AT509113B1 - CARDBOARD MACHINE - Google Patents

Abstract

A board machine includes a forming section in which a lower wire loop (11) forms a Fourdrinier wire section (T1) at the beginning of which a screen table (200) is arranged comprising at least one stationary, non-pulsating forming shoe (210). On the forming shoe (210) there is provided a shutter (211) provided with through holes (212) adjacent to the inner surface of the lower wire loop (11). A first headbox (100), which is a multi-layer headbox, promotes a pulp solution jet onto the forming shoe (210). The board machine further comprises a press section (P1), wherein a surface (Wa) of the web (W), which has been applied to the lower wire loop (11) is pressed against a smooth surface, a drying section (D1), in which the web (W) is dried with at least one group of cylinder dryers, and a coating section (400) on which at least the surface (Wa) of the web (W) which has been applied to the lower wire loop (11) is coated.

Claims (13)

Austrian Patent Office In the embodiment shown in Fig. 1, there is only one lower wire draw unit after the first Fourdrinier wire T1, but the invention also allows the use of a number of N upper Siebzugeinheiten, where N is an integer greater than or equal to one. The forming shoe 210 shown in Figure 3 and the peel-off tab 220 following it may use the same negative pressure. With webs that have a low basis weight or fibers that can be easily dewatered, very little squeezing is used in the forming shoe 210 and the peel-off baffle 220 so as not to remove too much water from the web. For webs that have a high basis weight or fibers that are only slightly dewatered, the web in the section of form shoe 210 may be over-compacted. In this case, the pulsation at the portion of the peel-off sheet 220 is intensified and the drainage is increased by increasing the negative pressure at the peel-off sheet 220, thereby releasing the condensed lower sheet side. In the embodiments shown in the figures, the non-pulsating forming shoe 210 is followed by the pulsating peel-off tab 220. In some situations, the non-pulsating forming shoe 210 is sufficient, i. H. there is no need for a pulsating peel-off tab 220. Further, the non-pulsating form-shoe 210 does not always necessarily require the negative pressure to intensify the drainage. The embodiments shown in the figures use a film coating, but it is also possible to use here, for example, a curtain coating. The embodiments shown in the figures use a center roller press, in which the web side, which has been applied to the lower screen, rests against the center roller. It is also possible to use a transfer belt around the center roll with the web surface resting against the lower wire bearing against the smooth surface of the transfer belt, which is impervious to water. Instead of the center roller press, it is also possible to use a separate press in which two press rollers form a press nip, which is limited only by itself. To a press roll of the separate press a transfer belt or a metal belt is guided, wherein the web surface, which has been applied to the lower screen, abuts the transfer belt or the metal strip. Only a few advantageous embodiments of the invention have been described above, and it will be apparent to one skilled in the art that various modifications can be made therein within the scope of the appended claims. 1. A method for forming a multilayer web, the method comprising the following steps: - forming a first Fourdrinier wire section (T1) on a lower wire (11), which revolves around a breast roll (12), at the beginning of a screening table ( 200), feeding a pulp solution jet with a first headbox (100) onto the screening table (200), guiding the web (W) onto a press section (P1) at which water from the web (W) enters at least pressing the web (W) onto a drying section (D1) on which the web (W) is dried with at least one drying group using drying cylinders, characterized in that the method further comprises the following steps: Forming the forming table (200) from at least one stationary, non-pulsating forming shoe (210), on which a diaphragm (211) is provided with passage openings (212), adjacent to the Innenflä the lower sieve (11), the openings (212) comprising holes or slots extending substantially in the machine's longitudinal direction, forming the first headbox (100) as a multi-layer headbox in which a 10/17 Austrian headbox is provided Patent Office AT509113 B1 2013-02-15 lower nozzle jet channel (102a) and at least one upper nozzle jet channel (102b) are provided, - pressing a surface (Wa) of the web (W), which has been applied to the lower wire (11), against a smooth surface of the press section (P1), - coating at least the surface (Wa) of the web (W), which has been applied to the lower wire (11), in a coating section (400). A method according to claim 1, characterized in that non-pulsating dewatering is performed with a forming shoe (210), the open area defined by the apertures (212) of the baffle (211) of the forming shoe being 30-90 %, advantageously 40-70% of the portion with openings (212) of the diaphragm (211) and that negative pressure (P) through the openings (212) of the diaphragm (211) is guided. 3. The method of claim 1 or 2, characterized in that a pulsating dewatering with a peel-off (220) is performed, which is arranged after the non-pulsating forming shoe (210). 