EP1362948A1 - Process for dewatering a fibrous web - Google Patents

Abstract

In a process to de-water a web (12) feed of paper or carton, the web passes through a de-watering zone (E) in which the fluid is displaced by pressurized gas (14). The web is esp. transported through the de-watering zone supported by a porous membrane (18). The membrane is a perforated foil. The pressure exerted by the compressed air (14) is greater than the ambient pressure.

Description

According to a first aspect, the invention relates to a pressing device such as a multi-chamber press forming rollers, and in particular a uniform membrane for use in particular in such a pressing device, and a method for the production of a corresponding membrane.

Attempts have been made for many years, outside Use air pressure to push water out of a paper web. Instead of compressing a sheet at a press nip to the point expels water at the hydraulic pressure, as it does with normal Wet pressing is considered to remove more water and sheet volume could be maintained when air pressure was applied could be the hydraulic pressures generated by the nip to support. Such an attempt involves that a Multi-roll structure is provided which is a closed chamber forms, allowing air to circulate through the chamber, to transport moisture out of the paper web.

To provide an effective seal for a multi-roll chamber can be problematic. It is known to form a roller assembly in which rubber rollers are arranged in such a way that they with rollers interact with a solid surface. It's trying to get one to seal such chamber, a possible problem that a considerable Load on the roller structure may be required to avoid the Maintain sealing between the rollers. Accordingly, one is robust frame required to limit the roller structure. It is another possible attempt to seal such a chamber Problem that any cuts in the rubber surface easily would cause the entire roller to become unusable.

It has also been found that conventional wet pressing processes are very inefficient in that only a small part of a roller circumference is used to process the paper web. To this limitation some attempts have been made to overcome to adjust a firm, impervious tape so that an extended one Gap formed for pressing the paper web and thus the paper web is drained. One problem with such an approach, however, is that the impermeable band the flow of a drying fluid, such as air, prevented through the paper web.

Accordingly, there is a need for an improved fabric which enables improved dewatering of a continuous web and effective sealing of a chamber on the nips provides.

The solution according to the invention relating to the first aspect brings one improved drainage of a continuous web, such as Paper, with itself and enables effective sealing of a chamber on the nips in a press device.

According to the first aspect, the invention thus creates a uniform membrane for use in a press device. The press device comprises two longitudinally extending edge sections and a semipermeable section with a plurality of each other in Related pores. The semipermeable section is between the pair of longitudinally extending edge portions. The uniform membrane comprises a shaped fabric and has one Thickness less than about 2.54 mm (0.1 inches). The semipermeable Section has a permeability greater than zero and less than about 0.025 m / s (five CFM per square foot) as by the TAPPI test procedure TIP 0404-20 measured (see in particular claim 1).

In some of the particularly specified in subclaims 2 to 9 In embodiments, the pair is more longitudinally extending Tapered edge sections such that a cross section of the uniform Membrane has a trapezoidal shape. Likewise, the two are in the longitudinal direction extending edge sections preferably impermeable.

The invention according to the first aspect also provides a method for Manufacture the unified membrane and includes the steps that a Carrier fabric is provided that is very permeable and that many interconnected pores are formed in the carrier fabric be (see in particular claim 10).

It is an advantage of the present invention when it is in a press device is used with a pressurized chamber that is formed from multiple rollers that they have a predetermined fluid flow by a continuous web, such as a paper web, through and cause a mechanical pressure force on this can to improve drainage of the continuous web to promote.

It is another advantage of the invention when it is in a press device is used that the invention sealing a sub Pressurized chamber made up of several rollers on two or more nips supported.

Advantageous embodiments of the according to this first aspect of the invention proposed method are in subclaims 11 to 19 specified.

According to a second aspect of the invention there is a method for drainage a fibrous web, in particular a paper or cardboard web, provided, in which the fibrous web through a dewatering zone is carried out in which it is at least partially due to an application with pressurized displacement fluid, in particular Displacement gas is dewatered, the fibrous web together with a porous membrane through the drainage zone and through the membrane with the displacement fluid will (see claim 20).

Advantageous refinements of the Method according to this second aspect of the invention.

In particular, a membrane made of film material with through holes can be used as the membrane existing membrane can be used.

The pressure of the displacement fluid acting on the membrane is in particular greater than the ambient pressure.

In particular, in the method according to this second aspect of the invention again a membrane can be used as it is related with the first aspect of the invention.

The membrane can in particular be provided with coherent pores his.

According to a third aspect, the invention relates to a method for Drainage of a fibrous web, in particular a paper or Cardboard web in which the fibrous web passes through a drainage zone is carried out in which it is at least partially due to an application with pressurized displacement fluid, in particular displacement gas, is drained (see the preamble of claim 25). she according to this third aspect further relates to a device according to the Preamble of claim 34.

Water can be applied by applying a fluid or gas differential pressure be removed from a paper web. This process is called displacement drainage called. This will be in the pores between water in the fibers is blown out of the paper fleece. in the Compared to conventional wet pressing in a single or double felted nip, the finished paper has a higher specific volume with the same dry content as after the mechanical drainage. With the help of the displacement drainage process, too other important properties of the finished fibrous web such as bending stiffness, Porosity and opacity can be positively influenced (J.D. Lindsay: "Displacement dewatering to maintain bulk", Paperi ja Puu Vol. 74 / No. 3/1992). There has also been a corresponding apparatus arrangement proposed for the displacement drainage process (W. Kawka et al. E. Szwarcztajn: "Some results of investigations on the equipment for intensive dewatering and drying of porous papers, EUCEPA-79 International Conference, London, paper 31, p. 153).

Is a membrane on the side of the fluid or gas pressure over the Bring paper, so it takes place due to the pressure drop in the membrane a compression of the paper. Water is released from the fibers into the pores pressed between the fibers. This water is Differential gas pressure blown out of the pores. When using Experience has shown that a membrane has a higher dry content (Kari Räisänen: "High-Vacuum dewatering on a paper machine wire section - a literature review ", Paperi ja Puu, Vo. 78, No. 3, 1996).

The extent of this compression depends on the ratio of permeability the membrane and the nonwoven. With targeted compression can dry content and specific volume of the finished fibrous web can be set. The compression of the nonwoven can be done in the displacement drainage system in practice, however, only with difficulty control, because the membrane permeability in the operation of the production plant difficult to change. This results in the same for the rest Process conditions at a certain fluid or gas pressure certain dryness and a certain specific volume.

According to the third aspect, the aim of the invention is a method and to create a device of the aforementioned type with which the Result of the displacement drainage process in relation to the achieved dryness and paper technology properties of the finished Fibrous web such as, in particular, specific volume, porosity, surface roughness and / or the like can be controlled in a targeted manner.

With regard to the method, this task is performed according to the third aspect solved the invention in that the drainage zone in several Sections are divided in which the applied fluid or gas pressure is individually adjustable (cf. claim 25). The fibrous web preferably together with a membrane through the drainage zone passed and through this membrane with the displacement fluid or gas applied.

Because of this training, the extent of leaf compression and the level of the applied fluid or gas pressure can be controlled separately. The Drainage process can thus be set directly during operation or be optimized.

Advantageous refinements of the Method according to the third aspect of the invention.

So in a practical practical embodiment, the drainage zone in several lying one behind the other in the direction of web travel Sections divided in which the applied fluid or gas pressure individually is adjustable.

It is preferred to use displacement fluid or gas from one side acted upon fibrous web together with at least one wire or Felt tape passed through the drainage zone, the one on the other Web side is arranged.

Especially in the event that the initial drainage is gentle a low fluid or gas pressure is advisable viewed in a front section of the drainage zone in the direction of web travel a lower fluid or gas pressure is applied than in one Section lying further back in the direction of web travel.

