[0001] The present invention relates to a shoe press for a paper or board machine according
to the preamble to claim 1.
[0002] A shoe press with a device for displacing a press shoe relative to the centre line
of the shoe press, containing the centre line of the counter roll, is known from Fig.
6 in DE-A1-331 74 57 where the device comprises a pressure-fluid-actuatable tube and
a spring. Various other devices for displacing the centre of gravity of the supporting
force acting on the press shoe relative to the press shoe are disclosed in US-A-4,713,147,
in which a press shoe support between the press shoe and the frame system of the shoe
press is displaceable in the cross direction relative to the press shoe. In one variant,
the press shoe support is a pressure-fluid-actuatable loading cylinder for pressing
the press shoe towards the counter roll.
[0003] The above-mentioned possibilities of displacement serve to allow variation of the
press force or pressure profile on the paper or cardboard web in the nip between the
press shoe and the counter roll, said variation in turn aiming at being able to optimally
press different paper/cardboard qualities. For example, when pressing thin paper qualities
that are exposed to rewetting at the outlet end of the extended nip, a press force
pattern is required, which has its maximum close to said outlet end and, when pressing
cardboard qualities that are exposed to the risk of breaking if the press force pattern
is too pronounced, a relatively uniform press force pattern is required, which has
its press force maximum close to the centre of the extended nip.
[0004] The invention is based on said variant according to US-A-4,713,147 and its object
is to simplify and make the device for displacing the centre line of the loading cylinder
relative to the centre line of the press less expensive, and in particular to be able
to easily displace the centre line of a plurality of loading cylinders simultaneously.
[0005] The object is achieved by a shoe press of the type described by way of introduction
and having the features defined in claim 1. Advantageous embodiments have the features
stated in the dependent claims.
[0006] The invention will now be described in more detail with reference to the accompanying
drawings, in which
Fig. 1 is a cross-sectional view of a non-limiting embodiment of the invention in
the machine direction,
Fig. 2 is a cross-sectional view of another embodiment of the invention in the machine
direction, parts of the shoe press according to Fig. 1 being removed for better clarity,
and
Figs 3a, 3b and 3c are schematic top plan views of the second embodiment in a basic
position corresponding with the position in Fig. 3 and two other operating positions
in the cross direction.
[0007] Fig. 1 illustrates a shoe press for the press section of a paper or board machine,
said machine comprising the conventional shoe press components press shoe 1, counter
roll 2 having the direction of rotation R, which between them form an extended nip
N, in which a paper or cardboard web W, which is to be dewatered, runs together with
a circulated flexible press belt 3 and one or two press felts F, of which one is shown.
A horizontal beam 4 associated with the frame system 5 of the shoe press has, between
its side facing the press shoe and the opposite side of the press shoe, a number of
loading cylinders 6 which are arranged in a row or in several rows in the longitudinal
direction of the shoe press and have a cylinder and a piston. The cylinder consists
of two parts 7, 7' and a uniform piston 8 through which a duct 8' extends and mutually
connects two working chambers 8", 8"' of the loading cylinder, which can be considered
as a single working chamber if the duct 8' is very wide. The cylinder part 7 is fixed
to the upper side of the horizontal beam 4 by means of two sectional rails 9, 9' arranged
in the longitudinal direction of the press shoe 1 in diametrically opposed positions
of the cylinder part 7, and screws 10 extending through the rails 9, 9' and being
screwed into the beam 4, as illustrated. Analogously the cylinder part 7' is fixed
to the underside of the press shoe 1 by means of two sectional rails 11, 11' and screws
12 which are screwed into the press shoe 1, in this case, however, via an adapter
13. The sectional bars 9, 9'; 11, 11' engage with the cylinder parts 7, 7' in such
manner that the latter can be made to turn about a common centre axis C, secured against
displacement in the machine direction, i.e. the position of the axis C being fixed
within predetermined tolerance limits so that said turning of the cylinder parts 7,
7' is allowed without jamming. In the embodiment, flanges 14, 14' are arranged for
this purpose on the cylinder parts 7, 7' and guiding grooves 15a-15d are formed in
the sectional rails 9, 9'; 11, 11'.
