U.S. patent application number 13/384311 was filed with the patent office on 2012-05-24 for device for producing a fibrous web.
Invention is credited to Jorg Baubock, Rudolf Greimel, Harald Weigant.
Application Number | 20120125555 13/384311 |
Document ID | / |
Family ID | 43334377 |
Filed Date | 2012-05-24 |
United States Patent
Application |
20120125555 |
Kind Code |
A1 |
Greimel; Rudolf ; et
al. |
May 24, 2012 |
Device For Producing A Fibrous Web
Abstract
The invention relates to a device (1) for producing a pulp web
(3), comprising an impingement drying system (5) with a first
elongated impingement drying unit (7) and a second elongated
impingement drying unit (9) lying adjacent to the first unit. The
longitudinal axes (L) of the first and second impingement drying
units (7, 9) run at an angle of inclination of
35.degree.-55.degree., preferably 40.degree.-50.degree. and
especially preferably approximately 45.degree. in relation to a
horizontal plane (HE) and the respective longitudinal directions
(L) of the first and second impingement drying units (7, 9) run
vertically and horizontally in opposite directions starting from
their respective front sections (31, 33), or the respective
longitudinal directions (L) run vertically in opposite directions
starting from their respective front sections (31, 33) and
horizontally in the same direction.
Inventors: |
Greimel; Rudolf; (Stattegg,
AT) ; Baubock; Jorg; (Graz, AT) ; Weigant;
Harald; (Stattegg, AT) |
Family ID: |
43334377 |
Appl. No.: |
13/384311 |
Filed: |
June 23, 2010 |
PCT Filed: |
June 23, 2010 |
PCT NO: |
PCT/AT2010/000229 |
371 Date: |
January 16, 2012 |
Current U.S.
Class: |
162/308 ;
162/289 |
Current CPC
Class: |
D21F 5/185 20130101;
D21F 5/18 20130101 |
Class at
Publication: |
162/308 ;
162/289 |
International
Class: |
D21G 9/00 20060101
D21G009/00; D21F 5/00 20060101 D21F005/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 15, 2009 |
AT |
A1107/2009 |
Claims
1. A device (1) for producing a pulp web (3), transported by the
device (1) along a transport path (Tw), through an impingement
drying system (5), comprising: a first elongated impingement drying
unit (7) and a second elongated impingement drying unit (9)
adjacent to the first, where each drying unit has a longitudinal
axis (L) extending between a front section (31, 33) where the web
enters the drying unit and rear section (35 37) and two impingement
surfaces (11, 13; 15, 17) which are arranged on opposite sides of
the longitudinal axis (L) of the respective impingement drying unit
(7; 9) and where each has its own supporting fabric (19; 21) which
supports the pulp web (3) on one side from one side and each of
which has an impingement dryer (39; 41) pointed towards at least
one of the respective two impingement surfaces (11, 13, 15, 17) in
order to have a direct effect on the side of the pulp web (3)
facing away from the supporting fabric (19; 21), where the
longitudinal axis (L) of each of the first and second impingement
drying units (7, 9) is arranged at an angle of inclination of
35.degree.-55.degree., in relation to a horizontal plane (HE),
where the first and the second impingement drying units (7, 9) are
arranged facing one another with their front section (31; 33) when
viewed in longitudinal direction (L), and where the first and the
second impingement drying unit (7, 9) extend slanted vertically
beginning from their respective front section (31; 33) in their
respective longitudinal direction (L) in opposite directions.
2. Device (1) according to claim 1, wherein the longitudinal axis
(L) of the first impingement dryer (7) and the longitudinal axis of
the second impingement dryer (9) are arranged essentially parallel
to one another.
3. Device (1) according to claim 1, where the respective supporting
fabric (19; 21) of the first and the second impingement drying unit
(7; 9) runs in a convex arrangement in a transport path between the
two respective impingement surfaces (11, 13; 15, 17).
4. Device (1) according to claim 1 where the respective supporting
fabric (19; 21) of the first and second impingement drying unit (7;
9) circulates in an essentially convex loop.
5. Device (1) according to claim 1, including a press section (43),
where the impingement drying unit system (5) is arranged in the
transport path (Tw) directly after the press section (43).