If, for example, a high final dry matter content is required, it is advantageous viewed in at least one further in the direction of web travel rear section of the drainage zone a higher fluid or Gas pressure applied as viewed in a front direction of web travel Section.

In contrast, to achieve a relatively high volume of the finished Fibrous web further viewed in at least one in the web running direction a corresponding section of the drainage zone at the rear low fluid or gas pressure are applied.

In particular, in the method according to this third aspect of the invention again a membrane can be used as it is related with the first aspect of the invention and is particularly indicated in claims 1 to 19.

In the device according to the third aspect of the invention, the Task accordingly solved in that the drainage zone in is divided into several sections, in which the applied fluid or gas pressure is individually adjustable (see claim 34).

Advantageous embodiments are in the subclaims 35 to 42 of the device according to the third aspect of the invention.

In particular, in the device according to this third aspect again a membrane can be provided, as in the context with the first aspect of the invention has been described to us in particular is specified in claims 1 to 19.

According to a fourth aspect, the invention relates to a method for Drainage of a fibrous web, in particular a paper or Cardboard web in which the fibrous web passes through a displacement drainage zone is carried out in which it is at least partially due to an application with displacement fluid, in particular displacement gas, is drained (cf. the preamble of claim 43). According to this fourth aspect, a device according to the preamble of claim 49.

This fourth aspect of the invention is at least essentially concerned again with the one previously related to the third Aspect of the invention explained problems.

It is therefore again according to this fourth aspect of the invention The aim of the invention, a method and an apparatus of the aforementioned Way of creating the result of the displacement drainage process in terms of final dryness and paper technical properties of the finished fibrous web such as in particular specific volume, porosity, surface roughness and / or the like is specifically controllable.

With regard to the method, this task is performed according to the fourth aspect solved the invention in that the fibrous web moreover by a press upstream of the displacement drainage zone will (see claim 43).

Because of this training, the extent of leaf compression and the level of the applied fluid or gas pressure can be controlled separately. Through the press upstream of the displacement drainage zone the nonwoven can be pre-compacted to the desired size. In this way, in particular, the permeability of the nonwoven fabric in the desired way. By decoupling drainage and compacting process can thus have the properties the finished fibrous web or the finished paper become.

If the fleece is heavily pre-compacted, more water can be added be removed from the fleece. This is particularly the case with such types of paper required where primarily a high drainage content according to the press.

Advantageous refinements of the method according to the fourth aspect of the invention are specified in subclaims 44 and 48.
A shoe press or a roller press can be used as the upstream press.

The fibrous web can in particular together with a porous Membrane passed through the displacement drainage zone and through the membrane with the displacement fluid or gas become.

In particular, in the method according to this fourth aspect of the invention again a membrane can be used as it is related with the first aspect of the invention and is particularly indicated in claims 1 to 19.

In the device according to the fourth aspect of the invention, the Task solved accordingly in that the displacement drainage zone a mechanical press in particular is connected upstream and that the fibrous web first through the upstream press and is then led through the displacement drainage zone (cf. Claim 49).

In principle, a downstream mechanical press can also be provided his.

Advantageous further developments of the device according to the fourth aspect the invention are specified in the subclaims 50 to 54.

For example, a shoe press or a roller press can again be provided as the upstream press.
The fibrous web can in particular also be guided together with a porous membrane through the displacement dewatering zone and acted upon by the displacement fluid or gas through the membrane.

In particular, in the device according to this fourth aspect again a membrane can be provided, as in the context with the first aspect of the invention has been described to us in particular is specified in claims 1 to 19.

Fig. 1

eine teilweise schematische Seitenansicht einer Ausführungsform der vorliegenden Erfindung,

Fig. 2

eine perspektivische Seitenansicht der Anordnung der Walzen der Ausführungsform von Fig. 1,

Fig. 3

eine Teilfrontansicht der Anordnung der Walzen der Ausführungsform von Fig. 1,

Fig. 4

eine schematische Darstellung einer Variante einer Endabdichtungsplatte der vorliegenden Erfindung,

Fig. 5

eine schematische Darstellung einer Variante einer weiteren Endabdichtungsplatte der vorliegenden Erfindung,

Fig. 6

eine in übertriebenem Maßstab dargestellte Seitenansicht einer Variante eines Hauptwalzenprofils der Erfindung,

Fig. 7

eine schematische Darstellung einer Variante der Ausführungsform mit einer einzigen Kammer von Fig. 1,

Fig. 8

eine schematische Darstellung einer Ausführungsform der Erfindung, die zwei Kammern umfasst,

Fig. 9

eine Explosionsteilschnittansicht, die Kammerabdichtungsaspekte der vorliegenden Erfindung veranschaulicht,

Fig. 10

eine schematische Darstellung einer ersten Ausführungsform einer Vorrichtung zur Entwässerung einer Faserstoffbahn,

Fig. 11

eine schematische Darstellung einer weiteren Ausführungsform einer Vorrichtung zur Entwässerung einer Faserstoffbahn,

Fig. 12

eine schematische Darstellung einer ersten Ausführungsform einer Vorrichtung zur Entwässerung einer Faserstoffbahn und

Fig. 13

eine schematische Darstellung einer weiteren Ausführungsform einer solchen Entwässerungsvorrichtung.

The invention is explained in more detail below using exemplary embodiments with reference to the drawings. 1 to 9 relate in particular to the first, all of FIGS. 1 to 13 in particular also the second, FIGS. 10 and 11 in particular the third and FIGS. 12 and 13 in particular the fourth aspect of the invention, in principle also any combination of the various aspects the invention are possible. Show it:

Fig. 1

2 shows a partially schematic side view of an embodiment of the present invention,

Fig. 2

2 shows a perspective side view of the arrangement of the rollers of the embodiment from FIG. 1,

Fig. 3

2 shows a partial front view of the arrangement of the rollers of the embodiment from FIG. 1,

Fig. 4

1 shows a schematic representation of a variant of an end sealing plate of the present invention,

Fig. 5

1 shows a schematic representation of a variant of a further end sealing plate of the present invention,

Fig. 6

2 shows a side view, shown in an exaggerated scale, of a variant of a main roll profile of the invention,

Fig. 7

1 shows a schematic illustration of a variant of the embodiment with a single chamber from FIG. 1,

Fig. 8

1 shows a schematic representation of an embodiment of the invention, which comprises two chambers,

Fig. 9

4 is an exploded partial sectional view illustrating chamber sealing aspects of the present invention.

Fig. 10

1 shows a schematic representation of a first embodiment of a device for dewatering a fibrous web,

Fig. 11

1 shows a schematic representation of a further embodiment of a device for dewatering a fibrous web,

Fig. 12

a schematic representation of a first embodiment of a device for dewatering a fibrous web and

Fig. 13

is a schematic representation of another embodiment of such a drainage device.

Exemplary embodiments in particular of the first aspect of the invention (cf. Figures 1 to 9)

Corresponding reference symbols give corresponding views in the entire views Parts. The exemplary embodiments listed herein illustrate preferred embodiments of the invention, and such Embodiments are not considered to be the scope of the invention limiting any way to look.

In the drawings and particularly in Fig. 1 is a press assembly 10 shown, which is particularly useful in papermaking. The Press assembly 10 includes a frame 12, a load cylinder 14, a press roll arrangement 16, a tensioning structure 18, a membrane 20 and a control unit 21.