[0008] The piston 8 is laterally sealed against the cylindrical inner surface of each cylinder
part 7, 7' by means of a sealing ring 16, 16'.
[0009] The cylinder parts 7, 7' are eccentrically formed in such manner that they have one
and the same outer radius counted from their common centre axis C, in relation to
which the common centre axis C1 of the internal cylinder surfaces of the cylinder
parts 7, 7' and, thus, of the outer surface of the piston 8 is displaced in parallel.
In this embodiment, the axis C extends in the centre line of the shoe press, in the
so-called press plane of the shoe press, in which also the centre axis of the counter
roll 2 extends. With a press shoe which is symmetrical relative to the press plane
(axis C), the press force has its maximum in the press plane if C=C1, seen in the
machine direction.
[0010] With a view to obtaining the regulation, mentioned by way of introduction, of the
press force pattern or the pressure profile on the paper or cardboard web in the extended
nip N between the press shoe 1 and the counter roll 2, the distance in the machine
direction between the axes C and C1 is according to the invention regulated by turning
the cylinder parts 7, 7' about their common centre axis C.
[0011] For the purpose of turning, the cylinders 7, 7' are in this embodiment each formed
with a circumferential toothing 17, 17' with vertical teeth which can be formed of
gear rims fixed to the cylinder parts 7, 7', and the toothings 17, 17' engage, along
the cylinder generatrix, with a toothing on a gear rack 18, 18' each, which can be
made to move in a translatory manner in its longitudinal direction, which corresponds
with the longitudinal direction of the press shoe, i.e. the cross direction, during
turning of the cylinder parts 7, 7'. The sectional rails 9, 9'; 11, 11' have for this
purpose guiding grooves 19, 19' for the gear racks 18, 18', said guiding grooves holding
the gear racks in such manner that they can only move in their longitudinal direction
when being operated.
[0012] The gear racks 18, 18' are operable, for said turning of the cylinder part, from
a position outside the shoe press, so that the press force or pressure profile of
the shoe press (determined by the distance in the machine direction C-C1) can be changed
or controlled when necessary, without the belt 3 of the shoe press having to be dismounted.
[0013] Of course, the gear racks 18, 18' are to be operated in unison. The gear racks 18,
18' can therefore be mutually fixedly interconnected outside the one end wall or both
end walls of the shoe press, where the operating means for displacement of the gear
racks are arranged. A person skilled in the art can easily find constructions of the
operating means in his normal source of knowledge, for instance a crank mechanism
or a hydraulic jack, which is allowed to press or pull the ends of the gear racks
18, 18' positioned outside said end wall/end walls, thereby effecting turning of the
cylinder parts 7, 7' in unison in one or the other turning direction as the relative
displacement C-C1 is to involve becoming mutually closer or more remote. The two gear
racks 18, 18' can also be combined to.a single, broader gear rack.
[0014] An arbitrary suitable operating means adjacent to the two end walls G of the shoe
press is designated A in Fig. 3.
[0015] It goes without saying that the loading cylinders 9 are supplied with pressure fluid
for pressing the press shoe towards the counter cylinder 2 for treating the paper/cardboard
web W in the extended nip of the shoe press. To this end, there is a pressure fluid
duct 20, extending from a source (not shown) via duct branches 20' and apertures 21
formed in the end wall of the cylinder part 7' to the working chambers 8", 8''' of
the loading cylinders 6. The duct 20 and the branches 20' are here formed in the adapter
13 (which serves merely to facilitate the making of the duct 20 and the branches 20';
it should be possible to form these directly in the shown press shoe 1), and a sealing
ring 22 is arranged to seal between the adapter and the opposing surface of the cylinder
7'.