6. Device (1) according to claim 1 including a dryer section (61)
with a plurality of drying cylinders (67), where the impingement
drying system (5) is arranged in the transport path (Tw)
immediately before the dryer section (61) or in the dryer section
(61) between the drying cylinders.
7. Device (1) according to claim 1, including a coating head for
introducing a medium, to the pulp web (3), and wherein the
impingement drying system (5) is arranged in the transport path
(Tw) directly after the coating head.
8. Device (1) according to claim 1, wherein the first impingement
drying unit (7) is arranged in the transport path before the second
impingement drying unit (9) and the first impingement drying unit
(7) extends from its front section downwards and to the rear on a
slant in relation to the horizontal plane (HE) in its longitudinal
direction (L).
9. Device (1) according to claim 1, wherein the impingement dryer
(39) of at least the first impingement drying unit (7) is pointing
towards both sides of the two respective impingement surfaces (11,
13) in order to have a direct effect on the side of the pulp web
(3) facing away from the supporting fabric and an indirect effect
through the supporting fabric (19) on the side of the pulp web (3)
which is covered by the supporting fabric (19).
10. Device (1) according to claim 1, wherein the supporting fabric
(19; 21) is a wire belt with openings.
11. Device (1) according to claim 1, wherein the pulp web (3) is
supporting continuously by the respective supporting fabric (19,
21) in the respective impingement drying unit (7; 9).
12. Device (1) according to claim 1, wherein several of said
impingement drying systems (5) are arranged one behind the other in
the transport path (Tw) and the longitudinal axes (L) of all
impingement drying units (7, 9, 73, 75) are arranged essentially
parallel to one another.
13. Device (1) according to claim 1, wherein the first and the
second impingement drying units (7; 9) each have a pulp web
receiving point (53; 57) at which the pulp web (3) is transferred
to the supporting fabric (19; 21) of the respective impingement
drying unit (7; 9), and the pulp web receiving point (53; 57) is
located in the front section (31; 33) of the respective impingement
drying unit (7; 9).
14. Device (1) according to claim 1, wherein the first and the
second impingement drying units (7, 9) each have a pulp web release
point (55; 59) at which the pulp web (3) is carried away from the
supporting fabric (19; 21) of the respective impingement drying
unit (7; 9), and the pulp web release point (55; 59) is located in
the front section (31, 33) of the respective impingement drying
unit (7, 9).
15. Device (1) according to claim 1, wherein the impingement
surfaces taper from the front section (31; 33) of the respective
impingement drying unit (7; 9, 73; 75), toward the rear
section.
16. Device (1) according to claim 1, wherein the first and second
impingement drying units (7; 9) extend vertically and horizontally
in opposite directions, or extend beginning from their respective
front section (31; 33) in their respective longitudinal direction
(L) vertically in opposite directions and horizontally in the same
direction.
17. Device (1) according to claim 2, wherein the pulp web (3) is
supporting continuously by the respective supporting fabric (19,
21) in the respective impingement drying unit (7; 9).
18. Device (1) according to claim 17, wherein the first and the
second impingement drying units (7, 9) each have a pulp web
receiving point (53, 57) at which the pulp web (3) is transferred
to the supporting fabric (19, 21) of the respective impingement
drying unit (7, 9), and the pulp web receiving point (53, 57) is
located in the front section (31, 33) of the respective impingement
drying unit (7, 9).
19. Device (1) according to claim 18, wherein the first and the
second impingement drying units (7, 9) each have a pulp web release
point (55, 59) at which the pulp web (3) is carried away from the
supporting fabric (19, 21) of the respective impingement drying
unit (7, 9), and the pulp web release point (55, 59) is located in
the front section (31, 33) of the respective impingement drying
unit (7, 9).
20. (1) according to claim 19, wherein the impingement surfaces
taper from the front section (31, 33) of the respective impingement
drying unit (7, 9, 73, 75), toward the rear section.
Description
[0001] The invention relates to a device for producing a pulp web,
such as a paper, board, or tissue web.
[0002] In the production of pulp webs, there is generally the
problem that the pulp web, which is sometimes very damp during the
production process, has to be dried gently in order to obtain the
desired paper quality. This is why dryer sections are used with a
plurality of heated drying cylinders arranged in one or two rows on
which the paper web rests, where the hot surfaces of the drying
cylinders cause the water in the paper web to evaporate slowly.