The frame 12 comprises a main frame 22, an upper swing frame 24, a lower swing frame 26, an upper swing arm 28, a lower swing arm 30 and a pair of side frames 32, 33. The Side frame 32 is shown with a portion broken away to one to expose the inner part of the side frame 33. The swivel arms 24, 26 are, for example by welding or screws, firmly on the Main frame 22 attached. The swivel arms 28, 30 are each about a plurality of pivots 34 are pivoted to the in a conventional manner Swing frame 24, 26 mounted. Each swivel arm 28, 30 has one first end 36, 38, which is designed such that it is opposite Ends 40, 42 of the loading cylinder 14 via pins 44 receives. Each swivel arm 28, 30 has a second end 46, 48, which is designed in this way, for example by welding or Screws that it receives the respective bearing housing 50, 52 firmly. The first and second side frames 32, 33 are on opposite sides of the main frame 22 mounted.

The press roll arrangement 16 comprises a plurality of rolls 60, 62, 64, 66 (four rollers as shown) that are used to co-operate in the rotation Frame 12 are arranged. By interacting rotation is meant that the rotational speed on the peripheral surface of each of the Rollers 60, 62, 64, 66 together are substantially the same, wherein in essentially no slip occurs between the roller surfaces. The For the sake of convenience, the rollers 60, 62 are sometimes the main rollers and rollers 64, 66 are referred to as pressure rollers.

2 and 3 are generally all rollers 60, 62, 64, 66th closed hollow cylinder, each with a first circular end 68, 70, 72, 74, a second circular end 76, 78, 80, 82 and one cylindrical, central peripheral surface 84, 86, 88, 90, and there are all each radially symmetrical about an axis of rotation 92, 94, 96, 98. One set Seals 99 may be formed at the first circular ends 68, 70, 72, 74 and the second circular ends 76, 78, 80, 82. The Main rollers 60, 62 and pressure rollers 64, 66 are arranged axially in parallel. The circumference of each pressure roller 64, 66 is smaller than the circumference of each Main roller 60, 62. According to FIG. 1, rollers 60, 62, 64, 66 are of this type arranged that they have a corresponding number of nips 100, Define 102, 104, 106.

The pressure rollers 64, 66 are used to run along a seal the axial extent of the main rollers 60, 62 at the nips 100, 102, 104, 106 to create. Each roller 60, 62, 64, 66 can be one elastic coating, such as rubber, to cover the Support sealing at the nips. The seal on the nips 100, 102, 104, 106 requires a relatively uniform Pressure along all nips 100, 102, 104, 106. With the probable Bending of the main rollers 60, 62 due to the application of force on this by the pressure rollers 64, 66 is some mechanism necessary to create a uniform gap pressure on the Support nips 100, 102, 104, 106. Accordingly can the pressure rollers 64, 66 hydraulic pressure and a series of pistons inside the roll shell of rolls 64, 66 to the roller shell of the rollers 64, 66 in the roller shell of the main rollers 60, 62 to press to even pressure on the associated Provide columns. Alternatively, a crowned or a deflection compensation pressure roller could be used be used.

3, the first and second side frames 32, 33 each include a first and a second sealing plate 108, 110, respectively, which are connected to a Are mounted on the inside of these. The first and the second sealing plate 108, 110 are forced by the side frames 32, 33 to with part of the first circular ends 68, 70, 72, 74 or a part of the second circular ends 76, 78, 80, 82 of the rollers 60, 62, 64, 66 of the press roll assembly 16 to engage to define a chamber 112 and thus an end seal of the chamber 112 to effect. At least one tension rod 113 is optional between a first sealing plate 108 and a second sealing plate 110 switched in the chamber 112. In some embodiments the first and second sealing plates 108, 110 are flexible and constructed and designed in such a way that they are essentially identical the shape of the first circular ends 68, 70, 72, 74 and second, respectively Adjust circular ends 76, 78, 80, 82 of rollers 60, 62, 64, 66. To further aid the sealing of chamber 112, seals are between the first and second sealing plate 108, 110 and the first and second circular ends 68, 70, 72, 74 or 76, 78, 80, 82 arranged. Such seals can be mechanical Seals and fluid seals include.

The main rollers 60, 62 are used on the side frames 32, 33 conventional bearing mounting structures, such as those, the rolling bearings or sockets included, permanently rotatably mounted. In this context means rotatably mounted that the position of the axes 92, 94 of the rollers 60, 62 with respect to the main frame 22 and the side frames 32, 33 not moved after installation, but a rotation is allowed around axes 92, 94.

Preferably, the main roller 60 includes the membrane 20 in Fluid communication with chamber 112 is at least one void in Shape of a groove, a hole and a pore in its central peripheral surface is formed to a pressure difference across the membrane 20th and any intermediate material such as the continuous web 140 to ease away. The main roller 62, which is not in fluid communication with the chamber 112 over the membrane 20 preferably comprises no such void in its central peripheral area. each The roller can have an elastic coating, such as rubber, over it cover all or part of their roll surface to the Sealing of the chamber 112 at the nips 100, 102, 104, 106 support.

The pressure rollers 64, 66 are each rotatable on bearing housings 50, 52 assembled. However, the axes of rotation 96, 98 of the rollers 64, 66 are related movable on the main frame 22 via swivel arms 28, 30 in order to to cause a load on the press roll assembly 16. Because the scope and the corresponding diameter of each pressure roller 64, 66 is preferred smaller than the circumference and the corresponding diameter of each Main roller 60, 62 are those generated on the pressure rollers 64, 66 Forces are reduced, causing smaller structures to generate forces within the Can hold chamber 112.

For example, the pressure rollers 64, 66, which are relatively smaller, require a lower actuation force than a relatively larger counter-pressure roller would do. If the diameter of the pressure rollers 64, 66 a One third of the diameter of the main rollers 60, 62 can be on the pressure rollers 64, 66 applied forces in comparison with the forces to the main rollers 60, 62 can be reduced by 40 percent.

The closer the distance between the main rollers 60 and 62, and each greater the diameter difference between the main rollers 60, 62 and Pressure rollers 64, 66, the larger the difference in general Forces exerted by the main rollers 60, 62 and the pressure rollers 64, 66 the frame 12 is exercised. This arrangement allows the Support structure, e.g. the frame 12, for the press roll assembly 16 easier becomes. For example, since most of the force is due to the relative larger main rollers 60, 62 are exerted, the main rollers 60, 62 mounted on bearings that are fixedly attached to the side frames 32, 33 are, which in turn are fixedly attached to the main frame 22. By doing the main rollers 60 and 62 are structurally interconnected and theirs relative positions are fixed, the main forces within the Press assembly 10 within a relatively simple mechanical Structure maintained.

In order to keep the membrane 20 under a suitable operating voltage, the clamping structure 18 is mounted on the main frame 22. The clamping structure 18 comprises a tensioning cylinder 114 and a tensioning roller 116. The tension roller 116 is rotatably coupled to the tension cylinder 114 the tension roller 116 in a direction transverse to the axis of rotation of the tension roller 116 moves.

As shown in FIG. 1 in relation to FIG. 2, the membrane moves 20 in the direction of arrow 118 and is over part of the circumferential surface 88 of the pressure roller 64 passes, runs into an inlet nip 100 runs in over part of the peripheral surface 84 of the main roller 60 within chamber 112, runs out of outlet nip 102 out, runs over part of the peripheral surface 90 of the pressure roller 66 away and runs about half the circumferential surface of the tension roller 116 around. The membrane 20 is preferably a continuous one Tape made of a semi-permeable material that is is structured and designed to have a predetermined permeability having a predetermined fluid flow therethrough allowed. The semipermeable membrane 20 is likewise preferred up to a limited degree of both gas permeable and liquid permeable. In addition, the membrane 20 is structured and designed such to seal chamber 112 at inlet gap 100 and at Outlet gap 102 supported. In the chamber 112 after this under The combined effect of the inlet gap serves to pressurize 100, the membrane 20, which in the circumferential direction around the main roller 60 runs around and the outlet gap 102 to a single extended Gap 115 for applying a mechanical compressive force in the direction the main roller 60 and any intermediate material, which is arranged between the membrane 20 and the main roller 60 to form. Thus, the membrane 20 is with the pressurized chamber 112 and the main roller 60 in connection to simultaneously a predetermined fluid flow through the intermediate material through and to cause a mechanical pressure force on this.

