Implingement drying unit and a dryer section

• US 20040049940A1
• Filed: 09/29/2003
• Published: 03/18/2004
• Est. Priority Date: 11/06/2000
• Status: Active Grant

• Current Assignee: Valmet Technologies OY (Valmet Oyj)
• Original Assignee: Metso Paper Incorporated (Neles Oyj)
• Inventors: Salminen, Martti, Juppi, Kari, Komulainen, Antti, Kurki, Matti, Kaihovirta, Juha, Kuhasalo, Antti
• Granted Patent: US 7,036,242 B2
• Time in Patent Office: Days
• US Class Current: 34/114
• CPC Class Codes: D21F 5/00 Dryer section of machines for making continuous webs of paper
• CPC Class Codes: D21F 5/04 on two or more drying cylinders
• CPC Class Codes: D21F 5/18 Drying webs by hot air

Abstract

An apparatus for a dryer section of a paper or board machine[, which comprises] has a drying group (R) and an impingement drying unit (10) which is placed above and/or below a row (DSR) of drying cylinders (3)[and in which a]. A drying fabric (1) supported paper or board web (2) [has been arranged to be]is conducted past the impingement drying unit [while supported by a drying fabric (1), such as a wire or equivalent. The invention is characterised in that the impingement drying unit (10) comprises] (10) having at least one impingement surface (IP1, IP2) the side profile of which is straight, changeably curved in its radius of curvature, in the shape of a broken line or a selectable combination of these, and that the impingement surface or a tangent line to the impingement surface or a line passing via the beginning and the end of the impingement surface or an extension of [said] the line forms on the impingement side an angle with a horizontal plane parallel to the machine level, which angle is ≦120[°]°, advantageously [in a range of 120°-60°]120°-60°, most advantageously about 90[°]°.

Claims

1. An impingement drying unit for a dryer section of a machine making a fibrous web, advantageously a paper or board machine, which comprises at least one drying group (R) and an impingement drying unit (10) in which the fibrous web (2), advantageously a paper or board web, i.e. a web, has been arranged to be conducted past the impingement drying unit while supported by a drying fabric (1), such as a wire or equivalent, characterised in that the impingement drying unit (10) extending at least partly above or below a horizontal plane which passes through the uppermost or lowermost drying cylinder(s) (3) of the drying group (R) and being parallel to the machine level, comprises at least one impingement surface or face (IP1, IP2) the side profile of which is straight, changeably curved in its radius of curvature, in the shape of a broken line or a selectable combination of these, and that the impingement surface or a tangent to the impingement surface or a line passing via the beginning and the end of the impingement surface or an extension of said line forms on the impingement side an angle of ≦

120°

with a horizontal plane parallel to the machine level.

2. An impingement drying unit according to claim 1, characterised in that at least one impingement drying device (101, 102, 103) of the impingement unit (10) extending at least partly below or above a row (DSR) of drying cylinders (3) acts on at least one impingement surface (IP1, IP2), which is defined by the outer surface of the drying fabric (1) running in the impingement drying unit, in which connection impingement acts directly on the web (2), and that the impingement surface is arranged at least partly in a substantially upright position below and/or above the row (DSR) of the drying cylinders (3) such that:

the angle between a line passing along or a tangent line to or a line passing via the beginning and the end of at least one impingement surface of the impingement drying unit;

or a line passing along or a tangent line to or a line passing via the beginning and the end of at least one part or run section (21, 211, 212;

22, 221, 222) or portion of a run section of the impingement surface of the impingement drying unit;

or

the centre-line or the symmetry line (K) of the impingement drying unit;

and a horizontal plane parallel to the machine level, is in a range of 120°

-60°

on the side of impingement.

3. An impingement drying unit according to claim 2, characterised in that

the angle between the line passing along or the tangent line to or the line passing via the beginning and the end of at least one impingement surface of the impingement drying unit, or

the line passing along or the tangent line to or the line passing via the beginning and the end of at least one part or run section (21, 211, 212;

22, 221, 222) or portion of a run section of the impingement surface of the impingement drying unit, or

the centre-line or the symmetry line (K) of the impingement drying unit and a horizontal plane parallel to the machine level, is about 90°

.