[0016] The Figures also illustrate components which are not necessary for the understanding
of the invention: a lubrication bore relief 30 which is formed in the surface of the
press shoe 1 facing the counter cylinder 2 and to which lubricating fluid is supplied
from a source (not shown), via a pipe 31 which is fixed to the inlet side of the press
shoe and has holes 32 in its wall, and a duct 33 formed in the press shoe 1, the pipe
31 being able to supply a plurality of lubrication bore reliefs 30 spaced apart in
the longitudinal direction of the press shoe 1, via a corresponding number of ducts
33 and holes 32. The pipe 31 and a rounded portion 34 on the outlet side of the press
shoe 1 as well as opposite supports 35, 36 form guide means for the press shoe. An
abutment for the stroke of the piston 8 is designated 37.
[0017] The two-piece cylinder 7, 7' is advantageous by allowing the piston 8 to be floatingly
supported and freely movable in all directions in the cylinder parts 7, 7'. However,
the invention is, of course, also applicable to a loading cylinder which is formed
in one piece, corresponding to the cylinder part 7', like the piston, and which rests
against the beam 4, the working chamber of the loading cylinder 6 being supplied with
pressure fluid through a duct in the beam 4 and a duct in the piston. The invention
is also applicable to a loading cylinder with a two-piece piston and a cylinder, the
two pistons defining between them the common working chamber of the loading cylinder,
said working chamber being supplied with pressure fluid through a duct in the beam
or the press shoe and a duct in each piston part. On the whole, the invention is applicable
in cases where there is a detachable or movable connection between the loading cylinder
and the press shoe.
[0018] A second embodiment of the invention is shown in Fig. 2, in which merely the inventive
principle is illustrated in more detail. The same reference numerals in Figs 1 and
2 designate equivalent components. In this second embodiment, the cylinder parts 7,
7' of the cylinder, which is here also made in two pieces, have the same inner and
outer diameter and an eccentricity C-C1 is obtained by mounting the cylinder parts
7, 7' to be turned about an axis C in the centre line of the shoe press in the press
plane which is parallel with, but spaced from the common centre axis C1 of the cylinder
parts 7, 7'. The mounting is effected by means of pivot pins 40, 40' which extend
through the end wall of the cylinder parts 7, 7' and are attached by screwing to the
press shoe 1 and the beam 4, respectively. The pin 40 which is attached to the press
shoe 1 also acts as an inlet opening, corresponding to the hole 32 in Fig. 1, for
pressure fluid to the working chamber 8' of the loading cylinder.
[0019] For turning of the cylinder parts 7, 7', turning arms 41, 41' are fixed to the cylinder
parts 7, 7' and are at their free end articulated each to an operating rod 42, 42'.
The articulated joint is shown at 43. It will now be appreciated that when pressing
or pulling the operating rods 42, 42', the cylinder parts 7, 7' are turned about the
axis C, whereby the common centre axis C1 of the cylinder parts is displaced relative
to the axis C and the press force pattern or pressure profile in the extended nip
N changes.
[0020] Figs 3a-3c are schematic top plan views of loading cylinders 7, 7' and illustrate
schematically the turning in unison of three loading cylinders 6 (7, 7') from a basic
state (C=C1 in the machine direction) in Fig. 3a, corresponding with Fig. 2, to two
other operating states. Fig. 3b illustrates pushing of the operating rods 42 (42')
for turning of the loading cylinders 6 (7, 7') in counterclockwise direction from
the basic state, and Fig. 3c shows pulling of the operating rods 42, 42' for turning
of the loading cylinders 6 (7, 7') in clockwise direction from the state in Fig. 3a
or 3b.
[0021] The dashed line Ca represents the press plane containing the axis of rotation C of
the loading cylinders and the dashed line Cb represents the eccentricity. The dashed
lines Cc and Cd represent planes containing C1, where the maximum press force is obtained
at a distance from the press plane on, for instance, the outlet side of the shoe press
or on the inlet side thereof. If desired, the possibility of varying the press force
can be limited to one side only of the press plane.