In preferred embodiments, membrane 20 is approximate 2.54 mm (0.1 inch) or less thick and includes a molded fabric that Semi-permeable is made by connecting several together standing pores 117 (shown by dots in Fig. 6) in the molding fabric are formed that have a size, shape, frequency and / or pattern have, which is selected so that the desired permeability is provided becomes. The permeability is chosen to be greater than zero and is less than about 0.025 m / s (five CFM per square foot) as through measured the TAPPI test method TIP 0404-20, and is particularly preferred chosen to be greater than zero and less than approximately Is 0.010 m / s (two CFM per square foot). Therefore, the semipermeable Membrane 20 to a limited degree both gas permeable and liquid permeable.

The membrane 20 is made semi-permeable by a carrier fabric is assumed that is very permeable, and then several interconnected pores 117 in the carrier fabric be formed. A padding is applied to the base fabric, which is a mixture of meltable over heat and not over Heat fusible fibers is made. The padding from the fiber mixture is sewn into the base fabric. On the sewn carrier fabric heat is applied to the heat-fusible fibers to melt, which in turn empty spaces in the form of each other related pores similar to those of a foam sponge, leave behind.

The membrane 20 preferably comprises two tapered, impervious, longitudinally extending outer edges 20A, 20B, which are adjacent the semipermeable section of the membrane 20 with the one another in Connected pores 117 are formed. The outer edges 20A, 20B can be made impermeable by using heat fusible fibers on the outer edges of the membrane 20 in the absence are melted by fibers which cannot be melted by heat.

The fiber mixture can be sewn into the carrier fabric to create a Flow resistance layer near the surface of the membrane 20 which will be located closest to chamber 112. Therefore, in operation, when it is exposed to chamber pressure, the pressure drop across the membrane 20 close to the chamber surface of membrane 20 occur, causing the membrane 20 entrains a minimal amount of chamber air. Since the membrane is entrained, will release pressurized fluid when out of the Chamber runs out, it is desirable, the entrained fluid volume set up as small as possible to waste from under pressure to avoid chamber fluid. Therefore, it is preferred to use the flow resistance layer close to the surface of the chamber Membrane and it is preferred to make the tissue as thin as possible preferably less than 2.54 mm (0.1 inches). additionally it is preferred to keep the membrane void percentage as low as possible, preferably less than 40 percent. The chamber side The surface is preferably also abrasion-resistant. The rest of the Fabric that does not include the fiber blend can serve as a fluid distribution layer act which is a fluid flow from the resistance layer picks up and the fluid flow over the underlying continuous Lane 140 distributed.

Alternatively, the interconnected pores 117 of FIG Membrane 20 formed by coating layers on the base fabric be applied until the desired permeability is reached. The Permeability is set by changing any parameter from: the type of coating, the entrainment of air into the carrier, to form a foam, and adjusting the solids content of the Coating. The coating process is stopped when the desired one Flow resistance level of the membrane 20 is reached.

The control unit 21 comprises a controller 120, a compressed air source 122, a fluid source 124, a differential pressure source 125 and a sensor assembly 126th

Controller 120 preferably includes a microprocessor and one Memory for storing and executing a control program, and includes an I / O device for establishing input / output communication and data transfer with external devices. The For example, controller 120 may be an industrial programmable Controllers of a type that is well known in the art.

The compressed air source 122 comprises several individually controllable outputs. The compressed air source 122 is connected to the loading cylinder 14 via a Line 128 fluidly coupled. The compressed air source 122 is also with the Tensioning cylinder 114 fluidly coupled via line 130. While the preferred Working fluid to operate cylinders 14, 114 compressed Experts will find that the compressed air system is against air another fluid source could be exchanged that is a different gas or a liquid working fluid is used.

Fluid source 124 is fluidly coupled to chamber 112 via line 132. The type of fluid is dependent on the type of the user Material that the press assembly 10 processes is selectable. For example compressed air may be desirable in some applications to use the chamber 112 to a predefined To pressurize pressure in preferred embodiments of the Invention is a pressure greater than 30 psi above the pressure of the differential pressure the differential pressure source 125. For other applications it may be desirable to use a pressurized gas such as a heated one Gas, or a liquid, such as water, or a liquid solution too use.

In the embodiment of FIG. 1, fluid flows into chamber 112 the line 132 flows in and flows out of the chamber 112 over the empty spaces, for example grooves, holes or pores in the central peripheral surface 84 of the main roller 60 are formed. The white spaces in the main roller 60 are connected to the differential pressure source 125 Line 133 in connection. The differential pressure source 125 can, for example a negative pressure source, a pressure source that works at a pressure, which is lower than the pressure in chamber 112, or simply one Vent to the atmosphere via line 133 to the inside of the Roller 60 is coupled to effect an evacuation of the empty spaces.

Alternatively, no ventilation via line 133 is necessary if the Main roll 60 includes grooved spaces and the grooves associated with atmospheric pressure. Venting can be similar can be eliminated via line 133 if the roll empty spaces, such as Blind holes that are large enough and when pressed into the gap occur which is lower than the chamber pressure. In this case the empty spaces act as a differential pressure source until the empty spaces reach the chamber pressure. The empty space size can be chosen in this way be controlled that the effectiveness of the drainage process becomes.

The pressurized chamber 112 includes its own pressure relief, by causing excessive pressure build-up in chamber 112 will result in one or more rollers 60, 62, 64, 66 opening, to relieve the pressure instead of catastrophic failure.

The controller 120 is electrically connected to the compressed air source 122 Electrical cables 134 connected to selectively select the fluid outlet therefrom control and thus the operation of the loading cylinder 14 independently control and create a load on the press roll assembly 16, and to control the operation of the tensioning cylinder 114 independently and thus a predetermined voltage on the semipermeable membrane 20 to create.

Controller 120 is electrical with fluid source 124 via an electrical cable 136 connected. Controller 120 is also electrical with the Sensor assembly 126 connected via an electrical cable 138. The sensor structure 126 includes one or more sensor mechanisms to detect electrical To provide feedback signals to controller 120, either one or any combination of a pressure, a temperature or one represent another environmental factor within chamber 112. The Controller 120 processes the feedback signals to output signals generate, which are supplied to the fluid source 124 to selectively Control fluid output from this.

In operation, controller 120 processes from sensor assembly 126 received feedback signals to a pressure of the under pressure set chamber 112 preferably to control a pressure that is greater than 30 psi above the pressure of the differential pressure source 125. The Rollers 60, 62, 64, 66 are interposed with little or no slip this is rotated and the membrane 20 is moved at the same speed as the surface speed of the rollers 60, 62, 64, 66 driven. A continuous web or paper web 140 and a web support layer 142 are in the inlet nip 100 in the direction of arrow 143 and initiated by the membrane 20 through the extended Nip 115 passed through to outlet nip 102. The membrane 20 is arranged inside the roller assembly 16 so that it is adjacent a first side 144 of the continuous path 140 is about the direct connection with the pressurized chamber 112 is effective to separate. In other words, the fluid in chamber 112 cannot on continuous web 140 except through membrane 20 Act.

The web support layer 142 is arranged in such a way that it coincides with the cylindrical Middle surface 84 of the main roller 60 is in contact and that it in contact with a second side 146 of the continuous web 140 stands.

