EP1389510A2 - Apparatus for making webs - Google Patents

Abstract

The machine (10) to produce a fiber web (38), e.g. for the production of fiberboards, has a recirculating press belt (12) forming a press gap with a counter surface (14) at a drum (16). A number of successive press units (20) are deployed in the direction (L) of web travel, to press the belt with the web against the counter surface. The press units have at least a partially independent control (30) to set the pressure applied to the web to set and adjust its bulk density profile, and at least one press unit is an adjustable bending roller. The press gap can be heated at least on one side.

Description

The invention relates to a device for producing material webs with a rotating, with a moving counter surface a press nip forming press belt and with several on top of each other in the direction of web travel following pressing units, through which the rotating press belt can be pressed against the moving counter surface in the press nip area.

In the field of fiber and particle board production, a quantity of chip or fiber provided with 6 to 22% glue is usually compressed into plates between a heated drum and a rotating steel belt. The diameter of the drum is usually in a range from 2 to 5 m. The plates obtained usually have a thickness in a range from 1.5 to 12 mm. The steel strip, which is also hot, is pressed against the drum by at least one roller (cf., for example, DE 42 43 917 C). In older devices of the type mentioned, the rollers are at a relatively large mutual distance. In the area between the rollers, which are relatively far apart from one another, the tape tension now results in only a relatively low contact pressure on the fiber cake, which can be, for example, in a range from 20 to 25 N / cm ² . In contrast, the line load between a relatively hard roller and the drum can be, for example, 10,000 N / cm. In a device of the type mentioned, which is known from EP 0 776 742 B, the deflection adjustment rollers are now closer behind one another in the web running direction, which on the one hand reduces the time interval between the force peaks on the fiber cake and on the other hand keeps the contact pressure on the fiber cake between the force peaks at a higher level , To optimize the system, only the path has been taken so far to replace relatively few larger rolls with a diameter of, for example, approximately 1.5 m by a plurality of smaller deflection adjusting rolls with a diameter of, for example, approximately 0.32 m lying directly behind one another.

The invention has for its object to further optimize the device of the type mentioned. In particular, the fact should be taken into account that at the beginning of the pressing process, where the heat has not yet penetrated too deeply into the cake, the surface of the material web to be formed, for example fiber or chipboard, can be hard compacted, for example up to about 1000 kg / m ³ , while the inner area is still in a relatively "crumbly" form. In contrast, in a second phase, ie after the high temperatures have penetrated with pressure, the inner layer or the inner region can be compressed, for example, to about 600 kg / m ³ . The optimization should therefore also take into account these circumstances in particular.

This object is achieved in that the in the web running direction successive pressing units for setting the respective pressure cross profile at least partially separated from each other are controllable. At least one pressing unit is preferably through a deflection adjustment roller is formed.

Because of the at least partially independent control of the individual pressing units can affect the quality of the end product be significantly improved. For example, the outer and inner layers or areas of the relevant material web largely independent of one another in terms of their bulk density to be influenced. The previously related to different Material thicknesses and correspondingly different speeds Problems can arise through the independent pressure control be largely eliminated. The bulk density is now also in the cross section more adjustable. With the use of closely consecutive Pressure units or rollers of smaller diameter and the resulting achieved higher peak power density is also achieved that less Glue bridges are destroyed again, so that less glue is required is.

The pressing units which follow one another in the web running direction can always be grouped together and in groups can be controlled separately.

The one between the rotating press belt and the moving counter surface Press nip formed can be heated on one or both sides.

It is advantageous to have at least one in the direction of web travel considered deflection adjusting roller assigned to the front area of the press nip the bulk density of the material web and in particular the resulting in the surface area control density and / or adjustable. It is particularly about the respective deflection adjustment roller the bulk density profile can also be controlled and / or regulated.

Furthermore, it is also an advantage if at least one person is interested a further press nip area connecting a front press nip area assigned pressing unit the bulk density of the material web and in particular the gross density resulting in their interior tax and / or is adjustable. It is particularly about the respective pressing unit again the bulk density cross profile can be controlled and / or regulated.

According to a preferred practical embodiment of the invention Device is at least one in the web running direction looks at the front area of the press nip associated with the pressure unit the resulting bulk density in the surface area and at least another adjoining the front press nip area Press nip area associated pressure unit which is located inside the The resulting material density can be controlled and / or regulated.

The pressure unit assigned to the front press nip area is preferred or group of pressing units separately from the other Press nip area associated pressing unit or group of pressing units controllable.

