EP1314815A1 - Device for cleaning a screen cloth in a papermaking machine - Google Patents

Abstract

The assembly to clean at least one fourdrinier (1), at a papermaking machine, has rollers (11c) to guide the fourdrinier past at least one vacuum chamber (51,52) and at least one spray jet (57). The jet sprays the fourdrinier with a cleaning fluid, and especially water. The vacuum chamber lies radially outside the roller so that the fourdrinier, at the vacuum chamber, lies against the roller for most of its length. The vacuum chamber is sealed against the fourdrinier by lateral sealing bars (53-55).

Description

The subject invention relates to a device for cleaning the at least one screen belt in a paper production plant, in which the sieve belt is guided over rollers with at least one the sieve belt adjacent vacuum chamber and at least one in the vacuum chamber arranged spray nozzle, through which a Cleaning liquid, especially water, can be applied.

In paper production plants, a fiber suspension becomes one in itself closed sieve belt applied over rollers applied. They are too Systems known in which two screen belts are provided between which the paper tape is made. This applies to all systems Requirement that at least one screen belt in an area in which it is lifted from the paper tape and returned to the beginning of the system of components remaining in or on it, in particular cellulose fibers, to clean and dry.

From US no. 6,099,691 A is a device for cleaning the sieve belt a plant for paper production known, which consists of four vacuum chambers consists of two on each side of a screen belt are arranged and in which there are spray nozzles through which water is sprayed onto both surfaces of the belt, causing this is cleaned. The water applied through the spray nozzles becomes fed to a separator from the vacuum chambers. In addition, it will Air belt in one of the vacuum chambers to dry it.

Da an beiden Seiten des Siebbandes Vakuumkammern vorgesehen sind, wird durch diese Vorrichtung ein sehr großer Platzbedarf bedingt. Da das Siebband zwischen mindestens zwei Vakuumkammern hindurchgeführt wird, wobei es mit den Kanten von deren Eintritts- und Austrittschlitzen in Berührung kommt, besteht weiters die Gefahr, daß es durch die Bewegung über diese Kanten beschädigt wird. Zudem besteht das Erfordernis, die auf beiden Seiten des Siebbandes angeordneten Vakuumkammern an gesonderte Vakuumquellen anzuschließen und zudem diesen jeweils Wasserabscheider zuzuordnen. Weiters tritt das durch die Spritzdüsen auf das Siebband aufgebrachte Wasser durch dieses hindurch, wobei es die Verunreinigungen mitfördert. Da sich jedoch der überwiegende Anteil der Verunreinigungen auf derjenigen Seite des Siebbandes befindet, an welche das Papierband anliegt, bedingt dies, daß durch das auf diese Seite des Siebbandes aufgebrachte Wasser die Verunreinigungen durch das Siebband hindurch in die auf der anderen Seite des Siebbandes angeordnete Vakuumkammer gefördert werden. Hierdurch weist diese Reinigungsvorrichtung einen sehr schlechten Wirkungsgrad auf bzw. ist sie im Betrieb relativ teuer.

However, such known devices for cleaning a screen belt have several disadvantages:

Since vacuum chambers are provided on both sides of the sieve belt, this device requires a very large amount of space. Since the sieve belt is passed between at least two vacuum chambers, where it comes into contact with the edges of their inlet and outlet slots, there is also the risk that it will be damaged by the movement over these edges. In addition, there is a need to connect the vacuum chambers arranged on both sides of the sieve belt to separate vacuum sources and also to assign water separators to them. Furthermore, the water applied to the screen belt through the spray nozzles passes through it, thereby conveying the impurities. However, since the major part of the contaminants is on the side of the sieve belt to which the paper belt lies, this means that the water applied to this side of the sieve belt causes the contaminants to pass through the sieve belt into the vacuum chamber arranged on the other side of the sieve belt be promoted. As a result, this cleaning device has a very poor efficiency or is relatively expensive to operate.

The object of the invention is therefore a device for cleaning the at least one sieve belt in a system for To create paper, through which the known state of the art Disadvantages inherent in technology can be avoided. This is according to the invention achieved in that the at least one vacuum chamber radially outside one of the rollers over which the screen belt goes to the beginning of the system is returned, is arranged, which is in the effective range sieve belt located in this vacuum chamber at least over a large part its length lies against this roller.