Here, however, there is the problem on the one hand that the still
very damp paper web sticks slightly to the surface of the drying
cylinders, particularly at the desired fast machine speed, and the
overall length of the production device or production machine is
greatly extended by the large number of drying cylinders arranged
one after the other in a row.
[0003] In view of this problem area, impingement drying devices
were suggested in the state of the art (see for example DE 199 44
266 A1, EP 1 156 155 A2, DE 10 2007 038 133 A1 or DE 10 2007 026
931 A1), where an impingement dryer with a blower hood is provided
to apply a dry medium, for example hot air, to the pulp web in
order to remove more water at times from the damp pulp web.
[0004] As a result of the invention, a device is created for
producing a pulp web which allows efficient drying of the pulp web
while requiring less installation space.
[0005] This is achieved by means of a device with the
characteristic features in claim 1. Further embodiments of the
invention are described in the dependent claims.
[0006] As the two impingement drying units lie adjacently opposite
one another according to the invention, that is to say with the
front sections adjacent to one another and facing one another,
respectively, where their longitudinal axes--either essentially
parallel or essentially at an angle of 90.degree. to one another
for example--extend at an angle of approximately 45.degree. to the
horizontal plane, the installation space, which is generally
available vertically above and below the device, and the horizontal
installation space are used uniformly in the vertical plane upwards
and downwards and in the horizontal plane. In addition, web
transfer from the first to the second drying unit can be effected
very gently in the variant with the longitudinal axes running in
parallel to one another. In addition, it is possible to receive the
web very gently with the front impingement drying unit in the
transport path (in which the impingement drying device is located)
by placing this front impingement drying unit in the transport path
on a slant, e.g. in the direction of the transport path (=to the
rear); here the pulp web is generally fed horizontally from a
preceding device in the transport path to the impingement drying
device so that there is an obtuse angle of 135.degree. facing to
the rear between the horizontally fed pulp web and the longitudinal
axis of the front impingement drying unit in the transport path on
account of the essentially 45.degree. angle of its longitudinal
axis, and this obtuse angle does not cause any severe deflection of
the pulp web. In this case, the rear impingement drying unit in the
transport path slants accordingly by 45.degree. in the opposite
direction to the transport path (forwards) or by 45.degree. in the
direction of the transport path (to the rear); in the former case,
web transfer can be effected particularly gently; the pulp web is
generally carried onwards essentially horizontally by the
impingement drying device so that there is also an obtuse angle of
approximately 135.degree. between the longitudinal axis of the rear
impingement drying unit in the transport path if this is slanting
forwards and the pulp web that is carried onwards horizontally. The
first and the second slanting impingement drying units and their
slanting longitudinal axes are essentially on a vertical plane; the
same applies to any further drying units that are arranged at a
corresponding slant and follow the first and second impingement
drying units.
[0007] According to the invention, the pulp web is also supported
in the area of the impingement surfaces on one side or only from
one side by the corresponding supporting fabric of the respective
impingement drying unit, which achieves effective drying because
the impingement medium impinges directly onto the pulp web. Here,
for example, the impingement dryer in each of the impingement
drying units is directed towards the side of each of the two
impingement surfaces facing away from the supporting fabric in each
case.
[0008] As described above, the impingement dryer of the respective
impingement drying unit can have a hood mounted above the
respective impingement surface in which an impingement medium, in
particular hot air for example, is blown onto the pulp web
supported by the supporting fabric. Hoods of this kind can be
provided per impingement surface on both sides of the pulp web so
that impingement medium can be applied to both of its sides. The
impingement dryer is designed preferably in such a way that the
impingement medium is applied to at least the sides of all
impingement surfaces that are not covered by the supporting fabric
because greater efficiency is achieved if the impingements medium
impacts the pulp web directly than if there is still a supporting
fabric in between.
[0009] In addition, the respective impingement dryer can be
designed in such a way that the impingement medium is also applied
to the side of the pulp web that is covered by the supporting
fabric; if the supporting fabric is completely closed, the effect
is then practically the same as that of a drying cylinder (only
heat transfer to the pulp web); if the supporting fabric has holes
or perforations, there are also convection effects on the side of
the impingement surface covered by the supporting fabric.