It is particularly advantageous if at least one of them is one another press nip area adjoining a front press nip area assigned pressure unit control and / or the thickness of the material web is adjustable. The particular pressure unit is in particular again control and / or the thickness cross profile of the material web adjustable.

The bulk density inside the material web and the Web thickness in the same press nip area or in successive Press nip areas are controlled or regulated.

A respective deflection adjustment roller expediently comprises one revolving roll shell each, one penetrating the roll shell non-rotatable yoke and between the roller shell and the Yoke arranged pressure elements, which are distributed over the width of the roller and are at least partially controllable separately. The pressing elements can in particular also be grouped together and in groups can be controlled separately. In particular, hydraulic Pressure element can be provided, each a type of cylinder / piston unit form.

For example, in the production of fiberboard or particle board As much compression as possible is desired in the inlet area of the press nip. Essentially only the cover layers are influenced there. In the further course, lower pressures become for molding suffice.

According to an expedient practical embodiment of the invention The device is therefore in the direction of web travel successive pressure units formed by pressure rollers, which at least partially have roller coverings of different hardness. The hardness of a respective roller covering is preferably dependent selected from the location of the relevant pressure roller. advantageously, can be a front area of the Press nip can be assigned at least one pressure roller, the roller covering has a modulus of elasticity that is higher or lower than the modulus of elasticity of the roller covering at least one subsequent one Press nip area assigned to the pressure roller.

The press nip preferably has a curved course. The moving Counter surface can in particular by a rotating press drum be educated.

The moving counter surface or the rotating press drum is preferred heated.

The rotating press belt can advantageously be made by a steel belt be educated.

The rotating press belt or steel belt is also preferably again heated. Induction heating can be used, for example, to heat the steel strip be provided.

In a preferred practical embodiment of the invention Device are the successive in the web running direction Press units at least partially arranged in close succession. In this case, the pressing units can, for example, also form groups be summarized. The pressure units are within the respective groups then arranged as close to each other as possible, while possibly also between two respective groups relatively larger distance can be provided.

The press drum forming the counter surface can in particular be one Diameter in a range from about 3 to about 5 m, for example have.

If the counter surface is formed by a press drum, the in Direction of web running successive pressure units or rollers each have a diameter that is preferably many times smaller than the diameter of the press drum.

The pressing units can also be at least partially heated again his.

Another advantageous embodiment of the device according to the invention is characterized by the fact that the pressure units Variable longitudinal compression profiles in web direction is adjustable. This longitudinal pressure profile is preferably tax and / or adjustable.

In certain cases it is also advantageous if the direction of travel successive pressing units can be controlled so that a generally decreasing longitudinal pressure profile in the direction of web travel results.

In an expedient practical embodiment of the invention The press belt is both over a partial area of a device the counter surface forming press drum as well as tensioning and / or Deflection rollers guided. In this case, one in the entrance area of the Press nip provided tensioning or deflecting roller simultaneously as Press roller provided, over which the press belt against the counter surface can be pressed.

The pressing units can have at least one control and / or Control device can be controlled accordingly. It is about one such control and / or regulating device preferably at least one Target bulk density profile can be specified.

It is expedient to have at least one device for measuring the Gross density of the material web is provided. This can be in the direction of web travel considered in particular to be arranged behind the press nip. Conveniently, is such a bulk density measuring device to the control and / or Control device connected.

It is also advantageous to have at least one device for measuring the Thickness of the material web is provided. This thickness measuring device too is preferably viewed behind the press nip in the direction of web travel arranged. The thickness measuring device can also be connected to the Control and / or regulating device may be connected.

The device according to the invention is advantageously in particular applicable for the production of fiberboard webs that can be divided into individual panels, Chipboard sheets and / or the like made of a lignocellulosic and / or cellulose-containing particles and at least one binder containing fleece.

The device according to the invention is advantageously in particular also for the production of fiber, chip, HDF, MDF, LDF and / or OSB boards can be used.

Basically, the device according to the invention is also, for example in a paper machine, a calender or a printing machine usable.

Any other uses are conceivable.

Fig. 1

eine rein schematische Darstellung einer Vorrichtung zur Herstellung von Materialbahnen und

Fig. 2

ein Ausschnitt A der Vorrichtung gemäß Fig. 1 in vergrößerter Darstellung.

The invention is explained below using an exemplary embodiment with reference to the drawing; in this show:

Fig. 1

a purely schematic representation of a device for the production of material webs and

Fig. 2

a section A of the device of FIG. 1 in an enlarged view.