There is thus at least one vacuum chamber only on that side of the sieve belt provided on which side the paper tape came to rest and where most of the impurities are. By the at least one spray nozzle located in this vacuum chamber the cleaning liquid is sprayed onto the sieve belt against the roller, which emerges from the sieve belt again on this side, whereby it contributes to the contamination. By reducing the number of provided vacuum chambers and the vacuum sources assigned to them significant constructive simplification is achieved, although the effectiveness of cleaning is increased. In addition, the Operating costs significantly reduced. Since the sieve belt in the area the at least one vacuum chamber is guided over a roller, is Trajectory set, causing the side edges of the vacuum chambers opposite to that side of the screen belt to which the paper belt comes to the plant, are at a defined distance. hereby any damage to the filter belt is caused by the edges of the inlet and exit openings of the at least one vacuum chamber excluded.

The at least one vacuum chamber is preferably opposite the one above the roller-guided screen belt by means of transverse to the direction of movement of the screen belt aligned sealing strips sealed. Furthermore lies preferably the sieve belt located in the area of the first vacuum chamber over the length of this vacuum chamber to the roller. It is also preferred the angle of the beam direction of the at least one in the first vacuum chamber spray nozzle arranged on a spray tube in the direction of movement of the sieve belt adjustable.

According to a preferred embodiment is in radially outside of the roller Direction of movement of the sieve belt next to the at least one vacuum chamber at least one second vacuum chamber is provided. It can the sieve belt located in the area of the first vacuum chamber its entire length against the roller and can be effective Area of the at least one second vacuum chamber area of the sieve belt rest against the roller over part of its length and over another part of its length be lifted off the roller.

Preferably, the at least one first vacuum chamber and the at least one second vacuum chamber are connected to a common vacuum source via a suction channel, furthermore control devices are arranged between the at least one first vacuum chamber and the at least one second vacuum chamber and the vacuum source, which are designed as flaps, for example can be pivoted about axes oriented approximately at right angles, and at least part of the at least one second vacuum chamber is designed with a cross section that increases transversely to the direction of movement of the sieve belt.
The at least one second vacuum chamber is preferably designed with a height that increases transversely to the direction of movement of the sieve belt, if at least some of the edges of the walls of the vacuum chambers assigned to the sieve belt and oriented transversely to its direction of movement are sealed with respect to the sieve belt by means of sealing strips, the sealing strips are attached to them the edges of the walls of the vacuum chambers associated with preferably T-shaped grooves, by means of which they are pushed onto the edges of the side walls of the vacuum chambers, and at least part of the sealing strips is asymmetrical.
Finally, the spray tube is preferably designed with needle jet nozzles and with flat jet nozzles.

Fig.1

eine Anlage zur Papiererzeugung, in schematischer Darstellung;

Fig.2

eine erfindungsgemäße Vorrichtung, in einem in Bewegungsrichtung des Siebbandes geführten vertikalen Schnitt;

Fig.3

diese Vorrichtung, im Schnitt nach der Linie III-III der Fig.2;

Fig.4

diese Vorrichtung, im Schnitt nach der Linie IV-IV der Fig.2 in gegenüber Fig.2 verkleinertem Maßstab;

Fig.5

das Detail A der Fig.2, in gegenüber Fig. 2 vergrößertem Maßstab;

Fig.6

das Detail B der Fig.2, in gegenüber Fig.2 vergrößertem Maßstab;

Fig.6a

das Detail B in einer Ausführungsvariante, in gegenüber Fig.2 vergrößertem Maßstab; und

Fig.7, 7a, 7b

einen Bestandteil dieser Vorrichtung, in Seitenansicht, in Draufsicht und im Schnitt.

The object of the invention is explained below with reference to an embodiment shown in the drawing. Show it:

Fig.1

a plant for paper production, in a schematic representation;

Fig.2

a device according to the invention, in a vertical section made in the direction of movement of the screen belt;

Figure 3

this device, in section along the line III-III of Figure 2;

Figure 4

this device, in section along the line IV-IV of Figure 2 on a reduced scale compared to Figure 2;

Figure 5

the detail A of Figure 2, on an enlarged scale compared to Figure 2;

Figure 6

the detail B of Figure 2, on an enlarged scale compared to Figure 2;

6a

detail B in an embodiment variant, on an enlarged scale compared to FIG. 2; and

Fig. 7, 7a, 7b

a part of this device, in side view, in plan view and in section.