[0022] It will be appreciated that the load pressure from the loading cylinders on the press
shoe is to be neutralised or reduced while the turning operation as described above
proceeds.
[0023] The inventive principle is also applicable to shoe presses in an inverted position
compared with Figs 1 and 2, i.e. shoe presses where the counter roll 2 is positioned
at the bottom and the press shoe 1 and the loading cylinders 6 at the top.
[0024] The term shoe press should in this description be understood to comprise also a shoe
press for calendering.
[0025] It goes without saying that the invention is also applicable to a shoe press with
a single loading cylinder.
1. A shoe press for a paper or board machine, comprising a press shoe (1) and a counter
roll (2), which between them form an extended nip (N) for a paper or cardboard web
and a circulated flexible belt (3), at least one loading cylinder (6) which is arranged
between a horizontal beam (4) included in the frame system (4, 5) of the shoe press,
and the press shoe (1) and adapted to press the press shoe (1) in the direction of
the counter roll (2), characterised in that the cylinder (7) or piston (8) of the loading cylinder is turnably mounted about
an axis (C), in relation to which the axis (C1) which forms an axis of symmetry for
the working chamber (8') of the loading cylinder is eccentric, and that the shoe press
has operating means (18, 18'; 42, 42', A) for turning the cylinder or piston of the
loading cylinder for controlling the pressure profile of the shoe press, said operating
means comprising an actuating member (A) extending outside the belt (3).
2. A shoe press as claimed in claim 1, characterised in that the cylinder (7, 7') of the loading cylinder (6) has a casing wall of non-uniform
thickness.
3. A shoe press as claimed in claim 1, characterised in that the cylinder (7, 7') of the loading cylinder (6) has a uniform wall thickness and
.eccentrically mounted for turning relative to the axis of symmetry (C1) of the working
chamber (8).
4. A shoe press as claimed in any one of claims 1-3, characterised in that the cylinder (7, 7') of the loading cylinder (6) has an external toothing (17, 17')
which extends along the circumference and with which a gear rack (18, 18') engages,
which is connected to the operating means (A).
5. A shoe press as claimed in any one of claims 1-4, characterised in that the cylinder (7, 7') of the loading cylinder (6) is connected to an arm (41, 41')
which in turn is connected to the actuating member (A).
6. A shoe press as claimed in claim 5, in which a plurality of loading cylinders (6)
are arranged, characterised in that the arms (41, 41') are articulated to a rod (42, 42') which in turn is connected
to the actuating member (A).
1. Schuhpresse für eine Papiermaschine oder Kartonmaschine mit einem Pressschuh (1) und
einer Gegenwalze (2), die zwischen sich einen Langspalt (N) für eine Papierbahn oder
Kartonbahn und einen umlaufenden flexiblen Riemen (3) ausbilden, und zumindest einem
Belastungszylinder (6), der zwischen einem horizontalen Balken (4), der bei dem Rahmensystem
(4, 5) der Schuhpresse umfasst ist, und dem Pressschuh (1) angeordnet ist und daran
angepasst ist, dass er den Pressschuh (1) in der Richtung der Gegenwalze (2) presst,
dadurch gekennzeichnet, dass
der Zylinder (7) oder der Kolben (8) des Belastungszylinders um eine Achse (C)
drehbar montiert ist, wobei in Bezug zu dieser die Achse (C1), die eine Symmetrieachse
für die Arbeitskammer (8') des Belastungszylinders ausbildet, exzentrisch ist, und
die Schuhpresse eine Betätigungseinrichtung (18, 18'; 42, 42', A) für ein Drehen
des Zylinders oder Kolbens von dem Belastungszylinder hat, um das Druckprofil zu steuern,
wobei die Betätigungseinrichtung ein Betätigungselement (A) aufweist, das sich außerhalb
des Riemens (3) erstreckt.
2. Schuhpresse gemäß Anspruch 1,
dadurch gekennzeichnet, dass
der Zylinder (7, 7') des Belastungszylinders (6) eine Gehäusewand mit ungleichförmiger
Dicke hat.
