higher pressure than the ambient pressure, said duct preferably arranged in a fiber processing plant, comprising at least one tube (5) with a bend (1) for guiding the steam-fiber stream (6) along a curve with a rotation angle (32) for separating steam (21) radially inward in the tube (5) from said steam-fiber stream (6) flowing radially outwards along the curve, said tube (5) comprising in direction of the flow an inlet (2) for the steam-fiber stream (6) before the curve of the bend (1) and an outlet (3) after the curve of the bend (1) for delivering a steam reduced steam-fiber stream (22), wherein the separated steam (21) from the steam-fiber stream (6) is let out of the bend (1) via an opening (4) arranged radially inwards in the wall of the tube (4), said let out is arranged before the steam reduced steam-fiber stream (6) is reaching the outlet (3) and is conducted along the curve of the bend (1) and/or along the rotation angle (32) of the curve and that the plane of the permeable diameter of said opening (4) is essentially parallel to the direction of the flow of the stream (6).
  16. Stage of expansion for a blow line comprising a bend with or without transition pieces to be connected onto a blow line in which fibers are suspended in steam and are moving in a duct of the blow line (10) as a steam-fiber stream (6) with a higher pressure than the ambient pressure, said duct preferably arranged in a fiber processing plant, said stage of expansion comprising at least one tube (5) with a bend (1) for guiding the steam-fiber stream (6) along a curve with a rotation angle (32) for separating steam (21) radially inward in the tube (5) from said steam-fiber stream (6) flowing radially outwards along the curve, said tube (5) comprising in direction of the flow an inlet (2) for the steam-fiber stream (6) before the curve of the bend (1) and an outlet (3) after the curve of the bend (1) for delivering a steam reduced steam-fiber stream (22), wherein an opening (4) for the separated steam (21) is arranged radially inwards in the wall of the tube (5), that the opening (4) is arranged in the direction of the flow with a determined distance (24) before the outlet (3), that the opening (4) is within the curve of the bend (1) and/or along the rotation angle (32) of the curve and that the plane of the permeable diameter of said opening (4) is essentially arranged parallel to the direction of the flow of the stream (6).
  17. Stage of expansion for the preceding claim, characterized in that the stage of expansion is installable in an existing blow line with a certain central axis (11) by cutting out a determined part of the blow line (10) and that by using at least two transition pieces (7) and the bend (1) the trajectory of the stream is at least partially different in reference to the central axis (11) of the blow line (10).

Description

OBJECT OF THE INVENTION The present invention relates to a blow line for transporting fibers in a duct, whereas the fibers are suspended in steam and are moving in the blow line respectively the duct as a steam-fiber stream with a higher pressure than the ambient pressure, said duct preferably arranged in a fiber processing plant, according to claim 1. The present invention further refers to a method for transporting fibers in said blowline according to claim 15 and an stage of expansion set for said blow line according to claim 16. BACKGROUND OF THE INVENTION EP 2 213 431 A2 discloses a bend, a blow line, and a fiberboard plant. In this known fiberboard plant, a refiner makes fibers out of wood chips by using high-pressure steam and rotating refiner discs. The high-pressure steam blows the fibers out into the blow line resulting in a steam-and-fibers stream which the blow line guides to the dryer. Depending on the size and design of the fiberboard plant, the blow line may have a length of up to 100 m. A gluing system might be part of the blow line and is used to inject atomized glue into the steam-and-fibers stream. The dryer is preferably a tube dryer, and the blow line extends into the tube of the tube dryer so that the outlet of the blow line empties into the dryer and ejects the steam-and-fibers stream into the hot, dry air in the tube. Due to the moisture contained in the steam of the steam-and-fibers stream, the drying of the fibers is quite energy consuming. EP 2 855 108 B1 discloses a bend for such a blow line, in which the fibers and the steam are separated a stripper or separator using an direction change of the steam-and-fibers stream in a part of the tube used as blow line. The direction change is mainly arranged by a curve or bend of the tube. At the end of the direction change the tube is splitting up into two separate tubes, whereas the separate tubes are arranged radially to the center of rotation of the curve of the tube and in doing so the radially inner tube is used for the steam and the radially outer tube is receiving the concentrated and squeezed steam-and-fiber-stream. It so happens that the reduction of steam and the concentrated remaining steam-and-fiber-stream is helpful in saving energy as less steam has to be dried and removed from the steam-fiber-stream before it is possible to use the produced fibers in a dry process. Even in a wet-process less energy is necessary. The mentioned innovations and systems have been accepted in the industry but still the performance can be improved and the energy consumption can be further reduced. Furthermore such bends or curves in high pressure usage underlay certain regulations and have to be checked regularly. The production and commissioning of such a high pressure system needs a close supervision and safety certificates. SUMMARY OF THE INVENTION It is an object of the present invention to reduce the energy consumption in a fiberboard plant or another fibers-processing plant, such as a pulp mill or a board mill. It is a further objective of the invention to provide a safe apparatus which is less costly than the mentioned systems before and can be maintained more efficiently. Furthermore a stage of expansion should be provided to enhance blow lines and their energy consumptions avoiding costly rearrangements in the plants. Last but not least a stage of expansion should be able to allow an operating company of a plant with a blow line to rearrange a blow line more easily especially by adding a bend according to the invention with the possibility for a separation of steam in the blow line. The pressure difference from the pipe of the blow line to the ambient pressure is usually more than three bars, mostly more than 5 to 10 bars. There might be blow lines with an even higher pressure for transporting the steam-fiber stream. The object of the invention is solved by the solutions of claims 1, 15 and 16. Regarding the blow line the invention emanates from an blow line for transporting fibers in a duct, whereas the fibers are suspended in steam and are moving in the blow line respectively the duct as a steam-fiber stream with a higher pressure than the ambient pressure, said duct preferably arranged in a fiber processing plant, comprising at least one tube with a bend for guiding the steam-fiber stream along a curve with a rotation angle for separating steam radially inward in the tube from said steam-fiber stream flowing radially outwards along the curve, said tube comprising in direction of the flow an inlet for the steam-fiber stream before the curve of the bend and an outlet after the curve of the bend for delivering a steam reduced steam-fiber stream. The problem is solved for a blow line or a bend, preferably a steam/fiber separator, by the features of independent claims, especially by an opening for the separated steam arranged radially inwards in the wall of the tube, by said opening arranged in the direction of the flow with a determined d