1 shows a plant for paper production according to the invention, which has a first screen belt 1 and a second screen belt 2. These two sieve belts 1 and 2, which are closed in themselves, are moved over a plurality of guide or deflecting rollers 11 and 21 assigned to them at the same speed of, for example, about 40 m / sec, in the region of the rollers 11a and 21a are guided to one another and are separated from one another in the region of the rollers 11b and 21b. In the area in which the two sieve belts 1 and 2 are moved adjacent to one another there are a spray nozzle 3. Furthermore, a plurality of suction boxes 4 are provided on both sides of the sieve belts 1 and 2. In addition, a further spray nozzle 3a and a suction box 4a are arranged in the further course of the first screen belt 1. Finally, cleaning devices 5 for the two screen belts 1 and 2 are arranged in the region of the guide rollers 11c and 21c.
The first screen belt 1 and the second screen belt 2 can be assigned further cleaning devices of this type.

In the operation of this plant 1, in the area of the two rollers 11a and 21a in the direction of arrow C between the two sieve belts 1 and 2, the pulp pulp prepared for the production of a paper belt is introduced uniformly over the width of the two sieve belts 1 and 2. The liquid contained in the pulp is sucked off through the suction boxes 4 provided in the course of the two sieve belts 1 and 2, whereby a paper belt 6 is formed, which remains after the second sieve belt 2 has been lifted off the first sieve belt 1, whereby it passes through the further suction box 4a is further dried. Finally, it is lifted off the first screen belt 1 in the region of a deflecting roller 16 and is fed for further processing.
The spray nozzles 3 and 3a serve to moisten the sieve belts 1 and 2 when there is no pulp on them.

Since the two sieve belts 1 and 2 of cellulose fibers adhering to them etc.. need to be cleaned are in their other trajectories the cleaning devices 5 are provided, which are explained below are:

As can be seen from Figure 2, are located radially outside the guide roller 11c and on that side of the sieve belt 1 to which the Paper web 6 is applied, one after the other in the direction of movement of the belt 1 two vacuum chambers 51 and 52, the suction openings opposite the sieve belt 1 sealed by means of sealing strips 53, 54 and 55 are. Inside the first vacuum chamber 51 there is a nozzle 57 formed spray tube 56, via which on the associated side of the Sieve belt 1 water is sprayable. The vacuum chambers 51 and 52 are also assigned control flaps 62 and 63.

As can also be seen from FIG. 3, the two vacuum chambers are attached 51 and 52 connected to a common suction channel 61, which leads to a Water separator and leads to a vacuum source. At the connection of the Suction channel 5 to the two vacuum chambers 51 and 52 are the Control flaps 62 and 63, the control flap 62 about the axis 62a and Control flap 63 can be pivoted about axis 63a perpendicular to axis 62a are. The control flaps 62 and 63 can do this in the chambers 51 and 52 prevailing vacuum can be controlled. Like this too is indicated by a double arrow D, the spray tube 56 is oscillating can be pushed back and forth, the amplitude of the oscillatory movement approximately the distance of the spray nozzles 57 provided in the spray tube 56 from one another is equal to.

As can also be seen from FIG. 4, the second vacuum chamber 52 formed with a sloping bottom 52a. This ensures that the suction effect of the second vacuum chamber 52 over the Width of the belt 1 is approximately the same size.

As shown in Figure 5, the filter belt 1 is in the suction area of the first Vacuum chamber 51 over its entire length to the roller 11c. There Furthermore, the spray tube 56 can be rotated about its longitudinal axis Direction of the water jets emerging from this over the angular range of about α = 30 ° in the direction of movement of the sieve belt 1 become.

As can also be seen from FIGS. 5, 6 and 6a, the upper edges are the side walls of the vacuum chambers 51 and 52 are T-shaped formed and the sealing strips 53, 54 and 55 are profiled with opposite profiles Grooves formed. As a result, the sealing strips 53, 54 and 55 on the upper edges of the side walls of the vacuum chambers 51 and 52 be postponed. To the width of the effective area of the second To be able to adjust the vacuum chamber 52, the sealing strip 55 is opposite their groove is asymmetrical. Depending on the position of the Sealing strip 55 can be pushed onto the associated side wall the effective width of the effective range of the belt 1 second vacuum chamber 52 can be set with the values s and sl.