4. An impingement drying unit according to any one of claims 1 to 3, characterised in that the impingement drying unit (10) includes a first impingement surface (IP1) and a second impingement surface (IP2), that the first impingement surface includes for the web (2) a first run section (21, 211, 212) in which the web runs in a direction away from the drying group (R) and in which the web is supported by the wire (1) from the side opposite to impingement, and that the second impingement surface includes for the web a second run section (22, 221, 222) in which the web runs towards the drying group and in which the web is supported by the wire on the side opposite to impingement.

5. An impingement drying unit according to any one of claims 1 to 4, characterised in that the side profile of the first and the second impingement surface (IP1, IP2) is substantially:

straight;

curved;

in the shape of a broken line formed of successive parts which are at an angle to one another;

or a selectable combination of said side profile shapes.

6. An impingement drying unit according to any one of claims 1 to 5, characterised in that the line passing along or the tangent line to or the line passing via the beginning and the end of both the first and the second impingement surface (IP1, IP2) is on the side of impingement at an angle to the horizontal plane parallel to the machine level, which angle is ≦

120°

, advantageously in a range of 120°

-60°

, most advantageously about 90°

.

7. An impingement drying unit according to any one of claims 1 to 5, characterised in that the first impingement surface and the second impingement surface (IP1, IP2) are substantially parallel.

8. An impingement drying unit according to any one of claims 1 to 7, characterised in that the centre-line (K) of the impingement drying unit (10) coincides with the symmetry line of the impingement surfaces (IP1, IP2) of the impingement drying unit, in which connection the angle between the centre or symmetry line and the horizontal plane parallel to the machine level is about 90°

.

9. An impingement drying unit according to any one of claims 1 to 8, characterised in that the impingement drying device (101, 102, 103) is outside a wire loop (11), and that means for supporting and guiding the run of the wire (1) and the web (2), including support rolls (13), rolls and/or vacuum devices and/or suction rolls and/or blow/suction boxes (16) attaching the web (2) to the wire (1) by the suction effect, are inside the wire loop on the side of the wire (1) substantially opposite to the impingement drying device.

10. An impingement drying unit (10) according to any one of claims 1 to 9 for a drying group (R) of a dryer section, characterised in that the impingement drying device (101, 102, 103) and the drying group (R) have a common wire loop (11), and that the impingement drying device constitutes a part of at least one drying group of the dryer section.

11. An impingement drying unit (10) according to any one of claims 1 to 9 for a drying group (R) of a dryer section, characterised in that the impingement drying unit (101, 102, 103) is provided with a wire (1) of its own, which forms the wire loop (11), and that the impingement drying unit is a separate impingement drying unit which is disposed between two drying groups (R) or in front of a drying group or after a drying group.

12. A dryer section of a machine making a fibrous web, advantageously a paper or board machine, which comprises at least one drying group (R) applying single-wire draw or twin-wire draw and an impingement drying unit (10) for drying the fibrous web, advantageously a paper or board web, i.e. a web (2), and a drying fabric (1), such as a wire or equivalent on whose support the web has been arranged to be conducted past the impingement drying unit, characterised in that the impingement drying unit (10) extending at least partly above or below a horizontal plane which passes through the uppermost or lowermost drying cylinder(s) (3) of the drying group (R) and being parallel to the machine level, comprises at least one impingement surface or face (IP1, IP2) the side profile of which is straight, changeably curved in its radius of curvature, in the shape of a broken line or a selectable combination of these, and that the impingement surface or a tangent line to the impingement surface or a line passing via the beginning and the end of the impingement surface or an extension of said line forms, on the side of impingement, an angle of ≦

120°

with a horizontal plane parallel to the machine level.