[0010] The impingement drying device according to the invention can
have several pairs of first and second impingement drying units
that are arranged in succession in the direction of the transport
path of the pulp web and adjacent to one another. In a preferred
embodiment, the impingement drying device has a further one to
three impingement drying units in addition to the first and second
impingement drying units, where the longitudinal axes of all
impingement drying units run essentially parallel to one another
and the longitudinal axes of the top impingement drying units run
essentially in parallel to one another and the longitudinal axes of
the bottom impingement drying units run essentially parallel to one
another with an angle of approximately 90.degree. between the
longitudinal axes of the top and the bottom longitudinal axes
(arrows nested inside one another). If the first impingement drying
unit in this case is the foremost of the impingement drying units
in the transport path, the respective uneven (e.g. the third and/or
fifth) impingement drying unit again also extends in the same way
as the first; this means that the front sections of the first and
every other impingement drying unit point in the same direction in
relation to the respective longitudinal axis in each case. In a
preferred embodiment, the front section of all uneven impingement
drying units are arranged essentially on the same vertical level;
the same also applies preferably to the front sections of all even
impingement drying units.
[0011] The impingement surfaces of the impingement drying units
preferably run symmetrically to their respective longitudinal axis.
The impingement surfaces can be shaped to be level, but they can
also be curved, particularly in a convex curve. Furthermore, the
impingement surfaces can extend in parallel to the longitudinal
axis of the respective impingement drying unit; if the impingement
surface is curved, the tangent at the apex of the impingement
surface can run in parallel to the longitudinal axis in this case.
The impingement surfaces and their respective apex tangents extend
at an angle of less than 90.degree., advantageously less than
45.degree., preferably less than 30.degree., especially preferably
less than 15.degree., in relation to their respective longitudinal
axis.
[0012] It is particularly preferable if the impingement drying
device is arranged immediately after a press in the device because
the pulp web has a high water content immediately after passing
through the press so that impingement drying there can be utilized
to particularly good effect. The impingement drying device or an
additional impingement drying device, which is designed according
to the invention, is arranged accordingly immediately after a
coating head, which treats the paper with some kind of media, such
as size or impregnating material, so the paper therefore also has
higher wetness again.
[0013] In a preferable embodiment of the device according to the
invention, the respective impingement drying device is followed
immediately by drying cylinders arranged one behind the other in a
horizontal row (single-row design) or in two rows one above the
other, each arranged horizontally one behind the other (two-row
design).
[0014] On the supporting fabric side there may also be suction
devices, also combined suction/blow devices, in order to hold the
pulp web closely on the supporting fabric, where suction devices
and blow devices can be arranged alternately, for example, in the
suction/blow device in the pulp web longitudinal direction.
[0015] Moreover, the respective impingement drying unit can be
equipped with pulp web deflection rolls that have a perforated roll
shell and to which suction is applied. Suction through these rolls
can be applied either indirectly via a suction box or directly
through the roll shaft.
[0016] In the following, the invention is explained on the basis of
embodiment examples and referring to the figures. In the
drawing:
[0017] FIG. 1 shows a schematic side view of a device for producing
a pulp web according to an embodiment of the invention,
[0018] FIG. 2 shows a schematic side view of a device for producing
a pulp web according to another embodiment of the invention,
[0019] FIG. 3 shows a schematic side view of a device for producing
a pulp web according to yet another embodiment of the invention,
and
[0020] FIG. 4 shows a schematic side view of a device for producing
a pulp web according to yet another embodiment of the
invention.
[0021] The same reference numerals are used in the figures for the
same components.
[0022] In the device 1 according to the invention for producing a
pulp web 1, as shown in FIG. 1, the pulp web 3 is transported
essentially from left to right along a transport path (arrow Tw),
where the transport path, i.e. the progression or course of the
pulp web 3 in the device 1, as such runs partially in a meandering
course around rolls, and where the transport path also has sections
that run for a short stretch in the opposite direction to the
general transport path Tw. Moreover, the expressions "device in the
transport path at the front" and "device in the transport path at
the rear", for example, should also be understood to mean that the
pulp web 3 runs first of all through the front device in the
transport path and, in contrast, does not run through the rear
device in the transport path until later. The device has an
elongated design corresponding to the general transport path Tw,
where the longitudinal axis of the device VL extends essentially
horizontally.