As shown in FIGS. 7, 7a and 7b, is according to a further embodiment the spray tube 56a with a first group of needle jet nozzles 57a and a second group of flat jet nozzles 57b, which are mutually offset in the longitudinal direction of the spray tube 56a and the rays of which enclose an acute angle of approximately 10 ° with one another. Furthermore, the levels of the jets of the flat jet nozzles close 57b with the plane formed by the jets of the needle jet nozzles 57a an angle of about 5 °.

Das Siebband 1, welches als in sich geschlossenes Band ausgebildet ist, ist über die Führungs- und Umlenkwalzen 11, 11a, 11b und 11c gelegt, wobei es an diese Walzen mit derjenigen Seite anliegt, welche nicht an das Papierband 6 zur Anlage kommt. Die der Walze 11c zugeordnete Reinigungsvorrichtung 5 weist zwei in Bewegungsrichtung des Siebbandes 1 aufeinanderfolgenden Vakuumkammern 51 und 52 auf. Im Wirkungsbereich der ersten Vakuumkammer 51 liegt das Siebband 1 vollständig an die Walze 11c an, wobei sich die Vakuumkammer 51 an derjenigen Seite befindet, mit welcher das Siebband 1 an die Papierbahn 6 angelegen ist. Es ist dies demnach diejenige Seite, an welcher sich der überwiegende Teil der Papierfasern u.dgl. befindet. Die Vakuumkammer 51 ist gegenüber dem Siebband 1 mittels der Dichtungsleisten 53 und 54 abgedichtet. Da das Siebband 1 durch die Walze 11c geführt ist, ist gewährleistet, daß es an den Dichtungsleisten 53 und 54 nicht schleift. Dies ist deshalb maßgeblich, da das Siebband 1 gegenüber mechanischen Beschädigungen sehr empfindlich ist.

The mode of operation of the cleaning device 5 is explained below using the first screen belt 1:

The screen belt 1, which is designed as a self-contained belt, is placed over the guide and deflecting rollers 11, 11a, 11b and 11c, it being against these rollers with the side that does not come into contact with the paper belt 6. The cleaning device 5 assigned to the roller 11c has two vacuum chambers 51 and 52 which follow one another in the direction of movement of the screen belt 1. In the effective range of the first vacuum chamber 51, the screen belt 1 lies completely against the roller 11c, the vacuum chamber 51 being on the side with which the screen belt 1 is placed against the paper web 6. It is therefore the side on which the majority of the paper fibers and the like. located. The vacuum chamber 51 is sealed off from the sieve belt 1 by means of the sealing strips 53 and 54. Since the sieve belt 1 is guided through the roller 11c, it is ensured that it does not rub against the sealing strips 53 and 54. This is important because the sieve belt 1 is very sensitive to mechanical damage.

By means of the spray tube 56 located in the vacuum chamber 51 is on this side of the sieve belt 1 is a cleaning liquid, in particular water, sprayed, which however does not pass through the sieve belt 1, but from this also due to the centrifugal force caused by the deflection of the occurs at high speed moving belt 1, on the same side emerges again and via the vacuum chamber 51 and the suction line 61 is discharged. Because the cleaning liquid on the one Side on which the impurities are located, very good efficiency is achieved. To achieve an optimal Cleaning effect can be the direction of the rays of the cleaning liquid with respect to the direction of movement of the sieve belt 1 in the range of the angle α can be set. In addition, the spray tube 56 performs an oscillating adjustment transversely to the direction of movement of the belt 1, whereby Sieve belt 1 is covered over its entire width by the cleaning liquid becomes. The cleaning liquid removes dirt from the sieve belt 1 removed. As a result, the screen belt 1 reaches the area of the second Vacuum chamber 52, which is placed between the sealing strips 54 and 55 comes into effect. In this area, the sieve belt 1 is only in a first part to the roller 11c, whereas in the second part of the Roller 11c is lifted off. In this area, on the one hand, this is in the sieve belt 1 water is sucked out and on the other hand becomes air from the outside sucked in, whereby the filter belt 1 is dried.