The membrane 20 is structured and designed such that it is a Permeability has a predetermined fluid flow through it through to the continuous path 140, and stands with the pressurized chamber 112 and at least one void of the Main roller 60 in connection to a pressure difference across the membrane 20 and to produce the continuous path 140. This pressure drop causes a mechanical pressure force on the continuous Web 140 is applied, which helps to solidify them. Therefore stands the membrane 20 with the pressurized chamber 112 and the Main roller 60 in combination to simultaneously combine a predetermined one Fluid flow through the continuous path 140 and to cause a mechanical pressure force on this and thus a to promote improved drainage of the continuous web 140.

The invention is particularly advantageous if the dry matter content of the continuous web 140 before dewatering is greater than about 6 percent and less than about 70 percent, and if the basis weight of the continuous web 140 is greater than about 25 g / m ² .

The web support layer 142 preferably has a thickness of approximately 2.54 mm (0.1 inch) or less and can be a felt or alternatively comprise a felt which is arranged next to a hydrophobic layer, the hydrophobic layer adjacent to the second side 146 of the continuous Lane 140 is arranged. The web carrier layer 142 comprises preferably a felt layer 142A that is integral with a hydrophobic Layer 142B is formed, the hydrophobic layer 142B being water transported away from the continuous web 140 via capillary action, so that it is absorbed by the felt layer 142A (see Fig. 6). The hydrophobic layer 142B provides an effect of post-wetting protection ready, which prevents water from getting back into the continuous path 140 flows.

The relative sizes of the applied to the continuous web 140 mechanical pressure is caused by factors such as the chamber pressure in chamber 112, the permeability of the semipermeable Membrane 20 and the permeability of the continuous web 140. The fluid flow, preferably air, through the continuous path 140 is influenced by factors such as the Chamber pressure in chamber 112, the permeability of the semipermeable Membrane 20 and the size (e.g. length) of chamber 112. The dynamic Fluid pressure in the pressurized chamber 112 is on the Basis for monitoring the chamber pressure through the sensor structure 126 controlled. The sensor assembly 126 detects a pressure within the Chamber 112 and provides a pressure feedback signal to the controller 120. Controller 120 processes the pressure feedback signal to generate a pressure output signal that is supplied to the fluid source 124 to selectively control their fluid output and thus pressure the pressurized chamber 112 at a predetermined pressure, preferably a pressure greater than 30 psi above the pressure of the Differential pressure source 125 is to control. If a temperature in Relation to a pressure within the pressurized chamber 112 is relevant, the sensor assembly 126 can be adapted in such a way that it senses a temperature within chamber 112 and a temperature feedback signal supplies. Controller 120 processes this Temperature feedback signal together with the pressure feedback signal, to generate output signals from the fluid source 124 supplied to the pressure and temperature in the under pressure set chamber 112 to regulate.

The controller 120 also controls the load on the main rollers 60, 62 by the platen rollers 64, 66 by controlling a print size that the load cylinder 14 on the upper and lower swivel arms 28, 30 applies. The load size of the main rollers 60, 62 is preferably with pressure in the pressurized chamber 112 in Relationship monitored by a pressure sensor of sensor assembly 126 becomes. The load can be a preload in addition to a load include, which is proportional to the pressure in the chamber 112.

Of course, there are changes to the embodiment described above possible. For example, and according to Fig. 4, the end seal of the Chamber 112 maintain and wear between the sealing plates 108, 110 and the rollers 60, 62, 64 and 66 to prevent a lubricating and sealing fluid, such as air or water, or any viscous fluid in a plurality of sealing openings 148 via a line ring 150 are pressed in, with a fluid source 152 via a Line 153 is coupled. The pressure fluid source 152 is electrical with the Controller 120 is coupled via an electrical cable 155 and is thereby controlled. The sealing openings 148 in the sealing plates 108, 110 are arranged so that they end the rollers 60, 62, 64, 66 are facing to pressurized lubricating and sealing fluid between the sealing plates 108, 110 and parts of the respective forward circular ends 68, 70, 72, 74 and 76, 78, 80, 82. Float due to the injection of the lubricating and sealing fluid the sealing plates 108, 110 over the circular ends 68, 70, 72, 74 and 76, 78, 80, 82 in small controllable distances with little or without physical contact between the sealing plates 108, 110 and the circular ends 68, 70, 72, 74 and 76, 78, 80, 82 of the Rollers 60, 62, 64, 66. Although there is a leak around such a seal assembly around, the size of the leak is due to the careful Selection of distance tolerances and the lubricating and sealing fluid so controllable that it is small.

In addition, the main roller 62 is also intended to be vented to a differential pressure source and that includes the continuous path 140 together with the membrane 20 such that it passes through all four columns run out, such as into gap 106 Gap 104 out, into gap 100 and out of gap 102 to the Increase residence time over which the membrane 20 with the continuous Lane 140 interacts.

Fig. 5 shows a further variant of the invention, in which the end seal chamber 112 is improved by fluid openings 154 in sealing plates 108, 110 are arranged such that they are close to the Ends of the rollers 60, 62, 64, 66 but not arranged facing them are. A lead ring 156 is coupled to openings 154 and is coupled to fluid source 152 via line 158 to provide lubrication and Sealing fluid, such as air or water, or any other viscous fluid through openings 154 into chamber 112 feed into it. The fluid source 152 is electrical with the controller 120 coupled via electrical cable 155 and is thereby controlled. The Pressure in chamber 112 pushes the added fluid between them circular ends 68, 70, 72, 74 and 76, 78, 80, 82 of the rollers 60, 62, 64, 66 or the sealing plates 108, 110, which allows that the sealing plates 108, 110 over the circular ends swim. In this embodiment, the leakage is controlled by the distance between the circular ends 68, 70, 72, 74 and 76, 78, 80, 82 of the rollers 60, 62, 64, 66 or sealing plates 108, 110 is controlled such that there is no excessive leakage in any area occurs and that excessive wear between the sealing plates 108, 110 and rollers 60, 62, 64, 66 is prevented.

Fig. 6 shows a further variant of the invention, in which a main roller 160, which has the profile shown, would replace the main roller 60. The main roller 160 includes a first circular end 162, a second circular end 164, a first cylindrical end surface 166 and a second cylindrical end surface 168, a first inclined ring surface 170, a second inclined ring surface 172 and a cylindrical central surface 174. The first cylindrical end surface 166 is adjacent to the first circular End 162 arranged, and the second cylindrical end surface 168 is adjacent the second circular end 164. The cylindrical middle surface 174 has a circumference that is smaller than the circumference of the first and the second cylindrical end surface 166, 168. The first inclined Annular surface 170 forms a transition from the cylindrical central surface 174 ready for the first cylindrical end surface 166, and the second inclined Annular surface 172 forms a transition from the cylindrical central surface 174 ready for second cylindrical end surface 168.

The width of the cylindrical central surface 174 is selected such that it is approximately equal to the width of the membrane 20. The first and the second inclined ring surface 170, 172 define a guide path for the Membrane 20, continuous web 140 and the web support layer 142. Each includes membrane 20 and web support layer 142 preferably two tapered outer edges, the first and the second Touch inclined ring surface 170, 172. Particularly preferably comprises the permeable membrane 20 two tapered, impervious, lengthways extending outer edges 20A, 20B which are adjacent to a semipermeable Part 20C are formed to seal along the inclined To improve ring surfaces 170, 172. The web carrier layer likewise preferably comprises 142 a felt layer 142A and a hydrophobic layer 142B. The web backing layer 142 can optionally have two impermeable, include longitudinally extending outer edges which are the first and touch the second inclined ring surface 170, 172.