[0023] The device 1 has an impingement drying device 5 located in
the transport path Tw, which in turn has: a first elongated
impingement drying unit 7 and a second elongated impingement drying
unit 9 adjacent to the first. Each of the impingement drying units
7, 9 has two impingement surfaces 11, 13 and 15, 17, respectively,
which are arranged on opposite sides of the longitudinal axis L of
the corresponding impingement drying unit 7, 9 and each of which
has its own supporting fabric 19, 21 that supports the pulp web 3
from one side only. The supporting fabric 19, 21 of the respective
impingement drying unit 7, 9 is guided over four respective
deflection rolls 23', 23, 25 and 27', 27, 29 in a rectangular shape
in each case, where this rectangle is formed by two triangles with
the same base side and whose apexes point in opposing direction
(kite shape).
[0024] Both impingement drying units 7, 9 have a front (end)
section 31 and 33, and a rear (end) section 35, 37, respectively,
viewed in their longitudinal direction L in each case, where the
front sections 31, 33 face one another and are mounted adjacent to
one another, respectively, and at approximately the same height,
which also corresponds approximately to the height of the
horizontal elongation or longitudinal elongation (longitudinal axis
VL) of the device 1. In the bottom impingement drying device shown
in FIG. 1, the device's deflection rolls 23 are arranged
symmetrically to their longitudinal axis L; i.e. the foremost
deflection roll 23' and the rearmost deflection roll 25 in relation
to the longitudinal axis L define the longitudinal axis L and the
two remaining deflection rolls 23 lie perpendicular to the
longitudinal axis L diametrically opposite one another. In the top
impingement drying unit 9 shown in FIG. 1, the foremost deflection
roll 27' is arranged such that it is offset by a certain distance
downwards towards the longitudinal axis L; the triangle formed by
the rearmost deflection roll 29 and the two middle deflection rolls
27 is arranged symmetrically to the longitudinal axis L of the top
impingement drying unit 9.
[0025] In this kite shape formed by deflection rolls 23', 23, 25
and 27', 27, 29, respectively, the supporting fabric 19 and 21 of
the first and second impingement drying unit 5, 7, respectively,
circulates in a largely convex shape, i.e. there are only convex
deflection points apart from the straight sections between the
deflection rolls 23', 23, 25, 27', 27, 29, and no concave
sections.
[0026] In addition, each of the impingement drying units 7, 9 has
an impingement dryer 39, 41 each with four bottom dryers 39', 39'',
39''', 39.sup.IV and 41', 41'', 41''', 41.sup.IV, respectively.
Here, one of the bottom dryers 39', 39'' and 41', 41'',
respectively, is each arranged directly opposite the side of each
impingement surface 11, 13 and 15, 17, respectively, facing away
from the respective supporting fabric 19 and 21, respectively,
where the bottom dryers have a hood inside which an impingement
medium (hot air) can be applied directly to the pulp web 3 in the
area of the impingement surface 11, 13, 15, 17.
[0027] On the side of each impingement surface 11, 13, 15, 17
facing the supporting fabric 19 and 21, respectively, one of the
bottom dryers 39''', 39.sup.IV, 41''', 41.sup.IV is mounted with a
hood inside which the impingement medium can be applied to the pulp
web 3 indirectly through the supporting fabric 19, 31 in the area
of the impingement surface 11, 13, 15, 17. If the supporting fabric
has a closed design here, e.g. in the form of a non-perforated
plastic belt or a non-perforated metal strip, the impingement
medium only effects heating of the supporting fabric 19, 31 so that
drying of the pulp web 3 is caused by heat conduction only. In a
preferred embodiment, the respective supporting fabric 19, 31 is
perforated so that the impingement medium can also act on the pulp
web 3 directly through the supporting fabric 19, 31 in places;
however this direct action in places should be understood as being
indirect through the supporting fabric within the context of the
invention.