4. The method according to any one of claims 1-3, characterized in that the press section is formed from a center roller press, wherein the surface (Wa) of the web (W), which has been applied to the lower wire (11), against the smooth metal surface a middle roll (70) is pressed. A method according to any one of claims 1-4, characterized in that a coating section is formed by a film coater (400), the web (W) passing between two rollers (410, 420), the coating covering the surface (Wa) of the web (W), which has been applied to the lower wire (11), takes place with a bright coating material and a coating of an opposite surface (Wb) of the web (W) takes place with starch glue. 6. The method according to any one of claims 1-5, characterized in that an upper Siebzugeinheit over the lower sieve (11) is formed, wherein an upper sieve (21) forms a second Fourdrinier sieve section (T2), at the beginning of a pulp Solution jet is supplied to a second headbox (110) which is a single-layer headbox to form a second sub-web (W2), and wherein the upper wire (21) additionally has a double-wire section (K1) connected to the lower wire (11 ) is formed such that there is a start at the double-wire section (K1) where the lower wire (11) and the upper wire (21) form a connection point (Y) of the partial webs, and an end at which the upper one Sieve (21) is separated from the lower wire (11), wherein a second partial web (W2) which has been formed on the second Fourdrinier wire section (T2), with a first partial web (W1), which on the first Fourdrinier Siebzugab section (T1) has been formed on the Ve Connection point (Y) is connected. A method according to any one of claims 1 to 5, characterized in that a double wire section (K1) is formed with the lower wire (11) and an upper wire (21) above it, being in the double wire section (K1 ) gives a start at which the lower wire (11) and the upper wire (21) join, and an end at which the upper wire (21) is separated from the lower wire (11), one non-pulsating and pulsating dewatering on the web (W) formed on the first Fourdrinier wire section (T1) on the double wire section (K1) with a dewatering element (80) within the upper wire loop (21). 11/17 Austrian Patent Office AT509113B1 2013-02-15 8. A board making machine comprising: - a forming section, at which a lower wire loop (11) forms a Fourdrinier wire section (T1) after a first breast roll (12), at the beginning of which a screening table (200) is arranged, - a first headbox (100), with which a pulp solution jet is conveyed onto the forming table (200), - a press section (P1), at which water is pressed out of the web (W) in at least one press nip, - a drying section (D1) wherein the web (W) is dried with at least one group of cylinder dryers, characterized in that - the sifting table (200) comprises at least one stationary, non-pulsating forming shoe (210) on which a diaphragm (211) is provided which cooperates with Through openings (212) is provided, adjacent to the inner surface of the lower screen (11), wherein the openings (212) holes or slots substantially in the longitudinal direction of the machine comprise, - the first headbox (100) a Mehrschich t head box, which comprises a lower jet channel (102a) and at least one upper jet channel (102b), - on the pressing portion (P1) is provided a smooth surface against which a surface (Wa) of the web (W) is pressed, which has applied to the lower wire (11), - the board machine further comprises a coating section (400) on which at least the web surface (Wa) which has been applied to the lower wire is coated. Board machine according to claim 8, characterized in that the open area delimited by the openings (212) of the aperture (211) of the forming shoe (210) is 30-90%, advantageously 40-70%, of the portion with openings (212) makes the shutter (211), and that the negative pressure (P) penetrates through the openings (212). 10. board machine according to claim 8 or 9, characterized in that on the non-pulsating form shoe (210) a pulsating peel-off (220) follows. A board machine according to any one of claims 8 - 10, characterized in that the press section comprises a center roller press against which the surface (Wa) of the web (W) resting against the lower wire (11) bears against the smooth surface of a web Center roller (70) is pressed. A board machine according to any one of claims 8-11, characterized in that the coating section comprises a film coater (400), the web (W) passing between two rollers (410, 420), the surface (Wa) of the web (W ) applied to the lower wire (11) is coated with a bright coating material and the opposite surface (Wb) of the web (W) is coated with starch glue. A board machine according to any one of claims 8-12, characterized in that the board machine further comprises an upper wire feed unit disposed above the lower wire (11) in which the upper wire (21) has a second Fourdrinier wire section (T2). at the beginning of which a second head box (110), which is a single-layer headbox, feeds a pulp solution jet for forming a second partial web (W2), and wherein the upper wire (21) further comprises a double-wire section (K1) forming the lower wire (11), and wherein at the double wire portion (K1) there is a starting portion in which the lower wire (11) and the upper wire (21) form a connection point (Y) of the partial webs, and an end portion in that the upper wire (21) is separated from the lower wire (11), the second part web (W2) formed on the second Fourdrinier wire (T2) having a first part web 12/17