7 schematically illustrates a further variant of the invention, in which a press arrangement 200 has a roll assembly 201 with several Rollers 202, 204, 206, 208 includes which are arranged in a square pattern interacting rotation when processing a first continuous Web 209, such as a paper web on a web Web carrier layer 210 is entrained, and a second continuous Web 212, such as a paper web, on a web support layer 214 is taken, is arranged. The web support layers 210, 214 can be felt layers, for example.

Each of the plurality of rollers 202, 204, 206, 208 is from the previous one described as main rollers 60, 62 and / or 160 and pressure rollers 64, 66 Type and is therefore not described in detail again. It is also to understand that sealing plates of the same general type, as described above in relation to the sealing plates 108 and 110 were in the manner described above with reference to FIGS. 4 and 5 would be used to define a chamber 216. The tax- and pressure source connections for chamber 216 and the associated one Operations are as described above with reference to FIGS. 1-4 was, which is therefore not repeated here.

For purposes of this discussion, rollers 202 and 204 will be the main rollers and the rollers 206, 208 are called pressure rollers , although in the present embodiment the rollers 202, 204, 206, 208 have approximately the same size. The main rollers 202, 204 and the pressure rollers 206, 208 are arranged so that they define multiple nips 220, 222, 224, 226, of which on the Basis of the rotation of the main roller 202 in the direction indicated by the arrow 230 direction shown the nips 220, 224 inlet nips of the Form press assembly 200 and nips 222, 226 nip nips form.

The first continuous web 209 and the first web support layer 210 enter inlet gap 220 and pass through chamber 216 processed around the circumference of the main roller 202. The second continuous web 212 and second web support layer 214 enter inlet gap 224 and pass through chamber 216 processed around the peripheral surface of the main roller 204. The first web support layer 210, the continuous web 209, the continuous Web 212 and second web support layer 214 are through processed through the outlet gap 222 to form a laminated web 228 to form, which consists of the continuous tracks 209, 212. While processing remains due to the second continuous path 212 the surface tension or due to the ventilation in the Main roller 202 through holes, grooves or pores in the cylindrical Surface of the main roller 202 are formed in contact with the first continuous Lane 209. The second is contemplated to be continuous Web 212 and the second web support layer 214 through one on the continuous Web 209 applied coating layer to be replaced could.

8 is a schematic illustration of another embodiment of the invention, in which a press assembly 300 comprises a roller assembly 301 with a plurality of rollers 302, 304, 306, 308, 310 and 312, which for interacting rotation when processing a continuous Web 314, such as a paper web, are arranged. each Roller 302, 304 is of the type previously described as main roller 60 and / or 160 Kind and is with a differential pressure source in a way fluid coupled, which is described above. Rollers 306, 308, 310, 312 are of the above in terms of non-vented main and pressure rollers, such as the main roller 62 and the pressure roller 64 Type and are therefore not described in detail again. Likewise sealing plate 316 of the same general type as above with respect to the sealing plates 108 and 110, and can be used in the manner described above with reference to FIGS. 4 and 5 become.

For the purposes of this discussion, rollers 302 and 304 will be the main rollers and rollers 306, 308, 310 and 312 are referred to as Called pressure rollers, due to their respective main function within a given chamber with respect to the continuous path 314. In the present embodiment, the rollers 302, 304, 306, 308, 310 and 312 are approximately the same size. The main rollers 302, 304 and pressure rollers 306, 308, 310, 312 are arranged in such a way that they define multiple nips 320, 322, 324, 326, 328, 330, 332, on the basis of which a rotation of the main roller 302 in the through the direction shown by arrow 334, the nips 320, 326, 330 Inlet nips of the press assembly 300 form the nips 322, 328, 332 form outlet nips and the nip 324 an Chamber division gap is. The orientation and / or size of the rollers 302, 304, 306, 308, 310 and 312 can be modified such that the Roll nips are arranged in the desired locations and efficiency processing is optimized.

The sealing plates 316 together with the rollers 302 define 304, 306, 308, 310 and 312 a first chamber 336 and a second Chamber 338, each chamber having at least one inlet gap and at least one an outlet gap is assigned.

A first pressure source 340 is connected to a chamber 336 via a line 342 fluidly coupled, and a second pressure source 344 is with a chamber 338 fluidly coupled via a line 346. Lines 342 and 346 each extend from the sealing plate 316 into the chambers 336 and 338, respectively, to distribute fluid flow therein. The Controller 120 is electrical with pressure source 340 via an electrical cable 348 and is electrically connected to pressure source 344 via a Electric cable 350 coupled. A sensor assembly 352 is electrical with the Controller 120 connected via an electrical cable 354. The sensor structure 352 is designed to measure the pressure and temperature of each Chamber 336, 338 monitored.

The press assembly 300 further includes a first semipermeable membrane 360 and a second semipermeable membrane 362. The membranes 360, 362 stand with the peripheral surfaces of the main rollers 302, 304 in Interaction to a first extended gap 364 and one to define second extended gap 366. The extended gap 364 is in the first chamber 336 and the extended gap 366 is located in the second chamber 338.

The continuous path 314 includes a first side 370 and a second Page 372. While in chamber 336, a fluid flows through continuous path 314 in a first direction from the first side 370 to the second side 372 on the extended one Gap 364. A fluid flows while in chamber 338 through the continuous path 314 in a second direction which is opposite to the first direction, from the second side 372 to the first Page 370 at the extended gap 364. A first membrane 360 is in communication with the first chamber 336 and the main roller 302 to a mechanical pressing force on the continuous path 314 in the first direction, i.e. from the first side 370 to the second side 372 applied. A second membrane 362 stands with the second chamber 338 and the main roller 304 in connection to a mechanical pressing force onto the continuous path 314 in the second direction, i.e. from the second side 372 to the first side 370. Stand by this the membranes 360, 362 are each pressurized Chambers 336, 338 and the respective main rollers 302, 304 in connection, around a predetermined fluid flow in combination and a mechanical pressing force on the continuous web 314 in cause two directions and thus improved drainage to promote the continuous path 314. In the present embodiment the main rollers 302, 304 each include at least one White space, such as a hole, a groove or a pore, to a pressure difference over the continuous path 314.

Preferably, each of the first semipermeable membranes 360 and the second semipermeable membrane 362 from a molded fabric approximately 2.54 mm (0.1 inch) or less thick and semi-permeable, by a plurality of interconnecting pores 117 in the Shaped fabrics formed with a size, shape, frequency and / or pattern are selected such that the desired permeability is created as described more fully above in connection with membrane 20 is. The permeability of each of the first semipermeable Membrane 360 and the second semipermeable membrane 362 chosen to be greater than zero and less than approximately 0.025 m / s (five CFM per square foot) is as by the TAPPI test procedure TIP 0404-20 measured, and especially greater than zero and less than is about 0.01 m / s (two CFM per square foot).

In preferred embodiments, press assembly 300 includes a first web support layer 361 and a second web support layer 363, each on opposite sides of the continuous web 314 are arranged. 8 is the first web support layer 361 arranged between the membrane 362 and the rollers 302 and 312, and the second web support layer 363 is between the membrane 360 and rollers 306 and 304. Alternatively, the first web support layer 361 can be arranged such that they are between the continuous Web 314 and membrane 362, and the second web support layer 363 may be arranged to be between the continuous path 314 and membrane 360. Preferably each of the web support layers 361, 363 is an integral fabric that a felt layer and a hydrophobic layer with a total thickness of about 2.54 mm (0.1 inch) or less, and is oriented so that the hydrophobic layer faces the continuous web 314 is.

8, the extended columns 364 and 366 essentially have the same length. However, the gap lengths can vary be what can be effected, for example, by main rollers chosen with different sizes and / or by the circumference size is changed by any one or more of the pressure rollers to effectively the location of one or more nips 320, 324 and 328 to change.