The action of the vacuum chambers 51 and 52 is controlled by means of the control flaps 62 and 63 controlled. Since the second vacuum chamber 52 with one in Suction direction widening cross-section is formed across the width the sieve belt 1 achieves a constant suction effect.

Through the needle jet nozzles 57a in the first vacuum chamber 51 Surface of the sieve belt 1 cleaned, where deposited and dried Dirt particles are removed. Through the flat jet nozzles 57b the cavities of the filter belt 1 are filled with water. In the second Vacuum chamber 52 becomes this water and with it the fine particles sucked out of the sieve belt 1.

A device is thus created which is compared to known cleaning devices has a simplified constructive training, making it cheaper to manufacture and taking up less space, which are more effective and economical as well as in operation is cheaper and with which damage to the sieve belt, which opposite Damage is very sensitive, to be avoided as far as possible.

Claims (15)

Device for cleaning the at least one screen belt (1) in a plant for paper production, in which the screen belt (1) is guided over rollers (11), with at least one vacuum chamber (51, 52) resting on the screen belt (1) and at least one in this arranged spray nozzle (57), through which a cleaning liquid, in particular water, can be applied to the sieve belt (1), characterized in that the at least one vacuum chamber (51, 52) is arranged radially outside one of the rollers (11c), wherein the sieve belt (1) located in the area of the vacuum chamber (51, 52) lies against this roller (11c) at least over a large part of its length (FIG. 2). Device according to claim 1, characterized in that the at least one vacuum chamber (51, 52) seals against the sieve belt (1) guided over the roller (11c) by means of sealing strips (53, 54, 55) oriented transversely to the direction of movement of the sieve belt (1) is. Device according to one of claims 1 and 2, characterized in that the screen belt (1) located in the area of the first vacuum chamber (51) bears against the roller (11c) over the entire length of this vacuum chamber (51). Device according to one of Claims 1 to 3, characterized in that the angle of the jet direction of the at least one spray nozzle (57) located in the first vacuum chamber (51) on a spray tube (56) is adjustable in the direction of movement of the sieve belt (1). Device according to one of claims 1 to 4, characterized in that at least one second vacuum chamber (52) is provided radially outside the roller (11c) in the direction of movement of the screen belt (1) in addition to the at least one first vacuum chamber (51). Device according to claim 5, characterized in that the screen belt (1) located in the area of the first vacuum chamber (51) bears against the roller (11c) over its entire length and in that the area in the effective area of the at least one second vacuum chamber (52) located area of the screen belt (1) abuts the roller (11c) over part of its length and is lifted off the roller (11c) over another part of its length. Device according to one of the claims 5 and 6, characterized in that the at least one first vacuum chamber (51) and the at least one second vacuum chamber (52) are connected to a common vacuum source via a suction channel (61). Device according to claim 7, characterized in that control devices are arranged between the at least one first vacuum chamber (51) and the at least one second vacuum chamber (52) and the vacuum source. Device according to claim 8, characterized in that the control devices are designed as flaps (62, 63) which can be pivoted about axes oriented approximately at right angles. Device according to one of Claims 1 to 9, characterized in that at least some of the vacuum chambers (51, 52) are designed with a cross section which increases transversely to the direction of movement of the sieve belt (1). Apparatus according to claim 10, characterized in that the at least one second vacuum chamber (52) is formed with a height which increases transversely to the direction of movement of the sieve belt (1). Device according to one of the claims 1 to 11, characterized in that at least a part of the edges of the vacuum chambers (51, 52) assigned to the sieve belt (1) and oriented transversely to its direction of movement seals against the sieve belt by means of sealing strips (53, 54, 55) is. Apparatus according to claim 12, characterized in that the sealing strips on their sides assigned to the edges of the side walls of the vacuum chambers (51, 52) are formed with grooves which are preferably T-shaped and by means of which they fit onto the edges of the side walls of the vacuum chambers (51, 52 ) are postponed. Device according to one of claims 12 and 13, characterized in that at least some of the sealing strips (53, 54, 55) are asymmetrical. Device according to one of the claims 4 to 14, characterized in that the spray tube (56) is designed with needle jet nozzles (57a) and with flat jet nozzles (57b).

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