The utility model relates to a fluid pipeline, in particular to a sewer pipe used on a sink of an extruder. The sewer pipe provided with a cross service valve used on the sink of the extruder comprises the sewer pipe (2) the upper end of which is communicated with the bottom of the sink (1). The utility model is characterized in that the cross service valve (3) is additionally arranged at a turning of the sewer pipe (2); ports of the cross service valve (3) which are vertical to each other are communicated with the sewer pipe (2); detachable plug screws (4, 5) are arranged on the other ports of the cross service valve (3). The utility model has simple structure and convenient operation; the two plug screws only needs to be disassembled, sundries deposited in the cross service valve can be cleaned rapidly, the unhindered drain is ensured, the instable water flow and the overfall in the sink are avoided, thus the product quality is further ensured, and the environment pollution is reduced at the same time.