[0028] The longitudinal axis L of the first impingement drying unit
7 and the longitudinal axis of the second impingement drying unit 9
are arranged essentially parallel to one another and at an angle of
inclination .alpha. of 35.degree.-55.degree., preferably
40.degree.-50.degree., more preferably approximately 45.degree., in
relation to a horizontal plane HE. The first and the second
impingement drying units, 7, 9 are arranged, as described above,
with their front sections 31, 33, viewed in their longitudinal
direction L, facing one another and adjacent to one another,
respectively, where they extend from their respective front section
31, 33 in their respective longitudinal direction in opposite
directions (both vertically and horizontally). In this case, the
bottom, first impingement drying unit 7 in FIG. 1, which is
arranged in the transport path Tw of the top, second impingement
drying unit 9, extends, beginning from its front section 31, in its
longitudinal direction L on a slant downwards in relation to the
horizontal plane HE and to the rear (in relation to the transport
path Tw). Accordingly, the second impingement drying unit 9 extends
in relation to the horizontal plane HE beginning from its front
section 33 on a slant upwards and forwards (in relation to the
transport path Tw).
[0029] The rear deflection roll 25 and 29, respectively, viewed in
longitudinal direction L of the respective impingement drying unit
7, 9, is designed as a suction roll, where suction can be applied
to the inside by means of an external suction box 25', 29'. Suction
can also be applied to the suction roll directly via a hollow
suction roll shaft. The respective supporting fabric 19 and 21,
respectively, of the first and second impingement drying unit 7 and
9, respectively, runs in a convex arrangement in the transport path
between the two respective impingement surfaces.
[0030] The device 1 also has a press section 43 with a split press
45, which contains two press rolls 49, 51 facing one another and
forming a press gap 47 in between. The damp pulp web 3 is guided
through the press gap 47 and the moisture is pressed out as a
result. Immediately after it the paper web 3 is guided to the first
impingement drying unit 7 of the impingement drying device 5. The
transfer point to and point of reception 53 at the first
impingement drying unit 7 are located in the unit's front section
31, right at the front deflection roll 23 which has a suction
device exactly at the transfer point 53 in order to hold the pulp
web 3 securely on the deflection roll 23 by suction.
[0031] The pulp web 3 runs successively through the impingement
surfaces of the first impingement drying unit 7 and reaches a
release point 55 of the first impingement drying unit 7 where the
pulp web 3 is carried away from the first impingement drying unit
7; this release point 55 is also located in the front section of
the first impingement drying unit 7.
[0032] The reception point 57 at which the pulp web 3 enters the
second impingement drying unit 9 lies immediately adjacent to the
release point 55 of the first impingement drying unit 7, in its
front section 33, formed in this case at the front deflection roll
27', which is fitted for this purpose with a suction device at the
reception point 57. The pulp web 3 then runs successively through
the impingement surfaces 17, 15 of the second impingement drying
unit 7, to then be transferred at a release point 59 also located
in the front section 33 of the second impingement drying unit 7, to
a drying section 61 of the device arranged immediately following
it.
[0033] In the section between the front deflection roll 27' and the
subsequent middle deflection roll 27 in web running direction a
suction device in the form of a suction box 63, 65 is arranged on
the side of the respective supporting fabric 19, 21 facing away
from the pulp web 3 with which suction is applied to the pulp web 3
in the direction of the supporting fabric 19 and 21, respectively,
assigned in each case in order to stabilize the passage of the
web.
[0034] The drying section 61 has a plurality of drying cylinders 67
arranged one behind the other in a single row in the horizontal
plane along the longitudinal axis VL, between which deflection
rolls 69 are arranged underneath in a row parallel to the row of
drying cylinders. The pulp web 3 is guided alternately in a
meandering path over the drying cylinders 67 and the deflection
rolls 69. The drying section 61 is divided, for example, into
several drying groups, where FIG. 1 only shows the drying group
located nearest to the impingement drying unit 5. Each drying group
comprises a number of drying cylinders. In the present case, the
drying group shown in FIG. 1 is fitted with a single supporting
fabric 71, which is brought close to the pulp web 3 from above,
where it supports the pulp web from the outside as it is wrapped
over the drying cylinder 67 so that the pulp web 3 rests directly
on the drying cylinder 67, and where the supporting fabric 71 lies
between the deflection rolls 69 and the pulp web 3 as the pulp web
3 is wrapped round the deflection rolls 69.