The internal pressure of each of the first chamber 336 and the second Chamber 338 is individually controlled by controller 120 and can be pressurized to different pressures. The chamber 338 is preferably at a pressure greater than the chamber pressure 336 pressurized. In some cases it may also be desirable be to fill the chamber 336 with a first material and the Chamber 338 with a second material that is from the first material is different to fill. Such materials can include dry air, Include steam or gas, water or other fluid.

In addition to controlling the pressures in the chambers 336, in some cases it is desirable to control the temperatures of the chambers 336, 338 to the same or possibly different temperatures.
FIG. 8 also shows a temperature control unit 374 which is fluidly coupled to respective chambers 336, 338 via lines 376, 378 in order to supply heating or cooling fluid, such as air, to the chambers 336, 338. The temperature control unit 374 is electrically coupled to the controller 120 via an electrical cable 380. The controller 120 receives temperature signals representing the temperatures of the chambers 336, 338 from the sensor assembly 352. The controller 120 then uses these temperatures to generate temperature output signals based on predefined target temperatures that are supplied to the temperature control unit 374. The temperature control unit 374 then responds to the temperature output signals to control the temperatures of the chambers 336, 338. The temperature of chamber 338 is preferably controlled to be higher than the temperature of chamber 336.

Alternatively, the temperature control of the chambers 336, 338 can be effected by the temperature of each of the first pressure source 340 and / or the second fluid source 344 to the respective chambers 336, 338 supplied fluids is regulated. In such a case, the temperature control unit 374 can be eliminated.

FIG. 9 shows a part of the roller arrangement 400, which has a main roller 402 and a platen roller 404 which replaces those previously described Main rollers or pressure rollers can be used.

The main roller 402 has a general structure similar to that of FIGS Main roller 160 shown in FIG. 6 corresponds. While in Fig. 9 only one right end portion 406 of main roller 402 is shown that the left end of roller 402 is a mirror image of right end 406 and thus the same reference numerals used to denote the to describe the right end 406 for the left end of the main roller 402 will apply.

The main roller 402 includes a cylindrical central surface 408, left and right right circular ends 410, left and right cylindrical end faces 412 and left and right inclined ring surfaces 414. The cylindrical End faces 412 are located adjacent respective circular ends 410. The cylindrical central surface 408 has a circumference that is smaller than the circumference of the cylindrical end faces 412. The inclined ring surfaces 414 represent a transition from the cylindrical central surface 408 to the cylindrical end faces 412. The cylindrical middle surface 408 includes at least one void, such as a groove, hole, or one Pore to a pressure difference across the membrane 20 and any intermediate To lighten material.

The distance between the inclined ring surfaces 414 of the main roller 402 is chosen such that it is approximately equal to the width of the semipermeable Membrane 20 is. The inclined ring surfaces 414 define a guide path for the semipermeable membrane 20 and the web carrier layer 142. Preferably, each comprises the semipermeable membrane 20 and the web support layer 142 two tapered outer edges touch the inclined ring surfaces 414. Particularly preferably includes the semipermeable membrane 20 two tapered, impervious, in Longitudinally extending outer edges 20A, 20B (see Fig. 6) to the Improve sealing along the inclined ring surfaces 414. The Web backing layer 142 includes a felt layer 142A and a hydrophobic Layer 142B. The profiles of the semipermeable membrane 20 and the Web carrier layer 142 are preferably dimensioned such that they are in the roll profile of the main roll 402 between the inclined ring surfaces 414 fit so that the membrane 20 and the cylindrical end faces 412 have essentially the same circumferential height. Would be in operation a continuous web, such as a paper web (not shown) between the semipermeable membrane 20 and the web carrier layer 142.

Interchangeable end seals 416 are at the circular ends 410 attached that include multiple fluid cavities 418. The attachment is caused by glue or fasteners. The interchangeable End seals 416 are preferably made of an elastic material, such as rubber, and can be a reinforcing fabric, such as nylon or steel.

The pressure roller 404 comprises a generally cylindrical structure, that corresponds to that of the pressure roller 64 shown in FIGS. 1-3.

While only a right end portion 420 of the platen 404 in FIG. 9 it can be seen that the left end of the platen 404 is on Is mirror image of the right end 420 and thus the same reference numerals, used to describe the right end 420 will apply to the left end of the platen roller 404.

The platen roller 404 includes a cylindrical central surface 422 and left and right circular ends 424. A sealing sleeve 426 with a Inner surface 428 and an outer surface 430 is over the cylindrical Middle surface 422 recorded and in a fixed relationship with the Pressure roller 404 held due to frictional forces between the cylindrical middle surface 422 and the inner surface 428 of the sealing sleeve 426 act. Alternatively, the sealing sleeve 426 can be glued or by fasteners located under the outer surface 430 of the Sealing sleeve 426 arranged and in the cylindrical central surface 422 are added to be held in their place. Preferably however, each sealing sleeve 426 is interchangeable such that when the Sealing sleeve 426 shows an unacceptable amount of wear, the sealing sleeve 426 without the need to press roller 404 to throw away, can be exchanged. The sealing sleeve 426 includes stress layer 432 and multiple fluid cavities 434th

Interchangeable end seals 436 are at the circular ends 424 attached, which comprise a plurality of fluid cavities 438. The attachment is effected by means of glue or fasteners. The interchangeable End seals 436 are preferably made of an elastic Material, such as rubber, and can be a reinforcing fabric, such as nylon or steel.

The sealing sleeve 426 is preferably made of an elastic material, such as rubber. The stress layer 432 of the sealing sleeve 426 is used to reduce the hoop or strapping tension and / or stresses on the sealing sleeve 426 to hold over the machine and includes a reinforcing fabric such as nylon or steel. The size, shape and geometry of fluid cavities 434 are selected to be, in particular in the vicinity of the longitudinally extending edges 20A, 20B of FIG semipermeable membrane 20 are elastically deformable. Likewise preferred the fluid cavities 434 either extend circumferentially the sealing sleeve 426 around in a repeated pattern Width of the platen 404, or across the width of the platen 404 in a repeated pattern around the circumference of the sealing sleeve 426 around. Alternatively, the cavities 434 can be diagonal extend around the sealing sleeve 426.

The fluid cavities 434 are filled with a fluid, such as air, Water or gel, pressurized to be a compliant but firm Seal with the semipermeable membrane 20 around the cylindrical Main end surfaces 412 of the main roller 402 maintain. With a shape of the invention, the fluid cavities 434 at the time of manufacture the sealing sleeve 426 is pressurized. Alternatively, the Compressed air cavities 434 at the time the sealing sleeve is manufactured 426 not put under pressure, but rather that Sealing sleeve 426 comprise one or more valve opening (s) 440, such as the type commonly used to inject air initiate a pneumatic tire to receive fluid and thus the cavities To put 434 under pressure. Alternatively, the valve opening (s) 440 open openings that communicate with a fluid source via a fluid line and a rotatable fluid coupling are connected. In some applications it may be desirable to close fluid cavities 434 together connect to distribute any external forces and effectively form a single cavity.

The fluid cavities 418, 438 of the interchangeable end seals 416, 436 are pressurized with a fluid such as air, water or gel. The size, shape and geometry of the cavities 418, 438 are such chosen that they are resiliently deformable to give a resilient fixed seal between the interchangeable end seals 416, 436 and with the associated sealing plates, such as the sealing plates 108, 110 of Fig. 3. In one form of the invention the fluid cavities 418, 438 at the time of manufacture of the End seals 416, 436 pressurized. Alternatively, the fluid cavities 418, 438 at the time of making the end seals 416, 436 not pressurized. Rather, the interchangeable ones End seals 416, 436 each have one or more valve opening (s) 442, 444 include, such as the type commonly used for this to inject air into a pneumatic tire to absorb fluid and thus pressurizing cavities 418, 438. In some applications the fluid cavities 418 may be desired to be interconnected to connect or to connect the fluid cavities 438 together. The Connecting the cavities effectively forms a single cavity in order any external forces within the single formed Distribute cavity.