1 shows a device 10 for a purely schematic illustration Production of material webs 38, such as in individual plates divisible fiberboard webs, chipboard webs and / or the like from a lignocellulosic and / or cellulosic particle and fleece containing at least one binder. The device 10 is for example also for the production of HDF, MDF, LDF and / or OSB boards can be used.

The device 10 comprises, for example, a steel band revolving press belt 12, which with a moving counter surface 14, here, for example, formed by the surface of a press drum 16, defines a press nip 18 in which the for the production of the material web 38 serving starting material is compressed.

The device 10 also includes a plurality of in the web running direction L successive, here for example as deflection adjustment rollers 20 provided pressure units through which the rotating Press belt 12 in the area of the press nip 18 against the moving counter surface 14, so here can be pressed against the press drum 16.

As can be seen in particular from FIG. 2, the Deflection adjusting rollers 20 each have a rotating roller jacket 22, a non-rotatable yoke 24 passing through the roller jacket 22 and pressure elements arranged between the roll shell 22 and the yoke 24 26, which is distributed over the roller width and at least partially can be controlled separately. The pressing elements 26 can be separated individually controllable or combined into groups and in groups can be controlled separately.

The deflection adjustment rolls following one another in the web running direction L. 20 are at least for setting the respective pressure cross profile partially controllable separately.

In the present case, the deflection adjustment rollers 20 are two Groups I, II combined. At least the two groups of rollers are included I, II separately controllable. Basically you can however, the deflection adjustment rollers 20 within a respective one Group I, II can be controlled at least partially separately.

The between the rotating press belt 12 and the moving counter surface 14 or the press drum 16 formed press nip 18 is at least heatable on one side and preferably on both sides. So it can, for example both the press drum 16 and here by a steel belt formed press belt 12 can be heated. For heating the press belt 12 In particular, inductive heating can be provided.

Over one or more of a front viewed in the web running direction L. Deflection adjusting rollers 20 assigned to the area of the press nip 18 can in particular the bulk density of the material web 38, and preferably the bulk density resulting in their surface area controlled and / or regulated. So especially about the first Group I of deflection compensation rollers 20 which are in the surface area the bulk density resulting from the material web 38 to be influenced.

Moreover, about the respective deflection adjustment rollers 20 in particular also the bulk density cross profile, here in particular that in the Surface area of the material web 38 resulting bulk density cross profile controllable and / or adjustable.

Over one or more one at the front press nip area subsequent deflection adjustment rollers assigned to further press nip area 20 can in particular be located inside the material web 38 resulting density can be controlled and / or regulated. This can in the present case, for example, via group II of deflection adjustment rollers 20 done.

Also in the present case is about the respective deflection adjustment rollers 20 in particular also the bulk density cross profile in the desired Wise controllable and / or adjustable.

It is thus possible, for example, to use the first group I of deflection adjustment rollers 20 primarily in the surface area of the material web 38 resulting bulk density and over the another group II of deflection adjustment rollers 20 primarily the resulting in the desired density inside the material web 38 Way to control and / or regulate.

Group I of the front press nip area is from Deflection adjusting rollers 20 are preferably separate from the others Group II of deflection adjustment rollers assigned to the press nip area 20 controllable.

Over one or more of them at a front press nip area subsequent deflection adjustment rollers assigned to further press nip area 20 can in particular also the thickness of the material web 38 be controlled and / or regulated in the desired manner. It is expediently via the respective deflection adjustment rollers 20 the transverse thickness profile of the material web 38 can also be controlled or regulated.

The deflection adjustment rollers provided within a respective group I, II 20 are each dense when viewed in the web running direction L. arranged one behind the other.

The press drum 16 can in particular have a diameter in one area from about 3 to about 5 m, for example.

As can be seen in particular from FIG. 1, the in Web running direction L successive deflection adjustment rollers 20 each have a diameter that is many times smaller than that Diameter of the pressing drum 16 forming the counter surface 14.

Basically, this can also be done using the deflection adjustment rollers 20 longitudinal pressure profile in the web running direction L variably adjustable his. This longitudinal pressure profile can also control and / or be controllable. The deflection adjustment rollers can 20 can be controlled in such a way that one in the web running direction L generally decreasing longitudinal pressure profile results.

As can be seen in particular from FIG. 1, this is for example Press band 12 formed by a steel band both over a partial area the press drum 16 and also via tensioning and / or deflecting rollers 28 out. The one provided in the entrance area of the press nip 18 can Roller 28 can be provided at the same time as a press roller over which the Press belt 12 can be pressed against the press drum 16.

