Arrangement for a wire section of a paper or board machine

A web is formed between two wire loops, in a wire section of a paper or board machine, in connection with which dewatering elements are placed and in which water is drained from a stock suspension from between the two wires. In the region of a twin-wire zone, a suction roll is placed within one wire loop and a suction box having a curved surface is situated in opposed relationship with the suction roll on the wire loop. After the suction box, the web is guided, due to the effect of a vacuum of the suction roll, forwards on the surface of the wire loop of the suction roll.