13. A dryer section according to claim 12, characterised in that in the impingement drying unit (10) extending at least partly below or above a row (DSR) of drying cylinders (3) in the dryer section, at least one impingement drying device (101, 102, 103) acts directly on at least one impingement surface (IP1, IP2), which is defined by the outer surface of the drying fabric (1) running in the impingement drying unit, in which connection impingement acts directly on the web (2), and that the impingement surface is arranged at least mainly in a substantially upright position such that:

the angle between a line passing along or a tangent line to or a line passing via the beginning and the end of at least one impingement surface of the impingement drying unit;

or a line passing along or a tangent line to or a line passing via the beginning and the end of at least one part or run section (21, 211, 212;

22, 221, 222) or portion of a run section of the impingement surface of the impingement drying unit;

or

the centre-line or the symmetry line (K) of the impingement drying unit;

and a horizontal plane parallel to the machine level, is on the side of impingement in a range of 120°

-60°

.

14. An impingement drying unit according to claim 13, characterised in that the angle between the line passing along or the tangent line to or the line passing via the beginning and the end of at least one impingement surface of the impingement drying unit, or

the line passing along or the tangent line to or the line passing via the beginning and the end of at least one part or run section (21, 211, 212;

22, 221, 222) or portion of a run section of the impingement surface of the impingement drying unit, or

the centre-line or the symmetry line (K) of the impingement drying unit

and a horizontal plane parallel to the machine level, is about 90°

.

15. A dryer section according to any one of claims 12 to 14, characterised in that the impingement drying unit (10) includes a first impingement surface (IP1) and a second impingement surface (IP2), that the first impingement surface includes for the web (2) a first run section (21, 211, 212) in which the web runs in a direction away from the drying group (R) and in which the web is supported by the wire (1) from the side opposite to impingement, and that the second impingement surface includes for the web a second run section (22, 221, 222) in which the web runs towards the drying group and in which the web is supported by the wire from the side opposite to impingement.

16. A dryer section according to any one of claims 12 to 15, characterised in that the side profile of the first and/or the second impingement surface (IP1, IP2) is substantially:

straight;

curved;

in the shape of a broken line formed of successive parts which are at an angle to one another;

or a selectable combination of said side profile shapes.

17. A dryer section according to any one of claims 12 to 16, characterised in that the first and second impingement surfaces (IP1, IP2) are on the side of impingement with a horizontal plane parallel to the machine level at least partly, which is ≦

120°

, advantageously in a range of 120°

-60°

, most advantageously about 90°

.

18. A dryer section according to any one of claims 12 to 17, characterised in that the first impingement surface and the second impingement surface (IP1, IP2) are substantially parallel.

19. A dryer section according to any one of claims 12 to 18, characterised in that the centre-line (K) of the impingement drying unit (10) coincides with the symmetry line of the impingement surfaces (IP1, IP2) of the impingement drying unit, in which connection the angle between the centre or symmetry line and the horizontal plane parallel to the machine level is about 90°

.

20. A dryer section according to any one of claims 12 to 19, characterised in that the impingement drying device (101, 102, 103) is outside a wire loop (11), and that means for supporting and guiding the run of the wire (1) and the web (2), including support rolls (13) and/or rolls or vacuum devices and/or suction rolls and/or blow/suction boxes (16) attaching the web to the wire by the suction effect, are inside the wire loop on the side of the wire substantially opposite to the impingement drying device.

21. A dryer section according to any one of claims 12 to 19, characterised in that the impingement drying unit (10) and the drying group (R) have a common wire (1) to form a wire loop (11), in which connection the impingement drying unit constitutes a part of at least one drying group of the dryer section.

22. A dryer section according to any one of claims 12 to 19, characterised in that the impingement drying unit (10) is provided with a wire (1) of its own, which forms the wire loop (11), and that the impingement drying unit is a separate impingement drying unit which is disposed between two drying groups (R) or in front of a drying group or after a drying group.

23. A dryer section according to any one of claims 12 to 22, characterised in that there are several impingement drying units (10) in the drying group (R) or in connection with the drying group.

24. A dryer section according to any one of claims 12 to 23, characterised in that the impingement drying units (10) are disposed alternately above and below a row (DSR) of drying cylinders (3) or

some of the impingement drying units (10) are disposed below a row of drying cylinders (3) and the other impingement drying units are disposed above a row of drying cylinders 3,

in which connection the web (2) can be dried from both sides thereof.

25. A dryer section according to any one of claims 12 to 24, characterised in that there is at least one impingement drying unit (10) in at least one drying group (R) or in connection with at least one drying group.