The deflection adjustment rollers 20 can in particular at least a control and / or regulating device 30 is controlled accordingly become. The control device 30 can display 32 for Playback assigned to the relevant property profiles, for example his.

A respective target bulk density profile can be controlled and / or regulated 30 be specified. In addition, this tax and / or Control device 30 optionally also at least one target thickness profile be specified.

In the present case, both a device 34 for measuring the Gross density of the material web 38 as well as a device 36 for measurement the thickness of the material web 38 is provided, each in the web running direction L viewed behind the press nip 18 are arranged. So it will the thickness or bulk density of the finished material web 38 is measured.

The raw density measuring device 34 and the thickness measuring device 36 are connected to the control and / or regulating device 30. The relevant actual values, in particular the respective actual profile can specify, in the control and / or regulating device 30 are compared with the target values or the target profiles. The deflection adjustment rollers 20 can via the control and / or regulating device 30 can then be controlled in such a way that the actual values or adjust actual profiles to the target values or target profiles. there can e.g. also recorded actual longitudinal profiles and in particular again by a corresponding regulation to corresponding ones Target longitudinal profiles are adjusted. Via the control and / or regulating device 30 can thus, for example, both target pressure cross profiles as well as target longitudinal pressure profiles to which the respective actual pressures are then adjusted accordingly.

The device 10 just described can be used, for example, for Production of fiberboard webs that can be divided into individual panels, Chipboard sheets and / or the like made of a lignocellulose and / or cellulose-containing particles and at least one binder Fleece. It is particularly useful for the production of fiber, Chipboard, HDF, MDF, LDF and / or OSB board. Basically is also a use in a paper machine, a calender, one Printing machine and / or the like conceivable.

LIST OF REFERENCE NUMBERS

10

contraption

12

Press belt, steel belt

14

counter surface

16

press drum

18

press nip

20

Press unit, deflection adjustment roller

22

roll shell

24

yoke

26

pressing unit

28

Chip and / or deflection roller

30

Control and / or regulating device

32

display

34

Rohdichtemesseinrichtung

36

Thickness measuring device

38

web

L

Web direction

I

Group of deflection adjustment rollers

II

Group of deflection adjustment rollers

Claims (43)

