ENTWÄSSERUNGSELEMENT IN DER SIEBPARTIE EINER MATERIALBAHN-HERSTELLUNGSMASCHINE UND DECKEL DES ENTWÄSSERUNGSELEMENTS EINER MATERIALBAHN-HERSTELLUNGSMASCHINE

Entwässerungselement der Siebpartie einer Materialbahn-Herstellungsmaschine, wobei diese Siebpartie ein umlaufendes Langsieb (12) hat, das in Kontakt mit der Wand (16) des Entwässerungselements (10) gebracht ist, und diese Wand (16) eine nichtpulsierende Saugzone (18) aufweist, die wenigstens die Breite des Siebes (12) hat, wobei in Laufrichtung des Siebes (12) betrachtet hinter der Saugzone (18) in der besagten Wand (16) eine im Wesentlichen in Querrichtung der Materialbahn-Herstellungsmaschine verlaufende Austrittsrille (20) vorhanden ist. A forming section of a paper or board machine 10 in the forming section of a paper or board machine has a cover 36 having an outlet groove 20 between a suction zone 18 of circular holes and an outlet edge 40. A wire comes to the cover area from an inlet edge 38 and leaves from an outlet edge 40. The outlet groove 20 is essentially in the cross-machine direction of the cover 36. The suction zone accomplishes non-pulsating dewatering, and the outlet groove accomplishes pulsating dewatering. The non-pulsating suction zone first accomplishes good retention, and after this formation is improved on the outlet groove. When pulsating dewatering takes place in the same direction as non-pulsating dewatering and immediately after non-pulsating dewatering, the web formed has a particularly good formation potential. Potential marking caused by non-pulsating dewatering can also be removed efficiently by means of pulsating dewatering taking place on the same side.