Exemplary embodiments in particular for the second aspect of the invention (see FIGS. 1 to 13)

The respective membrane can be seen in FIGS. 1 to 10. Such a membrane can, however, in particular also in the embodiments according to FIGS. 12 and 13. Here too the membrane expediently back to the higher pressure having the side of the fibrous web arranged.

According to a second aspect of the invention, this results in a method for dewatering a fibrous web, in particular a paper or Cardboard web in which the fibrous web passes through a drainage zone is carried out in which it is at least partially due to an application with pressurized displacement fluid, in particular displacement gas, is dewatered, the fibrous web together with a porous membrane through the drainage zone and through the displacement fluid is applied through the membrane.

The membrane can be, for example, one made of film material with through holes existing membrane can be used.

The pressure of the displacement fluid acting on the membrane is preferably greater than the ambient pressure.

In particular, a membrane can also be used, such as they are described in connection with the first aspect of the invention has been.

The membrane can in particular be provided with coherent pores his.

Exemplary embodiments relating in particular to the third aspect of the invention (cf. Figures 10 and 11)

10 shows a schematic illustration of an exemplary embodiment a device 10 for dewatering a fibrous web 12. At the fibrous web 12 can in particular be a paper or Trade cardboard web.

The drainage device 10 comprises a drainage zone E, in of the fibrous web 13 at least partially by exposure with pressurized displacement fluid, in particular displacement gas 14, is drained. The fibrous web 12 becomes together with a membrane 16 and a sieve or felt belt 18 through the Dewatering device 10 performed, the fibrous web 12 through through the membrane 16 with the displacement gas 14 becomes. The screen or felt belt 18 is on the opposite side the fibrous web 12. The fibrous web 12 is thus between the Gas pressure applied membrane 16 and the screen or felt belt 18th led through the drainage zone E.

In the present exemplary embodiment, the drainage zone comprises E a displacement drainage unit 20 supplying the gas pressure, the with its gas outlet side 25 one formed, for example, by a roller Counter surface 24 is opposite to this one in the web running direction L to form an elongated gap 26 through which the membrane 16, the sieve or felt belt 18 and the intermediate fibrous web 12 are passed through.

As can be seen from FIG. 10, the dewatering zone E is divided into several sections in which the gas pressure applied can be set individually. In the present case, three such sections E1, E2 and E3 are provided, for example. In principle, any other number of sections is also possible. In particular, four or more sections are also conceivable. The pressures prevailing in the different sections E1, E2 and E3 are identified in FIG. 10 with p ₁ , p ₂ and p ₃ .

The different sections egg, i.e. in the present embodiment the sections E1, E2 and E3 can be sectioned across the width be, i.e. different pressures can be provided across the width his.

The counter surface 24 can be closed, open (grooved, ...) or permeable his.

As can be seen from FIG. 11, it can be viewed in the drainage direction a box 28 can be arranged behind the counter surface 24, which the Absorbs liquid and / or gas. The box 28 can be vacuumed i.e. be provided as a suction box. Again, in the direction of web travel L again several zones Si can be provided, which have different Pressing (e.g. overpressing and / or suppressing) is applied can be. In the present case, for example, there are three again Zones S1, S2 and S3 are provided. Basically, however, is also here any other number of zones is possible again. At positions 30 For example, liquid or gas can be removed.

Otherwise, the embodiment according to FIG. 11 has at least in again essentially the same structure as that of FIG. 10 corresponding parts are assigned the same reference numerals.

With these drainage devices 10, the result of the displacement drainage process in terms of final dryness and technical properties of the finished fibrous web 12 such as the specific volume, the porosity, the Surface roughness and / or the like can be controlled in a targeted manner. to The created drainage control process can be controlled Gas pressure varies along the drainage zone in the desired manner become. Thus, the drainage process can be carried out directly during operation can be set. For example, gentle drainage of paint at a low gas pressure. Will be a high one Final dryness is required so that the gas pressure in the rear Sections of drainage zone E are increased accordingly. Becomes on the other hand, a high volume is required for the finished fibrous web 12, so can the gas pressure in the rear sections of the drainage zone E set accordingly low. It is therefore particularly also a respective pressure profile can be set, for example, in the machine direction.

Here, too, a membrane can be used in particular, such as they are described in connection with the first aspect of the invention has been. The membrane can in particular also be connected Pores.

Exemplary embodiments relating in particular to the fourth aspect of the invention (cf. Figures 12 and 13)

12 shows a schematic representation of a first embodiment a device 10 for dewatering a fibrous web 12. In the Fibrous web 12 can in particular be a paper or cardboard web act.

The drainage device 10 includes a displacement drainage zone E, in which the fibrous web 12 at least partially by a Exposure to displacement fluid, here e.g. Displacement gas 14, is drained.

A press 16 is connected upstream of the displacement drainage zone E. The fibrous web 12 is first through the upstream press 16 and then passed through the displacement drainage zone E.

In the present exemplary embodiment, the upstream press is 16 formed by a shoe press.

The fibrous web 12 is together in the present embodiment with a screen or felt belt 18 through the press 16 and the displacement drainage zone E led.

In the present exemplary embodiment, the drainage zone E comprises a displacement drainage unit 20 with its gas outlet side opposes a counter roll 22, via which the displacement gas 14 acted upon fibrous web 12 and the sieve or felt belt 18 out are.

The embodiment according to FIG. 13 differs from that of FIG. 12 only in that as the displacement drainage zone E upstream press 16 'a roller press is provided. Furthermore This drainage device 10 has the same structure as that in FIG 12 shown device. Corresponding parts are assigned the same reference numerals.

In principle, a downstream mechanical press can also be provided his.

In the drainage devices shown, the extent the leaf compression and the amount of gas pressure applied separately to be controlled. It is particularly possible to determine the result of the Displacement drainage process in relation to the final Dryness and paper technology properties of the finished fibrous web such as specific volume, porosity, surface roughness and / or to control the like in a targeted manner. By the of the displacement drainage zone upstream press can the nonwoven on the the desired size can be precompacted. This can increase the permeability of the nonwoven can be adjusted in the desired manner. By the decoupling of the drainage and compacting process can thus set the properties of the finished paper in a targeted manner become. If the fleece is heavily pre-compacted, more water can be released the fleece can be removed. This is particularly the case with such types of paper required, in which primarily a high dry content after the Press is required.

A membrane, in particular, can also be used here, too they are described in connection with the first aspect of the invention has been. The membrane can in particular also be connected Pores.

Basically, any combination of the different aspects the invention possible.

Claims (5)

Process for dewatering a fibrous web, in particular a paper or cardboard web, in which the fibrous web is passed through a dewatering zone in which it is at least partially dewatered by exposure to pressurized displacement fluid, in particular displacement gas,
wherein the fibrous web is guided together with a porous membrane through the dewatering zone and the displacement fluid is applied through the membrane. Method according to claim 1,
characterized in that a membrane consisting of film material with through holes is used as the membrane. Method according to claim 1 or 2,
characterized in that the pressure of the displacement fluid acting on the membrane is greater than the ambient pressure. Method according to one of claims 1 to 3,
characterized in that a membrane according to one of claims 1 to 9 is used as the membrane. Method according to one of claims 1 to 3,
characterized in that a membrane produced according to the method according to one of claims 10 to 19 is used as the membrane.

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