Device (10) for the production of material webs (38) with a circumferential press belt (12) forming a press nip (18) with a moving counter surface (14) and with several pressure units (20) following one another in the web running direction (L), through which the revolving press belt (12) can be pressed against the moving counter surface (14) in the press nip area,
characterized in that the pressing units (20) following one another in the web running direction (L) can be controlled at least partially separately from one another for setting the respective pressing pressure transverse profile. Device according to claim 1,
characterized in that at least one pressing unit is formed by a deflection adjusting roller (20). Device according to claim 1 or 2,
characterized in that the pressing units (20) following one another in the web running direction (L) can be controlled separately from one another at least in groups. Device according to one of the preceding claims,
characterized in that the press nip (18) formed between the rotating press belt (12) and the moving counter surface (14) can be heated at least on one side. Device according to claim 4,
characterized in that the press nip (18) can be heated on both sides. Device according to one of the preceding claims,
characterized in that the bulk density of the material web (38) and in particular the bulk density resulting in its surface area can be controlled and / or regulated via at least one pressing unit (20) associated with a front region of the press nip (18) viewed in the web running direction (L). Apparatus according to claim 6,
characterized in that the bulk density cross profile can be controlled and / or regulated via the respective pressing unit (20). Device according to one of the preceding claims,
characterized in that the bulk density of the material web (38) and in particular the bulk density resulting inside it can be controlled and / or regulated via at least one pressure unit (20) assigned to a further press nip region adjoining a front press nip area. Device according to claim 8,
characterized in that the bulk density cross profile can be controlled and / or regulated via the respective pressing unit (20). Device according to one of the preceding claims,
characterized in that the raw density resulting in the surface area of the material web (38) is assigned via at least one pressing unit (20) associated with a front area of the press nip (18) viewed in the web running direction (L) and at least one further press nip area adjoining the front press nip area assigned pressing unit (20) the bulk density resulting in the interior of the material web (38) can be controlled and / or regulated. Device according to one of the preceding claims,
characterized in that the pressing unit (20) or group (I) of pressing units (20) assigned to the front press nip area can be controlled separately from the pressing unit (20) or group (II) of pressing units (20) assigned to the further pressing nip area. Device according to one of the preceding claims,
characterized in that the thickness of the material web (38) can be controlled and / or regulated by means of at least one pressure unit (20) associated with a further press nip area adjoining a front press nip area. Device according to claim 12,
characterized in that the thickness cross profile of the material web can be controlled and / or regulated via the respective pressing unit (20). Device according to one of the preceding claims,
characterized in that a respective pressing unit (20) comprises a rotating roller jacket (22), a non-rotatable yoke (24) passing through the roller jacket (22) and pressure elements (26) arranged between the roller jacket (22) and the yoke (24) distributed over the roller width and at least partially controllable separately. Device according to one of the preceding claims,
characterized in that the pressing units (20) following one another in the web running direction (L) are formed by pressing rollers which at least partially have roller coverings of different hardness. Device according to claim 15,
characterized in that the hardness of a respective roller covering is selected depending on the location of the pressure roller in question. Device according to claim 15 or 16,
characterized in that at least one pressure roller is assigned to a front region of the press nip, viewed in the direction of web travel, the roller covering of which has an elastic modulus that is higher or lower than the elastic modulus of the roller covering at least one pressure roller assigned to a subsequent further press nip region. Device according to one of the preceding claims,
characterized in that the press nip (18) has a curved course. Device according to one of the preceding claims,
characterized in that the moving counter surface (14) is formed by a rotating press drum (16). Device according to one of the preceding claims,
characterized in that the moving counter surface (14) or the rotating press drum (16) can be heated. Device according to one of the preceding claims,
characterized in that the circumferential press belt (12) is formed by a steel belt. Device according to claim 21,
characterized in that the rotating press belt (12) or steel belt can be heated. Device according to claim 22,
characterized in that induction heating is provided for heating the steel strip (12). Device according to one of the preceding claims,
characterized in that the pressing units (20) following one another in the web running direction (L) are arranged at least partially closely one behind the other. Device according to one of the preceding claims,
characterized in that the pressing drum (16) forming the counter surface (18) has a diameter in a range from approximately 3 to approximately 5 m. Device according to one of the preceding claims,
characterized in that the pressing units (20) which follow one another in the web running direction (L) each have a diameter which is preferably many times smaller than the diameter of the pressing drum (16) forming the counter surface (14). Device according to one of the preceding claims,
characterized in that the pressing units (20) are at least partially heatable. Device according to one of the preceding claims,
characterized in that the longitudinal pressing pressure profile which results from the pressing units (20) in the web running direction (L) is variably adjustable. Device according to claim 28,
characterized in that the longitudinal pressure profile can be controlled and / or regulated. Device according to one of the preceding claims,
characterized in that the pressing units (20) following one another in the web running direction (L) can be controlled in such a way that a longitudinally decreasing or increasing pressing pressure profile results in the web running direction (L). Device according to one of the preceding claims,
characterized in that the press belt (12) is guided both over a partial area of a press drum (16) forming the counter surface (14) and over tensioning and / or deflecting rollers (28). Apparatus according to claim 31,
characterized in that a provided in the entrance area of the press nip. Deflection roller (28) is simultaneously provided as a press roller, via which the press belt (12) can be pressed against the counter surface (14). Device according to one of the preceding claims,
characterized in that the pressing units (20) can be controlled accordingly via at least one control and / or regulating device (30). Apparatus according to claim 33,
characterized in that at least one target bulk density profile can be predetermined via the control and / or regulating device (30). Device according to one of the preceding claims,
characterized in that at least one device (34) is provided for measuring the bulk density of the material web. Apparatus according to claim 35,
characterized in that the raw density measuring device (34), viewed in the web running direction (L), is provided behind the press nip (18). Apparatus according to claim 35 or 36,
characterized in that the bulk density measuring device (34) is connected to the control and / or regulating device. Device according to one of the preceding claims,
characterized in that at least one device (36) is provided for measuring the thickness of the material web (38). Device according to claim 38,
characterized in that the thickness measuring device (36), viewed in the web running direction (L), is provided behind the press nip (18). Device according to claim 38 or 39,
characterized in that the thickness measuring device (34) is connected to the control and / or regulating device (30). Use of the device (10) according to one of the preceding Claims for the production of fiberboard webs which can be divided into individual panels, Chipboard sheets and / or the like a lignocellulosic and / or cellulosic particle and at least a nonwoven containing binder. Use of the device according to one of the preceding claims for the production of fiber, chip, HDF, MDF, LDF and / or OSB boards. Use of the device according to one of the preceding claims in a paper machine, a calender or one Press.

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