[0035] Groups with two rows of drying cylinders arranged parallel
to one another may also be mixed with single rows of drying
groups.
[0036] The impingement drying device according to the invention,
for example the impingement drying device 5 described above on the
basis of FIG. 1, is arranged in a preferred embodiment immediately
after the pressing unit 43 and immediately before the drying
section 61 of the device 1; however it can also be arranged between
drying groups of drying cylinders or also between drying cylinders
within drying groups. It would also be feasible in existing
devices, for example, to replace one or two drying groups with the
impingement drying device according to the invention, where further
drying groups could be omitted as a result because the drying
capacity of an impingement drying group is greater than that of a
number of drying cylinders. In a preferred embodiment, the
impingement drying device according to the invention or an
additional impingement drying device composed according to the
invention can also be arranged immediately following a coating
head, which is often positioned between drying groups in the drying
section.
[0037] In the embodiment shown in FIG. 2 of a device 1 according to
the invention for producing a pulp web 3, the impingement drying
device 5 also has a third and fourth impingement drying unit 73 and
75, respectively, in addition to the first and second impingement
drying units 7, 9.
[0038] The third impingement drying unit 73 is arranged immediately
adjacent to the second impingement drying unit 9; it has an
extended design, where its longitudinal axis L runs parallel to the
longitudinal axes L of the first and second impingement drying
units, 7, 9; it extends from a front (end) section 77, slanting
downwards and to the rear (in the direction of the transport path
Tw); its front section 77 lies on approximately the same height
level as the front sections 31, 33 of the first and the second
impingement drying units 7, 9.
[0039] The fourth impingement drying unit 75 is arranged in the
transport path immediately adjacent to the third impingement drying
unit 73; it has an extended design, where its longitudinal axis L
runs parallel to the longitudinal axes L of the first to the third
impingement drying units 7, 9, 73; it extends from a front (end)
section 79, slanting upwards and forwards (in the direction of the
transport path Tw); its front section 79 lies on approximately the
same height level as the front sections 31, 33, 77 of the first to
the third impingement drying units 7, 9, 73.
[0040] The third and the fourth impingement drying units 73, 75
have the same individual components as the first and second
impingement drying units 7, 9, which means that each have their own
supporting fabric 81, 83 that runs along a rectangular loop in a
kite shape defined by deflection rolls 85', 85, 87, and 89', 89,
91, respectively; in addition, they each have two impingement
surfaces 93, 95 and 97, 99, respectively, and one impingement dryer
101, 103 which acts both on the sides facing away from the
respective supporting fabric 81, 83 and on the sides of the
impingement surfaces 93, 95 and 97, 99, respectively, facing the
respective supporting fabric 81, 83 by having a respective hood
arranged there inside which an impingement medium is applied to the
respective side of the impingement surfaces 93, 95, 97, 99.
[0041] In its front section 77, the third impingement drying unit
73 has both a reception point 105 and a release point 107, at which
the pulp web 3 is transferred from the release point 59 of the
second impingement drying unit 9 directly to the third impingement
drying unit 73 and the pulp web 3 is transferred from the third
impingement drying unit 73 directly to the fourth impingement
drying unit 75, respectively, which is provided with a reception
point 109 for this purpose in its front section 79. In its front
section 79, the fourth impingement drying unit 75 also has a
release point 111 at which the pulp web 3 is transferred from the
fourth impingement drying unit 75 and thus from the impingement
drying unit 5 to the drying section 61 which follows.
[0042] The reception points 105 and 109 of the third and fourth
impingement drying units 73, 75, respectively, are also located
exactly at the front deflection rolls 85, 89, where these are
equipped with a suction device at the respective reception point
105, 109.
[0043] At all of the impingement drying units 7, 9, 73, 75 shown in
FIGS. 1 and 2, the impingement surfaces 11 and 13, 15 and 17, 93
and 95, 97 and 99, respectively, are arranged symmetrically to the
longitudinal axis of the respective impingement drying unit 7, 9,
73, 75; however it is possible to arrange the respective pair of
impingement surfaces 11 and 13, 15 and 17, 93 and 95, 97 and 99,
respectively, asymmetrically in relation to the respective
longitudinal axis L.