3. Schuhpresse gemäß Anspruch 1,
dadurch gekennzeichnet, dass
der Zylinder (7, 7') des Belastungszylinders (6) eine gleichmäßige Wanddicke hat
und exzentrisch montiert ist, um in Bezug auf die Symmetrieachse (C1) der Arbeitskammer
(8) zu drehen.
4. Schuhpresse gemäß einem der Ansprüche 1-3,
dadurch gekennzeichnet, dass
der Zylinder (7,7') des Belastungszylinders (6) eine Außenverzahnung (17,17') hat,
die sich entlang des Umfangs erstreckt und mit der eine Zahnstange (18,18') in Eingriff
steht, die mit der Betätigungseinrichtung (A) verbunden ist.
5. Schuhpresse gemäß einem der Ansprüche 1-4,
dadurch gekennzeichnet, dass
der Zylinder (7,7') des Belastungszylinders (6) mit einem Arm (41,41') verbunden
ist, der wiederum mit dem Betätigungselement (A) verbunden ist.
6. Schuhpresse gemäß Anspruch 5, bei der eine Vielzahl an Belastungszylindern (6) angeordnet
ist,
dadurch gekennzeichnet, dass
die Arme (41, 41') an einer Stange (42, 42') angelenkt sind, die wiederum mit dem
Betätigungselement (A) verbunden ist.
1. Presse à sabot pour une machine de fabrication de papier ou de carton, comprenant
un sabot de presse (1) et un contre-rouleau (2) qui entre eux forment une emprise
étendue (N) pour une bande continue de papier ou de carton et une courroie souple
en circulation (3), au moins un cylindre de chargement (6) qui est disposé entre une
poutre horizontale (4) incorporée dans le système de châssis (4, 5) de la presse à
sabot, et le sabot de presse (1), et apte à comprimer le sabot de presse (1) dans
la direction du contre-rouleau (2), caractérisée en ce que le cylindre (7) ou piston (8) du cylindre de chargement est monté de façon rotative
autour d'un axe (C), par rapport auquel l'axe (C1) qui forme un axe de symétrie pour
la chambre de travail (8') du cylindre de chargement est excentrique et en ce que la presse à sabot comporte des moyens opérationnels (18, 18' ; 42, 42', A) pour faire
tourner le cylindre ou le piston du cylindre de chargement pour commander le profil
de pression de la presse à sabot, lesdits moyens opérants comprenant un élément d'actionnement
(A) s'étendant à l'extérieur de la courroie (3).
2. Presse à sabot selon la revendication 1, caractérisée en ce que le cylindre (7, 7') du cylindre de chargement (6) présente une paroi de logement
d'épaisseur non uniforme.
3. Presse à sabot selon la revendication 1, caractérisée en ce que le cylindre (7, 7') du cylindre de chargement (6) présente une épaisseur de paroi
uniforme et est monté de façon excentrique pour la rotation par rapport à l'axe de
symétrie (C1) de la chambre de travail (8).
4. Presse à sabot selon l'une quelconque des revendications 1 à 3, caractérisée en ce que le cylindre (7, 7') du cylindre de chargement (6) comporte une denture extérieure
(17, 17') qui s'étend le long de la circonférence et avec laquelle une crémaillère
(18, 18') est en prise, laquelle est raccordée aux moyens opérants (A).
5. Presse à sabot selon l'une quelconque des revendications 1 à 4, caractérisée en ce que le cylindre (7, 7') du cylindre de chargement (6) est raccordé à un bras (41, 41')
qui à son tour est raccordé à l'élément d'actionnement (A).
6. Presse à sabot selon la revendication 5, dans laquelle sont disposés plusieurs cylindres
de chargement (6), caractérisée en ce que les bras (41, 41') sont articulés sur une tige (42, 42') qui à son tour est raccordée
à l'élément d'actionnement (A).