[0044] In FIGS. 1 and 2, the longitudinal axes L are defined as
running through the gap between the rear deflection roll 25, 29,
87, 91 and the middle of the space between the two middle
deflection rolls 23, 27, 85, 89; however the longitudinal axes
could also be defined as running between the respective front and
rear deflection rolls 23' and 25, 27 and 29, and between 85' and
87, 89' and 91, respectively; in the latter case, only impingement
surfaces 11, 13 would then be arranged symmetrically to the
respective longitudinal axis L in the first impingement drying
device 7, whereas impingement surfaces 15 and 17, 93 and 95, 97,
and 99, respectively, are then arranged asymmetrically to the
longitudinal axis L' there in the second to the fourth impingement
drying devices 9, 73, 75.
[0045] In the embodiment shown in FIG. 3 of a device 1 according to
the invention for producing a pulp web 3, the impingement drying
device 5 has a first and second impingement drying unit 7, 9, whose
longitudinal axes L run at an angle .alpha. of 45.degree. in
relation to the horizontal plane HE and which both slant from their
front (viewed in longitudinal direction) end sections 31 and 33,
respectively, to the rear in transport direction Tw so that their
longitudinal axes L extend at an angle of 90.degree. in relation to
one another (arrow pointing in the opposite direction to the
transport direction). In other words, the first and second
impingement drying units 7, 9 extend from their respective front
section 31 and 33, respectively, in their respective longitudinal
direction horizontally in the same direction (here to the rear) and
vertically in opposite directions (these being upwards and
downwards, respectively).
[0046] The first impingement drying unit 7 is arranged immediately
after a press section 43 and immediately before a drying section 61
in web running direction (pulp web path).
[0047] With regard to their structural details, the impingement
drying units 7, 9 are otherwise the same as the embodiments
described previously according to FIGS. 1 and 2, thus reference is
made in this respect to the preceding description.
[0048] In the embodiment shown in FIG. 4 of a device 1 according to
the invention, the impingement drying unit 5, which is also
arranged here between a press section 43 and a drying section 61,
has four impingement drying units 7, 9, 73, 75, which are designed
in their structural details according to the four impingement
drying units 7, 9, 73, 75 corresponding to the embodiment in FIG.
2. In this case, however, all the longitudinal axes L. of the
impingement drying units 7, 9, 73, 75 do not run parallel to one
another, only the longitudinal axes L of the two top impingement
drying units 9, 75 and the longitudinal axes L of the two bottom
impingement drying units 7, 73. Here, the longitudinal axes L of
the two top impingement drying units 9, 75 slant at an angle
.alpha.' of 55.degree. to the rear in transport direction Tw in
relation to the horizontal plane HE, and the longitudinal axes L of
the two bottom impingement drying units 7, 73 slant to the rear at
an angle .alpha. of 45.degree. in relation to the horizontal plane
HE. Thus, the longitudinal axes L of the two top impingement drying
units 9, 75 extend in relation to the longitudinal axes L of the
two bottom impingement drying units 7, 73 at an angle of
100.degree. in relation to one another (arrow for the longitudinal
axes L pointing in the opposite direction to the transport
direction Tw). In other words, the first, the second, the third,
and the fourth impingement drying units 7, 9, 73 and 75,
respectively, extend from their respective front sections 31, 33,
77 and 79 in their respective longitudinal direction horizontally
in the same direction (in this case downwards) and vertically in
opposite directions (with the bottom impingement drying units 7, 73
extending downwards and the top impingement drying units 9, 75
extending upwards).
[0049] In a preferred embodiment, the impingement drying unit 5 has
an even number of impingement drying units.
[0050] Further advantages of the invention are, for example, as
follows: as the front section seen in longitudinal direction of the
respective impingement drying unit is preferably designed as
tapering towards its longitudinal end, the impingement drying units
whose front sections face one another can be arranged closely
beside one another at the front. Also the rear section of the
respective impingement drying unit, viewed in longitudinal
direction, preferably has a tapered shape so that it can be
accommodated in a space-saving arrangement.
* * * * *